Inorganic Forms Research Articles

New horizons for selenium in animal nutrition and functional foods.

Selenium (Se), one of the indispensable nutrients for both human health and animal growth, participates in various physiological functions, such as antioxidant and immune responses and metabolism. The role of dietary Se, in its organic and inorganic forms, has been well documented in domestic animals. Furthermore, many feeding strategies for different animals have been developed to increase the Se concentration in animal products to address Se deficiency and even as a potential nutritional strategy to treat free radical-associated diseases. Nevertheless, studies on investigating the optimum addition of Se in feed, the long-term consequences of Se usage in food for animal nutrition, the mechanism of metallic Se nanoparticle (SeNP) transformation in vivo, and the nutritional effects of SeNPs on feed workers and the environment are urgently needed. Starting from the absorption and metabolism mechanism of Se, this review discusses the antioxidant role of Se in detail. Based on this characteristic, we further investigated the application of Se in animal health and described some unresolved issues and unanswered questions warranting further investigation. This review is expected to provide a theoretical reference for improving the quality of food animal meat as well as for the development of Se-based biological nutrition enhancement technology.

A weak cold eddy influencing nitrogen form in the western part of the South China Sea

Nitrogen is an essential element for all life and it exhibits in three major dissolved inorganic chemical forms to participate in the marine nitrogen cycling. In this study, a transect through the weak cold eddy was undertaken near Xisha Islands of the South China Sea (SCS) in summer of 2009. There was a trend of decreased temperature inside the eddy, while PO4 and NO3 increased in comparison to outside the eddy The primary nitrite maximum (PNM) was found in the depth of about 50 m in the in-situ samples. Phytoplankton excretion has advantage of PNM formation and maintenance in the euphotic layer. Additionally, nitrate anomaly (N*) were positive, which implies that nitrogen fixation occurs in the surface water in the studying period. These results indicate that cold eddy has influence on regulating inorganic nitrogen biogeochemistry in the studying area during sampling period.

Assessing the risk of human exposure to bioaccessible arsenic from total diet through market food consumption in Chengdu, China.

To assess the daily intake of total arsenic (tAs) and arsenic speciation and their potential health risks, different food groups, including vegetables, rice, meat, viscera, freshwater fish, and seafood from Chengdu, China were analyzed. The concentrations of tAs ranged from 41.3 to 1185μgkg-1 with a median of 238μgkg-1, and 26.0% of tAs in the food groups was of inorganic toxic form. The median concentration of As(V) in rice (184 ± 21.6μgkg-1) was approximately 2 to 6 times higher than those in other food groups. The bioaccessible inorganic arsenic (iAs) concentrations of the food items obtained from the local markets of Chengdu ranged from 1.07 to 24.6μgkg-1 (mean of 6.04μgkg-1). Rice contributed toward the largest amount of daily iAs intake (66.2%). The mean daily iAs intake from vegetable, meat and viscera contributed 10.7%, 12.5% and 6.04% of total iAs intake, respectively. The actual concentration of arsenic in the food exposed to the human body depends on oral bioaccessible fraction. The oral bioaccessibility estimated daily intake (μg kg-1 bw d-1) of tAs and iAs for the residents of Chengdu was 0.32 and 0.16. Health risk assessments carried out based on bioaccessible iAs concentrations showed that the food items were safe for consumption from the iAs perspective.

Form of dietary selenium affects mRNA encoding interferon-stimulated and progesterone-induced genes in the bovine endometrium and conceptus length at maternal recognition of pregnancy.

