High Ca2 Research Articles

Selenium and salt interactions in sage (Salvia officinalis L.): Growth and yield, chemical content, ion uptake

Salinity (NaCl) is a major abiotic stress that limits crop production, especially under rainfed conditions. Selenium (Se), as an important micronutrient, plays a vital role in mitigating the detrimental effects of different abiotic stresses. The objective of this research was to examine the effect of Se fertilization on sage (Salvia officinalis L.) under different salt stresses. The results showed that Se treatments caused significant improvements in the dry weight (DW) of sage under salt stress. It was found that the DW was increased in the combined treatment of 10 ppm of Se and 100 mM/L of NaCl and was reduced at the highest level of NaCl (100 mM/L). The highest essential oil percentages were recorded in the first harvest (5 ppm of Se), and the control treatment in the second and third harvests but significantly affected the low and high NaCl levels in the sage. Additionally, the results in this study showed that the application of Se from 2.5 ppm to 10 ppm significantly increased the essential oil components when under salt stress. The results showed that 5 ppm of Se and 50 mM/L of NaCl increased SO42− and PO43− concentrations in the first and third harvests. In addition, significant increases in K+ uptakes and decreases in Na+ uptakes were detected when the Se was added while the sage was under salt stress, and the highest Ca2+ and Mg2+ concentrations were all found in the Se treatments as well as in the combined treatments of Se and NaCl.

Trinuclear Calcium Site in the C2 Domain of PKCα/γ Is Prone to Lithium Attack.

Lithium (Li+) is the first-line therapy for bipolar disorder and a candidate drug for various diseases such as amyotrophic lateral sclerosis, multiple sclerosis, and stroke. Despite being the captivating subject of many studies, the mechanism of lithium’s therapeutic action remains unclear. To date, it has been shown that Li+ competes with Mg2+ and Na+ to normalize the activity of inositol and neurotransmitter-related signaling proteins, respectively. Furthermore, Li+ may co-bind with Mg2+-loaded adenosine or guanosine triphosphate to alter the complex’s susceptibility to hydrolysis and mediate cellular signaling. Bipolar disorder patients exhibit abnormally high cytosolic Ca2+ levels and protein kinase C (PKC) hyperactivity that can be downregulated by long-term Li+ treatment. However, the possibility that monovalent Li+ could displace the bulkier divalent Ca2+ and inhibit PKC activity has not been considered. Here, using density functional theory calculations combined with continuum dielectric methods, we show that Li+ may displace the native dication from the positively charged trinuclear site in the C2 domain of cytosolic PKCα/γ. This would affect the membrane-docking ability of cytosolic PKCα/γ and reduce the abnormally high membrane-associated active PKCα/γ levels, thus downregulating the PKC hyperactivity found in bipolar patients.

Pathological Mechanism of a Constitutively Active Form of Stromal Interaction Molecule 1 in Skeletal Muscle.

Stromal interaction molecule 1 (STIM1) is the main protein that, along with Orai1, mediates store-operated Ca2+ entry (SOCE) in skeletal muscle. Abnormal SOCE due to mutations in STIM1 is one of the causes of human skeletal muscle diseases. STIM1-R304Q (a constitutively active form of STIM1) has been found in human patients with skeletal muscle phenotypes such as muscle weakness, myalgia, muscle stiffness, and contracture. However, the pathological mechanism(s) of STIM1-R304Q in skeletal muscle have not been well studied. To examine the pathological mechanism(s) of STIM1-R304Q in skeletal muscle, STIM1-R304Q was expressed in mouse primary skeletal myotubes, and the properties of the skeletal myotubes were examined using single-myotube Ca2+ imaging, transmission electron microscopy (TEM), and biochemical approaches. STIM1-R304Q did not interfere with the terminal differentiation of skeletal myoblasts to myotubes and retained the ability of STIM1 to attenuate dihydropyridine receptor (DHPR) activity. STIM1-R304Q induced hyper-SOCE (that exceeded the SOCE by wild-type STIM1) by affecting both the amplitude and the onset rate of SOCE. Unlike that by wild-type STIM1, hyper-SOCE by STIM1-R304Q contributed to a disturbance in Ca2+ distribution between the cytosol and the sarcoplasmic reticulum (SR) (high Ca2+ in the cytosol and low Ca2+ in the SR). Moreover, the hyper-SOCE and the high cytosolic Ca2+ level induced by STIM1-R304Q involve changes in mitochondrial shape. Therefore, a series of these cellular defects induced by STIM1-R304Q could induce deleterious skeletal muscle phenotypes in human patients carrying STIM1-R304Q.

