Zinc Uptake Research Articles

Precise partial root-zone irrigation technique and potassium-zinc fertigation management improve maize physio-biochemical responses, yield, and water use in arid climate

BackgroundTo optimize irrigation water use and productivity, understanding the interactions between plants, irrigation techniques, and fertilization practices is crucial. Therefore, the experiment aims to assess the effectiveness of two application methods of potassium humate combined with chelated zinc under partial root-zone drip irrigation techniques on maize nutrient uptake, yield, and irrigation water use efficiency across two irrigation levels.MethodsOpen-field experiments were carried out in two summer seasons of 2021 and 2022 under alternate and fixed partial root-zone drip irrigation techniques to investigate their impacts at two irrigation levels and applied foliar and soil applications of potassium humate or chelated zinc in a sole and combinations on maize.ResultsDeficit irrigation significantly increased hydrogen peroxide levels and decreased proline, antioxidant enzymes, carbohydrate, chlorophyll (a + b), and nutrient uptake in both partial root-zone techniques. The implementation of combined soil application of potassium humate and chelated zinc under drought conditions on maize led to varying impacts on antioxidant enzymes and nutritional status, depending on the type of partial root-zone technique. Meanwhile, the results showed that fixed partial root-zone irrigation diminished the negative effects of drought stress by enhancing phosphorus uptake (53.8%), potassium uptake (59.2%), proline (74.4%) and catalase (75%); compared to the control. These enhancements may contribute to improving the defense system of maize plants in such conditions. On the other hand, the same previous treatments under alternate partial root zone modified the defense mechanism of plants and improved the contents of peroxidase, superoxide dismutase, and the uptake of magnesium, zinc, and iron by 81.3%, 82.3%, 85.1%, 56.9%, and 80.2%, respectively.ConclusionsAdopting 75% of the irrigation requirements and treating maize plants with the soil application of 3 g l−1 potassium humate combined with 1.25 kg ha−1 chelated zinc under alternate partial root-zone technique, resulted in the maximum root length, leaf water content, chlorophyll content, yield, and irrigation water use efficiency.

Effect of Zinc Application on Growth, Yield, Zinc uptake and Zinc Use Indices of Rice

A field experiment was conducted at the agriculture farm, Palli Siksha Bhavana, Visva-Bharati, Birbhum, West Bengal, India during kharif (rainy) seasons (June–September) of 2016 and 2017 to study effect of zinc application on growth, yield and nutrient uptake of rice. The experiment was laid out in split plot design replicated thrice, consisting two main plot treatments i.e. crop establishment methods (CEMs) and seven sub-plot treatments (levels of zinc and methods of application). Two CEMs were direct seeded rice (DSR) and transplanted puddled rice (TPR) and seven levels of zinc and methods of application were namely control (Zn0), Seed coating of Zn @ 1250 mg kg-1 (Zn1), Seed coating of Zn @ 2500 mg kg-1 (Zn2), Seed coating of Zn @ 3750 mg kg-1 (Zn3), two foliar sprays @ 1050 mg kg-1 (Zn4), three foliar spray @ 1050 mg kg-1 (Zn5), 2500 mg kg-1 seed coating+2-foliar spray @ 1050 mg kg-1 (Zn6). In respect of yield attribute and yield, Zn6 resulted significantly highest number of Panicle m-2 as well as number of filled grains panicle-1. Zn3 though recorded 5.7% more grain yield than Zn6 but later Zn6 resulted highest zinc concentration and uptake. Zn1 recorded highest zinc use indices. Zn1 resulted much highest Zn use efficiency than foliar application and combined application of seed coating and foliar spray. Correlation between Zn levels and Zn concentration in both grain and straw of rice was highly positive; very highly positive correlation was recorded with the Zn levels and Zn uptake by both grain and straw.

