Aspartate Research Articles

Study on common amino acid pyrolysis products and analysis of pyrolysis products from interaction with aspartic acid

Nitrogen in nitrogen-rich biomass can be converted into high-value nitrogen-containing chemicals such as pyrroles, pyridines and indoles by pyrolysis. Understanding the nitrogen transport mechanism and reaction pathways is important for the utilization of nitrogen-rich biomass. In this study, the pyrolytic reaction pathways of 16 amino acids and interaction between others with aspartic acid were analyzed by pyrolysis in a closed U-tube reactor followed by gas chromatography/mass spectrometry (GC/MS) measurements. It was found that amino acids with lighter molecular tended to produce more gases during the pyrolysis, while amino acids with heavier molecular tended to produce more liquids and solids. The gaseous products of amino acid pyrolysis mainly consisted of CO2 and some CO, of which the content of CO2 reached 86.21% of glycine and 70.97% of aspartic acid, respectively. Liquid oils contain a large number of nitrogen-containing heterocyclic compounds, which are mainly produced by four types of reactions: cyclisation, R group removal, polymerization, and fragmentation reforming. And it was found that aspartic acid was able to promote the changes of the three phases of pyrolysis products and the formation of characteristic products.

Biomolecule-functionalized exfoliated-graphene and graphene oxide as heteronucleants of nanocrystalline apatites to make hybrid nanocomposites with tailored mechanical, luminescent, and biological properties

Nanocrystalline apatite (Ap), known for its exceptional biological properties, faces limitations in hard tissue engineering due to its poor mechanical properties. To overcome this limitation, we investigated the preparation of nanocomposites through heterogeneous nucleation of calcium phosphate on exfoliated graphene (G) and graphene oxide (GO) flakes, selected for their outstanding mechanical properties. The flakes were treated (functionalized) with amino acids of varying isoelectric points—namely L-Arginine (Arg), L-Alanine (Aln) and L-Aspartic acid (Asp)— as well as citrate (Cit) molecules. Furthermore, Tb3+ was incorporated into the formulations to introduce luminescence and further enrich the functionality of the composite. The synthesis was conducted using the sitting drop vapor diffusion method. Functionalized GO/Ap nanocomposites significantly improved roughness, adhesion forces and elastic modulus compared to Ap and G-based particles. GO-Asp-Ap-Tb nanocomposites exhibited the highest roughness (163.8 ± 116.2 nm), while G-Cit-Ap had the lowest (6.8 ± 5.6 nm). In terms of adhesion force, GO-Cit-Ap-Tb reached the highest value (31.06 ± 13.3 nN), while G-Arg-Ap had the lowest (3.7 ± 1.8 nN) compared to Ap (13.6 ± 3.2 nN). For the elastic modulus, GO-Aln-Ap-Tb demonstrated the greatest stiffness (3489 ± 101.01 MPa) compared to Ap (30.2 ± 6.5 MPa), while G-Aln-Ap-Tb showed the lowest (17.2 ± 8.4 MPa). Concerning their luminescence, regardless of G/Ap and GO/Ap, the relative luminescence intensities depended on the biomolecule used and decreased in the order Arg > Aln >Asp and Cit. Furthermore, G/Ap and GO/Ap nanocomposites demonstrated good biocompatibility on murine mesenchymal stem cells at low concentrations, showing cell viabilities exceeding 80% at 0.1 μg/mL. This research offers a novel approach to enhancing the mechanical properties of apatites while preserving their good biocompatibility properties and introducing new functionalities (i.e. luminescence) in the composites, thereby expanding their range of applications in hard tissue engineering.

Heterozygous DSP in-frame deletion in a poodle with syndromic ichthyosis involving additional hair and tooth abnormalities.

