WorldWideScience

Sample records for adhesive protein inspired

  1. Bio-Inspired Dry Adhesives

    Science.gov (United States)

    2013-02-01

    of mask respirators with bio -inspired adhesive integrated into their peripheral seals; and (2) assessment of the competitive position of the new bio -inspired adhesives in broader fields of application.

  2. Switchable bio-inspired adhesives

    Science.gov (United States)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  3. High-performance mussel-inspired adhesives of reduced complexity

    National Research Council Canada - National Science Library

    Ahn, B Kollbe; Das, Saurabh; Linstadt, Roscoe; Kaufman, Yair; Martinez-Rodriguez, Nadine R; Mirshafian, Razieh; Kesselman, Ellina; Talmon, Yeshayahu; Lipshutz, Bruce H; Israelachvili, Jacob N; Waite, J Herbert

    2015-01-01

    .... Translation of mussel-inspired wet adhesion typically entails catechol functionalization of polymers and/or polyelectrolytes, and solution processing of many complex components and steps that require...

  4. Biophysically inspired model for functionalized nanocarrier adhesion to cell surface: roles of protein expression and mechanical factors

    Science.gov (United States)

    Ramakrishnan, N.; Tourdot, Richard W.; Eckmann, David M.; Ayyaswamy, Portonovo S.; Muzykantov, Vladimir R.; Radhakrishnan, Ravi

    2016-06-01

    In order to achieve selective targeting of affinity-ligand coated nanoparticles to the target tissue, it is essential to understand the key mechanisms that govern their capture by the target cell. Next-generation pharmacokinetic (PK) models that systematically account for proteomic and mechanical factors can accelerate the design, validation and translation of targeted nanocarriers (NCs) in the clinic. Towards this objective, we have developed a computational model to delineate the roles played by target protein expression and mechanical factors of the target cell membrane in determining the avidity of functionalized NCs to live cells. Model results show quantitative agreement with in vivo experiments when specific and non-specific contributions to NC binding are taken into account. The specific contributions are accounted for through extensive simulations of multivalent receptor-ligand interactions, membrane mechanics and entropic factors such as membrane undulations and receptor translation. The computed NC avidity is strongly dependent on ligand density, receptor expression, bending mechanics of the target cell membrane, as well as entropic factors associated with the membrane and the receptor motion. Our computational model can predict the in vivo targeting levels of the intracellular adhesion molecule-1 (ICAM1)-coated NCs targeted to the lung, heart, kidney, liver and spleen of mouse, when the contributions due to endothelial capture are accounted for. The effect of other cells (such as monocytes, etc.) do not improve the model predictions at steady state. We demonstrate the predictive utility of our model by predicting partitioning coefficients of functionalized NCs in mice and human tissues and report the statistical accuracy of our model predictions under different scenarios.

  5. Strong, reversible underwater adhesion via gecko-inspired hydrophobic fibers.

    Science.gov (United States)

    Soltannia, Babak; Sameoto, Dan

    2014-12-24

    Strong, reversible underwater adhesion using gecko-inspired surfaces is achievable through the use of a hydrophobic structural material and does not require surface modification or suction cup effects for this adhesion to be effective. Increased surface energy can aid in dry adhesion in an air environment but strongly degrades wet adhesion via reduction of interfacial energy underwater. A direct comparison of structurally identical but chemically different mushroom shaped fibers shows that strong, reversible adhesion, even in a fully wetted, stable state, is feasible underwater if the structural material of the fibers is hydrophobic and the mating surface is not strongly hydrophilic. The exact adhesion strength will be a function of the underwater interfacial energy between surfaces and the specific failure modes of individual fibers. This underwater adhesion has been calculated to be potentially greater than the dry adhesion for specific combinations of hydrophobic surfaces.

  6. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives

    OpenAIRE

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-01-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structur...

  7. Human climbing with efficiently scaled gecko-inspired dry adhesives.

    Science.gov (United States)

    Hawkes, Elliot W; Eason, Eric V; Christensen, David L; Cutkosky, Mark R

    2015-01-01

    Since the discovery of the mechanism of adhesion in geckos, many synthetic dry adhesives have been developed with desirable gecko-like properties such as reusability, directionality, self-cleaning ability, rough surface adhesion and high adhesive stress. However, fully exploiting these adhesives in practical applications at different length scales requires efficient scaling (i.e. with little loss in adhesion as area grows). Just as natural gecko adhesives have been used as a benchmark for synthetic materials, so can gecko adhesion systems provide a baseline for scaling efficiency. In the tokay gecko (Gekko gecko), a scaling power law has been reported relating the maximum shear stress σmax to the area A: σmax ∝ A(-1/4). We present a mechanical concept which improves upon the gecko's non-uniform load-sharing and results in a nearly even load distribution over multiple patches of gecko-inspired adhesive. We created a synthetic adhesion system incorporating this concept which shows efficient scaling across four orders of magnitude of area, yielding an improved scaling power law: σmax ∝ A(-1/50). Furthermore, we found that the synthetic adhesion system does not fail catastrophically when a simulated failure is induced on a portion of the adhesive. In a practical demonstration, the synthetic adhesion system enabled a 70 kg human to climb vertical glass with 140 cm(2) of adhesive per hand.

  8. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  9. A biodegradable and biocompatible gecko-inspired tissue adhesive.

    Science.gov (United States)

    Mahdavi, Alborz; Ferreira, Lino; Sundback, Cathryn; Nichol, Jason W; Chan, Edwin P; Carter, David J D; Bettinger, Chris J; Patanavanich, Siamrut; Chignozha, Loice; Ben-Joseph, Eli; Galakatos, Alex; Pryor, Howard; Pomerantseva, Irina; Masiakos, Peter T; Faquin, William; Zumbuehl, Andreas; Hong, Seungpyo; Borenstein, Jeffrey; Vacanti, Joseph; Langer, Robert; Karp, Jeffrey M

    2008-02-19

    There is a significant medical need for tough biodegradable polymer adhesives that can adapt to or recover from various mechanical deformations while remaining strongly attached to the underlying tissue. We approached this problem by using a polymer poly(glycerol-co-sebacate acrylate) and modifying the surface to mimic the nanotopography of gecko feet, which allows attachment to vertical surfaces. Translation of existing gecko-inspired adhesives for medical applications is complex, as multiple parameters must be optimized, including: biocompatibility, biodegradation, strong adhesive tissue bonding, as well as compliance and conformability to tissue surfaces. Ideally these adhesives would also have the ability to deliver drugs or growth factors to promote healing. As a first demonstration, we have created a gecko-inspired tissue adhesive from a biocompatible and biodegradable elastomer combined with a thin tissue-reactive biocompatible surface coating. Tissue adhesion was optimized by varying dimensions of the nanoscale pillars, including the ratio of tip diameter to pitch and the ratio of tip diameter to base diameter. Coating these nanomolded pillars of biodegradable elastomers with a thin layer of oxidized dextran significantly increased the interfacial adhesion strength on porcine intestine tissue in vitro and in the rat abdominal subfascial in vivo environment. This gecko-inspired medical adhesive may have potential applications for sealing wounds and for replacement or augmentation of sutures or staples.

  10. A biodegradable and biocompatible gecko-inspired tissue adhesive

    OpenAIRE

    Mahdavi, Alborz; Ferreira, Lino; Sundback, Cathryn; Nichol, Jason W.; Chan, Edwin P.; Carter, David J. D.; Bettinger, Chris J.; Patanavanich, Siamrut; Chignozha, Loice; Ben-Joseph, Eli; Galakatos, Alex; Pryor, Howard; Pomerantseva, Irina; Masiakos, Peter T.; Faquin, William

    2008-01-01

    There is a significant medical need for tough biodegradable polymer adhesives that can adapt to or recover from various mechanical deformations while remaining strongly attached to the underlying tissue. We approached this problem by using a polymer poly(glycerol-co-sebacate acrylate) and modifying the surface to mimic the nanotopography of gecko feet, which allows attachment to vertical surfaces. Translation of existing gecko-inspired adhesives for medical applications is complex, as multipl...

  11. A gecko-inspired double-sided adhesive.

    Science.gov (United States)

    Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

    2013-12-21

    Geckos' outstanding abilities to adhere to various surfaces are widely credited to the large actual contact areas of the fibrillar and hierarchical structures on their feet. These special features regulate the essential structural compliance for every attachment and thus provide robust yet reversible adhesions. Inspired by gecko's feet and our commonly used double-faced tape, we have successfully fabricated a gecko-inspired double-sided dry adhesive by using porous anodic alumina template assisted nano-wetting on a stiff polymer. It was determined that the obtained 2-sided structure showed largely decreased effective stiffness compared with its 1-sided counterpart, which favored better compliance and interfacial integrity. We also demonstrated that the repeatable double-sided adhesive improved the macroscopic normal and shear adhesion capacities over the widely-studied 1-side structure by ~50% and ~85%, respectively. By using the synthetic double-sided adhesive, the usage of traditional pressure-sensitive/chemical adhesives could be well avoided. Besides, the double-sided nanostructures showed great potential in finding new interesting properties and practical applications for the synthetic dry adhesives.

  12. A microfabricated gecko-inspired controllable and reusable dry adhesive

    Science.gov (United States)

    Chary, Sathya; Tamelier, John; Turner, Kimberly

    2013-02-01

    Geckos utilize a robust reversible adhesive to repeatedly attach and detach from a variety of vertical and inverted surfaces, using structurally anisotropic micro- and nano-scale fibrillar structures. These fibers, when suitably articulated, are able to control the real area of contact and thereby generate high-to-low van der Waals forces. Key characteristics of the natural system include highly anisotropic adhesion and shear forces for controllable attachment, a high adhesion to initial preload force ratio (μ‧) of 8-16, lack of inter-fiber self-adhesion, and operation over more than 30 000 cycles without loss of adhesion performance. A highly reusable synthetic adhesive has been developed using tilted polydimethylsiloxane (PDMS) half-cylinder micron-scale fibers, retaining up to 77% of the initial value over 10 000 repeated test cycles against a flat glass puck. In comparison with other gecko-inspired adhesives tested over 10 000 cycles or more thus far, this paper reports the highest value of μ‧, along with a large shear force of ˜78 kPa, approaching the 88-226 kPa range of gecko toes. The anisotropic adhesion forces are close to theoretical estimates from the Kendall peel model, quantitatively showing how lateral shearing articulation in a manner similar to the gecko may be used to obtain adhesion anisotropy with synthetic fibers using a combination of tilt angle and anisotropic fiber geometry.

  13. Cohesion and Adhesion with Proteins

    Science.gov (United States)

    Charles R. Frihart

    2016-01-01

    With increasing interest in bio-based adhesives, research on proteins has expanded because historically they have been used by both nature and humans as adhesives. A wide variety of proteins have been used as wood adhesives. Ancient Egyptians most likely used collagens tobond veneer to wood furniture, then came casein (milk), blood, fish scales, and soy adhesives, with...

  14. Gecko-Inspired, Controlled Adhesion and Its Applications

    Science.gov (United States)

    Menguc, Yigit

    This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles

  15. A design methodology for biologically inspired dry fibrillar adhesives

    Science.gov (United States)

    Aksak, Burak

    Realization of the unique aspects of gecko adhesion and incorporating these aspects into a comprehensive design methodology is essential to enable fabrication of application oriented gecko-inspired dry fibrillar adhesives. To address the need for such a design methodology, we propose a fibrillar adhesion model that evaluates the effect of fiber dimensions and material on adhesive performance of fiber arrays. A fibrillar adhesion model is developed to predict the adhesive characteristics of an array of fibrillar structures, and quantify the effect of fiber length, radius, spacing, and material. Photolithography techniques were utilized to fabricate elastomer microfiber arrays. Fibers that are fabricated from stiff SU-8 photoresist are used to fabricate a flexible negative mold that facilitates fabrication of fiber arrays from various elastomers with high yield. The tips of the cylindrical fibers are modified to mushroom-like tip shapes. Adhesive strengths in excess of 100 kPa is obtained with mushroom tipped elastomer microfibers. Vertically aligned carbon nanofibers (VACNFs) are utilized as enhanced friction materials by partially embedding inside soft polyurethanes. Friction coefficients up to 1 were repeatedly obtained from the resulting VACNF composite structures. A novel fabrication method is used to attach Poly(n-butyl acrylate) (PBA) molecular brush-like structures on the surface of polydimethylsiloxane (PDMS). These brushes are grown on unstructured PDMS and PDMS fibers with mushroom tips. Pull-off force is enhanced by up to 7 times with PBA brush grafted micro-fiber arrays over unstructured PDMS substrate. Adhesion model, initially developed for curved smooth surfaces, is extended to self-affine fractal surfaces to better reflect the adhesion performance of fiber arrays on natural surfaces. Developed adhesion model for fiber arrays is used in an optimization scheme which estimates optimal design parameters to obtain maximum adhesive strength on a given

  16. Gecko-inspired bidirectional double-sided adhesives.

    Science.gov (United States)

    Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

    2014-05-14

    A new concept of gecko-inspired double-sided adhesives (DSAs) is presented. The DSAs, constructed by dual-angled (i.e. angled base and angled tip) micro-pillars on both sides of the backplane substrate, are fabricated by combinations of angled etching, mould replication, tip modification, and curing bonding. Two types of DSA, symmetric and antisymmetric (i.e. pillars are patterned symmetrically or antisymmetrically relative to the backplane), are fabricated and studied in comparison with the single-sided adhesive (SSA) counterparts through both non-conformal and conformal tests. Results indicate that the DSAs show controllable and bidirectional adhesion. Combination of the two pillar-layers can either amplify (for the antisymmetric DSA, providing a remarkable and durable adhesion capacity of 25.8 ± 2.8 N cm⁻² and a high anisotropy ratio of ∼8) or counteract (for the symmetric DSA, generating almost isotropic adhesion) the adhesion capacity and anisotropic level of one SSA (capacity of 16.2 ± 1.7 N cm⁻² and anisotropy ratio of ∼6). We demonstrate that these two DSAs can be utilized as a facile fastener for two individual objects and a small-scale delivery setup, respectively, complementing the functionality of the commonly studied SSA. As such, the double-sided patterning is believed to be a new branch in the further development of biomimetic dry adhesives.

  17. Supramolecular polymer adhesives: advanced materials inspired by nature.

    Science.gov (United States)

    Heinzmann, Christian; Weder, Christoph; de Espinosa, Lucas Montero

    2016-01-21

    Due to their dynamic, stimuli-responsive nature, non-covalent interactions represent versatile design elements that can be found in nature in many molecular processes or materials, where adaptive behavior or reversible connectivity is required. Examples include molecular recognition processes, which trigger biological responses or cell-adhesion to surfaces, and a broad range of animal secreted adhesives with environment-dependent properties. Such advanced functionalities have inspired researchers to employ similar design approaches for the development of synthetic polymers with stimuli-responsive properties. The utilization of non-covalent interactions for the design of adhesives with advanced functionalities such as stimuli responsiveness, bonding and debonding on demand capability, surface selectivity or recyclability is a rapidly emerging subset of this field, which is summarized in this review.

  18. A wet-tolerant adhesive patch inspired by protuberances in suction cups of octopi

    Science.gov (United States)

    Baik, Sangyul; Kim, Da Wan; Park, Youngjin; Lee, Tae-Jin; Ho Bhang, Suk; Pang, Changhyun

    2017-06-01

    Adhesion strategies that rely on mechanical interlocking or molecular attractions between surfaces can suffer when coming into contact with liquids. Thus far, artificial wet and dry adhesives have included hierarchical mushroom-shaped or porous structures that allow suction or capillarity, supramolecular structures comprising nanoparticles, and chemistry-based attractants that use various protein polyelectrolytes. However, it is challenging to develop adhesives that are simple to make and also perform well—and repeatedly—under both wet and dry conditions, while avoiding non-chemical contamination on the adhered surfaces. Here we present an artificial, biologically inspired, reversible wet/dry adhesion system that is based on the dome-like protuberances found in the suction cups of octopi. To mimic the architecture of these protuberances, we use a simple, solution-based, air-trap technique that involves fabricating a patterned structure as a polymeric master, and using it to produce a reversed architecture, without any sophisticated chemical syntheses or surface modifications. The micrometre-scale domes in our artificial adhesive enhance the suction stress. This octopus-inspired system exhibits strong, reversible, highly repeatable adhesion to silicon wafers, glass, and rough skin surfaces under various conditions (dry, moist, under water and under oil). To demonstrate a potential application, we also used our adhesive to transport a large silicon wafer in air and under water without any resulting surface contamination.

  19. Design and fabrication of polymer based dry adhesives inspired by the gecko adhesive system

    Science.gov (United States)

    Jin, Kejia

    There has been significant interest in developing dry adhesives mimicking the gecko adhesive system, which offers several advantages compared to conventional pressure sensitive adhesives. Specifically, gecko adhesive pads have anisotropic adhesion properties: the adhesive pads (spatulae) stick strongly when sheared in one direction but are non-adherent when sheared in the opposite direction. This anisotropy property is attributed to the complex topography of the array of fine tilted and curved columnar structures (setae) that bear the spatulae. In this thesis, easy, scalable methods, relying on conventional and unconventional techniques are presented to incorporate tilt in the fabrication of synthetic polymer-based dry adhesives mimicking the gecko adhesive system, which provide anisotropic adhesion properties. In the first part of the study, the anisotropic adhesion and friction properties of samples with various tilt angles to test the validity of a nanoscale tape-peeling model of spatular function are measured. Consistent with the Peel Zone model, samples with lower tilt angles yielded larger adhesion forces. Contact mechanics of the synthetic array were highly anisotropic, consistent with the frictional adhesion model and gecko-like. Based on the original design, a new design of gecko-like dry adhesives was developed which showed superior tribological properties and furthermore showed anisotropic adhesive properties without the need for tilt in the structures. These adhesives can be used to reversibly suspend weights from vertical surfaces (e.g., walls) and, for the first time to our knowledge, horizontal surfaces (e.g., ceilings) by simultaneously and judiciously activating anisotropic friction and adhesion forces. Furthermore, adhesion properties between artificial gecko-inspired dry adhesives and rough substrates with varying roughness are studied. The results suggest that both adhesion and friction forces on a rough substrate depends significantly on the

  20. A bio-inspired approach for in situ synthesis of tunable adhesive.

    Science.gov (United States)

    Sun, Leming; Yi, Sijia; Wang, Yongzhong; Pan, Kang; Zhong, Qixin; Zhang, Mingjun

    2014-03-01

    Inspired by the strong adhesive produced by English ivy, this paper proposes an in situ synthesis approach for fabricating tunable nanoparticle enhanced adhesives. Special attention was given to tunable features of the adhesive produced by the biological process. Parameters that may be used to tune properties of the adhesive will be proposed. To illustrate and validate the proposed approach, an experimental platform was presented for fabricating tunable chitosan adhesive enhanced by Au nanoparticles synthesized in situ. This study contributes to a bio-inspired approach for in situ synthesis of tunable nanocomposite adhesives by mimicking the natural biological processes of ivy adhesive synthesis.

  1. Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"

    Science.gov (United States)

    Speidel, Matthias W; Kleemeier, Malte; Hartwig, Andreas; Rischka, Klaus; Ellermann, Angelika; Daniels, Rolf

    2017-01-01

    Background: Based on previous chemical analyses of insect tarsal adhesives, we prepared 12 heterogeneous synthetic emulsions mimicking the polar/non-polar principle, analysed their microscopical structure and tested their adhesive, frictional, and rheological properties. Results: The prepared emulsions varied in their consistency from solid rubber-like, over soft elastic, to fluid (watery or oily). With droplet sizes >100 nm, all the emulsions belonged to the common type of macroemulsions. The emulsions of the first generation generally showed broader droplet-size ranges compared with the second generation, especially when less defined components such as petrolatum or waxes were present in the lipophilic fraction of the first generation of emulsions. Some of the prepared emulsions showed a yield point and were Bingham fluids. Tribometric adhesion was tested via probe tack tests. Compared with the "second generation" (containing less viscous components), the "first generation" emulsions were much more adhesive (31–93 mN), a finding attributable to their highly viscous components, i.e., wax, petrolatum, gelatin and poly(vinyl alcohol). In the second generation emulsions, we attained much lower adhesivenesses, ranging between 1–18 mN. The adhesive performance was drastically reduced in the emulsions that contained albumin as the protein component or that lacked protein. Tribometric shear tests were performed at moderate normal loads. Our measured friction forces (4–93 mN in the first and 0.1–5.8 mN in the second generation emulsions) were comparatively low. Differences in shear performance were related to the chemical composition and emulsion structure. Conclusion: By varying their chemical composition, synthetic heterogeneous adhesive emulsions can be adjusted to have diverse consistencies and are able to mimic certain rheological and tribological properties of natural tarsal insect adhesives. PMID:28144564

  2. Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives"

    Directory of Open Access Journals (Sweden)

    Matthias W. Speidel

    2017-01-01

    Full Text Available Background: Based on previous chemical analyses of insect tarsal adhesives, we prepared 12 heterogeneous synthetic emulsions mimicking the polar/non-polar principle, analysed their microscopical structure and tested their adhesive, frictional, and rheological properties.Results: The prepared emulsions varied in their consistency from solid rubber-like, over soft elastic, to fluid (watery or oily. With droplet sizes >100 nm, all the emulsions belonged to the common type of macroemulsions. The emulsions of the first generation generally showed broader droplet-size ranges compared with the second generation, especially when less defined components such as petrolatum or waxes were present in the lipophilic fraction of the first generation of emulsions. Some of the prepared emulsions showed a yield point and were Bingham fluids. Tribometric adhesion was tested via probe tack tests. Compared with the "second generation" (containing less viscous components, the "first generation" emulsions were much more adhesive (31–93 mN, a finding attributable to their highly viscous components, i.e., wax, petrolatum, gelatin and poly(vinyl alcohol. In the second generation emulsions, we attained much lower adhesivenesses, ranging between 1–18 mN. The adhesive performance was drastically reduced in the emulsions that contained albumin as the protein component or that lacked protein. Tribometric shear tests were performed at moderate normal loads. Our measured friction forces (4–93 mN in the first and 0.1–5.8 mN in the second generation emulsions were comparatively low. Differences in shear performance were related to the chemical composition and emulsion structure.Conclusion: By varying their chemical composition, synthetic heterogeneous adhesive emulsions can be adjusted to have diverse consistencies and are able to mimic certain rheological and tribological properties of natural tarsal insect adhesives.

  3. Structural and tribometric characterization of biomimetically inspired synthetic "insect adhesives".

    Science.gov (United States)

    Speidel, Matthias W; Kleemeier, Malte; Hartwig, Andreas; Rischka, Klaus; Ellermann, Angelika; Daniels, Rolf; Betz, Oliver

    2017-01-01

    Background: Based on previous chemical analyses of insect tarsal adhesives, we prepared 12 heterogeneous synthetic emulsions mimicking the polar/non-polar principle, analysed their microscopical structure and tested their adhesive, frictional, and rheological properties. Results: The prepared emulsions varied in their consistency from solid rubber-like, over soft elastic, to fluid (watery or oily). With droplet sizes >100 nm, all the emulsions belonged to the common type of macroemulsions. The emulsions of the first generation generally showed broader droplet-size ranges compared with the second generation, especially when less defined components such as petrolatum or waxes were present in the lipophilic fraction of the first generation of emulsions. Some of the prepared emulsions showed a yield point and were Bingham fluids. Tribometric adhesion was tested via probe tack tests. Compared with the "second generation" (containing less viscous components), the "first generation" emulsions were much more adhesive (31-93 mN), a finding attributable to their highly viscous components, i.e., wax, petrolatum, gelatin and poly(vinyl alcohol). In the second generation emulsions, we attained much lower adhesivenesses, ranging between 1-18 mN. The adhesive performance was drastically reduced in the emulsions that contained albumin as the protein component or that lacked protein. Tribometric shear tests were performed at moderate normal loads. Our measured friction forces (4-93 mN in the first and 0.1-5.8 mN in the second generation emulsions) were comparatively low. Differences in shear performance were related to the chemical composition and emulsion structure. Conclusion: By varying their chemical composition, synthetic heterogeneous adhesive emulsions can be adjusted to have diverse consistencies and are able to mimic certain rheological and tribological properties of natural tarsal insect adhesives.

  4. Soy protein adhesives

    Science.gov (United States)

    Charles R. Frihart

    2010-01-01

    In the quest to manufacture and use building materials that are more environmentally friendly, soy adhesives can be an important component. Trees fix and store carbon dioxide in the atmosphere. After the trees are harvested, machinery converts the wood into strands, which are then bonded together with adhesives to form strandboard, used in constructing long-lasting...

  5. Adhesives from modified soy protein

    Science.gov (United States)

    Sun, Susan [Manhattan, KS; Wang, Donghai [Manhattan, KS; Zhong, Zhikai [Manhattan, KS; Yang, Guang [Shanghai, CN

    2008-08-26

    The present invention provides useful adhesive compositions having similar adhesive properties to conventional UF and PPF resins. The compositions generally include a protein portion and modifying ingredient portion selected from the group consisting of carboxyl-containing compounds, aldehyde-containing compounds, epoxy group-containing compounds, and mixtures thereof. The composition is preferably prepared at a pH level at or near the isoelectric point of the protein. In other preferred forms, the adhesive composition includes a protein portion and a carboxyl-containing group portion.

  6. A direct biocombinatorial strategy toward next generation, mussel-glue inspired saltwater adhesives.

    Science.gov (United States)

    Wilke, Patrick; Helfricht, Nicolas; Mark, Andreas; Papastavrou, Georg; Faivre, Damien; Börner, Hans G

    2014-09-10

    Biological materials exhibit remarkable, purpose-adapted properties that provide a source of inspiration for designing new materials to meet the requirements of future applications. For instance, marine mussels are able to attach to a broad spectrum of hard surfaces under hostile conditions. Controlling wet-adhesion of synthetic macromolecules by analogue processes promises to strongly impact materials sciences by offering advanced coatings, adhesives, and glues. The de novo design of macromolecules to mimic complex aspects of mussel adhesion still constitutes a challenge. Phage display allows material scientists to design specifically interacting molecules with tailored affinity to material surfaces. Here, we report on the integration of enzymatic processing steps into phage display biopanning to expand the biocombinatorial procedure and enable the direct selection of enzymatically activable peptide adhesion domains. Adsorption isotherms and single molecule force spectroscopy show that those de novo peptides mimic complex aspects of bioadhesion, such as enzymatic activation (by tyrosinase), the switchability from weak to strong binders, and adsorption under hostile saltwater conditions. Furthermore, peptide-poly(ethylene oxide) conjugates are synthesized to generate protective coatings, which possess anti-fouling properties and suppress irreversible interactions with blood-plasma protein cocktails. The extended phage display procedure provides a generic way to non-natural peptide adhesion domains, which not only mimic nature but also improve biological sequence sections extractable from mussel-glue proteins. The de novo peptides manage to combine several tasks in a minimal 12-mer sequence and thus pave the way to overcome major challenges of technical wet glues.

  7. Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive exceeds material limits.

    Science.gov (United States)

    Gillies, Andrew G; Fearing, Ronald S

    2011-09-20

    Natural gecko array wearless dynamic friction has recently been reported for 30,000 cycles on a smooth substrate. Following these findings, stiff polymer gecko-inspired synthetic adhesives have been proposed for high-cycle applications such as robot feet. Here we examine the behavior of high-density polyethylene (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of engagement on a glass surface, with a normal preload of less than 40 kPa. We find that fiber arrays maintained 54% of the original shear stress of 300 kPa after 10,000 cycles, despite showing a marked plastic deformation of fiber tips. This deformation could be due to shear-induced plastic creep of the fiber tips from high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a fundamental material limit has been reached for these fiber arrays and that future gecko synthetic adhesive designs must take into account the high adhesive forces generated to avoid damage. Although the synthetic material and natural gecko arrays have a similar elastic modulus, the synthetic material does not show the same wear-free dynamic friction as the gecko.

  8. The Contribution of DOPA to Substrate-Peptide Adhesion and Internal Cohesion of Mussel-Inspired Synthetic Peptide Films.

    Science.gov (United States)

    Anderson, Travers H; Yu, Jing; Estrada, Abril; Hammer, Malte U; Waite, J Herbert; Israelachvili, Jacob N

    2010-12-08

    Mussels use a variety of 3, 4-dihydroxyphenyl-l-alanine (DOPA) rich proteins specifically tailored to adhering to wet surfaces. Synthetic polypeptide analogues of adhesive mussel foot proteins (specifically mfp-3) are used to study the role of DOPA in adhesion. The mussel-inspired peptide is a random copolymer of DOPA and N(5) -(2-hydroxyethyl)-l-glutamine synthesized with DOPA concentrations of 0-27 mol% and molecular weights of 5.9-7.1 kDa. Thin films (3-5 nm thick) of the mussel-inspired peptide are used in the surface forces apparatus (SFA) to measure the force-distance profiles and adhesion and cohesion energies of the films in an acetate buffer. The adhesion energies of the mussel-inspired peptide films to mica and TiO(2) surfaces increase with DOPA concentration. The adhesion energy to mica is 0.09 μJ m(-2) mol(DOPA) (-1) and does not depend on contact time or load. The adhesion energy to TiO(2) is 0.29 μJ m(-2) mol(DOPA) (-1) for short contact times and increases to 0.51 μJ m(-2) mol(DOPA) (-1) for contact times >60 min in a way suggestive of a phase transition within the film. Oxidation of DOPA to the quinone form, either by addition of periodate or by increasing the pH, increases the thickness and reduces the cohesion of the films. Adding thiol containing polymers between the oxidized films recovers some of the cohesion strength. Comparison of the mussel-inspired peptide films to previous studies on mfp-3 thin films show that the strong adhesion and cohesion in mfp-3 films can be attributed to DOPA groups favorably oriented within or at the interface of these films.

  9. Sundew-Inspired Adhesive Hydrogels Combined with Adipose-Derived Stem Cells for Wound Healing.

    Science.gov (United States)

    Sun, Leming; Huang, Yujian; Bian, Zehua; Petrosino, Jennifer; Fan, Zhen; Wang, Yongzhong; Park, Ki Ho; Yue, Tao; Schmidt, Michael; Galster, Scott; Ma, Jianjie; Zhu, Hua; Zhang, Mingjun

    2016-01-27

    The potential to harness the unique physical, chemical, and biological properties of the sundew (Drosera) plant's adhesive hydrogels has long intrigued researchers searching for novel wound-healing applications. However, the ability to collect sufficient quantities of the sundew plant's adhesive hydrogels is problematic and has eclipsed their therapeutic promise. Inspired by these natural hydrogels, we asked if sundew-inspired adhesive hydrogels could overcome the drawbacks associated with natural sundew hydrogels and be used in combination with stem-cell-based therapy to enhance wound-healing therapeutics. Using a bioinspired approach, we synthesized adhesive hydrogels comprised of sodium alginate, gum arabic, and calcium ions to mimic the properties of the natural sundew-derived adhesive hydrogels. We then characterized and showed that these sundew-inspired hydrogels promote wound healing through their superior adhesive strength, nanostructure, and resistance to shearing when compared to other hydrogels in vitro. In vivo, sundew-inspired hydrogels promoted a "suturing" effect to wound sites, which was demonstrated by enhanced wound closure following topical application of the hydrogels. In combination with mouse adipose-derived stem cells (ADSCs) and compared to other therapeutic biomaterials, the sundew-inspired hydrogels demonstrated superior wound-healing capabilities. Collectively, our studies show that sundew-inspired hydrogels contain ideal properties that promote wound healing and suggest that sundew-inspired-ADSCs combination therapy is an efficacious approach for treating wounds without eliciting noticeable toxicity or inflammation.

  10. Gecko-inspired carbon nanotube-based self-cleaning adhesives.

    Science.gov (United States)

    Sethi, Sunny; Ge, Liehui; Ci, Lijie; Ajayan, P M; Dhinojwala, Ali

    2008-03-01

    The design of reversible adhesives requires both stickiness and the ability to remain clean from dust and other contaminants. Inspired by gecko feet, we demonstrate the self-cleaning ability of carbon nanotube-based flexible gecko tapes.

  11. Nanohairs and nanotubes: Efficient structural elements for gecko-inspired artificial dry adhesives

    KAUST Repository

    Jeong, Hoon Eui

    2009-08-01

    An overview of the recent progress in the development of gecko-inspired synthetic dry adhesives is presented, with particular emphasis on two major structural elements of nanohairs and nanotubes. With the advance of nanofabrication techniques, recently developed dry adhesives made of nanohairs and nanotubes show excellent adhesion strength, smart directional adhesion as well as rough surface adaptability by better mimicking gecko foot hairs. After a brief description of the requirements for high-performance artificial dry adhesives, a variety of synthetic adhesives are described based on materials and structural features of the gecko-inspired nanostructures. In addition, current challenges and future directions towards an optimized synthetic dry adhesive are presented. © 2009 Elsevier Ltd. All rights reserved.

  12. Adhesive Contact in Animal: Morphology, Mechanism and Bio-Inspired Application

    Institute of Scientific and Technical Information of China (English)

    Aihong Ji; Longbao Han; Zhendong Dai

    2011-01-01

    Many animals possess adhesive pads on their feet,which are able to attach to various substrates while controlling adhesive forces during locomotion.This review article studies the morphology of adhesive devices in animals,and the physical mechanisms of wet adhesion and dry adhesion.The adhesive pads are either ‘smooth' or densely covered with special adhesive setae.Smooth pads adhere by wet adhesion,which is facilitated by fluid secreted from the pads,whereas hairy pads can adhere by dry adhesion or wet adhesion.Contact area,distance between pad and substrate,viscosity and surface tension of the liquid filling the gap between pad and substrate are the most important factors which determine the wet adhesion.Dry adhesion was found only in hairy pads,which occurs in geckos and spiders.It was demonstrated that van der Waals interaction is the dominant adhesive force in geckos' adhesion.The bio-inspired applications derived from adhesive pads are also reviewed.

  13. Rational design and nanofabrication of gecko-inspired fibrillar adhesives.

    Science.gov (United States)

    Hu, Shihao; Xia, Zhenhai

    2012-08-20

    Gecko feet integrate many intriguing functions such as strong adhesion, easy detachment, and self-cleaning. Mimicking gecko toe pad structure leads to the development of new types of fibrillar adhesives useful for various applications. In this Concept article, in addition to the design of adhesive mimics by replicating gecko geometric features, we show a new trend of rational design by adding other physical, chemical, and biological principles on to the geometric merits, for enhancing robustness, responsive control, and durability. Current challenges and future directions are highlighted in the design and nanofabrication of biomimetic fibrillar adhesives.

  14. Superhydrophobic gecko feet with high adhesive forces towards water and their bio-inspired materials

    Science.gov (United States)

    Liu, Kesong; Du, Jiexing; Wu, Juntao; Jiang, Lei

    2012-01-01

    Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a ``mechanical hand'' to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials.

  15. Staying sticky: contact self-cleaning of gecko-inspired adhesives.

    Science.gov (United States)

    Mengüç, Yigit; Röhrig, Michael; Abusomwan, Uyiosa; Hölscher, Hendrik; Sitti, Metin

    2014-05-01

    The exceptionally adhesive foot of the gecko remains clean in dirty environments by shedding contaminants with each step. Synthetic gecko-inspired adhesives have achieved similar attachment strengths to the gecko on smooth surfaces, but the process of contact self-cleaning has yet to be effectively demonstrated. Here, we present the first gecko-inspired adhesive that has matched both the attachment strength and the contact self-cleaning performance of the gecko's foot on a smooth surface. Contact self-cleaning experiments were performed with three different sizes of mushroom-shaped elastomer microfibres and five different sizes of spherical silica contaminants. Using a load-drag-unload dry contact cleaning process similar to the loads acting on the gecko foot during locomotion, our fully contaminated synthetic gecko adhesives could recover lost adhesion at a rate comparable to that of the gecko. We observed that the relative size of contaminants to the characteristic size of the microfibres in the synthetic adhesive strongly determined how and to what degree the adhesive recovered from contamination. Our approximate model and experimental results show that the dominant mechanism of contact self-cleaning is particle rolling during the drag process. Embedding of particles between adjacent fibres was observed for particles with diameter smaller than the fibre tips, and further studied as a temporary cleaning mechanism. By incorporating contact self-cleaning capabilities, real-world applications of synthetic gecko adhesives, such as reusable tapes, clothing closures and medical adhesives, would become feasible.

  16. Carbon nanotube based gecko inspired self-cleaning adhesives

    Science.gov (United States)

    Sethi, Sunny; Ge, Liehui; Ajayan, Pulickel; Ali, Dhinojwala

    2008-03-01

    Wall climbing organisms like geckos have unique ability to attach to different surfaces without use of any viscoelastic material. The hairy structure found in gecko feet allows them to obtain intimate contact over a large area thus allowing then to adhere using van der Waals interactions. Not only high adhesion, the geometry of the hairs makes gecko feet self cleaning, thus allowing them to walk continuously without worrying about loosing adhesive strength. Such properties if mimicked synthetically could form basis of a new class of materials, which, unlike conventional adhesives would show two contradictory properties, self cleaning and high adhesion. Such materials would form essential component of applications like wall climbing robot. We tried to synthesize such material using micropatterened vertically aligned carbon nanotubes. When dealing with large areas, probability of defects in the structure increase, forming patterns instead of using uniform film of carbon nanotubes helps to inhibit crack propagation, thus gives much higher adhesive strength than a uniform film. When carbon nanotube patterns with optimized aspect ratio are used, both high adhesion and self cleaning properties are observed.

  17. Mussel-mimetic protein-based adhesive hydrogel.

    Science.gov (United States)

    Kim, Bum Jin; Oh, Dongyeop X; Kim, Sangsik; Seo, Jeong Hyun; Hwang, Dong Soo; Masic, Admir; Han, Dong Keun; Cha, Hyung Joon

    2014-05-12

    Hydrogel systems based on cross-linked polymeric materials which could provide both adhesion and cohesion in wet environment have been considered as a promising formulation of tissue adhesives. Inspired by marine mussel adhesion, many researchers have tried to exploit the 3,4-dihydroxyphenylalanine (DOPA) molecule as a cross-linking mediator of synthetic polymer-based hydrogels which is known to be able to achieve cohesive hardening as well as adhesive bonding with diverse surfaces. Beside DOPA residue, composition of other amino acid residues and structure of mussel adhesive proteins (MAPs) have also been considered important elements for mussel adhesion. Herein, we represent a novel protein-based hydrogel system using DOPA-containing recombinant MAP. Gelation can be achieved using both oxdiation-induced DOPA quinone-mediated covalent and Fe(3+)-mediated coordinative noncovalent cross-linking. Fe(3+)-mediated hydrogels show deformable and self-healing viscoelastic behavior in rheological analysis, which is also well-reflected in bulk adhesion strength measurement. Quinone-mediated hydrogel has higher cohesive strength and can provide sufficient gelation time for easier handling. Collectively, our newly developed MAP hydrogel can potentially be used as tissue adhesive and sealant for future applications.

  18. Bio-inspired hierarchical polymer fiber-carbon nanotube adhesives.

    Science.gov (United States)

    Rong, Zhuxia; Zhou, Yanmin; Chen, Bingan; Robertson, John; Federle, Walter; Hofmann, Stephan; Steiner, Ullrich; Goldberg-Oppenheimer, Pola

    2014-03-01

    Hierarchical pillar arrays consisting of micrometer-sized polymer setae covered by carbon nanotubes are engineered to deliver the role of spatulae, mimicking the fibrillar adhesive surfaces of geckos. These biomimetic structures conform well and achieve better attachment to rough surfaces, providing a new platform for a variety of applications.

  19. Biomimetic Bidirectional Switchable Adhesive Inspired by the Gecko

    Science.gov (United States)

    2014-01-01

    addition of tilt to the structures, [ 13–15 ] using carbon nanotubes , [ 16,17 ] introducing angled mushroom tips, [ 18 ] functionalizing the gecko-like sur...come into intimate con- tact with opposing surfaces, which maxi- mizes the attractive weak, short-ranged van der Waals interactions [ 2 ] required...since the discovery that van der Waals interactions, which are always present between surfaces, are predominantly responsible for their adhesion

  20. Reverse adhesion of a gecko-inspired synthetic adhesive switched by an ion-exchange polymer-metal composite actuator.

    Science.gov (United States)

    Guo, Dong-Jie; Liu, Rui; Cheng, Yu; Zhang, Hao; Zhou, Li-Ming; Fang, Shao-Ming; Elliott, Winston Howard; Tan, Wei

    2015-03-11

    Inspired by how geckos abduct, rotate, and adduct their setal foot toes to adhere to different surfaces, we have developed an artificial muscle material called ion-exchange polymer-metal composite (IPMC), which, as a synthetic adhesive, is capable of changing its adhesion properties. The synthetic adhesive was cast from a Si template through a sticky colloid precursor of poly(methylvinylsiloxane) (PMVS). The PMVS array of setal micropillars had a high density of pillars (3.8 × 10(3) pillars/mm(2)) with a mean diameter of 3 μm and a pore thickness of 10 μm. A graphene oxide monolayer containing Ag globular nanoparticles (GO/Ag NPs) with diameters of 5-30 nm was fabricated and doped in an ion-exchanging Nafion membrane to improve its carrier transfer, water-saving, and ion-exchange capabilities, which thus enhanced the electromechanical response of IPMC. After being attached to PMVS micropillars, IPMC was actuated by square wave inputs at 1.0, 1.5, or 2.0 V to bend back and forth, driving the micropillars to actively grip or release the surface. To determine the adhesion of the micropillars, the normal adsorption and desorption forces were measured as the IPMC drives the setal micropillars to grip and release, respectively. Adhesion results demonstrated that the normal adsorption forces were 5.54-, 14.20-, and 23.13-fold higher than the normal desorption forces under 1.0, 1.5, or 2.0 V, respectively. In addition, shear adhesion or friction increased by 98, 219, and 245%, respectively. Our new technique provides advanced design strategies for reversible gecko-inspired synthetic adhesives, which might be used for spiderman-like wall-climbing devices with unprecedented performance.

  1. A Theoretical Characterization of Curvature Controlled Adhesive Properties of Bio-Inspired Membranes

    DEFF Research Database (Denmark)

    Afferante, Luciano; Heepe, Lars; Casdorff, Kirstin

    2016-01-01

    Some biological systems, such as the tree frog, Litoria caerulea, and the bush-cricket, Tettigonia viridissima, have developed the ability to control adhesion by changing the curvature of their pads. Active control systems of adhesion inspired by these biological models can be very attractive...... for the development of devices with controllable adhesive properties. In this paper, we present a theory describing the adhesive behavior of an artificial system consisting of an inflatable membrane clamped to a metallic cylinder and filled with air. In such a system, by controlling the internal pressure acting...... the experiments. The present model might help to achieve a better understanding of the adhesion behavior of biological systems and of the fingertips that, in a broad sense, may be regarded as shell-like structures....

  2. A Theoretical Characterization of Curvature Controlled Adhesive Properties of Bio-Inspired Membranes

    DEFF Research Database (Denmark)

    Afferante, Luciano; Heepe, Lars; Casdorff, Kirstin;

    2016-01-01

    Some biological systems, such as the tree frog, Litoria caerulea, and the bush-cricket, Tettigonia viridissima, have developed the ability to control adhesion by changing the curvature of their pads. Active control systems of adhesion inspired by these biological models can be very attractive...... for the development of devices with controllable adhesive properties. In this paper, we present a theory describing the adhesive behavior of an artificial system consisting of an inflatable membrane clamped to a metallic cylinder and filled with air. In such a system, by controlling the internal pressure acting...... on the membrane, it is possible to modulate the adhesive strength. In particular, an increase of the internal pressure and, hence, the curvature of the membrane, results in a decrease of the pull-off force. Results predicted by the theoretical model are in good agreement with experimental data. The model explains...

  3. Biomimetic superhydrophobic surfaces by combining mussel-inspired adhesion with lotus-inspired coating

    Science.gov (United States)

    Xue, Chao-Hua; Ji, Xue-Qing; Zhang, Jing; Ma, Jian-Zhong; Jia, Shun-Tian

    2015-08-01

    Superhydrophobic surfaces on PET textiles were fabricated by combined bioinspiration from the strong adhesion of marine mussels and the two-scale structure of lotus leaves under mild conditions. Dopamine can spontaneously polymerize in alkaline aqueous solution to form a thin adhesive layer of polydopamine (PDA) wrapping on the micro-scale fibers. The as-formed thin PDA layer worked as a reactive template to generate PDA nanoparticles decorated on the fiber surfaces, imparting the textiles with excellent UV-shielding properties as well as a hierarchical structure similar to the morphology of the lotus leaf. After further modification with perfluorodecyl trichlorosilane, the textiles turned superhydrophobic with a water contact angle higher than 150°. Due to the strong adhesion of PDA to a wide range of materials, the present strategy may be extendable to fabrication of superhydrophobic surfaces on a variety of other substrates.

  4. Biomimetic superhydrophobic surfaces by combining mussel-inspired adhesion with lotus-inspired coating.

    Science.gov (United States)

    Xue, Chao-Hua; Ji, Xue-Qing; Zhang, Jing; Ma, Jian-Zhong; Jia, Shun-Tian

    2015-08-21

    Superhydrophobic surfaces on PET textiles were fabricated by combined bioinspiration from the strong adhesion of marine mussels and the two-scale structure of lotus leaves under mild conditions. Dopamine can spontaneously polymerize in alkaline aqueous solution to form a thin adhesive layer of polydopamine (PDA) wrapping on the micro-scale fibers. The as-formed thin PDA layer worked as a reactive template to generate PDA nanoparticles decorated on the fiber surfaces, imparting the textiles with excellent UV-shielding properties as well as a hierarchical structure similar to the morphology of the lotus leaf. After further modification with perfluorodecyl trichlorosilane, the textiles turned superhydrophobic with a water contact angle higher than 150°. Due to the strong adhesion of PDA to a wide range of materials, the present strategy may be extendable to fabrication of superhydrophobic surfaces on a variety of other substrates.

  5. Chapter 16: Soy Proteins as Wood Adhesives

    Science.gov (United States)

    Charles R. Frihart; Christopher G. Hunt; Michael J. Birkeland

    2014-01-01

    Protein adhesives allowed the development of bonded wood products such as plywood and glulam in the early 20th century. Petrochemical-based adhesives replaced proteins in most wood bonding applications because of lower cost, improved production efficiencies, and enhanced durability. However, several technological and environmental factors have led to a resurgence of...

  6. Biomimetic surface modification of polypropylene by surface chain transfer reaction based on mussel-inspired adhesion technology and thiol chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Zhijun; Zhao, Yang; Sun, Wei; Shi, Suqing, E-mail: shisq@nwu.edu.cn; Gong, Yongkuan

    2016-11-15

    Highlights: • Biomimetic surface modification of PP was successfully conducted by integrating mussel-inspired technology, thiol chemistry and cell outer membranes-like structures. • The resultant biomimetic surface exhibits good interface and surface stability. • The obvious suppression of protein adsorption and platelet adhesion is also achieved. • The residue thoil groups on the surface could be further functionalized. - Abstract: Biomimetic surface modification of polypropylene (PP) is conducted by surface chain transfer reaction based on the mussel-inspired versatile adhesion technology and thiol chemistry, using 2-methacryloyloxyethylphosphorylcholine (MPC) as a hydrophilic monomer mimicking the cell outer membrane structure and 2,2-azobisisobutyronitrile (AIBN) as initiator in ethanol. A layer of polydopamine (PDA) is firstly deposited onto PP surface, which not only offers good interfacial adhesion with PP, but also supplies secondary reaction sites (-NH{sub 2}) to covalently anchor thiol groups onto PP surface. Then the radical chain transfer to surface-bonded thiol groups and surface re-initiated polymerization of MPC lead to the formation of a thin layer of polymer brush (PMPC) with cell outer membrane mimetic structure on PP surface. X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle measurements are used to characterize the PP surfaces before and after modification. The protein adsorption and platelet adhesion experiments are also employed to evaluate the interactions of PP surface with biomolecules. The results show that PMPC is successfully grafted onto PP surface. In comparison with bare PP, the resultant PP-PMPC surface exhibits greatly improved protein and platelet resistance performance, which is the contribution of both increased surface hydrophilicity and zwitterionic structure. More importantly, the residue thiol groups on PP-PMPC surface create a new pathway to further functionalize such

  7. Mussel-Inspired Adhesive and Tough Hydrogel Based on Nanoclay Confined Dopamine Polymerization.

    Science.gov (United States)

    Han, Lu; Lu, Xiong; Liu, Kezhi; Wang, Kefeng; Fang, Liming; Weng, Lu-Tao; Zhang, Hongping; Tang, Youhong; Ren, Fuzeng; Zhao, Cancan; Sun, Guoxing; Liang, Rui; Li, Zongjin

    2017-03-28

    Adhesive hydrogels are attractive biomaterials for various applications, such as electronic skin, wound dressing, and wearable devices. However, fabricating a hydrogel with both adequate adhesiveness and excellent mechanical properties remains a challenge. Inspired by the adhesion mechanism of mussels, we used a two-step process to develop an adhesive and tough polydopamine-clay-polyacrylamide (PDA-clay-PAM) hydrogel. Dopamine was intercalated into clay nanosheets and limitedly oxidized between the layers, resulting in PDA-intercalated clay nanosheets containing free catechol groups. Acrylamide monomers were then added and in situ polymerized to form the hydrogel. Unlike previous single-use adhesive hydrogels, our hydrogel showed repeatable and durable adhesiveness. It adhered directly on human skin without causing an inflammatory response and was easily removed without causing damage. The adhesiveness of this hydrogel was attributed to the presence of enough free catechol groups in the hydrogel, which were created by controlling the oxidation process of the PDA in the confined nanolayers of clay. This mimicked the adhesion mechanism of the mussels, which maintain a high concentration of catechol groups in the confined nanospace of their byssal plaque. The hydrogel also displayed superior toughness, which resulted from nanoreinforcement by clay and PDA-induced cooperative interactions with the hydrogel networks. Moreover, the hydrogel favored cell attachment and proliferation, owning to the high cell affinity of PDA. Rat full-thickness skin defect experiments demonstrated that the hydrogel was an excellent dressing. This free-standing, adhesive, tough, and biocompatible hydrogel may be more convenient for surgical applications than adhesives that involve in situ gelation and extra agents.

  8. Importance of loading and unloading procedures for gecko-inspired controllable adhesives.

    Science.gov (United States)

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2013-08-27

    The importance of loading and unloading procedures has been shown in a variety of different methods for biological dry adhesives, such as the fibers on the feet of the Tokay gecko, but biomimetic dry adhesives have yet to be explored in a similar manner. To date, little work has systematically varied multiple parameters to discern the influence of the testing procedure, and the effect of the approach angle remains uncertain. In this study, a synthetic adhesive is moved in 13 individual approach and retraction angles relative to a flat substrate as well as 9 different shear lengths to discern how loading and unloading procedures influence the preload, adhesion, and shear/friction forces supported. The synthetic adhesive, composed of vertical 10 μm diameter semicircular poly(dimethylsiloxane) fibers, is tested against a 4 mm diameter flat glass puck on a home-built microtribometer using both vertical approach and retraction tests and angled approach and retraction tests. The results show that near maximum adhesion and friction can be obtained for most approach and retraction angles, provided that a sufficient shear length is performed. The results also show that the reaction forces during adhesive placement can be significantly reduced by using specific approach angles, resulting for the vertical fibers in a 38-fold increase in the ratio of adhesion force to preload force, μ', when compared to that when using a vertical approach. These results can be of use to those currently researching gecko-inspired adhesives when designing their testing procedures and control algorithms for climbing and perching robots.

  9. Mechanics of load-drag-unload contact cleaning of gecko-inspired fibrillar adhesives.

    Science.gov (United States)

    Abusomwan, Uyiosa A; Sitti, Metin

    2014-10-14

    Contact self-cleaning of gecko-inspired synthetic adhesives with mushroom-shaped tips has been demonstrated recently using load-drag-unload cleaning procedures similar to that of the natural animal. However, the underlying mechanics of contact cleaning has yet to be fully understood. In this work, we present a detailed experiment of contact self-cleaning that shows that rolling is the dominant mechanism of cleaning for spherical microparticle contaminants, during the load-drag-unload procedure. We also study the effect of dragging rate and normal load on the particle rolling friction. A model of spherical particle rolling on an elastomer fibrillar adhesive interface is developed and agrees well with the experimental results. This study takes us closer to determining design parameters for achieving self-cleaning fibrillar adhesives.

  10. Adhesion switch on a gecko-foot inspired smart nanocupule surface.

    Science.gov (United States)

    Song, Wenlong

    2014-11-21

    A gecko-foot inspired nanocupule surface prepared by an AAO template covering method was composed of poly(N-isopropylacrylamide) and polystyrene blend. Both superhydrophobicity and high adhesion force were exhibited on the PNIPAm/PS film at room temperature. Moreover, by controlling the temperature, the wettability of the film could be switched between 138.1 ± 5.5° and 150.6 ± 1.5°, and the adhesion force could also be correspondingly tuned accurately by temperature. This reversibility in both wettability and adhesion force could be used to construct smart devices for fine selection of water droplets. The proof-of-concept was demonstrated by the selective catching of precise weight controlled water droplets at different temperatures. This work could help us to design new type of devices for blood bioanalysis or lossless drug transportation.

  11. Glycosylated hydroxytryptophan in a mussel adhesive protein from Perna viridis.

    Science.gov (United States)

    Zhao, Hua; Sagert, Jason; Hwang, Dong Soo; Waite, J Herbert

    2009-08-28

    The 3,4-dihydroxyphenyl-l-alanine (Dopa)-containing proteins of mussel byssus play a critical role in wet adhesion and have inspired versatile new synthetic strategies for adhesives and coatings. Apparently, however, not all mussel adhesive proteins are beholden to Dopa chemistry. The cDNA-deduced sequence of Pvfp-1, a highly aromatic and redox active byssal coating protein in the green mussel Perna viridis, suggests that Dopa may be replaced by a post-translational modification of tryptophan. The N-terminal tryptophan-rich domain of Pvfp-1 contains 42 decapeptide repeats with the consensus sequences ATPKPW(1)TAW(2)K and APPPAW(1)TAW(2)K. A small collagen domain (18 Gly-X-Y repeats) is also present. Tandem mass spectrometry of isolated tryptic decapeptides has detected both C(2)-hexosylated tryptophan (W(1)) and C(2)-hexosylated hydroxytryptophan (W(2)), the latter of which is redox active. The UV absorbance spectrum of W(2) is consistent with 7-hydroxytryptophan, which represents an intriguing new theme for bioinspired opportunistic wet adhesion.

  12. Glycosylated Hydroxytryptophan in a Mussel Adhesive Protein from Perna viridis*

    Science.gov (United States)

    Zhao, Hua; Sagert, Jason; Hwang, Dong Soo; Waite, J. Herbert

    2009-01-01

    The 3,4-dihydroxyphenyl-l-alanine (Dopa)-containing proteins of mussel byssus play a critical role in wet adhesion and have inspired versatile new synthetic strategies for adhesives and coatings. Apparently, however, not all mussel adhesive proteins are beholden to Dopa chemistry. The cDNA-deduced sequence of Pvfp-1, a highly aromatic and redox active byssal coating protein in the green mussel Perna viridis, suggests that Dopa may be replaced by a post-translational modification of tryptophan. The N-terminal tryptophan-rich domain of Pvfp-1 contains 42 decapeptide repeats with the consensus sequences ATPKPW1TAW2K and APPPAW1TAW2K. A small collagen domain (18 Gly-X-Y repeats) is also present. Tandem mass spectrometry of isolated tryptic decapeptides has detected both C2-hexosylated tryptophan (W1) and C2-hexosylated hydroxytryptophan (W2), the latter of which is redox active. The UV absorbance spectrum of W2 is consistent with 7-hydroxytryptophan, which represents an intriguing new theme for bioinspired opportunistic wet adhesion. PMID:19584055

  13. Biomimetic surface modification of polypropylene by surface chain transfer reaction based on mussel-inspired adhesion technology and thiol chemistry

    Science.gov (United States)

    Niu, Zhijun; Zhao, Yang; Sun, Wei; Shi, Suqing; Gong, Yongkuan

    2016-11-01

    Biomimetic surface modification of polypropylene (PP) is conducted by surface chain transfer reaction based on the mussel-inspired versatile adhesion technology and thiol chemistry, using 2-methacryloyloxyethylphosphorylcholine (MPC) as a hydrophilic monomer mimicking the cell outer membrane structure and 2,2-azobisisobutyronitrile (AIBN) as initiator in ethanol. A layer of polydopamine (PDA) is firstly deposited onto PP surface, which not only offers good interfacial adhesion with PP, but also supplies secondary reaction sites (-NH2) to covalently anchor thiol groups onto PP surface. Then the radical chain transfer to surface-bonded thiol groups and surface re-initiated polymerization of MPC lead to the formation of a thin layer of polymer brush (PMPC) with cell outer membrane mimetic structure on PP surface. X-ray photoelectron spectrophotometer (XPS), atomic force microscopy (AFM) and water contact angle measurements are used to characterize the PP surfaces before and after modification. The protein adsorption and platelet adhesion experiments are also employed to evaluate the interactions of PP surface with biomolecules. The results show that PMPC is successfully grafted onto PP surface. In comparison with bare PP, the resultant PP-PMPC surface exhibits greatly improved protein and platelet resistance performance, which is the contribution of both increased surface hydrophilicity and zwitterionic structure. More importantly, the residue thiol groups on PP-PMPC surface create a new pathway to further functionalize such zwitterion modified PP surface.

  14. Wood adhesives containing proteins and carbohydrates

    Science.gov (United States)

    In recent years there has been resurgent interest in using biopolymers as sustainable and environmentally friendly ingredients in wood adhesive formulations. Among them, proteins and carbohydrates are the most commonly used. In this chapter, an overview is given of protein-based and carbohydrate-...

  15. Biologically-inspired synthetic dry adhesives for wall-climbing robots

    Science.gov (United States)

    Murphy, Michael P.

    Animals such as insects, spiders, and lizards are capable of clinging to and climbing on a variety of surfaces, from rough stone to smooth silicon. Hairy microscale arrays of structures on their feet conform to surface roughness to create millions of points of contact, creating a large overall contact area. Weak intermolecular forces (van der Waals forces) between each fiber tip and the surface sum to large overall forces due to the high number of contacts. In this work we present the fabrication, characterization, and demonstration of synthetic polyurethane fibrillar adhesives inspired by these animals. Angled polymer micro-fiber arrays are fabricated and characterized. A tip modification technique is presented which enables fabrication of fibers with flat mushroom shaped tips which greatly increase the adhesion of the fibers, up to 5N/cm 2 (normal direction), and with a magnitude within the range of geckos (10 N/cm2) in the shear direction on smooth surfaces. We present a fabrication technique to create fibers with angled flat mushroom-shaped tips which replicate the directional characteristics of geckos, gripping in one direction (within the range of gecko adhesion) and releasing easily in the other. Multilevel hierarchical structures with specialized tips for roughness adaptation are also presented. Fiber hierarchies from the millimeter scale to the sub-micron scale are demonstrated, including three-level fiber fabrication with specialized tips. Hierarchical structures demonstrate up to 5 times the adhesion of an unstructured sample, and requiring up to 10 times the detachment energy. Finally, an agile, wireless, palm-sized wall climbing robot which uses the synthetic fibrillar dry adhesives to climb is presented. Waalbot , named after the van der Waals forces it uses to climb, exploits the attachment and detachment characteristics of the developed dry adhesives, capabilities include climbing smooth surfaces such as glass in any orientation on any surface slope

  16. Adhesive complex coacervate inspired by the sandcastle worm as a sealant for fetoscopic defects

    Science.gov (United States)

    Kaur, Sarbjit

    Inspired by the Sandcastle Worm, biomimetic of the water-borne adhesive was developed by complex coacervation of the synthetic copolyelectrolytes, mimicking the chemistries of the worm glue. The developed underwater adhesive was designed for sealing fetal membranes after fetoscopic surgery in twin-to-twin transfusion syndrome (TTTS) and sealing neural tissue of a fetus in aminiotic sac for spina bifida condition. Complex coacervate with increased bond strength was created by entrapping polyethylene glycol diacrylate (PEG-dA) monomer within the cross-linked coacervate network. Maximum shear bond strength of ~ 1.2 MPa on aluminum substrates was reached. The monomer-filled coacervate had complex flow behavior, thickening at low shear rates and then thinning suddenly with a 16-fold drop in viscosity at shear rates near 6 s-1. The microscale structure of the complex coacervates resembled a three-dimensional porous network of interconnected tubules. This complex coacervate adhesive was used in vitro studies to mimic the uterine wall-fetal membrane interface using a water column with one end and sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. The coacervate adhesive in conjunction with the multiphase adhesive was used to seal the defect. The sealant withstood an additional traction of 12 g for 30-60 minutes and turbulence of the water column without leakage of fluid or slippage. The adhesive is nontoxic when in direct contact with human fetal membranes in an organ culture setting. A stable complex coacervate adhesive for long-term use in TTTS and spina bifida application was developed by methacrylating the copolyelectrolytes. The methacrylated coacervate was crosslinked chemically for TTTS and by photopolymerization for spina bifida. Tunable mechanical properties of the adhesive were achieved by varying the methacrylation of the polymers. Varying the amine to phosphate (A/P) ratio in the coacervate formation

  17. Purification of adhesive proteins from mussels.

    Science.gov (United States)

    Pardo, J; Gutierrez, E; Sáez, C; Brito, M; Burzio, L O

    1990-11-01

    The adhesive polyphenolic proteins from the mussels Mytilus chilensis and Choromytilus chorus have been purified based on their solubility in dilute perchloric acid and on differential precipitation with acetone containing about 0.3 N HCl. The specific activity of the proteins obtained was 0.16 mg of 3,4-dihydroxyphenylalanine per milligram of protein, or higher. The proteins have an apparent molecular weight of about 100,000 and they contain a high proportion of 3,4-dihydroxyphenylalanine, lysine, and proline.

  18. Soy and cottonseed protein blends as wood adhesives

    Science.gov (United States)

    As an environmentally friendlier alternative to adhesives from petroleum feedstock, soy proteins are currently being formulated as wood adhesives. Cottonseed proteins have also been found to provide good adhesive properties. In at least some cases, cottonseed proteins appear to form greater shear ...

  19. Design of structurally distinct proteins using strategies inspired by evolution.

    Science.gov (United States)

    Jacobs, T M; Williams, B; Williams, T; Xu, X; Eletsky, A; Federizon, J F; Szyperski, T; Kuhlman, B

    2016-05-06

    Natural recombination combines pieces of preexisting proteins to create new tertiary structures and functions. We describe a computational protocol, called SEWING, which is inspired by this process and builds new proteins from connected or disconnected pieces of existing structures. Helical proteins designed with SEWING contain structural features absent from other de novo designed proteins and, in some cases, remain folded at more than 100°C. High-resolution structures of the designed proteins CA01 and DA05R1 were solved by x-ray crystallography (2.2 angstrom resolution) and nuclear magnetic resonance, respectively, and there was excellent agreement with the design models. This method provides a new strategy to rapidly create large numbers of diverse and designable protein scaffolds.

  20. Regulation of the elastic modulus of polyurethane microarrays and its influence on gecko-inspired dry adhesion

    Science.gov (United States)

    Li, Ming; Zhao, Aiwu; Jiang, Rui; Wang, Dapeng; Li, Da; Guo, Hongyan; Tao, Wenyu; Gan, Zibao; Zhang, Maofeng

    2011-02-01

    We studied the influence of the elastic modulus on the gecko-inspired dry adhesion by regulating the elastic modulus of bulk polyurethane combined with changing the size of microarrays. Segmented polyurethane (PU) was utilized to fabricate micro arrays by the porous polydimethyl siloxane (PDMS) membrane molding method. The properties of the micro arrays, such as the elastic modulus and adhesion, were investigated by Triboindenter. The study demonstrates that bulk surfaces show the highest elastic modulus, with similar values at around 175 MPa and decreasing the arrays radius causes a significant decrease in E, down to 0.62 MPa. The corresponding adhesion experiments show that decrease of the elastic modulus can enhance the adhesion which is consistent with the recent theoretical models.

  1. Strong underwater adhesives made by self-assembling multi-protein nanofibres.

    Science.gov (United States)

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M; Lu, Timothy K

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m(-2), which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  2. Strong underwater adhesives made by self-assembling multi-protein nanofibres

    Science.gov (United States)

    Zhong, Chao; Gurry, Thomas; Cheng, Allen A.; Downey, Jordan; Deng, Zhengtao; Stultz, Collin M.; Lu, Timothy K.

    2014-10-01

    Many natural underwater adhesives harness hierarchically assembled amyloid nanostructures to achieve strong and robust interfacial adhesion under dynamic and turbulent environments. Despite recent advances, our understanding of the molecular design, self-assembly and structure-function relationships of these natural amyloid fibres remains limited. Thus, designing biomimetic amyloid-based adhesives remains challenging. Here, we report strong and multi-functional underwater adhesives obtained from fusing mussel foot proteins (Mfps) of Mytilus galloprovincialis with CsgA proteins, the major subunit of Escherichia coli amyloid curli fibres. These hybrid molecular materials hierarchically self-assemble into higher-order structures, in which, according to molecular dynamics simulations, disordered adhesive Mfp domains are exposed on the exterior of amyloid cores formed by CsgA. Our fibres have an underwater adhesion energy approaching 20.9 mJ m-2, which is 1.5 times greater than the maximum of bio-inspired and bio-derived protein-based underwater adhesives reported thus far. Moreover, they outperform Mfps or curli fibres taken on their own and exhibit better tolerance to auto-oxidation than Mfps at pH ≥ 7.0.

  3. Mussel inspired protein-mediated surface modification to electrospun fibers and their potential biomedical applications.

    Science.gov (United States)

    Xie, Jingwei; Michael, Praveesuda Lorwattanapongsa; Zhong, Shaoping; Ma, Bing; MacEwan, Matthew R; Lim, Chwee Teck

    2012-04-01

    Mussel inspired proteins have been demonstrated to serve as a versatile biologic adhesive with numerous applications. The present study illustrates the use of such Mussel inspired proteins (polydopamine) in the fabrication of functionalized bio-inspired nanomaterials capable of both improving cell response and sustained delivery of model probes. X-ray photoelectron spectroscopy analysis confirmed the ability of dopamine to polymerize on the surface of plasma-treated, electrospun poly(ε-caprolactone) (PCL) fiber mats to form polydopamine coating. Transmission electron microscopy images demonstrated that self-polymerization of dopamine was induced by pH shift and that the thickness of polydopamine coating was readily modulated by adjusting the concentration of dopamine and reaction time. Polydopamine coatings were noted to affect the mechanical properties of underlying fiber mats, as mechanical testing demonstrated a decrease in elasticity and increase in stiffness of polydopamine-coated fiber mats. Polydopamine coatings were also utilized to effectively immobilize extracellular matrix proteins (i.e., fibronectin) on the surface of polydopamine-coated, electrospun fibers, resulting in enhancement of NIH3T3 cell attachment, spreading, and cytoskeletal development. Comparison of release rates of rhodamine 6G encapsulated in coated and uncoated PCL fibers also confirmed that polydopamine coatings modulate the release rate of loaded payloads. The authors further demonstrate the significant difference of rhodamine 6G adsorption kinetics in water between PCL fibers and polydopamine-coated PCL fibers. Taken together, polydopamine-mediated surface modification to electrospun fibers may be an effective means of fabricating a wide range of bio-inspired nanomaterials with unique properties for use in tissue engineering, drug delivery, and advanced biomedical applications.

  4. Mussel-inspired human gelatin nanocoating for creating biologically adhesive surfaces

    Directory of Open Access Journals (Sweden)

    Yang X

    2014-05-01

    Full Text Available Xi Yang,1,2 Liping Zhu,1 Seiichi Tada,1 Di Zhou,3 Takashi Kitajima,1 Takashi Isoshima,1 Yasuhiro Yoshida,1,4 Mariko Nakamura,1,5 Weiqun Yan,2 Yoshihiro Ito1,3 1Nano Medical Engineering Laboratory, RIKEN, Saitama, Japan; 2School of Pharmaceutical Sciences, Jilin University, Jilin, People’s Republic of China; 3Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, Saitama, 4Department of Biomaterials and Bioengineering, Graduate School of Dental Medicine, Hokkaido University, Hokkaido, 5Dental Hygiene Program, Kibi International College, Okayama, Japan Abstract: Recombinant human gelatin was conjugated with dopamine using carbodiimide as a surface modifier. This dopamine-coupled human gelatin (D-rhG was characterized by 1H-nuclear magnetic resonance, mass spectroscopy, and circular dichroism. D-rhG-coated surface properties were analyzed by physicochemical methods. Additionally, cell attachment and growth on the modified surfaces was assessed using human umbilical endothelial cells. Binding of gelatin onto titanium was significantly enhanced by dopamine conjugation. The thickness of the D-rhG coating depended on the treatment pH; thicker layers were formed at higher pH values, with a maximum thickness of 30 nm. D-rhG enhanced the binding of collagen-binding vascular endothelial growth factor and cell adhesion as compared with gelatin alone, even at the same surface concentration. The D-rhG surface modifier enhanced substrate binding by creating an adhesive nanointerface that increased specific protein binding and cell attachment. Keywords: recombinant human gelatin, dopamine, natural catechols, cell adhesion, cell culture, titanium

  5. Formation, Removal, and Reformation of Surface Coatings on Various Metal Oxide Surfaces Inspired by Mussel Adhesives.

    Science.gov (United States)

    Kang, Taegon; Oh, Dongyeop X; Heo, Jinhwa; Lee, Han-Koo; Choy, Seunghwan; Hawker, Craig J; Hwang, Dong Soo

    2015-11-11

    Mussels survive by strongly attaching to a variety of different surfaces, primarily subsurface rocks composed of metal oxides, through the formation of coordinative interactions driven by protein-based catechol repeating units contained within their adhesive secretions. From a chemistry perspective, catechols are known to form strong and reversible complexes with metal ions or metal oxides, with the binding affinity being dependent on the nature of the metal ion. As a result, catechol binding with metal oxides is reversible and can be broken in the presence of a free metal ion with a higher stability constant. It is proposed to exploit this competitive exchange in the design of a new strategy for the formation, removal, and reformation of surface coatings and self-assembled monolayers (SAM) based on catechols as the adhesive unit. In this study, catechol-functionalized tri(ethylene oxide) (TEO) was synthesized as a removable and recoverable self-assembled monolayer (SAM) for use on oxides surfaces. Attachment and detachment of these catechol derivatives on a variety of surfaces was shown to be reversible and controllable by exploiting the high stability constant of catechol to soluble metal ions, such as Fe(III). This tunable assembly based on catechol binding to metal oxides represents a new concept for reformable coatings with applications in fields ranging from friction/wettability control to biomolecular sensing and antifouling.

  6. Improved Bio-inspired Artificial Gecko Adhesive by Using Hierarchical Fibrillar Structures

    OpenAIRE

    Li, Yasong

    2014-01-01

    Geckos are well known for being rapid climbers that have long existed in nature. The reversible and reusable adhesive on their feet intrigues scientists to explore a bio-mimetic adhesive, which inherits the adhesion properties of the gecko’s adhesives. Recent advances in electron microscopy reveal the secret of gecko’s climbing ability: there are hierarchical fibrillar structures branching from the skin of their climbing feet. Sizes of these hierarchical fibrils range from micrometer to nanom...

