Zn Concentrations Research Articles

Determination of Metal Cadmium (Cd), Copper (Cu), Iron (Fe) and Zinc (Zn) in Drinking Water from The Boring Well of Surbakti Village, Karo District by Atomic Absorption Spectrophotometry Method

Water is an essential requirement for human existence. In addition to traditional water usage, water is essential for enhancing the quality of human existence and facilitating industrial and technological endeavors. An investigation was conducted on the contents of Cadmium (Cd), Copper (Cu), Iron (Fe), and Zinc (Zn) in drinking water from drilled wells in Surbakti Village, Karo District, employing Atomic Absorption Spectrophotometry (AAS) techniques. Sampling occurred during weeks 1, 2, 3, 4, and 5 and was subsequently digested with concentrated nitric acid until a volume of 15 mL was attained. The metal concentrations of Cd, Cu, Fe, and Zn were quantified using Atomic Absorption Spectroscopy (AAS) using a calibration curve. The findings indicated a concentration of Cd at 0.0031 mg/L, Cu at 0.0470 mg/L, Fe at 0.2741 mg/L, and Zn at 0.2929 mg/L. In this instance, Cd produced a greater concentration of drinking water standards compared to Cu, Fe, and Zn. Nonetheless, it nonetheless met the drinking quality standards established by Regulation Minister of Health No. 492/Menkes/Per/VII/2010.

Accumulation of mineral nutrients in fruit peel and pulp of loquat (Eriobotrya japonica) cultivars during fruit developmental stages

The experiment was conducted during 2023 at Punjab Agricultural University, Ludhiana, Punjab to assess the changes of mineral nutrients in peel and pulp of loquat cultivars at four developmental stages to explore its nutraceutical potential. During the development of loquat fruits, K and Zn content both in peel and pulp showed increasing trend from 60–92 DAFS. Similarly, Ca content in loquat peel, Fe and Mn content in pulp also exhibited increasing trend. While P, Cu and Mg content showed a decreasing trend in both peel and pulp. Likewise, Ca content in loquat pulp, Fe and Mn content in peel decreased from 60–92 DAFS. This study provides an insight regarding the accumulation of mineral nutrients in fruit peel and pulp in loquat cultivars during four fruit developmental stages which could be helpful for exploring its nutraceutical potential.

Potentiality of Amaranthus viridis (L.) to accumulation of heavy metals and its relation to protein profile

The present study was undertaken to assess the levels of heavy metals (Cd, Fe, Ni and Zn) in soil and plant parts. The phytoremediation potential of Amaranthus viridis (amaranth) was determined by calculating the bioconcentration factor (BCF) and translocation factor (TF). Soil and plant samples were collected from eight different sites in their native habitats, distributed along Ismailia irrigation canal located in the east of the Nile Delta region, Egypt. Roots of amaranth had the higher concentrations of Cd, Fe and Ni means which were 2.75, 547.3 and 7.25 mg g-1 DW at sites SH8, SH6 and SH4 respectively, as compared to the other sampling sites. Whereas, shoots had the higher concentrations of Zn (283.6 mg g-1 DW) at site SH5. All sites were found with BCF more than 1 for all heavy metals. Except for Zn, TF values of Cd, Fe and Ni at all sites were lower than one. Depending on BCF and TF results, amaranth showed significant potential for phytostabilization of Cd, Fe and Ni and phytoextraction of Zn as well. Moreover, the protein profile showed different bands with varied molecular weights. Both relationships between studied accessions and similarity were elucidated, with high similarity (96% between SH2 and SH3 accessions), lowest similarity (72% between SH4 and SH8) and degree of polymorphism calculated as 62.5%. The variation in the similarity index may be due to the induction of a variety of proteins under heavy metal stress and also ecological features in various sites that cause protein polymorphism.

