Toxic Environmental Pollutants Research Articles

Low-level cadmium exposure induced hormesis in peppermint young plant by constantly activating antioxidant activity based on physiological and transcriptomic analyses.

As one of the most toxic environmental pollutants, cadmium (Cd) has lastingly been considered to have negative influences on plant growth and productivity. Recently, increasing studies have shown that low level of Cd exposure could induce hormetic effect which benefits to plants. However, the underlying mechanisms of Cd-triggered hormesis are poorly understood. In this study, we found that Cd stress treatment showed a hormetic effect on peppermint and Cd treatment with 1.6 mg L-1 concertation manifested best stimulative effects. To explore the hormesis mechanisms of Cd treatment, comparative transcriptome analysis of peppermint young plants under low (1.6 mg L-1) and high (6.5 mg L-1) level of Cd exposure at 0h, 24h and 72h were conducted. Twelve of differentially expressed genes (DEGs) were selected for qRT-PCR validation, and the expression results confirmed the credibility of transcriptome data. KEGG analysis of DEGs showed that the phenylpropanoid biosynthesis and photosynthesis were important under both low and high level of Cd treatments. Interestingly, GO and KEGG analysis of 99 DEGs specifically induced by low level of Cd treatment at 72h indicated that these DEGs were mainly involved in the pathway of phenylpropanoid biosynthesis and their functions were associated with antioxidant activity. The expression pattern of those genes in the phenylpropanoid biosynthesis pathway and encoding antioxidant enzymes during 72h of Cd exposure showed that low level of Cd treatment induced a continuation in the upward trend but high level of Cd treatment caused an inverted V-shape. The changes of physiological parameters during Cd exposure were highly consistent with gene expression pattern. These results strongly demonstrate that low level of Cd exposure constantly enhanced antioxidant activity of peppermint to avoid oxidative damages caused by Cd ion, while high level of Cd stress just induced a temporary increase in antioxidant activity which was insufficient to cope with lasting Cd toxicity. Overall, the results presented in this study shed a light on the underlying mechanisms of the Cd-mediated hormesis in plant. Moreover, our study provided a safe method for the efficient utilization of mild Cd-contaminated soil as peppermint is an important cash plant.

A synergistic consequence of catalyst dosage, pH solution and reactive species of Fe-doped CdAl2O4 nanoparticles on the degradation of toxic environmental pollutants

Industrial wastewater treatment techniques are one of the biggest challenges of the scientific community that necessitate an increased consciousness to address water scarcity worldwide. Herein, an eco-friendly and cost-effective process was demonstrated to cope with tannery, textile and pharmaceutical dye wastes through the co-precipitation of highly reusable Fe-doped CdAl2O4 samples. The XRD studies exposed the space group R 3‾ with no secondary phase step being found for all samples. The outcomes of optical absorbance spectra demonstrate that Fe doping diminished the energy gap from 3.66 to 1.67 eV. HR-TEM images of existing spherical particles and some of the particles' rod-like structures with little agglomeration were found for Fe (0.075 M) doped CdAl2O4 nanoparticles. The PL emission outcomes show that Fe doping effectively prevented the charge carrier's recombination in CdAl2O4 during photocatalysis. All Fe-doped CdAl2O4 samples demonstrated higher photodegradation behaviors towards the effectual degradation of both dye solutions as compared to pure CdAl2O4 samples. Particularly, Fe (0.075 M)-doped CdAl2O4 samples exhibited improved photodegradation performance of 93 and 95% for both dye solutions. The amount of photodegradation was noticed to rely on dye pH, irradiation time, catalyst dosage, initial dye amount, and reactive species. The recyclability of the Fe (0.075 M) doped CdAl2O4 nanoparticles denotes that 78 and 82% of BB and BG were removed up to the 6th run of usage. The outcomes of trapping tests,.OH− and h+ radicals were the major Scavenging in the photodegradation reaction. COD studies affirmed the whole mineralization of BB and BG dye molecules. It is expected that our present examination could offer to improve various spinal oxide materials for the photodegradation activity of pharmaceutical contaminants and environmental issues and can also resolve energy storage applications.

