Search

Introduction: Salinity negatively affects maize productivity. However, calcium lignosulfonate (CLS) could improve soil properties and maize productivity. Methods: In this study, we evaluated the effects of CLS application on soil chemical properties, plant physiology and grain quality of maize under salinity stress. Thus, this experiment was conducted using three CLS application rates, CLS0, CLS5, and CLS10, corresponding to 0%, 5%, and 10% of soil mass, for three irrigation water salinity (WS) levels WS0.5, WS2.5, and WS5.5 corresponding to 0.5 and 2.5 and 5.5 dS/m, respectively. Results and discussion: Results show that the WS0.5 × CLS10 combination increased potassium (K 0.167 g/kg), and calcium (Ca, 0.39 g/kg) values while reducing the sodium (Na, 0.23 g/kg) content in soil. However, the treatment WS5.5 × CLS0 decreased K (0.120 g/kg), and Ca (0.15 g/kg) values while increasing Na (0.75 g/kg) content in soil. The root activity was larger in WS0.5 × CLS10 than in WS5.5 × CLS0, as the former combination enlarged K and Ca contents in the root while the latter decreased their values. The leaf glutamine synthetase (953.9 µmol/(g.h)) and nitrate reductase (40.39 µg/(g.h)) were higher in WS0.5 × CLS10 than in WS5.5 × CLS0 at 573.4 µmol/(g.h) and 20.76 µg/(g.h), leading to the improvement in cell progression cycle, as revealed by lower malonaldehyde level (6.57 µmol/g). The K and Ca contents in the leaf (881, 278 mg/plant), stem (1314, 731 mg/plant), and grains (1330, 1117 mg/plant) were greater in WS0.5 × CLS10 than in WS5.5 × CLS0 at (146, 21 mg/plant), (201, 159 mg/plant) and (206, 157 mg/plant), respectively. Therefore, the maize was more resistance to salt stress under the CLS10 level, as a 7.34% decline in yield was noticed when salinity surpassed the threshold value (5.96 dS/m). The protein (13.6 %) and starch (89.2 %) contents were greater in WS0.5 × CLS10 than in WS5.5 × CLS0 (6.1 %) and (67.0 %), respectively. This study reveals that CLS addition can alleviate the adverse impacts of salinity on soil quality and maize productivity. Thus, CLS application could be used as an effective soil amendment when irrigating with saline water for sustainable maize production. [ABSTRACT FROM AUTHOR]

The retina is light-sensitive neuronal tissue in the back of the eye. The phospholipid composition of the retina is unique and highly enriched in polyunsaturated fatty acids, including docosahexaenoic fatty acid (DHA). While it is generally accepted that a high DHA content is important for vision, surprisingly little is known about the mechanisms of DHA enrichment in the retina. Furthermore, the biological processes controlled by DHA in the eye remain poorly defined as well. Here, we combined genetic manipulations with lipidomic analysis in mice to demonstrate that acyl-CoA synthetase 6 (Acsl6) serves as a regulator of the unique composition of retinal membranes. Inactivation of Acsl6 reduced the levels of DHA-containing phospholipids, led to progressive loss of light-sensitive rod photoreceptor neurons, attenuated the light responses of these cells, and evoked distinct transcriptional response in the retina involving the Srebf1/2 (sterol regulatory element binding transcription factors 1/2) pathway. This study identifies one of the major enzymes responsible for DHA enrichment in the retinal membranes and introduces a model allowing an evaluation of rod functioning and pathology caused by impaired DHA incorporation/retention in the retina. Acyl-CoA synthetase 6 (Acsl6)-facilitated enrichment of docosahexaenoic acid (DHA) in the retina is essential for rod photoreceptor function, viability and control of basal activity of the Srebf1/2 pathway. [ABSTRACT FROM AUTHOR]

Leaves experience near-constant light fluctuations daily. Past studies have identified many limiting factors of slow photosynthetic induction when leaves transition from low light to high light. However, the contribution of photorespiration in influencing photosynthesis during transient light conditions is largely unknown. This study employs dynamic measurements of gas exchange and metabolic responses to examine the contribution of photorespiration in constraining net rates of carbon assimilation during light induction. This work indicates that photorespiratory glycine accumulation during the early light induction contributes 5–7% to the additional carbon fixed relative to the low light conditions. Mutants with large glycine pools under photorespiratory conditions (5-formyl THF cycloligase and hydroxypyruvate reductase 1) showed a transient spike in net CO2 assimilation during light induction, with glycine buildup accounting for 22–36% of the extra carbon assimilated. Interestingly, levels of many C3 cycle intermediates remained relatively constant in both mutants and wild-type throughout the light induction period where glycine accumulated, indicating that recycling of carbon into the C3 cycle via photorespiration is not needed to maintain C3 cycle activity under transient conditions. Furthermore, our data show that oxygen transient experiments can be used as a proxy to identify the photorespiratory component of light-induced photosynthetic changes. [ABSTRACT FROM AUTHOR]

[Objective] Glutamine synthetase (GS) is a key enzyme in the GS-GOGAT cycle of nitrogen metabolism. This work is aimed to investigate the family members of GS in soybean and the response to external stress. [Method] Based on bioinformatics methods, we comprehensively identified GS genes in soybean (Glycine max), clarified the location and structure of soybean GmGSs genes, the physicochemical properties of proteins, and the tissue expression patterns, and also studied the responses to abiotic stresses. [Result] The total of eight GS genes were identified from the soybean, located on eight chromosomes, corresponding to coding amino acid sequences with lengths ranging from 356 to 432 aa. Among the ten conserved motifs, all eight GmGS contained nine conserved motifs, and GmGS7 and GmGS8 had one more motif 10 conserved motif than other members. Analysis of promoter's cis-acting elements showed that the promoters of GmGSs contained abundant light-responsive elements, hormone-responsive elements, and adversity stress-responsive elements. Transcriptome data analysis showed that GmGSs genes were expressed in all tissues, with GmGS3 and GmGS4 having higher expression in all tissues. Fluorescence quantitative qPCR results revealed that GmGS4, GmGS5, and GmGS7 of soybean GS family responded most significantly to the late stage of low concentration ammonium treatment after different concentrations of ammonium chloride. And after high salt stress treatment, the expression of GmGS5 decreased in the root, stem and leaf tissues; while the expression of GmGS7 increased in root and stem tissues. [Conclusion] There are eight GS members in soybean, of which GmGS7 is involved in response to both ammonium chloride treatment and salt stress. [ABSTRACT FROM AUTHOR]

Achieving the green development of agriculture requires the reduction of chemical nitrogen (N) fertilizer input. Previous studies have confirmed that returning green manure to the field is an effective measure to improve crop yields while substituting partial chemical N fertilizer. However, it remains unclear how to further intensify the substituting function of green manure and elucidate its underlying agronomic mechanism. In a split-plot field experiment in spring wheat, different green manures returned to the field under reduced chemical N supply was established in an oasis area since 2018, in order to investigate the effect of green manure and reduced N on grain yield, N uptake, N use efficiency (NUE), N nutrition index, soil organic matter, and soil N of wheat in 2020-2022. Our results showed that mixed sown common vetch and hairy vetch can substitute 40% of chemical N fertilizer without reducing grain yield or N accumulation. Noteworthily, mixed sown common vetch and hairy vetch under reduced N by 20% showed the highest N agronomy efficiency and recovery efficiency, which were 92.0% and 46.0% higher than fallow after wheat harvest and conventional N application rate, respectively. The increase in NUE of wheat was mainly attributed to mixed sown common vetch and hairy vetch, which increased N transportation quantity and transportation rate at pre-anthesis, enhanced N harvest index, optimized N nutrition index, and increased activities of nitrate reductase and glutamine synthetase of leaf, respectively. Meanwhile, mixed sown common vetch and hairy vetch under reduced N by 20% improved soil organic matter and N contents. Therefore, mixed sown common vetch and hairy vetch can substitute 40% of chemical N fertilizer while maintaining grain yield and N accumulation, and it combined with reduced chemical N by 20% or 40% improved NUE of wheat via enhancing N supply and uptake. [ABSTRACT FROM AUTHOR]

The amide proteogenic amino acids, asparagine and glutamine, are two of the twenty amino acids used in translation by all known life. The aminoacyl‐tRNA synthetases for asparagine and glutamine, asparaginyl‐tRNA synthetase and glutaminyl tRNA synthetase, evolved after the split in the last universal common ancestor of modern organisms. Before that split, life used two‐step indirect pathways to synthesize asparagine and glutamine on their cognate tRNAs to form the aminoacyl‐tRNA used in translation. These two‐step pathways were retained throughout much of the bacterial and archaeal domains of life and eukaryotic organelles. The indirect routes use non‐discriminating aminoacyl‐tRNA synthetases (non‐discriminating aspartyl‐tRNA synthetase and non‐discriminating glutamyl‐tRNA synthetase) to misaminoacylate the tRNA. The misaminoacylated tRNA formed is then transamidated into the amide aminoacyl‐tRNA used in protein synthesis by tRNA‐dependent amidotransferases (GatCAB and GatDE). The enzymes and tRNAs involved assemble into complexes known as transamidosomes to help maintain translational fidelity. These pathways have evolved to meet the varied cellular needs across a diverse set of organisms, leading to significant variation. In certain bacteria, the indirect pathways may provide a means to adapt to cellular stress by reducing the fidelity of protein synthesis. The retention of these indirect pathways versus acquisition of asparaginyl‐tRNA synthetase and glutaminyl tRNA synthetase in lineages likely involves a complex interplay of the competing uses of glutamine and asparagine beyond translation, energetic costs, co‐evolution between enzymes and tRNA, and involvement in stress response that await further investigation. [ABSTRACT FROM AUTHOR]

