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Metabolic incorporation of chemically tagged monosaccharides is a facile means of tagging cellular glycoproteins and glycolipids. However, since the monosaccharide precursors are often shared by several pathways, selectivity has been difficult to attain. For example, N-linked glycosylation is a chemically complex and ubiquitous posttranslational modification, with three distinct classes of GlcNAc-containing N-glycan structures: oligomannose, hybrid and complex. Here we describe the synthesis of 1,3-Pr 2 -6-OTs GlcNAlk (MM-JH-1) as a next-generation metabolic chemical reporter for the selective labeling of hybrid N-glycan structures. We first developed a general strategy for defining the selectivity of labeling with chemically tagged monosaccharides. We then applied this approach to establish that MM-JH-1 is selectively incorporated into hybrid N-glycans. Using this metabolic chemical reporter as a detection tool, we performed imaging and fractionation to define features of the intracellular localization and trafficking of target proteins bearing hybrid N-glycan structures., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Metabolic chemical reporters (MCRs) provide easily accessible means to study glycans in their native environments. However, because monosaccharide precursors are shared by many glycosylation pathways, selective incorporation has been difficult to attain. Here, a strategy for defining the selectivity and enzymatic incorporation of an MCR is presented. Performing β-elimination to interrogate O -linked sugars and using commercially available glycosidases and glycosyltransferase inhibitors, we probed the specificity of widely used azide (Ac 4 GalNAz) and alkyne (Ac 4 GalNAlk and Ac 4 GlcNAlk) sugar derivatives. Following the outlined strategy, we provide a semiquantitative assessment of the specific and non-specific incorporation of this bioorthogonal sugar (Ac 4 GalNAz) into numerous N - and O -linked glycosylation pathways. This approach should be generally applicable to other MCRs to define the extent of incorporation into the various glycan species., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer CF declared a past co-authorship with the author JAH to the handling editor., (Copyright © 2023 Mukherjee, Bond, Abramowitz, Biesbrock, Woodroofe, Kim, Swenson and Hanover.)

Metabolic incorporation of chemically tagged monosaccharides is a facile means of labelling cellular glycoprotein and glycolipids. Yet, since the monosaccharide precursors are often shared by several pathways, selectivity has been difficult to attain. For example, N -linked glycosylation is a chemically complex, and ubiquitous post translational modification with three distinct classes of GlcNAc-containing N -glycan structures: oligomannose, hybrid, and complex. Here we describe synthesis of 1,3-Pr 2 -6-OTs GlcNAlk as a next generation metabolic chemical reporter (MCR) for the specific labeling of hybrid N -glycan structures. We first developed a general strategy for defining the selectivity of labelling with chemically tagged monosaccharides. We then applied this approach to establish that 1,3-Pr 2 -6-OTs GlcNAlk is specifically incorporated into hybrid N -glycans. Using this MCR as a detection tool, we carried out imaging experiments to define the intracellular localization and trafficking of target proteins bearing hybrid N -glycan structures.

Background: Severe headaches are common after subarachnoid hemorrhage. Guidelines recommend treatment with acetaminophen and opioids, but patient data show that headaches often persist despite multimodal treatment approaches. Considering an overall slim body of data for a common complaint affecting patients with SAH during their intensive care stay, we set out to assess practice patterns in headache management among clinicians who treat patients with SAH., Methods: We conducted an international cross-sectional study through a 37-question Web-based survey distributed to members of five professional societies relevant to intensive and neurocritical care from November 2021 to January 2022. Responses were characterized through descriptive analyses. Fisher's exact test was used to test associations., Results: Of 516 respondents, 329 of 497 (66%) were from North America and 121 of 497 (24%) from Europe. Of 435 respondents, 379 (87%) reported headache as a major management concern for patients with SAH. Intensive care teams were primarily responsible for analgesia during hospitalization (249 of 435, 57%), whereas responsibility shifted to neurosurgery at discharge (233 of 501, 47%). Most used medications were acetaminophen (90%), opioids (66%), corticosteroids (28%), and antiseizure medications (28%). Opioids or medication combinations including opioids were most frequently perceived as most effective by 169 of 433 respondents (39%, predominantly intensivists), followed by corticosteroids or combinations with corticosteroids (96 of 433, 22%, predominantly neurologists). Of medications prescribed at discharge, acetaminophen was most common (303 of 381, 80%), followed by opioids (175 of 381, 46%) and antiseizure medications (173 of 381, 45%). Opioids during hospitalization were significantly more prescribed by intensivists, by providers managing higher numbers of patients with SAH, and in Europe. At discharge, opioids were more frequently prescribed in North America. Of 435 respondents, 299 (69%) indicated no change in prescription practice of opioids with the opioid crisis. Additional differences in prescription patterns between continents and providers and while inpatient versus at discharge were found., Conclusions: Post-SAH headache in the intensive care setting is a major clinical concern. Analgesia heavily relies on opioids both in use and in perception of efficacy, with no reported change in prescription patterns for opioids for most providers despite the significant drawbacks of opioids. Responsibility for analgesia shifts between hospitalization and discharge. International and provider-related differences are evident. Novel treatment strategies and alignment of prescription between providers are urgently needed., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and Neurocritical Care Society.)