Performance of soybean and corn in sandy soil subjected to increasing doses of micronutrients

At a global level, it is estimated that between 30% and 50% of agricultural production is influenced by the use of commercial fertilizers. The objective of this study was to evaluate the performance of soybean and corn subjected to doses of fertilizers containing multiple micronutrients. The experiment was conducted on the Água Limpa Araras property, in the 2022/2023 season. The experimental design adopted was randomized blocks, consisting of six treatments and four replicates, totaling 24 experimental units. Treatments were Fert Micro BR 12 fertilizer doses of: 0; 25; 50; 75; 100 and 125 kg ha-1. Leaf B, Mn and Zn contents were within the range considered ideal for soybean and corn crops, except in the corn crop, where the leaf Mn content in the control treatment and at a dose of 25 kg ha-1. Soybean and corn responded to the application of fertilizer containing multiple micronutrients. Soybean responded linearly with the increase in the dose of fertilizer containing multiple micronutrients, reaching a grain yield of 5,535 kg ha-1 with a dose of 125.0 kg ha-1. For corn, the maximum estimated dose of fertilizer containing multiple micronutrients was 115.8 kg ha-1, with grain yield of 12,454.48 kg ha-1.

A Systematic Review and Meta-Analysis of the Sustainable Impact of Sewage Sludge Application on Soil Organic Matter and Nutrient Content

The increasing scarcity of natural resources makes the linear production model unsustainable, highlighting the need for more sustainable practices under the umbrella of circular economic principles. Sewage sludge emerges as a promising solution to provide soil organic matter (SOM) and nutrients. This meta-analysis evaluated the impacts of three levels of sludge application (low, medium, and high) on organic matter (OM), nitrogen (N), phosphorus (P), copper (Cu), and zinc (Zn) contents, considering different areas and experimental conditions worldwide. The analysis included 37 studies and 355 comparisons, after screening 7625 records, following the 2020 PRISMA protocol. The effects of sludge concentrations, continents, and types of experiment (field or greenhouse) were evaluated. Sewage sludge application significantly increased OM, N, Cu, and Zn levels, mainly at medium and high rates. The largest effects were observed in greenhouses, suggesting variation by location and environment. Moderators explained a part of the variation in the results, but the residual heterogeneity test revealed that there is still unexplained variability.

Effect of Methods of Establishment and Zinc Management on Growth and Yield of Rice (Oryza sativa L.)

The field experiment was conducted at Shradhay Bhagwati Singh Agriculture Research Farm (Hajipur), Chandra Bhanu Gupta Krishi Snatkottar Mahavidyalaya, B.K.T., Lucknow (Uttar Pradesh) during Kharif (rainy) season in 2023-24. The treatment consisted of three methods of establishment (M1 – Direct seeding in lines after pre-irrigation, M2 -Broadcast of sprouted seed on puddled soil , M3 – System of Rice intensification (SRI) of (25 x 25cm) 12 days old seedling.) and five Zinc management practices (Zn0- Without zinc (control), Zn1- Zinc Sulphate ZnSo4@20kg ha-1 (Basal), Zn2- Foliar spray of Zn@0.5% at tillering and panicle initiation stage, Zn3- Seedling dipping in 2% ZnSO4+ 2 Foliar of Zn@0.5% at tillering and Panicle stage, Zn4- Seedling dipping in 2 % ZnSO4 solution+ Foliar spray of Zn@0.2% at tillering and panicle initiation stage) were tested in split-plot design with 3 replications. The Experimental site was silty loam having medium organic carbon (0.70%) and available nitrogen (270 kg ha-1), phosphorous (27 kg ha-1) and Potassium (262 kg ha1). All the growth parameters, yield attributes, yield, Zinc content and uptake of Zn into grains and straw, were increased significantly with SRI method (M3) followed by direct seeding in Lines after pre-irrigation (M2). Amongst zinc management, all the growth parameters and yield attributes of rice were maximum under Seedling dipping in 2% ZnSO4+ 2 Foliar of Zn@0.5% at tillering and panicle initiation stage, followed by Seedling dipping in 2 % ZnSO4 solution+ Foliar spray of Zn@0.2% at tillering and panicle initiation stage the maximum gross income of Rs 158938.18 ha-1 was accrued with (SRI method + T4) treatment combination. However, a combination of SRI method along with T3 treatment accrued the maximum net profit of Rs 107981.21 ha-1 and benefit: cost ratio of 2.08 which was followed by a combination of SRI method along with T4 with net income of Rs 107234.99 ha-1 and benefit cost ratio of 2.07.