Progressively released gases from fluid inclusions reveal new insights on W-Sn mineralization of the Yaogangxian tungsten deposit, South China

The gentle stepwise crushing technique permits progressive extraction of gases from large, irregular, secondary fluid inclusions (SFIs) along micro-cracks to small, regular, liquid-rich primary fluid inclusions (PFIs). Previous studies have verified this general gas release pattern in different hydrothermal minerals based on the agreements between 40Ar/39Ar ages of the released gases from different crushing stages and the most likely corresponding geological events dated with other methods; and based on the excellent agreements between gas chemistry measured by QMS (quadrupole mass spectrometer) during stepwise crushing and the expected characteristics of SFIs and PFIs in the same samples acquired using Raman spectroscopy. In this study, we applied this QMS-based gentle stepwise crushing technique on ore and gangue minerals from the world-class Yaogangxian tungsten deposit in South China. Gases released from PFIs in cassiterite, wolframite, and quartz from ore-bearing veins show high CH4, N2, C3H8, and low CO2, C4H10 contents, low CO2/CH4 (≪1) and high N2/Ar (327–861 for ore minerals and 60.7–943 for quartzs from ore veins) ratios, along with multiple organic gaseous species. Their compositions resemble those of gases released from PFIs in quartzs from the Yaogangxian granites which represent magmatic-hydrothermal fluids that exsolved from the granitic magma. However, compared with these exsolved magmatic-hydrothermal fluids, ore mineral PFIs have relatively high He contents which indicate contributions from non-magmatic crustal fluids. This is consistent with high Ca2+, low F− concentrations, and low K+/Na+ (0.21–0.32) ratios observed in fluids in the quartz samples, as well as their relatively low water hydrogen isotopes (δD-H2O = −102 to −59‰). These chemical characteristics, coupled with their magmatic sulfur (δ34S-molybdenite and arsenopyrite = −0.2–1.4‰), methane hydrogen (δD-CH4 = −58 to −42‰), and fluid oxygen (δ18O-H2O = 3.9–5.1‰) isotopic compositions, indicate both magmatic and non-magmatic crustal components in the mineralizing fluids. Based on these observations and the low methane carbon isotope values (δ13C-CH4) in the studied quartz samples, we propose that fluid-rock interactions between the exsolved magmatic-hydrothermal fluids and the metasedimentary wall rocks played an important role in promoting W-Sn precipitation in this ore deposit. This study demonstrates the power of combining QMS-based stepwise crushing technique with traditional geochemical techniques in investigating ore-forming processes.

Abstract 2827: Inactivating calcium-sensing receptor polymorphisms at rs1801725 are associated with increased risk of secondary malignancies

Abstract The dysregulation of systemic calcium homeostasis during malignancy is common in most patients with high-grade tumors. The associated comorbidity is known as cancer-induced hypercalcemia (CIH) which affects up to 30% of cases, in the absence of metastasis. In the course of breast cancer progression, the secretion of parathyroid hormone-related protein (PTHrP) by tumor cells and the associated destruction of bone tissues, leads to a progressive increase in systemic calcium or CIH. The increase in circulating Ca2+ is sensed by the calcium-sensing receptor (CaSR), which plays a significant role in maintaining Ca2+ homeostasis. More than 200 mutations and single nucleotide polymorphisms (SNPs) in the CaSR gene have been described, including the A986S CaSR at rs1801725 and Q1011E CaSR at rs1801726 SNPs with reduced sensitivity to Ca2+. Interestingly, high circulating Ca2+ is associated with aggressive breast tumors in premenopausal women and larger tumors in postmenopausal women; however, the contribution of the CaSR in breast cancer progression remains poorly understood. Unlike SNPs at rs1801726, up to 20% of breast cancer patients with SNPs at rs1801725 may be predisposed to higher circulating Ca2+ in the course of their disease. Since breast cancer frequently metastasizes to Ca2+ rich skeletal tissues, we hypothesize that the development of CIH and subsequent desensitization of the CaSR by sustained high Ca2+ is critical for both the adaptation of TNBC cells to CIH in Ca2+ rich microenvironments and TNBC progression. Our preliminary data reveal that the expression level and mutational status of the CaSR is cell type-specific, and that sustained high Ca2+ desensitizes the receptor, but promotes tumor cell growth and motility. In addition, our preliminary data show that the A986S SNP is associated with hypercalcemia, secondary malignancy of bone and respiratory organs, and deficiency of humoral immunity. This study provides novel insights into not only the adaptation of TNBC cells to high circulating Ca2+, but also suggests that mutations of the CaSR at rs1801725 are predictive of the likelihood for metastasis to lungs and bone. Citation Format: Heather K. Beasley, Ky'Era V. Actkins, Annika B. Faucon, Lea K. Davis, Amos M. Sakwe. Inactivating calcium-sensing receptor polymorphisms at rs1801725 are associated with increased risk of secondary malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2827.