  7. Mussel adhesion is dictated by time-regulated secretion and molecular conformation of mussel adhesive proteins

    Science.gov (United States)

    Petrone, Luigi; Kumar, Akshita; Sutanto, Clarinda N.; Patil, Navinkumar J.; Kannan, Srinivasaraghavan; Palaniappan, Alagappan; Amini, Shahrouz; Zappone, Bruno; Verma, Chandra; Miserez, Ali

    2015-10-01

    Interfacial water constitutes a formidable barrier to strong surface bonding, hampering the development of water-resistant synthetic adhesives. Notwithstanding this obstacle, the Asian green mussel Perna viridis attaches firmly to underwater surfaces via a proteinaceous secretion (byssus). Extending beyond the currently known design principles of mussel adhesion, here we elucidate the precise time-regulated secretion of P. viridis mussel adhesive proteins. The vanguard 3,4-dihydroxy-L-phenylalanine (Dopa)-rich protein Pvfp-5 acts as an adhesive primer, overcoming repulsive hydration forces by displacing surface-bound water and generating strong surface adhesion. Using homology modelling and molecular dynamics simulations, we find that all mussel adhesive proteins are largely unordered, with Pvfp-5 adopting a disordered structure and elongated conformation whereby all Dopa residues reside on the protein surface. Time-regulated secretion and structural disorder of mussel adhesive proteins appear essential for optimizing extended nonspecific surface interactions and byssus' assembly. Our findings reveal molecular-scale principles to help the development of wet-resistant adhesives.

  8. Urea modified cottonseed protein adhesive for wood composite products

    Science.gov (United States)

    Cottonseed protein has the potential to be used as renewable and environmentally friendly adhesives in wood products industry. However, the industry application was limited by its low mechanical properties, low water resistance and viscosity. In this work, urea modified cottonseed protein adhesive w...

  9. Investigation of modified cottonseed protein adhesives for wood composites

    Science.gov (United States)

    Several modified cottonseed protein isolates were studied and compared to corresponding soy protein isolates for their adhesive properties when bonded to wood composites. Modifications included treatments with alkali, guanidine hydrochloride, sodium dodecyl sulfate (SDS), and urea. Wood composites...

  10. Caddisfly Inspired Phosphorylated Poly(ester urea)-Based Degradable Bone Adhesives.

    Science.gov (United States)

    Bhagat, Vrushali; O'Brien, Emily; Zhou, Jinjun; Becker, Matthew L

    2016-09-12

    Bone and tissue adhesives are essential in surgeries for wound healing, hemostasis, tissue reconstruction, and drug delivery. However, there are very few degradable materials with high adhesion strengths that degrade into bioresorbable byproducts. Caddisfly adhesive silk is interesting due to the presence of phosphoserines, which are thought to afford adhesive properties. In this work, phosphoserine-valine poly(ester urea) copolymers with 2% and 5% phosphoserine content were synthesized to mimic caddisfly adhesive silk. Significantly, the materials are ethanol soluble and water insoluble, making them clinically relevant. Their physical properties were quantified, and the adhesion properties were studied on aluminum and bovine bone substrates before and after cross-linking with Ca(2+) ions. The adhesive strength of the phosphorylated copolymer on a bone substrate after cross-linking with Ca(2+) was 439 ± 203 kPa, comparable to commercially available PMMA bone cement (530 ± 133 kPa).

  11. Characterization of canine platelet adhesion to extracellular matrix proteins.

    Science.gov (United States)

    Pelagalli, Alessandra; Pero, Maria Elena; Mastellone, Vincenzo; Cestaro, Anna; Signoriello, Simona; Lombardi, Pietro; Avallone, Luigi

    2011-07-01

    Canine platelets have been extensively studied but little is known about specific aspects such as adhesion. Platelet adhesion is a critical step during haemostasis and thrombosis as well as during inflammatory and immunopathogenic responses. The aim of this study was to evaluate the adhesive properties of canine platelets using fibrinogen and collagen as substrates immobilized on plates. Adhesion was monitored for 120 min and the effect of adenosine 5'-diphosphate (ADP) was assayed. The results showed that canine platelets displayed good adhesion activity that was significantly time-dependent. Moreover, ADP was able to enhance platelet adhesion in a dose-dependent manner. The findings aid knowledge of the adhesion process and suggest a specific role of surface platelet receptors in mediating the interaction with extracellular matrix proteins.

  12. Mussel-Inspired Polymer Carpets: Direct Photografting of Polymer Brushes on Polydopamine Nanosheets for Controlled Cell Adhesion.

    Science.gov (United States)

    Hafner, Daniel; Ziegler, Lisa; Ichwan, Muhammad; Zhang, Tao; Schneider, Maximilian; Schiffmann, Michael; Thomas, Claudia; Hinrichs, Karsten; Jordan, Rainer; Amin, Ihsan

    2016-02-17

    2D mussel-inspired polydopamine (PDA) nanosheets are prepared and exploited as a functional surface for grafting various polymer brushes. The PDA nanosheet and its polymer-brush derivatives show lateral integrity and are robust; therefore, they can be detached from their substrates. Cell-adhesion tests show that the PDA nanosheet promotes cell growth and attachment, while a PDA-based poly(3-sulfopropyl methacrylate) carpet exhibits nonfouling behavior. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Bio-Inspired Design and Fabrication of Micro/Nano-Brush Dual Structural Surfaces for Switchable Oil Adhesion and Antifouling.

    Science.gov (United States)

    Du, Tao; Ma, Shuanhong; Pei, Xiaowei; Wang, Shutao; Zhou, Feng

    2017-01-01

    The underwater superoleophobic surfaces play a significant role in anti-oil contamination, marine antifouling, etc. Inspired by the Gecko's feet and its self-cleaning property, a hierarchical structure composed of poly (acrylic acid) gel micro-brushes is designed by the liquid-infused method. This surface exhibits underwater superoleophobicity with very low oil adhesion. It is then modified with stimuli-responsive polymer nano-brushes via surface-initiated atom transfer radical polymerization from the embedded initiator. The micro/nano-brush dual structural surfaces can switch the underwater oil adhesion between low and high while keeping the superoleophobicity. The antifouling properties against algae attachment under different mediums are also investigated to show a strong link between oleophobicity and antibiofouling property. The model surface will be very useful in directing the design of marine self-cleaning coatings to both living and non-living species.

  14. Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    Science.gov (United States)

    Jeong, Hoon Eui; Lee, Jin-Kwan; Kwak, Moon Kyu; Moon, Sang Heup; Suh, Kahp Yang

    2010-01-01

    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0° to 45° and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness.

  15. Soy protein isolate molecular level contributions to bulk adhesive properties

    Science.gov (United States)

    Shera, Jeanne Norton

    Increasing environmental awareness and the recognized health hazards of formaldehyde-based resins has prompted a strong demand for environmentally-responsible adhesives for wood composites. Soy protein-based adhesives have been shown to be commercially viable with 90-day shelf stability and composite physical properties comparable to those of commercial formaldehyde-based particleboards. The main research focus is to isolate and characterize the molecular level features in soy protein isolate responsible for providing mechanical properties, storage stability, and water resistance during adhesive formulation, processing, and wood composite fabrication. Commercial composite board will be reviewed to enhance our understanding of the individual components and processes required for particleboard production. The levels of protein structure will be defined and an overview of current bio-based technology will be presented. In the process, the logic for utilizing soy protein as a sole binder in the adhesive will be reinforced. Variables such as adhesive components, pH, divalent ions, blend aging, protein molecular weight, formulation solids content, and soy protein functionalization will relate the bulk properties of soy protein adhesives to the molecular configuration of the soybean protein. This work has demonstrated that when intermolecular beta-sheet interactions and protein long-range order is disrupted, viscosity and mechanical properties decrease. Storage stability can be maintained through the stabilization of intermolecular beta-sheet interactions. When molecular weight is reduced through enzymatic digestion, long-range order is disrupted and viscosity and mechanical properties decrease accordingly. Processibility and physical properties must be balanced to increase solids while maintaining low viscosity, desirable mechanical properties, and adequate storage stability. The structure of the soybean protein must be related to the particleboard bulk mechanical

  16. Optimized Baxter model of protein solutions: electrostatics versus adhesion

    NARCIS (Netherlands)

    Prinsen, P.; Odijk, T.

    2004-01-01

    A theory is set up of spherical proteins interacting by screened electrostatics and constant adhesion, in which the effective adhesion parameter is optimized by a variational principle for the free energy. An analytical approach to the second virial coefficient is first outlined by balancing the rep

  17. Effect of leaning angle of gecko-inspired slanted polymer nanohairs on dry adhesion

    KAUST Repository

    Jeong, Hoon Eui

    2010-01-01

    We present analysis of adhesion properties of angled polymer nanohairs with a wide range of leaning angles from 0° to 45° and ultraviolet (UV)-curable polyurethane acrylate (PUA) materials of two different elastic moduli (19.8 and 320 MPa). It is demonstrated that shear adhesion and adhesion hysteresis can be greatly enhanced by increasing the leaning angle of nanohairs both for soft and hard materials due to increased contact area and reduced structural stiffness. © 2010 American Institute of Physics.

  18. Spatial distribution of proteins in the quagga mussel adhesive apparatus.

    Science.gov (United States)

    Rees, David J; Hanifi, Arash; Manion, Joseph; Gantayet, Arpita; Sone, Eli D

    2016-01-01

    The invasive freshwater mollusc Dreissena bugensis (quagga mussel) sticks to underwater surfaces via a proteinacious 'anchor' (byssus), consisting of a series of threads linked to adhesive plaques. This adhesion results in the biofouling of crucial underwater industry infrastructure, yet little is known about the proteins responsible for the adhesion. Here the identification of byssal proteins extracted from freshly secreted byssal material is described. Several new byssal proteins were observed by gel electrophoresis. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry was used to characterize proteins in different regions of the byssus, particularly those localized to the adhesive interface. Byssal plaques and threads contain in common a range of low molecular weight proteins, while several proteins with higher mass were observed only in the plaque. At the adhesive interface, a plaque-specific ~8.1 kDa protein had a relative increase in signal intensity compared to the bulk of the plaque, suggesting it may play a direct role in adhesion.

  19. Prediction of the adhesive behavior of bio-inspired functionally graded materials against rough surfaces

    Directory of Open Access Journals (Sweden)

    Chen Peijian

    2014-06-01

    Full Text Available Roughness effect and adhesion properties are important characteristics to be accessed in the development of functionally graded materials for biological and biomimetic applications, particularly for the hierarchical composition in biomimetic gecko robot. A multi-asperities adhesion model to predict the adhesive forces is presented in this work. The effect of surface roughness and graded material properties, which significantly alter the adhesive strength between contact bodies, can be simultaneously considered in the generalized model. It is found that proper interfacial strength can be controlled by adjusting surface roughness σ / R, graded exponent k and material parameter E*R / Δγ. The results should be helpful in the design of new biomimetic materials and useful in application of micro functional instruments.

  20. Glue from the Sea:Biomedical Adhesives Inspired by Algal Polymers

    Institute of Scientific and Technical Information of China (English)

    H.Bianco-Peled; R.Bitton; P.Potin

    2007-01-01

    1 Introduction Tissue repair following surgery or trauma has been dominated by sutures,staples and wiring.Although these techniques are well established and widely used,their application often involves pain,unaesthetic results,or bleeding. These limitations emphasize the need for adhesive products to be available to surgeons.2 ResultsA challenging aspect of developing new tissue adhesive is to create a material that can glue wet surfaces.The success of synthetic glues under such an environment is very ...

  1. Nanoscale adhesion, friction and wear of proteins on polystyrene.

    Science.gov (United States)

    Bhushan, Bharat; Utter, Jason

    2013-02-01

    Protein layers are routinely deployed on biomaterials and biological micro/nanoelectromechanical systems (bioMEMS/NEMS) as a functional layer allowing for specific molecular recognition, binding properties or to facilitate biocompatibility. In addition, uncoated biomaterial surfaces will have uncontrolled protein layers adsorbing to the surface within seconds of implantation, so a pre-defined protein layer will improve the host response. Implanted biomaterials also experience micromotion over time which may degrade any surface protein layers. Degradation of these protein layers may lead to system failure or an unwanted immune response. Therefore, it is important to characterize the interfacial properties of proteins on biomaterial surfaces. In this study, the nanoscale adhesion, friction and wear properties of proteins adsorbed to a spin coated polystyrene surface were measured using atomic force microscopy (AFM) in deionized (DI) water and phosphate buffered saline. Adhesion, friction and wear have been measured for bovine serum albumin (BSA), collagen, fibronectin and streptavidin (STA) in DI water and PBS as a function of protein concentration. These proteins were chosen due to their importance and widespread application in the biotechnology field. Adhesion and friction were also measured for BSA and STA at two different temperatures and different pH values to simulate a biological environment. Based on this study, adhesion, friction and wear mechanisms of the different proteins are discussed.

  2. An experimental study on adhesive or antiadhesiveand strong bio-inspired nanomaterials

    OpenAIRE

    Lepore, Emiliano

    2012-01-01

    This experimental PhD thesis presents the results of research performed in five different facilities: in the Laboratory of Bio-inspired Nanomechanics "Giuseppe Maria Pugno" at the Politecnico of Torino, the "Nanofacility Piemonte" at the INRIM Institute in Torino, the Division of Dental Sciences and Biomaterials of the Department of Biomedicine at the University of Trieste, the Physics Department of the Politecnico of Torino, the Toscano- Buono Veterinary Surgery in Torino and the Department ...

  3. Nanoscale adhesion forces between enamel pellicle proteins and hydroxyapatite.

    Science.gov (United States)

    Vukosavljevic, D; Hutter, J L; Helmerhorst, E J; Xiao, Y; Custodio, W; Zaidan, F C; Oppenheim, F G; Siqueira, W L

    2014-05-01

    The acquired enamel pellicle (AEP) is important for minimizing the abrasion caused by parafunctional conditions as they occur, for instance, during bruxism. It is a remarkable feature of the AEP that a protein/peptide film can provide enough protection in normofunction to prevent teeth from abrasion and wear. Despite its obvious critical role in the protection of tooth surfaces, the essential adhesion features of AEP proteins on the enamel surface are poorly characterized. The objective of this study was to measure the adhesion force between histatin 5, a primary AEP component, and hydroxyapatite (HA) surfaces. Both biotinylated histatin 5 and biotinylated human serum albumin were allowed to adsorb to streptavidin-coated silica microspheres attached to atomic force microscope (AFM) cantilevers. A multimode AFM with a Nanoscope IIIa controller was used to measure the adhesion force between protein-functionalized silica microspheres attached to cantilever tips and the HA surface. The imaging was performed in tapping mode with a Si3N4 AFM cantilever, while the adhesion forces were measured in AFM contact mode. A collection of force-distance curves (~3,000/replicate) was obtained to generate histograms from which the adhesion forces between histatin 5 or albumin and the HA surface were measured. We found that histatin 5 exhibited stronger adhesion forces (90% >1.830 nN) to the HA surface than did albumin (90% > 0.282 nN). This study presents an objective approach to adhesion force measurements between histatin 5 and HA, and provides the experimental basis for measuring the same parameters for other AEP constituents. Such knowledge will help in the design of synthetic proteins and peptides with preventive and therapeutic benefits for tooth enamel.

  4. Regulation of embryonic cell adhesion by the prion protein.

    Directory of Open Access Journals (Sweden)

    Edward Málaga-Trillo

    2009-03-01

    Full Text Available Prion proteins (PrPs are key players in fatal neurodegenerative disorders, yet their physiological functions remain unclear, as PrP knockout mice develop rather normally. We report a strong PrP loss-of-function phenotype in zebrafish embryos, characterized by the loss of embryonic cell adhesion and arrested gastrulation. Zebrafish and mouse PrP mRNAs can partially rescue this knockdown phenotype, indicating conserved PrP functions. Using zebrafish, mouse, and Drosophila cells, we show that PrP: (1 mediates Ca(+2-independent homophilic cell adhesion and signaling; and (2 modulates Ca(+2-dependent cell adhesion by regulating the delivery of E-cadherin to the plasma membrane. In vivo time-lapse analyses reveal that the arrested gastrulation in PrP knockdown embryos is due to deficient morphogenetic cell movements, which rely on E-cadherin-based adhesion. Cell-transplantation experiments indicate that the regulation of embryonic cell adhesion by PrP is cell-autonomous. Moreover, we find that the local accumulation of PrP at cell contact sites is concomitant with the activation of Src-related kinases, the recruitment of reggie/flotillin microdomains, and the reorganization of the actin cytoskeleton, consistent with a role of PrP in the modulation of cell adhesion via signaling. Altogether, our data uncover evolutionarily conserved roles of PrP in cell communication, which ultimately impinge on the stability of adherens cell junctions during embryonic development.

  5. The MRL proteins: adapting cell adhesion, migration and growth.

    Science.gov (United States)

    Coló, Georgina P; Lafuente, Esther M; Teixidó, Joaquin

    2012-01-01

    MIG-10, RIAM and Lamellipodin (Lpd) are the founding members of the MRL family of multi-adaptor molecules. These proteins have common domain structures but display distinct functions in cell migration and adhesion, signaling, and in cell growth. The binding of RIAM with active Rap1 and with talin provides these MRL molecules with important regulatory roles on integrin-mediated cell adhesion and migration. Furthermore, RIAM and Lpd can regulate actin dynamics through their binding to actin regulatory Ena/VASP proteins. Recent data generated with the Drosophila MRL ortholog called Pico and with RIAM in melanoma cells indicate that these proteins can also regulate cell growth. As MRL proteins represent a relatively new family, many questions on their structure-function relationships remain unanswered, including regulation of their expression, post-translational modifications, new interactions, involvement in signaling and their knockout mice phenotype.

  6. Nanospherical arabinogalactan proteins are a key component of the high-strength adhesive secreted by English ivy

    Science.gov (United States)

    Huang, Yujian; Wang, Yongzhong; Tan, Li; Sun, Leming; Petrosino, Jennifer; Cui, Mei-Zhen; Hao, Feng; Zhang, Mingjun

    2016-06-01

    Over 130 y have passed since Charles Darwin first discovered that the adventitious roots of English ivy (Hedera helix) exude a yellowish mucilage that promotes the capacity of this plant to climb vertical surfaces. Unfortunately, little progress has been made in elucidating the adhesion mechanisms underlying this high-strength adhesive. In the previous studies, spherical nanoparticles were observed in the viscous exudate. Here we show that these nanoparticles are predominantly composed of arabinogalactan proteins (AGPs), a superfamily of hydroxyproline-rich glycoproteins present in the extracellular spaces of plant cells. The spheroidal shape of the AGP-rich ivy nanoparticles results in a low viscosity of the ivy adhesive, and thus a favorable wetting behavior on the surface of substrates. Meanwhile, calcium-driven electrostatic interactions among carboxyl groups of the AGPs and the pectic acids give rise to the cross-linking of the exuded adhesive substances, favor subsequent curing (hardening) via formation of an adhesive film, and eventually promote the generation of mechanical interlocking between the adventitious roots of English ivy and the surface of substrates. Inspired by these molecular events, a reconstructed ivy-mimetic adhesive composite was developed by integrating purified AGP-rich ivy nanoparticles with pectic polysaccharides and calcium ions. Information gained from the subsequent tensile tests, in turn, substantiated the proposed adhesion mechanisms underlying the ivy-derived adhesive. Given that AGPs and pectic polysaccharides are also observed in bioadhesives exuded by other climbing plants, the adhesion mechanisms revealed by English ivy may forward the progress toward understanding the general principles underlying diverse botanic adhesives.

  7. Nanospherical arabinogalactan proteins are a key component of the high-strength adhesive secreted by English ivy.

    Science.gov (United States)

    Huang, Yujian; Wang, Yongzhong; Tan, Li; Sun, Leming; Petrosino, Jennifer; Cui, Mei-Zhen; Hao, Feng; Zhang, Mingjun

    2016-06-07

    Over 130 y have passed since Charles Darwin first discovered that the adventitious roots of English ivy (Hedera helix) exude a yellowish mucilage that promotes the capacity of this plant to climb vertical surfaces. Unfortunately, little progress has been made in elucidating the adhesion mechanisms underlying this high-strength adhesive. In the previous studies, spherical nanoparticles were observed in the viscous exudate. Here we show that these nanoparticles are predominantly composed of arabinogalactan proteins (AGPs), a superfamily of hydroxyproline-rich glycoproteins present in the extracellular spaces of plant cells. The spheroidal shape of the AGP-rich ivy nanoparticles results in a low viscosity of the ivy adhesive, and thus a favorable wetting behavior on the surface of substrates. Meanwhile, calcium-driven electrostatic interactions among carboxyl groups of the AGPs and the pectic acids give rise to the cross-linking of the exuded adhesive substances, favor subsequent curing (hardening) via formation of an adhesive film, and eventually promote the generation of mechanical interlocking between the adventitious roots of English ivy and the surface of substrates. Inspired by these molecular events, a reconstructed ivy-mimetic adhesive composite was developed by integrating purified AGP-rich ivy nanoparticles with pectic polysaccharides and calcium ions. Information gained from the subsequent tensile tests, in turn, substantiated the proposed adhesion mechanisms underlying the ivy-derived adhesive. Given that AGPs and pectic polysaccharides are also observed in bioadhesives exuded by other climbing plants, the adhesion mechanisms revealed by English ivy may forward the progress toward understanding the general principles underlying diverse botanic adhesives.

  8. Recovery property of double-network hydrogel containing mussel-inspired adhesive moiety and nano-silicate.

    Science.gov (United States)

    Liu, Yuan; Lee, Bruce P

    2016-10-28

    Altough double network (DN) hydrogels are extremly tough, they are irreversibly softened during large strain deformation. We incorporated mussel-inspired adhesive moiety, catechol, and a synthetic nano-silicate, Laponite, into DN to examine the effect of strong, reversible crosslinks on the DN's ability to recover its mechanical properties during successive loading cycles. The introduction of catechol and Laponite drastically increased the compressive strength and toughness of DN without compromising the compliance of the hydrogel. After 2 hours of recovery at room temperature, the nanocomposite DN hydrogel recovered over 95 and 82 % of its strain energy and hysteresis, respectively, during successive compressive loading to a strain of 0.5. Both equilibrium swelling and oscillatory rheometry data confirmed that there were minimal changes to the network crosslinking density and stiffness after large strain compressive deformation, indicating that mechanical loading did not result in irreversible structural damage. Strong catechol-Laponite interactions can be repeatedly broken and reform to dissipate fracture energy and enable the recovery of DN hydrogel.

  9. Protein kinase C involvement in focal adhesion formation

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1992-01-01

    Matrix molecules such as fibronectin can promote cell attachment, spreading and focal adhesion formation. Although some interactions of fibronectin with cell surface receptors have now been identified, the consequent activation of intracellular messenger systems by cell/matrix interactions have...... still to be elucidated. We show here that the kinase inhibitors H7 and HA1004 reduce focal adhesion and stress fiber formation in response to fibronectin in a dose-dependent manner, and that activators of protein kinase C can promote their formation under conditions where they do not normally form....... Fibroblasts spread within 1h on substrata composed of fibronectin and formed focal adhesions by 3h, as monitored by interference reflection microscopy (IRM) and by labeling for talin, vinculin and integrin beta 1 subunits. In addition, stress fibers were visible. When cells were allowed to spread for 1h...

  10. Hydrogels of collagen-inspired telechelic triblock copolymers for the sustained release of proteins

    NARCIS (Netherlands)

    Teles, H.M.; Vermonden, T.; Eggink, G.

    2010-01-01

    We studied the release of entrapped protein from transient gels made of thermosensitive, collagen-inspired ABA triblock copolymers with tailorable properties and with mid blocks of two different lengths (~ 37 kDa and ~ 73 kDa). These polymers were produced as heterologous proteins in recombinant yea

  11. Rho family proteins in cell adhesion and cell migration.

    Science.gov (United States)

    Evers, E E; Zondag, G C; Malliri, A; Price, L S; ten Klooster, J P; van der Kammen, R A; Collard, J G

    2000-06-01

    Cell migration and the regulation of cadherin-mediated homotypic cell-cell interactions are critical events during development, morphogenesis and wound healing. Aberrations in signalling pathways involved in the regulation of cell migration and cadherin-mediated cell-cell adhesion contribute to tumour invasion and metastasis. The rho family proteins, including cdc42, rac1 and rhoA, regulate signalling pathways that mediate the distinct actin cytoskeleton changes required for both cellular motility and cell-cell adhesion. Recent studies indicate that rac directly influences rho activity at the GTPase level and that the reciprocal balance between rac and rho activity can determine epithelial or mesenchymal cell morphology and migratory behaviour of epithelial (tumour) cells.

  12. Syntenin-1 and ezrin proteins link activated leukocyte cell adhesion molecule to the actin cytoskeleton

    NARCIS (Netherlands)

    Tudor, C.; Riet, J. te; Eich, C.; Harkes, R.; Smisdom, N.; Bouhuijzen-Wenger, J.; Ameloot, M.; Holt, M.; Kanger, J.S.; Figdor, C.G.; Cambi, A.; Subramaniam, V.

    2014-01-01

    Activated leukocyte cell adhesion molecule (ALCAM) is a type I transmembrane protein member of the immunoglobulin superfamily of cell adhesion molecules. Involved in important pathophysiological processes such as the immune response, cancer metastasis, and neuronal development, ALCAM undergoes both

  13. Anti-proteolytic property and bonding durability of mussel adhesive protein-modified dentin adhesive interface.

    Science.gov (United States)

    Fang, Hui; Li, Quan-Li; Han, Min; Mei, May Lei; Chu, Chun Hung

    2017-10-01

    To evaluate the effect of mussel adhesive protein (MAP) on collagenase activity, dentin collagen degradation and microtensile dentin bond strength (μTBS). Three groups were designed: 1. experimental group: treated with MAP; 2. positive control: treated with GM6001 (collagenase-inhibitor); 3. negative control: treated with distilled water (DW). For collagenase activity, Clostridiopeptidase-A was added to each group (n=5), and collagenase activity was assessed by colorimetric assay. For dentin collagen degradation, thirty dentin slabs were allocated to the three above groups (n=10). Dentin collagen degradation was evaluated by measuring released hydroxyproline by colorimetric assay after being incubated in Clostridiopeptidase-A for 7 days. For microtensile bond strength, sixty human third molars with flat dentin surfaces were etched by phosphoric acid and then assigned to the three above groups (n=20). An etch-and-rinse adhesive system was applied to all three groups as stated in standard clinic protocol. The test of μTBS was performed before and after thermocycling and collagenase challenge. The collagenase activities (nmol/min/mg) in the group of MAP was significantly less inactive compared to the group of GM6001 and DW (MAP0.06), the value of μTBSs after thermocycling and collagenase challenge was significantly greater in the group of MAP and GM6001 compared to the group of DW (MAP, GM6000>DW, pcomposite restoration over time. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  14. Use of additives to enhance the properties of cottonseed protein as wood adhesives

    Science.gov (United States)

    Soy protein is currently being used commercially as a “green” wood adhesive. Previous work in this laboratory has shown that cottonseed protein isolate, tested on maple wood veneer, produced higher adhesive strength and hot water resistance relative to soy protein. In the present study, cottonseed...

  15. Focal adhesion protein abnormalities in myelodysplastic mesenchymal stromal cells

    Energy Technology Data Exchange (ETDEWEB)

    Aanei, Carmen Mariana, E-mail: caanei@yahoo.com [Laboratoire Hematologie, CHU de Saint-Etienne, 42055, Saint-Etienne (France); Department of Immunology, Gr. T. Popa University of Medicine and Pharmacy, 700115, Iasi (Romania); Eloae, Florin Zugun [Department of Immunology, Gr. T. Popa University of Medicine and Pharmacy, 700115, Iasi (Romania); Flandrin-Gresta, Pascale [Laboratoire Hematologie, CHU de Saint-Etienne, 42055, Saint-Etienne (France); CNRS UMR 5239, Universite de Lyon, 42023, Saint-Etienne (France); Tavernier, Emmanuelle [Service Hematologie Clinique, Institut de Cancerologie de la Loire, 42270, Saint-Priest-en-Jarez (France); CNRS UMR 5239, Universite de Lyon, 42023, Saint-Etienne (France); Carasevici, Eugen [Department of Immunology, Gr. T. Popa University of Medicine and Pharmacy, 700115, Iasi (Romania); Guyotat, Denis [Service Hematologie Clinique, Institut de Cancerologie de la Loire, 42270, Saint-Priest-en-Jarez (France); CNRS UMR 5239, Universite de Lyon, 42023, Saint-Etienne (France); Campos, Lydia [Laboratoire Hematologie, CHU de Saint-Etienne, 42055, Saint-Etienne (France); CNRS UMR 5239, Universite de Lyon, 42023, Saint-Etienne (France)

    2011-11-01

    Direct cell-cell contact between haematopoietic progenitor cells (HPCs) and their cellular microenvironment is essential to maintain 'stemness'. In cancer biology, focal adhesion (FA) proteins are involved in survival signal transduction in a wide variety of human tumours. To define the role of FA proteins in the haematopoietic microenvironment of myelodysplastic syndromes (MDS), CD73-positive mesenchymal stromal cells (MSCs) were immunostained for paxillin, pFAK [Y{sup 397}], and HSP90{alpha}/{beta} and p130CAS, and analysed for reactivity, intensity and cellular localisation. Immunofluorescence microscopy allowed us to identify qualitative and quantitative differences, and subcellular localisation analysis revealed that in pathological MSCs, paxillin, pFAK [Y{sup 397}], and HSP90{alpha}/{beta} formed nuclear molecular complexes. Increased expression of paxillin, pFAK [Y{sup 397}], and HSP90{alpha}/{beta} and enhanced nuclear co-localisation of these proteins correlated with a consistent proliferative advantage in MSCs from patients with refractory anaemia with excess blasts (RAEB) and negatively impacted clonogenicity of HPCs. These results suggest that signalling via FA proteins could be implicated in HPC-MSC interactions. Further, because FAK is an HSP90{alpha}/{beta} client protein, these results suggest the utility of HSP90{alpha}/{beta} inhibition as a target for adjuvant therapy for myelodysplasia.

  16. Affixing plant sections without protein based adhesives for protease histochemistry.

    Science.gov (United States)

    Jona, R; Griglione, R

    1999-01-01

    To submit a section of plant tissue to histochemical analysis using protease, the protein based adhesives which keep the slices attached to the slides must be replaced because they are attacked by the enzyme and the slices are washed off the slides. We devised a method to keep the slices attached to the slides during histochemical extractions and subsequent staining. Slides are frosted on two lateral zones by spreading on them a fluoride paste composed of 15 g barium sulfate, 15 g ammonium difluoride, 8 g oxalic acid, 40 ml glycerine and 12 ml deionized water using a thin paint brush. After removing the paste with tap water and drying the slides, the sections are placed on the central clear zone of the slide and covered with an ethyl-cellulose film that keeps the slices in place and allows the reagents to act through it. To do this, the slides are dipped into 0.5% ethyl cellulose (ETC) prepared in a 4:1 mixture of toluene and absolute ethanol. The ETC coating is layered three times to improve its firmness and its ability to retain the slices on the slides. To obtain perfect adhesion, the slide should be oven dried (40-50 C for 10-15 min) to remove any trace of humidity before applying each layer of ETC. Subsequently the sections can be extracted and stained without undue loss of material.

  17. Improvement of interfacial interactions using natural polyphenol-inspired tannic acid-coated nanoclay enhancement of soy protein isolate biofilms

    Science.gov (United States)

    Wang, Zhong; Kang, Haijiao; Zhang, Wei; Zhang, Shifeng; Li, Jianzhang

    2017-04-01

    In this study, a novel and economic surface modification technique for montmorillonite (MMT) nanosheets, a biocompatible coupling cross-linking agent, was developed on an attempt at improving the interfacial adhesion with soy protein isolate (SPI) matrix. Inspired by natural polyphenol, the "green dip-coating" method using tannic acid (TA) to surface-modify MMT (TA@MMT). SPI nanocomposite films modified with MMT or TA@MMT, as well as the control ones, were prepared via the casting method. The TA layer was successfully coated on the MMT surface through the (FeIII) ions coordination chemistry and the synthetic samples were characterized by the Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The compatibility and interfacial interactions between modified MMT and SPI matrix were greatly enhanced by the TA-FeIII coating on the MMT surface. The mechanical properties, water resistance, and thermal stability of the resultant biofilm were increased accordingly. Compared with that of the unmodified SPI film, the tensile strength of the nanocomposite films modified by the green dip-coating was increased by 113.3%. These SPI-based nanocomposite films showed the favorable potential in terms of food packing applications due to their efficient barriers to water vapor and UV and/or visible light.

  18. Dissecting signaling and functions of adhesion G protein-coupled receptors

    DEFF Research Database (Denmark)

    Araç, Demet; Aust, Gabriela; Calebiro, Davide;

    2012-01-01

    G protein-coupled receptors (GPCRs) comprise an expanded superfamily of receptors in the human genome. Adhesion class G protein-coupled receptors (adhesion-GPCRs) form the second largest class of GPCRs. Despite the abundance, size, molecular structure, and functions in facilitating cell and matrix...

  19. Bio-inspired enhancement of friction and adhesion at the polydimethylsiloxane-intestine interface and biocompatibility characterization.

    Science.gov (United States)

    Zhang, Hongyu; Wang, Yi; Vasilescu, Steven; Gu, Zhibin; Sun, Tao

    2017-05-01

    An active navigation of self-propelled miniaturized robot along the intestinal tract without injuring the soft tissue remains a challenge as yet. Particularly in this case an effective control of the interfacial friction and adhesion between the material used and the soft tissue is crucial. In the present study, we investigated the frictional and adhesive properties between polydimethylsiloxane (PDMS, microscopically patterned with micro-pillar arrays and non-patterned with a flat surface) and rabbit small intestinal tract using a universal material tester. The friction coefficient-time plot and adhesive force-time plot were recorded during the friction test (sliding speed: 0.25mm/s; normal loading: 0.4N) and adhesion test (preloading: 0.5N; hoisting speed: 2.5×10(-3)mm/s). In addition, biocompatibility of the PDMS samples was characterized in terms of cell morphology (scanning electron microscope) and cell cytotoxicity (alamarBlue assay) using human vascular endothelial cells (HUVECs). The results demonstrated that the interfacial friction (0.27 vs 0.19) and adhesion (34.9mN vs 26.7mN) were greatly increased using microscopically patterned PDMS, in comparison with non-patterned PDMS. HUVECs adhered to and proliferated on non-patterned/microscopically patterned PDMS very well, with a relative cell viability of about 90% following seeding at 1d, 3d, and 5d. The favorable enhancement of the frictional and adhesive properties, along with the excellent biocompatibility of the microscopically patterned PDMS, makes it a propitious choice for clinical application of self-propelled miniaturized robots. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Adhesion protein networks reveal functions proximal and distal to cell-matrix contacts.

    Science.gov (United States)

    Byron, Adam; Frame, Margaret C

    2016-04-01

    Cell adhesion to the extracellular matrix is generally mediated by integrin receptors, which bind to intracellular adhesion proteins that form multi-molecular scaffolding and signalling complexes. The networks of proteins, and their interactions, are dynamic, mechanosensitive and extremely complex. Recent efforts to characterise adhesions using a variety of technologies, including imaging, proteomics and bioinformatics, have provided new insights into their composition, organisation and how they are regulated, and have also begun to reveal unexpected roles for so-called adhesion proteins in other cellular compartments (for example, the nucleus or centrosomes) in diseases such as cancer. We believe this is opening a new chapter on understanding the wider functions of adhesion proteins, both proximal and distal to cell-matrix contacts.

  1. Aberrant Glycosylation of Plasma Proteins in Severe Preeclampsia Promotes Monocyte Adhesion

    Science.gov (United States)

    Kazanjian, Avedis A.; Tinnemore, Deborah; Gafken, Philip R.; Ogata, Yuko; Napolitano, Peter G.; Stallings, Jonathan D.; Ippolito, Danielle L.

    2014-01-01

    Glycosylation of plasma proteins increases during pregnancy. Our objectives were to investigate an anti-inflammatory role of these proteins in normal pregnancies and determine whether aberrant protein glycosylation promotes monocyte adhesion in preeclampsia. Plasma was prospectively collected from nonpregnant controls and nulliparous patients in all 3 trimesters. Patients were divided into cohorts based on the applicable postpartum diagnosis. U937 monocytes were preconditioned with enzymatically deglycosylated plasma, and monocyte adhesion to endothelial cell monolayers was quantified by spectrophotometry. Plasma from nonpregnant controls, first trimester normotensives, and first trimester patients with mild preeclampsia inhibited monocyte–endothelial cell adhesion (P < .05), but plasma from first trimester patients with severe preeclampsia and second and third trimester normotensives did not. Deglycosylating plasma proteins significantly increased adhesion in all the cohorts. These results support a role of plasma glycoprotein interaction in monocyte–endothelial cell adhesion and could suggest a novel therapeutic target for severe preeclampsia. PMID:23757314

  2. Molecular architecture of a complex between an adhesion protein from the malaria parasite and intracellular adhesion molecule 1

    DEFF Research Database (Denmark)

    Brown, Alan; Turner, Louise; Christoffersen, Stig

    2013-01-01

    . The PfEMP1 family of adhesive proteins is responsible for this sequestration by mediating interactions with diverse human ligands. In addition, as the primary targets of acquired, protective immunity, the PfEMP1s are potential vaccine candidates. PfEMP1s contain large extracellular ectodomains made from......, intercellular adhesion molecule-1 (ICAM-1). We show through small angle x-ray scattering that IT4VAR13 is rigid, elongated, and monomeric. We also show that it interacts with ICAM-1 through the DBLß domain alone, forming a 1:1 complex. These studies provide a first low resolution structural view of a PfEMP1...

  3. Mussel-inspired Fluoro-Polydopamine Functionalization of Titanium Dioxide Nanowires for Polymer Nanocomposites with Significantly Enhanced Energy Storage Capability

    National Research Council Canada - National Science Library

    Guanyao Wang; Xingyi Huang; Pingkai Jiang

    2017-01-01

    .... Herein, inspired by adhesive proteins in mussels, a facile modification by fluoro-polydopamine is employed to reinforce the compatibility of TiO2 nanowires in the fluoropolymer matrix. The loading of 2.5 vol % f-DOPA...

  4. Proteomic dataset of the sea urchin Paracentrotus lividus adhesive organs and secreted adhesive

    Directory of Open Access Journals (Sweden)

    Nicolas Lebesgue

    2016-06-01

    Full Text Available Sea urchins have specialized adhesive organs called tube feet, which mediate strong but reversible adhesion. Tube feet are composed by a disc, producing adhesive and de-adhesive secretions for substratum attachment, and a stem for movement. After detachment the secreted adhesive remains bound to the substratum as a footprint. Recently, a label-free quantitative proteomic approach coupled with the latest mass-spectrometry technology was used to analyze the differential proteome of Paracentrotus lividus adhesive organ, comparing protein expression levels in the tube feet adhesive part (the disc versus the non-adhesive part (the stem, and also to profile the proteome of the secreted adhesive (glue. This data article contains complementary figures and results related to the research article “Deciphering the molecular mechanisms underlying sea urchin reversible adhesion: a quantitative proteomics approach” (Lebesgue et al., 2016 [1]. Here we provide a dataset of 1384 non-redundant proteins, their fragmented peptides and expression levels, resultant from the analysis of the tube feet differential proteome. Of these, 163 highly over-expressed tube feet disc proteins (>3-fold, likely representing the most relevant proteins for sea urchin reversible adhesion, were further annotated in order to determine the potential functions. In addition, we provide a dataset of 611 non-redundant proteins identified in the secreted adhesive proteome, as well as their functional annotation and grouping in 5 major protein groups related with adhesive exocytosis, and microbial protection. This list was further analyzed to identify the most abundant protein groups and pinpoint putative adhesive proteins, such as Nectin, the most abundant adhesive protein in sea urchin glue. The obtained data uncover the key proteins involved in sea urchins reversible adhesion, representing a step forward to the development of new wet-effective bio-inspired adhesives.

  5. p38 mitogen-activated protein kinase interacts with vinculin at focal adhesions during fatty acid-stimulated cell adhesion.

    Science.gov (United States)

    George, Margaret D; Wine, Robert N; Lackford, Brad; Kissling, Grace E; Akiyama, Steven K; Olden, Kenneth; Roberts, John D

    2013-12-01

    Arachidonic acid stimulates cell adhesion by activating α2β1 integrins in a process that depends on protein kinases, including p38 mitogen activated protein kinase. Here, we describe the interaction of cytoskeletal components with key signaling molecules that contribute to the spreading of, and morphological changes in, arachidonic acid-treated MDA-MB-435 human breast carcinoma cells. Arachidonic acid-treated cells showed increased attachment and spreading on collagen type IV, as measured by electric cell-substrate impedance sensing. Fatty acid-treated cells displayed short cortical actin filaments associated with an increased number of β1 integrin-containing pseudopodia, whereas untreated cells displayed elongated stress fibers and fewer clusters of β1 integrins. Confocal microscopy of arachidonic acid-treated cells showed that vinculin and phospho-p38 both appeared enriched in pseudopodia and at the tips of actin filaments, and fluorescence ratio imaging indicated the increase was specific for the phospho-(active) form of p38. Immunoprecipitates of phospho-p38 from extracts of arachidonic acid-treated cells contained vinculin, and GST-vinculin fusion proteins carrying the central region of vinculin bound phospho-p38, whereas fusion proteins expressing the terminal portions of vinculin did not. These data suggest that phospho-p38 associates with particular domains on critical focal adhesion proteins that are involved in tumor cell adhesion and spreading, and that this association can be regulated by factors in the tumor microenvironment.

  6. Mussel-inspired modification of dextran for protein-resistant coatings of titanium oxide.

    Science.gov (United States)

    Park, Jae Yoon; Kim, Jee Seon; Nam, Yoon Sung

    2013-09-12

    Surface modification of inorganic materials to prevent non-specific protein adsorption is critically important for developing a biocompatible materials' platform for medical implantation, diagnostics, and therapeutics. Here we report mussel-inspired chemical modification of dextran for anti-fouling coatings of metal oxide. Catechols are conjugated to dextran via a carbamate ester linkage, producing catechol-grafted dextran with a grafting density of 7.3 mol.%. Titanium dioxide (TiO₂) is coated with the catechol-grafted dextran, and the anti-fouling effect of dextran coatings is examined by using the adsorption of human serum albumin. The mussel-inspired dextran coatings show excellent resistance to non-specific protein adsorption: the adsorption equilibrium constant (K) is 0.69 Lg(-1) for dextran-coated TiO₂ while that for pristine TiO₂ surface is 3.53 Lg(-1). This study suggests that catechol-grafted dextran is a promising material for effective anti-fouling coatings of implantable inorganic materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Flexible fiber-reinforced composites with improved interfacial adhesion by mussel-inspired polydopamine and poly(methyl methacrylate) coating.

    Science.gov (United States)

    Yi, Mi; Sun, Hongyang; Zhang, Hongcheng; Deng, Xuliang; Cai, Qing; Yang, Xiaoping

    2016-01-01

    To obtain a kind of light-curable fiber-reinforced composite for dental restoration, an excellent interfacial adhesion between the fiber and the acrylate resin matrix is quite essential. Herein, surface modification on glass fibers were carried out by coating them with poly(methyl methacrylate) (PMMA), polydopamine (PDA), or both. The PMMA or PDA coating was performed by soaking fibers in PMMA/acetone solution or dopamine aqueous solution. PDA/PMMA co-coated glass fibers were obtained by further soaking PDA-coated fibers in PMMA/acetone solution. These modified fibers were impregnated with bisphenol A glycidyl methacrylate (Bis-GMA)/triethylene glycol dimethacrylate (TEGDMA) (5:5, w/w) dental resin at a volume fraction of 75%, using unmodified fibers as reference. Light-cured specimens were submitted to evaluations including flexural properties, morphological observation, dynamic mechanical thermal analysis (DMTA) and pull-out test. In comparison with unmodified glass fibers, all the modified glass fibers showed enhancements in flexural strength and modulus of Bis-GMA/TEGDMA resin composites. Results of DMTA and pull-out tests confirmed that surface modification had significantly improved the interfacial adhesion between the glass fiber and the resin matrix. Particularly, the PDA/PMMA co-coated glass fibers displayed the most efficient reinforcement and the strongest interfacial adhesion due to the synergetic effects of PDA and PMMA. It indicated that co-coating method was a promising approach in modifying the interfacial compatibility between inorganic glass fiber and organic resin matrix. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. PROTEIN EXTRACTION FROM SECONDARY SLUDGE OF PAPER MILL WASTEWATER AND ITS UTILIZATION AS A WOOD ADHESIVE

    Directory of Open Access Journals (Sweden)

    Muhammad Pervaiz

    2011-04-01

    Full Text Available In this study, secondary sludge (SS from a kraft paper mill was used as a source of biomass to recover protein and investigate its potential use as a wood adhesive. The process of protein recovery involved disruption of the floc structure in alkaline medium to disintegrate and release intercellular contents into the aqueous phase followed by separation of soluble protein. Finally, the soluble protein was subjected to low pH precipitation and the pelletized sludge protein, referred to as recovered sludge protein (RSP was tested for crude protein, moisture, and other contents. A significant process yield of 90% in terms of precipitation of soluble protein from disintegrated sludge was estimated through calorimetric studies, whereas an overall material balance confirmed a RSP yield of up to 23% based on total suspended solids of raw sludge. The RSP containing 30% crude protein was used as a wood adhesive and its adhesion performance was compared with soy protein isolate (SPI and phenol formaldehyde (PF resin. The testing of plywood lap joints has shown up to 41% shear strength level of RSP adhesive compared to PF. This work demonstrates the technical feasibility and potential of SS as a biomass resource to develop eco-friendly adhesives for wood composite applications.

  9. Phosphoproteome reveals an atlas of protein signaling networks during osteoblast adhesion.

    Science.gov (United States)

    Milani, Renato; Ferreira, Carmen V; Granjeiro, José M; Paredes-Gamero, Edgar J; Silva, Rodrigo A; Justo, Giselle Z; Nader, Helena B; Galembeck, Eduardo; Peppelenbosch, Maikel P; Aoyama, Hiroshi; Zambuzzi, Willian F

    2010-04-01

    Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important regulatory mechanism in eukaryotes. Therefore, the goal of this study is to assess osteoblast adhesion through a molecular prism under a peptide array technology, revealing essential signaling proteins governing adhesion-related events. First, we showed that there are main morphological changes on osteoblast shape during adhesion up to 3 h. Second, besides classical proteins activated upon integrin activation, our results showed a novel network involving signaling proteins such as Rap1A, PKA, PKC, and GSK3beta during osteoblast adhesion on polystyrene. Third, these proteins were grouped in different signaling cascades including focal adhesion establishment, cytoskeleton rearrangement, and cell-cycle arrest. We have thus provided evidence that a global phosphorylation screening is able to yield a systems-oriented look at osteoblast adhesion, providing new insights for understanding of bone formation and improvement of cell-substratum interactions. Altogether, these statements are necessary means for further intervention and development of new approaches for the progress of tissue engineering.

  10. Propionibacterium freudenreichii Surface Protein SlpB Is Involved in Adhesion to Intestinal HT-29 Cells

    Science.gov (United States)

    do Carmo, Fillipe L. R.; Rabah, Houem; Huang, Song; Gaucher, Floriane; Deplanche, Martine; Dutertre, Stéphanie; Jardin, Julien; Le Loir, Yves; Azevedo, Vasco; Jan, Gwénaël

    2017-01-01

    Propionibacterium freudenreichii is a beneficial bacterium traditionally used as a cheese ripening starter and more recently for its probiotic abilities based on the release of beneficial metabolites. In addition to these metabolites (short-chain fatty acids, vitamins, and bifidogenic factor), P. freudenreichii revealed an immunomodulatory effect confirmed in vivo by the ability to protect mice from induced acute colitis. This effect is, however, highly strain-dependent. Local action of metabolites and of immunomodulatory molecules is favored by the ability of probiotics to adhere to the host cells. This property depends on key surface compounds, still poorly characterized in propionibacteria. In the present study, we showed different adhesion rates to cultured human intestinal cells, among strains of P. freudenreichii. The most adhesive one was P. freudenreichii CIRM-BIA 129, which is known to expose surface-layer proteins. We evidenced here the involvement of these proteins in adhesion to cultured human colon cells. We then aimed at deciphering the mechanisms involved in adhesion. Adhesion was inhibited by antibodies raised against SlpB, one of the surface-layer proteins in P. freudenreichii CIRM-BIA 129. Inactivation of the corresponding gene suppressed adhesion, further evidencing the key role of slpB product in cell adhesion. This work confirms the various functions fulfilled by surface-layer proteins, including probiotic/host interactions. It opens new perspectives for the understanding of probiotic determinants in propionibacteria, and for the selection of the most efficient strains within the P. freudenreichii species. PMID:28642747

  11. Adhesive layer-by-layer films of carboxymethylated cellulose nanofibril-dopamine covalent bioconjugates inspired by marine mussel threads.

    Science.gov (United States)

    Karabulut, Erdem; Pettersson, Torbjörn; Ankerfors, Mikael; Wågberg, Lars

    2012-06-26

    The preparation of multifunctional films and coatings from sustainable, low-cost raw materials has attracted considerable interest during the past decade. In this respect, cellulose-based products possess great promise due not only to the availability of large amounts of cellulose in nature but also to the new classes of nanosized and well-characterized building blocks of cellulose being prepared from trees or annual plants. However, to fully utilize the inherent properties of these nanomaterials, facile and also sustainable preparation routes are needed. In this work, bioinspired hybrid conjugates of carboxymethylated cellulose nanofibrils (CNFC) and dopamine (DOPA) have been prepared and layer-by-layer (LbL) films of these modified nanofibrils have been built up in combination with a branched polyelectrolyte, polyethyleneimine (PEI), to obtain robust, adhesive, and wet-stable nanocoatings on solid surfaces. It is shown that the chemical functionalization of CNFCs with DOPA molecules alters their conventional properties both in liquid dispersion and at the interface and also influences the LbL film formation by reducing the electrostatic interaction. Although the CNFC-DOPA conjugates show a lower colloidal stability in aqueous dispersions due to charge suppression, it was possible to prepare the LbL films through the consecutive deposition of the building blocks. Adhesive forces between multilayer films prepared using chemically functionalized CNFCs and a silica probe are much stronger in the presence of Fe(3+) than those between a multilayer film prepared from unmodified nanofibrils and a silica probe. The present work demonstrates a facile way to prepare chemically functionalized cellulose nanofibrils whereby more extended applications can produce novel cellulose-based materials with different functionalities.

  12. Redundant control of migration and adhesion by ERM proteins in vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Baeyens, Nicolas; Latrache, Iman; Yerna, Xavier [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium); Noppe, Gauthier; Horman, Sandrine [Pôle de Recherche Cardiovasculaire, IREC, Université Catholique de Louvain (Belgium); Morel, Nicole, E-mail: nicole.morel@uclouvain.be [Laboratory of Cell Physiology, IoNS, Université Catholique de Louvain (Belgium)

    2013-11-22

    Highlights: •The three ERM proteins are expressed in vascular smooth muscle cell. •ERM depletion inhibited PDGF-evoked migration redundantly. •ERM depletion increased cell adhesion redundantly. •ERM depletion did not affect PDGF-evoked Ca signal, Rac1 activation, proliferation. •ERM proteins control PDGF-induced migration by regulating adhesion. -- Abstract: Ezrin, radixin, and moesin possess a very similar structure with a C-terminal actin-binding domain and a N-terminal FERM interacting domain. They are known to be involved in cytoskeleton organization in several cell types but their function in vascular smooth muscle cells (VSMC) is still unknown. The aim of this study was to investigate the role of ERM proteins in cell migration induced by PDGF, a growth factor involved in pathophysiological processes like angiogenesis or atherosclerosis. We used primary cultured VSMC obtained from rat aorta, which express the three ERM proteins. Simultaneous depletion of the three ERM proteins with specific siRNAs abolished the effects of PDGF on cell architecture and migration and markedly increased cell adhesion and focal adhesion size, while these parameters were only slightly affected by depletion of ezrin, radixin or moesin alone. Rac1 activation, cell proliferation, and Ca{sup 2+} signal in response to PDGF were unaffected by ERM depletion. These results indicate that ERM proteins exert a redundant control on PDGF-induced VSMC migration by regulating focal adhesion turn-over and cell adhesion to substrate.

  13. Role of surface layer collagen binding protein from indigenous Lactobacillus plantarum 91 in adhesion and its anti-adhesion potential against gut pathogen.

    Science.gov (United States)

    Yadav, Ashok Kumar; Tyagi, Ashish; Kaushik, Jai Kumar; Saklani, Asha Chandola; Grover, Sunita; Batish, Virender Kumar

    2013-12-14

    Human feacal isolates were ascertain as genus Lactobacillus using specific primer LbLMA1/R16-1 and further identified as Lactobacillus plantarum with species specific primers Lpl-3/Lpl-2. 25 L. plantarum strains were further assessed for hydrophobicity following the microbial adhesion to hydrocarbons (MATH) method and colonization potentials based on their adherence to immobilized human collagen type-1. Surface proteins were isolated from selected L. plantarum 91(Lp91) strain. The purified collagen binding protein (Cbp) protein was assessed for its anti-adhesion activity against enteric Escherichia coli 0157:H7 pathogen on immobilized collagen. Four L. plantarum strains displayed high degree of hydrophobicity and significant adhesion to collagen. A 72 kDa protein was purified which reduced 59.71% adhesion of E. coli 0157:H7 on immobilized collagen as compared to control well during adhesion assay. Cbp protein is the major influencing factor in inhibition of E. coli 0157:H7 adhesion with extracellular matrix (ECM) components. Hydrophobicity and adhesion potential are closely linked attributes precipitating in better colonization potential of the lactobacillus strains. Cbp is substantiated as a crucial surface protein contributing in adhesion of lactobacillus strains. The study can very well be the platform for commercialization of indigenous probiotic strain once their functional attributes are clinically explored.

  14. A mucus adhesion promoting protein, MapA, mediates the adhesion of Lactobacillus reuteri to Caco-2 human intestinal epithelial cells.

    Science.gov (United States)

    Miyoshi, Yukihiro; Okada, Sanae; Uchimura, Tai; Satoh, Eiichi

    2006-07-01

    Lactobacillus reuteri is one of the dominant lactobacilli found in the gastrointestinal tract of various animals. A surface protein of L. reuteri 104R, mucus adhesion promoting protein (MapA), is considered to be an adhesion factor of this strain. We investigated the relation between MapA and adhesion of L. reuteri to human intestinal (Caco-2) cells. Quantitative analysis of the adhesion of L. reuteri strains to Caco-2 cells showed that various L. reuteri strains bind not only to mucus but also to intestinal epithelial cells. In addition, purified MapA bound to Caco-2 cells, and this binding inhibited the adhesion of L. reuteri in a concentration-dependent manner. Based on these observations, the adhesion of L. reuteri appears due to the binding of MapA to receptor-like molecules on Caco-2 cells. Further, far-western analysis indicated the existence of multiple receptor-like molecules in Caco-2 cells.

  15. The LAR transmembrane protein tyrosine phosphatase and a coiled-coil LAR-interacting protein co-localize at focal adhesions.

    OpenAIRE

    1995-01-01

    Focal adhesions are sites of cell-extracellular matrix interactions that function in anchoring stress fibers to the plasma membrane and in adhesion-mediated signal transduction. Both focal adhesion structure and signaling ability involve protein tyrosine phosphorylation. LAR is a broadly expressed transmembrane protein tyrosine phosphatase comprised of a cell adhesion-like ectodomain and two intracellular protein tyrosine phosphatase domains. We have identified a novel cytoplasmic 160 kDa pho...

  16. Adhesive proteins of stalked and acorn barnacles display homology with low sequence similarities.

    Directory of Open Access Journals (Sweden)

    Jaimie-Leigh Jonker

    Full Text Available Barnacle adhesion underwater is an important phenomenon to understand for the prevention of biofouling and potential biotechnological innovations, yet so far, identifying what makes barnacle glue proteins 'sticky' has proved elusive. Examination of a broad range of species within the barnacles may be instructive to identify conserved adhesive domains. We add to extensive information from the acorn barnacles (order Sessilia by providing the first protein analysis of a stalked barnacle adhesive, Lepas anatifera (order Lepadiformes. It was possible to separate the L. anatifera adhesive into at least 10 protein bands using SDS-PAGE. Intense bands were present at approximately 30, 70, 90 and 110 kilodaltons (kDa. Mass spectrometry for protein identification was followed by de novo sequencing which detected 52 peptides of 7-16 amino acids in length. None of the peptides matched published or unpublished transcriptome sequences, but some amino acid sequence similarity was apparent between L. anatifera and closely-related Dosima fascicularis. Antibodies against two acorn barnacle proteins (ab-cp-52k and ab-cp-68k showed cross-reactivity in the adhesive glands of L. anatifera. We also analysed the similarity of adhesive proteins across several barnacle taxa, including Pollicipes pollicipes (a stalked barnacle in the order Scalpelliformes. Sequence alignment of published expressed sequence tags clearly indicated that P. pollicipes possesses homologues for the 19 kDa and 100 kDa proteins in acorn barnacles. Homology aside, sequence similarity in amino acid and gene sequences tended to decline as taxonomic distance increased, with minimum similarities of 18-26%, depending on the gene. The results indicate that some adhesive proteins (e.g. 100 kDa are more conserved within barnacles than others (20 kDa.

  17. Electrochemical layer-by-layer approach to fabricate mechanically stable platinum black microelectrodes using a mussel-inspired polydopamine adhesive

    Science.gov (United States)

    Kim, Raeyoung; Nam, Yoonkey

    2015-04-01

    Objective. Platinum black (PtBK) has long been used for microelectrode fabrication owing to its high recording performance of neural signals. The porous structure of PtBK enlarges the surface area and lowers the impedance, which results in background noise reduction. However, the brittleness of PtBK has been a problem in practice. In this work, we report mechanically stable PtBK microelectrodes using a bioinspired adhesive film, polydopamine (pDA), while maintaining the low impedance of PtBK. Approach. The pDA layer was incorporated into the PtBK structure through electrochemical layer-by-layer deposition. Varying the number of layers and the order of materials, multi-layered pDA-PtBK hybrids were fabricated and the electrical properties, both impedance and charge injection limit, were evaluated. Main results. Multilayered pDA-PtBK hybrids had electrical impedances as low as PtBK controls and charge injection limit twice larger than controls. For the 30 min-ultrasonication agitation test, impedance levels rarely changed for some of the pDA-PtBK hybrids indicating that the pDA improved the mechanical property of the PtBK structures. The pDA-PtBK hybrid microelectrodes readily recorded neural signals of cultured hippocampal neurons, where background noise levels and signal-to-noise were 2.43 ∼ 3.23 μVrms and 28.4 ∼ 69.1, respectively. Significance. The developed pDA-PtBK hybrid microelectrodes are expected to be applicable to neural sensors for neural prosthetic studies.

  18. Biomedical and Clinical Importance of Mussel-Inspired Polymers and Materials.

    Science.gov (United States)

    Kaushik, Nagendra Kumar; Kaushik, Neha; Pardeshi, Sunil; Sharma, Jai Gopal; Lee, Seung Hyun; Choi, Eun Ha

    2015-11-11

    The substance secreted by mussels, also known as nature's glue, is a type of liquid protein that hardens rapidly into a solid water-resistant adhesive material. While in seawater or saline conditions, mussels can adhere to all types of surfaces, sustaining its bonds via mussel adhesive proteins (MAPs), a group of proteins containing 3,4-dihydroxyphenylalanine (DOPA) and catecholic amino acid. Several aspects of this adhesion process have inspired the development of various types of synthetic materials for biomedical applications. Further, there is an urgent need to utilize biologically inspired strategies to develop new biocompatible materials for medical applications. Consequently, many researchers have recently reported bio-inspired techniques and materials that show results similar to or better than those shown by MAPs for a range of medical applications. However, the susceptibility to oxidation of 3,4-dihydroxyphenylalanine poses major challenges with regard to the practical translation of mussel adhesion. In this review, various strategies are discussed to provide an option for DOPA/metal ion chelation and to compensate for the limitations imposed by facile 3,4-dihydroxyphenylalanine autoxidation. We discuss the anti-proliferative, anti-inflammatory, anti-microbial activity, and adhesive behaviors of mussel bio-products and mussel-inspired materials (MIMs) that make them attractive for synthetic adaptation. The development of biologically inspired adhesive interfaces, bioactive mussel products, MIMs, and arising areas of research leading to biomedical applications are considered in this review.

  19. Biomedical and Clinical Importance of Mussel-Inspired Polymers and Materials

    Directory of Open Access Journals (Sweden)

    Nagendra Kumar Kaushik

    2015-11-01

    Full Text Available The substance secreted by mussels, also known as nature’s glue, is a type of liquid protein that hardens rapidly into a solid water-resistant adhesive material. While in seawater or saline conditions, mussels can adhere to all types of surfaces, sustaining its bonds via mussel adhesive proteins (MAPs, a group of proteins containing 3,4-dihydroxyphenylalanine (DOPA and catecholic amino acid. Several aspects of this adhesion process have inspired the development of various types of synthetic materials for biomedical applications. Further, there is an urgent need to utilize biologically inspired strategies to develop new biocompatible materials for medical applications. Consequently, many researchers have recently reported bio-inspired techniques and materials that show results similar to or better than those shown by MAPs for a range of medical applications. However, the susceptibility to oxidation of 3,4-dihydroxyphenylalanine poses major challenges with regard to the practical translation of mussel adhesion. In this review, various strategies are discussed to provide an option for DOPA/metal ion chelation and to compensate for the limitations imposed by facile 3,4-dihydroxyphenylalanine autoxidation. We discuss the anti-proliferative, anti-inflammatory, anti-microbial activity, and adhesive behaviors of mussel bio-products and mussel-inspired materials (MIMs that make them attractive for synthetic adaptation. The development of biologically inspired adhesive interfaces, bioactive mussel products, MIMs, and arising areas of research leading to biomedical applications are considered in this review.

  20. Adhesion mechanism in a DOPA-deficient foot protein from green mussels†

    Science.gov (United States)

    Hwang, Dong Soo; Zeng, Hongbo; Lu, Qingye; Israelachvili, Jacob; Waite, J. Herbert

    2012-01-01

    The holdfast or byssus of Asian green mussels, Perna viridis, contains a foot protein, pvfp-1, that differs in two respects from all other known adhesive mussel foot proteins (mfp): (1) instead of the hallmark L-3,4-dihydroxyphenylalanine (DOPA) residues in mfp-1, for example, pvfp-1 contains C2-mannosyl-7-hydroxytryptophan (Man7OHTrp). (2) In addition, pvfp-1 chains are not monomeric like mfp-1 but trimerized by collagen and coiled-coil domains near the carboxy terminus after a typical domain of tandemly repeated decapeptides. Here, the contribution of these peculiarities to adhesion was examined using a surface forces apparatus (SFA). Unlike previously studied mfp-1s, pvfp-1 showed significant adhesion to mica and, in symmetric pvfp-1 films, substantial cohesive interactions were present at pH 5.5. The role of Man7OHTrp in adhesion is not clear, and a DOPA-like role for Man7OHTrp in metal complexation (e.g., Cu2+, Fe3+) was not observed. Instead, cation–π interactions with low desolvation penalty between Man7OHTrp and lysyl side chains and conformational changes (raveling and unraveling of collagen helix and coiled-coil domains) are the best explanations for the strong adhesion between pvfp-1 monomolecular films. The strong adhesion mechanism induced by cation–π interactions and conformational changes in pvfp-1 provides new insights for the development of biomimetic underwater adhesives. PMID:23105946

  1. Photoactivatable Mussel-Based Underwater Adhesive Proteins by an Expanded Genetic Code.

    Science.gov (United States)

    Hauf, Matthias; Richter, Florian; Schneider, Tobias; Faidt, Thomas; Martins, Berta M; Baumann, Tobias; Durkin, Patrick; Dobbek, Holger; Jacobs, Karin; Möglich, Andreas; Budisa, Nediljko

    2017-09-19

    Marine mussels exhibit potent underwater adhesion abilities under hostile conditions by employing 3,4-dihydroxyphenylalanine (DOPA)-rich mussel adhesive proteins (MAPs). However, their recombinant production is a major biotechnological challenge. Herein, a novel strategy based on genetic code expansion has been developed by engineering efficient aminoacyl-transfer RNA synthetases (aaRSs) for the photocaged noncanonical amino acid ortho-nitrobenzyl DOPA (ONB-DOPA). The engineered ONB-DOPARS enables in vivo production of MAP type 5 site-specifically equipped with multiple instances of ONB-DOPA to yield photocaged, spatiotemporally controlled underwater adhesives. Upon exposure to UV light, these proteins feature elevated wet adhesion properties. This concept offers new perspectives for the production of recombinant bioadhesives. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Protein adhesion on dental surfaces-a combined surface analytical approach.

    Science.gov (United States)

    Müller, Christine; Wald, Johanna; Hoth-Hannig, Wiebke; Umanskaya, Natalia; Scholz, Daniel; Hannig, Matthias; Ziegler, Christiane

    2011-05-01

    Protein adsorption is a field of huge interest in a number of application fields. Information on protein adhesion is accessible by a variety of methods. However, the results obtained are significantly influenced by the applied technique. The objective of this work was to understand the role of adhesion forces (obtained by scanning force spectroscopy, SFS) in the process of protein adsorption and desorption. In SFS, the protein is forced to and retracted from the surface, even under unfavorable conditions, in contrast to the natural situation. Furthermore, adhesion forces are correlated with adhesion energies, neglecting the entropic part in the Gibbs enthalpy. In this context, dynamic contact angle (DCA) measurements were performed to identify the potential of this method to complement SFS data. In DCA measurements, the protein diffuses voluntarily to the surface and information on surface coverage and reversibility of adsorption is obtained, including entropic effects (conformational changes and hydrophobic effect). It could be shown that the surface coverage (by DCA) of bovine serum albumin on dental materials correlates well with the adhesion forces (by SFS) if no hydrophobic surface is involved. On those, the entropic hydrophobic effect plays a major role. As a second task, the reversibility of the protein adsorption, i.e., the voluntary desorption as studied by DCA, was compared to the adhesion forces. Here, a correlation between low adhesion forces and good reversibility could be found as long as no covalent bonds were involved. The comparative study of DCA and SFS, thus, leads to a more detailed picture of the complete adsorption/desorption cycle.

  3. Soy Flour Adhesive Strength Compared with That of Purified Soy Proteins*

    Science.gov (United States)

    Linda Lorenz; Michael Birkeland; Chera Daurio; Charles R. Frihart

    2015-01-01

    Except for the substitution of soy flour in phenolic resins (Frihart et al. 2013) and the use of soy flour at high pHs (Lambuth 2003), the literature on soy protein properties for adhesives has mainly focused on soy protein isolate and specific protein fractions (Sun 2005b). The assumption is that proteins are the main portion of soy flour giving bond strength and the...

  4. Bacterial binding to extracellular proteins - in vitro adhesion

    DEFF Research Database (Denmark)

    Schou, C.; Fiehn, N.-E.

    1999-01-01

    Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis......Viridans streptococci, bacterial adherence, extracellular matrix proteins, surface receptors, endocarditis...

  5. Effect of Monocyte Chemotactic Protein-1 on the Intraperitoneal Adhesion Formation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to study the role of monocyte chemotactic protein-1 (MCP-1) in the intra-peritoneal adhesion formation, 23 infertile patients undergoing laparoscopic operation were divided into two groups: experimental group including 12 patients with intra-peritoneal adhesion and control group including 11 patients without intra-peritoneal adhesion. Peritoneal fluid (PF) and peritoneum were collected from these patients during laparoscopic examination. The expression levels of MCP-l protein and MCP-1 mRNA were detected by using enzyme-linked immunosorbent assay (ELISA) and dot blot analysis method respectively. It was found that the levels of MCP-1 protein in PF of the patients with peritoneal adhesion were significantly higher than in the control group (0. 44±0.11 ng/ml vs 0. 19+0. 09 ng/ml respectively, P<0. 01 ). The level of MCP-1 mRNA in the peritoneum of the patients with peritoneal adhesion was significantly higher than in the control group (48.61±3.72 vs 19. 87±2.54 respectively, P<0. 01). It was suggested that MCP-1 might play a role in the adhesion formation, and chemotactic cytokines expressing in the peritoneal mesothelial cells might be take part in the process.

  6. Platelet adhesion onto wettability gradient surfaces in the absence and presence of plasma proteins.

    Science.gov (United States)

    Lee, J H; Lee, H B

    1998-08-01

    A wettability gradient was prepared on lowdensity polyethylene (PE) sheets by treating them in air with a corona from a knife-type electrode the power of which increased gradually along the sample length. The PE surfaces oxidized gradually with the increasing corona power and a wettability gradient was created on the surfaces, as evidenced by the measurement of water contact angles, Fourier transform infrared spectroscopy in the attenuated total reflectance mode, and electron spectroscopy for chemical analysis. The wettability gradient surfaces prepared were used to investigate the adhesion behavior of platelets in the absence and presence of plasma proteins in terms of the surface hydrophilicity/hydrophobicity of polymeric materials. The platelets adhered to the wettability gradient surfaces along the sample length were counted and examined by scanning electron microscopy (SEM). It was observed that the platelet adhesion in the absence of plasma proteins increased gradually as the surface wettability increased along the sample length. The platelets adhered to the hydrophilic positions of the gradient surface also were more activated (possessed more pseudo pods as examined by SEM) than on the more hydrophobic ones. However, platelet adhesion in the presence of plasma proteins decreased gradually with the increasing surface wettability; the platelets adhered to the surface also were more activated on the hydrophobic positions of the gradient surface. This result is closely related to plasma protein adsorption on the surface. Plasma protein adsorption on the wettability gradient surface increased with the increasing surface wettability. More plasma protein adsorption on the hydrophilic positions of the gradient surface caused less platelet adhesion, probably due to platelet adhesion inhibiting proteins, such as high-molecular-weight kininogen, which preferably adsorbs onto the surface by the so-called Vroman effect. It seems that both the presence of plasma proteins

  7. Adhesive performance of sorghum protein extracted from sorghum DDGS and flour

    Science.gov (United States)

    Distillers dried grains with solubles (DDGS) is the main co-product from grain-based ethanol production. The objective of this research was to compare the adhesive performance of three types of sorghum proteins: acetic acid-extracted sorghum protein from DDGS (PI), aqueous ethanol-extracted sorghum ...

  8. A hot water extract of Curcuma longa inhibits adhesion molecule protein expression and monocyte adhesion to TNF-α-stimulated human endothelial cells.

    Science.gov (United States)

    Kawasaki, Kengo; Muroyama, Koutarou; Yamamoto, Norio; Murosaki, Shinji

    2015-01-01

    The recruitment of arterial leukocytes to endothelial cells is an important step in the progression of various inflammatory diseases. Therefore, its modulation is thought to be a prospective target for the prevention or treatment of such diseases. Adhesion molecules on endothelial cells are induced by proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), and contribute to the recruitment of leukocytes. In the present study, we investigated the effect of hot water extract of Curcuma longa (WEC) on the protein expression of adhesion molecules, monocyte adhesion induced by TNF-α in human umbilical vascular endothelial cells (HUVECs). Treatment of HUVECs with WEC significantly suppressed both TNF-α-induced protein expression of adhesion molecules and monocyte adhesion. WEC also suppressed phosphorylation and degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα) induced by TNF-α in HUVECs, suggesting that WEC inhibits the NF-κB signaling pathway.

  9. Preliminary study on chicken feather protein-based wood adhesives

    Science.gov (United States)

    Zehui Jiang; Daochun Qin; Chung-Yun Hse; Monlin Kuo; Zhaohui Luo; Ge Wang; Yan Yu

    2008-01-01

    The objective of this preliminary study was to partially replace phenol in the synthesis of phenol-formaldehyde resin with feather protein. Feather protein–based resins, which contained one part feather protein and two parts phenol, were formulated under the conditions of two feather protein hydrolysis methods (with and without presence of phenol during...