Impact of soil legacy on plant–soil feedback in grasses and legumes through beneficial and pathogenic microbiota accumulation

Plants shape their surrounding soil, influencing subsequent plant growth in a phenomenon known as plant–soil feedback (PSF). This feedback is driven by chemical and microbial legacies. Here, we cultivated six crops from two functional groups, i.e., three grasses (Lolium, Triticum, and Zea) and three legumes (Glycine, Lens, and Medicago), to condition a living soil. Subsequently, the same species were sown as response plants on conspecific and heterospecific soils. We employed high-throughput sequencing in tandem with soil chemistry, including total organic matter, pH, total nitrogen, electrical conductivity, phosphorus, and macro and micro-nutrients. Our results showed that Glycine exhibited the strongest negative PSF, followed by Triticum and Zea, while Lolium displayed low feedback. Conversely, Lens demonstrated robust positive PSF, with Medicago exhibiting slight positive feedback. Soil chemistry significance indicated only higher Cl content in Triticum soil, while Lens displayed higher Zn and Mn contents. Microbial diversity exhibited no significant variations among the six soils. Although conditioning influenced the abundance of functionally important microbial phyla associated with each plant, no specificity was observed between the two functional groups. Moreover, each crop conditioned its soil with a substantial proportion of fungal pathogens. However, co-occurrence analysis revealed a strong negative correlation between all crop’s biomass and fungal pathogens, except Glycine, which exhibited a strong negative correlation with mutualists such as Arthrobacter and Bacillus. This underscores the complexity of predicting PSFs, emphasizing the need for a comprehensive understanding of plant interactions with both pathogens and mutualists, rather than focusing solely on host-specific pathogens.

Determination of priority control factors for risk management of heavy metal(loid)s in park dust in Mianyang City

In order to determine the priority control elements and sources of heavy metal(loid)s (HMs) pollution in park dust, this study collected dust samples from 25 parks in the urban area of Mianyang City and measured the contents of 10 HMs. Based on Monte Carlo simulation, the probabilistic pollution levels and ecological-health risks of HMs were assessed. We found that the average contents of Zn, Co, Pb, and Cr were much higher than their background values in local soil and were influenced by artificial activities. The pollution assessment found that 5 parks were moderately polluted. The comprehensive pollution of HMs in the dust was mainly caused by Zn and Cr, and industrial source was the main contributor to Zn and Cr pollution. The contribution of As, Co, and Pb to the comprehensive ecological risk was high, accounting for 54.6%. Co, Pb, and As were the priority control HMs of ecological risk, while mixed source and industrial source were the priority control sources. HMs presented potential carcinogenic health risks to both children and adults. The non-carcinogenic risk to adults was within safety level, while some parks showed non-carcinogenic risk to children, which should be paid attention to. The source-specific health risk assessment showed that Cr and As were the priority control HMs for human health, while mixed source and industrial source were the priority control sources.

Assessment of genetic biodiversity and association of micronutrients and agronomic traits using microsatellites and staining methods which accelerates high-micronutrients variety selections within different wheat groups

Evaluation of genetic biodiversity for micronutrients is crucial for breeding high-quality crops and addressing the negative impacts of mineral deficiencies. The objectives of this research were to assess genetic variation and the relationship between grain Fe and Zn levels and agronomic traits in a diverse collection of wheat varieties. Additionally, the study aimed to determine the correlation between microsatellite markers (SSR) and micronutrient quantities. A total of 42 genotypes (Iranian commercial cultivars, landraces, and Afghan and Swiss varieties) were evaluated over a two-year period. Fe and Zn levels were measured using two semi quantitative staining assays and atomic absorption spectrophotometry (AAS) facility. Semi-quantitative staining methods and AAS showed high correlations for micronutrient contents. Landraces exhibited higher Fe (63.79 mg/kg) and Zn (44.76 mg/kg) but lower grain yield compared with commercial cultivars. Heritability estimates ranged 53%-79.43%, suggesting that genetic variance played a higher contribution in the phenotypic variation of traits than environmental factors. Notably, Fe content displayed significant correlations with days to maturity. Canonical correlation analysis (CCA) revealed that Zn content was correlated with four agronomic traits. Evaluation of genetic diversity using SSR markers demonstrated high genetic variation among the genotypes tested. The analysis of polymorphism information content (PIC) indicated that SSR primers had an average PIC of 0.75, with the Xgwm192 primer exhibiting higher PIC than others. Several SSR markers revealed association with micronutrient content that can be used in marker-assisted selection (MAS) programs aimed at selection of high micronutrient genotypes. In conclusion, the findings underscored the substantial genetic diversity present in micronutrient levels among global wheat genotypes, the potential of landraces for micronutrients biofortification of wheat cultivars through cross hybridization, the utility of staining methods for screening high/low micronutrient genotypes, and use of microsatellite markers for marker-assisted breeding aiming to micronutrient improvement in breeding programs.