Ichthyoses comprise a large heterogeneous group of skin disorders, characterized by generalized scaly and hyperkeratotic skin. We investigated a miniature poodle with early onset generalized scaling, dry and irregularly thickened skin, paw pad hyperkeratosis and abnormalities in hair and teeth. The clinical signs of ichthyosis were confirmed by histopathological examination, which revealed mild epidermal hyperplasia and lamellar orthokeratotic hyperkeratosis. A hereditary condition was suspected and a genetic investigation was initiated. We sequenced the whole genome of the affected dog and searched for potentially causative variants in functional candidate genes for the observed phenotype. The analysis revealed a heterozygous in-frame deletion in DSP, NC_049256.1:g.8804542_8804544del resulting from a de novo mutation event as evidenced by genotyping leukocyte DNA from both parents. The 3 bp deletion is predicted to remove one aspartic acid without disrupting the open reading frame (XM_038584124.1:c.1821_1823del, XP_038440052.1:p.(Asp608del)). The DSP gene encodes desmoplakin, a desmosomal plaque protein, responsible for cell-cell adhesion to provide resistance to mechanical stress in epidermal and cardiac tissues. We hypothesize that the deletion of one amino acid in the N-terminal globular head domain acts in a dominant negative manner and thus impairs the proper connection with other proteins. Several variants in DSP in humans and cattle have been described to result in different phenotypes associated with hair and skin abnormalities, sometimes in combination with variable cardiac and/or dental manifestations. In conclusion, we characterized a new syndromic ichthyosis phenotype in a dog and identified a de novo 3 bp deletion in the DSP gene as causal variant.

Volvariella volvacea (paddy straw mushroom): A mushroom with exceptional medicinal and nutritional properties

Volvariella volvacea, commonly referred to as paddy straw mushroom, is renowned for its remarkable medicinal and nutritional properties. This mushroom, part of the family Pluteaceae, thrives in tropical and subtropical regions and is highly esteemed for its distinctive flavor and substantial health benefits. The fruiting body of V. volvacea is a rich source of bioactive compounds, including antioxidant enzymes, terpenes, polypeptides, sugars, phenolics, and flavonoids. These compounds exhibit an extensive range of therapeutic activities such as anti-tumor, anti-microbial, antioxidant, anti-malarial, anti-cancer, anti-inflammatory, and anti-allergic effects. Nutritionally, V. volvacea is an excellent source of carbohydrates, proteins, fibers, ascorbic acid, and essential minerals. It also boasts a comprehensive profile of amino acids, including valine, arginine, glutamine, serine, aspartic acid, leucine, isoleucine, tyrosine, asparagine, lysine, cystine, proline, glycine, tryptophan, methionine, phenylalanine, threonine, and histidine. This review emphasizes the significant medicinal and nutritional potential of V. volvacea, advocating its inclusion as a functional food to enhance human health and well-being. By highlighting its diverse bioactive compounds and therapeutic benefits, this review aims to foster greater recognition and utilization of paddy straw mushroom in both dietary and medicinal applications.

Biological active compounds from edible mushroom: Effect on hela cells

Background: Mushrooms are unique organisms rich in proteins, carbohydrates, vitamins, and minerals, which allows them to be used not only as a source of nutrition but also in cosmetics and medicine. The fungus P. ostreatus possesses two strong enzymatic complexes – lignin-decaying and cellulose-decaying. Objective: The research aimed to study the antitumor activity of treated mm-wave mycelial extracts of mushrooms on the HeLa cell line. Research on edible mushrooms against tumors is very actual and important for the field of functional food science and bioactive compounds field. Methods: The effect of the fungal culture extract on the cyto-photometric and morphometric indices of the HeLa cell line culture was studied according to the nature of proliferation and transcription of malignant tissues. Using high-resolution liquid chromatography, the amino acid composition of acid-soluble proteins in mycelial extracts of a mushroom culture treated with mm waves was studied. Results: Extracts of P. ostreatus mycelial culture significantly suppressed the growth of proliferative activity of human tumor cultures and completely suppressed the mitotic activity of continuous HeLa cell cultures to 72 hours. Our study revealed a significant increase in glutamic and aspartic acids in mycelial culture extracts treated by mm-waves. Conclusion: Based on HPLC analysis, we suggest polyfunctional peroxidase as the candidate for the role of biologically active compound in the composition of aqueous extracts of the mycelial culture. So, the polyfunctional peroxidase plays an active role in the therapeutic properties of the oyster mushroom. Keywords: anticancer activity, ant-inflammation activity, mm-waves, mushroom`s, mycelial extracts, HPLC of acid-soluble proteins, HeLa cell line.

