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Abstract Immunoparalysis is an important pathological mechanism in sepsis. However, an effective small molecule therapy is lacking. Here, we show that ouabain, a Na+,K+‐ATPase ligand, can reverse immunoparalysis in vitro, in vivo, and in clinical samples. Notably, the effect of ouabain was critically dependent on TNF‐α expression. However, ouabain had opposing effects on the stability of TNF‐α mRNA: Ouabain triggered miR‐181 transcription, which promoted TNF‐α mRNA degradation and induced immunoparalysis, and ouabain triggered the nuclear export of human antigen R (HuR), which stabilized TNF‐α mRNA and suppressed immuno‐paralysis. Interestingly, because the miR‐181 binding site is located within the HuR binding site in the 3′‐untranslated region of TNF‐α, in ouabain‐treated cells, HuR competed with miR‐181 for binding to TNF‐α mRNA and recruited TNF‐α mRNA to stress granules, thereby stabilizing TNF‐α mRNA and reversing immunoparalysis. Ouabain also induced GM‐CSF and interferon‐γ expression in a HuR‐dependent manner. Hence, the fine‐tuning of TNF‐α mRNA stability by HuR and miR181 plays a crucial role in immunoparalysis, and Na+,K+‐ATPase ligands are promising agents for immunoparalysis therapy.

High purity polysaccharide of pachyman was isolated from the powder of Poria cocos sclerotium with a yield of 77.8%. The intrinsic viscosity of polysaccharide was found to be 78.95 mL/g in DMSO solution at 25°C. The isolated polysaccharide was reacted with chlorosulfonic acid to obtain pachyman sulfate using the improved Wolfrom method. The results of the orthogonality experiment on the sulfation reaction identified that the effectiveness of the reaction conditions on the degree of sulfation and the value of intrinsic viscosity is in the following order: molar ratio of chlorosulfonic acid to glucoside (3–5) > reaction temperature (60–80°C) > reaction time (1–2 h). The kinetic studies of the pachyman sulfation indicated that the hydrolysis is accompanied with the sulfation process. The decrease in intrinsic viscosity of the sulfated pachyman is proportional to the increase in the degree of sulfation under the mild reaction conditions of < 80°C, chlorosulfonic acid/glucoside mole ratio < 5, and reaction time < 2 h. Beyond the above reaction conditions, excessive loss of –OH group occurs during hydrolysis. The NMR results indicated a complete sulfation on C-6 and a partial sulfation on the C-2 and C-4 of glucoside. [ABSTRACT FROM AUTHOR]

Enzyme reaction has been accepted widely in numerous applications owing to the high efficiency and stereo-selectivity, as well as simple preparation by gene engineering. However, the fragility and complex purification process of the enzyme are long-standing problems which limit the large-scale application. One possible solution may be the enzyme immobilization. As one type of porous material with high loading capacity and designable functionality, Metal-Organic Frameworks (MOFs) are ideal choices for the immobilization of enzyme with a considerable interest in recent years. In this study, d-amino acid transaminase (DAT), an important enzyme for industrial synthesis of d-Ala, was covalently immobilized on the surface of a star MOFs material, UiO-66-NH 2. Interestingly, we found that the nanoscale hybrid enzyme UiO-66-NH 2 -Gd-DAT not only maintained the high catalytic efficiency but also got rid of the interference of polluting enzymes, which meant that we could obtain efficient and stereo-selective immobilized enzyme without complex purification process. In general, our findings demonstrated that using UiO-66-NH 2 might be a promising strategy to immobilize enzyme and produce effective biocatalyst with high activity and stereo-selectivity., Competing Interests: Declaration of competing interest All authors declare that there are no conflicts of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Urea derivatives have been widely used in biology and medicine. The substituted urea derivative URD12 introduced in this study exhibits cytotoxic activity against the K562 human leukemia and KB human mouth epidermal carcinoma cell lines. To further study the bioactivity of URD12 and examine its feasibility as a new antitumor drug, we applied in vivo and in vitro assays to investigate the antitumor activity of URD12. URD12 was prepared and its cytotoxicity was evaluated using the BGC-823 human gastric carcinoma, MGC-803 human gastric carcinoma, SMMC-7721 human hepatoma and HepG2 human hepatocellular carcinoma cell lines using MTT assays. Antitumor activity in vivo was confirmed in mice bearing H22 hepatocellular carcinoma cells. Organ coefficient was used to further elucidate the cytotoxic mechanisms of URD12. URD12 inhibited the growth of tested tumor cell lines in vitro and the growth of H22 mouse hepatocellular carcinoma in vivo with no effects on the weight, spleen and thymus coefficient of tumor-bearing mice. In conclusion, our findings indicate that URD12 is an effective antitumor agent without evident immunosuppression effects.

Fluorescence spectroscopy was used to investigate the influences of carbon nanotubes (CNTs) on the fluorescence of bovine serum albumin (BSA), the influences of CNTs on that of gatifloxacin (GFLX), and the influences of GFLX on that of BSA with or without coexisting CNTs under imitated physiological condition. The experimental results demonstrate that both gatifloxacin and carbon nanotubes could quench the intrinsic fluorescence of BSA, and the quenching mechanism is mainly static quenching. The fluorescence quenching action of GFLX on BSA was weakened in the presence of CNTs. The fluorescence quenching data were analyzed according to Stern-Volmer equation and double-reciprocal Lineweaver-Burk equation. It was shown that the quenching constant (K(sv)) and the binding constant (K) are decreased with the concentration of carbon nanotubes increasing. The effects of coexisting CNTs on GFLX-BSA interactions were discussed to offer a reference for the studies on the action mechanism of CNTs or GFLX with albumins in vivo.