Widespread regions of the southeast United States have soils, and hence forages, deficient in selenium (Se), necessitating Se supplementation to grazing cattle for optimal immune function, growth, and fertility. We have reported that supplementation with an isomolar 1:1 mix (MIX) of inorganic (ISe) and organic (OSe) forms of Se increases early luteal phase (LP) concentrations of progesterone (P4) above that in cows on ISe or OSe alone. Increased early LP P4 advances embryonic development. Our objective was to determine the effects of the form of Se on the development of the bovine conceptus and the endometrium using targeted real-time PCR (qPCR) on day 17 of gestation, the time of maternal recognition of pregnancy (MRP). Angus-cross yearling heifers underwent 45-d Se-depletion then repletion periods, then at least 90 d of supplementation (TRT) with 35 ppm Se per day as either ISe (n = 10) or MIX (n = 10). Heifers were inseminated to a single sire after detected estrus (day 0). On day 17 of gestation, caruncular (CAR) and intercaruncular (ICAR) endometrial samples and the developing conceptus were recovered from pregnant heifers (ISe, n = 6 and MIX, n = 6). qPCR was performed to determine the relative abundance of targeted transcripts in CAR and ICAR samples, with the expression data subjected to one-way ANOVA to determine TRT effects. The effect of TRT on conceptus development was analyzed using a one-tailed Student's t-test. When compared with ISe-treated heifers, MIX heifers had decreased (P < 0.05) abundance of several P4-induced and interferon-stimulated mRNA transcripts, including IFIT3, ISG15, MX1, OAS2, RSAD2, DGAT2, FGF2 in CAR and DKK1 in ICAR samples and tended (P ≤ 0.10) to have decreased mRNA abundance of IRF1, IRF2, FOXL2, and PGR in CAR samples, and HOXA10 and PAQR7 in ICAR samples. In contrast, MIX-supplemented heifers had increased (P < 0.05) mRNA abundance of MSTN in ICAR samples and an increase in conceptus length (ISe: 17.45 ± 3.08 cm vs. MIX: 25.96 ± 3.95 cm; P = 0.05). Notably, myostatin increases glucose secretion into histotroph and contributes to advanced conceptus development. This advancement in conceptus development occurred in the presence of similar concentrations of serum P4 (P = 0.88) and whole blood Se (P = 0.07) at MRP.

Form of dietary selenium affects mRNA encoding cholesterol biosynthesis and immune response elements in the early luteal phase bovine corpus luteum.

Widespread regions of the southeast United States have soils, and hence forages, deficient in selenium (Se), necessitating Se supplementation to grazing cattle for optimal immune function, growth, and fertility. We have reported that supplementation with an isomolar 1:1 mix (MIX) of inorganic (ISe) and organic (OSe) forms of Se increases early luteal phase (LP) progesterone (P4) above that in cows on ISe alone. Increased early LP P4 advances embryonic development. Our objective was to determine the effect of form of Se on the transcriptome of the early LP corpus luteum (CL) with the goal of elucidating form of Se-regulated processes affecting luteal steroidogenesis and function. Non-lactating, 3-yr-old Angus-cross cows underwent 45-d Se-depletion, then repletion periods, and then at least 90 d of supplementation (TRT) with 35 ppm Se/d as either ISe (n = 5) or MIX (n = 5). CL were then recovered on day 7 of the estrous cycle, total RNA isolated, and the effect of TRT on the luteal transcriptome evaluated using bovine gene 1.0 ST arrays (Affymetrix, Inc., Santa Clara, CA). The abundance of transcripts in each CL was subjected to one-way ANOVA using Partek Genomic Suite software to determine TRT effects. Microarray analysis indicated a total of 887 transcripts that were differentially expressed and functionally annotated, with 423 and 464 up- and down-regulated (P < 0.05) in MIX vs. ISe CL, respectively. Bioinformatic analysis (Ingenuity Pathway Analysis) revealed the top TRT-affected canonical pathways to include seven specific to cholesterol biosynthesis and two to inflammatory responses. Results from the microarray analysis were corroborated by targeted real-time PCR. MIX CL had increased (P < 0.05) abundance of transcripts regulating cholesterol biosynthesis including DHCR7, DHCR24, and CYP51A1 (fold changes of 1.65, 1.48, and 1.40, respectively), suggesting MIX-induced increases in P4 to be due, in part, to increased availability of substrate to luteal cells. In addition, MIX CL had increased (P < 0.05) abundance of immune-response transcripts including C1QC, FAS, ILR8B, and IL1R1 (fold changes of 2.30, 1.74, 1.66, and 1.63, respectively). SREBF1 mRNA was also increased (1.32-fold, P < 0.05) in the MIX CL, which increases cholesterol synthesis and stimulates IL1B, linking effects of form of supplemental Se (TRT) on cholesterol biosynthesis and immune function in the CL.

