Food-derived peptides unleashed: emerging roles as food additives beyond bioactivities.

Innovating food additives stands as a cornerstone for the sustainable evolution of future food systems. Peptides derived from food proteins exhibit a rich array of physicochemical and biological attributes crucial for preserving the appearance, flavor, texture, and nutritional integrity of foods. Leveraging these peptides as raw materials holds great promise for the development of novel food additives. While numerous studies underscore the potential of peptides as food additives, existing reviews predominantly focus on their biotic applications, leaving a notable gap in the discourse around their abiotic functionalities, such as their physicochemical properties. Addressing this gap, this review offers a comprehensive survey of peptide-derived food additives in food systems, accentuating the application of peptides' abiotic properties. It furnishes a thorough exploration of the underlying mechanisms and diverse applications of peptide-derived food additives, while also delineating the challenges encountered and prospects for future applications. This well-time review will set the stage for a deeper understanding of peptide-derived food additives.

Multiple analyses of main flavor components in reconstituted tobacco and transfer behavior of their key substances during heating.

Reconstituted tobacco (RT) is a product made by reprocessing tobacco waste, experiencing a growing demand for heat-not-burn products. The purpose of this study is to analyze the main flavor ingredients in RT aerosol, as well as the transfer behavior of key flavor substances from substrates to aerosol and the concentrations of these compounds in the substrate after heating. First, we demonstrated that the odor of four RT aerosol samples could be distinguished using an electronic nose. Through non-targeted analysis, 93 volatile compounds were detected by gas chromatography-mass spectrometry, and 286 non/semi-volatile compounds were identified by ultra-high-performance liquid electrophoresis chromatography-mass spectrometry in aerosol. Furthermore, we found that the formation of RT aerosol involves primarily evaporation and distillation, however, the total content delivered from unheated RT samples to aerosol remains relatively low due to compound volatility and cigarette filtration. Thermal reactions during heating indicated the pyrolysis of chlorogenic acid to generate catechol and resorcinol, while Maillard reactions involving glucose and proline produced 2,3-dihydro-3,5-dihydroxy-6-methyl-4h-pyran-4-one. The study highlighted that heating RT at approximately 300°C could mitigate the production of harmful substances while still providing a familiar sensory experience with combusted tobacco.

Investigation of γ-polyglutamic acid production via asynchronous saccharification and fermentation of raw corn starch.

Starch, a crucial raw material, has been extensively investigated for biotechnological applications. However, its application in γ-polyglutamic acid (γ-PGA) production remains unexplored. Based on γ-PGA output of Bacillus subtilis SCP010-1, a novel asynchronous saccharification and fermentation process for γ-PGA synthesis was implemented. The results revealed that a starch concentration of 20%, α-amylase dosage of 75 U/g, liquefaction temperature of 72℃, and γ-PGA yield of 36.31 g/L was achieved. At a glucoamylase dosage of 100 U/g, saccharification 38 h at 60℃, the yield of γ-PGA increased to 48.88 g/L. The contents of total sugar, glucose, maltose and oligosaccharide in saccharified liquid were determined. Through batch fermentation of saccharified liquid in fermentor, the γ-PGA output was elevated to 116.08 g/L. This study can offer a potential cost reduction of 40%, which can be a promising advancement in industrial γ-PGA production. Moreover, our approach can be applied in other starch-based fermentation industries.

[Evaluation of chemical constituents of Draconis Sanguis and its protective effect on renal tubular injury in diabetic kidney disease].

The chemical constituents of Draconis Sanguis were preliminarily studied by macroporous resin, silica gel, dextran gel, and high-performance liquid chromatography. One retro-dihydrochalcone, four flavonoids, and one stilbene were isolated. Their chemical structures were identified as 4-hydroxy-2,6-dimethoxy-3-methyldihydrochalcone(1), 4'-hydroxy-5,7-dimethoxy-8-methylflavan(2), 7-hydroxy-4',5-dimethoxyflavan(3),(2S)-7-hydroxy-5-methoxy-6-methylflavan(4),(2S)-7-hydroxy-5-methoxyflavan(5), and pterostilbene(6) by modern spectroscopy, physicochemical properties, and literature comparison. Compound 1 was a new compound. Compounds 2 and 6 were first found in the Arecaceae family. Compound 5 had the potential to prevent and treat diabetic kidney disease.

