Aspartate Research Articles

A Clinical Study of Urine Amino Acids in Children with Autism Spectrum Disorder.

We designed a case-control study that consisted of 75 boys and girls, aged between 2 and 12 years. For amino acid profile, we used urine samples that were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Descriptive analysis showed higher values for glutamine, hydroxyproline, tyrosine, aspartic acid, and tryptophan and lower values for serine in the autism group than in the control group. Also, we found that boys with autism had higher values than the boys in the control group for serine, threonine, and aspartic acid. For girls from both groups, we did not find statistically significant values. In terms of age groups, we found significantly higher values for histidine, threonine, valine, methionine, aspartic acid, glutamic acid, alpha amino-adipic acid, sarcosine, alanine, and beta-alanine and significantly lower values for proline for both the autism and control groups under 5 years. The findings of this study support the assumption that amino acids may have a role in the expression of ASD.

Improving aromatic higher alcohol acetates in wines by co-fermentation of Pichia kluyveri and Saccharomyces cerevisiae: growth interaction and amino acid competition.

Higher alcohol acetates (HAAs) are potent aroma-active esters that impart desirable fruity and floral aromas. However, the conversion of higher alcohol precursors into HAAs is extremely low in winemaking. To investigate the underlying yeast-yeast interaction on targeted improvement of aromatic HAAs, we evaluated fermentation activity, cell viability, amino acid consumption and HAA production when Pichia kluyveri and Saccharomyces cerevisiae were inoculated concurrently or sequentially. Pichia kluyveri PK-21 possessed the ability to survive and increased HAA level up to 5.2-fold in mixed fermentation. Such an increment may benefit from the efficient conversion of higher alcohol precursors into HAAs (>27-fold higher than S. cerevisiae). During mixed fermentation, the two yeasts exhibited crucial interactions regarding cell growth and amino acid competition. Saccharomyces cerevisiae dominated over the co-inoculated P. kluyveri by efficient uptake of amino acids and biomass production. However, this dominance decreased in sequential fermentation, where P. kluyveri growth increased due to the consumption of preferred amino acids prior to S. cerevisiae. Pearson correlation analysis indicated that phenylalanine and aspartic acid may act as positive amino acids in boosting P. kluyveri growth and HAA production. Laboratory-scale winemaking validated the fermentation performance of P. kluyveri in sequential inoculum, resulting in a balanced aroma profile with enhanced floral and tropical fruity characteristics in the final wines. This study proposes a microbial, non-genetically engineered approach for targeted increase of HAA production in winemaking and the findings provide new insights into yeast-yeast interactions. © 2024 Society of Chemical Industry.

Inhibitory Effect and Mechanism upon Glucose-Insulin-Potassium Administration on Postpartum Mice with Uterine Cramping Pain.

This study aimed to explore the effect of glucose-insulin-potassium (GIK) on postpartum uterine cramping pain(UCP) in mice and the possible underlying mechanisms. Thirty full-term pregnancy C57BL/6 mice, within 6h after spontaneous labor, the mice were randomly assigned into the following three groups: the control group (group C), the oxytocin group (group O), and the GIK plus oxytocin group (group G). Group G and group O were administered GIK and normal saline, respectively, and 10min later, oxytocin was injected intraperitoneally; group C received normal saline twice. The pain scores of the mice were assessed after establishment of the postpartum UCP model. The differential expressions of energy metabolism and oxidized lipid metabolites in the uterus were analyzed. The behavioral scores in group G were significantly lower than those in group O (P < 0.05).When compared to group O, group G showed a significant increase in ATP levels (P = 0.046), and group G exhibited elevated levels of amino acids, including L-glutamine, L-aspartic acid, and ornithine. Additionally, phosphate compounds (2-phosphoglyceric acid and 3-phosphoglyceric acid) showed elevated levels. When compared to group O, group G exhibited a decrease in 19R-hydroxy PGF2α, an increase in 9,10-EpOME and 12,13-EpOME, and a decrease in trans-EKODE-E-Ib. Additionally, group G showed an elevation in 16,17-EpDPE and 8-HDoHE. This study confirms the analgesic effect of GIK during postpartum oxytocin infusion. Metabolomics and glycolysis product analysis suggest that GIK's alleviation of UCP is associated with its enhancement of glycolysis and the influence of phenylalanine synthesis, aspartate metabolism, and arginine synthesis pathways. Additionally, the effects of GIK appears to be linked to its influence on the linoleic acid metabolic pathway.