Selenium Adsorption as Influenced by Different Anions in some Middle Euphrates Soils

Adsorption Selenium (Se) levels in soils may be changed by a variety of variables. such as compecting anion. Investigated adsorption behavior for two top soil different properties, aiming to describe selenium adsorption in selected centrial Iraq soils. (Awfi) Samples were collected comprising clayed soil, Which Se adsorption tests were performed on the samples. After a 72-hour reaction with increasing concentrations of Se(0-400 µg mL-1) added as Na2SeO4, adsorption was measured. In the presence of Sulphate and Phosphate, which are usually applied in an inorganic form to soils. Soil properties affected adsorption capability of se, i.e. Se adsorped amount were higher for Awfi soils. The adsorption of Se on soils increased as the amount of Se supplied increased, both in the presence and absence of cometic anions. Se adsorption followed Langmuir’s and Freundlich’s equations. There are no competing anions in the absence of any, adsorption maxima of Se 87.719 μg g-1 The data from K and XM adequately reflected the adsorption of Se in the examined soils. This was ascribed to the existence of higher concentrations of competing anions, particularly sulphate and phosphate.

An analysis of the content changes in free and combinative forms of organic selenium in radish sprouts cultivated with solutions of selenoamino acids

Selenium (Se) is critical for human health, but human intake of Se is often inadequate. Organic forms of dietary Se are considered safe and more bioavailable than inorganic forms. Along with a generally high nutritional value, sprouts are sensitive to Se treatment. This study used selenomethionine and methylselenocysteine solutions to cultivate Se-enriched sprouts under an optimized hydroponic condition. Content change and transformations of the selenoamino acids were analyzed by a developed HPLC-ESI-MS/MS method. Uptake of both selenomethionine and methylselenocysteine was dose-dependent and involved active transport and passive diffusion, as demonstrated by the respiratory and aquaporin inhibition assays. Passive diffusion played a dominant role. Free methylselenocysteine was the predominant form in samples. Selenomethionine and methylselenocysteine were capable of mutual transformation. Moreover, the selenoprotein generation was associated with the increasing Se concentration of the culture solutions. The results provided scientific references for the efficient utilization of organic Se in sprouts.

Dietary Copper Deficiency Leads to Changes in Gene Expression Indicating an Increased Demand for NADH in the Prefrontal Cortex of the Rat's Brain.

Copper is an essential element to brain cells as it is a cofactor and a structural component of various enzymes involved in energy metabolism pathways. Accumulating evidence points to the pivotal role of copper deficiency in neurodegeneration resulting from impaired copper homeostasis. Despite the indisputable role of copper in mitochondrial respiration, its homeostasis regulation in the brain tissue remains unclear. The assessment of changes in the expression of genes encoding key pathways of energy metabolism can greatly benefit further studies exploring copper’s role in neurodegeneration. Using a rat model, we investigate whether the replacement of the inorganic form of copper with metallic nanoparticles containing copper or complete deprivation of copper from the diet have an impact on the expression of genes involved in energy metabolism in the prefrontal cortex of the rats’ brain. Herein, we indicate that removing inorganic copper from the normal standard diet or the replacement with copper nanoparticles can lead to programmed energy metabolism changes. It can be recognized that some of these changes indicate an increased demand for NADH in the prefrontal cortex of the rat’s brain, probably as a result of adaptation effect.

