New magnetic proxies to reveal source and bioavailability of heavy metals in contaminated soils.

Environmental magnetism plays an important role in monitoring heavy metal pollution, but most studies are confined to indicating only the levels of heavy metals using magnetic parameters. This study established new magnetic proxies for accurately depicting the sources and bioavailability of heavy metals in contaminated soils. We observed different relationships between χ and SIRM in the soils contaminated by non-ferrous metal smelting compared to those polluted by coal combustion and steel smelting. Furthermore, we found that the soft magnetic components (IRMsoft) in the soils were mainly controlled by the non-ferrous metal smelting activities, while the hard magnetic components (HIRM) might be affected by the iron erosion. These new magnetic proxies enriched the source composition spectrum and improved the accuracy of the source apportionment analyses (principal component analysis and positive matrix factorization), yielding a result that was comparable to that by Pb isotope fingerprinting. We also found strong relationships between magnetic parameters (especially IRMsoft) and bioavailable fractions of heavy metals, indicating that magnetic measurement may be a powerful tool for monitoring the bioavailability of heavy metals. This study expands the application fields of magnetism in environmental science research.

Efficient Pb(II) removal from contaminated soils by recyclable, robust lignosulfonate/polyacrylamide double-network hydrogels embedded with Fe2O3 via one-pot synthesis.

Soil heavy metal removal strategies are increasingly valued for effectively reducing contamination and preventing secondary pollution. In this work, a double network hydrogel (Fe2O3@LH), consisting of lignosulfonate (LS) and polyacrylamide with embedded Fe2O3 nanoparticles, was synthesized successfully via a one-pot method and subsequently applied to adsorb lead (Pb) from contaminated soil. Incorporating Fe2O3 into the hydrogel enhances the adsorption capacity of Fe2O3@LH for Pb(II). The Fe2O3@LH hydrogel demonstrates a maximum Pb(II) adsorption capacity of 143.11 mg g-1, with Pb(II) removal mechanisms involving electrostatic adsorption, cation exchange, precipitation reactions, and the formation of coordination complexes, achieving a 22.3 % maximum removal efficiency in soil cultivation experiments. Additionally, the application of Fe2O3@LH markedly reduces the concentrations of cadmium (Cd) and arsenic (As) in the soil, meanwhile enhances the levels of total nitrogen (TN), soil organic matter (SOM), and cation exchange capacity (CEC) by 23.1 %, 10.6 %, and 16.9 %, respectively. Following 90 days of continuous application in the soil, the recovery rate of Fe2O3@LH remains above 75 %. The toxicity assay using zebrafish larvae indicates that Fe2O3@LH demonstrates good biosafety. This study demonstrates the considerable potential of Fe2O3@LH hydrogel for practical application in reducing Pb(II) levels in contaminated soil.

Levels of trace elements in the blood of chick gulls from the English Channel: Spatial and trophic implications.

Anthropogenic activity has disturbed the natural distribution and circulation of trace elements in the environment. This has led to increased background levels of numerous elements, causing global pollution. In this context, seabirds are relevant bioindicators of environmental contamination. This study focuses on the ecological factors that influence the concentrations of 14 trace elements in the blood of the chicks of three sympatric gull species from the French coast of the English Channel. Between 2015 and 2017, 174 birds were sampled in the industrialised Seine Estuary (in the city of Le Havre and on Ratier Island) and in the remote Chausey Islands, 200 km to the west. We also considered the Se:Hg molar ratio using Hg concentrations in those birds. Ag and V concentrations were below the quantification limit in all cases, while the fraction of non-quantified samples was higher than 30 % for Cd, Cr and Ni. Among the elements quantified in the samples, the lowest concentrations were noted for Co and the highest for Fe, building the following order: Co < Cd < Ni < Mn ≤ Pb < Cr < Hg < Cu < Se < As < Zn < Fe. No unanimous scheme of concentrations among elements, species and sites existed. Similarly, different models were fitted and different factors were significant for different species and elements. We observed the biomagnification of As and the biodilution of Pb. Pb concentrations were also highest in the industrial site in the city of Le Havre. Despite the high proportion of non-quantified samples for Cd, Cr and Ni, we continued to notice higher concentrations in the marine environment of the Chausey Islands. Concentrations of some elements clearly revealed habitat dependence. In some cases the Se:Hg molar ratio was lower than 4, a threshold for diminishing Hg toxicity by Se.