Iron-sulfur protein odyssey: exploring their cluster functional versatility and challenging identification.

Iron-sulfur (Fe-S) clusters are an essential and ubiquitous class of protein-bound prosthetic centers that are involved in a broad range of biological processes (e.g. respiration, photosynthesis, DNA replication and repair and gene regulation) performing a wide range of functions including electron transfer, enzyme catalysis, and sensing. In a general manner, Fe-S clusters can gain or lose electrons through redox reactions, and are highly sensitive to oxidation, notably by small molecules such as oxygen and nitric oxide. The [2Fe-2S] and [4Fe-4S] clusters, the most common Fe-S cofactors, are typically coordinated by four amino acid side chains from the protein, usually cysteine thiolates, but other residues (e.g. histidine, aspartic acid) can also be found. While diversity in cluster coordination ensures the functional variety of the Fe-S clusters, the lack of conserved motifs makes new Fe-S protein identification challenging especially when the Fe-S cluster is also shared between two proteins as observed in several dimeric transcriptional regulators and in the mitoribosome. Thanks to the recent development of in cellulo, in vitro, and in silico approaches, new Fe-S proteins are still regularly identified, highlighting the functional diversity of this class of proteins. In this review, we will present three main functions of the Fe-S clusters and explain the difficulties encountered to identify Fe-S proteins and methods that have been employed to overcome these issues.

Polybrominated diphenyl ethers (PBDEs) decreased the protein quality of rice grains by disturbing amino acid metabolism

Polybrominated diphenyl ethers (PBDEs) in soils posed potential risks to crop growth and food safety due to their prevalence and persistence. PBDEs were capable of being absorbed and accumulated into crops, impacting their growth, whereas the interference on metabolic components and nutritional composition deserves further elucidation. This study integrated a combined non-targeted and targeted metabolomics method to explore the influences of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47), 2,2′,4,4′,5-pentabromodiphenyl ether (BDE-99) and decabromodiphenyl ether (BDE-209) on the metabolic responses of rice (Oryza sativa). Metabolic pathways, which were associated with sugars, organic acids, and amino acids, were significantly disturbed under PBDE stresses. Particularly, 75% of the marked altered pathways belonged to amino acid metabolism, with alanine/aspartate/glutamate metabolism being commonly enhanced. The degradation of aspartic acid promoted the formation of downstream amino acids, among which the levels of lysine, methionine, isoleucine, and asparagine were increased by 1.31–3.15 folds compared to the control. Thus, the antioxidant capacity in rice plants was enhanced, particularly through the significant promotion of ascorbic acid-glutathione (AsA-GSH) cycle in rice leaves. The amino acids were promoted to resist reactive oxygen species (ROS) efficiently, thus were deficient for nutrient storage. When exposed to 4 μmol/kg PBDEs, the contents of amino acids and proteins in grains decreased by 9.1–32.1% and 8.6–34.8%, respectively. In particular, glutelin level was decreased by 5.6–41.2%, resulting in a decline in nutritional quality. This study demonstrated that PBDEs deteriorated the protein nutrition in rice grains by affecting amino acid metabolism, providing a new perspective for evaluating the ecological risks of PBDEs and securing agricultural products.

Effects of Tannin Supplementation in Diet on the Resistance to Ammonia Stress of Pacific White Shrimp Litopenaeus vannamei

