Aspartate Research Articles

Tetraalkynylporphyrin-mediated covalent assembly of gold nanoclusters for targeted tumor fluorescence imaging and enhanced photodynamic therapy.

A covalent assembly strategy was developed to construct agold nanocluster-based nano-assembly (AuNCNA) in a controllable manner, using Au8 nanocluster as node and 5,10,15,20-tetra(4-alkynylphenyl)porphine (TEPP) as ligand. Subsequently, the tripeptide arginine glycine aspartic acid (RGD) peptide is further modified via clicking reaction to build a multi-functional nanoplatform (AuNCNA@RGD) that can integrate the targeted fluorescence imaging and efficient photodynamic therapy (PDT). The strong interregulation of Au8 nanocluster and TEPP results in AuNCNA@RGD exhibiting three distinct advantages: (i) TEPP plays an important role in stabilizing the Au8 nanocluster and keeping the active site fixed within the framework, thereby enhancing stability of Au8 nanocluster; (ii) Au8 nanocluster possess adjustable energy level, which can accelerate the transfer of photogenerated charge and prevent the recombination of electrons and holes, thus improving thephotosensitivity of TEPP for PDT; (iii) AuNCNA exhibits bright fluorescence emission that facilitates RGD-assisted targeted tumor imaging. This work expands the construction method of AuNC assembly, and this assembly method is versatile and can flexibly transform different organic ligands to construct various AuNC-based functional nanomaterials.

Omics exploration of Tetraselmis chuii adaptations to diverse light regimes.

Microalgae are significantly influenced by light quality and quantity, whether in their natural habitats or under laboratory and industrial culture conditions. The present study examines the adaptive responses of the marine microalga Tetraselmis chuii to different light regimes, using a cost-effective filtering method and a multi-omics approach. Microalgal growth rates were negatively affected by all filtered light regimes. After six days of cultivation, growth rate for cultures exposed to blue and green filtered light was 67%, while for red filter was 83%, compared to control cultures. Transcriptomic analysis revealed that the usage of green filters resulted in upregulation of transcripts involved in ribosome biogenesis or coding for elongation factors, exemplified by a 2.3-fold increase of TEF3. On the other hand, a 2.7-fold downregulation was observed in photosynthesis-related petJ. Exposure to blue filtered light led to the upregulation of transcripts associated with pyruvate metabolism, while photosynthesis was negatively impacted. In contrast, application of red filter induced minor transcriptomic alterations. Regarding metabolomic analysis, sugars, amino acids, and organic acids exhibited significant changes under different light regimes. For instance, under blue filtered light sucrose accumulated over 6-fold, while aspartic acid content decreased by 4.3-fold. Lipidomics analysis showed significant accumulation of heptadecanoic and linoleic acids under green and red light filters. Together, our findings indicate that filter light can be used for targeted metabolic manipulation.

A Computational DFT Study of the Stereoinversion of Succinimide Residues Formed in Proteins and Peptides Catalyzed by a Hydrogen Phosphate Ion: An Unsymmetrical SE1 Mechanism

Succinimide residues formed spontaneously from aspartic acid (Asp) and asparagine (Asn) residues in proteins and peptides are stereochemically unstable, undergoing partial l-to-d stereoinversion, and this is responsible for the d-Asp and d-β-Asp residues found in long-lived proteins. These stereoinverted abnormal amino acid residues are believed to be related to aging and some age-related diseases such as cataracts. Although the succinimide stereoinversion is nonenzymatic, a catalyst is required for it to occur at physiological temperature. In this study, it was found by density functional theory (DFT) calculations that a hydrogen phosphate ion (HPO42−) can effectively catalyze the stereoinversion of the succinimide intermediate. The HPO42− ion abstracts a proton from the asymmetric carbon atom of the succinimide residue to form an enolate intermediate. Then, while the resultant dihydrogen phosphate ion (H2PO4−) remains bound to the enolate ion, a water molecule donates a proton to the enolate intermediate on the opposite side from the phosphate (which is the rate-determining step) to produce the inverted carbon atom. The calculated activation barrier (ca. 90 kJ mol−1) is consistent with a slow in vivo reaction. The present found mechanism can be termed the “unsymmetrical SE1” or “pseudo-SE2” mechanism.

