Search Results (791)

Calcium ameliorates salt-related growth defects in plants. The objective of this study was to determine whether supplying calcium through a seed enrichment technique enhances the germinability and early growth of timothy (Phleum pratense L.) under saline conditions. For seed enrichment, timothy seeds were soaked in CaCl₂ solutions at concentrations of 50 mM or 100 mM for 24 h at room temperature. Seeds treated with distilled water served as the control. Under distilled water conditions, germination rates among the seeds showed minimal variation, approximately 95% on average. However, in a 200 mM NaCl environment, the germination rate of the control seeds significantly decreased to 25%, while the germination rates of the Ca-enriched seeds remained high, exceeding 86%. Additionally, the Ca-enriched seeds germinated more quickly than the control seeds. When plants were grown with distilled water, the total dry matter weights did not differ significantly among the treatment types. However, under salt stress with 100 mM NaCl, the plants derived from Ca-enriched seeds thrived and exhibited higher dry matter weights compared to the control plants. The Ca-enriched seeds contained more soluble sugars and demonstrated higher catalase activity than the control seeds, and their corresponding plants accumulated less sodium under salt stress compared to the control plants. Seed enrichment is an effective technique for supplying calcium to timothy, and a concentration of 50 mM of CaCl₂ in the treatment solution is sufficient to achieve salt tolerance. Full article

The precipitation of minerals, in particular carbonates, is a widespread phenomenon in all ecosystems, where it assumes a high relevance both from a geological and biogeochemical standpoint. Most carbonate rocks are of biological origin and made in an aquatic environment. In particular, bioprecipitation of carbonates is believed to have started in the Mesoproterozoic Era, thanks to a process often driven by photosynthetic microorganisms. Nevertheless, an important contribution to carbonate precipitation is also due to the metabolic activity of heterotrophic bacteria, which is not restricted to specific taxonomic groups or to specific environments, making this process a ubiquitous phenomenon. In this framework, the relationship between carbonatogenic microorganisms and other living organisms assumes a particular interest. This study aims to isolate and identify the culturable heterotrophic bacterial component associated with the coenosarc of Corallium rubrum in order to evaluate the occurrence of strains able to precipitate carbonates. In particular, the study was focused on the identification and characterisation of bacterial strains isolated from a coral coenosarc showing a high carbonatogenic capacity under laboratory conditions. Samples of C. rubrum were taken in the coastal waters of three Italian regions. The concentration of the aerobic heterotrophic microflora colonising C. rubrum coenosarc samples spanned from 3 to 6∙10⁶ CFU/cm². This variation in microbial populations colonising the C. rubrum coenosarc, spanning over 6 orders of magnitude, is not mirrored by a corresponding variability in the colony morphotypes recorded, with the mean being 5.1 (±2.1 sd). Among these bacteria, the carbonatogenic predominant species was Staphylococcus equorum (93% of the isolates), whereas Staphylococcus xylosus and Shewanella sp. accounted only for 3% of isolates each. All these strains showed a remarkable capacity of precipitating calcium carbonate, in the form of calcite crystals organised radially as well crystalised spherulites (S. equorum) or coalescing spherulites (Shewanella sp.). S. xylosus only produced amorphous precipitates of calcium carbonate. All bacterial strains identified were positive both for the production of urease and carbon anhydrase in vitro at 30 °C. It seems that they potentially possess the major biochemical abilities conducive to Ca²⁺ precipitation, as they showed in vitro. In addition, all our carbonatogenic isolates were able to hydrolyse the phytic acid calcium salt and then were potentially able to induce precipitation of calcium phosphates also through such a mechanism. Full article

Thermodynamic factors (supersaturation of substances that form crystals) and kinetic factors (heterogeneous nucleants and crystallization inhibitors) affect the formation of crystals and stones in the urinary tract. We studied the effect of five different polyhydroxycarboxylic acids and phytate on the formation of calcium oxalate crystals in artificial urine. All tested molecules are known to inhibit the crystallization of this calcium salt, and to also form complexes with calcium ions. Considering the typical concentration of polyhydroxycarboxylic acids in urine (similar to that of the calcium ion) and their ability to inhibit crystallization, their most important effect is the capacity to complex calcium—a thermodynamic effect. For phytate and its metabolites, which are present in concentrations much lower than that of the calcium ion, the most important effect is as a crystallization inhibitor—a kinetic effect. Among the five polyhydroxycarboxylic acids examined here, hydroxycitrate had the strongest complexing capacity, and the addition of phytate to hydroxycitrate led to greater inhibition of crystallization. Therefore, because oral consumption of hydroxycitrate does not increase the urinary pH, it is likely that the combined consumption of hydroxycitrate and phytate can provide certain benefits for patients with increased risk of developing calcium oxalate stones. We also discussed the effects of these different molecules on the different calcium oxalate stones, including papillary calcium oxalate monohydrate stones, cavity calcium oxalate monohydrate stones, calcium oxalate dihydrate stones, and mixed calcium oxalate dihydrate/hydroxyapatite stones. Full article

