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1.
Front Endocrinol (Lausanne) ; 15: 1382844, 2024.
Article in English | MEDLINE | ID: mdl-38689728

ABSTRACT

Equine metabolic syndrome (EMS) is a critical endocrine condition in horses, characterized by hyperinsulinemia, hyperlipidemia, and insulin resistance, posing a significant threat to their health. This study investigates the efficacy of supplementing EMS-affected horses with Arthrospira platensis enriched with Cr(III), Mg(II), and Mn(II) ions using biosorption process in improving insulin sensitivity and glucose tolerance, reducing inflammation, and mitigating obesity-related fat accumulation. Our results demonstrate that Arthrospira supplementation reduces baseline insulin and glucose levels, contributing to decreased adipose tissue inflammation. Furthermore, Arthrospira supplementation results in a decrease in body weight and improvements in overall body condition scores and cresty neck scores. Additionally, administration of Arthrospira leads to reduced levels of triglycerides and aspartate aminotransferase, indicating a decrease in hepatic adiposity and inflammation. These findings suggest that Arthrospira, enriched with essential micro- and macroelements, can be an advanced feed additive to enhance insulin sensitivity, promote weight reduction, and alleviate inflammatory processes, thereby improving the overall condition of horses affected by EMS. The use of Arthrospira as a feed additive has the potential to complement conventional management strategies for EMS.


Subject(s)
Animal Feed , Chromium , Dietary Supplements , Horse Diseases , Inflammation , Insulin Resistance , Magnesium , Manganese , Metabolic Syndrome , Spirulina , Animals , Horses , Inflammation/metabolism , Metabolic Syndrome/veterinary , Metabolic Syndrome/metabolism , Horse Diseases/metabolism , Horse Diseases/prevention & control , Animal Feed/analysis , Magnesium/metabolism , Male , Female
2.
Sci Rep ; 14(1): 10959, 2024 05 14.
Article in English | MEDLINE | ID: mdl-38745034

ABSTRACT

Molecular hydrogen is an emerging broad-spectrum antioxidant molecule that can be used to treat myocardial infarction (MI). However, with hydrogen inhalation, the concentration that can be reached within target organs is low and the duration of action is short, which makes it difficult to achieve high dose targeted delivery of hydrogen to the heart, seriously limiting the therapeutic potential of hydrogen for MI. As a result of reactions with the internal environment of the body, subcutaneous implantation of magnesium slices leads to continuous endogenous hydrogen production, leading to a higher hydrogen concentration and a longer duration of action in target organs. In this study, we propose magnesium implant-based hydrogen therapy for MI. After subcutaneous implantation of magnesium slices in the dorsum of rats, we measured hydrogen production and efficiency, and evaluated the safety of this approach. Compared with hydrogen inhalation, it significantly improved cardiac function in rats with MI. Magnesium implantation also cleared free radicals that were released as a result of mitochondrial dysfunction, as well as suppressing cardiomyocyte apoptosis.


Subject(s)
Hydrogen , Magnesium , Myocardial Infarction , Animals , Myocardial Infarction/drug therapy , Myocardial Infarction/metabolism , Magnesium/metabolism , Rats , Male , Rats, Sprague-Dawley , Apoptosis/drug effects , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/drug effects , Disease Models, Animal
3.
Nat Commun ; 15(1): 4115, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38750013

ABSTRACT

RyR1 is an intracellular Ca2+ channel important in excitable cells such as neurons and muscle fibers. Ca2+ activates it at low concentrations and inhibits it at high concentrations. Mg2+ is the main physiological RyR1 inhibitor, an effect that is overridden upon activation. Despite the significance of Mg2+-mediated inhibition, the molecular-level mechanisms remain unclear. In this work we determined two cryo-EM structures of RyR1 with Mg2+ up to 2.8 Å resolution, identifying multiple Mg2+ binding sites. Mg2+ inhibits at the known Ca2+ activating site and we propose that the EF hand domain is an inhibitory divalent cation sensor. Both divalent cations bind to ATP within a crevice, contributing to the precise transmission of allosteric changes within the enormous channel protein. Notably, Mg2+ inhibits RyR1 by interacting with the gating helices as validated by molecular dynamics. This structural insight enhances our understanding of how Mg2+ inhibition is overcome during excitation.


