High-throughput assessment of toxic effects of metal mixtures of cadmium(Cd), lead(Pb), and manganese(Mn) in nematode Caenorhabditis elegans

Exploring the impact of Agaricus bisporus on mitigating lead reproductive toxicity using the Caenorhabditis elegans model

Given that Agaricus bisporus, an edible mushroom, has demonstrated antioxidant properties, our investigation aimed to assess whether Agaricus bisporus could mitigate the toxic effects of lead (Pb) on Caenorhabditis elegans (C. elegans) model. A dose-response study was conducted involving Pb and Agaricus bisporus to determine appropriate doses. Subsequently, a co-exposure study utilizing C. elegans strains N2 and CL2166 was implemented, with groups designated as Control, Pb, Agaricus bisporus, and Pb + Agaricus bisporus. Our findings revealed that co-exposure to Pb + 100 mg/mL Agaricus bisporus resulted in reduced embryonic and larval lethality, increased brood size, and enhanced motility compared to nematodes exposed solely to Pb. Notably, our observations indicated a transfer of reproductive toxicity from nematode parents to their offspring. Thus, Agaricus bisporus may play a significant role in Pb detoxification, suggesting its potential as a natural antioxidant for neutralizing the detrimental effects of Pb on reproductive health.

The nematode Caenorhabditis elegans enhances tolerance to landfill leachate stress by increasing trehalose synthesis

The burgeoning issue of landfill leachate, exacerbated by urbanization, necessitates evaluating its biological impact, traditionally overshadowed by physical and chemical assessments. This study harnesses Caenorhabditis elegans, a model organism, to elucidate the physiological toxicity of landfill leachate subjected to different treatment processes: nanofiltration reverse osmosis tail water (NFRO), membrane bioreactor (MBR), and raw leachate (RAW). Our investigation focuses on the modulation of sugar metabolism, particularly trehalose-a disaccharide serving dual functions as an energy source and an anti-adversity molecule in invertebrates. Upon exposure, C. elegans showcased a 60-70% reduction in glucose and glycogen levels alongside a significant trehalose increase, highlighting an adaptive response to environmental stress by augmenting trehalose synthesis. Notably, trehalose-related genes in the NFRO group were up-regulated, contrasting with the MBR and RAW groups, where trehalose synthesis genes outpaced decomposition genes by 20-30 times. These findings suggest that C. elegans predominantly counters landfill leachate-induced stress through trehalose accumulation. This research not only provides insights into the differential impact of leachate treatment methods on C. elegans but also proposes a molecular framework for assessing the environmental repercussions of landfill leachate, contributing to the development of novel strategies for pollution mitigation and environmental preservation.

Nucleic Acid Aptamers Protect Against Lead (Pb(II)) Toxicity

Lead (Pb(II)) is a pervasive heavy metal toxin with many well-established negative effects on human health. Lead toxicity arises from cumulative, repeated environmental exposures. Thus, prophylactic strategies to protect against the bioaccumulation of lead could reduce lead-associated human pathologies. Here we show that DNA and RNA aptamers protect C. elegans from toxic phenotypes caused by lead. Reproductive toxicity, as measured by brood size assays, is prevented by co-feeding of animals with DNA or RNA aptamers. Similarly, lead-induced behavioral anomalies are also normalized by aptamer feeding. Further, cultured human HEK293 and primary murine osteoblasts are protected from lead toxicity by transfection with DNA aptamers. The osteogenic development, which is decreased by lead exposure, is maintained by prior transfection of lead-binding DNA aptamers. Aptamers may be an effective strategy for the protection of human health in the face of increasing environmental toxicants.

Modeling mixtures interactions in environmental toxicology

In the environment, organisms are exposed to mixtures of different toxicants, which may interact in ways that are difficult to predict when only considering each component individually. Adapting and expanding tools from pharmacology, the toxicology field uses analytical, graphical, and computational methods to identify and quantify interactions in multi-component mixtures. The two general frameworks are concentration addition, where components have similar modes of action and their effects sum together, or independent action, where components have dissimilar modes of action and do not interact. Other interaction behaviors include synergism and antagonism, where the combined effects are more or less than the additive sum of individual effects. This review covers foundational theory, methods, an in-depth survey of original research from the past 20 years, current trends, and future directions. As humans and ecosystems are exposed to increasingly complex mixtures of environmental contaminants, analyzing mixtures interactions will continue to become a more critical aspect of toxicological research.

