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The journal of biological chemistry 299(5), 104627 (2023). doi:10.1016/j.jbc.2023.104627, The FimH type-1 fimbrial adhesin allows pathogenic Escherichia coli to adhere to glycoproteins in the epithelial linings of human bladder and intestinal tract, by using multiple fimbriae simultaneously. Pauci- and high-mannose type N-glycans are natural FimH receptors on those glycoproteins. Oligomannose-3 and oligomannose-5 bind with the highest affinity to FimH by using the same Manα1,3Man branch. Oligomannose-6 is generated from oligomannose-5 in the next step of the biogenesis of high-mannose N-glycans, by the transfer of a mannose in α1,2-linkage onto this branch. Using serial crystallography and by measuring the kinetics of binding, we demonstrate that shielding the high-affinity epitope drives the binding of multiple FimH molecules. First, we profiled FimH glycan binding on a microarray containing paucimannosidic N-glycans and in a FimH LEctPROFILE assay. To make the transition to oligomannose-6, we measured the kinetics of FimH binding using paucimannosidic N-glycans, glycoproteins and all four α-dimannosides conjugated to bovine serum albumin. Equimolar mixed interfaces of the dimannosides present in oligomannose-6 and molecular dynamics simulations suggest a positive cooperativity in the bivalent binding of Manα1,3Manα1 and Manα1,6Manα1 dimannosides. The binding of core α1,6-fucosylated oligomannose-3 in cocrystals of FimH is monovalent but interestingly the GlcNAc1—Fuc moiety retains highly flexibility. In cocrystals with oligomannose-6, two FimH bacterial adhesins bind the Manα1,3Manα1 and Manα1,6Manα1 endings of the second trimannose core (A-4′-B). This cooperative switch towards bivalent binding appears sustainable beyond a molar excess of oligomannose-6. Our findings provide important novel structural insights for the design of multivalent FimH antagonists that bind with positive cooperativity., Published by Soc., Bethesda, Md.

Paucimannosidic glycans are restricted to the core structure [Man1–3GlcNAc2Fuc0–1] of N-glycans and are rarely found in mammalian tissues. Yet, especially [Man2-3GlcNAc2Fuc1] have been found significantly upregulated in tumors, including in colorectal and liver cancer. Mannitou IgM is a murine monoclonal antibody that was previously shown to recognize Man3GlcNAc2 with an almost exclusive selectivity. Here, we have sought the definition of the minimal glycan epitope of Mannitou IgM, initiated by screening on a newly designed paucimannosidic glycan microarray; among the best binders were Man3GlcNAc2 and its α1,6 core-fucosylated variant, Man3GlcNAc2Fuc1. Unexpectedly and in contrast to earlier findings, Man5GlcNAc2-type structures bind equally well and a large tolerance was observed for substitutions on the α1,6 arm. It was confirmed that any substitution on the single α1,3-linked mannose completely abolishes binding. Surface plasmon resonance for kinetic measurements of Mannitou IgM binding, either directly on the glycans or as presented on omega-1 and kappa-5 soluble egg antigens from the helminth parasite Schistosoma mansoni, showed submicromolar affinities. To characterize the epitope in greater and atomic detail, saturation transfer difference nuclear magnetic resonance spectroscopy was performed with the Mannitou antigen-binding fragment. The STD-NMR data demonstrated the strongest interactions with the aliphatic protons H1 and H2 of the α1–3-linked mannose and weaker imprints on its H3, H4 and H5 protons. In conclusion, Mannitou IgM binding requires a nonsubstituted α1,3-linked mannose branch of paucimannose also on proteins, making it a highly specific tool for the distinction of concurrent human tumor-associated carbohydrate antigens.