Tannin (TA), as a natural phenolic compound with strong antioxidant activity, has been used as a feed additive for various animals. In this study, we fed a diet containing 800 mg/kg of tannin on Litopenaeus vannamei for 56 days and then subjected to acute ammonia stress for 48 hr to investigate the effect of dietary tannin on the ammonia stress response of L. vannamei through transcriptomic and metabolomic analysis. The transcriptome analysis indicated that ammonia stress-induced differential expression of 4,185 genes, while tannin-fed shrimp only had 964 differentially expressed genes. Compared with the TA_0 group, 59 pathways were significantly altered, and the pathways of “starch and sucrose metabolism,” “retinol metabolism,” “arachidonic acid metabolism,” “lysosome,” and “amino sugar and nucleotide sugar metabolism” were highly enriched in the TS_0 group. Compared with the TS_0 group, six pathways were significantly altered, and the pathways of “dilated cardiomyopathy,” “complement and coagulation cascades,” “cardiac muscle contraction,” “fructose and mannose metabolism,” “cGMP-PKG signaling pathway,” and “beta-alanine metabolism” were significantly enriched in the TS_800 group. Metabolomic analysis showed that a total of 107 differential metabolites (DMs) were identified in the TS_0 vs. TA_0 group, while 75 DMs were identified in the TS_800 vs. TS_0 group. Based on KEGG annotation, it was found that a large amount of DM was significantly enriched in amino acid metabolism pathways in the TS_0 group, including “arginine and proline metabolism,” “alanine, aspartic acid, and glutamic acid metabolism,” “β-Alanine metabolism and tyrosine metabolism” indicated that tannins affect the metabolism of amino acids. The integration of DEGs and DMs indicates that dietary tannins highly alter the digestion and absorption functions of proteins, as well as the biosynthesis and metabolism of amino acids. This study provides new insights into the adaptation of Pacific white shrimp to ammonia stress and the addition of tannins to feed to enhance immune function.

Simulation and experimental study on amphiphilic modified graphene oxide for EOR

The application of nanosheet in enhanced oil recovery (EOR) offers a practical approach to resolving some surface-related problems. In this study, theoretical calculation and experiment were combined to study the interfacial behavior and mechanism of amphiphilic modified graphene oxide. Octadecyl amine and aspartic acid were successfully grafted onto graphene oxide nanosheets by starch template method. The stability of the modified structure was verified by IR, XRD and SEM. The change of microstructure in molecular simulation can enhance the understanding of the structure of amphiphilic modified nanosheets under SEM. The contact angle experiment directly shows its amphiphilicity, which shows that the contact angle of hydrophilic surface is 34.6° and that of hydrophobic surface is 103.5°. The interfacial elasticity experiment shows that the interfacial film formed by synthetic GOTA has certain elasticity. When the concentration increases, the interfacial film formed in the adsorption process can effectively separate the oil and water phases. Based on the interfacial tension value, the ability of graphene oxide and modified graphene oxide with different concentrations to reduce the interfacial tension between distilled water and diesel oil was investigated successively. The mechanism of GOTA action was explained from the aspects of molecular structure and energy by molecular simulation. The results show that the interfacial tension fluctuates around 16 mN/m when the GOTA concentration is 0.005%, and the average interfacial tension is 17.48 mN/m when the GOTA concentration (molecular number percentage) is 0.004% in the simulation process, which is highly consistent. Further studies have shown that the interface formation energy of the system is significantly reduced after the addition of zwitterionic surfactants, and the interfacial tension can be reduced to 11.95 mN/m. With the help of molecular simulation, the adsorption mechanism of GOTA on the interface is explained from the aspects of microstructure change, interaction energy, cohesion energy, interface density and conformation. The adjustment of these interactions will directly affect the oil-water interface morphology and interfacial tension.

Regulation of electroacupuncture on non-canonical pathway of hepatocellular pyroptosis in rats with nonalcoholic fatty liver disease