High-levels of toxic elements and radioactivity in an abandoned sulphur mine: Insights on the origin and associated environmental concerns

Natural fibrous epsomite crystals containing high amounts of toxic and radioactive elements have recently been discovered in the abandoned sulphur mine of Perticara (Italy). In the present study, all the different matrices that characterize the Perticara mine (air, water, host-rock, minerals, and bitumen) were sampled and investigated employing a multi-analytical approach to define the distribution and origin of these hazardous elements. Water samples showed high Al, Fe, Pb, Mg, and Mn content but not radioactive elements. The bitumen sample showed a higher amount of 210Po and 210Pb (0.12 Bq/g and 0.11 Bq/g, respectively), compared to the host-rock and fibrous sericolite samples, but lower than fibrous epsomite crystals (210Po 5.59 Bq/g; 210Pb 5.93 Bq/g). A high 222Rn concentration was also detected in the tunnels and it is likely the source of both 210Po and 210Pb, which are in radioactive equilibrium, especially in epsomite. This latter mineral, being capable of capturing 210Po and 210Pb, can be used as a helpful mineral indicator for the presence of radioactive elements in similar environmental conditions. Moreover, our results also highlight a slight anomaly in the 40K and 226Ra content of the host-rock, probably derived from the evaporitic sediments of the rock succession. The current risk for humans linked to the mine environment is minor since the activity of the mine ended several decades ago. However, the results of this study must be taken into serious consideration for any future development of this area (e.g., industrial archaeology, farming, educational, scientific and touristic purposes), and represent the basis for the calculation of radiotoxicity and dose assessment, which is fundamental for the correct and safe management of the mining environment and neighbouring areas.

Recent Advances in Drug Discovery Toxicology

Major advances in scientific discovery and insights that stem from the development and use of new techniques and models can bring remarkable progress to conventional toxicology. Although animal testing is still considered as the "gold standard" in traditional toxicity testing, there is a necessity for shift from animal testing to alternative methods regarding the drug safety testing owing to the emerging state-of-art techniques and the proposal of 3Rs (replace, reduce, and refine) towards animal welfare. This review describes some recent research methods in drug discovery toxicology, including in vitro cell and organ-on-a-chip, imaging systems, model organisms (C. elegans, Danio rerio, and Drosophila melanogaster), and toxicogenomics in modern toxicology testing.

Bacteria pyruvate metabolism modulates AFB1 toxicity in Caenorhabditis elegans

Aflatoxin B1 (AFB1), the most potent mycotoxin and Group 1 human carcinogen, continues to pose a significant public health burden, particularly in developing countries. Increasing evidence has shown the gut microbiota as a key mediator of AFB1 toxicity through multiple interactive host-microbiota activities. In our previous study we observed that disturbances in bacterial pyruvate metabolism might have a significant impact on AFB1 in the host. To further investigate the impact of the pyruvate pathway on AFB1 toxicity in C. elegans, we engineered two bacterial strains (triple-overexpressed and triple-knockout strains with aceB, lpd, and pflB). Additionally, we employed two mutant worm strains (pyk-1 and pdha-1 mutants) known to affect pyruvate metabolism. Our results revealed that the co-metabolism of pyruvate by the host and bacterial strains synergistically influences AFB1 toxicity. Remarkable, we found that bacterial pyruvate metabolism, rather than that of the host, plays a pivotal role in modulating AFB1 toxicity in C. elegans. Our study sheds light on the role of gut microbiota involved in pyruvate metabolism in influencing AFB1 toxicity in C. elegans.

Simira cordifolia protects against metal induced-toxicity in Caenorhabditis elegans

Simira cordifolia (Hook.f.) Steyerm (Rubiaceae) is a vascular plant used in Northern Colombia as a source of pigments and wood. However, there is a lack of information regarding its pharmacology and toxicity. This research aimed to study the hydroalcoholic extract of Simira cordifolia as a protector against metal-induced toxicity in Caenorhabditis elegans. Preliminary phytochemical screening of the hydroalcoholic extract of S. cordifolia (HAE-Sc) was conducted using HPLC-ESI-QTOF. Wild-type N2 C. elegans larvae were exposed to different concentrations of HAE-Sc evaluating lethality (50-5000 μg/mL), growth, lifespan, resistance to heat stress, and its protective effect against Mercury (Hg)-, Lead (Pb)- and Cadmium (Cd)-induced lethality (50-1000 μg/mL). The main metabolites present in the extract were iridoids, β-carboline-alkaloids and polyphenols. Bioassays demonstrated that HAE-Sc exhibited low toxicity, with significant lethality (4.2% and 9.4%) occurring at 2500-5000 μg/mL. Growth inhibition reached up to 23.3%, while reproduction declined 13% and 17% at concentrations 500 and 1000 μg/mL, respectively. HAE-Sc enhanced the survival rate of the nematode under thermal stress by up to 79.8%, and extended the mean lifespan of worms by over 33% compared to control. The average lifespan was prolonged by 15.3% and 18.5% at 50 and 100 μg/mL HAE-Sc, respectively. The extract (1000 μg/mL) was able to reduce the death of C. elegans in the presence of heavy metals up to 65.9, 96.8% and 87% for Pb, Hg, and Cd, respectively. In summary, S. cordifolia shows potential protective effects in C. elegans against toxicity caused by heavy metals and heat.

