Effects of almond (Armeniaca Sibirica L. Lam) polysaccharides on gut microbiota and anti-inflammatory effects on LPS-induced RAW264.7 cells.

The aim of this study was to investigate the prebiotic properties of the almond polysaccharide AP-1 on intestinal microorganisms by using an in vitro fecal fermentation method and its anti-inflammatory effect on lipopolysaccharide (LPS)-induced RAW264.7 cells. The results showed that during the in vitro fermentation of AP-1, the pH value of the fermentation broth decreased obviously, while the concentration of short-chain fatty acids (SCFAs) increased significantly, especially acetic acid and butyric acid. In genus level, the number of Clostridium and Megamonas increased markedly in the AP-1 group after 24 h of fermentation. After 48 h of fermentation, there was a noticeable increase in the number of beneficial genera Lactobacillaceae and Bifidobacteriaceae, and a considerable decrease in the number of pro-inflammatory genera. In addition, we found that AP-1 had no toxic effect on RAW264.7 cells. In the LPS-induced inflammation model of RAW264.7 cells, AP-1 could effectively inhibit the release of NO, regulate the level of reactive oxides (ROS), and effectively down-regulate the mRNA expression of TNF-α, IL-1ß, IL-6 and iNOS. In conclusion, the almond polysaccharide AP-1 may be a functional active substance aimed at promoting intestinal health and exerting anti-inflammatory effects.

Effects of protein aggregation induced by NaCl and temperature on gelation of silkworm (Antheraea pernyi) pupa raw powder.

Edible insects have great potential for producing protein-rich ingredients. This study aimed to investigate the effects of protein aggregation induced by NaCl (0-1 M) and temperature (65-95 °C) on gelation of Antheraea pernyi (A. pernyi) pupa raw powder. No thermal aggregates were observed at low temperature (65 °C), on the basis of there being no significant enhancement in turbidity and particle size (P > 0.05), regardless of NaCl concentrations. At elevated temperatures (75-95 °C), protein solutions exhibited significantly higher turbidity and particle size (P < 0.05), accompanied by an initial rise in surface hydrophobicity followed by a decline, alongside declining sulfhydryl. This marks the beginning of massive thermal aggregation driven by molecular forces. In addition, covalent (disulfide bonds) and non-covalent (hydrogen bonding, electrostatic interactions, and hydrophobicity) forces were influenced by NaCl, leading to variability in the protein aggregation and gelation. Correlation analysis indicates that the higher protein aggregation induced by ions was beneficial to the construction of more compact three-dimensional structures, as well as to the rheology, texture, and water-holding capacity of A. pernyi pupa gels. However, excessive salt ions destroyed the gel structure. Our findings will aid the use of A. pernyi pupae as textural ingredients in formula foods.

Structural characterization, α-glucosidase inhibitory activity and antioxidant activity of neutral polysaccharide from apricot (Armeniaca Sibirica L. Lam) kernels.

Screening for α-glucosidase inhibitors and antioxidants from natural sources that could reduce postprandial glucose in diabetic patients and reduce oxidative stress had attracted considerable interest. In this study, a neutral polysaccharide (AP-1) with a triple helix structure was isolated and purified from the residue of apricot (Armeniaca sibirica L. Lam.) kernels by using DEAE-52 and Sephadex G-100 columns. The molecular weight of AP-1 was 23.408 kDa and consisted mainly of glucose with trace amounts of arabinose, galactose, and mannose, which had molar percentages of 98.48, 0.63, 0.62 and 0.27 %, respectively. The main chain of AP-1 was composed of →4)-α-D-Glcp-(1 â†’ interlinked, and α-D-Glcp-(1 â†’ was attached as a branched chain at the O-6 position of →4,6)-α-D-Glcp-(1→. In addition, AP-1 exhibited stronger α-glucosidase inhibition and free radical scavenging ability compared to crude polysaccharides. Therefore, AP-1 could be used as a potential natural hypoglycemic agent and antioxidant in the treatment of diabetes mellitus.

Real-Time Closed-Loop Detection Method of vSLAM Based on a Dynamic Siamese Network.