Impact of Acid Rain on Release Characteristics of Heavy Metals in Low-Sulfur Tailings with Strong Acid Neutralization Capacity: A Case Study from Northern Guangxi, China

Tailing ponds are major sources of heavy metal pollution. Previous studies primarily focused on tailings with high sulfur content, with limited attention to low-sulfur tailings. This study explored the release behavior of Pb, Zn, and Cd from low-sulfur tailings under simulated acid rain conditions, considering factors such as pH, particle size, and weathering degree. Samples were collected from a lead–zinc tailing pond in the karst regions of northern Guangxi, China. Batch leaching experiments indicated that even with high acid neutralization capacity (ANC = 166.57–167.45 kg H2SO4/t), substantial heavy metal leaching occurred under acidic conditions (pH 2–3), with Pb, Zn, and Cd concentrations increasing 4–6 times compared to neutral conditions. Leachate concentrations were slightly higher in coarser particles than in finer ones, while weathering further enhanced metal release, particularly for Cd. These findings suggest that acid neutralization alone may not be sufficient to prevent heavy metal leaching in low-sulfur tailings exposed to acid rain. However, due to the laboratory scale of this study, further validation through field-scale or mesocosm experiments is necessary to confirm the observed trends and assess their implications for environmental risk management in karst regions.

Standardization of Panchagavya for Enhanced Nutrient Content and Seed Germination in Sustainable Organic Farming

The detrimental effects of chemical-intensive agriculture have spurred interest in eco-friendly farming practices, particularly organic farming. Central to organic farming are organic manures, including various liquid organic formulations such as Panchagavya, which are rooted in Indigenous Technical Knowledge (ITK). Due to the variability in local production methodologies, there is a pressing need to standardize the production techniques of liquid organic manures, specifically Panchagavya, and to characterize their properties. The study standardizes Panchagavya production to reduce local variability. Eight ingredients were used, with 81 different combinations. Physical and chemical properties of prepared Panchagavya were analyzed, and principal component analysis was performed to determine optimal combinations for improved soil health and crop productivity. The nitrogen content of different combinations of Panchagavya ranged from 1.12% to 2.66%, phosphorus between 0.12% to 0.385%, potassium between 0.345% to 0.65%. The Ca content ranged between 186.3 mg L⁻¹ and 256.66 mg L⁻¹. Mg content the range was between 52.1 mg L-1 to 92.4 mg mg L-1, S varies between 0.08% and 0.3%, the Fe content in Panchagavya ranged from 49.7 mg L⁻¹ to 53.1 mg L⁻¹, Mn content ranged from 2.60 mg L⁻¹ to 5.05 mg L⁻¹, Zn content ranged from 4.1 mg L⁻¹ to 6.35 mg L⁻¹, and Cu content ranged from 12.50 mg L⁻¹ to 14.95 mg L⁻¹. with higher levels associated with increased quantities of cow urine, milk, curd, and ghee. Germination study indicated that Panchagavya positively affected seed germination and root growth increased from 3.45% to 114.66%. The growth hormone indole acetic acid values was between 56.6 µg mL⁻¹ and 104.19 µg mL⁻¹. Similarly, the gibberellic acid values ranged from 138.34 µg mL⁻¹ to 185.23 µg mL⁻¹. From the 81 treatment 10 best treatment was selected by principle component analysis of nutrient content of Panchagavya. Microbial analysis of selected Panchagavya demonstrated significant populations: bacteria (7.57 to 8.03 log cfu mL⁻¹), fungi (4.3 to 4.73 log cfu mL⁻¹), and actinomycetes (3.15 to 3.9 log cfu mL⁻¹). The presence of IAA and GA further substantiates its efficacy as an organic fertilizer. This research confirms that Panchagavya enhances nutrient content, microbial activity, and hormone levels, resulting in improved seed germination and root development. These findings highlight its potential as a sustainable alternative to chemical fertilizers, promoting organic farming practices and contributing to healthier soils.

