A fungal-modified material with high uranium (VI) adsorption capacity and strong anti-interference ability.

With open-chain polyether as the bridge chain, a new fungal-modified material with diamidoxime groups was prepared by a series of uncomplex synthesis reaction. The orthogonal experiment obtained its optimized adsorption conditions as follows: the initial pH value of 6.5, the initial uranyl concentration of 40 mg L-1, the contact time of 130 min, and the a solid-liquid ratio of 25 mg L-1. The maximum adsorption capacity of target material was 446.20 mg g-1, and it was much greater than that of the similar monoamidoxime material (295.48 mg g-1). The linear Langmuir (R2 = 0.9856) isotherm models and the linear pseudo-second-order kinetic model (R2 = 0.9931) fit the experimental data of uranium (VI) adsorption better, indicating the adsorption mechanism should mainly be the monolayer adsorption and chemical process. In addition, the relevant experiments exhibited the prepared material had the good reusability, which reached 84.25% of the maximum capacity after five cycles, and the excellent anti-interference performance. The above features suggest the modified fungus material will have the good application prospect in the future.

Synthesis, Biological Evaluation, and Docking Studies of Open-Chain Carbohydrate Amides as Acetylcholinesterase Inhibitors.

INTRODUCTION: Alzheimer's disease is a multifactorial syndrome, which is not yet fully understood, causing memory loss, dementia, and, ultimately, death. Acetylcholinesterase inhibitors are the mainstay drugs that are used in disease-symptomatic treatment. In this work, we report a new synthetic route yielding sugar amides as low to moderate acetylcholinesterase inhibitors. METHODS: Commercially available diacetone glucose was converted into perbenzyl D-glucono-1,4- lactone, which reacted with aromatic or aliphatic amines to afford the corresponding new amides in a high isolated yield. Docking studies of the most promising hydroxybutylamide and benzylamide were performed to assign binding interactions with acetylcholinesterase and determine the key features for bioactivity. RESULTS: The inhibitors are accommodated in enzyme gorge, blocking the access to Ser203 mainly due to π-π stacking interactions of sugar benzyl groups with the aromatic gorge residues, Tyr337 and Tyr341 for both inhibitors and Trp439 only for the hydroxybutylamide. CONCLUSION: Bonding is also significant through sugar interaction with the residues Tyr124 and Ser125-OH in both inhibitors. Flexibility of these open-chain structures seems to be quite relevant for the observed binding to acetylcholinesterase.

Characterizing healthy knee symmetry using the finite helical axis and muscle power during open and closed chain tasks.

Understanding healthy joint movement and muscle control, and injurious alterations, is important to determine musculoskeletal contributions to post-injury joint instabilities or altered dynamic joint function. The contralateral limb is often used as a point of reference to determine the effects of knee joint injury. However, it is currently difficult to interpret within subject variability between limbs as this is not well established in the healthy population. There is a continuing need to characterize healthy knee joint mechanics and neuromuscular control to determine the degree of symmetry within healthy individuals. The current study quantified limb symmetry in healthy individuals using the finite helical axis with a unique reference position (rFHA) and electromyography (EMG) approaches, for a closed-chain single leg squat (SLS) and an open-chain seated leg swing. Muscle power and FHA translation, orientation and dispersion were similar between limbs. However, the FHA was located significantly more anterior in the dominant limb relative to the contralateral during both tasks. These between-limb differences in FHA location could be attributed to differences in joint geometry and strength between limbs. This finding provides evidence that healthy knees have asymmetries which have implications for selection of control limbs in studies comparing conditions within and between individuals. Differences identified in dynamic joint function between tasks suggest that the SLS is useful for revealing joint asymmetries due to altered muscular control strategies, while the swing task is expected to highlight asymmetries in joint motion due to altered knee structures following injury.

Proximity channeling during cyanobacterial phycoerythrobilin synthesis.

