Facile One‐Step Syntheses of Modified O‐Glycoprotein Galβ1‐3GalNAc Structures by Transglycosylation Employing Three β‐Galactosidases from Bovine Testes,Xanthomonas manihotis,and Bacillus circulans *

Natural O‐glycoproteins such as the Thomsen‐Friedenreich antigen or gangliosides contain the motif Galβ1‐3GalNAc as an important disaccharide with significant biologic activity. The arrangement of spatial functionalities in this structure are of particular interest with regard to the development of potential leads en route to pharmaceuticals. Therefore, it was desired to obtain access to a range of modified derivatives of the aforementioned motif paying particular attention to introducing specific deoxy functions instead of hydroxyl groups.     

Infinitesimal 2-braidings and differential crossed modules

We categorify the notion of an infinitesimal braiding in a linear strict symmetric monoidal category, leading to the notion of a (strict) infinitesimal 2-braiding in a linear symmetric strict monoidal 2-category. We describe the associated categorification of the 4-term relations, leading to six categorified relations. We prove that any infinitesimal 2-braiding gives rise to a flat and fake flat 2-connection in the configuration space of n particles in the complex plane, hence to a categorification of the Knizhnik–Zamolodchikov connection. We discuss infinitesimal 2-braidings in a certain monoidal 2-category naturally assigned to every differential crossed module, leading to the notion of a symmetric quasi-invariant tensor in a differential crossed module. Finally, we prove that symmetric quasi-invariant tensors exist in the differential crossed module associated to Wagemann's version of the String Lie-2-algebra. As a corollary, we obtain a more conceptual proof of the flatness of a previously constructed categorified Knizhnik–Zamolodchikov connection with values in the String Lie-2-algebra.     

On string topology of classifying spaces

Let G be a compact Lie group. By work of Chataur and Menichi, the homology of the space of free loops in the classifying space of G is known to be the value on the circle in a homological conformal field theory. This means in particular that it admits operations parameterized by homology classes of classifying spaces of diffeomorphism groups of surfaces. Here we present a radical extension of this result, giving a new construction in which diffeomorphisms are replaced with homotopy equivalences, and surfaces with boundary are replaced with arbitrary spaces homotopy equivalent to finite graphs. The result is a novel kind of field theory which is related to both the diffeomorphism groups of surfaces and the automorphism groups of free groups with boundaries. Our work shows that the algebraic structures in string topology of classifying spaces can be brought into line with, and in fact far exceed, those available in string topology of manifolds. For simplicity, we restrict to the characteristic 2 case. The generalization to arbitrary characteristic will be addressed in a subsequent paper.     

A rapid and effective method for silver staining of PCR products separated in polyacrylamide gels

With the development of molecular quantitative genetics, particularly, genetic linkage map construction, quantitative trait loci mapping or genes fine mapping and association analysis etc., more and more PCR products separated in polyacrylamide gels need to be silver‐stained. However, conventional silver‐staining procedures are complicated and time‐consuming as they require a lot of preparation and handling of several solutions prior to use. In this study, a simple and rapid protocol for silver staining of PCR products was developed. The number of steps was reduced compared to conventional protocols, thus achieving detection of PCR products in 7 min, saving time and resources. Fixation and staining solution and developing solution in present staining procedure allowed a reutilization for 12 and 8 times, respectively, reducing the cost greatly. Meanwhile, the sensitivity was significantly improved with the improved method and the minimum of 0.097 ng/μL of DNA amount can be detected in denaturing polyacrylamide gel. The protocol developed in this study will facilitate the development of molecular quantitative genetics.     