The stage-specific toxicity of per- and polyfluoroalkyl substances (PFAS) in nematode Caenorhabditis elegans

Per- and Polyfluoroalkyl Substances (PFAS) are a diverse class of industrial chemicals that have been used for decades in industrial and commercial applications. Due to their widespread usages, persistence in the environment, and bioaccumulation in animals and humans, great public health concerns have been raised on adverse health risks of PFAS. In this study, ten PFAS were selected according to their occurrence in different water bodies. The wild-type worms were exposed to individual PFAS at 0, 0.1, 1,10, 100, and 200 μM, and the toxic effects of PFAS on growth, development, fecundity, and behavior at different life stages were investigated using a high-throughput screening (HTS) platform. Our results showed that perfluorooctanesulfonic acid (PFOS), 1H,1H, 2H, 2H-perfluorooctanesulfonamidoacetic acid (NEtFOSAA), perfluorobutanesulfonic (PFBS), and perfluorohexanesulfonic acid (PFHxS) exhibited significant inhibitive effects on the growth in the L4 larva and later stages of worms with concentrations ranging from 0.1 to 200 μmol/L. PFOS and PFBS significantly decreased the brood size of worms across all tested concentrations (p < 0.05), and the most potent PFAS is PFOS with BMC of 0.02013 μM (BMCL, 1.6e-06 μM). During adulthood, all PFAS induced a significant reduction in motility (p < 0.01), while only PFOS can significantly induce behavior alteration at the early larvae stage. Furthermore, the adverse effects occurred in larval stages were found to be the most susceptible to the PFAS exposure. These findings provide valuable insights into the potential adverse effects associated with PFAS exposure and show the importance of considering developmental stages in toxicity assessments.

Pollutants in aquatic system: a frontier perspective of emerging threat and strategies to solve the crisis for safe drinking water

Water is an indispensable natural resource and is the most vital substance for the existence of life on earth. However, due to anthropogenic activities, it is being polluted at an alarming rate which has led to serious concern about water shortage across the world. Moreover, toxic contaminants released into water bodies from various industrial and domestic activities negatively affect aquatic and terrestrial organisms and cause serious diseases such as cancer, renal problems, gastroenteritis, diarrhea, and nausea in humans. Therefore, water treatments that can eliminate toxins are very crucial. Unfortunately, pollution treatment remains a difficulty when four broad considerations are taken into account: effectiveness, reusability, environmental friendliness, and affordability. In this situation, protecting water from contamination or creating affordable remedial techniques has become a serious issue. Although traditional wastewater treatment technologies have existed since antiquity, they are both expensive and inefficient. Nowadays, advanced sustainable technical approaches are being created to replace traditional wastewater treatment processes. The present study reviews the sources, toxicity, and possible remediation techniques of the water contaminants.

Unraveling the complexities of Cd-aniline composite pollution: Insights from standalone and joint toxicity assessments in a bacterial community

Cadmium (Cd) and aniline frequently co-occur in industrial settings but have rarely been addressed as composite toxicants in terms of the overall toxicity despite extensive knowledge of the environmental impact of each individual pollutant. In this study, we attempt to assess the relation of individual and combined toxic effects of Cd and aniline using a bacterial consortium cultured from soils as a model system. Results showed that the consortial bacteria exhibited drastically stronger tolerance to stand-alone Cd and aniline in comparison to literature data acquired from single species studies. When occurring simultaneously, the joint toxicity displayed a concentration-dependent behavior that wasn't anticipated based on individual chemical tests. Specifically, additive effects manifested with Cd and aniline at their IC10s, but changed to synergistic when the concentrations increased to IC20, and finally transitioned into antagonistic at IC30s and beyond. In addition, co-occurring aniline appeared to have retarded the cellular accumulation of Cd while increasing the enzymatic activities of superoxide dismutase and catalase relative to that in Cd-alone treatments. Finally, the bacterial community experienced distinct compositional changes under solo and combined toxicities with several genera exhibiting inconsistent behavior between treatments of single and composite toxicants. Findings from this study highlight the complexity of bacterial response to composite pollutions and point to the need for more comprehensive references in risk and toxicology assessment at multi-chemical contamination sites.

Host-microbiota affects the toxicity of Aflatoxin B1 in Caenorhabditis elegans

Aflatoxins are a group of potent fungal metabolites produced by Aspergillus and commonly contaminate groundnuts and cereal grains. Aflatoxin B₁ (AFB₁), the most potent mycotoxin, has been classified as Group 1 human carcinogen because it can be metabolically activated by the cytochrome P450 (CYP450) in the liver to form AFB₁-DNA adducts and induce gene mutations. Increasing evidence has shown the gut microbiota as a key mediator of AFB₁ toxicity through multiple interactive host-microbiota activities. To identify specific bacterial activity that modulates AFB₁ toxicity in Caenorhabditis (C.) elegans, we established a 3-way (microbe-worm-chemical) high-throughput screening system using C. elegans fed E. coli Keio collection on an integrated robotic platform, COPAS Biosort. We performed 2-step screenings using 3985 Keio mutants and identified 73 E. coli mutants that modulated C. elegans growth phenotype. Four genes (aceA, aceB, lpd, and pflB) involved in the pyruvate pathway were identified from the screening and confirmed to increase the sensitivity of all animals to AFB₁. Taking together, our results indicated that disturbances in bacterial pyruvate metabolism might have a significant impact on AFB₁ toxicity in the host.

