Ca Uptake Research Articles

Bioactive glass doped with noble metal nanoparticles for bone regeneration: in vitro kinetics and proliferative impact on human bone cell line.

This work investigates the bioactivity of novel silver-doped (BG-Ag) and gold-doped (BG-Au) quaternary 46S6 bioactive glasses synthesized via a semi-solid-state technique. A pseudo-second-order kinetic model successfully predicted the in vitro uptake kinetic profiles of the initial ion-exchange release of Ca in simulated body fluid, the subsequent Si release, and finally, the adsorption of Ca and P onto the bioactive glasses. Doping with silver nanoparticles enhanced the rate of P uptake by up to approximately 90%; whereas doping with gold nanoparticles improved Ca and P uptake rates by up to about 7 and 2 times, respectively; as well as Ca uptake capacity by up to about 19%. The results revealed that the combined effect of Ca and Si release, and possibly the release of silver and gold ions into solution, influenced apatite formation due to their effect on Ca and P uptake rate and capacity. In general, gold-doped bioactive glasses are favoured for enhancing Ca and P uptake rates in addition to Ca uptake capacity. However, silver-doped bioactive glasses being less expensive can be utilized for applications targeting rapid healing. In vitro studies showed that BG, BG-Ag and BG-Au had no cytotoxic effects on osteosarcoma MG-63 cells, while they exhibited a remarkable cell proliferation even at low concentration. The prepared bioactive glass doped with noble metal nanoparticles could be potentially used in bone regeneration applications.

Critical Leaf Magnesium Concentrations for Adequate Photosynthate Production of Soilless Cultured Cherry Tomato—Interaction with Potassium

Magnesium (Mg) is essential to many plant physiological and biochemical processes; however, understanding how Mg nutrition quantitatively affects the production, partitioning, and utilization of photoassimilates is still lacking, especially in soilless culture systems. We focused on the roles of Mg in yield formation and interactions with potassium (K) nutrition of cherry tomato. Cherry tomato yield, photosynthetic parameters, dry matter weight, and K, Mg, and calcium (Ca) uptake were investigated in two soilless experiments with seven Mg levels and five K levels. The results showed that low (<1 mM) and high (>4 mM) Mg supply limited cherry tomato yield by decreasing dry matter accumulation by 22.6–78.1% and harvest index by 13.9–40.7%. The critical leaf Mg concentrations required for adequate photosynthate production in the first and second harvest periods were 4.67 and 5.52 g·kg−1, respectively. However, over-supply of Mg reduced leaf K and Ca concentrations and limited plant uptake of K and Ca. Moreover, adjusting K concentrations in solution could influence plant Mg functions in photosynthesis and, therefore, cherry tomato growth. Overall, balanced Mg and K application increased Mg, K, and Ca uptake, as well as Mg concentrations in leaves, which could maintain a sustainable photosynthetic rate and plant dry matter formation.

European beech leads to more bioactive humus forms but stronger mineral soil acidification as Norway spruce and Scots pine – Results of a repeated site assessment after 63 and 82 years of forest conversion in Central Germany

To reduce the effects of extended coniferous monoculture plantations on forest floor and topsoil processes, like amplified acidification or nutrient immobilization in organic layers, small interspersed groups of European beech were planted at the beginning of the 20th century amid large coniferous stands (CS) in Central Germany. Today, these so-called “Green Eyes” (GE) are 82-year old. In our study we focused on two different timelines to investigate the effects of forest conversion on vegetation composition, forest floor and mineral soil properties, encompassing a long-term (>80 year) comparison from tree planting in the 1930s to 2018 and a shorter timeframe nearly spanning 20 years (1999–2018). Since long-term forest conversion experiments (>60 years) across sites sharing a common forest land-use history are scarce, our study allows to contribute to a better evaluation of the long-term effects on changes in soil properties. We linked standard methods assessing soil pH, organic C and total N concentrations as well as stocks as indicators of soil quality changes in forest floor and mineral soil (down to 40 cm depth) to patterns in ground vegetation dynamics (most GE were characterized only by a few herbaceous species). Our results exhibited an effect of forest conversion on the activation in forest floor turnover resulting in increased turnover rates in the GE (GE contain only half of the forest floor OM of CS), hence forming more bioactive humus forms (mull, moder) and a noticeable higher forest floor pH (+0.6 units) compared to CS. The OC translocation from the forest floor into the topsoil is higher under GE (+0.7% OC content), probably building up a stable SOC pool hence contributing to C sequestration. The positive effects of European beech on forest floor quality are related to a stronger acidification of the subsoil during the past 20 years (-0.5 pH units). The base pump effect (uptake of Ca2+, Mg2+, K+ and assimilation into tree biomass in exchange release of H+) in GE led to more acidic conditions (-0.2 pH units) in the deeper mineral soil compared to CS. This bio-acidification may serve as one reason for subsoil acidification, as observed in our study, pointing out that mineral soil acidification is still an important issue in central European forests. Future restoration of soil base cation pools will still depend on the rate of bio-acidification, on the amount of acidifying air pollutant (and base cation) depositions and on forest management practices (e.g. intensity of biomass removal, soil regeneration-oriented liming).