Effect of Different Zinc Sources and Application Methods on Content and Uptake of Micronutrients of Basmati Rice

Zinc (Zn) is an essential trace element for plants, animals and human’s health. Zn deficiency is widely spread in paddy soils of India and has negative impact on national rice production. Field experiment on rice crop was conducted in sandy loam soil at crop research center Chirodi of SVBP University of Agriculture and Technology, Meerut., during Kharif season of 2011 and 2012 toevaluate the “Effect of different sources and application methods of zinc on content and uptake of micronutrients in basmati rice crop in sandy loam soil. The experiment was laid out in randomized block design with three replications. The experiment comprised of twelve treatments viz.; T1 (control), T2 (recommended NPK @120:60:60 kg ha-1) T3 (5 kg Zn through ZnSO4.7H2O+RDF), T4(5 kg Zn through mono ZnSO4.7H2O),T5 (0.1% Zn spray through ZnSO4.7H2O+RDF ),T6 (0.1% Zn spray through ZnSO4.7H2O + RDF),T7 (0.012% Zn spray through chelated Zn at tillering + RDF),T8 (0.05% Zn spray through ZnSO4.7H2O at tillering +0.05% at panicle initiation+ RDF), T9 (0.05% Zn spray through mono ZnSO4.7H2O at tillering + 0.05% at panicle initiation +RDF),T10 (0.006% Zn spray through chelated Zn at tillering + 0.006% at panicle initiation+ RDF ), T11 (micronutrient mixture@ 25kg ha-1 + RDF), T12 (vermicompost @ 3tha-1+ RDF).The experimental soil was low in organic carbon and available nitrogen and medium in phosphorus and higher in potassium with slightly alkaline in pH. The status of DTPA extractable Zn 1.23 mg Kg-1,Fe 14.85 mg Kg-1 Cu 2.43 mg Kg-1 Mn 10.91 mg Kg-1 in the surface soil. Nutrient assimilation at different stages by the rice crop varied significantly due to application of different treatments in the study. Maximum zinc content 85.78 and 93.57 ppm and uptake 288.60 and 341.85 g/ha at 30 DAT during 2011 and 2012 found in T12 which was significantly higher than the rest of the treatments while minimum zinc content recorded in T1 was significantly lower than the rest of the treatments during both the years. Similar trends were also recorded at 60 DAT, grain and straw growth stages of rice plant. The zinc content of plant sample in T11 and T3 was also higher and statistically at par to the level of zinc content recorded in T12. The Cu, Fe, and Mn content and uptake at different growth stages of rice plant sample in T11 and T3 was also higher and like the level in T12. Among the method of Zn application, soil application resulted in higher biomass, micronutrient content and uptake in the grain and straw. Foliar application caused greater effect on zinc content and uptake and as well as content and uptake of Cu, Fe and Mn in rice plant at different growth stages during both the years. Among the sources of Zinc, ZnSO4.7H2O proved to be the most efficient source of Zn for rice production.

TSQ Incubation Enhances Autometallographic Zinc Detection in Cultured Astrocytes.

Zinc is a critical ion for a large number of cellular functions. In the central nervous system, zinc ions are involved in synaptic transmission. Therefore, zinc homeostasis is essential, and cells have developed a variety of mechanisms to control cellular zinc concentration, including the zincosome formation. Alterations of free zinc levels have been associated with brain dysfunction and are present in many illnesses and syndromes. Astrocytes are implicated in the maintenance of the neuronal milleu and brain homeostasis. In this work, we have analyzed the combination of direct (TSQ) and indirect (autometallography) zinc detection methods to increase sensitivity for studying zinc uptake by rat astrocytes in vitro. Zincosome formation was visualized with the zinc fluorochrome TSQ by light microscopy. Additionally, we improved both zinc precipitation and cellular fixation methods to preserve zinc ions and make them suitable for autometallography development. Our tests pinpointed paraformaldehyde and sodium sulfide as the more adequate methods for cellular fixation and zinc precipitation, respectively. TSQ incubation and pH of the fixative were shown to be crucial for autometallography. Using this improved method, we visualized the zinc content of zincosomes at the ultrastructural level both as silver autometallographic precipitates and as electrodense sulfide-osmium zinc precipitates.

