Non-protein Thiols Research Articles

NFE2L2 and SLC25A39 drive cuproptosis resistance through GSH metabolism

Cuproptosis is a recently discovered form of regulated cell death triggered by mitochondrial copper accumulation and proteotoxic stress. Here, we provide the first evidence that glutathione (GSH), a major non-protein thiol in cells, acts as a cuproptosis inhibitor in pancreatic ductal adenocarcinoma (PDAC) cells. Mechanistically, GSH inhibits cuproptosis by chelating copper, contrasting its role in blocking ferroptosis by inhibiting lipid peroxidation. The classical cuproptosis inducer, ES-Cu (elesclomol plus copper), increases the protein stability of the transcription factor NFE2L2 (also known as NRF2), leading to the upregulation of gene expression of glutamate-cysteine ligase modifier subunit (GCLM) and glutamate-cysteine ligase catalytic subunit (GCLC). GCLM and GCLC are rate-limiting enzymes in GSH synthesis, and increased GSH is transported into mitochondria via the solute carrier family 25 member 39 (SLC25A39) transporter. Consequently, genetic inhibition of the NFE2L2-GSH-SLC25A39 pathway enhances cuproptosis-mediated tumor suppression in cell culture and in mouse tumor models. These findings not only reveal distinct mechanisms of GSH in inhibiting cuproptosis and ferroptosis, but also suggest a potential combination strategy to suppress PDAC tumor growth.

OsbHLH6, a basic helix-loop-helix transcription factor, confers arsenic tolerance and root-to-shoot translocation in rice.

Arsenic (As) is extremely toxic to plants, posing a serious concern for food safety. Identification of genes responsive to As is significative for figuring out this issue. Here, we identified a bHLH transcription factor OsbHLH6 that was involved in mediating the processes of As tolerance, uptake, and root-to-shoot translocation in rice. The expression of OsbHLH6 gene was strongly induced after 3 and 48 h of arsenite [As(III)] treatment. The OsbHLH6-overexpressed transgenic rice (OE-OsbHLH6) was sensitive to, while the knockout mutant of OsbHLH6 gene (Osbhlh6) was tolerant to As(III) stress by affecting the contents of reactive oxygen species (ROS) and non-protein thiols (NPT), etc. Knockout of OsbHLH6 gene increased significantly the As concentration in roots, but decreased extensively As accumulation in shoots, compared to that in OE-OsbHLH6 and WT plants. The transcripts of phytochelatins (PCs) synthetase encoding genes OsPCS1 and OsPCS2, as well as As(III) transporter encoding genes OsLsi1 and OsABCC1 were greatly abundant in Osbhlh6 mutants than in OE-OsbHLH6 and WT plants under As(III) stress. In contrast, the expression of OsLsi2 gene was extensively suppressed by As(III) in Osbhlh6 mutants. OsbHLH6 acted as a transcriptional activator to bind directly to the promoter and regulate the expression of OsPrx2 gene that encodes a peroxidase precursor. Moreover, overexpression of OsbHLH6 gene resulted in significant change of expression ofamounts of abiotic stress-related genes, which might partially contribute to the As sensitivity of OE-OsbHLH6 plants. These findings may broaden our understanding of the molecular mechanism of OsbHLH6-mediated As response in rice and provide novel useful genes for rice As stress-resistant breeding.

Assessing antioxidant responses in C6 and U-87 MG cell lines exposed to high copper levels

Copper excess has been tested as an anticancer therapy, due to its properties to generate oxidative stress resulting in tumoral cell death. Thus, this study aimed to evaluate the impact of copper excess on oxidative stress and antioxidant responses in glioma cells, establishing the antioxidant system as a target of copper toxicity in tumoral cells. C6 and U-87 MG cells were exposed to CuSO4 (0–600 μM) for 24-48 h. SOD, CAT, GPx, GR, and CK activities, protein and non-protein thiol levels (PSH and NPSH), and O2− production were assessed, alongside SOD1, GPx1, and GR gene expression. Results revealed a decrease in GPx, GR, and CAT activity after CuSO4 exposure in both cell lines over 24-48 h, while SOD activity initially increased, then declined after 48 h. CK activity was also decreased in C6 cells. NPSH and PSH levels dropped after 24 h, and O2− production was observed in all CuSO4 concentrations. GR mRNA was reduced in both cell lines, contrasting with increased GPx1 mRNA in C6. U-87 MG cells exhibited higher levels of SOD1 mRNA, while C6 cells displayed lower expression. Our findings suggest that copper excess limits antioxidant enzyme activity and thiol levels, particularly in the C6 cells, likely attributable to oxidative stress or direct copper-enzyme interactions. Moreover, our results imply differences in copper toxicity regarding the cell lineage used, highlighting the importance of analyzing high copper levels effects in different models. Moreover, it could be proposed that the antioxidant system is a target of copper toxicity, contributing to glioma cell death.