Effects of potassium, calcium and magnesium ratios in soil on nutrient uptake by pummelo (Citrus maxima Merr.)

Potassium (K), calcium (Ca), and magnesium (Mg) are important nutrients for the pummelo’s growth and productivity. However, these nutrients are strongly antagonistic to each other. This study aims to examine the effects of different K, Ca, and Mg ratios in soil on nutrient uptake of pummelo plant. Soil samples were collected under pummelo canopies at a depth of 0 cm to 20 cm. Leaf samples of 3 to 5 month old were obtained from the same trees. The soil’s chemical properties and nutrient concentrations in the leaves were determined. The results showed that the P uptake was inhibited by a high Ca concentration in soil. High K/Mg ratio in soil (0.52 ± 0.27) positively affected on K uptake. Low K/Mg ratios in soil (0.42 ± 0.20) negatively affected on K uptake, although exchangeable K in soil was much higher than optimum ranges. The K/Ca mole ratio in the leaves was higher than that in the soil; therefore, the uptake of K was better than that of Ca, despite the lower concentration of K in the soil. Moreover, the uptake of K was better than that of Mg, because the K/Mg ratio in the leaves higher than that in the soil. Low exchangeable Ca negatively affected on Ca uptake, although Ca/Mg mole ratio in soil was high (2.77 ± 1.18).

Suppression of ventricular arrhythmia by mitochondrial calcium uptake via mitochondrial calcium uniporter in the ischemic heart failure mice

Abstract Background In heart failure (HF), diastolic calcium (Ca) leak from sarcoplasmic reticulum (SR) via ryanodine receptor (RyR) causes delayed after depolarization (DAD), leading ventricular arrhythmias (VAs). Recent study reported that Ca uptake into mitochondria via mitochondrial calcium uniporter (MCU) suppress Ca waves (CaWs) and DAD in catecholaminergic polymorphic ventricular tachycardia, in which diastolic Ca leak is thought to be a major cause of VAs as in HF. However, such anti-arrhythmic effect of mitochondrial Ca uptake via MCU remains unclear in HF. Purpose We sought to investigate whether mitochondrial Ca uptake via MCU decreases CAWs and VAs incidence in ischemic HF mice. Methods Ten-week-old male C57BL/6J mice were divided into 2 groups; sham operation mice (Sham) or HF mice (HF) in which myocardial infarction was induced by left coronary artery ligation. After 4–6 weeks, cardiomyocyte or mitochondria was isolated respectively from the myocardium of Sham and the non-infarct myocardium of HF. Influence of MCU activation on Ca dynamics, VA inducibility and left ventricular hemodynamics were evaluated using Kaemenpferol, a MCU activator. Intracellular Ca dynamics and mitochondrial Ca uptake were measured in isolated cardiomyocytes loaded with Fluo-4 AM on an epifluorescence microscopy and by estimating the extra-mitochondrial Ca reduction with Fluo-5N on a spectrofluoro-photometer, respectively. VAs was induced by programmed stimulation in the Langendorff perfused hearts. Left ventricular (LV) pressure was measured using a microtip transducer catheter. Finally, the effect of intravenous administration of Kaempferol (5mg/kg) on hemodynamic parameters was examined 30 minutes after administration in Sham and HF. Results HF mice showed left ventricular dysfunction, as well as the increased heart and lung weights compared to Sham. MCU protein expression in cardiomyocytes did not differ between Sham and HF. Kaempferol increased mitochondrial Ca uptake in the isolated mitochondria both in Sham and HF. The number of the diastolic CaWs was higher in HF compared to Sham. Such increased number of CaWs in HF was attenuated by 10 μM Kaempferol, which was, however, abolished by a MCU blocker Ruthenium Red. The incidence of induced VA was significantly higher in HF than Sham, which was suppressed by Kaempferol. In vivo measurements, intravenous administration of Kaempferol did not show significant changes in hemodynamic parameters in Sham and HF mice. Conclusions Mitochondrial Ca uptake via MCU suppresses CaWs and VAs, but did not change LV hemodynamics in HF. Whereas traditional antiarrhythmic drugs have limited use in heart failure patients, a novel strategy that promotes Ca uptake into mitochondria might be a new and safer option for treating VAs in HF. Funding Acknowledgement Type of funding source: None