Uptake of zinc from the soil to the wheat grain: Nonlinear process prediction based on artificial neural network and geochemical data

Trace elements in plants primarily derive from soils, subsequently influencing human health through the food chain. Therefore, it is essential to understand the relationship of trace elements between plants and soils. Since trace elements from soils absorbed by plants is a nonlinear process, traditional multiple linear regression (MLR) models failed to provide accurate predictions. Zinc (Zn) was chosen as the objective element in this case. Using soil geochemical data, artificial neural networks (ANN) were utilized to develop predictive models that accurately estimated Zn content within wheat grains. A total of 4036 topsoil samples and 73 paired rhizosphere soil-wheat samples were collected for the simulation study. Through Pearson correlation analysis, the total content of elements (TCEs) of Fe, Mn, Zn, and P, as well as the available content of elements (ACEs) of B, Mo, N, and Fe, were significantly correlated with the Zn bioaccumulation factor (BAF). Upon comparison, ANN models outperformed MLR models in terms of prediction accuracy. Notably, the predictive performance using ACEs as input factors was better than that using TCEs. To improve the accuracy, a two-step model was established through multiple testing. Firstly, ACEs in the soil were predicted using TCEs and properties of the rhizosphere soil as input factors. Secondly, the Zn BAF in grains was predicted using ACE as input factors. Consequently, the content of Zn in wheat grains corresponding to 4036 topsoil samples was predicted. Results showed that 85.69 % of the land was suitable for cultivating Zn-rich wheat. This finding offers a more accurate method to predict the uptake of trace elements from soils to grains, which helps to warn about abnormal levels in grains and prevent potential health risks.

Maize zinc uptake is influenced by arbuscular mycorrhizal symbiosis under various soil phosphorus availabilities.

The antagonistic interplay between phosphorus (P) and zinc (Zn) in plants is well established. However, the molecular mechanisms mediating those interactions as influenced by arbuscular mycorrhizal (AM) symbiosis remain unclear. We investigated Zn concentrations, root AM symbiosis, and transcriptome profiles of maize roots grown under field conditions upon different P levels. We also validated genotype-dependent P-Zn uptake in selected genotypes from a MAGIC population and conducted mycorrhizal inoculation experiments using mycorrhizal-defective mutant pht1;6 to elucidate the significance of AM symbiosis in P-Zn antagonism. Finally, we assessed how P supply affects Zn transporters and Zn uptake in extraradical hyphae within a three-compartment system. Elevated P levels led to a significant reduction in maize Zn concentration across the population, correlating with a marked decline in AM symbiosis, thus elucidating the P-Zn antagonism. We also identified ZmPht1;6 is crucial for AM symbiosis and confirmed that P-Zn antagonistic uptake is dependent on AM symbiosis. Moreover, we found that high P suppressed the expression of the fungal RiZRT1 and RiZnT1 genes, potentially impacting hyphal Zn uptake. We conclude that high P exerts systemic regulation over root and AM hyphae-mediated Zn uptake in maize. These findings hold implications for breeding Zn deficiency-tolerant maize varieties.

Characterization of the dual regulation by a c-di-GMP riboswitch Bc1 with a long expression platform from Bacillus thuringiensis.

A riboswitch generally regulates the expression of its downstream genes through conformational change in its expression platform (EP) upon ligand binding. The cyclic diguanosine monophosphate (c-di-GMP) class I riboswitch Bc1 is widespread and conserved among Bacillus cereus group species. In this study, we revealed that Bc1 has a long EP with two typical ρ-independent terminator sequences 28 bp apart. The upstream terminator T1 is dominant in vitro, while downstream terminator T2 is more efficient in vivo. Through mutation analysis, we elucidated that Bc1 exerts a rare and incoherent "transcription-translation" dual regulation with T2 playing a crucial role. However, we found that Bc1 did not respond to c-di-GMP under in vitro transcription conditions, and the expressions of downstream genes did not change with fluctuation in intracellular c-di-GMP concentration. To explore this puzzle, we conducted SHAPE-MaP and confirmed the interaction of Bc1 with c-di-GMP. This shows that as c-di-GMP concentration increases, T1 unfolds but T2 remains almost intact and functional. The presence of T2 masks the effect of T1 unwinding, resulting in no response of Bc1 to c-di-GMP. The high Shannon entropy values of EP region imply the potential alternative structures of Bc1. We also found that zinc uptake regulator can specifically bind to the dual terminator coding sequence and slightly trigger the response of Bc1 to c-di-GMP. This work will shed light on the dual-regulation riboswitch and enrich our understanding of the RNA world.IMPORTANCEIn nature, riboswitches are involved in a variety of metabolic regulation, most of which preferentially regulate transcription termination or translation initiation of downstream genes in specific ways. Alternatively, the same or different riboswitches can exist in tandem to enhance regulatory effects or respond to multiple ligands. However, many putative conserved riboswitches have not yet been experimentally validated. Here, we found that the c-di-GMP riboswitch Bc1 with a long EP could form a dual terminator and exhibit non-canonical and incoherent "transcription-translation" dual regulation. Besides, zinc uptake regulator specifically bound to the coding sequence of the Bc1 EP and slightly mediated the action of Bc1. The application of SHAPE-MaP to the dual regulation mechanism of Bc1 may establish the foundation for future studies of such complex untranslated regions in other bacterial genomes.