Alterations in Zinc, Copper, and Iron Levels in the Retina and Brain of Alzheimer's Disease Patients and the APP/PS1 Mouse Model

ABSTRACT Transition metals like copper, iron, and zinc are vital for normal central nervous system function and are also linked to neurodegeneration, particularly in the onset and progression of Alzheimer's disease (AD). Their alterations in AD, identified prior to amyloid plaque aggregation, offer a unique target for staging pre-amyloid AD. However, analysing their levels in the brain is extremely challenging, necessitating the development of alternative approaches. Here, we utilised laser ablation-inductively coupled plasma-mass spectrometry and solution nebulisation-inductively coupled plasma-mass spectrometry to quantitatively measure Cu, Fe, and Zn concentrations in the retina and hippocampus samples obtained from human donors (i.e., AD and healthy controls), and in the APP/PS1 mouse model of AD, and Wild Type controls, aged 9 and 18 months. Our findings revealed significantly elevated Cu, Fe, and Zn levels in the retina (*p < 0.05, **p < 0.01, ***p < 0.001) and hippocampus (*p < 0.05, *p < 0.05, *p < 0.05) of human AD samples compared to healthy controls. Conversely, APP/PS1 mouse models exhibited notably lower metal levels in the same regions compared to WT mice, Cu, Fe, and Zn levels in the retina (**p < 0.01, *p < 0.05, *p < 0.05) and hippocampus (**p < 0.01, **p < 0.01, *p < 0.05). The contrasting metal profiles in human and mouse samples, yet similar patterns within each species' retina and brain, suggest the retina mirrors cerebral metal dyshomeostasis in AD. Our findings lay the groundwork for staging pre-AD pathophysiology through assessment of transition metal levels in the retina.

Evaluation of Industrial Hemp Cultivar and Biochar Rate to Remediate Heavy-Metal-Contaminated Soil from the Tar Creek Superfund Site, USA

Soil contamination by cadmium (Cd), lead (Pb), and zinc (Zn) at the Tar Creek superfund site in northeast Oklahoma, United States, remains a threat to the environment and local ecosystem. Phytoremediation with industrial hemp (Cannabis sativa L.) and the use of biochar (BC) have been independently shown to be effective methods to remediate heavy-metal-contaminated soils. The objective of this greenhouse study was to evaluate the effects of industrial hemp cultivar (‘Carmagnola’ and ‘Jinma’), biochar rate (0, 2, 5, and 10% by volume), soil contamination level (low, medium, and high), and their interactions on above- (AG) and belowground dry matter (DM) and AG tissue concentrations, as well as uptakes of Cd, Pb, and Zn after 90 days of growth in naturally contaminated soils from the Tar Creek superfund site. Aboveground DM was the largest (p < 0.01) in the low- (0.06 g cm−2) and smallest in the high-contaminated soil (0.03 g cm−2), and was unaffected (p > 0.05) by cultivar or BC rate. Averaged across BC rates, AG tissue Pb and Zn concentrations from the high-’Carmagnola’ and -’Jinma’ combinations were at least 2.4 times greater than from the other four soil–cultivar combinations. Averaged across cultivars, AG tissue Pb uptake in the high-5 and high-10% BC combinations were at least 2.7 times greater than in the high-0 and high-5% BC combinations, which did not differ. The results indicated that both ‘Carmagnola’ and ‘Jinma’ may be suitable choices for phytoremediation of mixed Cd-, Pb-, and Zn-contaminated soil when grown in combination with 5 or 10% (v/v) BC.

