Carbohydrate–carbohydrate interaction provides adhesion force and specificity for cellular recognition

© 2004 Bucior et al. This article is distributed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. The definitive version was published in Journal of Cell Biology 165 (2004): 529-537, doi:10.1083/jcb.200309005.The adhesion force and specificity in the first experimental evidence for cell–cell recognition in the animal kingdom were assigned to marine sponge cell surface proteoglycans. However, the question whether the specificity resided in a protein or carbohydrate moiety could not yet be resolved. Here, the strength and species specificity of cell–cell recognition could be assigned to a direct carbohydrate–carbohydrate interaction. Atomic force microscopy measurements revealed equally strong adhesion forces between glycan molecules (190–310 piconewtons) as between proteins in antibody–antigen interactions (244 piconewtons). Quantitative measurements of adhesion forces between glycans from identical species versus glycans from different species confirmed the species specificity of the interaction. Glycan-coated beads aggregated according to their species of origin, i.e., the same way as live sponge cells did. Live cells also demonstrated species selective binding to glycans coated on surfaces. These findings confirm for the first time the existence of relatively strong and species-specific recognition between surface glycans, a process that may have significant implications in cellular recognition.This work was supported by the Friedrich Miescher Institute, branch of the Novartis Research Foundation, the M.E. Müller Foundation, and the Swiss National Research Foundatio

Women and Public Life in Early Meiji Japan

Women and Public Life in Early Meiji Japan focuses on women’s activities in the new public spaces of Meiji Japan. With chapters on public, private, and missionary schools for girls, their students, and teachers, on social and political groups women created, on female employment, and on women’s participation in print media, this book offers a new perspective on nineteenth- and early twentieth-century Japanese history. Women’s founding of and participation in conflicting discourses over the value of women in Meiji public life demonstrate that during this period active and vocal women were everywhere, that they did not meekly submit to the dictates of the government and intellectuals over what women could or should do, and that they were fully integrated in the production of Meiji culture. Mara Patessio shows that the study of women is fundamental not only in order to understand fully the transformations of the Meiji period, but also to understand how later generations of women could successfully move the battle forward. Women and Public Life in Early Meiji Japan is essential reading for all students and teachers of 19th- and early 20th-century Japanese history and is of interest to scholars of women’s history more generally

Women and Public Life in Early Meiji Japan

Women and Public Life in Early Meiji Japan focuses on women’s activities in the new public spaces of Meiji Japan. With chapters on public, private, and missionary schools for girls, their students, and teachers, on social and political groups women created, on female employment, and on women’s participation in print media, this book offers a new perspective on nineteenth- and early twentieth-century Japanese history. Women’s founding of and participation in conflicting discourses over the value of women in Meiji public life demonstrate that during this period active and vocal women were everywhere, that they did not meekly submit to the dictates of the government and intellectuals over what women could or should do, and that they were fully integrated in the production of Meiji culture. Mara Patessio shows that the study of women is fundamental not only in order to understand fully the transformations of the Meiji period, but also to understand how later generations of women could successfully move the battle forward. Women and Public Life in Early Meiji Japan is essential reading for all students and teachers of 19th- and early 20th-century Japanese history and is of interest to scholars of women’s history more generally

The Public Sphere, Mass Media, Fashion and the Identity of the Individual

It should have become clear by now that the following discussion will be theoretical in perspective. Historical studies, like any other form of science, cannot be conducted without a theoretical framework. Sometimes, we are unaware of the distinctions we draw before we search for material, select and interpret it; some even think that we should just let the sources speak for themselves. Nevertheless, no material can speak for itself: it can only answer to questions we ask. And these questions we ask are dependent on our present preconceptions of bygone societies and their historical development; as every hermeneutic endeavour, historical studies begins with a Vorurteil (prejudice). Many studies of the eighteenth-century public sphere have started out from those conceptions outlined by Habermas; as mentioned above, most of these studies found fault in Habermas's description of the eighteenth century and revealed his preconception as a prejudice. However, by exposing Habermas's approach as ideological, it seemed easy to claim a common-sense, bias-free position for oneself. I do not think such a position is possible: the hermeneutic Vorurteil can never be overcome entirely; it can only be adequately reflected and adjusted. Rather than claiming to work without all preconceptions, one should, I think, try to explicate one's theoretical framework as precisely as possible. If there really are too many findings that cannot be integrated into Habermas's model, one should look for a new model that might be better suited to give meaning to new historical evidence. It is such a new theoretical framework that I want to propose here. In order to do so, a meticulously detailed examination of Habermas's framework is necessary to find out which theoretical decisions led to the shortcomings of his approach. Following this re-examination, I will try to construct a new framework that avoids Habermas's shortcomings. Of course, this new theoretical framework will only be as good as the extent to which it is able to integrate historical evidence and extricate meaningful answers from these sources. Unfortunately, however, there is not enough space here to put the new framework to the test - that will have to be done elsewhere