Titanium alloys are frequently subjected to surface treatments to enhance their biocompatibility and corrosion resistance in biological environments. Plasma electrolytic oxidation (PEO) is an environmentally friendly electrochemical technique capable of forming oxide layers characterized by high corrosion resistance, biocompatibility, and strong adhesion to the substrate. In this study, the PEO process was performed using a low-melting-point ternary eutectic electrolyte composed of Ca(NO₃)₂–NaNO₃–KNO₃ (41–17–42 wt.%) with the addition of ammonium dihydrogen phosphate (ADP). The use of this electrolyte system enables a reduction in the operating temperature from 280 to 160 °C. The effects of applied voltage from 200 to 400V, current frequency from 50 to 1000 Hz, and ADP concentrations of 0.1, 0.5, 1, 2, and 5 wt.% on the growth of titanium oxide composite coatings on a Ti-6Al-4V substrate were investigated. The incorporation of Ca and P was confirmed by phase and chemical composition analysis, while scanning electron microscopy (SEM) revealed a porous surface morphology typical of PEO coatings. Corrosion resistance in Hank’s solution, evaluated via Tafel plot fitting of potentiodynamic polarization curves, demonstrated a substantial improvement in electrochemical performance of the PEO-treated samples. The corrosion current decreased from 552 to 219 nA/cm², and the corrosion potential shifted from −102 to 793 mV vs. the Reference Hydrogen Electrode (RHE) compared to the uncoated alloy. These findings indicate optimal PEO processing parameters for producing composite oxide coatings on Ti-6Al-4V alloy surfaces with enhanced corrosion resistance and potential bioactivity, which are attributed to the incorporation of Ca and P into the coating structure. Full article

The use of chloride-based deicing salts, particularly sodium chloride (NaCl) and calcium chloride (CaCl₂), is a common practice in cold regions for maintaining road safety during winter. However, the accumulation of salt residues in adjacent soils poses serious environmental threats, including reduced pH, increased electrical conductivity (EC), disrupted soil structure, and plant growth inhibition. This study aimed to evaluate the combined effect of activated carbon (AC) and Pennisetum alopecuroides, a salt-tolerant perennial grass, in alleviating salinity stress under deicer-treated soils. A factorial greenhouse experiment was conducted using three fixed factors: (i) presence or absence of Pennisetum alopecuroides, (ii) deicer type (NaCl or CaCl₂), and (iii) activated carbon mixing ratio (0, 1, 2, 5, and 10%). Soil pH, EC, and ion concentrations (Na⁺, Cl⁻, Ca²⁺) were measured, along with six plant growth indicators. The results showed that increasing AC concentrations significantly increased pH and reduced EC and ion accumulation, with the 5% AC treatment being optimal in both deicer systems. Plant physiological responses were improved in AC-amended soils, especially under CaCl₂ treatment, indicating less ion toxicity and better root zone conditions. The interaction effects between AC, deicer type, and plant presence were statistically significant (p < 0.05), supporting a synergistic remediation mechanism involving both adsorption and biological uptake. Despite the limitations of short-term controlled conditions, this study offers a promising phytomanagement strategy using natural adsorbents and salt-tolerant plants for sustainable remediation of salt-affected soils in road-adjacent and urban environments. Full article

Microplastics (MPs) have emerged as pervasive environmental contaminants due to their widespread presence across various ecosystems, including their use in single-use plastic food ware and table salt dispensers. This issue coincides with the presence of heavy metals in water sources in Doha, Qatar. Fourier Transform Infrared (FTIR) analysis revealed that the plastic plate and spoon were composed of polyolefin, with the spoon exhibiting additional peaks that indicated oxidation or the presence of additives. Thermogravimetric Analysis (TGA) revealed that the spoon exhibited higher thermal stability, retaining approximately 10% of its mass at 700 °C, than the plate, which retained 2%, indicating the presence of complex additives or contamination. MPs in food-grade salt samples were verified through filtration and Fourier Transform Infrared (FTIR) Spectroscopy, identifying polymers such as polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). These MPs likely stem from exposure to packaging or environmental contaminants. FTIR spectra confirmed the integrity of the polymers after treatment. Inductively Coupled Plasma–Optical Emission Spectroscopy (ICP-OES) analysis revealed varying levels of heavy metals in bottled and tap water, with notable findings including detectable arsenic and lead in both, higher calcium and magnesium in bottled water, and the presence of copper present in tap water only, highlighting potential health and infrastructure-related concerns. These results highlight the possible risks associated with exposure to MPs and heavy metals from everyday products and water sources, underscoring the need for enhanced regulatory oversight and safer material choices to ensure protection. Full article