Carbohydrates involving glycoconjugates play a pivotal role in many life processes. Better understanding toward glycobiological events including the structure-function relationship of these biomolecules and for diagnostic and therapeutic purposes including tailor-made vaccine development and synthesis of structurally well-defined oligosaccharides (OS) become important. Efficient chemical glycosylation in high yield and stereoselectivity is however challenging and depends on the fine tuning of a protection profile to get matching glycosyl donor-acceptor reactivity along with proper use of other important external factors like catalyst, solvent, temperature, activator, and additive. So far, many glycosylation methods have been reported including several reviews also. In the present review, we will concentrate our discussion on the recent trend on α- and β-selective glycosylation reactions reported during the past decade., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Mukherjee, Ghosh and Hanover.)

Cellular identity in multicellular organisms is maintained by characteristic transcriptional networks, nutrient consumption, energy production and metabolite utilization. Integrating these cell-specific programs are epigenetic modifiers, whose activity is often dependent on nutrients and their metabolites to function as substrates and co - factors. Emerging data has highlighted the role of the nutrient-sensing enzyme O- GlcNAc transferase (OGT) as an epigenetic modifier essential in coordinating cellular transcriptional programs and metabolic homeostasis. OGT utilizes the end-product of the hexosamine biosynthetic pathway to modify proteins with O- linked β-D- N -acetylglucosamine ( O- GlcNAc). The levels of the modification are held in check by the O- GlcNAcase (OGA). Studies from model organisms and human disease underscore the conserved function these two enzymes of O- GlcNAc cycling play in transcriptional regulation, cellular plasticity and mitochondrial reprogramming. Here, we review these findings and present an integrated view of how O- GlcNAc cycling may contribute to cellular memory and transgenerational inheritance of responses to parental stress. We focus on a rare human genetic disorder where mutant forms of OGT are inherited or acquired de novo . Ongoing analysis of this disorder, OGT- X-linked intellectual disability (OGT-XLID), provides a window into how epigenetic factors linked to O- GlcNAc cycling may influence neurodevelopment., (Copyright © 2020 Konzman, Abramowitz, Steenackers, Mukherjee, Na and Hanover.)

Owing to the environmental concern worldwide and also due to cost, time and labour issues, use of one-pot reactions [domino/cascade/tandem/multi-component (MC) or sequential] has gained much attention among the scientific and industrial communities for the generation of compound libraries having different scaffolds. Inclusion of sugars in such compounds is expected to increase the pharmacological efficacy because of the possibility of better interactions with the receptors of such unnatural glycoconjugates. In many of the one-pot transformations, the presence of a metal salt/complex can improve the reaction/change the course of reaction with remarkable increase in chemo-/regio-/stereo-selectivity. On the other hand because of the importance of natural polymeric glycoconjugates in life processes, the development and efficient synthesis of related oligosaccharides, particularly utilising one-pot MC-glycosylation techniques are necessary. The present review is an endeavour to discuss one-pot transformations involving carbohydrates catalysed by a metal salt/complex., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

An efficient and high yielding reaction for tandem opening of 4,6-O-benzylidene derivatives (gluco, galacto, manno, 2-phthalimido-2-deoxy glucosides) to their corresponding 6-O-acetyl derivatives has been established under metal free condition using 60% solution of aqueous acetic acid (v/v). The reaction is equally pertinent for large scale synthesis and also for disaccharide glycosides. Its application for the construction of a building block towards synthesis of a trisaccharide part related to Pseudomonas aeruginosa utilizing one-pot glycosylation reactions has also been described., (Copyright © 2019. Published by Elsevier Ltd.)