Substrate channeling is a widespread mechanism in metabolic pathways to avoid decomposition of unstable intermediates, competing reactions, and to accelerate catalytic turnover. During the biosynthesis of light-harvesting phycobilins in cyanobacteria, two members of the ferredoxin-dependent bilin reductases are involved in the reduction of the open-chain tetrapyrrole biliverdin IXα to the pink pigment phycoerythrobilin. The first reaction is catalyzed by 15,16-dihydrobiliverdin:ferredoxin oxidoreductase and produces the unstable intermediate 15,16-dihydrobiliverdin (DHBV). This intermediate is subsequently converted by phycoerythrobilin:ferredoxin oxidoreductase to the final product phycoerythrobilin. Although substrate channeling has been postulated already a decade ago, detailed experimental evidence was missing. Using a new on-column assay employing immobilized enzyme in combination with UV-Vis and fluorescence spectroscopy revealed that both enzymes transiently interact and that transfer of the intermediate is facilitated by a significantly higher binding affinity of DHBV toward phycoerythrobilin:ferredoxin oxidoreductase. Concluding from the presented data, the intermediate DHBV is transferred via proximity channeling.

Evolution and molecular mechanism of four-electron reducing ferredoxin-dependent bilin reductases from oceanic phages.

Ferredoxin-dependent bilin reductases (FDBRs) are a class of enzymes reducing the heme metabolite biliverdin IXα (BV) to form open-chain tetrapyrroles used for light-perception and light-harvesting in photosynthetic organisms. Thus far, seven FDBR families have been identified, each catalysing a distinct reaction and either transferring two or four electrons from ferredoxin onto the substrate. The newest addition to the family is PcyX, originally identified from metagenomics data derived from phage. Phylogenetically, PcyA is the closest relative catalysing the reduction of BV to phycocyanobilin. PcyX, however, converts the same substrate to phycoerythrobilin, resembling the reaction catalysed by cyanophage PebS. Within this study, we aimed at understanding the evolution of catalytic activities within FDBRs using PcyX as an example. Additional members of the PcyX clade and a remote member of the PcyA family were investigated to gain insights into catalysis. Biochemical data in combination with the PcyX crystal structure revealed that a conserved aspartate-histidine pair is critical for activity. Interestingly, the same residues are part of a catalytic Asp-His-Glu triad in PcyA, including an additional Glu. While this Glu residue is replaced by Asp in PcyX, it is not involved in catalysis. Substitution back to a Glu failed to convert PcyX to a PcyA. Therefore, the change in regiospecificity is not only caused by individual catalytic amino acid residues. Rather the combination of the architecture of the active site with the positioning of the substrate triggers specific proton transfer yielding the individual phycobilin products. ENZYMES: Suggested EC number for PcyX: 1.3.7.6 DATABASES: The PcyX X-ray structure was deposited in the PDB with the accession code 5OWG.

Immediate Effects of Lower Limb with Open Chain Weight-adding on Joint Position Sense and Gait Symmetry in Stroke Patients / 中国康复理论与实践

Objective To investigate the immediate effects of lower limb with open chain weight-adding on joint position sense and gait symmetry in stroke patients. Methods From January, 2016 to January, 2017, 39 stroke patients were included. Their joint position sense and gait symmetry were compared before and after weight-adding. The joint position senses of active reproduction of active positioning (ARAP) and passive reproduction of passive positioning (PRPP) were assessed during lower limb straight leg raise. The gait symmetry was also as-sessed and three indexes were recorded including the symmetry of foot rotation angle, step length and percentage of single leg support phase. Results After weight-adding, the position sense of PRPP did not improve (t=0.832, P=0.832), nor of the symmetry of foot rotation an-gle (t=-0.704, P=0.483) and percentage of single leg support phase (t=0.381, P=0.702);the position sense of ARAP improved (t=3.158, P=0.011), as well as the symmetry of step length (t=2.022, P=0.041). Conclusion The lower limb with open chain weight-adding could im-prove the active joint position sense and symmetry of step length.

Polyoxypregnane steroids with an open-chain sugar moiety from Marsdenia tenacissima and their chemoresistance reversal activity.

A polyoxypregnane aglycone, 12ß-O-acetyl-11α-O-isobutyryltenacigenin B, and four polyoxypregnane glycosides with a pachybionic acid ester moiety, 12ß-O-acetyl-3-O-(6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-ß-D-oleandronyl)-11α-O-isobutyryltenacigenin B, 12ß-O-acetyl-3-O-(6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-ß-D-oleandronyl)-11α-O-tigloyltenacigenin B, 12ß-O-acetyl-3-O-(6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-ß-D-oleandronyl)-11α-O-2-methylbutyryltenacigenin B, and 12ß-O-acetyl-3-O-(ß-D-glucopyranosyl-(1→4)-6-deoxy-3-O-methyl-ß-D-allopyranosyl-(1→4)-D-oleandronyl)-11α-O-tigloyltenacigenin B, were isolated from the canes of Marsdenia tenacissima, together with a disaccharide derivative. Their structures were elucidated by extensive spectroscopic analysis, and the absolute configurations were further determined by X-ray crystallographic analysis. With the exception of the disaccharide derivative, all five compounds are unusual naturally occurring polyoxypregnane glycosides bearing an open-chain sugar moiety. Two of these exhibit a wide spectrum of chemoresistance reversal activity, and potential mechanisms were studied accordingly.

