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Abstract: Low-molecular-weight (LMW) succinoglycans (monomers, dimers, and trimers) were isolated from Sinorhizobium meliloti 1021 and have been firstly investigated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) using 2,4,6-trihydroxyacetophenone (THAP) as an optimal matrix in the negative ion mode. The main fractions of LMW succinoglycans contain molecules assembled of octasaccharide subunits. MALDI-TOF mass spectra of the LMW succinoglycan monomers, the dimers, and the trimers showed the daughter ions resulting from the losses of the terminal galactose residues at the reducing ends, clearly indicating that the galactosyl linkages are more labile than the other glucosyl linkages. Furthermore, the losses of the acetyl groups as substituents rather than the succinyl and pyruvyl ester linkages by prompt fragmentation primarily occurred during MALDI-TOF analysis, suggesting the greater instability of acetyl linkages compared to pyruvyl and succinyl linkages. [Copyright &y& Elsevier]

Abstract: Shinorhizobial cyclosophoraose (cyclic β-(1→2)-glucan) or succinoglycan monomer (SGM 2), which has one acetyl, pyruvyl, and succinyl group, functions as a morphology-directing agent for the synthesis of pure trigonal selenium nanowires by using ascorbic acid (vitamin C) as the reducing agent. The synthesis was achieved in water at room temperature. Under these experimental conditions, the diameters of the as-prepared Se nanowires were varied in the range of 34–120nm by cyclosophoraose and of 33–66nm by SGM 2, in which the nanowires were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Through this study, we propose that Shinorhizobial cyclic and linear oligosaccharides have morphologically directing functions for the synthesis of single-crystalline selenium nanowires by green chemical methods. [Copyright &y& Elsevier]

Abstract: Zooglan, a weakly acidic exopolysaccharide produced by Zoogloea ramigera 115, catalyzed the preferential methanolysis of phospatidylcholine compared to other phospholipids when the reaction was carried out in pure methanol at 30°C. The reaction was monitored by thin-layer chromatography (TLC) as well as 1H and 31P nuclear magnetic resonance (NMR) spectrometry. Zooglan enhanced the rate of methanolysis of dipalmitoylphosphatidylcholine (DPPC) up to about 170-fold compared to controls such as DPPC alone, pyruvic acid, succinic acid and acetic acid. Furthermore, the methanolysis was different depending on the head groups of the phospholipids. Through this study, we have shown that zooglan can act as an environmentally benign catalytic polysaccharide for methanolysis in pure methanol solution. [Copyright &y& Elsevier]

Abstract: α-Cyclosophorotridecaose (α-C13) produced by Ralstonia solanacearum is isolated by trichloroacetic acid treatment and subjected to various chromatographic techniques. Here, we report for the first time that R. solanacearum produces acetylated α-C13. Structural analyses of the acetylated α-C13 were performed with 1D or 2D NMR spectroscopy, MALDI-TOF MS and HPLC. The results show that the α-C13 is substituted by mainly one acetyl residue at the C-6 position of the glucose unit. [Copyright &y& Elsevier]

Abstract: Some microbial carbohydrates have been used as catalysts for the multicomponent Strecker reaction using trimethylsilyl cyanide (TMSCN). α-Cyclosophorohexadecaose (α-C16) derived from Xanthomonas species and succinoglycan monomers derived from Rhizobium species acted as catalytic carbohydrates in the mixture solutions of methanol and water. Malonaldehyde bis(phenylimine) as a substrate was completely converted (yield: 100%) into its product to 100% by both α-C16 and the succinoglycan monomer (M2), having acetyl, pyruvyl, and succinyl groups as substituents after 1h. The catalytic abilities of the carbohydrates were dependent on the inherent structures of the substrates used in this study, where substrate 1 having a symmetrical structure rather than the others was favorably reacted with the α-C16 and M2. Through this study, we suggest that the microbial carbohydrates used in this study could be expected to be environmentally-benign catalysts for the synthesis of α-aminonitriles. [Copyright &y& Elsevier]

Abstract: Benzoate methanolysis was accelerated by α-cyclosophorohexadecaose (α-C16), which is a neutral cyclic hexadecaglucoside containing fifteen β-(1→2)-linkages and one α-(1→6)-linkage. This α-C16, a periplasmic cyclooligosaccharide isolated from rice pathogenic bacteria, Xanthomonas oryzae, enhanced the methanolysis of three different benzoates (vinyl benzoate, phenyl benzoate, and 4-chlorophenyl benzoate) about 69-fold, 24-fold, and 14-fold comparing with control, respectively. A possible intermediate formed during the reaction was detected on MALDI-TOF spectra. Through this study, we suggest that a microbial cyclic glucan, α-C16, can function as a catalytic carbohydrate for the methanolysis of various ester compounds. [Copyright &y& Elsevier]