Typha domingensis (Pers.) Poir. ex Steud. Potential to Restore Contaminated Wetlands in Egypt

AbstractSeveral studies have reported Typha domingensis (Typhaceae) as a heavy metal (HM) hyperaccumulator. This study aims to assess the seasonal variations in the accumulation potential of T. domingensis (TD) for HM in polluted wetlands in Greater Cairo, Egypt. Sampling of fresh wild plants from the TD’s subterranean (Root and stem) and surface components were gathered from different polluted sites distributed in the canal of Ismailia and Nahia drain, as well as from the River Nile as an unpolluted site (control). The findings showed that pollution negatively affected the chemical characteristics of sediment and water. Except for the TD’s leaf area, there were significant seasonal variations in the growth characteristics (density, stem diameter, leaf length, and width, fresh and dry biomass). The subterranean parts stored higher amounts of HM than the aboveground shoots. Manganese (Mn) concentration (413.2 mg kg− 1) was greater in the roots of autumn plants, whereas their shoots recorded the highest Pb (225.8 mg kg− 1). Al, Cd, Cu, Fe, Ni, and Zn concentrations in summer plant roots (1499.9, 74.8,1356.1, 3948.8, 403.8, and 1294.2 mgkg− 1, respectively). The factor of metal bioaccumulation (BF) values, was high in TD plants growing in a polluted Ismailia canal, but translocation factor (TF) values for all measured elements were lower than one, except for Pb. Summer is the best season for TD growth to sequester high HM concentrations. The authors recommended that TD be employed to mitigate HM pollution in wetlands and restore them.

Hair and Blood Trace Elements (Cadmium, Zinc, Chrome, Lead, Iron and Copper) Biomonitoring in the Athletic Horse: The Potential Role of Haematological Parameters as Biomarkers

The aim of the present study was the evaluation of the bioaccumulation of cadmium (Cd), Zinc (Zn), Chrome (Cr), Lead (Pb), Iron (Fe) and Copper (Cu), in the blood, serum, tail and mane of horses from the industrialized area of Milazzo (Messina, Sicily), to understand the relationships between haematological parameters: Red Blood Cells (RBCs), White Blood Cells (WBCs), Haemoglobin (Hb), Haematocrit (Hct), Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), Mean Corpuscular Haemoglobin Concentration (MCHC), Platelets (PLTs) and the concentrations of trace elements. Blood and hair samples from 20 healthy Italian Saddle horses and water, hay and concentrates samples were obtained to determine the haemogram and mineral concentration using a Thermo Scientific iCAP-Q ICP-MS spectrometer. Descriptive analysis showed a higher concentration of Zn, Cr, Pb, Fe, and Cu in the blood and a higher concentration of Cd in the tail than other substrates. A positive correlation was found for Cr (p < 0.0001) and Zn (p < 0.01) between blood and serum substrates, for Zn (p < 0.001) between mane and tail and for Pb (p < 0.01) between blood and mane, while a negative correlation was observed for Cr (p < 0.01) between blood and tail. Results showed a close relationship between the bioaccumulation of certain trace elements in biological substrates and haematological parameters, which represent useful biomarkers suggesting further studies, given the role of haematological parameters in athletic horses.

Risk assessment and sources associated with potentially toxic elements in suspended particulate matter: A karst river perspective in active mining area

Study regionDaiyang River Basin, a typical karst river basin impacted by mining activities in Guizhou, Southwest China. Study focusRivers are fundamental components of regional water security, but they are facing potentially toxic elements (PTEs) pollution caused by mining activities. This study investigated the concentration, behavior, risks and sources of nine PTEs in suspended particulate matter (SPM) from mining-impacted karst rivers, which are essential for the safety and management of karst water environments. New hydrological insights for the regionThe contents of Cr, Ni, Cu, Zn, As, Cd, Sb and Hg exceeded the corresponding local soil background values, with Zn and Cu being the most important pollutants. These elements caused a very high potential toxicity risk to the basin and unacceptable carcinogenic and non-carcinogenic risks to the local residents. Correlation analysis and the positive matrix factorization (PMF) model indicated that Ni, Cd, Zn and Cu were mainly derived from mixed sources of geological background and anthropogenic activities (30.95 %), Hg, Sb, and As were related to coal mining and combustion sources (28.91 %), while Pb, As, Cr and Sb were mainly contributed by natural sources (40.15 %). Furthermore, mixed sources, mining-related sources and As were identified as priority control factors in the study area. These insights can provide powerful support for decision-makers to develop control policies and reduce PTEs pollution in karst areas.