Synthesis of the upstream terminal hexasaccharide part of the lipopolysaccharides (LPS) of Vibrio cholerae O1, serotype Inaba has been improved. The key improvements include but are not limited to optimized conditions for the stereoselectivity of glycosylation reactions involved and fewer number of synthetic steps, compared to previous approaches. Particularly noteworthy is conducting the glycosylation of the very reactive glycosyl acceptor 8-azido-3,6-dioxaoctanol with the fully assembled hexasaccharide trichloroacetimidate under thermodynamic control. It produced the desired α glycoside with an α:β ratio of 7:1, compared with the ratio of 1.1:1, observed when the coupling was conducted conventionally. Several substances, which were previously obtained in purity acceptable only for synthetic intermediates, were now obtained in the analytically pure state and were fully characterized. The structure of the key trisaccharide glycosyl acceptor was confirmed by single-crystal x-ray structure determination., Competing Interests: Conflicts of interest There are no conflicts to declare.

Streptococcus pneumonia (SPn) is a Gram-positive bacterium which causes life threatening diseases. The bacteria protect themselves against non-specific host defence by an external polysaccharide (PS) capsule which bears a repeating unit, α-D-Galp(1->3)-α-D-Glcp(1->3)-α-L-Rhap(1->3)-D-Rib (SPn 6A). A closer look at the structure reveals the presence of α-linked galactose and glucose residues. The synthesis of these 1,2- cis glycosidic linkages are considered challenging particularly in the context of a one-pot oligosaccharide synthesis. We have synthesized the aforesaid tetrasaccharide (SPn 6A) based on both stepwise and sequential one-pot glycosylation reactions using easily accessible common building blocks; eventually similar overall yields were obtained in both cases.

The causative agent of cholera, Vibrio cholerae, is a public health concern. Multidrug-resistant V. cholerae variants may reduce chemotherapeutic efficacies of severe cholera. We previously reported that the multidrug efflux pump EmrD-3 from V. cholerae confers resistance to multiple structurally distinct antimicrobials. Medicinal plant compounds are potential candidates for EmrD-3 efflux pump modulation. The antibacterial activities of garlic Allium sativum, although poorly understood, predicts that a main bioactive component, allyl sulfide, modulates EmrD-3 efflux. Thus, we tested whether A. sativum extract acts in synergy with antimicrobials and that a main bioactive component allyl sulfide inhibits EmrD-3 efflux. We found that A. sativum extract and allyl sulfide inhibited ethidium bromide efflux in cells harboring EmrD-3 and that A. sativum lowered the MICs of multiple antibacterials. We conclude that A. sativum and allyl sulfide inhibit EmrD-3 and that A. sativum extract synergistically enhances antibacterial agents.

Concise syntheses of the acidic pentasaccharide, related to the O-antigenic polysaccharide of Escherichia coli 120, as its p-methoxyphenyl glycoside, have been achieved using a one-pot sequential glycosylation technique. The glycosylations have been accomplished either by the activation of the thioglycosides using NIS in the presence of FeCl 3 or by a preactivation by Ph 2 SO, TTBP, Tf 2 O, and the activation of the trichloroacetimidates using FeCl 3 alone or TMSOTf. Most of the intermediate steps are high yielding, and the stereo outcomes of the glycosylation steps were excellent. The syntheses of the targeted pentasaccharide have been performed with both three- and four-component, one-pot sequential glycosylation reactions, and in both cases, the orthogonal glycosylations are carried out utilizing catalytic activity of FeCl 3 . A late-stage TEMPO-mediated regioselective oxidation has been performed to achieve the required uronic acid motif.

Infection with high-risk human papillomavirus (HR-HPV) is transient and clears on its own in majority of the women. Only a few women who have persistent infection may finally develop cervical intraepithelial neoplasia (CIN) or cervical cancer in later years. The risk of progression in the HR-HPV-positive women with normal cervix or low-grade lesion on colposcopy and histopathology at baseline is less studied. We performed a longitudinal study on 650 HR-HPV-positive women with colposcopy and/or histopathology-proved normal or CIN1 diagnosis at baseline to assess the cumulative risk of development of high-grade CIN. After a mean follow-up of 2.1 person years of observation (PYO) (range 0.1-5.1), the cumulative incidence of CIN2+ (6.4%; 3.0/100 PYO) was significantly higher in women who had persistent HR-HPV infection compared to those who cleared the infection (adjusted HR 6.28; 95% CI 2.87-13.73). The risk of viral persistence in women aged 50-60 years was two times higher compared to women aged 40-49 years and three times higher compared to women aged 30-39 years. The probability of having persistent infection increased progressively with higher viral load at baseline (adjusted HR 3.29, 95% CI 2.21-4.90 for RLU ≥100; adjusted HR 2.69, 95% CI 1.71-4.22 for RLU 10-100). Women with increasing viral load at follow-up had four times higher risk of developing CIN2 or worse lesions as compared to those with decreasing load (20.9% vs 4.8%; p < 0.001). In the context of developing countries where cytology or genotyping triaging is not feasible, colposcopy referral of HR-HPV-positive women with advancing age, viral persistence, and increasing viral load may be considered., (© 2017 UICC.)

