Conformation-Activity Mechanism of Alcalase Hydrolysis for Reducing In Vitro Allergenicity of Instant Soy Milk Powder.

Effective reduction of the allergenicity of instant soy milk powder (ISMP) is practically valuable for expanding its applications. This study optimized the enzymolysis technology of ISMP using single-factor experiments and response surface methodology, combined serological analysis, cellular immunological models, bioinformatics tools, and multiple spectroscopy techniques to investigate the effects of alcalase hydrolysis on allergenicity, spatial conformation, and linear epitopes of ISMP. Under the optimal process, special IgE and IgG1 binding abilities and allergenic activity to induce cell degranulation of alcalase-hydrolyzed ISMP were reduced by (64.72 ± 1.76)%, (56.79 ± 3.72)%, and (73.3 ± 1.19)%, respectively (P < 0.05). Moreover, the spatial conformation of instant soy milk powder hydrolysates (ISMPH) changed, including decreased surface hydrophobicity, a weaker peak of amide II band, lower contents of α-helix and ß-sheet, and an enhanced content of random coil. Furthermore, the linear epitopes of major soy allergens, 9 from glycinin and 13 from ß-conglycinin, could be directionally disrupted by alcalase hydrolysis. Overall, the structure-activity mechanism of alcalase hydrolysis to reduce ISMP allergenicity in vitro was preliminarily clarified. It provided a new research direction for the breakthrough in the desensitization of ISMP and a theoretical basis for revealing the potential mechanism of alcalase enzymolysis to reduce the allergenicity of ISMP.

Chromate-induced methylglyoxal detoxification system drives cadmium and chromate immobilization by Cupriavidus sp. MP-37.

The detoxification of cadmium (Cd) or chromium (Cr) by microorganisms plays a vital role in bacterial survival and restoration of the polluted environment, but how microorganisms detoxify Cd and Cr simultaneously is largely unknown. Here, we isolated a bacterium, Cupriavidus sp. MP-37, which immobilized Cd(II) and reduced Cr(VI) simultaneously. Notably, strain MP-37 exhibited variable Cd(II) immobilization phenotypes, namely, cell adsorption and extracellular immobilization in the co-presence of Cd(II) and Cr(VI), while cell adsorption in the presence of Cd(II) alone. To unravel Cr(VI)-induced extracellular Cd(II) immobilization, proteomic analysis was performed, and methylglyoxal-scavenging protein (glyoxalase I, GlyI) and a regulator (YafY) showed the highest upregulation in the co-presence of Cd(II) and Cr(VI). GlyI overexpression reduced the intracellular methylglyoxal content and increased the immobilized Cd(II) content in extracellular secreta. The addition of lactate produced by GlyI protein with methylglyoxal as substrate increased the Cd(II) content in extracellular secreta. Reporter gene assay, electrophoretic mobility shift assay, and fluorescence quenching assay demonstrated that glyI expression was induced by Cr(VI) but not by Cd(II), and that YafY positively regulated glyI expression by binding Cr(VI). In the pot experiment, inoculation with the MP-37 strain reduced the Cd content of Oryza sativa L., and their secreted lactate reduced the Cr accumulation in Oryza sativa L. This study reveals that Cr(VI)-induced detoxification system drives methylglyoxal scavenging and Cd(II) extracellular detoxification in Cd(II) and Cr(VI) co-existence environment.

Characterization of a synergistic antioxidant synthetic peptide from sea cucumber and pine nut.

We compared antioxidant activity of the synthetic peptide Val-Leu-Leu-Tyr-Gln-Asp-His-Cys-His (VLLYQDHCH), sea cucumber peptide Val-Leu-Leu-Tyr (VLLY) and pine seed peptide Gln-Asp-His-Cys-His (QDHCH). The structure-activity relationship was analyzed based on radical scavenging ability and Raman, circular dichroism (CD) and nuclear magnetic resonance spectroscopy (NMR). Based on RP-HPLC, the contents of peptides in simulated gastrointestinal tract and digestive juices in rat intestinal sac were determined, and their absorption stability were explored. These results showed that the DPPH clearance rate of VLLYQDHCH was 45.90% higher than the sum of VLLY and QDHCH at 3 mmol/L. The α-helix, ß-sheet and random coil of VLLYQDHCH increased, ß-turn decreased, and the active hydrogen site shifted. After simulated digestion and absorption, the retention rate of VLLYQDHCH was 80.86 ± 0.88% in simulated stomach and 45.75 ± 0.97% in simulated intestine. There was no significant difference in the absorption rates of the three peptides (P > 0.05). This research provided a new idea for the development of safe and green food-derived animal-plant protein antioxidant peptides.