The effect of feed supplementation with zinc glycine chelate and zinc sulphate on hepatic proteome profiles in chickens

One of the most important factors influencing production outcomes in poultry farming is optimal balancing of the feed ration in terms of macro- and micronutrients. Zinc is an essential trace element that increases metabolic processes. The natural components of poultry feed do not contain sufficient zinc, or even contain numerous factors limiting its absorption, which necessitates supplementation of feed with this element. The purpose of the study was to identify proteins synthesized in the liver of chickens fed a diet supplemented with zinc in the form of sulphates and a glycine chelate; to determine differences in the expression of these proteins; and to describe the peptide profile of hepatocytes in chickens. A total of 900 1-day-old male Ross 308 chickens, assigned to 5 dietary treatments, were used in the experiment. The experimental groups received a basal diet + zinc in inorganic and organic form and a phytase supplement. The material for analysis comprised samples of liver and serum. The zinc concentration in serum and tissues was determined by flame atomic absorption spectrometry. The liver lipid profile was estimated by the gravimetric method. A complete proteomic analysis of liver samples included protein separation by two-dimensional electrophoresis, plotting of a protein map illustrating the proteome of the liver, statistical analysis, and identification of statistically significant proteins by MALDI-TOF mass spectrometry. The results of the study demonstrate that organic and inorganic forms of zinc used as feed additives for chickens not only affect the concentration of this element in the liver, but also have a systemic effect by altering the expression of proteins. A complete proteomic analysis of liver samples made it possible to identify eight proteins whose expression depended on the type of supplement added to the feed. The results clearly indicate that bioavailable zinc administered in the form of glycine chelates affects processes stimulating synthesis of ApoA-I, β2-MG, protein-disulphide-isomerase, neuroblast differentiation-associated protein AHNAK, and alpha-N-acetylgalactosaminide alpha-2,6-sialyltransferase 1 in the tissues of chickens. Supplementation of poultry feed with zinc in both sulphate and chelated form caused changes in the expression of the protein yippee-like 4 and histone H1.1. A high concentration of prolyl endopeptidase protein in the liver of birds receiving zinc sulphate was also observed. In conclusion, supplementation of poultry feed with zinc chelates modifies the expression profiles of proteins involved in intracellular transport, the cell cycle, metabolism, and the immune response.

Effects of Vermicompost Substrates and Coconut Fibers Used against the Background of Various Biofertilizers on the Yields of Cucumis melo L. and Solanum lycopersicum L.

Vermicompost has been promoted as a viable substrate component owing to its physicochemical properties, nutrient richness, and status as an excellent soil improver. It is considered the best organic fertilizer and is more eco-friendly than chemical fertilizers. Plant-growth-promoting microorganisms (PGPMs) are defined as plant biofertilizers that improve nutritional efficiency—that is, they transform nutrients within substrates from organic to inorganic forms, making them available for plants. The main objective of this research study is to evaluate the effects of the application of three PGPM microbial consortia on different mixtures of organic substrates based on vermicompost (V) and coconut fiber (CF) on two different horticultural crops. We performed a yield analysis and drainage nutrient tests and determined the plant nutritional status and enzymatic activity in organic substrates based on the two crops, Cucumis melo L. and Solanum lycopersicum L. A multivariate analysis of variance and principal component analysis was conducted using substrate types and PGPMs as factors. Differences (p &lt; 0.05) in yield, dehydrogenase activity, the nutrient concentrations in a petiole sap, and drainage were observed at 30, 60, 75, and 90 days after transplant. PGPMs such as Trichoderma sp. and plant-growth-promoting rhizobacteria (PGPR) in organic substrates (40V + 60CF) can significantly improve the nutritional status of plants for use in organic soilless container agriculture. Biofertilization with PGPMs and suitable mixtures of organic substrates together with aqueous extracts (tea) of vermicompost, as nutrient solutions applied by fertigation, has allowed us to achieve an adequate level of production through environmentally friendly techniques. The results obtained allowed us to affirm that it was possible to replace conventional fertilization using no chemical products and ensure adequate crop nutrition by supplying main macronutrients with organic sources and biofertilizers.

Effect of Dietary Organic and Inorganic Sulfur on the Performance of Coccidiosis Vaccine Challenged Broiler Chickens.