Subject(s)
Calcium , Cryoelectron Microscopy , Magnesium , Ryanodine Receptor Calcium Release Channel , Ryanodine Receptor Calcium Release Channel/metabolism , Ryanodine Receptor Calcium Release Channel/chemistry , Magnesium/metabolism , Calcium/metabolism , Binding Sites , Animals , Molecular Dynamics Simulation , Adenosine Triphosphate/metabolism , Humans , Rabbits
4.
Int J Mol Sci ; 25(9)2024 May 03.
Article in English | MEDLINE | ID: mdl-38732212

ABSTRACT

The skin wound healing process consists of hemostatic, inflammatory, proliferative, and maturation phases, with a complex cellular response by multiple cell types in the epidermis, dermis, and immune system. Magnesium is a mineral essential for life, and although magnesium treatment promotes cutaneous wound healing, the molecular mechanism and timing of action of the healing process are unknown. This study, using human epidermal-derived HaCaT cells and human normal epidermal keratinocyte cells, was performed to investigate the mechanism involved in the effect of magnesium on wound healing. The expression levels of epidermal differentiation-promoting factors were reduced by MgCl2, suggesting an inhibitory effect on epidermal differentiation in the remodeling stage of the late wound healing process. On the other hand, MgCl2 treatment increased the expression of matrix metalloproteinase-7 (MMP7), a cell migration-promoting factor, and enhanced cell migration via the MEK/ERK pathway activation. The enhancement of cell migration by MgCl2 was inhibited by MMP7 knockdown, suggesting that MgCl2 enhances cell migration which is mediated by increased MMP7 expression. Our results revealed that MgCl2 inhibits epidermal differentiation but promotes cell migration, suggesting that applying magnesium to the early wound healing process could be beneficial.


Subject(s)
Cell Differentiation , Cell Movement , Keratinocytes , Magnesium , Matrix Metalloproteinase 7 , Wound Healing , Wound Healing/drug effects , Humans , Cell Movement/drug effects , Keratinocytes/drug effects , Keratinocytes/metabolism , Cell Differentiation/drug effects , Magnesium/pharmacology , Magnesium/metabolism , Matrix Metalloproteinase 7/metabolism , Matrix Metalloproteinase 7/genetics , Skin/metabolism , Skin/drug effects , Skin/injuries , MAP Kinase Signaling System/drug effects , Cell Line , Epidermis/drug effects , Epidermis/metabolism , Magnesium Chloride/pharmacology
5.
Int J Mol Sci ; 25(9)2024 May 04.
Article in English | MEDLINE | ID: mdl-38732240

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) infection has rapidly spread through various routes. A genomic analysis of clinical MRSA samples revealed an unknown protein, Sav2152, predicted to be a haloacid dehalogenase (HAD)-like hydrolase, making it a potential candidate for a novel drug target. In this study, we determined the crystal structure of Sav2152, which consists of a C2-type cap domain and a core domain. The core domain contains four motifs involved in phosphatase activity that depend on the presence of Mg2+ ions. Specifically, residues D10, D12, and D233, which closely correspond to key residues in structurally homolog proteins, are responsible for binding to the metal ion and are known to play critical roles in phosphatase activity. Our findings indicate that the Mg2+ ion known to stabilize local regions surrounding it, however, paradoxically, destabilizes the local region. Through mutant screening, we identified D10 and D12 as crucial residues for metal binding and maintaining structural stability via various uncharacterized intra-protein interactions, respectively. Substituting D10 with Ala effectively prevents the interaction with Mg2+ ions. The mutation of D12 disrupts important structural associations mediated by D12, leading to a decrease in the stability of Sav2152 and an enhancement in binding affinity to Mg2+ ions. Additionally, our study revealed that D237 can replace D12 and retain phosphatase activity. In summary, our work uncovers the novel role of metal ions in HAD-like phosphatase activity.


Subject(s)
Bacterial Proteins , Hydrolases , Magnesium , Phosphoric Monoester Hydrolases , Magnesium/metabolism , Bacterial Proteins/metabolism , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Phosphoric Monoester Hydrolases/metabolism , Phosphoric Monoester Hydrolases/chemistry , Phosphoric Monoester Hydrolases/genetics , Hydrolases/metabolism , Hydrolases/chemistry , Hydrolases/genetics , Models, Molecular , Methicillin-Resistant Staphylococcus aureus/enzymology , Methicillin-Resistant Staphylococcus aureus/genetics , Staphylococcus aureus/enzymology , Crystallography, X-Ray , Protein Binding
6.
Cell Mol Life Sci ; 81(1): 213, 2024 May 10.
Article in English | MEDLINE | ID: mdl-38727814