To observe the effect and mechanism of electroacupuncture (EA) on non-canonical pathway of hepatocellular pyroptosis in nonalcoholic fatty liver disease (NAFLD). Sixty male SD rats were randomly divided into a normal diet group (n=15) and a high fat modeling group (n=45). The rats in the high fat modeling group were fed with customized high fat diet for 8 weeks to establish NAFLD model. Thirty successfully modeled rats were selected and randomly divided into a model group (n=10), an EA group (n=10) and a non-acupoint with shallow needling group (n=10), and 10 rats were randomly selected from the normal diet group as the control group additionally. In the EA group, EA was applied at bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), with disperse-dense wave, in frequency of 4 Hz/20 Hz and in intensity of 3 mA. In the non-acupoint with shallow needling group, shallow needling was delivered at points 5 mm from bilateral "Fenglong" (ST 40) and "Ganshu" (BL 18), the EA stimulation parameters were same as the EA group. The intervention was given once a day, 20 min a time, 5 days a week for 4 weeks in the two groups. After intervention, the liver morphology was observed by oil red "O" staining, the serum levels of lipopolysaccharide (LPS), interleukin (IL)-1β, IL-18 and tumor necrosis factor-α (TNF-α) were detected by ELISA, the protein expression of gasdermin D (GSDMD), GSDMD-N, cysteine aspartic acid specific protease-11 (Caspase-11), IL-1β, IL-18 and TNF-α in liver tissue were detected by Western blot, the mRNA expression of GSDMD, Caspase-11, IL-1β, IL-18 and TNF-α in liver tissue was detected by real-time PCR in rats of each group. In the model group, vacuoles in different size were found in the hepatocellular cytoplasm, and the fat droplets were in schistose accumulation. Compared with the model group, the hepatocellular fat droplets and the degree of hepatic steatosis were reduced in the EA group and the non-acupoint with shallow needling group. Compared with the control group, the serum levels of LPS, IL-1β, IL-18 and TNF-α were increased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1β, IL-18, TNF-α as well as the protein expression of GSDMD-N in the liver tissue were increased (P<0.01) in the model group. Compared with the model group, the serum levels of LPS, IL-1β, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, IL-1β, IL-18 and TNF-α in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of Caspase-11 in the liver tissue were decreased (P<0.01) in the EA group and the non-acupoint with shallow needling group. Compared with the model group, the protein expression of Caspase-11 in the liver tissue was decreased (P<0.01) in the EA group. Compared with the non-acupoint with shallow needling group, the serum levels of LPS, IL-1β, IL-18 and TNF-α were decreased (P<0.01), the protein and mRNA expression of GSDMD, Caspase-11, IL-1β and IL-18 in the liver tissue were decreased (P<0.01), the protein expression of GSDMD-N and the mRNA expression of TNF-α in the liver tissue were decreased (P<0.01) in the EA group. EA can inhibit hepatocellular pyroptosis in NAFLD rats, and its mechanism may be related to reducing the serum level of LPS, and down-regulating the expression of the non-canonical pathway related factors i.e. GSDMD, GSDMD-N, Caspase-11, IL-1β, IL-18 and TNF-α.

Key umami taste contributors in Longjing green tea uncovered by integrated means of sensory quantitative descriptive analysis, metabolomics, quantification analysis and taste addition experiments

Umami taste is a key criteria of green tea quality evaluation. The aim of this study was to comprehensively explore the key umami taste contributors in Longjing tea. The taste and molecular profiles of 36 Longjing green tea infusions were characterized by sensory quantitative descriptive analysis and LC-MS based metabolomics, respectively. By uni−/multi-variate statistical analysis, 84 differential compounds were screened among tea infusions with varied umami perceptions. Among them, 17 substances were identified as candidate umami-enhancing compounds, which showed significant positive correlations with umami intensities. Their natural concentrations were accurately quantified, and their umami taste-modifying effects were further investigated by taste addition into glutamic acid solution. Glutamic acid, aspartic acid, glutamine, theanine, phenylalanine, histidine, theogallin, galloylglucose, 1,2,6-trigalloylglucose significantly enhanced the umami taste. This study uncovered for the first time of some bitter amino acids and galloylglucose homologous series as important umami-enhancers, which provided a novel perspective into the tea taste.

Oceanobacillus picturae alleviates cadmium stress and promotes growth in soybean seedlings

Cadmium (Cd) is a heavy metal that significantly impacts human health and the environment. Microorganisms play a crucial role in reducing heavy metal stress in plants; however, the mechanisms by which microorganisms enhance plant tolerance to Cd stress and the interplay between plants and microorganisms under such stress remain unclear. In this study, Oceanobacillus picturae (O. picturae) was isolated for interaction with soybean seedlings under Cd stress. Results indicated that Cd treatment alone markedly inhibited soybean seedling growth. Conversely, inoculation with O. picturae significantly improved growth indices such as plant height, root length, and fresh weight, while also promoting recovery in soil physiological indicators and pH. Metabolomic and transcriptomic analyses identified 157 genes related to aspartic acid, cysteine, and flavonoid biosynthesis pathways. Sixty-three microbial species were significantly associated with metabolites in these pathways, including pathogenic, adversity-resistant, and bioconductive bacteria. This research experimentally demonstrates, for the first time, the growth-promoting effect of the O. picturae strain on soybean seedlings under non-stress conditions. It also highlights its role in enhancing root growth and reducing Cd accumulation in the roots under Cd stress. Additionally, through the utilization of untargeted metabolomics, metagenomics, and transcriptomics for a multi-omics analysis, we investigated the impact of O. picturae on the soil microbiome and its correlation with differential gene expression in plants. This innovative approach unveils the molecular mechanisms underlying O. picturae's promotion of root growth and adaptation to Cd stress.

