Non-essential Metals Research Articles

Assessment of occupational exposure to lead among workers engaged in a city bus garage in Addis Ababa, Ethiopia: a comparative cross-sectional study

BackgroundLead is one of the most nonessential toxic heavy metal agents found in automotive garages. The occupational exposure of garage workers to lead commonly poses acute and chronic health risks that can be prevented. In Ethiopia, there have been limited studies on lead exposure among garage workers, who overemphasize exposure to lead. This study aimed to assess occupational blood lead levels and associated factors in garage workers using a cross-sectional comparative design.MethodsA comparative cross-sectional study design was used to compare the occupational blood lead levels of 36 randomly selected garage workers and 34 office workers who were matched by age and sex. Blood specimens were collected by trained medical laboratory experts. The collected blood samples were tested in a certified laboratory using a microwave plasma atomic emission spectrometry (MP-AES) device at a wavelength of 405.78 nm. Excel and SPSS Version 26 were used for data management and analysis, respectively.ResultsThe mean (SD) age of the exposed group was 39.0 (7.5) years, whereas the mean age of the unexposed group was 38.0 (6.1) years. The occupational mean (SD) blood-lead-level in the exposed groups was 29.7 (12.2) µg/dl, compared to 14.8 (9.9) µg/dl among the unexposed groups. The mean blood-lead level among the exposed workers was significantly different from that among the unexposed workers (P < 0.01). Of all the study participants, only 22.2% of the exposed groups had blood lead levels higher than the World Health Organization’s recommended limit of 40 µg/dl. The main significant predictors of occupational blood-lead-level exposure among workers were extra working hours, service years, and having a previous (prior) employment history in a garage. The occupations of the two groups did not significantly differ in terms of blood-lead levels (p > 0.05).ConclusionsThe BLL of the Garage workers was significantly greater than that of the Non-Garage workers. Hence, it is advised that garage management should encourage workers to use exposure prevention methods, such as washing their hands before eating and taking showers after the completion of work, by providing regular occupational safety training.

Interaction between depression and non-essential heavy metals (Cd, Pb, and Hg) on metabolic diseases

ObjectivesMetal exposure and depression have each been associated with adverse metabolic diseases, but no study has examined the potential interaction between them. We examined the interaction of depression on the association between metals and metabolic diseases among adults. Study designThe interaction of depression in the relationship between metal and metabolic disease in adults was investigated using NHANES, a cross-sectional survey design. MethodsBy employing data from the NHANES database spanning the years 2007–2018, regression models were employed to investigate the independent impacts of heavy metals (cadmium, lead, and mercury) and depression on metabolic diseases (type 2 diabetes, hypertension, hyperlipidemia, metabolic syndrome). Subsequently, the association between metals and metabolic diseases was explored stratified by depression, and the interaction between heavy metals and depression was explored. Because of the complex NHANES design, statistical evaluations were adjusted through weighting to represent the populace of the United States. ResultsWe found log transformed-urinary lead was significantly associated with type 2 diabetes (OR: 2.33; 95 % CI: 1.23, 4.41) in adults with depression. Log transformed-urinary lead was not associated with type 2 diabetes (OR: 0.84; 95 % CI: 0.56, 1.27) in adults without depression. The interaction between Pb and depression in type 2 diabetes was significant (P for interaction = 0.033). Log transformed-urinary lead * depression was significantly associated with type 2 diabetes (OR: 1.82; 95 % CI: 1.01, 3.34) in adults. There was no significant interaction between cadmium and mercury exposure and depression in patients with type 2 diabetes, hypertension, hyperlipidemia, and metabolic syndrome (P for interaction > 0.05). ConclusionsThe presence of depression positively modified the adverse associations between urinary lead and type 2 diabetes.

