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Plant Physiology Aug 2022Leaf senescence can be induced by stress or aging, sometimes in a synergistic manner. It is generally acknowledged that the ability to withstand senescence-inducing...
Leaf senescence can be induced by stress or aging, sometimes in a synergistic manner. It is generally acknowledged that the ability to withstand senescence-inducing conditions can provide plants with stress resilience. Although the signaling and transcriptional networks responsible for a delayed senescence phenotype, often referred to as a functional stay-green trait, have been actively investigated, very little is known about the subsequent metabolic adjustments conferring this aptitude to survival. First, using the individually darkened leaf (IDL) experimental setup, we compared IDLs of wild-type (WT) Arabidopsis (Arabidopsis thaliana) to several stay-green contexts, that is IDLs of two functional stay-green mutant lines, oresara1-2 (ore1-2) and an allele of phytochrome-interacting factor 5 (pif5), as well as to leaves from a WT plant entirely darkened (DP). We provide compelling evidence that arginine and ornithine, which accumulate in all stay-green contexts-likely due to the lack of induction of amino acids (AAs) transport-can delay the progression of senescence by fueling the Krebs cycle or the production of polyamines (PAs). Secondly, we show that the conversion of putrescine to spermidine (SPD) is controlled in an age-dependent manner. Thirdly, we demonstrate that SPD represses senescence via interference with ethylene signaling by stabilizing the ETHYLENE BINDING FACTOR1 and 2 (EBF1/2) complex. Taken together, our results identify arginine and ornithine as central metabolites influencing the stress- and age-dependent progression of leaf senescence. We propose that the regulatory loop between the pace of the AA export and the progression of leaf senescence provides the plant with a mechanism to fine-tune the induction of cell death in leaves, which, if triggered unnecessarily, can impede nutrient remobilization and thus plant growth and survival.
Topics: Arabidopsis; Arabidopsis Proteins; Arginine; Ethylenes; Gene Expression Regulation, Plant; Ornithine; Plant Leaves; Plant Senescence; Transcription Factors
PubMed: 35604104
DOI: 10.1093/plphys/kiac244 -
Microbiome Nov 2023Minimizing mortality losses due to multiple stress and obtaining maximum performance are the production goals for newly received cattle. In recent years, vaccination and...
Revealing the developmental characterization of rumen microbiome and its host in newly received cattle during receiving period contributes to formulating precise nutritional strategies.
BACKGROUND
Minimizing mortality losses due to multiple stress and obtaining maximum performance are the production goals for newly received cattle. In recent years, vaccination and metaphylaxis treatment significantly decreased the mortality rate of newly received cattle, while the growth block induced by treatment is still obvious. Assessment of blood metabolites and behavior monitoring offer potential for early identification of morbid animals. Moreover, the ruminal microorganisms' homeostasis is a guarantee of beef steers' growth and health. The most critical period for newly received cattle is the first-month post-transport. Therefore, analyzing rumen metagenomics, rumen metabolomics, host metabolomics, and their interaction during receiving period (1 day before transport and at days 1/4, 16, and 30 after transport) is key to revealing the mechanism of growth retardation, and then to formulating management and nutritional practices for newly received cattle.
RESULTS
The levels of serum hormones (COR and ACTH), and pro-inflammatory factors (IL-1β, TNF-α, and IL-6) were highest at day 16, and lowest at day 30 after arrival. Meanwhile, the antioxidant capacity (SOD, GSH-Px, and T-AOC) was significantly decreased at day 16 and increased at day 30 after arrival. Metagenomics analysis revealed that rumen microbes, bacteria, archaea, and eukaryota had different trends among the four different time points. At day 16 post-transport, cattle had a higher abundance of ruminal bacteria and archaea than those before transport, but the eukaryote abundance was highest at day 30 post-transport. Before transport, most bacteria were mainly involved in polysaccharides digestion. At day 4 post-transport, the most significantly enriched KEGG pathways were nucleotide metabolism (pyrimidine metabolism and purine metabolism). At day 16 post-transport, the energy metabolism (glycolysis/gluconeogenesis, pyruvate metabolism) and ruminal contents of MCP and VFAs were significantly increased, but at the same time, energy loss induced by methane yields (Methanobrevibacter) together with pathogenic bacteria (Saccharopolyspora rectivirgula) were also significantly increased. At this time, the most upregulated ruminal L-ornithine produces more catabolite polyamines, which cause oxidative stress to rumen microbes and their host; the most downregulated ruminal 2',3'-cAMP provided favorable growth conditions for pathogenic bacteria, and the downregulated ruminal vitamin B6 metabolism and serum PC/LysoPC disrupt immune function and inflammation reaction. At day 30 post-transport, the ruminal L-ornithine and its catabolites (mainly spermidine and 1,3-propanediamine) were decreased, and the serum PC/LysoPC and 2',3'-cNMPs pools were increased. This is also consistent with the changes in redox, inflammation, and immune status of the host.