  10. Wheat proteins enhance stability and function of adhesion molecules in cryopreserved hepatocytes.

    Science.gov (United States)

    Grondin, Mélanie; Hamel, Francine; Averill-Bates, Diana A; Sarhan, Fathey

    2009-01-01

    Cryopreserved hepatocytes with good hepatospecific functions upon thawing are important for clinical transplantation and for in vitro drug toxicity testing. However, cryopreservation reduces viability and certain hepatospecific functions, but the most pronounced change is diminished attachment efficiency of hepatocytes. Adhesion of cells to the extracellular matrix and cell-cell contacts are crucial for many aspects of cellular function. These processes are partly mediated and controlled by cellular adhesion molecules. The mechanisms responsible for reduced attachment efficiency of cryopreserved hepatocytes are not well understood. To address this question, we investigated the effect of a new cryopreservation procedure, using wheat proteins (WPs) or mixtures of recombinant forms of wheat freezing tolerance-associated proteins, on the stability of three important adhesion molecules (beta1-integrin, E-cadherin, and beta-catenin). Immunoblot analyses revealed that the levels of beta1-integrin, E-cadherin, and beta-catenin were much lower in cryopreserved rat hepatocytes, when compared to fresh cells. Protein expression of the adhesion molecules was generally lower in cells cryopreserved with DMSO, compared to WPs. Moreover, the stability of the adhesion molecules was not affected by cryopreservation to the same degree, with more pronounced decreases occurring for beta1-integrin (62-74%) > beta-catenin (51-58%) > E-cadherin (21-37%). However, when hepatocytes were cryopreserved with partially purified WPs (SulWPE, AcWPE) or with mixtures of recombinant wheat proteins, there was a clear protective effect against the loss of protein expression of beta1-integrin, E-cadherin, and beta-catenin. Protein expression was only 10-20% lower than that observed in fresh hepatocytes. These findings clearly demonstrate that WPs, and more particularly, partially purified WPs and recombinant wheat proteins, were more efficient for cryopreservation of rat hepatocytes by maintaining good

  11. Cell adhesion controlled by adhesion G protein-coupled receptor GPR124/ADGRA2 is mediated by a protein complex comprising intersectins and Elmo-Dock.

    Science.gov (United States)

    Hernández-Vásquez, Magda Nohemí; Adame-García, Sendi Rafael; Hamoud, Noumeira; Chidiac, Rony; Reyes-Cruz, Guadalupe; Gratton, Jean Philippe; Côté, Jean-François; Vázquez-Prado, José

    2017-07-21

    Developmental angiogenesis and the maintenance of the blood-brain barrier involve endothelial cell adhesion, which is linked to cytoskeletal dynamics. GPR124 (also known as TEM5/ADGRA2) is an adhesion G protein-coupled receptor family member that plays a pivotal role in brain angiogenesis and in ensuring a tight blood-brain barrier. However, the signaling properties of GPR124 remain poorly defined. Here, we show that ectopic expression of GPR124 promotes cell adhesion, additive to extracellular matrix-dependent effect, coupled with filopodia and lamellipodia formation and an enrichment of a pool of the G protein-coupled receptor at actin-rich cellular protrusions containing VASP, a filopodial marker. Accordingly, GPR124-expressing cells also displayed increased activation of both Rac and Cdc42 GTPases. Mechanistically, we uncover novel direct interactions between endogenous GPR124 and the Rho guanine nucleotide exchange factors Elmo/Dock and intersectin (ITSN). Small fragments of either Elmo or ITSN1 that bind GPR124 blocked GPR124-induced cell adhesion. In addition, Gβγ interacts with the C-terminal tail of GPR124 and promotes the formation of a GPR124-Elmo complex. Furthermore, GPR124 also promotes the activation of the Elmo-Dock complex, as measured by Elmo phosphorylation on a conserved C-terminal tyrosine residue. Interestingly, Elmo and ITSN1 also interact with each other independently of their GPR124-recognition regions. Moreover, endogenous phospho-Elmo and ITSN1 co-localize with GPR124 at lamellipodia of adhering endothelial cells, where GPR124 expression contributes to polarity acquisition during wound healing. Collectively, our results indicate that GPR124 promotes cell adhesion via Elmo-Dock and ITSN. This constitutes a previously unrecognized complex formed of atypical and conventional Rho guanine nucleotide exchange factors for Rac and Cdc42 that is putatively involved in GPR124-dependent angiogenic responses. © 2017 by The American Society for

  12. Facile preparation of mussel-inspired polyurethane hydrogel and its rapid curing behavior.

    Science.gov (United States)

    Sun, Peiyu; Wang, Jing; Yao, Xiong; Peng, Ying; Tu, Xiaoxiong; Du, Pengfei; Zheng, Zhen; Wang, Xinling

    2014-08-13

    A facile method was found to incorporate a mussel-inspired adhesive moiety into synthetic polymers, and mussel mimetic polyurethanes were developed as adhesive hydrogels. In these polymers, a urethane backbone was substituted for the polyamide chain of mussel adhesive proteins, and dopamine was appended to mimic the adhesive moiety of adhesive proteins. A series of mussel mimetic polyurethanes were created through a step-growth polymerization based on hexamethylene diisocyanate as a hard segment, PEG having different molecular weights as a soft segment, and lysine-dopamine as a chain extender. Upon a treatment with Fe(3+), the aqueous mussel mimetic polyurethane solutions can be triggered by pH adjustment to form adhesive hydrogels instantaneously; these materials can be used as injectable adhesive hydrogels. Upon a treatment with NaIO4, the mussel mimetic polyurethane solutions can be cured in a controllable period of time. The successful combination of the unique mussel-inspired adhesive moiety with a tunable polyurethane structure can result in a new kind of mussel-inspired adhesive polymers.

  13. Adhesion properties of Lactobacillus rhamnosus mucus-binding factor to mucin and extracellular matrix proteins.

    Science.gov (United States)

    Nishiyama, Keita; Nakamata, Koichi; Ueno, Shintaro; Terao, Akari; Aryantini, Ni Putu Desy; Sujaya, I Nengah; Fukuda, Kenji; Urashima, Tadasu; Yamamoto, Yuji; Mukai, Takao

    2015-01-01

    We previously described potential probiotic Lactobacillus rhamnosus strains, isolated from fermented mare milk produced in Sumbawa Island, Indonesia, which showed high adhesion to porcine colonic mucin (PCM) and extracellular matrix (ECM) proteins. Recently, mucus-binding factor (MBF) was found in the GG strain of L. rhamnosus as a mucin-binding protein. In this study, we assessed the ability of recombinant MBF protein from the FSMM22 strain, one of the isolates of L. rhamnosus from fermented Sumbawa mare milk, to adhere to PCM and ECM proteins by overlay dot blot and Biacore assays. MBF bound to PCM, laminin, collagen IV, and fibronectin with submicromolar dissociation constants. Adhesion of the FSMM22 mbf mutant strain to PCM and ECM proteins was significantly less than that of the wild-type strain. Collectively, these results suggested that MBF contribute to L. rhamnosus host colonization via mucin and ECM protein binding.

  14. Towards gecko-feet-inspired bandages.

    Science.gov (United States)

    Yanik, Mehmet Fatih

    2009-01-01

    A novel bandage inspired by gecko feet might one day be used during emergencies and internal surgeries. The bandage uses a combination of nanofabricated structures, biodegradable materials and adhesive surface chemistry that allows adhesion onto even wet, moving tissue.

  15. Identification of macrophage external membrane proteins and their possible role in cell adhesion.

    Science.gov (United States)

    Pearlstein, E; Dienstman, S R; Defendi, V

    1978-10-01

    Starch-activated mouse peritoneal macrophages (STpMAC) plated on plastic demonstrate the adhesive properties typical for activated pMAC: attaching as round cells and, within 15 min, spreading out with marginal membrane ruffles. These attached STpMAC were labeled by lactoperoxidase-catalysed 125I surface iodination, sodium dodecyl-sulfate-lysed, and the lysates electrophoresed on polyacrylamide gels which were examined by autoradiography. The STpMAC morphological phenotype correlates with the labeling of a particular protein (195,000, estimated mol wt). Normal pMAC (NpMAC), from unstimulated mice, do not spread and do not display the 195,000 band. Both pMAC band patterns, including the 195,000 band, are relatively resistant to trypsin digestion, as is pMAC adhesion itself trypsin-resistant. Neither class of pMAC exhibits fibronectin (Cell Adhesion Factor, LETS protein) which is a component in the adhesive matrix of cells forming trypsin-sensitive monolayers. When pMAC are tested against antifibronectin antibody, these cells do not give immunofluorescent staining. In summary, two functions in pMAC adhesion, enzyme resistance and the ability to spread, appear related to molecular properties distinctive for pMAC surface protein.

  16. [Study on FAK regulation of migration of vascular endothelial cells depending upon focal adhesion proteins].

    Science.gov (United States)

    Gao, Min; Liu, Xiaoheng; Sun, Heng; Ren, Hongyi; Wang, Lijuan; Shen, Yang

    2013-06-01

    Tumor angiogenesis induced by vascular endothelial cells (VECs) migration is a necessary condition for tumor growth and metastasis. The purpose of this study is to investigate the effect of focal adhesion kinase (FAK) inhibitor (50nmol/mL) on the adhesion and migration of endothelial cells(ECs) and the expression of focal adhesion proteins vinculin, talin and paxillin. Scratch wound migration assay was performed to examine the effect of FAK inhibitor with 50nmol/mL on ECs migration at 0, 5, 10, 30, 60 and 120min, respectively. And immunofluorescence analysis was performed to detect the expression of F-actin in ECs treated with FAK inhibitor within 2h. Western blot was carried out to determine the effect of FAK inhibitor on expression of vinculin, talin and paxillin proteins. The results showed that the migration distance and the expression of F-actin in ECs treated with FAK inhibitor decreased significantly compared with that of the controls, and the level of vinculin showed no significant difference with increasing of treated time of FAK inhibitor. However, the talin and paxillin showed an identical decreasing tendency in 5-10min, but slowly going up in 30min and then after subsequently decreasing. The results of this study proved that blocking phosphorylation of FAK could inhibit VECs adhesion and migration by downregulating focal adhesion proteins so that it may inhibit tumor angiogenesis. This may provide a new approach for tumor therapy.

  17. Hydrophobic enhancement of Dopa-mediated adhesion in a mussel foot protein.

    Science.gov (United States)

    Wei, Wei; Yu, Jing; Broomell, Christopher; Israelachvili, Jacob N; Waite, J Herbert

    2013-01-09

    Dopa (3,4-dihydroxyphenylalanine) is recognized as a key chemical signature of mussel adhesion and has been adopted into diverse synthetic polymer systems. Dopa's notorious susceptibility to oxidation, however, poses significant challenges to the practical translation of mussel adhesion. Using a surface forces apparatus to investigate the adhesion of mussel foot protein 3 (Mfp3) "slow", a hydrophobic protein variant of the Mfp3 family in the plaque, we have discovered a subtle molecular strategy correlated with hydrophobicity that appears to compensate for Dopa instability. At pH 3, where Dopa is stable, Mfp3 slow, like Mfp3 "fast" adhesion to mica, is directly proportional to the mol % of Dopa present in the protein. At pH of 5.5 and 7.5, however, loss of adhesion in Mfp3 slow was less than half that occurring in Mfp3 fast, purportedly because Dopa in Mfp3 slow is less prone to oxidation. Indeed, cyclic voltammetry showed that the oxidation potential of Dopa in Mfp3 slow is significantly higher than in Mfp3 fast at pH of 7.5. A much greater difference between the two variants was revealed in the interaction energy of two symmetric Mfp3 slow films (E(ad) = -3 mJ/m(2)). This energy corresponds to the energy of protein cohesion which is notable for its reversibility and pH independence. Exploitation of aromatic hydrophobic sequences to protect Dopa against oxidation as well as to mediate hydrophobic and H-bonding interactions between proteins provides new insights for developing effective artificial underwater adhesives.

  18. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics.

    Science.gov (United States)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert

    2005-06-01

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain architecture and natural product inspired compound library design. Domains and proteins identified as being structurally similar in their ligand-sensing cores are grouped in a protein structure similarity cluster (PSSC). Natural products can be considered as evolutionary pre-validated ligands for multiple proteins and therefore natural products that are known to interact with one of the PSSC member proteins are selected as guiding structures for compound library synthesis. Application of this novel strategy for compound library design provided enhanced hit rates in small compound libraries for structurally similar proteins.

  19. Adhesion dynamics of porcine esophageal fibroblasts on extracellular matrix protein-functionalized poly(lactic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Cai Ning; Gong Yingxue; Chan, Vincent; Liao Kin [School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Chian, Kerm Sin [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore 639798 (Singapore)], E-mail: askliao@ntu.edu.sg

    2008-03-01

    Effective attachment of esophageal cells on biomaterials is one important requirement in designing engineered esophagus substitute for esophageal cancer treatment. In this study, poly(lactic acid) (PLA) was subjected to surface modification by coupling extracellular matrix (ECM) proteins on its surface to promote cell adhesion. Two typical ECM proteins, collagen type I (COL) and fibronectin (FN), were immobilized on the PLA surface with the aid of glutaraldehyde as a cross linker between aminolyzed PLA and ECM proteins. By using confocal reflectance interference contrast microscopy (C-RICM) integrating with phase contrast microscopy, the long-term adhesion dynamics of porcine esophageal fibroblasts (PEFs) on four types of surfaces (unmodified PLA, PLA-COOH, PLA-COL and PLA-FN) was investigated during 24 h of culture. It is demonstrated by C-RICM results that PEFs form strong adhesion contact on all four types of surfaces at different stages of cell seeding. Among the four surfaces, PEFs on the PLA-FN surface reach the maximum adhesion energy (9.5 x 10{sup -7} J m{sup -2}) in the shortest time (20 min) during the initial stage of cell seeding. After adhesion energy reaches the maximum value, PEFs maintain their highly deformed geometries till they reached a steady state after 20 h of culture. F-actin immunostaining results show that the evolvement of spatial organization of F-actin is tightly correlated with the formation of adhesion contact and cell spreading. Furthermore, the cell attachment ratio of PEFs on PLA in 2 h is only 26% compared with 88% on PLA-FN, 73% on PLA-COL and 36% on PLA-COOH. All the results demonstrate the effect of surface functionalization on the biophysical responses of PEFs in cell adhesion. Fibronectin-immobilized PLA demonstrates promising potential for application as an engineered esophagus substitute.

  20. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition.

    Directory of Open Access Journals (Sweden)

    Claire M Elkins

    Full Text Available Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS, borate buffered saline (BBS, or Sensitive Eyes Plus Saline Solution (Sensitive Eyes, either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.

  1. Tailored Poly(2-oxazoline) Polymer Brushes to Control Protein Adsorption and Cell Adhesion

    KAUST Repository

    Zhang, Ning

    2012-05-18

    POx bottle-brush brushes (BBBs) are synthesized by SIPGP of 2-isopropenyl-2-oxazoline and consecutive LCROP of 2-oxazolines on 3-aminopropyltrimethoxysilane-modified silicon substrates. The side chain hydrophilicity and polarity are varied. The impact of the chemical composition and architecture of the BBB upon protein (fibronectin) adsorption and endothelial cell adhesion are investigated and prove extremely low protein adsorption and cell adhesion on BBBs with hydrophilic side chains such as poly(2-methyl-2-oxazoline) and poly(2-ethyl-2-oxazoline). The influence of the POx side chain terminal function upon adsorption and adhesion is minor but the side chain length has a significant effect on bioadsorption. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The role of serum proteins in Staphylococcus aureus adhesion to ethylene glycol coated surfaces.

    Science.gov (United States)

    Schuster, Swen; Yu, Wenqi; Nega, Mulugeta; Chu, Ya-Yun; Zorn, Stefan; Zhang, Fajun; Götz, Friedrich; Schreiber, Frank

    2014-11-01

    Bacterial adhesion on implants is a first step in the development of chronic foreign body associated infections. Finding strategies to minimize bacterial adhesion may contribute to minimize such infections. It is known that surfaces with oligo-ethylene-glycol (EG3OMe) or poly-ethylene-glycol (PEG2k) terminations decrease unspecific protein adsorption and bacterial adhesion. However, little is known about the influence of serum and its components on bacterial adhesion. We therefore prepared two coatings on gold surface with HS-(CH2)11EG3OMe (EG3OMe) and PEG2k-thiol and studied the role of bovine serum albumin (BSA), γ-globulins, and serum on Staphylococcus aureus adhesion. While BSA and lysozyme showed no adherence even when applied at very high concentrations (100 mg/ml), γ-globulins adsorbed already from 10 mg/ml on. The adsorption of γ-globulins was, however, significantly decreased when it was mixed with BSA in a ratio of 3:1, as it is in the serum. Pretreatment of EG3OMe and PEG2k coatings with γ-globulins or serum strongly promoted adherence of S. aureus when resuspended in buffer, suggesting that γ-globulins play a pivotal role in promoting S. aureus adhesion by its IgG binding proteins; the finding that a spa-deletion mutant, lacking the IgG binding protein A, showed decreased adherence corroborated this. Similarly, when S. aureus was pretreated with serum or γ-globulins its adherence was also significantly decreased. Our findings show that particularly γ-globulins bind to the coated surfaces thus mediating adherence of S. aureus via its protein A. As pretreatment of S. aureus with serum or γ-globulins significantly decreased adherence, treatment of patients with γ-globulins before implant surgery might lower the risk of implant-associated infections. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Substrate, focal adhesions, and actin filaments: a mechanical unit with a weak spot for mechanosensitive proteins

    Science.gov (United States)

    Kirchenbüchler, David; Born, Simone; Kirchgeßner, Norbert; Houben, Sebastian; Hoffmann, Bernd; Merkel, Rudolf

    2010-05-01

    Mechanosensing is a vital prerequisite for dynamic remodeling of focal adhesions and cytoskeletal structures upon substrate deformation. For example, tissue formation, directed cell orientation or cell differentiation are regulated by such mechanosensing processes. Focal adhesions and the actin cytoskeleton are believed to be involved in these processes, but where mechanosensing molecules are located and how elastic substrate, focal adhesions and the cytoskeleton couple with each other upon substrate deformation still remains obscure. To approach these questions we have developed a sensitive method to apply defined spatially decaying deformation fields to cells cultivated on ultrasoft elastic substrates and to accurately quantify the resulting displacements of the actin cytoskeleton, focal adhesions, as well as the substrate. Displacement fields were recorded in live cell microscopy by tracking either signals from fluorescent proteins or marker particles in the substrate. As model cell type we used myofibroblasts. These cells are characterized by highly stable adhesion and force generating structures but are still able to detect mechanical signals with high sensitivity. We found a rigid connection between substrate and focal adhesions. Furthermore, stress fibers were found to be barely extendable almost over their whole lengths. Plastic deformation took place only at the very ends of actin filaments close to focal adhesions. As a result, this area became elongated without extension of existing actin filaments by polymerization. Both ends of the stress fibers were mechanically coupled with detectable plastic deformations on either site. Interestingly, traction force dependent substrate deformation fields remained mostly unaffected even when stress fiber elongations were released. These data argue for a location of mechanosensing proteins at the ends of actin stress fibers and describe, except for these domains, the whole system to be relatively rigid for tensile

  4. The human and mouse repertoire of the adhesion family of G-protein-coupled receptors.

    Science.gov (United States)

    Bjarnadóttir, Thóra K; Fredriksson, Robert; Höglund, Pär J; Gloriam, David E; Lagerström, Malin C; Schiöth, Helgi B

    2004-07-01

    The adhesion G-protein-coupled receptors (GPCRs) (also termed LN-7TM or EGF-7TM receptors) are membrane-bound proteins with long N-termini containing multiple domains. Here, 2 new human adhesion-GPCRs, termed GPR133 and GPR144, have been found by searches done in the human genome databases. Both GPR133 and GPR144 have a GPS domain in their N-termini, while GPR144 also has a pentraxin domain. The phylogenetic analyses of the 2 new human receptors show that they group together without close relationship to the other adhesion-GPCRs. In addition to the human genes, mouse orthologues to those 2 and 15 other mouse orthologues to human were identified (GPR110, GPR111, GPR112, GPR113, GPR114, GPR115, GPR116, GPR123, GPR124, GPR125, GPR126, GPR128, LEC1, LEC2, and LEC3). Currently the total number of human adhesion-GPCRs is 33. The mouse and human sequences show a clear one-to-one relationship, with the exception of EMR2 and EMR3, which do not seem to have orthologues in mouse. EST expression charts for the entire repertoire of adhesion-GPCRs in human and mouse were established. Over 1600 ESTs were found for these receptors, showing widespread distribution in both central and peripheral tissues. The expression patterns are highly variable between different receptors, indicating that they participate in a number of physiological processes. Copyright 2003 Elsevier Inc.

  5. New functions and signaling mechanisms for the class of adhesion G protein-coupled receptors

    DEFF Research Database (Denmark)

    Liebscher, Ines; Ackley, Brian; Araç, Demet

    2014-01-01

    The class of adhesion G protein-coupled receptors (aGPCRs), with 33 human homologs, is the second largest family of GPCRs. In addition to a seven-transmembrane α-helix-a structural feature of all GPCRs-the class of aGPCRs is characterized by the presence of a large N-terminal extracellular region...

  6. Comparison of the adhesive performances of soy meal, water washed meal fractions, and protein isolates

    Science.gov (United States)

    Adhesive bonding of wood plays an increasing role in the forest products industry and is a key factor for efficiently utilizing timber and other lignocellulosic resources. In this work, we obtained five soy meal products through commercial sources or in-house preparations. The protein content was 49...

  7. Role of Cbl-associated protein/ponsin in receptor tyrosine kinase signaling and cell adhesion

    Directory of Open Access Journals (Sweden)

    Ritva Tikkanen

    2012-10-01

    Full Text Available The Cbl-associated protein/ponsin (CAP is an adaptor protein that contains a so-called Sorbin homology (SoHo domain and three Src homology 3 (SH3 domains which are engaged in diverse protein-protein interactions. CAP has been shown to function in the regulation of the actin cytoskeleton and cell adhesion and to be involved in the differentiation of muscle cells and adipocytes. In addition, it participates in signaling pathways through several receptor tyrosine kinases such as insulin and neurotrophin receptors. In the last couple of years, several studies have shed light on the details of these processes and identified novel interaction partners of CAP. In this review, we summarize these recent findings and provide an overview on the function of CAP especially in cell adhesion and membrane receptor signaling.

  8. Adhesive ability means inhibition activities for lactobacillus against pathogens and S-layer protein plays an important role in adhesion.

    Science.gov (United States)

    Zhang, Wenming; Wang, Haifeng; Liu, Jianxin; Zhao, Yunhao; Gao, Kan; Zhang, Juan

    2013-08-01

    Eighty-five strains of lactobacillus were isolated from the pig intestine and identified by sequencing analysis based on 16S rRNA gene, from which five lactobacillus strains with high adhesive ability were selected. The inhibition ability of the five lactobacillus strains with or without S-layer proteins against adherence of Escherichia coli K88 and Salmonella enteritidis 50335 to Caco-2 was evaluated in vitro with Lactobacillus rhamnosus GG strain (LGG) as a positive control. In addition, tolerance of lactobacilli to heat, acid, bile, Zn(2+) and Cu(2+) were assessed. All five selected strains, Lactobacillus salivarius ZJ614 (JN981856), Lactobacillus reuteri ZJ616 (JN981858), L. reuteri ZJ617 (JN981859), L. reuteri ZJ621 (JN981863) and L. reuteri ZJ623 (JN981865), showed inhibition against the two pathogens, E. coli K88 and S. enteritidis 50335. L. reuteri ZJ621 showed higher inhibition ability than the others to S. enteritidis 50335 (P S-layer protein, the inhibition activities of the lactobacilli against pathogens decreased significantly (P S-layer proteins plays an important role.

  9. Distribution of cytoskeletal proteins, integrins, leukocyte adhesion molecules and extracellular matrix proteins in plastic-embedded human and rat kidneys

    NARCIS (Netherlands)

    van Goor, H; Coers, W; van der Horst, MLC; Suurmeijer, AJH

    2001-01-01

    OBJECTIVE: To study the distribution of cytoskeletal proteins (actin, alpha -actinin, vinculin, beta -tubulin, keratin, vimentin, desmin), adhesion molecules for cell-matrix interations (very later antigens [VLA1-6], beta1, beta2 [CD18], vitronectin receptor [alphav beta3], CD 11b), leukocyte adhesi

  10. Activation of focal adhesion kinase enhances the adhesion of Fusarium solani to human corneal epithelial cells via the tyrosine-specific protein kinase signaling pathway.

    Science.gov (United States)

    Pan, Xiaojing; Wang, Ye; Zhou, Qingjun; Chen, Peng; Xu, Yuanyuan; Chen, Hao; Xie, Lixin

    2011-03-05

    To determine the role of the integrin-FAK signaling pathway triggered by the adherence of F. solani to human corneal epithelial cells (HCECs). After pretreatment with/without genistein, HCECs were incubated with F. solani spores at different times (0-24 h). Cell adhesion assays were performed by optical microscopy. Changes of the ultrastructure were observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The expression of F-actin and Paxillin (PAX) were detected by immunofluorescence and western blotting to detect the expression of these key proteins with/without genistein treatment. Cell adhesion assays showed that the number of adhered spores began to rise at 6 h after incubation and peaked at 8 h. SEM and TEM showed that the HCECs exhibited a marked morphological alteration induced by the attachment and entry of the spores. The expression of PAX increased, while the expression of F-actin decreased by stimulation with F. solani. The interaction of F. solani with HCECs causes actin rearrangement in HCECs. Genistein strongly inhibited FAK phosphorylation and the activation of the downstream protein (PAX). F. solani-induced enhancement of cell adhesion ability was inhibited along with the inhibition of FAK phosphorylation. Our results suggest that the integrin-FAK signaling pathway is involved in the control of F. solani adhesion to HCECs and that the activation of focal adhesion kinase enhances the adhesion of human corneal epithelial cells to F. solani via the tyrosine-specific protein kinase signaling pathway.

  11. Gecko adhesion pad: a smart surface?

    Science.gov (United States)

    Pesika, Noshir S.; Zeng, Hongbo; Kristiansen, Kai; Zhao, Boxin; Tian, Yu; Autumn, Kellar; Israelachvili, Jacob

    2009-11-01

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  12. Gecko adhesion pad: a smart surface?

    Energy Technology Data Exchange (ETDEWEB)

    Pesika, Noshir S [Chemical and Biomolecular Engineering Department, Tulane University, New Orleans, LA 70118 (United States); Zeng Hongbo [Chemical and Materials Engineering Department, University of Alberta, Edmonton, AB, T6G 2V4 (Canada); Kristiansen, Kai; Israelachvili, Jacob [Chemical Engineering Department, University of California, Santa Barbara, CA 93117 (United States); Zhao, Boxin [Chemical Engineering Department and Waterloo Institute of Nanotechnology, University of Waterloo, Ontario, N2L 3G1 (Canada); Tian Yu [State Key Laboratory of Tribology, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Autumn, Kellar, E-mail: npesika@tulane.ed [Department of Biology, Lewis and Clark College, Portland, OR 97219 (United States)

    2009-11-18

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  13. Gecko adhesion pad: a smart surface?

    Science.gov (United States)

    Pesika, Noshir S; Zeng, Hongbo; Kristiansen, Kai; Zhao, Boxin; Tian, Yu; Autumn, Kellar; Israelachvili, Jacob

    2009-11-18

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  14. Use of soy proteins in polyketone-based wood adhesives

    NARCIS (Netherlands)

    Hamarneh, A.; Heeres, H. J.; Broekhuis, A. A.; Sjollema, K. A.; Zhang, Y.; Picchioni, F.

    2010-01-01

    This paper describes the preparation of aqueous emulsions consisting of soy proteins and chemically modified thermosetting aliphatic polyketones. Emulsions were prepared in a range of total solids contents and different addition protocols were tested. Room temperature stability and structure of the

  15. The modulation of platelet adhesion and activation by chitosan through plasma and extracellular matrix proteins.

    Science.gov (United States)

    Lord, Megan S; Cheng, Bill; McCarthy, Simon J; Jung, MoonSun; Whitelock, John M

    2011-10-01

    Chitosan has been shown to promote initial wound closure events to prevent blood loss. Platelet adhesion and activation are crucial early events in these processes after traumatic bleeding leading to thrombus formation. Platelet adhesion to chitosan was found to be enhanced in the presence of adsorbed plasma and extracellular matrix proteins and was found to be primarily mediated by α(IIb)β(3) integrins, while α(2)β(1) integrins were found to be involved in platelet adhesion to collagen and perlecan. Platelets were found to be activated by chitosan, as shown by an increase in the expression of α(IIb)β(3) integrins and P-selectin, while the extent of activation was modulated by the presence of proteins including perlecan and fibrinogen. Collagen-coated chitosan was found to activate platelets to the same extent as either chitosan or collagen alone. These data support the role of plasma and extracellular matrix proteins in promoting chitosan mediated platelet adhesion and activation supporting the hypothesis that chitosan promotes wound healing via these interactions.

  16. Streptococcal collagen-like surface protein 1 promotes adhesion to the respiratory epithelial cell

    Directory of Open Access Journals (Sweden)

    Chang Cherng-Shyang

    2010-12-01

    Full Text Available Abstract Background Collagen-like surface proteins Scl1 and Scl2 on Streptococcus pyogenes contain contiguous Gly-X-X triplet amino acid motifs, the characteristic structure of human collagen. Although the potential role of Scl1 in adhesion has been studied, the conclusions may be affected by the use of different S. pyogenes strains and their carriages of various adhesins. To explore the bona fide nature of Scl1 in adherence to human epithelial cells without the potential interference of other streptococcal surface factors, we constructed a scl1 isogenic mutant from the Scl2-defective S. pyogenes strain and a Scl1-expressed Escherichia coli. Results Loss of Scl1 in a Scl2-defective S. pyogenes strain dramatically decreased the adhesion of bacteria to HEp-2 human epithelial cells. Expression of Scl1 on the surface of the heterologous bacteria E. coli significantly increased adhesion to HEp-2. The increase in adhesion was nullified when Scl1-expressed E. coli was pre-incubated with proteases or antibodies against recombinant Scl1 (rScl1 protein. Treatment of HEp-2 cells with rScl protein or pronase drastically reduced the binding capability of Scl1-expressed E. coli. These findings suggest that the adhesion is mediated through Scl1 on bacterial surface and protein receptor(s on epithelial cells. Further blocking of potential integrins revealed significant contributions of α2 and β1 integrins in Scl1-mediated binding to epithelial cells. Conclusions Together, these results underscore the importance of Scl1 in the virulence of S. pyogenes and implicate Scl1 as an adhesin during pathogenesis of streptococcal infection.

  17. Writing Inspired

    Science.gov (United States)

    Tischhauser, Karen

    2015-01-01

    Students need inspiration to write. Assigning is not teaching. In order to inspire students to write fiction worth reading, teachers must take them through the process of writing. Physical objects inspire good writing with depth. In this article, the reader will be taken through the process of inspiring young writers through the use of boxes.…

  18. Mechanical and water soaking properties of medium density fiberboard with wood fiber and soybean protein adhesive.

    Science.gov (United States)

    Li, Xin; Li, Yonghui; Zhong, Zhikai; Wang, Donghai; Ratto, Jo A; Sheng, Kuichuan; Sun, Xiuzhi Susan

    2009-07-01

    Soybean protein is a renewable and abundant material that offers an alternative to formaldehyde-based resins. In this study, soybean protein was modified with sodium dodecyl sulfate (SDS) as an adhesive for wood fiber medium density fiberboard (MDF) preparation. Second-order response surface regression models were used to study the effects and interactions of initial moisture content (IMC) of coated wood fiber, press time (PT) and temperature on mechanical and water soaking properties of MDF. Results showed that IMC of coated fiber was the dominant influencing factor. Mechanical and soaking properties improved as IMC increased and reached their highest point at an IMC of 35%. Press time and temperature also had a significant effect on mechanical and water soaking properties of MDF. Second-order regression results showed that there were strong relationships between mechanical and soaking properties of MDF and processing parameters. Properties of MDF made using soybean protein adhesive are similar to those of commercial board.

  19. Distinct biophysical mechanisms of focal adhesion kinase mechanoactivation by different extracellular matrix proteins.

    Science.gov (United States)

    Seong, Jihye; Tajik, Arash; Sun, Jie; Guan, Jun-Lin; Humphries, Martin J; Craig, Susan E; Shekaran, Asha; García, Andrés J; Lu, Shaoying; Lin, Michael Z; Wang, Ning; Wang, Yingxiao

    2013-11-26

    Matrix mechanics controls cell fate by modulating the bonds between integrins and extracellular matrix (ECM) proteins. However, it remains unclear how fibronectin (FN), type 1 collagen, and their receptor integrin subtypes distinctly control force transmission to regulate focal adhesion kinase (FAK) activity, a crucial molecular signal governing cell adhesion/migration. Here we showed, using a genetically encoded FAK biosensor based on fluorescence resonance energy transfer, that FN-mediated FAK activation is dependent on the mechanical tension, which may expose its otherwise hidden FN synergy site to integrin α5. In sharp contrast, the ligation between the constitutively exposed binding motif of type 1 collagen and its receptor integrin α2 was surprisingly tension-independent to induce sufficient FAK activation. Although integrin α subunit determines mechanosensitivity, the ligation between α subunit and the ECM proteins converges at the integrin β1 activation to induce FAK activation. We further discovered that the interaction of the N-terminal protein 4.1/ezrin/redixin/moesin basic patch with phosphatidylinositol 4,5-biphosphate is crucial during cell adhesion to maintain the FAK activation from the inhibitory effect of nearby protein 4.1/ezrin/redixin/moesin acidic sites. Therefore, different ECM proteins either can transmit or can shield from mechanical forces to regulate cellular functions, with the accessibility of ECM binding motifs by their specific integrin α subunits determining the biophysical mechanisms of FAK activation during mechanotransduction.

  20. Adhesion of the human pathogen Sporothrix schenckii to several extracellular matrix proteins

    Directory of Open Access Journals (Sweden)

    O.C. Lima

    1999-05-01

    Full Text Available The pathogenic fungus Sporothrix schenckii is the causative agent of sporotrichosis. This subcutaneous mycosis may disseminate in immunocompromised individuals and also affect several internal organs and tissues, most commonly the bone, joints and lung. Since adhesion is the first step involved with the dissemination of pathogens in the host, we have studied the interaction between S. schenckii and several extracellular matrix (ECM proteins. The binding of two morphological phases of S. schenckii, yeast cells and conidia, to immobilized type II collagen, laminin, fibronectin, fibrinogen and thrombospondin was investigated. Poly (2-hydroxyethyl methacrylate (poly-HEMA was used as the negative control. Cell adhesion was assessed by ELISA with a rabbit anti-S. schenckii antiserum. The results indicate that both morphological phases of this fungus can bind significantly to type II collagen, fibronectin and laminin in comparison to the binding observed with BSA (used as blocking agent. The adhesion rate observed with the ECM proteins (type II collagen, fibronectin and laminin was statistically significant (P<0.05 when compared to the adhesion obtained with BSA. No significant binding of conidia was observed to either fibrinogen or thrombospondin, but yeast cells did bind to the fibrinogen. Our results indicate that S. schenckii can bind to fibronectin, laminin and type II collagen and also show differences in binding capacity according to the morphological form of the fungus.

  1. Surface adhesion of fusion proteins containing the hydrophobins HFBI and HFBII from Trichoderma reesei

    Science.gov (United States)

    Linder, Markus; Szilvay, Geza R.; Nakari-Setälä, Tiina; Söderlund, Hans; Penttilä, Merja

    2002-01-01

    Hydrophobins are surface-active proteins produced by filamentous fungi, where they seem to be ubiquitous. They have a variety of roles in fungal physiology related to surface phenomena, such as adhesion, formation of surface layers, and lowering of surface tension. Hydrophobins can be divided into two classes based on the hydropathy profile of their primary sequence. We have studied the adhesion behavior of two Trichoderma reesei class II hydrophobins, HFBI and HFBII, as isolated proteins and as fusion proteins. Both hydrophobins were produced as C-terminal fusions to the core of the hydrolytic enzyme endoglucanase I from the same organism. It was shown that as a fusion partner, HFBI causes the fusion protein to efficiently immobilize to hydrophobic surfaces, such as silanized glass and Teflon. The properties of the surface-bound protein were analyzed by the enzymatic activity of the endoglucanase domain, by surface plasmon resonance (Biacore), and by a quartz crystal microbalance. We found that the HFBI fusion forms a tightly bound, rigid surface layer on a hydrophobic support. The HFBI domain also causes the fusion protein to polymerize in solution, possibly to a decamer. Although isolated HFBII binds efficiently to surfaces, it does not cause immobilization as a fusion partner, nor does it cause polymerization of the fusion protein in solution. The findings give new information on how hydrophobins function and how they can be used to immobilize fusion proteins. PMID:12192081

  2. OmpA-like protein influences cell shape and adhesive activity of Tannerella forsythia.

    Science.gov (United States)

    Abe, T; Murakami, Y; Nagano, K; Hasegawa, Y; Moriguchi, K; Ohno, N; Shimozato, K; Yoshimura, F

    2011-12-01

    Tannerella forsythia, a gram-negative fusiform rod, is implicated in several types of oral anaerobic infections. Most gram-negative bacteria have OmpA-like proteins that are homologous to the OmpA protein in Escherichia coli. We identified an OmpA-like protein in T. forsythia encoded by the tf1331 gene as one of the major proteins by mass spectrometric analysis. Two-dimensional, diagonal electrophoresis showed that the OmpA-like protein formed a dimeric or trimeric structure via intermolecular disulfide bonds. A biotin labeling experiment revealed that a portion of the protein was exposed on the cell surface, even though T. forsythia possesses an S-layer at the outermost cell surface. Using a tf1331-deletion mutant, we showed that the OmpA-like protein affected cell morphology. The length of the mutant cell was reduced almost by half. Cell swelling was observed in more than 40% of the mutant cells. Moreover, the mutant exhibited decreased adhesion to fibronectin, retarded autoaggregation, and reduced cell surface hydrophobicity. These results suggest that the OmpA-like protein in T. forsythia plays an important role in cellular integrity and adhesive function.

  3. Glycopolymer functionalization of engineered spider silk protein-based materials for improved cell adhesion.

    Science.gov (United States)

    Hardy, John G; Pfaff, André; Leal-Egaña, Aldo; Müller, Axel H E; Scheibel, Thomas R

    2014-07-01

    Silk protein-based materials are promising biomaterials for application as tissue scaffolds, due to their processability, biocompatibility, and biodegradability. The preparation of films composed of an engineered spider silk protein (eADF4(C16)) and their functionalization with glycopolymers are described. The glycopolymers bind proteins found in the extracellular matrix, providing a biomimetic coating on the films that improves cell adhesion to the surfaces of engineered spider silk films. Such silk-based materials have potential as coatings for degradable implantable devices. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Ubiquitous distribution of salts and proteins in spider glue enhances spider silk adhesion

    Science.gov (United States)

    Amarpuri, Gaurav; Chaurasia, Vishal; Jain, Dharamdeep; Blackledge, Todd A.; Dhinojwala, Ali

    2015-03-01

    Modern orb-weaving spiders use micron-sized glue droplets on their viscid silk to retain prey in webs. A combination of low molecular weight salts and proteins makes the glue viscoelastic and humidity responsive in a way not easily achieved by synthetic adhesives. Optically, the glue droplet shows a heterogeneous structure, but the spatial arrangement of its chemical components is poorly understood. Here, we use optical and confocal Raman microscopy to show that salts and proteins are present ubiquitously throughout the droplet. The distribution of adhesive proteins in the peripheral region explains the superior prey capture performance of orb webs as it enables the entire surface area of the glue droplet to act as a site for prey capture. The presence of salts throughout the droplet explains the recent Solid-State NMR results that show salts directly facilitate protein mobility. Understanding the function of individual glue components and the role of the droplet's macro-structure can help in designing better synthetic adhesives for humid environments.

  5. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  6. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  7. Salivary protein adsorption and Streptococccus gordonii adhesion to dental material surfaces.

    Science.gov (United States)

    Schweikl, Helmut; Hiller, Karl-Anton; Carl, Ulrich; Schweiger, Rainer; Eidt, Andreas; Ruhl, Stefan; Müller, Rainer; Schmalz, Gottfried

    2013-10-01

    The initial adhesion of microorganisms to clinically used dental biomaterials is influenced by physico-chemical parameters like hydrophobicity and pre-adsorption of salivary proteins. Here, polymethyl methacrylate (PMMA), polyethylene (PE), polytetrafluoroethylene (PTFE), silicone (Mucopren soft), silorane-based (Filtek Silorane) and methacrylate-based (Tetric EvoCeram) dental composites, a conventional glassionomer cement as well as cobalt-chromium-molybdenum (Co28Cr6Mo) and titanium (Ti6Al4V) were tested for adsorption of salivary proteins and adhesion of Streptococcus gordonii DL1. Wettability of material surfaces precoated with salivary proteins or left in phosphate-buffered saline was determined by the measurement of water contact angles. Amounts of adsorbed proteins were determined directly on material surfaces after biotinylation of amino groups and detection by horseradish peroxidase-conjugated avidin-D. The same technique was used to analyze for the binding of biotinylated bacteria to material surfaces. The highest amount of proteins (0.18μg/cm(2)) adsorbed to hydrophobic PTFE samples, and the lowest amount (0.025μg/cm(2)) was detected on silicone. The highest number of S. gordonii (3.2×10(4)CFU/mm(2)) adhered to the hydrophilic glassionomer cement surface coated with salivary proteins, and the lowest number (4×10(3)CFU/mm(2)) was found on the hydrophobic silorane-based composite. Hydrophobicity of pure material surfaces and the number of attached microorganisms were weakly negatively correlated. No such correlation between hydrophobicity and the number of bacteria was detected when surfaces were coated with salivary proteins. Functional groups added by the adsorption of specific salivary proteins to material surfaces are more relevant for initial bacterial adhesion than hydrophobicity as a physical property. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  8. Mussel-inspired protein-repelling ambivalent block copolymers: controlled synthesis and characterization

    OpenAIRE

    Patil, Nagaraj; Falentin-Daudré, Céline; Jérôme, Christine; Detrembleur, Christophe

    2015-01-01

    This paper describes the reversible addition–fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA) and its implementation to the synthesis of innovative ambivalent block copolymers. They consist of a hydro- phobic poly((meth)acrylamide) block functionalized by catechols and a hydrophilic segment of a poly- ((meth)acrylate) bearing pendent PEG chains. For the first time, a series of well-defined P(PEGAm-b-ADA...

  9. Application of tung oil to improve adhesion strength and water resistance of cottonseed meal and protein adhesives on maple veneer

    Science.gov (United States)

    Cottonseed meal-based products show promise in serving as environment-friendly wood adhesives. However, their practical utilization is currently limited due to low durability and water resistant properties. In this research, we tested the improvement of adhesion strength and water resistance of cott...

  10. Characterization of the in vitro binding and inhibition kinetics of primary amine oxidase/vascular adhesion protein-1 by glucosamine.

    LENUS (Irish Health Repository)

    Olivieri, Aldo

    2012-04-01

    Primary-amine oxidase (PrAO) catalyzes the oxidative deamination of endogenous and exogenous primary amines and also functions, in some tissues, as an inflammation-inducible endothelial factor, known as vascular adhesion protein-1. VAP-1 mediates the slow rolling and adhesion of lymphocytes to endothelial cells in a number of inflammatory conditions, including inflammation of the synovium.

  11. Targeting Protein Kinase C Downstream of Growth Factor and Adhesion Signalling

    Directory of Open Access Journals (Sweden)

    Catríona M. Dowling

    2015-07-01

    Full Text Available The signaling outputs of Receptor Tyrosine Kinases, G-protein coupled receptors and integrins converge to mediate key cell process such as cell adhesion, cell migration, cell invasion and cell proliferation. Once activated by their ligands, these cell surface proteins recruit and direct a diverse range of proteins to disseminate the appropriate response downstream of the specific environmental cues. One of the key groups of proteins required to regulate these activities is the family of serine/threonine intracellular kinases called Protein Kinase Cs. The activity and subcellular location of PKCs are mediated by a series of tightly regulated events and is dependent on several posttranslational modifications and the availability of second messengers. Protein Kinase Cs exhibit both pro- and anti-tumorigenic effects making them an interesting target for anti-cancer treatment.

  12. Targeting Protein Kinase C Downstream of Growth Factor and Adhesion Signalling

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, Catríona M., E-mail: Catriona.Dowling@ul.ie; Kiely, Patrick A., E-mail: Catriona.Dowling@ul.ie [Department of Life Sciences, Materials and Surface Science Institute and Stokes Institute, University of Limerick, Limerick 78666 (Ireland); Health Research Institute (HRI), University of Limerick, Limerick 78666 (Ireland)

    2015-07-15

    The signaling outputs of Receptor Tyrosine Kinases, G-protein coupled receptors and integrins converge to mediate key cell process such as cell adhesion, cell migration, cell invasion and cell proliferation. Once activated by their ligands, these cell surface proteins recruit and direct a diverse range of proteins to disseminate the appropriate response downstream of the specific environmental cues. One of the key groups of proteins required to regulate these activities is the family of serine/threonine intracellular kinases called Protein Kinase Cs. The activity and subcellular location of PKCs are mediated by a series of tightly regulated events and is dependent on several posttranslational modifications and the availability of second messengers. Protein Kinase Cs exhibit both pro- and anti-tumorigenic effects making them an interesting target for anti-cancer treatment.

  13. Endocytosis regulates cell soma translocation and the distribution of adhesion proteins in migrating neurons.

    Directory of Open Access Journals (Sweden)

    Jennifer C Shieh

    Full Text Available Newborn neurons migrate from their birthplace to their final location to form a properly functioning nervous system. During these movements, young neurons must attach and subsequently detach from their substrate to facilitate migration, but little is known about the mechanisms cells use to release their attachments. We show that the machinery for clathrin-mediated endocytosis is positioned to regulate the distribution of adhesion proteins in a subcellular region just proximal to the neuronal cell body. Inhibiting clathrin or dynamin function impedes the movement of migrating neurons both in vitro and in vivo. Inhibiting dynamin function in vitro shifts the distribution of adhesion proteins to the rear of the cell. These results suggest that endocytosis may play a critical role in regulating substrate detachment to enable cell body translocation in migrating neurons.

  14. Lectin receptor kinases participate in protein-protein interactions to mediate plasma membrane-cell wall adhesions in Arabidopsis.

    Science.gov (United States)

    Gouget, Anne; Senchou, Virginie; Govers, Francine; Sanson, Arnaud; Barre, Annick; Rougé, Pierre; Pont-Lezica, Rafael; Canut, Hervé

    2006-01-01

    Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown. Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis (Arabidopsis thaliana), are disrupted by the RGD (arginine-glycine-aspartic acid) tripeptide sequence, a characteristic cell adhesion motif in mammals. In planta induced-O (IPI-O) is an RGD-containing protein from the plant pathogen Phytophthora infestans that can disrupt cell wall-plasma membrane adhesions through its RGD motif. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis. Moreover, the two peptides also disrupted cell wall-plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g60300, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces.

  15. Lectin Receptor Kinases Participate in Protein-Protein Interactions to Mediate Plasma Membrane-Cell Wall Adhesions in Arabidopsis1

    Science.gov (United States)

    Gouget, Anne; Senchou, Virginie; Govers, Francine; Sanson, Arnaud; Barre, Annick; Rougé, Pierre; Pont-Lezica, Rafael; Canut, Hervé

    2006-01-01

    Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown. Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis (Arabidopsis thaliana), are disrupted by the RGD (arginine-glycine-aspartic acid) tripeptide sequence, a characteristic cell adhesion motif in mammals. In planta induced-O (IPI-O) is an RGD-containing protein from the plant pathogen Phytophthora infestans that can disrupt cell wall-plasma membrane adhesions through its RGD motif. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis. Moreover, the two peptides also disrupted cell wall-plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g60300, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces. PMID:16361528

  16. Modulating cell adhesion dynamics on carbon nanotube monolayer engineered with extracellular matrix proteins.

    Science.gov (United States)

    Cai, Ning; Wong, Chee C; Gong, Ying X; Tan, Samuel C W; Chan, Vincent; Liao, Kin

    2010-04-01

    Although it has been demonstrated that carbon nanotubes (CNTs) may have potentials for tissue engineering applications because of their unparalleled physical properties, little has been known on the cell adhesion mechanisms on model CNT monolayer pertaining to the design of novel cell therapeutics device. In this study, the adhesion dynamics of primary porcine esophageal fibroblasts (PEFs) on CNT monolayer were elucidated with confocal reflectance interference contrast microscopy (C-RICM) integrating with phase contrast microscopy. Moreover, CNT monolayer (CNT-ML) was functionalized with two typical extracellular matrix (ECM) proteins including collagen type I (COL) and fibronectin (FN) in order to promote its biocompatibility. First, it is shown by atomic force microscopy that the topographical features of CNT-ML were dependent on the types of immobilized ECM protein. Second, significant time lag in adhesion contact evolution (around 10 min) for PEFs was found on both CNT-ML and CNT-COL compared to the negligible time lag on CNT-FN. It was found that adhesion energy of PEFs on the CNT-COL and CNT-FN surfaces reached steady state at 60 and 30 min after cell seeding compared to 70 min on CNT-ML surface. At steady state, the adhesion energy of PEFs on the CNT-COL and CNT-FN surfaces was about twice as much than that on the CNT-ML surface. Moreover, immobilization of collagen or fibronectin on CNT monolayer led to an increase in seeding efficiency and proliferation rate of PEFs. Scanning electron microscopy and immunostaining together demonstrated that PEFs displayed an elongated morphology and highly polarized actin network on both CNT-COL and CNT-FN surfaces, whereas PEFs displayed nonuniform cell morphology and actin organization on the CNT-ML surface. Overall, our results demonstrated that the biophysical responses and biological behavior of PEFs on unmodified or functionalized CNT monolayer were different. Functionalization of CNT through extracellular matrix

  17. Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions.

    Science.gov (United States)

    Himmel, Mirko; Ritter, Anett; Rothemund, Sven; Pauling, Björg V; Rottner, Klemens; Gingras, Alexandre R; Ziegler, Wolfgang H

    2009-05-15

    In cell-extracellular matrix junctions (focal adhesions), the cytoskeletal protein talin is central to the connection of integrins to the actin cytoskeleton. Talin is thought to mediate this connection via its two integrin, (at least) three actin, and several vinculin binding sites. The binding sites are cryptic in the head-to-rod autoinhibited cytoplasmic form of the protein and require (stepwise) conformational activation. This activation process, however, remains poorly understood, and there are contradictory models with respect to the determinants of adhesion site localization. Here, we report turnover rates and protein-protein interactions in a range of talin rod domain constructs varying in helix bundle structure. We conclude that several bundles of the C terminus cooperate to regulate targeting and concomitantly tailor high affinity interactions of the talin rod in cell adhesions. Intrinsic control of ligand binding activities is essential for the coordination of adhesion site function of talin.

  18. Proteins Play Important Role in Intercellular Adhesion Affecting on Fruit Textural Quality

    DEFF Research Database (Denmark)

    Bahadur Adhikari, Khem; Shomer, Ilan

    2012-01-01

    Fruit textural quality is becoming a major quality parameter for export, postharvest preservation, handling and processing. The main determinant of textural quality is intercellular adhesion (ICA) as attributed by the cell wall (CW) and its components. The importance of CW protein in ICA......H 3.5 ( pKa) incubated fruits (~2 N). The protein bands at ~29 kDa, ~75 kDa, ~32 kDa and 87 kDa were exclusively or prominently found in ICA strengthened fruits (pH 3.5

  19. Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins

    OpenAIRE

    2013-01-01

    In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones t...

  20. Inspired Responses

    Science.gov (United States)

    Steele, Carol Frederick

    2011-01-01

    In terms of teacher quality, Steele believes the best teachers have reached a stage she terms inspired, and that teachers move progressively through the stages of unaware, aware, and capable until the most reflective teachers finally reach the inspired level. Inspired teachers have a wide repertoire of teaching and class management techniques and…

  1. Mapping the dynamics and nanoscale organization of synaptic adhesion proteins using monomeric streptavidin

    Science.gov (United States)

    Chamma, Ingrid; Letellier, Mathieu; Butler, Corey; Tessier, Béatrice; Lim, Kok-Hong; Gauthereau, Isabel; Choquet, Daniel; Sibarita, Jean-Baptiste; Park, Sheldon; Sainlos, Matthieu; Thoumine, Olivier

    2016-01-01

    The advent of super-resolution imaging (SRI) has created a need for optimized labelling strategies. We present a new method relying on fluorophore-conjugated monomeric streptavidin (mSA) to label membrane proteins carrying a short, enzymatically biotinylated tag, compatible with SRI techniques including uPAINT, STED and dSTORM. We demonstrate efficient and specific labelling of target proteins in confined intercellular and organotypic tissues, with reduced steric hindrance and no crosslinking compared with multivalent probes. We use mSA to decipher the dynamics and nanoscale organization of the synaptic adhesion molecules neurexin-1β, neuroligin-1 (Nlg1) and leucine-rich-repeat transmembrane protein 2 (LRRTM2) in a dual-colour configuration with GFP nanobody, and show that these proteins are diffusionally trapped at synapses where they form apposed trans-synaptic adhesive structures. Furthermore, Nlg1 is dynamic, disperse and sensitive to synaptic stimulation, whereas LRRTM2 is organized in compact and stable nanodomains. Thus, mSA is a versatile tool to image membrane proteins at high resolution in complex live environments, providing novel information about the nano-organization of biological structures. PMID:26979420

  2. International Union of Basic and Clinical Pharmacology. XCIV. Adhesion G protein-coupled receptors.

    Science.gov (United States)

    Hamann, Jörg; Aust, Gabriela; Araç, Demet; Engel, Felix B; Formstone, Caroline; Fredriksson, Robert; Hall, Randy A; Harty, Breanne L; Kirchhoff, Christiane; Knapp, Barbara; Krishnan, Arunkumar; Liebscher, Ines; Lin, Hsi-Hsien; Martinelli, David C; Monk, Kelly R; Peeters, Miriam C; Piao, Xianhua; Prömel, Simone; Schöneberg, Torsten; Schwartz, Thue W; Singer, Kathleen; Stacey, Martin; Ushkaryov, Yuri A; Vallon, Mario; Wolfrum, Uwe; Wright, Mathew W; Xu, Lei; Langenhan, Tobias; Schiöth, Helgi B

    2015-01-01

    The Adhesion family forms a large branch of the pharmacologically important superfamily of G protein-coupled receptors (GPCRs). As Adhesion GPCRs increasingly receive attention from a wide spectrum of biomedical fields, the Adhesion GPCR Consortium, together with the International Union of Basic and Clinical Pharmacology Committee on Receptor Nomenclature and Drug Classification, proposes a unified nomenclature for Adhesion GPCRs. The new names have ADGR as common dominator followed by a letter and a number to denote each subfamily and subtype, respectively. The new names, with old and alternative names within parentheses, are: ADGRA1 (GPR123), ADGRA2 (GPR124), ADGRA3 (GPR125), ADGRB1 (BAI1), ADGRB2 (BAI2), ADGRB3 (BAI3), ADGRC1 (CELSR1), ADGRC2 (CELSR2), ADGRC3 (CELSR3), ADGRD1 (GPR133), ADGRD2 (GPR144), ADGRE1 (EMR1, F4/80), ADGRE2 (EMR2), ADGRE3 (EMR3), ADGRE4 (EMR4), ADGRE5 (CD97), ADGRF1 (GPR110), ADGRF2 (GPR111), ADGRF3 (GPR113), ADGRF4 (GPR115), ADGRF5 (GPR116, Ig-Hepta), ADGRG1 (GPR56), ADGRG2 (GPR64, HE6), ADGRG3 (GPR97), ADGRG4 (GPR112), ADGRG5 (GPR114), ADGRG6 (GPR126), ADGRG7 (GPR128), ADGRL1 (latrophilin-1, CIRL-1, CL1), ADGRL2 (latrophilin-2, CIRL-2, CL2), ADGRL3 (latrophilin-3, CIRL-3, CL3), ADGRL4 (ELTD1, ETL), and ADGRV1 (VLGR1, GPR98). This review covers all major biologic aspects of Adhesion GPCRs, including evolutionary origins, interaction partners, signaling, expression, physiologic functions, and therapeutic potential. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Current state and use of biological adhesives in orthopedic surgery.

    Science.gov (United States)

    Shah, Neil V; Meislin, Robert

    2013-12-01

    Bone and tissue adhesives are common and beneficial supplements to standard methods of musculoskeletal tissue suture repair. Knowledge and development of biologically derived or inspired adhesives useful in orthopedic surgery are rapidly advancing. Recent literature demonstrates the increased adjunct or primary use of biological adhesives in the repair of musculoskeletal soft tissues, chondral fractures, and osteochondral fractures. Adhesives offer more benefits and enhancements to tissue healing than current fixation methods afford, including improved biocompatibility, resorbability, and non-immunogenicity. Further investigation is required to determine the extent of the role that these bioadhesives can play in orthopedic surgery. The largest group of biologically derived adhesives and sealants is fibrin sealants, which include first- and second-generation commercially available fibrin sealants, autologous fibrin sealants, and variants. Other groups include gelatin-resorcin aldehydes, protein-aldehyde systems, collagen-based adhesives, polysaccharide- based adhesives, mussel adhesive proteins, and various biologically inspired or biomimetic glues. Potential uses include applications in orthopedic-related blood conservation, arthroplasty, articular cartilage disorders, sports medicine, spine surgery, trauma, and tumors. The development of an adhesive with universal application is likely unfeasible, given the unique characteristics of various musculoskeletal tissues. However, the literature demonstrates the overall underuse of adhesives and indicates the rising probability of the development of a successful variety of bioadhesives for use in orthopedic surgery. As a result of reading this article, physicians should be able to: 1. Describe the difference between adhesives and sealants. 2. Recognize fibrin adhesives commonly used in practice today and identify other biological adhesives with rising potential. 3. Analyze how fibrin sealants work relative to fibrin and

  4. Extracellular Protein Interactions Mediated by the Neural Cell Adhesion Molecule, NCAM: Heterophilic Interactions Between NCAM and Cell Adhesion Molecules, Extracellular Matrix Proteins, and Viruses

    DEFF Research Database (Denmark)

    Nielsen, Janne; Kulahin, Nikolaj; Walmod, Peter

    2008-01-01

    Cell adhesion molecules (CAMs) mediate cell-to-cell interactions and interactions between cells and the extracellular matrix (ECM). The neural cell adhesion molecule (NCAM), a prototypic member of the immunoglobulin (Ig) superfamily of CAMs, mediates adhesion through homophilic and heterophilic i...

  5. Mechanical Activation of a Multimeric Adhesive Protein through Domain Conformational Change

    Science.gov (United States)

    Wijeratne, Sithara S.; Botello, Eric; Yeh, Hui-Chun; Zhou, Zhou; Bergeron, Angela; Frey, Eric W.; Patel, Jay M.; Moake, Joel; Dong, Jing-fei; Kiang, Ching-Hwa

    2013-01-01

    The mechanical force-induced activation of the adhesive protein von Willebrand Factor (VWF), which experiences high hydrodynamic forces, is essential in initiating platelet adhesion. The importance of the mechanical force-induced functional change is manifested in the multimeric VWF’s crucial role in blood coagulation, when high fluid shear stress activates plasma VWF (pVWF) multimers to bind platelets. Here we showed that a pathological level of high shear stress exposure of pVWF multimers results in domain conformational changes, and the subsequent shifts in the unfolding force allow us to use force as a marker to track the dynamic states of multimeric VWF. We found that shear-activated pVWF multimers (spVWF) are more resistant to mechanical unfolding than non-sheared pVWF multimers, as indicated in the higher peak unfolding force. These results provide insight into the mechanism of shear-induced activation of pVWF multimers. PMID:23521301

  6. In Vivo Detection of Vascular Adhesion Protein-1 in Experimental Inflammation

    Science.gov (United States)

    Jaakkola, Kimmo; Nikula, Tuomo; Holopainen, Riikka; Vähäsilta, Tommi; Matikainen, Marja-Terttu; Laukkanen, Marja-Leena; Huupponen, Risto; Halkola, Lauri; Nieminen, Lauri; Hiltunen, Jukka; Parviainen, Sakari; Clark, Michael R.; Knuuti, Juhani; Savunen, Timo; Kääpä, Pekka; Voipio-Pulkki, Liisa Maria; Jalkanen, Sirpa

    2000-01-01

    Vascular adhesion protein-1 (VAP-1) is an inflammation-inducible endothelial glycoprotein which mediates leukocyte-endothelial cell interactions. To study the pathogenetic significance of VAP-1 in inflammatory disorders, an in vivo immunodetection method was used to detect the regulation of luminally expressed VAP-1 in experimental skin and joint inflammation in the pig and dog. Moreover, VAP-1 was studied as a potential target to localize inflammation by radioimmunoscintigraphy. Up-regulation of VAP-1 in experimental dermatitis and arthritis could be visualized by specifically targeted immunoscintigraphy. Moreover, the translocation of VAP-1 to the functional position on the endothelial surface was only seen in inflamed tissues. These results suggest that VAP-1 is both an optimal candidate for anti-adhesive therapy and a potential target molecule for imaging inflammation. PMID:10934150

  7. Flocculation protein structure and cell-cell adhesion mechanism in Saccharomyces cerevisiae.

    Science.gov (United States)

    Goossens, Katty; Willaert, Ronnie

    2010-11-01

    Cell-cell adhesion occurs in a broad spectrum of biological processes, of which yeast flocculation is an area of interest for evolutionary scientists to brewers and winemakers. The flocculation mechanism is based on a lectin-carbohydrate interaction but is not yet fully understood, although the first model dates back to the 1950s. This review will update the current understanding of the complex mechanism behind yeast flocculation. Moreover, modern technologies to measure the forces involved in single carbohydrate-lectin interactions, are discussed. The Flo1 protein has been extensively described as the protein responsible for strong flocculation. Recently, more research has been directed to the detailed analysis of this flocculin. Due to the advances in the field of bioinformatics, more information about Flo1p could be obtained via structurally or functionally related proteins. Here, we review the current knowledge of the Flo1 protein, with a strong emphasis towards its structure.

  8. Expression profile of the entire family of Adhesion G protein-coupled receptors in mouse and rat

    Directory of Open Access Journals (Sweden)

    Ebendal Ted

    2008-04-01

    Full Text Available Abstract Background The Adhesion G protein-coupled receptors (GPCRs are membrane-bound receptors with long N termini. This family has 33 members in humans. Several Adhesion GPCRs are known to have important physiological functions in CNS development and immune system response mediated by large cell surface ligands. However, the majority of Adhesion GPCRs are still poorly studied orphans with unknown functions. Results In this study we performed the extensive tissue localization analysis of the entire Adhesion GPCR family in rat and mouse. By applying the quantitative real-time PCR technique we have produced comparable expression profile for each of the members in the Adhesion family. The results are compared with literature data and data from the Allen Brain Atlas project. Our results suggest that the majority of the Adhesion GPCRs are either expressed in the CNS or ubiquitously. In addition the Adhesion GPCRs from the same phylogenetic group have either predominant CNS or peripheral expression, although each of their expression profile is unique. Conclusion Our findings indicate that many of Adhesion GPCRs are expressed, and most probably, have function in CNS. The related Adhesion GPCRs are well conserved in their structure and interestingly have considerable overlap in their expression profiles, suggesting similarities among the physiological roles for members within many of the phylogenetically related clusters.

  9. Aire knockdown in medullary thymic epithelial cells affects Aire protein, deregulates cell adhesion genes and decreases thymocyte interaction.

    Science.gov (United States)

    Pezzi, Nicole; Assis, Amanda Freire; Cotrim-Sousa, Larissa Cotrim; Lopes, Gabriel Sarti; Mosella, Maritza Salas; Lima, Djalma Sousa; Bombonato-Prado, Karina F; Passos, Geraldo Aleixo

    2016-09-01

    We demonstrate that even a partial reduction of Aire mRNA levels by siRNA-induced Aire knockdown (Aire KD) has important consequences to medullary thymic epithelial cells (mTECs). Aire knockdown is sufficient to reduce Aire protein levels, impair its nuclear location, and cause an imbalance in large-scale gene expression, including genes that encode cell adhesion molecules. These genes drew our attention because adhesion molecules are implicated in the process of mTEC-thymocyte adhesion, which is critical for T cell development and the establishment of central self-tolerance. Accordingly, we consider the following: 1) mTECs contribute to the elimination of self-reactive thymocytes through adhesion; 2) Adhesion molecules play a crucial role during physical contact between these cells; and 3) Aire is an important transcriptional regulator in mTECs. However, its role in controlling mTEC-thymocyte adhesion remains unclear. Because Aire controls adhesion molecule genes, we hypothesized that the disruption of its expression could influence mTEC-thymocyte interaction. To test this hypothesis, we used a murine Aire(+) mTEC cell line as a model system to reproduce mTEC-thymocyte adhesion in vitro. Transcriptome analysis of the mTEC cell line revealed that Aire KD led to the down-modulation of more than 800 genes, including those encoding for proteins involved in cell adhesion, i.e., the extracellular matrix constituent Lama1, the CAM family adhesion molecules Vcam1 and Icam4, and those that encode peripheral tissue antigens. Thymocytes co-cultured with Aire KD mTECs had a significantly reduced capacity to adhere to these cells. This finding is the first direct evidence that Aire also plays a role in controlling mTEC-thymocyte adhesion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. WHEY PROTEIN-BASED WATER RESISTANT AND ENVIRONMENTALLY SAFE ADHESIVES FOR PLYWOOD

    Directory of Open Access Journals (Sweden)

    Zongyan Zhao

    2011-06-01

    Full Text Available Whey protein is a renewable and environmentally safe biomaterial, a by-product of cheese production. It can be utilized for non-food applications for value-added products. The substances glyoxal (GO, glutaraldehyde (GA, polymeric methylene biphenyl diisocyanate (p-MDI, urea-formaldehyde (UF resin, and phenol-formaldehyde oligomer (PFO that contain reactive groups were applied together with whey protein as modifier in order to increase crosslinking density and molecular weight for improving the bond strength and water resistance of whey protein. A water-resistant and environmentally safe whey protein-based wood adhesive for plywood was developed by evaluating the effects of these modifiers on the bond strength, bond durability, and free formaldehyde emission of the resulting plywood panels. Results of FTIR and SEM analyses and bond evaluation indicated that GO, GA, and p-MDI were not suitable to modify whey proteins due to their high reactivity with whey proteins, causing phase separation. UF resin was not a good modifier for whey proteins because of either its poor water-resistance or higher emission of hazardous formaldehyde. Whey protein adhesives modified with PFO had a dry shear bond strength of 1.98 MPa and a 28h-boiling-dry-boiling wet shear strength of 1.73 MPa, which were both much higher than the required values for structural use according to standard JIS K6806-2003, while its formaldehyde emission was 0.067mg/L, much lower than the required value for green plywood according to standard JIS A5908.

  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 (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. TiO2 nanotubes functionalized with regions of bone morphogenetic protein-2 increases osteoblast adhesion.

    Science.gov (United States)

    Balasundaram, Ganesan; Yao, Chang; Webster, Thomas J

    2008-02-01

    Titanium (Ti) and its alloys are widely used in orthopedic and dental applications. However, the native TiO2 layer is not bioactive enough to form a direct bond with bone, which sometimes translates into a lack of osseointegration into juxtaposed bone that might lead to long term implant failure. In this study, the 20 amino acid peptide sequence (the so-called "knuckle epitope") of bone morphogenetic protein-2 (BMP-2) was immobilized onto Ti nanotubes created by electrochemical anodization. Further, human osteoblast (bone-forming cell) responses to such anodic Ti oxides functionalized with the BMP-2 knuckle epitope was examined in vitro. Materials were characterized by scanning electron and atomic force microscopy. Results of this in vitro study continued to provide evidence of increased osteoblast adhesion on Ti anodized to possess nanotubes compared to unanodized Ti. However, for the first time, results also showed that the immobilization of the BMP-2 knuckle epitope onto Ti anodized to possess nanotubes increased osteoblast adhesion compared to non-functionalized anodized Ti, anodized Ti functionalized with amine (NH2) groups, and unanodized Ti after 4 h. Results also showed increased osteoblast adhesion on amine terminated anodized Ti compared to respective non-functionalized anodized Ti and unanodized Ti. In summary, results of this in vitro study provided evidence that Ti anodized to possess nanotubes and then further functionalized with the BMP-2 knuckle epitope should be further studied for improved orthopedic applications.

  13. Adhesion of Candida albicans to various dental implant surfaces and the influence of salivary pellicle proteins.

    Science.gov (United States)

    Bürgers, Ralf; Hahnel, Sebastian; Reichert, Torsten E; Rosentritt, Martin; Behr, Michael; Gerlach, Till; Handel, Gerhard; Gosau, Martin

    2010-06-01

    Dental implants may be considered a potential reservoir for (re)infection with oral Candida albicans. Our aim was to evaluate initial fungal adhesion to three differentially textured titanium and one zirconia implant surface, and to correlate these findings to differences in specific surface characteristics (surface roughness (R(a)) and surface free energy (SFE)). Additionally, we investigated the influence of salivary protein films and two pellicle proteins (mucin and albumin). Implant surfaces were characterized by perthometer (R(a)) and goniometer (SFE) measurements. Implant specimens were rinsed with human whole saliva, mucin, albumin, or phosphate buffered saline and incubated in C. albicans suspension for 2.5h. Adherent fungi were quantified by means of a bioluminometric assay. The lowest amount of fungal cells was found on sand-blasted titanium, whereas zirconia implants did not show any reduced potential to adhere C. albicans. The influence of the implant SFE on fungal biofilm formation appears to be more important than the influence of R(a). The protein mucin enhanced C. albicans accumulation. In contrast, albumin is unlikely to be involved in the adhesion process of C. albicans. Copyright 2010. Published by Elsevier Ltd.

  14. A multidomain adhesion protein family expressed in Plasmodium falciparum is essential for transmission to the mosquito.

    Science.gov (United States)

    Pradel, Gabriele; Hayton, Karen; Aravind, L; Iyer, Lakshminarayan M; Abrahamsen, Mitchell S; Bonawitz, Annemarie; Mejia, Cesar; Templeton, Thomas J

    2004-06-07

    The recent sequencing of several apicomplexan genomes has provided the opportunity to characterize novel antigens essential for the parasite life cycle that might lead to the development of new diagnostic and therapeutic markers. Here we have screened the Plasmodium falciparum genome sequence for genes encoding extracellular multidomain putative adhesive proteins. Three of these identified genes, named PfCCp1, PfCCp2, and PfCCp3, have multiple adhesive modules including a common Limulus coagulation factor C domain also found in two additional Plasmodium genes. Orthologues were identified in the Cryptosporidium parvum genome sequence, indicating an evolutionary conserved function. Transcript and protein expression analysis shows sexual stage-specific expression of PfCCp1, PfCCp2, and PfCCp3, and cellular localization studies revealed plasma membrane-associated expression in mature gametocytes. During gametogenesis, PfCCps are released and localize surrounding complexes of newly emerged microgametes and macrogametes. PfCCp expression markedly decreased after formation of zygotes. To begin to address PfCCp function, the PfCCp2 and PfCCp3 gene loci were disrupted by homologous recombination, resulting in parasites capable of forming oocyst sporozoites but blocked in the salivary gland transition. Our results describe members of a conserved apicomplexan protein family expressed in sexual stage Plasmodium parasites that may represent candidates for subunits of a transmission-blocking vaccine.