Photorespiration, caused by oxygenation of the enzyme Rubisco, is considered a wasteful process, because it reduces photosynthetic carbon gain, but it also supplies amino acids and is involved in amelioration of stress. Here, we show that a sudden increase in photorespiratory activity not only reduced carbon acquisition and production of sugars and starch, but also affected diurnal dynamics of amino acids not obviously involved in the process. Flux calculations based on diurnal metabolite profiles suggest that export of proline from leaves increases, while aspartate family members accumulate. An immense increase is observed for turnover in the cyclic reaction of glutamine synthetase/glutamine-oxoglutarate aminotransferase (GS/GOGAT), probably because of increased production of ammonium in photorespiration. The hpr1-1 mutant, defective in peroxisomal hydroxypyruvate reductase, shows substantial alterations in flux, leading to a shift from the oxoglutarate to the aspartate family of amino acids. This is coupled to a massive export of asparagine, which may serve in exchange for serine between shoot and root. [ABSTRACT FROM AUTHOR]

The AMP-forming acetyl-CoA synthetase is regulated by lysine acetylation both in bacteria and eukaryotes. However, the underlying mechanism is poorly understood. The Bacillus subtilis acetyltransferase AcuA and the AMP-forming acetyl-CoA synthetase AcsA form an AcuA•AcsA complex, dissociating upon lysine acetylation of AcsA by AcuA. Crystal structures of AcsA from Chloroflexota bacterium in the apo form and in complex with acetyl-adenosine-5′-monophosphate (acetyl-AMP) support the flexible C-terminal domain adopting different conformations. AlphaFold2 predictions suggest binding of AcuA stabilizes AcsA in an undescribed conformation. We show the AcuA•AcsA complex dissociates upon acetyl-coenzyme A (acetyl-CoA) dependent acetylation of AcsA by AcuA. We discover an intrinsic phosphotransacetylase activity enabling AcuA•AcsA generating acetyl-CoA from acetyl-phosphate (AcP) and coenzyme A (CoA) used by AcuA to acetylate and inactivate AcsA. Here, we provide mechanistic insights into the regulation of AMP-forming acetyl-CoA synthetases by lysine acetylation and discover an intrinsic phosphotransacetylase allowing modulation of its activity based on AcP and CoA levels. AMP-forming acetyl-CoA synthetase (AcsA) is an essential enzyme in all domains of life. Here, the authors provide mechanistic insights into regulation of AcsA by lysine acetylation, uncovering a regulatory phosphotransacetylase activity. [ABSTRACT FROM AUTHOR]

The function of proteins depends on their correct structure and proper dynamics. Understanding the dynamics of target proteins facilitates drug design and development. However, dynamic information is often hidden in the spatial structure of proteins. It is important but difficult to identify the specific residues that play a decisive role in protein dynamics. Here, we report that a critical glycine residue (Gly463) dominates the motion of threonyl-tRNA synthetase (ThrRS) and the sensitivity of the enzyme to antibiotics. Obafluorin (OB), a natural antibiotic, is a novel covalent inhibitor of ThrRS. The binding of OB induces a large conformational change in ThrRS. Through five crystal structures, biochemical and biophysical analyses, and computational simulations, we found that Gly463 plays an important role in the dynamics of ThrRS. Mutating this flexible residue into more rigid residues did not damage the enzyme's three-dimensional structure but significantly improved the thermal stability of the enzyme and suppressed its ability to change conformation. These mutations cause resistance of ThrRS to antibiotics that are conformationally selective, such as OB and borrelidin. This work not only elucidates the molecular mechanism of the self-resistance of OB-producing Pseudomonas fluorescens but also emphasizes the importance of backbone kinetics for aminoacyl-tRNA synthetase-targeting drug development. Crystal structures and molecular dynamics simulations reveal that a critical glycine residue dominates the motion of threonyl-tRNA synthetase and the sensitivity of the enzyme to conformation selective inhibitors. [ABSTRACT FROM AUTHOR]

Androgens have long been recognized as oncogenic agents. They can induce both benign and malignant hepatocellular neoplasms, including hepatocellular adenoma (HCA) and hepatocellular carcinoma, though the underlying mechanisms remain unclear. Androgen-induced liver tumors are most often solitary and clinically silent. Herein, we reported an androgen-induced HCA complicated by spontaneous rupture. The patient was a 24-year-old male presenting with fatigue, diminished libido, radiology-diagnosed hepatocellular adenomatosis for 3 years, and sudden-onset, severe, sharp, constant abdominal pain for one day. He used Aveed (testosterone undecanoate injection) from age 17 and completely stopped one year before his presentation. A physical exam showed touch pain and voluntary guarding in the right upper quadrant of the abdomen. An abdominal CT angiogram demonstrated multiple probable HCAs, with active hemorrhage of the largest one (6.6 × 6.2 × 5.1 cm) accompanied by large-volume hemoperitoneum. After being stabilized by a massive transfusion protocol and interventional embolization, he underwent a percutaneous liver core biopsy. The biopsy specimen displayed atypical hepatocytes forming dense cords and pseudoglands. The lesional cells diffusely stained β-catenin in nuclei and glutamine synthetase in cytoplasm. Compared to normal hepatocytes from control tissue, the tumor cells were positive for nuclear AR (androgen receptor) expression but had no increased EZH2 (Enhancer of Zeste 2 Polycomb Repressive Complex 2 Subunit) protein expression. The case indicated that androgen-induced hepatocellular neoplasms should be included in the differential diagnosis of acute abdomen. [ABSTRACT FROM AUTHOR]

The interplay between humans and their microbiome is crucial for various physiological processes, including nutrient absorption, immune defense, and maintaining homeostasis. Microbiome alterations can directly contribute to diseases or heighten their likelihood. This relationship extends beyond humans; microbiota play vital roles in other organisms, including eukaryotic pathogens causing severe diseases. Notably, Wolbachia, a bacterial microbiota, is essential for parasitic worms responsible for lymphatic filariasis and onchocerciasis, devastating human illnesses. Given the lack of rapid cures for these infections and the limitations of current treatments, new drugs are imperative. Here, we disrupt Wolbachia's symbiosis with pathogens using boron-based compounds targeting an unprecedented Wolbachia enzyme, leucyl-tRNA synthetase (LeuRS), effectively inhibiting its growth. Through a compound demonstrating anti-Wolbachia efficacy in infected cells, we use biophysical experiments and x-ray crystallography to elucidate the mechanism behind Wolbachia LeuRS inhibition. We reveal that these compounds form adenosine-based adducts inhibiting protein synthesis. Overall, our study underscores the potential of disrupting key microbiota to control infections. [ABSTRACT FROM AUTHOR]

Cholangiocarcinoma (CCA) is often diagnosed late, leading to incomplete tumor removal, drug resistance and reduced chemotherapy efficacy. Curcumin has the potential for anti-cancer activity through various therapeutic properties and can improve the efficacy of chemotherapy. We aimed to investigate the synergistic effect of a combination of curcumin and gemcitabine against CCA, targeting the LAT2/glutamine pathway. This combination synergistically suppressed proliferation in gemcitabine-resistant CCA cells (KKU-213BGemR). It also resulted in a remarkable degree of CCA cell apoptosis and cell cycle arrest, characterized by a high proportion of cells in the S and G2/M phases. Knockdown of SLC7A8 decreased the expressions of glutaminase and glutamine synthetase, resulting in inhibited cell proliferation and sensitized CCA cells to gemcitabine treatment. Moreover, in vivo experiments showed that a combination curcumin and gemcitabine significantly reduced tumor size, tumor growth rate and LAT2 expression in a gemcitabine-resistant CCA xenograft mouse model. Suppression of tumor progression in an orthotopic CCA hamster model provided strong support for clinical application. In conclusion, curcumin synergistically enhances gemcitabine efficacy against gemcitabine-resistant CCA by induction of apoptosis, partly via inhibiting LAT2/glutamine pathway. This approach may be an alternative strategy for the treatment of gemcitabine-resistant in CCA patients. [ABSTRACT FROM AUTHOR]