Determination of Heavy Metal Contents in some Medicinal Plants from The Region of Oran from Algeria

Background: Some heavy metals found in our environment are toxic; once absorbed by plants, they build up in tissues and are phased out. Other heavy metals are trace elements needed for human health, but they can be toxic in excess concentrations. Objective: The purpose of this study is both to confirm the necessary metals' recognized medicinal virtues and to raise awareness of the presence of harmful non-essential metals that could harm humans and the environment. Methods: This study depicts a profile of existence of heavy metals (Zn, Cu, Cd, Pb, Fe) in some important herbal plants used in some parts of the country as a food condiment like (Moringa oleifera, Artemesia campestis, Nigella sativa, Asparagus stipularis, Sesamum indicum, Ruta montana, Rhamnus alaternus, Pistacia lentiscus using atomic absorption spectrophotometer. Results: The heavy metals in these medicinal plants were in the range of 0.38-0.56ppm of Zn, 0.00- 0.69 ppm of Cu, 0.13-0.16 ppm of Cd, 0.26-0.52 ppm of Pb, 1.10-8.89 ppm of Fe. Of the eight medicinal plants/products examined, the prescribed limits were respected. For each plant, a test sample of 2 grams of powder is mineralized. Each mineral is analyzed by injection. For each element, a calibration curve is generated. Assay with atomic absorption devices (lead, copper, cadmium, nickel, manganese) is carried out. The results are expressed in mg/L for different species. The highest value is lead. Copper content is present in various extracts and is considered a good source. Conclusion: The obtained results are promising for human health. The zinc contained in Moringa is very valuable. The presence of iron in the species Rhamnus alaternus confirms its use in traditional medicine as an anti-anemic.

Cd-induced cytotoxicity and its HO-1 and ROS quenching enzyme-mediated regulation in 2–3 leaf stage seedlings of Sorghum bicolor: An important millet crop of the arid & semi-arid regions

Cadmium is a non-essential trace metal element with no known biological function. Cd is toxic to both plants and human beings; hence, it is of prime concern to the scientific community. The objective of this research is to find out the effect of heme oxygenase 1 on Cd toxicity in Sorghum bicolor seedlings. Hydroponically adapted seedlings were treated to various concentrations of Cd within the range of 10 to 200 μM. Seedlings were harvested after 120 h of Cd stress. The cellular homeostasis and metal tolerance mechanisms were conducted to evaluate growth parameters, stress parameters (MDA and H2O2 content), non-enzymatic and enzymatic parameters (CAT, APX and GPX) including HO 1. The results showed that HO 1 activity was measured to be highest in leaves at 150 μM CdCl2, which was 29.61 %.The HO 1 activity was correlated with the MDA content and antioxidant enzymes activity at this Cd concentration. The highest activity of HO 1 was revealed through the decrease of GPX and CAT activities. Consequently, HO 1 works within a cohort that helps the development of the plant's defense mechanisms by scavenging ROS, which is confirmed by the time-dependent study. Accordingly, our research highlighted that HO 1 might increase the efficiency of stress tolerance by enhancing antioxidant defence mechanisms against Cd toxicity in S. bicolor.

Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy.

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg−1 dw) and REEs (447.3 ± 52.8 ng g−1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg−1 dw) and high-risk (9.14 mg kg−1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g−1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg−1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

Potential availability of metals in anaerobic mono- and co-digestion of pig manure and maize

This study aims to analyse the potential availability of essential metals including as Co, Fe, Ni, Zn, Mn, and Cu and non-essential metals such as Pb, Cr, and Cd within anaerobic mono- and co-digestion of pig manure and maize. The metals partitioning was determined using the Modified BCR (European Community Bureau of Reference) sequential extraction at defined intervals over a 45-days period, correlating changes in metals speciation with key digestion variables. The findings revealed that Cr, Cu, Fe, and Pb were predominantly associated with the oxidisable fraction, while Zn, Mn, and Cd were potentially available in both processes. Notably, NH4+-N and the VFAs, except propionic acid, correlated significantly with the available fractions of Co, Mn, Ni, Zn, Cr, and Pb during mono-digestion of pig manure. The wider pH range and the chemical properties of the feedstock in co-digestion resulted in varied correlations between the metals availability and the digestion variables.

Effect of Coffea canephora Bean Extract on Lead Acetate-Induced Rats

Lead (Pb) is a non-essential heavy metal that is toxic and has no known uses. Most cases of poisoning in livestock are caused by lead poisoning. This study aims to determine the effect of Coffea canephora bean extract as an antioxidant on the heart histopathological features of white rats (Rattus norvegicus) induced by lead acetate. This study used 25 male Wistar rats aged between eight and ten weeks and weighing between 200 and 250 grams. The rats were divided into five treatment groups, namely negative control (C-), positive control (C+), treatment one (T1), treatment two (T2), and treatment three (T3). The results suggested that the administration of 200 mg/kg BW, 400 mg/kg BW, or 800 mg/kg BW of Coffea canephora bean extract was not effective in improving the heart histopathological features, including cell degeneration, hemorrhage, and necrosis, of rats induced with lead acetate at a dose of 2 mg/kg BW.