Progress of Hole-Transport Layers in Mixed Sn-Pb Perovskite Solar Cells.

Hybrid organic-inorganic lead halide perovskite solar cells (PSCs) have rapidly emerged as a promising photovoltaic technology, with record efficiencies surpassing 26%, approaching the theoretical Shockley-Queisser limit. The advent of all-perovskite tandem solar cells (APTSCs), integrating Pb-based wide-bandgap (WBG) with mixed Sn-Pb narrow-bandgap (NBG) perovskites, presents a compelling pathway to surpass this limit. Despite recent innovations in hole transport layers (HTLs) that have significantly improved the efficiency and stability of lead-based PSCs, an effective HTL tailored for Sn-Pb NBG PSCs remains an unmet need. This review highlights the essential role of HTLs in enhancing the performance of Sn-Pb PSCs, focusing on their ability to mitigate non-radiative recombination and optimize the buried interface, thereby improving film quality. The distinct attributes of Sn-Pb perovskites, such as their lower energy levels and accelerated crystallization rates, necessitate HTLs with specialized properties. In this study, the latest advancements in HTLs are systematically examined for Sn-Pb PSCs, encompassing organic, self-assembled monolayer (SAM), inorganic materials, and HTL-free designs. The review critically assesses the inherent limitations of each HTL category, and finally proposes strategies to surmount these obstacles to reach higher device performance.

Significant lead isotope 'fractionation' in maize records plant lead uptake, transfer, and detoxification mechanisms.

Lead isotope analysis is the main method to trace the sources and cycling of Pb in the biosphere system. The linchpin of such application hinges on the assumption that there is negligible or no biologically mediated isotopic fractionation of Pb occurs in the environment. However, recent measurements by high-precision multi-collector mass spectrometry revealed that biological isotope fractionation of heavy mass elements is a prevalent phenomenon. This study shows that compared with the Pb sources, the maize plant (Zea mays L.) organs exhibit a wider range of Pb isotope compositions and a depletion of radioactive Pb isotopes (206Pb, 207Pb, and 208Pb). Moreover, three independent studies consistently indicate that the 206Pb/207Pb ratio of maize organs varies as root/leaf > stem/grain, reflecting a continuous loss of light Pb isotopes during transportation. The conventional wisdom fails to account for these phenomena, suggesting that maize may undergo Pb isotope fractionation during the absorption and transportation of Pb. However, compared with other non-traditional metal isotopes, Pb isotope exhibits a more significant fractionation magnitude. We tentatively attribute this fractionation to the Pb tolerance mechanism of maize and its selective absorption of various forms of Pb, which requires further research to validate. Findings from this study mandate caution in future Pb source tracing in plants using Pb isotope methods and open up applications in using Pb isotopic fractionation to track Pb uptake and transfer pathways and decipher the associated detoxification mechanisms in plants.

A novel sample pre-screening methodology for accurate in situ U-Pb dating of zircon crystals.

Internal inhomogeneity of the zircon crystals makes it difficult to date succedent geological processes. To overcome this limitation, a four-step pre-examination method is suggested before LA-ICP-MS based in situ U-Pb age determination of zircon crystals: 1. determination of morphology types of zircon, 2. description of internal textural patterns of zircon, 3. identification of mineral inclusions in zircon, 4. characterization of the structural state and chemical composition of zircon zones/areas. The novel four-step pre-examination protocol integrates established and partially established methods into comprehensive analytical techniques approach that enhances U-Pb dating. The paper demonstrates the effectiveness of this method using examples of zircons derived from granitoid rocks of the Variscan collision zone from the Mórágy Complex in southern Hungary and the Rastenberg Pluton in northern Austria. The study revealed that the areas of the primary textures within zircon crystals (growth zoning ± xenocrystic core, sector zoning) represent the effect of the primary magmatic event from both locations. The xenocrystic core suggests antecedent crustal origin. The secondary texture (convolute zoning) of zircon crystals reflects the post-magmatic event. It causes an overprinting of age data, highlighting the importance of a four-step pre-examination methodology in clarifying and separating nearly coeval geological processes. For age dating, 80 % of the core, 90 % of growth, sector zoning, and 100 % of convolute zoning of studied zircon crystals were appropriate. The suggested method can also be applied to U-Pb age dating of other mineral phases (allanite, apatite, titanite, rutile, xenotime, monazite) separated from igneous and sedimentary or metamorphic rocks.