The glutamine synthetase/glutamic acid synthetase (GS/GOGAT) cycle plays important roles in N metabolism, growth, development, and stress resistance in plants. Excess ammonium (NH4+) restricts growth, but GS can help to alleviate its toxicity. In this study, the 84K model clone of hybrid poplar (Populus alba × P. tremula var. glandulosa), which has reduced biomass accumulation and leaf chlorosis under high-NH4+ stress, showed less severe symptoms in transgenic lines overexpressing GLUTAMINE SYNTHETASE 1;2 (GS1;2 -OE), and more severe symptoms in RNAi lines (GS1;2 -RNAi). Compared with the wild type, the GS1;2 -OE lines had increased GS and GOGAT activities and higher contents of free amino acids, soluble proteins, total N, and chlorophyll under high-NH4+ stress, whilst the antioxidant and NH4+ assimilation capacities of the GS1;2 -RNAi lines were decreased. The total C content and C/N ratio in roots and leaves of the overexpression lines were higher under stress, and there were increased contents of various amino acids and sugar alcohols, and reduced contents of carbohydrates in the roots. Under high-NH4+ stress, genes related to amino acid biosynthesis, sucrose and starch degradation, galactose metabolism, and the antioxidant system were significantly up-regulated in the roots of the overexpression lines. Thus, overexpression of GS1;2 affected the carbon and amino acid metabolism pathways under high-NH4+ stress to help maintain the balance between C and N metabolism and alleviate the symptoms of toxicity. Modification of the GS/GOGAT cycle by genetic engineering is therefore a potential strategy for improving the NH4+ tolerance of cultivated trees. [ABSTRACT FROM AUTHOR]

Cancer cells undergo metabolic adaptation to promote their survival and growth under energy stress conditions, yet the underlying mechanisms remain largely unclear. Here, we report that tripartite motif‐containing protein 2 (TRIM2) is upregulated in response to glutamine deprivation by the transcription factor cyclic AMP‐dependent transcription factor (ATF4). TRIM2 is shown to specifically interact with carnitine O‐palmitoyltransferase 1 (CPT1A), a rate‐limiting enzyme of fatty acid oxidation. Via this interaction, TRIM2 enhances the enzymatic activity of CPT1A, thereby regulating intracellular lipid levels and protecting cells from glutamine deprivation‐induced apoptosis. Furthermore, TRIM2 is able to promote both in vitro cell proliferation and in vivo xenograft tumor growth via CPT1A. Together, these findings establish TRIM2 as an important regulator of the metabolic adaptation of cancer cells to glutamine deprivation and implicate TRIM2 as a potential therapeutic target for cancer. [ABSTRACT FROM AUTHOR]

Glutamine‐addicted cancer metabolism is recently recognized as novel cancer target especially for KRAS and KEAP1 co‐occurring mutations. To identify more drug‐like GLS inhibitors, we report the amides in the wing macrocycles for GLS inhibition with unique SAR analysis. Although the amidotriazoles (amides in the wing) are in general less potent than those of acylaminothiadiazole analogs (reverse amides in the wing), macrocycle 4, 5, and 7 are selected as a potent macrocyclic GLS inhibitor in both biochemical and cell viability assays. Selected molecules result in partial reduction in intracellular glutamate levels in LR (LDK378‐resistant) cells which is consistent to their cells viability result. Finally, selected compounds reduce the growth of A549 and H460 cells which have co‐occurring mutations including KRAS and KEAP1. The putative binding mode of macrocycle 4 is also suggested using a molecular docking model. [ABSTRACT FROM AUTHOR]

Glutamine, the most abundant amino acid in the body, plays a critical role in preserving immune function, nitrogen balance, intestinal integrity, and resistance to infection. However, its limited solubility and instability present challenges for its use a functional nutrient. Consequently, there is a preference for utilizing glutamine‐derived peptides as an alternative to achieve enhanced functionality. This article aims to review the applications of glutamine monomers in clinical, sports, and enteral nutrition. It compares the functional effectiveness of monomers and glutamine‐derived peptides and provides a comprehensive assessment of glutamine‐derived peptides in terms of their classification, preparation, mechanism of absorption, and biological activity. Furthermore, this study explores the potential integration of artificial intelligence (AI)‐based peptidomics and synthetic biology in the de novo design and large‐scale production of these peptides. The findings reveal that glutamine‐derived peptides possess significant structure‐related bioactivities, with the smaller molecular weight fraction serving as the primary active ingredient. These peptides possess the ability to promote intestinal homeostasis, exert hypotensive and hypoglycemic effects, and display antioxidant properties. However, our understanding of the structure–function relationships of glutamine‐derived peptides remains largely exploratory at current stage. The combination of AI based peptidomics and synthetic biology presents an opportunity to explore the untapped resources of glutamine‐derived peptides as functional food ingredients. Additionally, the utilization and bioavailability of these peptides can be enhanced through the use of delivery systems in vivo. This review serves as a valuable reference for future investigations of and developments in the discovery, functional validation, and biomanufacturing of glutamine‐derived peptides in food science. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract The enzyme glutamine synthetase (GLN) is mainly responsible for the assimilation and reassimilation of nitrogen (N) in higher plants. Although the GLN gene has been identified in various plants, there is little information about the GLN family in cotton (Gossypium spp.). To elucidate the roles of GLN genes in cotton, we systematically investigated and characterized the GLN gene family across four cotton species (G. raimondii, G. arboreum, G. hirsutum, and G. barbadense). Our analysis encompassed analysis of members, gene structure, cis-element, intragenomic duplication, and exploration of collinear relationships. Gene duplication analysis indicated that segmental duplication was the primary driving force for the expansion of the GhGLN gene family. Transcriptomic and quantitative real-time reverse-transcription PCR (qRT-PCR) analyses indicated that the GhGLN1.1a gene is responsive to N induction treatment and several abiotic stresses. The results of virus-induced gene silencing revealed that the accumulation and N use efficiency (NUE) of cotton were affected by the inactivation of GhGLN1.1a. This study comprehensively analyzed the GhGLN genes in Gossypium spp., and provides a new perspective on the functional roles of GhGLN1.1a in regulating NUE in cotton.

The survival and proliferation of proliferating cancer cells is largely dependent on glutamine. Glutamine serves as a nitrogen source for the synthesis of amino acids and nucleotides, and as a carbon source for the synthesis of lipids. Virtual screening of FDA‐approved drugs is a promising approach to identify new glutaminase inhibitors. In this study, molecular docking were used to screen a library of FDA‐approved drugs against glutaminase. Their potential as inhibitors for the treatment of breast cancer was evaluated. Molecular dynamics simulations were performed on promising candidates. An in vitro study using two breast cancer cell lines, MDA‐MB‐231 and MCF‐7, was performed to evaluate the effect of the selected drugs on cell viability and expression of apoptosis‐related genes. Our results identified several FDA‐approved drugs with potential inhibitory activity against glutaminase, including bromocriptine, doxycycline, dutasteride, ezetimibe, fexofenadine, montelukast, pimozide, and tetracycline. In vitro assays revealed a dose‐dependent inhibitory effect of rifampin and bromocriptine, two drugs with the highest binding affinity to glutaminase, on cell viability and apoptosis‐related genes in breast cancer cell lines. Targeting glutaminase with FDA‐approved drugs may be a promising strategy for the development of new cancer therapies, especially for breast cancer. [ABSTRACT FROM AUTHOR]

Antifreeze proteins (AFPs) are found in a variety of marine cold‐water fishes where they prevent freezing by binding to nascent ice crystals. Their diversity (types I, II, III and antifreeze glycoproteins), as well as their scattered taxonomic distribution hint at their complex evolutionary history. In particular, type I AFPs appear to have arisen in response to the Late Cenozoic Ice Age that began ~ 34 million years ago via convergence in four different groups of fish that diverged from lineages lacking this AFP. The progenitor of the alanine‐rich α‐helical type I AFPs of sculpins has now been identified as lunapark, an integral membrane protein of the endoplasmic reticulum. Following gene duplication and loss of all but three of the 15 exons, the final exon, which encoded a glutamate‐ and glutamine‐rich segment, was converted to an alanine‐rich sequence by a combination of frameshifting and mutation. Subsequent gene duplications produced numerous isoforms falling into four distinct groups. The origin of the flounder type I AFP is quite different. Here, a small segment from the original antiviral protein gene was amplified and the rest of the coding sequence was lost, while the gene structure was largely retained. The independent origins of type I AFPs with up to 83% sequence identity in flounder and sculpin demonstrate strong convergent selection at the level of protein sequence for alanine‐rich single alpha helices that bind to ice. Recent acquisition of these AFPs has allowed sculpins to occupy icy seawater niches with reduced competition and predation from other teleost species. [ABSTRACT FROM AUTHOR]

(±)‐Penindolenes A−D (1–4), the first representatives of indole terpenoids featuring a γ‐lactam skeleton, were isolated from the mangrove‐derived endophytic fungus Penicillium brocae MA‐231. Our bioactivity tests revealed their potent antimicrobial and acetylcholinesterase inhibitory activities. The biosynthetic reactions by the five enzymes PbaABCDE leading to γ‐lactam ring formation were identified with heterologous expression and in vitro enzymatic assays. Remarkably, the cytochrome P450 monooxygenase PbaB and its homolog in Aspergillus oryzae catalyzed the 2,3‐cleavage of the indole ring to generate two keto groups in 1. This is the first example of the oxidative cleavage of indole by a P450 monooxygenase. In addition, rare secondary amide bond formation by the glutamine synthetase‐like enzyme PbaD was reported. These findings will contribute to the engineered biosynthesis of unnatural, bioactive indole terpenoids. [ABSTRACT FROM AUTHOR]