The Changes of Amino-Acid Metabolism between Wheat and Rice during Early Growth under Flooding Stress.

Floods induce hypoxic stress and reduce wheat growth. On the other hand, rice is a semi-aquatic plant and usually grows even when partially submerged. To clarify the dynamic differences in the cellular mechanism between rice and wheat under flooding stress, morphological and biochemical analyses were performed. Although the growth of wheat in the early stage was significantly suppressed due to flooding stress, rice was hardly affected. Amino-acid analysis revealed significant changes in amino acids involved in the gamma-aminobutyric acid (GABA) shunt and anaerobic/aerobic metabolism. Flood stress significantly increased the contents of GABA and glutamate in wheat compared with rice, though the abundances of glutamate decarboxylase and succinyl semialdehyde dehydrogenase did not change. The abundance of alcohol dehydrogenase and pyruvate carboxylase increased in wheat and rice, respectively. The contents of aspartic acid and pyruvic acid increased in rice root but remained unchanged in wheat; however, the abundance of aspartate aminotransferase increased in wheat root. These results suggest that flooding stress significantly inhibits wheat growth through upregulating amino-acid metabolism and increasing the alcohol-fermentation system compared to rice. When plant growth is inhibited by flooding stress and the aerobic-metabolic system is activated, GABA content increases.

Efficacy and Safety of Asparagusic Acid against Echinococcus multilocularis In Vitro and in a Murine Infection Model.

Alveolar echinococcosis (AE) stands as a perilous zoonotic affliction caused by the larvae of Echinococcus multilocularis. There is an imperative need to explore novel therapeutic agents or lead compounds for the treatment of AE. Asparagusic acid, characterized by its low toxicity and possessing antimicrobial, antioxidant, and anti-parasitic attributes, emerges as a promising candidate. The aim of this study was to investigate the in vivo and in vitro efficacy of asparagusic acid against E. multilocularis. Morphological observations, scanning electron microscopy, ROS assays, mitochondrial membrane potential assays, and Western blot were used to evaluate the in vitro effects of asparagusic acid on protoscoleces. The effects of asparagusic acid on vesicles were assessed via PGI release, γ-GGT release, and transmission electron microscopy observations. CellTiter-Glo assays, Caspase3 activity assays, flow cytometry, and Western blot were used for an evaluation of the effect of asparaginic acid on the proliferation and apoptosis of germinal cells. The in vivo efficacy of asparagusic acid was evaluated in a murine AE model. Asparagusic acid exhibited a pronounced killing effect on the protoscoleces post-treatment. Following an intervention with asparagusic acid, there was an increase in ROS levels and a decline in mitochondrial membrane potential in the protoscolex. Moreover, asparagusic acid treatment resulted in the upregulation of PGI and γ-GGT release in metacestode vesicles, concomitant with the inhibition of germinal cell viability. Furthermore, asparagusic acid led to an enhanced relative expression of Caspase3 in the culture supernatant of both the protoscoleces and germinal cells, accompanied by an increase in the proportion of apoptotic germinal cells. Notably, asparagusic acid induced an augmentation in Bax and Caspase3 protein expression while reducing Bcl2 protein expression in both the protoscoleces and germinal cells. In vitro cytotoxicity assessments demonstrated the low toxicity of asparagusic acid towards normal human hepatocytes and HFF cells. Additionally, in vivo experiments revealed that asparagusic acid administration at doses of 10 mg/kg and 40 mg/kg significantly reduced metacestode wet weight. A histopathological analysis displayed the disruption of the germinal layer structure within lesions post-asparagusic acid treatment, alongside the preservation of laminated layer structures. Transmission electron microscopy further revealed mitochondrial swelling and heightened cell necrosis subsequent to the asparagusic acid treatment. Furthermore, asparagusic acid promoted Caspase3 and Bax protein expression while decreasing Bcl2 protein expression in perilesional tissues. Subsequently, it inhibited the expression of Ki67, MMP2, and MMP9 proteins in the perilesional tissues and curbed the activation of the PI3K/Akt signaling pathway within the lesion-host microenvironmental tissues. Asparagusic acid demonstrated a pronounced killing effect on E. multilocularis, suggesting its potential as a promising therapeutic agent for the management of AE.