Functional and structural analyses of IMP-27 metallo-β-lactamase: evolution of IMP-type enzymes to overcome Zn(II) deprivation.

IMP-type metallo-β-lactamases are di-Zn(II) enzymes that can inactivate a wide range of bicyclic β-lactam agents used in clinical practice. IMP-27 shares 82% amino acid sequence identity with IMP-1, the first IMP-type enzyme identified. Herein, we conducted structural determination, kinetic, and chelating agent resistance analyses of IMP-27. Once determined, IMP-27 was then compared to its mutant, namely, G262S, and IMP-1. Crystallographic structural analysis of IMP-27 showed an overall structure comparable to that of IMP-1 and other IMP-type enzymes; the positions of the zinc (Zn) ions varied across enzymes. Kinetic analysis showed that IMP-27 had lower catalytic efficiency against penicillins, ceftazidime, cephalexin, and imipenem than IMP-1; however, it had higher affinity and catalytic efficiency against meropenem, especially in the presence of Zn(II). This suggests that the catalytic site of IMP-27 is optimized to hydrolyze meropenem during molecular evolution at the expense of catalytic efficiency against penicillins. However, Zn(II) content analysis after EDTA treatment revealed no significant difference between enzymes. Moreover, analysis of IMP-27 mutants indicated that the differences in kinetic properties and chelator resistance between IMP-1 and IMP-27 were mainly due to an amino acid substitution at position 262.IMPORTANCEThe residue at position 262 has been reported as a key determinant of substrate specificity in IMP-type enzymes. Among more than 80 IMP-type metallo-β-lactamase (MBL) variants, IMP-27 was the first reported IMP-type MBL isolated from Proteus mirabilis. This enzyme has a glycine residue at position 262, which is occupied by serine in IMP-1. Compared with IMP-1, IMP-27 had a significantly higher affinity and catalytic efficiency against meropenem and improved metal-binding capacity, maintaining its activity under Zn(II)-limited conditions better than IMP-1. The analysis of the IMP-27 mutants indicated that differences between IMP-27 and IMP-1 were mainly due to an amino acid substitution at position 262. In the case of IMP-27, the G262S mutation optimized the catalytic site of IMP-27 for meropenem hydrolysis, at the expense of catalytic efficiency against penicillins.

Mitigating Mercury Accumulation and Enhancing Methylmercury Degradation in Rice: Insights from Zinc-Mercury Antagonism at Molecular Levels.

Zn as an essential element has the potential to protect against mercury (Hg) toxicity in rice. However, the antagonistic effects between Zn and Hg in rice and their mechanisms remain unknown. This study proposed a promising strategy for Zn application to mitigate Hg accumulation and toxicity in rice and revealed the underlying molecular mechanisms. The findings revealed that Zn supplementation significantly reduced the uptake and transportation of both IHg and MeHg in rice, thereby alleviating Hg phytotoxicity. In particular, Zn profoundly mitigated Hg-induced oxidative damage to rice, which was attributed to the redistribution of Hg and Zn in the root and Zn competing for binding sites on glutathione. The co-binding of Zn2+ and HgCH3+ within the same active sites of Zn transporters can promote the transfer of regions with a high charge density distribution at the highest occupied molecular orbital (HOMO) level. This process facilitates proton attack on the Hg-C bond, thereby enhancing MeHg demethylation in rice. By elucidating the molecular mechanisms of Zn, IHg, and MeHg interactions in rice, this study offers new insights for developing efficient strategies to mitigate Hg risks while boosting the Zn content in crops, thereby fortifying food safety.

Zinc Deficiency Leads to Reproductive Impairment in Male Mice Through Imbalance of Zinc Homeostasis and Inflammatory Response.