Genotypic variation among chickpea and wild Cicer spp. in nutrient uptake with increasing concentration of solution Al at low pH

In many acidic soils, high concentrations of toxic Al3+ hamper plant growth by restricting root growth which in turn restricts water and nutrient absorption. Previous research showed variation among chickpea (Cicer arietinum L.) and wild Cicer species in root elongation at 15 μM Al or more, but effects on nutrient absorption have not been examined. The variation in nutrient uptake of two chickpea varieties (PBA HatTrick and PBA Striker) and two wild Cicer species (C. echinospermum (C. echi) and C. reticulatum (C. reti)) was determined in low pH (4.2) nutrient solution with increasing Al concentrations (0, 7.5, 15, 30 μM Al). While C. echi, PBA HatTrick and PBA Striker had thicker roots and more lateral roots compared to C. reti, C. reti had greater aluminium tolerance index (AlTI) at 15 and 30 μM Al. The C. echi had higher uptake of root and shoot Al (7.5, 15 and 30 μM Al), P and S (15 and 30 μM Al) while its uptake was marginally lower for Mg, Ca (all Al treatments) and K (15 and 30 μM Al). By contrast, C. reti contained higher shoot Ca concentration at 15 and 30 μM Al and it had lower root Al uptake. Manganese uptake by C. reti roots and shoots were high enough to induce moderate Mn toxicity at 0 and 7.5 μM Al. Therefore, in response to Al toxicity, C. reti maintained greater AlTI and restricted Al uptake while increasing Ca uptake.

Effect of bacterial consortium on alfalfa (Medicago sativa L.) plant nutrient uptake and antioxidant enzymes at different levels of oily sludge

Under stress environment of oily sludge, plants develop oxidative stress which effect nutrients uptake, activity of oxidative defence enzymes, cause ion imbalance and toxicity in plants. The present study was designed to develop a combination of bacterial consortium alone and with fertilizers that can help to improve alfalfa growth and plant defence system under stress environment of oily sludge contamination soils. For this study consortium was prepared from Bacillus cereus (Acc KR232400), Bacillus altitudinis (Acc KF859970), Comamonas (Acc KF859971) and Stenotrophomonas maltophilia (Acc KF859973) and was inoculated with fertilizer to oily sludge contaminated soils. A pot experiment was conducted using complete randomized design with three replicates. The plants were harvested at 21 d for estimation of protein, proline and antioxidant enzymes superoxide dismutase (SOD) and peroxidase (POD). The protein, SOD and POD contents in alfalfa were higher in oily sludge than soil without consortium, ammonium nitrate and diamamoiun phosphate. Consortium suppressed the oxidative stress of sludge treated plants. The inoculation of bacterial consortium enhanced the uptake of Ca, Mg, K and Na. The uptake of Ca, Mg, K, Fe, Cu and Zn increased significantly with consortium+fertilizer the availability of nutrients in soil with 30% and 60% of oily. Cd content was greater in root than leaves of alfalfa. The bacterial consortium helped to enhance plant growth and plant anti-oxidant enzymes system. The consortium with fertilizer is the best suitable combination for alfalfa that can improve the oxidative enzyme system of alfalfa and increases its growth and development.

Influence of Species Differences, Relative Metals Concentrations and pH on Uptake of Metals in Water by Fish

This study was designed to assess the effect of relative metals concentrations, pH and species variations on the uptake of copper (Cu), iron (Fe), calcium (Ca) and magnesium (Mg) in water, fish and fish parts to monitor the toxicity potentials of consuming these fish. The water and fish samples were obtained from four locations (Farin gada stream, Lamingo Dam, Nasco pond and mining pond) in Jos Metropolis, Plateau State, Nigeria, Water and six fish species samples were collected from the four locations, digested and analysed using Buck Scientific Atomic Absorption Spectrophotometer, model 210VGP. Results show that pH of the water sources from Farin gada stream, Lamingo Dam, Nasco pond and mining pond were 7.1, 6.5, 7.0 and 7.2 respectively. The concentrations of Cu in the water sources were 0.030±0.001, 0.010±0.003, 0.020±0.000, 0.027±0.000 in Farin Gada stream, Nasco pond, Lamingo Dam and mining pond respectively; Fe were 2.2±0.1, 0.0±0,000, 0.2±0.003 and 0.3±0.001; Ca were 305±3.0, 37±1.5, 110±3.5 and 163±4.5; Mg were 160±3.6, 126±4.8, 79±1.9 and 95±2.8 in that order above. Different fish species from the same water source bioaccumulated Cu, Fe, Ca and Mg at varying concentrations depending on source, fish species or the physicochemical properties. Different fish species have different preferences as to which part (body, gills and head) of the fish these metals are concentrated more. Lamingo Dam had five fish species, mining pond had three, while Nasco pond and Farin Gada stream had one each. The results established that uptake and bioavailability of Cu, Fe, Ca and Mg by fish in water depend on species variation, relative concentration of the metals in the source of water and the pH of the water.