ABSTRACT

Trimeric G proteins transduce signals from a superfamily of receptors and each G protein controls a wide range of cellular and systemic functions. Their highly conserved alpha subunits fall in five classes, four of which have been well investigated (Gs, Gi, G12, Gq). In contrast, the function of the fifth class, Gv is completely unknown, despite its broad occurrence and evolutionary ancient origin (older than metazoans). Here we show a dynamic presence of Gv mRNA in several organs during early development of zebrafish, including the hatching gland, the pronephros and several cartilage anlagen, employing in situ hybridisation. Next, we generated a Gv frameshift mutation in zebrafish and observed distinct phenotypes such as reduced oviposition, premature hatching and craniofacial abnormalities in bone and cartilage of larval zebrafish. These phenotypes could suggest a disturbance in ionic homeostasis as a common denominator. Indeed, we find reduced levels of calcium, magnesium and potassium in the larvae and changes in expression levels of the sodium potassium pump atp1a1a.5 and the sodium/calcium exchanger ncx1b in larvae and in the adult kidney, a major osmoregulatory organ. Additionally, expression of sodium chloride cotransporter slc12a3 and the anion exchanger slc26a4 is altered in complementary ways in adult kidney. It appears that Gv may modulate ionic homeostasis in zebrafish during development and in adults. Our results constitute the first insight into the function of the fifth class of G alpha proteins.


Subject(s)
Homeostasis , Zebrafish Proteins , Zebrafish , Animals , Zebrafish/genetics , Zebrafish/metabolism , Homeostasis/genetics , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism , GTP-Binding Protein alpha Subunits/metabolism , GTP-Binding Protein alpha Subunits/genetics , Larva/metabolism , Larva/genetics , Larva/growth & development , Gene Expression Regulation, Developmental , Sodium-Potassium-Exchanging ATPase/metabolism , Sodium-Potassium-Exchanging ATPase/genetics , Calcium/metabolism , Kidney/metabolism , Magnesium/metabolism
7.
Arch Insect Biochem Physiol ; 116(1): e22118, 2024 May.
Article in English | MEDLINE | ID: mdl-38713637

ABSTRACT

We detected enzymatic activity that generates 20-nucleotide (nt) RNA from double-stranded RNAs (dsRNAs) in crude extracts prepared from various silkworm (Bombyx mori) organs. The result using knocked-down cultured cells indicated that this dicing activity originated from B. mori Dicer-2 (BmDcr2). Biochemical analyses revealed that BmDcr2 preferentially cleaves 5'-phosphorylated dsRNAs at the 20-nt site-counted from the 5'-phosphorylated end-and required ATP and magnesium ions for the dicing reaction. This is the first report of the biochemical characterization of Dicer-2 in lepidopteran insects. This enzymatic property of BmDcr2 in vitro is consistent with the in vivo small interfering RNA profile in virus-infected silkworm cells.


Subject(s)
Bombyx , RNA, Double-Stranded , Ribonuclease III , Animals , Bombyx/genetics , Bombyx/metabolism , Insect Proteins/metabolism , Insect Proteins/genetics , Larva/metabolism , Larva/genetics , Larva/growth & development , Magnesium/metabolism , Ribonuclease III/metabolism , Ribonuclease III/genetics , RNA, Double-Stranded/metabolism , RNA, Small Interfering/metabolism
8.
Nat Commun ; 15(1): 4218, 2024 May 17.
Article in English | MEDLINE | ID: mdl-38760331

ABSTRACT

DNAzymes - synthetic enzymes made of DNA - have long attracted attention as RNA-targeting therapeutic agents. Yet, as of now, no DNAzyme-based drug has been approved, partially due to our lacking understanding of their molecular mode of action. In this work we report the solution structure of 8-17 DNAzyme bound to a Zn2+ ion solved through NMR spectroscopy. Surprisingly, it turned out to be very similar to the previously solved Pb2+-bound form (catalytic domain RMSD = 1.28 Å), despite a long-standing literature consensus that Pb2+ recruits a different DNAzyme fold than other metal ion cofactors. Our follow-up NMR investigations in the presence of other ions - Mg2+, Na+, and Pb2+ - suggest that at DNAzyme concentrations used in NMR all these ions induce a similar tertiary fold. Based on these findings, we propose a model for 8-17 DNAzyme interactions with metal ions postulating the existence of only a single catalytically-active structure, yet populated to a different extent depending on the metal ion cofactor. Our results provide structural information on the 8-17 DNAzyme in presence of non-Pb2+ cofactors, including the biologically relevant Mg2+ ion.