Simple SummaryCoccidiosis is a parasitic disease in poultry that causes significant economic losses. It is understood that natural or synthetic antioxidants including plant extracts, vitamin E, and selenium have been proved to lessen the gut severity of Eimeria infection in chickens. Sulfur is an essential element and exhibits beneficial activities including parasitic, antioxidant, and anti-inflammatory. These functional features of sulfur might play a role in inhibiting the negative effect of chicken coccidiosis and, if proved, sulfur could be used as an anticoccidial agent. We tested dietary sulfur of both organic and inorganic forms with beneficial antioxidant properties in a mild coccidiosis disease broiler chicken model.The objective of this study was to evaluate the effects of dietary sulfur from either organic (methyl sulfonyl methane, MSM) or inorganic (sodium sulfate, SS) sources on the growth performance of broiler chickens challenged against a high-dose coccidiosis vaccine. A total of 320 day-old Ross 308 broiler chicks were randomly placed into 32 pens of 10 birds each (keeping 16 pens/control group and 8 pens/treatment group until 21 days post-hatch) and reared for 28 days. The experimental diets were formulated by mixing a corn and soybean meal-based control diet with MSM or SS. At 21 days post-hatch, half (n = 8) of the control and all of the sulfur-added diet-fed (i.e., MSM and SS) groups were challenged with a 30-fold dose of a commercially available Eimeria vaccine (Livacox® T coccidiosis vaccine). Unchallenged control chicks (n = 8) were considered as the negative control group. At 21 days (before coccidiosis vaccine challenge), the production parameters and cecal short-chain fatty acids were not affected by dietary treatments. The concentrations of total antioxidant capacity in liver samples were elevated in both the MSM and SS groups compared with the control group (p = 0.001). During 21 to 28 days (i.e., one week post coccidiosis vaccine challenge), challenge tended to lower body weight and feed intake by an average of 5.3% (p = 0.262) and 2.8% (p = 0.504), respectively, but to increase the feed conversion ratio by an average of 2.7% (p = 0.087) compared with the non-challenged control groups. None of dietary sulfur groups affected the body weight gain, feed intake, or feed conversion ratio of vaccine-challenged chickens. Mild Eimeria-specific lesions were noted in duodenum (p = 0.006), jejunum (p = 0.017), and ceca (p = 0.047), but dietary sulfur treatments did not affect the Eimeria-induced gut lesion scores. At 28 days, Eimeria challenge significantly impaired (p = 0.001) the apparent ileal digestibility of crude protein and crude ash compared with the naïve control group. Dietary MSM increased the apparent ileal digestibility of crude ash by 15.5% on average compared with the coccidiosis vaccine control group. We conclude that dietary antioxidant sulfur of organic or inorganic origins at the inclusion level (i.e., 0.7 g sulfur/kg of diet) has a limited effect on the growth performance of chickens challenged with coccidiosis vaccine.

Impact of inorganic nitrogenous fertilizers and FYM combinations on plant height at various phases of rice growth and combinations on number of tillers per hill at various stages of effective tillers per hill during rice harvest (Oryza sativa L.)

A pot culture experiment entitled “Impact of inorganic nitrogenous fertilizers and FYM combinations on plant height at various phases of rice growth and combinations on number of tillers per hill at various stages of effective tillers per hill during rice harvest (Oryza sativa L.)” was conducted at Institute of Agricultural Sciences farm, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar Odisha. on sandy loam soil during kharif 2018-2019. The experiment consisted of eight treatments viz. T1-Control, T2- 50% RDF, T3-50% RDF + FYM @ 5 t ha-1, T4-75% RDF, T5-75% RDF + FYM @ 5 t ha-1, T6- 100% RDF ( NPK 80:40:40), T7-100% RDF + FYM @ 5 t ha-1 and T8-150% RDF. The experiment was laid out in a Randomized Block Design with three replications. The results revealed that highest and significant values were recorded with respect to growth parameters i.e., plant height, number of tillers per hill, effective tillers per hill and yield attributes i.e., number of panicles per hill, panicle length, number of filled grains 1000 seed weight (test weight) in the treatment that received 100% RDF + FYM @ 5t ha-1. Combination of FYM (5 t ha-1) with lower levels of RDF (50 and 75% RDF) also registered higher increase in the above parameters as compared to the application of inorganic fertilizers alone with the corresponding levels. Grain and straw yields followed the same trend as that of growth parameters and at higher levels of nitrogen in the inorganic form (150 % RDF) the values of the various parameters including grain and straw yield were significantly lower than the treatment where 100% RDF +FYM @ 5 t ha-1was applied.. More nutrient content (N, P, K) in grain and straw was observed with the application of 100% RDF + FYM @ 5t ha-1 as compared with 100 and 150% RDF. With the combined application of 100 percent RDF as an inorganic source and 5tha-1 FYM as an organic source, improvements in physico-chemical characteristics such as organic carbon, bulk density, porosity, and accessible macro nutrients (N,P,K) were found.