Characterization and mutagenesis of a novel Mycobacterium smegmatis-derived glutamate decarboxylase active at neutral pH.

γ-aminobutyric acid (GABA) has various physiological functions and is widely used in medicine, food, and other fields. Glutamate decarboxylase (GAD) is a key enzyme that catalyzes the decarboxylation of L-glutamate to synthesize GABA. However, the industrial application of microorganism-derived GAD is limited by its rapid loss of enzymatic activity with pH approaching neutrality. In this study, a novel glutamate decarboxylase, GADMSM, from Mycobacterium smegmatis was overexpressed and purified. On the basis of homologous modeling and substrate molecular docking, several GADMSM mutants were constructed, and their enzymatic properties were analyzed. The results showed that the optimal pH of wild-type GADMSM is 5.4; at pH 6.2, 22.8% enzymatic activity was retained. The T211I replacement in GAD and C-terminal deletion mutant GADMSMΔC showed relatively high catalytic activity in a pH range of 5.0-7.0. The Vmax and Km values of GADMSMΔC were 14.69 and 5.70, respectively, at pH 5.5, and 9.87 and 6.17, respectively, at pH 7.0. Compared with the wild-type GAD, GADMSMΔC maintained higher affinity and enzymatic activity of the substrate, maintaining 78.5% of the highest enzymatic activity even at pH 7.0, which is the highest reported activity retention for GAD under neutral pH condition. Therefore, GADMSMΔC can be used for the transformation of high-yielding strains and industrial production of GABA.

[Therapeutic effects of alkaloids in Tibetan medicine Bangna (Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis rats and mechanisms].

This study aims to investigate the therapeutic effects of alkaloids in Tibetan medicine Bangna(Aconiti Penduli et Aconiti Flavi Radix) on osteoarthritis(OA) rats in vitro and in vivo and the underlying mechanisms. Chondrocytes were isolated from 2-3 week-old male SD rats and lipopolysaccharide(LPS) was used to induce OA in chondrocytes in vitro. Methyl thiazolyl tetrazolium(MTT) assay was used to investigate the toxicity of seven alkaloids(12-epi-napelline, songorine, benzoylaconine, aconitine, 3-acetylaconitine, mesaconitine, and benzoylmesaconine) to chondrocytes. Chondrocytes were classified into the control group, model group(induced by LPS 5 µg·mL~(-1) for 12 h), and administration groups(induced by LPS 5 µg·mL~(-1) for 12 h and incubated for 24 h). The protein expression of inflammatory factors cyclooxygenase-2(COX-2), inducible nitric oxide synthetase(iNOS), tumor necrosis factor-α(TNF-α), and interleukin-1ß(IL-1ß) in each group were detected by Western blot, and the protein expression of matrix metalloprotease-13(MMP-13), aggrecan, collagen Ⅱ, fibroblast growth factor 2(FGF2) by immunofluorescence staining. For the in vivo experiment, sodium iodoacetate was used to induce OA in rats, and the expression of MMP-13, TNF-α, and FGF2 in cartilage tissues of rats in each group was detected by immunohistochemistry. The results showed that the viability of chondrocytes could reach more than 90% under the treatment of the seven alkaloids in a certain dose range. Aconitine, 12-epi-napelline, songorine, 3-acetylaconitine, and mesaconitine could decrease the protein expression of inflammatory factors COX-2, iNOS, TNF-α and IL-1ß compared with the model group. Moreover, 12-epi-napelline, aconitine, and mesaconitine could down-regulate the expression of MMP-13 and up-regulate the expression of aggrecan and collagen Ⅱ. In addition, compared with the model group and other Bangna alkaloids, 12-epi-napelline significantly up-regulated the expression of FGF2. Therefore, 12-epi-napelline was selected for the animal experiment in vivo. Immunohistochemistry results showed that 12-epi-napelline could significantly reduce the expression of MMP-13 and TNF-α in cartilage tissues, and up-regulate the expression of FGF2 compared with the model group. In conclusion, among the seven Bangna alkaloids, 12-epi-napelline can promote the repair of OA in rats by down-regulating the expression of MMP-13 and TNF-α and up-regulating the expression of FGF2.