Adaptations in Gastrointestinal Nutrient Absorption and its Determinants During Pregnancy in Monogastric Mammals: A Scoping Review.

Pregnancy increases nutrient demand, but how nutrient uptake and its determinants adapt to facilitate this is unclear. This review aimed to identify and characterize evidence and evidence gaps regarding changes in gastrointestinal nutrient absorption and its determinants during pregnancy in monogastric mammals. A scoping review of peer-reviewed sources was conducted across PubMed, Scopus, Web of Science, Embase, and ProQuest (theses and dissertations) databases. Data extracted included species, pregnancy stages and outcomes. Where sufficient data for a given outcome was available, relative values were summarized graphically or in tables, to allow comparison across pregnancy stages and/or small intestine regions. Searches identified 26 855 sources, of which only 159 were eligible. Mechanistic studies were largely restricted to rodents, and most compared non- and late-pregnant groups, with fewer studies including early- or mid-pregnant groups. During pregnancy, there is some evidence for greater capacity for glucose uptake but unchanged amino acid uptake, and good evidence for increased uptake of calcium, iron, and zinc, and slower gastrointestinal passage of nutrients. The available evidence indicates that acute glucose uptake, gastric emptying, and the activities of sucrase, maltase, and lactase do not change during pregnancy. Gaps in the knowledge include the effects of pregnancy on uptake of specific amino acids, lipids, and most minerals and vitamins. The results indicate that the gastrointestinal tract adapts during pregnancy to facilitate increased nutrient absorption. Additional data is required in order to assess the underlying mechanisms for and impacts on the absorption of many nutrients, as well as to determine the timing of these adaptations.

Physiological responses of the nickel hyperaccumulator Bornmuellera emarginata under varying nickel dose levels and pH in hydroponics

Abstract Background and aims The nickel hyperaccumulator Bornmuellera emarginata (Brassicaceae) is a species adapted to thrive on naturally nickel-enriched ultramafic soils in the Balkans and a promising candidate for use in nickel agromining. The main aim of this study was to provide insight into the physiological mechanisms of nickel hyperaccumulation in B. emarginata. Methods Bornmuellera emarginata was cultivated under various nickel exposure concentrations (control, 1, 10, and 100 µM nickel in solution), and different pH levels of the hydroponic solution for four weeks. During this period, the plants underwent assessment for various physiological parameters, including photosynthetic pigments, leaf relative water content, tolerance index, and metal accumulation in plant tissues. Results The results show that the translocation factors and bioconcentration factors were > 1 even at 1 µM nickel in solution. This confirms the ability of B. emarginata to hyperaccumulate nickel (up to 6600 mg kg−1) over a wide range of nickel concentrations in hydroponics. Nickel at 100 µM (a concentration that is an order of magnitude higher than the highest soil solution nickel concentration found in ultramafic soils) induced only mild physiological stress symptoms (e.g. a minor proline response). Alterations in the solution pH did not cause any significant effect on nickel accumulation in the plants. Conclusions Bornmuellera emarginata is a highly adapted nickel-tolerant and nickel hyperaccumulating species that shows very little stress responses even to extreme nickel exposure concentrations in hydroponics. This species shows interesting trade-off responses between nickel and other metals, including non-competitive uptake of zinc. The potential for this species to accumulate zinc should therefore be further explored.

Flowering, Quality and Nutritional Status of Tropaeolum majus L. ‘Spitfire’ after Application of Trichoderma spp.

