Inorganic Phosphorus Research Articles

Quantitatively unveiling the role of coastal wetlands in regulating eutrophication and enhancing water environmental capacity

Human activities have intensified the global challenge of coastal eutrophication. Recently, water resource managers have encountered difficulties in formulating precise pollutant reduction strategies to mitigate coastal eutrophication. Despite the recognized importance of coastal wetlands and pollution sources in influencing coastal nutrient levels, accurately quantifying their impact remains difficult. To address this challenge, this study introduces a novel approach for optimizing water environmental capacity. A coupled model integrating hydrodynamics, water quality, and wetland nutrient mechanisms was developed to simulate the spatio-seasonal distribution of water, sediment, and vegetation nutrients in a semi-enclosed bay (Liaodong Bay, China) and a large-scale coastal wetland (Liaohe estuary wetland, China). Model parameters and simulation results were calibrated and validated using extensive long-term field investigations and laboratory experiments. The average root mean square errors between simulated and observed values for all validation points were as follows: 0.80mgL-1, 0.53mgL-1, 0.08mgL-1, 6.70μgL-1, and 0.50μgL-1 for dissolved oxygen, chemical oxygen demand, dissolved inorganic nitrogen, dissolved inorganic phosphorus, and chlorophyll-a, respectively. The total nitrogen (TN) and total phosphorus (TP) in the sediment were 0.10gkg-1 and 0.05gkg-1, respectively. For Suaeda salsa, the TN and TP were 2.91gkg -1 and 0.08gkg -1, respectively. For Phragmites australis, the TN and TP were 114.22gkg -1 and 6.21gkg -1, respectively. The results suggest that excessive river discharge and a stable residual circulation structure contribute to the persistent eutrophication in Liaodong Bay. The Liaohe estuary wetland enhances the environmental capacity of dissolved inorganic nitrogen and dissolved inorganic phosphorus in Liaodong Bay to 271±31tyr-1 and 8±1tyr-1, respectively, accounting for 1.8±0.2% and 1.3±0.2% of their respective environmental capacities. The reduction in dissolved inorganic nitrogen concentration is significant, with a maximum decrease of 0.17mgL-1. The maximum contributions of atmospheric deposition and aquaculture wastewater to dissolved inorganic nitrogen concentration are 0.08mgL-1 and 0.03mgL-1, respectively, with higher contributions in spring and summer than in fall and winter. These findings highlight the critical role of coastal wetlands in mitigating eutrophication and underscore the need for spatio-seasonal water management programs. This work serves as a model for effectively reducing global coastal pollution emissions.

Different elemental stoichiometries of Fe‐limited Trichodesmium when grown under inorganic and organic phosphorus sources

AbstractTrichodesmium spp. is a colonial diazotrophic cyanobacterium found in the oligotrophic (sub)tropical oceans, where its distribution is strongly regulated by the availability of phosphorus and iron. The bulk carbon : nitrogen : phosphorus elemental composition of phytoplankton has previously been shown to depart from classical “Redfield” values under nutrient‐limitation conditions. We hypothesized that the abundance of intracellular metabolites and the extended Redfield ratios of Trichodesmium, including a range of trace elements, are variable in response to conditions of phosphorus and iron limitation that are found in the ocean. To test this, we grew Trichodesmium under trace metal–controlled conditions, where phosphorus was supplied as either dissolved inorganic phosphorus (DIP) or dissolved organic phosphorus (DOP) from iron depleted to elevated levels. We found that the steady‐state extended Redfield ratios of Trichodesmium under the iron‐depleted condition was (C106N15.82P0.62)1000Fe2.26Zn2.37Mn1.68Cu0.68Ni0.31Mo0.42Co0.03 for the DIP treatment where Trichodesmium was under iron limitation, and (C106N13.89P0.49)1000Fe3.38Zn2.51Mn0.97Cu0.52Ni0.42Mo0.33Co0.03 for the DOP treatment where Trichodesmium was under iron–phosphorus co‐limitation. Mean steady‐state cellular iron : carbon in the DIP treatment (iron limited) was only 50% of that in the control treatment, while zinc : carbon was elevated twofold. The average extended Redfield ratios following recovery from iron limitation was (C106N16.8P0.7)1000Fe4.41Zn1.44Mn1Cu0.52Ni0.19Mo0.3Co0.03 for the DIP and (C106N15.9P0.73)1000Fe7.36Zn2.24Mn1.08Cu0.71Ni0.63Mo0.38Co0.02 for the DOP treatment. No significant changes were observed in the carbon‐normalized abundance of targeted metabolites produced by Trichodesmium, under the different treatments. These results suggest Trichodesmium employs different strategies to cope with iron/phosphorus limitation, which is reflected in its extended Redfield ratios.

