To adapt to external stimuli, bacteria fine-tune important protein activities using post-translational modifications. The present study provides novel insights into the molecular mechanism of the ...antimicrobial peptide BCp12. We demonstrate that BCp12 significantly suppressed bacterial growth, induced cell apoptosis, and modulated overall malonylation levels in Staphylococcus aureus cells. Malonylateomic analysis was performed to identify the proteins malonylated by the BCp12 treatment of S. aureus. In total, 53 malonylated proteins (17 up-regulated, 36 down-regulated) were identified as differentially expressed malonylated proteins (DMPs; > 1.5-fold or <0.67-fold, P < 0.05). This result was confirmed via the identification of 21 differential metabolites (DMs; VIP > 1, P < 0.05) in the arginine and proline metabolome. Bioinformatic analysis revealed that the DMPs and DMs were especially enriched in the arginine synthesis pathway. By integrating our lysine malonylational and metabolomic data, we provide new insights into the mechanism by which BCp12 inhibits S. aureus.
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•The commonly used electrolyte of aqueous zinc-ion batteries is modified by additives.•The added amounts of diethyl ether and ethylene glycol are optimized systematically.•The ...cyclability and anti-freezing ability of battery can be improved significantly.•Good performances of the battery with modified electrolyte can be obtained at –10 ℃.•The interfacial stability between zinc and electrolyte can be improved significantly.
Due to their low cost, high safety, environmental friendliness, and impressive electrochemical performances, aqueous zinc-ion batteries are considered promising alternative technologies to lithium-ion batteries for use in large-scale applications. However, existing aqueous zinc-ion batteries usually suffer from poor cyclability and cannot operate at subzero temperatures. Herein, to solve these problems, the electrolyte in aqueous zinc-ion batterie is optimized by adding the appropriate amounts of diethyl ether and ethylene glycol. Results show that the addition of 1% diethyl ether contributes to the best cyclability at 25 °C. Furthermore, the addition of 30% ethylene glycol results in the best electrochemical performances at 0 and − 10 °C. This significant performance improvement at low temperatures is ascribed to the high ionic conductivity of the modified electrolyte and the low charge transfer impedance of the battery with the modified electrolyte at 0 and −10 °C. It is also shown that the modified electrolyte can decrease the nucleation overpotential of zinc plating, enhance the interfacial stability between the zinc metal and electrolyte, suppress the zinc dendritic growth and side reactions, and decrease the self-corrosion rate of the zinc anode. This work offers a facile strategy to realize aqueous zinc-ion batteries with excellent cyclability and antifreezing ability and may inspire research on other aqueous energy storage systems.
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•Two proteases (P1831 and P191) were isolated from Prinsepia utilis Royle.•Both proteases showed hydrolase and catabolic activity.•Both proteases were stable under pH 4–6 and at ...30–80 °C.•Proteases hydrolyzed κ-CN more effectively than α-CN and β-CN.•Proteases from P. utilis Royle showed potential application in cheese processing.
The aim of this study was to isolate and identify the main milk-clotting proteases from Prinsepia utilis Royle. Protein isolates obtained using precipitation with 20 %–50 % ammonium sulfate (AS) showed higher milk-clotting activity (MCA) at 154.34 + 0.35 SU. Two milk-clotting proteases, namely P191 and P1831, with molecular weight of 49.665 kDa and 68.737 kDa, respectively, were isolated and identified using liquid chromatography-mass spectrometry (LC-MS/MS). Bioinformatic analysis showed that the two identified milk-clotting proteases were primarily involved in hydrolase activity and catabolic processes. Moreover, secondary structure analysis showed that P191 structurally consisted of 40.85 % of alpha-helices, 15.96 % of beta-strands, and 43.19 % of coiled coil motifs, whereas P1831 consisted of 70 % of alpha-helices, 7.5 % of beta-strands, and 22.5 % of coiled coil motifs. P191 and P1831 were shown to belong to the aspartic protease and metalloproteinase types, and exhibited stability within the pH range of 4–6 and good thermal stability at 30–80 °C. The addition of CaCl2 (<200 mg/L) increased the MCA of P191 and P1831, while the addition of NaCl (>3 mg/mL) inhibited their MCA. Moreover, P191 and P1831 preferably hydrolyzed kappa-casein, followed by alpha-casein, and to a lesser extent beta-casein. Additionally, cheese processed with the simultaneous use of the two proteases isolated in the present study exhibited good sensory properties, higher protein content, and denser microstructure compared with cheese processed using papaya rennet or calf rennet. These findings unveil the characteristics of two proteases isolated from P. utilis, their milk-clotting properties, and potential application in the cheese-making industry.