Bacterial community succession and its correlation with the dynamics of flavor compound during processing of Enshi bacon

Enshi bacon, a famous specialty in Enshi Prefecture, Hu Bei, China, is renowned among customers for the nutritious content and distinct smoky flavor. This study explored the flavor and bacterial flora changes of Enshi bacon during processing and investigated the effect of bacteria on flavor formation. The results showed that the main genera in the pre-processing stage were Brochothrix, Lactococcus and Psychrobacter, which originated from raw meat. Salt-tolerant Staphylococcus and Cobetia were the dominant genera in the late stage of processing. Five free amino acids (aspartic acid, glutamic, alanine, valine, and lysine) were recognized as the flavor substances promoting taste, while aldehydes and phenols were the volatiles that contributed the most to odor. Particularly, compared to the smoking phase, phenolic content increased 2.25-fold at the end of fermentation through microbial action and tyrosine catabolism. The correlation study showed Staphylococcus and Lactococcus as fundamental functional genera that are essential for the formation of bacon flavor. This study provided reference data for the changes in flavor indicators and flora during the processing of Enshi Bacon, revealed the potential mechanism of core functional flora and characteristic flavor formation, and provided a theoretical basis for quality control of the manufacturing process.

Impact of genetic variants on the separation efficiency of β-lactoglobulin during microfiltration of skim milk

Genetic variants of milk proteins are often overlooked by dairy processors as a parameter that can effect process efficiency. This study assessed the impact of the A and B genetic variants of β-lactoglobulin on the isolation of whey proteins from skim milk by microfiltration. The A and B genetic variants of β-lactoglobulin differ by two amino acids at positions 64 (A = aspartic acid, B = glycine) and 118 (A = valine, B = alanine), with the A variant thus having a higher negative charge. Mass balance calculations indicated that 46.7 % more whey proteins permeated during microfiltration for the A compared to the B variant, with the A also having significantly (P < 0.05) more total and reversible fouling accumulation than the B variant. These findings could be of importance to the dairy industry to improve microfiltration efficiency and increase protein yield during manufacture of native whey protein ingredients.

Galloyl–RGD, Derived from a Fusion of Phytochemicals and RGD Peptides, Regulates Photoaging via the MAPK/AP-1 Mechanism in Human Dermal Fibroblasts

Galloyl–RGD is a novel compound that combines gallic acid with RGD peptides (arginine, glycine, and asparaginic acid) to overcome the problems associated with gallic acid, such as instability at high temperatures and low solubility. In this study, we investigated the effects and molecular mechanisms of action of galloyl–RGD on UVB-induced skin photoaging in human dermal fibroblasts-neonatal (HDF-n). Galloyl–RGD increased collagen synthesis by inhibiting UVB-induced MMP-1 via inhibiting extracellular signal-regulated kinase and Jun N-terminal kinase and their downstream mitogen-activated protein kinase signaling, which are known to be representative photoaging mechanisms. The results of this study will be helpful for understanding the anti-photoaging effect and mechanism of galloyl–RGD and its future applications in the cosmetic and pharmaceutical industries.