Pelletized Organomineral vs. Inorganic Nitrogen and Phosphorus Fertilizers: Impact on Wheat Nutritional Status, Productivity, and Grain Quality

Pelletized Organomineral vs. Inorganic Nitrogen and Phosphorus Fertilizers: Impact on Wheat Nutritional Status, Productivity, and Grain Quality

Diversity and Functional Roles of Root-Associated Endophytic Fungi in Two Dominant Pioneer Trees Reclaimed from a Metal Mine Slag Heap in Southwest China

The utilization of fast-growing, economically valuable woody plants with strong stress resistance, such as poplar and willow, to revegetate severely metal-contaminated mine tailings not only offers a productive and profitable use of abandoned polluted soil resources but also facilitates the phytoremediation of these polluted soils. This study examines the diversity and functional roles of endophytic fungi naturally colonizing the roots of an artificially established Populus yunnanensis forest and the naturally reclaimed pioneer species Coriaria sinica on an abandoned tailing dam in southwest China. Culture-independent analyses revealed that the root systems of both plant species were abundantly colonized by arbuscular mycorrhizal fungi and endophytic fungi, forming rich and diverse endophytic fungal communities predominantly represented by the genera Ilyonectria, Tetracladium, Auricularia, and unclassified members of Helotiales. However, the composition of root endophytic fungal communities differed significantly between the two plant species. Using a culture-dependent approach, a total of 192 culturable endophytic fungal strains were isolated from the roots. The dominant genera included Cadophora, Cladosporium, Cyphellophora, and Paraphoma, most of which were previously identified as dark septate endophytes (DSE). Six representative DSE strains were selected for further study, and significant cadmium tolerance and various plant growth-promoting traits were observed, including the solubilization of insoluble inorganic and organic phosphorus, indole-3-acetic acid (IAA) production, and siderophore synthesis. In greenhouse experiments, inoculating two DSE strains mitigated the inhibitory effects of metal-polluted tailing soil on the growth of P. yunnanensis. This was achieved by reducing heavy metal uptake in roots and limiting metal translocation to the above-ground tissues, thereby promoting plant growth and adaptability. Our findings suggest that as plants reclaim metal-polluted tailings, root-associated endophytic fungal communities also undergo natural succession, playing a critical role in enhancing the host plant’s tolerance to stress. Therefore, these restored root-associated fungi, particularly DSE, are essential functional components of the root systems in plants used for tailing reclamation.

Lifetime minimally invasive assessment of iron in the pig liver

Microelements are an integral part of the mammalian body, and their content in organs and tissues is associated with other components of a complex biological system. Based on this, it is feasible to evaluate the concentration of specific chemical elements within the structures of the body in non-invasive or minimally invasive methods. The meat and by-products of farm animals serve as a readily assimilateable source of iron, which is one of the reasons for potentially defining the quality of agricultural products in conditions of widespread iron deficiency. Landrace pigs were raised in standard conditions at an industrial complex located in the Altai Territory in order to fatten up to a live weight of 100 kg. Venous blood was collected using the acute method from the jugular vein in accordance with the principles of asepsis and pre-analytical guidelines. The hematologic and biochemical examination of the blood and serum of animals was performed by apparatus. After slaughter, liver samples were collected, and the method of atomic emission spectral analysis using inductively coupled plasma on iCAP-PRO equipment (Thermo Fisher Scientific) was used to estimate the iron level in them. To manipulate the data, Microsoft Office Excel software and RStudio data analysis environment version 2023.03.1 (RStudio, PBC) were employed. For regression analysis, the least squares approach was used. The model was fitted using a stepwise selection of predictors in both directions using the Akaike information criterion, Bayesian information criterion, and adjusted coefficient of determination. The linear regression assumptions were evaluated. The final regression model used for determining iron levels in pig liver contains mean hemoglobin content in erythrocytes, hemoglobin, and serum inorganic phosphorus as predictors. There is no evidence that there is multicollinearity between the predictors of the final model. The proposed model satisfies the requirements for a normal distribution of residuals, the absence of their correlation, and influential observations. The proposed multiple regression model has the capability to estimate iron levels in pig liver in vivo for various purposes.