A combined modelling and experimental study of the removal of 133Ba from geothermal basin water using the MnO2-PAN and TK101 resins

The presence of Naturally Occurring Radionuclides (NORs) in geothermal fluids is a recurring issue in geothermal projects all over the world. During the first pumping tests of the production well MOL-GT-S1-01 at the Balmatt geothermal plant (Mol, Belgium) in 2015, the geothermal water was transferred towards a nearby basin. The original geothermal fluid was characterized by a226Ra concentration of ~170 Bq L−1 (February 2019). In the meantime, the water in the basin was exposed to multiple cycles of rainfall and evaporation. In June 2019, the concentration of 226Ra in the basin water was ~24 Bq L−1. As the concentration of the water is still too high to be discarded as non-radioactive waste water, finding a solution to remove the radium from the basin water is required. In order to achieve this objective, two resins, namely the MnO2-PAN resin and the TK101 resin, were tested for their sorption capacity to remove the 226Ra by using 133Ba as proxy in batch-type experiments performed in the laboratory. The TK101 resin did not show a sufficient sorption capacity for 133Ba and is therefore not considered to be useful to remove 226Ra from the basin water. The MnO2-PAN resin however, showed promising results. A sorption yield of 86% was reached at pH 9.2 after a contact time of one week. At high pH, some co-precipitation of 133Ba with carbonate minerals comprising significant amounts of Ca2+ and Mg2+ was observed. Total sorption was higher at pH = 9.2 (maximum sorption) than at the pH of the basin water (pH = 7.5). Even at high Ca2+ concentrations in the solution (i.e. 5 g L−1), there was almost no competition of Ca2+ for Ba2+ sorption sites on the resin. The modelling of the sorption edge experiments with the MnO2-PAN resin showed that mainly Cu and Mn were competitive for the sorption sites at low pH values (2.0 ≤ pH ≤ 4.5), while at acid to neutral pH values (4.5 ≤ pH ≤ 7), Zn and Ni became more competitive. At high pH values (pH ≥ 7.0), Cd started to compete with Ba for the sorption sites of the resin. The modelling of the kinetic experiments showed that these results could best be described by a pseudo second-order kinetic model of the form dqdt=k2(qe−qt)2.

The effect of construction dust and agricultural fertilization on the precipitation chemical composition during summer in the Yangtze River Delta area, China

To study the effect of construction dust and agricultural fertilization on the chemical composition characteristics of precipitation during the summer in the Yangtze River Delta region (China), the chemical composition of 144 precipitation samples collected at Wuxi from June 6th to July 15th in 2016 was analyzed. The results demonstrated that the pH values varied from 4.72 to 7.08 for all the precipitation events sampled, with the average pH value as high as 5.88. More than 68% of precipitation events showed pH values higher than 5.6, indicating lower acidic characteristics. The concentrations of anionic ions followed the order of SO42− > Cl− > NO3− > F− > NO2−, indicating SO42−, Cl− and NO3− were the main anions. The concentration of cationic ions followed the order of Ca2+ > NH4+ > Na+ > Mg2+ > K+, indicating Ca2+ and NH4+ were the main cations. The construction dust and agricultural fertilization were responsible for the increase of Ca2+and NH4+ concentration. Significant correlations between NH4+ and SO42− were found, indicating the neutralization ions and combination of all acidic had a great influence on acidity. The higher pH value could be attributed to the neutralization by the high concentration Ca2+, which is proven by the neutralization potential and acidic potential. The average value of fractional acidity is 0.28, indicating approximately 72% acidity is neutralized by alkaline composition. The influence of anthropogenic sources was dominant in chemical composition, higher than the marine and crustal source.

