scholarly journals Lead Toxicity in Cereals: Mechanistic Insight Into Toxicity, Mode of Action, and Management

2021 ◽  
Vol 11 ◽  
Author(s):  
Muhammad Aslam ◽  
Ayesha Aslam ◽  
Muhammad Sheraz ◽  
Basharat Ali ◽  
Zaid Ulhassan ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Metal Tolerance ◽  
Mineral Metabolism ◽  
Management Strategies ◽  
Lead Toxicity ◽  
Stability Index ◽  
Natural Resistance ◽  
Oxygen Evolving Complex ◽  
Pb Toxicity ◽  
Cellular Modifications

Cereals are the major contributors to global food supply, accounting for more than half of the total human calorie requirements. Sustainable availability of quality cereal grains is an important step to address the high-priority issue of food security. High concentrations of heavy metals specifically lead (Pb) in the soil negatively affect biochemical and physiological processes regulating grain quality in cereals. The dietary intake of Pb more than desirable quantity via food chain is a major concern for humans, as it can predispose individuals to chronic health issues. In plant systems, high Pb concentrations can disrupt several key metabolic processes such as electron transport chain, cellular organelles integrity, membrane stability index, PSII connectivity, mineral metabolism, oxygen-evolving complex, and enzymatic activity. Plant growth-promoting rhizobacteria (PGPR) has been recommended as an inexpensive strategy for remediating Pb-contaminated soils. A diverse group of Ascomycetes fungi, i.e., dark septate endophytes is successfully used for this purpose. A symbiotic relationship between endophytes and host cereal induces Pb tolerance by immobilizing Pb ions. Molecular and cellular modifications in plants under Pb-stressed environments are explained by transcription factor families such as bZIP, ERF, and GARP as a regulator. The role of metal tolerance protein (MTP), natural resistance-associated macrophage protein (NRAMP), and heavy metal ATPase in decreasing Pb toxicity is well known. In the present review, we provided the contemporary synthesis of existing data regarding the effects of Pb toxicity on morpho-physiological and biochemical responses of major cereal crops. We also highlighted the mechanism/s of Pb uptake and translocation in plants, critically discussed the possible management strategies and way forward to overcome the menace of Pb toxicity in cereals.

scholarly journals Chemical Properties of Heavy Metal-Contaminated Soils from a Korean Military Shooting Range: Evaluation of Pb Sources Using Pb Isotope Ratios

2021 ◽  
Vol 11 (15) ◽  
pp. 7099
Author(s):  
Inkyeong Moon ◽  
Honghyun Kim ◽  
Sangjo Jeong ◽  
Hyungjin Choi ◽  
Jungtae Park ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Management Strategies ◽  
Chemical Properties ◽  
Heavy Metal Concentration ◽  
Soil Samples ◽  
Shooting Range ◽  
Geochemical Properties ◽  
Mineral Phases

In this study, the geochemical properties of heavy metal-contaminated soils from a Korean military shooting range were analyzed. The chemical behavior of heavy metals was determined by analyzing the soil pH, heavy metal concentration, mineral composition, and Pb isotopes. In total, 24 soil samples were collected from a Korean military shooting range. The soil samples consist of quartz, albite, microcline, muscovite/illite, kaolinite, chlorite, and calcite. Lead minerals, such as hydrocerussite and anglesite, which are indicative of a transformation into secondary mineral phases, were not observed. All soils were strongly contaminated with Pb with minor concentrations of Cu, Ni, Cd, and Zn. Arsenic was rarely detected. The obtained results are indicated that the soils from the shooting range are contaminated with heavy metals and have evidences of different degree of anthropogenic Pb sources. This study is crucial for the evaluation of heavy metal-contaminated soils in shooting ranges and their environmental effect as well as for the establishment of management strategies for the mitigation of environmental risks.

scholarly journals Transport, functions, and interaction of calcium and manganese in plant organellar compartments

2021 ◽  
Author(s):  
Jie He ◽  
Nico Rössner ◽  
Minh T T Hoang ◽  
Santiago Alejandro ◽  
Edgar Peiter
Keyword(s):  
Molecular Mechanisms ◽  
Metal Tolerance ◽  
Essential Elements ◽  
Natural Resistance ◽  
Ionic Radii ◽  
Bivalent Cation ◽  
Cyclic Nucleotide Gated Channels ◽  
Complex Processes ◽  
Open Questions ◽  
Golgi Network