Evaluation of the structure-activity relationship between allergenicity and spatial conformation of ovalbumin treated by pulsed electric field.

The aim of the present study was to investigate the effect of pulsed electric field (PEF) treatment on ovalbumin (OVA) induced allergens and reveal potential allergy regulatory mechanisms. At 10 kV/cm, OVA-induced allergic symptoms were significantly reduced, and the capacity of OVA to bind with specific IgG1 and IgE was reduced by 10.32% and 3.61%, respectively. Furthermore, the degranulation of RBL-2H3 cells and allergen activity were also reduced by 4.63% and 22.15%, respectively. Interestingly, the α-helix content was reduced by 5.81% and the fluorescence intensity was increased by 6.90% with PEF treatment. At 10 kV/cm, water contact angle and surface hydrophobicity increased by 8.40% and 0.18%, respectively, indicating that PEF treatment increased the exposure of hydrophobic amino acid residues. PEF treatment alters the hydrogen bonding and hydrophobic interactions in the protein, which masks the binding sites of sensitized epitopes, and consequently reduces allergies.

Cd immobilization mechanisms in a Pseudomonas strain and its application in soil Cd remediation.

In this study, we isolated a highly cadmium (Cd)-resistant bacterium, Pseudomonas sp. B7, which immobilized 100% Cd(II) from medium. Culturing strain B7 with Cd(II) led to the change of functional groups, mediating extracellular Cd(II) adsorption. Proteomics showed that a carbonic anhydrase, CadW, was upregulated with Cd(II). CadW expression in Escherichia coli conferred resistance to Cd(II) and increased intracellular Cd(II) accumulation. Fluorescence assays demonstrated that CadW binds Cd(II) and the His123 residue affected Cd(II) binding activity, indicating that CadW participates in intracellular Cd(II) sequestration. Chinese cabbage pot experiments were performed using strain B7 and silicate [Si(IV)]. Compared with the control, Cd content in aboveground parts significantly decreased by 21.3%, 29.4% and 32.9%, and nonbioavailable Cd in soil significantly increased by 129.4%, 45.0% and 148.7% in B7, Si(IV) and B7 +Si(IV) treatments, respectively. The application of Si(IV) alone reduced chlorophyll content by 20.8% and arylsulfatase activity in soil by 33.9%, and increased malonaldehyde activity by 15.0%. The application of strain B7 alleviated the negative effect of Si(IV) on plant and soil enzymes. Overall, application of Si(IV) is most conducive to the decreased Cd accumulation in plant, and strain B7 is beneficial to maintaining soil and plant health.

Reducing the allergenicity of pea protein based on the enzyme action of alcalase.

Enzymatic hydrolysis could be one of the crucial means to limit the allergenicity of allergens. The allergenicity of pea peptides was evaluated using indirect ELISA and RBL-2H3 cell assay, thereby obtaining hypoallergenic pea peptide sequences. Results indicated that pea protein-sensitized mice produced higher levels of total IgG1 and IgE antibodies than the mice in the control group (P < 0.05). Moreover, the allergenicity of hydrolysates decreased significantly after enzymolysis, and the allergenicity of ultrafiltration component F1 and purified component F1-2 was significantly lower than that of other isolated and purified components (P < 0.05). Furthermore, ADLYNPR identified from F1-2 had lower binding capacity to specific IgE and IgG1 and lower degree of cell degranulation with a higher EC50 value of 6.63 ng mL-1, which was about 36.83 times that of pea protein (P < 0.05). Based on the above results, ADLYNPR might be a potential source of hypoallergenic peptides.

Reduced Adhesive Force Leading to Enhanced Thermal Stability of Soy Protein Particles by Combined Preheating and Ultrasonic Treatment.

Developing liquid systems with high protein contents is drawing intensive attention; however, this is challenged by heat-induced aggregation and gelation of proteins. Herein, we described a facile but robust approach of combined preheating and ultrasonic treatment (CPUT) to fabricate soy protein particles (SPPs) with enhanced heat stability. Results showed that these heat-stable particles, upon reheating at 1% (w/v), showed antiaggregation property evidenced from no obvious changes of the particle size distributions of suspensions. Besides, no gelation was found in the reheated test for SPPs suspended even at a concentration of 10% (w/v). In contrast, the control formed sol-gel after heating. The rearrangements of soy protein molecules by CPUT led to the formation of SPPs with reduced surface energy, which was primarily responsible for their heat stability. These findings highlighted that the CPUT could prepare thermally stable soy proteins, providing insights into the application of soy proteins in protein-enriched beverages.