Subject(s)
DNA, Catalytic , Lead , Magnesium , Zinc , DNA, Catalytic/chemistry , DNA, Catalytic/metabolism , Magnesium/metabolism , Magnesium/chemistry , Zinc/metabolism , Zinc/chemistry , Lead/chemistry , Lead/metabolism , Nucleic Acid Conformation , Catalytic Domain , Models, Molecular , Sodium/metabolism , Sodium/chemistry , Metals/metabolism , Metals/chemistry , Magnetic Resonance Spectroscopy , Ions
9.
J Nanobiotechnology ; 22(1): 268, 2024 May 19.
Article in English | MEDLINE | ID: mdl-38764056

ABSTRACT

The development of cost-effective and eco-friendly fertilizers is crucial for enhancing iron (Fe) uptake in crops and can help alleviate dietary Fe deficiencies, especially in populations with limited access to meat. This study focused on the application of MgFe-layered double hydroxide nanoparticles (MgFe-LDHs) as a potential solution. We successfully synthesized and characterized MgFe-LDHs and observed that 1-10 mg/L MgFe-LDHs improved cucumber seed germination and water uptake. Notably, the application of 10 mg/L MgFe-LDHs to roots significantly increased the seedling emergence rate and growth under low-temperature stress. The application of 10 mg/L MgFe-LDHs during sowing increased the root length, lateral root number, root fresh weight, aboveground fresh weight, and hypocotyl length under low-temperature stress. A comprehensive analysis integrating plant physiology, nutrition, and transcriptomics suggested that MgFe-LDHs improve cold tolerance by upregulating SA to stimulate CsFAD3 expression, elevating GA3 levels for enhanced nitrogen metabolism and protein synthesis, and reducing levels of ABA and JA to support seedling emergence rate and growth, along with increasing the expression and activity of peroxidase genes. SEM and FTIR further confirmed the adsorption of MgFe-LDHs onto the root hairs in the mature zone of the root apex. Remarkably, MgFe-LDHs application led to a 46% increase (p < 0.05) in the Fe content within cucumber seedlings, a phenomenon not observed with comparable iron salt solutions, suggesting that the nanocrystalline nature of MgFe-LDHs enhances their absorption efficiency in plants. Additionally, MgFe-LDHs significantly increased the nitrogen (N) content of the seedlings by 12% (p < 0.05), promoting nitrogen fixation in the cucumber seedlings. These results pave the way for the development and use of LDH-based Fe fertilizers.


Subject(s)
Cold Temperature , Cucumis sativus , Iron , Seedlings , Cucumis sativus/growth & development , Cucumis sativus/metabolism , Cucumis sativus/drug effects , Seedlings/growth & development , Seedlings/metabolism , Seedlings/drug effects , Iron/metabolism , Plant Roots/metabolism , Plant Roots/growth & development , Germination/drug effects , Hydroxides/pharmacology , Hydroxides/metabolism , Fertilizers , Gene Expression Regulation, Plant/drug effects , Nanoparticles/chemistry , Stress, Physiological , Magnesium/metabolism
10.
Nutrients ; 16(10)2024 May 07.
Article in English | MEDLINE | ID: mdl-38794644

ABSTRACT

Endothelial dysfunction is a crucial event in the early pathogenesis of cardiovascular diseases and is linked to magnesium (Mg) deficiency. Indeed, in endothelial cells, low Mg levels promote the acquisition of a pro-inflammatory and pro-atherogenic phenotype. This paper investigates the mechanisms by which Mg deficiency promotes oxidative stress and affects endothelial behavior in human umbilical vascular endothelial cells (HUVECs). Our data show that low Mg levels trigger oxidative stress initially by increasing NAPDH oxidase activity and then by upregulating the pro-oxidant thioredoxin-interacting protein TXNIP. The overproduction of reactive oxygen species (ROS) activates NF-κB, leading to its increased binding to the inducible nitric oxide synthase (iNOS) promoter, with the consequent increase in iNOS expression. The increased levels of nitric oxide (NO) generated by upregulated iNOS contribute to disrupting endothelial cell function by inhibiting growth and increasing permeability. In conclusion, we provide evidence that multiple mechanisms contribute to generate a pro-oxidant state under low-Mg conditions, ultimately affecting endothelial physiology. These data add support to the notion that adequate Mg levels play a significant role in preserving cardiovascular health and may suggest new approaches to prevent or manage cardiovascular diseases.