Combined effect of molybdenum and nitrogen fertilization on nitrogen metabolism and amino acid content in tobacco leaves

IntroductionThis study investigated the combined effects of molybdenum (Mo) and nitrogen (N) fertilization on N metabolism and amino acid content in the leaves of flue-cured tobacco (Nicotiana tabacum L.) during its mature stage through a pot experiment.MethodsDifferent application levels of Mo (0, 0.15, 0.30 mg/kg soil) and N (0.06, 0.24, 0.42 g/kg soil) were set to observe and analyze changes in leaf quality, N, and amino acid content in the tobacco plants.ResultsThe results revealed that the N fertilizer application level exhibited a primary effect on regulating the total nitrogen, nitrate nitrogen, soluble protein, and amino acid nitrogen concentrations within tobacco leaves, while the effectiveness of Mo fertilization was influenced by the level of N applied. Specifically, under the conditions of 0.24 g/kg soil N and 0.30 mg/kg soil Mo application, the N content, N accumulation, and dry matter mass of the tobacco plants increased significantly by 110%, 204%, and 48%, respectively. Concurrently, nitrate reductase activity increased by 107-fold, and the nitrate nitrogen content was relatively low, contributing to enhanced tobacco yield and safety. Moreover, this treatment led to a notable (170%) increase in free amino acid nitrogen content, with minimal impact on total amino acids and soluble proteins. Notably, it effectively increased the content of free amino acids beneficial to the sensory quality of tobacco (such as histidine, arginine, aspartic acid, isoleucine, and glutamic acid) without reducing the total amino acid content, while simultaneously reducing other amino acids that might affect quality. Therefore, the combined application of 0.30 mg/kg soil Mo and 0.24 g/kg soil N specifically optimized the amino acid composition in tobacco leaves, positively impacting overall quality and market competitiveness.DiscussionThis study provides a theoretical basis for the rational application of Mo fertilizer in Mo-deficient areas to improve the yield and quality of flue-cured tobacco.

Case Report: Hemoglobin Hasharon with Concurrent Alpha Thalassemia in a Patient with Maple Syrup Urine Disease

Abstract Hemoglobin Hasharon (Hb Hasharon) is an unstable hemoglobin variant stemming from a mutation in the alpha globin gene. This mutation involves the replacement of aspartic acid with histidine at position 47 of the alpha globin chain. Initially identified in 1967 in Israel, Hb Hasharon has since been sporadically reported in various populations, including in Italy, Greece, Germany, and among Latin Americans of Mediterranean descent. Only three English articles have reported several cases of the combined alpha thalassemia deletion and Hasharon mutation, all between 1978-1980. Notably, there has been no prior report of Hb Hasharon with concurrent alpha thalassemia in patients with maple syrup urine disease (MSUD). We hereby present the first case of Hb Hasharon with alpha thalassemia in a patient diagnosed with MSUD. This patient, a 16-month-old female, received a prenatal diagnosis of MSUD through amniocentesis, confirming homozygosity for a known pathogenic variant in DBT (c.75_76delAT, p.C26wfsX2). Prompt initiation of formula feeding has effectively controlled her MSUD. The patient was referred for further evaluation due to hemoglobin newborn screen showing hemoglobin A, Hb F and “variant hemoglobin”. Her parents denied any family history of hemoglobinopathy. Her complete blood count was predominantly normal except for mild microcytosis, with a mean corpuscular volume of 69.1 fl (normal range 70.0-86.0 fl). The patient didn’t exhibit neonatal jaundice or any other signs or symptoms of hemolysis. The reticulocyte count was also within normal limits. The hemoglobin electrophoresis results revealed a complex pattern, with 28.8% of an unknown hemoglobin between zone 4 and 5 on capillary zone electrophoresis (CZE) as well as a possible A2 variant in zone 1. High-performance liquid chromatography (HPLC) indicated a 29.1% peak at a retention time of 4.72 minutes, along with several smaller peaks, that were indicative of the degradation of the unstable unknown hemoglobin. Although the zones and retention time aligned with Hb Hasharon, the percentage differed from the expected range of 19-20% in CZE and 18-21% in HPLC for this variant, prompting the team to order alpha and beta globin sequencing tests. Beta globin gene complete sequencing yielded negative results, while the sequencing of alpha globin gene revealed that the patient carries one copy of the -alpha3.7 alpha-globin deletion and one copy of the c.142G>C (p.Asp48His) variant in the alpha2-globin (HBA2) gene, resulting in an -alpha/alpha2alpha1 genotype with Hb Hasharon. While Hb Hasharon is generally not clinically significant, its co-occurrence with alpha-thalassemia can lead to hemolytic anemia. In our patient, clinic and chemical parameters were predominantly within normal ranges, except for mild microcytosis. The potential interaction between MSUD and Hb Hasharon with concurrent alpha thalassemia remains unknown. Continued patient monitoring will enable us to evaluate whether these conditions may influence each other’s clinical and biochemical profiles.