A dual-mode sensor based on colorimetric and Tyndall effect of gold nanoparticles for ultra-sensitive detection of Hg2.

Mercury ion (Hg2+) is the most widespread and highly toxic environmental pollutant, which exerts numerous adverse effects on environmental and human health. There is an urgent need to develop a convenient method for detecting Hg2+. Herein, a novel dual-mode sensor based on colorimetric and Tyndall effect of gold nanoparticles was developed for ultra-sensitive determination of Hg2+. In this strategy, a polyA-modified Au probe with high uniformity was assembled successfully. Both modes were based on Hg2+-induced aggregation of the probes. Hg2+ was reflected according to the color variations of solution and the Tyndall effect of Au reporter. With the aid of a laser pointer, the Tyndall mode demonstrated about 615-fold improvement on sensitivity compared with the colorimetry way. Taking advantages of low cost and convenient assembly of polyA-based Au probe and the combination of colorimetry and Tyndall effect, our strategy determined the Hg2+ with high sensitivity and wide range. By changing probes or nanoparticles, the proposed strategy is expected to be a universal platform for detecting other analytes in environmental and even biological samples. A novel dual-mode sensor based on colorimetric and tyndall effect of gold nanoparticles for ultra-sensitive determination of Hg2+ was exploited.

Chitosan Nanoparticles as Potential Nano-Sorbent for Removal of Toxic Environmental Pollutants.

Adsorption is the most widely used technique for advanced wastewater treatment. The preparation and application of natural renewable and environmentally friendly materials makes this process easier and more profitable. Chitosan is often used as an effective biomaterial in the adsorption world because of its numerous functional applications. Chitosan is one of the most suitable and functionally flexible adsorbents because it contains hydroxyl (-OH) and amine (-NH2) groups. The adsorption capacity and selectivity of chitosan can be further improved by introducing additional functions into its basic structure. Owing to its unique surface properties and adsorption ability of chitosan, the development and application of chitosan nanomaterials has gained significant attention. Here, recent research on chitosan nanoparticles is critically reviewed by comparing various methods for their synthesis with particular emphasis on the role of experimental conditions, limitations, and applications in water and wastewater treatment. The recovery of pollutants using magnetic nanoparticles is an important treatment process that has contributed to additional development and sustainable growth. The application of such nanoparticles in the recovery metals, which demonstrates a "close loop technology" in the current scenarios, is also presented in this review.

ScRNA-seq analysis reveals toxicity mechanisms in shrimp hemocytes subjected to nitrite stress

In shrimp, hemocytes play an important role in detoxification and immune defense, and are where nitrite accumulates during exposure to this toxic environmental pollutant. However, the heterogeneity mechanisms of toxicity have not been reported under nitrite expose in shrimp. Here, we used single-cell RNA-seq to resolve 24,000 cells, which the responses of different cell populations of hemocytes under nitrite exposure in Penaeus vannamei. We identified 394 specific nitrite-responsive genes in 9 clusters of hemocytes, and found heterogeneity in the nitrite response of the three subpopulations of hemocytes (hyaline, semi-granular and granular cells). In hyaline, the response appeared modest, whereas nitrite-related dysregulation of metabolic processes in granular and semi-granular was pronounced. Ammonia nitrogen will rapidly accumulate in hemocytes of shrimp under nitrite stress. In semi-granular, excessive ammonia will interfere with oxidative phosphorylation and antioxidant system, thus inducing the production of reactive oxygen species. In granular, the abnormality of urea cycle caused by ammonia accumulation is the main toxic factor, which by inhibits arginase and arginine kinase. Collectively, our data provide a single-cell atlas for the dissection of shrimp hemocyte complexity, and reveal the toxicity mechanisms associated with nitrite exposure.