Zinc homeostasis may reverse the synergistic neurotoxicity of heavy metal mixtures in Caenorhabditis elegans

Heavy metal mixtures can cause nerve damage. However, the combined effects of metal mixtures are extremely complex and rarely studied. Zinc (Zn) homeostasis plays an integral role in neural function, but the role of Zn homeostasis in the toxicity of metal mixtures is not well understood. Here, we investigated the combined effects of manganese (Mn), lead (Pb) and arsenic (As) on nerves and the effect of Zn homeostasis on metal toxicity. Caenorhabditis elegans (Maupas, 1900) were exposed to single and multiple metals for 8 days, their movement, behavior, neurons and metal concentration were detected to evaluate the combined effect of metal mixtures. After nematodes were co-treated with metal mixtures and Zn, the nerve function, Zn concentration and redox balance were detected to evaluate the effect of Zn homeostasis on metal toxicity. The results showed that Mn + Pb and Pb + As mixtures induced synergistic toxicity for nematode nerves, which damaged movement, behavior and neurons, and decreased Zn concentration. While Zn supplementation recovered Zn homeostasis and promoted redox balance on nematodes, and then improved the nerve function. Our study demonstrated the combined effects of metal mixtures and the neuroprotective effect of Zn homeostasis. Therefore, assessment of metal mixtures toxicity should consider their interaction and the impacts of essential metals homeostasis.

Effects of Single and Combined Ciprofloxacin and Lead Treatments on Zebrafish Behavior, Oxidative Stress, and Elements Content

Even though the toxic effects of antibiotics and heavy metals have been extensively studied in the last decades, their combined adverse impact on aquatic organisms is poorly understood. Therefore, the objective of this study was to assess the acute effects of a ciprofloxacin (Cipro) and lead (Pb) mixture on the 3D swimming behavior, acetylcholinesterase (AChE) activity, lipid peroxidation level (MDA-malondialdehyde), activity of some oxidative stress markers (SOD-superoxide dismutase and GPx-glutathione peroxidase), and the essential elements content (Cu-copper, Zn-zinc, Fe-iron, Ca-calcium, Mg-magnesium, Na-sodium and K-potassium) in the body of zebrafish (Danio rerio). For this purpose, zebrafish were exposed to environmentally relevant concentrations of Cipro, Pb, and a mixture for 96 h. The results revealed that acute exposure to Pb alone and in mixture with Cipro impaired zebrafish exploratory behavior by decreasing swimming activity and elevating freezing duration. Moreover, significant deficiencies of Ca, K, Mg, and Na contents, as well as an excess of Zn level, were observed in fish tissues after exposure to the binary mixture. Likewise, the combined treatment with Pb and Cipro inhibited the activity of AChE and increased the GPx activity and MDA level. The mixture produced more damage in all studied endpoints, while Cipro had no significant effect. The findings highlight that the simultaneous presence of antibiotics and heavy metals in the environment can pose a threat to the health of living organisms.

Acute Toxicity Evaluation of Phosphatidylcholine Nanoliposomes Containing Nisin in Caenorhabditis elegans

Liposomes are among the most studied nanostructures. They are effective carriers of active substances both in the clinical field, such as delivering genes and drugs, and in the food industry, such as promoting the controlled release of bioactive substances, including food preservatives. However, toxicological screenings must be performed to ensure the safety of nanoformulations. In this study, the nematode Caenorhabditis elegans was used as an alternative model to investigate the potential in vivo toxicity of nanoliposomes encapsulating the antimicrobial peptide nisin. The effects of liposomes containing nisin, control liposomes, and free nisin were evaluated through the survival rate, lethal dose (LD₅₀), nematode development rate, and oxidative stress status by performing mutant strain, TBARS, and ROS analyses. Due to its low toxicity, it was not possible to experimentally determine the LD₅₀ of liposomes. The survival rates of control liposomes and nisin-loaded liposomes were 94.3 and 73.6%, respectively. The LD₅₀ of free nisin was calculated as 0.239 mg mL^-1. Free nisin at a concentration of 0.2 mg mL^-1 significantly affected the development of C. elegans, which was 25% smaller than the control and liposome-treated samples. A significant increase in ROS levels was observed after exposure to the highest concentrations of liposomes and free nisin, coinciding with a significant increase in catalase levels. The treatments induced lipid peroxidation as evaluated by TBARS assay. Liposome encapsulation reduces the deleterious effect on C. elegans and can be considered a nontoxic delivery system for nisin.