Green Light Drives Embryonic Photosynthesis and Protein Accumulation in Cotyledons of Developing Pea (Pisum sativum L.) Seeds

Photosynthesis is a vital process for seed productivity. It occurs in the leaves and provides developing seeds with the necessary nutrients. Moreover, many crops require photochemical reactions inside the seeds for proper development. The present study aimed to investigate Pisum sativum L. seeds at the middle stage of maturation, which is characterized by the active synthesis of nutrient reserves. Embryonic photosynthesis represents a crucial process to produce cells’ NADP(H) and ATP, which are necessary to convert sucrose into reserve biopolymers. However, it remains unclear how the pea embryo, covered by a coat and pericarp, receives sufficient light to provide energy for photochemical reactions. Recent studies have demonstrated that the photosynthetically active radiation reaching the developing pea embryo has a high proportion of green light. In addition, green light can be utilized in foliar photosynthesis by plants cultivated in shaded conditions. Here, we addressed the role of green light in seed development. Pea plants were cultivated under red and blue (RB) LEDs or red, green, and blue (RGB) LEDs. A Chl a fluorescence transient based on OJIP kinetics was detected at the periphery of the cotyledons isolated from developing seeds. Our findings showed that the addition of green light resulted in an increase in photochemical activity. Furthermore, the mature seeds that developed in the RGB module had a significantly higher weight and more storage proteins. Using a metabolomics approach, we also detected significant differences in the levels of organic acids, carbohydrates, nucleotide monophosphates, and nitrogenous substances between the RB and RGB conditions. Under RGB light, the cotyledons contained more ornithine, tryptophan, arginine, and aspartic acid. These changes indicate an impact of green light on the ornithine–urea cycle and polyamine biosynthesis. These results allow for a deeper understanding of the photochemical processes in embryos of developing seeds grown under a low light intensity. The photosynthetic system in the embryo cell adapts to the shade conditions by using green light.

EVALUATION OF THE EFFICACY OF ASPARAGINASE ADDED TO CHEMOTHERAPEUTIC DRUG REGIMEN IN ACUTE LYMPHOBLASTIC LEUKEMIA BY MINIMAL RESIDUAL DISEASE MEASUREMENT

B-ALL is the most common subtype of childhood Acute Lymphoblastic Leukemia (ALL), affecting approximately 85% of children worldwide. Minimal Residual Disease (MRD) monitoring during treatment of ALL is important for the prognosis of the disease. MRD monitoring, which enables early detection of relapse, determination of risk percentage and understanding the effectiveness of treatment, can be performed with multiple methods such as flow cytometry, qRT-PCR and NGS. Asparaginase is an enzyme that has been used in the treatment of ALL since the 1960s, converting asparagine to ammonia and aspartic acid, lowering serum asparagine levels and causing the death of malignant cells. In this study, we investigated the effect of asparaginase added to the ALL IC BFM 2009 treatment protocol in 62 B-ALL patients aged 0-18 years with MRD monitoring by flow cytometry. In our study, Escherichia Coli (E.Coli.) asparaginase was used primarily and PEG-asparaginase was used after allergy development. The effect of asparaginase on treatment was evaluated by evaluating asparagine concentration and asparaginase activity measured at TP1 (4th week after induction treatment) together with MRD levels. As a result of the study, it was observed that the added asparaginase positively affected the treatment and increased the negativity in MRD levels.