Our previous study highlighted the therapeutic potential of glutathione (GSH), an intracellular thiol tripeptide ubiquitous in mammalian tissues, in mitigating hepatic and cerebral damage. Building on this premise, we posited the hypothesis that GSH could be a promising candidate for treating acute hepatic encephalopathy (AHE). To verify this conjecture, we systematically investigated the feasibility of GSH as a therapeutic agent for AHE through comprehensive pharmacokinetic, pharmacodynamic, and mechanistic studies using a thioacetamide-induced AHE rat model. Our pharmacodynamic data demonstrated that oral GSH could significantly improve behavioral scores and reduce hepatic damage of AHE rats by regulating intrahepatic ALT, AST, inflammatory factors, and homeostasis of amino acids. Additionally, oral GSH demonstrated neuroprotective effects by alleviating the accumulation of intracerebral glutamine, down-regulating glutamine synthetase, and reducing taurine exposure. Pharmacokinetic studies suggested that AHE modeling led to significant decrease in hepatic and cerebral exposure of GSH and cysteine. However, oral GSH greatly enhanced the intrahepatic and intracortical GSH and CYS in AHE rats. Given the pivotal roles of CYS and GSH in maintaining redox homeostasis, we investigated the interplay between oxidative stress and pathogenesis/ treatment of AHE. Our data revealed that GSH administration significantly relieved oxidative stress levels caused by AHE modeling via down-regulating the expression of NADPH oxidase 4 (NOX4) and NF-κB P65. Importantly, our findings further suggested that GSH administration significantly regulated the excessive endoplasmic reticulum (ER) stress caused by AHE modeling through the iNOS/ATF4/Ddit3 pathway. In summary, our study uncovered that exogenous GSH could stabilize intracerebral GSH and CYS levels to act on brain oxidative and ER stress, which have great significance for revealing the therapeutic effect of GSH on AHE and promoting its further development and clinical application. [ABSTRACT FROM AUTHOR]

Salt stress seriously affects crop growth, leading to a decline in crop quality and yield. Application of exogenous substances to improve the salt tolerance of crops and promote their growth under salt stress has become a widespread and effective means. Eugenol is a small molecule of plant origin with medicinal properties such as antibacterial, antiviral, and antioxidant properties. In this study, tobacco seedlings were placed in Hoagland's solution containing NaCl in the presence or absence of eugenol, and physiological indices related to stress tolerance were measured along with transcriptome sequencing. The results showed that eugenol improved the growth of tobacco seedlings under salt stress. It promoted carbon and nitrogen metabolism, increased the activities of nitrate reductase (NR), sucrose synthase (SS), and glutamine synthetase (GS) by 31.03, 5.80, and 51.06%. It also activated the enzymatic and non-enzymatic antioxidant systems, reduced the accumulation of reactive oxygen species in the tobacco seedlings, and increased the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) by 24.38%, 18.22%, 21.60%, and 28.8%, respectively. The content of glutathione (GSH) was increased by 29.49%, and the content of superoxide anion (O2−) and malondialdehyde (MDA) were reduced by 29.83 and 33.86%, respectively. Promoted osmoregulation, the content of Na+ decreased by 34.34, K+ increased by 41.25%, and starch and soluble sugar increased by 7.72% and 25.42%, respectively. It coordinated hormone signaling in seedlings; the content of abscisic acid (ABA) and gibberellic acid 3 (GA3) increased by 51.93% and 266.28%, respectively. The transcriptome data indicated that the differentially expressed genes were mainly enriched in phenylpropanoid biosynthesis, the MAPK signaling pathway, and phytohormone signal transduction pathways. The results of this study revealed the novel role of eugenol in regulating plant resistance and provided a reference for the use of exogenous substances to alleviate salt stress. [ABSTRACT FROM AUTHOR]

Glutamine synthetase (GS) is a key enzyme involved in nitrogen metabolism. GS can be divided into cytosolic and plastidic subtypes and has been reported to respond to various biotic and abiotic stresses. However, little research has been reported on the function of GS in mulberry. In this study, the full length of MaGS2 was cloned, resulting in 1302 bp encoding 433 amino acid residues. MaGS2 carried the typical GS2 motifs and clustered with plastidic-subtype GSs in the phylogenetic analysis. MaGS2 localized in chloroplasts, demonstrating that MaGS2 is a plastidic GS. The expression profile showed that MaGS2 is highly expressed in sclerotiniose pathogen-infected fruit and sclerotiniose-resistant fruit, demonstrating that MaGS2 is associated with the response to sclerotiniose in mulberry. Furthermore, the overexpression of MaGS2 in tobacco decreased the resistance against Ciboria shiraiana, and the knockdown of MaGS2 in mulberry by VIGS increased the resistance against C. shiraiana, demonstrating the role of MaGS2 as a negative regulator of mulberry resistance to C. shiraiana infection. [ABSTRACT FROM AUTHOR]

The elucidation of disease pathogenesis can be achieved by analyzing the low-abundance phosphopeptides in organisms. Herein, we developed a novel and easy-to-prepare polymer-coated nanomaterial. By improving the hydrophilicity and spatial conformation of the material, we effectively enhanced the adsorption of phosphopeptides and demonstrated excellent enrichment properties. The material was able to successfully enrich the phosphopeptides in only 1 min. Meanwhile, the material has high selectivity (1:2000), good loading capacity (100 μg/mg), excellent sensitivity (0.5 fmol), and great acid and alkali resistance. In addition, the material was applied to real samples, and 70 phosphopeptides were enriched from the serum of Parkinson's disease (PD) patients and 67 phosphopeptides were enriched from the serum of normal controls. Sequences Logo showed that PD is probably associated with threonine, glutamate, serine, and glutamine. Finally, gene ontology (GO) analysis was performed on phosphopeptides enriched in PD patients' serum. The results showed that PD patients expressed abnormal expression of the cholesterol metabolic process and cell–matrix adhesion in the biological process (BP), endoplasmic reticulum and lipoprotein in the cellular component (CC), and heparin-binding, lipid-binding, and receptor-binding in the molecular function (MF) as compared with normal individuals. All the experiments indicate that the nanomaterials have great potential in proteomics studies. [ABSTRACT FROM AUTHOR]

Persister cells are transiently tolerant to antibiotics and are associated with recalcitrant chronic infections due to recolonization of host cells after antibiotic removal. Brucella spp. are facultative pathogens that establish intracellular infection cycles in host cells which results in chronic persistent infections. Brucella abortus forms multi-drug persister cells which are promoted by the (p) ppGpp synthetase Rsh during rifampicin exposure. Here, we confirmed that Rsh promoted persister cells formation in B. abortus stationary phase treated with rifampicin and enrofloxacin. Deletion of the gene for Rsh decreased persister cells level in the presence of these drugs in different growth phases. However, persister cells formation by deletion strain varied in different growth phases in the presence of other antibiotics. Rsh also was involved in persister cells formation during rifampicin treatment under certain stress conditions, including acidic conditions, exposure to PBS, and heat stress. Moreover, Rsh impacted persister cell levels during rifampicin or enrofloxacin treatment in RAW264.7 macrophages. Certain typeIItoxin-antitoxin modules were upregulated under various stress conditions in B. abortus. We established that Rsh positively regulated the type II toxin-antitoxin mbcTA. Moreover, rifampicin-tolerant persister cells formation was elevated and ATP levels were decreased when mbcTA promoter was overexpressed in Rsh deletion background in stationary phase. Our results establish that (p)ppGpp synthetase Rsh plays a key role in B. abortus persistence and may serve as a potent novel target in combination with rifampicin in the development of new therapeutic approaches and prevention strategies to treat chronic infections of Brucella. [ABSTRACT FROM AUTHOR]

Diabetic retinopathy (DR) is a significant complication of diabetes that often leads to blindness, impacting Müller cells, the primary retinal macroglia involved in DR pathogenesis. Reactive oxygen species (ROS) play a crucial role in the development of DR. The objective of this study was to investigate the involvement of sestrin2 in DR using a high‐glucose (HG)‐induced Müller cell model and assessing cell proliferation with 5‐ethynyl‐2‐deoxyuridine (EdU) labeling. Following this, sestrin2 was upregulated in Müller cells to investigate its effects on ROS, tube formation, and inflammation both in vitro and in vivo, as well as its interaction with the nuclear factor erythroid2‐related factor 2 (Nrf2) signaling pathway. The findings demonstrated a gradual increase in the number of EdU‐positive cells over time, with a subsequent decrease after 72 h of exposure to high glucose levels. Additionally, the expression of sestrin2 exhibited a progressive increase over time, followed by a decrease at 72 h. The rh‐sestrin2 treatment suppressed the injury of Müller cells, decreased ROS level, and inhibited the tube formation. Rh‐sestrin2 treatment enhanced the expression of sestrin2, Nrf2, heme oxygenase‐1 (HO‐1), and glutamine synthetase (GS); however, the ML385 treatment reversed the protective effect of rh‐sestrin2. Finally, we evaluated the effect of sestrin2 in a DR rat model. Sestrin2 overexpression treatment improved the pathological injury of retina and attenuated the oxidative damage and inflammatory reaction. Our results highlighted the inhibitory effect of sestrin2 in the damage of retina, thus presenting a novel therapeutic sight for DR. Significance statement: Diabetic retinopathy (DR) is a microvascular complication associated with diabetes. Müller cells serve as the basically glial cells within the retina. Alterations in the retinal environment can impact the functionality and well‐being of Müller cells, subsequently affecting the overall health of the retina. Sestrin2, a stress‐induced metabolic protein with high conservation, has the ability to suppress oxygen species and offer cellular protection against diverse detrimental stimuli. Consequently, it is necessary to confirm the impact of sestrin2 on the Müller cells in the context of DR. [ABSTRACT FROM AUTHOR]