Enhancement mechanism of magnetite on the ball-milling destruction of perfluorooctane sulfonate by iron

Zero-valent iron (Fe) is commonly employed as an additive for the mechanochemical destruction (MCD) of organic pollutants. The poly- and perfluoroalkyl substances (e.g., perfluorooctane sulfonate, PFOS) are a class of toxic environmental pollutants that are difficult to effectively degrade due to their thermodynamic and chemical stability. In this study, magnetite (Fe3O4) was applied to improve the milling performance of Fe to PFOS and its promoting mechanisms were emphatically explored. The desulfurization rate was in ahead of the defluorination rate because the C–S bond is less stable than the C–F bonds in PFOS. Fe3O4 had an excellent reinforcement effect on the milling performance of Fe, which was mainly through accelerating the electron transfer as a conductor, reacting with Fe to produce FeO, and facilitating the formation of HO●. During the MCD of PFOS with Fe/Fe3O4 as an additive, HO● played a dominant role in the defluorination process (accounting for >67%). After the elimination of sulfonate group (−SO3−), the produced radical (C7F15CF2●) continued to react through two main pathways: one was the stepwise defluorination after hydrogenation, and the other one was oxidation reaction after alcoholization to yield the corresponding aldehydes and carboxylic acids. The optimum Fe fraction (MFe) was 30%, and air atmosphere was more effective than oxygen and nitrogen conditions. This study helps to comprehensively understand the role of Fe3O4 in defluorination and fills the gap of Fe/Fe3O4 application in the MCD of PFASs.

Current Trends in Toxicity Assessment of Herbal Medicines: A Narrative Review

Even in modern times, the popularity level of medicinal plants and herbal medicines in therapy is still high. The World Health Organization estimates that 80% of the population in developing countries uses these types of remedies. Even though herbal medicine products are usually perceived as low risk, their potential health risks should be carefully assessed. Several factors can cause the toxicity of herbal medicine products: plant components or metabolites with a toxic potential, adulteration, environmental pollutants (heavy metals, pesticides), or contamination of microorganisms (toxigenic fungi). Their correct evaluation is essential for the patient’s safety. The toxicity assessment of herbal medicine combines in vitro and in vivo methods, but in the past decades, several new techniques emerged besides conventional methods. The use of omics has become a valuable research tool for prediction and toxicity evaluation, while DNA sequencing can be used successfully to detect contaminants and adulteration. The use of invertebrate models (Danio renio or Galleria mellonella) became popular due to the ethical issues associated with vertebrate models. The aim of the present article is to provide an overview of the current trends and methods used to investigate the toxic potential of herbal medicinal products and the challenges in this research field.

Evaluation of the Therapeutic Effects of Moringa oleifera Seed Oil on Cadmium and Herbal Alcoholic Beverage–Induced Prefrontal Cortex Damage in Wistar Rats

The use of Moringa oleifera seed oil in the prevention of neurodegenerative diseases is on an increasing trend. Cadmium is one of the most toxic environmental pollutants causing many known damage to the brain, the consumption of herbal alcoholic beverages is known to cause neurodegeneration. The aim of this study was to investigate the ameliorative effects of Moringa oleifera seed oil on cadmium and herbal alcoholic beverage induced- damage to the frontal cortex of Wistar rats. Eighty Wistar rats were divided into eight groups of 10 rats each. Group A served as a control which received 2.5mg/kgbw phosphate buffer intra-peritoneally, while group F served as Moringa-treated control and received oral administration of 2.0 mg/kgbw Moringa oleifera oil. Groups B1, B2, D and E were injected intra-peritoneally with 3.5mg/kgbw CdSO4.8H2O single dose. Group C1, C2 and D received oral administration of 0.5 ml Herbal Alcoholic Beverage (HAB) and group B2, C2and E were administered orally with 2.0mg/kgbw Moringa oleifera oil for four weeks followed by sacrificed. Quantitative enzymes and biochemical antioxidant markers showed that cadmium and HAB administration caused a significant increase in AchE, SDH, CAT, GPx and MDA levels and decrease in SOD level. Conversely, there were significant decrease in AchE, SDH, CAT, GPx and MDA and increased SOD level upon administration of Moringa oleifera oil. Moringa oleifera seed oil has natural antioxidant constituents that ameliorated damage caused by Cd and HAB.