Metamaterial-like aerogels for broadband vibration mitigation.

We report a mechanical metamaterial-like behavior as a function of the micro/nanostructure of otherwise chemically identical aliphatic polyurea aerogels. Transmissibility varies dramatically with frequency in these aerogels. Broadband vibration mitigation is provided at low frequencies (500-1000 Hz) through self-assembly of locally resonant metastructures wherein polyurea microspheres are embedded in a polyurea web-like network. A micromechanical constitutive model based on a discrete element method is established to explain the vibration mitigation mechanism. Simulations confirm the metamaterial-like behavior with a negative dynamic material stiffness for the micro-metastructured aerogels in a much wider frequency range than the majority of previously reported locally resonant metamaterials.

Novel Podophyllotoxin Derivatives as Potential Tubulin Inhibitors: Design, Synthesis, and Antiproliferative Activity Evaluation.

A number of podophyllotoxin derivatives (3A-3J) had been designed and synthesized, and their biological activities were evaluated in this study. Moreover, the antiproliferation activities of these compounds against four human cancer cell lines (HepG2, HeLa, A549, and MCF-7) were also tested. The results indicated that the most promising compound 3D displayed potent inhibitory activity over the four human cancer cell lines and was further demonstrated to have potent tubulin polymerization inhibitory effects without damaging the non-cancer cells. Additionally, 3D was verified to effectively interfere with tubulin and could prevent the mitosis of cancer cells, leading to cell cycle arrest and eventually inducing apoptosis in a dose- and time-dependent manner. Moreover, the Western blotting and siRNA results showed that Bcl-2 was downregulated in HepG2 cells treated with 3D. Finally, the molecular docking simulation results revealed that 3D could fit well in the colchicine-binding pocket. Taken together, this study has provided certain novel antitubulin agents for possible cancer chemotherapy.

[ITS2 sequence analysis and identification of medicinal Artemisia plants].

Artemisia hedinii occupies an important position in the Tibetan medicine. Plants in Artemisia vary a lot and are widely distributed in the Qinghai-Tibet Plateau, many plants in Artemisia look similar, making traditional identification methods laborious. In this article, ITS2 sequences were used as DNA barcoding to identify four kinds of confusable Tibetan medicine plants in Artemisia, aiming to establish a rapid and accurate identification methods. Twenty-one samples in Artemisia were collected from the Qinghai-Tibet Plateau, ITS2 sequence PCR amplification and sequencing were conducted after the extraction of DNA. Another 11 sequence downloaded from Genbank were added to the analysis. Genetic distance calculation and analysis, building Neighbor Joining (NJ) phylogenetic tree were conducted by MEGA 6.0, also comparison of secondary structures of ITS2 sequences among samples. A. hedinii, A. annua, A. dubia and A. argyi shared close genetic distance, but the maximum distance between the four species was much greater than the minimum distance within each species, NJ tree showed that the four species went to four separate branches, differences among secondary structures of ITS2 sequences also made it clear to identify these medical plants. It could be an accurate and rapid method for identification and recognition, as well as the evolutionary relationships between the species by using ITS2 sequence as DNA barcode for plants of Tibetan Artemisia. The study provides theoretical basis for quality control, medication safety and rational exploitation.

Identification and characterization of novel anticoagulant peptide with thrombolytic effect and nutrient oligopeptides with high branched chain amino acid from Whitmania pigra protein.