Copper sulfate-induced stress in Spinach: Metabolic pathway disruption and plant response

Copper sulfate (CuSO4) stress profoundly affects plant growth by interfering with key metabolic pathways. This disruption leads to significant alterations in various physiological parameters, ultimately impacting the overall health and productivity of the plant. This study assessed the impact of CuSO4 stress on spinach (Spinacia oleracea L.) through a pot experiment using CuSO4 concentrations of 0, 75, 125, and 175 ppm. We noticed that at 75 ppm, CuSO4 improved plant height and the concentration of soluble sugar and ascorbic acid compared to the control. Additionally, amino acid, phenol, proline, fresh weight, and moisture content peaked at 175 ppm. Conversely, at 125 and 175 ppm, plant height, dry weight, leaf area, and concentrations of ascorbic acid and sugar significantly decreased. Moreover, at 175 ppm, there were substantial decreases in chlorophyll a (14.8%), chlorophyll b (73.6%), carotenoids (15%), and photosynthetic rates compared to the control. However, the chlorophyll a to chlorophyll b ratio increased by 29.53% at 175 ppm. In addition, protein and phenol contents diminished at 75 and 125 ppm. Elevated CuSO4 levels increased non-protein thiol levels while reducing the activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione peroxidase. Stress hormones such as abscisic acid, jasmonic acid, and ethylene increased with CuSO4 stress, whereas growth hormones indol-acetic acid and gibberellic acid declined. This study demonstrates that spinach shows improved growth and metabolic function at 75 ppm CuSO4, indicating tolerance to mild stress. However, higher CuSO4 concentrations (125 and 175 ppm) significantly reduce growth parameters, chlorophyll content, and enzyme activities, highlighting the need for careful CuSO4 management in agriculture to avoid adverse effects on plant health and productivity.

Mitigating aluminum chloride-induced toxicity in Drosophila melanogaster with peptide fractions from Euphorbia species

This study assessed the antioxidative and protective effects of peptide extracts from selected Euphorbia species on Aluminum Chloride (AlCl3)-induced toxicity in Drosophila melanogaster. Euphorbia humifusa (EHU), Euphorbia hirta (EHI), and Euphorbia graminae (EHG) were screened for bioactive peptides. The crude peptide extract and partially purified peptide fractions of all the plants were subjected to preliminary antioxidants activities through 2, 2-diphenyl-1-picrylhyhdrazyl (DPPH), and nitric oxide (NO) scavenging activities. The most active peptide fraction was subjected to biochemical studies using Drosophila melanogaster. Flies were treated with AlCl3 (100 mg/kg diet), peptide fraction (5 and 10 mg/kg diet), and cotreatment of AlCl3 and the fraction, respectively. After treatment, flies were homogenized for the determination of total thiol and Glutathione (non-protein thiol) content, catalase and Glutathione-S-transferase activities, and nitric oxide (nitrite/nitrate) and hydroperoxide levels. The antioxidant screening revealed that the peptide fraction from Euphorbia humifusa (PEHU) was the most significant compared to the control (ascorbic acid). The PEHU (5 and 10 mg/kg diet) maintained the redox status of the flies in the biochemical study. The PEHU significantly counteracted AlCl3-induced reduction in antioxidants (catalase, GST, GSH and Total thiol), increased nitric oxide levels, and acetylcholinesterase activity and prevented behavioral deficits flies. Hence, the peptide fraction of Euphorbia humifusa may shield against the life-threatening effects of free radicals associated with aluminum chloride toxicity.

Overexpression of bacterial γ-glutamylcysteine synthetase increases toxic metal(loid)s tolerance and accumulation in Crambe abyssinica.