The binary combined toxicity of lithium, lead, and manganese on the proliferation of murine neural stem cells using two different models

As persistent environmental pollutants, more than thirty metals impose a potential global threat to the environment and humans, which has raised scientific concerns. Although the toxic effects of metals had been extensively studied, there is a paucity of information on their mixture toxicity. In this study, we examined the individual and binary combined toxicity of three common metals such as lithium (Li), lead (Pb), and manganese (Mn) on the proliferation of murine neural stem cells (mNSCs), respectively. Li, Pb, and Mn reduced cell proliferation at the concentration of 5.00 mM, 2.50 μM, and 5.00 μM, respectively (all p < 0.050), in a dose-dependent manner of each metal solely on mNSCs with the cytotoxicity rank as Pb > Mn > Li. Furthermore, the interactions of metal mixtures on mNSCs were determined by using response-additivity and dose-additivity models. Pb + Mn mixtures showed a more than additive effect (synergistic) of toxicity in both two methods. In the dose-additivity method, Pb + Li and Li + Mn mixtures exhibited synergistic effects in the compound with a high ratio of Li (25.0% Pb/75.0% Li, 75.0% Li/25.0% Mn), whereas they are antagonistic in the lower or equal ratio of Li (such as 75.0% Pb/25.0% Li, 25.0% Li/75.0% Mn). Besides, the interactions of Li + Mn mixtures showed some discrepancies between different endpoints. In conclusion, our study highlights the complexity of the mixtures' interaction patterns and the possible neuroprotective effect of Li under certain conditions. In the future, more research on different levels of metal mixtures, especially Li metal, is necessary to evaluate their underlying interactions and contribute to establishing risk assessment systems.

A high-throughput microplate toxicity screening platform based on Caenorhabditis elegans

Caenorhabditis elegans (C. elegans), an established model organism, has been widely used in environmental toxicology research. However, most of the current toxicity testing methods based on worms are time-consuming. In this study we aimed to develop an automated and highly-integrated platform for high-throughput and in situ toxicity testing. Considering the superiority of C. elegans as a neurotoxicological model, this platform mainly evaluates general toxicology and neurotoxicology endpoints, which are usually induced by metals and pesticides, the major environmental contaminants. Microplates were used as a worm culturing system, which have good compatibility with any commercial microplate applicable instruments. We developed a microfluidic-based module for worm dispensing, and an image acquisition/analysis module for monitoring worms and detecting toxicity endpoints in bright filed. These were collectively incorporated with a commercial pipetting workstation for automated food/drug delivery and a high-content analysis system for fluorescence detection. The integrated platform achieved an efficient on-demand worm dispensing, long-term maintenance, regular monitoring and imaging, survival assay and behavioral analyses, and visualized gene reporter assay. Moreover, "Lab on Web" was achieved by connecting the platform to the web for remote operation, worm monitoring, and phenotype calculation. To demonstrate the ability of the platform for automated toxicity testing assays; worms were treated with cadmium and longevity, neurotoxicity, developmental toxicity and gst-4 expression were evaluated. We determined its feasibility and proposed the potential application in high-throughput toxicity screening for environmental risk assessment in the nearest future.

Reprint of: Elemental dysregulation in psychotic spectrum disorders: A review and research synthesis

Accumulating evidence from observational studies, genetic research, and animal models suggests a relationship between toxic and nutritive elements and psychotic spectrum disorders (PSD). This review systematically evaluates the current research evidence for two hypotheses: 1) that exposures to abnormal levels of toxic and nutritive elements early in life contributes to the subsequent development of PSD, and 2) that an imbalance of element levels is linked to psychotic illness and clinical severity. We focused on the extant literature on five elements, lead (Pb), copper (Cu), magnesium (Mg), manganese (Mn), and zinc (Zn), because of their previously documented associations with psychiatric problems and the availability of pertinent literature. The review identified 38 studies of which 11 measured Pb, 27 measured Cu, 16 measured Mg, 15 measured Mn, and 25 measured Zn concentrations in PSD patients and controls. A majority of research has been conducted on nutritive element imbalance, and findings are largely mixed. While it is biologically plausible that element dysregulation is an important modifiable risk factor for PSD, more research into exposure in early life is needed to better characterize this relationship.

Metal contamination and toxicity of soils and river sediments from the world's largest platinum mining area

Mining activities in the world's largest platinum mining area in South Africa have resulted in environmental contamination with Pt (e.g., the Hex River's vicinity). The present study compared a Pt mining area with a non-mining area along this river in terms of (1) metal concentrations in different grain size fractions from soils and aquatic sediments; (2) the toxicological potential of aquatic sediments based on the Consensus-Based Sediment Quality Guideline (CBSQG); and (3) the chronic toxicity of aqueous eluates from soils and sediments to Caenorhabditis elegans. Platinum concentrations were higher in the mining area than in the non-mining area. For most metals, the sediment silt and clay fraction contained the highest metal concentrations. Based on the CBSQG, most sampling sites exhibited a high toxicological potential, driven by Cr and Ni. Eluate toxicity testing revealed that C. elegans growth, fertility, and reproduction inhibition were not dependent on mining activities or the CBSQG predictions. Toxicity was instead likely due to Cd, Fe, Mn, Ni, Pt, and Pb. In conclusion, the investigated region is loaded with a high geogenic background resulting in high reproduction inhibition. The mining activities lead to additional environmental metal contamination (particularly Pt), contributing to environmental soil and sediment toxicity.