Targeted metabolomic profiling of acute ST-segment elevation myocardial infarction

Myocardial infarction is a major cause of morbidity and mortality worldwide. Metabolomic investigations may be useful for understanding the pathogenesis of ST-segment elevation myocardial infarction (STEMI). STEMI patients were comprehensively examined via targeted metabolomic profiling, machine learning and weighted correlation network analysis. A total of 195 subjects, including 68 STEMI patients, 84 patients with stable angina pectoris (SAP) and 43 non-CVD patients, were enrolled in the study. Metabolomic profiling involving the quantitative analysis of 87 endogenous metabolites in plasma was conducted. This study is the first to perform targeted metabolomic profiling in patients with STEMI. We identified 36 significantly altered metabolites in STEMI patients. Increased levels of four amino acids, eight acylcarnitines, six metabolites of the NO–urea cycle and neurotransmitters, and three intermediates of tryptophan metabolism were detected. The following metabolites exhibited decreased levels: six amino acids, three acylcarnitines, three components of the NO–urea cycle and neurotransmitters, and three intermediates of tryptophan metabolism. We found that the significant changes in tryptophan metabolism observed in STEMI patients—the increase in anthranilic acid and tryptophol and decrease in xanthurenic acid and 3-OH-kynurenine—may play important roles in STEMI pathogenesis. On the basis of the differences in the constructed weighted correlation networks, new significant metabolite ratios were identified. Among the 22 significantly altered metabolite ratios identified, 13 were between STEMI patients and non-CVD patients, and 17 were between STEMI patients and SAP patients. Seven of these ratios were common to both comparisons (STEMI patients vs. non-CVD patients and STEMI patients vs. SAP patients). Additionally, two ratios were consistently observed among the STEMI, SAP and non-CVD groups (anthranilic acid: aspartic acid and GSG (glutamine: serine + glycine)). These findings provide new insight into the diagnosis and pathogenesis of STEMI.

Mechanistic Insights of Amino Acid Binding to Hydroxyapatite: Molecular Dynamics Charts Future Directions in Biomaterial Design.

Extensive efforts have been made to improve the understanding of hard tissue regeneration, essential for advancing medical applications like bone graft materials. However, the mechanisms of bone biomineralization, particularly the regulation of hydroxyapatite growth by proteins/peptides, remain debated. Small biomolecules such as amino acids are ideal for studying these mechanisms due to their simplicity and relevance as protein/peptide building blocks. This study investigates the binding affinity of four amino acids including glycine (Gly), proline (Pro), lysine (Lys), and aspartic acid (Asp) to the hydroxyapatite (HAP) (100) surface through molecular dynamics simulations. Our findings reveal that aspartic acid exhibits the most energetically favorable binding affinity, attributed to its additional carboxylate group (-COO-), which facilitates stronger interactions with Ca2+ ions on the HAP surface compared to other amino acids with single carboxylate groups. This highlights the critical role of specific functional groups in modulating binding strength, emphasizing that the presence of multiple binding sites in amino acids enhances binding stability. Interestingly, the study also uncovers the significance of water-mediated interactions, as the compact water layer above the HAP surface acts as a barrier, complicating direct binding and underscoring the need to consider solvation effects in simulations. Glycine, due to its small size, demonstrates a unique ability to penetrate this tightly bound water monolayer, suggesting that molecular size influences binding dynamics. These simulations offer detailed insights into the atomic-level interactions, providing a deeper understanding of binding affinity and stability. These insights are pertinent for designing peptides or proteins with enhanced interactions with biomaterials, particularly in mimicking natural bone-binding processes.

PAM-relaxed and temperature-tolerant CRISPR-Mb3Cas12a single transcript unit systems for efficient singular and multiplexed genome editing in rice, maize, and tomato.