Isolation and characterization of plant growth-promoting rhizobacteria (PGPR) from eelgrass Zostera marina rhizosphere: implications for bioremediation

Plant growth-promoting rhizobacteria (PGPR) play a crucial role in enhancing plant growth. However, investigations into the presence and function of PGPR in seagrass rhizospheres remain relatively limited. In this study, we isolated 45 strains of PGPR from Zostera marina rhizospheres and assessed their functional attributes. Additionally, we evaluated the performance of these candidate strains under varying environmental conditions, such as temperature, salinity, and pH. Out of the 45 analyzed strains, 6 were found to possess the nifH gene; some strains also exhibited the ability to solubilize inorganic phosphorus, with dissolved phosphorus content ranging widely from 14.6 to 393.9 mg l-1. Eleven strains demonstrated indole-3-acetic acid production, with yields spanning from 16.3 to 42.8 mg l-1. Siderophores and ammoniated proteins were produced by 32 and 20 strains, respectively. Notably, 5 PGPR strains (F65, G84, G85, G86, and I109) displayed multiple growth-promoting properties along with strong adaptability to a wide range of physicochemical conditions. This study highlights the potential reservoir of PGPR in the eelgrass rhizosphere and provides significant implications for utilizing these bacteria to enhance the success rate of restoring degraded seagrass meadows.

The role of microorganisms in phosphorus cycling at river-lake confluences: Insights from a study on microbial community dynamics

River-lake confluences are key zones in the river-lake network, essential for managing contaminant transport and transformation. However, the role of biogeochemical transformations, particularly in phosphorus (P) dynamics, has been underexplored. As a result, this study looks into the dynamics of microbial communities and how important microbes are to the cycling of P. It was revealed that microorganisms contribute differently to phosphorus cycling in different hydraulic regions. Regions with higher-velocity and finer sediment showed increased microbial diversity and enhanced capabilities for organic phosphorus (OP) mineralization and inorganic phosphorus (IP) solubilization due to lower bio-available P (bio-P) concentrations. In areas characterized by flow deflection (FD), flow stagnation (FST), and flow separation (FSE), distinct P fraction distributions were observed: Total phosphorus (TP) and bio-P were found to be more abundant in the FST and FD regions, but residual phosphorus (Res-P) and calcium phosphorus (Ca-P) were more prevalent in the FSE region. Sediment characteristics, including P species like aluminum-phosphorus (Al-P), OP, iron-associate phosphorus (BD-P), and sediment mid-diameter (D50), significantly influence microbial community composition. These results improve our comprehension of the distribution of microbial community distribution and its role in the phosphorus cycle at river-lake confluence, providing useful provide valuable information for managing river-lake confluences and protecting aquatic ecosystems.

Different patterns of bacterioplankton in response to inorganic and organic phosphorus inputs in freshwater lakes - a microcosmic study

Phosphorus (P) is a limiting factor in fresh waters and is also the main cause of water eutrophication and deterioration, However, the practical effect of elevated P level on bacterioplankton is less evaluated. In this study, we investigated the bacterioplankton in a 96 hours microcosm experiment with P additions in two forms (organic/inorganic P, OP/IP) and three levels (final conc., 0.040, 0.065 and 0.125 g/L), aiming to find out the response pattern of bacterioplankton in coping with the increasing P levels. Results showed a more dramatic change of water properties and bacterioplankton between P forms (OP and IP) than among the addition levels, and a more remarkable effect of OP addition than the IP. Both OP and IP treatments significantly decreased the water pH, dissolved oxygen (DO), Electrical Conductivity (EC), Nitrate Nitrogen (NO3--N) and Total Organic Carbon (TOC), and reduced the α-diversity of bacterioplankton and relative abundance of Cyanobacteria, but increased the abundance of Proteobacteria. The IP addition decreased Actinobacteria abundance (especially for HgcI) and showed higher denitrification potentials, while the OP addition depressed the Bateroidota and exhibited lowed methylotrophic functions, but such trends decreased with increasing addition concentrations. The network analysis showed that both IP and OP additions increased the proportion of positively correlated edges and reduced the network complexity and stability, but the OP network was more stable than the IP network. The study clarifies the response pattern of bacterioplankton to the P input with different forms and levels, and deepens our understanding of the eutrophication process, which provides a scientific basis for the management and control of freshwater lakes facing eutrophication.