Changes in inorganic phosphorus fractions in weathered soils under long-term intensive cultivation and irrigation

ABSTRACT Conventional intensive cultivation tends to modify the interactions of phosphorus in soil, favoring inorganic forms transformations. The aim of the study was to evaluate the status of inorganic phosphorus and correlate with the chemical, physical and mineralogical soil properties in areas under natural vegetation and different cultivation periods: 1, 17, 22, 28, 32 and 43 years. Soil P was extracted using Chang and Jackson method (Al-P, Fe-P, Ca-P and Residual-P). The micro-chemical map of P concentrations within the representative aggregates was determined by electron probe. Results showed that biofertilizers application in the area under intensive cultivation for 32 years of use significantly increased all soil P fractions (4.249 mg kg−1 in upper soil layer). There was a slight increase in the P at the edges of the aggregates in the first year (0.23%), but at 43 years, there was an increase in contents within the aggregates (0.32%). The intensive cultivation promoted the increase of P content in soil fractions in the arable layer of the soil over time. However, the decline in inorganic P contents after a few years of cultivation suggests that the soils of the studied areas tend to exceed their maximum adsorption capacities in the future.

Pulsos de nitrógeno inorgánico en el suelo y reabsorción foliar de nitrógeno en dos bosques de Pinus hartwegii Lindl.

Introducción: El movimiento de nutrientes en bosques de alta montaña genera información sobre su funcionamiento y respuesta a efectos de cambio climático. La dinámica de nitrógeno en estos ecosistemas se ha estudiado muy poco. Objetivo: Cuantificar los reservorios de N en mantillo, suelo superficial (0-10 cm) y caída de acícula, así como medir las concentraciones temporales de nitrato y amonio en el suelo superficial y la reabsorción de N (ReabsN) en las montañas Jocotilán (JO) y Tláloc (TL) del centro de México. Materiales y métodos. Durante un año se colectaron 108 (JO) y 128 (TL) muestras de suelo y de caída de acícula. Los reservorios de N y ReabsN se compararon entre montañas mediante la prueba Wilcoxon (P &lt; 0.05). Las tendencias temporales de humedad del suelo, formas de N y ReabsN se analizaron con modelos lineales mixtos, considerando el tiempo y la montaña como factores fijos. Resultados y discusión. La humedad gravimétrica, el N total y las concentraciones de nitrato y amonio no difirieron entre montañas. El N inorgánico total (amonio + nitrato) en JO fue mayor que en TL (46 vs. 41 mg∙kg-1). El N en caída de acícula y suelo fueron mayores en JO, pero la ReabsN en TL fue mayor (60 vs. 55 %). La humedad del suelo, el amonio y ReabsN tuvieron un patrón estacional de tendencia cúbica (P &lt; 0.05), denotando pulsos de N. Conclusiones. Los bosques mostraron diferencias en las dinámicas de N en caída de acícula, reabsorción y en formas inorgánicas de N del suelo, indicando que es posible diferenciar su funcionamiento en términos de dicho nutriente.