Effects of water immersion on immune, intestinal flora and metabolome of Chinese mitten crab (Eriocheir sinensis) after air exposure

Air exposure stress can induce stress response of Eriocheir sinensis and affect its normal life activities. The goal of this study was to investigate the effects of water immersion on the recovery of hepatopancreas immune-related enzyme activity, intestinal microbial diversity and metabolic level of Chinese mitten crabs after exposure to air. The results show that immersion can effectively alleviate the adverse effects of air exposure on the antioxidant capacity and immune capacity of Chinese mitten crabs, and the longer the time of immersion, the more obvious the recovery effect. Among them, the levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and acid phosphatase significantly increased after exposure to air (P < 0.05), reached a peak at 3 h, began to decline after immersion, and returned to a level close to the initial value at 24 h (P < 0.05). In addition, after exposure to air, the glucose and total cholesterol in haemolymph of Eriocheir sinensis were significantly different from the initial values (P < 0.05), gradually recovered to the initial level after re-immersion. However, changes in intestinal flora and hepatopancreas metabolism caused by air exposure did not fully recover after water exposure, and its negative effects did not completely disappear. The sequencing results showed that the species composition and diversity of intestinal microorganisms of Chinese mitten crab changed after air exposure and immersion treatment. The relative abundance of Actinomycetes increased significantly, while that of Proteobacteria and Firmicutes decreased significantly. Metabolomics analysis showed that air exposure and immersion destroyed the metabolic balance of amino acids and carnitine, reduced the level of carnitine metabolism, hindered the absorption of nutrients, and led to the accumulation of harmful substances.

Interaction between energy level and starch: fat ratio on intestinal energy metabolism of layer pullets

During the growing period, the gastrointestinal tract of layer pullets is not yet well developed and may be susceptible to dietary energy level. The energy level and composition might impact the intestinal energy metabolism of layer pullets. To test this hypothesis, a total of 480 “Jing Tint 6” layer pullets were used in an 8-week study and allocated to 4 groups, each consisting of 8 replicates, with 15 birds per replicate. Pullets were treated with low or high starch: fat ratios (LS, 10:1; HS, 20:1) in a 2 × 2 factorial arrangement with regular energy (RE, 11.85 and 11.68 MJ/kg for birds from 6 to 10 weeks of age and 11 to 14 weeks of age, respectively) or low energy (LE, 0.55 MJ/kg lower than RE) levels. A significant interaction (P < 0.05) showed that HS increased glandular stomach weight and the jejunal villus length to crypt depth ratio (VCR) in LE diets, but decreased these parameters in RE diets. Dietary energy reduction impaired energy metabolism in the ileum (P < 0.05) mainly via decreasing the gene expression of enzymes involved in the tricarboxylic acid (TCA) cycle (α-ketoglutarate dehydrogenase complex [α-KGDH]; isocitrate dehydrogenase (NAD (+)) [IDH] catalytic; citrate synthase [CS]) and adenosine triphosphate (ATP) synthesis, reducing contents of phosphoenolpyruvate (PEP) and adenylate energy charges (AEC) and down-regulating the adenosine monophosphate-activated protein kinase (AMPK) pathway. HS stimulated AMPKα phosphorylation, increased protein abundance of peroxisome proliferator activated-receptor gamma coactivator 1α (PGC1α) and improved contents of amino acids (aspartate, glutamate, glutamine, alanine and threonine) and malate in the ileum regardless of energy levels (P < 0.05). By an interaction (P < 0.05), the transition from LS to HS diets up-regulated ileal gene expression of AMPKα1 and decreased content of adenosine monophosphate (AMP), accompanied by higher AEC but only in birds fed with LE diets. Collectively, these results suggest that low energy feeding may not be enough for maintaining intestinal energy homeostasis in layer pullets and emphasizes the importance of a relatively high starch: fat ratio in restoring energy metabolism in the ileum.