Stereochemical behavior of geminal and vicinal 77Se-13C spin-spin coupling constants studied at the SOPPA(CC2) level taking into account relativistic corrections.

A systematic theoretical study of geminal and vicinal (77)Se-(13)C spin-spin coupling constants in the series of the open-chain selenides and selenium-containing heterocycles revealed that relativistic effects play an essential role in the selenium-carbon coupling mechanism, especially when the coupling pathway includes a triple bond, contributing to about 10-15% of their total values and noticeably improving the agreement of the calculated couplings with experiment. Both geminal and vicinal (77)Se-(13)C spin-spin coupling constants show marked stereochemical behavior as documented by their calculated dihedral angle dependence that could be used as a practical guide in stereochemical studies of organoselenium compounds.

Comparison of the clinical effects of open and closed chain exercises after medial patellofemoral ligament reconstruction.

[Purpose] To compare the effects of open-chain exercise (OCE) and closed-chain exercise (CCE) for patients after medial patellofemoral ligament (MPFL) reconstruction. [Subjects and Methods] Forty patients after MPFL reconstruction were randomly divided into an OCE group and a CCE group. All the patients were evaluated at four different time points. [Results] The mean change of thigh circumference decrease in the CCE group was lower than that in the OCE group at both the 3rd and 6th month after surgery. The Lysholm score of the CCE group was higher than that of the OCE group at both the 3rd and 6th month. At the 3rd month after surgery, the visual analog scale score of the CCE group was lower than that of the OCE group. [Conclusion] CCE is better than OCE for both short and long term outcomes of patients after MPFL reconstruction.

Full four-component relativistic calculations of the one-bond 77Se-13C spin-spin coupling constants in the series of selenium heterocycles and their parent open-chain selenides.

Four-component relativistic calculations of (77)Se-(13)C spin-spin coupling constants have been performed in the series of selenium heterocycles and their parent open-chain selenides. It has been found that relativistic effects play an essential role in the selenium-carbon coupling mechanism and could result in a contribution of as much as 15-25% of the total values of the one-bond selenium-carbon spin-spin coupling constants. In the overall contribution of the relativistic effects to the total values of (1)J(Se,C), the scalar relativistic corrections (negative in sign) by far dominate over the spin-orbit ones (positive in sign), the latter being of less than 5%, as compared to the former (ca 20%). A combination of nonrelativistic second-order polarization propagator approach (CC2) with the four-component relativistic density functional theory scheme is recommended as a versatile tool for the calculation of (1)J(Se,C). Solvent effects in the values of (1)J(Se,C) calculated within the polarizable continuum model for the solvents with different dielectric constants (ε 2.2-78.4) are next to negligible decreasing negative (1)J(Se,C) in absolute value by only about 1 Hz. The use of the locally dense basis set approach applied herewith for the calculation of (77)Se-(13)C spin-spin coupling constants is fully justified resulting in a dramatic decrease in computational cost with only 0.1-0.2-Hz loss of accuracy.

QSAR study and molecular design of open-chain enaminones as anticonvulsant agents.

Present work employs the QSAR formalism to predict the ED(50) anticonvulsant activity of ringed-enaminones, in order to apply these relationships for the prediction of unknown open-chain compounds containing the same types of functional groups in their molecular structure. Two different modeling approaches are applied with the purpose of comparing the consistency of our results: (a) the search of molecular descriptors via multivariable linear regressions; and (b) the calculation of flexible descriptors with the CORAL (CORrelation And Logic) program. Among the results found, we propose some potent candidate open-chain enaminones having ED(50) values lower than 10 mg·kg(-1) for corresponding pharmacological studies. These compounds are classified as Class 1 and Class 2 according to the Anticonvulsant Selection Project.