  15. Amigo Adhesion Protein Regulates Development of Neural Circuits in Zebrafish Brain*

    Science.gov (United States)

    Zhao, Xiang; Kuja-Panula, Juha; Sundvik, Maria; Chen, Yu-Chia; Aho, Vilma; Peltola, Marjaana A.; Porkka-Heiskanen, Tarja; Panula, Pertti; Rauvala, Heikki

    2014-01-01

    The Amigo protein family consists of three transmembrane proteins characterized by six leucine-rich repeat domains and one immunoglobulin-like domain in their extracellular moieties. Previous in vitro studies have suggested a role as homophilic adhesion molecules in brain neurons, but the in vivo functions remain unknown. Here we have cloned all three zebrafish amigos and show that amigo1 is the predominant family member expressed during nervous system development in zebrafish. Knockdown of amigo1 expression using morpholino oligonucleotides impairs the formation of fasciculated tracts in early fiber scaffolds of brain. A similar defect in fiber tract development is caused by mRNA-mediated expression of the Amigo1 ectodomain that inhibits adhesion mediated by the full-length protein. Analysis of differentiated neural circuits reveals defects in the catecholaminergic system. At the behavioral level, the disturbed formation of neural circuitry is reflected in enhanced locomotor activity and in the inability of the larvae to perform normal escape responses. We suggest that Amigo1 is essential for the development of neural circuits of zebrafish, where its mechanism involves homophilic interactions within the developing fiber tracts and regulation of the Kv2.1 potassium channel to form functional neural circuitry that controls locomotion. PMID:24904058

  16. Focal Adhesion Kinase Regulates Expression of Thioredoxin-interacting Protein (TXNIP) in Cancer Cells

    OpenAIRE

    2014-01-01

    Focal Adhesion Kinase (FAK) plays an important role in cancer cell survival. Previous microarray gene profiling study detected inverse regulation between expression of thioredoxin-interacting protein (TXNIP) and FAK, where down-regulation of FAK by siRNA in MCF-7 cells caused up-regulation of TXNIP mRNA level, and in contrast up-regulation of doxycyclin- induced FAK caused repression of TXNIP. In the present report, we show that overexpression of FAK in MCF-7 cells repressed TXNIP promoter ac...

  17. Molekulare Charakterisierung und Identifizierung eines Aktivierungsmechanismus von Adhesion-G-Protein-gekoppelten Rezeptoren

    OpenAIRE

    Schön, Julia

    2015-01-01

    Die Familie der Adhesion-G-Protein-gekoppelten Rezeptoren (aGPCR) stellt die zweitgrößte Gruppe der GPCR dar. Ein strukturelles Charakteristikum der aGPCR ist der modular aufgebaute N-Terminus, welcher eine GPCR-proteolytic site (GPS) mit einem konservierten Spaltungsmotiv enthält. Trotz der hohen medizinischen Relevanz dieser Rezeptorgruppe sind für die meisten der 33 humanen Vertreter der aGPCR bis heute weder Funktion noch endogener Agonist bekannt. Um sie jedoch zukünftig als potentielle ...

  18. Micro patterning of cell and protein non-adhesive plasma polymerized coatings for biochip applications

    DEFF Research Database (Denmark)

    Bouaidat, Salim; Berendsen, C.; Thomsen, P.;

    2004-01-01

    Micro scale patterning of bioactive surfaces is desirable for numerous biochip applications. Polyethyleneoxide-like (PEO-like) coating with non-fouling functionality has been deposited using low frequency AC plasma polymerization. The non-fouling properties of the coating were tested with human...... cells ( HeLa) and fluorescence labeled proteins (isothiocyanate-labeled bovine serum albumin, i.e. FITC-BSA). The PEO-like coatings were fabricated by plasma polymerization of 12-crown-4 (ppCrown) with plasma polymerized hexene (ppHexene) as adhesion layer. The coatings were micro patterned using...

  19. Stainless steel modified with poly(ethylene glycol) can prevent protein adsorption but not bacterial adhesion

    DEFF Research Database (Denmark)

    Wei, Jiang; Bagge, Dorthe; Gram, Lone

    2003-01-01

    The surface of AISI 316 grade stainless steel (SS) was modified with a layer of poly(ethylene glycol) (PEG) (molecular weight 5000) with the aim of preventing protein adsorption and bacterial adhesion. Model SS substrates were first modified to introduce a very high density of reactive amine groups...... by the adsorption of branched poly(ethylenimine) (PEI) from water. Methoxy-terminated aldehyde-poly(ethylene glycol) (M-PEG-CHO) was then grafted onto the PEI layers using reductive amination at the lower critical solution temperature (LCST) of the PEG in order to optimize the graft density of the linear PEG chains...

  20. Protein micro patterned lattices to probe a fundamental lengthscale involved in cell adhesion

    CERN Document Server

    Guillou, Herve; Chaussy, Jacques; Block, Marc R

    2009-01-01

    Cell adhesion, a fundamental process of cell biology is involved in the embryo development and in numerous pathologies especially those related to cancers. We constrained cells to adhere on extracellular matrix proteins patterned in a micro lattices. The actin cytoskeleton is particularly sensitive to this constraint and reproducibly self organizes in simple geometrical patterns. Such highly organized cells are functional and proliferate. We performed statistical analysis of spread cells morphologies and discuss the existence of a fundamental lengthscale associated with active processes required for spreading.

  1. Recombinant Probiotic Expressing Listeria Adhesion Protein Attenuates Listeria monocytogenes Virulence In Vitro

    Science.gov (United States)

    Koo, Ok Kyung; Amalaradjou, Mary Anne Roshni; Bhunia, Arun K.

    2012-01-01

    Background Listeria monocytogenes, an intracellular foodborne pathogen, infects immunocompromised hosts. The primary route of transmission is through contaminated food. In the gastrointestinal tract, it traverses the epithelial barrier through intracellular or paracellular routes. Strategies to prevent L. monocytogenes entry can potentially minimize infection in high-risk populations. Listeria adhesion protein (LAP) aids L. monocytogenes in crossing epithelial barriers via the paracellular route. The use of recombinant probiotic bacteria expressing LAP would aid targeted clearance of Listeria from the gut and protect high-risk populations from infection. Methodology/Principal Findings The objective was to investigate the ability of probiotic bacteria or LAP-expressing recombinant probiotic Lactobacillus paracasei (LbpLAP) to prevent L. monocytogenes adhesion, invasion, and transwell-based transepithelial translocation in a Caco-2 cell culture model. Several wild type probiotic bacteria showed strong adhesion to Caco-2 cells but none effectively prevented L. monocytogenes infection. Pre-exposure to LbpLAP for 1, 4, 15, or 24 h significantly (Pmonocytogenes in Caco-2 cells, whereas pre-exposure to parental Lb. paracasei had no significant effect. Similarly, LbpLAP pre-exposure reduced L. monocytogenes translocation by as much as 46% after 24 h. LbpLAP also prevented L. monocytogenes-mediated cell damage and compromise of tight junction integrity. Furthermore, LbpLAP cells reduced L. monocytogenes-mediated cell cytotoxicity by 99.8% after 1 h and 79% after 24 h. Conclusions/Significance Wild type probiotic bacteria were unable to prevent L. monocytogenes infection in vitro. In contrast, LbpLAP blocked adhesion, invasion, and translocation of L. monocytogenes by interacting with host cell receptor Hsp60, thereby protecting cells from infection. These data show promise for the use of recombinant probiotics in preventing L. monocytogenes infection in high

  2. Amyloid precursor-like protein 1 (APLP1) exhibits stronger zinc-dependent neuronal adhesion than amyloid precursor protein and APLP2.

    Science.gov (United States)

    Mayer, Magnus C; Schauenburg, Linda; Thompson-Steckel, Greta; Dunsing, Valentin; Kaden, Daniela; Voigt, Philipp; Schaefer, Michael; Chiantia, Salvatore; Kennedy, Timothy E; Multhaup, Gerhard

    2016-04-01

    The amyloid precursor protein (APP) and its paralogs, amyloid precursor-like protein 1 (APLP1) and APLP2, are metalloproteins with a putative role both in synaptogenesis and in maintaining synapse structure. Here, we studied the effect of zinc on membrane localization, adhesion, and secretase cleavage of APP, APLP1, and APLP2 in cell culture and rat neurons. For this, we employed live-cell microscopy techniques, a microcontact printing adhesion assay and ELISA for protein detection in cell culture supernatants. We report that zinc induces the multimerization of proteins of the amyloid precursor protein family and enriches them at cellular adhesion sites. Thus, zinc facilitates the formation of de novo APP and APLP1 containing adhesion complexes, whereas it does not have such influence on APLP2. Furthermore, zinc-binding prevented cleavage of APP and APLPs by extracellular secretases. In conclusion, the complexation of zinc modulates neuronal functions of APP and APLPs by (i) regulating formation of adhesion complexes, most prominently for APLP1, and (ii) by reducing the concentrations of neurotrophic soluble APP/APLP ectodomains. Earlier studies suggest a function of the amyloid precursor protein (APP) family proteins in neuronal adhesion. We report here that adhesive function of these proteins is tightly regulated by zinc, most prominently for amyloid precursor-like protein 1 (APLP1). Zinc-mediated APLP1 multimerization, which induced formation of new neuronal contacts and decreased APLP1 shedding. This suggests that APLP1 could function as a zinc receptor processing zinc signals to stabilized or new neuronal contacts.

  3. Surface modification of diamond-like carbon films with protein via polydopamine inspired coatings

    Science.gov (United States)

    Tao, Caihong; Yang, Shengrong; Zhang, Junyan; Wang, Jinqing

    2009-10-01

    In this paper, we report a facile two-step approach to immobilize proteins onto DLC surfaces. The first step was a simple immersion of DLC in a solution of dopamine. Polydopamine was deposited on DLC as a stable anchor to present protein molecules. Then the protein ad-layer was deposited on it. The chemical components of the modified DLC surfaces were characterized by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The biocompatibility of it was evaluated in vitro by the tetrazolium salt method. And it was indicated that the BSA modified surface had good haemocompatibility properties, and was cytocompatible to PC-12 cells.

  4. Surface modification of diamond-like carbon films with protein via polydopamine inspired coatings

    Energy Technology Data Exchange (ETDEWEB)

    Tao Caihong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); China and Graduate University of Chinese Academy of Sciences, Beijing 100080 (China); Yang Shengrong [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); Zhang Junyan, E-mail: zhangjunyan@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China); Wang Jinqing [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Tianshui Middle Road 18th, Lanzhou 730000 (China)

    2009-10-15

    In this paper, we report a facile two-step approach to immobilize proteins onto DLC surfaces. The first step was a simple immersion of DLC in a solution of dopamine. Polydopamine was deposited on DLC as a stable anchor to present protein molecules. Then the protein ad-layer was deposited on it. The chemical components of the modified DLC surfaces were characterized by Fourier transform infrared spectra and X-ray photoelectron spectroscopy. The biocompatibility of it was evaluated in vitro by the tetrazolium salt method. And it was indicated that the BSA modified surface had good haemocompatibility properties, and was cytocompatible to PC-12 cells.

  5. Mussel-inspired adhesive and transferable free-standing films by self-assembling dexamethasone encapsulated BSA nanoparticles and vancomycin immobilized oxidized alginate.

    Science.gov (United States)

    Han, Lu; Wang, Zhen-ming; Lu, Xiong; Dong, Li; Xie, Chao-ming; Wang, Ke-feng; Chen, Xiao-lang; Ding, Yong-hui; Weng, Lu-tao

    2015-02-01

    This study developed an adhesive and transferable free-standing (FS) film with dual function of osteoinductivity and antibacterial activity, which was obtained by sequentially assembling vancomycin immobilized oxidized sodium alginate and dexamethasone encapsulated chitosan coated BSA nanoparticles on a poly-dopamine layer. The FS films enabled the dual release of vancomycin and dexamethasone. The FS films had excellent osteoinductivity and antibacterial activity by cell culture and antibacterial assay. The FS film was detached from substrates and transferred to non-fouling surfaces by a wet transfer method, which demonstrated that the adhesive FS film is potential to modify biopolymers with non-fouling surfaces in mild and biocompatible conditions for biomedical applications.

  6. Focal adhesion kinase regulates expression of thioredoxin-interacting protein (TXNIP) in cancer cells.

    Science.gov (United States)

    Ho, Baotran; Huang, Grace; Golubovskaya, Vita M

    2014-01-01

    Focal Adhesion Kinase (FAK) plays an important role in cancer cell survival. Previous microarray gene profiling study detected inverse regulation between expression of thioredoxin-interacting protein (TXNIP) and FAK, where down-regulation of FAK by siRNA in MCF-7 cells caused up-regulation of TXNIP mRNA level, and in contrast up-regulation of doxycyclin- induced FAK caused repression of TXNIP. In the present report, we show that overexpression of FAK in MCF-7 cells repressed TXNIP promoter activity. Treatment of MCF-7 cells with 1alpha, 25-dihydroxyvitamin D3 (1,25D) down-regulated endogenous FAK and up-regulated TXNIP protein level, and treatment with 5-FU decreased FAK protein expression and up-regulated TXNIP protein expression in 293 cells. Moreover, silencing of FAK with siRNA increased TXNIP protein expression, while overexpression of FAK inhibited TXNIP protein expression in 293 cells. In addition, treatment of DBTRG glioblastoma cells with FAK inhibitor Y15 increased TXNIP mRNA, decreased cancer cell viability and increased apoptosis. These results for the first time demonstrate FAK-regulated TXNIP expression which is important for apoptotic, survival and oxidative stress signaling pathways in cancer cells.

  7. Sensitivity of protein adsorption to architectural variations in a protein-resistant polymer brush containing engineered nanoscale adhesive sites.

    Science.gov (United States)

    Gon, Saugata; Santore, Maria M

    2011-12-20

    Patchy polymer brushes contain nanoscale (5-15 nm) adhesive elements, such as polymer coils or nanoparticles, embedded at their base at random positions on the surface. The competition between the brush's steric (protein resistant) repulsions and the attractions from the discrete adhesive elements provides a precise means to control bioadhesion. This differs from the classical approach, where functionality is placed on the brush's periphery. The current study demonstrates the impact of poly(etheylene glycol) (PEG) brush architecture and ionic strength on fibrinogen adsorption on brushes containing embedded poly-l-lysine (PLL, 20K MW) coils or "patches". The consistent appearance of a fibrinogen adsorption threshold, a minimum loading of patches on the surface, below which protein adsorption does not occur, suggests multivalent protein capture: Adsorbing proteins simultaneously engage several patches. The surface composition (patch loading) at the threshold is extremely sensitive to the brush height and ionic strength, varying up to a factor of 5 in the surface loading of the PLL patches (~50% of the range of possible surfaces). Variations in ionic strength have a similar effect, with the smallest thresholds seen for the largest Debye lengths. While trends with brush height were the clearest and most dominant, consideration of the PEG loading within the brush or its persistence length did not reveal a critical brush parameter for the onset of adsorption. The lack of straightforward correlation on brush physics was likely a result of multivalent binding, (producing an additional dependence on patch loading), and might be resolved for univalent adsorption onto more strongly binding patches. While studies with similar brushes placed uniformly on a surface revealed that the PEG loading within the brush is the best indicator of protein resistance, the current results suggest that brush height is more important for patchy brushes. Likely the interactions producing brush

  8. Regulator of G protein signaling 20 enhances cancer cell aggregation, migration, invasion and adhesion.

    Science.gov (United States)

    Yang, Lei; Lee, Maggie M K; Leung, Manton M H; Wong, Yung H

    2016-11-01

    Several RGS (regulator of G protein signaling) proteins are known to be upregulated in a variety of tumors but their roles in modulating tumorigenesis remain undefined. Since the expression of RGS20 is elevated in metastatic melanoma and breast tumors, we examined the effects of RGS20 overexpression and knockdown on the cell mobility and adhesive properties of different human cancer cell lines, including cervical cancer HeLa, breast adenocarcinoma MDA-MB-231, and non-small cell lung carcinoma H1299 and A549 cells. Expression of RGS20 enhanced cell aggregation, migration, invasion and adhesion as determined by hanging drop aggregation, wound healing, transwell chamber migration and invasion assays. Conversely, shRNA-mediated knockdown of endogenous RGS20 impaired these responses. In addition, RGS20 elevated the expression of vimentin (a mesenchymal cell marker) but down-regulated the expression of E-cadherin, two indicators commonly associated with metastasis. These results suggest that the expression of RGS20 may promote metastasis of tumor cells.

  9. Non-leaching antimicrobial surfaces through polydopamine bio-inspired coating of quaternary ammonium salts or an ultrashort antimicrobial lipopeptide.

    OpenAIRE

    Shalev, Tel; Gopin, Anna; Bauer, Michael; Stark, Robert W.; Rahimipour, Shai

    2012-01-01

    Bacterial fouling on surfaces significantly increases the resistance of bacteria toward antibiotics, which leads to medical complications and a corresponding financial burden. Here, we report on a general and robust technique for facile modification of various surfaces with different antibacterial agents. Our approach in this study was inspired by the strong adhesion of mussel adhesion proteins (MAPs) to many types of surfaces, including metals, polymers, and inorganic materials. Thus, glass ...

  10. A standardized bamboo leaf extract inhibits monocyte adhesion to endothelial cells by modulating vascular cell adhesion protein-1.

    Science.gov (United States)

    Choi, Sunga; Park, Myoung Soo; Lee, Yu Ran; Lee, Young Chul; Kim, Tae Woo; Do, Seon-Gil; Kim, Dong Seon; Jeon, Byeong Hwa

    2013-02-01

    Bamboo leaves (Phyllostachys pubescens Mazel ex J. Houz (Poacea)) have a long history of food and medical applications in Asia, including Japan and Korea. They have been used as a traditional medicine for centuries. We investigated the mechanism of anti-inflammatory activity of a bamboo leaf extract (BLE) on tumor necrosis factor-alpha (TNF-α)-induced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to BLE did not inhibit cell viability or cause morphological changes at concentrations ranging from 1 µg/ml to 1 mg/ml. Treatment with 0.1 mg/ml BLE caused 63% inhibition of monocyte adhesion in TNF-α-activated HUVECs, which was associated with 38.4% suppression of vascular cell adhesion molecule-1 expression. Furthermore, TNF-α-induced reactive oxygen species generation was decreased to 47.9% in BLE treated TNF-α-activated HUVECs. BLE (0.05 mg/ml) also caused about 50% inhibition of interleukin-6 secretion from lipopolysaccharide-stimulated monocyte. The results indicate that BLE may be clinically useful as an anti-inflammatory or anti-oxidant for human cardiovascular disease including atherosclerosis.

  11. Platelet adhesion and protein adsorption on silicone rubber surface by ozone-induced grafted polymerization with carboxybetaine monomer.

    Science.gov (United States)

    Zhou, Jun; Yuan, Jiang; Zang, Xiaopeng; Shen, Jian; Lin, Sicong

    2005-03-10

    Platelet adhesion and protein adsorption on the silicone rubber film grafted with N,N'-dimethyl-N-methacryloyloxyethyl-N-(2-carboxyethyl) ammonium (DMMCA) was studied. The grafting was carried out by means of ozone-induced method and was confirmed by ATR-FTIR and XPS investigations. The grafted films possessed relatively hydrophilic surface revealed by contact angle measurement. The blood compatibility of the grafted film was evaluated in vitro by platelet adhesion in platelet-rich plasma (PRP) and protein absorption in bovine fibrinogen (BFG) using silicone film as the reference. No substantial platelet adhesion was observed for the grafted films incubated in PRP for 60 and 180 min. The protein absorption was also significantly reduced after incubated in bovine fibrinogen for 60 min. Both the results indicated that the blood compatibility of silicone rubber was greatly improved by ozone-induced grafting of carboxybetaine zwitterionic polymer onto its surface.

  12. Proteomic analysis of α4β1 integrin adhesion complexes reveals α-subunit-dependent protein recruitment

    Science.gov (United States)

    Byron, Adam; Humphries, Jonathan D; Craig, Sue E; Knight, David; Humphries, Martin J

    2012-01-01

    Integrin adhesion receptors mediate cell–cell and cell–extracellular matrix interactions, which control cell morphology and migration, differentiation, and tissue integrity. Integrins recruit multimolecular adhesion complexes to their cytoplasmic domains, which provide structural and mechanosensitive signaling connections between the extracellular and intracellular milieux. The different functions of specific integrin heterodimers, such as α4β1 and α5β1, have been attributed to distinct signal transduction mechanisms that are initiated by selective recruitment of adhesion complex components to integrin cytoplasmic tails. Here, we report the isolation of ligand-induced adhesion complexes associated with wild-type α4β1 integrin, an activated α4β1 variant in the absence of the α cytoplasmic domain (X4C0), and a chimeric α4β1 variant with α5 leg and cytoplasmic domains (α4Pα5L), and the cataloguing of their proteomes by MS. Using hierarchical clustering and interaction network analyses, we detail the differential recruitment of proteins and highlight enrichment patterns of proteins to distinct adhesion complexes. We identify previously unreported components of integrin adhesion complexes and observe receptor-specific enrichment of molecules with previously reported links to cell migration and cell signaling processes. Furthermore, we demonstrate colocalization of MYO18A with active integrin in migrating cells. These datasets provide a resource for future studies of integrin receptor-specific signaling events. PMID:22623428

  13. Composite hydrogels of bio-inspired protein polymers : mechanical and structural characterization

    NARCIS (Netherlands)

    Rombouts, W.H.

    2015-01-01

    In this thesis we presented various combinations of custom-designed protein polymers that formed composite hydrogels. In chapter 2, composite hydrogels were prepared by mixing silk-like block copolymers (CP2SE48CP2) with collagen-like block copolymers (T9CR4T9). We found that by add

  14. Finding Inspiration in the Protein Data Bank to Chemically Antagonize Readers of the Histone Code.

    Science.gov (United States)

    Campagna-Slater, Valérie; Schapira, Matthieu

    2010-04-12

    Members of the Royal family of proteins are readers of the histone code that contain aromatic cages capable of recognizing specific sequences and lysine methylation states on histone tails. These binding modules play a key role in epigenetic signalling, and are part of a larger group of epigenetic targets that are becoming increasingly attractive for drug discovery. In the current study, pharmacophore representations of the aromatic cages forming the methyl-lysine (Me-Lys) recognition site were used to search the Protein Data Bank (PDB) for ligand binding pockets possessing similar chemical and geometrical features in unrelated proteins. The small molecules bound to these sites were then extracted from the PDB, and clustered based on fragments binding to the aromatic cages. The compounds collected are numerous and structurally diverse, but point to a limited set of preferred chemotypes; these include quaternary ammonium, sulfonium, and primary, secondary and tertiary amine moieties, as well as aromatic, aliphatic or orthogonal rings, and bicyclic systems. The chemical tool-kit identified can be used to design antagonists of the Royal family and related proteins. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Composite hydrogels of bio-inspired protein polymers : mechanical and structural characterization

    NARCIS (Netherlands)

    Rombouts, W.H.

    2015-01-01

    In this thesis we presented various combinations of custom-designed protein polymers that formed composite hydrogels. In chapter 2, composite hydrogels were prepared by mixing silk-like block copolymers (CP2SE48CP2) with collagen-like block copolymers (T9CR4T9). We found that by

  16. Redistribution of microfilament-associated proteins during the formation of focal contacts and adhesions in chick fibroblasts

    DEFF Research Database (Denmark)

    Couchman, J R; Badley, R A; Rees, D A

    1983-01-01

    fibroblast system which initially has no such adhesion specializations but then develops them sequentially over a 48 h period. Without exception, all focal contacts and focal adhesions contain both vinculin and alpha-actinin at every stage that we can detect by IRM or by double staining to reveal...... the associated microfilament bundles. Indeed the appearance of small bodies containing alpha-actinin and vinculin is shown to precede focal contact formation in our model system and such structures (not visible by IRM) are proposed to be the precursors of focal contacts and adhesions. Myosin and filamin......The roles of the microfilament-associated proteins vinculin, alpha-actinin, myosin and filamin have been studied by immunofluorescence and double fluorescence in conjunction with interference reflection microscopy (IRM), during the development of focal contacts and focal adhesions in a chick...

  17. Identification of novel splice variants of Adhesion G protein-coupled receptors.

    Science.gov (United States)

    Bjarnadóttir, Thóra K; Geirardsdóttir, Kristín; Ingemansson, Malena; Mirza, Majd A I; Fredriksson, Robert; Schiöth, Helgi B

    2007-01-31

    Alternative splicing is an important mechanism to generate proteome diversity in higher eukaryotic organisms. We searched for splice variants of the human Adhesion family of G protein-coupled receptors (GPCRs) using mRNA sequences and expressed sequence tags. The results presented here describe 53 human splice variants among the 33 Adhesion GPCRs. Many of these variants appear to be coding for "functional" proteins (29) while the others are seemingly "non-functional" (24). Novel functional splice variants were found for: CD97, CELR3, EMR2, EMR3, GPR56, GPR110, GPR112-GPR114, GPR116, GPR123-GPR126, GPR133, HE6, and LEC1-LEC3. Splice variants for GPR116, GPR125, GPR126, and HE6 were found conserved in other species. Several of the functional splice variants lack one or more of the functional domains that are found in the N-termini of these receptors. These functional domains are likely to affect ligand binding or interaction with other proteins and these novel splice variants may have important roles for the specificity of interactions between these receptors and extracellular molecules. Another type of splice variants found here lacks a GPCR proteolytic site (GPS). The GPS domain has been shown to be essential for the proteolytic cleavage of the receptors N-termini and for cellular surface expression. We suggest that these alternative splice variants may be crucial for the function of the receptors while the seemingly non-functional splice variants may be a part of a regulative mechanism.

  18. Atomic-accuracy prediction of protein loop structures through an RNA-inspired Ansatz.

    Directory of Open Access Journals (Sweden)

    Rhiju Das

    Full Text Available Consistently predicting biopolymer structure at atomic resolution from sequence alone remains a difficult problem, even for small sub-segments of large proteins. Such loop prediction challenges, which arise frequently in comparative modeling and protein design, can become intractable as loop lengths exceed 10 residues and if surrounding side-chain conformations are erased. Current approaches, such as the protein local optimization protocol or kinematic inversion closure (KIC Monte Carlo, involve stages that coarse-grain proteins, simplifying modeling but precluding a systematic search of all-atom configurations. This article introduces an alternative modeling strategy based on a 'stepwise ansatz', recently developed for RNA modeling, which posits that any realistic all-atom molecular conformation can be built up by residue-by-residue stepwise enumeration. When harnessed to a dynamic-programming-like recursion in the Rosetta framework, the resulting stepwise assembly (SWA protocol enables enumerative sampling of a 12 residue loop at a significant but achievable cost of thousands of CPU-hours. In a previously established benchmark, SWA recovers crystallographic conformations with sub-Angstrom accuracy for 19 of 20 loops, compared to 14 of 20 by KIC modeling with a comparable expenditure of computational power. Furthermore, SWA gives high accuracy results on an additional set of 15 loops highlighted in the biological literature for their irregularity or unusual length. Successes include cis-Pro touch turns, loops that pass through tunnels of other side-chains, and loops of lengths up to 24 residues. Remaining problem cases are traced to inaccuracies in the Rosetta all-atom energy function. In five additional blind tests, SWA achieves sub-Angstrom accuracy models, including the first such success in a protein/RNA binding interface, the YbxF/kink-turn interaction in the fourth 'RNA-puzzle' competition. These results establish all-atom enumeration as

  19. Platelet adhesion and plasma protein adsorption control of collagen surfaces by He{sup +} ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Kurotobi, K. E-mail: kurotobi@postman.riken.go.jp; Suzuki, Y.; Nakajima, H.; Suzuki, H.; Iwaki, M

    2003-05-01

    He{sup +} ion implanted collagen-coated tubes with a fluence of 1 x 10{sup 14} ions/cm{sup 2} were exhibited antithrombogenicity. To investigate the mechanisms of antithrombogenicity of these samples, plasma protein adsorption assay and platelet adhesion experiments were performed. The adsorption of fibrinogen (Fg) and von Willebrand factor (vWf) was minimum on the He{sup +} ion implanted collagen with a fluence of 1 x 10{sup 14} ions/cm{sup 2}. Platelet adhesion (using platelet rich plasma) was inhibited on the He{sup +} ion implanted collagen with a fluence of 1 x 10{sup 14} ions/cm{sup 2} and was accelerated on the untreated collagen and ion implanted collagen with fluences of 1 x 10{sup 13}, 1 x 10{sup 15} and 1 x 10{sup 16} ions/cm{sup 2}. Platelet activation with washed platelets was observed on untreated collagen and He{sup +} ion implanted collagen with a fluence of 1 x 10{sup 14} ions/cm{sup 2} and was inhibited with fluences of 1 x 10{sup 13}, 1 x 10{sup 15} and 1 x 10{sup 16} ions/cm{sup 2}. Generally, platelets can react with a specific ligand inside the collagen (GFOGER sequence). The results of platelets adhesion experiments using washed platelets indicated that there were no ligands such as GFOGER on the He{sup +} ion implanted collagen over a fluence of 1 x 10{sup 13} ions/cm{sup 2}. On the 1 x 10{sup 14} ions/cm{sup 2} implanted collagen, no platelet activation was observed due to the influence of plasma proteins. >From the above, it is concluded that the decrease of adsorbed Fg and vWf caused the antithrombogenicity of He{sup +} ion implanted collagen with a fluence of 1 x 10{sup 14} ions/cm{sup 2} and that plasma protein adsorption took an important role repairing the graft surface.

  20. Anterior gradient protein-2 is a regulator of cellular adhesion in prostate cancer.

    Directory of Open Access Journals (Sweden)

    Diptiman Chanda

    Full Text Available Anterior Gradient Protein (AGR-2 is reported to be over-expressed in many epithelial cancers and promotes metastasis. A clear-cut mechanism for its observed function(s has not been previously identified. We found significant upregulation of AGR-2 expression in a bone metastatic prostate cancer cell line, PC3, following culturing in bone marrow-conditioned medium. Substantial AGR-2 expression was also confirmed in prostate cancer tissue specimens in patients with bone lesions. By developing stable clones of PC3 cells with varying levels of AGR-2 expression, we identified that abrogation of AGR-2 significantly reduced cellular attachment to fibronectin, collagen I, collagen IV, laminin I and fibrinogen. Loss of cellular adhesion was associated with sharp decrease in the expression of α4, α5, αV, β3 and β4 integrins. Failure to undergo apoptosis following detachment is a hallmark of epithelial cancer metastasis. The AGR-2-silenced PC3 cells showed higher resistance to Tumor necrosis factor-related apoptosis- inducing ligand (TRAIL induced apoptosis in vitro. This observation was also supported by significantly reduced Caspase-3 expression in AGR-2-silenced PC3 cells, which is a key effector of both extrinsic and intrinsic death signaling pathways. These data suggest that AGR-2 influence prostate cancer metastasis by regulation of cellular adhesion and apoptosis.

  1. Functional roles of mannose-binding protein in the adhesion, cytotoxicity and phagocytosis of Acanthamoeba castellanii.

    Science.gov (United States)

    Kim, Jong-Hyun; Matin, Abdul; Shin, Ho-Joon; Park, Hyun; Yoo, Kyung-Tae; Yuan, Xi-Zhe; Kim, Kwang Sik; Jung, Suk-Yul

    2012-10-01

    Acanthamoeba castellanii is a single-celled protozoan that is widely distributed in the environment and is a well-known of causing human keratitis, a vision-threatening infection. In this study, an ethyl methane sulfonate (EMS) and a selection of saccharide were applied to A. castellanii by chemical mutagenesis. To understand the functional roles of a mannose-binding protein (MBP). A. castellanii were treated with methyl-alpha-D-mannopyranoside abbreviated Man, with and without the EMS pre-treatment, and their adhesion and cytotoxicity were analyzed, using a human brain microvascular endothelial cell (HBMEC) as the target cell. Both EMS and Man mutants exhibited significantly decreased levels of MBP expression and cytotoxicity to HBMEC, but showed similar levels of binding to HBMEC, as compared with the wild type. Of interest was that the exogenous mannose inhibited amoebae (i.e., Man mutant) binding to the HBMEC by <20%. Only the mutant Man exhibited a significant decrease in bacterial uptake, as compared to the wild type, 0.020 vs 0.032 (p<0.05) and proteolytic activity. The results showed that MBP should be clearly provided as the pathogenic target candidate, to further target-based therapy, but EMS mutation should not be associated with initial adhesion and phagocytosis of A. castellanii.

  2. Direct covalent coupling of proteins to nanostructured plasma polymers: a route to tunable cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Melnichuk, Iurii, E-mail: iurii.melnichuk@gmail.com [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); Choukourov, Andrei, E-mail: choukourov@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); Bilek, Marcela, E-mail: m.bilek@physics.usyd.edu.au [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); School of Physics, University of Sydney, NSW 2006 (Australia); Weiss, Anthony, E-mail: tony.weiss@sydney.edu.au [School of Molecular Bioscience, University of Sydney, NSW 2006 (Australia); Vandrovcová, Marta, E-mail: Marta.Vandrovcova@fgu.cas.cz [Institute of Physiology of Czech Academy of Science, Prague 14220 (Czech Republic); Bačáková, Lucie, E-mail: Lucie.Bacakova@fgu.cas.cz [Institute of Physiology of Czech Academy of Science, Prague 14220 (Czech Republic); Hanuš, Jan, E-mail: jan.hanus@gmail.com [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); Kousal, Jaroslav, E-mail: jarda@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); Shelemin, Artem, E-mail: artem.shelemin@gmail.com [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); Solař, Pavel, E-mail: pawell.solar@seznam.cz [Charles University in Prague, Faculty of Mathematics and Physics, Department of Macromolecular Physics, Prague 18000 (Czech Republic); and others

    2015-10-01

    Highlights: • Flat and nanostructured interfaces were overcoated by hydrocarbon plasma polymer. • Linker-free covalent attachment of proteins to resultant surfaces was validated. • Ultra-thin hydrocarbon overcoat (<2 nm) secured prolonged effective binding. • Pre-adsorbed tropoelastin promoted proliferation of osteoblast-like MG-63 cells. • Nanostructured films were multi-affine and impeded cell adhesion. - Abstract: Flat and nanostructured thin films were fabricated by deposition of ultra-thin (<2 nm) layer of hydrocarbon plasma polymer over polished silicon and over a pattern of 8 nm-thick poly(ethylene) islands on silicon. Linker-free radical-based covalent binding of bovine serum albumin and tropoelastin was confirmed for both types of films. The binding capability of albumin was found to be stable over many days of ambient air storage time. Tropoelastin-mediated flat plasma polymers favored adhesion and proliferation of osteoblast-like MG-63 cells. Nanostructured plasma polymers were multi-affine and their hierarchical surface represented an additional barrier for cell attachment.

  3. Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins

    Science.gov (United States)

    Dobrowsky, Terrence M.; Rabi, S. Alireza; Nedellec, Rebecca; Daniels, Brian R.; Mullins, James I.; Mosier, Donald E.; Siliciano, Robert F.; Wirtz, Denis

    2013-10-01

    In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones to tensile strengths of the individual Env-receptor bonds of Env proteins obtained from a HIV-1 infected patient prior to and during coreceptor switching. The results suggest that the genetic determinants of viral entry were predominantly enriched in the C3, HR1 and CD regions rather than V3. Env proteins can better mediate entry into cells after coreceptor switch; this effective entry capacity does not correlate with the bond strengths between viral Env and cellular receptors.

  4. Adhesion and fusion efficiencies of human immunodeficiency virus type 1 (HIV-1) surface proteins.

    Science.gov (United States)

    Dobrowsky, Terrence M; Rabi, S Alireza; Nedellec, Rebecca; Daniels, Brian R; Mullins, James I; Mosier, Donald E; Siliciano, Robert F; Wirtz, Denis

    2013-10-22

    In about half of patients infected with HIV-1 subtype B, viral populations shift from utilizing the transmembrane protein CCR5 to CXCR4, as well as or instead of CCR5, during late stage progression of the disease. How the relative adhesion efficiency and fusion competency of the viral Env proteins relate to infection during this transition is not well understood. Using a virus-cell fusion assay and live-cell single-molecule force spectroscopy, we compare the entry competency of viral clones to tensile strengths of the individual Env-receptor bonds of Env proteins obtained from a HIV-1 infected patient prior to and during coreceptor switching. The results suggest that the genetic determinants of viral entry were predominantly enriched in the C3, HR1 and CD regions rather than V3. Env proteins can better mediate entry into cells after coreceptor switch; this effective entry capacity does not correlate with the bond strengths between viral Env and cellular receptors.

  5. The adhesion of mussel foot protein-3 to TiO2 surfaces: the effect of pH

    Science.gov (United States)

    Yu, Jing; Wei, Wei; Menyo, Matthew S.; Masic, Admir; Waite, J. Herbert; Israelachvili, Jacob N.

    2013-01-01

    The underwater adhesion of marine mussels relies on mussel foot proteins (mfps) rich in the catecholic amino acid 3, 4-dihydroxyphenylalanine (Dopa). As a side-chain, Dopa is capable of strong bidentate interactions with a variety of surfaces, including many minerals and metal oxides. Titanium is among the most widely used medical implant material and quickly forms a TiO2 passivation layer under physiological conditions. Understanding the binding mechanism of Dopa to TiO2 surfaces is therefore of considerable theoretical and practical interest. Using a surface forces apparatus, we explored the force-distance profiles and adhesion energies of mussel foot protein 3 (mfp-3) to TiO2 surfaces at three different pHs (pH3, 5.5 and 7.5). At pH3, mfp-3 showed the strongest adhesion force on TiO2, with an adhesion energy of ~ −7.0 mJ/m2. Increasing the pH gives rise to two opposing effects: (1) increased oxidation of Dopa, thus decreasing availability for the Dopa-mediated adhesion, and (2) increased bidentate Dopa-Ti coordination, leading to the further stabilization of the Dopa group and thus an increasing of adhesion force. Both effects were reflected in the resonance-enhanced Raman spectra obtained at the three deposition pHs. The two competing effects give rise to a higher adhesion force of mfp-3 on TiO2 surface at pH 7.5 than at pH 5.5. Our results suggest that Dopa-containing proteins and synthetic polymers have great potential as coating materials for medical implant materials, particularly if redox activity can be controlled. PMID:23452271

  6. Accelerating Inspire

    CERN Document Server

    AUTHOR|(CDS)2266999

    2017-01-01

    CERN has been involved in the dissemination of scientific results since its early days and has continuously updated the distribution channels. Currently, Inspire hosts catalogues of articles, authors, institutions, conferences, jobs, experiments, journals and more. Successful orientation among this amount of data requires comprehensive linking between the content. Inspire has lacked a system for linking experiments and articles together based on which accelerator they were conducted at. The purpose of this project has been to create such a system. Records for 156 accelerators were created and all 2913 experiments on Inspire were given corresponding MARC tags. Records of 18404 accelerator physics related bibliographic entries were also tagged with corresponding accelerator tags. Finally, as a part of the endeavour to broaden CERN's presence on Wikipedia, existing Wikipedia articles of accelerators were updated with short descriptions and links to Inspire. In total, 86 Wikipedia articles were updated. This repo...

  7. Adsorption and adhesion of blood proteins and fibroblasts on multi-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    LI Dedun; YUAN Li; YANG Ying; DENG XiangYun; Lü XiaoYing; HUANG Yan; CAO Zheng; LIU Hao; SUN XueLiang

    2009-01-01

    This article concerns the investigation of blood protein adsorption on carbon paper and multi-wall carbon nanotubes (MWCNTs). Mouse fibroblast cell adhesion and growth on MWCNTs was also studied. The results showed that fibrinogen adsorption on carbon paper was much lower than that on MWCNTs, which means that platelets readily aggregate on the surface of MWCNTs. Mouse fibroblast cells im-planted on MWCNTs tended to grow more prolifically than those implanted on carbon paper. The cell concentration observed on MWCNTs increased from 1.2×105/mL for a single day culture to 2×105/mL for a 7-day culture. No toxicity reaction was observed during the culturing period. These results indi-cated that MWCNTs possessed excellent tissue compatibility.

  8. Adsorption and adhesion of blood proteins and fibroblasts on multi-wall carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    This article concerns the investigation of blood protein adsorption on carbon paper and multi-wall carbon nanotubes (MWCNTs). Mouse fibroblast cell adhesion and growth on MWCNTs was also studied. The results showed that fibrinogen adsorption on carbon paper was much lower than that on MWCNTs, which means that platelets readily aggregate on the surface of MWCNTs. Mouse fibroblast cells implanted on MWCNTs tended to grow more prolifically than those implanted on carbon paper. The cell concentration observed on MWCNTs increased from 1.2×105/mL for a single day culture to 2×105/mL for a 7-day culture. No toxicity reaction was observed during the culturing period. These results indicated that MWCNTs possessed excellent tissue compatibility.

  9. Facile immobilization of heparin on bioabsorbable iron via mussel adhesive protein (MAPs

    Directory of Open Access Journals (Sweden)

    Xuchen Xu

    2014-10-01

    Full Text Available Motivated by adhesive proteins in mussels, strategies using dopamine to modified surface have become particularly attractive. In the present work, we developed a novel and convenient method to modify the biodegradable Fe plates with heparin. Iron was first treated by a facile one-step pH-induced polymerization of dopamine, and then a high density heparin was successfully grafted onto the surface via coupling with polydopamine (PDA active layer. Heparin immobilization contributed much longer blood clotting coagulation time than the pure Fe sample, and hence reduced the risk of thrombosis. Cell viability tests suggested that the heparin modified Fe plates were more favorable to the proliferation of ECV304 cells. In summary, the heparin modified Fe plates with good anti-thrombus properties and inhibiting the proliferation of VSMC cells provide great prospects for biodegradable iron.

  10. Facile immobilization of heparin on bioabsorbable iron via mussel adhesive protein (MAPs)

    Institute of Scientific and Technical Information of China (English)

    Xuchen Xu; Ming Li; Qian Liu; Zhaojun Jia; Yuying Shi; Yan Cheng; Yufeng Zheng; L.Q. Ruan

    2014-01-01

    Motivated by adhesive proteins in mussels, strategies using dopamine to modified surface have become particularly attractive. In the present work, we developed a novel and convenient method to modify the biodegradable Fe plates with heparin. Iron was first treated by a facile one-step pH-induced polymerization of dopamine, and then a high density heparin was successfully grafted onto the surface via coupling with polydopamine (PDA) active layer. Heparin immobilization contributed much longer blood clotting coagulation time than the pure Fe sample, and hence reduced the risk of thrombosis. Cell viability tests suggested that the heparin modified Fe plates were more favorable to the proliferation of ECV304 cells. In summary, the heparin modified Fe plates with good anti-thrombus properties and inhibiting the proliferation of VSMC cells provide great prospects for biodegradable iron.

  11. A mutant form of the rho protein can restore stress fibers and adhesion plaques in v-src transformed fibroblasts.

    Science.gov (United States)

    Mayer, T; Meyer, M; Janning, A; Schiedel, A C; Barnekow, A

    1999-03-25

    The organization of polymerized actin in the mammalian cell is regulated by several members of the rho family. Three rho proteins, cdc42, rac and rho act in a cascade to organize the intracellular actin cytoskeleton. Rho proteins are involved in the formation of actin stress fibers and adhesion plaques in fibroblasts. During transformation of mammalian cells by oncogenes the cytoskeleton is rearranged and stress fibers and adhesion plaques are disintegrated. In this paper we investigate the function of the rho protein in RR1022 rat fibroblasts transformed by the Rous sarcoma virus. Two activated mutants of the rho protein, rho G14V and rho Q63L, and a dominant negative mutant, rho N1171, were stably transfected into RR1022 cells. The resulting cell lines were analysed for the organization of polymerized actin and adhesion plaques. Cells expressing rho Q63L, but not rho wt, rho G14V or rho N1171, showed an altered morphology. These cells displayed a flat, fibroblast like shape when compared with the RR1022 ancestor cells. Immunofluorescence analyses revealed that actin stress fibers and adhesion plaques were rearranged in these cells. We conclude from these data that an active rho protein can restore elements of the actin cytoskeleton in transformed cells by overriding the tyrosine kinase phosphorylation induced by the pp60(v-src).

  12. Effect of anticoagulants on the protein corona-induced reduced drug carrier adhesion efficiency in human blood flow.

    Science.gov (United States)

    Sobczynski, Daniel J; Eniola-Adefeso, Omolola

    2017-01-15

    Plasma proteins rapidly coat the surfaces of particulate drug carriers to form a protein corona upon their injection into the bloodstream. The high presence of immunoglobulins in the corona formed on poly(lactic-co-glycolic acid) (PLGA) vascular-targeted carrier (VTC) surfaces was recently shown to negatively impact their adhesion to activated endothelial cells (aECs) in vitro. Here, we characterized the influence of anticoagulants, or their absence, on the binding efficiency of VTCs of various materials via modulation of their protein corona. Specifically, we evaluated the adhesion of PLGA, poly(lactic acid) (PLA), polycaprolactone (PCL), silica, and polystyrene VTCs to aECs in heparinized, citrated, and non-anticoagulated (serum and whole) blood flows relative to buffer control. Particle adhesion is substantially reduced in non-anticoagulated blood flows regardless of the material type while only moderate to minimal reduction is observed for VTCs in anticoagulant-containing blood flow depending on the anticoagulant and material type. The substantial reduction in VTC adhesion in blood flows was linked to a high presence of immunoglobulin-sized proteins in the VTC corona via SDS-PAGE analysis. Of all the materials evaluated, PLGA was the most sensitive to plasma protein effects while PCL was the most resistant, suggesting particle hydrophobicity is a critical component of the observed negative plasma protein effects. Overall, this work demonstrates that anticoagulant positively alters the effect of plasma proteins in prescribing VTC adhesion to aECs in human blood flow, which has implication in the use of in vitro blood flow assays for functional evaluation of VTCs for in vivo use.

  13. E-selectin ligand-1 (ESL-1) is a novel adiponectin binding protein on cell adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Hiroyasu; Kuroda, Nana; Uekita, Hiromi; Kochi, Ikoi; Matsumoto, Akane; Niinaga, Ryu [Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka (Japan); Funahashi, Tohru; Shimomura, Iichiro [Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka (Japan); Kihara, Shinji, E-mail: skihara@sahs.med.osaka-u.ac.jp [Department of Biomedical Informatics, Division of Health Sciences, Osaka University Graduate School of Medicine, Osaka (Japan)

    2016-02-05

    Background: Adiponectin (APN) is an adipocyte-derived bioactive molecule with anti-diabetic and anti-atherogenic properties. Although anti-diabetic effects are mostly mediated by the adiponectin receptors AdipoR1 and AdipoR2, the anti-atherogenic mechanisms have not been fully elucidated. Methods and Results: In this study, we identified E-selectin ligand (ESL)-1 as a novel APN-binding protein by mass spectrometry analysis of HepG2 cell-derived immunoprecipitant with an anti-APN antibody. Cell adhesion assays using fluorescence-labelled monocyte cell line THP-1 cells and human umbilical vein endothelial cells (HUVECs) revealed that APN-pre-treated THP-1 cells had reduced binding ability to HUVECs. This APN-mediated suppressive effect on monocyte binding to endothelial cells was partially abrogated by targeting ESL-1 with shRNA in THP-1 cells. In addition, serial mutagenesis analysis disclosed that five extracellular amino acids close to the N-terminus of ESL-1 were essential for binding with APN. Conclusion: Our results highlight the fact that interaction between APN and ESL-1 could provide a fundamental mechanism underlying the anti-atherogenic properties of APN. - Highlights: • E-selectin ligand (ESL)-1 was identified as an adiponectin (APN)-binding protein. • ESL-1 bound to APN at its N-terminal 6th-10th amino acids. • shESL-1 reduced the suppressive effect of APN on adhesion of THP-1 cells to HUVECs. • Interaction with ESL may be involved in the anti-atherogenic effects of APN.

  14. Protein Modifiers Generally Provide Limited Improvement in Wood Bond Strength of Soy Flour Adhesives

    Science.gov (United States)

    Charles R. Frihart; Linda Lorenz

    2013-01-01

    Soy flour adhesives using a polyamidoamine-epichlorohydrin (PAE) polymeric coreactant are used increasingly as wood adhesives for interior products. Although these adhesives give good performance, higher bond strength under wet conditions is desirable. Wet strength is important for accelerated tests involving the internal forces generated by the swelling of wood and...

  15. Effect of dispersion method and CNT loading on the quality and performance of nanocomposite soy protein/CNTs adhesive for wood application

    Science.gov (United States)

    Afolabi, Ayo Samuel; Oluwafolakemi Sadare, Olawumi; Olawale Daramola, Michael

    2016-09-01

    In this article the effect of dispersion method and carbon nanotubes (CNTs) loading on the quality and performance of a nanocomposite adhesive is reported. The nanocomposite soy protein isolate adhesive was successfully developed by incorporating CNTs into the soy protein isolate (SPI) for enhanced bond strength and water resistance. Dispersion methods, namely mechanical (shear) mixing and mechanical/sonication were employed to aid good dispersion and interfacial interaction between soy protein matrix and the carbon nanofillers during the preparation of the adhesive. The concentration of the CNT was varied from 0.1-0.7 wt% in the nanocomposite adhesive. The morphology and the surface chemistry of the adhesives were checked with SEM and FTIR, respectively. The shear strength of the developed adhesives was investigated according to European standard (EN-204) for interior wood application on a tensile testing machine. The morphological structure of the nanocomposite adhesive obtained from SEM images showed homogeneous dispersion of CNTs in SPI using the two dispersion methods; shear mixing and sonication/shear mixing. Fourier transform infrared spectra showed chemical functionalities and successful interaction between CNTs and SPI adhesive. Thermogravimetric profile of the adhesive samples showed that the newly developed nanocomposite adhesive was thermally stable at a temperature up to about 600 °C at a higher percentage loading of 0.5 wt% CNTs. The result showed that sonication method of dispersion of CNTs into the SPI adhesive had a higher shear strength compared to the mechanical method of dispersion both at dry and wet state.

  16. Mussel inspired protein-mediated surface functionalization of electrospun nanofibers for pH-responsive drug delivery

    Science.gov (United States)

    Jiang, Jiang; Xie, Jingwei; Ma, Bing; Bartlett, David E.; Xu, An; Wang, Chi-Hwa

    2014-01-01

    pH-responsive drug delivery systems could mediate drug releasing rate by changing pH values at specific time as per the pathophysiological need of the disease. Herein, we demonstrated a mussel inspired protein polydopamine coating can tune the loading and releasing rate of charged molecules from electrospun poly (ε-caprolactone) (PCL) nanofibers in solutions with different pH values. In vitro release profiles showed that the positive charged molecules released significantly faster in acidic than those in neutral and basic environments within the same incubation time. The results of fluorescein diacetate staining and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed the viability of cancer cells after treatment with doxorubicin released media at different pH values qualitatively and quantitatively, indicating the media contained doxorubicin which was released in solutions at low pH values could kill significantly higher number of cells than that released in solutions at high pH values. Together, the pH-responsive drug delivery systems based on polydopamine-coated PCL nanofibers could have potential applications in oral delivery of anticancer drugs for treating gastric cancer and vaginal delivery of anti-viral drugs or anti-inflammatory drugs, which could raise their efficacy, deliver them to the specific target, and minimize their toxic side effects. PMID:24287161

  17. Diamagnetic levitation causes changes in the morphology, cytoskeleton, and focal adhesion proteins expression in osteocytes.

    Science.gov (United States)

    Qian, A R; Wang, L; Gao, X; Zhang, W; Hu, L F; Han, J; Li, J B; Di, S M; Shang, Peng

    2012-01-01

    Diamagnetic levitation technology is a novel simulated weightless technique and has recently been applied in life-science research. We have developed a superconducting magnet platform with large gradient high magnetic field (LG-HMF), which can provide three apparent gravity levels, namely, μg (diamagnetic levitation), 1g, and 2g for diamagnetic materials. In this study, the effects of LG-HMF on the activity, morphology, and cytoskeleton (actin filament, microtubules, and vimentin intermediate filaments) in osteocyte - like cell line MLO-Y4 were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) methods, hematoxylin-eosin (HE) staining, and laser scanning confocal microscopy (LSCM), respectively. The changes induced by LG-HMF in distribution and expression of focal adhesion (FA) proteins, including vinculin, paxillin, and talin in MLO-Y4 were determined by LSCM and Western blotting. The results showed that LG-HMF produced by superconducting magnet had no lethal effects on MLO-Y4. Compared to control, diamagnetic levitation (μg) affected MLO-Y4 morphology, nucleus size, cytoskeleton architecture, and FA proteins distribution and expression. The study indicates that osteocytes are sensitive to altered gravity and FA proteins (vinculin, paxillin, and talin) may be involved in osteocyte mechanosensation. The diamagnetic levitation may be a novel ground-based space-gravity simulator and can be used for biological experiment at cellular level. © 2011 IEEE

  18. Medium-density particleboards from modified rice husks and soybean protein concentrate-based adhesives.

    Science.gov (United States)

    Ciannamea, Emiliano M; Stefani, Pablo M; Ruseckaite, Roxana A

    2010-01-01

    The main goal of this work was to evaluate the technical feasibility of using rice husk (RH) as wood substitute in the production of environmentally sound medium-density particleboards using adhesives from soybean protein concentrate (SPC). Chemical modification of rice husk with sodium hydroxide and sodium hydroxide followed by hydrogen peroxide (bleaching) were undertaken to evaluate the effect of such treatments on the composition and topology of rice husk and the performance of produced panels. Both treatments were efficient in partially eliminating hemicelluloses, lignin and silica from RH, as evidenced by thermo-gravimetric analysis (TGA). Scanning electron microscopy observations suggested that alkaline treatment resulted in a more damaged RH substrate than bleaching. The dependence of mechanical properties (modulus of rupture, modulus of elasticity, and internal bond) and the physical properties (water absorption and thickness swelling) on chemical treatments performed on both, rice husk and SPC was studied. Bleached-rice husk particleboards bonded with alkaline-treated soybean protein concentrate displayed the best set of final properties. Particleboards with this formulation met the minimum requirements of internal bond, modulus of elasticity and modulus of rupture recommended by the US Standard ANSI/A208.1 specifications for M1, MS and M2-grade medium-density particleboards, but failed to achieve the thickness swelling value recommended for general use panels. This limitation of soybean protein concentrate-bonded rice husk particleboards was counterbalanced by the advantage of being formaldehyde-free which makes them a suitable alternative for indoor applications.

  19. The recognition of adsorbed and denatured proteins of different topographies by β2 integrins and effects on leukocyte adhesion and activation

    DEFF Research Database (Denmark)

    Brevig, T.; Holst, B.; Ademovic, Z.

    2005-01-01

    Leukocyte beta(2) integrins Mac-1 and p150,95 are promiscuous cell-surface receptors that recognise and mediate cell adhesion to a variety of adsorbed and denatured proteins. We used albumin as a model protein to study whether leukocyte adhesion and activation depended on the nm-scale topography ...

  20. Surface-modified nanoparticles as a new, versatile, and mechanically robust nonadhesive coating: Suppression of protein adsorption and bacterial adhesion

    NARCIS (Netherlands)

    Holmes, P.F.; Currie, E.P.K.; Thies, J.C.; Mei, van der H.C.; Busscher, H.J.; Norde, W.

    2009-01-01

    The synthesis of surface-modified silica nanoparticles, chemically grafted with acrylate and poly(ethylene glycol) (PEG) groups, and the ability of the resulting crosslinked coatings to inhibit protein adsorption and bacterial adhesion are explored. Water contact angles, nanoindentation, and atomic

  1. Surface-modified nanoparticles as a new, versatile, and mechanically robust nonadhesive coating : Suppression of protein adsorption and bacterial adhesion

    NARCIS (Netherlands)

    Holmes, P. F.; Currie, E. P. K.; Thies, J. C.; van der Mei, H. C.; Busscher, H. J.; Norde, W.

    2009-01-01

    The synthesis of surface-modified silica nanoparticles, chemically grafted with acrylate and poly(ethylene glycol) (PEG) groups, and the ability of the resulting crosslinked coatings to inhibit protein adsorption and bacterial adhesion are explored. Water contact angles, nanoindentation, and atomic

  2. Staphylococcus aureus-fibronectin interactions with and without fibronectin-binding proteins and their role in adhesion and desorption

    NARCIS (Netherlands)

    Xu, Chun; Boks, Niels P; de Vries, Jacob; Kaper, Harm; Norde, Willem; Busscher, Hendrik; van der Mei, Henderina

    2008-01-01

    Adhesion and residence-time-dependent desorption of two Staphylococcus aureus strains with and without fibronectin (Fn) binding proteins (FnBPs) on Fn-coated glass were compared under flow conditions. To obtain a better understanding of the role of Fn-FnBP binding, the adsorption enthalpies of Fn wi

  3. Staphylococcus aureus-Fibronectin Interactions with and without Fibronectin-Binding Proteins and Their Role in Adhesion and Desorption

    NARCIS (Netherlands)

    Xu, C.P.; Boks, N.P.; Vries, de J.; Kaper, H.J.; Norde, W.; Busscher, H.J.; Mei, van der H.C.

    2008-01-01

    Adhesion and residence-time-dependent desorption of two Staphylococcus aureus strains with and without fibronectin (Fn) binding proteins (FnBPs) on Fn-coated glass were compared under flow conditions. To obtain a better understanding of the role of Fn-FnBP binding, the adsorption enthalpies of Fn wi

  4. B-cell receptor-associated protein 31 regulates human embryonic stem cell adhesion, stemness, and survival via control of epithelial cell adhesion molecule.

    Science.gov (United States)

    Kim, Won-Tae; Seo Choi, Hong; Min Lee, Hyun; Jang, Young-Joo; Ryu, Chun Jeih

    2014-10-01

    B-Cell receptor-associated protein 31 (BAP31) regulates the export of secreted membrane proteins from the endoplasmic reticulum (ER) to the downstream secretory pathway. Previously, we generated a monoclonal antibody 297-D4 against the surface molecule on undifferentiated human embryonic stem cells (hESCs). Here, we found that 297-D4 antigen was localized to pluripotent hESCs and downregulated during early differentiation of hESCs and identified that the antigen target of 297-D4 was BAP31 on the hESC-surface. To investigate the functional role of BAP31 in hESCs, BAP31 expression was knocked down by small interfering RNA. BAP31 depletion impaired hESC self-renewal and pluripotency and drove hESC differentiation into multicell lineages. BAP31 depletion hindered hESC proliferation by arresting cell cycle at G0/G1 phase and inducing caspase-independent cell death. Interestingly, BAP31 depletion reduced hESC adhesion to extracellular matrix (ECM). Analysis of cell surface molecules showed decreased expression of epithelial cell adhesion molecule (EpCAM) in BAP31-depleted hESCs, while ectopic expression of BAP31 elevated the expression of EpCAM. EpCAM depletion also reduced hESC adhesion to ECM, arrested cell cycle at G0/G1 phase and induced cell death, producing similar effects to those of BAP31 depletion. BAP31 and EpCAM were physically associated and colocalized at the ER and cell surface. Both BAP31 and EpCAM depletion decreased cyclin D1 and E expression and suppressed PI3K/Akt signaling, suggesting that BAP31 regulates hESC stemness and survival via control of EpCAM expression. These findings provide, for the first time, mechanistic insights into how BAP31 regulates hESC stemness and survival via control of EpCAM expression.

  5. Pathogenic Naegleria fowleri and non-pathogenic Naegleria lovaniensis exhibit differential adhesion to, and invasion of, extracellular matrix proteins.

    Science.gov (United States)

    Jamerson, Melissa; da Rocha-Azevedo, Bruno; Cabral, Guy A; Marciano-Cabral, Francine

    2012-03-01

    Naegleria fowleri and Naegleria lovaniensis are closely related free-living amoebae found in the environment. N. fowleri causes primary amoebic meningoencephalitis (PAM), a rapidly fatal disease of the central nervous system, while N. lovaniensis is non-pathogenic. N. fowleri infection occurs when the amoebae access the nasal passages, attach to the nasal mucosa and its epithelial lining, and migrate to the brain. This process involves interaction with components of the host extracellular matrix (ECM). Since the ability to invade tissues can be a characteristic that distinguishes pathogenic from non-pathogenic amoebae, the objective of this study was to assess adhesion to, and invasion of, the ECM by these two related but distinct Naegleria species. N. fowleri exhibited a higher level of adhesion to the ECM components laminin-1, fibronectin and collagen I. Scanning electron microscopy revealed that N. fowleri attached on ECM substrata exhibited a spread-out appearance that included the presence of focal adhesion-like structures. Western immunoblotting revealed two integrin-like proteins for both species, but one of these, with a molecular mass of approximately 70 kDa, was detected at a higher level in N. fowleri. Confocal microscopy indicated that the integrin-like proteins co-localized to the focal adhesion-like structures. Furthermore, anti-integrin antibody decreased adhesion of N. fowleri to ECM components. Finally, N. fowleri disrupted 3D ECM scaffolds, while N. lovaniensis had a minimal effect. Collectively, these results indicate a distinction in adhesion to, and invasion of, ECM proteins between N. fowleri and N. lovaniensis.

  6. Control of high affinity interactions in the talin C terminus: how talin domains coordinate protein dynamics in cell adhesions.

    OpenAIRE

    2009-01-01

    In cell-extracellular matrix junctions (focal adhesions), the cytoskeletal protein talin is central to the connection of integrins to the actin cytoskeleton. Talin is thought to mediate this connection via its two integrin, (at least) three actin, and several vinculin binding sites. The binding sites are cryptic in the head-to-rod autoinhibited cytoplasmic form of the protein and require (stepwise) conformational activation. This activation process, however, remains poorly understood, and the...

  7. Scaffold-forming and Adhesive Contributions of Synthetic Laminin-binding Proteins to Basement Membrane Assembly.

    Science.gov (United States)

    McKee, Karen K; Capizzi, Stephanie; Yurchenco, Peter D

    2009-03-27

    Laminins that possess three short arms contribute to basement membrane assembly by anchoring to cell surfaces, polymerizing, and binding to nidogen and collagen IV. Although laminins containing the alpha4 and alpha5 subunits are expressed in alpha2-deficient congenital muscular dystrophy, they may be ineffective substitutes because they bind weakly to cell surfaces and/or because they lack the third arm needed for polymerization. We asked whether linker proteins engineered to bind to deficient laminins that provide such missing activities would promote basement membrane assembly in a Schwann cell model. A chimeric fusion protein (alphaLNNd) that adds a short arm terminus to laminin through the nidogen binding locus was generated and compared with the dystrophy-ameliorating protein miniagrin (mAgrin) that binds to the laminin coiled-coil dystroglycan and sulfatides. alphaLNNd was found to mediate laminin binding to collagen IV, to bind to galactosyl sulfatide, and to selectively convert alpha-short arm deletion-mutant laminins LmDeltaalphaLN and LmDeltaalphaLN-L4b into polymerizing laminins. This protein enabled polymerization-deficient laminin but not an adhesion-deficient laminin lacking LG domains (LmDeltaLG) to assemble an extracellular matrix on Schwann cell surfaces. mAgrin, on the other hand, enabled LmDeltaLG to form an extracellular matrix on cell surfaces without increasing accumulation of non-polymerizing laminins. These gain-of-function studies reveal distinct polymerization and anchorage contributions to basement membrane assembly in which the three different LN domains mediate the former, and the LG domains provide primary anchorage with secondary contributions from the alphaLN domain. These findings may be relevant for an understanding of the pathogenesis and treatment of laminin deficiency states.

  8. Design Methods of Cell Adhesion Proteins Based on ELISA Usable in-vitro in Gene Therapy

    Directory of Open Access Journals (Sweden)

    E Hosseini

    2016-07-01

    Full Text Available Background & aim: One of the strategies to improve the therapeutic gene is targeting gene therapy. A method which can be considered, is adding code sequences peptide or protein with high tendency to target cells and secreting the therapeutic gene encodes a protein. However, evaluating the effectiveness of such changes in the targeted cell binding protein gene product with the usual therapeutic methods produced in prokaryotic system is directly impossible. The purpose of this study was to evaluate the design methods of cell adhesion proteins based on ELISA usable in-vitro in gene therapy. Methods: In order to target the therapeutic gene Mda-7 by using genetic engineering, peptide coding sequence RGD4C with the tendency to cancerous cell surface integrin were inserted shortly after the artificial signal peptide sequence and the N-terminal coding region of the protein. Then, the modified and unmodified cDNA eukaryotic expression vector pCDNA3.1 were matched. Vectors were transfected in HEK-293 cell line. Then Mda-7 secreted expression levels were measured in cell culture by ELISA. After adjusting the protein concentration of Mda-7 and RGD.Mda-7, in cells transfected media, they were used as a source of protein. Reduce the concentration of these genes was assessed two hours after exposure to the integrin cell lines with HepG2, M21 and lacking integrin Saos-2  were also determined by ELISA. The present study was conducted three times independently.  Data were analyzed using t-test. Results: Statistical analysis of the results suggested that the gene product of the gene product RGD.Mda-7 and Mda-7 to connect to HepG2 cells and M21 were more likely to have integrin. While binding to the cell lines of Saos-2, no significant difference were observed. Conclusions: It seems the present ELISA based method was a suitable strategy for cell attachment assay in gene therapy research.  

  9. Orphan G protein-coupled receptor GPRC5A modulates integrin β1-mediated epithelial cell adhesion.

    Science.gov (United States)

    Bulanova, Daria R; Akimov, Yevhen A; Rokka, Anne; Laajala, Teemu D; Aittokallio, Tero; Kouvonen, Petri; Pellinen, Teijo; Kuznetsov, Sergey G

    2016-10-07

    G-Protein Coupled Receptor (GPCR), Class C, Group 5, Member A (GPRC5A) has been implicated in several malignancies. The underlying mechanisms, however, remain poorly understood. Using a panel of human cell lines, we demonstrate that CRISPR/Cas9-mediated knockout and RNAi-mediated depletion of GPRC5A impairs cell adhesion to integrin substrates: collagens I and IV, fibronectin, as well as to extracellular matrix proteins derived from the Engelbreth-Holm-Swarm (EHS) mouse sarcoma (Matrigel). Consistent with the phenotype, knock-out of GPRC5A correlated with a reduced integrin β1 (ITGB1) protein expression, impaired phosphorylation of the focal adhesion kinase (FAK), and lower activity of small GTPases RhoA and Rac1. Furthermore, we provide the first evidence for a direct interaction between GPRC5A and a receptor tyrosine kinase EphA2, an upstream regulator of FAK, although its contribution to the observed adhesion phenotype is unclear. Our findings reveal an unprecedented role for GPRC5A in regulation of the ITGB1-mediated cell adhesion and it's downstream signaling, thus indicating a potential novel role for GPRC5A in human epithelial cancers.

  10. Human heat shock protein (Hsp) 90 interferes with Neisseria meningitidis adhesin A (NadA)-mediated adhesion and invasion.

    Science.gov (United States)

    Montanari, Paolo; Bozza, Giuseppe; Capecchi, Barbara; Caproni, Elena; Barrile, Riccardo; Norais, Nathalie; Capitani, Mirco; Sallese, Michele; Cecchini, Paola; Ciucchi, Laura; Gao, Zhenai; Rappuoli, Rino; Pizza, Mariagrazia; Aricò, Beatrice; Merola, Marcello

    2012-03-01

    NadA (N eisseria meningitidisadhesin A), a meningococcal surface protein, mediates adhesion to and invasion of human cells, an activity in which host membrane proteins have been implicated. While investigating these host factors in human epithelial cells by affinity chromatography, we discovered an unanticipated interaction of NadA with heat shock protein (Hsp) 90, a molecular chaperone. The specific in vitro interaction of recombinant soluble NadA and Hsp90 was confirmed by co-immunoprecipitations, dot and far-Western blot. Intriguingly, ADP, but not ATP, was required for this association, and the Hsp90 inhibitor 17-AAG promoted complex formation. Hsp90 binding to an Escherichia coli strain used as carrier to express surface exposed NadA confirmed these results in live bacteria. We also examined RNA interference, plasmid-driven overexpression, addition of exogenous rHsp90 and 17-AAG inhibition in human epithelial cells to further elucidate the involvement of Hsp90 in NadA-mediated adhesion and invasion. Together, these data suggest an inverse correlation between the amount of host Hsp90 and the NadA adhesive/invasive phenotype. Confocal microscopy also demonstrated that meningococci interact with cellular Hsp90, a completely novel finding. Altogether our results show that variation of host Hsp90 expression or activity interferes with adhesive and invasive events driven by NadA.

  11. Protein Aggregation Formed by Recombinant cp19k Homologue of Balanus albicostatus Combined with an 18 kDa N-Terminus Encoded by pET-32a(+ Plasmid Having Adhesion Strength Comparable to Several Commercial Glues.

    Directory of Open Access Journals (Sweden)

    Chao Liang

    Full Text Available The barnacle is well known for its tenacious and permanent attachment to a wide variety of underwater substrates, which is accomplished by synthesizing, secreting and curing a mixture of adhesive proteins termed "barnacle cement". In order to evaluate interfacial adhesion abilities of barnacle cement proteins, the cp19k homologous gene in Balanus albicostatus (Balcp19k was cloned and expressed in Escherichia coli. Here, we report an intriguing discovery of a gel-like super adhesive aggregation produced by Trx-Balcp19k, a recombinant Balcp19k fusion protein. The Trx-Balcp19k consists of an 18 kDa fragment at the N-terminus, which is encoded by pET-32a(+ plasmid and mainly comprised of a thioredoxin (Trx tag, and Balcp19k at the C-terminus. The sticky aggregation was designated as "Trx-Balcp19k gel", and the bulk adhesion strength, biochemical composition, as well as formation conditions were all carefully investigated. The Trx-Balcp19k gel exhibited strong adhesion strength of 2.10 ± 0.67 MPa, which was approximately fifty folds higher than that of the disaggregated Trx-Balcp19k (40 ± 8 kPa and rivaled those of commercial polyvinyl acetate (PVA craft glue (Mont Marte, Australia and UHU glue (UHU GmbH & Co. KG, Germany. Lipids were absent from the Trx-Balcp19k gel and only a trace amount of carbohydrates was detected. We postulate that the electrostatic interactions play a key role in the formation of Trx-Balcp19k gel, by mediating self-aggregation of Trx-Balcp19k based on its asymmetric distribution pattern of charged amino acids. Taken together, we believe that our discovery not only presents a promising biological adhesive with potential applications in both biomedical and technical fields, but also provides valuable paradigms for molecular design of bio-inspired peptide- or protein-based materials.