Integrated system for rapid enrichment and detection of airborne polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are extremely toxic environmental pollutants, which are harmful to the human body. Direct collection and analysis of airborne PAHs is essential for air quality monitoring. Herein, we demonstrated an integrated system for airborne PAHs enrichment and detection. The enrichment cube was composed of channels with threaded structures and curved channels, which had high capture efficiency. Then PAHs-carried particles could be crushed into the detection chip for testing. The whole process took about 25 min (5 min for PAHs enrichment and 20 min for PAHs test). The limit of detection was 3.3 ng/m3, which could meet the needs of daily analysis. It had the advantages of low cost, low reagent consumption, simple operation, semi-automatic operation, high sensitivity, high speed and high throughput compared with conventional techniques, showing the potential for becoming an air pollution monitoring platform.

HSP27–HSP40–HSP70–HSP90 pathway participated in molecular mechanism of selenium alleviating lead-caused oxidative damage and proteotoxicity in chicken Bursa of Fabricius

Lead (Pb), a toxic environmental pollutant, is hazardous to the health of humans and birds. Bursa of Fabricius (BF) is a unique organ of birds. Toxic substances can attack BF and induce proteotoxicity. Increased heat shock proteins (HSPs) can induce oxidative damage. Selenium (Se) can alleviate harmful substance-caused oxidative damage. This study aimed to investigate whether Pb can cause oxidative damage and proteotoxicity, as well as Se reverse Pb-caused chicken BF toxicity. A model of chickens treated with Se and Pb alone and in combination was established. BFs were collected on days 30, 60, and 90. H&E and qRT-PCR were performed to observe the microstructure and to detect HSP27, HSP40, HSP60, HSP70, and HSP90 mRNA levels, respectively, in BFs. Multivariate correlation analysis and principal component analysis were conducted to explore the correlation among the five HSPs. In our results, Pb caused BF damage and up-regulated the five HSPs at three time points, causing oxidative damage and proteotoxicity via HSP27–HSP40–HSP70–HSP90 pathway. Furthermore, Pb caused time-dependent stress on HSP27, HSP40, HSP60, and HSP70. In addition, Se relieved Pb-caused damage and up-regulation of HSPs. Taken together, we concluded that Se alleviated Pb-caused oxidative injury and proteotoxicity in chicken BFs via the HSP27–HSP40–HSP70–HSP90 pathway.

A ratiometric lysosome-targeted fluorescent probe for imaging SO2 based on the coumarin-quinoline-julolidine molecular system

Similar to nitric oxide (NO) molecule, carbon monoxide (CO) molecule and hydrogen sulfide (H2S) molecule, sulfur dioxide (SO2) is also considered to be another important endogenous signaling molecule. SO2 derivatives are widely used as food antioxidants and antimicrobial agents. However, SO2 is also a toxic environmental pollutant and intake of elevated levels of sulfites can lead to diarrhea, low blood pressure and allergic and asthmatic reactions in susceptible people. The specific physiological effects and transformation processes of SO2 and its derivatives are not well understood due to the limitations of existing detection methods. Therefore, it is an urgent need to develop highly sensitive, high-resolution, real-time in situ assays. Herein, we specifically designed a ratiometric near-infrared fluorescent probe CQT for detecting SO2 derivatives. After the reaction of CQT with HSO3−/SO32−, a gradual decrease in red fluorescence at 662 nm accompanied by an enhanced blue fluorescence at 489 nm, reaching a detection range of 2.8–80 μM. In addition, we found that CQT had high energy transfer efficiency, large Stokes shift and low detection limit, which meant that CQT could sensitively monitor small changes of SO2 concentration in cells and accurately target lysosomes.

Cadmium exposure promotes thyroid pyroptosis and endocrine dysfunction by inhibiting Nrf2/Keap1 signaling