CONCLUSIONS
This study provides new ideas for regulating the health and performance of newly received cattle during the receiving period. The key point is to manage the newly received cattle about day 16 post-transport, specifically to inhibit the production of methane and polyamines, and the reproduction of harmful bacteria in the rumen, therefore improving the immunity and performance of newly received cattle. Video Abstract.
Topics: Cattle; Animals; Diet; Rumen; Microbiota; Bacteria; Archaea; Inflammation; Methane; Ornithine; Polyamines; Animal Feed; Fermentation
PubMed: 37924150
DOI: 10.1186/s40168-023-01682-z -
International Journal of Molecular... Aug 2023In this study, bipolar membrane electrodialysis was proposed to directly convert L-ornithine monohydrochloride to L-ornithine. The stack configuration was optimized in...
In this study, bipolar membrane electrodialysis was proposed to directly convert L-ornithine monohydrochloride to L-ornithine. The stack configuration was optimized in the BP-A (BP, bipolar membrane; A, anion exchange membrane) configuration with the Cl ion migration through the anion exchange membrane rather than the BP-A-C (C, cation exchange membrane) and the BP-C configurations with the L-ornithine ion migration through the cation exchange membrane. Both the conversion ratio and current efficiency follow BP-A > BP-A-C > BP-C, and the energy consumption follows BP-A < BP-A-C < BP-C. Additionally, the voltage drop across the membrane stack (two repeating units) and the feed concentration were optimized as 7.5 V and 0.50 mol/L, respectively, due to the low value of the sum of H ions leakage (from the acid compartment to the base compartment) and OH ions migration (from the base compartment to the acid compartment) through the anion exchange membrane. As a result, high conversion ratio (96.1%), high current efficiency (95.5%) and low energy consumption (0.31 kWh/kg L-ornithine) can be achieved. Therefore, bipolar membrane electrodialysis is an efficient, low energy consumption and environmentally friendly method to directly convert L-ornithine monohydrochloride to L-ornithine.
Topics: Membranes; Endoplasmic Reticulum; Ornithine
PubMed: 37685982
DOI: 10.3390/ijms241713174 -
MicrobiologyOpen Apr 2024Arginine-ornithine metabolism plays a crucial role in bacterial homeostasis, as evidenced by numerous studies. However, the utilization of arginine and the downstream...
Arginine-ornithine metabolism plays a crucial role in bacterial homeostasis, as evidenced by numerous studies. However, the utilization of arginine and the downstream products of its metabolism remain undefined in various gut bacteria. To bridge this knowledge gap, we employed genomic screening to pinpoint relevant metabolic targets. We also devised a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) metabolomics method to measure the levels of arginine, its upstream precursors, and downstream products in cell-free conditioned media from enteric pathobionts, including Escherichia coli, Klebsiella aerogenes, K. pneumoniae, Pseudomonas fluorescens, Acinetobacter baumannii, Streptococcus agalactiae, Staphylococcus epidermidis, S. aureus, and Enterococcus faecalis. Our findings revealed that all selected bacterial strains consumed glutamine, glutamate, and arginine, and produced citrulline, ornithine, and GABA in our chemically defined medium. Additionally, E. coli, K. pneumoniae, K. aerogenes, and P. fluorescens were found to convert arginine to agmatine and produce putrescine. Interestingly, arginine supplementation promoted biofilm formation in K. pneumoniae, while ornithine supplementation enhanced biofilm formation in S. epidermidis. These findings offer a comprehensive insight into arginine-ornithine metabolism in enteric pathobionts.
Topics: Ornithine; Putrescine; Arginine; Escherichia coli; Chromatography, Liquid; Staphylococcus aureus; Tandem Mass Spectrometry; Bacteria; Klebsiella pneumoniae
PubMed: 38560776
DOI: 10.1002/mbo3.1408 -
Translational Psychiatry Aug 2016Previous research implicates altered metabolism of l-arginine, a versatile amino acid with a number of bioactive metabolites, in the pathogenesis of schizophrenia. The...
