Anticoagulant and antithrombotic activities of low-molecular-weight propylene glycol alginate sodium sulfate (PSS)

X-ray photoelectron spectroscopy (XPS) is a powerful tool to study surface properties (< 10 nm) and is being widely used in almost all branches of science and engineering. This review provides a pedagogical description of the fundamental understanding of XPS based surface characterization with the necessary background and key concepts, details on primary factors influencing surface analysis, issues in XPS analysis and identification of chemical bonding/oxidation state of elements. The basic theory of XPS and the most frequently used “core level peaks” analysis in the conventional use of XPS are presented, along with the details of valence band analysis. The challenges encountered during surface analysis, especially for phase composition identification, are briefly discussed. Further, a few selected recent applications of the XPS technique in various scientific fields are also highlighted. The recent development in the area of surface phase identification by valence band analysis using XPS, along with its advantages and challenges in the determination of nanoscale thin film phase composition are also detailed. This review also provides an overview of the significance of XPS as a tool for surface characterization in the field of material science, nanoscience, mining and mineral extraction, metallurgy, semiconductors, coatings, inorganic materials, tribology, organic materials, corrosion science and electrochemistry. The review should be an ideal material for researchers and also serves as an excellent reference for freshers who plan to begin research on this topic. 

Review on surface-characterization applications of X-ray photoelectron spectroscopy (XPS): Recent developments and challenges

Polymannuronic acid prevents dopaminergic neuronal loss via brain-gut-microbiota axis in Parkinson's disease model

The heparin-like activities of negatively charged derivatives of low-molecular-weight polymannuronate and polyguluronate

Carrageenan oligosaccharides have drawn considerable attention for their potential application in various technologies. The objective of this study was to develop a high-efficiency method to prepare carrageenan oligosaccharides directly from Eucheuma cottonii using cellulase and recombinant κ-carrageenase. The recombinant κ-carrageenase was produced by Escherichia coli BL21-HTa- cgk Z, which expresses κ-carrageenase from a marine bacterium. Dried seaweed was first digested with cellulase at pH 5.0 and 50 °C for 2 h, and then with recombinant κ-carrageenase. To improve oligosaccharide recovery, the parameters of carrageenase hydrolysis were optimized using central composite design and validated. Using this method, E. cottonii oligosaccharides (ECO) were recovered with a 38% yield. High-performance gel permeation chromatography (HPGPC), Fourier transform infrared spectrometry (FT-IR), and electrospray ionization-mass spectrometry (ESI-MS) results indicated that ECO possess characteristics specific to carrageenan oligosaccharides, in particular hexasaccharides.

An effective method for the preparation of carrageenan oligosaccharides directly from Eucheuma cottonii using cellulase and recombinant κ-carrageenase

Preparation, characterization and antioxidant activities of polymannuronic acid phosphate, H-phosphonate and sulfate

Chlorite, as the most representative gangue mineral associated with specularite, of which the separation of these two minerals is difficult. This paper investigated the depression effect of taurine on specularite/chlorite separation via flotation experiments, adsorption tests, contact angle measurements, Zeta potential detection, FT-IR measurements, and XPS analyses. The results of single mineral flotation indicated that chlorite could be depressed selectively by taurine with the recovery of less than 30%, but the floatability of specularite remains high with recovery rate of 81.77% at pH 10. The artificial mixed mineral flotation results confirmed the effectiveness of taurine as a depressant. Surface adsorption, contact angle, and Zeta potential detection revealed taurine primarily adsorbs on the chlorite surface, which hampered the DDA’s subsequent adsorption and results in the chlorite’s poor floatability. The FT-IR spectra and XPS analyses provided further proof that taurine adsorbed on chlorite surface as an electron donor, and part of the electrons transferred from the sulfonic acid group of taurine to metal ions during the adsorption process. In addition, the hydrogen bond between amino-group of taurine and O ions in chlorite surface was also formed in the adsorption process. Finally, optimized adsorption configurations of taurine on chlorite surfaces were proposed. 

Selective depression action of taurine in flotation separation of specularite and chlorite

Protein tyrosine phosphatase 1B (PTP1B) is a critical negative modulator of insulin signaling and has attracted considerable attention in treating type 2 diabetes mellitus (T2DM). Low-molecular-weight polymannuronic acid phosphate (LPMP) was found to be a selective PTP1B inhibitor with an IC50 of 1.02 ± 0.17 μM. Cellular glucose consumption was significantly elevated in insulin-resistant HepG2 cells after LPMP treatment. LPMP could alleviate oxidative stress and endoplasmic reticulum stress, which are associated with the development of insulin resistance. Western blot and polymerase chain reaction (PCR) analysis demonstrated that LPMP could enhance insulin sensitivity through the PTP1B/IRS/Akt transduction pathway. Furthermore, animal study confirmed that LPMP could decrease blood glucose, alleviate insulin resistance, and exert hepatoprotective effects in diabetic mice. Taken together, LPMP can effectively inhibit insulin resistance and has high potential as an anti-diabetic drug candidate to be further developed.

A Novel PTP1B Inhibitor-Phosphate of Polymannuronic Acid Ameliorates Insulin Resistance by Regulating IRS-1/Akt Signaling

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9721379

Inhibitory activities of alginate phosphate and sulfate derivatives against SARS-CoV-2 in vitro

Age-related macular degeneration (AMD) is the leading cause of vision loss among the elderly. The progression of AMD is closely related to oxidative stress in the retinal pigment epithelium (RPE). Here, a series of chitosan oligosaccharides (COSs) and N-acetylated derivatives (NACOSs) were prepared, and their protective effects on an acrolein-induced oxidative stress model of ARPE-19 were explored using the MTT assay. The results showed that COSs and NACOs alleviated APRE-19 cell damage induced by acrolein in a concentration-dependent manner. Among these, chitopentaose (COS–5) and its N-acetylated derivative (N–5) showed the best protective activity. Pretreatment with COS–5 or N–5 could reduce intracellular and mitochondrial reactive oxygen species (ROS) production induced by acrolein, increase mitochondrial membrane potential, GSH level, and the enzymatic activity of SOD and GSH-Px. Further study indicated that N–5 increased the level of nuclear Nrf2 and the expression of downstream antioxidant enzymes. This study revealed that COSs and NACOSs reduced the degeneration and apoptosis of retinal pigment epithelial cells by enhancing antioxidant capacity, suggesting that they have the potential to be developed into novel protective agents for AMD treatment and prevention.

/pdf/chitooligosaccharides-derivatives-protect-arpe-19-cells-qhvufe4s.pdf

Cheng Yang

Papers

Preparation, characterization and antioxidant activities of polymannuronic acid phosphate, H-phosphonate and sulfate

Selective depression action of taurine in flotation separation of specularite and chlorite

A Novel PTP1B Inhibitor-Phosphate of Polymannuronic Acid Ameliorates Insulin Resistance by Regulating IRS-1/Akt Signaling

Inhibitory activities of alginate phosphate and sulfate derivatives against SARS-CoV-2 in vitro

Chitooligosaccharides Derivatives Protect ARPE-19 Cells against Acrolein-Induced Oxidative Injury