Subject(s)
Human Umbilical Vein Endothelial Cells , Magnesium Deficiency , Magnesium , Nitric Oxide Synthase Type II , Nitric Oxide , Oxidative Stress , Reactive Oxygen Species , Humans , Nitric Oxide Synthase Type II/metabolism , Nitric Oxide Synthase Type II/genetics , Magnesium Deficiency/metabolism , Reactive Oxygen Species/metabolism , Nitric Oxide/metabolism , Magnesium/metabolism , NF-kappa B/metabolism , Carrier Proteins/metabolism , Carrier Proteins/genetics , Endothelium, Vascular/metabolism
11.
PLoS Biol ; 22(4): e3002560, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38574172

ABSTRACT

In all domains of life, Hsp70 chaperones preserve protein homeostasis by promoting protein folding and degradation and preventing protein aggregation. We now report that the Hsp70 from the bacterial pathogen Salmonella enterica serovar Typhimurium-termed DnaK-independently reduces protein synthesis in vitro and in S. Typhimurium facing cytoplasmic Mg2+ starvation, a condition encountered during infection. This reduction reflects a 3-fold increase in ribosome association with DnaK and a 30-fold decrease in ribosome association with trigger factor, the chaperone normally associated with translating ribosomes. Surprisingly, this reduction does not involve J-domain cochaperones, unlike previously known functions of DnaK. Removing the 74 C-terminal amino acids of the 638-residue long DnaK impeded DnaK association with ribosomes and reduction of protein synthesis, rendering S. Typhimurium defective in protein homeostasis during cytoplasmic Mg2+ starvation. DnaK-dependent reduction in protein synthesis is critical for survival against Mg2+ starvation because inhibiting protein synthesis in a dnaK-independent manner overcame the 10,000-fold loss in viability resulting from DnaK truncation. Our results indicate that DnaK protects bacteria from infection-relevant stresses by coordinating protein synthesis with protein folding capacity.


Subject(s)
Escherichia coli Proteins , Magnesium , Magnesium/metabolism , Escherichia coli Proteins/metabolism , Escherichia coli/metabolism , HSP70 Heat-Shock Proteins/metabolism , Molecular Chaperones/metabolism , Protein Folding , Bacteria/metabolism , Salmonella
12.
Nat Commun ; 15(1): 3406, 2024 Apr 22.
Article in English | MEDLINE | ID: mdl-38649706

ABSTRACT

Synapses at dendritic branches exhibit specific properties for information processing. However, how the synapses are orchestrated to dynamically modify their properties, thus optimizing information processing, remains elusive. Here, we observed at hippocampal dendritic branches diverse configurations of synaptic connectivity, two extremes of which are characterized by low transmission efficiency, high plasticity and coding capacity, or inversely. The former favors information encoding, pertinent to learning, while the latter prefers information storage, relevant to memory. Presynaptic intracellular Mg2+ crucially mediates the dynamic transition continuously between the two extreme configurations. Consequently, varying intracellular Mg2+ levels endow individual branches with diverse synaptic computations, thus modulating their ability to process information. Notably, elevating brain Mg2+ levels in aging animals restores synaptic configuration resembling that of young animals, coincident with improved learning and memory. These findings establish intracellular Mg2+ as a crucial factor reconfiguring synaptic connectivity at dendrites, thus optimizing their branch-specific properties in information processing.


Subject(s)
Dendrites , Hippocampus , Magnesium , Neuronal Plasticity , Synapses , Synaptic Transmission , Animals , Magnesium/metabolism , Synapses/physiology , Synapses/metabolism , Hippocampus/physiology , Hippocampus/metabolism , Neuronal Plasticity/physiology , Dendrites/physiology , Dendrites/metabolism , Synaptic Transmission/physiology , Male , Memory/physiology , Rats , Learning/physiology , Mice , Mice, Inbred C57BL
13.
Mitochondrion ; 76: 101877, 2024 May.
Article in English | MEDLINE | ID: mdl-38599304

ABSTRACT

Mitochondrial Ca2+ uptake is essential in regulating bioenergetics, cell death, and cytosolic Ca2+ transients. Mitochondrial Calcium Uniporter (MCU) mediates the mitochondrial Ca2+ uptake. Though MCU regulation by MICUs is unequivocally established, there needs to be more knowledge of whether divalent cations regulate MCU. Here, we set out to understand the mitochondrial matrix Mg2+-dependent regulation of MCU activity. We showed that decreased matrix [Mg2+] is associated with increased MCU activity and significantly prompted mitochondrial permeability transition pore opening. Our findings support the critical role of mMg2+ in regulating MCU activity.