Preclinical Investigation of [212Pb]Pb-DOTAM-GRPR1 for Peptide Receptor Radionuclide Therapy in a Prostate Tumor Model.

The role of gastrin-releasing peptide receptor (GRPR) in various diseases, including cancer, has been extensively studied and has emerged as a promising therapeutic target. In this study, we successfully achieved the use of [212Pb]Pb-DOTAM-GRPR1, comprising the α-particle generator, 212Pb, combined with a GRPR-targeting peptide, GRPR1, in a prostate cancer model. Methods: Pharmacokinetics, toxicity, radiation dosimetry, and efficacy were assessed in GRPR-positive prostate tumor-bearing mice after intravenous administration of [212Pb]Pb-DOTAM-GRPR1 (where DOTAM is 1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane). Results: Preclinical studies have shown tumor targeting of up to 5 percent injected dose per gram over 24 h, and optimization of the drug formulation and quantity has led to minimized oxidation and off-target binding, respectively. Particularly, an increase in peptide amount from 28 to 280 ng was shown to reduce off-target uptake, especially at the level of the pancreas, by about 30%. Furthermore, dosimetry studies confirmed the kidney as the dose-limiting organ, and toxicity studies revealed that a nontoxic dose of up to 1,665 kBq could be injected into mice. Efficacy studies indicated a median survival time of 9 wk in the control group, which received only a buffer solution, compared with 19 wk in the group that received 4 injections of 370 kBq at 3-wk intervals. Conclusion: Taken together, these combined data demonstrate the safety, tolerability, and efficacy of [212Pb]Pb-DOTAM-GRPR1, thus warranting further exploration in clinical trials.

Revisiting biochemical pathways for lead and cadmium tolerance by domain bacteria, eukarya, and their joint action in bioremediation.

With the advent rise is in urbanization and industrialization, heavy metals (HMs) such as lead (Pb) and cadmium (Cd) contamination have increased considerably. It is among the most recalcitrant pollutants majorly affecting the biotic and abiotic components of the ecosystem like human well-being, animals, soil health, crop productivity, and diversity of prokaryotes (bacteria) and eukaryotes (plants, fungi, and algae). At higher concentrations, these metals are toxic for their growth and pose a significant environmental threat, necessitating innovative and sustainable remediation strategies. Bacteria exhibit diverse mechanisms to cope with HM exposure, including biosorption, chelation, and efflux mechanism, while fungi contribute through mycorrhizal associations and hyphal networks. Algae, especially microalgae, demonstrate effective biosorption and bioaccumulation capacities. Plants, as phytoremediators, hyperaccumulate metals, providing a nature-based approach for soil reclamation. Integration of these biological agents in combination presents opportunities for enhanced remediation efficiency. This comprehensive review aims to provide insights into joint action of prokaryotic and eukaryotic interactions in the management of HM stress in the environment.

Unveiling the release mechanism of potentially toxic elements from Pb/Zn smelter contaminated soils under the coupled effects of freeze-thaw and acidification: Insights from mineralogical analysis.

Most Pb/Zn smelter contaminated sites in China are often encountered natural phenomenon known as freeze-thaw (F-T) cycles and acid rain. However, the coupled effects of F-T cycles and acidification on the release behavior of potentially toxic elements (PTEs) from soils remains unclear. A mechanistic study on PTEs release from soils was conducted by revealing the physicochemical weathering characteristics of minerals under F-T cycles combined with acidification. The results from F-T test indicated that among F-T parameters, F-T frequency were the more important factors influencing PTEs release, with the corresponding contribution ranges of 21.20-94.40 %. As pH decreased, the leaching concentrations of As, Cd, Cu, Mn, Pb and Zn did not increase under the same F-T frequency. As F-T frequency increased, the leaching concentrations of these studied PTEs also did not increase under the same pH condition. Microstructure characteristics revealed that the soils were a complex system with multi-mineral aggregates, which had experienced complex physicochemical weathering after F-T combined with acidification treatment. Combined with geochemical modeling results, PTEs release was found to be mainly influenced by the microstructure damage and proton corrosion of minerals, while little affected by their precipitation and dissolution. The mutual coupling relationships of mineral weathering and PTEs release were conducive to the better understanding of the migration behavior of PTEs in contaminated sites under complex environment scenarios. The present study results would provide theoretical instruction and technical support for the longevity evaluation of multi-metal stabilization remediation.