The ATF6\u03b2-calreticulin axis promotes neuronal survival under endoplasmic reticulum stress and excitotoxicity

While ATF6α plays a central role in the endoplasmic reticulum (ER) stress response, the function of its paralogue ATF6β remains elusive, especially in the central nervous system (CNS). Here, we demonstrate that ATF6β is highly expressed in the hippocampus of the brain, and specifically regulates the expression of calreticulin (CRT), a molecular chaperone in the ER with a high Ca2+-binding capacity. CRT expression was reduced to ~ 50% in the CNS of Atf6b−/− mice under both normal and ER stress conditions. Analysis using cultured hippocampal neurons revealed that ATF6β deficiency reduced Ca2+ stores in the ER and enhanced ER stress-induced death. The higher levels of death in Atf6b−/− neurons were recovered by ATF6β and CRT overexpressions, or by treatment with Ca2+-modulating reagents such as BAPTA-AM and 2-APB, and with an ER stress inhibitor salubrinal. In vivo, kainate-induced neuronal death was enhanced in the hippocampi of Atf6b−/− and Calr+/− mice, and restored by administration of 2-APB and salubrinal. These results suggest that the ATF6β-CRT axis promotes neuronal survival under ER stress and excitotoxity by improving intracellular Ca2+ homeostasis.

Preparation and Properties of Calcium Doped Carbon Nanofibers Photothermal Reagent

Recently, carbon nanomaterials illustrated great application prospect in tumor photothermal therapy (PTT). Meanwhile, numerous studies have shown that destruction of calcium homeostasis in cells can also be used as an effective strategy to inhibit tumor. Therefore, dual effect Ca2+ doped carbon nanofibers (PCNFs-Ca) photothermal reagents were prepared by electrospinning technique in this study. The spinnability, morphology and photothermal effect of different content of calcium doped carbon nanofibers were analyzed by field emission scanning electron microscopy (SEM), X-ray diffraction (XRD) and infrared thermometer. The results suggested that a dual effect photothermal reagent with high Ca2+ content was prepared to achieve significant effect in tumor inhibition on the premise of less influence on the photothermal properties of carbon nanofibers.

Investigating Day and Nighttime Variability of Major Water-Soluble Inorganic Species and Role of Reactive Nitrogen Species in PM2.5 and PM10 - A Two Year Study

The study reports day and nighttime temporal variation of prominent water-soluble inorganic species (WSIS) of fine and coarse mode particulate matter at a site in central Delhi for 2012 and 2013. The two years’ concentrations of major ionic species (NH4+, K+, Ca2+ and Mg2+ and NO3-, SO42-) showed that mean levels of both ∑cations and ∑anions were higher in nighttime than daytime in both PM2.5 and PM10. Moreover, the difference of mean levels in daytime and nighttime was noticed higher in PM2.5 compared to PM10. Among anions, more variation was observed for NO3-, i.e., ~49% higher level in nighttime compared to daytime, while~9% higher values in the nighttime for SO42-. Higher variation of NO3- level might be due to active participation of NOx in daytime photo-oxidation process. Among cations,Ca2+ and Mg2+ showed higher concentration in daytime compared to nighttime. Higher day and nighttime variation of Ca2+ and Mg2+ in coarse particulate matter suggested their dominance in PM10 compared to PM2.5. In PM10, the highest Ca2+ concentration was observed in daytime summer and least in nighttime monsoon, indicating the role of loose soil and meteorological conditions. The higher daytime SO42- concentration in monsoon compared to summer show edits significant formation as secondary aerosols in fine mode. The reactive nitrogen species NO3- and NH4+ were correlated during the day and nighttime in PM2.5 and PM10.Moreover, NH4+ was highly correlated to SO42- and NO3-, mainly in the form of (NH4)2SO4 and NH4NO3.

Relationships among ß-hydroxybutyrate, calcium and non-esterified fatty acids in blood with milk yield losses at early lactation