In this study, Pickering emulsion (PE) stabilized by whey protein isolate/soybean protein isolate (WPI/SPI) composite particles were used as a template to construct Pickering emulsion gel (PEG). The ...results showed that the PE stabilized by WPI/SPI composite particles had good centrifugal and storage stability at 4 °C (at least 4 months). Furthermore, When SA concentration was 3% and PE:SA ratio of 5:1, the obtained PEG with water-in-oil type exhibited a smaller droplet size, a denser network structure, and solid-like behavior in the linear viscoelastic region using a laser particle size analyzer, rheometer, and confocal laser scanning microscopy. Moreover, the increase of hydrogen bonds after SA addition confirmed that increased of β-sheet in WPI/SPI by Fourier-transform infrared spectroscopy, as β-sheet structure was stabilized by interchain hydrogen bonds, thus forming a denser network structure. In addition, PEGs could effectively encapsulate peptide FDRPFL, with a highest encapsulation efficiency of 72.8%. In vitro digestion behavior revealed that PEGs could improve the bioaccessibility of peptide FDRPFL and mainly followed the release mechanism of non-Fickian superstate II. Taken together, the present findings provide a theoretical framework for the development and application of PEGs stabilized by WPI/SPI composite particles.
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•The Pickering emulsion stabilized by WPI/SPI composite particles had good stability at 4 °C.•SA and WPI/SPI composites enhanced Pickering emulsion gels' structure via hydrogen bonds.•Pickering emulsion gels could improved bioaccessibility of peptide FDRPFL.•FDRPFL release from Pickering emulsion gels followed a non-Fickian diffusion.
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•A flexible self-standing composite film anode is prepared by vacuum filtration.•The film anode can effectively inhibit zinc dendrites and parasitic side reactions.•The film anode ...contributes to significantly improved electrochemical performance.•A flexible integrated battery is constructed using a layer-by-layer method.•The integrated battery exhibits superior performance even under bending.
With the booming development of wearable electronics, flexible zinc-based batteries are attracting significant attention due to their high safety, low cost, environmental benignity, and relatively large energy/power densities. However, in a conventional segregated configuration, the electrodes could be easily detached from the separator when the battery is subjected to bending strain, which would dramatically depress electrochemical performances. Moreover, severe zinc dendrite growth and parasitic side reactions at the anode are extremely detrimental to the durability and the reliability of zinc-based batteries. Herein, a flexible self-standing composite film anode consisting of zinc microspheres, carbon nanotubes, and nanocellulose is constructed to replace the conventional Zn foil. It is found that the use of this anode can effectively inhibit the dendrites and side reactions, thereby substantially improving the cyclability. In addition, a layer-by-layer vacuum filtration method is used to integrate the composite film anode with a cellulose separator and a MnO2-based composite film cathode into a single matrix. The unique integrated battery realizes great rate capability and cycling stability, and more importantly, superior affordability to bending deformations. Besides, the commonly used thick, heavy, and expensive current collectors are no longer required in the integrated configuration, therefore enabling the battery to be smarter and cheaper. This study not only opens a new option for building dendrite-free zinc anodes but also discloses a facile strategy to achieve integrated configuration for energy storage devices.
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•A novel antimicrobial peptide (MOp3) was isolated and identified from M. oleifera seeds.•MOp3 exhibited potent antimicrobial activity and negligible hemolytic activity.•MOp3 induced ...irreversible damage on cell membrane of Staphylococcus aureus.•MOp3 interacted with DNA gyrase and dihydrofolate reductase of S. aureus.
This study aimed to characterize a novel antimicrobial peptide (AMP) obtained from Moringa oleifera seed protein hydrolysates. Cell membrane chromatography and live bacteria adsorption were combined into a single step to efficiently isolate the active fraction of the AMP. Five peptides were identified by LC-MS/MS, among which the MCNDCGA peptide (termed MOp3) showed the greatest inhibitory effect against Staphylococcus aureus minimum inhibitory concentration (MIC): 2 mg/mL. MOp3 was identified as a hydrophobic anionic AMP rich in β-sheet structures with negligible hemolytic activity at 2.0 × MIC. MOp3 had good tolerance to salt solutions at 5 % and pH range 6.0–8.0, but was sensitive to high temperatures (>100 °C) and acid protease. Microscopic observation further revealed that MOp3 induced irreversible damage onto the cell membrane of S. aureus and interacted with dihydrofolate reductase and DNA gyrase by hydrogen bonding and hydrophobic interaction. These findings highlight the potential application of a new antimicrobial agent against S. aureus in the food industry.