A chemometric approach using I-optimal design for optimising Pb(II) removal using bentonite-chitosan composites and beads.

This paper reports adsorption studies of Pb(II) ions onto Bentonite-Chitosan (Bt-Ch) composites or beads when using an I-optimal design experiment approach. Three adsorption factors (pH, adsorbent dosage, and initial concentration) were optimised whilst simultaneously investigating multiple adsorbents. The Bt-Ch composites and beads (type A and B) adsorbents were made using weight ratios 90%/10% and differed characteristically due to their preparation methods of solution blending and precipitation, respectively. A batch procedure was used for adsorption experiments, and the amounts of Pb(II) ions (adsorbed onto Bt-Ch composites/beads) were analysed using inductively coupled plasma optical emission spectrometry (ICP-OES). Adsorption experimental parameters were analysed and optimised by using a response surface method (I-optimal design) generated from Design-Expert® 13.0 software. The main achievements of this study were to intensify the understanding and application of I-optimal experimental designs, which allow simultaneous determination of adsorption capacities and efficiencies across multiple adsorbents in an economical manner. A reduced quadratic model provided the best fit for the experimental data and exhibited minimal deviation between predicted and experimental values. This was evidenced by the very small covariance (CV) values of 1.81% and 1.33% observed for adsorption capacity and adsorption efficiency, respectively, also suggesting high reproducibility. It was observed that the adsorption factors studied (pH, adsorbent dose, and initial concentration) have a more pronounced effect on the adsorption capacity (F-value = 714.37) compared to adsorption efficiency (F-value = 140.62). Adsorbent dosage was found to have the greatest effect on adsorption capacity, while the initial pH of Pb(II) solution had the greatest effect on adsorption efficiency. Under optimal conditions, the adsorption capacities of beads-A (73.2 mg/g) and beads-B (77.6 mg/g) were found to be higher than that of the corresponding composite (51.7 mg/g). Whilst the optimum adsorption efficiency values for all three adsorbents were ∼100% (with ranges of pH 2-5, initial concentrations 50-200 mg/L, and adsorbent dosage 0.05-0.5 mg). The desirability indexes for the optimised conditions for these respective responses (and each adsorbent) were found to be within the ranges of 0.892-0.974 and 0.945-0.967 for adsorption capacity and adsorption efficiency, respectively. These high desirability index values for both responses indicate that the optimised conditions lead to very good performance for both measures. The information obtained in this study provides detailed understanding of the adsorption phenomena of the adsorbents studied. It gives confidence in the use of I-optimal designs to be applied as a chemometric tool for the specific adsorbents studied herein and others.

Exposure to Multiple Metal(loid)s and Hypertension in Chinese Older Adults.

Evidence about effects of metal(loid)s on hypertension among adults is insufficient. The aim of our study was to evaluate the individual and joint associations between seven selected metal(loid)s and hypertension, including lead (Pb), manganese (Mn), nickel (Ni), arsenic (As), cadmium (Cd), chromium (Cr), and vanadium (V)) in Chinese older adults. This study included 1009 older adults, and the blood concentrations of seven metal(loid)s were evaluated by inductively coupled plasma mass spectrometry (ICP-MS). The following conditions were considered as hypertension: (1) either systolic blood pressure ≥ 140 mm Hg or diastolic blood pressure ≥ 90 mm Hg, (2) a self-reported history of hypertension, or (3) currently taking antihypertensive medications. Logistic regression was utilized to investigate the association between individual metal(loid) and hypertension, while Bayesian kernel machine regression (BKMR) was employed to investigate the association of the metal(loid) mixture with hypertension. Adjusted single-metal(loid) model showed a significant positive association between Pb and hypertension (OR = 1.24, 95%CI = 1.03-1.50). This significant association still existed in multi-metal(loid) model (OR = 1.22, 95%CI = 1.01-1.47). BKMR further indicated a positive linear association of Pb with hypertension. The metal(loid) mixture was positively associated with hypertension in older adults, although not significant. Within the mixture, Pb had the highest posterior inclusion probabilities value (PIP = 0.9192). There were multiplicative interactions of Pb and Mn on hypertension. In addition, Pb and Mn had additive effects on the association of other blood metal(loid)s with hypertension. The associations of multiple metal(loid)s with hypertension are dependent on diabetes, areas, age, and BMI. The metal(loid) mixture exposure may contribute to hypertension in Chinese older adults, mainly driven by Pb and interactions of Pb and Mn. Reducing exposure to these metal(loid)s may prevent hypertension among older adults, which is especially true for those living with diabetes.