Engineering Tk1656, a highly active l-asparaginase from Thermococcus kodakarensis, for enhanced activity and stability

l-Asparaginases catalyze the hydrolysis of l-asparagine to l-aspartic acid and ammonia. These enzymes have potential applications in therapeutics and food industry. Tk1656, a highly active and thermostable l-asparaginase from Thermococcus kodakarensis, has been proved effective in selective killing of acute lymphocytic leukemia cells and in reducing acrylamide formation in baked and fried foods. However, it displayed <5 % activity under physiological conditions compared to the optimal activity at 85 °C and pH 9.5. We have attempted engineering of this valuable enzyme to improve the characteristics required for therapeutic and industrial applications. Based on the literature and crystal structure of Tk1656, nine specific mutant variants were designed, produced in Escherichia coli, and the purified mutant enzymes were compared with the wild-type. One of the mutants, K299L, displayed >20 % increase in activity at 85 °C. H158S substitution resulted in >5 °C increase in the optimal temperature. Similarly, a mesophilic-like mutation L56D, resulted in >5-fold increase in activity at pH 7.0 and 37 °C compared to that of the wild-type enzyme. The substrate specificity of the mutant variants remained unchanged. These results demonstrate that L56D and K299L variants of Tk1656 are the potent enzymes for therapeutics and acrylamide mitigation applications, respectively.

Research progress on the regulatory cell death of osteoblasts in periodontitis

Periodontitis is a chronic inflammatory disease characterized by progressive destruction of alveolar bone. The most critical mechanism underlying alveolar bone destruction is the imbalance of bone homeostasis, where osteoblast-mediated bone matrix synthesis plays an important role in regulating bone homeostasis. Regulated cell death is instrumental in both the inflammatory microenvironment and the regulation of bone homeostasis. Chronic inflammation, oxidative stress, and other factors can be directly involved in mitochondrial and death receptor-mediated signaling pathways, modulating B-cell lymphoma 2 family proteins and cysteine aspartic acid specific protease (caspase) activity, thereby affecting osteoblast apoptosis and alveolar bone homeostasis. Chronic inflammation and cellular damage induce osteoblast necroptosis via the RIPK1/RIPK3/MLKL signaling pathway, exacerbating the inflammatory response and accelerating alveolar bone destruction. Stimuli such as pathogenic microorganisms and cellular injury may also activate caspase-1-dependent or independent signaling pathways and gasdermin D family proteins, promoting osteoblast pyroptosis and releasing pro-inflammatory cytokines to mediate alveolar bone damage. Iron overload and lipid peroxidation in periodontitis can trigger ferroptosis in osteoblasts, impacting their survival and function, ultimately leading to bone homeostasis imbalance. This article focuses on the mechanism of periodontal disease affecting bone homeostasis through regulatory cell death, aiming to provide research evidence for the treatment of periodontitis and alveolar bone homeostasis imbalance.

The LAT Rheostat as a Regulator of Megakaryocyte Activation.

Specifically positioned negatively charged residues within the cytoplasmic domain of the adaptor protein, linker for the activation of T cells (LAT), have been shown to be important for efficient phosphorylation of tyrosine residues that function to recruit cytosolic proteins downstream of immunoreceptor tyrosine-based activation motif (ITAM) receptor signaling. LAT tyrosine 132-the binding site for PLC-γ2-is a notable exception, preceded instead by a glycine, making it a relatively poor substrate for phosphorylation. Mutating Gly131 to an acidic residue has been shown in T cells to enhance ITAM-linked receptor-mediated signaling. Whether this is generally true in other cell types is not known. To examine whether LAT Gly131 restricts ITAM signaling in cells of the megakaryocyte lineage, we introduced an aspartic acid at this position in human induced pluripotent stem cells (iPSCs), differentiated them into megakaryocytes, and examined its functional consequences. iPSCs expressing G131D LAT differentiated and matured into megakaryocytes normally, but exhibited markedly enhanced reactivity to glycoprotein VI (GPVI)-agonist stimulation. The rate and extent of LAT Tyr132 and PLC-γ2 phosphorylation, and proplatelet formation on GPVI-reactive substrates, were also enhanced. These data demonstrate that a glycine residue at the -1 position of LAT Tyr132 functions as a kinetic bottleneck to restrain Tyr132 phosphorylation and signaling downstream of ITAM receptor engagement in the megakaryocyte lineage. These findings may have translational applications in the burgeoning field of in vitro platelet bioengineering.