Subject(s)
Calcium Channels , Calcium , Magnesium , Mitochondria , Calcium/metabolism , Magnesium/metabolism , Calcium Channels/metabolism , Mitochondria/metabolism , Humans , Cell Survival , Mitochondrial Proteins/metabolism
14.
J Bacteriol ; 206(5): e0008024, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38661374

ABSTRACT

The hypothesis was tested that a kinetical flow equilibrium of uptake and efflux reactions is responsible for balancing the cellular zinc content. The experiments were done with the metal-resistant bacterium Cupriavidus metallidurans. In pulse-chase experiments, the cells were loaded with radioactive 65Zn and chased with the 100-fold concentration of non-radioactive zinc chloride. In parallel, the cells were loaded with isotope-enriched stable 67Zn and chased with non-enriched zinc to differentiate between zinc pools in the cell. The experiments demonstrated the existence of a kinetical flow equilibrium, resulting in a constant turnover of cell-bound zinc ions. The absence of the metal-binding cytoplasmic components, polyphosphate and glutathione, metal uptake, and metal efflux systems influenced the flow equilibrium. The experiments also revealed that not all zinc uptake and efflux systems are known in C. metallidurans. Cultivation of the cells under zinc-replete, zinc-, and zinc-magnesium-starvation conditions influenced zinc import and export rates. Here, magnesium starvation had a stronger influence compared to zinc starvation. Other metal cations, especially cobalt, affected the cellular zinc pools and zinc export during the chase reaction. In summary, the experiments with 65Zn and 67Zn demonstrated a constant turnover of cell-bound zinc. This indicated that simultaneously occurring import and export reactions in combination with cytoplasmic metal-binding components resulted in a kinetical flow equilibrium that was responsible for the adjustment of the cellular zinc content. IMPORTANCE: Understanding the biochemical action of a single enzyme or transport protein is the pre-requisite to obtain insight into its cellular function but this is only one half of the coin. The other side concerns the question of how central metabolic functions of a cell emerge from the interplay of different proteins and other macromolecules. This paper demonstrates that a flow equilibrium of zinc uptake and efflux reactions is at the core of cellular zinc homeostasis and identifies the most important contributors to this flow equilibrium: the uptake and efflux systems and metal-binding components of the cytoplasm.


Subject(s)
Cupriavidus , Zinc , Cupriavidus/metabolism , Cupriavidus/genetics , Zinc/metabolism , Biological Transport , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Magnesium/metabolism , Kinetics
15.
Food Chem ; 448: 139185, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38574715

ABSTRACT

The impact of hydrogen (H2) producing magnesium (Mg) incorporation into minced beef meat (MBM) on the quality and safety of the product was investigated. The H2-producing Mg (H2-P-Mg)-incorporated MBMs were vacuumed (VP) and stored at 4 °C for 12 days. Other MBMs were vacuumed and gassed with H2 or N2. At the end of storage, the lowest browning index values were for H2 and H2-P-Mg samples. H2- PMg and VP methods generally decreased the counts of mesophilic and psychrotrophic bacteria and yeast molds and restricted the formation of thiobarbituric acid reactive substances and biogenic amines. Heat mapping, PCA, and multivariate analysis methods confirmed chemical analysis results. The volatile compounds were at their highest levels in the control samples at the end of storage, followed by H2, N2, H2-P-Mg, and VP samples. Using the H2-P-Mg method in MBM preparation could protect the quality characteristics and safety of the product during cold storage.


Subject(s)
Food Preservation , Food Storage , Hydrogen , Magnesium , Animals , Cattle , Hydrogen/metabolism , Hydrogen/analysis , Magnesium/analysis , Magnesium/metabolism , Food Preservation/methods , Cold Temperature , Meat Products/analysis , Meat Products/microbiology , Bacteria/metabolism , Bacteria/isolation & purification , Red Meat/analysis , Red Meat/microbiology
16.
World J Microbiol Biotechnol ; 40(6): 182, 2024 Apr 26.
Article in English | MEDLINE | ID: mdl-38668902

ABSTRACT

The effect of barium ions on the biomineralization of calcium and magnesium ions is often overlooked when utilizing microbial-induced carbonate precipitation technology for removing barium, calcium, and magnesium ions from oilfield wastewater. In this study, Bacillus licheniformis was used to bio-precipitate calcium, magnesium, and barium ions. The effects of barium ions on the physiological and biochemical characteristics of bacteria, as well as the components of extracellular polymers and mineral characteristics, were also studied in systems containing coexisting barium, calcium, and magnesium ions. The results show that the increasing concentrations of barium ions decreased pH, carbonic anhydrase activity, and concentrations of bicarbonate and carbonate ions, while it increased the contents of humic acids, proteins, polysaccharides, and DNA in extracellular polymers in the systems containing all three types of ions. With increasing concentrations of barium ions, the content of magnesium within magnesium-rich calcite and the size of minerals precipitated decreased, while the full width at half maximum of magnesium-rich calcite, the content of O-C=O and N-C=O, and the diversity of protein secondary structures in the minerals increased in systems containing all three coexisting ions. Barium ions does inhibit the precipitation of calcium and magnesium ions, but the immobilized bacteria can mitigate the inhibitory effect. The precipitation ratios of calcium, magnesium, and barium ions reached 81-94%, 68-82%, and 90-97%. This research provides insights into the formation of barium-enriched carbonate minerals and offers improvements for treating oilfield wastewater.