Class 2 Type V-A CRISPR-Cas (Cas12a) nucleases are powerful genome editing tools, particularly effective in A/T-rich genomic regions, complementing the widely used CRISPR-Cas9 in plants. To enhance the utility of Cas12a, we investigate three Cas12a orthologs-Mb3Cas12a, PrCas12a, and HkCas12a-in plants. Protospacer adjacent motif (PAM) requirements, editing efficiencies, and editing profiles are compared in rice. Among these orthologs, Mb3Cas12a exhibits high editing efficiency at target sites with a simpler, relaxed TTV PAM which is less restrictive than the canonical TTTV PAM of LbCas12a and AsCas12a. To optimize Mb3Cas12a, we develop an efficient single transcription unit (STU) system by refining the linker between Mb3Cas12a and CRISPR RNA (crRNA), nuclear localization signal (NLS), and direct repeat (DR). This optimized system enables precise genome editing in rice, particularly for fine-tuning target gene expression by editing promoter regions. Further, we introduced Arginine (R) substitutions at Aspartic acid (D) 172, Asparagine (N) 573, and Lysine (K) 579 of Mb3Cas12a, creating two temperature-tolerant variants: Mb3Cas12a-R (D172R) and Mb3Cas12a-RRR (D172R/N573R/K579R). These variants demonstrate significantly improved editing efficiency at lower temperatures (22 °C and 28 °C) in rice cells, with Mb3Cas12a-RRR showing the best performance. We extend this approach by developing efficient Mb3Cas12a-RRR STU systems in maize and tomato, achieving biallelic mutants targeting single or multiple genes in T0 lines cultivated at 28 °C and 25 °C, respectively. This study significantly expands Cas12a's targeting capabilities in plant genome editing, providing valuable tools for future research and practical applications.

Enhancing De Novo Protein Sequencing through the C-Terminal Labeling Strategy: Resolving Isobaric Ambiguities by Electron-Transfer/Higher Energy Collision Dissociation (EThcD).

De novo protein sequencing via a bottom-up approach requires various proteases to produce overlapping peptides. However, peptides generated by proteases other than trypsin, LysC, and ArgC often yield C-terminal fragments with suboptimal ionization in positive mode mass spectrometry (MS). This study introduces a novel peptide labeling strategy that involves modifying peptides at the C-terminal and at the carboxyl groups of Aspartic and Glutamic acid with arginine methyl ester (R-met) to improve peptide fragmentation and resolve isobaric ambiguities encountered during sequencing. An amidation reaction is used with coupling reagents to conjugate R-met to the peptide's C-terminal end, introducing a functional group that enhances the detectability of C-terminal peptide fragment ions by mass spectrometry. Subsequently, selecting a charge state of +2 or higher can facilitate optimal fragmentation of the derivatized peptides using electron-transfer/higher energy collision dissociation (EThcD), thereby generating essential w-ions to resolve common isobaric ambiguities. Demonstrating this strategy across diverse protein types, including albumin and antibodies and using different proteases for digestion, highlights the unique characteristics of combining the proposed amidation reaction with the specific proteases tested.

Synthesis and Anti-Liver Fibrosis Research of Aspartic Acid Derivatives

Liver fibrosis plays an important role in the progression of liver disease, but there is a severe shortage of direct and efficacious pharmaceutical clinical interventions. Literature research indicates that aspartic acid exhibits hepatoprotective properties. In this paper, 32 target compounds were designed and synthesized utilizing aspartic acid as the lead compound, of which 22 were new compounds not reported in the literature. These compounds were screened for their inhibitory effects on the COL1A1 promoter to assess in vitro anti-liver fibrosis activity and summarized structure–activity relationships. Four compounds exhibited superior potency with inhibition rates ranging from 66.72% to 97.44%, substantially higher than EGCG (36.46 ± 4.64%) and L-Asp (11.33 ± 0.35%). In an LPS-induced inflammation model of LX-2 cells, both 41 and 8a could inhibit the activation of LX-2 cells, reducing the expression of COL1A1, fibronectin, and α-SMA. Upon further investigation, 41 and 8a ameliorated liver fibrosis by inhibiting the IKKβ-NF-κB signaling pathway to alleviate inflammatory response. Overall, the study evaluated the anti-liver fibrosis effects of aspartic acid derivatives, identified the potency of 41, and conducted a preliminary exploration of mechanisms, laying the foundation for the discovery of novel anti-liver fibrosis agents.