Effect of various forms and levels of selenium on milk productivity and resistance of lactating cows

The effect of two forms of selenium, inorganic and organic, was evaluated in the study. Lactating cows of the 1st control group were fed 4.9 mg/head/day of inorganic form of selenium, cows of the 2nd, 3rd and 4th experimental groups received organic form of selenium in the amounts of 2.5, 3.7 and 4.9 mg/head/day. Researches show that application of organic form of selenium permits to increase average daily milk yield by 3.3, 12.9 and 10.8% (р &lt; 0.05), while increasing of dry matter concentration in milk by 0.57% (р &lt; 0.05) in comparison with the 1st control group. When administering selenium in organic form 3.7 mg/head/day, there was a tendency to increase in amount of casein and decrease in amount of somatic cells in milk by 0.13% and 33.7 thousand/ cm3 respectively (р &lt; 0.1). A dose of 4.9 mg/head/day of organic selenium contributed to a decrease in amount of somatic cells by 29.3 thousand/cm3 (р &lt; 0.05). Feeding experimental groups with organic form of selenium in different doses had a positive effect on the immune status and antioxidant activity of blood serum. The content of free water-soluble antioxidants (TAWSA) in blood serum was higher by 39.3 and 53.5% (р &lt; 0.001) in cows of the 3rd and 4th experimental groups fed 3.7 and 4.9 mg/head/day of organic selenium. Thus, the use of selenium in organic form is the most effective and allows to reduce the amount of used micronutrient for replenishment of animal needs.

Phosphorus Fractions in Soils of India: A Review

The different nutrient element are exist in different fractions in the soil. The available form of nutrients is responsible for the change in yield of crop significantly. The availability of different pools involves not only their physico-chemical nature but also the ability of the plant to forage them with plant root system. In Indian soil total phosphorus ranges from 100 to 2000 ppm but the available phosphorus ranges from 2 to 20 ppm. The forms of phosphorus present in soil viz. organic and inorganic. The inorganic form of phosphorus constitute about 30-35 per cent of total phosphorus. The inorganic P consist of different pool such as aluminum, iron and calcium bound phosphorus constitutes active form of inorganic P. The reductant-soluble and occluded forms of phosphorus are relatively less active. Different types of phosphorus are interrelated and add to the pool of plant-accessible P as per their physical and chemical properties such as surface area, composition and solubility.

Selenium supplementation in the prevention of coronavirus infections* (*In Memory of Laszlo G. Egyud)

Selenium (Se) is a ubiquitous element akin to sulfur (S) existing in the Earth’s crust in various organic and inorganic forms. Selenium concentration varies greatly depending on the geographic area. Consequently, the content of selenium in food products is also variable. It is known that low Se is associated with an increased incidence of cancer and heart diseases. Therefore, it is advisable to supplement your diet with this element albeit in a proper form. Although blood increased concentrations of Se can be achieved with various pharmacological preparations only one chemical form (sodium selenite) can offer true protection. Sodium selenite, but not selenate, can oxidize thiol groups in the virus protein disulfide isomerase rendering it unable to penetrate the healthy cell membrane. In this way, selenite inhibits the entrance of viruses into the healthy cells and abolishes their infectivity. Therefore, this simple chemical compound can potentially be used in the recent battle against the coronavirus epidemic.

Soil phosphorus fractions and their relation to leaf litterfall in a central Amazonian terra firme rainforest

ABSTRACT Phosphorus (P) cycling is an important yet poorly studied aspect of the macronutrient balance in tropical rainforest ecosystems. As soil P occurs in different organic and inorganic forms (fractions) with varying degrees of lability, we hypothesized that these fractions will vary between soil types, and temporally within soil types. Additionally, we hypothesized a direct influence of leaf litterfall P input on soil total P and soil P fractions. We collected soil and leaf litter samples from three soil types in a central Amazonian lowland rainforest in Brazil over five months, and used a modified Hedleys fractionation method to determine six organic and inorganic soil P fractions, and also total, labile and residual P. Leaf litterfall P concentrations were determined colorimetrically. Soil inorganic and organic P fractions varied between soil types and across months, but soil type and month interactions were mostly non-significant. Some inorganic P fractions (Pi-NaOH) peaked while the organic fractions (Po-NaOH) fell and vice versa. Leaf litterfall production and leaf litterfall P input peaked around two months following the wettest month. Leaf litterfall P input was a significant predictor of Po-NaHCO3, a bioavailable P fraction. Future studies on P cycling in terrestrial ecosystems should examine the roles played by individual soil P fractions as they cycle asynchronistically and differently across soil types.