The objectives were to study the associations of concentrations of β-hydroxybutyrate acid (BHBA), calcium (Ca2+), and non-esterified fatty acids (NEFA) in blood serum 7 d prepartum with losses in milk yield (MY) and metabolic dysfunctions at seven and 14 d of lactation. Three hundred and thirty-six (336) Holstein-Friesian (780 ± 36 kg BW; which had lactated more than twice) were sampled by coccygeal venipuncture, 7 d before, and 7 and 14 d after parturition. For each sample and metabolite serum concentrations were stratified in thresholds and related to MY. When BHBA levels were high 7 d before parturition and were related to MY at d-7 postpartum, it was observed that 11.00 % of the cows lost 0.370 kg d-1 of milk. In contrast, no relationship was observed between BHBA prepartum and MY on d-14 of lactation. It was not observed any association between high NEFA and low Ca2+ levels prepartum and MY. NEFA concentrations ≥ 0.5 mmol L-1 on d-7 before calving were 7.6 more susceptible for lameness incidence (P≤ 0.01), and when BHBA ≥ 0.8 mmol L-1 cows were 2.4 times more likely to develop ketosis (P≤0.05) in the first 60 d in milk. In brief, data indicate that a high proportion of cows are above the thresholds of β-hydroxybutyrate and non-esterified fatty acids, and are also deficient in calcium, when determined one week before parturition. The risk thresholds for each metabolite were not associated with the amount of milk lost at d-14 after calving.

Molecular Mechanisms of the Deregulation of Muscle Contraction Induced by the R90P Mutation in Tpm3.12 and the Weakening of This Effect by BDM and W7.

Point mutations in the genes encoding the skeletal muscle isoforms of tropomyosin can cause a range of muscle diseases. The amino acid substitution of Arg for Pro residue in the 90th position (R90P) in γ-tropomyosin (Tpm3.12) is associated with congenital fiber type disproportion and muscle weakness. The molecular mechanisms underlying muscle dysfunction in this disease remain unclear. Here, we observed that this mutation causes an abnormally high Ca2+-sensitivity of myofilaments in vitro and in muscle fibers. To determine the critical conformational changes that myosin, actin, and tropomyosin undergo during the ATPase cycle and the alterations in these changes caused by R90P replacement in Tpm3.12, we used polarized fluorimetry. It was shown that the R90P mutation inhibits the ability of tropomyosin to shift towards the outer domains of actin, which is accompanied by the almost complete depression of troponin’s ability to switch actin monomers off and to reduce the amount of the myosin heads weakly bound to F-actin at a low Ca2+. These changes in the behavior of tropomyosin and the troponin–tropomyosin complex, as well as in the balance of strongly and weakly bound myosin heads in the ATPase cycle may underlie the occurrence of both abnormally high Ca2+-sensitivity and muscle weakness. BDM, an inhibitor of myosin ATPase activity, and W7, a troponin C antagonist, restore the ability of tropomyosin for Ca2+-dependent movement and the ability of the troponin–tropomyosin complex to switch actin monomers off, demonstrating a weakening of the damaging effect of the R90P mutation on muscle contractility.

Calcium-Sensing Receptors Control CYP27B1-Luciferase Expression: Transcriptional and Posttranscriptional Mechanisms.

25-hydroxyvitamin D 1α-hydroxylase (encoded by CYP27B1), which catalyzes the synthesis of 1,25-dihydroxyvitamin D3, is subject to negative or positive modulation by extracellular Ca2+ (Ca2+o) depending on the tissue. However, the Ca2+ sensors and underlying mechanisms are unidentified. We tested whether calcium-sensing receptors (CaSRs) mediate Ca2+o-dependent control of 1α-hydroxylase using HEK-293 cells stably expressing the CaSR (HEK-CaSR cells). In HEK-CaSR cells, but not control HEK-293 cells, cotransfected with reporter genes for CYP27B1-Photinus pyralis (firefly) luciferase and control Renilla luciferase, an increase in Ca2+o from 0.5mM to 3.0mM induced a 2- to 3-fold increase in firefly luciferase activity as well as mRNA and protein levels. Surprisingly, firefly luciferase was specifically suppressed at Ca2+o ≥ 5.0mM, demonstrating biphasic Ca2+o control. Both phases were mediated by CaSRs as revealed by positive and negative modulators. However, Ca2+o induced simple monotonic increases in firefly luciferase and endogenous CYP27B1 mRNA levels, indicating that the inhibitory effect of high Ca2+o was posttranscriptional. Studies with inhibitors and the CaSR C-terminal mutant T888A identified roles for protein kinase C (PKC), phosphorylation of T888, and extracellular regulated protein kinase (ERK)1/2 in high Ca2+o-dependent suppression of firefly luciferase. Blockade of both PKC and ERK1/2 abolished Ca2+o-stimulated firefly luciferase, demonstrating that either PKC or ERK1/2 is sufficient to stimulate the CYP27B1 promoter. A key CCAAT box (−74 bp to −68 bp), which is regulated downstream of PKC and ERK1/2, was required for both basal transcription and Ca2+o-mediated transcriptional upregulation. The CaSR mediates Ca2+o-dependent transcriptional upregulation of 1α-hydroxylase and an additional CaSR-mediated mechanism is identified by which Ca2+o can promote luciferase and possibly 1α-hydroxylase breakdown.