Amino acids as stabilizers for lysozyme during the spray-drying process and storage

Amino acids (AAs) have been used as excipients in protein formulations both in solid and liquid state products due to their stabilizing effect. However, the mechanisms by which they can stabilize a protein have not been fully elucidated yet. The purpose of this study was to investigate the effect of AAs with distinct physicochemical properties on the stability of a model protein (lysozyme, LZM) during the spray-drying process and subsequent storage. Molecular descriptor based multivariate data analysis was used to select distinct AAs from the group of 20 natural AAs. Then, LZM and the five selected AAs (1:1 wt ratio) were spray-dried (SD). The solid form, residual moisture content (RMC), hygroscopicity, morphology, secondary/tertiary structure and enzymatic activity of LZM were evaluated before and after storage under 40 °C/75 % RH for 30 days. Arginine (Arg), leucine (Leu), glycine (Gly), tryptophan (Trp), aspartic acid (Asp) were selected because of their distinct properties by using principal component analysis (PCA). The SD LZM powders containing Arg, Trp, or Asp were amorphous, while SD LZM powders containing Leu or Gly were crystalline. Recrystallization of Arg, Trp, Asp and polymorph transition of Gly were observed after the storage under accelerated conditions. The morphologies of the SD particles vary upon the different AAs formulated with LZM, implying different drying kinetics of the five model systems. A tertiary structural change of LZM was observed in the SD powder containing Arg, while a decrease in the enzymatic activity of LZM was observed in the powders containing Arg or Asp after the storage. This can be attributed to the extremely basic and acidic conditions that Arg and Asp create, respectively. This study suggests that when AAs are used as stabilizers instead of traditional disaccharides, not only do classic vitrification theory and water replacement theory play a role, but the microenvironmental pH conditions created by basic or acidic AAs in the starting solution or during the storage of solid matter are also crucial for the stability of SD protein products.

Novel insights into whey protein peptide-iron chelating agents: Structural characterization, in vitro stability and functional properties

In this study, whey protein iron chelating peptides were obtained by trypsin hydrolysis of whey protein, and the whey protein peptides-iron chelate (WPP-Fe) was prepared. The structural characterization of the whey protein peptides-iron chelate were determined, comprising ultraviolet-visible spectrum, fluorescence spectrum, infrared spectrum, secondary structure content, x-ray diffraction, particle size, zeta potential, microstructure and surface elemental compositions. The results showed that under the conditions of pH 5.0, the mass ratio of whey protein peptides to FeSO4 was 3:1, chelated at 35 °C for 30 min, iron chelating and chelating yield was 85.92% and 77.38% respectively. The content of aspartic acid and glutamic acid were positively correlated with iron chelating ability. The whey protein peptides-iron chelate had good pH, salt concentration and gastrointestinal digestive stability compared to FeCl2, ferrous gluconate and ferrous glycine. Besides, the DPPH eliminate ability and bacteriostatic properties of the whey protein peptides-iron chelate (WPP-Fe) were better than the whey protein peptide (WPP). These findings can be used as a theoretical basis for the development of new peptide iron supplements.

BrBCAT1 mutation resulted in deficiency of epicuticular wax crystal in Chinese cabbage.