Bioavailability of macro‐ and micro‐nutrients chemically extracted in acidic soils for wheat

AbstractBackground: Chemical methods allowing a single soil extraction followed by multi‐elemental simultaneous measurement by ICP‐OES are increasingly used to predict plant uptake; however, calibration results against crop response are scarce and contradictory.Aims: Our aims were to evaluate the efficacy of five extractants to predict nutrient uptake by a greenhouse wheat crop, as well as the influence of soil properties on nutrient concentrations in soil extracts and wheat plants.Methods: Unlike other calibration studies, we monitored the pre‐seeding to post‐harvesting changes in soil available Ca, K, Mg, Cu, Fe, Mn, Zn, and Al. We extracted 14 acidic soils (C content: 47–114 g kg−1) with two traditional (AA: ammonium acetate; DTPA: diethylenetriamine‐pentaacetic acid) and three multi‐element extractants (AB‐DTPA: ammonium bicarbonate‐DTPA; Mehlich‐3; AA‐DTPA: ammonium acetate‐DTPA).Results: Relationships between bioavailable and chemically extractable elements were strong for K (R2 = 0.776 to R2 = 0.882; p < 0.001) and Zn (R2 = 0.663 to R2 = 0.721; p < 0.001), especially for AB‐DTPA and AA‐DTPA. Multiple regressions including also soil properties can predict wheat‐Ca (Feoxihydroxides, clay and CaAB‐DTPA; R2 = 0.656; p < 0.001) and wheat‐Cu [Aloxihydroxides and either CuAB‐DTPA (R2 = 0.515; p < 0.01) or CuAA‐DTPA (R2 = 0.472; p < 0.01)]. Pre‐seeding to post‐harvesting changes in KAA‐DTPA and KAB‐DTPA were strongly related with K uptake by wheat (R2 = 0.927 and R2 = 0.949, respectively; p < 0.001); similarly, for wheat‐Zn the best relationships were with ZnMehlich‐3 and ZnAA‐DTPA (R2 = 0.654 and R2 = 0.757, respectively; p < 0.001).Conclusion: Consequently, chemical extractants alone can adequately predict K and Zn bio‐availability, and combined with some soil properties can predict wheat uptake of Ca and Cu, but not that of other nutrients.

Calcium uptake through skins of sweet cherry fruit: Effects of different calcium salts and surfactants

Increasing fruit calcium (Ca) raises the quality of sweet cherry fruit. The objective was to quantify Ca mass per fruit following exposure of developing fruits to Ca salt solutions by submersion or by spraying. Mass of Ca per fruit was quantified by atomic absorption spectrometry.Time courses of Ca mass per fruit following treatment with Ca-chloride or Ca-formate revealed increasing Ca mass with time. Calcium uptake by late stage III fruit (harvest mature) generally exceeded that by stage II fruit (pit mature). Increasing Ca salt concentration increased Ca mass per fruit. The increase in Ca mass was reduced, if the pedicel cavity had previously been sealed with silicone rubber, but sealing the stylar scar had little effect. Submersion and spraying with a range of Ca salts increased Ca mass per fruit, but Ca uptake was greatest for Ca-nitrate and least for Ca-lactate or Ca-heptagluconate. There was little difference in uptake between Ca-acetate, Ca-chloride, Ca-formate or Ca-propionate. The effects on Ca uptake of additions of surfactants depended on the surfactant, the mode of application, the fruit cultivar and the developmental stage. Spraying with Ca salts in combination with Glucopon CSUP and Break-Thru S 240 showed no gain in Ca. Occasionally with ‘Hedelfinger’, Ca uptake was actually decreased by the addition of surfactant, compared with the no-surfactant controls. The latter likely resulted from a decrease in the volume of Ca solution retained on the sprayed fruit surface due to more complete surface drainage with Break-Thru S 240.The results show that spraying fruit with solutions of various Ca salts increases Ca mass per fruit. The increase is the result of penetration of Ca through the fruit skin and also through the pedicel:fruit junction. The various anion partners of the Ca salts examined made surprisingly little difference to the amount of Ca penetrating the fruit skin. Calcium uptake from those salts having lower points of deliquescence and higher water solubility was slightly greater.

Effect of Oxygen Free Radicals on Cardiac Contractile Activity and Sarcolemmal Na(+)-Ca(2+) Exchange.