Nitric oxide alleviates programmed cell death induced by cadmium in Solanum lycopersicum seedlings through protein S-nitrosylation

Cadmium (Cd), as a non-essential and toxic heavy metal in plants, has deleterious effects on plant physiological and biochemical processes. Nitric oxide (NO) is one of the most important signaling molecules for plants to response diverse stresses. Here, we found that Cd-induced programmed cell death (PCD) was accompanied by NO bursts, which exacerbated cell death when NO was removed and vice versa. Proteomic analysis of S-nitrosylated proteins showed that the differential proteins in Cd-induced PCD and in NO-alleviated PCD mainly exist together in carbohydrate metabolism and amino acid metabolism, while some of the differential proteins exist alone in metabolism of cofactors and vitamins and lipid metabolism. Meanwhile, S-nitrosylation of proteins in porphyrin and chlorophyll metabolism and starch and sucrose metabolism could explain the leaf chlorosis induced by PCD. Moreover, protein transport protein SEC23, ubiquitinyl hydrolase 1 and pathogenesis-related protein 1 were identified to be S-nitrosylated in vivo, and their expressions were increased in Cd-induced PCD while decreased in NO treatment. Similar results were obtained in tomato seedlings with higher S-nitrosylation. Taken together, our results indicate that NO might be involved in the regulation of Cd-induced PCD through protein S-nitrosylation, especially proteins involved in PCD response.

Metal mixture exposures and serum lipid levels in childhood: the Rhea mother-child cohort in Greece.

Growing evidence suggests that cardiovascular disease develops over the lifetime, often beginning in childhood. Metal exposures have been associated with cardiovascular disease and important risk factors, including dyslipidemia, but prior studies have largely focused on adult populations and single metal exposures. To investigate the individual and joint impacts of multiple metal exposures on lipid levels during childhood. This cross-sectional study included 291 4-year-old children from the Rhea Cohort Study in Heraklion, Greece. Seven metals (manganese, cobalt, selenium, molybdenum, cadmium, mercury, and lead) were measured in whole blood using inductively coupled plasma mass spectrometry. Serum lipid levels included total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol. To determine the joint and individual impacts of child metal exposures (log2-transformed) on lipid levels, Bayesian kernel machine regression (BKMR) was employed as the primary multi-pollutant approach. Potential effect modification by child sex and childhood environmental tobacco smoke exposure was also evaluated. BKMR identified a positive association between the metal mixture and both total and LDL cholesterol. Of the seven metals examined, selenium (median 90.6 [IQR = 83.6, 96.5] µg/L) was assigned the highest posterior inclusion probability for both total and LDL cholesterol. A difference in LDL cholesterol of 8.22 mg/dL (95% CI = 1.85, 14.59) was observed when blood selenium was set to its 75th versus 25th percentile, holding all other metals at their median values. In stratified analyses, the positive association between selenium and LDL cholesterol was only observed among boys or among children exposed to environmental tobacco smoke during childhood. Growing evidence indicates that cardiovascular events in adulthood are the consequence of the lifelong atherosclerotic process that begins in childhood. Therefore, public health interventions targeting childhood cardiovascular risk factors may have a particularly profound impact on reducing the burden of cardiovascular disease. Although growing evidence supports that both essential and nonessential metals contribute to cardiovascular disease and risk factors, such as dyslipidemia, prior studies have mainly focused on single metal exposures in adult populations. To address this research gap, the current study investigated the joint impacts of multiple metal exposures on lipid concentrations in early childhood.

Toxicity of Cadmium (Cd) on Artemia salina

Cd is a non-essential metal and a widespread micropollutant that has physiological effects on aquatic organisms. Cd heavy metal poisoning can be acutely caused by contamination at high doses, while chronic poisoning is generally caused by low levels of contamination and long exposure time. This research was conducted in June 2022 at the Marine Chemistry Laboratory Faculty of Fisheries and Marine, Universitas Riau, which aims to determine the value of LC50 (Lethal Concentration) for 24 hours after being given a toxicant in the form of Cd and to determine the level of Cd toxicity in A. salina. The method used in this research is the experimental method with the experimental unit A. salina. The LC50 of Cd on A. salina revealed 11.7109 mg/L. This concentration is capable of causing the death of 50% of the test animals. Furthermore, the water quality in the acute toxicity test, P0 (control), was classified as good to support the life of A. salina, while at P1 (3.13 mg/L) - P5 (50 mg/L), it was classified as polluted.