Quantitative analysis of excipient dominated drug formulations by Raman spectroscopy combined with deep learning.

Owing to the growing interest in the application of Raman spectroscopy for quantitative purposes in solid pharmaceutical preparations, an article on the identification of compositions in excipient dominated drugs based on Raman spectra is presented. We proposed label-free Raman spectroscopy in conjunction with deep learning (DL) and non-negative least squares (NNLS) as a solution to overcome the drug fast screening bottleneck, which is not only a great challenge to drug administration, but also a major scientific challenge linked to falsified and/or substandard medicines. The result showed that Raman spectroscopy remains a cost effective, rapid, and user-friendly method, which if combined with DL and NNLS leads to fast implantation in the identification of lactose dominated drug (LDD) formulations. Meanwhile, Raman spectroscopy with the peak matching method allows a visual interpretation of the spectral signature (presence or absence of active pharmaceutical ingredients (APIs) and low content APIs).

Sediminibacterium soli sp. nov., isolated from soil.

A Gram-stain-negative, facultative anaerobic strain, designated WSJ-3T, was isolated from soil. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain WSJ-3T belongs to genus Sediminibacterium and exhibits the highest sequence similarities to Sediminibacterium roseum SYL130T (97.0%), Sediminibacterium goheungense DSM 28323T (96.9%), Sediminibacterium aquarii AA5T (96.7%), and Sediminibacterium salmoneum NBRC 103935T (95.2%). The average nucleotide identity values of strain WSJ-3T/S. roseum SYL130T and strain WSJ-3T/S. goheungense DSM 28323T are 72.2% and 70.4%, respectively, and digital DNA-DNA hybridization values for these are 19.2% and 19.1%, respectively. Strain WSJ-3T has a genome size of 3.88 Mb, with a DNA G + C content of 50.1 mol% and comprises of 3263 predicted genes. A phylogenetic tree constructed using the genomic core protein coding sequences revealed that strain WSJ-3T clusters with S. roseum SYL130T. Strain WSJ-3T has menaquinone-7 as the only respiratory quinone and phosphatidylethanolamine, three unidentified phospholipids, four unidentified aminophospholipids, two unidentified aminolipids, and three unidentified lipids as the polar lipids. The major fatty acids of strain WSJ-3T are iso-C15:0, iso-C17:0 3-OH, and iso-C15:1 G. On the basis of the polyphasic results, the isolate represents a novel species of the genus Sediminibacterium, for which the name Sediminibacterium soli sp. nov. is proposed. The type strain is WSJ-3T (= KCTC 72839T = CCTCC AB 2019408T).

Echinacoside promotes the proliferation of human renal tubular epithelial cells by blocking the HBX/TREM2­mediated NF­κB signalling pathway.

Hepatitis B virus X (HBX) protein is required for the replication of HBV and plays a role in the progression of hepatitis in humans. However, the underlying function of HBX during HBV­induced chronic glomerulonephritis (HBV­GN) is unknown. Echinacoside (ECH) is a phenylethanoid glycoside from the Cistanche genus, which possesses strong antiapoptosis and neuroprotective activities. In the present study, the function of HBX and the relationship between HBX and ECH in human renal tubular epithelial cells (RTECs; HK­2 cell line) were explored. Reverse transcription­quantitative PCR and western blot analyses were used to quantify the mRNA and protein expression levels of HBX in HK­2 cells, respectively. The Cell Counting Kit­8 assay was performed to analyse cell proliferation. Flow cytometry analysis was used to determine the rate of apoptosis. HBX showed antiproliferative and proapoptotic effects in HK­2 cells and was positively associated with triggering receptor expressed on myeloid cells 2 (TREM2) expression. Furthermore, ECH disrupted the function of HBX in HK­2 cells, functioning as an HBX suppressor. Moreover, a specific NF­κB inhibitor, PDTC, was used to further examine the relationship between HBX and NF­κB. The results suggested that NF­κB was involved in the HBX/TREM2 signaling pathway and negatively regulated TREM2 expression in RTECs. The present study provided novel insights into the function of HBX, and also indicated the potential value of ECH as a therapeutic agent for HBV­GN.