Foodborne illnesses caused by bacterial microorganisms are common worldwide and constitute a serious public health concern. In particular, microorganisms belonging to the Enterobacteriaceae and Vibrionaceae families of Gram-negative bacteria, and to the Staphylococcus genus of Gram-positive bacteria are important causative agents of food poisoning and infection in the gastrointestinal tract of humans. Recently, variants of these bacteria have developed resistance to medically important chemotherapeutic agents. Multidrug resistant Escherichia coli, Salmonella enterica, Vibrio cholerae, Enterobacter spp., and Staphylococcus aureus are becoming increasingly recalcitrant to clinical treatment in human patients. Of the various bacterial resistance mechanisms against antimicrobial agents, multidrug efflux pumps comprise a major cause of multiple drug resistance. These multidrug efflux pump systems reside in the biological membrane of the bacteria and actively extrude antimicrobial agents from bacterial cells. This review article summarizes the evolution of these bacterial drug efflux pump systems from a molecular biological standpoint and provides a framework for future work aimed at reducing the conditions that foster dissemination of these multidrug resistant causative agents through human populations.

The biological membrane is an efficient barrier against water-soluble substances. Solute transporters circumvent this membrane barrier by transporting water-soluble solutes across the membrane to the other sides. These transport proteins are thus required for all living organisms. Microorganisms, such as bacteria, effectively exploit solute transporters to acquire useful nutrients for growth or to expel substances that are inhibitory to their growth. Overall, there are distinct types of related solute transporters that are grouped into families or superfamilies. Of these various transporters, the major facilitator superfamily (MFS) represents a very large and constantly growing group and are driven by solute- and ion-gradients, making them passive and secondary active transporters, respectively. Members of the major facilitator superfamily transport an extreme variety of structurally different substrates such as antimicrobial agents, amino acids, sugars, intermediary metabolites, ions, and other small molecules. Importantly, bacteria, especially pathogenic ones, have evolved multidrug efflux pumps which belong to the major facilitator superfamily. Furthermore, members of this important superfamily share similar primary sequences in the form of highly conserved sequence motifs that confer useful functional properties during transport. The transporters of the superfamily also share similarities in secondary structures, such as possessing 12- or 14-membrane spanning α-helices and the more recently described 3-helix structure repeat element, known as the MFS fold. The three-dimensional structures of bacterial multidrug efflux pumps have been determined for only a few members of the superfamily, all drug pumps of which are surprisingly from Escherichia coli . This review briefly summarizes the structural properties of the bacterial multidrug efflux pumps of the major facilitator superfamily in a comparative manner and provides future directions for study.

Bacterial infections pose a serious public health concern, especially when an infectious disease has a multidrug resistant causative agent. Such multidrug resistant bacteria can compromise the clinical utility of major chemotherapeutic antimicrobial agents. Drug and multidrug resistant bacteria harbor several distinct molecular mechanisms for resistance. Bacterial antimicrobial agent efflux pumps represent a major mechanism of clinical resistance. The major facilitator superfamily (MFS) is one of the largest groups of solute transporters to date and includes a significant number of bacterial drug and multidrug efflux pumps. We review recent work on the modulation of multidrug efflux pumps, paying special attention to those transporters belonging primarily to the MFS.

The prevalence study of thumb digital sucking carried out on 3-12-year- old 2517 children, 1293 boys & 1224 girls, with different socio-economic status, belonging to villages, suburbs and city areas of Calcutta revealed that non-nutritional sucking habit was predominantly seen in cities, and bottle feeding was found to be the main cause of this habit; in 3-6-year-old children the prevalence of the habit was more in boys than girls but it persisted more in boys with increase in age.