Previous research implicates altered metabolism of l-arginine, a versatile amino acid with a number of bioactive metabolites, in the pathogenesis of schizophrenia. The present study, for we believe the first time, systematically compared the metabolic profile of l-arginine in the frontal cortex (Brodmann's area 8) obtained post-mortem from schizophrenic individuals and age- and gender-matched non-psychiatric controls (n=20 per group). The enzyme assays revealed no change in total nitric oxide synthase (NOS) activity, but significantly increased arginase activity in the schizophrenia group. Western blot showed reduced endothelial NOS protein expression and increased arginase II protein level in the disease group. High-performance liquid chromatography and liquid chromatography/mass spectrometric assays confirmed significantly reduced levels of γ-aminobutyric acid (GABA), but increased agmatine concentration and glutamate/GABA ratio in the schizophrenia cases. Regression analysis indicated positive correlations between arginase activity and the age of disease onset and between l-ornithine level and the duration of illness. Moreover, cluster analyses revealed that l-arginine and its main metabolites l-citrulline, l-ornithine and agmatine formed distinct groups, which were altered in the schizophrenia group. The present study provides further evidence of altered brain arginine metabolism in schizophrenia, which enhances our understanding of the pathogenesis of schizophrenia and may lead to the future development of novel preventions and/or therapeutics for the disease.
Topics: Agmatine; Arginase; Arginine; Autopsy; Blotting, Western; Brain; Case-Control Studies; Chromatography, High Pressure Liquid; Chromatography, Liquid; Citrulline; Female; Frontal Lobe; Glutamic Acid; Humans; Male; Mass Spectrometry; Middle Aged; Nitric Oxide Synthase Type III; Ornithine; Regression Analysis; Schizophrenia; gamma-Aminobutyric Acid
PubMed: 27529679
DOI: 10.1038/tp.2016.144 -
MBio Jun 2022Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor....
Previous studies have found that arginine biosynthesis in Staphylococcus aureus is repressed via carbon catabolite repression (CcpA), and proline is used as a precursor. Unexpectedly, however, robust growth of S. aureus is not observed in complete defined medium lacking both glucose and arginine (CDM-R). Mutants able to grow on agar-containing defined medium lacking arginine (CDM-R) were selected and found to contain mutations within , encoding the canonical arginine biosynthesis pathway repressor (AhrC), or single nucleotide polymorphisms (SNPs) upstream of the native arginine deiminase (ADI) operon . Reverse transcription-PCR (RT-PCR) studies found that mutations within or or SNPs identified upstream of increased the transcription of both and , encoding ornithine carbamoyltransferase and argininosuccinate synthase/lyase, respectively, facilitating arginine biosynthesis. Furthermore, mutations within the AhrC homologue facilitated robust growth within CDM-R. Complementation with or , but not , rescued growth in CDM-R. Finally, supplementation of CDM-R with ornithine stimulated growth, as did mutations in genes ( and ) that presumably increased the pyrroline-5-carboxylate and ornithine pools. Collectively, these data suggest that the transcriptional regulation of ornithine carbamoyltransferase and, in addition, the availability of intracellular ornithine pools regulate arginine biosynthesis in S. aureus in the absence of glucose. Surprisingly, ~50% of clinical S. aureus isolates were able to grow in CDM-R. These data suggest that S. aureus is selected to repress arginine biosynthesis in environments with or without glucose; however, mutants may be readily selected that facilitate arginine biosynthesis and growth in specific environments lacking arginine. Staphylococcus aureus can cause infection in virtually any niche of the human host, suggesting that it has significant metabolic versatility. Indeed, bioinformatic analysis suggests that it has the biosynthetic capability to synthesize all 20 amino acids. Paradoxically, however, it is conditionally auxotrophic for several amino acids, including arginine. Studies in our laboratory are designed to assess the biological function of amino acid auxotrophy in this significant pathogen. This study reveals that the metabolic block repressing arginine biosynthesis in media lacking glucose is the transcriptional repression of ornithine carbamoyltransferase encoded by within the native arginine deiminase operon in addition to limited intracellular pools of ornithine. Surprisingly, approximately 50% of S. aureus clinical isolates can grow in media lacking arginine, suggesting that mutations are selected in S. aureus that allow growth in particular niches of the human host.
Topics: Amino Acids; Arginine; Bacterial Proteins; Glucose; Ornithine; Ornithine Carbamoyltransferase; Staphylococcus aureus
PubMed: 35475645
DOI: 10.1128/mbio.00395-22 -
Current Drug Targets 2015Human proteins are subjected to more than 200 known post-translational modifications (PTMs) (e.g., phosphorylation, glycosylation, ubiquitination, S-nitrosylation,... (Review)
Review
Human proteins are subjected to more than 200 known post-translational modifications (PTMs) (e.g., phosphorylation, glycosylation, ubiquitination, S-nitrosylation, methylation, Nacetylation, and citrullination) and these PTMs can alter protein structure and function with consequent effects on the multitude of pathways necessary for maintaining the physiological homeostasis. When dysregulated, however, the enzymes that catalyze these PTMs can impact the genesis of countless diseases. In this review, we will focus on protein citrullination, a PTM catalyzed by the Protein Arginine Deiminase (PAD) family of enzymes. Specifically, we will describe the roles of the PADs in both normal human physiology and disease. The development of PAD inhibitors and their efficacy in a variety of autoimmune disorders and cancer will also be discussed.