The Pb capture mechanism of soil prophylactic agents prepared from phosphorus tailings and the influence of phosphorus speciation on its slow-release mechanism

This research activated phosphorus tailings to prepare a high‑phosphorus core (HPC) for multi-species composite slow-release heavy metal soil prophylactic agents (MCP), aiming to extend the slow-release period of MCP and enhance the efficiency of Pb stabilization. During the preparation of HPC, the proportion of non-apatitic inorganic phosphorus (NAIP) and apatite phosphorus (AP) continuously decreased with increasing polymerization temperature. At 400 °C, polyphosphates (PP) began to form, reaching 74.26 % at 600 °C. Initially, the rapidly soluble NAIP remained the major component of HPC, but the proportion of AP increased with higher polymerization temperatures, reaching 40.8 % at 600 °C. After 120 days of cultivation with four MCPs (MCP 300-21, MCP 400-12, MCP 500-14, MCP 600-14), the total soil phosphorus (TSP), soil organic matter (SOM), and Pb stabilization capacity of the cultivated soil showed significant improvements, reaching maximum values of 2.39 mg/g, 38.16 mg/g, and 45.4 mg/g, respectively, which are 9.9, 4.4, and 5.9 times higher than those of the CK soil. KEGG (Kyoto Encyclopedia of Genes and Genomes) functional prediction analysis indicated that MCPs contribute directly or indirectly to the forms and chemical stability of Pb by stimulating soil physiological and biochemical processes. This research proposes a novel approach for using phosphates in soil heavy metal management strategies and provides new insights into the mechanisms of heavy metal stabilization in soil using environmental functional materials.

Harmful Microalgae Exhibit Broad Environmental Adaptability in High-Salinity Area Across the Dafengjiang River Estuary.

Harmful algal blooms (HABs) often occur in estuaries due to their unique environmental heterogeneity, posing significant environmental and human health risks. However, there is limited understanding of the community composition and community-level change points (thresholds) of harmful microalgae in subtropical estuaries. This study explored harmful microalgae community structure and thresholds in the Dafengjiang River estuary using a metabarcoding approach. The results revealed 63 harmful microalgae species, and major species included Guinardia flaccida, Prorocentrum cordatum, Thalassiosira punctigera, Pseudo-nitzschia galaxiae and T. gravida. Nonparametric change-point analysis and threshold indicator taxa analysis (TITAN) showed threshold responses of harmful microalgae community structure to ammonium (57.5-60 μg·L-1), total phosphorus (27.8-28.5 μg·L-1) and dissolved inorganic phosphorus (14.5-28 μg·L-1) along the salinity gradient. Wider environmental thresholds were also found in hypersaline areas. Additionally, Pyrodinium bahamense, Pfiesteria piscicida, Skeletonema tropicum and T. punctigera were sensitive to environmental changes and thus could be used as bioindicators. Overall, our study unveiled diverse abrupt transitions of harmful microalgal communities, providing a risk assessment for human health and ecological safety in subtropical estuary ecosystems.

The microRNA399d-PHOSPHATE2 module alters rice sensitivity to rice ragged stunt virus by manipulating phosphate uptake.