Detection of Essential and Non-Essential Metals in Dorsal Muscles and Skin of Bulte Tuna the Local Caught from Misurata Coast

Detection of Essential and Non-Essential Metals in Dorsal Muscles and Skin of Bulte Tuna the Local Caught from Misurata Coast

A metallothionein from disk abalone (Haliotis discus discus): Insights into its functional roles in immune response, metal tolerance, and oxidative stress

Metallothioneins (MTs) are cysteine-rich metal-binding proteins whose expression is induced by exposure to essential and non-essential metals, making them potential biological markers for assessing metal pollution in various biomonitoring programs. However, the functional properties of these proteins are yet to be comprehensively characterized in most marine invertebrates. In this study, we identified and characterized an MT homolog from the disk abalone (Haliotis discus discus), referred to as disk abalone MT (AbMT). AbMT exhibited the same primary structural features as MTs from other mollusks containing two β-domains (β2β1-form). AbMT protein demonstrated metal-binding and detoxification abilities against Zn, Cu, and Cd, as evidenced by Escherichia coli growth kinetics, metal tolerance analysis, and UV absorption spectrum. Transcriptional analysis revealed that AbMT was ubiquitously expressed in all analyzed tissues and upregulated in gill tissue following challenge with Vibrio parahaemolyticus, Listeria monocytogenes, and viral hemorrhagic septicemia virus (VHSV). Additionally, overexpression of AbMT suppressed LPS-induced NO production in RAW264.7 macrophages, protected cells against H2O2-induced oxidative stress, and promoted macrophage polarization toward the M1 phase. Conclusively, these findings suggest an important role for AbMT in environmental stress protection and immune regulation in disk abalone.

Lead-induced liver fibrosis and inflammation in mice by the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways: the role of Isochlorogenic acid a.

Lead (Pb) is a nonessential heavy metal, which can cause many health problems. Isochlorogenic acid A (ICAA), a phenolic acid present in tea, fruits, vegetables, coffee, plant-based food products, and various medicinal plants, exerts multiple effects, including anti-oxidant, antiviral, anti-inflammatory and antifibrotic functions. Thus, the purpose of our study was to determine if ICAA could prevent Pb-induced hepatotoxicity in ICR mice. An evaluation was performed on oxidative stress, inflammation and fibrosis, and related signaling. The results indicate that ICAA attenuates Pb-induced abnormal liver function. ICAA reduced liver fibrosis, inflammation and oxidative stress caused by Pb. ICAA abated Pb-induced fibrosis and decreased inflammatory cytokines interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α). ICAA abrogated reductions in activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Masson staining revealed that ICAA reduced collagen fiber deposition in Pb-induced fibrotic livers. Western blot and immunohistochemistry analyses showed ICAA increased phosphorylated AMP-activated protein kinase (p-AMPK) expression. ICAA also reduced the expression of collagen I, α-smooth muscle actin (α-SMA), phosphorylated extracellular signal-regulated kinase (p-ERK), phosphorylated c-jun N-terminal kinase (p-JNK), p-p38, phosphorylated signal transducer and phosphorylated activator of transcription 3 (p-STAT3), transforming growth factor β1 (TGF-β1), and p-Smad2/3 in livers of mice. Overall, ICAA ameliorates Pb-induced hepatitis and fibrosis by inhibiting the AMPK/MAPKs/NF-κB and STAT3/TGF-β1/Smad2/3 pathways.

Comparative assessment of levels and dietary intake of mineral nutrients and toxic metals in different varieties of teff from Hidabu Abote, Ethiopia