As visual simultaneous localization and mapping (vSLAM) is easy disturbed by the changes of camera viewpoint and scene appearance when building a globally consistent map, the robustness and real-time performance of key frame image selections cannot meet the requirements. To solve this problem, a real-time closed-loop detection method based on a dynamic Siamese networks is proposed in this paper. First, a dynamic Siamese network-based fast conversion learning model is constructed to handle the impact of external changes on key frame judgments, and an elementwise convergence strategy is adopted to ensure the accurate positioning of key frames in the closed-loop judgment process. Second, a joint training strategy is designed to ensure the model parameters can be learned offline in parallel from tagged video sequences, which can effectively improve the speed of closed-loop detection. Finally, the proposed method is applied experimentally to three typical closed-loop detection scenario datasets and the experimental results demonstrate the effectiveness and robustness of the proposed method under the interference of complex scenes.

Determination of allosteric and active sites responsible for catalytic activity of delta 12 fatty acid desaturase from Geotrichum candidum and Mortierella alpina by domain swapping.

Cheese lacks essential fatty acids (EFAs). Delta 12 fatty acid desaturase (FADS12) is a critical enzyme required for EFA biosynthesis in fermentation of the predominant strains of cheese. Previously, we identified the FADS12 gene and characterized its function for the first time in Geotrichum candidum, a dominant strain used to manufacture soft cheese with white rind. In this study, we analyzed the molecular mechanism of FADS12 function by swapping domains from Mortierella alpina and G. candidum that had, respectively, high and low oleic acid conversion rates. The results revealed three regions that are essential to this process, including regions from the end of the second transmembrane domain to the beginning of the third transmembrane domain, from the end of the third transmembrane domain to the beginning of the fourth transmembrane domain, and from the 30-amino acid from the end of the sixth transmembrane domain to the C-terminal end region. Based on our domain swapping analyses, nine pairs of amino acids including H112, S118, H156, Q161, K301, R306, E307, A309 and S323 in MaFADS12 (K123, A129, N167, M172, T302, D307, I308, E310 and D324 in GcFADS12) were identified as having a significantly effect on FADS12 catalytic efficiency, and linoleic acid and its analogues (12,13-cyclopropenoid fatty acid) were found to inhibit the catalytic activity of FADS12 and related recombinant enzymes. Furthermore, the molecular mechanism of FADS12 inhibition was analyzed. The results revealed two allosteric domains, including one domain from the N-terminal region to the beginning of the first transmembrane domain and another from the 31st amino acid from the end of the sixth transmembrane domain to the C terminus. Y4 and F398 amino acid residues from MaFADS12 and eight pairs of amino acids including G56, L60, L344, G10, Q13, S24, K326 and L344 in MaFADS12 (while Y66, F70, F345, F20, Y23, Y34, F327 and F345 in GcFADS12) played a pivotal role in FADS12 inhibition. Finally, we found that both allosteric and active sites were responsible for the catalytic activity of FADS12 at various temperatures, pH, and times. This study offers a solid theoretical basis to develop preconditioning methods to increase the rate at which GcFADS12 converts oleic and linoleic acids to produce higher levels of EFAs in cheese.

Comparative exploration of free fatty acids in donkey colostrum and mature milk based on a metabolomics approach.

Donkey milk is an ideal substitute for human milk owing to its similar composition. Nevertheless, changes in the composition and related metabolic pathways of free fatty acids (FFA) in donkey milk between colostrum and mature milk have not been studied well. In this study, metabolomic methods based on gas chromatography tandem time-of-flight mass spectrometry (GC-TOF-MS) were used to explore and compare FFA in donkey colostrum (DC) and mature milk (DMM). A total of 24 FFA were characterized and quantified in DC and in DMM. Of these, 11 FFA differed significantly between DC and DMM, and there were 6 key differential metabolic pathways. These results demonstrated that the composition of FFA in donkey milk changed with lactation stage. The interactions and metabolic pathways were further analyzed to explore the mechanisms that altered the milk composition during lactation. Our results provide insights into the changes in milk of the nonruminant mammals during lactation. The results provide practical information for the development of donkey milk products and a foundation for future research on specific milk nutrients.

Interaction of xylitol with whey proteins: Multi-spectroscopic techniques and docking studies.