Rice (Oryza sativa L.) production frequently faces threats from biotic and abiotic stressors, with rice ragged stunt virus (RRSV) as a substantial biotic factor. The relationship between inorganic phosphorus (Pi) content and susceptibility to RRSV is crucial yet poorly understood. This study investigates how phosphorus metabolism influences rice resistance to RRSV, focusing on genetic manipulations that modulate this relationship. The RRSV infection increased phosphate (Pi) content in the aerial parts of rice plants by enhancing Pi uptake and transport. Furthermore, the upregulation of microRNA399d (miR399d) and the suppression of its target gene OsPHOSPHATE2 (OsPHO2) enhanced Pi accumulation, increasing rice susceptibility to RRSV infection. Additionally, elevated Pi levels, which are associated with altered ROS dynamics, reduced ROS activity and potentially dampened the plant's innate immune response to viral infection. The miR399d-PHO2 module was identified as pivotal in mediating phosphate uptake and influencing susceptibility to RRSV through modulations in the phosphorus and ROS pathways. This study shed light on the regulatory mechanisms of phosphorus nutrition in rice, revealing a critical interaction between phosphorus metabolism, ROS dynamics, and viral defense. The findings suggest potential strategies for manipulating Pi levels to enhance plant resistance against viruses, opening avenues for agricultural improvements and disease management in rice.

Physiological changes in the regulation of calcium and phosphorus utilization that occur after the onset of egg production in commercial laying hens.

At the onset of egg production, physiological changes governing calcium and phosphorus utilization must occur to meet demands for medullary bone formation and eggshell mineralization. The objective of this study was to identify these changes and determine if they are influenced by dietary supplementation with 1α-hydroxycholecalciferol (AlphaD3™, Iluma Alliance). Commercial laying hens fed either a control or AlphaD3-supplemented diet beginning at 18 weeks of age were sampled at 18 (n = 8) and 31 weeks (n = 8/diet) to evaluate mRNA expression associated with calcium and phosphorus utilization in kidney, shell gland, ileum, and liver, circulating vitamin D3 metabolites, and bone quality parameters in humerus, tibia, and keel bone. Though diet did not heavily influence gene expression at 31 weeks, several significant differences were observed between 18- and 31-week-old hens. Heightened sensitivity to hormones regulating calcium and phosphorus homeostasis was observed at 31 weeks, indicated by increased parathyroid hormone receptor 1, calcium-sensing receptor, calcitonin receptor, and fibroblast growth factor 23 receptors in several tissues. Increased renal expression of 25-hydroxylase and vitamin D binding protein ( DBP ) at 31 weeks suggests kidney participates in local vitamin D3 25-hydroxylation and DBP synthesis after egg production begins. Biologically active 1,25(OH)2D3 was higher at 31 weeks, with correspondingly lower inactive 24,25(OH)2D3. Increased expression of plasma membrane calcium ATPase 1 and calbindin in kidney, shell gland, and ileum suggests these are key facilitators of calcium uptake. Elevated renal inorganic phosphorus transporter 1 and 2 and sodium-dependent phosphate transporter IIa at 31 weeks suggests increased phosphorus excretion following hyperphosphatemia due to bone breakdown for eggshell formation. Diet did influence bone quality parameters. Bone mineral density in both humerus and tibia was higher in AlphaD3-supplemented hens at 31 weeks. Tibial bone mineral content increased between 18 and 31 weeks, with AlphaD3-supplemented hens increasing more than control hens. Moreover, control hens exhibited diminished tibial breaking strength at 31 weeks compared to hens at 18 weeks, while AlphaD3-supplemented hens did not. Together, these results indicate supplementation with AlphaD3 enhanced bone mineralization during the medullary bone formation period and elucidate the adaptive pathways regulating calcium and phosphorus utilization after the onset of lay.

Exploring plant growth promotion by actinomycetes from Phyllostachys viridiglaucescens rhizosphere

Aim. Actinomycetes are one of the main groups of rhizospheric bacteria involved in plant growth and health enhancement. This makes them promising candidates for the development of biopreparations in agriculture. The aim of this study was to explore the plant growth promoting actinobacteria isolated from P. viridiglaucescens rhizosphere. Methods. Standard microbiological and statistical methods were used. Results. 20 % of the isolates were found to be potentially capable of siderophore synthesis; 12 % – solubilized inorganic phosphorus; 26 % – assimilated atmospheric nitrogen; and 55 % – produced auxin-related substances. A significant part of the isolates produced auxin-related substances at a concentration of up to 20 μg/ml. The majority of isolates had at least one plant growth promoting property. However, among the actinomycetes, there were representatives that combined two or more properties. The strain Streptomyces sp. Pv 4-122.1 had a significant positive impact on the radish germination of the “Krakivianka” variety, while another actinomycete strain – Pv 4-204 – exhibited potential herbicidal activity. Conclusions. A significant part of the isolates has a high potential for the production of plant growth promoting compounds. Individual isolates can serve as the basis for biopreparations both to enhance plant growth and with herbicidal effects.