Application of Fluorescence Microscopy and Behavioral Assays to Demonstrating Neuronal Connectomes and Neurotransmitter Systems in C. elegans

The nematode Caenorhabditis elegans (C. elegans) is a prevailing model which is commonly utilized in a variety of biomedical research arenas, including neuroscience. Due to its transparency and simplicity, it is becoming a choice model organism for conducting imaging and behavioral assessment crucial to understanding the intricacies of the nervous system. Here, the methods required for neuronal characterization using fluorescent proteins and behavioral tasks are described. These are simplified protocols using fluorescent microscopy and behavioral assays to examine neuronal connections and associated neurotransmitter systems involved in normal physiology and aberrant pathology of the nervous system. Our aim is to make available to readers some streamlined and replicable procedures using C. elegans models as well as highlighting some of the limitations.

Elemental dysregulation in psychotic spectrum disorders: A review and research synthesis

Accumulating evidence from observational studies, genetic research, and animal models suggests a relationship between toxic and nutritive elements and psychotic spectrum disorders (PSD). This review systematically evaluates the current research evidence for two hypotheses: 1) that exposures to abnormal levels of toxic and nutritive elements early in life contributes to the subsequent development of PSD, and 2) that an imbalance of element levels is linked to psychotic illness and clinical severity. We focused on the extant literature on five elements, lead (Pb), copper (Cu), magnesium (Mg), manganese (Mn), and zinc (Zn), because of their previously documented associations with psychiatric problems and the availability of pertinent literature. The review identified 38 studies of which 11 measured Pb, 27 measured Cu, 16 measured Mg, 15 measured Mn, and 25 measured Zn concentrations in PSD patients and controls. A majority of research has been conducted on nutritive element imbalance, and findings are largely mixed. While it is biologically plausible that element dysregulation is an important modifiable risk factor for PSD, more research into exposure in early life is needed to better characterize this relationship.

Investigation into the trophic transfer and acute toxicity of phosphorus-based nano-agromaterials in Caenorhabditis elegans

Biogenic phosphorus (P) based - nanomaterials (NMs) are currently being explored as nanofertilizers. In this study, the acute toxic effects and trophic transfer of multiple types of P-based NMs were examined on soil-dwelling nematode, Caenorhabditis elegans. The study involved four variants of nanohydroxyapatites (nHAPs) synthesized either via a biogenic or a chemical route and another NM, nanophosphorus (nP), biosynthesized from bulk rock phosphate (RP). The pristine NMs differed in their physicochemical properties with each possessing different shapes (biogenic nHAP: platelet-shaped, ˜35 nm; biogenic nP, ˜5-10 nm: dots; chemically synthesized nHAPs: spherical, ˜33 nm, rod, ˜80 nm and needle-shaped, ˜64 nm). The toxic effects of NMs' in C. elegans were assessed using survival, hatching and reproductive cycle as the key endpoints in comparison to bulk controls, calcium phosphate and RP. The interactions and potential uptake of fluorescent-tagged nHAP to E. coli OP50 and C. elegans were investigated using confocal microscopy. The transformation of NMs within the nematode gut was also explored using dynamic light scattering and electron microscopy. C. elegans exposed to all of the variants of nHAP and the nP had 88-100% survival and 82-100% hatch rates and insignificant effects on brood size as observed at the tested environmentally relevant concentrations ranging from 5 to 100 μg.mL^-1. Confocal microscopy confirmed the interaction and binding of fluorescent-tagged nHAP with the surface of E. coli OP50 and their trophic transfer and internalization into C. elegans. Interestingly, there was only a small reduction in the hydrodynamic diameter of the nHAP after their uptake into C. elegans and the transformed NMs did not induce any additional toxicity as evident by healthy brood sizes after 72 h. This study provides key information about the environmental safety of agriculturally relevant P-based NMs on non-target species.

Heavy metal removal with magnetic coffee grain

The presence of heavy metals in environmental waters having an important place in the industrial waste is a major threat to viability. Heavy metals are transported to humans through the ecological cycle, damaging many tissues and organs. In recent years, agricultural and food waste can be used to remove heavy metals. At the present study, magnetically modified coffee grains which are alternative to conventional particle systems were prepared and heavy metal removal performances were investigated. The coffee grains used were magnetically modified by contact with water-based magnetic fluid. Magnetically modified coffee grains were characterized by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) surface area analysis and electron spin resonance (ESR). Adsorption studies are made with four different heavy metal ions, namely Cu(II), Pb(II), Cd(II) and Zn(II). Adsorption isotherms were determined and heavy metal removal performance of magnetic coffee grains were investigated from synthetic waste water.