Based on an integrated analysis, this study summarized the current status of soil quality in Yantai apple orchards, developed a multivariate regulation model for key soil physicochemical properties, and proposed optimized fertilization strategies to improve soil quality in the region. The study analyzed the physicochemical properties of the topsoil (0–30 cm) in 19 representative apple orchards across Yantai, including indicators like pH, organic matter (OM), major nutrient ions, and salinity indicators, using standardized measurements and multivariate statistical methods, including descriptive statistics analysis, frequency distribution analysis, canonical correlation analysis, stepwise regression equation analysis, and regression fit model analysis. The results demonstrated that in apple orchards across the Yantai region, reductions in pH were significantly mitigated under the combined increased OM and exchangeable calcium (Ca). Exchangeable potassium (EK) rose in response to the joint elevation of OM and available nitrogen (AN), and AN was also positively influenced by EK, while OM also exhibited a promotive effect on Olsen phosphorus (OP). Furthermore, Ca increased with higher pH. AN and EK jointly contributed to the increases in electrical conductivity (EC) and chloride ions (Cl), while elevated exchangeable sodium (Na) and soluble salts (SS) were primarily driven by EK. Accordingly, enhancing organic and calcium source fertilizers is recommended to boost OM and Ca levels, reduce acidification, and maintain EC within optimal limits. By primarily reducing potassium’s application, followed by nitrogen and phosphorus source fertilizers, the supply of macronutrients can be optimized, and the accumulation of Na, Cl, and SS can be controlled. Collectively, the combined analysis of soil quality status and the multivariate regulation model clarified the optimized fertilization strategies, thereby establishing a solid theoretical and practical foundation for recognizing the necessity of soil testing and formula fertilization, the urgency of improving soil quality, and the scientific rationale for nutrient input management in Yantai apple orchards. Full article

Cardiovascular disease and hypertension are major global health challenges, and increasing dietary salt intake is a known contributor. Emerging evidence suggests that excessive salt exposure during pregnancy may impact fetal development, yet its effects on early embryogenesis remain poorly understood. In this study, we used zebrafish (Danio rerio) embryos as a model to investigate the developmental and molecular consequences of high-salt exposure during early vertebrate development. Embryos subjected to elevated salt levels exhibited delayed hatching, reduced heart rates, and significant alterations in gene expression profiles. Transcriptomic analysis revealed over 4000 differentially expressed genes, with key disruptions identified in calcium signaling, MAPK signaling, cardiac muscle development, and vascular smooth muscle contraction pathways. These findings indicate that early salt exposure can perturb crucial developmental processes and signaling networks, offering insights into how prenatal environmental factors may contribute to long-term cardiovascular risk. Full article

Non-conventional water sources (saline and brackish water) are viable options for crop cultivation. Current salt-tolerance research largely focuses on Na⁺ and Cl⁻, while other ions in these waters remain ill-understood. Synthetic seawater was a representative of saline and brackish water in a Design of Experiments (DoE) treatment design used to evaluate the effects of factors [synthetic seawater (0, 15, 30, or 45%, v/v, Instant Ocean^®), total inorganic nitrogen (0, 14, or 28 mM; 1 NH₄⁺:8 NO₃⁻ ratio), potassium (0, 9, or 21 mM), calcium (0, 2, or 5 mM), silicon (0, 0.03, or 0.09 mM) and zinc (0, 0.05, or 2 mM)] on seedlings for two varieties of Brassica juncea [‘Carolina Broadleaf’ (CB) and ‘Florida Broadleaf’ (FB)] using a hydroponic assay. In 30–45% synthetic seawater, 0.09 mM of silicon or 2 mM of calcium alleviated salt stress. In FB, 0.04–0.06 mM of silicon was optimal for the production of new leaves. The CB variety showed greater production of new leaves with 0.09 mM of silicon and 28 mM of potassium. Potassium and calcium are components of seawater, and a sodium chloride assay would not account for their interactions without a multivariate approach to evaluate salt tolerance. The seedling assay identified factors and established criteria for larger-scale harvest experiments. Full article