124-OR: Repetitive Ca2+ Waves Emanate from a Stable Leader Cell in Mouse Islets

Pancreatic beta cells form a highly connected network within the islet, with transcriptomic and functional heterogeneity existing between individual cells. A sub-population of leader cells has been proposed to act as functional hubs, controlling islet responses to glucose and other secretagogues. Using high speed confocal Ca2+ imaging, we aimed here to examine (a) the role of these cells in wave propagation and (b) their stability over time. Methods: Islets were isolated from C57BL6 male mice expressing the recombinant Ca2+ probe GCaMP6f selectively in the beta cell (Ins1Cre:GCaMP6f/f). Islets were then infected with an adenovirus expressing photo-activatable- (PA) mCherry. Ca2+ imaging was performed across a single islet plane in modified KREBS-Ringer medium at 11mM glucose using a Zeiss LSM 810 laser-scanning microscope and data acquisition at 5 Hz. Cells were photopainted by excitation of PA-mCherry at 405nm. Results: Leader cells were identified as those exhibiting the first detectable increase in Ca2+ signal during subsequent Ca2+ waves. The great majority of islets (85%, n=26, three independent experiments) displayed repetitive Ca2+ waves (1.10±0.26 min-1), and 82.9±5.0% of waves propagated directly from an identifiable leader cell. There was an average of 2.5±0.4 leader cells per islet with 62.9±0.70% of waves emanating from a “principal” leader cell. Ca2+ imaging experiments performed 16 h after the original session revealed that 37±0.08% (n=4) of waves emanated from the same, now photopainted, leader cell. Conclusions: These data suggest that (a) a complex, non-binary, heterogeneity exists between leader and follower beta cells, (b) leader behaviour is an intrinsic phenotype of a sub-population of cells with a half-life in this role of ∼12 h. Disclosure P. L. Chabosseau: None. A. Martinez-sanchez: None. I. Leclerc: Consultant; Spouse/Partner; Sun Pharmaceutical Industries Ltd. V. Salem: None. G. A. Rutter: Advisory Panel; Self; Sun Pharmaceutical Industries Ltd.

Softening Hard Water using Cocoa Shell Activated Charcoal

Cocoa pod shells contain 23-54 % cellulose, 1.14 % hemicellulose, and 20-27.95 % lignin. The high cellulose content in the cocoa pod shell has the potential to be further processed into adsorbents. Before being used as an adsorbent, activation using HCl solution was carried out to increase the adsorption power of the cocoa shell. This research was conducted to analyze the influence of adsorbent dose, pH solution, the efficiency of hard water reduction, and adsorption capacity on Ca2+ and Mg2+ ions. Adsorption of hard water ions was conducted by varying adsorbent doses of 1, 3, 5, 7, and 9 g and varying at the pH of 5, 6, 7, 8, and 9. Optimum condition achieved at the mass of 5 g with Ca2+ and Mg2+ ions adsorption efficiency of 85.4 and 18.31%, respectively. Optimum condition achieved at the pH of 9 with Ca2+ and Mg2+ ions adsorption efficiency of 61.54 and 49.11%, respectively. The highest Ca2+ and Mg2+ ions adsorption capacity was obtained at the adsorbent mass of 1 g with adsorption capacity respectively 4.05 and 0.54 mg/g. The highest Ca2+ and Mg2+ ions adsorption capacity was obtained at a pH of 9 with an adsorption capacity of 4.05 and 0.54 mg/g, respectively.

Effect of Active Coatings Containing Lippa citriodora Kunth. Essential Oil on Bacterial Diversity and Myofibrillar Proteins Degradation in Refrigerated Large Yellow Croaker.