Copper-amino acid/Carboxymethyl starch composite for controllable releasing of povidone-iodine

Povidone-iodine is identified as one of the widely applicable antiseptic reagents for treatment of skin infection and wound healing. Controllable releasing of povidone-iodine is extensively required for healing of chronic wounds. The release of povidone-iodine was systematically studied from the composites based on carboxymethyl starch (CMS). Currently, different ratios from copper precursor and L-aspartic acid (L-AA) were interacted with CMS to obtain Cu-L-AA@CMS composites. Increment the percentage of L-AA was reflected in clustering of dense masses from the desirable composite with highly crystalline/stable structural network. Regardless to pH conditions, Cu-L-AA(30%)@CMS composite showed the highest efficiency for controllable release of povidone-iodine, whereas, the release percentages were estimated to be 58%, 32% and 18% at pH 5, 7 and 9, respectively. The kinetic results revealed the impossibility of povidone-iodine releasing via diffusion/erosion for further support of the hypothesis of releasing via swelling process. Moreover, the release of povidone-iodine using column technique showed that the lowest release was estimated at using high rate of 6 mL/min. Besides the biocompatibility and biodegradability of the prepared Cu-L-AA@CMS composites, it showed the superiority for controllable release of povidone-iodine antiseptic reagent to regulate its beneficial effect in curing of the skin.

Metabolomic analysis reveals potential role of immunometabolism dysregulation in recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) affects women's reproductive health seriously, with immune dysfunction playing a key role in its cause, yet the exact mechanisms remain elusive. We aim to investigate potential mechanisms and identify biomarkers linked to RPL. Immune cytokine testing and metabolomic profiling were conducted on the serum of 34 RPL patients and 30 healthy individuals. The metabolic pathways of the differential metabolites were analyzed, and specific metabolites were validated through targeted profiling. Potential biomarkers were identified, and the relationships between immune cytokines and differential metabolites were explored. In the RPL group, serum interleukin-6 and interleukin-10 levels were significantly higher, while interleukin-2 and interferon-γ were significantly lower. A total of 296 differential metabolites were detected by untargeted metabolomic profiling between the RPL and control groups, with most linked to amino acid metabolism. Targeted metabolomic profiling of amino acid metabolism revealed upregulation of indole-3-acetic acid, tyrosine, glycine, isoleucine, tryptophan, lysine, aspartic acid, arginine, leucine, threonine, glutamic acid, cystine, and phenylpyruvic acid (PPA) in the RPL group. Moreover, PPA and 5-hydroxy-L-tryptophan showed great potential in predicting RPL in a diagnostic model. Cystine and tyrosine were associated with immune cytokines in correlation analysis. The study highlights the role of amino acid metabolism in RPL pathogenesis, suggesting that PPA and 5-HTP may be potential predictive indicators, while cystine and tyrosine may potentially regulate immune responses related to RPL. Further investigation into the molecular mechanisms underlying these findings could potentially result in the creation of novel diagnostic and therapeutic approaches for RPL.

Dynamic changes in aroma compounds and precursor substances during rice cooking

Cooking is a key process in forming cooked rice flavor, and more data on aroma compounds should be needed during rice cooking. This paper tracked dynamic changes in aroma compounds, sugars, amino acids, and fatty acids during cooking. After soaking, the content of glucose, fructose, oleic acid, and linoleic acid increased. In the hydrothermal cooking stage, glucose, aspartic acid, glutamic acid, and alanine increased significantly (p < 0.05), while fructose, oleic acid, and linoleic acid first increased and then decreased. In raw rice and soaked rice, alkanes and alkenes were the main volatile compounds, and the content of hydrocarbon compounds decreased in the hydrothermal cooking stage, and many aldehydes, alcohols, ketones, and furan compounds were generated. A total of 28 aroma compounds were sniffed by GC-O-MS, and 13 aroma compounds with OAV >1 were screened out. These results showed that raw rice and soaked rice had similar aroma characteristics and aroma precursor substances that mainly accumulated in the SO10 or ST10 stage, and hydrothermal cooking was the key process of rice aroma formation.