BACKGROUND: Although oxygen free radicals have been shown to induce myocardial cell damage and cardiac dysfunction, the exact mechanism by which these radicals affect the heart function is not clear. Since the occurrence of intracellular Ca(2+) overload is critical in the genesis of cellular damage and cardiac dysfunction, and since the sarcolemmal Na(+)-Ca(2+) exchange is intimately involved in Ca(2+) movements in myocardium, this study was undertaken to examine the effects of oxygen free radicals on the relationship between changes in cardiac contractile force development and sarcolemmal Na(+)-Ca(2+) exchange activity. METHODS AND RESULTS: Isolated rat hearts were perfused with a medium containing xanthine plus xanthine oxidase for different times, and changes in contractile force as well as sarcolemmal Na(+)-(2+) exchange activity were monitored. Perfusion of the heart with xanthine plus xanthine oxidase resulted in a transient increase followed by a marked decrease in contractile activity; the resting tension was markedly increased. The xanthine plus xanthine oxidase-induced depression in developed tension, rate of contraction, and rate of relaxation, except the transient increase in contractile activity, was prevented by the addition of catalase, but not by superoxide dismutase, in the perfusion medium. A time-dependent depression in sarcolemmal Na(+)-Ca(2+) was also evident upon perfusing the heart with xanthine plus xanthine oxidase. This depression in Na(+)-dependent Ca(2+) uptake was associated with a decrease in the maximal velocity of reaction without any changes in the affinity of Na(+)-Ca(2+) exchanger for Ca(2+). The presence of catalase, unlike superoxide dismutase, prevented the decrease in sarcolemmal Na(+)-Ca(2+) exchange activity in hearts perfused with xanthine plus xanthine oxidase. CONCLUSIONS: The results support the view that a depression in the sarcolemmal Na(+)-Ca(2+) exchange activity may contribute to the occurrence of intracellular Ca(2+) overload and subsequent decrease in contractile activity. Furthermore, these actions of xanthine plus xanthine oxidase in the whole heart appear to be a consequence of H(2)O(2) production rather than the generation of superoxide radicals.

Mitochondrial calcium uniporter complex activation protects against calcium alternans in atrial myocytes.

Cardiac alternans, defined as beat-to-beat alternations in action potential duration, cytosolic Ca transient (CaT) amplitude, and cardiac contraction is associated with atrial fibrillation (AF) and sudden cardiac death. At the cellular level, cardiac alternans is linked to abnormal intracellular calcium handling during excitation-contraction coupling. We investigated how pharmacological activation or inhibition of cytosolic Ca sequestration via mitochondrial Ca uptake and mitochondrial Ca retention affects the occurrence of pacing-induced CaT alternans in isolated rabbit atrial myocytes. Cytosolic CaTs were recorded using Fluo-4 fluorescence microscopy. Alternans was quantified as the alternans ratio (AR = 1 - CaTsmall/CaTlarge, where CaTsmall and CaTlarge are the amplitudes of the small and large CaTs of a pair of alternating CaTs). Inhibition of mitochondrial Ca sequestration via mitochondrial Ca uniporter complex (MCUC) with Ru360 enhanced the severity of CaT alternans (AR increase) and lowered the pacing frequency threshold for alternans. In contrast, stimulation of MCUC mediated mitochondrial Ca uptake with spermine-rescued alternans (AR decrease) and increased the alternans pacing threshold. Direct measurement of mitochondrial [Ca] in membrane permeabilized myocytes with Fluo-4 loaded mitochondria revealed that spermine enhanced and accelerated mitochondrial Ca uptake. Stimulation of mitochondrial Ca retention by preventing mitochondrial Ca efflux through the mitochondrial permeability transition pore with cyclosporin A also protected from alternans and increased the alternans pacing threshold. Pharmacological manipulation of MCUC activity did not affect sarcoplasmic reticulum Ca load. Our results suggest that activation of Ca sequestration by mitochondria protects from CaT alternans and could be a potential therapeutic target for cardiac alternans and AF prevention.NEW & NOTEWORTHY This study provides conclusive evidence that mitochondrial Ca uptake and retention protects from Ca alternans, whereas uptake inhibition enhances Ca alternans. The data suggest pharmacological mitochondrial Ca cycling modulation as a potential therapeutic strategy for alternans-related cardiac arrhythmia prevention.