Subject(s)
Bacillus licheniformis , Barium , Biomineralization , Calcium , Magnesium , Magnesium/metabolism , Bacillus licheniformis/metabolism , Barium/metabolism , Calcium/metabolism , Wastewater/microbiology , Wastewater/chemistry , Hydrogen-Ion Concentration , Ions , Carbonic Anhydrases/metabolism , Calcium Carbonate/metabolism
17.
Plant Physiol Biochem ; 210: 108615, 2024 May.
Article in English | MEDLINE | ID: mdl-38631158

ABSTRACT

Magnesium is one of the essential nutrients for plant growth, and plays a pivotal role in plant development and metabolism. Soil magnesium deficiency is evident in citrus production, which ultimately leads to failure of normal plant growth and development, as well as decreased productivity. Citrus is mainly propagated by grafting, so it is necessary to fully understand the different regulatory mechanisms of rootstock and scion response to magnesium deficiency. Here, we characterized the differences in morphological alterations, physiological metabolism and differential gene expression between trifoliate orange rootstocks and lemon scions under normal and magnesium-deficient conditions, revealing the different responses of rootstocks and scions to magnesium deficiency. The transcriptomic data showed that differentially expressed genes were enriched in 14 and 4 metabolic pathways in leaves and roots, respectively, after magnesium deficiency treatment. And the magnesium transport-related genes MHX and MRS2 may respond to magnesium deficiency stress. In addition, magnesium deficiency may affect plant growth by affecting POD, SOD, and CAT enzyme activity, as well as altering the levels of hormones such as IAA, ABA, GA3, JA, and SA, and the expression of related responsive genes. In conclusion, our research suggests that the leaves of lemon grafted onto trifoliate orange were more significantly affected than the roots under magnesium-deficient conditions, further indicating that the metabolic imbalance of scion lemon leaves was more severe.


Subject(s)
Citrus , Gene Expression Regulation, Plant , Magnesium , Seedlings , Citrus/metabolism , Citrus/genetics , Seedlings/metabolism , Seedlings/genetics , Seedlings/growth & development , Magnesium/metabolism , Plant Roots/metabolism , Plant Roots/growth & development , Plant Roots/genetics , Magnesium Deficiency/metabolism , Plant Leaves/metabolism , Stress, Physiological , Plant Growth Regulators/metabolism , Plant Proteins/metabolism , Plant Proteins/genetics
18.
mSystems ; 9(4): e0136823, 2024 Apr 16.
Article in English | MEDLINE | ID: mdl-38493407

ABSTRACT

Streptomyces bacteria are renowned both for their antibiotic production capabilities and for their cryptic metabolic potential. Their metabolic repertoire is subject to stringent genetic control, with many of the associated biosynthetic gene clusters being repressed by the conserved nucleoid-associated protein Lsr2. In an effort to stimulate new antibiotic production in wild Streptomyces isolates, we leveraged the activity of an Lsr2 knockdown construct and successfully enhanced antibiotic production in the wild Streptomyces isolate WAC07094. We determined that this new activity stemmed from increased levels of the angucycline-like family member saquayamycin. Saquayamycin has both antibiotic and anti-cancer activities, and intriguingly, beyond Lsr2-mediated repression, we found saquayamycin production was also suppressed at high density on solid or in liquid growth media; its levels were greatest in low-density cultures. This density-dependent control was exerted at the level of the cluster-situated regulatory gene sqnR and was mediated in part through the activity of the PhoRP two-component regulatory system, where deleting phoRP led to both constitutive antibiotic production and sqnR expression. This suggests that PhoP functions to repress the expression of sqnR at high cell density. We further discovered that magnesium supplementation could alleviate this density dependence, although its action was independent of PhoP. Finally, we revealed that the nitrogen-responsive regulators GlnR and AfsQ1 could relieve the repression exerted by Lsr2 and PhoP. Intriguingly, we found that this low density-dependent production of saquayamycin was not unique to WAC07094; saquayamycin production by another wild isolate also exhibited low-density activation, suggesting that this spatial control may serve an important ecological function in their native environments.IMPORTANCEStreptomyces specialized metabolic gene clusters are subject to complex regulation, and their products are frequently not observed under standard laboratory growth conditions. For the wild Streptomyces isolate WAC07094, production of the angucycline-family compound saquayamycin is subject to a unique constellation of control factors. Notably, it is produced primarily at low cell density, in contrast to the high cell density production typical of most antibiotics. This unusual density dependence is conserved in other saquayamycin producers and is driven by the pathway-specific regulator SqnR, whose expression is influenced by both nutritional and genetic elements. Collectively, this work provides new insights into an intricate regulatory system governing antibiotic production and indicates there may be benefits to including low-density cultures in antibiotic screening platforms.