We herein propose the use of fluoroacetamide and difluoroacetamide moieties as sensitive tags for the detection of sugar–protein interactions by simple 1H and/or 19F NMR spectroscopy methods. In this process, we have chosen the binding of N,N′‐diacetyl chitobiose, a ubiquitous disaccharide fragment in glycoproteins, by wheat‐germ agglutinin (WGA), a model lectin. By using saturation‐transfer difference (STD)‐NMR spectroscopy, we experimentally demonstrate that, under solution conditions, the molecule that contained the CHF2CONH‐ moiety is the stronger aromatic binder, followed by the analogue with the CH2FCONH‐ group and the natural molecule (with the CH3CONH‐ fragment). In contrast, the molecule with the CF3CONH‐ isoster displayed the weakest intermolecular interaction (one order of magnitude weaker). Because sugar–aromatic CH–π interactions are at the origin of these observations, these results further contribute to the characterization and exploration of these forces and offer an opportunity to use them to unravel complex recognition processes.

Here, we describe a strategy for the rapid preparation of pure positional isomers of complex N-glycans to complement an existing array comprising a larger number of N-glycans and smaller glycan structures. The expanded array was then employed to study context-dependent binding of structural glycan fragments by monoclonal antibodies and C-type lectins. A partial enzymatic elongation of semiprotected core structures was combined with the protecting-group-aided separation of positional isomers by preparative HPLC. This methodology, which avoids the laborious chemical differentiation of antennae, was employed for the preparation of eight biantennary N-glycans with Galβ1,4GlcNAc (LN), GalNAcβ1,4GlcNAc (LDN), and GalNAcβ1,4[Fucα1,3]GlcNAc (LDNF) motifs presented on either one or both antennae. Screening of the binding specificities of three anti-LeX monoclonal IgM antibodies raised against S. mansoni glycans and three C-type lectin receptors of the innate immune system, namely DC-SIGN, DC-SIGNR, and LSECtin, revealed a surprising context-dependent fine specificity for the recognition of the glycan motifs. Moreover, we observed a striking selection of one individual positional isomer over the other by the C-type lectins tested, underscoring the biological relevance of the structural context of glycan elements in molecular recognition.

Methods for the absolute quantification of glycans are needed in glycoproteomics, during development and production of biopharmaceuticals and for the clinical analysis of glycan disease markers. Here we present a strategy for the chemo-enzymatic synthesis of (13)C labeled N-glycan libraries and provide an example for their use as internal standards in the profiling and absolute quantification of mAb glycans by matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. A synthetic biantennary glycan precursor was (13)C-labeled on all four amino sugar residues and enzymatically derivatized to produce a library of 15 glycan isotopologues with a mass increment of 8 Da over the natural products. Asymmetrically elongated glycans were accessible by performing enzymatic reactions on partially protected UV-absorbing intermediates, subsequent fractionation by preparative HPLC, and final hydrogenation. Using a preformulated mixture of eight internal standards, we quantified the glycans in a monoclonal therapeutic antibody with excellent precision and speed.

Granulomatous slack skin (GSS) is a very rare condition that has been described as a variant of mycosis fungoides. It is characterized by the development of bulky and pendulous skin folds in flexural areas that are histologically formed by atypical T lymphocytes, histiocytes and giant cells. We report the case of a 37-year-old African-American female with history of Sezary syndrome (SS) that while on treatment for the disease and in a space of 1 month developed exorbitant slack folds in the axillae and cervical area mimicking GSS. The absence of giant cells and epithelioid granulomas in the biopsy ruled out this diagnosis. We report this peculiar SS presentation that clinically resembles GSS, but with histopathology that does not show the typical features of this condition. We also review the literature in regard to SS, GSS and granulomatous mycosis fungoides (GMF), particularly the existing criteria to differentiate these various entities.

On November 8, 1610, eleven Basque “witches” were burned at the stake in Logroño, Spain—six alive, five in effigy. Most of these “witches” were women. In this article, I show that the “witches” persecuted in Logroño and those “captured” by Pierre de Lancre in his treatise On the Inconstancy of Witches (1612) deviate widely from those captured in Basque song. The former represent male and female witches as sexually deviant, cannibalistic, poison-procuring servants of the Devil deserving death for profaning God's name and violating his most sacred laws. The latter features witches—always female—as unruly, fun-loving tricksters but certainly not handmaidens of the Devil. I suggest that the lyrical resources released by these Basque songs about witches remain ambiguous and deserve further study.