Incidences of drug-resistant tuberculosis have become common and are rising at an alarming rate. Aminoacyl t-RNA synthetase has been validated as a newer target against Mycobacterium tuberculosis. Leucyl t-RNA synthetase (LeuRS) is ubiquitously found in all organisms and regulates transcription, protein synthesis, mitochondrial RNA cleavage, and proofreading of matured t-RNA. Leucyl t-RNA synthetase promotes growth and development and is the key enzyme needed for biofilm formation in Mycobacterium. Inhibition of this enzyme could restrict the growth and development of the mycobacterial population. A database consisting of 2734 drug-like molecules was screened against leucyl t-RNA synthetase enzymes through virtual screening. Based on the docking scores and MMGBSA energy values, the top three compounds were selected for molecular dynamics simulation. The druggable nature of the top three hits was confirmed by predicting their pharmacokinetic parameters. The top three hits—compounds 1035 (ZINC000001543916), 1054 (ZINC000001554197), and 2077 (ZINC000008214483)—were evaluated for their binding affinity toward leucyl t-RNA synthetase by an isothermal titration calorimetry study. The inhibitory activity of these compounds was tested against antimycobacterial activity, biofilm formation, and LeuRS gene expression potential. Compound 1054 (Macimorelin) was found to be the most potent molecule, with better antimycobacterial activity, enzyme binding affinity, and significant inhibition of biofilm formation, as well as inhibition of the LeuRS gene expression. Compound 1054, the top hit compound, has the potential to be used as a lead to develop successful leucyl t-RNA synthetase inhibitors. [ABSTRACT FROM AUTHOR]

Despite global warming, the response of rice yield to long-term warming in cool regions and its physiological mechanisms remain unknown. This study used the widely cultivated japonica rice Jiyang100 in Northeast China. Taking rice grown under natural temperatures as a control (CK), field warming treatments were conducted at the tillering-panicle initiation (T1), whole growth (T2), and grain-filling (T3) stages. The positive effects of T1, T2, and T3 on the total number of spikelets per hole increased the yield in both years, with average increases of 11.5%, 9.9% and 6.5% compared to CK, respectively. Warming treatments improved the stay-green traits, photosynthesis, sucrose synthesis, and nitrogen metabolism of rice. The yield was positively correlated with the relative chlorophyll content (SPAD), soluble sugar content, sucrose content, and the activities of sucrose phosphate synthase (SPS), nitrate reductase (NR), glutamine synthetase (GS), glutamine oxoglutarate aminotransferase (GOGAT) in flag leaves. In addition, SPAD had a positive correlation with soluble sugar content, soluble protein content, and the activities of NR, GS, GOGAT, glutamate dehydrogenase (GDH), but a negative correlation with acid invertase (AI) activity. The stay-green ability was positively correlated to the net photosynthetic rate (Pn), soluble sugar content and soluble protein content. The coupling interactions of stay-green traits, nitrogen and carbon metabolism increased the yield potential and yield supply capacity, increased yield under long-term warming conditions in the cool regions. Under gradual warming, the physiological response of rice in cool regions promotes plant growth and development, thereby increasing yield. [ABSTRACT FROM AUTHOR]

Rice is essential to feed the world's population, being the most important staple food in several countries. Crop production has been directly impacted by climate change. Plants can mitigate an increase in atmospheric CO2 concentration through photosynthetic conversion into carbohydrates. However, the potential for this conversion and plant responses to climate change remain unclear. The study was conducted from the cultivation of plants in open-top chambers (OTCs) with two concentrations of CO2, 400 ppm (ambient – a[CO2]) and 700 ppm (enhanced – e[CO2])). We used rice plants of the cultivar IRGA 424 RI. Evaluations occurred in the vegetative (V5 and V11) and reproductive (R2 and R7) stages. As for gas exchange, plants grown under e[CO2] showed increased net CO2 assimilation rate, greater water use efficiency, and higher intercellular CO2 concentration. On the other hand, the lowest values for stomatal conductance, chlorophyll index, nitrogen balance index, percentage of nitrogen in the leaves, and thousand-grain weight were found for this treatment. In addition, there was an increase in the activity of the glutamine synthetase and nitrate reductase enzymes in leaves and roots under e[CO2], as well as a higher content of nitrate, starch, water-soluble polysaccharides and total soluble sugars in leaves in the first evaluated phenological stage. These results showed us that the reductions in chlorophyll levels added to the stimulation of the photosynthetic machinery elevated the nutritional demand. Due to these impacts, nitrogen and carbon metabolism were reduced, negatively reflecting on the yield components of rice plants. [ABSTRACT FROM AUTHOR]

Although valproic acid is generally well tolerated, hepatotoxicity is a common side effect in patients receiving long-term treatment. However, the mechanisms underlying valproic acid-associated hepatotoxicity remain elusive. To investigate the mechanisms and explore the potential risk factors for valproic acid-associated hepatotoxicity, 165 age-matched pediatric patients were recruited for laboratory tests and glutamate-glutamine cycle analysis. The concentration of glutamate in patients with hepatotoxicity was significantly greater than that in control patients, while the concentration of glutamine in patients with hepatotoxicity was significantly lower than that in control patients (P <0.05). In addition, the frequencies of the heterozygous with one mutant allele and homozygous with two mutant alleles genotypes in glutamate-ammonia ligase rs10911021 were significantly higher in the hepatotoxicity group than those in the control group (47.1 percent versus 32.5 percent, P = 0.010; 17.6 percent versus 5.2 percent, P = 0.001, respectively). Moreover, heterozygous carriers with one mutant allele and homozygous carriers with two mutant alleles genotypes of glutamate-ammonia ligase rs10911021 exhibited significant differences in the concentrations of glutamine and glutamate concentrations (P ˂ 0.001 and P = 0.001, respectively) and liver function indicators (activities of aspartate aminotransferase, alanine aminotransferase, and gamma-glutamyl transferase, P <0.001, respectively). Furthermore, logistic regression analysis indicated that glutamate-ammonia ligase rs10911021 (P = 0.002, odds ratio: 3.027, 95 percent confidence interval, 1.521 − 6.023) and glutamate (P = 0.001, odds ratio: 2.235, 95 percent confidence interval, 1.369 − 3.146) were associated with a greater risk for hepatotoxicity, while glutamine concentrations were negatively associated with hepatotoxicity (P = 0.001, odds ratio: 0.711, 95 percent confidence interval, 0.629 − 0.804). Understanding pharmacogenomic risks for valproic acid induced hepatotoxicity might help direct patient specific care. Limitations of our study include the exclusive use of children from one location and concomitant medication use in many patients. Perturbation of the glutamate-glutamine cycle is associated with valproic acid-associated hepatotoxicity. Moreover, glutamate-ammonia ligase rs10911021, glutamate and glutamine concentrations are potential risk factors for valproic acid-associated hepatotoxicity. [ABSTRACT FROM AUTHOR]

The central nervous system of Pacific salmon retains signs of embryonic structure throughout life and a large number of neuroepithelial neural stem cells (NSCs) in the proliferative areas of the brain, in particular. However, the adult nervous system and neurogenesis studies on rainbow trout, Oncorhynchus mykiss, are limited. Here, we studied the localization of glutamine synthetase (GS), vimentin (Vim), and nestin (Nes), as well as the neurons formed in the postembryonic period, labeled with doublecortin (DC), under conditions of homeostatic growth in adult cerebellum and brainstem of Oncorhynchus mykiss using immunohistochemical methods and Western Immunoblotting. We observed that the distribution of vimentin (Vim), nestin (Nes), and glutamine synthetase (GS), which are found in the aNSPCs of both embryonic types (neuroepithelial cells) and in the adult type (radial glia) in the cerebellum and the brainstem of trout, has certain features. Populations of the adult neural stem/progenitor cells (aNSPCs) expressing GS, Vim, and Nes have different morphologies, localizations, and patterns of cluster formation in the trout cerebellum and brainstem, which indicates the morphological and, obviously, functional heterogeneity of these cells. Immunolabeling of PCNA revealed areas in the cerebellum and brainstem of rainbow trout containing proliferating cells which coincide with areas expressing Vim, Nes, and GS. Double immunolabeling revealed the PCNA/GS PCNA/Vim coexpression patterns in the neuroepithelial-type cells in the PVZ of the brainstem. PCNA/GS coexpression in the RG was detected in the submarginal zone of the brainstem. The results of immunohistochemical study of the DC distribution in the cerebellum and brainstem of trout have showed a high level of expression of this marker in various cell populations. This may indicate: (i) high production of the adult-born neurons in the cerebellum and brainstem of adult trout, (ii) high plasticity of neurons in the cerebellum and brainstem of trout. We assume that the source of new cells in the trout brain, along with PVZ and SMZ, containing proliferating cells, may be local neurogenic niches containing the PCNA-positive and silent (PCNA-negative), but expressing NSC markers, cells. The identification of cells expressing DC, Vim, and Nes in the IX-X cranial nerve nuclei of trout was carried out. [ABSTRACT FROM AUTHOR]

