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There is a growing interest in the introduction of cyclic voltammetry to upper-level undergraduate chemistry students. This work presents a simple buffer-free cyclic voltammetry experiment for the quantification of elemental iron in ferrous sulfate supplements using standard addition to a single solution. The various student learning outcomes highlighted in this work include the introduction to the basic principles of cyclic voltammetry, the construction of a calibration curve based on the Randles−Sevcik equation, obtaining a linear regression equation using Microsoft excel, acid digestion of drug supplements, and quality assurance through a statistical evaluation of experimental data. This laboratory experiment also emphasizes the advantages of using the method of a standard addition to a single solution.

Phosphorylation is a very important biochemical process in metabolism and biochemical marking. The mechanism for the biophosphorylation of substrates and the hydrolysis/transesterification of RNA has been suggested to proceed through phosphorane intermediates. Although the phosphorane intermediate/transition state has long been a subject of many theoretical models and studies, it has neither been isolated nor characterized, with most information derived from the hydrolysis and radiolabeling of cyclic phosphotriesters. We herein present the first report of the spontaneous phosphorylation of sugars and polyols in the absence of enzymes. That is, aldehydes and ketones combine with inorganic phosphates to form activated phosphates that phosphorylate alcohols without the requirement of any enzyme or additional activating agent. This phosphorylation is particularly favored in polyhydroxycarbonyls that can form internal cyclic acetals to give rise to the corresponding acetal phosphoranes. We have further characterized these phosphoranes and demonstrated their dehydration to the corresponding phosphates by using high-resolution mass spectroscopy. The phosphorylation of adenosine and uridine to form the corresponding phosphoranes was also achieved.

Introduction: Radiology is a technical service that provides medical imaging for all sectors of healthcare. Hospital-acquired infections (HAIs) is a major challenge in radiology and this is exacerbated in contexts where the healthcare system is unable to provide adequate funding and attention to effective infection control measures. The objectives of this study were to audit current cleaning procedures through the observation of practices in a radiology department, and to determine the types and numbers of nosocomial pathogens present on selected radiology imaging equipment and accessories before and after decontamination. Methodology: In phase one we observed seven radiographers to audit cleaning procedures and practices. In phase two we collected swab samples from selected radiology imaging equipment and accessories and then cultured them for identification of microbes. Results: It was observed that radiographers partially practiced infection control measures. This was due to the absence of documented protocol for infection control procedures. Our results indicated that all the selected equipment and accessories were contaminated with microorganisms pre- and post-cleaning. The identified microbes were Staphylococcus aureus, Coagulase negative Staphylococci (CoNS), Bacillus species (spp.), Shigella spp., Shigella sonnei., Klebsiella spp., Salmonella paratyphi A (S. paratyphi A), Salmonella typhi (S. typhi), Providencia rettgeri, Enterobacter spp. and Citrobacter spp. and Methicillin resistant strains of Staphylococcus aureus (MRSA). Conclusions: The research concluded that the recommended cleaning agents did not effectively reduce the number of microorganisms making the selected equipment and accessories fomites for nosocomial pathogens.

Fucosylated chondroitin sulfates are complex polysaccharides extracted from sea cucumber. They have been extensively studied for their anticoagulant properties and have been implicated in other biological activities. While nuclear magnetic resonance spectroscopy has been used to extensively characterize fucosylated chondroitin sulfate oligomers, we herein report the first detailed mass characterization of fucosylated chondroitin sulfate using high-resolution Fourier transform ion cyclotron resonance mass spectrometry. The two species of fucosylated chondroitin sulfates considered for this work include Pearsonothuria graeffei (FCS-Pg) and Isostichopus badionotus (FCS-Ib). Fucosylated chondroitin sulfate oligosaccharides were prepared by N-deacetylation-deaminative cleavage of the two fucosylated chondroitin sulfates and purified by repeated gel filtration. Accurate mass measurements obtained from electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry measurements confirmed the oligomeric nature of these two fucosylated chondroitin sulfate oligosaccharides with each trisaccharide repeating unit averaging four sulfates per trisaccharide. Collision-induced dissociation of efficiently deprotonated molecular ions through Na/H+ exchange proved useful in providing structurally relevant glycosidic and cross-ring product ions, capable of assigning the sulfate modifications on the fucosylated chondroitin sulfate oligomers. Careful examination of the tandem mass spectrometry of both species deferring in the positions of sulfate groups on the fucose residue (FCS-Pg-3,4- OS) and (FCS-Ib-2,4- OS) revealed cross-ring products 0,2Aαf and 2,4X2αf which were diagnostic for (FCS-Pg-3,4- OS) and 0,2X2αf diagnostic for (FCS-Ib-2,4- OS). Mass spectrometry and tandem mass spectrometry data acquired for both species varying in oligomer length (dp3-dp15) are presented.