Nutrient profile, protease and cellulase activities of protein extracted from black soldier fly (Hermetia illucens) larvae reared on various substrates

The Black Soldier Fly (BSF; Hermetia illucens) larvae are recognized for their ability to convert diverse organic materials into protein-rich biomass, depending on the substrate they consume. The composition of these substrates can significantly impact the nutrient profile and enzyme activities of the resulting maggot protein extract (MPE). Therefore, this exploratory research aimed to assess the nutrient content, protease, and cellulase activity of MPE obtained from BSF maggots reared on different substrates, with a specific focus on substrates A (comprising restaurant waste and rejected milk), B (layer manure), and C (kitchen waste). The results showed that maggot meal from layer manure had the highest protein content (45.36%) and the lowest fat content (18.44%). Amino acids in maggot meal contained high levels of glutamic acid, aspartic acid, alanine, valine, leucine, and isoleucine. Lauric acids were found in maggot meal from kitchen waste (33.79%), layer manure (32.18%), and restaurant waste and rejected milk (22.94%). Maggot meal from layer manure had the highest oleic acid content (15.13%). The protein concentration of MPE from various substrates ranged from 0.56 to 0.601 mg/ml (at 60% w/v ammonium sulfate saturation) and 0.555 to 0.609 mg/ml (at 70% ammonium sulfate saturation). The protease activity of MPE from layer manure substrates exhibited optimum activity and stability in neutral to alkaline pH, with activity levels of 0.748 U/mg at pH 7.0 and pH 11.0 (at 60% w/v ammonium sulfate saturation) and 0.774 units/mg at 70% w/v ammonium sulfate saturation. The highest cellulase activity was found in MPE from kitchen waste, which remained stable at pH 5.0-11.0. In general, maggots from different substrate sources exhibited distinct nutrient profiles and enzyme activities. Protein extract from maggots grown in layer manure showed the most suitable nutrient profile for use as an alternative source of protein feed and protease enzymes.

Phytochemical Analysis and Assessment of Antioxidant and Enzyme Inhibitory Activity of Alchemilla pseudocartalinica Juz.

This study aimed to evaluate and compare the antioxidant capacity and enzyme inhibitory activity of extracts, sub-extracts, and fractions prepared from the aerial parts and roots of A. pseudocartalinica. The phytochemical content of the active extracts was also analyzed. According to the results, ellagic acid (38.42 mg/g) was the major compound in the aerial part methanol extract and catechin (185.30 mg/g) in the root methanol extract. The DPPH inhibition activity of all fractions was monitored, with the most active one (Fr B) reaching an IC50 value of (4.92 ± 0.59 µg/mL). All the fractions prepared from the aerial parts' water sub-extract showed higher a-glucosidase inhibitory activity than the positive control acarbose. In the tyrosinase assay, Fr B (58.81 ± 7.50 µg/mL) exhibited the highest inhibitory actions among all fractions. The structure of the major substances of the most active fraction were elucidated as quercetin 7-O-β-glucopyranosyl-3-O-β-glucuronopyranoside- (1), and α-[(2-formyl-5-hydroxymethyl)pyrrol-1-yl]aspartic acid (2).