Natural and nutrient substances for cardiovascular disease are promising and capture researchers' minds. Two kinds of novel bioactive peptides (high Fischer's ratio oligopeptides and anticoagulant peptides) were obtained from Whitmania pigra protein via enzymatic hydrolysis. An oligopeptide (MW<874.0 Da) named as HF2 was obtained via chromatography purification procedures with a high Fischer's ratio of 31.92 ± 1.36 and low phenylalanine + tyrosine content of 0.98 ± 0.04 %. Another peptide (WA3-1), prepared by alcalase AF 2.4 L-catalyzed hydrolysis and then purified by DEAE Sepharose FF, gel Sephadex G-15 chromatography, exhibited high anticoagulant activity with prolonging significantly plasma clotting time on activated partial thromboplastin time, prothrombin time, thrombin time (p < 0.01) and powerful thrombolytic activity. Amino acid composition and MALDI-TOF/TOF MS analysis showed that WA3-1 contained 11 amino acids (MW: 1422.0 Da) with the sequence as NH2-His-Asp-Phe-Leu-Asn-Asn-Lys-Leu-Glu-Tyr-Glu-COOH. Abundant negatively charged amino acids in C-terminal, as well as the special residue Lys contribute to its anticoagulant capacity. This research provided a novel natural candidate for the manufacture of nutrient oligopeptides with high branched chain amino acid, and anticoagulant thrombolytic agent in pharmaceutical industry with helping prevent from thrombosis and related cardiovascular diseases.

Visualizing detecting low-frequency underwater acoustic signals by means of optical diffraction.

A novel and simple technique based on the light diffraction effect for visualization of low-frequency underwater acoustic waves (LFUAWs) in real time has been developed in this paper. A cylindrical object has been put on the surface of the water. A low-frequency underwater longitudinal wave can be generated into a water surface transversal capillary wave around the cylinder by our technique. Modulating the phase of a laser beam reflected from a water surface by surface acoustic waves (SAWs) realizes the acousto-optic effect. Then, a steady and visible diffraction pattern is experimentally observed. A physical model of the SAW is established to verify the feasibility of our technique. An analytical expression of wavelength, wave amplitude, and excitation frequency has been derived to study the physical properties of LFUAWs, and it explains the experimental phenomenon very well. As a result, the technique is effective, easy, and practical for visualizing LFUAWs and has significance for applications.

Therapeutic efficacy of classic Tibetan formulas combined at different hours in resisting cerebral ischemia.

The study focused on the therapeutic efficacy of Tibetan medicines on cerebral ischemia. The combined medication methods and administration habits in clinic for more than 10 years were simulated. Three typical Tibetan medicines, i.e., 25-Herb Shanhu pill, Wishful-Treasure pill and 20-Herb Chenxiang pill, were administered to the animal model of permanent middle cerebral artery occlusion in the morning, noon and evening, respectively. On the second day after the final administration, the activity of serum oxidative stress marker SOD and the content of MDA were evaluated. Infarct volumes were quantified through TTC staining. Inflammatory reaction maker NF-kappaB p65 gene and apoptosis. makers Bax and Cyct were selected to study the molecular mechanism of combined herbs with the immunohistochemistry technique. According to the result, the respective combination of 25-Herb Shanhu pill, Wishful-Treasure pill and 20-Herb Chenxiang pill in the morning, noon and evening showed unique advantages in reducing the damage of oxidative stress, infarct volumes, encephaledema caused by ischemia, inflammatory factor aggregation and inhibiting apoptosis, with consistent therapeutic efficacies in clinic.

[Identification and analysis of Corydalis boweri, Meconopsis horridula and their close related species of the same genus by using ITS2 DNA barcode].

The study is aimed to ensure the quality and safety of medicinal plants by using ITS2 DNA barcode technology to identify Corydalis boweri, Meconopsis horridula and their close related species. The DNA of 13 herb samples including C. boweri and M. horridula from Lhasa of Tibet was extracted, ITS PCR were amplified and sequenced. Both assembled and web downloaded 71 ITS2 sequences were removed of 5. 8S and 28S. Multiple sequence alignment was completed and the intraspecific and interspecific genetic distances were calculated by MEGA 5.0, while the neighbor-joining phylogenetic trees were constructed. We also predicted the ITS2 secondary structure of C. boweri, M. horridula and their close related species. The results showed that ITS2 as DNA barcode was able to identify C. boweri, M. horridula as well as well as their close related species effectively. The established based on ITS2 barcode method provides the regular and safe detection technology for identification of C. boweri, M. horridula and their close related species, adulterants and counterfeits, in order to ensure their quality control, safe medication, reasonable development and utilization.

Purification and characterization of high antioxidant peptides from duck egg white protein hydrolysates.