Multi-Functional Silole Hole Transport Layer for Efficient and Stable Lead-Tin Perovskite and Tandem Solar Cells.

Despite high theoretical efficiencies and rapid improvements in performance, high-efficiency ≈1.2 eV mixed Sn-Pb perovskite solar cells (PSCs) generally rely on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT: PSS) as the hole transport layer (HTL); a material that is considered to be a bottleneck for long-term stability due to its acidity and hygroscopic nature. Seeking to replace PEDOT: PSS with an alternative HTL with improved atmospheric and thermal stability, herein, a silole derivative (Silole-COOH) tuned with optimal electronic properties and efficient carrier transport by incorporating a carboxyl functional group is designed, which results in an optimal band alignment for hole extraction from Sn-Pb perovskites and robust air and thermal stability. Thin films composed of the Silole-COOH exhibit superior conductivity and carrier mobility compared to PEDOT: PSS, in addition to reduced nonradiative quasi-Fermi-level splitting losses at the HTL/perovskite interface and improved quality of Sn-Pb perovskite. Replacement of PEDOT: PSS with Silole-COOH leads to 23.2%-efficient single-junction Sn-Pb PSCs, 25.8%-efficient all-perovskite tandems, and long operating stability in ambient air.

Corrigendum: Good manufacturing practice-grade generation of CD19 and CD123-specific CAR-T cells using piggyBac transposon and allogeneic feeder cells in patients diagnosed with B-cell non-Hodgkin lymphoma and acute myeloid leukemia.

[This corrects the article DOI: 10.3389/fimmu.2024.1415328.].

One-Pot Synthesis of Biochar from Industrial Alkali Lignin with Superior Pb(II) Immobilization Capability.

This study synthesized biochar through a one-pot pyrolysis process using IALG as the raw material. The physicochemical properties of the resulting biochar (IALG-BC) were characterized and compared with those of biochar derived from acid-treated lignin with the ash component removed (A-IALG-BC). This study further investigated the adsorption performances and mechanisms of these two lignin-based biochars for Pb(II). The results revealed that the high ash content in IALG, primarily composed of Na, acts as an effective catalyst during pyrolysis, reducing the activation energy and promoting the development of the pore structure in the resulting biochar (IALG-BC). Moreover, after pyrolysis, Na-related minerals transformed into particulate matter sized between 80 and 150 nm, which served as active adsorption sites for the efficient immobilization of Pb(II). Adsorption results demonstrated that IALG-BC exhibited a significantly superior adsorption performance for Pb(II) compared to that of A-IALG-BC. The theoretical maximum adsorption capacity of IALG-BC for Pb(II), derived from the Langmuir model, was determined to be 809.09 mg/g, approximately 40 times that of A-IALG-BC. Additionally, the adsorption equilibrium for Pb(II) with IALG-BC was reached within approximately 0.5 h, whereas A-IALG-BC required more than 2 h. These findings demonstrate that the presence of inorganic mineral components in IALG plays a crucial role in its resource utilization.

Source apportionment and emission projections of heavy metals from traffic sources in India: Insights from elemental and Pb isotopic compositions.

The study investigates the sources of metals in urban road dusts using elemental concentration and Pb isotopic ratios. The elemental concentrations are also utilized to determine the present heavy metal emissions as well as projected emissions till 2045. Bayesian mixing model for source apportionment highlights the significant contributions of both exhaust and non-exhaust sources to the metal-enriched urban road dusts, with each contributing approximately 40 %. Emission analysis reveals that India's projected electric vehicle (EV) penetration may not be sufficient to suppress the metal emissions from vehicular exhausts. Further challenge is posed by high metal concentrations in the non-exhaust sources, that dominates the emission of some metals compared to exhaust sources. If the metal concentrations remain unchanged, the emission analysis predicts alarming increases in total emissions from all the exhaust and non-exhaust sources by 174 %, 176 %, 163 % and 184 % for Ni, Cu, Zn and Pb, respectively, from 2022 to 2045. Thus, it is crucial to reduce the metal concentrations in traffic emission sources and also impose better regulatory measures to improve the urban metal pollution scenario.