Abstract Calcium (Ca2+) and manganese (Mn2+) are essential elements for plants and have similar ionic radii and binding coordination. They are assigned specific functions within organelles, but share many transport mechanisms to cross organellar membranes. Despite their points of interaction, those elements are usually investigated and reviewed separately. This review takes them out of this isolation. It highlights our current mechanistic understanding and points to open questions of their functions, their transport, and their interplay in the endoplasmic reticulum (ER), vesicular compartments [Golgi apparatus, trans-Golgi Network (TGN), prevacuolar compartment (PVC)], vacuoles, chloroplasts, mitochondria, and peroxisomes. Complex processes demanding these cations, such as Mn2+-dependent glycosylation or systemic Ca2+ signaling, are covered in some detail if they have not been reviewed recently or if recent findings add to current models. The function of Ca2+ as signaling agent released from organelles into the cytosol and within the organelles themselves is a recurrent theme of this review, again keeping the interference by Mn2+ in mind. The involvement of organellar channels [e.g., Glutamate-Receptor-Likes (GLRs), Cyclic-Nucleotide-Gated Channels (CNGCs), Mitochondrial Conductivity Units (MCUs), Two-Pore Channel1 (TPC1)], transporters [e.g., Natural-Resistance-Associated Macrophage Proteins (NRAMPs), Calcium Exchangers (CAXs), Metal-Tolerance Proteins (MTPs), Bivalent-Cation Transporters (BICATs)] and pumps [Autoinhibited Ca2+-ATPases (ACAs), ER Ca2+-ATPases (ECAs)] in the import and export of organellar Ca2+ and Mn2+ is scrutinized, whereby current controversial issues are pointed out. Mechanisms in animals and yeast are taken into account where they may provide a blueprint for processes in plants, in particular with respect to tunable molecular mechanisms of Ca2+-versus-Mn2+ selectivity.

scholarly journals Lead Toxicity: Health Hazards, Influence on Food Chain, and Sustainable Remediation Approaches

2020 ◽  
Vol 17 (7) ◽  
pp. 2179 ◽  
Author(s):  
Amit Kumar ◽  
Amit Kumar ◽  
Cabral-Pinto M.M.S. ◽  
Ashish K. Chaturvedi ◽  
Aftab A. Shabnam ◽  
...  
Keyword(s):  
Food Chain ◽  
Health Hazard ◽  
Relevant Literature ◽  
Lead Toxicity ◽  
Toxic Heavy Metals ◽  
Potential Health ◽  
Pb Toxicity ◽  
Potential Health Hazard ◽  
Key Issues ◽  
Safe Food

Lead (Pb) toxicity has been a subject of interest for environmental scientists due to its toxic effect on plants, animals, and humans. An increase in several Pb related industrial activities and use of Pb containing products such as agrochemicals, oil and paint, mining, etc. can lead to Pb contamination in the environment and thereby, can enter the food chain. Being one of the most toxic heavy metals, Pb ingestion via the food chain has proven to be a potential health hazard for plants and humans. The current review aims to summarize the research updates on Pb toxicity and its effects on plants, soil, and human health. Relevant literature from the past 20 years encompassing comprehensive details on Pb toxicity has been considered with key issues such as i) Pb bioavailability in soil, ii) Pb biomagnification, and iii) Pb- remediation, which has been addressed in detail through physical, chemical, and biological lenses. In the review, among different Pb-remediation approaches, we have highlighted certain advanced approaches such as microbial assisted phytoremediation which could possibly minimize the Pb load from the resources in a sustainable manner and would be a viable option to ensure a safe food production system.