Soil phosphorus fractionations as affected by cropping systems in the central mid-hills region of Nepal.

Soil plays a critical role as the primary reservoir of phosphorus (P) in terrestrial ecosystems. Sequential fractionation has been extensively utilized to gain insights into the characteristics and dynamics of soil P. However, there is a knowledge gap regarding the different P pools in Nepalese soils. Therefore, this study aimed to investigate the impact of cropping systems on soil P fractions in the central mid-hills of Nepal. The study focused on four cropping systems: vegetable, fruit, rice, and maize-based systems, which exhibited variations in nutrient management, topography, and cropping intensity. A total of 240 soil samples (60 samples from each cropping system) were collected from multiple sites within the central mid-hill region. Standard analytical methods were used to determine the general parameters of the soils, while the sequential fractionation method was employed to assess the organic and inorganic P pools. The results indicated that the effect of cropping systems on soil pH, calcium carbonate (CaCO3) content, and the proportion of sand, silt, and clay was not statistically significant in terms of general parameters. However, significant differences were observed among the different cropping systems in organic matter (OM), electrical conductivity (EC), cation exchange capacity (CEC), and available phosphorus. Similarly, in terms of inorganic phosphorus fractions, loosely bound P (LB-P), aluminum bound P (Al-P), iron bound P (Fe-P), and reductant soluble P (RS-P) were significantly affected, while calcium bound P (Ca-P) did not show a significant difference. Furthermore, in terms of organic phosphorus fractions, labile organic P (L-Po), fluvic acid organic P (FA-Po), and non-labile organic P (NL-Po) exhibited significant differences, whereas moderately labile organic P (ML-Po) and humic acid organic P (HA-Po) did not show a significant difference. Additionally, reductant soluble P showed a significant difference, while total P did not differ significantly. The vegetable-based system exhibited higher levels of the majority of P fractions, followed by the fruit-based, maize-based, and rice-based systems. These findings emphasize the importance of considering cropping systems and their response to different phosphorus pools, as this knowledge can contribute to the development of improved soil phosphorus management strategies and promote sustainable agricultural practices in the region.

Control of inorganic and organic phosphorus molecules on microbial activity, and the stoichiometry of nutrient cycling in soils in an arid, agricultural ecosystem

Background The dynamics of carbon (C), nitrogen (N), and phosphorus (P) in soils determine their fertility and crop growth in agroecosystems. These dynamics depend on microbial metabolism, which in turn depends on nutrient availability. Farmers typically apply either mineral or organic fertilizers to increase the availability of nutrients in soils. Phosphorus, which usually limits plant growth, is one of the most applied nutrients. Our knowledge is limited regarding how different forms of P impact the ability of microbes in soils to produce the enzymes required to release nutrients, such as C, N and P from different substrates. Methods In this study, we used the arable layer of a calcareous soil obtained from an alfalfa cropland in Cuatro Cienegas, México, to perform an incubation experiment, where five different phosphate molecules were added as treatments substrates: three organic molecules (RNA, adenine monophosphate (AMP) and phytate) and two inorganic molecules (calcium phosphate and ammonium phosphate). Controls did not receive added phosphorus. We measured nutrient dynamics and soil microbial activity after 19 days of incubation. Results Different P molecules affected potential microbial C mineralization (CO2-C) and enzyme activities, specifically in the organic treatments. P remained immobilized in the microbial biomass (Pmic) regardless of the source of P, suggesting that soil microorganisms were limited by phosphorus. Higher mineralization rates in soil amended with organic P compounds depleted dissolved organic carbon and increased nitrification. The C:N:P stoichiometry of the microbial biomass implied a change in the microbial community which affected the carbon use efficiency (CUE), threshold elemental ratio (TER), and homeostasis. Conclusion Different organic and inorganic sources of P affect soil microbial community structure and metabolism. This modifies the dynamics of soil C, N and P. These results highlight the importance of considering the composition of organic matter and phosphate compounds used in agriculture since their impact on the microbial activity of the soil can also affect plant productivity.