Nutritional and Functional Characteristics of Senescent Plantain Powder Mix

Post-harvest loss of plantain peeks at senescence. Drying senescent plantain enhances its culinary applications. This study aimed to determine the biochemical and functional properties of foam-mat dried senescent plantain samples, and their respective powdered mixes prepared for baking ofam (an Indigenous spicy cake). The nutritional benefits of foam-mat dried senescent plantain, with its high vitamin C and total carotenoid content, make it a valuable addition to dietary interventions. Foam-mat dried plantain samples and their respective powdered mixes were evaluated for their proximate composition, vitamin C, total carotenoids, amino acid contents, water and oil absorption capacities, and least gelation concentration using standard methods. The products were predominantly carbohydrates (73.3g - 80.4g/100g) with low moisture contents (9.19 - 20.68 g/100g). Vitamin C and total carotenoids ranged from 17.42 mg/100g to 33.99 mg/100g and 3.4 to 7.2 µg/g respectively. The samples had appreciable amounts of calcium (78.90 - 175.18 mg/100g), magnesium (112.13 - 113/79 mg/100g), potassium (95.76 - 77.09 mg/100g), iron (17.65 - 12.76 mg/100g) and zinc (10.94 - 15.82 mg/100 g). The most abundant amino acids were phenylalanine, histidine, methionine and aspartic acid. Sample SPPFSCF exhibited the best gelation capacity (22 g/100 mL). The water absorption capacities of the samples were influenced by the flour type used. However, the variations in the oil absorption capacities of the powdered mixes were statistically insignificant. EAPFRCF absorbed the least oil (0.84 g/g) while SPPFSCF absorbed the most (0.94 g/g). Foam-mat dried senescent plantain and their powdered mixes have the potential for utilization in nutritional interventions. Its low moisture content will support a longer shelf-life than the fresh overripe plantain.

Comparative analysis of the physical and chemical properties of dried products "KalmaKS" from the skin of the Commander and Pacific squid

The modern system of high-quality nutrition for the population includes the use of natural compounds from secondary products of animal origin. In the course of scientific substantiation of using secondary products from the processing of cephalopods, dried products from the skin of Pacific (Todarodes pacificus) and Commander squid (Berryteuthis magister) have been studied, their protein and amino acid composition and functional and technological characteristics have been analyzed. In samples from the skin of the Pacific squid, a high content of glutamic and aspartic acids (8–10 %) is noted; in samples from the skin of the Commander squid – glycine (20 %), proline (10 %) and arginine. High indicators of solubility, water-holding capacity and stability of foam structures are due to the significant content of type I destructured collagen (in a sample from the skin of Commander squid), and hydrophilic amino acids and type III collagen fragments (in a product made from Pacific squid skin). Infrared drying of products promotes denaturation and gelatinization of collagen in the skin of Commander squid, which is confirmed by the brighter color characteristics of the samples and high moisture-binding capacity when the temperature rises to 40 and 60 °C; this fact indicates an increase in the hydrophilic properties of the products of destruction of collagen fractions. Products made from skin, which is a secondary product of squid processing, have high potential for use in the food industry as water-retaining, fat-binding, and fat-emulsifying components.

New Supramolecular Hydrogels Based on Diastereomeric Dehydrotripeptide Mixtures for Potential Drug Delivery Applications.

Self-assembly of peptide building blocks offers unique opportunities for bottom-up preparation of exquisite nanostructures, nanoarchitectures, and nanostructured bulk materials, namely hydrogels. In this work we describe the synthesis, characterization, gelation, and rheological properties of new dehydrotripeptides, Cbz-L-Lys(Cbz)-L,D-Asp-∆Phe-OH and (2-Naph)-L-Lys(2-Naph)-L,D-Asp-∆Phe-OH, containing a N-terminal lysine residue Nα,ε-bis-capped with carboxybenzyl (Cbz) and 2-Naphthylacetyl (2-Naph) aromatic moieties, an aspartic acid residue (Asp), and a C-terminal dehydrophenylalanine (∆Phe) residue. The dehydrotripeptides were obtained as diastereomeric mixtures (L,L,Z and L,D,Z), presumably via aspartimide chemistry. The dehydrotripeptides afforded hydrogels at exceedingly low concentrations (0.1 and 0.04 wt%). The hydrogels revealed exceptional elasticity (G' = 5.44 × 104 and 3.43 × 106 Pa) and self-healing properties. STEM studies showed that the diastereomers of the Cbz-capped peptide undergo co-assembly, generating a fibrillar 3D network, while the diastereomers of the 2-Naph-capped dehydropeptide seem to undergo self-sorting, originating a fibril network with embedded spheroidal nanostructures. The 2-Naph-capped hydrogel displayed full fast recovery following breakup by a mechanical stimulus. Spheroidal nanostructures are absent in the recovered hydrogel, as seen by STEM, suggesting that the mechanical stimulus triggers rearrangement of the spheroidal nanostructures into fibers. Overall, this study demonstrates that diastereomeric mixtures of peptides can be efficacious gelators. Importantly, these results suggest that the structure (size, aromaticity) of the capping group can have a directing effect on the self-assembly (co-assembly vs. self-sorting) of diastereomers. The cytotoxicity of the newly synthesized gelators was evaluated using human keratinocytes (HaCaT cell line). The results indicated that the two gelators exhibited some cytotoxicity, having a small impact on cell viability. In sustained release experiments, the influence of the charge on model drug compounds was assessed in relation to their release rate from the hydrogel matrix. The hydrogels demonstrated sustained release for methyl orange (anionic), while methylene blue (cationic) was retained within the network.

