Modulation of gut microbiota by chondroitin sulfate calcium complex during alleviation of osteoporosis in ovariectomized rats.

Although chondroitin sulfate calcium complex (CSCa) was claimed to have the bioactivity for bone care in vitro, its anti-osteoporosis bioactivity was little reported in vivo. Here, the effects of CSCa on osteoporosis rats were investigated. Results showed that, compared with the osteoporosis rats, CSCa could improve the bone mineral density and microstructure of femur, and change the bone turnover markers level in serum. 16S rRNA sequencing and metabolomics analysis indicated CSCa intervention altered the composition of gut microbiota along with metabolite profiles in ovariectomized rat faeces. The correlation analysis showed some gut microbiota taxa were significantly correlated with osteoporosis phenotypes and the enriched metabolites. Taken together, dietary CSCa intervention has the potential to alleviate the osteoporosis and related symptoms probably involving gut microbiota or the metabolite profiles as demonstrated in rats. This study provides some scientific evidence for the potential effects of CSCa as the food supplement on the osteoporosis.

Fabrication of chondroitin sulfate calcium complex and its chondrocyte proliferation in vitro.

Chondroitin sulfate (CS)-calcium complex (CSCa) was fabricated, and the structural characteristics of CSCa and its proliferative bioactivity to the chondrocyte were investigated in vitro. Results suggested calcium ions could bind CS chains forming polysaccharide-metal complex, and the maximum calcium holding capacity of CSCa reached 4.23 %. Characterization of CSCa was performed by EDS, AFM, FTIR, UV, XRD and 1H-NMR. It was found that calcium ions were integrated with CS by binding the sulfate or carboxyl groups. The thermal properties analysis indicated CSCa had a good thermal stability by TGA and DSC. CSCa could interact the calcium-sensing receptor increasing the intracellular calcium ions and influence the cell cycle. The TGF-ß1 secretion induced by CSCa could activate the TGF-ß/Smads pathway and change the genes associated proliferation expression ultimately leading to the chondrocyte proliferation. This research probably has an important implication for understanding the effect of CSCa on bone care as food supplements.

[HNMP]HSO4 catalyzed synthesis of selenized polysaccharide and its immunomodulatory effect on RAW264.7 cells via MAPKs pathway.

In this paper, selenized Artemisia sphaerocephala polysaccharides (SePAS) were obtained through employing N-methyl-2-pyrrolidone hydrosulfate as catalyst, which showed a maximum Se content enhanced to 8744 µg/g. FT-IR, 1D/2D NMR, X-ray photoelectron spectroscopy (XPS) and size-exclusion chromatograph analysis exhibited that Se had been successfully introduced into PAS and existed in the form of selenate group (Se4+) with the substitution position at C-6. Furthermore, immunostimulating assays indicated that SePAS with high Se content exhibited stronger immunomodulatory activities by upregulated the phosphorylation level of ERK, JNK and p38, thus enhancing RAW264.7 cells proliferation, phagocytosis, levels of interleukin-6, nitric oxide, tumor necrosis factor and interleukin-1ß. The current outcome suggested that Se content might be a critical factor affecting the immunomodulatory effects of selenized PAS on macrophage RAW264.7.

A comparative study of sulfated tara gum: RSM optimization and structural characterization.

Interest in galactomannans and its derivatives as a functional health supplement is growing based on physicochemical properties. In this work, the optimized conditions of sulfated tara gum (STG) with a maximum DS of 0.66 by box-behnken design (BBD) were obtained as following: ratio of chlorosulfonic acid/pyridine 3:1, reaction time 4 h and reaction temperature 40 °C. The structure features of STG such as the degree of substitution (DS), substitution position, weight average molar mass (MW), monosaccharide components and chain conformation were investigated. Decreasing of MW, the increasing of Z-average radius of gyration (〈S2〉Z1/2) and specific volume for gyration (SVg) were obtained by SEC-MALLS. In addition, the structural properties of four sulfated galactomannans were comparatively investigated and analyzed based on our earlier reports of sulfated fenugreek gum, guar gum and locust bean gum. A conclusion was drown that higher galactose branch could enhance steric hindrance, which was inferred as one of the significant factors for the derivatization efficiency, thus affecting the DS, MW and conformational transition of sulfated galactomannans. This study will provide valuable information for further research on the comparison of bioactivities and medical application of galactomannans family.

Metabolomics strategy reveals the osteogenic mechanism of yak (Bos grunniens) bone collagen peptides on ovariectomy-induced osteoporosis in rats.