Cadmium (Cd) is a ubiquitous toxic metal and environmental pollutant. Increasing studies have shown that Cd exposure increases the incidence of various endocrine system diseases, including thyrotoxicity reflected by thyroid structural damage and endocrine toxicity. However, the observed outcomes are complex and conflicting, leading to the mechanism of Cd-induced thyrotoxicity remaining obscure. In this study, 4-week-old male C57BL/6 mice were given 2 or 7 mg/kg Cadmium Chloride (CdCl2) intragastrically for 4 and 8 weeks, and the Cd-mediated thyrotoxicity was evaluated by determining alterations in thyroid structure and endocrine function, and alterations of oxidant stress, apoptosis, and pyroptosis. Our data showed that Cd exposure could reduce body weight and induce thyrotoxicity by impairing thyroid follicular morphology and endocrine function, accompanied by elevated oxidative stress and apoptosis, macrophage infiltration, and inflammatory cytokine secretion. Importantly, Cd significantly promoted thyroid follicular cell pyroptosis by increasing Nlrp3, Asc, Caspase-1, Gsdmd, IL-1β, and IL-18 expression. Mechanistical analysis suggested that Cd treatment could inhibit antioxidant pathway by downregulating antioxidant response protein, Nrf2, and upregulating its negative feedback regulator, Keap1. Collectively, our in vivo findings suggest that Cd exposure could facilitate thyroid follicular cell pyroptosis by inhibiting Nrf2/Keap1 signaling, thereby disrupting thyroid tissue structure and endocrine function, which offers novel insights into the Cd-mediated detrimental consequences on thyroid homeostasis.

Utilization of marine organisms for the green synthesis of silver and gold nanoparticles and their applications: A review

Nanobiotechnology has tremendous potential to support eco-friendly systems and industrial sustainability through the production of metal nanoparticles using biological sources. For chemical methods are supposed highly toxic reagents, carcinogenic solvent, and environmental pollution. On the other hand, some of physical methods are require high energy consumption and expensive equipment. Moreover, both methods also resulted difficulties in controlling crystal growth and then triggered particle aggregation due to need additional steps by adding stabilizer. Metal nanoparticles are utilized in biosensing, medical, or pharmaceutical applications. Various types of marine organisms, including bacteria, fungi, vertebrates, invertebrates, and diverse algae, possess the ability to withstand environmental pressure and the capability to grow in the presence of high metal concentrations to synthesize metal nanoparticles. Furthermore, from the marine organisms are a source of active compound as reducing and stabilizing agents present in the biological extract. Concerning the biosynthesis of nanoparticles, gold (Au) and silver (Ag) nanoparticles have been most extensively investigated. Au and Ag nanoparticles have been synthesized using marine organisms with various sizes and shapes such as spherical, triangular, cubical, and polygonal. These nanoparticles are primarily applied in the medical field owing to their antibacterial, antioxidant, and anti-inflammatory properties. This review provides a comprehensive description of the biosynthesis of Au and Ag nanoparticles using marine organisms, including the method, mechanism of action, and their applications.

Electrolysis‐Mediated Rapid Synthesis of Highly Fluorescent and pH Responsive Congo Red Carbon Nanodots for Cu2+ Sensing

AbstractCopper ion (Cu2+) is a highly toxic environmental pollutant with bioaccumulative properties, making its rapid and selective detection important for environmental and health monitoring. In this study, highly fluorescent carbon nanodots by the electrolysis of Congo Red are developed, which are denoted as CR‐CDs and exhibit high quantum yield and pH‐responsive character. The pH response behavior is applied for pH test in soft drinks with high accuracy. Cu2+ causes dramatic fluorescence quenching due to the formation of cupric amine complex and the occurrence of inner filter effect. The signal changes in fluorescence spectroscopy allow a detection limit of Cu2+ at 0.13 μM. The response is highly specific toward Cu2+ over other metal ions. In addition, the practicability of the sensor is validated by accurate Cu2+examination in running water samples.

In-vitro cell culture model to determine toxic effects of soil Arsenic due to direct dermal exposure

Arsenic (As) is one of the most toxic environmental pollutants, classified as a Class I carcinogen. Anthropogenic activities have led to an increase in As contamination of soils. Using animal models to study the health impacts of As is time and cost-prohibitive, hence attempts have been made to develop in-vitro cell culture models. However, most studies so far have not represented realistic environmental exposure conditions. We exposed Human Immortalized Keratinocyte (HaCaT) and Primary Human Dermal Fibroblasts (HDFa) cells to the water-soluble fraction of arsenic extracted from As spiked Immokalee soil to study the effect of soil As on skin cells. The impact of As was determined through cell viability, cell migration, and quantitative assessment of the expression of cadherins, CD44, and Zeb1 using Western Blotting and In-cell Western. Our data indicated that HaCaT cells were more susceptible to As-induced cellular transformation than HDFa cells. At concentrations above 225 mg/kg of soil As, cellular responses were impacted, and changes in the expression of proteins were observed in HaCaT cells. The work presented here is a methodical approach to studying the impacts of toxic elements such as As through innovative cellular models using realistic environmental conditions, that can be readily adapted for different exposure pathways. • Human skin cells exposed to the water-soluble soil As showed decreased viability. • Uptake of soil As by keratinocytes was higher than that of fibroblasts. • Soil As impacted cell-to-cell adhesion and migration in skin cells. • Soil As induced epithelial to mesenchymal transformation in skin cells. • A human cell culture model to test soil As toxicity was developed.