This study aimed to examine the interaction mechanism between xylitol (XY) and whey protein isolate (WPI) using multispectral techniques and molecular docking. Additionally, we investigated the effect of XY on WPI functionality using the method of fluorescent probe, high-speed dispersion and differential scanning calorimetry. The fluorescence quenching results such as quenching constants, binding constants and thermodynamic parameters showed strong susceptibility to interacting of WPI and its fractions to XY and the sequence was: α-lactalbumin (α-La) > bovine serum albumin (BSA) > ß-lactoglobulin (ß-Lg). Docking results revealed that XY was bound to the residues of aromatic cluster II in α-La, the hydrophobic cavity of ß-Lg and the subdomain IIA of BSA through hydrogen bonding and van der Waals forces, resulting in conformational changes in secondary structures of proteins, which converted α-helix to ß-turn and random coils. Further, XY increased thermal stability and emulsifying properties and reduced surface hydrophobicity and zeta-potential of WPI.

Δ12 fatty acid desaturase gene from Geotrichum candidum in cheese: molecular cloning and functional characterization.

Soft cheese with white rind lacks essential fatty acids (EFAs), and as a result its long-term consumption may lead to various kinds of cardiovascular and cerebrovascular diseases, such as hyperlipidemia, hypertension, and atherosclerosis. Geotrichum candidum is a dimorphic yeast that plays an important role in the ripening of mold cheese. A gene coding for Δ12 fatty acid desaturase, a critical bifunctional enzyme desaturating oleic acid (OA) and linoleic acid (LA) to produce LA and α-linolenic acid (ALA), respectively, was isolated from G. candidum, and then cloned and heterologously expressed in Saccharomyces cerevisiae. This gene, named GcFADS12, had an open reading frame of 1257 bp and codes for a protein of 419 amino acids with a predicted molecular mass of 47.5 kDa. Characterization showed that GcFADS12 had the ability to convert OA to LA and LA to ALA, and the conversion rates for OA and LA were 20.40 ± 0.66% and 6.40 ± 0.57%, respectively. We also found that the protein product of GcFADS12 catalyzes the conversion of the intermediate product (LA) to ALA by addition of OA as the sole substrate. The catalytic activity of GcFADS12 on OA and LA was unaffected by fatty acid concentrations. Kinetic analysis revealed that GcFADS12 had stronger affinity for the OA than for the LA substrate. This study offers a solid basis for improving the production of EFAs by G. candidum in cheese.

In vitro inhibitory activities of six gypenosides on human liver cancer cell line HepG2 and possible role of HIF-1α pathway in them.

During our phytochemical investigation of Gynostemma pentaphyllum (Thunb.) Makino, six gypenosides (compounds 1-6) were isolated and determined, including two with a 21,23-epoxy group (1, 2), two with a 21,23-lacton skeleton (3, 4), and two with usual side-chain (5, 6). In this research, we studied their possible in vitro inhibitory activities on cancer cell line HepG2 under hypoxic conditions, explored the role of HIF-1α pathway in them and discussed the potential antitumor gradients and conduct analysis of structure-activity relationships (SAR). They and gensenoside-Rg3 were tested for different assays. Compounds 1-4 showed moderate antitumor activities against HepG2 by MTT assay, inhibited HIF-1α mRNA expression, as well as disturbing HepG2 migration and invasion, superior to Rg3. Correlations were found for gypenosides with different side chain on inhibiting HepG2 proliferation activity, the ones have epoxy structure showed the highest effect. These results supported the potential application of G. pentaphyllum as a functional food for hepatoprotection.

Wound healing by a 3.2 kDa recombinant polypeptide from velvet antler of Cervus nippon Temminck.

Velvet antler (VA) is used in traditional Chinese medicine to treat a wide range of ailments including the enhancement of wound healing. A 3.2 kDa recombinant polypeptide of VA from sika deer was purified and compared to native polypeptides stimulation growth of NIH3T3 cells. Both stimulated growth in a dose-dependent manner (10-100 µg/ml). To study its wound healing properties, burn-wounded rats were topically administered with recombinant VA polypeptide or native polypeptide. Rats treated with 0.05 and 0.1% (w/w) polypeptides exhibited significant wound healing. As the yield of recombinant polypeptide was 40-fold higher than that of the native polypeptide, it may therefore be a useful biopharmaceutical.