The research evaluated the effects of locust bean gum (LBG) and sodium alginate (SA) active coatings containing 0.15, 0.30 or 0.60% lemon verbena (Lippa citriodora Kunth.) essential oil (LVEO) on the bacterial diversity and myofibrillar proteins (MPs) of large yellow croaker during refrigerated storage at 4 °C for 18 days. Variability in the dominant bacterial community in different samples on the 0, 9th and 18th day was observed. Pseudomonas and Shewanella were the two major genera identified during refrigerated storage. At the beginning, the richness of Pseudomonas was about 37.31% and increased for control (CK) samples during refrigerated storage, however, the LVEO-treated samples increased sharply from day 0 to the 9th day and then decreased. LBG-SA coatings containing LVEO treatments significantly delayed MPs oxidation by retarding the formation of free carbonyl compounds and maintaining higher sulfhydryl content, higher Ca2+-ATPase activity, better organized secondary (higher contents of α-helix and β-sheet) and tertiary structures during refrigerated storage. The transmission electron microscope (TEM) images showed that the integrity of the sarcomere was damaged; the boundaries of the H-, A-, and I-bands, Z-disk, and M-line were fuzzy in the CK samples at the end of storage. However, the LVEO-treated samples were still regular in appearance with distinct dark A-bands, light I-bands, and Z-disk. In brief, LBG-SA active coatings containing LVEO treatments suggested a feasible method for protecting the MPs of large yellow croaker during refrigerated storage.

Ouabain worsens diastolic sarcomere length in myocytes from a cardiomyopathy mouse model

Diastolic dysfunction is a major feature of hypertrophic cardiomyopathy (HCM). Data from patient tissue and animal models associate increased Ca2+ sensitivity of myofilaments with altered Na+ and Ca2+ ion homeostasis in cardiomyocytes with diastolic dysfunction. In this study, we tested the acute effects of ouabain on ventricular myocytes of an HCM mouse model. The effects of ouabain on contractility and Ca2+ transients were tested in intact adult mouse ventricular myocytes (AMVMs) of Mybpc3-targeted knock-in (KI) and wild-type (WT) mice. Concentration-response assessment of contractile function revealed low sensitivity of AMVMs to ouabain (10 μM) compared to literature data on human cardiomyocytes (100 nM). Three hundred μM ouabain increased contraction amplitude (WT ~1.8-fold; KI ~1.5-fold) and diastolic intracellular Ca2+ in both WT and KI (+12–18%), but further decreased diastolic sarcomere length in KI cardiomyocytes (−5%). Western Blot analysis of whole heart protein extracts revealed 50% lower amounts of Na+/K+ ATPase (NKA) in KI than in WT. Ouabain worsened the diastolic phenotype of KI cardiomyocytes at concentrations which did not impair WT diastolic function. Ouabain led to an elevation of intracellular Ca2+, which was poorly tolerated in KI showing already high cytosolic Ca2+ at baseline due to increased myofilament Ca2+ sensitivity. Lower amounts of NKA in KI could amplify the need to exchange excessive intracellular Na+ for Ca2+ and thereby explain the general tendency to higher diastolic Ca2+ in KI.

The Calcium-Sensing Receptor (CaSR) Variants at rs1801725 Increase the Risk of Developing Secondary Malignant Cancers

The dysregulation of systemic calcium homeostasis during malignancy is common in most patients with high-grade tumors. The associated comorbidity is known as cancer-induced hypercalcemia (CIH) which affects up to 30% of cases, in the absence of metastasis. In the course of breast cancer progression, the secretion of parathyroid hormone-related protein (PTHrP) by tumor cells and the associated destruction of bone tissues, leads to a progressive increase in systemic calcium or CIH. The increase in circulating Ca2+ is sensed by the calcium-sensing receptor (CaSR), which plays a significant role in maintaining Ca2+ homeostasis. More than 200 mutations and single nucleotide polymorphisms (SNPs) in the CaSR gene have been described, including the A986S CaSR at rs1801725 and Q1011E CaSR at rs1801726 SNPs with reduced sensitivity to Ca2+. Interestingly, high circulating Ca2+ is associated with aggressive breast tumors in premenopausal women and larger tumors in postmenopausal women; however, the contribution of the CaSR in breast cancer progression remains poorly understood. Unlike SNPs at rs1801726, up to 20% of breast cancer patients with SNPs at rs1801725 may be predisposed to higher circulating Ca2+ in the course of their disease. Since breast cancer frequently metastasizes to Ca2+ rich skeletal tissues, we hypothesize that the development of CIH and subsequent desensitization of the CaSR by sustained high Ca2+ is critical for both the adaptation of TNBC cells to CIH in Ca2+ rich microenvironments and TNBC progression. Our preliminary data reveal that the expression level and mutational status of the CaSR is cell type-specific, and that sustained high Ca2+ desensitizes the receptor, but promotes tumor cell growth and motility. Sustained high Ca2+ also triggers the expression of metastasis promoting genes, including the cancer/testis antigen, MAGEC2, and Plasminogen Activator Inhibitor, PAI-2, potentially via the early response genes FOS/FOSB. In addition, our preliminary data show that the A986S SNP is associated with hypercalcemia, secondary malignancy of bone and respiratory organs, and deficiency of humoral immunity. This study provides novel insights into not only the adaptation of TNBC cells to high circulating Ca2+, but also suggests that mutations of the CaSR at rs1801725 are predictive of the likelihood for metastasis to lungs and bone.