BrBCAT1 encoding a branched-chain amino acid aminotransferase was responsible for the glossy trait, which was verified by allelic mutants in Chinese cabbage. The glossy characteristic, thanks to the epicuticular wax crystal deficiency, is an excellent commodity character for leafy vegetables. Herein, two allelic glossy green mutants, wdm11 and wdm12, were isolated from an ethyl methane sulfonate (EMS)-mutagenized population of Chinese cabbage, and the mutant phenotype was recessive inherited. Cryo-SEM detected that epicuticular wax crystal in the mutant leaves was virtually absent. MutMap and Kompetitive allele-specific PCR analyses demonstrated that BraA06g006950.3C (BrBCAT1), homologous to AtBCAT1, encoding a branched-chain amino acid aminotransferase was the candidate gene. A SNP (G to A) on the fourth exon of BrBCAT1 in wdm11 caused the 233rd amino acid to change from glycine (G) to aspartic acid (D). A SNP (G to A) on the second exon of BrBCAT1 in wdm12 led to the 112th amino acid change from glycine (G) to arginine (R). Both of the allelic mutants had genetic structural variation in the candidate gene, which indicated that the mutant phenotype was triggered by the BrBCAT1 mutation. The expression levels of BrBCAT1 and genes related to fatty acid chain extension were decreased significantly in the mutant compared to the wild-type, which might result in epicuticular wax crystal deficiency in the mutants. Our findings proved that the mutation of BrBCAT1 induced the glossy phenotype and provided a valuable gene resource for commodity character improvement in Chinese cabbage.

Diorganotin (IV) amino acid complexes as potential anticancer agents. Synthesis, structural characterization, and in vitro assays

Nine new organotin (IV) derivatives from L-amino acids (l-lysine, L-ornithine, L-glutamic acid, and L-aspartic acid) were synthesized by one-pot ultrasound-assisted methodology. All compounds were characterized by ATR-FTIR (Attenuated Total Reflectance-Fourier Transform Infrared), LRMS (Low-Resolution Mass Spectrometry), and solution NMR (1H, 13C, 119Sn Nuclear Magnetic Resonance) spectroscopies. Complexes Bu2Sn(Lys) (1), Ph2Sn(Lys) (2), Bu2Sn(Orn) (3), and Ph2Sn (Glu-OMe) (6a) were crystallized, and the structures were established by single-crystal X-ray diffraction analysis. Diffraction results evidenced that complexes 1 to 3 were five-coordinated mononuclear species while the phenyl substituted derivative Ph2Sn (Glu-OMe) (6a) forms a polymeric network via Sn–O–Sn bridging whereby the tin atom is six-coordinated. In turn, 119Sn NMR results revealed that all tin complexes exist as mononuclear penta-coordinated species in solution. The tin derivatives were screened for ADME (Adsorption, Distribution, Metabolism, and Excretion) properties via the freely available tools SWISS ADME, and the results were analyzed hereafter. The antiproliferative activity of the complexes was tested against three human cancer cell lines: colorectal adenocarcinoma HT-29, breast adenocarcinoma MDA-MB-231, and chondrosarcoma SW-1353 using a non-tumoral cell line of human osteoblast as control, demonstrating selective inhibitory activities against cancer cells. Hence, these compounds could be a promising alternative to classical chemotherapy agents.

Comparative Probiogenomics Analysis of Limosilactobacillus fermentum 3872.

Limosilactobacillus fermentum is an important member of the lactic acid bacteria group and holds immense potential for probiotic properties in human health and relevant industries. In this study, a comparative probiogenomic approach was applied to analyze the genome sequence of L. fermentum 3872, which was extracted from a commercially available yogurt sample, along with 20 different publicly available strains. Results indicate that the genome size of the characterized L. fermentum 3892 strain is 2,057,839bp, with a single- and circular-type chromosome possessing a G + C content of 51.69%. The genome of L. fermentum 3892 strain comprises a total of 2120 open reading frames (ORFs), two genes encoding rRNAs, and 53 genes encoding tRNAs. Upon comparative probiogenomic analysis, two plasmid sequences were detected among the study strains, including one for the L. fermentum 3872 genome, which was found between position 1,288,203 and 1,289,237 with an identity of 80.98. The whole-genome alignment revealed 2223 identical sites and a pairwise identity of 98.9%, indicating a significant difference of 1.1% among genome strains. Comparison of amino acid encoding genes among strains included in this study suggests that the strain 3872 exhibited the highest degree of amino acids present, including glutamine, glutamate, aspartate, asparagine, lysine, threonine, methionine, and cysteine. The comparative antibiotic resistome profiling revealed that strain 3872 exhibited a high resistant capacity only to ciprofloxacin antibiotics as compared to other strains. This study provides a genomic-based evaluation approach for comparative probiotic strain analysis in commercial foods and their significance to human health.