Ocean acidification effects on calcification and dissolution in tropical reef macroalgae

Net calcification rates for coral reef and other calcifiers have been shown to decline as ocean acidification (OA) occurs. However, the role of calcium carbonate dissolution in lowering net calcification rates is unclear. The objective of this study was to distinguish OA effects on calcification and dissolution rates in dominant calcifying macroalgae of the Florida Reef Tract, including two rhodophytes (Neogoniolithon strictum, Jania adhaerens) and two chlorophytes (Halimeda scabra, Udotea luna). Two experiments were conducted: (1) to assess the difference in gross (45Ca uptake) versus net (total alkalinity anomaly) calcification rates in the light/dark and (2) to determine dark dissolution (45CaCO3), using pH levels predicted for the year 2100 and ambient pH. At low pH in the light, all species maintained gross calcification rates and most sustained net calcification rates relative to controls. Net calcification rates in the dark were ~84% lower than in the light. In contrast to the light, all species had lower net calcification rates in the dark at low pH with chlorophytes exhibiting net dissolution. These data are supported by the relationship (R2 = 0.82) between increasing total alkalinity and loss of 45Ca from pre-labelled 45CaCO3 thalli at low pH in the dark. Dark dissolution of 45CaCO3-labelled thalli was ~18% higher in chlorophytes than rhodophytes at ambient pH, and ~ twofold higher at low pH. Only Udotea, which exhibited dissolution in the light, also had lower daily calcification rates integrated over 24 h. Thus, if tropical macroalgae can maintain high calcification rates in the light, lower net calcification rates in the dark from dissolution may not compromise daily calcification rates. However, if organismal dissolution in the dark is additive to sedimentary carbonate losses, reef dissolution may be amplified under OA and contribute to erosion of the Florida Reef Tract and other reefs that exhibit net dissolution.

Evaluating recycling fertilizers for tomato cultivation in hydroponics, and their impact on greenhouse gas emissions

Soilless culture systems offer an environmentally friendly and resource-efficient alternative to traditional cultivation systems fitting within the scheme of a circular economy. The objective of this research was to examine the sustainable integration of recycling fertilizers in hydroponic cultivation—creating a nutrient cycling concept for horticultural cultivation. Using the nutrient film technique (NFT), three recycling-based fertilizer variants were tested against standard synthetic mineral fertilization as the control, with 11 tomato plants (Solanum lycopersicum L. cv. Pannovy) per replicate (n = 4) and treatment: two nitrified urine-based fertilizers differing in ammonium/nitrate ratio (NH4+:NO3−), namely (1) “Aurin” (AUR) and (2) “Crop” (CRO); as well as (3) an organo-mineral mixture of struvite and vinasse (S+V); and (4) a control (NPK). The closed chamber method was adapted for gas fluxes (N2O, CH4, and CO2) from the root zone. There was no indication in differences of the total shoot biomass fresh matter and uptake of N, P and K between recycling fertilizers and the control. Marketable fruit yield was comparable between NPK, CRO and S+V, whereas lower yields occurred in AUR. The higher NH4+:NO3− of AUR was associated with an increased susceptibility of blossom-end-rot, likely due to reduced uptake and translocation of Ca. Highest sugar concentration was found in S+V, which may have been influenced by the presence of organic acids in vinasse. N2O emissions were highest in S+V, which corresponded to our hypothesis that N2O emissions positively correlate with organic-C input by the fertilizer amendments. Remaining treatments showed barely detectable GHG emissions. A nitrified urine with a low NH4+:NO3– (e.g., CRO) has a high potential as recycling fertilizer in NFT systems for tomato cultivation, and S+V proved to supply sufficient P and K for adequate growth and yield. Alternative cultivation strategies may complement the composition of AUR.

Genome-wide association studies of Ca and Mn in the seeds of the common bean (Phaseolus vulgaris L.)

SNP markers linked to genes controlling Ca and Mn uptake were identified in the common bean seeds using DArT-based association mapping (AM). The Ca concentration in the seeds varied between 475 and 3,100 mg kg−1 with an average of 1,280.9 mg kg−1 and the Mn concentration ranged from 4.87 to 27.54 mg kg−1 with a mean of 11.76 mg kg−1. A total of 19,204 SNP markers were distributed across 11 chromosomes that correspond to the haploid genome number of the common bean. The highest value of ΔK was determined as K = 2, and 173 common bean genotypes were split into two main subclusters as POP1 (Mesoamerican) and POP2 (Andean). The results of the UPGMA dendrogram and PCA confirmed those of STRUCTURE analysis. MLM based on the Q + K model identified a large number of markers-trait associations. Of the 19,204 SNPs, five (on Pv2, 3, 8, 10 and 11) and four (on Pv2, 3, 8 and 11) SNPs were detected to be significantly related to the Ca content of the beans grown in Bornova and Menemen, respectively in 2015. In 2016, six SNPs (on Pv1–4, 8 and 10) were identified to be significantly associated with the Ca content of the seeds obtained from Bornova and six SNPs (on Pv1–4, 8 and 10) from Menemen. Eight (on Pv3, 5 and 11) and four (on Pv2, 5 and 11) SNPs had a significant association with Mn content in Bornova in 2015 and 2016, respectively. In Menemen, eight (on Pv3, 5, 8 and 11) and 11 (on Pv1, 2, 5, 10 and 11) SNPs had a significant correlation with Mn content in 2015 and 2016, respectively.