Ethiopia is the largest teff (Eragrostis teff Zucc) producer in the world. This research was intended to determine the levels of mineral nutrients and non-essential metals in the teff samples. After optimization, the samples were wet-digested using reagents (5 mL HNO3 and 1 mL HClO4), at a temperature of 230 °C for 2:30 h. Inductively coupled plasma optical emission spectrometry was used for the analysis of mineral nutrients and toxic metals in the teff samples. Under the optimum procedure, the coefficients of determination (R2) ranged between 0.9980 and 0.9999. The limits of detections (LODs) and limits of quantifications (LOQs) were in the range of 0.036–14.49 mg/kg and 0.111–43.93 mg/kg, respectively. The recovery ranged from 80.72 % to 107.79 %. The overall mean concentration in the three types of teff samples determined (mg/kg) was in the range of P (3890–4853), K (3040–3784), Ca (1906–1959), Mg (1402–1698), Fe (128–305), Mn (64–127.8), Na (50–136.5), Zn (19.8–27.3), B (1.8–21.9), Cu (4.17–6.9), Ni (2.6–4.05), Hg (1.8–4.0), Pb (0.048–3.7), Cd (0.012–2.09), As (0.02–0.24), with% RSD ranging between 0.017 and 11.1 %. The results obtained revealed that teff grain is a good source of minerals and contains a significant amount of toxic elements like Cd, Hg, As, and Pb.

Analysis of Cadmium (Cd) Heavy Metal Levels in Groundwater around Lapindo Mudflow, Sidoarjo Regency

Background &amp; Objective: Metal pollution in Lapindo mudflow is one of the events that cause pollution because the content in the mud contains a variety of heavy metals, one of which is cadmium (Cd). Cadmium is a heavy metal that has high toxicity and is included in non-essential heavy metals, so the presence of heavy metal cadmium (Cd) needs to be known for sure because too high levels can harm health and the surrounding environment. The purpose of this study is to determine the presence of cadmium (Cd) heavy metal levels in groundwater around Lapindo Mudflow, Sidoarjo Regency. Method: This study uses descriptive type and design. The sampling technique used purposive sampling by taking 4 points and conducting a duplo examination so that the total number of samples was 8 samples. Results: The results showed that out of 8 samples, all samples still met the requirements according to SNI with a percentage of 100%. Conclusion: It can be concluded that the results of the study with an average of 0.5075 × 10-4 mg/L still meet the requirements in accordance with the Indonesian National Standard (SNI) which is 0.5 - 10.0 mg/L or 0.0005 - 0.001 mg/L.

The Impact of Thallium Exposure in Public Health and Molecular Toxicology: A Comprehensive Review.

This review offers a synthesis of the current understanding of the impact of low-dose thallium (Tl) on public health, specifically emphasizing its diverse effects on various populations and organs. The article integrates insights into the cytotoxic effects, genotoxic potential, and molecular mechanisms of thallium in mammalian cells. Thallium, a non-essential heavy metal present in up to 89 different minerals, has garnered attention due to its adverse effects on human health. As technology and metallurgical industries advance, various forms of thallium, including dust, vapor, and wastewater, can contaminate the environment, extending to the surrounding air, water sources, and soil. Moreover, the metal has been identified in beverages, tobacco, and vegetables, highlighting its pervasive presence in a wide array of food sources. Epidemiological findings underscore associations between thallium exposure and critical health aspects such as kidney function, pregnancy outcomes, smoking-related implications, and potential links to autism spectrum disorder. Thallium primarily exerts cellular toxicity on various tissues through mitochondria-mediated oxidative stress and endoplasmic reticulum stress. This synthesis aims to shed light on the intricate web of thallium exposure and its potential implications for public health, emphasizing the need for vigilant consideration of its risks.

Nutrients and non-essential metals in darkibor kale grown at urban and rural farms: A pilot study.

Kale is a nutrient-dense leafy vegetable associated with wide-ranging health benefits. It is tolerant of drought and temperature fluctuations, and could thus serve an increasingly important role in providing a safe and nutritious food supply during the climate crisis, while kale's ease of cultivation and ability to be grown in a wide range of soils make it a good fit for urban agriculture. In this pilot study we explored potential differences between kale grown at urban versus rural farms. We planted kale seedlings (Darkibor variety) at three urban and four rural farms in and around Baltimore City, Maryland, instructed farmers to cultivate them using their usual growing practices, harvested the kale from fields and points of distribution, and analyzed it for concentrations of carotenoids, vitamins C and K1, ten nutritional elements, and eight non-essential metals. Although sample sizes for some analyses were in some cases too small to produce statistically significant results, we identified potentially meaningful differences in concentrations of several components between urban and rural kale samples. Compared to urban samples, mean concentrations of carotenoids and vitamins were 22-38% higher in rural field samples. By contrast, mean concentrations for eight nutritional elements were higher in urban field samples by as much as 413% for iron. Compared to rural field samples, mean concentrations of nine non-essential metals were higher in urban samples, although lead and cadmium concentrations for all samples were below public health guidelines. Some urban-rural differences were more pronounced than those identified in prior research. For six elements, variance within urban and rural farms was greater than variance between urban and rural farms, suggesting urbanicity may not be the primary driver of some observed differences. For some nutrients, mean concentrations were higher than upper ranges reported in prior estimates, suggesting kale may have the potential to be more nutrient-dense than previously estimated. The nutritive and metals composition of this important crop, and the factors that influence it, merit continued investigation given its growing popularity.