Our previous work demonstrated that yak bone collagen peptides (YBP) possessed excellent osteogenic activity in vitro. However, associations between YBP and osteoporosis were less established, and the positive effect and underlying mechanism of YBP in the treatment of osteoporotic rats in vivo remained unclear. Herein, ovariectomized rats were intragastrically administered with YBP or 17ß-estradiol for 12 weeks. Bone turnover markers, bone biomechanical parameters and bone microarchitecture were investigated to identify the specific changes of potential antagonistic effects of YBP on ovariectomized rats. Then, serum samples were analyzed by UPLC/Q-TOF-MS to identify metabolites. The results showed that YBP treatment remarkably altered the content of serum bone turnover markers and prevented the ovariectomy-induced deterioration of bone mechanical and microarchitecture characteristics. A total of forty-one biomarkers for which levels changed markedly upon treatment have been identified based on non-targeted metabolomics. Among them, twenty-one metabolites displayed a downward expression level, while twenty metabolites showed an upward expression level in the YBP group and finally were selected as potential biomarkers. The levels of these biomarkers displayed significant alterations and a tendency to be restored to normal values in YBP treated osteoporotic rats. A systematic network analysis of their corresponding pathways delineated that the protective or recovery effect of YBP on osteoporosis occurred primarily by regulating the amino acid metabolism and lipid metabolism (especially unsaturated fatty acid). Collectively, these findings highlight that such peptides hold promise in further advancement as a natural alternative for functional and health-promoting foods, which could be potentially used in mediated treatment of osteoporosis.

Nanoconjugates of Ag/Au/Carbon Nanotube for Alkyne-Meditated Ratiometric SERS Imaging of Hypoxia in Hepatic Ischemia.

We report a ratiometric surface-enhanced Raman scattering (SERS) nanoprobe for imaging hypoxic living cells or tissues, using azo-alkynes assembled on a single-walled carbon nanotube (SWCNT) surface-functionalized with Ag/Au alloy nanoparticles (SWCNT/Ag/AuNPs). Under a hypoxic condition, azobenzene derivatives preassembled on the surface of the nanostructures are reduced stepwise by various reductases and eventually removed from the surface of the SWCNT/Ag/AuNPs, resulting in the loss of characteristic alkyne Raman bands at 2207 cm-1. Using 2D-band of SWCNTs at 2578 cm-1 as the internal standard, we are able to determine the hypoxia level based on the ratio of two peak intensities ( I2578/ I2207) as demonstrated by the successful detection in different cell lines and rat liver tissue samples derived from hepatic ischemia surgery. By combining the outstanding anti-interference property of alkynes as SERS reporters and the distinct Raman responses of alkynes and SWCNTs in complex systems, this novel ratiometric SERS strategy holds promise in becoming a very useful tool for in vitro and in vivo monitoring of hypoxia in research and clinical settings.

Quantitative proteomics reveals the crucial role of YbgC for Salmonella enterica serovar Enteritidis survival in egg white.

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a food-borne bacterial pathogen that can cause human salmonellosis predominately by contamination of eggs and egg products. However, its survival mechanisms in egg white are not fully understood, especially from a proteomic point of view. In this study, the proteomic profiles of S. Enteritidis in Luria-Bertani (LB) broth containing 50% and 80% egg white, and in whole egg white were compared with the profile in LB broth using iTRAQ technology to identify key proteins that were involved in S. Enteritidis survival in egg white. It was found that there were 303, 284 and 273 differentially expressed proteins in S. Enteritidis after 6 h exposure to whole, 80% and 50% egg white, respectively. Most of up-regulated proteins were primarily associated with iron acquisition, cofactor and amino acid biosynthesis, transporter, regulation and stress responses, whereas down-regulated proteins were mainly involved in energy metabolism, virulence as well as motility and chemotaxis. Three stress response-related proteins (YbgC, TolQ, TolA) of the tol-pal system responsible for maintaining cell membrane stability of Gram-negative bacteria were up-regulated in S. Enteritidis in response to whole egg white. Interestingly, deletion of ybgC resulted in a decreased resistance of S. Enteritidis to egg white. Compared with the wild type and complementary strains, a 3-log population reduction was observed in △ybgC mutant strain after incubation in whole egg white for 24 h. Cellular morphology of △ybgC mutant strain was altered from rods to spheres along with cell lysis in whole egg white. Furthermore, deletion of ybgC decreased the expression of tol-pal system-related genes (tolR, tolA). Collectively, these proteomic and mutagenic analysis reveal that YbgC is essential for S. Enteritidis survival in egg white.