Abstract: Zooglan, the acidic exopolysaccharide produced by Zoogloea ramigera functioned as a novel catalytic carbohydrate for methanolysis of 4-benzylidene-2-phenyloxazolone, one of 5(4H)-oxazolones. The conversion rate was enhanced by zooglan with increasing reaction temperature up to 70°C. Zooglan accelerated the conversion about 189-fold for the oxazolone compound comparing with a control at 70°C, when the conversion rate (% conversion/min) was determined at the mid point of the inflection on the curves fitted to the data points measured. Herein, we propose that complex carbohydrates derived from microorganisms, containing zooglan could have potentials as catalysts in specific organic reactions. [Copyright &y& Elsevier]

Carboxymethylated cyclosophoraoses (CM-Cys) were synthesized by chemical modification of a family of neutral cyclosophoraoses isolated from Rhizobium leguminosarum biovar trifolii. Structural analyses of the CM-Cys were carried out using NMR and FTIR spectroscopies, and the molecular weight distributions were confirmed with MALDI-TOF mass spectrometry. Based on structural characterization, native cyclosophoraoses were successfully substituted with carboxymethyl groups at the OH-4 and OH-6 of the glucose residues with degrees of substitution (DS) ranging from 0.012 to 0.290. CM-Cys was also used as a host for the inclusion complexation with hydrobenzoin (HB) and N-acetyltryptophan (N-AcTrp) as guest molecules. NMR spectroscopic analyses of the complexes showed that the CM-Cys induced chemical shifts of some protons of the guest molecules upon the complexation. Phase solubility studies of the guest molecules by CM-Cys were performed using HPLC, and the results were compared with those of native cyclosophoraoses. The solubility of HB and N-AcTrp was enhanced by the CM-Cys about 5.1- and 299-fold, respectively. [Copyright &y& Elsevier]

A novel catalytic methanolysis can be induced by a natural cyclooligosaccharide, a cyclosophoraose (cyclic-(1 → 2)-β-d-glucan, Cys), which is a member of a family of unbranched cyclooligosaccharides produced as intra- or extraoligosaccharides by soil microorganisms of the genus, Rhizobium. Cys catalyzed the methanolysis for 5(4H)-oxazolones and various phospholipids. Cys enhanced the methanolysis reaction about 9200-fold for a benzylidene oxazolone or 250-fold for dipalmitoylphosphatidylcholine comparing with control. In this study, we describe that natural cyclosophoraoses isolated from the Rhizobium species function as catalytic carbohydrates for the methanolysis. [Copyright &y& Elsevier]

Cyclosophoraoses, cyclic β-(1→2)-d-glucans produced by Rhizobium meliloti 2011, were used as a novel chiral additive for the separation of terbutaline, amethopterin, thyroxine and N-acetylphenylalanine enantiomers in aqueous capillary electrophoresis (CE). Enantioseparation took place in the normal- or reversed-polarity mode when a high concentration of neutral (60 mM) or anionic (40 mM) cyclosophoraoses was added to the background electrolyte (BGE). [Copyright &y& Elsevier]

Cyclosophoraoses (cyclic-(1→2)-β-d-glucans) produced by Rhizobium meliloti were used as a novel chiral NMR solvating agent. 13C NMR spectroscopic analysis as an enantiodiscriminating tool was carried out where NMR signal splittings were observed on the interactions of cyclosophoraoses with the enantiomers of N-acetylphenylalanine, catechin and propranolol. The 13C chemical shifts of cyclosophoraoses induced by the enantiomeric interactions predominantly occurred at the C-1 and C-2 carbons associated with the -glycosidic linkage. [Copyright &y& Elsevier]

[Display omitted] • SARS-CoV-2 may mutate in one or more of the target regions of commercial RT-PCR assays. • A novel indel mutation in the viral N gene is a cause of negative results for the N gene in a widely used assay. • The novel deletion is located at variable region of the viral N gene. • Our findings provide an evidence of the viral genetic variability and rapid evolution. Commercially available reverse transcription-polymerase chain reaction (RT-PCR) kits are being used as an important tool to diagnose SARS-CoV-2 infection in clinical laboratories worldwide. However, some kits lack sufficient clinical evaluation due to the need for emergency use caused by the current COVID-19 pandemic. Here we found that a novel insertion/deletion mutation in the nucleocapsid (N) gene of SARS-CoV-2 samples is a cause of negative results for the N gene in a widely used assay that received emergency use authorization (EUA) from US FDA and Conformite Europeenne- in vitro diagnostics (CE-IVD) from EU. Although SARS-CoV-2 is diagnosed positive by other target probes in the assay, our findings provide an evidence of the genetic variability and rapid evolution of SARS-CoV-2 as well as a reference in designing commercial RT-PCR assays. [ABSTRACT FROM AUTHOR]