Abstract 513: Emre Regulates the Mitochondrial Calcium Uniporter in vivo

Mitochondrial uptake of Ca 2+ plays critical roles in cardiac energy production as well as cell death. The mitochondrial calcium uniporter in mice and humans is a multi-protein complex that includes the channel-forming protein MCU and several other subunit proteins, including EMRE. EMRE is a single transmembrane protein that is conserved among metazoan species and is known to be essential for mitochondrial Ca 2+ uptake in cell culture. To investigate EMRE’s role in organismal physiology, we generated a mouse model of global germline EMRE deletion. We show that EMRE is indeed required for mitochondrial calcium uniporter function in isolated mitochondria from multiple tissues. Although the birth rate of Emre -/- mice is lower than expected by Mendelian genetics (~5-10% instead of ~25%), the mice that are born are viable and appear healthy. Oxygen consumption in isolated mitochondria and cells is not significantly affected by loss of EMRE, and similarly the mice do not exhibit overt metabolic impairment, even under strenuous exercise. No significant differences between Emre -/- and wild-type ( WT ) cardiac function at baseline and after isoproterenol stimulation are evident by echocardiography. Moreover, Emre -/ - hearts are not protected from ischemia/reperfusion injury in a Langendorff perfusion model (mean infarct area 61% in Emre -/- hearts; 57% in WT ). Collectively, these data and their similarities to results found via germline Mcu deletion demonstrate that EMRE is indeed essential for mitochondrial Ca 2+ uptake in vivo. Furthermore, we find evidence that EMRE protein expression is elevated in some mouse muscular dystrophy models, suggesting that modulation of EMRE levels may play a role in regulating uniporter activity in conditions of stress or disease. We therefore further explore whether and how EMRE expression changes with isoproterenol-induced cardiac hypertrophy in mice and in samples from human patients with heart failure. Understanding of how uniporter components such as EMRE can regulate MCU in a diseased state can inform better therapeutic strategies aimed at restoring mitochondrial metabolic homeostasis.

Potassium–calcium antagonistic interaction under tomato magnesium deficiency and magnesium fertiliser regulation in solar greenhouse

This study sought to clarify the antagonistic interactions of potassium (K) and calcium (Ca) to magnesium (Mg) under a deficiency of Mg in tomato. Tomato leaves and soil samples that had differing levels of Mg deficiency were collected to study the relationship between symptoms of Mg deficiency and contents of soil K and Ca. Four different Mg fertiliser treatments were conducted to analyse the regulation of Mg for soil K, Ca and Mg. The results showed the following: (1) The yield of tomatoes decreased significantly with an increase in Mg deficiency, and the yield of tomatoes with moderate (MD) and severe (SD) Mg deficiency decreased by 38.02% and 59.53%, respectively, compared with treatments without Mg deficiency (ND). (2) The cation saturation ratio of K+ (CSRK+) was significantly higher with MD and SD compared with ND, while the CSRMg2+ was lower. The soil K/Mg and Ca/Mg values were higher than the critical value of imbalance. (3) The soil exchangeable K, CSRK+, Ca/Mg and K/Mg under SD increased significantly when compared with that under ND. (4) The content of Mg in tomato leaves and its yield were significantly negatively correlated with soil exchangeable K, CSRK+ and K/Mg. (5) With the increase in application of Mg fertiliser, the soil exchangeable K content, K/Mg and CSRK+ decreased significantly, while the Ca/K increased. The soil exchangeable K content, K/Mg and CSRK+ with 90 kg/ha MgSO4 and 234 kg/ha K2O applied (M2K1 treatment) were the lowest among all treatments. (6) The yields of tomatoes and uptake of Ca and Mg increased as supply of Mg increased. (7). Reducing the application of K was a much more efficient way to decrease soil K/Mg and restore cation imbalance than providing Mg fertiliser in calcareous soil.

The modulation of sugarcane growth and nutritional profile under aluminum stress is dependent on beneficial endophytic bacteria and plantlet origin