Inorganic nanoparticles (NPs) have been synthesised via mixing and coalescence of droplets containing precursors and entrained by gaseous streams. The droplets have been generated by ultrasonic aerosolisation of two different liquid phases, each containing the respective reagent. The as-produced NPs are trapped by mixing with a liquid phase in a Venturi nozzle, acting simultaneously as a collector and concentrator of the solid nanosized phase produced. Commercial electrically powered ultrasonic aerosolising devices have been adapted to atomise salt solutions characterised by high electrical conductivity. This process allowed the synthesis of calcium carbonate NPs with an average diameter in the range of (34–52) nm, according to the concentration of precursors in the aerosolised phases. This closed-loop method of synthesis, where neither capping agents were used nor demanding operating conditions were adopted, can represent a safe and viable eco-friendly technique for NP production free of undesirable compounds, as required for pharmaceutical preparations and theranostic uses. Full article

Soluble adenylyl cyclase (sAC) is molecularly and biochemically distinct from other mammalian nucleotidyl cyclases. It is uniquely regulated directly by bicarbonate (HCO₃⁻) and calcium (Ca²⁺) ions and is responsive to physiologic fluctuations in levels of its substrate, adenosine triphosphate (ATP). Our initial in vitro biochemical studies suggested two mechanisms for HCO₃⁻-dependent elevation of sAC activity: increasing catalytic rate and relieving inhibition observed in the presence of supraphysiological levels of substrate, ATP. Structural and mutational studies revealed that HCO₃⁻ increases catalytic rate via the disruption of a salt bridge that facilitates productive interactions with the substrate. Here, we demonstrate that the HCO₃⁻ stimulation observed under supraphysiological ATP concentrations is due to the mitigation of ATP-dependent acidification. Therefore, we conclude that the sole physiologically relevant mechanism of HCO₃⁻ regulation of sAC is through its pH-independent effect facilitating productive substrate binding to the catalytic site. Full article

Salinity has significant impacts on crops, a problem that is exacerbated under climate change conditions. For this reason, research is focused on possible ways to mitigate the impacts by adapting cultivation methods such as administering appropriate materials or formulations to plants. Therefore, this study investigated the effects of calcium (Ca²⁺) supplementation on the growth, physiology, and chemical composition of pomegranate plants (Punica granatum L. cv. ‘Wonderful’) grown under salinity stress. Young self-rooted plants were cultivated in pots containing a sand/perlite (1:1) mixture and irrigated with Hoagland’s nutrient solution amended with NaCl (0, 60, or 120 mM) and CaCl₂·2H₂O (0 or 10 mM). Salinity significantly reduced the fresh and dry weight of aboveground tissues; photosynthetic performance; chlorophyll content; and potassium (K), calcium (Ca), and magnesium (Mg) concentrations, particularly under high NaCl levels. Sodium (Na) accumulation increased in all plant parts, while nitrogen (N), manganese (Mn), and zinc (Zn) concentrations were elevated in basal leaves. Calcium supplementation mitigated several of these adverse effects, especially under moderate salinity. It helped maintain leaf biomass, supported K⁺ retention in roots, partially improved chlorophyll concentration, and limited Na⁺ accumulation in certain tissues. However, Ca²⁺ application did not consistently reverse the negative impacts of severe salinity (120 mM NaCl), and in some cases, interactions between Ca²⁺ and other nutrients such as Mg²⁺ were antagonistic. These findings confirm the inherent salt tolerance of pomegranate and demonstrate that calcium plays a partially protective role under salinity, particularly at moderate stress levels. Further research is needed to optimize Ca²⁺ use in saline agriculture and enhance sustainable cultivation of pomegranate in salt-affected soils. Full article