Synthesis and Biological Activities of Some Metal Complexes of Peptides: A Review.

Peptides, both natural and synthetic, are well suited for a wide range of purposes and offer versatile applications in different fields such as biocatalysts, injectable hydrogels, tumor treatment, and drug delivery. The research of the better part of the cited papers was conducted using various database platforms such as MetalPDB. The rising prominence of therapeutic peptides encompasses anticancer, antiviral, antimicrobial, and anti-neurodegenerative properties. The metals Na, K, Mg, Ca, Fe, Mn, Co, Cu, Zn, and Mo are ten of the twenty elements that are considered essential for life. Crucial for understanding the biological role of metals is the exploration of metal-bound proteins and peptides. Aside from essential metals, there are other non-essential metals that also interact biologically, exhibiting either therapeutic or toxic effects. Irregularities in metal binding contribute to diseases like Alzheimer's, neurodegenerative disorders, Wilson's, and Menkes disease. Certain metal complexes have potential applications as radiopharmaceuticals. The examination of these complexes was achieved by preforming UV-Vis, IR, EPR, NMR spectroscopy, and X-ray analysis. This summary, although unable to cover all of the studies in the field, offers a review of the ongoing experimentation and is a basis for new ideas, as well as strategies to explore and gain knowledge from the extensive realm of peptide-chelated metals and biotechnologies.

Fluorescent Protein-Based Sensors for Detecting Essential Metal Ions across the Tree of Life.

Genetically encoded fluorescent metal ion sensors are powerful tools for elucidating metal dynamics in living systems. Over the last 25 years since the first examples of genetically encoded fluorescent protein-based calcium indicators, this toolbox of probes has expanded to include other essential and non-essential metal ions. Collectively, these tools have illuminated fundamental aspects of metal homeostasis and trafficking that are crucial to fields ranging from neurobiology to human nutrition. Despite these advances, much of the application of metal ion sensors remains limited to mammalian cells and tissues and a limited number of essential metals. Applications beyond mammalian systems and in vivo applications in living organisms have primarily used genetically encoded calcium ion sensors. The aim of this Perspective is to provide, with the support of historical and recent literature, an updated and critical view of the design and use of fluorescent protein-based sensors for detecting essential metal ions in various organisms. We highlight the historical progress and achievements with calcium sensors and discuss more recent advances and opportunities for the detection of other essential metal ions. We also discuss outstanding challenges in the field and directions for future studies, including detecting a wider variety of metal ions, developing and implementing a broader spectral range of sensors for multiplexing experiments, and applying sensors to a wider range of single- and multi-species biological systems.

Chronic effect of copper on biology, immunity, and biochemical assessment of Helicoverpa armigera (Lepidoptera; Noctuidae) in laboratory bioassays.

Although copper is an essential element for any organism's well-being, it becomes toxic if present in excess. In the present study, copper was provisioned at 25, 50, and 75 mg/kg in an artificial diet and fed to juvenile larvae of cotton bollworm, Helicoverpa armigera (Lepidoptera; Noctuidae), for 4 generations. The results of this investigation exhibited shortening of larval life in the first 2 generations, but extended duration was observed in third and fourth generations compared to controls, and dietary copper caused reduced total hemocyte counts in all treatments. The number of immunocytes (i.e., granulocytes and plasmatocytes) were also significantly reduced. The changes in activities of certain important enzymes, including catalase, superoxide dismutase, and peroxidases, were seen. Furthermore, after treatment, an increase in the activity of 2 detoxifying enzymes, glutathione s-transferase and acetylcholinesterase, was observed. It is clear that metallothioneins are important in maintaining essential and nonessential metal ion homeostasis. While copper is typically regarded as an important essential metal in an organism's life, excessive amounts can have deteriorating effects. This heavy metal is being used as a nano-based pesticide. Therefore, the present investigation aims to determine the fate of Cu in insects receiving them in new formulations.