Plant growth-promoting bacteria (PGPB) are claimed to not only improve plant fitness but also alleviate plant stress. In this study, we evaluated the effect of five PGPB strains on plantlet growth and nutrient and aluminum (Al) uptake under acid soil conditions characterized by low P and K nutrient availability and high metal and aluminum (Al) bioavailability, which may represent a stress condition for crop plants. The PGPB strains were inoculated in sugarcane plantlets produced by meristem tissue culture (MCPs) or one-bud stalks (O-BSPs) and cultivated in soil at 37% Al saturation and pH 4.0. Biomass accumulation and Al and nutrient content in roots and shoots were determined after 30 days of growth. Bacterial inoculation increased root and shoot biomass. However, the magnitudes of these increases were dependent on bacterial strain and plantlet origin. The inoculated plantlets exhibited increased Al content and shifts in Al allocation and calcium (Ca) and boron (B) content among different plant parts (root or shoot), and these changes also depended on plantlet origin and the inoculated strain. The higher Ca uptake of inoculated MCPs and higher B uptake of inoculated O-BSPs may have contributed to reducing the damage caused by excessive Al content. The beneficial microbes also caused changes in plant uptake of micronutrients and slightly reduced macronutrient content. Pseudomonas fluorescens (IAC/BECa 141), Kosakonia radicincitans (IAC/BECa 95), Paraburkholderia tropica (IAC/BECa 135) and Herbaspirillum frisingense (IAC/BECa 152) showed potential for alleviating Al stress in sugarcane plantlets.

NH4 fertilization increases susceptibility of sweet basil (Ocimum basilicum L.) to grey mould (Botrytis cinerea) due to decrease in Ca uptake

Sweet basil (Ocimum basilicum L.) is an economically important herbaceous annual plant of the Labiaceae family. One of the main pathogens of sweet basil is grey mould (Botrytis cinerea). Previous work showed that susceptibility to grey mould increased with increasing N availability. The purpose of this work is to determine the role N form and Ca in this phenomenon. First, data from previous experiments were reexamined in order to determine whether there was a correlation between shoot Ca and basil plant susceptibility to B. cinerea. Then, basil plants were grown in a complete randomized design with 12 treatments and 5 repetitions in which N concentration, N type, and Ca concentration were varied. Plants were harvested 7 times, and shoot Ca and N were measured. Cuttings and full plants were inoculated with B. cinerea in order to determine their susceptibility to grey mould. We found that increases in N availability only increased the susceptibility of the basil plants to grey mould when the N was provided as a mix of NO3 and NH4, whereas in treatments where N was provided solely as NO3, N availability had no effect on plant susceptibility. Furthermore, we found that NH4 inhibited Ca accumulation, and shoot Ca concentration was negatively correlated to plant susceptibility. Taken together, this shows that N availability per se did not increase basil susceptibility to B. cinerea, rather it was the increase in NH4 fertilization which caused a reduction in shoot Ca which in turn was responsible for this effect.

Effects of Acute Exercise and Training on the Sarcoplasmic Reticulum Ca2+ Release and Uptake Rates in Highly Trained Endurance Athletes.

Little is presently known about the effects of acute high-intensity exercise or training on release and uptake of Ca2+ by the sarcoplasmic reticulum (SR). The aims here were to characterize this regulation in highly trained athletes following (1) repeated bouts of high-intensity exercise and (2) a period of endurance training including high-intensity sessions. Eleven cross-country skiers (25 ± 4 years, 65 ± 4 mL O2⋅kg−1⋅min–1) performed four self-paced sprint time-trials (STT 1-4) lasting ≈ 4 min each (STT 1–4) and separated by 45 min of recovery; while 19 triathletes and road cyclists (25 ± 4 years, 65 ± 5 mL O2⋅kg−1⋅min–1) completed 4 weeks of endurance training in combination with three sessions of high-intensity interval cycling per week. Release (μmol⋅g–1 prot⋅min–1) and uptake [tau (s)] of Ca2+ by SR vesicles isolated from m. triceps brachii and m. vastus lateralis were determined before and after STT 1 and 4 in the skiers and in m. vastus lateralis before and after the 4 weeks of training in the endurance athletes. The Ca2+ release rate was reduced by 17–18% in both limbs already after STT 1 (arms: 2.52 ± 0.74 to 2.08 ± 0.60; legs: 2.41 ± 0.45 to 1.98 ± 0.51, P < 0.0001) and attenuated further following STT 4 (arms: 2.24 ± 0.67 to 1.95 ± 0.45; legs: 2.13 ± 0.51 to 1.83 ± 0.36, P < 0.0001). Also, there was a tendency toward an impairment in the SR Ca2+ uptake from pre STT1 to post STT4 in both arms and legs (arms: from 22.0 ± 3.7 s to 25.3 ± 6.0 s; legs: from 22.5 ± 4.7 s to 25.5 ± 7.7 s, P = 0.05). Endurance training combined with high-intensity exercise increased the Ca2+ release rate by 9% (1.76 ± 0.38 to 1.91 ± 0.44, P = 0.009), without altering the Ca2+ uptake (29.6 ± 7.0 to 29.1 ± 8.7 s; P = 0.98). In conclusion, the Ca2+ release and uptake rates by SR in exercising limbs of highly trained athletes declines gradually by repetitive bouts of high-intensity exercise. We also demonstrate, for the first time, that the SR Ca2+ release rate can be enhanced by a specific program of training in highly trained athletes, which may have important implications for performance parameters.