Subject(s)
Anti-Bacterial Agents , Streptomyces , Anti-Bacterial Agents/pharmacology , Streptomyces/genetics , Angucyclines and Angucyclinones , Magnesium/metabolism , Gene Expression Regulation, Bacterial , Anthraquinones
19.
Biomed Mater ; 19(3)2024 Apr 11.
Article in English | MEDLINE | ID: mdl-38518370

ABSTRACT

In bone tissue engineering, the bone immunomodulatory properties of biomaterials are critical for bone regeneration, which is a synergistic process involving physiological activities like immune response, osteogenesis, and angiogenesis. The effect of the macrophage immune microenvironment on the osteogenesis and angiogenesis of various material extracts was examined in this experiment using Mg2+and Nano-hydroxyapatite/collagen (nHAC) in both a single application and a combined form. This studyin vitrorevealed that the two compounds combined significantly inhibited the NF-κB signaling pathway and reduced the release of inflammatory factors from macrophages when compared with the extraction phase alone. Additionally, by contributing to the polarization of macrophages towards the M2 type, the combined effects of the two materials can significantly improve osteogenesis/angiogenesis. The results ofin vivoexperiments confirmed that Mg2+/nHAC significantly promoted bone regeneration and angiogenesis. This study offers a promising method for enhancing bone graft material osseointegration.


Subject(s)
Magnesium , Osteogenesis , Magnesium/metabolism , Angiogenesis , Bone Regeneration , Collagen/metabolism , Macrophages/metabolism , Ions
20.
Microbiol Spectr ; 12(4): e0227823, 2024 Apr 02.
Article in English | MEDLINE | ID: mdl-38440972

ABSTRACT

Candida auris is frequently associated with biofilm-related invasive infections. The resistant profile of these biofilms necessitates innovative therapeutic options, where quorum sensing may be a potential target. Farnesol and tyrosol are two fungal quorum-sensing molecules with antifungal effects at supraphysiological concentrations. Here, we performed genome-wide transcript profiling with C. auris biofilms following farnesol or tyrosol exposure using transcriptome sequencing (RNA-Seq). Since transition metals play a central role in fungal virulence and biofilm formation, levels of intracellular calcium, magnesium, and iron were determined following farnesol or tyrosol treatment using inductively coupled plasma optical emission spectrometry. Farnesol caused an 89.9% and 73.8% significant reduction in the calcium and magnesium content, respectively, whereas tyrosol resulted in 82.6%, 76.6%, and 81.2% decrease in the calcium, magnesium, and iron content, respectively, compared to the control. Genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy were primarily affected in treated cells. To prove ergosterol quorum-sensing molecule interactions, microdilution-based susceptibility testing was performed, where the complexation of farnesol, but not tyrosol, with ergosterol was impeded in the presence of exogenous ergosterol, resulting in a minimum inhibitory concentration increase in the quorum-sensing molecules. This study revealed several farnesol- and tyrosol-specific responses, which will contribute to the development of alternative therapies against C. auris biofilms. IMPORTANCE: Candida auris is a multidrug-resistant fungal pathogen, which is frequently associated with biofilm-related infections. Candida-derived quorum-sensing molecules (farnesol and tyrosol) play a pivotal role in the regulation of fungal morphogenesis and biofilm development. Furthermore, they may have remarkable anti-biofilm effects, especially at supraphysiological concentrations. Innovative therapeutic approaches interfering with quorum sensing may be a promising future strategy against C. auris biofilms; however, limited data are currently available concerning farnesol-induced and tyrosol-related molecular effects in C. auris. Here, we detected several genes involved in biofilm events, glycolysis, ergosterol biosynthesis, fatty acid oxidation, iron metabolism, and autophagy, which were primarily influenced following farnesol or tyrosol exposure. Moreover, calcium, magnesium, and iron homeostasis were also significantly affected. These results reveal those molecular and physiological events, which may support the development of novel therapeutic approaches against C. auris biofilms.


Subject(s)
Candida auris , Farnesol , Phenylethyl Alcohol/analogs & derivatives , Farnesol/pharmacology , Farnesol/metabolism , Calcium/metabolism , Calcium/pharmacology , Magnesium/metabolism , Magnesium/pharmacology , Biofilms , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Antifungal Agents/metabolism , Ergosterol , Iron/metabolism , Fatty Acids/metabolism , Candida albicans , Microbial Sensitivity Tests
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