Metabolomics revealed that toxic cyanobacteria stress reduced the flavor quality of Bellamya aeruginosa

The environmental impact of increased eutrophication and frequent cyanobacterial blooms on the growth and reproduction of aquatic organisms has become increasingly prominent in recent years. Bellamya aeruginosa is a nutrient-rich aquatic snail consumed by humans, and environmental changes may decrease its meat quality. However, the specific characteristics of muscle metabolism and flavor quality in freshwater snails and their response patterns to bloom-forming cyanobacterial stress have not been reported. Therefore, in this study, alterations in metabolites in the snail muscle after following feeding on toxic Microcystis aeruginosa were investigated using untargeted metabolomics. A total of 1,128 metabolites were identified, and the metabolic pathways of unsaturated fatty acid biosynthesis and purine, glutathione, and glycerophospholipid metabolism in snails fed toxic cyanobacteria differed from those in snails fed Chlorella vulgaris. Quantitative analysis showed increased levels of bitter-free amino acids, such as tyrosine, phenylalanine, and histidine, after consuming toxic cyanobacteria for 42 d, whereas a relative decrease was observed in the levels of umami- and sweet-free amino acids, such as glutamic acid, aspartic acid, serine, threonine, and glicine. The muscles of snails fed toxic cyanobacteria exhibited higher hypoxanthine and hypoxanthine nucleoside and lower adenosine triphosphate, adenine nucleotide, adenine nucleoside diphosphate, and hypoxanthine nucleotide contents than those of snails fed C. vulgaris. Furthermore, increased metabolites, such as stearic acid, palmitic acid, and cytidine diphosphate choline, and decreased metabolites, such as docosapentaenoic acid, docosahexaenoic acid, adrenoic acid, and L-glutamic acid, reflect the harmful effects of toxic cyanobacteria on the nutritional value and flesh quality of B. aeruginosa. This study comprehensively evaluated the effects of cyanobacterial blooms on freshwater gastropods, providing an important theoretical basis for the quality, safety, and sustainable development of snails as food and related processing industries.

Changes in amino acids, catechins and alkaloids during the storage of oolong tea and their relationship with antibacterial effect

The storage process has a significant impact on tea quality. Few is known about effect of storage on quality of oolong tea. This study aimed to assess the effect of different storage times on the key chemical components of oolong tea by measuring changes in catechin, free amino acid, and alkaloid content. Variation in the main substances was determined by principal component analysis and heat map analysis. The results revealed notable effects of the storage process on the levels of theanine, epigallocatechin gallate (EGCG), and glutamine. These findings suggest that these compounds could serve as indicators for monitoring changes in oolong tea quality during storage. Additionally, the study observed an increase in the antibacterial ability of tea over time. Correlation analysis indicated that the antibacterial ability against Micrococcus tetragenus and Escherichia coli was influenced by metabolites such as aspartic acid, threonine, serine, gamma-aminobutyric acid, ornithine, alanine, arginine, and EGCG. Overall, this study presents an approach for identifying key metabolites to monitor tea quality effectively with relatively limited data.

Engineered Phenylalanine Ammonia-Lyases for the Enantioselective Synthesis of Aspartic Acid Derivatives.

Biocatalytic hydroamination of alkenes is an efficient and selective method to synthesize natural and unnatural amino acids. Phenylalanine ammonia-lyases (PALs) have been previously engineered to access a range of substituted phenylalanines and heteroarylalanines, but their substrate scope remains limited, typically including only arylacrylic acids. Moreover, the enantioselectivity in the hydroamination of electron-deficient substrates is often poor. Here, we report the structure-based engineering of PAL from Planctomyces brasiliensis (PbPAL), enabling preparative-scale enantioselective hydroaminations of previously inaccessible yet synthetically useful substrates, such as amide- and ester-containing fumaric acid derivatives. Through the elucidation of cryo-electron microscopy (cryo-EM) PbPAL structure and screening of the structure-based mutagenesis library, we identified the key active site residue L205 as pivotal for dramatically enhancing the enantioselectivity of hydroamination reactions involving electron-deficient substrates. Our engineered PALs demonstrated exclusive α-regioselectivity, high enantioselectivity, and broad substrate scope. The potential utility of the developed biocatalysts was further demonstrated by a preparative-scale hydroamination yielding tert-butyl protected l-aspartic acid, widely used as intermediate in peptide solid-phase synthesis.