Analysis of unsaturated alginate oligosaccharides using high-performance anion exchange chromatography coupled with mass spectrometry.

Alginate is a commercially important polysaccharide composed of mannuronic acid and its C5 differential isomer guluronic acid. Comprehensive research on alginate and alginate lyases requires efficient and precise analytical methods for alginate oligosaccharides. In this research, high-performance anion exchange chromatography (HPAEC) in parallel with pulsed amperometric detection (PAD) and mass spectrometry (MS) was applied to the analysis of oligosaccharides obtained by alginate lyase. By optimizing the chromatographic conditions including mobile phase concentration, flow rate, and elution gradient, the analysis of a single sample could be completed in 30 min. Seven unsaturated alginate oligosaccharides were separated and identified through their analysis time observed with PAD, including all structurally different unsaturated disaccharides and trisaccharides. The quantitative analysis of seven oligosaccharides was performed based on the quantitative capability of PAD. The method exhibited adequate linearity and precision parameters. All the calibration curves showed good linearity at least in the concentration range of 0.002 to 0.1 mg/mL. The HPAEC-PAD/MS method provides a general and efficient online method to analyze alginate oligosaccharides.

Chloroform-infiltrated photonic crystal fiber with high-temperature sensitivity.

The temperature sensor is the core part of the temperature measurement instrument, and its performance directly determines the temperature measurement accuracy. Photonic crystal fiber (PCF) is a new type of temperature sensor with extremely high potential. In this paper, we propose a high-performance, structurally simple, liquid-filled PCF temperature sensor, which is based on a SMF-PCF-SMF (single mode fiber, SMF) sandwich structure. By adjusting the structural parameters of the the PCF, it is possible to obtain optical properties that are superior to those of ordinary optical fibers. This allows for more obvious responsive changes of the fiber transmission mode under small external temperature changes. By optimizing the basic structure parameters, a new PCF structure with a central air hole is designed, and its temperature sensitivity is -0.04696 nm/°C. When filling the air holes of PCFs with temperature-sensitive liquid materials, the response of the optical field against the temperature fluctuations can be effectively enhanced. The Chloroform solution is used to selectively infiltrate the resulting PCF owing to its large thermo-optical coefficient. After comparing various filling schemes, the calculation results show that the highest temperature sensitivity of -15.8 nm/°C is finally realized. The designed PCF sensor has a simple structure, high-temperature sensitivity, and good linearity showing great application potential.

Rapid calculation method for backscattered light of a space gravitational-wave detection telescope.

Stray light is a key issue that must be considered in the TianQin telescope. To solve the problem of a long simulation time and the inability of the simulation results to be fed back to guide the optical design, we propose a fast estimation method for stray light based on the FOV with high accuracy. Compared to other models, the error between our model and the software simulation results is smaller, within one order of magnitude. Based on this method, we obtain the optical component target of the TianQin telescope and propose an optimization method to reduce stray light, which can be verified by analyzing the optimized optical design.

Characterization and elucidation of a novel M-specific alginate lyase Aly7Aq with strict recognition at subsites ±2.

A novel alginate lyase Aly7Aq was cloned and heterologous expressed by a combination of bioinformatics and molecular biology. Aly7Aq was an M-specific alginate lyase, exhibiting optimum reaction conditions at 50 °C and pH 10.0. Aly7Aq was determined to degrade polysaccharides in a random endo-acting manner. The minimum reaction substrate was tetrasaccharide, and Aly7Aq mainly attacked the third glycosidic linkage from the reducing end of oligosaccharide substrates. The disaccharide product of Aly7Aq was ΔM and the trisaccharide products were ΔMM and ΔMG, which differed from all previously characterized M-specific alginate lyases. The degradation products demonstrated that the ±2 subsites of Aly7Aq strictly recognized M units, while the -1 subsite accommodated both M and G units. Therefore, the substrate specificity of Aly7Aq was derived from the specificity of ±2 subsites. This is the first report on the specificity at subsite ±2 of M-specific alginate lyase. The novel M-specific Aly7Aq could serve as a potential tool in the specific degradation of alginate and targeted preparation of oligosaccharide.

Mechanism of folium polygoni cuspidati in liver-yang-hyperactivity hypertension based on network pharmacology, molecular docking and experimental pharmacological validation.

ETHNOPHARMACOLOGICAL RELEVANCE: At present,the global form of hypertension is severe,and liver-yang-hyperactivity hypertension（GYSK hypertension）is the most common type of hypertension.Folium Polygoni Cuspidati（HZY）are mainly used in Yunnan, China,to treat dizziness, headache,and hypertension caused by GYSK,and the content of the active ingredients of HZY and its efficacy varies in different periods.However,the mechanism of action and the effect of harvesting period are not clear. AIM OF THE STUDY: The purpose of this research was to investigate the effect of HZY in April and September on GYSK hypertension. MATERIALS AND METHODS: The model of GYSK hypertension was established with aconite decoction and L-NAME,and the blood pressure,the symptoms of GYSK,the cardiac index and the pathological changes of aorta were observed,to study the effect of HZY in April and September on GYSK hypertension.The chemical composition of HZY was analysed by UPLC-QTOF-MS and its mechanism for the treatment of GYSK hypertension was predicted by network pharmacological studies and experimentally validated using serum metabolomics and Western blot techniques. RESULTS: April HZY and September HZY can significantly improve the GYSK symptoms of rats, inhibit the RAAS system, improve oxidative stress and regulate blood lipids so as to play a blood pressure lowering efficacy and have a protective effect on the vascular endothelial cells.UPLC-QTOF-MS yielded 29 components of HZY,and network pharmacology predicted that its mechanism may be related to Lipid and atherosclerosis,PI3K/Akt signaling pathway, MAPK signaling pathway and TNF signaling pathway,etc.Western Blot validation showed that HZY activated PI3K,p-Akt protein expression and inhibited p-erk,p-p38 and TNF-α protein expression.Serum metabolomics suggested that April HZY exerts its efficacy mainly by regulating amino acid metabolism and September HZY mainly by regulating lipid metabolism. CONCLUSIONS: In GYSK hypertensive rats treated for three weeks, both April HZY and September HZY could have antihypertensive effects,but the mechanisms of action were different and similar, both could regulate metabolite disorders of sugars, lipids,amino acids and peptides,and regulate blood pressure through the PI3K/Akt-eNOS and MAPK signalling pathways, with the difference that April HZY had stronger regulatory effects on the metabolism of amino acids.metabolism.

Discovery and characterization of a novel poly-mannuronate preferred alginate lyase: The first member of a new polysaccharide lyase family.

Alginate is one of the most important marine colloidal polysaccharides, and its oligosaccharides have been proven to possess diverse biological functions. Alginate lyases could specifically degrade alginate and therefore serve as desirable tools for the research and development of alginate. In this report, a novel catalytic domain, which demonstrated no significant sequence similarity with all previously defined functional domains, was verified to exhibit a random endo-acting lyase activity to alginate. The action pattern analysis revealed that the heterologously expressed protein, named Aly44A, preferred to degrade polyM. Its minimum substrates and the minimum products were identified as unsaturated alginate trisaccharides and disaccharides, respectively. Based on the sequence novelty of Aly44A and its homologs, a new polysaccharide lyase family (PL44) was proposed. The discovery of the novel enzyme and polysaccharide lyase family provided a new entrance for the gene-mining and acquiring of alginate lyases, and would facilitate to the utilization of alginate and its oligosaccharides.