Perylene Diimide-based Fluorescent Aptasensor for Quantitative Analysis of Pb2+ Based on Terminal Deoxynucleotidyl Transferase-assisted Formation of Elongated Aptamer and Gold Nanoparticles.

Due to the exceedingly poisonous properties of Pb2+, it is imperative to conduct a thorough assessment of its quantity in both biological and environmental samples, as this is crucial for safeguarding public health. This study describes an economic turn-off fluorescent aptasensor for the quantitative analysis of Pb2+ employing 3,4,9,10-perylenetetracarboxylic acid diimide (PTCDI) as a cost-effective fluorophore, gold nanoparticles (AuNPs) as separating agent and an elongated aptamer as both targeting agent and PTCDI loading site. The fundamental principle of the suggested fluorescent aptasensor, which is based on PTCDI, relies on detecting variations in the fluorescence intensity of PTCDI when an elongated aptamer (as single-stranded DNA) is present or absent. The advanced aptasensor is advantageous due to the elongation of the lead aptamer sequence length induced by terminal deoxynucleotidyl transferase (TdT), resulting in enhanced sensitivity. The presence of Pb2+ and the centrifugation process causes the separation of the poly A-modified aptamer/Pb2+ conjugate from the poly T sequence. Hence, the interaction of PTCDI with the poly A moiety in the modified aptamer leads to a decrease in its fluorescence emission. The findings showcased that the fluorescent aptasensor exhibited exceptional specificity towards Pb2+ ions, while the biosensing platform accomplished an impressive detection limit of 3.7 pM. Moreover, the suggested aptasensor utilizing PTCDI exhibits a commendable capability in quantitatively analyzing Pb2+ within human serum samples and mineral water.

Titanite petrochronological data across the continental crust section exposed in Val d'Ossola (Ivrea-Verbano Zone, Italy).

Titanite-bearing calc-silicates and mafic gneisses, metamorphosed under amphibolite- to granulite-facies conditions, crop out in Val d'Ossola area (Ivrea-Verbano Zone, Italy). The Ivrea-Verbano Zone represents an exhumed section of the pre-Alpine middle to lower continental crust which escaped the Alpine subduction, thus provides a unique opportunity to study continental crustal processes and evolution. Among several samples, three, collected from different locations, were chosen for detailed analyses of titanite. Petrochronology of titanite was performed with Laser ablation split-stream (LASS) technique on petrographic thin sections. Petrochronological results on titanite do not define clear correlations with chemistry except for one sample. Rare earth elements (REE) patterns of titanite from the three samples are apparently different in terms of average concentration (i.e., lower or upper 1000 times CI), shapes and occurrence or absence of Eu negative anomaly. Al/Fe vs ΣLREE and Fe content vs Zr/Y plots show that the studied samples coincide with metamorphic rock field deriving from calc-silicates and mafic protoliths, as previously demonstrated in literature. Any compilations of petrochronological data on titanite from the metamorphic volcano-sedimentary sequence of Val d'Ossola can be found in literature. Therefore, these data represent a new insight on an accessory mineral phase whose significance and scientific interest are rising in the last years. Future studies of the evolution of these kinds of rock, widespread in the high-grade metamorphic basements, will benefit from these data as a term of comparison.

Understanding the stability and dynamics of influenza a H5N1 polymerase PB2 CAP-Binding domain in complex with natural compounds for antiviral drug discovery.