Self-aggregation effect of the ternary system “Alga EPS-DOM-HMs” and the characterization of the self-adaptation metabolic response of microalgae

Heavy metals (HMs) present in the natural aquatic environment can form a ternary aggregate of “EPS-DOM-HMs” with the prevalent microalgae extracellular polymers substances (EPS) and macromolecular dissolved organic matters (DOMs), which show special molecular structure and biological interaction. This study reveals the formation of “EPS-TA-HMs” and the mechanism of their physiological and metabolic effects on Raphidocelis subcapitata. Results indicate that TA-Cr(III) can bind to EPS to form ternary aggregates with substances coexisting large and small hydrodynamic diameters and that the interactions are dominated by hydrophobic interactions of the protein binding to the pyrrole ring of the polyphenol and hydrogen bonding interactions formed by OC–(N R O). The protein structure of EPS has the largest proportion of proline, glycine, aspartic acid, and tryptophan. These interactions promoted the secretion of EPS components and reduced the growth inhibition of Raphidocelis subcapitata by 45.9 % compared with Cr(III) exposure. TEM analysis combined with EDS analysis indicated that Cr(III) was taken intracellularly and TA-Cr(III) was not. In addition, metabolomics analyses revealed that microalgae initiate adaptive mechanisms via the activation of a two-component system (i.e., maintenance of high metabolic activity). This study underscored the morphology of HMs in real aquatic environments and the mechanisms of metabolic effects on aquatic organisms.

Phosphorylation of Ser711 residue in the hypervariable region of zoonotic genotype 3 hepatitis E virus is important for virus replication.

Hepatitis E virus (HEV) is distinct from other hepatotropic viruses because it is zoonotic. HEV-1 and HEV-2 exclusively infect humans, whereas HEV-3 and HEV-4 are zoonotic. However, the viral and/or host factors responsible for cross-species HEV transmission remain elusive. The hypervariable region (HVR) in HEV is extremely heterogenetic and is implicated in HEV adaptation. Here, we investigated the potential role of Serine phosphorylation in the HVR in HEV replication. We first analyzed HVR sequences across different HEV genotypes and identified a unique region at the N-terminus of the HVR, which is variable in the human-exclusive HEV genotypes but relatively conserved in zoonotic HEV genotypes. Using predictive tools, we identified four potential phosphorylation sites that are highly conserved in zoonotic HEV-3 and HEV-4 genomes but absent in human-exclusive HEV-1 strains. To explore the functional significance of these putative phosphorylation sites, we introduced mutations into the HEV-3 infectious clone and indicator replicon, replacing each Serine residue individually with alanine or aspartic acid, and assessed the impact of these substitutions on HEV-3 replication. We found that the phospho-blatant S711A mutant significantly reduced virus replication, whereas the phospho-mimetic S711D mutant modestly reduced virus replication. Conversely, mutations in the other three Serine residues did not significantly affect HEV-3 replication. Furthermore, we demonstrated that Ser711 phosphorylation did not alter host cell tropism of zoonotic HEV-3. In conclusion, our results showed that potential phosphorylation of the Ser711 residue significantly affects HEV-3 replication in vitro, providing new insights into the potential mechanisms of zoonotic HEV transmission.IMPORTANCEHEV is an important zoonotic pathogen, causing both acute and chronic hepatitis E and extrahepatic manifestation of diseases, such as neurological sequelae. The zoonotic HEV-3 is linked to chronic infection and neurological diseases. The specific viral and/or host factors facilitating cross-species HEV infection are unknown. The intrinsically disordered HVR in ORF1 is crucial for viral fitness and adaptation, both in vitro and in vivo. We hypothesized that phosphorylation of Serine residues in the HVR of zoonotic HEV by unknown host cellular kinases is associated with cross-species HEV transmission. In this study, we identified a conserved region within the HVR of zoonotic HEV strains but absent in the human-exclusive HEV-1 and HEV-2. We elucidated the important role of phosphorylation at the Ser711 residue in zoonotic HEV-3 replication, without altering the host cell tropism. These findings contribute to our understanding the mechanisms of cross-species HEV transmission.