Zinc is an essential trace element crucial for growth and development and plays a significant role in male reproductive function. The aim of this study was explore the mechanism of male reproductive damage caused by different degrees of zinc deficiency. Thirty male ICR mice were randomly assigned to three groups: zinc-normal diet group (ZN, n = 10, Zn content = 30mg/kg), low zinc-deficiency diet group (LZD, n = 10, Zn content = 15mg/kg), and high zinc-deficiency diet group (HZD, n = 10, Zn content = 7.5mg/kg). The mice were maintained for 8weeks. At the end of the experiment, they were sacrificed, and their blood, testicular, and epididymal tissues were collected for further study. Zinc-deficient diet led to weight loss, testicular structural disorder, decreased semen quality, imbalance of zinc homeostasis, and inflammatory damage in mice. Semen quality, testosterone, serum Zn, testicular tissue Zn, testicular free Zn ions, Zrt-, Irt-like protein8 (ZIP8), Zrt-, Irt-like protein5 (ZIP5), and interleukin-10 (IL-10) were significantly decreased; zinc transporter 4(ZnT4), NF-κB p65, P-NF-κB p65, NLRP3, Caspase-8, and Caspase-3 were significantly increased in both LZD and HZD group mice. While compared with the LZD group, Zrt-, Irt-like protein13 (ZIP13), TNF-α, NF-κB p65, P-NF-κB p65, NLRP3, Caspase-1, and GSDMD were significantly increased in the HZD group. Both low and high zinc-deficiency diets can disrupt zinc homeostasis in mice, leading to heightened inflammatory responses, the activation of the NF-κB pathway, and increased apoptosis in testicular cells. Notably, a high zinc-deficiency diet led to an up-regulation of ZIP13 expression, exacerbated inflammation, and induced testicular pyroptosis, resulting in more severe reproductive damage in male mice.

Morphogenetic varieties of iron oxyhydroxides in shimmering smokers-diffusers of the Rainbow hydrothermal field (36°13′ N, 33°54′ W, Mid-Atlantic Ridge): LA-ICP-MS data for the development of halmyrolysis theory

Research subject. Iron oxyhydroxides covering and replacing the chimneys of shimmering water smokers-diffusers of the Rainbow hydrothermal field (MAR). Aim. To identify features of the concentration and associations of chemical elements in varieties of iron oxyhydroxides to recognize patterns of geochemical differentiation under conditions of halmyrolysis of sulfide chimneys-diffusers. Materials and methods. Samples were collected during a dive to a depth of 2300 m using the manual manipulator of the Mir-2 manned vehicle (travel No. 50, research vessel Akademik Mstislav Keldysh, 2005). Varieties of iron ohyhydroxides were identified using electron microscopes (REMMA-202М with LZ-5 Link system, Tescan Vega 3 sbu with an Oxford Instruments X-act energy-dispersive analyzer, and Jeol Superprobe 733 with an EDA Oxford Instruments INCAx-sight) and a powder X-ray diffractometer (SHIMADZU XRD-6000, CuK-α radiation with monochromator). Further, a mass spectrometry with inductively coupled plasma and laser ablation (LA-ICP-MS) analysis was conducted at the South Urals Federal Scientific Center of Mineralogy and Geoecology, Ural Branch of the Russian Academy of Sciences. Results. Microlayered goethite aggregates containing admixtures of barite, calcite, aragonite, native sulfur, covellite, sphalerite, and an X-ray amophoric oxyhydroxide phase of iron cover the shimmering diffusers. Towards the inner parts of the chimney walls, they are replaced by pseudomorphs of lepidocrocite after pyrite and pyrrhotite, and then by radial and bacteriomorphic crustifications of lepidocrocite. The use of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that goethite varieties have the increased contents of Zn and Co associated with other elements of medium-temperature hydrothermal fluids (Cd, Mn, Ni, Ga, Sn, Pb and Sb) in the absence of significant concentrations of a high-temperature hydrothermal association (Se, Bi, Te). The role of elements of seawater association (Mg, Na, K, Sr, U, V, As, Mo, Ni, P, B, W, Cs, REE) decreases from the surface layered goethite aggregates to crustification varieties of lepidocrocite. Different scenarios of accumulation under conditions of sulfide halmyrolysis and precipitation on local reduction barriers are proposed for elements with different valences (U, V, Mo, As, Cr, Eu). It is assumed that some of the microelements (Sr, V, As, P, REE) found in goethite are products of sorption on iron hydroxides or are part of invisible Fe-Ca hydroxyphosphates. Conclusion. The influence of sulfide halmyrolysis on the differentiation of chemical elements has been revealed.