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Cellular Adhesion (cellular + adhesion)
Terms modified by Cellular Adhesion Selected AbstractsPhenolic Hydroxy Groups Incorporated for the Peroxidase-Catalyzed Gelation of a Carboxymethylcellulose Support: Cellular Adhesion and ProliferationMACROMOLECULAR BIOSCIENCE, Issue 3 2009Yuko Ogushi Abstract The effect of Ph-OH group content on gelation time, mechanical properties, hydrophobicity, and cellular adhesiveness of hydrogels produced from carboxymethylcellulose derivatives is investigated. A higher Ph-OH group content induces faster gelation and yields more brittle and hydrophobic gels. After 4 h of seeding, a larger number of L929 fibroblasts adhere to the hydrogel of the CMC-Ph that contains 15.4 Ph-OH groups per 100 repeat units of uronic acid (97% adhesion rate) than to the gel of CMC-Ph with only 8.4 Ph-OH groups (62% adhesion rate). The results demonstrate that controlling the Ph-OH group content is an effective and useful way to control cellular adhesion and proliferation on the hydrogels, as well as gelation time and mechanical properties of the gels. [source] Cellular Adhesion, Proliferation and Viability on Conducting Polymer SubstratesMACROMOLECULAR BIOSCIENCE, Issue 12 2008Luis J. del Valle Abstract This work reports a comprehensive study about cell adhesion and proliferation on the surface of different electroactive substrates formed by ,-conjugated polymers. Biological assays were performed considering four different cellular lines: two epithelial and two fibroblasts. On the other hand, the electroactivity of the three conducting systems was determined in physiological conditions. Results indicate that the three substrates behave as a cellular matrix, even though compatibility with cells is larger for PPy and the 3-layered system. Furthermore, the three polymeric systems are electro-compatible with the cellular monolayers. [source] Development of Live Cell Chips to Monitor Cell Differentiation ProcessesENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 1 2008C. Maercker Abstract A big demand exists for high-throughput functional in vitro assays which can measure cellular phenotypes by molecular methods and therefore improve the resources of primary cells for cell therapy, tissue engineering and high-content screenings in drug development. This approach focuses on cellular adhesion which is an important differentiation process during homing of stem cells. Moreover, it is a promising method especially for adherent cells which are not accessible by classical cell sorting methods. The chip design includes a housing with electrodes to measure electric field densities and impedance, respectively. Moreover, specific coatings of the wells permit a perfect growth of the selected cell types. In parallel, protein biomarkers can be followed by light microscopy. So far, experiments have been started to discriminate between different cell densities and cell types. In addition, after stimulating human cardiac fibroblasts and human umbilical vein endothelial cells, concentrations of proteins involved in adhesion had been increased, and proteins were translocated within the cells. In ongoing experiments, different human cell lines and fibroblastoid mesenchymal stem cells isolated from fat tissue, umbilical cord, or bone marrow are tested in the chip. To optimize the adhesion conditions, the surfaces within the vials of the chip were specifically activated. Microscopy was adjusted to be able to measure cellular morphology in parallel. This concept allows to identify the behavior of mesenchymal stem cells, which cannot be described so far by standard biomarkers. In addition, simulation of the homing process of the cells within its stem cell niche in an in vitro assay is a promising setup for large-scale gain-of-function or loss-of-function screenings in functional genomics as well as for generating precursor cells relevant for the therapy of various diseases. [source] Therapeutic approaches to epileptogenesis,Hope on the horizonEPILEPSIA, Issue 2010Asla Pitkänen Summary Prevention of epileptogenesis is an unmet need in medicine. During the last 3 years, however, several preclinical studies have demonstrated remarkable favorable effects of novel treatments on genetic and acquired epileptogenesis. These include the use of immunosuppressants and treatments that modify cellular adhesion, proliferation, and/or plasticity. In addition, the use of antiepileptic drugs in rats with genetic epilepsy or proconvulsants in acquired epilepsy models has provided somewhat unexpected favorable effects. This review summarizes these studies, and introduces some caveats when interpreting the data. In particular, the effect of genetic background, the severity of epileptogenic insult, the method and duration of seizure monitoring, and