Background: Salt stress is one of the most common abiotic stresses, reducing plant growth and productivity. Thus, the development of suitable management practices to minimize the deleterious effects of salt stress has become necessary. Aims: This study was conducted to investigate the possible mechanisms underlying salt tolerance conferred by jasmonic acid (JA). Methods: Salt‐stressed wheat seedlings were supplemented with 1 mM JA and/or 1 mM ibuprofen (IBU), an inhibitor of endogenous JA biosynthesis, in the culture medium. Results: The obtained results showed that salt stress significantly decreased shoot and root dry weight production and relative water contents. This was associated with a noteworthy reduction in leaf and root ascorbate (AsA) concentrations, as well as glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) activities. Exogenously supplied JA did not affect GS and GOGAT activities in leaves and roots of salt‐treated seedlings. However, noticeable enhancements were observed in growth, AsA concentrations, as well as GDH activities. Likewise, the inhibition of JA biosynthesis by IBU application was accompanied by a significant decrease in seedlings' growth associated with a noticeable reduction in AsA concentrations and GDH activities. The decreases in growth and GDH activities were also obtained following inhibition of AsA biosynthesis by lycorine (Lyc) application. By contrast, increased GDH activities and enhanced growth were obtained following exogenous AsA supplementation, with or without JA biosynthesis inhibition. Conclusions: The findings implied that exogenous JA enhanced AsA biosynthesis and induced GDH activity, which further promoted the growth of wheat seedlings in salt‐stressed conditions. Therefore, the stimulation of AsA biosynthesis and GDH activity through JA application in the rhizosphere may be suggested as a vital strategy for strengthening the salt tolerance of wheat plants, at least at the seedling stage. [ABSTRACT FROM AUTHOR]

Nuclear factor erythroid 2-related factor 2 (NRF2) hyperactivation has been established as an oncogenic driver in a variety of human cancers, including non-small cell lung cancer (NSCLC). However, despite massive efforts, no specific therapy is currently available to target NRF2 hyperactivation. Here, we identify peptidylprolyl isomerase A (PPIA) is required for NRF2 protein stability. Ablation of PPIA promotes NRF2 protein degradation and blocks NRF2-driven growth in NSCLC cells. Mechanistically, PPIA physically binds to NRF2 and blocks the access of ubiquitin/Kelch Like ECH Associated Protein 1 (KEAP1) to NRF2, thus preventing ubiquitin-mediated degradation. Our X-ray co-crystal structure reveals that PPIA directly interacts with a NRF2 interdomain linker via a trans-proline 174-harboring hydrophobic sequence. We further demonstrate that an FDA-approved drug, cyclosporin A (CsA), impairs the interaction of NRF2 with PPIA, inducing NRF2 ubiquitination and degradation. Interestingly, CsA interrupts glutamine metabolism mediated by the NRF2/KLF5/SLC1A5 pathway, consequently suppressing the growth of NRF2-hyperactivated NSCLC cells. CsA and a glutaminase inhibitor combination therapy significantly retard tumor progression in NSCLC patient-derived xenograft (PDX) models with NRF2 hyperactivation. Our study demonstrates that targeting NRF2 protein stability is an actionable therapeutic approach to treat NRF2-hyperactivated NSCLC. Despite being an established oncogenic driver of non-small cell lung cancer (NSCLC), therapies targeting NRF2 hyperactivation are lacking. Here, the authors identify peptidylprolyl isomerase A (PPIA) as a mediator of NRF2 stability and demonstrate the efficacy of targeting this interaction with cyclosporin A in preclinical models of NSCLC. [ABSTRACT FROM AUTHOR]

Nε -lysine acetylation is recognized as a prevalent post-translational modification (PTM) that regulates proteins across all three domains of life. In Bacillus subtilis, the histone-like protein HBsu is acetylated at seven sites, which regulates DNA compaction and the process of sporulation. In Mycobacteria, DNA compaction is a survival strategy in response antibiotic exposure. Acetylation of the HBsu ortholog HupB decondenses the chromosome to escape this drug-induced, non-growing state, and in addition, regulates the formation of drug-tolerant subpopulations by altering gene expression. We hypothesized that the acetylation of HBsu plays similar regulatory roles. First, we measured nucleoid area by fluorescence microscopy and in agreement, we found that wild-type cells compacted their nucleoids upon kanamycin exposure, but not exposure to tetracycline. We analyzed a collection of HBsu mutants that contain lysine substitutions that mimic the acetylated (glutamine) or unacetylated (arginine) forms of the protein. Our findings indicate that some level of acetylation is required at K3 for a proper response and K75 must be deacetylated. Next, we performed time-kill assays of wild-type and mutant strains in the presence of different antibiotics and found that interfering with HBsu acetylation led to faster killing rates. Finally, we examined the persistent subpopulation and found that altering the acetylation status of HBsu led to an increase in persister cell formation. In addition, we found that most of the deacetylation-mimic mutants, which have compacted nucleoids, were delayed in resuming growth following removal of the antibiotic, suggesting that acetylation is required to escape the persistent state. Together, this data adds an additional regulatory role for HBsu acetylation and further supports the existence of a histone-like code in bacteria. [ABSTRACT FROM AUTHOR]

Background: Glutamine synthetase (GS), glutamate synthase (GOGAT), and nitrate reductase (NR) are key enzymes involved in nitrogen assimilation and metabolism in plants. However, the systematic analysis of these gene families lacked reports in soybean (Glycine max (L.) Merr.), one of the most important crops worldwide. Methods: In this study, we performed genome-wide identification and characterization of GS, GOGAT, and NR genes in soybean under abiotic and nitrogen stress conditions. Results: We identified a total of 10 GS genes, six GOGAT genes, and four NR genes in the soybean genome. Phylogenetic analysis revealed the presence of multiple isoforms for each gene family, indicating their functional diversification. The distribution of these genes on soybean chromosomes was uneven, with segmental duplication events contributing to their expansion. Within the nitrogen assimilation genes (NAGs) group, there was uniformity in the exon-intron structure and the presence of conserved motifs in NAGs. Furthermore, analysis of cis-elements in NAG promoters indicated complex regulation of their expression. RT-qPCR analysis of seven soybean NAGs under various abiotic stresses, including nitrogen deficiency, drought-nitrogen, and salinity, revealed distinct regulatory patterns. Most NAGs exhibited up-regulation under nitrogen stress, while diverse expression patterns were observed under salt and drought-nitrogen stress, indicating their crucial role in nitrogen assimilation and abiotic stress tolerance. These findings offer valuable insights into the genomic organization and expression profiles of GS, GOGAT, and NR genes in soybean under nitrogen and abiotic stress conditions. The results have potential applications in the development of stress-resistant soybean varieties through genetic engineering and breeding. [ABSTRACT FROM AUTHOR]

A pathway frequently altered in cancer is glutaminolysis, whereby glutaminase (GA) catalyzes the main step as follows: the deamidation of glutamine to form glutamate and ammonium. There are two types of GA isozymes, named GLS and GLS2, which differ considerably in their expression patterns and can even perform opposing roles in cancer. GLS correlates with tumor growth and proliferation, while GLS2 can function as a context-dependent tumor suppressor. However, both isoenzymes have been described as essential molecules handling oxidant stress because of their involvement in glutathione production. We reviewed the literature to highlight the critical roles of GLS and GLS2 in restraining ROS and regulating both cellular signaling and metabolic stress due to their function as indirect antioxidant enzymes, as well as by modulating both reductive carboxylation and ferroptosis. Blocking GA activity appears to be a potential strategy in the dual activation of ferroptosis and inhibition of cancer cell growth in a ROS-mediated mechanism. [ABSTRACT FROM AUTHOR]

In this study, a synergist made of itaconic acid, maleic acid, acrylic acid and other active ingredients polymerised was sprayed on the surface of nitrogen (N) fertiliser particles to make synergistic nitrogen fertilisers (SNF). To explore the effect of SNF on N metabolism of wheat in saline alkaline land, five treatments were set up: CK - ordinary N fertiliser (299.86 kg N/ha); T1 - SNF (299.86 kg N/ha); T2 - SNF (239.89 kg N/ha); T3 - SNF (179.92 kg N/ha); T4 - SNF (119.94 kg N/ha). The aboveground dry weight of wheat, the photosynthetic characteristics of wheat flag leaves, the activity of the N metabolism enzyme of wheat flag leaves, the expression of N transporter-related genes in wheat roots, and the N accumulation and transport of plants were determined. The results showed that the T1 treatment performed the best. During the two years, the N translocation from stems and leaves to spikes of plants at maturity in T1 was 33.18-45.55% higher than that of CK. The N content of wheat spikes was 12.01-12.66% higher than that of CK. The activities of nitrate reductase, glutamine synthetase, glutamate synthetase and the expression of nitrate transporter gene TaNRT1.1 and ammonium transporter gene TaAMT1.1 were significantly higher than that of CK. The aboveground dry weight of wheat and photosynthetic characteristics of flag leaves were significantly higher than those of CK in T1, whereas the intercellular CO2 concentration was significantly lower than that of CK. The application of SNF positively affected N accumulation and transport in wheat, wheat yield, and fertiliser utilisation, as well as reduced N loss in saline alkaline land. [ABSTRACT FROM AUTHOR]