Ecogenetics of lead toxicity and its influence on risk assessment

2019 ◽  
Vol 38 (9) ◽  
pp. 1031-1059 ◽  
Author(s):  
MS Mani ◽  
SP Kabekkodu ◽  
MB Joshi ◽  
HS Dsouza
Keyword(s):  
Risk Assessment ◽  
Mechanism Of Action ◽  
Age Groups ◽  
Public Health Problem ◽  
Lead Toxicity ◽  
Dependent Manner ◽  
Pb Toxicity ◽  
Interindividual Variations ◽  
Epigenetic Biomarkers ◽  
Pb Exposure

Lead (Pb) toxicity is a public health problem affecting millions worldwide. Advances in ‘omic’ technology have paved the way to toxico-genomics which is currently revolutionizing the understanding of interindividual variations in susceptibility to Pb toxicity and its functional consequences to exposure. Our objective was to identify, comprehensively analyze, and curate all the potential genetic and epigenetic biomarkers studied to date in relation to Pb toxicity and its association with diseases. We screened a volume of research articles that focused on Pb toxicity and its association with genetic and epigenetic signatures in the perspective of occupational and environmental Pb exposure. Due to wide variations in population size, ethnicity, age-groups, and source of exposure in different studies, researchers continue to be skeptical on the topic of the influence of genetic variations in Pb toxicity. However, surface knowledge of the underlying genetic factors will aid in elucidating the mechanism of action of Pb. Moreover, in recent years, the application of epigenetics in Pb toxicity has become a promising area in toxicology to understand the influence of epigenetic mechanisms such as DNA methylation, chromatin remodeling, and small RNAs for the regulation of genes in response to Pb exposure during early life. Growing evidences of ecogenetic understanding (both genetic and epigenetic processes) in a dose-dependent manner may help uncover the mechanism of action of Pb and in the identification of susceptible groups. Such studies will further help in refining uncertainty factors and in addressing risk assessment of Pb poisoning.

scholarly journals Modulating effect of EDTA and SDS on growth, biochemical parameters and antioxidant defense system of Dahlia variabilis grown under cadmium and lead-induced stress

2020 ◽  
Vol 48 (2) ◽  
pp. 906-923
Author(s):  
Yahya ALZAHRANI ◽  
Hesham F. ALHARBY ◽  
Khalid R. HAKEEM ◽  
Hameed ALSAMADANY
Keyword(s):  
Contaminated Soils ◽  
Metal Tolerance ◽  
Ethylenediaminetetraacetic Acid ◽  
Culture Media ◽  
Soluble Sugar ◽  
Sodium Dodecyl ◽  
H2o2 Production ◽  
Total Soluble Sugar ◽  
Inorganic Amendments ◽  
Dahlia Variabilis

The present study investigated the influence of inorganic amendments viz., SDS (sodium dodecyl sulphate) and ethylenediaminetetraacetic acid (EDTA) in enhancing metal tolerance in plants. Seedlings of an important ornamental plant, Dahlia variabilis Cav. were grown under cadmium (Cd) and lead (Pb) stress. 30-days old seedlings were transferred to pots containing sterilized sand and supplemented with Hoagland’s medium. After 15 days of transplanting, four treatments (0, 10, 25, and 100 mg kg-1) of Cd and four treatments of Pb (0, 100, 500 and 5000 mg kg-1) were used with or without application of 2.0 mM SDS and 2.5 mM EDTA, separately and in combination. Seedlings were further grown for 60 days in culture media. Results revealed that both Cd and Pb significantly reduced plant growth, pigment content, and relative water content. Antioxidant enzymes viz., superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) along with protein and total soluble sugar contents showed a declining trend with an increase in Cd and Pb concentrations applied. The Cd and Pb treatment enhanced the production rate of reactive oxygen species (ROS) as depicted by the increased malondialdehyde (MDA) and hydrogen peroxide (H2O2) production in leaf. Inorganic amendments viz., EDTA+SDS applied either alone or in combination significantly alleviated Cd and Pb-induced toxic effects. However, a combination of EDTA+SDS showed significant results than used separately. These results revealed that the application of inorganic amendments in combination can enhance the phytoextraction capacity of the species studied. However, the effects of various amendments vary with the nature of the inorganic compound. The study suggests that the application of EDTA and SDS could be a useful strategy for enhancing the phytoextraction capability of Dahlia variabilis to remove Cd and Pb from contaminated soils.