  12. Composites containing albumin protein or cyanoacrylate adhesives and biodegradable scaffolds: II. In vivo wound closure study in a rat model

    Science.gov (United States)

    McNally-Heintzelman, Karen M.; Heintzelman, Douglas L.; Duffy, Mark T.; Bloom, Jeffrey N.; Soller, Eric C.; Gilmour, Travis M.; Hoffman, Grant T.; Edward, Deepak

    2004-07-01

    Our Scaffold-Enhanced Biological Adhesive (SEBA) system was investigated as an alternative to sutures or adhesives alone for repair of wounds. Two scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biologic material, small intestinal submucosa, manufactured by Cook BioTech. Two adhesive materials were also investigated: (i) a biologic adhesive composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser; and (ii) Ethicon"s Dermabond, a 2-octyl-cyanoacrylate. The tensile strength and time-to-failure of skin incisions repaired in vivo in a rat model were measured at seven days postoperative. Incisions closed by protein solder alone, by Dermabond alone, or by suture, were also tested for comparison. The tensile strength of repairs formed using the SEBA system were 50% to 65% stronger than repairs formed by suture or either adhesive alone, with significantly less variations within each experimental group (average standard deviations of 15% for SEBA versus 38% for suture and 28% for adhesive alone). In addition, the time-to-failure curves showed a longevity not previously seen with the suture or adhesive alone techniques. The SEBA system acts to keep the dermis in tight apposition during the critical early phase of wound healing when tissue gaps are bridged by scar and granulation tissue. It has the property of being more flexible than either of the adhesives alone and may allow the apposed edges to move in conjunction with each other as a unit for a longer period of time and over a greater range of stresses than adhesives alone. This permits more rapid healing and establishment of integrity since the microgaps between the dermis edges are significantly reduced. By the time the scaffolds are sloughed from the wound site, there is greater strength and healing than that produced by adhesive alone or

  13. Photorhabdus adhesion modification protein (Pam) binds extracellular polysaccharide and alters bacterial attachment

    LENUS (Irish Health Repository)

    Jones, Robert T

    2010-05-12

    Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C) and human (37°C) temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS)-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR) binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect through mediation of

  14. Photorhabdus adhesion modification protein (Pam binds extracellular polysaccharide and alters bacterial attachment

    Directory of Open Access Journals (Sweden)

    Joyce Susan A

    2010-05-01

    Full Text Available Abstract Background Photorhabdus are Gram-negative nematode-symbiotic and insect-pathogenic bacteria. The species Photorhabdus asymbiotica is able to infect humans as well as insects. We investigated the secreted proteome of a clinical isolate of P. asymbiotica at different temperatures in order to identify proteins relevant to the infection of the two different hosts. Results A comparison of the proteins secreted by a clinical isolate of P. asymbiotica at simulated insect (28°C and human (37°C temperatures led to the identification of a small and highly abundant protein, designated Pam, that is only secreted at the lower temperature. The pam gene is present in all Photorhabdus strains tested and shows a high level of conservation across the whole genus, suggesting it is both ancestral to the genus and probably important to the biology of the bacterium. The Pam protein shows limited sequence similarity to the 13.6 kDa component of a binary toxin of Bacillus thuringiensis. Nevertheless, injection or feeding of heterologously produced Pam showed no insecticidal activity to either Galleria mellonella or Manduca sexta larvae. In bacterial colonies, Pam is associated with an extracellular polysaccharide (EPS-like matrix, and modifies the ability of wild-type cells to attach to an artificial surface. Interestingly, Surface Plasmon Resonance (SPR binding studies revealed that the Pam protein itself has adhesive properties. Although Pam is produced throughout insect infection, genetic knockout does not affect either insect virulence or the ability of P. luminescens to form a symbiotic association with its host nematode, Heterorhabditis bacteriophora. Conclusions We studied a highly abundant protein, Pam, which is secreted in a temperature-dependent manner in P. asymbiotica. Our findings indicate that Pam plays an important role in enhancing surface attachment in insect blood. Its association with exopolysaccharide suggests it may exert its effect

  15. Silk protein as a new optically transparent adhesion layer for an ultra-smooth sub-10 nm gold layer

    Science.gov (United States)

    Min, Kyungtaek; Umar, Muhammad; Ryu, Shinyoung; Lee, Soonil; Kim, Sunghwan

    2017-03-01

    Ultra-thin and ultra-smooth gold (Au) films are appealing for photonic applications including surface plasmon resonances and transparent contacts. However, poor adhesion at the Au–dielectric interface prohibits the formation of a mechanically stable, ultra-thin, and ultra-smooth Au film. A conventional solution is to use a metallic adhesion layer, such as titanium and chromium, however such layers cause the optical properties of pure Au to deteriorate. Here we report the use of silk protein to enhance the adhesion at the Au–dielectric interface, thus obtaining ultra-smooth sub-10 nm Au films. The Au films that were deposited onto the silk layer exhibited superior surface roughness to those deposited on SiO2, Si, and poly(methyl methacrylate), along with improved adhesion, electrical conductivity, and optical transparency. Additionally, we confirm that a metal–insulator–metal optical resonator can be successfully generated using a silk insulating layer without the use of a metallic adhesion layer.

  16. Protein adsorption mechanisms determine the efficiency of thermally controlled cell adhesion on poly(N-isopropyl acrylamide) brushes.

    Science.gov (United States)

    Choi, Sangwook; Choi, Byung-Chan; Xue, Changying; Leckband, Deborah

    2013-01-14

    This study investigated the impact of the protein adsorption mechanism(s) on the efficiency of thermally controlled cell adhesion and release from poly(N-isopropyl acrylamide) brushes. Large format polymer gradients were used to screen for grafting densities and substrate chemistries that alter both cell adhesion at 37 °C and rapid cell release at 25 °C. In particular, the grafting conditions investigated allowed protein adsorption to the underlying substrate, penetration of the brush only, or adsorption to the outer edge of the film. At an average molecular weight of 30 kDa (degree of polymerization N ∼ 270), the results show that robust protein adsorption to polymer brushes impairs rapid cell release below the lower critical solution temperature. Conversely, grafting conditions that permit protein penetration of the brush but block strong adsorption to the underlying substrate support cell adhesion above the transition temperature and ensure efficient cell recovery at lower temperature. These findings demonstrate the impact of protein adsorption mechanisms, surface chemistry, and polymer properties on thermally controlled cell capture and release.

  17. IL-2 induces beta2-integrin adhesion via a wortmannin/LY294002-sensitive, rapamycin-resistant pathway. Phosphorylation of a 125-kilodalton protein correlates with induction of adhesion, but not mitogenesis

    DEFF Research Database (Denmark)

    Nielsen, M; Svejgaard, A; Skov, S;

    1996-01-01

    beta2-integrin-dependent, homotypic adhesion in Ag-specific, human T cell lines. The IL-2 adhesion response is blocked by wortmannin and LY294002, inhibitors of phosphatidylinositol-3 (PI-3) kinase activity. In contrast, rapamycin strongly inhibits IL-2-induced proliferation without inhibiting IL-2......, and cytochalasin E almost completely inhibit cytokine-induced tyrosine phosphorylation of p125, whereas tyrosine phosphorylation of PI-3 kinase, Janus kinases, Stat3, Stat5, and other proteins is unaffected. In contrast, rapamycin has little effect on IL-2-induced phosphorylation of p125. Taken together......, these data suggest that 1) IL-2R ligation induces homotypic adhesion through a wortmannin/LY294002-sensitive, rapamycin-resistant pathway, 2) tyrosine kinases play a critical role in cytokine-induced adhesion, and 3) adhesion, but not mitogenesis, correlates with enhanced tyrosine phosphorylation...

  18. Mammalian adenylyl cyclase-associated protein 1 (CAP1) regulates cofilin function, the actin cytoskeleton, and cell adhesion.

    Science.gov (United States)

    Zhang, Haitao; Ghai, Pooja; Wu, Huhehasi; Wang, Changhui; Field, Jeffrey; Zhou, Guo-Lei

    2013-07-19

    CAP (adenylyl cyclase-associated protein) was first identified in yeast as a protein that regulates both the actin cytoskeleton and the Ras/cAMP pathway. Although the role in Ras signaling does not extend beyond yeast, evidence supports that CAP regulates the actin cytoskeleton in all eukaryotes including mammals. In vitro actin polymerization assays show that both mammalian and yeast CAP homologues facilitate cofilin-driven actin filament turnover. We generated HeLa cells with stable CAP1 knockdown using RNA interference. Depletion of CAP1 led to larger cell size and remarkably developed lamellipodia as well as accumulation of filamentous actin (F-actin). Moreover, we found that CAP1 depletion also led to changes in cofilin phosphorylation and localization as well as activation of focal adhesion kinase (FAK) and enhanced cell spreading. CAP1 forms complexes with the adhesion molecules FAK and Talin, which likely underlie the cell adhesion phenotypes through inside-out activation of integrin signaling. CAP1-depleted HeLa cells also had substantially elevated cell motility as well as invasion through Matrigel. In summary, in addition to generating in vitro and in vivo evidence further establishing the role of mammalian CAP1 in actin dynamics, we identified a novel cellular function for CAP1 in regulating cell adhesion.

  19. Cross talk between tetanus neurotoxin-insensitive vesicle-associated membrane protein-mediated transport and L1-mediated adhesion.

    Science.gov (United States)

    Alberts, Philipp; Rudge, Rachel; Hinners, Ina; Muzerelle, Aude; Martinez-Arca, Sonia; Irinopoulou, Theano; Marthiens, Veronique; Tooze, Sharon; Rathjen, Fritz; Gaspar, Patricia; Galli, Thierry

    2003-10-01

    The membrane-trafficking pathway mediated by tetanus neurotoxin-insensitive vesicle-associated membrane protein (TI-VAMP) in neurons is still unknown. We show herein that TI-VAMP expression is necessary for neurite outgrowth in PC12 cells and hippocampal neurons in culture. TI-VAMP interacts with plasma membrane and endosomal target soluble N-ethylmaleimide-sensitive factor attachment protein receptors, suggesting that TI-VAMP mediates a recycling pathway. L1, a cell-cell adhesion molecule involved in axonal outgrowth, colocalized with TI-VAMP in the developing brain, neurons in culture, and PC12 cells. Plasma membrane L1 was internalized into the TI-VAMP-containing compartment. Silencing of TI-VAMP resulted in reduced expression of L1 at the plasma membrane. Finally, using the extracellular domain of L1 and N-cadherin immobilized on beads, we found that the silencing of TI-VAMP led to impaired L1- but not N-cadherin-mediated adhesion. Furthermore, TI-VAMP- but not synaptobrevin 2-containing vesicles accumulated at the site of the L1 bead-cell junction. We conclude that TI-VAMP mediates the intracellular transport of L1 and that L1-mediated adhesion controls this membrane trafficking, thereby suggesting an important cross talk between membrane trafficking and cell-cell adhesion.

  20. Modulation of endogenous Cysteine Protease Inhibitor (ICP) 1 expression in Entamoeba histolytica affects amoebic adhesion to Extracellular Matrix proteins.

    Science.gov (United States)

    Lee, Young Ah; Saito-Nakano, Yumiko; Kim, Kyeong Ah; Min, Arim; Nozaki, Tomoyoshi; Shin, Myeong Heon

    2015-02-01

    Entamoeba histolytica is an enteric tissue-invading protozoan parasite that causes amoebic colitis and occasionally liver abscess in humans. During tissue invasion, amoebic adhesion to host components is an important event for host cell death leading to successful invasion and infection. Among amoebic virulence factors, Gal/GalNAc lectin is known to be major adhesion factor to host cells. In this study, we investigated the role of amoebic secreted CP (Cysteine Proteases) in amoebic adhesion to extracellular matrix (ECM) protein using CP inhibitor and E. histolytica strains in which the endogenous inhibitor of cysteine protease (ICP) 1 gene was overexpressed (ICP1(+)) or repressed by antisense small RNA-mediated gene silencing (ICP1(-)). We found that pretreatment of wild-type amoebae with CP inhibitor E64, or thiol-group modifiers such as diamide and N-Ethylmaleimide resulted in a significant decrease in adhesion to laminin and collagen ECM proteins. Furthermore, ICP1(+) strain, with a reduction of secreted CP activity, exhibited reduced ability by 40% to adhere to laminin. In contrast, ICP1(-) strain, with a 1.9-fold increase of secreted CP activity, showed a two-fold increase in amoebic adherence to laminin compared to the control strain. In addition, total amount of secreted CP5 was decreased in ICP1(+) amoeba. Conversely, total amount of secreted CP1 and mature-form CP5 were increased in ICP1(-) amoeba. We also found that ICP1 was secreted into extracellular milieu. These results suggest that secreted CP activity by E. histolytica may be an important factor affecting adhesion to host proteins, and regulation of CP secretion by ICP plays a major role in pathogenesis. This study provides insight into the CP-mediated tissue pathogenesis in amoeba-invaded lesions during human amoebiasis.

  1. C1q/TNF-related protein-9 inhibits cytokine-induced vascular inflammation and leukocyte adhesiveness via AMP-activated protein kinase activation in endothelial cells.

    Science.gov (United States)

    Jung, Chang Hee; Lee, Min Jung; Kang, Yu Mi; Lee, Yoo La; Seol, So Mi; Yoon, Hae Kyeong; Kang, Sang-Wook; Lee, Woo Je; Park, Joong-Yeol

    2016-01-05

    Although recent studies have reported cardioprotective effects of C1q/TNF-related protein 9 (CTRP9), the closet adiponectin paralog, its role on cytokine-induced endothelial inflammation is unknown. We investigated whether CTRP9 prevented inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation and inhibited the expression of adhesion molecules and a chemokine in the vascular endothelial cell. We used human aortic endothelial cells (HAECs) to examine the effects of CTRP9 on NF-κB activation and the expression of NF-κB-mediated genes, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1). Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine. In an adhesion assay using THP-1 cells, CTRP9 reduced TNFα-induced adhesion of monocytes to HAECs. Treatment with CTRP9 significantly decreased TNFα-induced activation of NF-κB, as well as the expression of ICAM-1, VCAM-1, and MCP-1. In addition, treatment with CTRP9 significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), the downstream target of AMPK. The inhibitory effect of CTRP9 on the expression of ICAM-1, VCAM-1, and MCP-1 and monocyte adhesion to HAECs was abolished after transfection with an AMPKα1-specific siRNA. Our study is the first to demonstrate that CTRP9 attenuates cytokine-induced vascular inflammation in endothelial cells mediated by AMPK activation.

  2. Mussel adhesive protein coating: A potential therapeutic method for self-healing of cracked teeth

    Directory of Open Access Journals (Sweden)

    Li Bo-Lin

    2015-01-01

    Full Text Available Introduction: Nowadays, cracked tooth syndrome is the third main cause of tooth extraction, following caries and periodontal diseases, done in almost all the dental clinics. Nevertheless, the diagnosis and treatment of this condition remain controversial. All candidate therapeutics, such as occlusal adjustment, preventive filling, root canal therapy (RCT, and crown restoration, provide unpredictable outcomes. As such, methods to prevent further crack development and to induce crack self-healing must be developed. The Hypothesis: Mussels secreting adhesive foot protein (Mafp can attach to various surfaces under aqueous conditions. In nature, mussels adhere to stones and deposit layer by layer through mineralization, thereby forming mussel-stone composites with excellent mechanical property. Given the natural process of mussel-stone complex formation, we hypothesize that application of Mafp coating at the crack interface may mineralize the cracks by capturing calcium and phosphate ions from the saliva. This process consequently leads to crack self-healing and complete restoration of the tooth structure. Evaluation of the Hypothesis: To test our hypothesis, we need to develop a model in vivo. Cracked teeth disks are adhered together using Mafp solution. Then, the tooth disks are sutured on the interior side of the cheeks. After regular intervals, the disks are removed and characterized. Scanning electron microscopy is performed to evaluate the morphology of the crack interface. Microhardness and shear bond strength are used to evaluate the mechanical property of the healing cracked zone. Transmission electron microscopy is also conducted to evaluate the crystallinity of the crack interface.

  3. Plasmodium vivax thrombospondin related adhesion protein: immunogenicity and protective efficacy in rodents and Aotus monkeys

    Directory of Open Access Journals (Sweden)

    Angélica Castellanos

    2007-06-01

    Full Text Available The thrombospondin related adhesion protein (TRAP is a malaria pre-erythrocytic antigen currently pursued as malaria vaccine candidate to Plasmodium falciparum. In this study, a long synthetic peptide (LSP representing a P. vivax TRAP fragment involved in hepatocyte invasion was formulated in both Freund and Montanide ISA 720 adjutants and administered by IM and subcutaneous routes to BALB/c mice and Aotus monkeys. We measured specific humoral immune responses in both animal species and performed a sporozoite challenge in Aotus monkeys to assess the protective efficacy of the vaccine. After immunization both mice and Aotus seroconverted as shown by ELISA, and the specific anti-peptide antibodies cross reacted with the parasite in IFAT assays. Only two out of six immunized animals became infected after P. vivax sporozoite challenge as compared with four out of six animals from the control group. These results suggest that this TRAP fragment has protective potential against P. vivax malaria and deserves further studies as vaccine candidate.

  4. Adhesive properties of Clostridium perfringens to extracellular matrix proteins collagens and fibronectin.

    Science.gov (United States)

    Hitsumoto, Yasuo; Morita, Naomi; Yamazoe, Ryosuke; Tagomori, Mika; Yamasaki, Tsutomu; Katayama, Seiichi

    2014-02-01

    The adhesive properties of Clostridium perfringens to collagens, gelatin, fibronectin (Fn), Fn-prebound collagens, and Fn-prebound gelatin were investigated. C. perfringens could bind to Fn-prebound collagen type II, type III, and gelatin, but not to gelatin or collagens except for collagen type I directly. Recombinant Fn-binding proteins of C. perfringens, rFbpA and rFbpB, were used to examine Fn-mediated bacterial adherence to collagen type I. In the presence of rFbps, C. perfringens adherence to Fn-prebound collagen type I was inhibited in a dose-dependent manner. Fn was not released from the coated collagen type I by the presence of rFbps, and rFbps did not bind to collagen type I. Thus, the inhibition of C. perfringens binding to Fn-prebound collagen type I by rFbps could not be explained by the removal of Fn from collagen or by the competitive binding of rFbps to collagen. Instead, both rFbps were found to bind to C. perfringens. These results suggest the possibility that rFbps may bind to the putative Fn receptor expressed on C. perfringens and competitively inhibit Fn binding to C. perfringens.

  5. Conserved roles of the prion protein domains on subcellular localization and cell-cell adhesion.

    Directory of Open Access Journals (Sweden)

    Gonzalo P Solis

    Full Text Available Analyses of cultured cells and transgenic mice expressing prion protein (PrP deletion mutants have revealed that some properties of PrP -such as its ability to misfold, aggregate and trigger neurotoxicity- are controlled by discrete molecular determinants within its protein domains. Although the contributions of these determinants to PrP biosynthesis and turnover are relatively well characterized, it is still unclear how they modulate cellular functions of PrP. To address this question, we used two defined activities of PrP as functional readouts: 1 the recruitment of PrP to cell-cell contacts in Drosophila S2 and human MCF-7 epithelial cells, and 2 the induction of PrP embryonic loss- and gain-of-function phenotypes in zebrafish. Our results show that homologous mutations in mouse and zebrafish PrPs similarly affect their subcellular localization patterns as well as their in vitro and in vivo activities. Among PrP's essential features, the N-terminal leader peptide was sufficient to drive targeting of our constructs to cell contact sites, whereas lack of GPI-anchoring and N-glycosylation rendered them inactive by blocking their cell surface expression. Importantly, our data suggest that the ability of PrP to homophilically trans-interact and elicit intracellular signaling is primarily encoded in its globular domain, and modulated by its repetitive domain. Thus, while the latter induces the local accumulation of PrPs at discrete punctae along cell contacts, the former counteracts this effect by promoting the continuous distribution of PrP. In early zebrafish embryos, deletion of either domain significantly impaired PrP's ability to modulate E-cadherin cell adhesion. Altogether, these experiments relate structural features of PrP to its subcellular distribution and in vivo activity. Furthermore, they show that despite their large evolutionary history, the roles of PrP domains and posttranslational modifications are conserved between mouse and

  6. Adhesion protein VSIG1 is required for the proper differentiation of glandular gastric epithelia.

    Directory of Open Access Journals (Sweden)

    Odgerel Oidovsambuu

    Full Text Available VSIG1, a cell adhesion protein of the immunoglobulin superfamily, is preferentially expressed in stomach, testis, and certain gastric, esophageal and ovarian cancers. Here, we describe the expression patterns of three alternatively spliced isoforms of mouse Vsig1 during pre- and postnatal development of stomach and potential function of Vsig1 in differentiation of gastric epithelia. We show that isoforms Vsig1A and Vsig1B, which differ in the 3'untranslated region, are expressed in the early stages of stomach development. Immunohistochemical analysis revealed that VSIG1 is restricted to the adherens junction of the glandular epithelium. The shorter transcript Vsig1C is restricted to the testis, encodes an N-terminal truncated protein and is presumably regulated by an internal promoter, which is located upstream of exon 1b. To determine whether the 5' flanking region of exon 1a specifically targets the expression of Vsig1 to stomach epithelia, we generated and analyzed transgenic mice. The 4.8-kb fragment located upstream of exon 1a was sufficient to direct the expression of the reporter gene to the glandular epithelia of transgenic stomach. To determine the role of VSIG1 during the development of stomach epithelia, an X-linked Vsig1 was inactivated in embryonic stem cells (ESCs. Although Vsig1(-/Y ESCs were only able to generate low coat color chimeric mice, no male chimeras transmitted the targeted allele to their progeny suggesting that the high contribution of Vsig1(-/Y cells leads to the lethality of chimeric embryos. Analysis of chimeric stomachs revealed the differentiation of VSIG1-null cells into squamous epithelia inside the glandular region. These results suggest that VSIG1 is required for the establishment of glandular versus squamous epithelia in the stomach.

  7. Adhesion protein VSIG1 is required for the proper differentiation of glandular gastric epithelia.

    Science.gov (United States)

    Oidovsambuu, Odgerel; Nyamsuren, Gunsmaa; Liu, Shuai; Göring, Wolfgang; Engel, Wolfgang; Adham, Ibrahim M

    2011-01-01

    VSIG1, a cell adhesion protein of the immunoglobulin superfamily, is preferentially expressed in stomach, testis, and certain gastric, esophageal and ovarian cancers. Here, we describe the expression patterns of three alternatively spliced isoforms of mouse Vsig1 during pre- and postnatal development of stomach and potential function of Vsig1 in differentiation of gastric epithelia. We show that isoforms Vsig1A and Vsig1B, which differ in the 3'untranslated region, are expressed in the early stages of stomach development. Immunohistochemical analysis revealed that VSIG1 is restricted to the adherens junction of the glandular epithelium. The shorter transcript Vsig1C is restricted to the testis, encodes an N-terminal truncated protein and is presumably regulated by an internal promoter, which is located upstream of exon 1b. To determine whether the 5' flanking region of exon 1a specifically targets the expression of Vsig1 to stomach epithelia, we generated and analyzed transgenic mice. The 4.8-kb fragment located upstream of exon 1a was sufficient to direct the expression of the reporter gene to the glandular epithelia of transgenic stomach. To determine the role of VSIG1 during the development of stomach epithelia, an X-linked Vsig1 was inactivated in embryonic stem cells (ESCs). Although Vsig1(-/Y) ESCs were only able to generate low coat color chimeric mice, no male chimeras transmitted the targeted allele to their progeny suggesting that the high contribution of Vsig1(-/Y) cells leads to the lethality of chimeric embryos. Analysis of chimeric stomachs revealed the differentiation of VSIG1-null cells into squamous epithelia inside the glandular region. These results suggest that VSIG1 is required for the establishment of glandular versus squamous epithelia in the stomach.

  8. Mussel-Inspired Surface Chemistry for Multifunctional Coatings

    Science.gov (United States)

    Lee, Haeshin; Dellatore, Shara M.; Miller, William M.; Messersmith, Phillip B.

    2007-10-01

    We report a method to form multifunctional polymer coatings through simple dip-coating of objects in an aqueous solution of dopamine. Inspired by the composition of adhesive proteins in mussels, we used dopamine self-polymerization to form thin, surface-adherent polydopamine films onto a wide range of inorganic and organic materials, including noble metals, oxides, polymers, semiconductors, and ceramics. Secondary reactions can be used to create a variety of ad-layers, including self-assembled monolayers through deposition of long-chain molecular building blocks, metal films by electroless metallization, and bioinert and bioactive surfaces via grafting of macromolecules.

  9. Mac-2 binding protein is a cell-adhesive protein of the extracellular matrix which self-assembles into ring-like structures and binds beta1 integrins, collagens and fibronectin

    DEFF Research Database (Denmark)

    Sasaki, T; Brakebusch, C; Engel, J

    1998-01-01

    in solid-phase assays to collagens IV, V and VI, fibronectin and nidogen, but not to fibrillar collagens I and III or other basement membrane proteins. The protein also mediated adhesion of cell lines at comparable strength with laminin. Adhesion to M2BP was inhibited by antibodies to integrin beta1...

  10. The effect of temperature on adhesion forces between surfaces and model foods containing whey protein and sugar

    OpenAIRE

    Goode, K. R.; Bowen, James; Akhtar, N.; Robbins, P. T.; Fryer, P. J.

    2013-01-01

    The formation of fouling deposit from foods and food components is a severe problem in food processing and leads to frequent cleaning. The design of surfaces that resist fouling may decrease the need for cleaning and thus increase efficiency. Atomic force microscopy has been used to measure adhesion forces between stainless steel (SS) and fluoro-coated glass (FCG) microparticles and the model food deposits (i) whey protein (WPC), (ii) sweetened condensed milk, and (iii) caramel. Measurements ...

  11. Effects of ovarian cancer G protein coupled receptor 1 on the proliferation, migration, and adhesion of human ovarian cancer cells

    Institute of Scientific and Technical Information of China (English)

    REN Juan; ZHANG Long

    2011-01-01

    Background OGR1 was found as a G-protein coupled receptor (GPCR) and proton sensor. Our previous studies have found that OGR1 has inhibitory effect on the metastasis of prostate cancer. In order to investigate the roles of OGR1 gene in the biological activities of ovarian cancer, we studied the OGR1 effects on ovarian cancer cells, HEY cells.Methods OGR1 gene was transfected into HEY cell, in which endogenous expression is low. OGR1-overxepressed cells and vector-transfected cells were compared in different assays. Western blotting was employed to confirm the high expression level of OGR1. Cell proliferation was determined by MTT assay and cell doubling time assay. Cell migration assay (transwell assay) and cell adhesion assay were performed to determine the migration and adhesion potential of cells. Student's t test was employed for statistical analysis.Results Proliferation of OGR1-overexpressed cells was significantly reduced (P <0.01); cell migration was significantly inhibited in the OGR1-transfected cells (P <0.01); cell adhesion to extracellular matrix including fibronectin, vitronectin,collagen Ⅰ/Ⅳ was significantly increased (P <0.01).Conclusions OGR1 expression in human ovarian cancer cells significantly inhibited the cell proliferation and migration,but significantly enhanced cell adhesion to the extracellular matrix. It indicated that OGR1 may be a tumor suppressor gene for ovarian cancer.

  12. Adhesion and degranulation promoting adapter protein (ADAP is a central hub for phosphotyrosine-mediated interactions in T cells.

    Directory of Open Access Journals (Sweden)

    Marc Sylvester

    Full Text Available TCR stimulation leads to an increase in cellular adhesion among other outcomes. The adhesion and degranulation promoting adapter protein (ADAP is known to be rapidly phosphorylated after T cell stimulation and relays the TCR signal to adhesion molecules of the integrin family. While three tyrosine phosphorylation sites have been characterized biochemically, the binding capabilities and associated functions of several other potential phosphotyrosine motifs remain unclear. Here, we utilize in vitro phosphorylation and mass spectrometry to map novel phosphotyrosine sites in the C-terminal part of human ADAP (486-783. Individual tyrosines were then mutated to phenylalanine and their relevance for cellular adhesion and migration was tested experimentally. Functionally important tyrosine residues include two sites within the folded hSH3 domains of ADAP and two at the C-terminus. Furthermore, using a peptide pulldown approach in combination with stable isotope labeling in cell culture (SILAC we identified SLP-76, PLCgamma, PIK3R1, Nck, CRK, Gads, and RasGAP as phospho-dependent binding partners of a central YDDV motif of ADAP. The phosphorylation-dependent interaction between ADAP and Nck was confirmed by yeast two-hybrid analysis, immunoprecipitation and binary pulldown experiments, indicating that ADAP directly links integrins to modulators of the cytoskeleton independent of SLP-76.

  13. Protein kinase C, focal adhesions and the regulation of cell migration

    DEFF Research Database (Denmark)

    Fogh, Betina S; Multhaupt, Hinke A B; Couchman, John Robert

    2014-01-01

    Cell adhesion to extracellular matrix is a complex process involving protrusive activity driven by the actin cytoskeleton, engagement of specific receptors, followed by signaling and cytoskeletal organization. Thereafter, contractile and endocytic/recycling activities may facilitate migration...

  14. Recombinant S-layer proteins of Lactobacillus brevis mediating antibody adhesion to calf intestine alleviated neonatal diarrhea syndrome.

    Science.gov (United States)

    Khang, Yong-Ho; Park, Hee-Young; Jeong, Yoo-Seok; Kim, Jung-Ae; Kim, Young-Hwan

    2009-05-01

    A chimeric gene encoding enhanced green fluorescent protein (EGFP) and a S-layer protein from Lactobacillus brevis KCTC3102, and/or two copies of the Fc-binding Z-domain, a synthetic analog of the B-domain of protein A, was constructed and expressed in Escherichia coli BL21(DE3). The S-layer fusion proteins produced in a 500-l fermentor were likely to be stable in the range of pH 5 to 8 and 0 degree to 40 degrees . Their adhesive property enabled an easy and rapid immobilization of enzymes or antibodies on solid materials such as plastics, glass, sol-gel films, and intestinal epithelial cells. Owing to their affinity towards intestinal cells and immunoglobulin G, the Slayer fusion proteins enabled the adhesion of antibodies to human epithelial cells. In addition, feeding a mixture of the S-layer fusion proteins and antibodies against neonatal calf diarrhea (coronavirus, rotavirus, Escherichia coli, and Salmonella typhimurium) to Hanwoo calves resulted in 100% prevention of neonatal calf diarrhea syndrome (p<0.01),whereas feeding antibodies only resulted in 56% prevention.

  15. Members of the Pmp protein family of Chlamydia pneumoniae mediate adhesion to human cells via short repetitive peptide motifs.

    Science.gov (United States)

    Mölleken, Katja; Schmidt, Eleni; Hegemann, Johannes H

    2010-11-01

    Chlamydiae sp. are obligate intracellular pathogens that cause a variety of diseases in humans. Adhesion of the infectious elementary body to the eukaryotic host cell is a pivotal step in chlamydial pathogenesis. Here we describe the characterization of members of the polymorphic membrane protein family (Pmp), the largest protein family (with up to 21 members) unique to Chlamydiaceae. We show that yeast cells displaying Pmp6, Pmp20 or Pmp21 on their surfaces, or beads coated with the recombinant proteins, adhere to human epithelial cells. A hallmark of the Pmp protein family is the presence of multiple repeats of the tetrapeptide motifs FxxN and GGA(I, L, V) and deletion analysis shows that at least two copies of these motifs are needed for adhesion. Importantly, pre-treatment of human cells with recombinant Pmp6, Pmp20 or Pmp21 protein reduces infectivity upon subsequent challenge with Chlamydia pneumoniae and correlates with diminished attachment of Chlamydiae to target cells. Antibodies specific for Pmp21 can neutralize infection in vitro. Finally, a combination of two different Pmp proteins in infection blockage experiments shows additive effects, possibly suggesting similar functions. Our findings imply that Pmp6, Pmp20 and Pmp21 act as adhesins, are vital during infection and thus represent promising vaccine candidates.

  16. Analysis of the behaviours mediating barnacle cyprid reversible adhesion.

    Science.gov (United States)

    Aldred, Nick; Høeg, Jens T; Maruzzo, Diego; Clare, Anthony S

    2013-01-01

    When exploring immersed surfaces the cypris larvae of barnacles employ a tenacious and rapidly reversible adhesion mechanism to facilitate their characteristic 'walking' behaviour. Although of direct relevance to the fields of marine biofouling and bio-inspired adhesive development, the mechanism of temporary adhesion in cyprids remains poorly understood. Cyprids secrete deposits of a proteinaceous substance during surface attachment and these are often visible as 'footprints' on previously explored surfaces. The attachment structures, the antennular discs, of cyprids also present a complex morphology reminiscent of both the hairy appendages used by some terrestrial invertebrates for temporary adhesion and a classic 'suction cup'. Despite the numerous analytical approaches so-far employed, it has not been possible to resolve conclusively the respective contributions of viscoelastic adhesion via the proteinaceous 'temporary adhesive', 'dry' adhesion via the cuticular villi present on the disc and the behavioural contribution by the organism. In this study, high-speed photography was used for the first time to capture the behaviour of cyprids at the instant of temporary attachment and detachment. Attachment is facilitated by a constantly sticky disc surface - presumably due to the presence of the proteinaceous temporary adhesive. The tenacity of the resulting bond, however, is mediated behaviourally. For weak attachment the disc is constantly moved on the surface, whereas for a strong attachment the disc is spread out on the surface. Voluntary detachment is by force, requiring twisting or peeling of the bond - seemingly without any more subtle detachment behaviours. Micro-bubbles were observed at the adhesive interface as the cyprid detached, possibly an adaptation for energy dissipation. These observations will allow future work to focus more specifically on the cyprid temporary adhesive proteins, which appear to be fundamental to adhesion, inherently sticky and

  17. Analysis of the behaviours mediating barnacle cyprid reversible adhesion.

    Directory of Open Access Journals (Sweden)

    Nick Aldred

    Full Text Available When exploring immersed surfaces the cypris larvae of barnacles employ a tenacious and rapidly reversible adhesion mechanism to facilitate their characteristic 'walking' behaviour. Although of direct relevance to the fields of marine biofouling and bio-inspired adhesive development, the mechanism of temporary adhesion in cyprids remains poorly understood. Cyprids secrete deposits of a proteinaceous substance during surface attachment and these are often visible as 'footprints' on previously explored surfaces. The attachment structures, the antennular discs, of cyprids also present a complex morphology reminiscent of both the hairy appendages used by some terrestrial invertebrates for temporary adhesion and a classic 'suction cup'. Despite the numerous analytical approaches so-far employed, it has not been possible to resolve conclusively the respective contributions of viscoelastic adhesion via the proteinaceous 'temporary adhesive', 'dry' adhesion via the cuticular villi present on the disc and the behavioural contribution by the organism. In this study, high-speed photography was used for the first time to capture the behaviour of cyprids at the instant of temporary attachment and detachment. Attachment is facilitated by a constantly sticky disc surface - presumably due to the presence of the proteinaceous temporary adhesive. The tenacity of the resulting bond, however, is mediated behaviourally. For weak attachment the disc is constantly moved on the surface, whereas for a strong attachment the disc is spread out on the surface. Voluntary detachment is by force, requiring twisting or peeling of the bond - seemingly without any more subtle detachment behaviours. Micro-bubbles were observed at the adhesive interface as the cyprid detached, possibly an adaptation for energy dissipation. These observations will allow future work to focus more specifically on the cyprid temporary adhesive proteins, which appear to be fundamental to adhesion

  18. Activation of Adhesion G Protein-coupled Receptors: AGONIST SPECIFICITY OF STACHEL SEQUENCE-DERIVED PEPTIDES.

    Science.gov (United States)

    Demberg, Lilian M; Winkler, Jana; Wilde, Caroline; Simon, Kay-Uwe; Schön, Julia; Rothemund, Sven; Schöneberg, Torsten; Prömel, Simone; Liebscher, Ines

    2017-03-17

    Members of the adhesion G protein-coupled receptor (aGPCR) family carry an agonistic sequence within their large ectodomains. Peptides derived from this region, called the Stachel sequence, can activate the respective receptor. As the conserved core region of the Stachel sequence is highly similar between aGPCRs, the agonist specificity of Stachel sequence-derived peptides was tested between family members using cell culture-based second messenger assays. Stachel peptides derived from aGPCRs of subfamily VI (GPR110/ADGRF1, GPR116/ADGRF5) and subfamily VIII (GPR64/ADGRG2, GPR126/ADGRG6) are able to activate more than one member of the respective subfamily supporting their evolutionary relationship and defining them as pharmacological receptor subtypes. Extended functional analyses of the Stachel sequences and derived peptides revealed agonist promiscuity, not only within, but also between aGPCR subfamilies. For example, the Stachel-derived peptide of GPR110 (subfamily VI) can activate GPR64 and GPR126 (both subfamily VIII). Our results indicate that key residues in the Stachel sequence are very similar between aGPCRs allowing for agonist promiscuity of several Stachel-derived peptides. Therefore, aGPCRs appear to be pharmacologically more closely related than previously thought. Our findings have direct implications for many aGPCR studies, as potential functional overlap has to be considered for in vitro and in vivo studies. However, it also offers the possibility of a broader use of more potent peptides when the original Stachel sequence is less effective. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Dry adhesives with sensing features

    Science.gov (United States)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  20. Self-Adjustable Adhesion of Polyampholyte Hydrogels.

    Science.gov (United States)

    Roy, Chanchal Kumar; Guo, Hong Lei; Sun, Tao Lin; Ihsan, Abu Bin; Kurokawa, Takayuki; Takahata, Masakazu; Nonoyama, Takayuki; Nakajima, Tasuku; Gong, Jian Ping

    2015-12-02

    Developing nonspecific, fast, and strong adhesives that can glue hydrogels and biotissues substantially promotes the application of hydrogels as biomaterials. Inspired by the ubiquitous adhesiveness of bacteria, it is reported that neutral polyampholyte hydrogels, through their self-adjustable surface, can show rapid, strong, and reversible adhesion to charged hydrogels and biological tissues through the Coulombic interaction.

  1. Modulation of cell adhesion and migration by the histone methyltransferase subunit mDpy-30 and its interacting proteins.

    Directory of Open Access Journals (Sweden)

    Bin Xia

    Full Text Available We have previously shown that a subset of mDpy-30, an accessory subunit of the nuclear histone H3 lysine 4 methyltransferase (H3K4MT complex, also localizes at the trans-Golgi network (TGN, where its recruitment is mediated by the TGN-localized ARF guanine nucleotide exchange factor (ArfGEF BIG1. Depletion of mDpy-30 inhibits the endosome-to-TGN transport of internalized CIMPR receptors and concurrently promotes their accumulation at the cell protrusion. These observations suggest mDpy-30 may play a novel role at the crossroads of endosomal trafficking, nuclear transcription and adhesion/migration. Here we provide novel mechanistic and functional insight into this association. First, we demonstrate a direct interaction between mDpy-30 and BIG1 and locate the binding region in the N-terminus of BIG1. Second, we provide evidence that the depletion or overexpression of mDpy-30 enhances or inhibits cellular adhesion/migration of glioma cells in vitro, respectively. A similar increase in cell adhesion/migration is observed in cells with reduced levels of BIG1 or other H3K4MT subunits. Third, knockdown of mDpy-30, BIG1, or the RbBP5 H3K4MT subunit increases the targeting of beta1 integrin to cell protrusions, and suppression of H3K4MT activity by depleting mDpy-30 or RbBP5 leads to increased protein and mRNA levels of beta1 integrin. Moreover, stimulation of cell adhesion/migration via mDpy-30 knockdown is abolished after treating cells with a function-blocking antibody to beta1 integrin. Taken together, these data indicate that mDpy-30 and its interacting proteins function as a novel class of cellular adhesion/migration modulators partially by affecting the subcellular distribution of endosomal compartments as well as the expression of key adhesion/migration proteins such as beta1 integrin.

  2. Protein adhesion on silicon-supported hyperbranched poly(ethylene glycol) and poly(allylamine) thin films.

    Science.gov (United States)

    Dyer, Maureen A; Ainslie, Kristy M; Pishko, Michael V

    2007-06-19

    Hyperbranching poly(allylamine) (PAAm) and poly(ethylene glycol) (PEG) on silicon and its effect on protein adhesion was investigated. Hyperbranching involves sequential grafting of polymers on a surface with one of the components having multiple reactive sites. In this research, PAAm provided multiple amines for grafting PEG diacrylate. Current methodologies for generating PEG surfaces include PEG-silane monolayers or polymerized PEG networks. Hyperbranching combines the nanoscale thickness of monolayers with the surface coverage afforded by polymerization. A multistep approach was used to generate the silicon-supported hyperbranched polymers. The silicon wafer surface was initially modified with a vinyl silane followed by oxidation of the terminal vinyl group to present an acid function. Carbodiimide activation of the surface carboxyl group allowed for coupling to PAAm amines to form the first polymer layer. The polymers were hyperbranched by grafting alternating PEG and PAAm layers to the surface using Michael addition chemistry. The alternating polymers were grafted up to six total layers. The substrates remained hydrophilic after each modification. Static contact angles for PAAm (32-44 degrees) and PEG (33-37 degrees) were characteristic of the corresponding individual polymer (30-50 degrees for allylamine, 34-42 degrees for PEG). Roughness values varied from approximately 1 to 8 nm, but had no apparent affect on protein adhesion. Modifications terminating with a PEG layer reduced bovine serum albumin adhesion to the surface by approximately 80% as determined by ELISA and radiolabel binding studies. The hyperbranched PAAm and PEG surfaces described in this paper are nanometer-scale, multilayer films capable of reducing protein adhesion.

  3. Poly(ester urea)-Based Adhesives: Improved Deployment and Adhesion by Incorporation of Poly(propylene glycol) Segments.

    Science.gov (United States)

    Zhou, Jinjun; Bhagat, Vrushali; Becker, Matthew L

    2016-12-14

    The adhesive nature of mussels arises from the catechol moiety in the 3,4-dihydroxyphenylalanine (DOPA) amino acid, one of the many proteins that contribute to the unique adhesion properties of mussels. Inspired by these properties, many biomimetic adhesives have been developed over the past few years in an attempt to replace adhesives such as fibrin, cyanoacrylate, and epoxy glues. In the present work, we synthesized ethanol soluble but water insoluble catechol functionalized poly(ester urea) random copolymers that help facilitate delivery and adhesion in wet environments. Poly(propylene glycol) units incorporated into the polymer backbone impart ethanol solubility to these polymers, making them clinically relevant. A catechol to cross-linker ratio of 10:1 with a curing time of 4 h exceeded the performance of commercial fibrin glue (4.8 ± 1.4 kPa) with adhesion strength of 10.6 ± 2.1 kPa. These adhesion strengths are significant with the consideration that the adhesion studies were performed under wet conditions.

  4. Inspirational Journey

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Artists from across Europe and Asia ventured into the remote Chinese countryside to seek inspiration from the Miao Ethnic group "I’ve never been to Asia before and everything is strange and wonderful:supermarkets and shopping mails,even the air- port seemed exotic!"wrote Ula Sickle,a choreographer from Poland on her blog under the name"chopstick diaries."Ula was one of the 18 foreign and domestic artists participating in a cultural exchange project called the Pointe to Point: Asia-Europe Dance Forum.It aims to empower aspiring young artists from Asia and Europe to reflect upon their views of

  5. Cytosolic SYT/SS18 isoforms are actin-associated proteins that function in matrix-specific adhesion.

    Directory of Open Access Journals (Sweden)

    Jaehong Kim

    Full Text Available SYT (SYnovial sarcoma Translocated gene or SS18 is widely produced as two isoforms, SYT/L and SYT/S, that are thought to function in the nucleus as transcriptional coactivators. Using isoform-specific antibodies, we detected a sizable pool of SYT isoforms in the cytosol where the proteins were organized into filamentous arrays. Actin and actin-associated proteins co-immunoprecipitated with SYT isoforms, which also co-sedimented and co-localized with the actin cytoskeleton in cultured cells and tissues. The association of SYT with actin bundles was extensive yet stopped short of the distal ends at focal adhesions. Disruption of the actin cytoskeleton also led to a breakdown of the filamentous organization of SYT isoforms in the cytosol. RNAi ablation of SYT/L alone or both isoforms markedly impaired formation of stress fibers and focal adhesions but did not affect formation of cortical actin bundles. Furthermore, ablation of SYT led to markedly impaired adhesion and spreading on fibronectin and laminin-111 but not on collagen types I or IV. These findings indicate that cytoplasmic SYT isoforms interact with actin filaments and function in the ability cells to bind and react to specific extracellular matrices.

  6. Activated PTHLH Coupling Feedback Phosphoinositide to G-Protein Receptor Signal-Induced Cell Adhesion Network in Human Hepatocellular Carcinoma by Systems-Theoretic Analysis

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2012-01-01

    Full Text Available Studies were done on analysis of biological processes in the same high expression (fold change ≥2 activated PTHLH feedback-mediated cell adhesion gene ontology (GO network of human hepatocellular carcinoma (HCC compared with the corresponding low expression activated GO network of no-tumor hepatitis/cirrhotic tissues (HBV or HCV infection. Activated PTHLH feedback-mediated cell adhesion network consisted of anaphase-promoting complex-dependent proteasomal ubiquitin-dependent protein catabolism, cell adhesion, cell differentiation, cell-cell signaling, G-protein-coupled receptor protein signaling pathway, intracellular transport, metabolism, phosphoinositide-mediated signaling, positive regulation of transcription, regulation of cyclin-dependent protein kinase activity, regulation of transcription, signal transduction, transcription, and transport in HCC. We proposed activated PTHLH coupling feedback phosphoinositide to G-protein receptor signal-induced cell adhesion network. Our hypothesis was verified by the different activated PTHLH feedback-mediated cell adhesion GO network of HCC compared with the corresponding inhibited GO network of no-tumor hepatitis/cirrhotic tissues, or the same compared with the corresponding inhibited GO network of HCC. Activated PTHLH coupling feedback phosphoinositide to G-protein receptor signal-induced cell adhesion network included BUB1B, GNG10, PTHR2, GNAZ, RFC4, UBE2C, NRXN3, BAP1, PVRL2, TROAP, and VCAN in HCC from GEO dataset using gene regulatory network inference method and our programming.

  7. Underwater adhesion: The barnacle way

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    of substrates in aqueous environment. The adhesive properties of the barnacle adhesive proteins have been utilized for various dental and medical purposes. These polyphenolic proteins are currently in demand as they are non-toxic biomaterial, highly effective...

  8. REDUCING NONSELECTIVE PROTEIN ADSORPTION AND CELL ADHESION ON POLYACRYLONITRILE FILMS BY COPOLYMERIZATION OF ACRYLONITRILE WITH α-ALLYL GLUCOSIDE

    Institute of Scientific and Technical Information of China (English)

    Rui-qiang Kou; Chao Qu; Zhi-kang Xu; You-yi Xu; Ke Yao

    2003-01-01

    In this work, the surface properties of novel sugar-containing polymers, α-allyl glucoside (AG)/acrylonitrile (AN)copolymers, were studied by contact angle, protein adsorption and cell adhesion measurements. It was found that the contact angle of the copolymer films decreased from 68° to 30° with the increase of AG content in the copolymer. The adsorption amount of bovine serum albumin (BSA) and the adhesive macrophage onto the film surface also decreased significantly with increasing α-allyl glucoside content from 0 to 42 wt% in the copolymer. These preliminary results reveal that both the hydrophilicity and the biocompatibility of polyacrylonitrile-based membranes could be improved by copolymerizing acrylonitrile with vinyl carbohydrates.

  9. Mechanical stimulation of C2C12 cells increases m-calpain expression, focal adhesion plaque protein degradation

    DEFF Research Database (Denmark)

    Grossi, Alberto; Karlsson, Anders H; Lawson, Moira Ann

    2008-01-01

    reorganization due to the activity of the ubiquitous proteolytic enzymes, calpains, has been reported. Whether there is a link between stretch- or load-induced signaling and calpain expression and activation is not known. Using a magnetic bead stimulation assay and C2C12 mouse myoblasts cell population, we have...... demonstrated that mechanical stimulation via laminin receptors leads to an increase in m-calpain expression, but no increase in the expression of other calpain isoforms. Our study revealed that after a short period of stimulation, m-calpain relocates into focal adhesion complexes and is followed by a breakdown...... of specific focal adhesion proteins previously identified as substrates for this enzyme. We show that stimulation also leads to an increase in calpain activity in these cells. These data support the pivotal role for m-calpain in the control of muscle precursor cell differentiation and thus strengthen the idea...

  10. Study on the Soy Protein-Based Wood Adhesive Modified by Hydroxymethyl Phenol

    Directory of Open Access Journals (Sweden)

    Hong Lei

    2016-07-01

    Full Text Available To explain the reason why using phenol-formaldehyde (PF resin improves the water resistance of soy-based adhesive, the performance of soy-based adhesive cross-linked with hydroxymethyl phenol (HPF and the reaction between HPF and a common dipeptide N-(2-l-alanyl-l-glutamine (AG being used as a model compound were studied in this paper. The DSC and DMA results indicated the reaction between HPF and soy-based adhesive. The soy-based adhesive cross-linked with HPF cured at a lower temperature than the adhesive without HPF. The former showed better mechanical performance and heat resistance than the latter. The ESI-MS, FT-IR and 13C-NMR results proved the reaction between HPF and AG. Because of the existence of branched ether groups in the 13C-NMR results of HPF/AG, the reaction between HPF and AG might mainly happened between hydroxymethyl groups and amino groups under a basic condition.

  11. In vivo modification of tyrosine residues in recombinant mussel adhesive protein by tyrosinase co-expression in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Choi Yoo

    2012-10-01

    Full Text Available Abstract Background In nature, mussel adhesive proteins (MAPs show remarkable adhesive properties, biocompatibility, and biodegradability. Thus, they have been considered promising adhesive biomaterials for various biomedical and industrial applications. However, limited production of natural MAPs has hampered their practical applications. Recombinant production in bacterial cells could be one alternative to obtain useable amounts of MAPs, although additional post-translational modification of tyrosine residues into 3,4-dihydroxyphenyl-alanine (Dopa and Dopaquinone is required. The superior properties of MAPs are mainly attributed to the introduction of quinone-derived intermolecular cross-links. To solve this problem, we utilized a co-expression strategy of recombinant MAP and tyrosinase in Escherichia coli to successfully modify tyrosine residues in vivo. Results A recombinant hybrid MAP, fp-151, was used as a target for in vivo modification, and a dual vector system of pET and pACYC-Duet provided co-expression of fp-151 and tyrosinase. As a result, fp-151 was over-expressed and mainly obtained from the soluble fraction in the co-expression system. Without tyrosinase co-expression, fp-151 was over-expressed in an insoluble form in inclusion bodies. The modification of tyrosine residues in the soluble-expressed fp-151 was clearly observed from nitroblue tetrazolium staining and liquid-chromatography-mass/mass spectrometry analyses. The purified, in vivo modified, fp-151 from the co-expression system showed approximately 4-fold higher bulk-scale adhesive strength compared to in vitro tyrosinase-treated fp-151. Conclusion Here, we reported a co-expression system to obtain in vivo modified MAP; additional in vitro tyrosinase modification was not needed to obtain adhesive properties and the in vivo modified MAP showed superior adhesive strength compared to in vitro modified protein. It is expected that this co-expression strategy will accelerate

  12. Biologically Inspired Polymer Micro-Patterned Adhesives

    Science.gov (United States)

    2008-11-01

    contained a volatile, hydrophilic phase.1 Another suggests that the pad secretion from the locust Locusta migratoria is an emulsion of lipidic nano...R.; Stierhof, Y. D.; Gorb, S.; Schwarz, U. Chemical composition of the attachment pad secretion of the locust Locusta migratoria . Insect Biochem

  13. Differential role of eDNA, proteins, and polysaccharides in cell-cell and cell-substrate adhesion by three Staphylococcus species

    DEFF Research Database (Denmark)

    Meyer, Rikke Louise; Okshevsky, Mira Ursula; Zeng, Guanghong

    on abiotic surfaces. We quantified initial adhesion, cell aggregation, and single-cell adhesion forces of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus xylosus in the presence and absence of DNase, dispersin, or subtilisin, which cleave extracellular DNA, polysaccharides and proteins...... valuable for designing new approaches to biofilm prevention. In this study, we combine microfluidic flow-cell studies with single-cell analyses to understand how polysaccharides, extracellular DNA (eDNA), and proteins contribute individually and in concert to mediate bacterial adhesion and aggregation...... eDNA and proteins are the most important adhesins for initiating S. aureus biofilms. S. epidermidis was strongly affected by all enzyme treatments, which in addition to impairing adhesion to glass, also prevented the formation of aggregates and streamers observed abundantly in control samples. One...

  14. Adhesions of extracellular surface-layer associated proteins in Lactobacillus M5-L and Q8-L.

    Science.gov (United States)

    Zhang, Yingchun; Xiang, Xinling; Lu, Qianhui; Zhang, Lanwei; Ma, Fang; Wang, Linlin

    2016-02-01

    Surface-layer associated proteins (SLAP) that envelop Lactobacillus paracasei ssp. paracasei M5-L and Lactobacillus casei Q8-L cell surfaces are involved in the adherence of these strain to the human intestinal cell line HT-29. To further elucidate some of the properties of these proteins, we assessed the yields and expressions of SLAP under different incubation conditions. An efficient and selective extraction of SLAP was obtained when cells of Lactobacillus were treated with 5 M LiCl at 37°C in aerobic conditions. The SLAP of Lactobacillus M5-L and Q8-L in cell extracts were visualized by SDS-PAGE and identified by Western blotting with sulfo-N-hydroxysuccinimide-biotin-labeled HT-29 cells as adhesion proteins. Atomic force microscopy contact imaging revealed that Lactobacillus strains M5-L and Q8-L normally display a smooth, homogeneous surface, whereas the surfaces of M5-L and Q8-L treated with 5 M LiCl were rough and more heterogeneous. Analysis of adhesion forces revealed that the initial adhesion forces of 1.41 and 1.28 nN obtained for normal Lactobacillus M5-L and Q8-L strains, respectively, decreased to 0.70 and 0.48 nN, respectively, following 5 M LiCl treatment. Finally, the dominant 45-kDa protein bands of Lactobacillus Q8-L and Lactobacillus M5-L were identified as elongation factor Tu and surface antigen, respectively, by liquid chromatography-tandem mass spectrometry.

  15. The Adhesion of Lactobacillus salivarius REN to a Human Intestinal Epithelial Cell Line Requires S-layer Proteins

    Science.gov (United States)

    Wang, Ran; Jiang, Lun; Zhang, Ming; Zhao, Liang; Hao, Yanling; Guo, Huiyuan; Sang, Yue; Zhang, Hao; Ren, Fazheng

    2017-01-01

    Lactobacillus salivarius REN, a novel probiotic isolated from Chinese centenarians, can adhere to intestinal epithelial cells and subsequently colonize the host. We show here that the surface-layer protein choline-binding protein A (CbpA) of L. salivarius REN was involved in adherence to the human colorectal adenocarcinoma cell line HT-29. Adhesion of a cbpA deletion mutant was significantly reduced compared with that of wild-type, suggesting that CbpA acts as an adhesin that mediates the interaction between the bacterium and its host. To identify the molecular mechanism of adhesion, we determined the crystal structure of a truncated form of CbpA that is likely involved in binding to its cell-surface receptor. The crystal structure identified CbpA as a peptidase of the M23 family whose members harbor a zinc-dependent catalytic site. Therefore, we propose that CbpA acts as a multifunctional surface protein that cleaves the host extracellular matrix and participates in adherence. Moreover, we identified enolase as the CbpA receptor on the surface of HT-29 cells. The present study reveals a new class of surface-layer proteins as well as the molecular mechanism that may contribute to the ability of L. salivarius REN to colonize the human gut. PMID:28281568

  16. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  17. The influence of cross-linking on protein-protein interactions in a marine adhesive: the case of two byssus plaque proteins from the blue mussel.

    Science.gov (United States)

    Fant, Camilla; Elwing, Hans; Höök, Fredrik

    2002-01-01

    The interaction between two proteins, Mefp-1 and Mefp-2, from the byssal plaque of the blue mussel, Mytilus edulis, was investigated using a quartz crystal microbalance with dissipation monitoring (QCM-D) technique. The challenge in using a surface-sensitive technique to investigate the interaction between two strongly adhesive proteins was met by coupling a biotinylated version of one of the proteins (b-Mefp-1) to an inert two-dimensional arrangement of streptavidin (SA) formed on top of a biotin-doped supported phospholipid bilayer. The interaction between Mefp-1 and Mefp-2 was further investigated by addition of Mefp-2 to SA-coupled b-Mefp-1, where the latter was either in the native state or cross-linked using sodium periodate (NaIO(4)), Cu(2+), or mushroom tyrosinase. With this coupling strategy it is shown that a requirement for attraction between the two proteins is that tyrosinase is used as the cross-linking agent of b-Mefp-1. By inhibiting the enzymatic activity of tyrosinase it is also shown that enzymatic activity is required for both efficient binding of tyrosinase to SA-coupled b-Mefp-1 as well as for the subsequent binding of Mefp-2. In contrast, spontaneous adsorption of Mefp-1 to a methyl-terminated (thiolated) gold surface followed by addition of Mefp-2 results in binding of Mefp-2 for all cross-linking agents. This suggests that cross-linking of Mefp-1 adsorbed on a solid surface induces structural changes in the adsorbed protein layer, resulting in exposure of free surface patches on which Mefp-2 binds.

  18. Adhesion of endothelial cells and adsorption of serum proteins on gas plasma-treated polytetrafluoroethylene

    NARCIS (Netherlands)

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

    1991-01-01

    From in vitro experiments it is known that human endothelial cells show poor adhesion to hydrophobic polymers. The hydrophobicity of vascular prostheses manufactured from Teflon® or Dacron® may be the reason why endothelialization of these grafts does not occur after implantation in humans. We modif

  19. Phosphoproteome Reveals an Atlas of Protein Signaling Networks During Osteoblast Adhesion

    NARCIS (Netherlands)

    Milani, Renato; Ferreira, Carmen V.; Granjeiro, Jose M.; Paredes-Gamero, Edgar J.; Silva, Rodrigo A.; Justo, Giselle Z.; Nader, Helena B.; Galembeck, Eduardo; Peppelenbosch, Maikel P.; Aoyama, Hiroshi; Zambuzzi, Willian F.

    2010-01-01

    Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important r

  20. Phosphoproteome Reveals an Atlas of Protein Signaling Networks During Osteoblast Adhesion

    NARCIS (Netherlands)

    Milani, Renato; Ferreira, Carmen V.; Granjeiro, Jose M.; Paredes-Gamero, Edgar J.; Silva, Rodrigo A.; Justo, Giselle Z.; Nader, Helena B.; Galembeck, Eduardo; Peppelenbosch, Maikel P.; Aoyama, Hiroshi; Zambuzzi, Willian F.

    2010-01-01

    Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important

  1. Differential Impact of Plasma Proteins on the Adhesion Efficiency of Vascular-Targeted Carriers (VTCs) in Blood of Common Laboratory Animals.

    Science.gov (United States)

    Namdee, Katawut; Sobczynski, Daniel J; Onyskiw, Peter J; Eniola-Adefeso, Omolola

    2015-12-16

    Vascular-targeted carrier (VTC) interaction with human plasma is known to reduce targeted adhesion efficiency in vitro. However, the role of plasma proteins on the adhesion efficiency of VTCs in laboratory animals remains unknown. Here, in vitro blood flow assays are used to explore the effects of plasma from mouse, rabbit, and porcine on VTC adhesion. Porcine blood exhibited a strong negative plasma effect on VTC adhesion while no significant plasma effect was found with rabbit and mouse blood. A brush density poly(ethylene glycol) (PEG) on VTCs was effective at improving adhesion of microsized, but not nanosized, VTCs in porcine blood. Overall, the results suggest that porcine models, as opposed to mouse, can serve as better models in preclinical research for predicting the in vivo functionality of VTCs for use in humans. These considerations hold great importance for the design of various pharmaceutical products and development of reliable drug delivery systems.

  2. A role for the retinoblastoma protein as a regulator of mouse osteoblast cell adhesion: implications for osteogenesis and osteosarcoma formation.

    Directory of Open Access Journals (Sweden)

    Bernadette Sosa-García

    Full Text Available The retinoblastoma protein (pRb is a cell cycle regulator inactivated in most human cancers. Loss of pRb function results from mutations in the gene coding for pRb or for any of its upstream regulators. Although pRb is predominantly known as a cell cycle repressor, our data point to additional pRb functions in cell adhesion. Our data show that pRb regulates the expression of a wide repertoire of cell adhesion genes and regulates the assembly of the adherens junctions required for cell adhesion. We conducted our studies in osteoblasts, which depend on both pRb and on cell-to-cell contacts for their differentiation and function. We generated knockout mice in which the RB gene was excised specifically in osteoblasts using the cre-lox P system and found that osteoblasts from pRb knockout mice did not assemble adherens junction at their membranes. pRb depletion in wild type osteoblasts using RNAi also disrupted adherens junctions. Microarrays comparing pRb-expressing and pRb-deficient osteoblasts showed that pRb controls the expression of a number of cell adhesion genes, including cadherins. Furthermore, pRb knockout mice showed bone abnormalities consistent with osteoblast adhesion defects. We also found that pRb controls the function of merlin, a well-known regulator of adherens junction assembly, by repressing Rac1 and its effector Pak1. Using qRT-PCR, immunoblots, co-immunoprecipitation assays, and immunofluorescent labeling, we observed that pRb loss resulted in Rac1 and Pak1 overexpression concomitant with merlin inactivation by Pak1, merlin detachment from the membrane, and adherens junction loss. Our data support a pRb function in cell adhesion while elucidating the mechanism for this function. Our work suggests that in some tumor types pRb inactivation results in both a loss of cell cycle control that promotes initial tumor growth as well as in a loss of cell-to-cell contacts, which contributes to later stages of metastasis.

  3. β Integrin-like protein-mediated adhesion and its disturbances during cell cultivation of the mussel Mytilus trossulus.

    Science.gov (United States)

    Maiorova, Mariia A; Odintsova, Nelly A

    2015-08-01

    In this study, we focus on the specific contribution of β integrin-like protein to adhesion-mediated events in molluscan larval cells in culture that could not have been investigated within the whole animal. An analysis of disturbances to cell-substratum adhesion, caused by the integrin receptor inhibiting Arg-Gly-Asp-Ser (RGDS)-peptide, the Ca(2+)/Mg(2+)-chelators and the stress influence of freezing-thawing, reveals that all these factors resulted in the partial destruction of the integrin-extracellular matrix (ECM) interaction in culture and, in particular, changes in the distribution and relative abundance of β integrin-positive cells. The experiments, carried out on selected substrates, found that β integrin-positive cells demonstrate different affinities for the substrates. This finding further supports the assumption that epithelial differentiation in cultivated cells of larval Mytilus may be mediated by β integrin-like proteins via binding to laminin; direct binding to other components of the ECM could not be demonstrated. The mussel β integrin-positive cells are not involved in myogenic or neuronal differentiation on any of the substrates but part of them has tubulin-positive cilia, forming some epithelia-like structures. Our data indicate that β integrin-positive cells are able to proliferate in vitro which suggests that they could participate in renewing the digestive epithelium in larvae. The findings provide evidence that the distribution pattern of β integrin-like protein depends on the cell type and the factors influencing the adhesion.

  4. The adhesive protein of Choromytilus chorus (Molina, 1782) and Aulacomya ater (Molina, 1782): a proline-rich and a glycine-rich polyphenolic protein.

    Science.gov (United States)

    Burzio, L A; Saéz, C; Pardo, J; Waite, J H; Burzio, L O

    2000-06-15

    The adhesive polyphenolic proteins from Aulacomya ater and Choromytilus chorus with apparent molecular masses of 135000 and 105000, respectively, were digested with trypsin and the peptides produced resolved by reversed phase liquid chromatography. About 5 and 12 major peptides were obtained from the protein of A. ater and C. chorus, respectively. The major peptides were purified by reverse-phase chromatography and the amino acid sequence indicates that both polyphenolic proteins consisted of repeated sequence motifs in their primary structure. The major peptides of A. ater contain seven amino acids corresponding to the consensus sequence AGYGGXK, whereas the tyrosine was always found as 3, 4-dihydroxyphenylalanine (Dopa), the X residue in position 6 was either valine, leucine or isoleucine, and the carboxy terminal was either lysine or hydroxylysine. On the other hand, the major peptides of C. chorus ranged in size from 6 to 21 amino acids and the majority correspond to the consensus sequence AKPSKYPTGYKPPVK. Both proteins differ markedly in the sequence of their tryptic peptides, but they share the common characteristics of other adhesive proteins in having a tandem sequence repeat in their primary structure.

  5. Resistance to protein adsorption and adhesion of fibroblasts on nanocrystalline diamond films: the role of topography and boron doping.

    Science.gov (United States)

    Alcaide, María; Papaioannou, Stavros; Taylor, Andrew; Fekete, Ladislav; Gurevich, Leonid; Zachar, Vladimir; Pennisi, Cristian Pablo

    2016-05-01

    Boron-doped nanocrystalline diamond (BNCD) films exhibit outstanding electrochemical properties that make them very attractive for the fabrication of electrodes for novel neural interfaces and prosthetics. In these devices, the physicochemical properties of the electrode materials are critical to ensure an efficient long-term performance. The aim of this study was to investigate the relative contribution of topography and doping to the biological performance of BNCD films. For this purpose, undoped and boron-doped NCD films were deposited on low roughness (LR) and high roughness (HR) substrates, which were studied in vitro by means of protein adsorption and fibroblast growth assays. Our results show that BNCD films significantly reduce the adsorption of serum proteins, mostly on the LR substrates. As compared to fibroblasts cultured on LR BNCD films, cells grown on the HR BNCD films showed significantly reduced adhesion and lower growth rates. The mean length of fibronectin fibrils deposited by the cells was significantly increased in the BNCD coated substrates, mainly in the LR surfaces. Overall, the largest influence on protein adsorption, cell adhesion, proliferation, and fibronectin deposition was due to the underlying sub-micron topography, with little or no influence of boron doping. In perspective, BNCD films displaying surface roughness in the submicron range may be used as a strategy to reduce the fibroblast growth on the surface of neural electrodes.

  6. Analysis of Phosphorylation-dependent Protein Interactions of Adhesion and Degranulation Promoting Adaptor Protein (ADAP) Reveals Novel Interaction Partners Required for Chemokine-directed T cell Migration.

    Science.gov (United States)

    Kuropka, Benno; Witte, Amelie; Sticht, Jana; Waldt, Natalie; Majkut, Paul; Hackenberger, Christian P R; Schraven, Burkhart; Krause, Eberhard; Kliche, Stefanie; Freund, Christian

    2015-11-01

    Stimulation of T cells leads to distinct changes of their adhesive and migratory properties. Signal propagation from activated receptors to integrins depends on scaffolding proteins such as the adhesion and degranulation promoting adaptor protein (ADAP)(1). Here we have comprehensively investigated the phosphotyrosine interactome of ADAP in T cells and define known and novel interaction partners of functional relevance. While most phosphosites reside in unstructured regions of the protein, thereby defining classical SH2 domain interaction sites for master regulators of T cell signaling such as SLP76, Fyn-kinase, and NCK, other binding events depend on structural context. Interaction proteomics using different ADAP constructs comprising most of the known phosphotyrosine motifs as well as the structured domains confirm that a distinct set of proteins is attracted by pY571 of ADAP, including the ζ-chain-associated protein kinase of 70 kDa (ZAP70). The interaction of ADAP and ZAP70 is inducible upon stimulation either of the T cell receptor (TCR) or by chemokine. NMR spectroscopy reveals that the N-terminal SH2 domains within a ZAP70-tandem-SH2 construct is the major site of interaction with phosphorylated ADAP-hSH3(N) and microscale thermophoresis (MST) indicates an intermediate binding affinity (Kd = 2.3 μm). Interestingly, although T cell receptor dependent events such as T cell/antigen presenting cell (APC) conjugate formation and adhesion are not affected by mutation of Y571, migration of T cells along a chemokine gradient is compromised. Thus, although most phospho-sites in ADAP are linked to T cell receptor related functions we have identified a unique phosphotyrosine that is solely required for chemokine induced T cell behavior.

  7. Cdc42 Effector Protein 2 (XCEP2 is required for normal gastrulation and contributes to cellular adhesion in Xenopus laevis

    Directory of Open Access Journals (Sweden)

    Nelson Richard W

    2004-10-01

    Full Text Available Abstract Background Rho GTPases and their downstream effector proteins regulate a diverse array of cellular processes during embryonic development, including reorganization of cytoskeletal architecture, cell adhesion, and transcription. Changes in the activation state of Rho GTPases are converted into changes in cellular behavior by a diversity of effector proteins, which are activated in response to changes in the GTP binding state of Rho GTPases. In this study we characterize the expression and function of one such effector, XCEP2, that is present during gastrulation stages in Xenopus laevis. Results In a search for genes whose expression is regulated during early stages of embryonic development in Xenopus laevis, a gene encoding a Rho GTPase effector protein (Xenopus Cdc42 effector protein 2, or XCEP2 was isolated, and found to be highly homologous, but not identical, to a Xenopus sequence previously submitted to the Genbank database. These two gene sequences are likely pseudoalleles. XCEP2 mRNA is expressed at constant levels until mid- to late- gastrula stages, and then strongly down-regulated at late gastrula/early neurula stages. Injection of antisense morpholino oligonucleotides directed at one or both pseudoalleles resulted in a significant delay in blastopore closure and interfered with normal embryonic elongation, suggesting a role for XCEP2 in regulating gastrulation movements. The morpholino antisense effect could be rescued by co-injection with a morpholino-insensitive version of the XCEP2 mRNA. Antisense morpholino oligonucleotides were found to have no effect on mesodermal induction, suggesting that the observed effects were due to changes in the behavior of involuting cells, rather than alterations in their identity. XCEP2 antisense morpholino oligonucleotides were also observed to cause complete disaggregation of cells composing animal cap explants, suggesting a specific role of XCEP2 in maintenance or regulation of cell

  8. Melanin and Melanin-Related Polymers as Materials with Biomedical and Biotechnological Applications—Cuttlefish Ink and Mussel Foot Proteins as Inspired Biomolecules

    Directory of Open Access Journals (Sweden)

    Francisco Solano

    2017-07-01

    Full Text Available The huge development of bioengineering during the last years has boosted the search for new bioinspired materials, with tunable chemical, mechanical, and optoelectronic properties for the design of semiconductors, batteries, biosensors, imaging and therapy probes, adhesive hydrogels, tissue restoration, photoprotectors, etc. These new materials should complement or replace metallic or organic polymers that cause cytotoxicity and some adverse health effects. One of the most interesting biomaterials is melanin and synthetic melanin-related molecules. Melanin has a controversial molecular structure, dependent on the conditions of polymerization, and therefore tunable. It is found in animal hair and skin, although one of the common sources is cuttlefish (Sepia officinalis ink. On the other hand, mussels synthesize adhesive proteins to anchor these marine animals to wet surfaces. Both melanin and mussel foot proteins contain a high number of catecholic residues, and their properties are related to these groups. Dopamine (DA can easily polymerize to get polydopamine melanin (PDAM, that somehow shares properties with melanin and mussel proteins. Furthermore, PDAM can easily be conjugated with other components. This review accounts for the main aspects of melanin, as well as DA-based melanin-like materials, related to their biomedical and biotechnological applications.

  9. Melanin and Melanin-Related Polymers as Materials with Biomedical and Biotechnological Applications-Cuttlefish Ink and Mussel Foot Proteins as Inspired Biomolecules.

    Science.gov (United States)

    Solano, Francisco

    2017-07-18

    The huge development of bioengineering during the last years has boosted the search for new bioinspired materials, with tunable chemical, mechanical, and optoelectronic properties for the design of semiconductors, batteries, biosensors, imaging and therapy probes, adhesive hydrogels, tissue restoration, photoprotectors, etc. These new materials should complement or replace metallic or organic polymers that cause cytotoxicity and some adverse health effects. One of the most interesting biomaterials is melanin and synthetic melanin-related molecules. Melanin has a controversial molecular structure, dependent on the conditions of polymerization, and therefore tunable. It is found in animal hair and skin, although one of the common sources is cuttlefish (Sepia officinalis) ink. On the other hand, mussels synthesize adhesive proteins to anchor these marine animals to wet surfaces. Both melanin and mussel foot proteins contain a high number of catecholic residues, and their properties are related to these groups. Dopamine (DA) can easily polymerize to get polydopamine melanin (PDAM), that somehow shares properties with melanin and mussel proteins. Furthermore, PDAM can easily be conjugated with other components. This review accounts for the main aspects of melanin, as well as DA-based melanin-like materials, related to their biomedical and biotechnological applications.

  10. Mussel-inspired Fluoro-Polydopamine Functionalization of Titanium Dioxide Nanowires for Polymer Nanocomposites with Significantly Enhanced Energy Storage Capability

    OpenAIRE

    Guanyao Wang; Xingyi Huang; Pingkai Jiang

    2017-01-01

    High-dielectric-constant polymer nanocomposites are demonstrated to show great promise as energy storage materials. However, the large electrical mismatch and incompatibility between nanofillers and polymer matrix usually give rise to significantly reduced breakdown strength and weak energy storage capability. Therefore, rational selection and elaborate functionalization of nanofillers to optimize the performance of polymer nanocomposites are vital. Herein, inspired by adhesive proteins in mu...

  11. Adhesion-Linked Protein Tyrosine Phosphatases, Morphogenesis and Breast Cancer Progression

    Science.gov (United States)

    2006-07-01

    Weaver, V.M. Force and the third dimension, Invited Symposium Speaker Gordon Conference on Signaling by Adhesion Receptors, Mount Holyoke College...hope to use to pull down/substrate identification studies as well as for immunostaining purposes. In this regard we intend in the future to assess the... identification and characterization of PTPMEG1 substrates in normal and transformed MECs. Finally, one of the goals of the DOD IDEA awards is to permit

  12. α2-Macroglobulin Can Crosslink Multiple Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) Molecules and May Facilitate Adhesion of Parasitized Erythrocytes

    DEFF Research Database (Denmark)

    Stevenson, Liz; Laursen, Erik; Cowan, Graeme J;

    2015-01-01

    Rosetting, the adhesion of Plasmodium falciparum-infected erythrocytes to uninfected erythrocytes, involves clonal variants of the parasite protein P. falciparum erythrocyte membrane protein 1 (PfEMP1) and soluble serum factors. While rosetting is a well-known phenotypic marker of parasites...