size of animal population are discussed. Furthermore, a novel scheme for defining epileptogenesis-related terms is presented. [source] Identification of membrane-bound serine proteinase matriptase as processing enzyme of insulin-like growth factor binding protein-related protein-1 (IGFBP-rP1/angiomodulin/mac25)FEBS JOURNAL, Issue 3 2006Sanjida Ahmed Insulin-like growth factor (IGF) binding protein-related protein-1 (IGFBP-rP1) modulates cellular adhesion and growth in an IGF/insulin-dependent or independent manner. It also shows tumor-suppressive activity in vivo. We recently found that a single-chain IGFB-rP1 is proteolytically cleaved to a two-chain form by a trypsin-like, endogenous serine proteinase, changing its biological activities. In this study, we attempted to identify the IGFBP-rP1-processing enzyme. Of nine human cell lines tested, seven cell lines secreted IGFBP-rP1 at high levels, and two of them, ovarian clear cell adenocarcinoma (OVISE) and gastric carcinoma (MKN-45), highly produced the cleaved IGFBP-rP1. Serine proteinase inhibitors effectively blocked the IGFBP-rP1 cleavage in the OVISE cell culture. The conditioned medium of OVISE cells did not cleave purified IGFBP-rP1, but their membrane fraction had an IGFBP-rP1-cleaving activity. The membrane fraction contained an 80-kDa gelatinolytic enzyme, which was identified as the membrane-type serine proteinase matriptase (MT-SP1) by immunoblotting. When the membrane fraction was separated by SDS/PAGE, the IGFBP-rP1-cleaving activity comigrated with matriptase. A soluble form of matriptase purified in an inhibitor-free form efficiently cleaved IGFBP-rP1 at the same site as that found in a naturally cleaved IGFBP-rP1. Furthermore, small interfering RNAs for matriptase efficiently blocked both the matriptase expression and the cleavage of IGBP-rP1 in OVISE cells. These results demonstrate that IGFBP-rP1 is processed to the two-chain form by matriptase on the cell surface. [source] Lef-1 isoforms regulate different target genes and reduce cellular adhesionINTERNATIONAL JOURNAL OF CANCER, Issue 5 2010Sarah Jesse Abstract The lymphoid enhancer factor 1 (Lef-1) belongs to the nuclear transducers of canonical Wnt-signalling in embryogenesis and cancer. Lef-1 acts, in cooperation with ,-catenin, as a context-dependent transcriptional activator or repressor, thereby influencing multiple cellular functions such as proliferation, differentiation and migration. Here we report that an increased Lef-1 expression in human pancreatic cancer correlates with advanced tumour stages. In pancreatic tumours, two different transcripts of Lef-1 have been detected in various stages, as demonstrated by RT-PCR analysis. One transcript was identified as the full length Lef-1 (Lef-1 FL), whereas the second, shorter transcript lacked exon VI (Lef-1 ,exon VI) compared to the published sequence. Comparative analysis of these two Lef-1 variants revealed that they exhibit different cellular effects after transient expression in pancreatic carcinoma cells. Forced expression of Lef-1 ,exon VI inhibited E-cadherin expression in a ,-catenin-independent way. Increased amounts of Lef-1 ,exon VI resulted in reduced cellular aggregation and increased cell migration. Expression of Lef-1 FL, but not the newly identified Lef-1 ,exon VI, induced the expression of the cell cycle regulating proteins c-myc and cyclin D1 in cooperation with ,-catenin and it enhanced cell proliferation. Our findings indicate that expression of alternatively spliced Lef-1 isoforms is involved in the determination of proliferative or migratory characteristics of pancreatic carcinoma cells. [source] Gellan,adipic acid blends crosslinked by means of a dehydrothermal treatmentJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010Niccoletta Barbani Abstract Blends of gellan gum (GE) and adipic acid (ADA), at various ratios, were manufactured in the form of films by casting from aqueous solutions and crosslinked by a dehydrothermal treatment (DHT). The materials, before and after DHT, were characterized by both physicochemical tests and cellular adhesion and growth on the film surfaces. The total reflection and spotlight Fourier transform infrared (FTIR) spectroscopy and optical and scanning electron microscopy showed the presence of both GE-rich and ADA-rich regions and the formation of ester groups after DHT. Differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analysis (DMA) showed that the crosslinking by DHT made the materials more thermally stable. The swelling in water, which diminished in the films subjected to DHT, confirmed that the crosslinking enhanced the whole stability of the material. DMA also showed that the behavior of the GE,ADA blends was quite similar to that of some living tissues, such as the skin. The cell cultures indicated that the materials, especially that with a 6 : 10 ADA-to-GE ratio, were very able to promote cellular adhesion and proliferation. In conclusion, the GE,ADA crosslinked blends appeared very suitable for a use as biomaterials; in particular, the cell cultures indicated that they might be useful as scaffolds for tissue reconstruction. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source] Effects of chitosan solution concentration and incorporation of chitin and glycerol on dense chitosan membrane propertiesJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2007Paula Rulf Marreco Dallan Abstract The aim of this work was to perform a systematic study about the effects induced by chitosan solution concentration and by chitin or glycerol incorporation on dense chitosan membranes with potential use as burn dressings. The membrane properties analyzed were total raw material cost, thickness, morphology, swelling ratio, tensile strength, percentage of strain at break, crystallinity, in vitro enzymatic degradation with lysozyme, and in vitro Vero cells adhesion. While the use of the most concentrated chitosan solution (2.5% w/w) increased membrane cost, it also improved the biomaterial mechanical resistance and ductility, as well as reduced membrane degradation when exposed for 2 months to lysozyme. The remaining evaluated properties were not affected by initial chitosan solution concentration. Chitin incorporation, on the other hand, reduced the membranes cost, swelling ratio, mechanical properties, and crystallinity, resulting in thicker biomaterials with irregular surface more easily degradable when exposed to lysozyme. Glycerol incorporation also reduced the membranes cost and crystallinity and increased membranes degradability after exposure to lysozyme. Strong Vero cells adhesion was not observed in any of the tested membrane formulations. The overall results indicate that the majority of the prepared membranes meet the performance requirements of temporary nonbiodegradable burn dressings (e.g. adequate values of mechanical resistance and ductility, low values of in vitro cellular adhesion on their surfaces, low extent of degradation when exposed to lysozyme solution, and high stability in aqueous solutions). © 2006 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007 [source] GDF-5/7 and bFGF activate integrin ,2-mediated cellular migration in rabbit ligament fibroblastsJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2010Hirokazu Date Abstract Cellular activities responding to growth factors are important in ligament healing. The anterior cruciate ligament (ACL) has poor healing potential compared to the medial collateral ligament (MCL). To assess the differences, we investigated the proliferation, migration, adhesion, and matrix synthesis responding to growth factors in rabbit ACL and MCL fibroblasts. ACL cell proliferation to basic fibroblast growth factor (bFGF), bone morphogenetic protein-2, growth and differentiation factor (GDF)-5, and GDF-7 treatment was similar to that of MCL cells. GDF-5 enhanced Col1a1 expression in ACL and MCL fibroblasts up to 4.7- and 17-fold levels of control, respectively. MCL fibroblasts showed stronger migration activities in response to bFGF and GDF-5 than ACL cells. GDF-5/7 and bFGF also changed the stress fiber formation and cellular adhesion by modulating the distribution of integrin ,2. Functional blocking analyses using anti-integrin ,2 antibodies revealed that cellular migration responding to growth factors depended on the integrin ,2-mediated adhesion on type I collagen. The expression of integrin ,2 was also increased by growth factors in both cells. Our results demonstrate that GDF-5/7 and bFGF stimulate cellular migration by modulating integrin ,2 expression and integrin ,2-dependent adhesion, especially in MCL fibroblasts. These findings suggest that the different healing potential between ACL and MCL may be caused by different cellular behavior in the integrin ,2-mediated cellular migration in response to growth factors. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:225,231, 2010 [source] Phenolic Hydroxy Groups Incorporated for the Peroxidase-Catalyzed Gelation of a Carboxymethylcellulose Support: Cellular Adhesion and ProliferationMACROMOLECULAR BIOSCIENCE, Issue 3 2009Yuko Ogushi Abstract The effect of Ph-OH group content on gelation time, mechanical properties, hydrophobicity, and cellular adhesiveness of hydrogels produced from carboxymethylcellulose derivatives is investigated. A higher Ph-OH group content induces faster gelation and yields more brittle and hydrophobic gels. After 4 h of seeding, a larger number of L929 fibroblasts adhere to the hydrogel of the CMC-Ph that contains 15.4 Ph-OH groups per 100 repeat units of uronic acid (97% adhesion rate) than to the gel of CMC-Ph with only 8.4 Ph-OH groups (62% adhesion rate). The results demonstrate that controlling the Ph-OH group content is an effective and useful way to control cellular adhesion and proliferation on the hydrogels, as well as gelation time and mechanical properties of the gels. [source] Effect of crosslinking on the elasticity of polyelectrolyte multilayer films measured by colloidal probe AFMMICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2006Grégory Francius Abstract A homemade colloidal probe atomic force microscope was used to perform nanoindentation with a spherical probe of 5 ,m in diameter, at different approach velocities in order to extract the Young's modulus, E0, of poly(L-lysine)/hyaluronan (PLL/HA) films. This parameter is of prime importance to control cellular adhesion. The films were either kept in their native form or cross-linked with a mixture of 1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide (EDC) and N -hydrosulfosuccinimide (sulfo-NHS), where the EDC concentration was varied from 1 up to 100 mg mL,1 (approximately from 5 to 500 mM). A model based on Hertz mechanics was used to account for the interactions between film and probe. It is shown that the Young's modulus varies with the approach velocity for the native (PLL/HA) films, whereas for cross-linked ones, E0 is independent from the velocity over the whole range investigated. It is found that for native films, E0 takes a value of 3 kPa at low approach velocities, a velocity domain that should be relevant in cellular adhesion processes. The Young's modulus increases with the EDC concentration used to cross-link the films and levels off at a value of about 400 kPa for EDC concentrations exceeding 40 mg mL,1. Thus, it is possible by crosslinking PLL/HA films to control their elastic properties with the aim to alter their behavior as to the cellular adhesion. Microsc. Res. Tech. 69:84,92, 2006. © 2006 Wiley-Liss, Inc. [source] Glycoproteomics and glycomics investigation of membrane N -glycosylproteins from human colon carcinoma cellsPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 16 2008Anne-Sophie Vercoutter-Edouart Dr. Abstract Aberrant glycosylation of proteins is known to profoundly affect cellular adhesion or motility of tumoral cells. In this study, we used HT-29 human colon epithelial cancer cells as a cellular model of cancer progression, as they can either proliferate or differentiate into enterocyte phenotype. A glycoproteomic approach based on Con A lectin-affinity chromatography, SDS-PAGE and MS analysis, allowed the identification of membrane N -glycoproteins from Triton X-100-solubilized proteins from membrane preparation. Among them, 65% were membrane proteins, and 45% were known to be N -glycosylated, such as , chains integrin and dipeptidyl isomerase IV. By lectin-blot analysis, significant changes of ,-2,3- and ,-2,6-sialylation of membrane glycoproteins were observed between proliferating and differentiated HT-29 cells. From these results, nano-LC-MS/MS analysis of the tryptic digests of the corresponding bands was performed and led to the identification of several transmembrane glycoproteins, like members of the solute carrier family and adhesion proteins. Finally, we compared N -glycans profiles and monosaccharide composition of proliferating and enterocyte-like HT-29 cells using MALDI-MS and GC-MS analyses of permethylated derivatives. This glycomic approach allowed to underscore significant changes in N -glycans structure, in particular the expression of atypical N -acetylglucosamine (GlcNAc)-ended N -glycans in enterocyte-like HT-29 cells. [source] Accommodation in ABO-Incompatible Kidney Allografts, a Novel Mechanism of Self-Protection Against Antibody-Mediated InjuryAMERICAN JOURNAL OF TRANSPLANTATION, Issue 8 2003Walter D. Park To elucidate the mechanism of self-protection against anti-donor blood-group antibody known as accommodation, we studied 16 human ABO-incompatible living-donor kidney transplant recipients at 3 and 12 months post transplantation. Both circulating anti-blood-group antibody and the target blood-group antigen in the graft were demonstrable in all patients after transplantation. Thirteen of 16 grafts had normal renal function and histology, while three grafts with prior humoral rejection demonstrated significant glomerulopathy and thus did not meet the criterion for accommodation. Using microarrays, we compared five 1-year protocol ABO-compatible renal graft biopsies to four accommodated ABO-incompatible graft biopsies. Significant alterations in gene expression in 440 probe sets, including SMADs, protein tyrosine kinases, TNF-, and Mucin 1 were identified. We verified these changes in gene expression using RT-PCR and immunohistochemistry. Heme oxygenase-1, Bcl-2 and Bcl-xl were not increased in ABO-incompatible grafts at any time-point. We conclude that