scholarly journals Determination of Natural Resistance Frequencies in Penicillium digitatum Using a New Air-Sampling Method and Characterization of Fludioxonil- and Pyrimethanil-Resistant Isolates

2010 ◽  
Vol 100 (8) ◽  
pp. 738-746 ◽  
Author(s):  
L. Kanetis ◽  
H. Förster ◽  
J. E. Adaskaveg
Keyword(s):  
Concentration Gradient ◽  
Fungicide Resistance ◽  
Sampling Method ◽  
Management Strategies ◽  
Air Sampling ◽  
Penicillium Digitatum ◽  
Natural Resistance ◽  
Fungicide Sensitivity ◽  
Laboratory Selection ◽  
Wide Range

Fungicide resistance was identified in natural populations of Penicillium digitatum, the causal agent of green mold of citrus, to two of three new postharvest fungicides before their commercial use. Using a new air-sampling method where large populations of the pathogen in citrus packinghouses were exposed to agar plates with a continuous, wide-range fungicide concentration gradient, isolates with reduced sensitivity to fludioxonil or pyrimethanil were obtained. Resistance frequencies to fludioxonil and pyrimethanil were calculated as 9.5 × 10–7 to 1.5 × 10–5 and 7.3 × 10–6 to 6.2 × 10–5, respectively. No isolates resistant to azoxystrobin were detected. Isolates with reduced sensitivity to fludioxonil or pyrimethanil were also obtained in laboratory selection studies, where high concentrations of conidial mixtures of isolates sensitive to the three fungicides were plated onto agar amended with each fungicide at 10 μg/ml. Isolates obtained from fludioxonil selection plates in laboratory and packinghouse experiments were placed into two categories based on mycelial growth: moderately resistant isolates had 50% effective concentration (EC50) values of 0.1 to 0.82 μg/ml and highly resistant isolates had EC50 values > 1.5 μg/ml. Isolates resistant to pyrimethanil all had EC50 values >8 μg/ml. Representative isolates of the two categories with reduced sensitivity to fludioxonil varied widely in their virulence and sporulation capacity as measured by the incidence of decay and degree of sporulation on inoculated fruit, respectively, whereas pyrimethanil-resistant isolates were mostly similar to the wild-type isolate. Fungicide sensitivity characteristics for isolates from fludioxonil and pyrimethanil selection plates remained stable after passages on nonamended agar, and disease could not be controlled after treatment with the respective fungicides. Types of fungicide resistance were visualized on thiabendazole- (TBZ) and imazalil-amended selection plates that were exposed in packinghouses where resistance to these fungicides was known to occur. The qualitative, single-site resistance to the benzimidazole TBZ was visualized by two distinct subpopulations in regard to fungicide sensitivity, whereas the quantitative, multi-site resistance to the demethylation inhibitor imazalil was apparent as a continuous density gradient of colonies along the fungicide concentration gradient. Types of resistance could not be assigned to fludioxonil or pyrimethanil because a limited number of resistant colonies was obtained on each plate. Thus, with this new method, we were able to estimate fungicide resistance frequencies as well as characterize and visualize types of resistance within populations of a fungal species. This information will be used to design resistance management strategies for previous and newly registered postharvest fungicides of citrus.

Metal tolerance in Agrostis scabra from the Sudbury, Ontario, area

1995 ◽  
Vol 73 (5) ◽  
pp. 766-775 ◽  
Author(s):  
Daniel J. Archambault ◽  
Keith Winterhalder
Keyword(s):  
Root Growth ◽  
Contaminated Soils ◽  
Metal Tolerance ◽  
Leaf Growth ◽  
Acid Soil ◽  
Hydroponic Experiment ◽  
Ecological Aspects ◽  
Bioassay Experiment ◽  
Tolerance Indices