Polyunsaturated Fatty Acids (PUFA) Increases the Sensitivity of Saccharomyces cerevisiae to Ethanol by Impairing the Function of the Mitochondrial Unselective Channel (MUC)

Yeast cells uncouple its respiration by opening a mitochondrial unselective channel (MUC) that dissipates the membrane potential and accelerates oxygen consumption in order to avoid a deleterious buildup of ROS. Yeast incorporates polyunsaturated fatty acids (PUFA) into membranes when available in its environment, increasing the sensitivity of membranes to oxidative damage. One factor causing oxidative stress in yeast is ethanol accumulation during fermentation. The MUC is constituted by the voltage-dependent anionic channel (VDAC), the adenine nucleotide translocator and the cyclophilin D, being the VDAC a sensor for Ca2+ levels that promotes MUC closing under high Ca2+ concentrations. Moreover, MUC function is dependent on the phospholipid cardiolipin. In this work, we propose that yeast become more susceptible to ethanol stress when grow in the presence of PUFA by the impairment of MUC function due to enhanced lipid peroxidation. Yeast cells were grown in liquid YPD medium with (+C18:3) or without (-C18:3) 1mM linolenic acid and 10% ethanol. Ethanol decreased yeast growth by 20% and 90% in –C18:3 and +C18:3 cells, respectively. Ethanol also promoted lipid peroxidation only in +C18:3 cells. The addition of amiodarone, which increases cytosolic Ca2+ levels and promotes the closure of MUC, decreased 80% the growth in –C18:3 cells, while the +C18:3 cells showed the same levels of growth inhibition than without amiodarone. In – C18:3 cells respiring in uncoupled state (U), amiodarone decreased respiration by promoting MUC closing and coupling. Conversely, respiration was slightly inhibited by amiodarone in the +C18:3 cells. The role of MUC in the deleterious effects of ethanol in +C18:3 cells was confirmed in yeast mutants depleted in cardiolipin and VDAC, as these cells became insensitive to the effects of amiodarone. These results suggest that increased sensitivity to ethanol elicited by C18:3 may be due to impaired MUC function due to enhanced lipid peroxidation.

Ellagic Acid Prevents Ca2+ Dysregulation and Improves Functional Abnormalities of Ventricular Myocytes via Attenuation of Oxidative Stress in Pathological Cardiac Hypertrophy.

The aim of this study was to investigate whether ellagic acid (EA) treatment can prevent changes in contractile function and Ca2+ regulation of cardiomyocytes in pathologic cardiac hypertrophy. Groups were assigned as Con group; an ISO group in which the rats received isoproterenol alone (5mg/kg/day); and an ISO + EA group in which the rats received isoproterenol and EA (20mg/kg/day) for 4weeks. Subsequently, fractional shortening, intracellular Ca2+ signals, and L-type Ca2+ currents of isolated ventricular myocytes were recorded. Protein expression levels were also determined by the Western blotting method. The survival rate was increased, and the upregulated cardiac hypertrophy markers were significantly attenuated with the EA treatment. The fractional shortening and relaxation rate of myocytes was decreased in the ISO group, whereas EA significantly improved these changes. Ventricular myocytes of the ISO + EA rats displayed lower diastolic Ca2+ levels, higher Ca2+ transients, shorter Ca2+ decay, and higher L-type Ca2+ currents than those of ISO rats. Protein expression analyses indicated that the upregulated p-PLB and p-CaMKII expressions were restored by EA treatment, suggesting improved calcium handling in the ISO + EA rat heart. Moreover, ISO rats displayed significantly increased expression of p-22phox and p47phox subunits of NOX2 protein. Expression of the p22phox subunit was reduced with EA administration, while the decrease in p47phox did not reach a significant level. The increased ROS impairs Ca2+ homeostasis and contractile activity of cardiac myocytes, whereas chronic EA administration prevents Ca2+ dysregulation and functional abnormalities associated with pathological cardiac hypertrophy via the diminution of oxidative stress.