  13. Adhesive properties, extracellular protein production, and metabolism in the Lactobacillus rhamnosus GG strain when grown in the presence of mucin.

    Science.gov (United States)

    Sanchez, Borja; Saad, Naima; Schmitter, Jean-Marie; Bressollier, Philippe; Urdaci, Maria C

    2010-06-01

    This paper examines the probiotic bacterium Lactobacillus rhamnosus GG, and how it reacts to the presence of mucin in its extracellular milieu. Parameters studied included cell clustering, adhesion to mucin, extracellular protein production, and formation of final metabolites. L. rhamnosus GG was found to grow efficiently in the presence of glucose, N-acetylglucosamine, or mucin (partially purified or purified) as sole carbon sources. However, it was unable to grow using other mucin constituents, such as fucose or glucuronic acid. Mucin induced noticeable changes in all the parameters studied when compared with growth using glucose, including in the formation of cell clusters, which were easily disorganized with trypsin. Mucin increased adhesion of the bacterium, and modulated the production of extracellular proteins. SDS-PAGE revealed that mucin was not degraded during L. rhamnosus GG growth, suggesting that this bacterium is able to partially use the glucidic moiety of glycoprotein. This study goes some way towards developing an understanding of the metabolic and physiological changes that L. rhamnosus GG undergoes within the human gastrointestinal tract.

  14. Green spermatozoa illuminate a 30-year-old model:sperm-egg adhesion involves intra-acrosomal proteins

    Institute of Scientific and Technical Information of China (English)

    Steve Tardif

    2011-01-01

    @@ Fertilisation in mammals involves many synchronized steps including spermegg adhesion.Prior to sperm-oolemma fusion,spermatozoa need to undergo the acrosome reaction (AR) or exocytosis.The universal belief,for many years,has been that the AR was initiated upon binding to the zona pellucida (ZP).As such acrosomal proteins were not thought to be involved in the primary contact with the ZP.These proteins were only suggested to be biologically relevant once the sperm were attached to the ZP and during subsequent events.However,recent data in the mouse have unequivocally demonstrated that spermatozoa can begin exocytosis before contact with ZP.1 It is a remarkable finding as not only will the interpretation of the interaction between sperm and cumulus cells need to be revised,but the processes of capacitation,vesiculation and exposure of acrosomal content need reexamination.

  15. Novel locomotion via biological inspiration

    Science.gov (United States)

    Quinn, Roger D.; Boxerbaum, Alexander; Palmer, Luther; Chiel, Hillel; Diller, Eric; Hunt, Alexander; Bachmann, Richard

    2011-05-01

    Animal behavioral, physiological and neurobiological studies are providing a wealth of inspirational data for robot design and control. Several very different biologically inspired mobile robots will be reviewed. A robot called DIGbot is being developed that moves independent of the direction of gravity using Distributed Inward Gripping (DIG) as a rapid and robust attachment mechanism observed in climbing animals. DIGbot is an 18 degree of freedom hexapod with onboard power and control systems. Passive compliance in its feet, which is inspired by the flexible tarsus of the cockroach, increases the robustness of the adhesion strategy and enables DIGbot to execute large steps and stationary turns while walking on mesh screens. A Whegs™ robot, inspired by insect locomotion principles, is being developed that can be rapidly reconfigured between tracks and wheel-legs and carry GeoSystems Zipper Mast. The mechanisms that cause it to passively change its gait on irregular terrain have been integrated into its hubs for a compact and modular design. The robot is designed to move smoothly on moderately rugged terrain using its tracks and run on irregular terrain and stairs using its wheel-legs. We are also developing soft bodied robots that use peristalsis, the same method of locomotion earthworms use. We present a technique of using a braided mesh exterior to produce fluid waves of motion along the body of the robot that increase the robot's speed relative to previous designs. The concept is highly scalable, for endoscopes to water, oil or gas line inspection.

  16. Bioactivity of immobilized hyaluronic acid derivatives regarding protein adsorption and cell adhesion

    DEFF Research Database (Denmark)

    Köwitsch, Alexander; Yang, Yuan; Ma, Ning

    2011-01-01

    Hyaluronic acid (HA) was chemically modified either by oxidation to obtain aldehyde-HA (aHA) or 3,3'-dithiobis(propanoic hydrazide) to obtain thiol-HA (tHA) that was covalently immobilized on model substrata such as amino-terminated surfaces or gold. Knowledge about the effect of modification...... affects cell growth and differentiation. A lower number and spreading of cells were observed on HA-modified surfaces compared to amino- and vinyl-terminated glass and silicon surfaces. Immunofluorescence microscopy also revealed that adhesion of fibroblast plated on HA-modified surfaces was mediated...

  17. Corynebacterium diphtheriae invasion-associated protein (DIP1281 is involved in cell surface organization, adhesion and internalization in epithelial cells

    Directory of Open Access Journals (Sweden)

    Rheinlaender Johannes

    2010-01-01

    Full Text Available Abstract Background Corynebacterium diphtheriae, the causative agent of diphtheria, is well-investigated in respect to toxin production, while little is known about C. diphtheriae factors crucial for colonization of the host. In this study, we investigated the function of surface-associated protein DIP1281, previously annotated as hypothetical invasion-associated protein. Results Microscopic inspection of DIP1281 mutant strains revealed an increased size of the single cells in combination with an altered less club-like shape and formation of chains of cells rather than the typical V-like division forms or palisades of growing C. diphtheriae cells. Cell viability was not impaired. Immuno-fluorescence microscopy, SDS-PAGE and 2-D PAGE of surface proteins revealed clear differences of wild-type and mutant protein patterns, which were verified by atomic force microscopy. DIP1281 mutant cells were not only altered in shape and surface structure but completely lack the ability to adhere to host cells and consequently invade these. Conclusions Our data indicate that DIP1281 is predominantly involved in the organization of the outer surface protein layer rather than in the separation of the peptidoglycan cell wall of dividing bacteria. The adhesion- and invasion-negative phenotype of corresponding mutant strains is an effect of rearrangements of the outer surface.

  18. GPR116, an adhesion G-protein-coupled receptor, promotes breast cancer metastasis via the Gαq-p63RhoGEF-Rho GTPase pathway.

    Science.gov (United States)

    Tang, Xiaolong; Jin, Rongrong; Qu, Guojun; Wang, Xiu; Li, Zhenxi; Yuan, Zengjin; Zhao, Chen; Siwko, Stefan; Shi, Tieliu; Wang, Ping; Xiao, Jianru; Liu, Mingyao; Luo, Jian

    2013-10-15

    Adhesion G-protein-coupled receptors (GPCR), which contain adhesion domains in their extracellular region, have been found to play important roles in cell adhesion, motility, embryonic development, and immune response. Because most adhesion molecules with adhesion domains have vital roles in cancer metastasis, we speculated that adhesion GPCRs are potentially involved in cancer metastasis. In this study, we identified GPR116 as a novel regulator of breast cancer metastasis through expression and functional screening of the adhesion GPCR family. We found that knockdown of GPR116 in highly metastatic (MDA-MB-231) breast cancer cells suppressed cell migration and invasion. Conversely, ectopic GPR116 expression in poorly metastatic (MCF-7 and Hs578T) cells promoted cell invasion. We further showed that knockdown of GPR116 inhibited breast cancer cell metastasis in two mammary tumor metastasis mouse models. Moreover, GPR116 modulated the formation of lamellipodia and actin stress fibers in cells in a RhoA- and Rac1-dependent manner. At a molecular level, GPR116 regulated cell motility and morphology through the Gαq-p63RhoGEF-RhoA/Rac1 pathway. The biologic significance of GPR116 in breast cancer is substantiated in human patient samples, where GPR116 expression is significantly correlated with breast tumor progression, recurrence, and poor prognosis. These findings show that GPR116 is crucial for the metastasis of breast cancer and support GPR116 as a potential prognostic marker and drug target against metastatic human breast cancer. ©2013 AACR.

  19. Three glycosylated serine-rich repeat proteins play a pivotal role in adhesion and colonization of the pioneer commensal bacterium, Streptococcus salivarius.

    Science.gov (United States)

    Couvigny, Benoit; Lapaque, Nicolas; Rigottier-Gois, Lionel; Guillot, Alain; Chat, Sophie; Meylheuc, Thierry; Kulakauskas, Saulius; Rohde, Manfred; Mistou, Michel-Yves; Renault, Pierre; Doré, Joel; Briandet, Romain; Serror, Pascale; Guédon, Eric

    2017-09-01

    Bacterial adhesion is a critical step for colonization of the host. The pioneer colonizer and commensal bacterium of the human gastrointestinal tract, Streptococcus salivarius, has strong adhesive properties but the molecular determinants of this adhesion remain uncharacterized. Serine-rich repeat (SRR) glycoproteins are a family of adhesins that fulfil an important role in adhesion. In general, Gram-positive bacterial genomes have a unique SRR glycoprotein-encoding gene. We demonstrate that S. salivarius expresses three large and glycosylated surface-exposed proteins - SrpA, SrpB and SrpC - that show characteristics of SRR glycoproteins and are secreted through the accessory SecA2/Y2 system. Two glycosyltransferases - GtfE/F - encoded outside of the secA2/Y2 locus, unusually, perform the first step of the sequential glycosylation process, which is crucial for SRR activity. We show that SrpB and SrpC play complementary adhesive roles involved in several steps of the colonization process: auto-aggregation, biofilm formation and adhesion to a variety of host epithelial cells and components. We also show that at least one of the S. salivarius SRR glycoproteins is important for colonization in mice. SrpA, SrpB and SrpC are the main factors underlying the multifaceted adhesion of S. salivarius and, therefore, play a major role in host colonization. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  20. Inhibition of PMA-induced endothelial cell activation and adhesion by over-expression of domain negative IκBα protein

    Institute of Scientific and Technical Information of China (English)

    Jian-Feng Wei; Ke Sun; Shi-Guo Xu; Hai-Yang Xie; Shu-Sen Zheng

    2005-01-01

    AIM: NF-κB, regulate the expression of cytokine-inducible genes involving immune and inflammatory responses, will be potential therapy approach for allograft from rejection. In this study, we use pCMV-IκBαM vector to inhibit NF-κB activation and investigate the effect of pCMV-IκBαM in inhibition of T cells adhesion to endothelial cells. METHODS: The NF-κB activity was detected with pNF-κB reporter gene and electrophoretic mobility shift assay. Expression of cell surface molecules was detected by RT-PCR and flow cytometer. The cell-cell adhesion assay was performed to determine the effect of pCMV-IκBαM in inhibition of T cells adhesion to endothelial cells. RESULTS: We could find that NF-κB activity is inhibited by over-expression of non-degraded IκBα protein. Expression of adhesion molecules like ICAM-1, VCAM-1, and P-selectin as well as cell-cell adhesion were inhibited significantly by transfection of the pCMV-IκBαM vector. CONCLUSION: Our results indicate that the pCMVIκBαM, which inhibit the activity of NF-κB through over-expression of non-degraded IκBα protein, can be used for gene therapy in diseases involving NF-κB activation abnormally like organ transplantation via inhibiting cell adhesion.

  1. Parathyroid hormone-related protein (PTHrP) modulates adhesion, migration and invasion in bone tumor cells.

    Science.gov (United States)

    Mak, Isabella W Y; Turcotte, Robert E; Ghert, Michelle

    2013-07-01

    Parathyroid-hormone-related protein (PTHrP) has been shown to be an important factor in osteolysis in the setting of metastatic carcinoma to the bone. However, PTHrP may also be central in the setting of primary bone tumors. Giant cell tumor of bone (GCT) is an aggressive osteolytic bone tumor characterized by osteoclast-like giant cells that are recruited by osteoblast-like stromal cells. The stromal cells of GCT are well established as the only neoplastic element of the tumor, and we have previously shown that PTHrP is highly expressed by these cells both in vitro and in vivo. We have also found that the stromal cells exposed to a monoclonal antibody to PTHrP exhibited rapid plate detachment and quickly died in vitro. Therefore, PTHrP may serve in an autocrine manner to increase cell proliferation and promote invasive properties in GCT. The purpose of this study was to use transcriptomic microarrays and functional assays to examine the effects of PTHrP neutralization on cell adhesion, migration and invasion. Microarray and proteomics data identified genes that were differentially expressed in GCT stromal cells under various PTHrP treatment conditions. Treatment of GCT stromal cells with anti-PTHrP antibodies showed a change in the expression of 13 genes from the integrin family relative to the IgG control. Neutralization of PTHrP reduced cell migration and invasion as evidenced by functional assays. Adhesion and anoikis assays demonstrated that although PTHrP neutralization inhibits cell adhesion properties, cell detachment related to PTHrP neutralization did not result in associated cell death, as expected in mesenchymal stromal cells. Based on the data presented herein, we conclude that PTHrP excreted by GCT stromal cells increases bone tumor cell local invasiveness and migration.

  2. Enantiopure chiral poly(glycerol methacrylate) self-assembled monolayers knock down protein adsorption and cell adhesion.

    Science.gov (United States)

    Li, Zheng; Köwitsch, Alexander; Zhou, Guoying; Groth, Thomas; Fuhrmann, Bodo; Niepel, Marcus; Amado, Elkin; Kressler, Jörg

    2013-10-01

    Chirality plays a fundamental role not only in biological systems, but also in synthetic materials intended for bio-applications. Self-assembled monolayers (SAMs) are prepared on gold surfaces through a "grafting to" method from racemic or enantiopure chiral poly(glycerol methacrylate)s (PGMA(rac), PGMA(R), and PGMA(S)), having a thiol endgroup. Such SAMs constitute a chemically and structurally well-defined model substrate for studying protein adsorption and cell adhesion as a function of the polymer chirality. Surface plasmon resonance measurements reveal that PGMA SAMs greatly reduce the adsorption of bovine serum albumin (BSA) compared to bare gold surfaces. Interestingly, enantiopure SAMs based on PGMA(R) or PGMA(S) show a significantly larger reduction in BSA adsorption than PGMA(rac)-covered surfaces. Studies with the monocytic cell line THP-1 show a similar relationship between enantiopurity of PGMA SAMs and the extent of cell adhesion. Ellipsometry and Raman spectroscopy measurements indicate that SAMs formed by PGMA(rac) have a higher grafting density compared to SAMs of PGMA(R) and PGMA(S). This seems to be due to the ability of PGMA(rac) to form more intermolecular hydrogen bonds among polymer chains compared to the enantiopure PGMAs. Circular dichroism spectroscopy provide evidence that enantiopure polymers adopt a chiral ordered conformation, most likely helical, in aqueous solutions. It is concluded that a higher water content of SAMs formed by enantiopure PGMA(S) and PGMA(R) SAMs arises from the macromolecular chiral conformation adopted by their enantiopure PGMA chains, and it is the decisive reason for the reduced BSA adsorption and cell adhesion as compared to PGMA(rac) SAMs.

  3. Nicotine stimulates adhesion molecular expression via calcium influx and mitogen-activated protein kinases in human endothelial cells.

    Science.gov (United States)

    Wang, Yajing; Wang, Zhaoxia; Zhou, Ying; Liu, Liming; Zhao, Yangxing; Yao, Chenjiang; Wang, Lianyun; Qiao, Zhongdong

    2006-02-01

    To evaluate the effect of nicotine on endothelium dysfunction and development of vascular diseases, we investigated the influence on adhesion molecular expression mediated by nicotine and the mechanism of this effect in human umbilical vein endothelial cells (HUVECs). The result showed that nicotine could induce surface/soluble vascular cell adhesion molecule (VCAM-1) and endothelial selectin (E-selectin) expression in a time-response decline manner and the peak appeared at 15 min. This action could be mediated by mitogen-activated protein kinase/extracellular signal regulated kinase 1/2 (MAPK/ERK1/2) and MAPK/p38 because their activation could be distinctly blocked by MAPK inhibitors, PD098059 or SB203580. Mecamylamine (non-selective nicotinic receptor inhibitor), alpha-bungarotoxin (alpha7 nicotinic receptor inhibitor) could block Ca2+ accumulation, and then, prevented the phosphorylation on ERK1/2 and p38. They also inhibited the surface/soluble VCAM-1, E-selectin production of HUVECs modulated by nicotine. Therefore, we concluded that: (i) nicotine obviously up-regulates VCAM-1 and E-selectin expression at 15 min in HUVECs, (ii) nicotine activates HUVECs triggered by the ERK1/2 and p38 phosphorylation with an involvement of intracellular calcium mobilization chiefly mediated by alpha7 nicotinic receptor, (iii) intracellular Ca2+ activates a sequential pathway from alpha7 nicotinic receptor to the phosphorylation of ERK1/2, p38. These elucidate that nicotine activates HUVECs through fast signal transduction pathway and arguments their capacity of adhesion molecular production. Further more nicotine may contribute its influence to the progression of vascular disease such as atherosclerotic lesion.

  4. Unusual adhesive production system in the barnacle Lepas anatifera: an ultrastructural and histochemical investigation.

    Science.gov (United States)

    Jonker, Jaimie-Leigh; von Byern, Janek; Flammang, Patrick; Klepal, Waltraud; Power, Anne Marie

    2012-12-01

    Adhesives that are naturally produced by marine organisms are potential sources of inspiration in the search for medical adhesives. Investigations of barnacle adhesives are at an early stage but it is becoming obvious that barnacles utilize a unique adhesive system compared to other marine organisms. The current study examined the fine structure and chemistry of the glandular system that produces the adhesive of the barnacle Lepas anatifera. All components for the glue originated from large single-cell glands (70-180 μm). Staining (including immunostaining) showed that L-3,4-dihydroxyphenylalanine and phosphoserine were not present in the glue producing tissues, demonstrating that the molecular adhesion of barnacles differs from all other permanently gluing marine animals studied to date. The glandular tissue and adhesive secretion primarily consisted of slightly acidic proteins but also included some carbohydrate. Adhesive proteins were stored in cytoplasmic granules adjacent to an intracellular drainage canal (ICC); observations implicated both merocrine and apocrine mechanisms in the transport of the secretion from the cell cytoplasm to the ICC. Inside the ICC, the secretion was no longer contained within granules but was a flocculent material which became "clumped" as it traveled through the canal network. Hemocytes were not seen within the adhesive "apparatus" (comprising of the glue producing cells and drainage canals), nor was there any structural mechanism by which additions such as hemocytes could be made to the secretion. The unicellular adhesive gland in barnacles is distinct from multicellular adhesive systems observed in marine animals such as mussels and tubeworms. Because the various components are not physically separated in the apparatus, the barnacle adhesive system appears to utilize completely different and unknown mechanisms for maintaining the liquid state of the glue within the body, as well as unidentified mechanisms for the conversion of

  5. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics

    NARCIS (Netherlands)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert; Dekker, Frans

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain

  6. Protein structure similarity clustering (PSSC) and natural product structure as inspiration sources for drug development and chemical genomics

    NARCIS (Netherlands)

    Dekker, Frank J; Koch, Marcus A; Waldmann, Herbert; Dekker, Frans

    2005-01-01

    Finding small molecules that modulate protein function is of primary importance in drug development and in the emerging field of chemical genomics. To facilitate the identification of such molecules, we developed a novel strategy making use of structural conservatism found in protein domain architec

  7. Preserving the adhesion of catechol-conjugated hydrogels by thiourea-quinone coupling.

    Science.gov (United States)

    Xu, Yang J; Wei, Kongchang; Zhao, Pengchao; Feng, Qian; Choi, Chun Kit K; Bian, Liming

    2016-11-15

    Mussel adhesion has inspired the development of catechol-based adhesive polymers. However, conventional strategies require basic pH conditions and lead to the loss of adhesion. To solve the problem, we report the first attempt to use thiourea-functionalized polymers for preserving hydrogel adhesion. We believe that this simple thiourea-quinone coupling chemistry is instrumental to synthetic adhesive materials.

  8. The retinoblastoma protein: a master tumor suppressor acts as a link between cell cycle and cell adhesion

    Directory of Open Access Journals (Sweden)

    Engel BE

    2014-12-01

    Full Text Available Brienne E Engel,1 W Douglas Cress,1 Pedro G Santiago-Cardona2 1Molecular Oncology Program, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA; 2Department of Biochemistry, Ponce School of Medicine, Ponce, Puerto Rico, USA Abstract: RB1 was the first tumor suppressor gene discovered. Over 4 decades of work have revealed that the Rb protein (Rb is a master regulator of biological pathways influencing virtually every aspect of intrinsic cell fate including cell growth, cell-cycle checkpoints, differentiation, senescence, self-renewal, replication, genomic stability, and apoptosis. While these many processes may account for a significant portion of RB1's potency as a tumor suppressor, a small but growing stream of evidence suggests that RB1 also significantly influences how a cell interacts with its environment, including cell-to-cell and cell-to-extracellular matrix interactions. This review will highlight Rb’s role in the control of cell adhesion and how alterations in the adhesive properties of tumor cells may drive the deadly process of metastasis. Keywords: cadherin, integrin, Rb, cancer, aggressiveness, metastasis

  9. Inactivation of a fibronectin-binding TonB-dependent protein increases adhesion properties of Bacteroides fragilis.

    Science.gov (United States)

    Pauer, Heidi; Cavalcanti, Soraia N V; Teixeira, Felipe L; Santos-Filho, Joaquim; Vommaro, Rossiane C; Oliveira, Ana Carolina S C; Ferreira, Eliane O; Domingues, Regina R M C P

    2013-10-01

    Bacteroides fragilis is the Gram-negative strictly anaerobic bacterium most frequently isolated from clinical infections, including intra-abdominal abscess and bacteraemia. A number of factors can contribute to its virulence, including the expression of adhesins. Some of them are already characterized and can recognize and bind to extracellular matrix components, such as fibronectin. One of the molecules responsible for fibronectin-binding is an outer-membrane protein previously described by our group, which belongs to the TonB-dependent family. The aim of the present work was to characterize this protein. Initially, it was confirmed by fluorescence and electron microscopy that the fibronectin-binding molecules were located in the bacterial surface, but the distribution of these molecules on the surface was not uniform. To further evaluate the role of this protein, the gene bf1991, responsible for encoding this protein, was inactivated by a suicide vector and the mutant strains generated were used in several experiments to verify possible phenotypical alterations. In adherence assays with fibronectin immobilized on latex beads an increased adhesion was observed with the mutant strains compared with the wild-type strain. Western blot analysis in the mutant strain revealed the absence of the 120 kDa TonB-dependent outer-membrane protein and an alteration in the expression of an unknown 30 kDa protein. Killing assays using peritoneal macrophages were performed to evaluate the role of this protein as a virulence attribute and it was observed that the mutant strains were more efficiently internalized than the wild-type strains, with more internalization in the samples covered with fibronectin than in the samples not covered with it.

  10. Specific degradation of the mucus adhesion-promoting protein (MapA) of Lactobacillus reuteri to an antimicrobial peptide.

    Science.gov (United States)

    Bøhle, Liv Anette; Brede, Dag Anders; Diep, Dzung B; Holo, Helge; Nes, Ingolf F

    2010-11-01

    The intestinal flora of mammals contains lactic acid bacteria (LAB) that may provide positive health effects for the host. Such bacteria are referred to as probiotic bacteria. From a pig, we have isolated a Lactobacillus reuteri strain that produces an antimicrobial peptide (AMP). The peptide was purified and characterized, and it was unequivocally shown that the AMP was a well-defined degradation product obtained from the mucus adhesion-promoting protein (MapA); it was therefore termed AP48-MapA. This finding demonstrates how large proteins might inherit unexpected pleiotropic functions by conferring antimicrobial capacities on the producer. The MapA/AP48-MapA system is the first example where a large protein of an intestinal LAB is shown to give rise to such an AMP. It is also of particular interest that the protein that provides this AMP is associated with the binding of the bacterium producing it to the surface/lining of the gut. This finding gives us new perspective on how some probiotic bacteria may successfully compete in this environment and thereby contribute to a healthy microbiota.

  11. Polymer Composition and Substrate Influences on the Adhesive Bonding of a Biomimetic, Cross-Linking Polymer

    OpenAIRE

    Matos-Pérez, Cristina R.; White, James D.; Wilker, Jonathan J.

    2012-01-01

    Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have be...

  12. The adhesion G protein-coupled receptor G2 (ADGRG2/GPR64) constitutively activates SRE and NFκB and is involved in cell adhesion and migration

    DEFF Research Database (Denmark)

    Cornelia Peeters, Miriam; Fokkelman, Michiel; Boogaard, Bob

    2015-01-01

    intracellular signal transduction. Knockdown of ADGRG2 by siRNA in the highly motile breast cancer cell lines Hs578T and MDA-MB-231 resulted in a strong reduction in cell adhesion and subsequent cell migration which was associated with a selective reduction in RelB, an NFκB family member. It is concluded...

  13. Modification of gold surface by grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion.

    Science.gov (United States)

    Zhang, F; Kang, E T; Neoh, K G; Huang, W

    2001-01-01

    Gold surfaces were first treated in an alkanethiol solution to form self-assembled monolayers (SAMs). The thiolated Au surface was then subjected to Ar plasma pretreatment, followed by air exposure and UV-induced graft polymerization of poly(ethylene glycol) methacrylate (PEGMA) macromonomer. In comparison with the 3-mercaptopropionic acid-2-ethylhexyl ester (MPAEE) SAM, the (3-mercaptoproply)trimethoxysilane (MPTMS) SAM on Au exhibited higher stability under the conditions of Ar plasma pretreatment. The graft concentration of the PEGMA polymer on SAM-modified Au surface increased with increasing PEGMA macromonomer concentration and UV-graft polymerization time. The modified-Au surfaces were characterized by X-ray spectroscopy (XPS), atomic force microscopy (AFM), and water contact angle measurement. The Au surface with a high concentration of grafted PEGMA polymer could completely repel protein adsorption and platelet adhesion.

  14. Adhesion enhancement of biomimetic dry adhesives by nanoparticle in situ synthesis

    Science.gov (United States)

    Díaz Téllez, J. P.; Harirchian-Saei, S.; Li, Y.; Menon, C.

    2013-10-01

    A novel method to increase the adhesion strength of a gecko-inspired dry adhesive is presented. Gold nanoparticles are synthesized on the tips of the microfibrils of a polymeric dry adhesive to increase its Hamaker constant. Formation of the gold nanoparticles is qualitatively studied through a colour change in the originally transparent substance and quantitatively analysed using ultraviolet-visible spectrophotometry. A pull-off force test is employed to quantify the adhesion enhancement. Specifically, adhesion forces of samples with and without embedded gold nanoparticles are measured and compared. The experimental results indicate that an adhesion improvement of 135% can be achieved.

  15. Surface-tethered polymers to influence protein adsorption and microbial adhesion

    NARCIS (Netherlands)

    Norde, Willem

    2007-01-01

    In various applications it is desired that biological cells or protein molecules are immobilized at surfaces. Examples are enzymes or cells in bioreactors and biosensors, immuno-proteins in solid-state diagnostics and proteinaceous farmacons in drug delivery systems. In order to retain biological ac

  16. Lipopolysaccharide Binding Protein, Soluble-Intercellular Adhesion Molecule-1, Procalcitonin, and Protein C Activity and Clinical Outcome in Systemic Inflammatory Response Syndrome (SIRS or Sepsis Patients

    Directory of Open Access Journals (Sweden)

    Dewi Muliaty

    2009-04-01

    Full Text Available BACKGROUND: Biochemical markers may be used in diagnosis, prognostic and monitoring treatment and therapy for sepsis patients. In this study we used Lipopolysacharide Binding Protein (LBP, serum-Intercellular Adhesion Molecule-1 (ICAM-1, Procalcitonin (PCT and protein C activity. LBP is related to lipopolysachharide or gram-negative bacterial endotoxin which bound to LBP and induced inflammatory response. ICAM-1 is associated with endothelial dysfunction in response to systemic inflammatory and septic condition. PCT increased in bacterial infection and in severe systemic inflammatory. Role of Protein C is protecting the intravascular system to systemic inflammation, sepsis and the concomitant intravascular coagulopathy. The aim of this study was to examine the associations between levels of serum LBP, sICAM-1, PCT, and protein C activity with the clinical outcome of SIRS or sepsis patients. METHODS: We included 19 post surgery patients with SIRS criteria from intensive care unit (ICU and evaluated the level of LBP serum with Chemiliuminescent Enzyme Immunoassay (Diagnostic Product Co., ICAM-1 with ELISA (R&D System, PCT with immunochromatography (BRAHMS, protein C activity with chromogenic method (Dade Behring. We performed the samples serially at the first admission of patients and after 72 hours. Data were analysed by non-parametric with Wilcoxon test and Mann-Whitney test. Correlation study between biomarkers calculated by Kendall’s tau and Spearman’s rho. RESULTS: Of 19 patients, 9 (47,4% died and 10 (52,6% surviving. The level of LBP serum decreased after 72 hours in surviving-sepsis patients, and increased in nonsurviving sepsis patients with significant different levels at 72 hours examination (p0.05. In all patients were found high level of PCT serum since the first admission examination, decreasing levels were occurred significantly in surviving patients after 72 hours (p0.05 both in surviving and non-surviving patients. CONCLUSIONS

  17. Molecular cloning and characterization of a surface-localized adhesion protein in Mycoplasma bovis Hubei-1 strain.

    Directory of Open Access Journals (Sweden)

    Xiaohui Zou

    Full Text Available Mycoplasma bovis (M. bovis is an important pathogen that causes various bovine diseases, such as mastitis in cows and pneumonia in calves. The surface proteins are generally thought to play a central role in the pathogenesis of this organism. We screened the entire genome of M. bovis Hubei-1 and discovered a gene named vpmaX that encodes the 25 kDa variable surface lipoprotein A (VpmaX. Sequence analysis revealed that VpmaX contains several repetitive units and a typical bacterial lipoprotein signal sequence. The vpmaX gene was cloned and expressed in E. coli to obtain recombinant VpmaX (rVpmaX. Western blot analysis using a rabbit antibody against rVpmaX demonstrated that VpmaX is a membrane protein. Immunostaining visualized via confocal laser scanning microscopy showed that rVpmaX was able to adhere to embryonic bovine lung cells (EBL, and this was also confirmed by a sandwich ELISA. In summary, a surface-localized adhesion protein was identified in M. bovis Hubei-1.

  18. Water Resistance of Soy Protein Based Adhesives Enhanced by Na-MMT%钠基蒙脱土增强豆胶的耐水性研究

    Institute of Scientific and Technical Information of China (English)

    桂成胜; 刘小青; 吴(頔); 王古月; 朱锦

    2012-01-01

    The adhesion strength and water resistance of soy protein based adhesives were enhanced by adding Na-montmorillonite(Na-MMT). The adhesion strength and water resistance were the highest when 1 wt% Na-MMT was added. The adhesion strength and type- Ⅱ wet strength of the poplar plywood were improved by 20.5% and 18.8% respectively. The water resistance mechanism of Na-MMT enhanced soy protein based adhesion was analyzed by using XRD, TEM, FTIR and contact angle.%钠基蒙脱土(Na-MMT)的加入,提高了大豆蛋白胶黏剂的预压性能、粘接强度和耐水性,当Na-MMT的加入量为大豆分离蛋白的1 wt%时,增强效果最好,可以使杨木胶合板的干强度和Ⅱ类湿强度分别提高20.5%和18.8%;利用XRD、TEM、FUR、接触角等分析方法研究了Na-MMT增强豆胶耐水性的机理.

  19. Hydrogen-Rich Medium Attenuated Lipopolysaccharide-Induced Monocyte-Endothelial Cell Adhesion and Vascular Endothelial Permeability via Rho-Associated Coiled-Coil Protein Kinase.

    Science.gov (United States)

    Xie, Keliang; Wang, Weina; Chen, Hongguang; Han, Huanzhi; Liu, Daquan; Wang, Guolin; Yu, Yonghao

    2015-07-01

    Sepsis is the leading cause of death in critically ill patients. In recent years, molecular hydrogen, as an effective free radical scavenger, has been shown a selective antioxidant and anti-inflammatory effect, and it is beneficial in the treatment of sepsis. Rho-associated coiled-coil protein kinase (ROCK) participates in junction between normal cells, and regulates vascular endothelial permeability. In this study, we used lipopolysaccharide to stimulate vascular endothelial cells and explored the effects of hydrogen-rich medium on the regulation of adhesion of monocytes to endothelial cells and vascular endothelial permeability. We found that hydrogen-rich medium could inhibit adhesion of monocytes to endothelial cells and decrease levels of adhesion molecules, whereas the levels of transepithelial/endothelial electrical resistance values and the expression of vascular endothelial cadherin were increased after hydrogen-rich medium treatment. Moreover, hydrogen-rich medium could lessen the expression of ROCK, as a similar effect of its inhibitor Y-27632. In addition, hydrogen-rich medium could also inhibit adhesion of polymorphonuclear neutrophils to endothelial cells. In conclusion, hydrogen-rich medium could regulate adhesion of monocytes/polymorphonuclear neutrophils to endothelial cells and vascular endothelial permeability, and this effect might be related to the decreased expression of ROCK protein.

  20. Expression of neural cell adhesion molecules and neurofilament protein isoforms in Ewing's sarcoma of bone and soft tissue sarcomas of other than rhabdomyosarcoma

    NARCIS (Netherlands)

    Molenaar, W.M.; Muntinghe, F.L.H.

    1999-01-01

    In a previous study, it was shown that rhabdomyosarcomas widely express "neural" markers, such as neural cell adhesion molecules (N-CAM) and neurofilament protein isoforms, In the current study, a series of Ewing's sarcomas of bone and soft tissue sarcomas other than rhabdomyosarcoma was probed for

  1. Comparison of adhesive properties of water- and phosphate-buffer-washed cottonseed meals with cottonseed protein isolate on maple and poplar veneers

    Science.gov (United States)

    Water- and phosphate buffer (35 mM Na2HPO4/NaH2PO4, pH 7.5)-washed cottonseed meals (abbreviated as WCM and BCM, respectively) could be low-cost and environmentally friendly protein-based adhesives as their preparation does not involve corrosive alkali and acid solutions that are needed for cottonse...

  2. Extraction of Jatropha curcas proteins and application in polyketone-based wood adhesives

    NARCIS (Netherlands)

    Hamarneh, A. I.; Heeres, H. J.; Broekhuis, A. A.; Picchioni, F.

    2010-01-01

    Jatropha proteins were successfully extracted from the corresponding seeds using the principle of isoelectric precipitation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), elemental analysis and Fourier transform infrared spectroscopy (FTIR) were used to analyze the obtained p

  3. Laminin-511: a multi-functional adhesion protein regulating cell migration, tumor invasion and metastasis.

    Science.gov (United States)

    Pouliot, Normand; Kusuma, Nicole

    2013-01-01

    Laminins are major constituents of basement membranes. At least 16 isoforms have now been described, each with distinct spatio-temporal expression patterns and functions. The laminin-511 heterotrimer (α5β1γ1) is one of the more recent isoforms to be identified and a potent adhesive and pro-migratory substrate for a variety of normal and tumor cell lines in vitro. As our understanding of its precise function in normal tissues and in pathologies is rapidly unraveling, current evidence suggests an important regulatory role in cancer. This review describes published data on laminin-511 expression in several malignancies and experimental evidence from both in vitro and in vivo studies supporting its functional role during tumor progression. A particular emphasis is put on more recent studies from our laboratory and that of others indicating that laminin-511 contributes to tumor dissemination and metastasis in advanced breast carcinomas and other tumor types. Collectively, the experimental evidence suggests that high expression of laminin-511 has prognostic significance and that targeting tumor-laminin-511 interactions may have therapeutic potential in advanced cancer patients.

  4. Adsorption and adhesion of common serum proteins to nanotextured gallium nitride.

    Science.gov (United States)

    Bain, Lauren E; Hoffmann, Marc P; Bryan, Isaac; Collazo, Ramón; Ivanisevic, Albena

    2015-02-14

    As the broader effort towards device and material miniaturization progresses in all fields, it becomes increasingly important to understand the implications of working with functional structures that approach the size scale of molecules, particularly when considering biological systems. It is well known that thin films and nanostructures feature different optical, electrical, and mechanical properties from their bulk composites; however, interactions taking place at the interface between nanomaterials and their surroundings are less understood. Here, we explore interactions between common serum proteins - serum albumin, fibrinogen, and immunoglobulin G - and a nanotextured gallium nitride surface. Atomic force microscopy with a carboxyl-terminated colloid tip is used to probe the 'activity' of proteins adsorbed onto the surface, including both the accessibility of the terminal amine to the tip as well as the potential for protein extension. By evaluating the frequency of tip-protein interactions, we can establish differences in protein behaviour on the basis of both the surface roughness as well as morphology, providing an assessment of the role of surface texture in dictating protein-surface interactions. Unidirectional surface features - either the half-unit cell steppes of as-grown GaN or those produced by mechanical polishing - appear to promote protein accessibility, with a higher frequency of protein extension events taking place on these surfaces when compared with less ordered surface features. Development of a full understanding of the factors influencing surface-biomolecule interactions can pave the way for specific surface modification to tailor the bio-material interface, offering a new path for device optimization.

  5. Atmospheric pressure plasma polymers for tuned QCM detection of protein adhesion.

    Science.gov (United States)

    Rusu, G B; Asandulesa, M; Topala, I; Pohoata, V; Dumitrascu, N; Barboiu, M

    2014-03-15

    Our efforts have been concentrated in preparing plasma polymeric thin layers at atmospheric pressure grown on Quartz Crystal Microbalance-QCM electrodes for which the non-specific absorption of proteins can be efficiently modulated, tuned and used for QCM biosensing and quantification. Plasma polymerization reaction at atmospheric pressure has been used as a simple and viable method for the preparation of QCM bioactive surfaces, featuring variable protein binding properties. Polyethyleneglycol (ppEG), polystyrene (ppST) and poly(ethyleneglycol-styrene) (ppST-EG) thin-layers have been grown on QCM electrodes. These layers were characterized by Atomic Force Microscopy (AFM), Contact angle measurements, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS). The plasma ppST QCM electrodes present a higher adsorption of Concanavalin A (ConA) and Bovine Serum Albumin (BSA) proteins when compared with the commercial coated polystyrene (ppST) ones. The minimum adsorption was found for ppEG, surface, known by their protein anti-fouling properties. The amount of adsorbed proteins can be tuned by the introduction of PEG precursors in the plasma discharge during the preparation of ppST polymers. © 2013 Elsevier B.V. All rights reserved.

  6. Silk-fibronectin protein alloy fibres support cell adhesion and viability as a high strength, matrix fibre analogue

    Science.gov (United States)

    Jacobsen, Matthew M.; Li, David; Gyune Rim, Nae; Backman, Daniel; Smith, Michael L.; Wong, Joyce Y.

    2017-04-01

    Silk is a natural polymer with broad utility in biomedical applications because it exhibits general biocompatibility and high tensile material properties. While mechanical integrity is important for most biomaterial applications, proper function and integration also requires biomaterial incorporation into complex surrounding tissues for many physiologically relevant processes such as wound healing. In this study, we spin silk fibroin into a protein alloy fibre with whole fibronectin using wet spinning approaches in order to synergize their respective strength and cell interaction capabilities. Results demonstrate that silk fibroin alone is a poor adhesive surface for fibroblasts, endothelial cells, and vascular smooth muscle cells in the absence of serum. However, significantly improved cell attachment is observed to silk-fibronectin alloy fibres without serum present while not compromising the fibres’ mechanical integrity. Additionally, cell viability is improved up to six fold on alloy fibres when serum is present while migration and spreading generally increase as well. These findings demonstrate the utility of composite protein alloys as inexpensive and effective means to create durable, biologically active biomaterials.

  7. Laser- and UV-assisted modification of polystyrene surfaces for control of protein adsorption and cell adhesion

    Science.gov (United States)

    Pfleging, Wilhelm; Torge, Maika; Bruns, Michael; Trouillet, Vanessa; Welle, Alexander; Wilson, Sandra

    2009-03-01

    An appropriate choice of laser and process parameters enables new approaches for the fabrication of polymeric lab-on-chip devices with integrated functionalities. We will present our current research results in laser-assisted modification of polystyrene (PS) with respect to the fabrication of polymer devices for cell culture applications. For this purpose laser micro-patterning of PS and subsequent surface functionalization was investigated as function of laser and process parameters. A high power ArF-excimer laser radiation source with a pulse length of 19 ns as well as a high repetition ArF-excimer laser source with a pulse length of 5 ns were used in order to study the influence of laser pulse length on laser-induced surface oxidation. The change in surface chemistry was characterized by X-ray photoelectron spectroscopy and contact angle measurements. The difference between laser-assisted modification versus UV-lamp assisted modification was investigated. A photolytic activation of specific areas of the polymer surface and subsequent oxidization in oxygen or ambient air leads to a chemically modified polymer surface bearing carboxylic acid groups well-suited for controlled competitive protein adsorption or protein immobilization. Finally, distinct areas for cell growth and adhesion are obtained.

  8. A novel COX-independent mechanism of sulindac sulfide involves cleavage of epithelial cell adhesion molecule protein.

    Science.gov (United States)

    Liggett, Jason L; Min, Kyung-Won; Smolensky, Dmitriy; Baek, Seung Joon

    2014-08-01

    Non-steroidal anti-inflammatory drugs (NSAIDs) are extensively used over the counter to treat headaches and inflammation as well as clinically to prevent cancer among high-risk groups. The inhibition of cyclooxygenase (COX) activity by NSAIDs plays a role in their anti-tumorigenic properties. NSAIDs also have COX-independent activity which is not fully understood. In this study, we report a novel COX-independent mechanism of sulindac sulfide (SS), which facilitates a previously uncharacterized cleavage of epithelial cell adhesion molecule (EpCAM) protein. EpCAM is a type I transmembrane glycoprotein that has been implemented as an over-expressed oncogene in many cancers including colon, breast, pancreas, and prostate. We found EpCAM to be down-regulated by SS in a manner that is independent of COX activity, transcription regulation, de novo protein synthesis, and proteasomal degradation pathway. Our findings clearly demonstrate that SS drives cleavage of the extracellular portion of EpCAM near the N-terminus. This SS driven cleavage is blocked by a deleting amino acids 55-81 as well as simply mutating arginine residues at positions 80 and 81 to alanine of EpCAM. Proteolysis of EpCAM by SS may provide a novel mechanism by which NSAIDs affect anti-tumorigenesis at the post-translational level.

  9. Cyclic di-GMP contributes to adaption and virulence of Bacillus thuringiensis through a riboswitch-regulated collagen adhesion protein.

    Science.gov (United States)

    Tang, Qing; Yin, Kang; Qian, Hongliang; Zhao, Youwen; Wang, Wen; Chou, Shan-Ho; Fu, Yang; He, Jin

    2016-07-06

    Cyclic di-GMP is a ubiquitous second messenger that regulates diverse cellular processes in bacteria by binding to various protein or riboswitch effectors. In Bacillus thuringiensis BMB171, a c-di-GMP riboswitch termed Bc2 RNA resides in the 5'-untranslated region (5'-UTR) of an mRNA that encodes a collagen adhesion protein (Cap). The expression of cap was strongly repressed in parent strain BMB171 because of the presence of Bc2 RNA but was significantly promoted in the Bc2 RNA markerless deletion mutant. Bc2 RNA acts as a genetic "on" switch, which forms an anti-terminator structure to promote cap read-through transcription upon c-di-GMP binding. As a result, cap transcription was de-repressed under high c-di-GMP levels. Therefore, Bc2 RNA regulates cap expression using a repression/de-repression model. Bc2 RNA-regulated Cap was also found to be tightly associated with motility, aggregation, exopolysaccharide secretion, biofilm formation, and virulence of B. thuringiensis BMB171 against its host insect Helicoverpa armigera.

  10. ADHESION-INDUCE PROTEIN TYROSINE PHOSPHORY-LATION IS ASSOCIATED WITH INVASIVE AND METASTATIC POTENTIALS IN B16-BL6 MELANOMA CELLS

    Institute of Scientific and Technical Information of China (English)

    Yan Chunhong; Han Rui

    1998-01-01

    Objective: The interaction of cancer cell with extracellular matrix (ECM) happens as an earlier and specific event in the invasive and metastatic cascade. To explore the key element(s) in cancer metastasis and observe the cell-ECM interaction and its role. Methods:To interrupt the cell-ECM interaction by suppression of adhesion-induced protein tyrosine phosphorylation with protein tyrosine kinase inhibitor genistein in B16-B16mouse melanoma cells. Results: When B16-BL6 cells attached to Matrigel, a solubilized basement membrane preparation from EHS sarcoma, a 125 kDa protein increased its phosphotyrosine content dramatically. In contrast, when the cells were pretreated with 20μM or 30μM genistein for 3 days, it was revealed a less increase in the phosphotyrosine content of this 125 kDa protein inresponse to cell attachment to ECM was revealed with immunoblot analysis. Accompanied by the lower level of adhesion-induced protein tyrosine phosphorylation the genistein-treated cells exhibited a decrease in their capabilities of adhesion to Matrigel and invasion through reconstituted basement membrane. The potentials of and forming lung metastatic nodules were also shown to be decreased dramatically in these genistein-treated cells.Conclusion: It was suggested that protein tyrosine phosphorylation in cell-ECM interaction might be associated with invasive and metastatic potentials in cancer cells.

  11. Endothelial cell adhesion and growth within a bioassay chamber using microstamped ECM proteins

    Science.gov (United States)

    Rubenstein, David A.; Frame, Mary D.

    2011-06-01

    Our goal was to evaluate microvascular endothelial cell growth on microstamped patterns of extracellular matrix proteins (ECM). A combination of photo- and soft-lithography was used to make features ˜100 μm deep and 150μm wide. Polydimethylsiloxane imprints of features produced positive molds used to stamp collagen I, IV, laminin and fibronectin onto cleaned hydrophilic or hydrophobic glass coverslips. Human dermal microvascular endothelial cells were seeded at an initial density of 800 cells cm-2, and cultured for three days. Explanted murine aortas, serving as an initial source for autologous endothelial cells, were perfused at 240 μL min-1 for 1 day. Cell morphology was also quantified on both the non-patterned glass and within the microstamped patterns. Viability was high (>90%) on all microstamped proteins, regardless of glass hydrophobicity. Viability was reduced on bare hydrophobic glass. Cell density was 4 or 8 fold higher on microstamped ECM proteins compared with hydrophilic or hydrophobic glass, respectively. Confluence was approached more rapidly on microstamped proteins. Thus, rapid concentrated growth of endothelial cells was markedly enhanced within microstamped ECM patterns on hydrophilic and hydrophobic glass.

  12. Interleukin-2 induces beta2-integrin-dependent signal transduction involving the focal adhesion kinase-related protein B (fakB)

    DEFF Research Database (Denmark)

    Brockdorff, J; Kanner, S B; Nielsen, M;

    1998-01-01

    experiments indicate that the IL-2-induced 125-kDa phosphotyrosine protein is the focal adhesion kinase-related protein B (fakB). Thus, IL-2 induces strong tyrosine phosphorylation of fakB in beta2-integrin-positive but not in beta2-integrin-negative T cells, and CD18 mAb selectively blocks IL-2-induced fakB......-tyrosine phosphorylation in beta2-integrin-positive T cells. In parallel experiments, IL-2 does not induce or augment tyrosine phosphorylation of p125(FAK). In conclusion, our data indicate that IL-2 induces beta2-integrin-dependent signal transduction events involving the tyrosine kinase substrate fakB....... and a leukocyte adhesion deficiency (LAD) patient. We show that IL-2 induces tyrosine phosphorylation of a 125-kDa protein and homotypic adhesion in beta2 integrin (CD18)-positive but not in beta2-integrin-negative T cells. EDTA, an inhibitor of integrin adhesion, blocks IL-2-induced tyrosine phosphorylation...

  13. Structure and function of ameloblastin as an extracellular matrix protein: adhesion, calcium binding, and CD63 interaction in human and mouse.

    Science.gov (United States)

    Zhang, Xu; Diekwisch, Thomas G H; Luan, Xianghong

    2011-12-01

    The functional significance of extracellular matrix proteins in the life of vertebrates is underscored by a high level of sequence variability in tandem with a substantial degree of conservation in terms of cell-cell and cell-matrix adhesion interactions. Many extracellular matrix proteins feature multiple adhesion domains for successful attachment to substrates, such as integrin, CD63, and heparin. Here we have used homology and ab initio modeling algorithms to compare mouse ameloblastin (mAMBN) and human ameloblastin (hABMN) isoforms and to analyze their potential for cell adhesion and interaction with other matrix molecules as well as calcium binding. Sequence comparison between mAMBN and hAMBN revealed a 26-amino-acid deletion in mAMBN, corresponding to a helix-loop-helix frameshift. The human AMBN domain (174Q-201G), homologous to the mAMBN 157E-178I helix-loop-helix region, formed a helix-loop motif with an extended loop, suggesting a higher degree of flexibility of hAMBN compared with mAMBN, as confirmed by molecular dynamics simulation. Heparin-binding domains, CD63-interaction domains, and calcium-binding sites in both hAMBN and mAMBN support the concept of AMBN as an extracellular matrix protein. The high level of conservation between AMBN functional domains related to adhesion and differentiation was remarkable when compared with only 61% amino acid sequence homology.

  14. A fucan from the brown seaweed Spatoglossum schröederi inhibits Chinese hamster ovary cell adhesion to several extracellular matrix proteins

    Directory of Open Access Journals (Sweden)

    H.A.O. Rocha

    2001-05-01

    Full Text Available Fucans, a family of sulfated polysaccharides present in brown seaweed, have several biological activities. Their use as drugs would offer the advantage of no potential risk of contamination with viruses or particles such as prions. A fucan prepared from Spatoglossum schröederi was tested as a possible inhibitor of cell-matrix interactions using wild-type Chinese hamster ovary cells (CHO-K1 and the mutant type deficient in xylosyltransferase (CHO-745. The effect of this polymer on adhesion properties with specific extracellular matrix components was studied using several matrix proteins as substrates for cell attachment. Treatment with the polymer inhibited the adhesion of fibronectin to both CHO-K1 (2 x 10(5(and CHO-745 (2 x 10(5 and 5 x 10(5 cells. No effect was detected with laminin, using the two cell types. On the other hand, adhesion to vitronectin was inhibited in CHO-K1 cells and adhesion to type I collagen was inhibited in CHO-745 cells. In spite of this inhibition, the fucan did not affect either cell proliferation or cell cycle. These results demonstrate that this polymer is a new anti-adhesive compound with potential pharmacological applications.

  15. A fucan from the brown seaweed Spatoglossum schröederi inhibits Chinese hamster ovary cell adhesion to several extracellular matrix proteins.

    Science.gov (United States)

    Rocha, H A; Franco, C R; Trindade, E S; Carvalho, L C; Veiga, S S; Leite, E L; Dietrich, C P; Nader, H B

    2001-05-01

    Fucans, a family of sulfated polysaccharides present in brown seaweed, have several biological activities. Their use as drugs would offer the advantage of no potential risk of contamination with viruses or particles such as prions. A fucan prepared from Spatoglossum schröederi was tested as a possible inhibitor of cell-matrix interactions using wild-type Chinese hamster ovary cells (CHO-K1) and the mutant type deficient in xylosyltransferase (CHO-745). The effect of this polymer on adhesion properties with specific extracellular matrix components was studied using several matrix proteins as substrates for cell attachment. Treatment with the polymer inhibited the adhesion of fibronectin to both CHO-K1 (2 x 10(5)) and CHO-745 (2 x 10(5) and 5 x 10(5)) cells. No effect was detected with laminin, using the two cell types. On the other hand, adhesion to vitronectin was inhibited in CHO-K1 cells and adhesion to type I collagen was inhibited in CHO-745 cells. In spite of this inhibition, the fucan did not affect either cell proliferation or cell cycle. These results demonstrate that this polymer is a new anti-adhesive compound with potential pharmacological applications.

  16. The membrane protein melanoma cell adhesion molecule (MCAM) is a novel tumor marker that stimulates tumorigenesis in hepatocellular carcinoma.

    Science.gov (United States)

    Wang, J; Tang, X; Weng, W; Qiao, Y; Lin, J; Liu, W; Liu, R; Ma, L; Yu, W; Yu, Y; Pan, Q; Sun, F

    2015-11-19

    Yes-associated protein (YAP) is overexpressed and has an oncogenic role in hepatocellular carcinoma (HCC). However, whether membrane protein can serve not only as a tumor marker that reflects YAP function but also as a therapeutic target that stimulates tumorigenesis in HCC remains unknown. Here we report that the membrane protein melanoma cell adhesion molecule (MCAM) was under positive regulation by YAP and was highly elevated in HCC cells. Within the MCAM promoter, we found the presence of a cAMP Response Element (CRE; -32 to -25 nt), which is conserved among species and is essential for YAP- and CREB-dependent regulation. Moreover, the interaction between CREB and YAP at the CRE site was dependent on PTPIY-WW domain interactions. However, MCAM expression was low and could not be regulated by YAP in breast and colon cancer cells because of the low levels of the acetyltransferase p300. In HCC cells, high levels of p300 facilitated the binding of YAP to the MCAM promoter, which in turn enhanced histone acetylation and polymerase II recruitment through the dissociation of the deacetylase Sirt1. These results suggest that MCAM is an HCC-specific target of YAP. In clinical serum samples, we found that the serum levels of MCAM were highly elevated in patients with HCC compared with healthy controls and with patients with cirrhosis, hepatitis, colon cancer and breast cancer. MCAM levels were shown to be a slightly better indicator than serum alpha-fetoprotein for predicting HCC. We further demonstrated that MCAM is essential for the survival and transformation of HCC. Mechanistically, MCAM induced translation initiation and the transcriptional activities of c-Jun/c-Fos. In addition, AKT activation had an essential role in the MCAM-promoted binding of eukaryotic initiation factor 4E to c-Jun/c-Fos mRNA. In conclusion, we demonstrated that MCAM may be a potential tumor marker and therapeutic target for the diagnosis and treatment of HCC.

  17. Influence of poly(ethylene oxide)-based copolymer on protein adsorption and bacterial adhesion on stainless steel: modulation by surface hydrophobicity.

    Science.gov (United States)

    Yang, Yi; Rouxhet, Paul G; Chudziak, Dorota; Telegdi, Judit; Dupont-Gillain, Christine C

    2014-06-01

    The aim of the present work is to study the adhesion of Pseudomonas NCIMB 2021, a typical aerobic marine microorganism, on stainless steel (SS) substrate. More particularly, the potential effect on adhesion of adsorbed poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymer is investigated. Bacterial attachment experiments were carried out using a modified parallel plate flow chamber, allowing different surface treatments to be compared in a single experiment. The amount of adhering bacteria was determined via DAPI staining and fluorescence microscopy. X-ray photoelectron spectroscopy (XPS) was used to characterize the surface chemical composition of SS and hydrophobized SS before and after PEO-PPO-PEO adsorption. The adsorption of bovine serum albumin (BSA), a model protein, was investigated to test the resistance of PEO-PPO-PEO layers to protein adsorption. The results show that BSA adsorption and Pseudomonas 2021 adhesion are significantly reduced on hydrophobized SS conditioned with PEO-PPO-PEO. Although PEO-PPO-PEO is also found to adsorb on SS, it does not prevent BSA adsorption nor bacterial adhesion, which is attributed to different PEO-PPO-PEO adlayer structures on hydrophobic and hydrophilic surfaces. The obtained results open the way to a new strategy to reduce biofouling on metal oxide surfaces using PEO-PPO-PEO triblock copolymer.

  18. Implication of sortase-dependent proteins of Streptococcus thermophilus in adhesion to human intestinal epithelial cell lines and bile salt tolerance.

    Science.gov (United States)

    Kebouchi, Mounira; Galia, Wessam; Genay, Magali; Soligot, Claire; Lecomte, Xavier; Awussi, Ahoefa Ablavi; Perrin, Clarisse; Roux, Emeline; Dary-Mourot, Annie; Le Roux, Yves

    2016-04-01

    Streptococcus thermophilus (ST) is a lactic acid bacterium widely used in dairy industry and displays several properties which could be beneficial for host. The objective of this study was to investigate, in vitro, the implication of sortase A (SrtA) and sortase-dependent proteins (SDPs) in the adhesion of ST LMD-9 strain to intestinal epithelial cells (IECs) and resistance to bile salt mixture (BSM; taurocholoate, deoxycholate, and cholate). The effect of mutations in prtS (protease), mucBP (MUCin-Binding Protein), and srtA genes in ST LMD-9 in these mechanisms were examined. The HT29-MTX, HT29-CL.16E, and Caco-2 TC7 cell lines were used. HT29-MTX and HT29-CL.16E cells express different mucins found in the gastro intestinal tract; whereas, Caco-2 TC7 express cell surface proteins found in the small intestine. All mutants showed different adhesion profiles depending on cell lines. The mutation in genes srtA and mucBP leads to a significant decrease in LMD-9 adhesion capacity to Caco-2 TC7 cells. A mutation in mucBP gene has also shown a significant decrease in LMD-9 adhesion capacity to HT29-CL.16E cells. However, no difference was observed using HT29-MTX cells. Furthermore, ST LMD-9 and srtA mutant were resistant to BSM up to 3 mM. Contrariwise, no viable bacteria were detected for prtS and mucBP mutants at this concentration. Two conclusions could be drawn. First, SDPs could be involved in the LMD-9 adhesion depending on the cell lines indicating the importance of eukaryotic-cell surface components in adherence. Second, SDPs could contribute to resistance to bile salts probably by maintaining the cell membrane integrity.

  19. Adhesion protein ApfA of Actinobacillus pleuropneumoniae is required for pathogenesis and is a potential target for vaccine development.

    Science.gov (United States)

    Zhou, Yang; Li, Lu; Chen, Zhaohui; Yuan, Hong; Chen, Huanchun; Zhou, Rui

    2013-02-01

    Actinobacillus pleuropneumoniae is the etiologic agent of porcine pleuropneumonia, which causes serious economic losses in the pig farming industry worldwide. Due to a lack of knowledge of its virulence factors and a lack of effective vaccines able to confer cross-serotype protection, it is difficult to place this disease under control. By analyzing its genome sequences, we found that type IV fimbrial subunit protein ApfA is highly conserved among different serotypes of A. pleuropneumoniae. Our study shows that ApfA is an adhesin since its expression was greatly upregulated (135-fold) upon contact with host cells, while its deletion mutant attenuated its capability of adhesion. The inactivation of apfA dramatically reduced the ability of A. pleuropneumoniae to colonize mouse lung, suggesting that apfA is a virulence factor. Purified recombinant ApfA elicited an elevated humoral immune response and conferred robust protection against challenges with A. pleuropneumoniae serovar 1 strain 4074 and serovar 7 strain WF83 in mice. Importantly, the anti-ApfA serum conferred significant protection against both serovar 1 and serovar 7 in mice. These studies indicate that ApfA promotes virulence through attachment to host cells, and its immunogenicity renders it a promising novel subunit vaccine candidate against infection with A. pleuropneumoniae.

  20. A family of ROP proteins that suppresses actin dynamics, and is essential for polarized growth and cell adhesion.

    Science.gov (United States)

    Burkart, Graham M; Baskin, Tobias I; Bezanilla, Magdalena

    2015-07-15

    In plants, the ROP family of small GTPases has been implicated in the polarized growth of tip-growing cells, such as root hairs and pollen tubes; however, most of the data derive from overexpressing ROP genes or constitutively active and dominant-negative isoforms, whereas confirmation by using loss-of-function studies has generally been lacking. Here, in the model moss Physcomitrella patens, we study ROP signaling during tip growth by using a loss-of-function approach based on RNA interference (RNAi) to silence the entire moss ROP family. We find that plants with reduced expression of ROP genes, in addition to failing to initiate tip growth, have perturbed cell wall staining, reduced cell adhesion and have increased actin-filament dynamics. Although plants subjected to RNAi against the ROP family also have reduced microtubule dynamics, this reduction is not specific to loss of ROP genes, as it occurs when actin function is compromised chemically or genetically. Our data suggest that ROP proteins polarize the actin cytoskeleton by suppressing actin-filament dynamics, leading to an increase in actin filaments at the site of polarized secretion.

  1. Focal Adhesion Kinase-mediated Phosphorylation of Beclin1 Protein Suppresses Cardiomyocyte Autophagy and Initiates Hypertrophic Growth*♦

    Science.gov (United States)

    Cheng, Zhaokang; Zhu, Qiang; Dee, Rachel; Opheim, Zachary; Mack, Christopher P.; Cyr, Douglas M.; Taylor, Joan M.

    2017-01-01

    Autophagy is an evolutionarily conserved intracellular degradation/recycling system that is essential for cellular homeostasis but is dysregulated in a number of diseases, including myocardial hypertrophy. Although it is clear that limiting or accelerating autophagic flux can result in pathological cardiac remodeling, the physiological signaling pathways that fine-tune cardiac autophagy are poorly understood. Herein, we demonstrated that stimulation of cardiomyocytes with phenylephrine (PE), a well known hypertrophic agonist, suppresses autophagy and that activation of focal adhesion kinase (FAK) is necessary for PE-stimulated autophagy suppression and subsequent initiation of hypertrophic growth. Mechanistically, we showed that FAK phosphorylates Beclin1, a core autophagy protein, on Tyr-233 and that this post-translational modification limits Beclin1 association with Atg14L and reduces Beclin1-dependent autophagosome formation. Remarkably, although ectopic expression of wild-type Beclin1 promoted cardiomyocyte atrophy, expression of a Y233E phosphomimetic variant of Beclin1 failed to affect cardiomyocyte size. Moreover, genetic depletion of Beclin1 attenuated PE-mediated/FAK-dependent initiation of myocyte hypertrophy in vivo. Collectively, these findings identify FAK as a novel negative regulator of Beclin1-mediated autophagy and indicate that this pathway can facilitate the promotion of compensatory hypertrophic growth. This novel mechanism to limit Beclin1 activity has important implications for treating a variety of pathologies associated with altered autophagic flux. PMID:27994061

  2. Heat shock protein 90β stabilizes focal adhesion kinase and enhances cell migration and invasion in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Xiangyang [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi 330006 (China); State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Wang, Yao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Liu, Chengmei [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Lu, Quqin [Department of Biostatistics and Epidemiology, School of Public Health, Nanchang University, Nanchang, Jiangxi 330006 (China); Liu, Tao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Chen, Guoan [Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006 (China); Rao, Hai [Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, TX 78229 (United States); Luo, Shiwen, E-mail: shiwenluo@ncu.edu.cn [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China)

    2014-08-01

    Focal adhesion kinase (FAK) acts as a regulator of cellular signaling and may promote cell spreading, motility, invasion and survival in malignancy. Elevated expression and activity of FAK frequently correlate with tumor cell metastasis and poor prognosis in breast cancer. However, the mechanisms by which the turnover of FAK is regulated remain elusive. Here we report that heat shock protein 90β (HSP90β) interacts with FAK and the middle domain (amino acids 233–620) of HSP90β is mainly responsible for this interaction. Furthermore, we found that HSP90β regulates FAK stability since HSP90β inhibitor 17-AAG triggers FAK ubiquitylation and subsequent proteasome-dependent degradation. Moreover, disrupted FAK-HSP90β interaction induced by 17-AAG contributes to attenuation of tumor cell growth, migration, and invasion. Together, our results reveal how HSP90β regulates FAK stability and identifies a potential therapeutic strategy to breast cancer. - Highlights: • HSP90β protects FAK from degradation by the ubiquitin-proteasome pathway. • Inhibition of HSP90β or FAK attenuates tumorigenesis of breast cancer cells. • Genetic repression of HSP90β or FAK inhibits tumor cell migration and proliferation. • Inhibition of HSP90β or FAK interferes cell invasion and cytoskeleton.

  3. Proteins Play Important Role in Intercellular Adhesion Affecting on Fruit Textural Quality

    DEFF Research Database (Denmark)

    Bahadur Adhikari, Khem; Shomer, Ilan

    2012-01-01

    strengthening was exempli ed in Medjoul date (Phoenix dactylifera L.) fruit, as a model. Fruit mesocarp sensitively responded to culture environment which was assayed in vitro at pH 3.5( pKa) in presence of organic acid molecules. The max penetration force, as a measure of ICA strength, of p......H 3.5 (incubated mesocarp (~10.5 N) was signi cantly higher than that of pH 6.5 (> pKa) incubated fruits (~2 N). The protein bands at ~29 kDa, ~75 kDa, ~32 kDa and 87 kDa were exclusively or prominently found in ICA strengthened fruits (pH 3.5

  4. Characterization and significance of adhesion and junction-related proteins in mouse ovarian follicles.

    Science.gov (United States)

    Mora, Jocelyn M; Fenwick, Mark A; Castle, Laura; Baithun, Marianne; Ryder, Timothy A; Mobberley, Margaret; Carzaniga, Raffaella; Franks, Stephen; Hardy, Kate

    2012-05-01

    In the ovary, initiation of follicle growth is marked by cuboidalization of flattened granulosa cells (GCs). The regulation and cell biology of this shape change remains poorly understood. We propose that characterization of intercellular junctions and associated proteins is key to identifying as yet unknown regulators of this important transition. As GCs are conventionally described as epithelial cells, this study used mouse ovaries and isolated follicles to investigate epithelial junctional complexes (tight junctions [TJ], adherens junctions [AJ], and desmosomes) and associated molecules, as well as classic epithelial markers, by quantitative PCR and immunofluorescence. These junctions were further characterized using ultrastructural, calcium depletion and biotin tracer studies. Junctions observed by transmission electron microscopy between GCs and between GCs and oocyte were identified as AJs by expression of N-cadherin and nectin 2 and by the lack of TJ and desmosome-associated proteins. Follicles were also permeable to biotin, confirming a lack of functional TJs. Surprisingly, GCs lacked all epithelial markers analyzed, including E-cadherin, cytokeratin 8, and zonula occludens (ZO)-1alpha+. Furthermore, vimentin was expressed by GCs, suggesting a more mesenchymal phenotype. Under calcium-free conditions, small follicles maintained oocyte-GC contact, confirming the importance of calcium-independent nectin at this stage. However, in primary and multilayered follicles, lack of calcium resulted in loss of contact between GCs and oocyte, showing that nectin alone cannot maintain attachment between these two cell types. Lack of classic markers suggests that GCs are not epithelial. Identification of AJs during GC cuboidalization highlights the importance of AJs in regulating initiation of follicle growth.

  5. Recruitment of focal adhesion kinase and paxillin to β1 integrin promotes cancer cell migration via mitogen activated protein kinase activation

    Directory of Open Access Journals (Sweden)

    Ohannessian Arthur

    2004-05-01

    Full Text Available Abstract Background Integrin-extracellular matrix interactions activate signaling cascades such as mitogen activated protein kinases (MAPK. Integrin binding to extracellular matrix increases tyrosine phosphorylation of focal adhesion kinase (FAK. Inhibition of FAK activity by expression of its carboxyl terminus decreases cell motility, and cells from FAK deficient mice also show reduced migration. Paxillin is a focal adhesion protein which is also phosphorylated on tyrosine. FAK recruitment of paxillin to the cell membrane correlates with Shc phosphorylation and activation of MAPK. Decreased FAK expression inhibits papilloma formation in a mouse skin carcinogenesis model. We previously demonstrated that MAPK activation was required for growth factor induced in vitro migration and invasion by human squamous cell carcinoma (SCC lines. Methods Adapter protein recruitment to integrin subunits was examined by co-immunoprecipitation in SCC cells attached to type IV collagen or plastic. Stable clones overexpressing FAK or paxillin were created using the lipofection technique. Modified Boyden chambers were used for invasion assays. Results In the present study, we showed that FAK and paxillin but not Shc are recruited to the β1 integrin cytoplasmic domain following attachment of SCC cells to type IV collagen. Overexpression of either FAK or paxillin stimulated cancer cell migration on type IV collagen and invasion through reconstituted basement membrane which was dependent on MAPK activity. Conclusions We concluded that recruitment of focal adhesion kinase and paxillin to β1 integrin promoted cancer cell migration via the mitogen activated protein kinase pathway.

  6. Composites containing albumin protein or cyanoacrylate adhesives and biodegradable scaffolds: I. Acute wound closure study in a rat model

    Science.gov (United States)

    Hoffman, Grant T.; Soller, Eric C.; Heintzelman, Douglas L.; Duffy, Mark T.; Bloom, Jeffrey N.; Gilmour, Travis M.; Gonnerman, Krista N.; McNally-Heintzelman, Karen M.

    2004-07-01

    Composite adhesives composed of biodegradable scaffolds impregnated with a biological or synthetic adhesive were investigated for use in wound closure as an alternative to using either one of the adhesives alone. Two different scaffold materials were investigated: (i) a synthetic biodegradable material fabricated from poly(L-lactic-co-glycolic acid); and (ii) a biological material, small intestinal sub mucosa, manufactured by Cook BioTech. The biological adhesive was composed of 50%(w/v) bovine serum albumin solder and 0.5mg/ml indocyanine green dye mixed in deionized water, and activated with an 808-nm diode laser. The synthetic adhesive was Ethicon's Dermabond, a 2-octyl-cyanoacrylate. The tensile strength of skin incisions repaired ex vivo in a rat model, by adhesive alone or in combination with a scaffold, as well as the time-to-failure, were measured and compared. The tensile strength of repairs formed using the scaffold-enhanced biological adhesives were on average, 80% stronger than their non-enhanced counterparts, with an accompanying increase in the time-to-failure of the repairs. These results support the theory that a scaffold material with an irregular surface that bridges the wound provides a stronger, more durable and consistent adhesion, due to the distribution of the tensile stress forces over the many micro-adhesions provided by the irregular surface, rather than the one large continuous adhesive contact. This theory is also supported by several previous ex vivo experiments demonstrating enhanced tensile strength of irregular versus smooth scaffold surfaces in identical tissue repairs performed on bovine thoracic aorta, liver, spleen, small intestine and lung tissue.

  7. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2003-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well...... to rewriting on arbitrary adhesive categories....

  8. Crystal structure of linoleate 13R-manganese lipoxygenase in complex with an adhesion protein.

    Science.gov (United States)

    Chen, Yang; Wennman, Anneli; Karkehabadi, Saeid; Engström, Åke; Oliw, Ernst H

    2016-08-01

    The crystal structure of 13R-manganese lipoxygenase (MnLOX) of Gaeumannomyces graminis (Gg) in complex with zonadhesin of Pichia pastoris was solved by molecular replacement. Zonadhesin contains β-strands in two subdomains. A comparison of Gg-MnLOX with the 9S-MnLOX of Magnaporthe oryzae (Mo) shows that the protein fold and the geometry of the metal ligands are conserved. The U-shaped active sites differ mainly due to hydrophobic residues of the substrate channel. The volumes and two hydrophobic side pockets near the catalytic base may sanction oxygenation at C-13 and C-9, respectively. Gly-332 of Gg-MnLOX is positioned in the substrate channel between the entrance and the metal center. Replacements with larger residues could restrict oxygen and substrate to reach the active site. C18 fatty acids are likely positioned with C-11 between Mn(2+)OH2 and Leu-336 for hydrogen abstraction and with one side of the 12Z double bond shielded by Phe-337 to prevent antarafacial oxygenation at C-13 and C-11. Phe-347 is positioned at the end of the substrate channel and replacement with smaller residues can position C18 fatty acids for oxygenation at C-9. Gg-MnLOX does not catalyze the sequential lipoxygenation of n-3 fatty acids in contrast to Mo-MnLOX, which illustrates the different configurations of their substrate channels.