Elucidating the influence of environmentally relevant toxic metal mixture on molecular mechanisms involved in the development of neurodegenerative diseases: In silico toxicogenomic data-mining

This in silico toxicogenomic analysis aims to: (i) testify the hypothesis about the influence of the environmentally relevant toxic metals (lead, methylmercury (organic form of mercury), cadmium and arsenic) on molecular mechanisms involved in amyotrophic lateral sclerosis (ALS), Parkinson's Disease (PD) and Alzheimer's disease (AD) development; and (ii) demonstrate the capability of in silico toxicogenomic data-mining for distinguishing the probable mechanisms of mixture-induced toxic effects. The Comparative Toxicogenomics Database (CTD; http://ctd. mdibl.org) and Cytoscape software were used as the main data-mining tools in this analysis. The results have shown that there were 7, 13 and 14 common genes for all the metals present in the mixture for each of the selected neurodegenerative disease (ND), respectively: ALS, PD and AD. Physical interactions (68.18%) were the most prominent interactions between the genes extracted for ALS, co-expression (60.85%) for PD and interactions predicted by the server (44.30%) for AD. SOD2 gene was noted as the mutual gene for all the selected ND. Oxidative stress, folate metabolism, vitamin B12, AGE-RAGE, apoptosis were noted as the key disrupted molecular pathways that contribute to the neurodegenerative disease's development. Gene ontology analysis revealed biological processes affected by the investigated mixture (glutathione metabolic process was listed as the most important for ALS, cellular response to toxic substance for PD, and neuron death for AD). Our results emphasize the role of oxidative stress, particularly SOD2, in neurodegeneration triggered by environmental toxic metal mixture and give a new insight into common molecular mechanisms involved in ALS, PD and AD pathology.

Phosphate: Coupling the functions of fertilization and passivation in phytoremediation of manganese-contaminated soil by Polygonum pubescens blume

Phosphate (P) fertilization is a commonly used agronomic practice. However, research on bioremediation is very limited. This study's principal objective was to evaluate the role of P in the growth and heavy metals (HMs) accumulation of Polygonum pubescens Blume cultured in Mn-contaminated soil. To this end, the effects of sodium dihydrogen phosphate (SDP) and single superphosphate (SSP) on the growth, Mn bioremediation efficiency, organ HMs, and physiological parameters related to antioxidant stress of P. pubescens were examined. The results showed that both SDP and SSP increased soil pH and available P but decreased available HMs. Phosphate significantly (P < 0.05) promoted P. pubescens height and biomass. Average height increased by 36.1% and 32.6% with SDP and SSP, respectively, with corresponding biomass increases of 71.8% and 135%. Phosphate significantly (P < 0.05) reduced Mn concentrations, especially in leaves, where the values decreased by >50.0% for DSP and SSP. Total Mn significantly (P < 0.05) decreased with DSP amendment but significantly (P < 0.05) increased by 38.5% with SSP (200 mg kg^-1) through an increase in biomass. Phosphate significantly (P < 0.05) decreased all organ HM concentrations and translocation, indicating that less HM stress occurred with P amendment. The changes in reactive oxygen species, antioxidants and non-antioxidant materials further supported these results. Pearson correlation analysis revealed negative relationships between soil available P and HMs, indicating a novel role of P in HM passivation. The uncommonly high Ca concentrations in leaves suggested that Ca plays a vital role in promoting growth and alleviating HM stress in P. pubescens, which warrants further study.

Detoxification mechanisms of nickel sulfate in nematode Caenorhabditis elegans

Nickel is the most prevailing metal allergen with the highest sensitization rate among the "TOP 25" contact allergens and can affect about 15% of the human population. It is an essential trace metal in plants, animals, and humans. However, the environmental levels of nickel are considerably higher than what is needed for human life. Exposure to high levels of nickel can lead to skin allergies, lung fibrosis, and carcinogenesis. Few existing studies have closely examined the toxicity of nickel, let alone investigated the effective detoxification pathways. Here, we developed a high-throughput screening platform to comprehensively evaluate the nickel toxicity in wild-type C. elegans and explore the underlying detoxification mechanisms in transgenic nematodes. We demonstrated that nickel exerted multiple toxic effects on growth, brood size, feeding, and locomotion in C. elegans. Of which, brood size is the most sensitive endpoint. Nickel was found to first bind to phytochelatin (PC) after entering the worms' body and this PC-Ni complex was further transported by the ABC transporter, CeHMT-1, into the coelomocytes for further detoxification. Our study also demonstrated that the high-throughput screening platform is a promising system for evaluation and investigation of the ecological risks of heavy metals.