Glycan arrays have been established as the premier technical platform for assessing the specificity of carbohydrate binding proteins, an important step in functional glycomics research. Access to large libraries of well-characterized oligosaccharides remains a major bottleneck of glycan array research, and this is particularly true for glycosaminoglycans (GAGs), a class of linear sulfated polysaccharides which are present on most animal cells. Solid-supported synthesis is a potentially powerful tool for the accelerated synthesis of relevant GAG libraries with variations in glycan sequence and sulfation pattern. We have evaluated a series of iduronic acid and idose donors, including a couple of novel n-pentenyl orthoester donors in the sequential assembly of heparan sulfate precursors from monosaccharide building blocks in solution and on a polystyrene resin. The systematic study of donor and acceptor performance up to the trisaccharide stage in solution and on the solid support have resulted in a general strategy for the solid-phase assembly of this important class of glycans.

The presence of a subcutaneous foreign body may not be easily suspected after the initial history and exploration of the patient. The authors report a 54-year-old male who came to the Department of Dermatology, Hospital Universitario de Fuenlabrada, Madrid, Spain with a firm plaque, fixed to deep structures, which showed several draining orifices over the costal grid. After several tests, the authors performed an ultrasonography that revealed the presence of a fistula from a foreign body secondary to a previously untreated costal fracture that occurred several years before. The authors believe ultrasonography is a readily available and useful tool that may help dermatologists in daily clinical practice, with the advantage of being a noninvasive test.

The high yielding solid-phase stereoselective assembly of monosaccharide building blocks into advanced oligosaccharide precursors up to the size of an octasaccharide for two important classes of glycosaminoglycans, namely dermatan sulfate and heparan sulfate, is reported.

In this article, I show that despite a seemingly inclusive, language-based identity promoted in schools and pedagogical materials, Basque identity and language are embedded with social histories that exclude large swaths of the would-be Basque nation: women and second language learners of Basque. To the extent that these processes continue to operate in society and are ignored in the curriculum-in-use, it bodes ill for the future of Euskera as a language of everyday use. Specifically, I examine elements of Basque identity, culture and language featured in classrooms or pedagogical materials used to teach Basque language and culture in the Basque Autonomous Community (BAC) of Spain and the diaspora, and show how they are socially constructed to position some kinds of Basques as “more Basque” than others. These social constructions are problematic, in that efforts to revitalize threatened languages like Euskera need to welcome speakers rather than marginalize them.

The synthesis of a collection of 33 xylosylated and core-fucosylated N-glycans found only in nonmammalian organisms such as plants and parasitic helminths has been achieved by employing a highly convergent chemo-enzymatic approach. The influence of these core modifications on the interaction with plant lectins, with the human lectin DC-SIGN (Dendritic Cell-Specific Intercellular adhesion molecule-3-Grabbing Nonintegrin), and with serum antibodies from schistosome-infected individuals was studied. Core xylosylation markedly reduced or completely abolished binding to several mannose-binding plant lectins and to DC-SIGN, a C-type lectin receptor present on antigen presenting cells. Employing the synthetic collection of core-fucosylated and core-xylosylated N-glycans in the context of a larger glycan array including structures lacking these core modifications, we were able to dissect core xylose and core fucose specific antiglycan antibody responses in S. mansoni infection sera, and we observed clear and immunologically relevant differences between children and adult groups infected with this parasite. The work presented here suggests that, quite similar to bisecting N-acetylglucosamine, core xylose distorts the conformation of the unsubstituted glycan, with important implications for the immunogenicity and protein binding properties of complex N-glycans.

Detection of molecular recognition processes requires robust, specific, and easily implementable sensing methods, especially for screening applications. Here, we propose the difluoroacetamide moiety (an acetamide bioisoster) as a novel tag for detecting by NMR analysis those glycan-protein interactions that involve N-acetylated sugars. Although difluoroacetamide has been used previously as a substituent in medicinal chemistry, here we employ it as a specific sensor to monitor interactions between GlcNAc-containing glycans and a model lectin (wheat germ agglutinin). In contrast to the widely employed trifluoroacetamide group, the difluoroacetamide tag contains geminal (1) H and (19) F atoms that allow both (1) H and (19) F NMR methods for easy and robust detection of molecular recognition processes involving GlcNAc- (or GalNAc-) moieties over a range of binding affinities. The CHF2 CONH- moiety behaves in a manner that is very similar to that of the natural acetamide fragment in the involved aromatic-sugar interactions, providing analogous binding energy and conformations, whereas the perfluorinated CF3 CONH- analogue differs more significantly.