The aim of this study was to compare the influence of three species of fungi of the Trichoderma genus (T. aureoviride Rifai—Ta8, T. hamatum/Bonord/Bainier—Th15, and T. harzianum Rifai—Thr2) on the quality, flowering, and nutritional status of Tropaeolum majus L. ‘Spitfire’. Early flowering was only influenced by T. hamatum, which delayed it by 6 days. T. aureoviride, T. hamatum, and T. harzianum stimulated the flowering of the ‘Spitfire’ cultivar but did not affect the size of the flowers. The plants treated with T. harzianum after being planted in pots flowered the most abundantly. Trichoderma spp. caused the plants to grow more intensively, producing longer and more leafy shoots with a greater number of offshoots. Trichoderma spp. stimulated the uptake of macronutrients, except for phosphorus (P). In the case of calcium (Ca) and sodium (Na), this phenomenon was only observed in plants treated with T. aureoviride and T. hamatum, and for magnesium (Mg), only when T. hamatum was applied to sown seeds. As for the developed root systems, as far as the micronutrients are concerned, Trichoderma spp. stimulated the uptake of zinc (Zn) and manganese (Mn). Apart from that, there was a higher iron (Fe) content in the plants treated with T. harzianum on both dates and T. aureoviride after planting the plants in pots.

Identification and characterization of zinc importers in Corynebacterium diphtheriae.

Corynebacterium diphtheriae is the causative agent of diphtheria, a severe respiratory disease in humans. C. diphtheriae colonizes the human upper respiratory tract, where it acquires zinc, an essential metal required for survival in the host. While the mechanisms for zinc transport by C. diphtheriae are not well characterized, four putative zinc ABC-type transporter loci were recently identified in strain 1737: iutABCD/E (iut), znuACB (znu), nikABCD1 (nik1), and nikABCD2 (nik2). A mutant deleted for all four loci (Δ4) exhibited similar growth to that of the wild-type strain in a zinc-limited medium, suggesting there are additional zinc transporters. Two additional gene loci predicted to be associated with metal import, mntABCD (mnt) and sidAB (sid), were deleted in the Δ4 mutant to construct a new mutant designated Δ6. The C. diphtheriae Δ6 mutant exhibited significantly reduced growth under zinc limitation relative to the wild type, suggesting a deficiency in zinc acquisition. Strains retaining the iut, znu, mnt, or sid loci grew to near-wild-type levels in the absence of the other five loci, indicating that each of these transporters may be involved in zinc uptake. Plasmid complementation with cloned iut, znu, mnt, or nik1 loci also enhanced the growth of the Δ6 mutant. Quantification of intracellular zinc content by inductively coupled plasma mass spectrometry was consistent with reduced zinc uptake by Δ6 relative to the wild type and further supports a zinc uptake function for the transporters encoded by iut, znu, and mnt. This study demonstrates that C. diphtheriae zinc transport is complex and involves multiple zinc uptake systems.IMPORTANCEZinc is a critical nutrient for all forms of life, including human bacterial pathogens. Thus, the tools that bacteria use to acquire zinc from host sources are crucial for pathogenesis. While potential candidates for zinc importers have been identified in Corynebacterium diphtheriae from gene expression studies, to date, no study has clearly demonstrated this function for any of the putative transporters. We show that C. diphtheriae encodes at least six loci associated with zinc import, underscoring the extent of redundancy for zinc acquisition. Furthermore, we provide evidence that a previously studied manganese-regulated importer can also function in zinc import. This study builds upon our knowledge of bacterial zinc transport mechanisms and identifies potential targets for future diphtheria vaccine candidates.