Multi-omics profiling the dynamic variations of flavor and nutritional components during pearl gentian grouper soup processing

Flavor and nutritional value are essential components of fish soup, as highlighted by both producers and consumers. This study systematically examined the color, aroma, taste, and nutritional composition of pearl gentian grouper soup (PGGS) samples processed over varying durations, employing multi-omics technologies, including sensomics, volatilomics, lipidomics, and metabolomics. A comprehensive identification of 58 volatile aroma compounds, 407 lipids, 203 metabolites, and 47 taste components was achieved. The findings indicated that as processing time increased, the brightness of PGGS diminished, resulting in a thicker consistency. The aroma profile of PGGS was predominantly characterized by meaty and fatty notes, which were closely associated with carbonyl compounds (nonanal, dodecanal, (E)-2-octenal, and 2-undecanone) that developed due to glyceride oxidation during prolonged thermal processing. The predominant taste profile of PGGS was identified as umami, likely resulting from the synergistic effects of umami-enhancing amino acids (glutamic acid, aspartic acid) and 5ʹ-nucleotides (adenosine monophosphate, inosine monophosphate, guanosine monophosphate). Furthermore, PGGS may represent a significant source of taurine, with its taurine content accounting for over 60% of the total free amino acids (FAAs). Considering the variations in color, flavor, and nutritional content throughout the processing of PGGS, as well as the associated time costs, a processing duration of 2 h was optimal.

Extracellular polygalacturonase, β-1,4-glucanase and β-xylosidase in Geotrichum citri-aurrantii positively progressed the sour rot incidence in satsuma mandarin fruit

Gaining an understanding of the characteristics that contribute to the infectiousness of pathogens is essential for devising new strategies to control fungal infection. This study aims to identify and clarify the role of cell wall degrading enzymes (CWDEs) secreted by the Geotrichum citri-aurantii pathogen in the development of sour rot disease in Satsuma mandarin fruit. Results from in vivo experiments showed that CWDEs were secreted during arthrospore germination. Genomic sequencing and liquid chromatography-tandem mass spectrometry results unveiled the presence of polygalacturonase (PG), β-1,4-glucanase, α-glucosidase, xyloglucan:xyloglucosyl transferase, and β-xylosidase. Enzyme activity and gene expression analyses exposed the indispensable roles of PG and β-1,4-glucanase in the initial phase, and β-xylosidase during the acute phase of infection. After infection, we observed that the quantities of cellulose, pectin, and hemicellulose declined continuously, while the soluble pectin content rose steadily. Molecular docking analysis demonstrated that the diversity of CWDE binding to substrates complicated the G. citri-aurantii infection process. Furthermore, we determined the importance of asparagine and aspartic acid in PG-substrate interaction and glycine in β-xylosidase-ligand interaction. Taken together, our findings suggest that PG is a crucial target for blocking the development of sour rot in citrus fruit.