Influenza A virus, particularly the H5N1 strain, poses a significant threat to public health due to its ability to cause severe respiratory illness and its high mortality rate. Traditional antiviral drugs targeting influenza A virus have faced challenges such as drug resistance and limited efficacy. Therefore, new antiviral compounds are needed to be discovered and developed. This study concentrated on examining the stability and behavior of the H5N1 polymerase PB2 CAP-binding domain when interacting with natural compounds, aiming to identify potential candidates for antiviral drug discovery. Through the virtual screening process, four lead compounds, ZINC000096095464, ZINC000044404209, ZINC000001562130, and ZINC000059779788, were selected, and these compounds showed binding energies -9.6, -9.4, -9.3, and -9.2 kcal/mol, respectively. When complexed with PB2, the ligand showed acceptable binding stability due to significant bond formation. However, during the 200ns MD simulation analysis, three (ZINC000096095464, ZINC000044404209, and ZINC000059779788) showed significant stability, which was proven by the trajectory analysis. The Rg-RMSD-based FEL plot showed significant structural stability due to stable conformers. The free-binding energy calculation also validates the stability of these complexes. This study offers valuable insights into the stability and dynamics of the H5N1 polymerase PB2 CAP-binding domain in complexes with natural compounds. These findings highlight the potential of these natural compounds as antiviral agents against the H5N1 influenza virus. Furthermore, this research contributes to the broader field of influenza virus treatment by demonstrating the effectiveness of computational methods in predicting and evaluating the stability and dynamics of potential drug candidates.

Photosystem modulation and extracellular silicification in green microalgae: Key strategies for lead tolerance and removal.

The escalating contamination caused by lead ions (Pb2⁺) and its harmful effects on all life forms has raised global concerns. Certain microalgae thrive in metal mining sites characterized by low pH and high concentrations of Pb2⁺, which are usually prohibitive for many microorganisms. Little is known about the mechanisms underlying the adaptation of such microalgae to these hostile conditions. In this study, we elucidated the adaptive strategies of the green microalga Micractinium belenophorum strain AUMW, isolated from a lead mining site, and its application for the removal of Pb+2. Results revealed that strain AUMW can efficiently tolerate up to 200 ppm of Pb+2 in an F/2 medium. Further experimental variables were optimized through response surface methodology (RSM), and 99.6 % removal of Pb2⁺ was achieved. Novel adaptive responses of strain AUMW to high levels of Pb2⁺ include: (i) activation of metal-protective response by modulation of quantum yield (F v /F m ) and non-photochemical quenching (NPQ) of photosystem II; (ii) extracellular silicification encapsulated cells of strain AUMW and altered cell morphology from oval to hexagonal; (iii) silicification prevented intracellular translocation of Pb+2; (iv) silicification boosted adsorption of Pb+2, thus enhanced its removal. This study offers new insights into the protective role of silicification in green microalgae and its potential for the removal of metals from metal-polluted sites, waste from energy storage battery industries, and spent batteries. It also provides a solid base to explore the genetic and metabolic pathways involved in the adaptation of strain AUMW to elevated levels of Pb+2.

Impact of Cd and Pb on the photosynthetic and antioxidant systems of Hemerocallis citrina Baroni as revealed by physiological and transcriptomic analyses.

KEY MESSAGE: Cd induces photosynthetic inhibition and oxidative stress damage in H. citrina, which mobilizes the antioxidant system and regulates the expression of corresponding genes to adapt to Cd and Pb stress. Cd and Pb are heavy metals that cause severe pollution and are highly hazardous to organisms. Physiological measurements and transcriptomic analysis were combined to investigate the effect of 5 mM Cd or Pb on Hemerocallis citrina Baroni. Cd significantly inhibited H. citrina growth, while Pb had a minimal impact. Both Cd and Pb suppressed the expression levels of key chlorophyll synthesis genes, resulting in decreased chlorophyll content. At the same time, Cd accelerated chlorophyll degradation. It reduced the maximum photochemical efficiency of photosystem (PS) II, damaging the oxygen-evolving complex and leading to thylakoid dissociation. In contrast, no such phenomena were observed under Pb stress. Cd also inhibited the Calvin cycle by down-regulating the expression of Rubisco and SBPase genes, ultimately disrupting the photosynthetic process. Cd impacted the light reaction processes by damaging the antenna proteins, PS II and PS I activities, and electron transfer rate, while the impact of Pb was weaker. Cd significantly increased reactive oxygen species and malondialdehyde accumulation, and inhibited the activities of antioxidant enzymes and the expression levels of the corresponding genes. However, H. citrina adapted to Pb stress by the recruitment of antioxidant enzymes and the up-regulation of their corresponding genes. In summary, Cd and Pb inhibited chlorophyll synthesis and hindered the light capture and electron transfer processes, with Cd exerting great toxicity than Pb. These results elucidate the physiological and molecular mechanisms by which H. citrina responds to Cd and Pb stress and provide a solid basis for the potential utilization of H. citrina in the greening of heavy metal-polluted lands.