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•The synthesis of PLA in L. plantarum L3 was regulated by LuxS/AI-2 QS.•1291 differentially expressed proteins were identified in the synthesis of PLA.•LuxS, araT, and ldh are key ...proteins affecting the synthesis of PLA in L. plantarum L3.•The central pathway in L. plantarum L3 is the PLA synthesis from phenylalanine.
The phenyllactic acid (PLA) produced by lactic acid bacteria (LAB) inhibits fungi and facilitates the quality control of fermented milk. A strain of Lactiplantibacillus plantarum L3 (L. plantarum L3) with high PLA production was screened in the pre-laboratory, but the mechanism of its PLA formation is unclear. The amount of autoinducer-2 (AI-2) increased with increasing culture time, as did cell density and PLA. The results in this study suggest that PLA production in L. plantarum L3 may be regulated by the LuxS/AI-2 Quorum Sensing (QS) system. Tandem mass tag (TMT) quantitative proteomics analysis showed that a total of 1291 differentially expressed proteins (DEPs) were quantified in the incubated for 24 h compared with the incubated for 2 h, of which 516 DEPs were up-regulated and 775 DEPs were down-regulated. Among them, S-ribosomal homocysteine lyase (luxS), aminotransferase (araT), and lactate dehydrogenase (ldh) are the key proteins for PLA formation. The DEPs were mainly involved in the QS pathway and the core pathway of PLA synthesis. Furanone effectively inhibited the production of L. plantarum L3 PLA. In addition, Western blot analysis demonstrated that luxS, araT, and ldh were the key proteins regulating PLA production. This study reveals the regulatory mechanism of PLA based on the LuxS/AI-2 QS system, which provides a theoretical basis for the efficient and large-scale production of PLA in industries in the future.
Flexible aqueous zinc-ion batteries are promising to satisfy the booming wearable electronics. Herein, a facile, scalable, and cost-effective method (one-step electrodeposition) is developed to grow ...MnO2 nanoflakes onto carbon nanotube (CNT) film. The binder-free self-supporting CNT@MnO2 film can take advantages of highly conductive CNT scaffold and nanostructure of MnO2, thus leading to facilitated electrochemical kinetics. Based on the CNT@MnO2 film, a flexible quasi-solid-state Zn-MnO2 battery is assembled and achieves high reversible capacity of 292.7 mAh g−1 (corresponding to 16.5 mWh cm−3) at 0.2 mA cm−2, great rate capability (105.6 mAh g−1 at 3 mA cm−2), and excellent cycling stability (no capacity fading after 1000 cycles). The quasi-solid-state Zn-MnO2 battery also shows high tolerance to mechanical bending. With these merits, the CNT@MnO2 film holds great potential for Zn-MnO2 batteries to power wearable electronics.
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•A facile one-step electrodeposition is used to grow α-MnO2 nanoflakes on CNT film.•The product shows fast electrochemical kinetics and high Zn2+ diffusion coefficient.•A flexible quasi-solid-state aqueous zinc ion battery is assembled.•High specific capacity, great rate capability, and excellent cyclability are obtained.•The battery exhibits high tolerance to mechanical bending.
In this study, label-free quantitative proteomics was used to investigate the biological functions of M. oleifera seed proteins, which resulted in the identification of milk-clotting proteases. In ...total, 921 proteins were identified, and proteins within the molecular weight range of 30–50 kDa were abundant. The identified proteins were mainly involved in catalytic activity and metabolic processes associated with carbohydrate and protein metabolism, among which, proteases in the observed molecular weight range could possibly be responsible for the previously reported milk-clotting activity. An aspartic-type endopeptidase with molecular mass of 45,517 Da was purified from M. oleifera seeds using ammonium sulfate precipitation, ultrafiltration, and preparative high performance liquid chromatography, and was characterized using liquid chromatography-mass spectrometry (LC-MS)/MS. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that the purified protease exhibited hydrolase activity and was involved in several metabolic pathways, which further confirmed that proteomic analysis can assist in the purification of the milk-clotting protease. The optimal temperature and pH required for protease activity were 60 °C and 5.0, respectively. The high thermal stability and good pH stability of the protease indicated that it can be used in the dairy industry.
•Proteomics was used to investigate the biological functions of M. oleifera seeds.•Proteases of 30–50 kDa were possibly responsible for the milk-clotting activity.•An aspartic-type endopeptidase with molecular mass of 45,517 Da was purified.•Proteomic analysis can assist in the purification of the milk-clotting protease.•The protease exhibited high thermal stability and good pH stability.