Citric Acid by-Product Fermentation by Bacillus subtilis I9: A Promising Path to Sustainable Animal Feed

Citric acid by-products in animal feed pose a sustainability challenge. Bacillus species are commonly used for fermenting and improving the nutritional quality of feedstuffs or by-products. An experiment was conducted to enhance the nutritional value of citric acid by-products through fermentation with Bacillus subtilis I9 for animal feed. The experiment was carried out in 500 mL Erlenmeyer flasks with 50 g of substrate and 200 mL of sterile water. Groups were either uninoculated or inoculated with B. subtilis I9 at 107 CFU/mL. Incubation occurred at 37 °C with automatic shaking at 150 rpm under aerobic conditions for 0, 24, 48, 72, and 96 h. Inoculation with B. subtilis I9 significantly increased Bacillus density to 9.3 log CFU/mL at 24 h (p &lt; 0.05). CMCase activity gradually increased, reaching a maximum of 9.77 U/mL at 72 h. After 96 h of fermentation with inoculated B. subtilis I9, the citric acid by-product exhibited a significant decrease (p &lt; 0.05) in crude fiber by 10.86%, hemicellulose by 20.23%, and cellulose by 5.98%, but an increase in crude protein by 21.89%. Gross energy decreased by 4% after inoculation with B. subtilis in comparison to the uninoculated control (p &lt; 0.05). Additionally, the non-starch polysaccharide (NSP) degradation due to inoculation with B. subtilis I9 significantly reduced (p &lt; 0.05) NSP by 24.37%, while galactose, glucose, and uronic acid decreased by 22.53%, 32.21%, and 18.11%, respectively. Amino acid profile content increased significantly by more than 12% (p &lt; 0.05), including indispensable amino acids such as histidine, isoleucine, lysine, methionine, phenylalanine, tryptophan, and valine and dispensable amino acids like alanine, aspartic acid, glutamic acid, glutamine, glycine, proline, and tyrosine. Furthermore, citric acid by-products inoculated with B. subtilis I9 exhibited changes in the cell wall structure under scanning electron microscopy, including fragmentation and cracking. These results suggest that fermenting citric acid by-products with B. subtilis I9 effectively reduces dietary fiber content and improves the nutritional characteristics of citric acid by-products for use in animal feed.

Defect-Engineered MOF-801/Sodium Alginate Aerogel Beads for Boosting Adsorption of Pb(II).

Metal-organic frameworks (MOFs) are attractive adsorbents for heavy metal capture due to their superior stability, easy modification, and adjustable pore size. However, their inherent microporous structure poses challenges in achieving a higher adsorption capacity. Defect engineering is considered a simple method to create hierarchical MOFs with larger pores. Here, we employed l-aspartic acid as a mixed linker to bind Zr4+ clusters in competition with fumaric acid of MOF-801 to create defects, and the pore size was increased from 4.66 to 15.65 nm. Mercaptosuccinic acid was subsequently used as a postexchange ligand to graft the resultant MOF-801 by acid-ammonia condensation to further expand the pore size to 22.73 nm. Notably, the -NH2, -COOH, and -SH groups contributed by these two ligands increased the adsorption sites for Pb(II). The obtained defective MOF-801 with larger pores was thereafter loaded onto sodium alginate to form aerogel beads as adsorbents, and an adsorption capacity of 375.48 mg/g for Pb(II) was achieved, which is ∼51 times that of pristine MOF-801. The aerogel beads also exhibited outstanding reusability with a removal efficiency of ∼90.23% after 5 cycles of use. The adsorption mechanism of Pb(II) included ion-exchange interaction, as well as chelation interactions of Pb-O, Pb-NH2, and Pb-S. The versatile combination of defect engineering and composite beads provides novel inspirations for MOF modification for boosting heavy metal adsorption.

Kinetic studies of AST isoenzymes I,II,III,IV partially purified from patient,s urine with chroinc renal failure

In this research, the kinetic studies of four isoenzymes of Asprtate aminotransferase, which partially purified from the urine of chronic renal failure patients were carried out .The four isoenzymes were obeyed Michaelis-Menton's equation and the optimum concentration of their substrate (Aspartic acid) was (166.5x10-3) mole/liter,and their Km values were determined. Four isoenzymesI,II,III,IV have shown an optimum pH at 7.4.The four isoenzymes obeyed Arrhenius equation up to 37º C and their Ea and Q10 constants were determined .