The c.503A>G polymorphism in ZIP1-II of Pacific oyster Crassostrea gigas associated with zinc content

The Pacific oyster Crassostrea gigas is renowned for its high zinc content, but the significant variation among individuals diminishes its value as a reliable source of zinc supplementation. The Zrt/Irt-like protein 1 (ZIP1), a pivotal zinc transporter that facilitates zinc uptake in various organisms, plays crucial roles in regulating zinc content. In the present study, polymorphisms of a ZIP1 gene in C. gigas (CgZIP1-II) were investigated, and their association with zinc content was evaluated through preliminary association analysis in 41 oysters and verification analysis in another 200 oysters. A total of 17 single nucleotide polymorphisms (SNPs) were identified in the exonic region of CgZIP1-II gene, with c.503A>G significantly associated with zinc content. Protein sequence and structure prediction showed that c.503A>G caused a p.Met110Val nonsynonymous mutation located in the metal-binding region of CgZIP1-II, which could influence its affinity for zinc ions, thereby modulating its zinc transport functionality. These results indicate the potential influence of CgZIP1-II polymorphisms on zinc content and provide candidate markers for selecting C. gigas with high zinc content.

The genes mgtE and spoVG are involved in zinc tolerance of Staphylococcus aureus.

Staphylococcus aureus is an opportunistic pathogen causing tremendous public health burden and high mortality in invasive infections. Treatment is becoming increasingly difficult due to antimicrobial resistances. The use of metals in animal husbandry and aquaculture to reduce bacterial growth and subsequent acquisition of metal resistances has been shown to co-select for antimicrobial resistance. Therefore, understanding adaptive mechanisms that help S. aureus to survive metal exposure is essential. Using a screening approach, we were able to identify two genes encoding the transporter MgtE and the transcriptional regulator SpoVG, which conferred increased tolerance to specific metals such as zinc when inactivated. Further testing showed that the deletion of mgtE leads to reduced intracellular zinc levels, suggesting a role in zinc uptake. The accumulation of mutations in these genes when exposed to other metals suggests that inactivation of these genes could be a common mechanism for intrinsic tolerance to certain metals.

Analysis of similarities and differences between transient symptomatic zinc deficiency and acrodermatitis enteropathica in children: a case report of a Chinese Yi-ethnic infant

BackgroundTransient symptomatic zinc deficiency (TSZD), an acquired type of zinc deficiency, is a rare, but probably underrecognized disease, extremely in breastfed premature with low birthweight infants. Its clinical manefestations are similar to Acrodermatitis enteropathica (AE), which is a genetic zinc absorption disorder caused by SLC39A4 gene mutations. This gene encodes a member of the zinc/iron-regulated transporter-like protein (ZIP) family. The encoded protein localizes to cell membranes and is required for zinc uptake in the intestine. TSZD is often misdiagnosed as AE because of their extremely similar manefestations, characterized by a typical rash. Therefore, the differention between them is still a clinical challenging.Case presentationHere, we present a case of TSZD in a 4 month and 23 days female Chinese Yi-ethnic premature with AE-like skin lesions, mainly presenting periorificial, perianal and perineal crusted, eroded, erythemato-squamous eruption. Laboratory examination showed the patient’s blood zinc level was significantly decreased. Further sequencing of the SLC39A4 gene showed no mutation in the infant and her parents. Skin lesions significantly improved after 6 days of initial zinc supplementation (3 mg/kg/d), and maintenance treatment with 1 mg/kg/day of zinc was discontinued after 8 months without recurrence.ConclusionsThe clinical manifestations of TSZD and AE are extremely similar, leading to a high rate of clinical misdiagnosis. While genetic analysis of the SLC39A4 gene is a reliable method for differentiating TSZD from AE. It is recommended that SLC39A4 gene test should be performed as far as possible in children with AE-like rash.

Zinc uptake in rice (Oryza sativa)-wheat (Triticum aestivum) cropping system under the influence of microbial consortia (Pusa decomposer) mediatedin situ rice straw management options