Transcriptomic Dissection of Allotetraploid Rapeseed (Brassica napus L.) in Responses to Nitrate and Ammonium Regimes and Functional Analysis of BnaA2.Gln1;4 in Arabidopsis.

Plant roots acquire nitrogen predominantly as two inorganic forms, nitrate (NO3-) and ammonium (NH4+), to which plants respond differentially. Rapeseed (Brassica napus L.) is an important oil-crop species with very low nitrogen-use efficiency (NUE), the regulatory mechanism of which was elusive due to the vastness and complexity of the rapeseed genome. In this study, a comparative transcriptomic analysis was performed to investigate the differential signatures of nitrogen-starved rapeseed in responses to NO3- and NH4+ treatments and to identify the key genes regulating rapeseed NUE. The two nitrogen sources differentially affected the shoot and root transcriptome profiles, including those of genome-wide nitrogen transporter and transcription factor (TF)-related genes. Differential expression profiling showed that BnaA6.NRT2;1 and BnaA7.AMT1;3 might be the core transporters responsible for efficient NO3- and NH4+ uptake, respectively; the TF genes responsive to inorganic nitrogen, specifically responding to NO3-, and specifically responsive to NH4+ were also identified. The genes which were commonly and most significantly affected by both NO3- and NH4+ treatments were related to glutamine metabolism. Among the glutamine synthetase (GS) family genes, we found BnaA2.Gln1;4, significantly responsive to low-nitrogen conditions and showed higher transcription abundance and GS activity in the leaf veins, flower sepals, root cortex and stele, silique petiole and stem tissues. These characters were significantly different from those of AtGln1;4. The heterologous overexpression of BnaA2.Gln1;4 in Arabidopsis increased plant biomass, NUE, GS activity and total amino acid concentrations under both sufficient- and low-nitrogen conditions. Overall, this study provided novel information about the genes involved in the adaptation to different nitrogen regimes and identified some promising candidate genes for enhancing NUE in rapeseed.

Preferences for different nitrogen forms in three dominant plants in a semi-arid grassland under different grazing intensities

Plant species generally absorb different nitrogen (N) forms from soil in ways that minimize N niche overlap, but whether and how grazing affects a plant’s preferred form of N remains unclear. Using the in-situ stable N isotope-labeling technique, we explored the preference of plants in taking up N of different chemical forms along an experimental gradient of grazing intensity in a semi-arid grassland in Inner Mongolia. 15N-labelled nitrate (NO3−), ammonium (NH4+) and glycine solutions were injected into the soil under nil (G0, as a control), light (G1) and heavy grazing (G2) grassland plots in June and August. Uptake of these three N forms was determined for three dominant plants, Leymus chinensis, Stipa grandis and Cleistogenes squarrosa. L. chinensis had the highest N acquisition capacity. Regardless of species, N absorption was higher in August than in June. While all three plant species absorbed glycine-N, they preferentially absorbed N in its inorganic forms (NO3−-N + NH4+-N), with NO3−-N having the highest uptake. Irrespective of grazing intensity, during peak growth (August) all three plant species preferred to absorb NO3−-N (the dominant N form) than NH4+-N or glycine-N. In contrast, in June plants differed in their preferred form of N uptake depending on the grazing treatment. Under heavy grazing (G2), all plants preferentially absorbed NO3−-N. Under light grazing (G1), all plants absorbing all three N chemical forms with no significant difference. Under no grazing (G0), L. chinensis preferentially absorbed NO3−-N but otherwise there was no significant effect of grazing intensity on the preferred form of N. Our results indicate that the three species of plants that we observed altered their N-uptake preference in response to grazing intensity differently in the early growth and vigorous growth stages. Plant N niche differentiation in time, space and chemical N forms needs to be explored systematically in future studies to aid understand of grazing effects on N processes in grassland ecosystem.