Carbohydrate-carbohydrate interaction provides adhesion force and specificity for cellular recognition and adhesion

Carbohydrates at the cell surface have been proposed as mediators in cell-cell recognition events involved in embryogenesis, metastasis, and other proliferation processes by calcium-dependent carbohydrate to carbohydrate interactions. They are the most prominently exposed structures on the surface of living cells, and with flexible chains and many binding sites are ideal to serve as the major players in initiating these cellular events. However, biological relevance of these type interactions is often questioned because of the very low affinity binding of single carbohydrate molecules and that they manifest themselves only through the contact of a large number of molecules tightly arranged in the membrane. Weak interactions are considerably more difficult to study and only a few biologically significant examples of direct carbohydrate-carbohydrate interactions have been reported, e.g. pioneering work showing glycosphingolipid self-interactions through multivalent interaction of Lewis X epitopes. However, there are no reports on the existence of specific proteoglycan self-interactions through carbohydrate-carbohydrate interactions in cellular recognition system, as it has been done with glycosphingolipids. Here, we used sponges, organisms on which the first proteoglycan-mediated cell-cell recognition in the animal kingdom was demonstrated, as a model system to study carbohydrate-mediated cellular recognition. We show that the interaction between single oligosaccharides from surface proteoglycans is relatively strong and comparable to protein-carbohydrate interactions, highly specific, and dependent on Ca2+-ions. 200 kDa glycans from the core protein of Microciona prolifera cell surface proteoglycans have been previously shown to mediate homotypic Microciona proteoglycan-proteoglycan interactions. Here, 200 kDa glycans from four different sponge species: Microciona prolifera, Halichondria panicea, Suberites fuscus and Cliona celata were purified and investigated for species-specific interactions. Selective recognition of glycans by live cells was studied to confirm the existence of glycan-glycan recognition system in biologically relevant situations. Mature sponge cells have the ability to reaggregate species-specifically and form homogenous aggregates on a shaker at the right shear forces in the presence of physiological 10 mM Ca2+. Live cells were allowed to aggregate with glycan-coated beads similar in size to small sponge cells in the presence of calcium. They specifically recognized beads coated with their own glycans and did not mix but separated from beads coated with glycans isolated from different species. The glycan-glycan recognition assay was developed to mimic species-specific cellcell recognition in sponges. 200 kDa glycans immobilized onto beads similar in size to small sponge cells assembled species-specifically in the presence of physiological calcium, at the same shear forces as in cell-cell aggregation. Glycans coated on beads aggregated with glycans from the same species coated on beads, and separated from glycans from other species. The glycan density necessary for specific live cellcell recognition in sponges is 828 molecules/μm2. In our studies, the glycan density necessary for specific glycan-coated bead was very similar: ~810 molecules/μm2. Mature live cells demonstrated specific recognition of 200 kDa glycans during selective-binding to glycans coated on surfaces in the presence of calcium. They strongly adhered to glycans from their own surface proteoglycans coated onto a solid polystyrene phase, while the binding to glycans from different proteoglycans was 3 - 5 times lower. Moreover, homotypic adhesion to glycan-coated plates enhanced sponge cell differentiation and formation of mineral skeleton (spicules). Larval cells, after settlement and spreading of larvae, can fuse species-specifically in nature. In our studies, live larval cells recognized and adhered specifically to glycans purified from adhesion proteoglycans from their "mother sponge". They showed almost no interaction with glycans from other species. As in cell-glycan adhesion assays, highly species-specific adhesion of 200 kDa glycans to glycan-coated surfaces could be observed in the presence of physiological calcium. Tested glycans bound strongly to glycans from the same species and showed up to a six fold reduction in binding to glycans from other species. Atomic force microscopy (AFM) was performed to measure for the first time adhesion forces between single glycan molecules obtained from different surface proteoglycans. Measurements revealed equally strong adhesion forces in the range of several hundred piconewtons (pN) between glycan molecules as between proteins and glycans measured in another recognition system. Moreover, statistically significant differences (p value < 0.01) were seen between homotypic (glycans from the same species) and heterotypic (glycans from different species) interactions. Moreover, the polyvalent character of binding characterized mainly interactions between glycans from the same species. This indicates that not only the higher adhesion force per binding site as such but also the higher amount of multiple interactions between glycans from the same species versus mixture of glycans from different species guaranteed the specificity of the glycan-mediated recognition. These findings confirm for the first time the existence of specific glycan-glycan recognition system between cell surface proteoglycans. We propose that these cell's outermost surface structures serve as important players in initiating the very first contacts between cells through highly species-specific and flexible carbohydratecarbohydrate interactions