A field experiment was conducted during the rainy (kharif) and winter (rabi) seasons of 2019–20 and 2020–21 at research farm of ICAR-Indian Agricultural Research Institute, New Delhi to study the effect of various crop establishment methods and microbial consortia (Pusa decomposer) mediated in situ rice straw management options on zinc (Zn) concentration and uptake in rice (Oryza sativa L.) (cv. Pusa Basmati 1509) and wheat (Triticum aestivum L.) (cv. HD 2967). The experiment was laid out in split-plot design (SPD) with 3 replications having 2 main plot (main factor) treatments, viz. aerobic rice (AR); and conventional transplanted (CT) rice in wet season; and 7 sub- plot (sub-factor) treatments, viz. Clean cultivation (removal of paddy straw); Paddy straw incorporation (PSI); Paddy straw mulching (PSM); PSI + Pusa decomposer (PD); PSM + PD; PSI + urea @20 kg/ha; and PSI + PD + urea @10 kg/ha in dry season. Findings showed that, in rice the zinc concentration (18.51 and 20.30 mg/kg in grain; 57.02 and 57.81 mg/kg in straw) and uptake (78.38 and 89.81 g/ha in grain; 427.1 and 434.6 g/ha in straw) were significantly superior in CT rice than AR in main plots during both the years of experiments. However, sub-plot treatments were non-significant in the zinc concentration and uptake. In wheat, among in situ rice straw management options (sub- plots), paddy straw incorporation + Pusa decomposer + Urea @10 kg/ha treatment significantly resulted in higher Zn concentration (38.08 and 39.03 mg/kg in grain; 28.24 and 29.01 mg/kg in straw) and uptake (185.0 and 191.9 g/ha in grain; 234.2 and 242.6 g/ha in straw) compared to other treatments and control (clean cultivation). The principal component analysis revealed that Zn uptake positively correlated with straw and grain yields in rice and wheat. Thus, the same treatment was found to be a better option for higher Zn concentration and uptake in the rice-wheat cropping system.

Targeted removal of the FA2 site on human albumin prevents fatty acid–mediated inhibition of Zn2+ binding

Zinc is required for virtually all biological processes. In plasma, Zn2+ is predominantly transported by human serum albumin (HSA), which possesses two Zn2+-binding sites of differing affinities (sites A and B). Fatty acids (FAs) are also transported by HSA, with seven structurally characterized FA-binding sites (named FA1-FA7) known. FA binding inhibits Zn2+-HSA interactions, in a manner that can impact upon hemostasis and cellular zinc uptake, but the degree to which binding at specific FA sites contributes to this inhibition is unclear. Wild-type HSA and H9A, H67A, H247A, and Y150F/R257A/S287A (FA2-KO) mutant albumins were expressed in Pichia pastoris. Isothermal titration calorimetry studies revealed that the Zn2+-binding capacity at the high-affinity Zn2+ site (site A) was reduced in H67A and H247A mutants, with site B less affected. The H9A mutation decreased Zn2+ binding at the lower-affinity site, establishing His9 as a site B ligand. Zn2+ binding to HSA and H9A was compromised by palmitate, consistent with FA binding affecting site A. 13C-NMR experiments confirmed that the FA2-KO mutations prohibited FA binding at site FA2. Zn2+ binding to the FA2-KO mutant was unaffected by myristate, suggesting binding at FA2 is solely responsible for inhibition. Molecular dynamics studies identified the steric obstruction exerted by bound FA in site FA2, which impedes the conformational change from open (FA-loaded) to closed (FA-free) states, required for Zn2+ to bind at site A. The successful targeting of the FA2 site will aid functional studies exploring the interplay between circulating FA levels and plasma Zn2+ speciation in health and disease.

A flow equilibrium of zinc in cells of Cupriavidus metallidurans.

Understanding the biochemical action of a single enzyme or transport protein is the pre-requisite to obtain insight into its cellular function but this is only one half of the coin. The other side concerns the question of how central metabolic functions of a cell emerge from the interplay of different proteins and other macromolecules. This paper demonstrates that a flow equilibrium of zinc uptake and efflux reactions is at the core of cellular zinc homeostasis and identifies the most important contributors to this flow equilibrium: the uptake and efflux systems and metal-binding components of the cytoplasm.