The present study evaluated the antiseizure and neuroprotective effects of sodium houttuyfonate (SH), a derivative of Houttuynia cordata Thunb. (H. cordata), in a kainic acid (KA)- induced seizure rat model and its underlying mechanism. Sprague Dawley rats were administered normal saline, SH (50 or 100 mg/kg), or carbamazepine (300 mg/kg) by oral gavage for seven consecutive days before the intraperitoneal administration of KA (15 mg/kg). SH showed antiseizure effects at a dose of 100 mg/kg; it prolonged seizure latency and decreased seizure scores. SH also significantly decreased neuronal loss in the hippocampi of KA-treated rats, which was associated with the prevention of glutamate level increase, the upregulation of glutamate reuptake-associated proteins (excitatory amino acid transporters 1–3), glutamate metabolism enzyme glutamine synthetase, the downregulation of the glutamate synthesis enzyme glutaminase, and significant alterations in the expression of AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor) and NMDA (N-methyl-D-aspartic acid receptor) receptor subunits in the hippocampus. Furthermore, the effects of SH were similar to those of the antiseizure drug carbamazepine. Therefore, the results of the present study suggest that SH has antiseizure effects on KA-induced seizures, possibly through the prevention of glutamatergic alterations. Our findings suggest that SH is a potential alternative treatment that may prevent seizures by preserving the normal glutamatergic system. [ABSTRACT FROM AUTHOR]

Aim: Idiopathic non-cirrhotic portal hypertension (INCPH) is a vascular disorder of uncertain origin. Diagnosis can be challenging on liver biopsy. Despite diverse histomorphologic findings documented in literature, studies on the frequency of these findings are lacking. This study aims to assess both the histomorphologic features and the immunoexpression patterns of CD34 and glutamine synthetase (GS) in liver biopsies and searched for their contribution to the pathologic diagnosis of INCPH. Materials and methods: Hematoxylin–eosin, CD34, and GS-stained liver needle biopsy sections of 16 patients clinically diagnosed with INCPH were retrospectively analyzed. Histologic findings such as portal vein narrowing, obliteration, or loss were grouped as major findings, while portal vein herniation, hypervascularized portal tracts, and periportal abnormal vessels were grouped as minor findings, and their frequency were evaluated. Periportal endothelial CD34 stained areas were measured via ocular micrometer. The distribution of GS immunoexpression was evaluated. Eighteen healthy liver donor biopsies were evaluated as controls. Results: In INCPH cases, 58% of portal tracts showed major findings, compared to 15% in the control group (p < 0.001). Minor findings were observed in 16% of INCPH cases and 7% of controls (p = 0.014). The number of portal tracts with histologic findings is significantly higher in INCPH than in control liver biopsies. Abnormal portal tract distribution, like being close to each other, was seen in 75% of INCPH cases but not in controls (p < 0.001). Nodular regenerative hyperplasia (NRH) was present in 31% of cases. Periportal CD34 expression was higher in INCPH, and affected areas were larger than in controls (p < 0.001). Irregular GS staining, i.e. GS staining with patchy distribution in zone 3, and/or periportal and zone 2 hepatocytes, was found in 62% of INCPH cases, while controls showed the usual pattern (p < 0.001). Conclusion: In the biopsy diagnosis of INCPH, in addition to the presence of major histologic findings and the amount of portal tracts displaying these features, the expression of endothelial CD34 in periportal areas, and irregular hepatocellular GS expression can also be considered as supporting feature. [ABSTRACT FROM AUTHOR]

Polyglutamine diseases comprise a cluster of genetic disorders involving neurodegeneration and movement disabilities. In polyglutamine diseases, the target proteins become aberrated due to polyglutamine repeat formation. These aberrant proteins form the root cause of associated complications. The metabolic regulation during polyglutamine diseases is not well studied and needs more attention. We have brought to light the significance of regulating glutamine metabolism during polyglutamine diseases, which could help in decreasing the neuronal damage associated with excess glutamate and nucleotide generation. Most polyglutamine diseases are accompanied by symptoms that occur due to excess glutamate and nucleotide accumulation. Along with a dysregulated glutamine metabolism, the Nicotinamide adenine dinucleotide (NAD+) levels drop down, and, under these conditions, NAD+ supplementation is the only achievable strategy. NAD+ is a major co-factor in the glutamine metabolic pathway, and it helps in maintaining neuronal homeostasis. Thus, strategies to decrease excess glutamate and nucleotide generation, as well as channelizing glutamine toward the generation of ATP and the maintenance of NAD+ homeostasis, could aid in neuronal health. Along with understanding the metabolic dysregulation that occurs during polyglutamine diseases, we have also focused on potential therapeutic strategies that could provide direct benefits or could restore metabolic homeostasis. Our review will shed light into unique metabolic causes and into ideal therapeutic strategies for treating complications associated with polyglutamine diseases. [ABSTRACT FROM AUTHOR]

The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate (cGMP) affinity chromatography approach, namely, soluble starch synthase STA3, starch‐branching enzyme SBE1, and α‐amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L‐glutamine (Gln). This activating effect required the enzyme's N‐terminal aspartate kinase–chorismate mutase–tyrA domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N‐containing molecules but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N and C metabolism at the enzymatic level, increasing the liberation of C skeletons from starch when high Gln levels signal an abundance of assimilated N. [ABSTRACT FROM AUTHOR]

Leaf yellowing is a well-known phenotype that attracts phloem-feeding insects. However, it remains unclear how insect-vectored plant pathogens induce host leaf yellowing to facilitate their own transmission by insect vectors. Here, we report that an effector protein secreted by rice orange leaf phytoplasma (ROLP) inhibits chlorophyll biosynthesis and induces leaf yellowing to attract leafhopper vectors, thereby presumably promoting pathogen transmission. This effector, designated secreted ROLP protein 1 (SRP1), first secreted into rice phloem by ROLP, was subsequently translocated to chloroplasts by interacting with the chloroplastic glutamine synthetase (GS2). The direct interaction between SRP1 and GS2 disrupts the decamer formation of the GS2 holoenzyme, attenuating its enzymatic activity, thereby suppressing the synthesis of chlorophyll precursors glutamate and glutamine. Transgenic expression of SRP1 in rice plants decreased GS2 activity and chlorophyll precursor accumulation, finally inducing leaf yellowing. This process is correlated with the previous evidence that the knockout of GS2 expression in rice plants causes a similar yellow chlorosis phenotype. Consistently, these yellowing leaves attracted higher numbers of leafhopper vectors, caused the vectors to probe more frequently, and presumably facilitate more efficient phytoplasma transmission. Together, these results uncover the mechanism used by phytoplasmas to manipulate the leaf color of infected plants for the purpose of enhancing attractiveness to insect vectors. [ABSTRACT FROM AUTHOR]

There is a lack of systematic research exploring cross-species variation in liver lobular geometry and zonation patterns of critical drug-metabolizing enzymes, a knowledge gap essential for translational studies. This study investigated the critical interplay between lobular geometry and key cytochrome P450 (CYP) zonation in four species: mouse, rat, pig, and human. We developed an automated pipeline based on whole slide images (WSI) of hematoxylin-eosin-stained liver sections and immunohistochemistry. This pipeline allows accurate quantification of both lobular geometry and zonation patterns of essential CYP proteins. Our analysis of CYP zonal expression shows that all CYP enzymes (besides CYP2D6 with panlobular expression) were observed in the pericentral region in all species, but with distinct differences. Comparison of normalized gradient intensity shows a high similarity between mice and humans, followed by rats. Specifically, CYP1A2 was expressed throughout the pericentral region in mice and humans, whereas it was restricted to a narrow pericentral rim in rats and showed a panlobular pattern in pigs. Similarly, CYP3A4 is present in the pericentral region, but its extent varies considerably in rats and appears panlobular in pigs. CYP2D6 zonal expression consistently shows a panlobular pattern in all species, although the intensity varies. CYP2E1 zonal expression covered the entire pericentral region with extension into the midzone in all four species, suggesting its potential for further cross-species analysis. Analysis of lobular geometry revealed an increase in lobular size with increasing species size, whereas lobular compactness was similar. Based on our results, zonated CYP expression in mice is most similar to humans. Therefore, mice appear to be the most appropriate species for drug metabolism studies unless larger species are required for other purposes, e.g., surgical reasons. CYP selection should be based on species, with CYP2E1 and CYP2D6 being the most preferable to compare four species. CYP1A2 could be considered as an additional CYP for rodent versus human comparisons, and CYP3A4 for mouse/human comparisons. In conclusion, our image analysis pipeline together with suggestions for species and CYP selection can serve to improve future cross-species and translational drug metabolism studies. [ABSTRACT FROM AUTHOR]