  9. Haemophilus influenzae P4 Interacts With Extracellular Matrix Proteins Promoting Adhesion and Serum Resistance.

    Science.gov (United States)

    Su, Yu-Ching; Mukherjee, Oindrilla; Singh, Birendra; Hallgren, Oskar; Westergren-Thorsson, Gunilla; Hood, Derek; Riesbeck, Kristian

    2016-01-15

    Interaction with the extracellular matrix (ECM) is one of the successful colonization strategies employed by nontypeable Haemophilus influenzae (NTHi). Here we identified Haemophilus lipoprotein e (P4) as a receptor for ECM proteins. Purified recombinant P4 displayed a high binding affinity for laminin (Kd = 9.26 nM) and fibronectin (Kd = 10.19 nM), but slightly less to vitronectin (Kd = 16.51 nM). A P4-deficient NTHi mutant showed a significantly decreased binding to these ECM components. Vitronectin acquisition conferred serum resistance to both P4-expressing NTHi and Escherichia coli transformants. P4-mediated bacterial adherence to pharynx, type II alveolar, and bronchial epithelial cells was mainly attributed to fibronectin. Importantly, a significantly reduced bacterial infection was observed in the middle ear of the Junbo mouse model when NTHi was devoid of P4. In conclusion, our data provide new insight into the role of P4 as an important factor for Haemophilus colonization and subsequent respiratory tract infection.

  10. EFFECTS OF SYSTEMIC FLUCONAZOLE THERAPY ON IN VITRO ADHESION OF CANDIDA ALBICANS TO BUCCAL EPITHELIAL CELLS AND CHANGES OF THE CELL SURFACE PROTEINS OF THE EPITHELIAL CELLS

    Institute of Scientific and Technical Information of China (English)

    吴绍熙; 郭宁如; 侯幼红

    1996-01-01

    This paper presented the effects of systemic fluconazole therapy via intravenous (IV) and oral (PO) administrations on the adhesion of Candida albicans (C. albicans) to the huccal epithelial ceils (BEC) from five treated patients with three candidosis, one mucornlycosis and one sporotrichosis and at the same time,an analysis of the cell surface proteins involving candidal adherent receptor in the BEC of the patients in the course of 7 days were exposed to 3H-leucine radiolabaled C. atbicans for in vitro eandidal adherent assay,and the BEC from first intake day and the last intake day of the patients were extracted by dithiothreitol(DTT)-iodoacetamide treatment for SDS-PAGE. These results indicate that the systemic iluconazole therapy resuks in the inhibitory effect of candldal adhesion to BEC of treated patients to prevent them from oral candidosis for a prolonged time, which is based on the absent surface protein (35KDa) of the BEC.

  11. Interleukin-2 induces beta2-integrin-dependent signal transduction involving the focal adhesion kinase-related protein B (fakB)

    DEFF Research Database (Denmark)

    Brockdorff, J; Kanner, S B; Nielsen, M

    1998-01-01

    B-tyrosine phosphorylation in beta2-integrin-positive T cells. In parallel experiments, IL-2 does not induce or augment tyrosine phosphorylation of p125(FAK). In conclusion, our data indicate that IL-2 induces beta2-integrin-dependent signal transduction events involving the tyrosine kinase substrate fakB.......beta2 integrin molecules are involved in a multitude of cellular events, including adhesion, migration, and cellular activation. Here, we studied the influence of beta2 integrins on interleukin-2 (IL-2)-mediated signal transduction in human CD4(+) T cell lines obtained from healthy donors...... experiments indicate that the IL-2-induced 125-kDa phosphotyrosine protein is the focal adhesion kinase-related protein B (fakB). Thus, IL-2 induces strong tyrosine phosphorylation of fakB in beta2-integrin-positive but not in beta2-integrin-negative T cells, and CD18 mAb selectively blocks IL-2-induced fak...

  12. Lactobacillus Adhesion to Mucus

    Directory of Open Access Journals (Sweden)

    Maxwell L. Van Tassell

    2011-05-01

    Full Text Available Mucus provides protective functions in the gastrointestinal tract and plays an important role in the adhesion of microorganisms to host surfaces. Mucin glycoproteins polymerize, forming a framework to which certain microbial populations can adhere, including probiotic Lactobacillus species. Numerous mechanisms for adhesion to mucus have been discovered in lactobacilli, including partially characterized mucus binding proteins. These mechanisms vary in importance with the in vitro models studied, which could significantly affect the perceived probiotic potential of the organisms. Understanding the nature of mucus-microbe interactions could be the key to elucidating the mechanisms of probiotic adhesion within the host.

  13. Inhibition of focal adhesion kinase (FAK) signaling in focal adhesions decreases cell motility and proliferation.

    OpenAIRE

    1996-01-01

    It has been proposed that the focal adhesion kinase (FAK) mediates focal adhesion formation through tyrosine phosphorylation during cell adhesion. We investigated the role of FAK in focal adhesion structure and function. Loading cells with a glutathione-S-transferase fusion protein (GST-Cterm) containing the FAK focal adhesion targeting sequence, but not the kinase domain, decreased the association of endogenous FAK with focal adhesions. This displacement of endogenous FAK in both BALB/c 3T3 ...

  14. First study on gene expression of cement proteins and potential adhesion-related genes of a membranous-based barnacle as revealed from Next-Generation Sequencing technology

    KAUST Repository

    Lin, Hsiu Chin

    2013-12-12

    This is the first study applying Next-Generation Sequencing (NGS) technology to survey the kinds, expression location, and pattern of adhesion-related genes in a membranous-based barnacle. A total of 77,528,326 and 59,244,468 raw sequence reads of total RNA were generated from the prosoma and the basis of Tetraclita japonica formosana, respectively. In addition, 55,441 and 67,774 genes were further assembled and analyzed. The combined sequence data from both body parts generates a total of 79,833 genes of which 47.7% were shared. Homologues of barnacle cement proteins - CP-19K, -52K, and -100K - were found and all were dominantly expressed at the basis where the cement gland complex is located. This is the main area where transcripts of cement proteins and other potential adhesion-related genes were detected. The absence of another common barnacle cement protein, CP-20K, in the adult transcriptome suggested a possible life-stage restricted gene function and/or a different mechanism in adhesion between membranous-based and calcareous-based barnacles. © 2013 © 2013 Taylor & Francis.

  15. Enhanced protein adsorption and cellular adhesion using transparent titanate nanotube thin films made by a simple and inexpensive room temperature process: application to optical biochips.

    Science.gov (United States)

    Nador, Judit; Orgovan, Norbert; Fried, Miklos; Petrik, Peter; Sulyok, Attila; Ramsden, Jeremy J; Korosi, Laszlo; Horvath, Robert

    2014-10-01

    A new type of titanate nanotube (TNT) coating is investigated for exploitation in biosensor applications. The TNT layers were prepared from stable but additive-free sols without applying any binding compounds. The simple, fast spin-coating process was carried out at room temperature, and resulted in well-formed films around 10nm thick. The films are highly transparent as expected from their nanostructure and may, therefore, be useful as coatings for surface-sensitive optical biosensors to enhance the specific surface area. In addition, these novel coatings could be applied to medical implant surfaces to control cellular adhesion. Their morphology and structure was characterized by spectroscopic ellipsometry (SE) and atomic force microscopy (AFM), and their chemical state by X-ray photoelectron spectroscopy (XPS). For quantitative surface adhesion studies, the films were prepared on optical waveguides. The coated waveguides were shown to still guide light; thus, their sensing capability remains. Protein adsorption and cell adhesion studies on the titanate nanotube films and on smooth control surfaces revealed that the nanostructured titanate enhanced the adsorption of albumin; furthermore, the coatings considerably enhanced the adhesion of living mammalian cells (human embryonic kidney and preosteoblast).

  16. L1 cell adhesion molecule induces melanoma cell motility by activation of mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yi, Young-Su; Baek, Kwang-Soo; Cho, Jae Youl

    2014-06-01

    L1 cell adhesion molecule (L1CAM) is highly expressed in various types of cancer cells and has been implicated in the control of cell proliferation and motility. Recently, L1CAM was reported to induce the motility of melanoma cells, but the mechanism of this induction remains poorly understood. In this study, we investigated the molecular mechanisms by which L1CAM induces the motility of melanoma cells. Unlike other types of cancer cells, B16F10 melanoma cells highly expressed L1CAM at both the RNA and protein levels, and the expression of L1CAM induced AP-1 activity. In accordance to AP-1 activation, MAPK signaling pathways were activated by L1CAM. Inhibition of L1CAM expression by L1CAM-specific siRNA suppressed the activation of MAPKs such as ERK and p38. However, no significant change was observed in JNK activation. As expected, upstream MAP2K, MKK3/6, MAP3K, and TAK1 were also deactivated by the inhibition of L1CAM expression. L1CAM induced the motility of B16F10 cells. Inhibition of L1CAM expression suppressed migration and invasion of B16F10 cells, but no suppressive effect was observed on their proliferation and anti-apoptotic resistance. Treatment of B16F10 cells with U0126, an ERK inhibitor, or SB203580, a p38 inhibitor, suppressed the migration and invasion abilities of B16F10 cells. Taken together, our results suggest that L1CAM induces the motility of B16F10 melanoma cells via the activation of MAPK pathways. This finding provides a more detailed molecular mechanism of L1CAM-mediated induction of melanoma cell motility.

  17. Getting from A to B-exploring the activation motifs of the class B adhesion G protein-coupled receptor subfamily G member 4/GPR112

    DEFF Research Database (Denmark)

    Cornelia Peeters, Miriam; Mos, Iris; Lenselink, Eelke B;

    2016-01-01

    The adhesion G protein-coupled receptors (ADGRs/class B2 G protein-coupled receptors) constitute an ancient family of G protein-coupled receptors that have recently been demonstrated to play important roles in cellular and developmental processes. Here, we describe a first insight...... into the structure-function relationship of ADGRs using the family member ADGR subfamily G member 4 (ADGRG4)/GPR112 as a model receptor. In a bioinformatics approach, we compared conserved, functional elements of the well-characterized class A and class B1 secretin-like G protein-coupled receptors with the ADGRs. We...... identified several potential equivalent motifs and subjected those to mutational analysis. The importance of the mutated residues was evaluated by examining their effect on the high constitutive activity of the N-terminally truncated ADGRG4/GPR112 in a 1-receptor-1-G protein Saccharomyces cerevisiae...

  18. Clay Bells: Edo Inspiration

    Science.gov (United States)

    Wagner, Tom

    2010-01-01

    The ceremonial copper and iron bells at the Smithsonian's National Museum of African Art were the author's inspiration for an interdisciplinary unit with a focus on the contributions various cultures make toward the richness of a community. The author of this article describes an Edo bell-inspired ceramic project incorporating slab-building…

  19. Serine34 phosphorylation of RHO guanine dissociation inhibitor (RHOGDI{alpha}) links signaling from conventional protein kinase C to RHO GTPase in cell adhesion

    DEFF Research Database (Denmark)

    Dovas, Athanassios; Choi, Youngsil; Yoneda, Atsuko

    2010-01-01

    Protein kinase Calpha (PKCalpha) is an essential serine/threonine kinase regulating many signaling networks. At cell adhesion sites, PKCalpha can impact the actin cytoskeleton through its influence on RhoGTPases but the intermediate steps are not well known. One important regulator of Rho......GTPase function is the multifunctional guanine nucleotide dissociation inhibitor RhoGDIalpha that sequesters several related RhoGTPases in an inactive form, but may also target them through interactions with actin-associated proteins. Here it is demonstrated that PKCalpha phosphorylates RhoGDIalpha on serine 34...

  20. α2-Macroglobulin Can Crosslink Multiple Plasmodium falciparum Erythrocyte Membrane Protein 1 (PfEMP1) Molecules and May Facilitate Adhesion of Parasitized Erythrocytes

    DEFF Research Database (Denmark)

    Stevenson, Liz; Laursen, Erik; Cowan, Graeme J;

    2015-01-01

    Rosetting, the adhesion of Plasmodium falciparum-infected erythrocytes to uninfected erythrocytes, involves clonal variants of the parasite protein P. falciparum erythrocyte membrane protein 1 (PfEMP1) and soluble serum factors. While rosetting is a well-known phenotypic marker of parasites......-macroglobulin (α2M), which is both required and sufficient for rosetting mediated by the PfEMP1 protein HB3VAR06 and some other rosette-mediating PfEMP1 proteins. We map the α2M binding site to the C terminal end of HB3VAR06, and demonstrate that α2M can bind at least four HB3VAR06 proteins, plausibly....... Together, our results are evidence that P. falciparum parasites exploit α2M (and IgM) to expand the repertoire of host receptors available for PfEMP1-mediated IE adhesion, such as the erythrocyte carbohydrate moieties that lead to formation of rosettes. It is likely that this mechanism also affects IE...

  1. α2-macroglobulin can crosslink multiple Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) molecules and may facilitate adhesion of parasitized erythrocytes

    DEFF Research Database (Denmark)

    Stevenson, Liz; Laursen, Erik; Cowan, Graeme J;

    2015-01-01

    Rosetting, the adhesion of Plasmodium falciparum-infected erythrocytes to uninfected erythrocytes, involves clonal variants of the parasite protein P. falciparum erythrocyte membrane protein 1 (PfEMP1) and soluble serum factors. While rosetting is a well-known phenotypic marker of parasites......-macroglobulin (α2M), which is both required and sufficient for rosetting mediated by the PfEMP1 protein HB3VAR06 and some other rosette-mediating PfEMP1 proteins. We map the α2M binding site to the C terminal end of HB3VAR06, and demonstrate that α2M can bind at least four HB3VAR06 proteins, plausibly....... Together, our results are evidence that P. falciparum parasites exploit α2M (and IgM) to expand the repertoire of host receptors available for PfEMP1-mediated IE adhesion, such as the erythrocyte carbohydrate moieties that lead to formation of rosettes. It is likely that this mechanism also affects IE...

  2. Dynamic regulation of a cell adhesion protein complex including CADM1 by combinatorial analysis of FRAP with exponential curve-fitting.

    Science.gov (United States)

    Sakurai-Yageta, Mika; Maruyama, Tomoko; Suzuki, Takashi; Ichikawa, Kazuhisa; Murakami, Yoshinori

    2015-01-01

    Protein components of cell adhesion machinery show continuous renewal even in the static state of epithelial cells and participate in the formation and maintenance of normal epithelial architecture and tumor suppression. CADM1 is a tumor suppressor belonging to the immunoglobulin superfamily of cell adhesion molecule and forms a cell adhesion complex with an actin-binding protein, 4.1B, and a scaffold protein, MPP3, in the cytoplasm. Here, we investigate dynamic regulation of the CADM1-4.1B-MPP3 complex in mature cell adhesion by fluorescence recovery after photobleaching (FRAP) analysis. Traditional FRAP analysis were performed for relatively short period of around 10 min. Here, thanks to recent advances in the sensitive laser detector systems, we examine FRAP of CADM1 complex for longer period of 60 min and analyze the recovery with exponential curve-fitting to distinguish the fractions with different diffusion constants. This approach reveals that the fluorescence recovery of CADM1 is fitted to a single exponential function with a time constant (τ) of approximately 16 min, whereas 4.1B and MPP3 are fitted to a double exponential function with two τs of approximately 40-60 sec and 16 min. The longer τ is similar to that of CADM1, suggesting that 4.1B and MPP3 have two distinct fractions, one forming a complex with CADM1 and the other present as a free pool. Fluorescence loss in photobleaching analysis supports the presence of a free pool of these proteins near the plasma membrane. Furthermore, double exponential fitting makes it possible to estimate the ratio of 4.1B and MPP3 present as a free pool and as a complex with CADM1 as approximately 3:2 and 3:1, respectively. Our analyses reveal a central role of CADM1 in stabilizing the complex with 4.1B and MPP3 and provide insight in the dynamics of adhesion complex formation.

  3. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Karin [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden); Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Grawé, Jan [Department of Genetics and Pathology, Uppsala University, Uppsala 75185 (Sweden); McKinney-Freeman, Shannon L. [Department of Hematology, St. Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Daley, George Q. [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Welsh, Michael, E-mail: michael.welsh@mcb.uu.se [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden)

    2013-07-15

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via

  4. Investigating the BSA protein adsorption and bacterial adhesion of Al-alloy surfaces after creating a hierarchical (micro/nano) superhydrophobic structure.

    Science.gov (United States)

    Moazzam, Parisa; Razmjou, Amir; Golabi, Mohsen; Shokri, Dariush; Landarani-Isfahani, Amir

    2016-09-01

    Bacterial adhesion and subsequent biofilm formation on metals such as aluminum (Al) alloys lead to serious issues in biomedical and industrial fields from both an economical and health perspective. Here, we showed that a careful manipulation of Al surface characteristics via a facile two-steps superhydrophobic modification can provide not only biocompatibility and an ability to control protein adsorption and bacterial adhesion, but also address the issue of apparent long-term toxicity of Al-alloys. To find out the roles of surface characteristics, surface modification and protein adsorption on microbial adhesion and biofilm formation, the surfaces were systematically characterized by SEM, EDX, XPS, AFM, FTIR, water contact angle (WCA) goniometry, surface free energy (SFE) measurement, MTT, Bradford, Lowry and microtiter plate assays and also flow-cytometry and potentiostat analyses. Results showed that WCA and SFE changed from 70° to 163° and 36.3 to 0.13 mN m(-1) , respectively. The stable and durable modification led to a substantial reduction in static/dynamic BSA adsorption. The effect of such a treatment on the biofilm formation was analyzed by using three different bacteria of Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. The microtiter plate assay and flow cytometry analysis showed that the modification not only could substantially reduce the bacterial adhesion but this biofouling resistance is independent of bacterium type. An excellent cell viability after exposure of HeLa cells to waters incubated with the modified samples was observed. Finally, the corrosion rate reduced sharply from 856.6 to 0.119 MPY after superhydrophobic modifications, which is an excellent stable corrosion inhibition property. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2220-2233, 2016.

  5. Platelet adhesion: structural and functional diversity of short dystrophin and utrophins in the formation of dystrophin-associated-protein complexes related to actin dynamics.

    Science.gov (United States)

    Cerecedo, Doris; Martínez-Rojas, Dalila; Chávez, Oscar; Martínez-Pérez, Francisco; García-Sierra, Francisco; Rendon, Alvaro; Mornet, Dominique; Mondragón, Ricardo

    2005-12-01

    Platelets are dynamic cell fragments that modify their shape during activation. Utrophin and dystrophins are minor actin-binding proteins present in muscle and non-muscle cytoskeleton. In the present study, we characterised the pattern of Dp71 isoforms and utrophin gene products by immunoblot in human platelets. Two new dystrophin isoforms were found, Dp71f and Dp71 d, as well as the Up71 isoform and the dystrophin-associated proteins, alpha and beta -dystrobrevins. Distribution of Dp71d/Dp71delta110m, Up400/Up71 and dystrophin-associated proteins in relation to the actin cytoskeleton was evaluated by confocal microscopy in both resting and platelets adhered on glass. Formation of two dystrophin-associated protein complexes (Dp71d/Dp71delta110m approximately DAPC and Up400/Up71 approximately DAPC) was demonstrated by co-immunoprecipitation and their distribution in relation to the actin cytoskeleton was characterised during platelet adhesion. The Dp71d/Dp71delta100m approximately DAPC is maintained mainly at the granulomere and is associated with dynamic structures during activation by adhesion to thrombin-coated surfaces. Participation of both Dp71d/Dp71delta110m approximately DAPC and Up400/Up71 approximately DAPC in the biological roles of the platelets is discussed.

  6. Copper modulates zinc metalloproteinase-dependent ectodomain shedding of key signaling and adhesion proteins and promotes the invasion of prostate cancer epithelial cells.

    Science.gov (United States)

    Parr-Sturgess, Catherine A; Tinker, Claire L; Hart, Claire A; Brown, Michael D; Clarke, Noel W; Parkin, Edward T

    2012-10-01

    A disintegrin and metalloproteinases (ADAMs) and matrix metalloproteinases (MMPs) are zinc metalloproteinases (ZMPs) that catalyze the "ectodomain shedding" of a range of cell surface proteins including signaling and adhesion molecules. These "sheddases" are associated with the invasion and metastasis of a range of cancers. Increased serum and tumor tissue levels of copper are also observed in several cancers, although little is known about how the metal might promote disease progression at the molecular level. In the current study, we investigated whether copper might regulate the ectodomain shedding of two key cell surface proteins implicated in the invasion and metastasis of prostate cancer, the Notch ligand Jagged1 and the adhesion molecule E-cadherin, and whether the metal was able to influence the invasion of the prostate cancer epithelial cell line PC3. Physiological copper concentrations stimulated the ZMP-mediated proteolysis of Jagged1 and E-cadherin in cell culture models, whereas other divalent metals had no effect. Copper-mediated Jagged1 proteolysis was also observed following the pretreatment of cells with cycloheximide and in a cell-free membrane system, indicating a posttranslational mechanism of sheddase activation. Finally, the concentrations of copper that stimulated ZMP-mediated protein shedding also enhanced PC3 invasion; an effect that could be negated using a sheddase inhibitor or copper chelators. Collectively, these data implicate copper as an important factor in promoting prostate cancer cell invasion and indicate that the selective posttranslational activation of ZMP-mediated protein shedding might play a role in this process.

  7. Serum Vascular Adhesion Protein-1 Predicts End-Stage Renal Disease in Patients with Type 2 Diabetes.

    Directory of Open Access Journals (Sweden)

    Hung-Yuan Li

    Full Text Available Diabetes is the leading cause of end-stage renal disease (ESRD worldwide. Vascular adhesion protein-1 (VAP-1 participates in inflammation and catalyzes the deamination of primary amines into aldehydes, hydrogen peroxide, and ammonia, both of which are involved in the pathogenesis of diabetic complications. We have shown that serum VAP-1 is higher in patients with diabetes and in patients with chronic kidney disease (CKD, and can predict cardiovascular mortality in subjects with diabetes. In this study, we investigated if serum VAP-1 can predict ESRD in diabetic subjects.In this prospective cohort study, a total of 604 type 2 diabetic subjects were enrolled between 1996 to 2003 at National Taiwan University Hospital, Taiwan, and were followed for a median of 12.36 years. The development of ESRD was ascertained by linking our database with the nationally comprehensive Taiwan Society Nephrology registry. Serum VAP-1 concentrations at enrollment were measured by time-resolved immunofluorometric assay.Subjects with serum VAP-1 in the highest tertile had the highest incidence of ESRD (p<0.001. Every 1-SD increase in serum VAP-1 was associated with a hazard ratio of 1.55 (95%CI 1.12-2.14, p<0.01 for the risk of ESRD, adjusted for smoking, history of cardiovascular disease, body mass index, hypertension, HbA1c, duration of diabetes, total cholesterol, use of statins, ankle-brachial index, estimated GFR, and proteinuria. We developed a risk score comprising serum VAP-1, HbA1c, estimated GFR, and proteinuria, which could predict ESRD with good performance (area under the ROC curve = 0.9406, 95%CI 0.8871-0.9941, sensitivity = 77.3%, and specificity = 92.8%. We also developed an algorithm based on the stage of CKD and a risk score including serum VAP-1, which can stratify these subjects into 3 categories with an ESRD risk of 0.101%/year, 0.131%/year, and 2.427%/year, respectively.In conclusion, serum VAP-1 can predict ESRD and is a useful biomarker to

  8. Defining the gene repertoire and spatiotemporal expression profiles of adhesion G protein-coupled receptors in zebrafish.

    Science.gov (United States)

    Harty, Breanne L; Krishnan, Arunkumar; Sanchez, Nicholas E; Schiöth, Helgi B; Monk, Kelly R

    2015-02-08

    Adhesion G protein-coupled receptors (aGPCRs) are the second largest of the five GPCR families and are essential for a wide variety of physiological processes. Zebrafish have proven to be a very effective model for studying the biological functions of aGPCRs in both developmental and adult contexts. However, aGPCR repertoires have not been defined in any fish species, nor are aGPCR expression profiles in adult tissues known. Additionally, the expression profiles of the aGPCR family have never been extensively characterized over a developmental time-course in any species. Here, we report that there are at least 59 aGPCRs in zebrafish that represent homologs of 24 of the 33 aGPCRs found in humans; compared to humans, zebrafish lack clear homologs of GPR110, GPR111, GPR114, GPR115, GPR116, EMR1, EMR2, EMR3, and EMR4. We find that several aGPCRs in zebrafish have multiple paralogs, in line with the teleost-specific genome duplication. Phylogenetic analysis suggests that most zebrafish aGPCRs cluster closely with their mammalian homologs, with the exception of three zebrafish-specific expansion events in Groups II, VI, and VIII. Using quantitative real-time PCR, we have defined the expression profiles of 59 zebrafish aGPCRs at 12 developmental time points and 10 adult tissues representing every major organ system. Importantly, expression profiles of zebrafish aGPCRs in adult tissues are similar to those previously reported in mouse, rat, and human, underscoring the evolutionary conservation of this family, and therefore the utility of the zebrafish for studying aGPCR biology. Our results support the notion that zebrafish are a potentially useful model to study the biology of aGPCRs from a functional perspective. The zebrafish aGPCR repertoire, classification, and nomenclature, together with their expression profiles during development and in adult tissues, provides a crucial foundation for elucidating aGPCR functions and pursuing aGPCRs as therapeutic targets.

  9. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2004-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well to rewrit...

  10. Polymer composition and substrate influences on the adhesive bonding of a biomimetic, cross-linking polymer.

    Science.gov (United States)

    Matos-Pérez, Cristina R; White, James D; Wilker, Jonathan J

    2012-06-06

    Hierarchical biological materials such as bone, sea shells, and marine bioadhesives are providing inspiration for the assembly of synthetic molecules into complex structures. The adhesive system of marine mussels has been the focus of much attention in recent years. Several catechol-containing polymers are being developed to mimic the cross-linking of proteins containing 3,4-dihydroxyphenylalanine (DOPA) used by shellfish for sticking to rocks. Many of these biomimetic polymer systems have been shown to form surface coatings or hydrogels; however, bulk adhesion is demonstrated less often. Developing adhesives requires addressing design issues including finding a good balance between cohesive and adhesive bonding interactions. Despite the growing number of mussel-mimicking polymers, there has been little effort to generate structure-property relations and gain insights on what chemical traits give rise to the best glues. In this report, we examine the simplest of these biomimetic polymers, poly[(3,4-dihydroxystyrene)-co-styrene]. Pendant catechol groups (i.e., 3,4-dihydroxystyrene) are distributed throughout a polystyrene backbone. Several polymer derivatives were prepared, each with a different 3,4-dihyroxystyrene content. Bulk adhesion testing showed where the optimal middle ground of cohesive and adhesive bonding resides. Adhesive performance was benchmarked against commercial glues as well as the genuine material produced by live mussels. In the best case, bonding was similar to that obtained with cyanoacrylate "Krazy Glue". Performance was also examined using low- (e.g., plastics) and high-energy (e.g., metals, wood) surfaces. The adhesive bonding of poly[(3,4-dihydroxystyrene)-co-styrene] may be the strongest of reported mussel protein mimics. These insights should help us to design future biomimetic systems, thereby bringing us closer to development of bone cements, dental composites, and surgical glues.

  11. Physicists get INSPIREd

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    Particle physicists thrive on information. They first create information by performing experiments or elaborating theoretical conjectures and then they share it through publications and various web tools. The INSPIRE service, just released, will bring state of the art information retrieval to the fingertips of researchers.   Keeping track of the information shared within the particle physics community has long been the task of libraries at the larger labs, such as CERN, DESY, Fermilab and SLAC, as well as the focus of indispensible services like arXiv and those of the Particle Data Group. In 2007, many providers of information in the field came together for a summit at SLAC to see how physics information resources could be enhanced, and the INSPIRE project emerged from that meeting. The vision behind INSPIRE was built by a survey launched by the four labs to evaluate the real needs of the community. INSPIRE responds to these directives from the community by combining the most successful aspe...

  12. Evaluation of C-Reactive Protein, Endothelin-1, Adhesion Molecule(s, and Lipids as Inflammatory Markers in Type 2 Diabetes Mellitus Patients

    Directory of Open Access Journals (Sweden)

    Hala El-Mesallamy

    2007-01-01

    Full Text Available This study compared lipids, the product of lipid peroxidation malondialdehyde (MDA, the acute phase reactant high sensitive C-reactive protein (hsCRP, endothelin-1 (ET-1, P-selectin, intercellular adhesion molecule-1 (ICAM-1, and vascular cell adhesion molecule-1 (VCAM-1 between healthy controls, subjects with ischemic heart disease (IHD and type 2 diabetes mellitus (DM subjects who did not perform coronary artery bypass graft (CABG surgery as well as type 2 DM subjects who performed CABG. HbA1c, lipids, MDA, hsCRP, ET-1, P-selectin, ICAM-1, and VCAM-1 levels were significantly higher in the diabetic groups than in either healthy controls or IHD subjects. In the diabetic groups, there was a negative association among hsCRP and HDL-C. ET-1, ICAM-1 levels and TAG were positively correlated, as do the association between P-selectin, VCAM-1 and HbA1c%. Also a positive relation was found among hsCRP levels and ICAM-1, as well as MDA and ET-1. P-selectin and ICAM-1 were significantly positively correlated. This study indicates that increased level of oxidative stress marker, proinflammatory markers and their downstream effectors adhesion molecules occurs in type 2 DM.

  13. c-Yes regulates cell adhesion at the apical ectoplasmic specialization-blood-testis barrier axis via its effects on protein recruitment and distribution

    Science.gov (United States)

    Xiao, Xiang; Mruk, Dolores D.

    2013-01-01

    During spermatogenesis, extensive restructuring takes place at the cell-cell interface since developing germ cells migrate progressively from the basal to the adluminal compartment of the seminiferous epithelium. Since germ cells per se are not motile cells, their movement relies almost exclusively on the Sertoli cell. Nonetheless, extensive exchanges in signaling take place between these cells in the seminiferous epithelium. c-Yes, a nonreceptor protein tyrosine kinase belonging to the Src family kinases (SFKs) and a crucial signaling protein, was recently shown to be upregulated at the Sertoli cell-cell interface at the blood-testis barrier (BTB) at stages VIII–IX of the seminiferous epithelial cycle of spermatogenesis. It was also highly expressed at the Sertoli cell-spermatid interface known as apical ectoplasmic specialization (apical ES) at stage V to early stage VIII of the epithelial cycle during spermiogenesis. Herein, it was shown that the knockdown of c-Yes by RNAi in vitro and in vivo affected both Sertoli cell adhesion at the BTB and spermatid adhesion at the apical ES, causing a disruption of the Sertoli cell tight junction-permeability barrier function, germ cell loss from the seminiferous epithelium, and also a loss of spermatid polarity. These effects were shown to be mediated by changes in distribution and/or localization of adhesion proteins at the BTB (e.g., occludin, N-cadherin) and at the apical ES (e.g., nectin-3) and possibly the result of changes in the underlying actin filaments at the BTB and the apical ES. These findings implicate that c-Yes is a likely target of male contraceptive research. PMID:23169788

  14. c-Yes regulates cell adhesion at the apical ectoplasmic specialization-blood-testis barrier axis via its effects on protein recruitment and distribution.

    Science.gov (United States)

    Xiao, Xiang; Mruk, Dolores D; Cheng, C Yan

    2013-01-15

    During spermatogenesis, extensive restructuring takes place at the cell-cell interface since developing germ cells migrate progressively from the basal to the adluminal compartment of the seminiferous epithelium. Since germ cells per se are not motile cells, their movement relies almost exclusively on the Sertoli cell. Nonetheless, extensive exchanges in signaling take place between these cells in the seminiferous epithelium. c-Yes, a nonreceptor protein tyrosine kinase belonging to the Src family kinases (SFKs) and a crucial signaling protein, was recently shown to be upregulated at the Sertoli cell-cell interface at the blood-testis barrier (BTB) at stages VIII-IX of the seminiferous epithelial cycle of spermatogenesis. It was also highly expressed at the Sertoli cell-spermatid interface known as apical ectoplasmic specialization (apical ES) at stage V to early stage VIII of the epithelial cycle during spermiogenesis. Herein, it was shown that the knockdown of c-Yes by RNAi in vitro and in vivo affected both Sertoli cell adhesion at the BTB and spermatid adhesion at the apical ES, causing a disruption of the Sertoli cell tight junction-permeability barrier function, germ cell loss from the seminiferous epithelium, and also a loss of spermatid polarity. These effects were shown to be mediated by changes in distribution and/or localization of adhesion proteins at the BTB (e.g., occludin, N-cadherin) and at the apical ES (e.g., nectin-3) and possibly the result of changes in the underlying actin filaments at the BTB and the apical ES. These findings implicate that c-Yes is a likely target of male contraceptive research.

  15. Freeze-dried allograft-mediated gene or protein delivery of growth and differentiation factor 5 reduces reconstructed murine flexor tendon adhesions

    DEFF Research Database (Denmark)

    Svensson, Sys Hasslund; Dadali, Tulin; Ulrich-Vinther, Michael

    2014-01-01

    Advances in allograft processing have opened new horizons for clinical adaptation of flexor tendon allografts as delivery scaffolds for antifibrotic therapeutics. Recombinant adeno-associated-virus (rAAV) gene delivery of the growth and differentiation factor 5 (GDF-5) has been previously...... associated with antifibrotic effects in a mouse model of flexor tendoplasty. In this study, we compared the effects of loading freeze-dried allografts with different doses of GDF-5 protein or rAAV-Gdf5 on flexor tendon healing and adhesions. We first optimized the protein and viral loading parameters using...... reverse transcription polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and in vivo bioluminescent imaging. We then reconstructed flexor digitorum longus (FDL) tendons of the mouse hindlimb with allografts loaded with low and high doses of recombinant GDF-5 protein and r...

  16. The effect of stromelysin-1 (MMP-3) on non-collagenous extracellular matrix proteins of demineralized dentin and the adhesive properties of restorative resins.

    Science.gov (United States)

    Boukpessi, T; Menashi, S; Camoin, L; Tencate, J M; Goldberg, M; Chaussain-Miller, C

    2008-11-01

    Dentin non-collagenous matrix components (NCPs) are structural proteins involved in the formation, the architecture and the mineralization of the extracellular matrix (ECM). We investigated here how recombinant metalloproteinase stromelysin-1, also termed MMP-3, initiates the release of ECM molecules from artificially demineralized human dentin. Analysis of the supernatants by Western blotting reveals that MMP-3 extracts PGs (decorin, biglycan), and also a series of phosphorylated proteins: dentin sialoprotein (DSP), osteopontin (OPN), bone sialoprotein (BSP) and MEPE, but neither dentin matrix protein-1 (DMP1), another member of the SIBLING family, nor osteocalcin (OC), a non-phosphorylated matrix molecule. After treatment of dentin surfaces by MMP-3, scanning electron microscope (SEM) examination of resin replica shows an increased penetration of the resin into the dentin tubules when compared to surfaces only treated by demineralizing solutions. This preclinical investigation suggests that MMP-3 may be used to improve the adhesive properties of restorative materials.

  17. Mechanical stimulation of C2C12 cells increases m-calpain expression, focal adhesion plaque protein degradation and cell differentiation

    DEFF Research Database (Denmark)

    Grossi, Alberto; Lawson, Moira Ann

    Abstract Mechanical stimulation of C2C12 cells increases m-calpain expression, focal adhesion plaque protein degradation and cell differentiation. A. Grossi, M. A. Lawson; Department of Food Science, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark The process of muscle...... development and growth is a complex sequence of events whereby muscle cells respond to a number of stimuli in order to form organised muscle tissue. Increase in muscle mass is greatly influenced by the rate of skeletal muscle protein synthesis and degradation, processes that can be altered by mechanical...... forces. Stretch- or load-induced signaling is now beginning to be understood as a factor which affects the mass and phenotype of muscles as well as the expression of a number of proteins within muscle cells. Use of magnetic field to produce mechanical forces to stimulate cell populations has been well...

  18. PDMS bonding to a bio-friendly photoresist via self-polymerized poly(dopamine) adhesive for complex protein micropatterning inside microfluidic channels.

    Science.gov (United States)

    Kim, Miju; Song, Kwang Hoon; Doh, Junsang

    2013-12-01

    Protein micropatterned surfaces integrated with microfluidics are useful in numerous bioanalytical and biological applications. In this study, we demonstrated the fabrication of complex protein micropatterned surfaces within poly(dimethylsiloxane) (PDMS) microfluidic channels by attaching the PDMS channels to bio-friendly photoresist films and subsequently performing microscope projection photolithography (MPP). A muscle-inspired poly(dopamine) (PDA) coating was employed to mediate the bonding between the PDMS and the bio-friendly photoresist poly(2,2-dimethoxy nitrobenzyl methacrylate-r-methyl methacrylate-r-poly(ethylene glycol) methacrylate) (PDMP). By adjusting the dip-coating time for the PDA coating, we could successfully introduce sufficient amounts of functional groups on the PDMP surfaces to mediate strong bonding between the PDMS channels and the PDA-coated PDMP thin films with minimal alteration of the surface properties of the PDMP thin films that are critical for protein micropatterning. Using this novel bonding strategy, we successfully fabricated multiple protein micropatterns and gradient micropatterns of proteins within microfluidic channels. The technique developed in this study will be useful for the fabrication of complex biochips for multiplex bioassays and fundamental cell biological studies.

  19. Changes in the vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and c-reactive protein following administration of aqueous extract of piper sarmentosum on experimental rabbits fed with cholesterol diet

    Directory of Open Access Journals (Sweden)

    Al-Mekhlafi Hesham M

    2011-01-01

    Full Text Available Abstract Background Inflammation process plays an important role in the development of atherosclerosis. Hypercholesterolemia is one of the major risk factors for atherosclerosis. The present study aimed to evaluate the effect of aqueous extract of Piper sarmentosum (P.s on inflammatory markers like vascular cell adhesion molecule-1 (VCAM-1, intercellular adhesion molecule-1 (ICAM-1, and C-reactive protein (CRP. Methods Forty two male New Zealand white rabbits were divided equally into seven groups; (i C- control group fed normal rabbit chow (ii CH- cholesterol diet (1%cholesterol (iii X1- 1% cholesterol with water extract of P.s (62.5 mg/kg (iv X2- 1% cholesterol with water extract of P.s (125 mg/kg (v X3- 1% cholesterol with water extract of P.s (250 mg/kg (vi X4- 1% cholesterol with water extract of P.s (500 mg/kg and (vii SMV group fed with 1% cholesterol supplemented with simvistatin drug (1.2 mg/kg. All animals were treated for 10 weeks. Blood serum was taken for observing the inflammatory markers at the beginning and end of the experiment. Results Rabbits fed with 1% cholesterol diet (CH showed significant increase in the level of VCAM-1, ICAM-1 and CRP compared to the C group. The levels of VCAM-1, ICAM-1 and CRP in the 1% cholesterol group and supplemented with P.s (500 mg/kg were significantly reduced compared to the cholesterol group. Similar results were also reported with simvistatin group. Conclusion These results suggest that the supplementation of Piper sarmentosum extract could inhibit inflammatory markers which in turn could prevent atherosclerosis.

  20. Alternagin-C, a disintegrin-like protein from the venom of Bothrops alternatus, modulates a2ß1 integrin-mediated cell adhesion, migration and proliferation

    Directory of Open Access Journals (Sweden)

    Selistre-de-Araujo H.S.

    2005-01-01

    Full Text Available The alpha2ß1 integrin is a major collagen receptor that plays an essential role in the adhesion of normal and tumor cells to the extracellular matrix. Alternagin-C (ALT-C, a disintegrin-like protein purified from the venom of the Brazilian snake Bothrops alternatus, competitively interacts with the alpha2ß1 integrin, thereby inhibiting collagen binding. When immobilized in plate wells, ALT-C supports the adhesion of fibroblasts as well as of human vein endothelial cells (HUVEC and does not detach cells previously bound to collagen I. ALT-C is a strong inducer of HUVEC proliferation in vitro. Gene expression analysis was done using an Affimetrix HU-95A probe array with probe sets of ~10,000 human genes. In human fibroblasts growing on collagen-coated plates, ALT-C up-regulates the expression of several growth factors including vascular endothelial growth factor, as well as some cell cycle control genes. Up-regulation of the vascular endothelial growth factor gene and other growth factors could explain the positive effect on HUVEC proliferation. ALT-C also strongly activates protein kinase B phosphorylation, a signaling event involved in endothelial cell survival and angiogenesis. In human neutrophils, ALT-C has a potent chemotactic effect modulated by the intracellular signaling cascade characteristic of integrin-activated pathways. Thus, ALT-C acts as a survival factor, promoting adhesion, migration and endothelial cell proliferation after binding to alpha2ß1 integrin on the cell surface. The biological activities of ALT-C may be helpful as a therapeutic strategy in tissue regeneration as well as in the design of new therapeutic agents targeting alpha2ß1 integrin.

  1. Inspiration is "Mission Critical"

    Science.gov (United States)

    McCarthy, D. W.; DeVore, E.; Lebofsky, L.

    2014-07-01

    In spring 2013, the President's budget proposal restructured the nation's approach to STEM education, eliminating ˜$50M of NASA Science Mission Directorate (SMD) funding with the intent of transferring it to the Dept. of Education, National Science Foundation, and Smithsonian Institution. As a result, Education and Public Outreach (EPO) would no longer be a NASA mission requirement and funds that had already been competed, awarded, and productively utilized were lost. Since 1994, partnerships of scientists, engineers, and education specialists were required to create innovative approaches to EPO, providing a direct source of inspiration for today's youth that may now be lost. Although seldom discussed or evaluated, "inspiration" is the beginning of lasting education. For decades, NASA's crewed and robotic missions have motivated students of all ages and have demonstrated a high degree of leverage in society. Through personal experiences we discuss (1) the importance of inspiration in education, (2) how NASA plays a vital role in STEM education, (3) examples of high-leverage educational materials showing why NASA should continue embedding EPO specialists within mission teams, and (4) how we can document the role of inspiration. We believe that personal histories are an important means of assessing the success of EPO. We hope this discussion will lead other people to document similar stories of educational success and perhaps to undertake longitudinal studies of the impact of inspiration.

  2. Nectin/PRR: an immunoglobulin-like cell adhesion molecule recruited to cadherin-based adherens junctions through interaction with Afadin, a PDZ domain-containing protein.

    Science.gov (United States)

    Takahashi, K; Nakanishi, H; Miyahara, M; Mandai, K; Satoh, K; Satoh, A; Nishioka, H; Aoki, J; Nomoto, A; Mizoguchi, A; Takai, Y

    1999-05-03

    We have isolated a novel actin filament-binding protein, named afadin, localized at cadherin-based cell-cell adherens junctions (AJs) in various tissues and cell lines. Afadin has one PDZ domain, three proline-rich regions, and one actin filament-binding domain. We found here that afadin directly interacted with a family of the immunoglobulin superfamily, which was isolated originally as the poliovirus receptor-related protein (PRR) family consisting of PRR1 and -2, and has been identified recently to be the alphaherpes virus receptor. PRR has a COOH-terminal consensus motif to which the PDZ domain of afadin binds. PRR and afadin were colocalized at cadherin-based cell-cell AJs in various tissues and cell lines. In E-cadherin-expressing EL cells, PRR was recruited to cadherin-based cell-cell AJs through interaction with afadin. PRR showed Ca2+-independent cell-cell adhesion activity. These results indicate that PRR is a cell-cell adhesion molecule of the immunoglobulin superfamily which is recruited to cadherin-based cell-cell AJs through interaction with afadin. We rename PRR as nectin (taken from the Latin word "necto" meaning "to connect").

  3. Mechanical stimulation of C2C12 cells increases m-calpain expression, focal adhesion plaque protein degradation and cell differentiation

    DEFF Research Database (Denmark)

    Grossi, Alberto; Lawson, Moira Ann

    Abstract Mechanical stimulation of C2C12 cells increases m-calpain expression, focal adhesion plaque protein degradation and cell differentiation. A. Grossi, M. A. Lawson; Department of Food Science, Royal Veterinary and Agricultural University, Frederiksberg C, Denmark The process of muscle...... documented and has been shown to affect transcription of specific gene sequences, protein synthesis, the immune system and increase in Ca2+ influx. The past 10 years has seen a dramatic increase in the understanding of how proteolytic enzymes such as calpains can affect the growth of muscle. In vivo studies...... have shown that m-calpain is necessary for myoblast fusion leading to the formation of muscle fibers and that inhibition of this enzyme restricts myotube formation. Whether there is a link between stretchor load induced signaling and m-calpain expression and activation is not known. Using a magnetic...

  4. Capillarity-based switchable adhesion.

    Science.gov (United States)

    Vogel, Michael J; Steen, Paul H

    2010-02-23

    Drawing inspiration from the adhesion abilities of a leaf beetle found in nature, we have engineered a switchable adhesion device. The device combines two concepts: The surface tension force from a large number of small liquid bridges can be significant (capillarity-based adhesion) and these contacts can be quickly made or broken with electronic control (switchable). The device grabs or releases a substrate in a fraction of a second via a low-voltage pulse that drives electroosmotic flow. Energy consumption is minimal because both the grabbed and released states are stable equilibria that persist with no energy added to the system. Notably, the device maintains the integrity of an array of hundreds to thousands of distinct interfaces during active reconfiguration from droplets to bridges and back, despite the natural tendency of the liquid toward coalescence. We demonstrate the scaling of adhesion strength with the inverse of liquid contact size. This suggests that strengths approaching those of permanent bonding adhesives are possible as feature size is scaled down. In addition, controllability is fast and efficient because the attachment time and required voltage also scale down favorably. The device features compact size, no solid moving parts, and is made of common materials.

  5. An eye for inspiration

    Science.gov (United States)

    2009-11-01

    The discovery that the eye of a particular mantis shrimp has an achromatic quarter-waveplate that is superior to modern-day devices could be a source of inspiration to those designing optical components. Nature Photonics spoke to Nicholas Roberts, one of the researchers involved in the study.

  6. Inspire & innovate : Endbericht

    NARCIS (Netherlands)

    Cornelissen, T.; Lugtenaar, M.; Balendonck, J.; Ruckelshausen, A.; Wit, de R.

    2008-01-01

    Met het project Inspire & Innovate helpt de EU Nederlandse en Duitse bedrijven in met name de sectoren Food en Life Sciences op weg. Het project is bedoeld voor MKB-bedrijven in de Euregio Rijn-Waal en de EUREGIO die inhoudelijke en financiële ondersteuning zoeken om hun innovatieplannen door te

  7. Ndebele Inspired Houses

    Science.gov (United States)

    Rice, Nicole

    2012-01-01

    The house paintings of the South African Ndebele people are more than just an attempt to improve the aesthetics of a community; they are a source of identity and significance for Ndebele women. In this article, the author describes an art project wherein students use the tradition of Ndebele house painting as inspiration for creating their own…

  8. Inspire & innovate : Endbericht

    NARCIS (Netherlands)

    Cornelissen, T.; Lugtenaar, M.; Balendonck, J.; Ruckelshausen, A.; Wit, de R.

    2008-01-01

    Met het project Inspire & Innovate helpt de EU Nederlandse en Duitse bedrijven in met name de sectoren Food en Life Sciences op weg. Het project is bedoeld voor MKB-bedrijven in de Euregio Rijn-Waal en de EUREGIO die inhoudelijke en financiële ondersteuning zoeken om hun innovatieplannen door te

  9. Nature as Inspiration

    Science.gov (United States)

    Tank, Kristina; Moore, Tamara; Strnat, Meg

    2015-01-01

    This article describes the final lesson within a seven-day STEM and literacy unit that is part of the Picture STEM curriculum (pictureSTEM. org) and uses engineering to integrate science and mathematics learning in a meaningful way (Tank and Moore 2013). For this engineering challenge, students used nature as a source of inspiration for designs to…

  10. An Ark of Inspiration.

    Science.gov (United States)

    King, Steve

    2001-01-01

    Describes an art project suitable for middle and high school students in which they either combine identifiable parts from different animals to create one creature or take one animal and creatively distort it. Explains that this lesson enables students to be satisfied with their animal-inspired artwork. (CMK)

  11. Nature as Inspiration

    Science.gov (United States)

    Tank, Kristina; Moore, Tamara; Strnat, Meg

    2015-01-01

    This article describes the final lesson within a seven-day STEM and literacy unit that is part of the Picture STEM curriculum (pictureSTEM. org) and uses engineering to integrate science and mathematics learning in a meaningful way (Tank and Moore 2013). For this engineering challenge, students used nature as a source of inspiration for designs to…

  12. Materials from Mussel-Inspired Chemistry for Cell and Tissue Engineering Applications.

    Science.gov (United States)

    Madhurakkat Perikamana, Sajeesh Kumar; Lee, Jinkyu; Lee, Yu Bin; Shin, Young Min; Lee, Esther J; Mikos, Antonios G; Shin, Heungsoo

    2015-09-14

    Current advances in biomaterial fabrication techniques have broadened their application in different realms of biomedical engineering, spanning from drug delivery to tissue engineering. The success of biomaterials depends highly on the ability to modulate cell and tissue responses, including cell adhesion, as well as induction of repair and immune processes. Thus, most recent approaches in the field have concentrated on functionalizing biomaterials with different biomolecules intended to evoke cell- and tissue-specific reactions. Marine mussels produce mussel adhesive proteins (MAPs), which help them strongly attach to different surfaces, even under wet conditions in the ocean. Inspired by mussel adhesiveness, scientists discovered that dopamine undergoes self-polymerization at alkaline conditions. This reaction provides a universal coating for metals, polymers, and ceramics, regardless of their chemical and physical properties. Furthermore, this polymerized layer is enriched with catechol groups that enable immobilization of primary amine or thiol-based biomolecules via a simple dipping process. Herein, this review explores the versatile surface modification techniques that have recently been exploited in tissue engineering and summarizes polydopamine polymerization mechanisms, coating process parameters, and effects on substrate properties. A brief discussion of polydopamine-based reactions in the context of engineering various tissue types, including bone, blood vessels, cartilage, nerves, and muscle, is also provided.

  13. Mussel-inspired nano-building block assemblies for mimicking extracellular matrix microenvironments with multiple functions.

    Science.gov (United States)

    Wang, Zhenming; Jia, Zhanrong; Jiang, Yanan; Li, Pengfei; Han, Lu; Lu, Xiong; Ren, Fuzeng; Wang, Kefeng; Yuan, Huiping

    2017-08-03

    The assembly of nano-building blocks is an effective way to produce artificial extracellular matrix microenvironments with hierarchical micro/nano structures. However, it is hard to assemble different types of nano-building blocks, to form composite coatings with multiple functions, by traditional layer-by-layer (LbL) self-assembly methods. Inspired by the mussel adhesion mechanism, we developed polydopamine (PDA)-decorated bovine serum albumin microspheres (BSA-MS) and nano-hydroxyapatite (nano-HA), and assembled them to form bioactive coatings with micro/nano structures encapsulating bone morphogenetic protein-2 (BMP-2). First, PDA-decorated nano-HA (nano-pHA) was obtained by oxidative polymerization of dopamine on nano-HA. Second, BMP-2-encapsulated BSA microspheres were prepared through desolvation, and then were also decorated by PDA (pBSA-MS). Finally, the nano-pHA and pBSA-MS were assembled using the adhesive properties of PDA. Bone marrow stromal cell cultures and in vivo implantation, showed that the pHA/pBSA (BMP-2) coatings can promote cell adhesion, proliferation, and benefited for osteoinductivity. PDA decoration was also applied to assemble various functional nanoparticles, such as nano-HA, polystyrene, and Fe3O4 nanoparticles. In summary, this study provides a novel strategy for the assembly of biofunctional nano-building blocks, which surpasses traditional LbL self-assembly of polyelectrolytes, and can find broad applications in bioactive agents delivery or multi-functional coatings.

  14. Crk adaptor protein-induced phosphorylation of Gab1 on tyrosine 307 via Src is important for organization of focal adhesions and enhanced cell migration

    Institute of Scientific and Technical Information of China (English)

    Takuya Watanabe; Masumi Tsuda; Yoshinori Makino; Tassos Konstantinou; Hiroshi Nishihara; Tokifumi Majima; Akio Minami; Stephan M Feller; Shinya Tanaka

    2009-01-01

    Upon growth factor stimulation, the scaffold protein, Gabl, is tyrosine phosphorylated and subsequently the adaptor protein, Crk, transmits signals from Gabl. We have previously shown that Crk overexpression, which is detectable in various human cancers, induces tyrosine phosphorylation of Gab1 without extraceilular stimuli. In the present study, the underlying mechanisms were further investigated. Mutational analyses of Crkll demonstrated that the SH2 domain, but not the SH3(N) or the regulatory Y221 residue of Crkll, is critical for the induction of Gabl-Y307 phosphorylation. SH2 mutation of Crkll also decreased the interaction with Gab1. In GST pull-down assay, Crk-SH2 bound to wild-type Gabl, whereas Crk-SH3(N) interacted with the Gabl mutant, which lacks the clus-tered tyrosine region (residues 242-410). Tyrosine phosphorylation of Gabl was induced by all Crk family proteins, but not other SH2-containing signalling adaptors. Src-family kinase inhibitor, PP2, abrogates Crk-induced tyrosine phosphorylations of Gabl. Y307 phosphorylation was undetectable in fibroblasts lacking Src, Yes, and Fyn, even upon overexpression of Crk, whereas cells lacking only Yes and Fyn still contained Gabl with phosphorylated Y307. Furthermore, Crk induced the phosphorylation of Src-Y416; accordingly the interaction between Crk and Csk was increased. The GabI-Y307F mutant failed to localize near the plasma membrane even upon HGF stimulation and decreased cell migration. Moreover, Gabl-Y307F disturbed the localization of Crk, FAK, and paxiilin, which are the typical components of focal adhesions. Taken together, these results indicate that Crk facilitates tyrosine phosphory-lation of Gabl-Y307 through Src, contributing to the organization of focal adhesions and enhanced cell migration, thereby possibly promoting human cancer development.

  15. Estrogen and pure antiestrogen fulvestrant (ICI 182 780) augment cell–matrigel adhesion of MCF-7 breast cancer cells through a novel G protein coupled estrogen receptor (GPR30)-to-calpain signaling axis

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan; Li, Zheng; He, Yan; Shang, Dandan; Pan, Jigang; Wang, Hongmei; Chen, Huamei; Zhu, Zhuxia [Department of Physiology/Cancer Research Group, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China); Wan, Lei [Department of Pharmacology, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China); Wang, Xudong, E-mail: xdwang@gmc.edu.cn [Department of Physiology/Cancer Research Group, Guiyang Medical University School of Basic Medicine, 9 Beijing Road, Guiyang 550004, Guizhou (China)

    2014-03-01

    Fulvestrant (ICI 182 780, ICI) has been used in treating patients with hormone-sensitive breast cancer, yet initial or acquired resistance to endocrine therapies frequently arises and, in particular, cancer recurs as metastasis. We demonstrate here that both 17-beta-estradiol (E2) and ICI enhance cell adhesion to matrigel in MCF-7 breast cancer cells, with increased autolysis of calpain 1 (large subunit) and proteolysis of focal adhesion kinase (FAK), indicating calpain activation. Additionally, either E2 or ICI induced down-regulation of estrogen receptor α without affecting G protein coupled estrogen receptor 30 (GPR30) expression. Interestingly, GPR30 agonist G1 triggered calpain 1 autolysis but not calpain 2, whereas ER agonist diethylstilbestrol caused no apparent calpain autolysis. Furthermore, the actions of E2 and ICI on calpain and cell adhesion were tremendously suppressed by G15, or knockdown of GPR30. E2 and ICI also induced phosphorylation of extracellular regulated protein kinases 1 and 2 (ERK1/2), and suppression of ERK1/2 phosphorylation by U0126 profoundly impeded calpain activation triggered by estrogenic and antiestrogenic stimulations indicating implication of ERK1/2 in the GPR30-mediated action. Lastly, the E2- or ICI-induced cell adhesion was dramatically impaired by calpain-specific inhibitors, ALLN or calpeptin, suggesting requirement of calpain in the GPR30-associated action. These data show that enhanced cell adhesion by E2 and ICI occurs via a novel GPR30-ERK1/2-calpain pathway. Our results indicate that targeting the GPR30 signaling may be a potential strategy to reduce metastasis and improve the efficacy of antiestrogens in treatment of advanced breast cancer. - Highlights: • Estrogen and ICI augment adhesion to matrigel with calpain activation in MCF-7 cells. • GPR30 mediates cell–matrigel adhesion and calpain activation via ERK1/2. • Calpain is required in the cell–matrigel adhesion induced by E2 and ICI.

  16. The adaptor protein SAP directly associates with PECAM-1 and regulates PECAM-1-mediated-cell adhesion in T-like cell lines.

    Science.gov (United States)

    Proust, Richard; Crouin, Catherine; Gandji, Leslie Yewakon; Bertoglio, Jacques; Gesbert, Franck

    2014-04-01

    SAP is a small cytosolic adaptor protein expressed in hematopoietic lineages whose main function is to regulate intracellular signaling pathways induced by the triggering of members of the SLAM receptor family. In this paper, we have identified the adhesion molecule PECAM-1 as a new partner for SAP in a conditional yeast two-hybrid screen. PECAM-1 is an immunoglobulin-like molecule expressed by endothelial cells and leukocytes, which possesses both pro- and anti-inflammatory properties. However, little is known about PECAM-1 functions in T cells. We show that SAP directly and specifically interacts with the cytosolic tyrosine 686 of PECAM-1. We generated different T-like cell lines in which SAP or PECAM-1 are expressed or down modulated and we demonstrate that a diminished SAP expression correlates with a diminished PECAM-1-mediated adhesion. Although SAP has mainly been shown to associate with SLAM receptors, we evidence here that SAP is a new actor downstream of PECAM-1. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. MUC16/CA125 in the Context of Modular Proteins with an Annotated Role in Adhesion-Related Processes: In Silico Analysis

    Directory of Open Access Journals (Sweden)

    Ninoslav Mitic

    2012-08-01

    Full Text Available Mucin 16 (MUC16 is a type I transmembrane protein, the extracellular portion of which is shed after proteolytic degradation and is denoted as CA125 antigen, a well known tumor marker for ovarian cancer. Regarding its polypeptide and glycan structures, as yet there is no detailed insight into their heterogeneity and ligand properties, which may greatly influence its function and biomarker potential. This study was aimed at obtaining further insight into the biological capacity of MUC16/CA125, using in silico analysis of corresponding mucin sequences, including similarity searches as well as GO (gene ontology-based function prediction. The results obtained pointed to the similarities within extracellular serine/threonine rich regions of MUC16 to sequences of proteins expressed in evolutionary distant taxa, all having in common an annotated role in adhesion-related processes. Specifically, a homology to conserved domains from the family of herpesvirus major outer envelope protein (BLLF1 was found. In addition, the possible involvement of MUC16/CA125 in carbohydrate-binding interactions or cellular transport of protein/ion was suggested.

  18. Surface modification of aramid fibers by bio-inspired poly(dopamine) and epoxy functionalized silane grafting.

    Science.gov (United States)

    Sa, Rina; Yan, Yan; Wei, Zhenhai; Zhang, Liqun; Wang, Wencai; Tian, Ming

    2014-12-10

    A novel biomimetic surface modification method for meta-aramid (MPIA) fibers and the improvement on adhesion with rubber matrix was demonstrated. Inspired by the composition of adhesive proteins in mussels, we used dopamine (DOPA) self-polymerization to form thin, surface-adherent poly(dopamine) (PDA) films onto the surface of MPIA fibers simply by immersing MPIA fibers in a dopamine solution at room temperature. An epoxy functionalized silane (KH560) grafting was then carried out on the surface of the poly(dopamine)-coated MPIA, either by a "one-step" or "two-step" method, to introduce an epoxy group onto the MPIA fiber surface. The surface composition and microstructure of the modified MPIA was characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated successful grafting of KH560 on the PDA-coated MPIA surface. A single-fiber pull-out test was applied to evaluate the adhesion of MPIA fibers with the rubber matrix. Compared with the untreated MPIA fibers, the adhesion strength between the modified MPIA fibers by "one step" method with rubber matrix has an increase of 62.5%.

  19. Amino acid sequences mediating vascular cell adhesion molecule 1 binding to integrin alpha 4: homologous DSP sequence found for JC polyoma VP1 coat protein

    Directory of Open Access Journals (Sweden)

    Michael Andrew Meyer

    2013-07-01

    Full Text Available The JC polyoma viral coat protein VP1 was analyzed for amino acid sequences homologies to the IDSP sequence which mediates binding of VLA-4 (integrin alpha 4 to vascular cell adhesion molecule 1. Although the full sequence was not found, a DSP sequence was located near the critical arginine residue linked to infectivity of the virus and binding to sialic acid containing molecules such as integrins (3. For the JC polyoma virus, a DSP sequence was found at residues 70, 71 and 72 with homology also noted for the mouse polyoma virus and SV40 virus. Three dimensional modeling of the VP1 molecule suggests that the DSP loop has an accessible site for interaction from the external side of the assembled viral capsid pentamer.

  20. Amino Acid Sequences Mediating Vascular Cell Adhesion Molecule 1 Binding to Integrin Alpha 4: Homologous DSP Sequence Found for JC Polyoma VP1 Coat Protein.

    Science.gov (United States)

    Meyer, Michael Andrew

    2013-01-01

    The JC polyoma viral coat protein VP1 was analyzed for amino acid sequences homologies to the IDSP sequence which mediates binding of VLA-4 (integrin alpha 4) to vascular cell adhesion molecule 1. Although the full sequence was not found, a DSP sequence was located near the critical arginine residue linked to infectivity of the virus and binding to sialic acid containing molecules such as integrins (3). For the JC polyoma virus, a DSP sequence was found at residues 70, 71 and 72 with homology also noted for the mouse polyoma virus and SV40 virus. Three dimensional modeling of the VP1 molecule suggests that the DSP loop has an accessible site for interaction from the external side of the assembled viral capsid pentamer.

  1. Direct binding of syndecan-4 cytoplasmic domain to the catalytic domain of protein kinase C alpha (PKC alpha) increases focal adhesion localization of PKC alpha

    DEFF Research Database (Denmark)

    Lim, Ssang-Taek; Longley, Robert L; Couchman, John R

    2003-01-01

    Syndecan-4 is a transmembrane heparan sulfate proteoglycan that acts as a coreceptor with integrins in focal adhesion formation. The central region of syndecan-4 cytoplasmic domain (4V; LGKKPIYKK) binds phosphatidylinositol 4,5-bisphosphate, and together they regulate protein kinase C alpha (PKC...... alpha) activity. Syndecan 4V peptide directly potentiates PKC alpha activity, leading to "superactivation" of the enzyme, apparently through an interaction with its catalytic domain. We now have performed yeast two-hybrid and in vitro binding assays to determine the interaction sites between 4V and PKC...... alpha. Full-length PKC alpha weakly interacted with 4V by yeast two-hybrid assays, but PKC alpha constructs that lack the pseudosubstrate region or constructs of the whole catalytic domain interacted more strongly. A mutated 4V sequence (4V(YF): LGKKPIFKK) did not interact with PKC alpha, indicating...

  2. The adhesion protein IgSF9b is coupled to neuroligin 2 via S-SCAM to promote inhibitory synapse development

    OpenAIRE

    Woo, Jooyeon; Kwon, Seok-Kyu; Nam, Jungyong; Choi, Seungwon; Takahashi, Hideto; Krueger, Dilja; Park, Joohyun; Lee, Yeunkum; Bae, Jin Young; Lee, Dongmin; Ko, Jaewon; Kim, Hyun; Kim, Myoung-Hwan; Bae, Yong Chul; Chang, Sunghoe

    2013-01-01

    Synaptic adhesion molecules regulate diverse aspects of synapse formation and maintenance. Many known synaptic adhesion molecules localize at excitatory synapses, whereas relatively little is known about inhibitory synaptic adhesion molecules. Here we report that IgSF9b is a novel, brain-specific, homophilic adhesion molecule that is strongly expressed in GABAergic interneurons. IgSF9b was preferentially localized at inhibitory synapses in cultured rat hippocampal and cortical interneurons an...

  3. Mussel-inspired Functionalization of Cotton for Nano-catalyst Support and Its Application in a Fixed-bed System with High Performance

    OpenAIRE

    Jiangbo Xi; Junwu Xiao; Fei Xiao; Yunxia Jin; Yue Dong; Feng Jing; Shuai Wang

    2016-01-01

    Inspired by the composition of adhesive and reductive proteins secreted by marine mussels, polydopamine (PDA) was used to coat cotton microfiber (CMF), and then acted as reducing agent for the growth of Pd nanoparticles on PDA coated CMF (PDA@CMF) composites. The resultant CMF@PDA/Pd composites were then packed in a column for the further use in fixed-bed system. For the catalysis of the reduction of 4-nitrophenol, the flow rate of the 4-aminophenol solution (0.5 mM) was as high as 60 mL/min....

  4. Biological adhesion of the flatworm Macrostomum lignano relies on a duo-gland system and is mediated by a cell type-specific intermediate filament protein

    NARCIS (Netherlands)

    Lengerer, Birgit; Pjeta, Robert; Wunderer, Julia; Rodrigues, Marcelo; Arbore, Roberto; Schaerer, Lukas; Berezikov, Eugene; Hess, Michael W.; Pfaller, Kristian; Egger, Bernhard; Obwegeser, Sabrina; Salvenmoser, Willi; Ladurner, Peter

    2014-01-01

    Background: Free-living flatworms, in both marine and freshwater environments, are able to adhere to and release from a substrate several times within a second. This reversible adhesion relies on adhesive organs comprised of three cell types: an adhesive gland cell, a releasing gland cell, and an an

  5. Inspiral into Gargantua

    CERN Document Server

    Gralla, Samuel E; Warburton, Niels

    2016-01-01

    We model the inspiral of a compact object into a more massive black hole rotating very near the theoretical maximum. We find that once the body enters the near-horizon regime the gravitational radiation is characterized by a constant frequency, equal to (twice) the horizon frequency, with an exponentially damped profile. This contrasts with the usual "chirping" behavior and, if detected, would constitute a "smoking gun" for a near-extremal black hole in nature.

  6. Quantum-Inspired Maximizer

    Science.gov (United States)

    Zak, Michail

    2008-01-01

    A report discusses an algorithm for a new kind of dynamics based on a quantum- classical hybrid-quantum-inspired maximizer. The model is represented by a modified Madelung equation in which the quantum potential is replaced by different, specially chosen 'computational' potential. As a result, the dynamics attains both quantum and classical properties: it preserves superposition and entanglement of random solutions, while allowing one to measure its state variables, using classical methods. Such optimal combination of characteristics is a perfect match for quantum-inspired computing. As an application, an algorithm for global maximum of an arbitrary integrable function is proposed. The idea of the proposed algorithm is very simple: based upon the Quantum-inspired Maximizer (QIM), introduce a positive function to be maximized as the probability density to which the solution is attracted. Then the larger value of this function will have the higher probability to appear. Special attention is paid to simulation of integer programming and NP-complete problems. It is demonstrated that the problem of global maximum of an integrable function can be found in polynomial time by using the proposed quantum- classical hybrid. The result is extended to a constrained maximum with applications to integer programming and TSP (Traveling Salesman Problem).

  7. Biologically inspired intelligent robots

    Science.gov (United States)

    Bar-Cohen, Yoseph; Breazeal, Cynthia

    2003-07-01

    Humans throughout history have always sought to mimic the appearance, mobility, functionality, intelligent operation, and thinking process of biological creatures. This field of biologically inspired technology, having the moniker biomimetics, has evolved from making static copies of human and animals in the form of statues to the emergence of robots that operate with realistic behavior. Imagine a person walking towards you where suddenly you notice something weird about him--he is not real but rather he is a robot. Your reaction would probably be "I can't believe it but this robot looks very real" just as you would react to an artificial flower that is a good imitation. You may even proceed and touch the robot to check if your assessment is correct but, as oppose to the flower case, the robot may be programmed to respond physical and verbally. This science fiction scenario could become a reality as the current trend continues in developing biologically inspired technologies. Technology evolution led to such fields as artificial muscles, artificial intelligence, and artificial vision as well as biomimetic capabilities in materials science, mechanics, electronics, computing science, information technology and many others. This paper will review the state of the art and challenges to biologically-inspired technologies and the role that EAP is expected to play as the technology evolves.

  8. Inspiring a generation

    CERN Multimedia

    2012-01-01

    The motto of the 2012 Olympic and Paralympic Games is ‘Inspire a generation’ so it was particularly pleasing to see science, the LHC and Higgs bosons featuring so strongly in the opening ceremony of the Paralympics last week.   It’s a sign of just how far our field has come that such a high-profile event featured particle physics so strongly, and we can certainly add our support to that motto. If the legacy of London 2012 is a generation inspired by science as well as sport, then the games will have more than fulfilled their mission. Particle physics has truly inspiring stories to tell, going well beyond Higgs and the LHC, and the entire community has played its part in bringing the excitement of frontier research in particle physics to a wide audience. Nevertheless, we cannot rest on our laurels: maintaining the kind of enthusiasm for science we witnessed at the Paralympic opening ceremony will require constant vigilance, and creative thinking about ways to rea...

  9. Perceptually-Inspired Computing

    Directory of Open Access Journals (Sweden)

    Ming Lin

    2015-08-01

    Full Text Available Human sensory systems allow individuals to see, hear, touch, and interact with the surrounding physical environment. Understanding human perception and its limit enables us to better exploit the psychophysics of human perceptual systems to design more efficient, adaptive algorithms and develop perceptually-inspired computational models. In this talk, I will survey some of recent efforts on perceptually-inspired computing with applications to crowd simulation and multimodal interaction. In particular, I will present data-driven personality modeling based on the results of user studies, example-guided physics-based sound synthesis using auditory perception, as well as perceptually-inspired simplification for multimodal interaction. These perceptually guided principles can be used to accelerating multi-modal interaction and visual computing, thereby creating more natural human-computer interaction and providing more immersive experiences. I will also present their use in interactive applications for entertainment, such as video games, computer animation, and shared social experience. I will conclude by discussing possible future research directions.

  10. Shear adhesion strength of aligned electrospun nanofibers.

    Science.gov (United States)

    Najem, Johnny F; Wong, Shing-Chung; Ji, Guang

    2014-09-01

    Inspiration from nature such as insects' foot hairs motivates scientists to fabricate nanoscale cylindrical solids that allow tens of millions of contact points per unit area with material substrates. In this paper, we present a simple yet robust method for fabricating directionally sensitive shear adhesive laminates. By using aligned electrospun nylon-6, we create dry adhesives, as a succession of our previous work on measuring adhesion energies between two single free-standing electrospun polymer fibers in cross-cylinder geometry, randomly oriented membranes and substrate, and peel forces between aligned fibers and substrate. The synthetic aligned cylindrical solids in this study are electrically insulating and show a maximal Mode II shear adhesion strength of 27 N/cm(2) on a glass slide. This measured value, for the purpose of comparison, is 270% of that reported from gecko feet. The Mode II shear adhesion strength, based on a commonly known "dead-weight" test, is 97-fold greater than the Mode I (normal) adhesion strength of the same. The data indicate a strong shear binding on and easy normal lifting off. Anisotropic adhesion (Mode II/Mode I) is pronounced. The size and surface boundary effects, crystallinity, and bending stiffness of fibers are used to understand these electrospun nanofibers, which vastly differ from otherwise known adhesive technologies. The anisotropic strength distribution is attributed to a decreasing fiber diameter and an optimized laminate thickness, which, in turn, influences the bending stiffness and solid-state "wettability" of points of contact between nanofibers and surface asperities.

  11. Focal Adhesion Kinases in Adhesion Structures and Disease

    OpenAIRE

    2012-01-01

    Cell adhesion to the extracellular matrix (ECM) is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organiza...