Comparative analysis of nutrient absorption in rice cultivation: Aerobic versus anaerobic conditions in furrow‐irrigated rice

AbstractRice (Oryza sativa L.) production in the Mid‐Southern United States has traditionally been under conventional flood (CF) production, namely, direct‐seeded and delayed‐flood production. However, furrow‐irrigated rice (FIR) has grown to comprise over 15% of Arkansas’ and 30% of Missouri's rice hectarage. The uptake of several nutrients, including phosphorus (P), potassium (K), and zinc (Zn), has been shown to differ between aerobic and flooded rice production. Hence, a nutrient uptake survey was conducted from 2018 to 2020 in FIR fields to determine the difference in nutrient uptake (macro‐ and micronutrients) between the upper generally aerobic environment at the top of the field and the bottom of the field, where a generally anaerobic or flooded environment existed from R1 to maturity. Aboveground biomass samples were taken at R3 from four nitrogen (N) treatments at the top and bottom of five sites on a clayey soil texture and four sites on a loamy soil texture. Results suggest that there is significantly lower P, K, sodium (Na), and manganese (Mn) uptake at the top of the field compared to the bottom of the field on both soil textures. Additionally, the N treatments that yielded the highest biomass generally led to the greatest uptake of all nutrients examined. The decrease in P and K uptake in the aerobic portion of an FIR field suggests that they may require altered fertilizer recommendations compared to the traditional CF rice system.

Biological Removal of Zinc (II) by Fusarium solani under Different Modes of Operational Strategies: A Comparative Study

The goal of the current batch biosorption experiment was to determine how well Fusarium solani (isolated from soil) resting cells could remove zinc (II) from aqueous solution. With an increase in pH (up to pH 5.0) and an increase in initial zinc (II) concentration of up to 500 mg/L, the specific zinc (II) removal increases. By increasing biomass content from 2.5 to 5.5 g/L, the specific zinc (II) removal remained nearly constant. The investigations also utilised resting cells from various growth stages and at an initial zinc (II) concentration of 500 mg/L, the maximum specific zinc (II) uptake (51.7 mg/g) was accomplished (36 h old). The comparison of the results revealed that cells in a growing state (63.9 mg/g) can achieve the highest selective uptake. Hence, the uptake of zinc(II) under various operational strategies was only done with growing cells. The biological uptake of zinc (II) was then done in a fed batch mode of operation using Fusarium solani growing cells. Increased volume pulse feeding (IVPF) and constant volume pulse feeding (CVPF) were used to study the fed batch process and the impacts of these operational methods on biological performance were contrasted with those of a traditional batch process. According to batch experiments, at pH 5.0 and an initial zinc (II) ion concentration of 500 mg/l, the maximum specific zinc (II) removal was 63.9 mg/g. The maximal specific zinc (II) removal in the IVPF process was determined to be 45.47 mg/g and 33.58 mg/g, but the values in the CVPF process were 33.12 mg/g and 22.59 mg/g respectively for the first and second pulse feedings in both cases. The zinc (II) uptake found in prior investigations carried out by the current authors employing the continuous mode of operation was then compared with these results. The process could be run for a longer period of time with a maximum specific zinc (II) removal of 52.8 mg/g when operating in a continuous mode which was shown to be the optimal operational strategy.

Zinc Application Enhances Tuber Quality and Zinc Bioavailability in Potato (Solanum tuberosum L.) in the Tarai Region of Uttarakhand

As evident from plant and soil investigations, 49 per cent of Indian soils are deficient in zinc. This could affect the production and quality of potato (Solanum tuberosum L.) as the crop is moderately sensitive to zinc deficiency. Zinc is considered to be the most important micronutrient for potato and its reduced availability in the plant is the major constraint to obtaining good tuber quality. However, repeated practice of rice-wheat cropping system in the tarai region of Uttarakhand has led to zinc deficiency in the soil, and thereby, its availability in the tubers. Therefore, the present investigation was undertaken at the Vegetable Research Centre of Govind Ballabh Pant University of Agriculture and Technology, Pantnagar (Uttarakhand) during the rabi season of 2021-22 with the objective to enhance the quality of potato tubers, and at the same time, increase the bioavailability of zinc in the tubers. The experiment was laid out in a randomised complete block design with twelve treatments and four replications. The results of the experiment revealed that foliar application of ZnSO4 @ 2 g L-1 at 25 and 50 days after planting recorded the highest dry matter content (20.73%), specific gravity (1.07 g cm-3) and starch content (17.10%) in the tubers. The zinc content in tubers (47.58 ppm) and zinc uptake by tubers (2.85 kg ha-1) were also found to be maximum in the same treatment combination. Hence, the same treatment combination can be recommended for getting better quality of potato tubers as well as increasing zinc bioavailability in potato under the tarai region of Uttarakhand.