Acid, metal-contaminated soils are frequently colonized by plant species that have evolved tolerance to metals. Agrostis scabra (tickle grass) grows at several such sites in the Sudbury area. To test whether these populations were tolerant to metals, three experiments were performed. A hydroponic root growth experiment, in which clonal ramets from contaminated and uncontaminated sites were grown in metal-amended nutrient solutions, showed that plants from the Sudbury area had greater tolerance indices than those from outside Sudbury. A seed-based hydroponic experiment, where seeds were germinated in metal solutions, showed that metal-tolerance indices calculated from root growth were mostly greater for populations from Sudbury but that leaf growth was not a good indicator of metal tolerance. A seed-based soil-bioassay experiment, in which seeds were germinated on soils covered with filter paper, showed that seeds from contaminated sites performed better on contaminated soil and a 50:50 soil mixture (contaminated–uncontaminated) than those from uncontaminated sites. Populations of A. scabra growing on contaminated soils in the Sudbury area therefore appear to have been selected for metal tolerance. Ecological aspects of metal tolerance and the possible role of A. scabra in the revegetation of the Sudbury area are discussed. Key words: Agrostis scabra, tolerance, metals, acid soil, contamination.

scholarly journals Evaluation of Metal Tolerance of Fungal Strains Isolated from Contaminated Mining Soil of Nanjing, China

Biology ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 469
Author(s):  
Fiza Liaquat ◽  
Muhammad Farooq Hussain Munis ◽  
Urooj Haroon ◽  
Samiah Arif ◽  
Saddam Saqib ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Metal Tolerance ◽  
Morphological Changes ◽  
Tolerance Index ◽  
Metal Analysis ◽  
Aspergillus Aculeatus ◽  
Yeast Strains ◽  
High Concentrations ◽  
Induced Tolerance ◽  
Aspergillus Sclerotiorum

Rapidly increasing industry has resulted in greater discharge of hazardous chemicals in the soil. In the current study, soil samples were collected from Nanjing mine (32°09′19.29″ N 118°56′57.04″ E) and subjected to heavy metal analysis and microbe isolation. A total of 460 fungi were isolated, and five of these were yeast strains. Most of the strains exhibited tolerance to one metal. Five multimetal tolerant strains were selected and identified as Aspergillus sclerotiorum, Aspergillus aculeatus, Komagataella phaffii, Trichoderma harzianum, and Aspergillus niger. Isolated strains were grown in high concentrations of cadmium (Cd), chromium (Cr) and lead (Pb), for induced-tolerance training. The tolerance index (TI) revealed the highest Cd tolerance of novel K. phaffii strain at 5500 ppm (TI: 0.2). K. phaffii also displayed resistance at 4000 ppm against Cr (TI: 0.32) and Pb (TI: 0.32). In contrast, tolerance training for A. niger was not that successful. K. phaffii also displayed the highest bioaccumulation capacity for Cd (25.23 mg/g), Cu (21.63 mg/g), and Pb (20.63 mg/g) at 200 ppm. Scanning electron microscopy (SEM) explored the morphological changes in the mycelia of stressed fungi. Results of this study describe this delicate approach to be species and metal dependent and suggest a potential utilization of this fungal strain for the bioremediation of contaminated soils.

Heavy-Metal Tolerance of the Paecilomyces sp. BJKD1 Isolated from Coal Gangue

2013 ◽  
Vol 295-298 ◽  
pp. 1062-1065
Author(s):  
Xia Li ◽  
Yu Xiu Zhang ◽  
Tuan Yao Chai
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Superoxide Dismutase ◽  
Metal Pollution ◽  
Heavy Metal Pollution ◽  
Contaminated Soils ◽  
Metal Tolerance ◽  
Heavy Metal Tolerance ◽  
Coal Gangue ◽  
Heavy Metal Remediation

Microorganisms can be the important biosorbents for heavy metal remediation of contaminated soils or wastewater. A BJKD1 strain isolated from coal gangue piles was identified as a member of the Paecilomyces sp., which can tolerate to 3200 mg/L Cd2+. Favorable condition for BJKD1 growth was at pH 4.0-9.0. The presence of heavy metals, such as 36 mmol/L Cd2+, 1 mmol/L Cu2+, 80 mmol/L Zn2+, 7 mmol/L Ni2+ and 100 mmol/L Mn2+, retarded the growth of BJKD1, however, BJKD1 showed more tolerance for Mn2+. The activity of superoxide dismutase (SOD ) and Catalase (CAT ) in BJKD1 was increased under high metals concentration, indicated BJKD1 has the potential for biological repair of heavy metal pollution in coal gangue piles.

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