The scleractinian coral Pocillopora damicornis relies on neuroendocrine regulation to cope with polycyclic aromatic hydrocarbons under heat stress

Polycyclic aromatic hydrocarbons (PAHs) are highly toxic environmental pollutants and are threatening scleractinian corals. In this study, PAHs treatment did not induce significant physiological responses of the coral Pocillopora damicornis and its algal symbionts, but biological processes including response to toxin, drug metabolic, and oxidation reduction were triggered at the mRNA level. These results implied that PAHs could be a group of slow-acting environmental toxicants, whose effects were moderate but persistent. Besides, it was interesting to find that PAHs activated the neuroendocrine system in the coral by triggering the expression of monoaminergic and acetylcholinergic system related genes, indicating that PAHs might function as environmental hormones. Moreover, the combined treatments of PAHs and heat caused a much obvious effect on the coral and its algal symbionts by elevating antioxidant activity and suppressing photosynthesis in the symbionts. Results from the transcriptome data further indicated that corals might perform stress responses upon PAHs and heat challenges through the TNF and apoptosis pathways, which perhaps was modulated by the neuroendocrine system of corals. Collectively, our survey demonstrates that the PAHs can function as environmental hormones and activate the neuroendocrine regulation in scleractinian corals, which may contribute to the stress responses of symbiotic association by modulating photosynthesis, antioxidation, and apoptosis.

Concentration, Source, and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons: A Pilot Study in the Xuanwei Lung Cancer Epidemic Area, Yunnan Province, China

Polycyclic aromatic hydrocarbons (PAHs) are toxic and hazardous volatile environmental pollutants that have been studied as possible major causative agents of lung cancer in Xuanwei. In this paper, indoor and outdoor PM2.5 samples were collected from two homes at different time periods in Hutou, the lung cancer epidemic area in Xuanwei. The results showed that PAH pollution levels from coal combustion in Xuanwei lung cancer epidemic area were significant. The mass concentrations of total PAHs, major carcinogenic compounds, and benzo[a]pyrene-based equivalent concentration (BaPeq) were significantly higher in the coal-using home than in the electricity-using home. For the coal-using home, the PAHs were mainly derived from coal combustion. For the electricity-using home, the PAHs might have been a combination of traffic and coal combustion sources. The human health risk due to inhalation exposure to the PAHs was represented by the incremental lifetime cancer risk (ILCR) of the inhalation exposure. The results showed that the indoor cancer risk for the coal-using home in Xuanwei is higher than that of the electricity-using home and much higher than that of Chinese megacities such as Beijing and Tianjin. Long-term exposure to indoor coal-burning environments containing high levels of PAHs may be one of the main reasons for the high incidence of lung cancer in Xuanwei.

Proteomic analysis of T. qataranse exposed to lead (Pb) stress reveal new proteins with potential roles in Pb tolerance and detoxification mechanism