This paper examines the effects of Basque- versus Spanish-language schooling on the language attitudes of secondary school students in San Sebastian, in the Basque Autonomous Community (BAC) of Spain. By mandating the teaching of Basque (‘euskera’) in schools, and by requiring Basque proficiency of civil servants, the Basque government is attempting to increase the utility and use of Basque. By teaching people Basque, the Basque Government is also trying to create a link between Basque language and identity. I will show that schooling has no independent effect on language attitudes; rather, positive attitudes towards Basque are correlated with exposure to Basque in both the home and school domains. Further, whether they attend Basque- or Spanish-medium schools, students who speak only Spanish at home exhibit identical language attitudes. Finally, regardless of the language(s) they use at home and school, all students favour vernacular Basque, which is not used for instruction. This suggests that, in devel...

Basque-versus Spanish-schooled students in San Sebastian, Spain, understand ethnic identity differently. The former are more likely to speak Basque and to consider the Basque language key to Basque identity. The latter are more likely to claim “biethnic” identities based on territory. The Basque case suggests that an understanding of educational efforts to reverse language shift require an examination of the language ideologies reigning in popular culture, the public sphere, and the home and school domains.

BackgroundHow do we account for the persistent difficulty the U.S. community of science has in educating larger numbers of talented and diverse undergraduates? We posit that the problem lies in the community's unremitting focus on scientific subject matter knowledge and students’ ability to learn, to the neglect of interpersonal social relations—particularly trust. Our study focuses on trust in academic mentoring. This topic is particularly relevant in studies of the undergraduate segment of the pipeline into science that typically occurs in large, impersonal settings that often generate student alienation. Our study hypothesizes that trustworthy relations may be both a significant condition for academic mentoring as well as an important outcome.PurposeThe study we report explores the promise of a new research direction in undergraduate science education, one focused on trust in academic mentoring. A focus on interpersonal trust is unusual, if not entirely overlooked, in most studies of undergraduate science education, and stands in sharp contrast to the situation in K–12 education where an emergent body of survey and field research measures trust and documents its educational importance. Our framework derives from social capital theory and cautions that a science curriculum that informs and motivates entails attention not only to cognition, as indicated by subject matter knowledge, but also to the educational significance of other complex forms of cognition that undergird social skill, relational awareness, and the development and maintenance of trust.Research DesignBecause the MARC-U*STAR training program funded by the National Institutes of Health sponsors only a select number of talented upper division science major students on each host campus, our correlational analyses were based on a unique and relatively small sample of data collected from undergraduate science major students (N=161) in 16 colleges and universities in the Pacific Southwest. We analyzed the data in two linked parts: (a) an analysis of the association between trust and motivation; and (b) an evaluation of whether the Program affects trust. We link the two parts by using the same longitudinal dataset in each and, further, by building the evaluation on the findings from models that compare trust and motivation among upper division science major students enrolled in the Program (n=49) with trust and motivation among upper division science major students not in the Program (n=112). Given the study's exploratory purpose and design limits, we situate the results near the front end of the continuum from preliminary studies designed to suggest further research directions to the kinds of precise predictions we can expect from truly randomized controlled experiments.FindingsDespite its necessarily preliminary findings regarding trust, this study contributes to the literature on academic mentoring in undergraduate science education in several ways. First, our study develops a novel conceptual perspective on the measure and utility of trust as a crucial form of social capital. Second, we used this perspective to develop a set of structural models that suggest interpersonal trust is producible in undergraduate science education; is pedagogically powerful, not a mere nicety; and is particularly important for students who are members of groups historically underrepresented in the sciences. Third, and surprising because the literature on trust does not prepare for them, are results suggesting that trust may work differently for different groups of students in different contexts.Conclusions/RecommendationsOur findings are unusual and encouraging, and they bring several issues to light regarding (a) the utility of theory in research and practice in undergraduate science education, (b) inequitable representation in the sciences, and (c) contextual complexities that condition the development and maintenance of trust within institutional settings. First, our framework on trust derives from social capital theory and cautions that a science curriculum that informs and motivates entails attention not only to cognition but also to the educational significance of other complex forms of cognition that undergird social skill, relational awareness, and the development and maintenance of trust. In cognitively and socially consequential exchanges in undergraduate science education, trust and mistrust are important. Next, our most unusual finding—that trust in a mentor seems to matter more for the motivation and career expectations of the MARC-U*STAR Program students than for non-Program students—raises the question: How does trust in a university mentor matter for equitable undergraduate education in science? With our data, we cannot fully account for this unexpected finding. Drawing from studies that disentangle the concept of interpersonal trust from more generalized notions of trust in the social environment, we have worked at a tentative interpretation: Perhaps interpersonal trust is especially impactful in situations where the more general social environment poses perceptible threats. Last, when the literature on trust is examined concurrently with our findings, trust emerges not as an invariant entity, but as supremely contextualized. We conclude by calling for a more expansive, multidisciplinary, and multimethod research agenda focused on trust, which may contribute to a reorientation of undergraduate science education.