Thallium Toxicity in Caenorhabditis elegans: Involvement of the SKN-1 Pathway and Protection by S-Allylcysteine

Monovalent thallium (Tl⁺) is a cation that can exert complex neurotoxic patterns in the brain by mechanisms that have yet to be completely characterized. To learn more about Tl⁺ toxicity, it is necessary to investigate its major effects in vivo and its ability to trigger specific signaling pathways (such as the antioxidant SKN-1 pathway) in different biological models. Caenorhabditis elegans (C. elegans) is a nematode constituting a simple in vivo biological model with a well-characterized nervous system, and high genetic homology to mammalian systems. In this study, both wild-type (N2) and skn-1 knockout (KO) mutant C. elegans strains subjected to acute and chronic exposures to Tl⁺ [2.5-35 μM] were evaluated for physiological stress (survival, longevity, and worm size), motor alterations (body bends), and biochemical changes (glutathione S-transferase regulation in a gst-4 fluorescence strain). While survival was affected by Tl⁺ in N2 and skn-1 KO (worms lacking the orthologue of mammalian Nrf2) strains in a similar manner, the longevity was more prominently decreased in the skn-1 KO strain compared with the wild-type strain. Moreover, chronic exposure led to a greater compromise in the longevity in both strains compared with acute exposure. Tl⁺ also induced motor alterations in both skn-1 KO and wild-type strains, as well as changes in worm size in wild-type worms. In addition, preconditioning nematodes with the well-known antioxidant S-allylcysteine (SAC) reversed the Tl⁺-induced decrease in survival in the N2 strain. GST fluorescent expression was also decreased by the metal in the nematode, and recovered by SAC. Our results describe and validate, for the first time, features of the toxic pattern induced by Tl⁺ in an in vivo biological model established with C. elegans, supporting an altered redox component in Tl⁺ toxicity, as previously described in mammal models. We demonstrate that the presence of the orthologous SKN-1 pathway is required for worms in evoking an efficient antioxidant defense. Therefore, the nematode represents an optimal model to reproduce mammalian Tl⁺ toxicity, where toxic mechanisms and novel therapeutic approaches of clinical value may be successfully pursued.

Distribution and Contamination Assessment of Soil Heavy Metals in the Jiulongjiang River Catchment, Southeast China

A total of 63 soil samples were collected from three soil profiles (yellow soil, red loam, red soil) from Jiulongjiang river catchment to investigate the distribution, controlling factors, and toxic risks of heavy metals, including Cr, Mn, Fe, Cu, Zn, Cd, Pb, and Ni. The results showed that Cr and Cd in soils were enriched. The relationships between heavy metals and soil properties were assessed by principal component analysis. The results indicated that soil organic matter (SOM) played a fundamental role in controlling Cd and Pb in yellow soil and red loam sites. The Cd was significantly correlated with Pb and Cu, and Cr, Zn, Ni, Fe displayed strong correlations with each other, however, no statistical correlation was found between Cd and Cr. The enrichment factor and geoaccumulation index analyses showed that the soils in the study area were contaminated by Cd. Potential ecological risk analyses indicated that Cd posed a considerable ecological risk in yellow soils, and posed a moderate ecological risk in red loams and red soils.

Citric Acid Enhances Plant Growth, Photosynthesis, and Phytoextraction of Lead by Alleviating the Oxidative Stress in Castor Beans

Lead (Pb) toxicity has a great impact in terms of toxicity towards living organisms as it severely affects crop growth, yield, and food security; thus, warranting appropriate measures for the remediation of Pb polluted soils. Phytoextraction of heavy metals (HMs) using tolerant plants along with organic chelators has gained global attention. Thus, this study examines the possible influence of citric acid (CA) on unveiling the potential phytoextraction of Pb by using castor beans. For this purpose, different levels of Pb (0, 300, 600 mg kg^-1 of soil) and CA (0, 2.5, and 5 mM) were supplied alone and in all possible combinations. The results indicate that elevated levels of Pb (especially 600 mg kg^-1 soil) induce oxidative stress, including hydrogen peroxide (H₂O₂) and malanodialdehyde (MDA) production in plants. The Pb stress reduces the photosynthetic traits (chlorophyll and gas exchange parameters) in the tissues of plants (leaves and roots), which ultimately lead to a reduction in growth as well as biomass. Enzyme activities such as guaiacol peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase are also linearly increased in a dose-dependent manner under Pb stress. The exogenous application of CA reduced the Pb toxicity in plants by improving photosynthesis and, ultimately, plant growth. The upsurge in antioxidants against oxidative stress shows the potential of CA-treated castor beans plants to counteract stress injuries by lowering H₂O₂ and MDA levels. From the results of this study, it can be concluded that CA treatments play a promising role in increasing the uptake of Pb and reducing its phytotoxicity. These outcomes recommend that CA application could be an effective approach for the phytoextraction of Pb from polluted soils by growing castor beans.