With water availability being one of the world’s major challenges, this study aims to propose a Zero Liquid Discharge (ZLD) system for treating saline effluents from an urban wastewater treatment plant (UWWTP), thereby supplementing into the existing water cycle. The system, which employs membrane (nanofiltration and reverse osmosis) and thermal technologies (multi-effect distillation evaporator and vacuum crystallizer), has been installed and operated in Cyprus at Larnaca’s WWTP, for the desalination of the tertiary treated water, producing high-quality reclaimed water. The nanofiltration (NF) unit at the plant operated with an inflow concentration ranging from 2500 to 3000 ppm. The performance of the installed NF90-4040 membranes was evaluated based on permeability and flux. Among two NF operation series, the second—operating at 75–85% recovery and 2500 mg/L TDS—showed improved membrane performance, with stable permeability (7.32 × 10⁻¹⁰ to 7.77 × 10⁻¹⁰ m·s⁻¹·Pa⁻¹) and flux (6.34 × 10⁻⁴ to 6.67 × 10⁻⁴ m/s). The optimal NF operating rate was 75% recovery, which achieved high divalent ion rejection (more than 99.5%). The reverse osmosis (RO) unit operated in a two-pass configuration, achieving water recoveries of 90–94% in the first pass and 76–84% in the second. This setup resulted in high rejection rates of approximately 99.99% for all major ions (Cl⁻, Na⁺, Ca²⁺, and Mg²⁺), reducing the permeate total dissolved solids (TDS) to below 35 mg/L. The installed multi-effect distillation (MED) unit operated under vacuum and under various inflow and steady-state conditions, achieving over 60% water recovery and producing high-quality distillate water (TDS < 12 mg/L). The vacuum crystallizer (VC) further concentrated the MED concentrate stream (MEDC) and the NF concentrate stream (NFC) flows, resulting in distilled water and recovered salts. The MEDC process produced salts with a purity of up to 81% NaCl., while the NFC stream produced mixed salts containing approximately 46% calcium salts (mainly as sulfates and chlorides), 13% magnesium salts (mainly as sulfates and chlorides), and 38% sodium salts. Overall, the ZLD system consumed 12 kWh/m³, with thermal units accounting for around 86% of this usage. The RO unit proved to be the most energy-efficient component, contributing 71% of the total water recovery. Full article

This study evaluated the effects of supplementing early-lactation Holstein cows with rumen-protected omega-3 fatty acids (calcium salts) on productive and reproductive performance. Thirty-six multiparous cows were randomly assigned to one of two treatments from 21 ± 2 days before calving to 105 ± 5 days in milk (DIM): a Control group (C) or an Omega-3-supplemented group (O-3), receiving a blend of linseed and fish oil (60:40). Both groups were fed isoenergetic diets, with ground corn as the control supplement. Total dry matter and net energy intake did not differ between treatments. A treatment-by-time interaction was observed for milk yield, with cows in the O-3 group producing more milk than controls at specific time points. Additionally, O-3 cows had higher overall protein yield and improved feed efficiency. No differences were found in body weight, BCS, glucose, insulin, IGF-1, or urea concentrations, but a tendency toward higher plasma NEFA and BHBA concentrations and lower energy balance was observed in the O-3 group. Supplementation increased plasma cholesterol and progesterone concentrations and was associated with a higher proportion of cows being pregnant at 130 DIM. These findings suggest that omega-3 supplementation may improve specific aspects of lactational performance and reproductive efficiency without compromising metabolic status. Full article

Microbially induced calcium carbonate precipitation (MICP) has emerged as a research focus in concrete crack remediation due to its environmental compatibility and efficient mineralization capacity. The hypersaline conditions of seawater (average 35 g/L NaCl) and alkaline environments (pH 12) within concrete cracks pose significant challenges to the survival of mineralization-capable microorganisms. To enhance microbial tolerance under these extreme conditions, this study employed a laboratory adaptive evolution strategy to successfully develop a Sporosarcina pasteurii strain demonstrating tolerance to 35 g/L NaCl and pH 12. Comparative analysis of growth characteristics (OD₆₀₀), pH variation, urease activity, and specific urease activity revealed that the evolved strain maintained growth kinetics under harsh conditions comparable to the parental strain under normal conditions. Subsequent evaluations demonstrated the evolved strain’s superior salt–alkali tolerance through enhanced enzymatic activity, precipitation yield, particle size distribution, crystal morphology, and microstructure characterization under various saline–alkaline conditions. Whole-genome sequencing identified five non-synonymous mutated genes associated with ribosomal stability, transmembrane transport, and osmoprotectant synthesis. Transcriptomic profiling revealed 1082 deferentially expressed genes (543 upregulated, 539 downregulated), predominantly involved in ribosomal biogenesis, porphyrin metabolism, oxidative phosphorylation, tricarboxylic acid (TCA) cycle, and amino acid metabolism. In concrete remediation experiments, the evolved strain achieved superior performance with 89.3% compressive strength recovery and 48% reduction in water absorption rate. This study elucidates the molecular mechanisms underlying S. pasteurii’s salt–alkali tolerance and validates its potential application in the remediation of marine engineering. Full article