Topics: Animals; Apoptosis; Arthritis, Rheumatoid; Citrulline; Humans; Hydrolases; Ornithine; Protein Processing, Post-Translational; Protein-Arginine Deiminases; Psoriasis
PubMed: 25642720
DOI: 10.2174/1389450116666150202160954 -
Scientific Reports Mar 2018This work reports a Lactobacillus rossiae strain (L. rossiae D87) isolated from sourdough that synthesizes putrescine - a biogenic amine that raises food safety and...
This work reports a Lactobacillus rossiae strain (L. rossiae D87) isolated from sourdough that synthesizes putrescine - a biogenic amine that raises food safety and spoilage concerns - from arginine via the ornithine decarboxylase (ODC) pathway. The odc and potE genes were identified and sequenced. These genes respectively encode ornithine decarboxylase (Odc), which participates in the decarboxylation of ornithine to putrescine, and the ornithine/putrescine exchanger (PotE), which exchanges ornithine for putrescine. Transcriptional analysis showed that odc and potE form an operon that is regulated transcriptionally by ornithine in a dose-dependent manner. To explore the possible role of the ODC pathway as an acid stress resistance mechanism for this bacterium, the effect of acidic pHs on its transcriptional regulation and on putrescine biosynthesis was analysed. Acidic pHs induced the transcription of the odc-potE genes and the production of putrescine over that seen at neutral pH. Further, putrescine production via the ODC system improved the survival of L. rossiae D87 by counteracting the acidification of the cytoplasm when the cells were subjected to acidic conditions. These results suggest the ODC pathway of L. rossiae D87 provides a biochemical defence mechanism against acidic environments.
Topics: Arginine; Bacterial Proteins; Bread; Gene Expression Regulation, Bacterial; Hydrogen-Ion Concentration; Lactobacillus; Multigene Family; Operon; Ornithine; Ornithine Decarboxylase; Phylogeny; Putrescine
PubMed: 29507315
DOI: 10.1038/s41598-018-22309-6 -
European Journal of Human Genetics :... Jul 2020
Topics: Genetic Testing; Humans; Hyperammonemia; Mitochondrial Membrane Transport Proteins; Mutation; Ornithine; Phenotype; Sensitivity and Specificity; Urea Cycle Disorders, Inborn
PubMed: 32242103
DOI: 10.1038/s41431-020-0616-x -
Computers in Biology and Medicine Jul 2022To implement and evaluate machine learning (ML) algorithms for the prediction of COVID-19 diagnosis, severity, and fatality and to assess biomarkers potentially...
OBJECTIVE
To implement and evaluate machine learning (ML) algorithms for the prediction of COVID-19 diagnosis, severity, and fatality and to assess biomarkers potentially associated with these outcomes.
MATERIAL AND METHODS
Serum (n = 96) and plasma (n = 96) samples from patients with COVID-19 (acute, severe and fatal illness) from two independent hospitals in China were analyzed by LC-MS. Samples from healthy volunteers and from patients with pneumonia caused by other viruses (i.e. negative RT-PCR for COVID-19) were used as controls. Seven different ML-based models were built: PLS-DA, ANNDA, XGBoostDA, SIMCA, SVM, LREG and KNN.
RESULTS
The PLS-DA model presented the best performance for both datasets, with accuracy rates to predict the diagnosis, severity and fatality of COVID-19 of 93%, 94% and 97%, respectively. Low levels of the metabolites ribothymidine, 4-hydroxyphenylacetoylcarnitine and uridine were associated with COVID-19 positivity, whereas high levels of N-acetyl-glucosamine-1-phosphate, cysteinylglycine, methyl isobutyrate, l-ornithine and 5,6-dihydro-5-methyluracil were significantly related to greater severity and fatality from COVID-19.
CONCLUSION
The PLS-DA model can help to predict SARS-CoV-2 diagnosis, severity and fatality in daily practice. Some biomarkers typically increased in COVID-19 patients' serum or plasma (i.e. ribothymidine, N-acetyl-glucosamine-1-phosphate, l-ornithine, 5,6-dihydro-5-methyluracil) should be further evaluated as prognostic indicators of the disease.
Topics: Biomarkers; COVID-19; COVID-19 Testing; Chromatography, Liquid; Glucosamine; Humans; Machine Learning; Ornithine; Phosphates; SARS-CoV-2; Tandem Mass Spectrometry; Thymine
PubMed: 35751188
DOI: 10.1016/j.compbiomed.2022.105659