Heparin is a polysaccharide that is widely used as an anticoagulant drug. The mechanism for heparin’s anticoagulant activity is primarily through its interaction with a serine protease inhibitor, antithrombin III (AT), that enhances its ability to inactivate blood coagulation serine proteases, including thrombin (factor IIa) and factor Xa. The AT-binding site in the heparin is one of the most well-studied carbohydrate-protein binding sites and its structure is the basis for the synthesis of the heparin pentasaccharide drug, fondaparinux. Despite our understanding of the structural requirements for the heparin pentasaccharide AT-binding site, there is a lack of data on the natural variability of these binding sites in heparins extracted from animal tissues. The present work provides a detailed study on the structural variants of the tetrasaccharide fragments of this binding site afforded following treatment of a heparin with heparin lyase II. The 5 most commonly observed tetrasaccharide fragments of the AT-binding site are fully characterized, and a method for their quantification in heparin and low-molecular-weight heparin products is described.

To what extent the effective radius of a nanometer-sized electrode matches its geometric radius is a concern because it is believed that the continuum assumptions of the Nernst−Planck equation do not work when the diameter of the electrode is less than 100 nm. In our research, high-resolution scanning electron microscopy images have been employed to characterize the electrodes whose effective radii have been obtained from electrochemical methods. Thus, electrode geometric and effective dimensions could be compared. Our results show that the geometric radius matches the effective radius very well when the effective radius is larger than 20 nm. There is a significant difference between the effective and the geometric electrode radii when the effective electrode radius is smaller than 20 nm. Current fluctuation can be observed on a 1.6 nm radius electrode at slow scan rates. Possible reasons for the current fluctuation on the electrode are discussed.

The present work focuses on the assignment of uronic acid stereochemistry in heparan sulfate (HS) oligomers. The structural elucidation of HS glycosaminoglycans is the subject of considerable importance due to the biological and biomedical significance of this class of carbohydrates. They are highly heterogeneous due to their non-template biosynthesis. Advances in tandem mass spectrometry activation methods, particularly electron detachment dissociation (EDD), has led to the development of methods to assign sites of sulfo modification in glycosaminoglycan oligomers, but there are few reports of the assignment of uronic acid stereochemistry, necessary to distinguish glucuronic acid (GlcA) from iduronic acid (IdoA). Whereas preceding studies focused on uronic acid epimers with no sulfo modification, the current work extends the assignment of the hexuronic acid stereochemistry to 2-O-sulfo uronic acid epimeric tetrasaccharides. The presence of a 2-O-sulfo group on the central uronic acid was found to greatly influence the formation of B3, C2, Z2, and Y1 ions in glucuronic acid and Y2 and 1,5X2 for iduronic acid. The intensity of these peaks can be combined to yield a diagnostic ratios (DR), which can be used to confidently assign the uronic acid stereochemistry.

Interactions between chemokines such as CCL5 and glycosaminoglycans (GAGs) are essential for creating haptotactic gradients to guide the migration of leukocytes into inflammatory sites, and the GAGs that interact with CCL5 with the highest affinity are heparan sulfates/heparin. The interaction between CCL5 and its receptor on monocytes, CCR1, is mediated through residues Arg-17 and -47 in CCL5, which overlap with the GAG-binding (44)RKNR(47) "BBXB" motifs. Here we report that heparin and tetrasaccharide fragments of heparin are able to inhibit CCL5-CCR1 binding, with IC50 values showing strong dependence on the pattern and extent of sulfation. Modeling of the CCL5-tetrasaccharide complexes suggested that interactions between specific sulfate and carboxylate groups of heparin and residues Arg-17 and -47 of the protein are essential for strong inhibition; tetrasaccharides lacking the specific sulfation pattern were found to preferentially bind CCL5 in positions less favorable for inhibition of the interaction with CCR1. Simulations of a 12-mer heparin fragment bound to CCL5 indicated that the oligosaccharide preferred to interact simultaneously with both (44)RKNR(47) motifs in the CCL5 homodimer and engaged residues Arg-47 and -17 from both chains. Direct engagement of these residues by the longer heparin oligosaccharide provides a rationalization for its effectiveness as an inhibitor of CCL5-CCR1 interaction. In this mode, histidine (His-23) may contribute to CCL5-GAG interactions when the pH drops just below neutral, as occurs during inflammation. Additionally, an examination of the contribution of pH to modulating CCL5-heparin interactions suggested a need for careful interpretation of experimental results when experiments are performed under non-physiological conditions.