The effect of local injections of a vitamin d receptor activator into the parathyroid glands on the level of parathyroid hormone and mineral metabolism in patients with secondary hyperparathyroidism in chronic kidney disease

Aim: to assess the dynamics of laboratory parameters (total calcium, inorganic phosphorus, albumin, and alkaline phosphatase levels) and parathyroid hormone (PTH) concentrations after administrating local injections of vitamin D receptor activators into the parathyroid glands of patients with secondary hyperparathyroidism in chronic kidney disease. The intial PTH concentration ranged from 300 to 600 pg/ml. This range was chosen to explore a more active strategy for managing the disease at its early stages and preventing the induction and progression of cardiovascular complications associated with secondary hyperparathyroidism.Methods: the study included 48 patients diagnosed with end-stage of chronic kidney disease, who were treated in the nephrology and dialysis department. The main group consisted of 34 patients who received two consecutive injections of a vitamin D receptor activator (Paricalcitol) into the most enlarged and technically accessible parathyroid gland under ultrasound guidance. The control group included 14 patients who continued with conservative treatment due to technical infeasibility of performing the injections. Effectiveness was assessed by comparing laboratory parameters before the intervention and six months after the injections in the main group, and among patients continuing standard medical therapy for secondary hyperparathyroidism.Results: the results showed a statistically significant reduction in parathyroid hormone levels after 3 and 6 months of treatment. In the control group, which continued to receive standard drug therapy, PTH and blood phosphate levels continued to rise. No undesirable effects or complications, such as hypocalcemia, bleeding, allergic reactions, and recurrent laryngeal nerve paralysis, were not observed throughout the observation period.Conclusion: this research confirms the efficacy of local injections of vitamin D receptor activators (Paricalcitol) in reducing PTH levels without significant complications or changes in calcium levels. This method could be employed to correct and prevent secondary hyperparathyroidism complications in early stages among patients with end-stage chronic kidney disease, offering a safer and more effective treatment option.

Development and characterization of lpa1 and lpa2-based low phytate double mutants in maize for enhancing the nutritional quality of food and feed

Phytic acid (PA), an anti-nutritional factor hampers the nutritional value of maize-based food by reducing the bioavailability of zinc and iron. Low phytate maize is key for addressing poor micronutrient bioavailability. Here, we developed low phytic acid double mutants (lpa1/lpa2) in maize by crossing lpa1 and lpa2-based near-isogenic lines (NILs) in seven genetic backgrounds. Genotypic selections for lpa1 and lpa2 genes in the F2 population revealed segregation ratios of 9:3:3:1 for double mutants and 3:1 for single mutants. Newly developed double mutants along with single mutants and wild types, were field-evaluated for two seasons. Wide genetic variation was observed for PA, inorganic phosphorus (Pi), grain yield, and agro-morphological traits, with negligible G×E interactions. PA concentration of lpa1/lpa2 (1.73 mg/g) was significantly (P <0.05) lower than wild types (2.92 mg/g), lpa1 (1.86 mg/g), and lpa2 (2.05 mg/g) lines. The double mutants revealed more prominent PA reduction (41 %) than single mutants, lpa1 (36 %) and lpa2 (30 %) compared to wild types. Additionally, the double mutants recorded comparable performance to wild types for grain yield and other agro-morphological traits. This study illustrated the potential of double mutants over lpa-based single mutants in lowering the anti-nutritional effects and enhancing the nutritional value of maize grains.

Biochar and wood vinegar altered the composition of inorganic phosphorus bacteria community in saline-alkali soils and promoted the bioavailability of phosphorus