Following a framework developed by Susan Gal and Judith Irvine (1995), this article illustrates how Basque-medium schools promulgate an androcentric vision of the Basque nation. First, male privilege is upheld in textbooks through the erasure of women's contributions to Basque language and culture, so that men appear as the quintessential Basque speakers and cultural agents. Secondly, language ideologies about Spanish and Basque recursively construct Basque ethnic identity is such a way that it centres on vernacular Basque, whose primary marker is a second person pronoun, ‘hi’, which indirectly indexes male speakers and masculinity. An iconic relationship is thereby created between authentic Basque identity, Basque culture, Basque linguistic forms and masculinity. However, I also show that women have challenged this male privilege in various domains, thereby opening up the possibility of a Basque nation that embraces its female as well as its male members.

Debating Diversity: Analysing the Discourse of Tolerance. Jan Blommaert and Jef Verschueren. London: Routledge, 1998. xiv. 233 pp.

Background: Cytomegalovirus (CMV) infection usually remains asymptomatic in immunocompetent adults, and few cases of complicated disease in nonimmunosuppressed patients have been reported. Erythema multiforme (EM), an acute and self-limiting skin eruption characterized by a typical targetoid lesion that may also affect the mucosa, is a hypersensitivity reaction that usually occurs after herpes simplex virus infection or use of certain drugs and resolves without complications in healthy individuals. To our knowledge, CMV infection has been associated with EM in only six patients. Objective: We present a case of an EM caused by CMV infection in a 35-year-old nonimmunosuppressed patient who was successfully treated with ganciclovir. Conclusion: Our report, like other similar reports found in the literature, suggests that CMV can trigger EM in apparently healthy individuals. Intravenous ganciclovir appears to be a good treatment option in these cases.

Stanton Wortham & Betsy Rymes (eds.), Linguistic anthropology of education. Westport, CT: Praeger, 2003. Pp. 288. Hb $69.95.In his introduction to this volume, Stanton Wortham argues for the value of a linguistic anthropological approach to education. After all, “a society's beliefs about language – as a symbol of nationalism, a marker of differences, or a tool of assimilation – are often reproduced and challenged through educational institutions” (p. 2). So too is language used in schools in ways that, often unwittingly, reproduce the inequities in society more generally; a linguistic anthropological approach is particularly well suited to pointing out the processes by which this happens.

This book uses a feminist, poststructuralist perspective to examine the relationships among gender, second language acquisition and multilingualism. It is a welcome addition to the study of these topics, which are usually examined separately. Gender is rarely considered in research on second language acquisition, and most studies of language and gender are conducted in monolingual contexts. This volume proposes a new interdisciplinary approach to these issues which “strives to theorize and to investigate the role of language in the production of gender relations, and role of gender dynamics in language learning and use” (p. 22).