Endothelial cells (ECs) are highly glycolytic, but whether they generate glycolytic intermediates via gluconeogenesis (GNG) in glucose-deprived conditions remains unknown. Here, we report that glucose-deprived ECs upregulate the GNG enzyme PCK2 and rely on a PCK2-dependent truncated GNG, whereby lactate and glutamine are used for the synthesis of lower glycolytic intermediates that enter the serine and glycerophospholipid biosynthesis pathways, which can play key roles in redox homeostasis and phospholipid synthesis, respectively. Unexpectedly, however, even in normal glucose conditions, and independent of its enzymatic activity, PCK2 silencing perturbs proteostasis, beyond its traditional GNG role. Indeed, PCK2-silenced ECs have an impaired unfolded protein response, leading to accumulation of misfolded proteins, which due to defective proteasomes and impaired autophagy, results in the accumulation of protein aggregates in lysosomes and EC demise. Ultimately, loss of PCK2 in ECs impaired vessel sprouting. This study identifies a role for PCK2 in proteostasis beyond GNG. This study reports a unexpected role in endothelial cells (ECs) for PCK2 in proteostasis, independent of its gluconeogenic activity. Perturbation of this role likely contributed to the angiogenic defects observed in ECs with reduced PCK2 levels. [ABSTRACT FROM AUTHOR]

Nitrogen is one of the important factors restricting the development of sesame planting and industry in China. Cultivating sesame varieties tolerant to low nitrogen is an effective way to solve the problem of crop nitrogen deficiency. To date, the mechanism of low nitrogen tolerance in sesame has not been elucidated at the transcriptional level. In this study, two sesame varieties Zhengzhi HL05 (ZZ, nitrogen efficient) and Burmese prolific (MD, nitrogen inefficient) in low nitrogen were used for RNA-sequencing. A total of 3964 DEGs (differentially expressed genes) and 221 DELs (differentially expressed lncRNAs) were identified in two sesame varieties at 3d and 9d after low nitrogen stress. Among them, 1227 genes related to low nitrogen tolerance are mainly located in amino acid metabolism, starch and sucrose metabolism and secondary metabolism, and participate in the process of transporter activity and antioxidant activity. In addition, a total of 209 pairs of lncRNA-mRNA were detected, including 21 pairs of trans and 188 cis. WGCNA (weighted gene co-expression network analysis) analysis divided the obtained genes into 29 modules; phenotypic association analysis identified three low-nitrogen response modules; through lncRNA-mRNA co-expression network, a number of hub genes and cis/trans-regulatory factors were identified in response to low-nitrogen stress including GS1-2 (glutamine synthetase 1–2), PAL (phenylalanine ammonia-lyase), CHS (chalcone synthase, CHS), CAB21 (chlorophyll a-b binding protein 21) and transcription factors MYB54, MYB88 and NAC75 and so on. As a trans regulator, lncRNA MSTRG.13854.1 affects the expression of some genes related to low nitrogen response by regulating the expression of MYB54, thus responding to low nitrogen stress. Our research is the first to provide a more comprehensive understanding of DEGs involved in the low nitrogen stress of sesame at the transcriptome level. These results may reveal insights into the molecular mechanisms of low nitrogen tolerance in sesame and provide diverse genetic resources involved in low nitrogen tolerance research. [ABSTRACT FROM AUTHOR]

SUMMARY: CpcL‐phycobilisomes (CpcL‐PBSs) are a reduced type of phycobilisome (PBS) found in several cyanobacteria. They lack the traditional PBS terminal energy emitters, but still show the characteristic red‐shifted fluorescence at ~670 nm. We established a method of assembling in vitro a rod‐membrane linker protein, CpcL, with phycocyanin, generating complexes with the red‐shifted spectral features of CpcL‐PBSs. The red‐shift arises from the interaction of a conserved key glutamine, Q57 of CpcL in Synechocystis sp. PCC 6803, with a single phycocyanobilin chromophore of trimeric phycocyanin at one of the three β82‐sites. This chromophore is the terminal energy acceptor of CpcL‐PBSs and donor to the photosystem(s). This mechanism also operates in PBSs from Acaryochloris marina MBIC11017. We then generated multichromic complexes harvesting light over nearly the complete visible range via the replacement of phycocyanobilin chromophores at sites α84 and β153 of phycocyanins by phycoerythrobilin and/or phycourobilin. The results demonstrate the rational design of biliprotein‐based light‐harvesting elements by engineering CpcL and phycocyanins, which broadens the light‐harvesting range and accordingly improves the light‐harvesting capacity and may be potentially applied in solar energy harvesting. [ABSTRACT FROM AUTHOR]

Hairgrass (Deschampsia caespitosa), a widely distributed grass species considered promising in the ecological restoration of degraded grassland in the Qinghai-Xizang Plateau, is likely to be subjected to frequent drought and waterlogging stress due to ongoing climate change, further aggravating the degradation of grassland in this region. However, whether it would acclimate to water stresses resulting from extreme climates remains unknown. Proline accumulation is a crucial metabolic response of plants to challenging environmental conditions. This study aims to investigate the changes in proline accumulation and key enzymes in hairgrass shoot and root tissues in response to distinct climate extremes including moderate drought, moderate waterlogging, and dry–wet variations over 28 days using a completely randomized block design. The proline accumulation, contribution of the glutamate and ornithine pathways, and key enzyme activities related to proline metabolism in shoot and root tissues were examined. The results showed that water stress led to proline accumulation in both shoot and root tissues of hairgrass, highlighting the importance of this osmoprotectant in mitigating the effects of environmental challenges. The differential accumulation of proline in shoots compared to roots suggests a strategic allocation of resources by the plant to cope with osmotic stress. Enzymatic activities related to proline metabolism, such as Δ1-pyrroline-5-carboxylate synthetase, ornithine aminotransferase, Δ1-pyrroline-5-carboxylate reductase, Δ1-pyrroline-5-carboxylate dehydrogenase, and proline dehydrogenase, further emphasize the dynamic regulation of proline levels in hairgrass under water stress conditions. These findings support the potential for enhancing the stress resistance of hairgrass through the genetic manipulation of proline biosynthesis and catabolism pathways. [ABSTRACT FROM AUTHOR]

The gene products of PRS1-PRS5 in Saccharomyces cerevisiae are responsible for the production of PRPP (5-phospho-D-ribosyl-α-1-pyrophosphate). However, it has been demonstrated that they are also involved in the cell wall integrity (CWI) signalling pathway as shown by protein–protein interactions (PPIs) with, for example Slt2, the MAP kinase of the CWI pathway. The following databases: SGD, BioGRID and Hit Predict, which collate PPIs from various research papers, have been scrutinized for evidence of PPIs between Prs1-Prs5 and components of the CWI pathway. The level of certainty in PPIs was verified by interaction scores available in the Hit Predict database revealing that well-documented interactions correspond with higher interaction scores and can be graded as high confidence interactions based on a score > 0.28, an annotation score ≥ 0.5 and a method-based high confidence score level of ≥ 0.485. Each of the Prs1-Prs5 polypeptides shows some degree of interaction with the CWI pathway. However, Prs5 has a vital role in the expression of FKS2 and Rlm1, previously only documented by reporter assay studies. This report emphasizes the importance of investigating interactions using more than one approach since every method has its limitations and the use of different methods, as described herein, provides complementary experimental and statistical data, thereby corroborating PPIs. Since the experimental data described so far are consistent with a link between PRPP synthetase and the CWI pathway, our aim was to demonstrate that these data are also supported by high-throughput bioinformatic analyses promoting our hypothesis that two of the five PRS-encoding genes contain information required for the maintenance of CWI by combining data from our targeted approach with relevant, unbiased data from high-throughput analyses. [ABSTRACT FROM AUTHOR]

Background: Frailty is a multifaceted geriatric syndrome characterized by an increased vulnerability to stressful events. metabolomics studies are valuable tool for better understanding the underlying mechanisms of pathologic conditions. This review aimed to elucidate the metabolomics profile of frailty. Method: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) 2020 statement. A comprehensive search was conducted across multiple databases. Initially, 5027 results were retrieved, and after removing duplicates, 1838 unique studies were subjected to screening. Subsequently, 248 studies underwent full-text screening, with 21 studies ultimately included in the analysis. Data extraction was performed meticulously by two authors, and the quality of the selected studies was assessed using the Critical Appraisal Skills Program (CASP) checklist. Results: The findings revealed that certain Branched-chain amino acids (BCAAs) levels were lower in frail subjects compared to robust subjects, while levels of glutamate and glutamine were higher in frail individuals. Moreover, sphingomyelins and phosphatidylcholines (PC) displayed a decreasing trend as frailty advanced. Additionally, other metabolic derivatives, such as carnitine, exhibited significant associations with frailty. These metabolites were primarily interconnected through biochemical pathways related to the tricarboxylic acid and urea cycles. Notably, frailty was associated with a decrease in metabolic derivatives, including carnitine. Conclusion: This study underscores the intricate relationship between essential metabolites, including amino acids and lipids, and their varying levels in frail individuals compared to their robust counterparts. It provides a comprehensive panel of metabolites, shedding light on their potential associations with frailty and expanding our understanding of this complex syndrome. [ABSTRACT FROM AUTHOR]