As an important part of the ecosystem, saline-alkali soils are in urgent need of efficient and environmentally friendly soil conditioners. Biochar and wood vinegar are regarded as organic soil improvement and plant growth regulators to improve soil physicochemical properties and promote crop growth. However, the mechanism of how inorganic phosphorus bacteria increase phosphorus when biochar and wood vinegar applied to saline-alkali soils is not clear. Herein, the present study was designed to investigate the effects of biochar and wood vinegar with different rates on physicochemical properties of saline-alkali soils and inorganic phosphorus bacteria diversities and to discuss the mechanism of biochar and wood vinegar on available phosphorus by pot experiments. The application of biochar and wood vinegar exhibited an effect on the decrease in pH and salt contents and the increase in soil porosity, soil nutrients, and hundred-grain weight of rice. The 600 kg ha−1 biochar and 1800 kg ha−1 wood vinegar group showed the most significant increment in available phosphorus, alkaline phosphatase, acid phosphatase, and neutral phosphatase activities, with the increases of 49.24%, 40.35%, 48%, and 149%, respectively. The 600 kg ha−1 biochar and 1200 kg ha−1 wood vinegar group significantly enhanced microbial biomass phosphorus concentrations by 41.29%. Moreover, biochar and wood vinegar shifted inorganic phosphorus bacteria composition structure and promoted its diversities, more so at a higher rate of wood vinegar application. The dominant species of inorganic phosphorus bacteria were Proteobacteria, Gammaproteobacteria, Alphaproteobacteria, Pseudomonas, and Rhizobium in saline-alkali soils. The Alphaproteobacteria and Hydrogenophaga were the key microorganisms reducing pH and salt contents and increasing available phosphorus contents in saline-alkali soils. In conclusion, the application of biochar and wood vinegar was a useful strategy to improve saline-alkali soils.

Exploring novel potential of mycosynthesized magnetic nanoparticles for phosphatase immobilization and biological activity

Among different microbes, fungi are proficient candidates for the extracellular synthesis of iron nanoparticles. For biogenic synthesis of iron nanoparticles, a thermophilic mould Myceliophthora thermophila BJTLRMDU7 was used in this study. Mycogenic magnetic nanoparticles were used for phosphatase immobilization and therapeutic applications such as antimicrobial and antimalarial activity. Firstly, the phosphatase was immobilized on biogenic iron nanoparticles with an efficiency of >56 %. Immobilized enzyme was optimally active at 60 °C and pH 5. Immobilized phosphatase was recycled using external magnetic field up to 4th cycle retaining >50 % activity. The immobilized phosphatase efficiently released inorganic phosphate from different flours such as wheat, maize and gram at 37 °C and 60 °C. There was continuous increase in the release of inorganic phosphorus from all samples with incubation time at 37 °C and slight reduction at 60 °C. These nanoparticles showed the effective antimicrobial activity against Bacillus subtilis, Escherichia coli and Myceliophthora thermophila. Further, the synthesized iron nanoparticles showed antimalarial potential against Plasmodium falciparum. Biogenic nanoparticles did not exhibit hemolytic activity and cytotoxicity. Therefore, biogenic iron nanoparticles could be used as a suitable matrix for immobilization of enzymes and safe therapeutics.

Promoting effects of ferric ions on Microcystis aeruginosa growth and arsenate accumulation and reduction at different phosphorus environments

The effects of different dissolved organic phosphorus (DOP) associated with distinct iron conditions (iron deficient (dFe), ferric ions (Fe3+), and colloidal iron (CFe)) on algal growth and arsenate (As(V)) metabolism were systematically evaluated and compared in Microcystis aeruginosa. Two chemical forms of DOP (D-glucose-6-phosphate (GP) and phytic acid (PA)), as well as dissolved inorganic phosphorus (DIP), were employed as distinct phosphorus environments. The results revealed that As(V) metabolism of M. aeruginosa was more influenced by different phosphorus forms than by different iron conditions. Conversely, the release of microcystins in the media was found to be significantly more affected by the different phosphorus forms than by the iron conditions. Moreover, DOP was observed to promote arsenic (As) biotransformation, particularly the efflux of methylated As from a single algal cell, whereas DIP was found to primarily facilitate As(V) accumulation in algae. The total As metabolism amount per algal cell under PA was observed to be five times that observed under DIP and GP. The influence of iron conditions on the synthesis of algal metabolites was notable, as evidenced by the metabolites identified in algae of aliphatic (δ 1.28–1.68), humic acid-like and aromatic protein-like substances through 1H-NMR spectra and three-dimensional excitation-emission matrix fluorescence spectroscopy analysis. This impact was particularly notable at Fe3+ conditions, due to the role of Fe3+ as a micronutrient with highly bioavailable forms, which enhanced the synthesis of organic compounds in algae and promoted algal growth. Consequently, Fe3+ could inhibit As accumulation under DIP but promote it under DOP. The obtained results facilitate a more comprehensive understanding of the combined role of different phosphorus forms and iron conditions in algal bloom outbreaks and As(V) metabolism.