  12. Cbf11 and Cbf12, the fission yeast CSL proteins, play opposing roles in cell adhesion and coordination of cell and nuclear division

    Energy Technology Data Exchange (ETDEWEB)

    Prevorovsky, Martin; Grousl, Tomas; Stanurova, Jana; Rynes, Jan [Department of Cell Biology, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43, Prague 2 (Czech Republic); Nellen, Wolfgang [Department of Genetics, Kassel University, Heinrich Plett Strasse 40, 34132 Kassel (Germany); Puta, Frantisek [Department of Cell Biology, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43, Prague 2 (Czech Republic); Folk, Petr, E-mail: folk@natur.cuni.cz [Department of Cell Biology, Faculty of Science, Charles University in Prague, Vinicna 7, 128 43, Prague 2 (Czech Republic)

    2009-05-01

    The CSL (CBF1/RBP-J{kappa}/Suppressor of Hairless/LAG-1) family is comprised of transcription factors essential for metazoan development, mostly due to their involvement in the Notch receptor signaling pathway. Recently, we identified two novel classes of CSL genes in the genomes of several fungal species, organisms lacking the Notch pathway. In this study, we characterized experimentally cbf11{sup +} and cbf12{sup +}, the two CSL genes of Schizosaccharomyces pombe, in order to elucidate the CSL function in fungi. We provide evidence supporting their identity as genuine CSL genes. Both cbf11{sup +} and cbf12{sup +} are non-essential; they have distinct expression profiles and code for nuclear proteins with transcription activation potential. Significantly, we demonstrated that Cbf11 recognizes specifically the canonical CSL response element GTG{sup A}/{sub G}GAA in vitro. The deletion of cbf11{sup +} is associated with growth phenotypes and altered colony morphology. Furthermore, we found that Cbf11 and Cbf12 play opposite roles in cell adhesion, nuclear and cell division and their coordination. Disturbed balance of the two CSL proteins leads to cell separation defects (sep phenotype), cut phenotype, and high-frequency diploidization in heterothallic strains. Our data show that CSL proteins operate in an organism predating the Notch pathway, which should be of relevance to the understanding of (Notch-independent) CSL functions in metazoans.

  13. Biochemical features of the adhesion G protein-coupled receptor CD97 related to its auto-proteolysis and HeLa cell attachment activities.

    Science.gov (United States)

    Yang, Li-Yun; Liu, Xiao-Fang; Yang, Yang; Yang, Lin-Lin; Liu, Kai-Wen; Tang, Yu-Bo; Zhang, Min; Tan, Min-Jia; Cheng, Shan-Mei; Xu, Ye-Chun; Yang, Huai-Yu; Liu, Zhi-Jie; Song, Gao-Jie; Huang, Wei

    2017-01-01

    CD97 belongs to the adhesion GPCR family characterized by a long ECD linked to the 7TM via a GPCR proteolytic site (GPS) and plays important roles in modulating cell migration and invasion. CD97 (EGF1-5) is a splicing variant of CD97 that recognizes a specific ligand chondroitin sulfate on cell membranes and the extracellular matrix. The aim of this study was to elucidate the extracellular molecular basis of the CD97 EGF1-5 isoform in protein expression, auto-proteolysis and cell adhesion, including epidermal growth factor (EGF)-like domain, GPCR autoproteolysis-inducing (GAIN) domain, as well as GPS mutagenesis and N-glycosylation. Both wild-type (WT) CD97-ECD and its truncated, GPS mutated, PNGase F-deglycosylated, and N-glycosylation site mutated forms were expressed and purified. The auto-proteolysis of the proteins was analyzed with Western blotting and SDS-PAGE. Small angle X-ray scattering (SAXS) and molecular modeling were used to determine a structural profile of the properly expressed receptor. Potential N-glycosylation sites were identified using MS and were modulated with PNGase F digestion and glyco-site mutations. A flow cytometry-based HeLa cell attachment assay was used for all aforementioned CD97 variants to elucidate the molecular basis of CD97-HeLa interactions. A unique concentration-dependent GPS auto-proteolysis was observed in CD97 EGF1-5 isoform with the highest concentration (4 mg/mL) per sample was self-cleaved much faster than the lower concentration (0.1 mg/mL), supporting an intermolecular mechanism of auto-proteolysis that is distinct to the reported intramolecular mechanism for other CD97 isoforms. N-glycosylation affected the auto-proteolysis of CD97 EGF1-5 isoform in a similar way as the other previously reported CD97 isoforms. SAXS data for WT and deglycosylated CD97ECD revealed a spatula-like shape with GAIN and EGF domains constituting the body and handle, respectively. Structural modeling indicated a potential interaction

  14. Vascular remodeling alters adhesion protein and cytoskeleton reactions to inflammatory stimuli resulting in enhanced permeability increases in rat venules.

    Science.gov (United States)

    Yuan, Dong; He, Pingnian

    2012-10-01

    Vascular remodeling has been implicated in many inflammation-involved diseases. This study aims to investigate the microvascular remodeling-associated alterations in cell-cell adhesion and cytoskeleton reactions to inflammatory stimuli and their impact on microvessel permeability. Experiments were conducted in individually perfused rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (Lp), and endothelial intracellular calcium concentration, [Ca(2+)](i), was measured in fura-2-perfused vessels. Alterations in VE-cadherin and F-actin arrangement were examined by confocal imaging. Vascular wall cellular composition and structural changes were evaluated by electron microscopy. Vessels exposed to platelet activating factor (PAF) on day 1 were reevaluated 3 days later in rats that had undergone survival surgery. Initial PAF exposure and surgical disturbance increased microvascular wall thickness along with perivascular cell proliferation and altered F-actin arrangement. Although basal permeability was not changed, upon reexposure to PAF, peak endothelial [Ca(2+)](i) was augmented and the peak Lp was 9.3 ± 1.7 times higher than that of day 1. In contrast to patterns of PAF-induced stress fiber formation and VE-cadherin redistribution observed in day 1 vessels, the day 4 vessels at the potentiated Lp peak exhibited wide separations of VE-cadherin between endothelial cells and striking stress fibers throughout the vascular walls. Confocal images and ultrastructural micrographs also revealed that the largely separated VE-cadherin and endothelial gaps were completely covered by F-actin bundles in extended pericyte processes at the PAF-induced Lp peak. These results indicate that inflammation-induced vascular remodeling increased endothelial susceptibility to inflammatory stimuli with augmented Ca(2+) response resulting in upregulated contractility and potentiated permeability increase. Weakened adhesions between the endothelial

  15. Gender and age peculiarities of content changes of protein C, von Willebrand factor, vascular cell adhesion molecules sVCAM-1 in patients with acute left ventricle Q-wave myocardial infarction

    Directory of Open Access Journals (Sweden)

    S. M. Kyselov

    2015-04-01

    Full Text Available Markers of hemostasis have an influence on the state of postinfarction remodeling processes. Aim. In order to study the gender and age peculiarities, to determine the predictive value of the protein C, von Willebrand factor and vascular cell adhesion molecules sVCAM-1 concentration, we examined 76 patients with acute Q-wave myocardial infarction. Methods and results. On the 1st day of the disease, higher concentrations of protein C were detected in young women, vascular cell adhesion molecules sVCAM-1 - in men of any age. On the 10th day of the disease, both in men and women increase in the content of protein C, reducing the concentration of von Willebrand factor and vascular cell adhesion molecules sVCAM-1 were detected. Conclusion. Protein C has the highest prognostic potential in relation to the formation of heart aneurysm after Q-wave myocardial infarction in women of young age, and von Willebrand factor and vascular cell adhesion molecules sVCAM-1 - in older men.

  16. Exploring natural silk protein sericin for regenerative medicine: an injectable, photoluminescent, cell-adhesive 3D hydrogel.

    Science.gov (United States)

    Wang, Zheng; Zhang, Yeshun; Zhang, Jinxiang; Huang, Lei; Liu, Jia; Li, Yongkui; Zhang, Guozheng; Kundu, Subhas C; Wang, Lin

    2014-11-20

    Sericin, a major component of silk, has a long history of being discarded as a waste during silk processing. The value of sericin for tissue engineering is underestimated and its potential application in regenerative medicine has just begun to be explored. Here we report the successful fabrication and characterization of a covalently-crosslinked 3D pure sericin hydrogel for delivery of cells and drugs. This hydrogel is injectable, permitting its implantation through minimally invasive approaches. Notably, this hydrogel is found to exhibit photoluminescence, enabling bioimaging and in vivo tracking. Moreover, this hydrogel system possesses excellent cell-adhesive capability, effectively promoting cell attachment, proliferation and long-term survival of various types of cells. Further, the sericin hydrogel releases bioactive reagents in a sustained manner. Additionally, this hydrogel demonstrates good elasticity, high porosity, and pH-dependent degradation dynamics, which are advantageous for this sericin hydrogel to serve as a delivery vehicle for cells and therapeutic drugs. With all these unique features, it is expected that this sericin hydrogel will have wide utility in the areas of tissue engineering and regenerative medicine.

  17. The glypiated neuronal cell adhesion molecule contactin/F11 complexes with src-family protein tyrosine kinase Fyn.

    Science.gov (United States)

    Zisch, A H; D'Alessandri, L; Amrein, K; Ranscht, B; Winterhalter, K H; Vaughan, L

    1995-06-01

    Glycosyl phosphatidylinositol-anchored glycoproteins of the immunoglobulin superfamily play an important role in the formation of neuronal networks during development. The mechanism whereby neuronal GPI-linked molecules transduce recognition signals remains to be established. Analysis of detergent-resistant immune-complexes reveals that the glypiated neuronal cell adhesion molecule contactin/F11 specifically complexes with the cytoplasmic, nonreceptor type src-family tyrosine kinase Fyn. Antibody-mediated cross-linking of contactin/F11 on embryonic chick neuronal cells leads to an increase of the Fyn-activity coprecipitated with contactin/F11, and elevates phosphorylation of an additional 75/80 K component within the contactin/F11-immune-complex. Additionally, binding of ligands, i.e., contactin/F11-specific antibody or tenascin-R, a natural ligand of contactin/F11, to the surface of HeLa transfectants expressing contactin/F11, causes capping of contactin/F11 and a concomitant change in the distribution of the intracellular kinase Fyn, thus confirming their physical association. This indicates that contactin/F11-mediated signaling requires Fyn.

  18. Adhesive plasters

    Science.gov (United States)

    Holcombe, Jr., Cressie E.; Swain, Ronald L.; Banker, John G.; Edwards, Charlene C.

    1978-01-01

    Adhesive plaster compositions are provided by treating particles of Y.sub.2 O.sub.3, Eu.sub.2 O.sub.3, Gd.sub.2 O.sub.3 or Nd.sub.2 O.sub.3 with dilute acid solutions. The resulting compositions have been found to spontaneously harden into rigid reticulated masses resembling plaster of Paris. Upon heating, the hardened material is decomposed into the oxide, yet retains the reticulated rigid structure.

  19. Focal adhesion kinase and mitogen-activated protein kinases are involved in chondrocyte activation by the 29-kDa amino-terminal fibronectin fragment.

    Science.gov (United States)

    Gemba, Takefumi; Valbracht, Jean; Alsalameh, Saifeddin; Lotz, Martin

    2002-01-11

    The 29-kDa amino-terminal fibronectin fragment (FN-f) has a potent chondrolytic effect and is thought to be involved in cartilage degradation in arthritis. However, little is known about signal transduction pathways that are activated by FN-f. Here we demonstrated that FN-f induced nitric oxide (NO) production from human articular chondrocytes. Expression of inducible nitric-oxide synthase (iNOS) mRNA and NO production were observed at 6 and 48 h after FN-f treatment, respectively. Interleukin-1beta (IL-1beta) mRNA up-regulation was stimulated by FN-f in human chondrocytes. To address the possibility that FN-f-induced NO release is mediated by IL-1beta production, the effect of IL-1 receptor antagonist (IL-1ra) was determined. IL-1ra partially inhibited FN-f-induced NO release although it almost completely inhibited IL-1beta-induced NO release. Tyrosine phosphorylation of focal adhesion kinase was induced transiently by FN-f treatment. Blocking antibodies to alpha(5) or beta(1) integrin and Arg-Gly-Asp-containing peptides did not inhibit FN-f-induced NO production. PP2, a Src family kinase inhibitor, or cytochalasin D, which selectively disrupts the network of actin filaments, inhibited both FAK phosphorylation and NO production induced by FN-f, but the phosphatidylinositol 3-kinase inhibitor wortmannin had no effect. Analysis of mitogen-activated protein kinases (MAPK) showed activation of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase, and p38 MAPK. High concentrations of SB203580, which inhibit both JNK and p38 MAPK, and PD98059 a selective inhibitor of MEK1/2 that blocks ERK activation, inhibited FN-f induced NO production. These data suggest that focal adhesion kinase and MAPK mediate FN-f induced activation of human articular chondrocytes.

  20. #IWD2016 Academic Inspiration

    DEFF Research Database (Denmark)

    Meier, Ninna

    2016-01-01

    What academics or books have inspired you in your writing and research, or helped to make sense of the world around you? In this feature essay, Ninna Meier returns to her experience of reading Hannah Arendt as she sought to understand work and how it relates to value production in capitalist...... economies. Meier recounts how Arendt’s book On Revolution (1963) forged connective threads between the ‘smallest parts’ and the ‘largest wholes’ and showed how academic work is never fully relegated to the past, but can return in new iterations across time....

  1. Impaired function of the blood-testis barrier during aging is preceded by a decline in cell adhesion proteins and GTPases.

    Directory of Open Access Journals (Sweden)

    Catriona Paul

    Full Text Available With increasing age comes many changes in the testis, including germ cell loss. Cell junctions in the testis tether both seminiferous epithelial and germ cells together and assist in the formation of the blood-testis barrier (BTB, which limits transport of biomolecules, ions and electrolytes from the basal to the adluminal compartment and protects post-meiotic germ cells. We hypothesize that as male rats age the proteins involved in forming the junctions decrease and that this alters the ability of the BTB to protect the germ cells. Pachytene spermatocytes were isolated from Brown Norway rat testes at 4 (young and 18 (aged months of age using STA-PUT velocity sedimentation technique. RNA was extracted and gene expression was assessed using Affymetrix rat 230 2.0 whole rat genome microarrays. Microarray data were confirmed by q-RT-PCR and protein expression by Western blotting. Of the genes that were significantly decreased by at least 1.5 fold, 70 were involved in cell adhesion; of these, at least 20 are known to be specifically involved in junction dynamics within the seminiferous epithelium. The mRNA and protein levels of Jam2, Ocln, cdh2 (N-cadherin, ctnna (α-catenin, and cldn11 (involved in adherens junctions, among others, were decreased by approximately 50% in aged spermatocytes. In addition, the GTPases Rac1 and cdc42, involved in the recruitment of cadherins to the adherens junctions, were similarly decreased. It is therefore not surprising that with lower expression of these proteins that the BTB becomes diminished with age. We saw, using a FITC tracer, a gradual collapse of the BTB between 18 and 24 months. This provides the opportunity for harmful substances and immune cells to cross the BTB and cause the disruption of spermatogenesis that is observed with increasing age.

  2. The focal adhesion-associated proteins DOCK5 and GIT2 comprise a rheostat in control of epithelial invasion

    DEFF Research Database (Denmark)

    Frank, Scott R; Köllmann, C P; van Lidth de Jeude, J F

    2017-01-01

    DOCK proteins are guanine nucleotide exchange factors for Rac and Cdc42 GTPases. DOCK1 is the founding member of the family and acts downstream of integrins via the canonical Crk-p130Cas complex to activate Rac GTPases in numerous contexts. In contrast, DOCK5, which possesses the greatest similar......:10.1038/onc.2016.345....

  3. Enterococcal surface protein Esp is not essential for cell adhesion and intestinal colonization of Enterococcus faecium in mice

    NARCIS (Netherlands)

    Heikens, E.; Leendertse, M.; Wijnands, L.M.; van Luit-Asbroek, M.; Bonten, M.J.M.; van der Poll, T.; Willems, R.J.L.

    2009-01-01

    ABSTRACT: BACKGROUND: Enterococcus faecium has globally emerged as a cause of hospital-acquired infections with high colonization rates in hospitalized patients. The enterococcal surface protein Esp, identified as a potential virulence factor, is specifically linked to nosocomial clonal lineages tha

  4. Inhibition of Adhesion of Enteropathogenic Escherichia coli to HEp-2 Cells by Binding of a Novel Peptide to EspB Protein.

    Science.gov (United States)

    Li, Duoyun; Chen, Zhong; Cheng, Hang; Zheng, Jin-Xin; Pan, Wei-Guang; Yang, Wei-Zhi; Yu, Zhi-Jian; Deng, Qi-Wen

    2016-09-01

    Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. The translocator EspB is a key virulence factor in the process of the attaching and effacing effect of EPEC and plays a critical role in the pathogenesis of the bacteria. In this study, we aimed to select the peptides binding to EspB protein by phage display library and further investigate whether these peptides can decrease the extent of invasion and virulence of EPEC on host cells by targeting to EspB protein. The expression and purification of EspB protein from E. coli was demonstrated by Western blotting. The Ph.D. 12-mer peptide phage display library was used to screen the candidate peptides binding specifically to EspB protein. Furthermore, the affinity of these candidate peptides bound to EspB was identified by enzyme-linked immunosorbent assay (ELISA). Moreover, we investigated whether these screened peptides could decrease the adherence ratio of EPEC to HEp-2 cells with increasing concentration. Successful purification of EspB protein from pET21b-EspB-transformed E. coli was identified by Western blotting. Then, the candidate peptides including phages 6, 7, 8, and 12 were screened by the Ph.D. 12-mer peptide phage display library and ELISA test demonstrated that their affinity binding to EspB protein was high compared with the control. Functional analysis indicated that synthetic peptide-6 (YFPYSHTSPRQP) significantly decreased the adherence ratio of EPEC to HEp-2 cells with increasing concentration (P < 0.01). Peptide-6 (100 µg/mL) could lead to a 40 % decrease in the adherence ratio of EPEC to HEp-2 cells compared with control (P < 0.01). However, the other three peptides at different concentrations showed only a slight ability to block the adherence of EPEC to host cells. Our data provided a potential strategy to inhibit the adhesion of EPEC to epithelial cells by a candidate peptide targeted toward EspB protein.

  5. Peptides from Pisum sativum L. enzymatic protein digest with anti-adhesive activity against Helicobacter pylori: structure-activity and inhibitory activity against BabA, SabA, HpaA and a fibronectin-binding adhesin.

    Science.gov (United States)

    Niehues, Michael; Euler, Marco; Georgi, Gilda; Mank, Marko; Stahl, Bernd; Hensel, Andreas

    2010-12-01

    Identification of anti-adhesive peptides against Helicobacter pylori obtained by enzymatic hydrolysis of seed proteins from Pisum sativum L. (Fabaceae). Bioassay-guided fractionation of protein tryptic digest by ultrafiltration, size exclusion chromatography (SEC) and reversed phase chromatography (RPC) were used. Identification of bioactive peptides was achieved by MALDI-TOF-MS. Adhesion of H. pylori was monitored by two different assays, using a quantitative in vitro assay on human AGS cells with evaluation of bacterial binding by flow cytometry, beside a semi-quantitative in situ adhesion assay using FITC-labelled H. pylori on human stomach tissue sections. From two highly active fractions (F3, F3.3) two anti-adhesive peptides (S3, S5) were identified. Neither F3 nor S3 or S5 had any cytotoxic effect against H. pylori. By hemagglutination assay and semiquantitative dot blot overlay assay with immobilized ligands it was shown that F3 interacts specifically with H. pylori adhesins BabA, SabA, HpaA and a fibronectin-binding adhesin, while S3 and S5 inhibit only BabA. It was demonstrated that BabA, usually interacting with carbohydrate motifs such as fucosylated blood group antigens, interacts with the peptide moieties. Bioactive peptides from pea protein could be applied as functional ingredients for protecting infants and children against infections such as H. pylori. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. When science inspires art

    CERN Multimedia

    Anaïs Vernède

    2011-01-01

    On Tuesday 18 January 2011, artist Pipilotti Rist came to CERN to find out how science could provide her with a source of inspiration for her art and perhaps to get ideas for future work. Pipilotti, who is an eclectic artist always on the lookout for an original source of inspiration, is almost as passionate about physics as she is about art.   Ever Is Over All, 1997, audio video installation by Pipilotti Rist.  View of the installation at the National Museum for Foreign Art, Sofia, Bulgaria. © Pipilotti Rist. Courtesy the artist and Hauser & Wirth. Photo by Angel Tzvetanov. Swiss video-maker Pipilotti Rist (her real name is Elisabeth Charlotte Rist), who is well-known in the international art world for her highly colourful videos and creations, visited CERN for the first time on Tuesday 18 January 2011.  Her visit represented a trip down memory lane, since she originally studied physics before becoming interested in pursuing a career as an artist and going on to de...

  7. Focal Adhesion Kinases in Adhesion Structures and Disease

    Directory of Open Access Journals (Sweden)

    Pierre P. Eleniste

    2012-01-01

    Full Text Available Cell adhesion to the extracellular matrix (ECM is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organization and role of focal adhesions, podosomes, and invadopodia in different cells. In addition, we discuss the role of the tyrosine kinases, FAK, Pyk2, and Src, which are critical for the function of the different adhesion structures. Finally, we discuss the essential role of these tyrosine kinases from the perspective of human diseases.

  8. Focal adhesion kinases in adhesion structures and disease.

    Science.gov (United States)

    Eleniste, Pierre P; Bruzzaniti, Angela

    2012-01-01

    Cell adhesion to the extracellular matrix (ECM) is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organization and role of focal adhesions, podosomes, and invadopodia in different cells. In addition, we discuss the role of the tyrosine kinases, FAK, Pyk2, and Src, which are critical for the function of the different adhesion structures. Finally, we discuss the essential role of these tyrosine kinases from the perspective of human diseases.

  9. Cytomegalovirus Destruction of Focal Adhesions Revealed in a High-Throughput Western Blot Analysis of Cellular Protein Expression† ▿

    OpenAIRE

    Stanton, Richard James; McSharry, Brian Patrick; Rickards, Carole Ruth; Wang, Edward Chung Yern; Tomasec, Peter; Wilkinson, Gavin William Grahame

    2007-01-01

    Human cytomegalovirus (HCMV) systematically manages the expression of cellular functions, rather than exerting the global shutoff of host cell protein synthesis commonly observed with other herpesviruses during the lytic cycle. While microarray technology has provided remarkable insights into viral control of the cellular transcriptome, HCMV is known to encode multiple mechanisms for posttranscriptional and posttranslation regulation of cellular gene expression. High-throughput Western blotti...

  10. Scaffold-forming and Adhesive Contributions of Synthetic Laminin-binding Proteins to Basement Membrane Assembly*S⃞

    OpenAIRE

    McKee, Karen K.; Capizzi, Stephanie; Yurchenco, Peter D.

    2009-01-01

    Laminins that possess three short arms contribute to basement membrane assembly by anchoring to cell surfaces, polymerizing, and binding to nidogen and collagen IV. Although laminins containing the α4 and α5 subunits are expressed in α2-deficient congenital muscular dystrophy, they may be ineffective substitutes because they bind weakly to cell surfaces and/or because they lack the third arm needed for polymerization. We asked whether linker proteins engineered to bind...

  11. Adhesion and cohesion.

    Science.gov (United States)

    von Fraunhofer, J Anthony

    2012-01-01

    The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  12. Adhesion and Cohesion

    Directory of Open Access Journals (Sweden)

    J. Anthony von Fraunhofer

    2012-01-01

    Full Text Available The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  13. Adsorption of enamel matrix proteins to a bovine-derived bone grafting material and its regulation of cell adhesion, proliferation, and differentiation.

    Science.gov (United States)

    Miron, Richard J; Bosshardt, Dieter D; Hedbom, Erik; Zhang, Yufeng; Haenni, Beat; Buser, Daniel; Sculean, Anton

    2012-07-01

    The use of various combinations of enamel matrix derivative (EMD) and grafting materials has been shown to promote periodontal wound healing/regeneration. However, the downstream cellular behavior of periodontal ligament (PDL) cells and osteoblasts has not yet been studied. Furthermore, it is unknown to what extent the bleeding during regenerative surgery may influence the adsorption of exogenous proteins to the surface of bone grafting materials and the subsequent cellular behavior. In the present study, the aim is to test EMD adsorption to the surface of natural bone mineral (NBM) particles in the presence of blood and determine the effect of EMD coating to NBM particles on downstream cellular pathways, such as adhesion, proliferation, and differentiation of primary human osteoblasts and PDL cells. NBM particles were precoated in various settings with EMD or human blood and analyzed for protein adsorption patterns via fluorescent imaging and high-resolution immunocytochemistry with an anti-EMD antibody. Cell attachment and cell proliferation were quantified using fluorescent double-stranded DNA-binding dye. Cell differentiation was analyzed using real-time polymerase chain reaction for genes encoding runt-related transcription factor 2, alkaline phosphatase (ALP), osteocalcin (OC), and collagen1α1 (COL1A1), and mineralization was assessed using red dye staining. Analysis of cell attachment and cell proliferation revealed significantly higher osteoblast and PDL cell attachment on EMD-coated surfaces when compared with control and blood-coated surfaces. EMD also stimulated release of growth factors and cytokines, including bone morphogenetic protein 2 and transforming growth factor β1. Moreover, there were significantly higher mRNA levels of osteoblast differentiation markers, including COL1A1, ALP, and OC, in osteoblasts and PDL cells cultured on EMD-coated NBM particles. The present results suggest that 1) EMD enhances osteoblast and PDL cell attachment

  14. Anti-adhesive properties of fish tropomyosins

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk; Bernbom, Nete; Gram, Lone

    2008-01-01

    Aims: We have recently found that preconditioning of stainless steel surfaces with an aqueous fish muscle extract can significantly impede bacterial adhesion. The purpose of this study was to identify and characterize the primary components associated with this bacteria-repelling effect. Methods...... and Results: The anti-adhesive activity was assayed against Escherchia coli K-12, and bacterial adhesion was quantified by crystal violet staining and sonication methods. Proteolytic digestion, elution and fractionation experiments revealed that the anti-adhesive activity of the extract was linked...... to the formation of a proteinaceous conditioning film composed primarily of fish tropomyosins. These fibrous proteins formed a considerable anti-adhesive conditioning layer on and reduced bacterial adhesion to several different materials including polystyrene, vinyl plastic, stainless steel and glass. The protein...

  15. Electrochemical deposition of conductive and adhesive polypyrrole-dopamine films

    OpenAIRE

    Semin Kim; Jang, Lindy K.; Park, Hyun S.; Jae Young Lee

    2016-01-01

    Electrode surfaces have been widely modified with electrically conductive polymers, including polypyrrole (PPY), to improve the performance of electrodes. To utilize conductive polymers for electrode modification, strong adhesion between the polymer films and electrode substrates should be ensured with high electrical/electrochemical activities. In this study, PPY films were electrochemically polymerized on electrodes (e.g., indium tin oxide (ITO)) with dopamine as a bio-inspired adhesive mol...

  16. Test method to assess interface adhesion in composite bonding

    OpenAIRE

    2015-01-01

    This paper introduces a new type of peel tests dedicated to composite bonding: Composite Peel Tests. This test is inspired on the standard floating roller peel test widely used for metal bonding. The aim of this study is to investigate the potential of the Composite Peel Test to assess interface adhesion in composite bonded structures. To this end, peel tests were performed with nine different types of adhesives and at two environmental temperatures, room temperature and +80°C. The results we...

  17. Geophysics in INSPIRE

    Science.gov (United States)

    Sőrés, László

    2013-04-01

    INSPIRE is a European directive to harmonize spatial data in Europe. Its' aim is to establish a transparent, multidisciplinary network of environmental information by using international standards and OGC web services. Spatial data themes defined in the annex of the directive cover 34 domains that are closely bundled to environment and spatial information. According to the INSPIRE roadmap all data providers must setup discovery, viewing and download services and restructure data stores to provide spatial data as defined by the underlying specifications by 2014 December 1. More than 3000 institutions are going to be involved in the progress. During the data specification process geophysics as an inevitable source of geo information was introduced to Annex II Geology. Within the Geology theme Geophysics is divided into core and extended model. The core model contains specifications for legally binding data provisioning and is going to be part of the Implementation Rules of the INSPIRE directives. To minimize the work load of obligatory data transformations the scope of the core model is very limited and simple. It covers the most essential geophysical feature types that are relevant in economic and environmental context. To fully support the use cases identified by the stake holders the extended model was developed. It contains a wide range of spatial object types for geophysical measurements, processed and interpreted results, and wrapper classes to help data providers in using the Observation and Measurements (O&M) standard for geophysical data exchange. Instead of introducing the traditional concept of "geophysical methods" at a high structural level the data model classifies measurements and geophysical models based on their spatial characteristics. Measurements are classified as geophysical station (point), geophysical profile (curve) and geophysical swath (surface). Generic classes for processing results and interpretation models are curve model (1D), surface

  18. The focal adhesion-associated proteins DOCK5 and GIT2 comprise a rheostat in control of epithelial invasion

    DEFF Research Database (Denmark)

    Frank, S R; Köllmann, C P; van Lidth de Jeude, J F;

    2017-01-01

    DOCK proteins are guanine nucleotide exchange factors for Rac and Cdc42 GTPases. DOCK1 is the founding member of the family and acts downstream of integrins via the canonical Crk-p130Cas complex to activate Rac GTPases in numerous contexts. In contrast, DOCK5, which possesses the greatest...... with these cells. Collectively, our work identifies DOCK5 as a key regulator of epithelial invasion and metastasis, and demonstrates that suppression of DOCK5 by GIT2 represents a previously unappreciated mechanism for coordination of Rho and Rac GTPases.Oncogene advance online publication, 26 September 2016; doi...

  19. Diversification of the AlpB Outer Membrane Protein of Helicobacter pylori Affects Biofilm Formation and Cellular Adhesion.

    Science.gov (United States)

    Yonezawa, Hideo; Osaki, Takako; Fukutomi, Toshiyuki; Hanawa, Tomoko; Kurata, Satoshi; Zaman, Cynthia; Hojo, Fuhito; Kamiya, Shigeru

    2017-03-15

    Helicobacter pylori is one of the most common causes of bacterial infection in humans, and it forms biofilms on human gastric mucosal epithelium as well as on in vitro abiotic surfaces. Bacterial biofilm is critical not only for environmental survival but also for successful infection. We previously demonstrated that strain TK1402, which was isolated from a Japanese patient with duodenal and gastric ulcers, has high biofilm-forming ability in vitro relative to other strains. In addition, we showed that outer membrane vesicles (OMV) play an important role in biofilm formation. The aim of this study was to analyze which protein(s) in the OMV contributes to biofilm formation in TK1402. We obtained a spontaneous mutant strain derived from TK1402 lacking biofilm-forming ability. The protein profiles of the OMV were compared between this mutant strain and the wild type, and it was found that AlpB, an outer membrane protein in the OMV of the mutant strain, was markedly decreased compared to that of the wild type. Restoration of TK1402 alpB to the mutant strain fully recovered the ability to form biofilm. However, restoration with alpB from other strains demonstrated incomplete recovery of biofilm-forming ability. We therefore inferred that the variable region of AlpB (amino acid positions 121 to 146) was involved in TK1402 biofilm formation. In addition, diversification of the AlpB sequence was shown to affect the ability to adhere to AGS cells. These results demonstrate a new insight into the molecular mechanisms of host colonization by H. pyloriIMPORTANCE Bacterial biofilm is critical not only for environmental survival but also for successful infection. The mechanism of Helicobacter pylori adherence to host cells mediated by cell surface adhesins has been the focus of many studies, but little is known regarding factors involved in H. pylori biofilm formation. Our study demonstrated that AlpB plays an important role in biofilm formation and that this property depends

  20. Binding of complement inhibitor C4b-binding protein to a highly virulent Streptococcus pyogenes M1 strain is mediated by protein H and enhances adhesion to and invasion of endothelial cells.

    Science.gov (United States)

    Ermert, David; Weckel, Antonin; Agarwal, Vaibhav; Frick, Inga-Maria; Björck, Lars; Blom, Anna M

    2013-11-08

    Streptococcus pyogenes AP1, a strain of the highly virulent M1 serotype, uses exclusively protein H to bind the complement inhibitor C4b-binding protein (C4BP). We found a strong correlation between the ability of AP1 and its isogenic mutants lacking protein H to inhibit opsonization with complement C3b and binding of C4BP. C4BP bound to immobilized protein H or AP1 bacteria retained its cofactor activity for degradation of (125)I-C4b. Furthermore, C4b deposited from serum onto AP1 bacterial surfaces was processed into C4c/C4d fragments, which did not occur on strains unable to bind C4BP. Recombinant C4BP mutants, which (i) lack certain CCP domains or (ii) have mutations in single aa as well as (iii) mutants with additional aa between different CCP domains were used to determine that the binding is mainly mediated by a patch of positively charged amino acid residues at the interface of domains CCP1 and CCP2. Using recombinant protein H fragments, we narrowed down the binding site to the N-terminal domain A. With a peptide microarray, we identified one single 18-amino acid-long peptide comprising residues 92-109, which specifically bound C4BP. Biacore was used to determine KD = 6 × 10(-7) M between protein H and a single subunit of C4BP. C4BP binding also correlated with elevated levels of adhesion and invasion to endothelial cells. Taken together, we identified the molecular basis of C4BP-protein H interaction and found that it is not only important for decreased opsonization but also for invasion of endothelial cells by S. pyogenes.

  1. Gold Nanoparticle Aggregation as a Probe of Antifreeze (Glyco) Protein-Inspired Ice Recrystallization Inhibition and Identification of New IRI Active Macromolecules.

    Science.gov (United States)

    Mitchell, Daniel E; Congdon, Thomas; Rodger, Alison; Gibson, Matthew I

    2015-10-26

    Antifreeze (glyco)proteins are found in polar fish species and act to slow the rate of growth of ice crystals; a property known as ice recrystallization inhibition. The ability to slow ice growth is of huge technological importance especially in the cryopreservation of donor cells and tissue, but native antifreeze proteins are often not suitable, nor easily available. Therefore, the search for new materials that mimic this function is important, but currently limited by the low-throughout assays associated with the antifreeze properties. Here 30 nm gold nanoparticles are demonstrated to be useful colorimetric probes for ice recrystallization inhibition, giving a visible optical response and is compatible with 96 well plates for high-throughout studies. This method is faster, requires less infrastructure, and has easier interpretation than the currently used 'splat' methods. Using this method, a series of serum proteins were identified to have weak, but specific ice recrystallization inhibition activity, which was removed upon denaturation. It is hoped that high-throughput tools such as this will accelerate the discovery of new antifreeze mimics.

  2. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... in the formation of highly complex sessile communities, referred to as biofilms. Such microbial communities are often highly dynamic and heterogeneous in nature. Microbial biofilms are of great importance in a wide range of natural processes and industrial settings, from the commensal flora of the gastrointestinal...

  3. Syndecan-4 and focal adhesion function

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    2001-01-01

    Two groups have now reported the viability of mice that lack syndecan-4. These mice have wound healing/angiogenesis problems, and fibroblasts from these animals differ in adhesion and migration from normal. This is consistent with recent in vitro data indicating a need for signaling via syndecan-4...... for focal adhesion formation, and reports that overexpression of proteins that bind syndecan-4 can modify cell adhesion and migration....

  4. Type IV collagen is an activating ligand for the adhesion G protein-coupled receptor GPR126.

    Science.gov (United States)

    Paavola, Kevin J; Sidik, Harwin; Zuchero, J Bradley; Eckart, Michael; Talbot, William S

    2014-08-12

    GPR126 is an orphan heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptor (GPCR) that is essential for the development of diverse organs. We found that type IV collagen, a major constituent of the basement membrane, binds to Gpr126 and activates its signaling function. Type IV collagen stimulated the production of cyclic adenosine monophosphate in rodent Schwann cells, which require Gpr126 activity to differentiate, and in human embryonic kidney (HEK) 293 cells expressing exogenous Gpr126. Type IV collagen specifically bound to the extracellular amino-terminal region of Gpr126 containing the CUB (complement, Uegf, Bmp1) and pentraxin domains. Gpr126 derivatives lacking the entire amino-terminal region were constitutively active, suggesting that this region inhibits signaling and that ligand binding relieves this inhibition to stimulate receptor activity. A new zebrafish mutation that truncates Gpr126 after the CUB and pentraxin domains disrupted development of peripheral nerves and the inner ear. Thus, our findings identify type IV collagen as an activating ligand for GPR126, define its mechanism of activation, and highlight a previously unrecognized signaling function of type IV collagen in basement membranes.

  5. A Biologically Inspired Classifier

    CERN Document Server

    Bagnoli, Franco

    2007-01-01

    We present a method for measuring the distance among records based on the correlations of data stored in the corresponding database entries. The original method (F. Bagnoli, A. Berrones and F. Franci. Physica A 332 (2004) 509-518) was formulated in the context of opinion formation. The opinions expressed over a set of topic originate a ``knowledge network'' among individuals, where two individuals are nearer the more similar their expressed opinions are. Assuming that individuals' opinions are stored in a database, the authors show that it is possible to anticipate an opinion using the correlations in the database. This corresponds to approximating the overlap between the tastes of two individuals with the correlations of their expressed opinions. In this paper we extend this model to nonlinear matching functions, inspired by biological problems such as microarray (probe-sample pairing). We investigate numerically the error between the correlation and the overlap matrix for eight sequences of reference with r...

  6. A c-di-GMP effector system controls cell adhesion by inside-out signaling and surface protein cleavage.

    Directory of Open Access Journals (Sweden)

    Peter D Newell

    Full Text Available In Pseudomonas fluorescens Pf0-1 the availability of inorganic phosphate (Pi is an environmental signal that controls biofilm formation through a cyclic dimeric GMP (c-di-GMP signaling pathway. In low Pi conditions, a c-di-GMP phosphodiesterase (PDE RapA is expressed, depleting cellular c-di-GMP and causing the loss of a critical outer-membrane adhesin LapA from the cell surface. This response involves an inner membrane protein LapD, which binds c-di-GMP in the cytoplasm and exerts a periplasmic output promoting LapA maintenance on the cell surface. Here we report how LapD differentially controls maintenance and release of LapA: c-di-GMP binding to LapD promotes interaction with and inhibition of the periplasmic protease LapG, which targets the N-terminus of LapA. We identify conserved amino acids in LapA required for cleavage by LapG. Mutating these residues in chromosomal lapA inhibits LapG activity in vivo, leading to retention of the adhesin on the cell surface. Mutations with defined effects on LapD's ability to control LapA localization in vivo show concomitant effects on c-di-GMP-dependent LapG inhibition in vitro. To establish the physiological importance of the LapD-LapG effector system, we track cell attachment and LapA protein localization during Pi starvation. Under this condition, the LapA adhesin is released from the surface of cells and biofilms detach from the substratum. This response requires c-di-GMP depletion by RapA, signaling through LapD, and proteolytic cleavage of LapA by LapG. These data, in combination with the companion study by Navarro et al. presenting a structural analysis of LapD's signaling mechanism, give a detailed description of a complete c-di-GMP control circuit--from environmental signal to molecular output. They describe a novel paradigm in bacterial signal transduction: regulation of a periplasmic enzyme by an inner membrane signaling protein that binds a cytoplasmic second messenger.

  7. Theosophically Inspired Movements in Denmark

    DEFF Research Database (Denmark)

    Dybdal, René

    2016-01-01

    The theosophical movement has had a significant influence on the esoteric milieu in Denmark during the 20th Century. In this paper the inspiration on other Groups in Denmark is explored.......The theosophical movement has had a significant influence on the esoteric milieu in Denmark during the 20th Century. In this paper the inspiration on other Groups in Denmark is explored....

  8. Modification of Si(100) surface by the grafting of poly(ethylene glycol) for reduction in protein adsorption and platelet adhesion.

    Science.gov (United States)

    Zhang, F; Kang, E T; Neoh, K G; Wang, P; Tan, K L

    2001-09-05

    The modification of argon plasma-pretreated single-crystal Si(100) wafer surfaces via the UV-induced graft polymerization of poly(ethylene glycol) methacrylate (PEGMA) macromonomer (molecular weight approximately 340) for biomaterials applications was explored. The modified Si(100) surfaces were characterized by X-ray photoelectron spectroscopy and atomic force microscopy. Surface peroxide concentrations resulting from the argon plasma treatment and subsequent atmospheric exposure were determined by a coupling reaction with diphenylpicrylhydrazyl. The results suggested that a short plasma treatment time of 10 s and brief air exposure were sufficient for generating an optimum amount of peroxides and hydroperoxides for the subsequent UV-induced graft polymerization. The graft concentration of the PEGMA polymer increased with increasing PEGMA macromonomer concentration for the graft polymerization and with increasing UV graft polymerization time. The PEGMA graft-polymerized silicon surface with a high poly(ethylene glycol) graft concentration was very effective in preventing protein adsorption and platelet adhesion. The grafted PEGMA polymer layer on the Si(100) surface exhibited fairly good stability during storage in a buffer solution.

  9. Immobilization of poly(acrylamide) brushes onto poly(caprolactone) surface by combining ATRP and “click” chemistry: Synthesis, characterization and evaluation of protein adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Yuhao; Bian, Xinxiu; He, Liu; Cai, Mengtan; Xie, Xiaoxiong [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); Luo, Xianglin, E-mail: luoxl@scu.edu.cn [College of Polymer Science and Engineering, Sichuan University, Chengdu 610065 (China); State Key Laboratory of Polymer Material and Engineering, Sichuan University, Chengdu 610065 (China)

    2015-02-28

    Highlights: • Poly(caprolacone) (PCL) film surface was chemically modified by a novel method through combining ATRP and “click” chemistry. • Poly(acrylamide) (PAAm) of tailored chain length were synthesized and “clicked” onto PCL surface. • The modified PCL surface showed reduced BSA and Fg adsorption, and the protein resist ability in terms of chain length through its impact on grafting reaction and modified surface was investigated. - Abstract: Developments of poly(caprolactone) in blood-contacting applications are often restricted due to its intrinsic hydrophobicity. One common way to improve its hemocompatibility is to attach hydrophilic polymers. Here we developed a non-destructive method to graft hydrophilic poly(acrylamide) (PAAm) onto poly(caprolactone) (PCL) surface. In this strategy, azido-ended PCL with low molecular weights was synthesized and blended with PCL to create a surface with “clickable” property. Alkyne-ended poly(acrylamide)s with controlled chain lengths were then synthesized by atom transfer radical polymerization (ATRP), and finally were immobilized onto PCL surface by “click” reaction. The occurrence of immobilization was verified qualitatively by water contact angle measurement and quantitatively by X-ray photoelectron spectroscopy (XPS). The PAAm grafted surface exhibited fouling resistant properties, as demonstrated by reduced bovine serum albumin (BSA) and fibrinogen (Fg) adhesion.

  10. Epidemiological survey of Babesia gibsoni infection in dogs in Japan by enzyme-linked immunosorbent assay using B. gibsoni thrombospondin-related adhesive protein antigen.

    Science.gov (United States)

    Konishi, Kenji; Sakata, Yoshimi; Miyazaki, Naomi; Jia, Honglin; Goo, Youn-Kyoung; Xuan, Xuenan; Inokuma, Hisashi

    2008-08-17

    A nationwide epidemiological survey of Babesia gibsoni infection in non-fighting dogs was conducted using an improved ELISA with recombinant B. gibsoni thrombospondin-related adhesive protein (BgTRAP). A total of 1206 dogs from 27 prefectures were examined and 128 (10.6%) tested positive. In the eastern part of Japan, 39 dogs out of the 559 (7.0%) examined were positive, while 89 dogs out of 647 (13.8%) tested positive in the western part of Japan. Although the percentage of dogs that tested positive was significantly (p=0.0001) lower in the eastern part compared to the western part of Japan, overall these results indicate that B. gibsoni infection of dogs has a widespread geographic distribution throughout the country. A history of tick infestation was identified as a significant risk factor for B. gibsoni infection (p=0.0091), while sex (p=0.9411), age (p=0.0920) and breed (p=0.0549) of dogs were not statistically significant risk factors. These results indicate that tick infestation is the most dominant risk factor for B. gibsoni infection of non-fighting dogs in Japan and suggest that other B. gibsoni transmission routes, such as fighting and transplacental transmission, may be less important.

  11. A triad of lys12, lys41, arg78 spatial domain, a novel identified heparin binding site on tat protein, facilitates tat-driven cell adhesion.

    Directory of Open Access Journals (Sweden)

    Jing Ai

    Full Text Available Tat protein, released by HIV-infected cells, has a battery of important biological effects leading to distinct AIDS-associated pathologies. Cell surface heparan sulfate protoglycans (HSPGs have been accepted as endogenous Tat receptors, and the Tat basic domain has been identified as the heparin binding site. However, findings that deletion or substitution of the basic domain inhibits but does not completely eliminate Tat-heparin interactions suggest that the basic domain is not the sole Tat heparin binding site. In the current study, an approach integrating computational modeling, mutagenesis, biophysical and cell-based assays was used to elucidate a novel, high affinity heparin-binding site: a Lys12, Lys41, Arg78 (KKR spatial domain. This domain was also found to facilitate Tat-driven β1 integrin activation, producing subsequent SLK cell adhesion in an HSPG-dependent manner, but was not involved in Tat internalization. The identification of this new heparin binding site may foster further insight into the nature of Tat-heparin interactions and subsequent biological functions, facilitating the rational design of new therapeutics against Tat-mediated pathological events.

  12. Effects of Arg-Gly-Asp-modified elastin-like polypeptide on pseudoislet formation via up-regulation of cell adhesion molecules and extracellular matrix proteins.

    Science.gov (United States)

    Lee, Kyeong-Min; Jung, Gwon-Soo; Park, Jin-Kyu; Choi, Seong-Kyoon; Jeon, Won Bae

    2013-03-01

    Extracellular matrix (ECM) plays an important role in controlling the β-cell morphology, survival and insulin secretary functions. An RGD-modified elastin-like polypeptide (RGD-ELP), TGPG[VGRGD(VGVPG)(6)](20)WPC, has been reported previously as a bioactive matrix. In this study, to investigate whether RGD-ELP affects β-cell growth characteristics and insulin secretion, β-TC6 cells were cultured on the RGD-ELP coatings prepared via thermally induced phase transition. On RGD-ELP, β-TC6 cells clustered into an islet-like architecture with high cell viability. Throughout 7days' culture, the proliferation rate of the cells within a pseudoislet was similar to that of monolayer culture. Under high glucose (25mM), β-TC6 pseudoislets showed up-regulated insulin gene expression and exhibited glucose-stimulated insulin secretion. Importantly, the mRNA and protein abundances of cell adhesion molecules (CAM) E-cadherin and connexin-36 were much higher in pseudoislets than in monolayer cells. The siRNA-mediated inhibition of E-cadherin or connexin-36 expression severely limited pseudoislet formation. In addition, the mRNA levels of collagen types I and IV, fibronectin and laminin were significantly elevated in pseudoislets. The results suggest that RGD-ELP promotes pseudoislet formation via up-regulation of the CAM and ECM components. The functional roles of RGD-ELP are discussed in respect of its molecular composition.

  13. A triad of lys12, lys41, arg78 spatial domain, a novel identified heparin binding site on tat protein, facilitates tat-driven cell adhesion.

    Science.gov (United States)

    Ai, Jing; Xin, Xianliang; Zheng, Mingyue; Wang, Shuai; Peng, Shuying; Li, Jing; Wang, Limei; Jiang, Hualiang; Geng, Meiyu

    2008-01-01

    Tat protein, released by HIV-infected cells, has a battery of important biological effects leading to distinct AIDS-associated pathologies. Cell surface heparan sulfate protoglycans (HSPGs) have been accepted as endogenous Tat receptors, and the Tat basic domain has been identified as the heparin binding site. However, findings that deletion or substitution of the basic domain inhibits but does not completely eliminate Tat-heparin interactions suggest that the basic domain is not the sole Tat heparin binding site. In the current study, an approach integrating computational modeling, mutagenesis, biophysical and cell-based assays was used to elucidate a novel, high affinity heparin-binding site: a Lys12, Lys41, Arg78 (KKR) spatial domain. This domain was also found to facilitate Tat-driven β1 integrin activation, producing subsequent SLK cell adhesion in an HSPG-dependent manner, but was not involved in Tat internalization. The identification of this new heparin binding site may foster further insight into the nature of Tat-heparin interactions and subsequent biological functions, facilitating the rational design of new therapeutics against Tat-mediated pathological events.

  14. Leptospira Immunoglobulin-Like Protein B Interacts with the 20th Exon of Human Tropoelastin Contributing to Leptospiral Adhesion to Human Lung Cells

    Directory of Open Access Journals (Sweden)

    Ching-Lin Hsieh

    2017-05-01

    Full Text Available Leptospira immunoglobulin-like protein B (LigB, a surface adhesin, is capable of mediating the attachment of pathogenic leptospira to the host through interaction with various components of the extracellular matrix (ECM. Human tropoelastin (HTE, the building block of elastin, confers resilience and elasticity to lung, and other tissues. Previously identified Ig-like domains of LigB, including LigB4 and LigB12, bind to HTE, which is likely to promote Leptospira adhesion to lung tissue. However, the molecular mechanism that mediates the LigB-HTE interaction is unclear. In this study, the LigB-binding site on HTE was further pinpointed to a N-terminal region of the 20th exon of HTE (HTE20N. Alanine mutants of basic and aromatic residues on HTE20N significantly reduced binding to the LigB. Additionally, HTE-binding site was narrowed down to the first β-sheet of LigB12. On this binding surface, residues F1054, D1061, A1065, and D1066 were critical for the association with HTE. Most importantly, the recombinant HTE truncates could diminish the binding of LigB to human lung fibroblasts (WI-38 by 68%, and could block the association of LigA-expressing L. biflexa to lung cells by 61%. These findings should expand our understanding of leptospiral pathogenesis, particularly in pulmonary manifestations of leptospirosis.

  15. Surface modification of ultrahigh molecular weight polyethylene by the poly(ethylene glycol)-grafted method and its effect on the adsorption of proteins and the adhesion of blood platelets.

    Science.gov (United States)

    Xia, Bing; Xie, Meiju; Yang, Bangcheng

    2013-01-01

    With the help of a silane coupling agent, poly(ethylene glycol) (PEG), a well-biocompatable agent, was grafted onto the surface of ultrahigh molecular weight polyethylene (UHMWPE) by ultraviolet initiation. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis proved the success of PEG grafting. Water contact angle measurement showed that the modified UHMWPE was obviously improved in surface hydrophilicity and thermogravimetric analysis result showed that its thermostability did not decline even it was pretreated by strong acids. Then, the protein adsorption of the modified UHMWPE was investigated using three model proteins including bovine serum albumin, lysozyme, and fibrinogen. Rabbit blood was used to study the platelet adhesion on the surface of modified UHMWPE. The results indicated that the quantity of protein adsorption on the modified UHMWPE grafted PEG reduced apparently for all the model proteins while there was some specific differences or exceptions among them. It was ascribed to the changed surface chemical composition, surface hydrophilicity and surface topography after modification. The adhesive ability of blood platelets on the modified surface of UHMWPE decreased after PEG grafting. Owing to the improved resistance to fibrinogen adsorption and platelet adhesion, the surface modification might endow the UHWMPE surface better anticoagulation ability according to clotting mechanism.

  16. Truncating Mutations in the Adhesion G Protein-Coupled Receptor G2 Gene ADGRG2 Cause an X-Linked Congenital Bilateral Absence of Vas Deferens.

    Science.gov (United States)

    Patat, Olivier; Pagin, Adrien; Siegfried, Aurore; Mitchell, Valérie; Chassaing, Nicolas; Faguer, Stanislas; Monteil, Laetitia; Gaston, Véronique; Bujan, Louis; Courtade-Saïdi, Monique; Marcelli, François; Lalau, Guy; Rigot, Jean-Marc; Mieusset, Roger; Bieth, Eric

    2016-08-04

    In 80% of infertile men with obstructive azoospermia caused by a congenital bilateral absence of the vas deferens (CBAVD), mutations are identified in the cystic fibrosis transmembrane conductance regulator gene (CFTR). For the remaining 20%, the origin of the CBAVD is unknown. A large cohort of azoospermic men with CBAVD was retrospectively reassessed with more stringent selection criteria based on consistent clinical data, complete description of semen and reproductive excurrent ducts, extensive CFTR testing, and kidney ultrasound examination. To maximize the phenotypic prioritization, men with CBAVD and with unilateral renal agenesis were considered ineligible for the present study. We performed whole-exome sequencing on 12 CFTR-negative men with CBAVD and targeted sequencing on 14 additional individuals. We identified three protein-truncating hemizygous mutations, c.1545dupT (p.Glu516Ter), c.2845delT (p.Cys949AlafsTer81), and c.2002_2006delinsAGA (p.Leu668ArgfsTer21), in ADGRG2, encoding the epididymal- and efferent-ducts-specific adhesion G protein-coupled receptor G2, in four subjects, including two related individuals with X-linked transmission of their infertility. Previous studies have demonstrated that Adgrg2-knockout male mice develop obstructive infertility. Our study confirms the crucial role of ADGRG2 in human male fertility and brings new insight into congenital obstructive azoospermia pathogenesis. In men with CBAVD who are CFTR-negative, ADGRG2 testing could allow for appropriate genetic counseling with regard to the X-linked transmission of the molecular defect.

  17. Matriptase is required for the active form of hepatocyte growth factor induced Met, focal adhesion kinase and protein kinase B activation on neural stem/progenitor cell motility.

    Science.gov (United States)

    Fang, Jung-Da; Lee, Sheau-Ling

    2014-07-01

    Hepatocyte growth factor (HGF) is a chemoattractant and inducer for neural stem/progenitor (NS/P) cell migration. Although the type II transmembrane serine protease, matriptase (MTP) is an activator of the latent HGF, MTP is indispensable on NS/P cell motility induced by the active form of HGF. This suggests that MTP's action on NS/P cell motility involves mechanisms other than proteolytic activation of HGF. In the present study, we investigate the role of MTP in HGF-stimulated signaling events. Using specific inhibitors of phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) or focal adhesion kinase (FAK), we demonstrated that in NS/P cells HGF-activated c-Met induces PI3k-Akt signaling which then leads to FAK activation. This signaling pathway ultimately induces MMP2 expression and NS/P cell motility. Knocking down of MTP in NS/P cells with specific siRNA impaired HGF-stimulation of c-Met, Akt and FAK activation, blocked HGF-induced production of MMP2 and inhibited HGF-stimulated NS/P cell motility. MTP-knockdown NS/P cells cultured in the presence of recombinant protein of MTP protease domain or transfected with the full-length wild-type but not the protease-defected MTP restored HGF-responsive events in NS/P cells. In addition to functioning as HGF activator, our data revealed novel function of MTP on HGF-stimulated c-Met signaling activation.

  18. Enterococcal surface protein Esp is not essential for cell adhesion and intestinal colonization of Enterococcus faecium in mice

    Directory of Open Access Journals (Sweden)

    van Luit-Asbroek Miranda

    2009-01-01

    Full Text Available Abstract Background Enterococcus faecium has globally emerged as a cause of hospital-acquired infections with high colonization rates in hospitalized patients. The enterococcal surface protein Esp, identified as a potential virulence factor, is specifically linked to nosocomial clonal lineages that are genetically distinct from indigenous E. faecium strains. To investigate whether Esp facilitates bacterial adherence and intestinal colonization of E. faecium, we used human colorectal adenocarcinoma cells (Caco-2 cells and an experimental colonization model in mice. Results No differences in adherence to Caco-2 cells were found between an Esp expressing strain of E. faecium (E1162 and its isogenic Esp-deficient mutant (E1162Δesp. Mice, kept under ceftriaxone treatment, were inoculated orally with either E1162, E1162Δesp or both strains simultaneously. Both E1162 and E1162Δesp were able to colonize the murine intestines with high and comparable numbers. No differences were found in the contents of cecum and colon. Both E1162 and E1162Δesp were able to translocate to the mesenteric lymph nodes. Conclusion These results suggest that Esp is not essential for Caco-2 cell adherence and intestinal colonization or translocation of E. faecium in mice.

  19. Syndecans: synergistic activators of cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1998-01-01

    Cell-surface proteoglycans participate in cell adhesion, growth-factor signalling, lipase activity and anticoagulation. Until recently, only the roles of the glycosaminoglycan chains were investigated. Now, with molecular characterization of several core proteins, the roles of each individual...... molecules modulating integrin-based adhesion....

  20. Effects of Synthetic Neural Adhesion Molecule Mimetic Peptides and Related Proteins on the Cardiomyogenic Differentiation of Mouse Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Ruodan Xu

    2015-04-01

    Full Text Available Background/Aims: Pluripotent stem cells differentiating into cardiomyocyte-like cells in an appropriate cellular environment have attracted significant attention, given the potential use of such cells for regenerative medicine. However, the precise mechanisms of lineage specification of pluripotent stem cells are still largely to be explored. Identifying the role of various small synthetic peptides involved in cardiomyogenesis may provide new insights into pathways promoting cardiomyogenesis. Methods: In the present study, using a transgenic murine embryonic stem (ES cell lineage expressing enhanced green fluorescent protein (EGFP under the control of α-myosin heavy chain (α-MHC promoter (pαMHC-EGFP, we investigated the cardiomyogenic effects of 7 synthetic peptides (Betrofin3, FGLs, FGLL, hNgf_C2, EnkaminE, Plannexin and C3 on cardiac differentiation. The expression of several cardiac-specific markers was determined by RT-PCR whereas the structural and functional properties of derived cardiomyocytes were examined by immunofluorescence and electrophysiology, respectively. Results: The results revealed that Betrofin3, an agonist of brain derived neurotrophic factor (BDNF peptide exerted the most striking pro-cardiomyogenic effect on ES cells. We found that BDNF receptor, TrkB expression was up-regulated during differentiation. Treatment of differentiating cells with Betrofin3 between days 3 and 5 enhanced the expression of cardiac-specific markers and improved cardiomyocyte differentiation and functionality as revealed by genes regulation, flow cytometry and patch clamp analysis. Thus Betrofin3 may exert its cardiomyogenic effects on ES cells via TrkB receptor. Conclusion: Taken together, the results suggest that Betrofin3 modulates BDNF signaling with positive cardiomyogenic effect in stage and dose-dependent manner providing an effective strategy to increase ES cell-based generation of cardiomyocytes and offer a novel therapeutic approach to

  1. Protein phosphatase 2A plays a critical role in interleukin-2-induced beta 2-integrin dependent homotypic adhesion in human CD4+ T cell lines

    DEFF Research Database (Denmark)

    Brockdorff, J; Nielsen, M; Svejgaard, A

    1997-01-01

    Besides its function as a growth factor for T lymphocytes, interleukin 2 (IL-2) induces beta 2-integrin mediated adhesion, migration, and extravasation of T lymphocytes. It is, however, largely unknown how IL-2 receptors (IL-2R) are coupled to the beta 2-integrin adhesion pathway. Because IL-2 mo...... no inhibitory effect on cytokine induced adhesion at concentrations which strongly inhibited phosphatase activity. In conclusion, these data provide evidence that PP2A plays a critical role in IL-2-induced beta 2-integrin-dependent adhesion of human T cell lines.......Besides its function as a growth factor for T lymphocytes, interleukin 2 (IL-2) induces beta 2-integrin mediated adhesion, migration, and extravasation of T lymphocytes. It is, however, largely unknown how IL-2 receptors (IL-2R) are coupled to the beta 2-integrin adhesion pathway. Because IL-2...... modulates enzymatic activity and/or subcellular distribution of serine/threonine phosphatases 1 and 2A (PP1/PP2A) in T cells, we examined the role of these phosphatases in IL-2 induced homotypic adhesion in antigen specific human CD4+ T cell lines. We show that calyculin A, a potent inhibitor of PP1 and PP2...

  2. Cellular prion protein is required for neuritogenesis: fine-tuning of multiple signaling pathways involved in focal adhesions and actin cytoskeleton dynamics

    Directory of Open Access Journals (Sweden)

    Alleaume-Butaux A

    2013-07-01

    Full Text Available Aurélie Alleaume-Butaux,1,2 Caroline Dakowski,1,2 Mathéa Pietri,1,2 Sophie Mouillet-Richard,1,2 Jean-Marie Launay,3,4 Odile Kellermann,1,2 Benoit Schneider1,2 1INSERM, UMR-S 747, 2Paris Descartes University, Sorbonne Paris Cité, UMR-S 747, 3Public Hospital of Paris, Department of Biochemistry, INSERM UMR-S 942, Lariboisière Hospital, Paris, France; 4Pharma Research Department, Hoffmann La Roche Ltd, Basel, Switzerland Abstract: Neuritogenesis is a dynamic phenomenon associated with neuronal differentiation that allows a rather spherical neuronal stem cell to develop dendrites and axon, a prerequisite for the integration and transmission of signals. The acquisition of neuronal polarity occurs in three steps: (1 neurite sprouting, which consists of the formation of buds emerging from the postmitotic neuronal soma; (2 neurite outgrowth, which represents the conversion of buds into neurites, their elongation and evolution into axon or dendrites; and (3 the stability and plasticity of neuronal polarity. In neuronal stem cells, remodeling and activation of focal adhesions (FAs associated with deep modifications of the actin cytoskeleton is a prerequisite for neurite sprouting and subsequent neurite outgrowth. A multiple set of growth factors and interactors located in the extracellular matrix and the plasma membrane orchestrate neuritogenesis by acting on intracellular signaling effectors, notably small G proteins such as RhoA, Rac, and Cdc42, which are involved in actin turnover and the dynamics of FAs. The cellular prion protein (PrPC, a glycosylphosphatidylinositol (GPI-anchored membrane protein mainly known for its role in a group of fatal neurodegenerative diseases, has emerged as a central player in neuritogenesis. Here, we review the contribution of PrPC to neuronal polarization and detail the current knowledge on the signaling pathways fine-tuned by PrPC to promote neurite sprouting, outgrowth, and maintenance. We emphasize that Pr

  3. Advanced adhesives in electronics

    CERN Document Server

    Bailey, C

    2011-01-01

    Adhesives are widely used in the manufacture of electronic devices to act as passive and active components. Recently there has been considerable interest in the use of conductive adhesives. This book reviews key types of conductive adhesives, processing methods, properties and the way they can be modelled as well as potential applications.$bAdhesives for electronic applications serve important functional and structural purposes in electronic components and packaging, and have developed significantly over the last few decades. Advanced adhesives in electronics reviews recent developments in adhesive joining technology, processing and properties. The book opens with an introduction to adhesive joining technology for electronics. Part one goes on to cover different types of adhesive used in electronic systems, including thermally conductive adhesives, isotropic and anisotropic conductive adhesives and underfill adhesives for flip-chip applications. Part two focuses on the properties and processing of electronic ...

  4. 大豆蛋白胶麻杆刨花板制备工艺的研究%Study on preparation of soy protein adhesive-based hemp stalk particle board

    Institute of Scientific and Technical Information of China (English)

    庞媛; 杨光; 杨波; 翟艳

    2011-01-01

    为了开发环境友好型刨花板,探讨利用大豆蛋白胶黏剂压制麻杆刨花板的制备工艺,分析热压温度、热压时间、施胶量和密度对麻杆刨花板性能的影响.结果表明,大豆蛋白胶可以用于麻杆刨花板的制造,其最佳工艺参数为:热压温度180℃,热压时间25 min,施胶量18%,密度0.80 g/cm3.在此条件下,压制的板材的性能超过GB/T 4897.4-2003的要求.%Preparation of hemp stalk particle board derived from soy protein-based adhesive were investigated and the effects of hot pressing temperature, hot pressing time, soy protein-based adhesive content, and density of hemp particle on the particle board physical and mechanical properties were analyzed. The results showed that soy protein-based adhesive can be used in hemp stalk particle board production and the optimal parameters were hot pressing temperature 180℃ , hot pressing time 25 min, soy protein-based adhesive content 18% ,density of hemp particle board 0. 80 g/cm3. Under above conditions,the particle-board has mechanical properties exceeding the Chinese National GB/T 4897. 4-2003 standard requirements.

  5. Mechanics ofadhesion and contact self-cleaning of bio-inspired microfiberadhesives

    Science.gov (United States)

    Abusomwan, Uyiosa Anthony

    The remarkable attachment system of geckos has inspired the development of dry microfiber adhesives through the last two decades. Some of the notable characteristics of gecko-inspired fibrillar adhesives include: strong, directional, and controllable adhesion to smooth and rough surfaces in air, vacuum, and under water; ability to maintain strong adhesion during repeated use; anti-fouling and self-cleaning after contamination. Given these outstanding qualities, fibrillar adhesives promise an extensive range of use in industrial, robotic, manufacturing, medical, and consumer products. Significant advancements have been made in the design of geckoinspired microfiber adhesives with the characteristic properties listed above, with the exception of the anti-fouling and self-cleaning features. The self-cleaning mechanism of the gecko's adhesion system plays an important role to its ability to remain sticky in various environments. Similarly, enabling self-cleaning capability for synthetic microfiber adhesives will lead to robust performance in various areas of application. Presently, the practical use of fibrillar adhesives is restricted mainly to clean environments, where they are free from contaminants. The goal of this thesis is to conduct a detailed study of the mechanisms and mechanics of contact-based self-cleaning of gecko-inspired microfiber adhesives. This work focuses on contact self-cleaning mechanisms, as a more practical approach to cleaning. Previous studies on the cleaning of microfiber adhesives have mostly focused on mechanisms that involve complete removal of the contaminants from the adhesive. In this thesis, a second cleaning process is proposed whereby particles are removed from the tip of the microfibers and embedded between adjacent microfibers or in grooves patterned onto the adhesive, where they are no longer detrimental to the performance of the adhesive. In this work, a model of adhesion for microfiber adhesives that take the deformation of the

  6. Holography inspired stringy hadrons

    Science.gov (United States)

    Sonnenschein, Jacob

    2017-01-01

    Holography inspired stringy hadrons (HISH) is a set of models that describe hadrons: mesons, baryons and glueballs as strings in flat four dimensional space-time. The models are based on a "map" from stringy hadrons of holographic confining backgrounds. In this note we review the "derivation" of the models. We start with a brief reminder of the passage from the AdS5 ×S5 string theory to certain flavored confining holographic models. We then describe the string configurations in holographic backgrounds that correspond to a Wilson line, a meson, a baryon and a glueball. The key ingredients of the four dimensional picture of hadrons are the "string endpoint mass" and the "baryonic string vertex". We determine the classical trajectories of the HISH. We review the current understanding of the quantization of the hadronic strings. We end with a summary of the comparison of the outcome of the HISH models with the PDG data about mesons and baryons. We extract the values of the tension, masses and intercepts from best fits, write down certain predictions for higher excited hadrons and present attempts to identify glueballs.

  7. [Medicine inspired by poverty].

    Science.gov (United States)

    Barnard, H

    2000-05-13

    Since his arrival in Egypt in 1994 the author joined a number of archaeological expeditions as a surveyor and part-time physician. During this latter activity he came into contact with the beliefs and practices of the local workmen and those of the Ababda Bedouin in particular. Living a harsh life in the southern part of the Egyptian Eastern Desert, their medicine seems to be inspired by poverty. Widely used for all internal disorders are 'kaya bil-naar': oval scars made with red-hot metal instruments. Another, less common, form of scarification is 'mi'ah-hed'asher', three parallel lines carved deeply into the cheek of the patient. 'Muhawy' is the bite of a snake into the earlobe of the patient, to prevent snake-bites. Another prophylactic is the 'higab', a small leather pouch containing a magical object or text. Therapies for less serious disorders include the use of herbs, spices and foodstuffs, often prepared in special ways. Externally, car fuel and axle grease are widely used. With the development of the Red Sea coast for tourism, the life of the Ababda Bedouin will change fundamentally. The above practices are likely to be replaced by Western medicine, probably a change for the better for these people.

  8. Inspiration, anyone? (Editorial

    Directory of Open Access Journals (Sweden)

    Lindsay Glynn

    2006-09-01

    Full Text Available I have to admit that writing an editorial for this issue was a struggle. Trying to sit down and write when the sun was shining outside and most of my colleagues were on vacation was, to say the least, difficult. Add to that research projects and conferences…let’s just say that I found myself less than inspired. A pitiful plea for ideas to a colleague resulted in the reintroduction to a few recent evidence based papers and resources which inspired further searching and reading. Though I generally find myself surrounded (more like buried in research papers and EBLIP literature, somehow I had missed the great strides that have been made of late in the world of evidence based library and information practice. I realize now that I am inspired by the researchers, authors and innovators who are putting EBLIP on the proverbial map. My biggest beef with library literature in general has been the plethora of articles highlighting what we should be doing. Take a close look at the evidence based practitioners in the information professions: these are some of the people who are actively practicing what has been preached for the past few years. Take, for example, the about‐to‐be released Libraries using Evidence Toolkit by Northern Sydney Central Coast Health and The University of Newcastle, Australia (see their announcement in this issue. An impressive advisory group is responsible for maintaining the currency and relevancy of the site as well as promoting the site and acting as a steering committee for related projects. This group is certainly doing more than “talking the talk”: they took their experience at the 3rd International Evidence Based Librarianship Conference and did something with the information they obtained by implementing solutions that worked in their environment. The result? The creation of a collection of tools for all of us to use. This toolkit is just what EBLIP needs: a portal to resources aimed at supporting the information

  9. Inspired by CERN

    CERN Multimedia

    2004-01-01

    Art students inspired by CERN will be returning to show their work 9 to 16 October in Building 500, outside the Auditorium. Seventeen art students from around Europe visited CERN last January for a week of introductions to particle physics and astrophysics, and discussions with CERN scientists about their projects. A CERN scientist "adopted"each artist so they could ask questions during and after the visit. Now the seeds planted during their visit have come to fruition in a show using many media and exploring varied concepts, such as how people experience the online world, the sheer scale of CERN's equipment, and the abstractness of the entities scientists are looking for. "The work is so varied, people are going to love some pieces and detest others," says Andrew Charalambous, the project coordinator from University College London who is also curating the exhibition. "It's contemporary modern art, and that's sometimes difficult to take in." For more information on this thought-provoking show, see: htt...

  10. Combining Bio-inspired Sensing with Bio-inspired Locomotion

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model that modula......In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model...... that modulates the parameters of the locomotor central pattern generators. We present phonotactic performance results of the simulated lizard-salamander hybrid robot....

  11. Combining Bio-inspired Sensing with Bio-inspired Locomotion

    DEFF Research Database (Denmark)

    Shaikh, Danish; Hallam, John; Christensen-Dalsgaard, Jakob

    In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model that modula......In this paper we present a preliminary Braitenberg vehicle–like approach to combine bio-inspired audition with bio-inspired quadruped locomotion in simulation. Locomotion gaits of the salamander–like robot Salamandra robotica are modified by a lizard’s peripheral auditory system model...... that modulates the parameters of the locomotor central pattern generators. We present phonotactic performance results of the simulated lizard-salamander hybrid robot....

  12. Extraction and identification of adhesion-associated S-layer proteins of L. casei LC2W%干酪乳杆菌LC2W表面黏附相关蛋白的提取与鉴定

    Institute of Scientific and Technical Information of China (English)

    周方方; 吴正钧; 王荫榆; 郭本恒

    2009-01-01

    Objective To extract and identify the S-layer proteins of Lactobacillus casei LC2W that associates with adhesion and preliminarily study the mechemism of LC2W adhesion on MKN-45 cells. Method S-layer proteins were extracted by LiCl and isolated by Sephadex G-75. Then the adhesion assay, electron microscopic observation and SDS-PAGE were used to identify the S-layer protein associated with adhesion. Result After the treatment of LiCl, electron microscopic observation showed that the surface of LC2W was rough but the cells were still in their integrity. The ability of adhesion to MKN-45 cells was significantly reduced. S-layer proteins of LC2W were composed of three proteins with molecular weights of 41.6, 63.5 and 66.2 kDa, respectively. After the isolation by Sephadex G-75, it was found that the 41.6 kDa fraction could significantly improve the adhesion of LC2W treated by LiCl and the adhesive ability of the treated cells amounted to the level of the normal ones. Conclusion The S-layer proteins were involved in the adhesion of LC2W on MKN-45 and the active component was the protein with molecular weight of 41.6 kDa.%目的 提取和鉴定干酪乳杆菌LC2W表面黏附相关蛋白,初步探索LC2W对胃癌细胞MKN-45细胞的黏附机制.方法 LiCl处理、Sephadex G-75柱层析分离提取LC2W的表面蛋白,用黏附试验、电镜观察和SDS-PAGE电泳进行黏附相关蛋白的鉴定.结果 LC2W经LiCl处理后,扫描电镜结果发现菌体表面粗糙但仍完整,黏附试验表明其对MKN-45细胞的黏附能力显著降低.提取到的表面蛋白的分子量分别为41.6、63.5、66.2 kDa.粗