Characterization of the potential energy surfaces of two small but challenging noncovalent dimers: (P2)2 and (PCCP)2

This work characterizes eight stationary points of the P₂ dimer and six stationary points of the PCCP dimer, including a newly identified minimum on both potential energy surfaces. Full geometry optimizations and corresponding harmonic vibrational frequencies were computed with the second‐order Møller–Plesset (MP2) electronic structure method and six different basis sets: aug‐cc‐pVXZ, aug‐cc‐pV(X+d)Z, and aug‐cc‐pCVXZ where X = T, Q. A new L‐shaped structure with C₂ symmetry is the only minimum for the P₂ dimer at the MP2 level of theory with these basis sets. The previously reported parallel‐slipped structure with C_2h symmetry and a newly identified cross configuration with D₂ symmetry are the only minima for the PCCP dimer. Single point energies were also computed using the canonical MP2 and CCSD(T) methods as well as the explicitly correlated MP2‐F12 and CCSD(T)‐F12 methods and the aug‐cc‐pVXZ (X = D, T, Q, 5) basis sets. The energetics obtained with the explicitly correlated methods were very similar to the canonical results for the larger basis sets. Extrapolations were performed to estimate the complete basis set (CBS) limit MP2 and CCSD(T) binding energies. MP2 and MP2‐F12 significantly overbind the P₂ and PCCP dimers relative to the CCSD(T) and CCSD(T)‐F12 binding energies by as much as 1.5 kcal mol^?1 for the former and 5.0 kcal mol^?1 for the latter at the CBS limit. The dominant attractive component of the interaction energy for each dimer configuration was dispersion according to several symmetry‐adapted perturbation theory analyses. © 2014 Wiley Periodicals, Inc.     

Electronic structure and thermochemistry for monocarbides MC,MC+ and MC− (M=Zn,Cd, Hg): CCSD(T) and DFT works

In this work, the ab-initio coupled cluster CCSD(T) method and the B3LYP, BP91W and CAM-B3LYP functional of DFT method in conjunction with the aug-cc-pVTZ-PP basis have been applied to study the group 12 monocarbides MC, MC⁺ and MC^?. The potential energy curves (PECs) for the three electronic states ³Σ^?, ⁵Σ^? and ¹Δ of the MC and the two states ²∑^- and ⁴∑^- for the MC⁺ cations and MC^? anions have been investigated. In addition, Bond distance Re, transition energy Te, vibrational frequency ω_e, ionization energy IE, electron affinity EA, dipole moment μ, dissociation energy D₀ and heat formation ΔH°f₀/ΔH°f₂₉₈, were determined for each species. The analysis of the dissociation energy for ZnC, CdC and HgC shows the decrease in the stability of the monocarbides from Zn to Hg. For ΔH°f₀/ΔH°f₂₉₈ values of MC, which are not known experimentally or theoretically, we recommend the following CCSD(T) predictions of ZnC, CdC and HgC: 181.3/178.54, 180.65/178.4 and 175.35/174.71 kcal/mol respectively. Comparing the three functionals with the CCSD(T) results, the CAM-B3LYP functional shows excellent predictive agreement for the various properties of the group 12 monocarbides.     

Synergistic effect of Thiourea and HCl on Palladium (II) recovery: An investigation on Chemical structures and thermodynamic stability via DFT

This work duly investigates the recovery of Pd (II) chlorocomplexes from industrial wastewater. Chemical structures and thermodynamic stabilities of the complex formed are evaluated via density functional theory (DFT). By applying synergistic solutions of thiourea mixed with hydrochloric acid (HCl), the stripping reaction of Pd (II) in the loaded Aliquat 336 occurs and Pd (II) chlorocomplexes coordinated thiourea ligands are formed, thus 80.19% of Pd (II) chlorocomplexes can be recovered. The aim of this study is to gain a better understanding of the stripping mechanisms and the structure of the complexes formed via the synergistic system. Such an understanding is still limited since little research has been conducted in this field. Owing to their molecular geometry, ligand coordination and donor groups play a vital role in the reactivity of palladium (II) complex. Quantum models have been developed to evaluate the chemical structure and thermodynamics stability of ((NH₂)₂CS·PdCl₂) namely: (i) DFT with B3LYP/6-31g(d,p) and MP2/6-31g(d,p) basis set, (ii) MP2 with cc-pVTZ basis set and (iii) CCSD(T)/cc-pVTZ. Results demonstrate that the highest geometric stability exhibited is the structure of Pd-S bonding with 180° Cl-Pd-Cl. The distance (r) and angle (a) of the selected geometrical parameters for (NH₂)₂CS·PdCl₂ complex are reported. Additionally, FTIR and UV–vis spectroscopies have been conducted to analyze the sampling solutions. Further, the calculated vibrational frequencies and experimental spectroscopic results show good agreement with the optimized geometry.     