The hydrolysate from duck egg white protein (DEWP) prepared by "SEEP-Alcalase" at degree of hydrolysis (DH) value of 21% (namely HSA21) exhibited high antioxidant capacity in different oxidation systems. A consecutive chromatographic method was then developed for separation and purification of HSA21, including ion-exchange chromatography, macroporous adsorption resin (MAR) and gel filter chromatography. The final peptides "P21-3-75-B" were obtained with significantly enhanced antioxidant activity (p<0.05). It was further confirmed that the product mainly consisted of five oligopeptides (Mr: 202.1, 294.1, 382.1, 426.3, and 514.4Da). Furthermore, the antioxidant activity of P21-3-75-B kept stable after in vitro digestive simulation. Antioxidant capacity of the purified peptides was closely related to the molecular mass, hydrophobic amino acid residues, acidic amino acid and some antioxidant amino acids. This research provided a valuable route for producing new natural-source peptides with strong antioxidant capacity and high nutritious value for our daily intake.

Overexpression of SAMD9 suppresses tumorigenesis and progression during non small cell lung cancer.

The Sterile Alpha Motif Domain-containing 9 (SAMD9) gene has been recently emphasized during the discovery that it is expressed at a lower level in aggressive fibromatosis and some cases of breast and colon cancer, however, the underlying mechanisms are poorly understood. Here, we found that SAMD9 is down-regulated in human non-small cell lung cancer (NSCLC). Furthermore, knockdown of SAMD9 expression is increased the invasion, migration and proliferation in H1299 cells in vitro and overexpression of SAMD9 suppressed proliferation and invasion in A549 cells. Finally, depletion of SAMD9 increases tumor formation in vivo. Our results may provide a strategy for blocking NSCLC tumorigenesis and progression.

Identification of gene expression profiles in the actinomycete Gordonia neofelifaecis grown with different steroids.

Gordonia neofelifaecis NRRL B-59395 was initially isolated from the fresh feces of a clouded leopard based on its ability to degrade cholesterol. The transcriptome profiles of G. neofelifaecis NRRL B-59395 grown with cholesterol, androstenedione (AD), and pyruvic acid were compared by RNA-Seq. The sterol catabolic genes are highly conserved in G. neofelifaecis, Rhodococcus jostii RHA1, and Mycobacterium tuberculosis. The RNA-Seq results indicated that the genes involved in the sterol side chain cleavage were exclusively induced by cholesterol, while the genes involved in the degradation of rings A/B and C/D were up-regulated by both cholesterol and AD. It appears that the induction mechanisms for the genes responsible for side chain cleavage and those for degradation of rings are different. There are approximately 21 genes encoding transporter proteins that are differentially expressed in cholesterol or AD compared with pyruvic acid. The genes camABCD and camM encode two systems that take up cholate, and they have been shown to be cholesterol- and AD-inducible. The potential biological functions of other differentially expressed genes are also discussed. These results will promote the functional characterization of the sterol catabolic genes and also provide important clues in understanding the mechanisms of their gene expression, and they may help us understand the mechanism underlying microbial cholesterol catabolism.

Using ionic liquids in whole-cell biocatalysis for the nucleoside acylation.

BACKGROUND: The use of biocatalysts has become an increasingly attractive alternative to traditional chemical methods, due to the high selectivity, mild reaction conditions and environmentally-friendly processes in nonaqueous catalysis of nucleosids. However, the extensive use of organic solvents may generally suffer from sever drawbacks such as volatileness and toxicity to the environment and lower activity of the biocatalyst. Recently, ionic liquids are considered promising solvents for nonaqueous biocatalysis of polyhydroxyl compounds as ILs are environmental-friendly. RESULTS: In this research, we developed new IL-containing reaction systems for synthesis of long chain nucleoside ester catalyzed by Pseudomonas fluorescens whole-cells. Various ILs exerted significant but different effects on the bio-reaction. And their effects were closely related with both the anions and cations of the ILs. Use of 10% [BMI][PF6]/THF gave high reaction efficiency of arabinocytosine laurate synthesis, in which the initial rate, product yield and 5'-regioselectivity reached 2.34 mmol/L·h, 81.1% and >99%, respectively. Furthermore, SEM analysis revealed that ILs can alter the cell surface morphology, improve the permeability of cell envelopes and thus facilitate the mass transfer of substrates to the active sites of cell-bound enzymes. CONCLUSION: Our research demonstrated the potential of ILs as promising reaction medium for achieving highly efficient and regioselective whole-cell catalysis.