Carbohydrate-carbohydrate interaction provides adhesion force and specificity for cellular recognition and adhesion

Carbohydrates at the cell surface have been proposed as mediators in cell-cell recognition events involved in embryogenesis, metastasis, and other proliferation processes by calcium-dependent carbohydrate to carbohydrate interactions. They are the most prominently exposed structures on the surface of living cells, and with flexible chains and many binding sites are ideal to serve as the major players in initiating these cellular events. However, biological relevance of these type interactions is often questioned because of the very low affinity binding of single carbohydrate molecules and that they manifest themselves only through the contact of a large number of molecules tightly arranged in the membrane. Weak interactions are considerably more difficult to study and only a few biologically significant examples of direct carbohydrate-carbohydrate interactions have been reported, e.g. pioneering work showing glycosphingolipid self-interactions through multivalent interaction of Lewis X epitopes. However, there are no reports on the existence of specific proteoglycan self-interactions through carbohydrate-carbohydrate interactions in cellular recognition system, as it has been done with glycosphingolipids. Here, we used sponges, organisms on which the first proteoglycan-mediated cell-cell recognition in the animal kingdom was demonstrated, as a model system to study carbohydrate-mediated cellular recognition. We show that the interaction between single oligosaccharides from surface proteoglycans is relatively strong and comparable to protein-carbohydrate interactions, highly specific, and dependent on Ca2+-ions. 200 kDa glycans from the core protein of Microciona prolifera cell surface proteoglycans have been previously shown to mediate homotypic Microciona proteoglycan-proteoglycan interactions. Here, 200 kDa glycans from four different sponge species: Microciona prolifera, Halichondria panicea, Suberites fuscus and Cliona celata were purified and investigated for species-specific interactions. Selective recognition of glycans by live cells was studied to confirm the existence of glycan-glycan recognition system in biologically relevant situations. Mature sponge cells have the ability to reaggregate species-specifically and form homogenous aggregates on a shaker at the right shear forces in the presence of physiological 10 mM Ca2+. Live cells were allowed to aggregate with glycan-coated beads similar in size to small sponge cells in the presence of calcium. They specifically recognized beads coated with their own glycans and did not mix but separated from beads coated with glycans isolated from different species. The glycan-glycan recognition assay was developed to mimic species-specific cellcell recognition in sponges. 200 kDa glycans immobilized onto beads similar in size to small sponge cells assembled species-specifically in the presence of physiological calcium, at the same shear forces as in cell-cell aggregation. Glycans coated on beads aggregated with glycans from the same species coated on beads, and separated from glycans from other species. The glycan density necessary for specific live cellcell recognition in sponges is 828 molecules/μm2. In our studies, the glycan density necessary for specific glycan-coated bead was very similar: ~810 molecules/μm2. Mature live cells demonstrated specific recognition of 200 kDa glycans during selective-binding to glycans coated on surfaces in the presence of calcium. They strongly adhered to glycans from their own surface proteoglycans coated onto a solid polystyrene phase, while the binding to glycans from different proteoglycans was 3 - 5 times lower. Moreover, homotypic adhesion to glycan-coated plates enhanced sponge cell differentiation and formation of mineral skeleton (spicules). Larval cells, after settlement and spreading of larvae, can fuse species-specifically in nature. In our studies, live larval cells recognized and adhered specifically to glycans purified from adhesion proteoglycans from their "mother sponge". They showed almost no interaction with glycans from other species. As in cell-glycan adhesion assays, highly species-specific adhesion of 200 kDa glycans to glycan-coated surfaces could be observed in the presence of physiological calcium. Tested glycans bound strongly to glycans from the same species and showed up to a six fold reduction in binding to glycans from other species. Atomic force microscopy (AFM) was performed to measure for the first time adhesion forces between single glycan molecules obtained from different surface proteoglycans. Measurements revealed equally strong adhesion forces in the range of several hundred piconewtons (pN) between glycan molecules as between proteins and glycans measured in another recognition system. Moreover, statistically significant differences (p value < 0.01) were seen between homotypic (glycans from the same species) and heterotypic (glycans from different species) interactions. Moreover, the polyvalent character of binding characterized mainly interactions between glycans from the same species. This indicates that not only the higher adhesion force per binding site as such but also the higher amount of multiple interactions between glycans from the same species versus mixture of glycans from different species guaranteed the specificity of the glycan-mediated recognition. These findings confirm for the first time the existence of specific glycan-glycan recognition system between cell surface proteoglycans. We propose that these cell's outermost surface structures serve as important players in initiating the very first contacts between cells through highly species-specific and flexible carbohydratecarbohydrate interactions