Soil lead (Pb) contamination is one of the environmental problems facing the modern world. Sources of Pb in soil include industrial activities such as mining and smelting processes, agricultural activities such as application of insecticide and municipal sewage sludges, and urban activities such as use of lead in gasoline, paints, and other materials. Phytoremediation is the direct use of living green plants and is an effective, cheap, non-invasive, and environmentally friendly technique used to transfer or stabilize all the toxic metals and environmental pollutants in polluted soil or groundwater. Current work in this area is invested in elucidating mechanisms that underpin toxic-metal tolerance and detoxification mechanisms. The present study aims to gain insight into the mechanisms of Pb tolerance in T. qataranse by comparative proteomics. MALDI-TOF/MS and in silico proteome analysis showed differential protein expression between treated (50 mg kg⎯1 Pb) and untreated (0 mg kg⎯1 Pb) T. qataranse. A total of eighty-six (86) differentially expressed proteins, most of which function in ion and protein binding, antioxidant activity, transport, and abiotic response stress, were identified. In addition, essential stress-regulating metabolic pathways, including glutathione metabolism, cellular response to stress, and regulation of HSF1-mediated heat shock response, were also enriched. Also, at 52- and 49-kDa MW band areas, up to six hypothetical proteins with unknown functions were identified. Of these, protein AXX17_AT2G26660 is highly rich in glycine amino acid residues (up to 76%), suggesting that it is a probable glycine-rich protein (GRP) member. Although GRPs are known to be involved in plant defense against abiotic stress, including salinity and drought, there is no report on their role on Pb tolerance and or detoxification in plants. Further enrichment analysis in the current study reveals that the hypothetical proteins do not interact with known proteins and are not part of any enriched pathway. However, additional research is needed to functionally validate the role of the identified proteins in Pb detoxification mechanism.

Compositional, genetic and functional characterization of soil culturable microbial communities in polychlorinated dibenzo-p-dioxins/furans contaminated soil

Dioxins (PCDD/Fs) are one of the most toxic environmental pollutants known to date. Due to their structural stability and extreme hydrophobicity dioxins persist in the ecosystems and can be bioaccumulated to critical levels in both human and animal food chains. Soils are the most important reservoirs of dioxins, thus soil microbes are highly exposed to dioxins, impacting their diversity, genetics and functional characteristics. To experimentally evaluate these effects, the diversity and functionality of soil microbes were assessed in seven local sites potentially exposed to PCDD/Fs.Concentration of dioxins in soils samples was firstly determined and the soils cultivable microbes were identified and molecularly characterized as a function of their in vitro ability to degrade the TCDD. Our results revealed that the diversity of microbial communities largely varied among the sites and was likely inversely proportional to their level of contamination with PCDD/Fs. Furthermore, the genetics profiling of dioxin-degrading bacteria revealed that the Cytochrome P450 CYPBM3-positive species largely belong to the genus Bacillus and were randomly distributed among the soils samples, while the angular dioxygenase (AD)-positive species were mainly found in highly polluted soils with a major presence of the genus Pseudomonas. Finally, the functionality of dioxin-biodegrading genes (AD or CYPBM3), was confirmed by the ability of bacteria to consume 2,3,7,8-TCDD, and this was synchronized with an induced level of both pathways. Our results suggest that different dioxin-metabolizing pathways exist under the same environmental conditions and work differentially for an effective removal of PCDD/Fs.

White adipose tissue as a target for cadmium toxicity.

Cadmium (Cd) is a widespread heavy metal known as a toxic environmental pollutant. Cd exposure is threatening due to its bioaccumulation trait in living systems that exceeds 35 years without a beneficial biological role. Acute exposure to high Cd doses was reported to impact adipose tissue (AT) function adversely. The main aim of this study is to investigate the effect of low-dose chronic Cd exposure on the genes involved in adipose tissue (AT) functions. Adult male Sprague-Dawley rats were exposed to a low Cd dose (15 mg/kg B.W./day) for 10 weeks. Then, three AT depots-subcutaneous AT (SUB-AT), abdominal AT (AB-AT), and retroperitoneal AT (REtrop-AT) were excised for Cd accumulation measures and gene expression analysis. Adiponectin and leptin gene expression levels were investigated as markers for adipocytes function and homeostasis. Our results showed that Cd accumulated in all the tested adipose depots, but SUB-AT was found to be the depot to most accumulate Cd. Also, it was exhibited that chronic exposure to low Cd doses altered the gene expression of adipocytokines. The levels of adiponectin and leptin mRNA expression were downregulated in all tested AT-depots after Cd exposure. The significant adverse effect on SUB-AT compared to other depots indicates different responses based on AT depots location toward Cd exposure. Collectively, these results suggest a toxic effect of Cd that influenced adipocyte function.