Dendrite Growth and Dead Lithium Formation in Lithium Metal Batteries and Mitigation Using a Protective Layer: A Phase-Field Study.

Lithium metal batteries (LMBs) are considered one of the most promising next-generation rechargeable batteries due to their high specific capacity. However, severe dendrite growth and subsequent formation of dead lithium (Li) during the battery cycling process impede its practical application. Although extensive experimental studies have been conducted to investigate the cycling process, and several theoretical models were developed to simulate the Li dendrite growth, there are limited theoretical studies on the dead Li formation, as well as the entire cycling process. Herein, we developed a phase-field model to simulate both electroplating and stripping process in a bare Li anode and Li anode covered with a protective layer. A step function is introduced in the stripping model to capture the dynamics of dead Li. Our simulation clearly shows the growth of dendrites from a bare Li anode during charging. These dendrites detach from the bulk anode during discharging, forming dead Li. Dendrite growth becomes more severe in subsequent cycles due to enhanced surface roughness of the Li anode, resulting in an increasing amount of dead Li. In addition, it is revealed that dendrites with smaller base diameters detach faster at the base and produce more dead lithium. Meanwhile, the Li anode covered with a protective layer cycles smoothly without forming Li dendrite and dead Li. However, if the protective layer is fractured, Li metal preferentially grows into the crack due to enhanced Li-ion (Li+) flux and forms a dendrite structure after penetration through the protective layer, which accelerates the dead Li formation in the subsequent stripping process. Our work thus provides a fundamental understanding of the mechanism of dead Li formation during the charging/discharging process and sheds light on the importance of the protective layer in the prevention of dead Li in LMBs.

Multiplexing Imaging of Closely Located Single-Nucleotide Mutations in Single Cells via Encoded in situ PCR.

Mutation accumulation in RNAs results in closely located single-nucleotide mutations (SNMs), which is highly associated with the drug resistance of pathogens. Imaging of SNMs in single cells has significance for understanding the heterogeneity of RNAs that are related to drug resistance, but the direct "see" closely located SNMs remains challenging. Herein, we designed an encoded ligation-mediated in situ polymerase chain reaction method (termed enPCR), which enabled the visualization of multiple closely located SNMs in bacterial RNAs. Unlike conventional ligation-based probes that can only discriminate a single SNM, this method can simultaneously image different SNMs at closely located sites with single-cell resolution using modular anchoring probes and encoded PCR primers. We tested the capacity of the method to detect closely located SNMs related to quinolone resistance in the gyrA gene of Salmonella enterica (S. enterica), and found that the simultaneous detection of the closely located SNMs can more precisely indicate the resistance of the S. enterica to quinolone compared to the detection of one SNM. The multiplexing imaging assay for SNMs can serve to reveal the relationship between complex cellular genotypes and phenotypes.

Generalization of cut-in pre-crash scenarios for autonomous vehicles based on accident data.

The utilization of high-risk test cases constitutes an effective approach to enhance the safety testing of autonomous vehicles (AVs) and enhance their efficiency. This research paper presents a derivation of 2052 high-hazard pre-crash scenarios for testing autonomous driving, which were based on 23 high-hazard cut-in accident scenarios from the National Automobile Accident In-Depth Investigation System (NAIS) through combining importance sampling and combined testing methods. Compared to the direct combination of the original distribution after sampling, the proposed method has a 2.92 times higher crash rate of 69.32% for the test case set in this paper. It also has a 5.8 times higher rate of triggering Automatic Emergency Braking (AEB), improving hazardous scenario coverage. Using the proposed method, the generated parameters of the cut-in accident scenario test set were compared with those of the cut-in test scenarios included in existing Chinese autonomous driving test protocols and standards. The velocity of the ego-vehicle obtained using the proposed method matched those in the existing protocols, whereas the velocity, time gap, and time to collision of the target vehicle were significantly lower than those existing protocols indicating scenarios obtained from accident data can enrich the selection of testing scenarios for autonomous driving.