Development of Novel Isoindolone-Based Compounds against Trypanosoma brucei rhodesiense

This study identified the isoindolone ring as a scaffold for novel agents against Trypanosoma brucei rhodesiense and explored the structure-activity relationships of various aromatic ring substitutions. The compounds were evaluated in an integrated in vitro screen. Eight compounds exhibited selective activity against T. b. rhodesiense (IC₅₀<2.2 μm ) with no detectable side activity against T. cruzi and Leishmania infantum. Compound 20 showed low nanomolar potency against T. b. rhodesiense (IC₅₀=40 nm ) and no toxicity against MRC-5 and PMM cell lines and may be regarded as a new lead template for agents against T. b. rhodesiense. The isoindolone-based compounds have the potential to progress into lead optimization in view of their highly selective in vitro potency, absence of cytotoxicity and acceptable metabolic stability. However, the solubility of the compounds represents a limiting factor that should be addressed to improve the physicochemical properties that are required to proceed further in the development of in vivo-active derivatives.     

Crassolide Suppresses Dendritic Cell Maturation and Attenuates Experimental Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease characterized by the production of β2-glycoprotein I (β2GPI)-dependent autoantibodies, with vascular thrombosis or obstetrical complications. Around 20% of APS patients are refractory to current treatments. Crassolide, a cembranoid diterpene extracted from soft corals, is a potential therapeutic candidate. Here, to examine the anti-inflammatory properties of crassolide, we first determined its effects on bone marrow-derived and splenic dendritic cells (DC). Specifically, we applied lipopolysaccharide (LPS) or β2GPI stimulation and measured the expressions of CD80 and CD86, and secretions of cytokines. We also determined in the OT-II mice, if bone marrow-derived DC was able to stimulate antigen-specific T cells. Moreover, we examined the therapeutic potential of crassolide postimmunization in a murine model of APS that depended on active immunization with β2GPI. The vascular manifestations were evaluated in terms of fluorescein-induced thrombi in mesenteric microvessels, whereas the obstetric manifestations were evaluated based on the proportion of fetal loss after pregnancy. We also measured blood titers of anti-β2GPI antibody, splenic cell proliferative responses and cytokine secretions after β2GPI stimulation ex vivo. Finally, we determined in these mice, hematological, hepatic and renal toxicities of crassolide. Crassolide after LPS stimulation suppressed DC maturation and secretion of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-12 and IL-23, and downstream T cell activation. Crassolide could partially ameliorate both the vascular and obstetric manifestations of APS in BALB/c mice. Both blood titers of anti-β2GPI antibody and splenic cell proliferation after β2GPI stimulation were reduced. Splenic Th1 and Th17 responses were also lowered after β2GPI stimulation. Finally, within therapeutic doses of crassolide, we found no evidence of its toxicity. In conclusion, we showed the ability of crassolide to suppress DC and downstream T cell responses. Crassolide is therefore a potential candidate for adjunctive therapy in APS.     

A Label-Free Fluorometric Glutathione Assay Based on a Conformational Switch of G-quadruplex

In this paper, a label-free fluorescent method for glutathione (GSH) detection based on a thioflavin T/G-quadruplex conformational switch is developed. The sensing assay is fabricated depending on the virtue of mercury ions to form a thymine–thymine mismatch, which collapses the distance between two ssDNA and directs the guanine-rich part to form an intra-strand asymmetric split G-quadruplex. The newly formed G-quadruplex efficiently reacts with thioflavin T and enhances the fluorescent intensity. In the presence of GSH, Hg²⁺ is absorbed, destroying the G-quadruplex formation with a significant decrease in fluorescence emission. The proposed fluorescent assay exhibits a linear range between 0.03–5 μM of GSH with a detection limit of 9.8 nM. Furthermore, the efficacy of this method is examined using human serum samples to detect GSH. Besides GSH, other amino acids are also investigated in standard samples, which display satisfactory sensitivity and selectivity. Above all, we develop a method with features including potentiality, facility, sensitivity, and selectivity for analyzing GSH for clinical diagnostics.