accommodation is always present in well-functioning, long-surviving ABO-incompatible kidney transplants. This self-protection against antibody-mediated damage may involve several novel mechanisms including the disruption of normal signal transduction, attenuation of cellular adhesion and the prevention of apoptosis. [source] Light up-regulated on B lymphocytes and monocytes in rheumatoid arthritis mediates cellular adhesion and metalloproteinase production by synoviocytesARTHRITIS & RHEUMATISM, Issue 4 2007Young Mo Kang Objective To study the expression of LIGHT (tumor necrosis factor superfamily 14) and herpesvirus entry mediator (HVEM; tumor necrosis factor receptor superfamily 14) in rheumatoid arthritis (RA) and to determine the regulatory role of LIGHT on the effector functions of fibroblast-like synoviocytes (FLS). Methods The expression of LIGHT and HVEM was assessed by immunohistochemical staining of synovial tissue and by flow cytometric analysis of mononuclear cells. The presence of HVEM and lymphotoxin , receptor was measured by reverse transcriptase,polymerase chain reaction and by flow cytometry. The regulation of effector molecules, including matrix metalloproteinases (MMPs) and adhesion molecules, was evaluated. The adhesiveness of FLS was determined by adhesion assay. Results HVEM was detected in most cell types within rheumatoid synovial tissue, while only a few cells were positive for LIGHT. In RA patients, LIGHT expression was significantly up-regulated only in CD20+ B cells and monocytes, whereas the mean fluorescence intensity of HVEM was down-regulated in mononuclear cells. The stimulation of FLS with LIGHT resulted in the production of MMPs and the expression of adhesion molecules, which were efficiently inhibited by dexamethasone. LIGHT-mediated up-regulation of MMPs and intercellular adhesion molecule 1 was blocked by inhibitors of NF-,B and JNK, whereas up-regulation of vascular cell adhesion molecule 1 was blocked by inhibitors of phosphatidylinositol 3-kinase, as well as NF-,B. Conclusion These data suggest that binding of LIGHT with its receptors may play a role in the progression of inflammation within rheumatoid synovium, especially by mediating the interactions between infiltrating inflammatory cells and stromal cells. These findings thus emphasize the relevance of LIGHT as a potential therapeutic target in RA. [source] What can humans learn from flies about adenomatous polyposis coli?BIOESSAYS, Issue 9 2002Angela I.M. Barth Somatic or inherited mutations in the adenomatous polyposis coli (APC) gene are a frequent cause of colorectal cancer in humans. APC protein has an important tumor suppression function to reduce cellular levels of the signaling protein ,-catenin and, thereby, inhibit ,-catenin and T-cell-factor-mediated gene expression. In addition, APC protein binds to microtubules in vertebrate cells and localizes to actin-rich adherens junctions in epithelial cells of the fruit fly Drosophila (Fig. 1). Very little is known, however, about the function of these cytoskeletal associations. Recently, Hamada and Bienz have described a potential role for Drosophila E-APC in cellular adhesion,1 which offers new clues to APC function in embryonic development, and potentially colorectal adenoma formation and tumor progression in humans. BioEssays 24:771,774, 2002. © 2002 Wiley Periodicals, Inc. [source] T cell adhesion mechanisms revealed by receptor lateral mobility,BIOPOLYMERS, Issue 5 2008Christopher W. Cairo Cell surface receptors mediate the exchange of information between cells and their environment. In the case of adhesion receptors, the spatial distribution and molecular associations of the receptors are critical to their function. Therefore, understanding the mechanisms regulating the distribution and binding associations of these molecules is necessary to understand their functional regulation. Experiments characterizing the lateral mobility of adhesion receptors have revealed a set of common mechanisms that control receptor function and thus cellular behavior. The T cell provides one of the most dynamic examples of cellular adhesion. An individual T cell makes innumerable intercellular contacts with antigen presenting cells, the vascular endothelium, and many other cell types. We review here the mechanisms that regulate T cell adhesion receptor lateral mobility as a window into the molecular regulation of these systems, and we present a general framework for understanding the principles and mechanisms that are likely to be common among these and other cellular adhesion systems. We suggest that receptor lateral mobility is regulated via four major mechanisms,reorganization, recruitment, dispersion, and anchoring,and we review specific examples of T cell adhesion receptor systems that utilize one or more of these mechanisms. © 2007 Wiley Periodicals, Inc. Biopolymers 89: 409,419, 2008. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] Exploring cellular adhesion and differentiation in a micro-/nano-hybrid polymer scaffoldBIOTECHNOLOGY PROGRESS, Issue 3 2010Ke Cheng Abstract Polymer scaffolds play an important role in three dimensional (3-D) cell culture and tissue engineering. To best mimic the archiecture of natural extracellular matrix (ECM), a nano-fibrous and micro-porous combined (NFMP) scaffold was fabricated by combining phase separation and particulate leaching techniques. The NFMP scaffold possesses architectural features at two levels, including the micro-scale pores and nano-scale fibers. To evaluate the advantages of micro/nano combination, control scaffolds with only micro-pores or nano-fibers were fabricated. Cell grown in NFMP and control scaffolds were characterized with respect to morphology, proliferation rate, diffentiation and adhesion. The NFMP scaffold combined the advantages of micro- and nano-scale structures. The NFMP scaffold nano-fibers promoted neural differentiation and induced "3-D matrix adhesion", while the NFMP scaffold micro-pores facilitated cell infiltration. This study represents a systematic comparison of cellular activities on micro-only, nano-only and micro/nano combined scaffolds, and demonstrates the unique advantages of the later. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] Laminin-5 (laminin-332): Unique biological activity and role in tumor growth and invasionCANCER SCIENCE, Issue 2 2006Kaoru Miyazaki The development and progression of tumor cells is controlled by their interactions with neighboring host cells and a variety of microenvironmental factors including extracellular matrix (ECM) molecules, growth factors and proteinases. Cell-adhesive ECM proteins are a prerequisite for growth and migration of many types of cells. Their interactions with integrins and other cell surface receptors induce intracellular signaling that regulates the actin cytoskeleton and gene expression. The basement membrane protein laminin-5 is a notable cell adhesion molecule, which promotes cellular adhesion and migration much more efficiently than other ECM proteins. There is accumulating evidence that laminin-5 is involved in tumor growth and progression. With special reference to laminin-5, this article reviews the regulatory mechanisms of cellular adhesion and migration by ECM molecules and their significance in tumor progression. (Cancer Sci 2006; 97: 91 , 98) [source] Glycosyltransferases and their AssaysCHEMBIOCHEM, Issue 14 2010Dr. Gerd K. Wagner Abstract Glycosyltransferases (GTs) are a large family of enzymes that are essential in all domains of life for the biosynthesis of complex carbohydrates and glycoconjugates. GTs catalyse the transfer of a sugar from a glycosyl donor to a variety of acceptor molecules, for example, oligosaccharides, peptides, lipids or small molecules. Such glycosylation reactions are central to many fundamental biological processes, including cellular adhesion, cell signalling and bacterial- and plant-cell-wall biosynthesis. GTs are therefore of significant interest as molecular targets in chemical biology and drug discovery. In addition, GTs have found wide application as synthetic tools for the preparation of complex carbohydrates and glycoconjugates. In order to exploit the potential of GTs both as molecular targets and synthetic tools, robust and operationally simple bioassays are essential, especially as more and more protein sequences with putative GT activity but unknown biochemical function are being identified. In this minireview, we give a brief introduction to GT biochemistry and biology. We outline the relevance of GTs for medicinal chemistry and chemical biology, and describe selected examples for recently developed GT bioassays, with a particular emphasis on fluorescence-based formats. [source] Distinction at the leading edge of the cellBIOESSAYS, Issue 4 2005Paul Timpson Cell locomotion is governed by spatially and temporally co-ordinated changes in the organization of the actin cytoskeleton. In the highlighted manuscript,(1) the authors focus on actin remodelling at the front of moving cells to reveal the existence of two distinct yet spatially overlapping actin networks that play largely independent yet fundamental roles in cell migration. The first is defined as the lamellipodium, which assembles and disas sembles within the first 3 ,m of the leading edge. This serves to promote the random protrusion and retraction of the leading edge but has no role in productive cell translocation. The second actin network, the lamella, is responsible for the advancement of the cell by integrating contraction with cellular adhesions. BioEssays 27:349,352, 2005. © 2005 Wiley periodicals, Inc. [source] | |||||||||||||||||||