The mechanism of color changes of sodium dodecyl sulphate(SDS) and Azur A (AA) before micelle formation was studied by spectral probe. The changes in the absorption spectra of SDS-AA and chondroitin sulfate(CS)-AA complexes were compared. The influence of ethanol and NaCl on the absorption spectra of SDS-AA complex was investigated. It was found that SDS-AA system showed color changes from blue to amaranth to blue due to the difference in the spatial orientation aggregative degree of AA binding on SDS regular aggregate. The critical concentration of premicelle formation (CPC) was found to be 1.0 x 10(-4) mol x L(-1) by the relation between c(SDS) and deltaA498/deltac(SDS).

On binding to deoxyribonucleic acid, the complex of terbium-ciprofloxacin (Tb(3+)-CIP) increases its fluorescence quantum efficiency. Based on this, an easy, rapid and sensitive method for the determination of DNA was developed. Like ethidium bromide (EB), the complex can be intercalated into DNA bases, but it is non-poisonous. Determination can be made at pH 7.0, where the native structure of DNA is not disrupted. The maximum emission is at 545 nm with excitation at 325 nm. This method has good sensitivity (2.8 x 10(-9) mol x L(-1) of ctDNA), high selectivity and a wide linear range (4.3 x 10(-7)-3. 0 x 10(-5) mol x L(-1) of ctDNA). This complex was also employed for the clinical examination of DNA in whole blood of tumor patients. Ten tumor patients and 10 normal persons were enrolled in this study. It was showed that significant difference existed between control group and tumor group (p < 0.05).

Using lomefloxacin-terbium as a fluorescent probe, the interaction of LFLX-Tb3+ and bovine serum albumin (BSA) was investigated by fluorescence spectra. The interaction of LFLX and BSA is quite strong. LFLX can affect the conformation of BSA to some degree. Meanwhile, the electrostatic binding of the BSA with Tb3+ in LFLX-Tb3+ complex could decease the nonradiative energy loss through O-H vibration of H2O molecule in Tb3+ complex. Under the optimum conditions, BSA can enhance the fluorescence intensity of the lomefloxacin-terbium complex at 545 nm, and the enhanced fluorescence intensity of Tb3+ is proportional to the concentration of BSA. Based on that, a new method is constructed for the determination of BSA. The linear ranges for BSA are 16.5-148.5 microg x mL(-1) with a detection limit of 68.8 ng x mL(-1) and relative standard deviations of 1.4%. This method is simple, practical and relatively free of interference from coexistent substances.

The interaction of bovine serum albumin (BSA), sodium dodecyl sulphate (SDS) and Azur A(AA) was studied by spectral probe. The influence of the molar ratio of SDS/BSA on the absorption spectra of BSA-SDS-AA complex was investigated. It was found that the new absorption peak and color changes generated by BSA-SDS-AA complex arose from the difference in the spatial orientation aggregative degree of AA binding on BSA-SDS-AA complex.

In order to understand the mechanism of the interaction of sulfate polysaccharides and small molecules at molecular level, the structure of pachymaran was decorated by Wolfrom, and sulfation pachymaran (SP) was prepared. The maximum binding number (N = 54) and the binding equilibrium constant (K = 1.563 x 10(6)) of the sulfation pachymaran and methylene blue (MB) were obtained by the exoterica model. The influence of the molar ratio of MB/SP, ethanol, hydroxypropyl-beta-cyclodextrin, Triton X-100 and NaCl on the spectra of MB-SP complex was investigated. The mechanism of the color changes of methylene blue and sulfation pachymaran reaction system has been discussed. The authors draw the conclusion that the color changes result mainly from the hydrophobic interaction between methylene blue molecules binding on sulfation pachymaran on the base of the electrostatic interaction of methylene blue and sulfation pachymaran.

The spatial orientation interaction mechanism of chondroitin sulfate (CS) and azure A (AA) was studied by spectrometry. The maximum binding number (N = 151) and the binding equilibrium constant (K = 5. 24 x 10(4)) were obtained. The molecular binding model of the interaction between AA and CS was established. The influence of the molar ratio of AA/CS, ethanol, hydroxypropyl-beta-cyclodextrin, triton X-100 and NaCl on the spectra of AA-CS complex was investigated. We conclude that the color change of complex depends on not only the electrostatic interaction between AA and CS but also the density of AA binding on CS. And the formation of the absorption peak at 550 nm and the color change of complex result mainly from the hydrophobic interaction between AA and AA binding on CS.

A simple, accurate and rapid spectrophotmeric method was proposed for the determination of chondroitin sulfate. The method was based on the absorbances of AA-CS complex at 625 nm being in proportion to the chondroitin sulfate concentrations. The linear range was 0-30 micrograms.mL-1 (R = 0.999), and the recovery range was 97.4%-103.8%. The quantities of chondroitin sulfate in different sample were determined in this way.