Abstract: Succinoglycan monomers (M1, M2, and M3) are octasaccharides with acetyl, pyruvyl, and/or succinyl groups as substituents derived from Sinorhizobium meliloti 1021. The dissociation patterns of the octasaccharides caused by low-energy collision-activated dissociation (CAD) were investigated using triple quadrupole tandem mass spectrometry (MS) equipped with an electrospray ionization (ESI) source with increasing collision energy (CE) in negative ion mode. None of the succinoglycan monomers were fragmented at a CE of −25eV. When the CE was applied to −50 or −70eV, the loss of the terminal Gal residue and/or the succinyl group of the monomers was observed in the product ion scan mode. Interestingly, the acetyl and the pyruvyl groups in the succinoglycan monomers were not lost even when a CE of −70eV was applied, indicating that the substituents are more stable than the succinyl group in the octasaccharides. [Copyright &y& Elsevier]

Abstract: Commercially available polysaccharides, agarose and gellan, were used as morphology-directing agents for the synthesis of t-Se nanowires in water at room temperature in the presence of ascorbic acid as reducing agent. The nanostructures were characterized using XRD, SEM, and TEM. The diameter of the nanowires varied from 100 to 208nm for nanowires obtained in the presence of agarose and from 51 to 145nm for nanowires from gellan, as evidenced by SEM and TEM. Agarose and gellan have then a potential as environmentally acceptable morphology-directing agents to generate Se nanostructures in water. [Copyright &y& Elsevier]

Highlights: [•] The purified rhizobial carbohydrates were monofuntionalized with biotin tag. [•] The biotinylated cyclic β-glucans were synthesized through four steps. [•] Succinoglycans and monomers were biotinylated at the reducing sugar with one step. [•] The prepared neoglycoconjugate will be solid probes for study on symbiotic activity. [Copyright &y& Elsevier]

Abstract: Objective: To compare the levels of urinary excretion of nephrin in women experiencing either normotensive or severe preeclamptic pregnancies, and to examine the relationship between urinary nephrin levels and clinical parameters of preeclampsia. Study design: In a case control study we collected serum and urine specimens from women with normal pregnancy (n =30) and from women with severe preeclampsia (n =43). Serum nephrin levels and urinary nephrin concentrations were measured in all patients. Results: Both serum and urine concentrations of nephrin were significantly higher in the severe preeclamptic group than in the normal pregnancy group. In addition, we identified a significant relationship between urinary nephrin levels and urine protein concentrations in the severe preeclamptic group. Urine nephrin concentrations were also correlated with serum creatinine levels and with diastolic blood pressure in the severe preeclamptic group. Conclusion: The positive correlations observed in this study suggest that urinary nephrin excretion might play an important role in the pathogenesis of proteinuria during preeclampsia and could be a good indicator of renal damage. [Copyright &y& Elsevier]

Abstract: The pH-dependent inclusion complexation of carboxymethylated cyclosophoraoses (CM-Cys) with N-acetylphenylalanine was investigated. The CM-Cys were synthesized through chemical modification of cyclosophoraoses, cyclic-(1→2)-β-d-glucans produced by Rhizobium meliloti 2011. The study was conducted by ultraviolet-visible (UV–vis) and nuclear magnetic resonance (NMR) spectroscopic analyses. A continuous variation plot based on the UV–vis spectroscopic analysis reveals that the inclusion complexes have a predominantly 1:1 stoichiometry. The NMR studies, which include a two-dimensional rotating frame nuclear Overhauser effect spectroscopy (ROESY) technique, show that the complexes of CM-Cys with N-acetylphenylalanine exist with different inclusion structures at pH 3 and 7. Furthermore, the NMR titration study shows that the inclusion complexes kept the pH-dependent binding constants (K b), based on the Benesi–Hildebrand procedure, K b to be 189±6M−1 for pH 7 and 100±12M−1 for pH 3. Given that the pH-dependent changes of binding positions in the CM-Cys is due to the differential charge distribution of the carboxyl groups within the CM-Cys, these results suggest that the CM-Cys could regulate the efficiency of the inclusion complexation corresponding to the external pH change. Simulated annealing molecular dynamics simulations (SA-MD) were also performed to discuss the pH-dependent conformational change of CM-Cys. [Copyright &y& Elsevier]