Transgenic Crambe abyssinica lines overexpressing γ-ECS significantly enhance tolerance to and accumulation of toxic metal(loid)s, improving phytoremediation potential and offering an effective solution for contaminated soil management. Phytoremediation is an attractive environmental-friendly technology to remove metal(loid)s from contaminated soils and water. However, tolerance to toxic metals in plants is a critical limiting factor. Transgenic Crambe abyssinica lines were developed that overexpress the bacterial γ-glutamylcysteine synthetase (γ-ECS) gene to increase the levels of non-protein thiol peptides such as γ-glutamylcysteine (γ-EC), glutathione (GSH), and phytochelatins (PCs) that mediate metal(loid)s detoxification. The present study investigated the effect of γ-ECS overexpression on the tolerance to and accumulation of toxic As, Cd, Pb, Hg, and Cr supplied individually or as a mixture of metals. Compared to wild-type plants, γ-ECS transgenics (γ-ECS1-8 and γ-ECS16-5) exhibited a significantly higher capacity to tolerate and accumulate these elements in aboveground tissues, i.e., 76-154% As, 200-254% Cd, 37-48% Hg, 26-69% Pb, and 39-46% Cr, when supplied individually. This is attributable to enhanced production of GSH (82-159% and 75-87%) and PC2 (27-33% and 37-65%) as compared to WT plants under AsV and Cd exposure, respectively. The levels of Cys and γ-EC were also increased by 56-67% and 450-794% in the overexpression lines compared to WT plants under non-stress conditions, respectively. This likely enhanced the metabolic pathway associated with GSH biosynthesis, leading to the ultimate synthesis of PCs, which detoxify toxic metal(loid)s through chelation. These findings demonstrate that γ-ECS overexpressing Crambe lines can be used for the enhanced phytoremediation of toxic metals and metalloids from contaminated soils.

Kolaviron: a Bioflavonoid from Seed Extract of Garcinia kola Attenuates Chromium (VI)-Induced Gut Dysfunction and Oxidative Damage in Drosophila melanogaster.

Hexavalent chromium [Cr(VI)] is of public health significance due to its toxicity and carcinogenic effects. Kolaviron, a bio-flavonoid fraction from Garcinia kola seed, has been reported to possess gastroprotective and antioxidative properties. We hypothesize that Kolaviron-fortified diet will attenuate chromium (VI)-induced gut dysfunction and oxidative damage in Drosophila melanogaster. We exposed D. melanogaster (Oregon strain of 1-3days old of both male and female) to a 1.0mg/kg diet of chromium (VI), with or without Kolaviron (100mg/kg diet) orally for 5days. We evaluated markers of oxidative stress (total peroxide and protein carbonyl), antioxidative status (total thiols (T-SH), non-protein thiols (NP-SH), and catalase), and inflammatory (nitric oxide (nitrite and nitrate) and gut's morphology. The data indicated that Kolaviron ameliorated chromium (VI)-induced reduction in the levels of T-SH, NP-SH, and catalase activity (p < 0.05). In addition, Kolaviron attenuated chromium (VI)-induced elevation of total peroxide, protein carbonyl, and nitric oxide (p < 0.05). Kolaviron offered a protective role in chromium VI-induced toxicity in the gut of D. melanogaster. This study provided further insights into the protective mechanisms of Kolaviron against chromium (VI)-induced toxicity in D. melanogaster by maintaining epithelial integrity of the gut and oxidative stress-antioxidant balance.

Exogenous γ-aminobutyric acid (GABA) enhances rye (Secale cereale) seedling resistance to combined freeze-thaw and cadmium stress.

Freeze-thaw is a common stress at high altitudes in northern China. There is a risk of cadmium (Cd) contamination in the region. γ-aminobutyric acid (GABA) is a natural product that regulates plant growth. Rye (Secale cereale ) was used as research material to investigate the physiological effects of exogenous GABA on rye seedlings under the single and combined stresses of freeze-thaw and cadmium. The results showed that the combined stress severely inhibited shoot length, root length, fresh weight, and dry weight, increased malondialdehyde and hydrogen peroxide contents, and significantly decreased superoxide dismutase (SOD) activity. Foliar application of 5mM GABA alleviated the negative effects of stress on seedling growth, increased soluble protein content, and reduced malondialdehyde and hydrogen peroxide contents. Exogenous GABA application also enhanced the activities of SOD and peroxidase (POD). Additionally, the presence of exogenous GABA activated the GABA metabolic process and encouraged the accumulation of phytochelatins, glutathione, and non-protein thiol. These results indicate that exogenous GABA can effectively improve the resistance of rye seedlings to freeze-thaw and Cd by regulating the antioxidant enzyme system and enhancing its own detoxification mechanism, and they provide a basis for future applications of exogenous GABA, which is beneficial for ecological protection.

Extract from Falcaria vulgaris loaded with exosomes for the treatment of hypertension in pregnant mice: In vitro and In vivo investigations.

Hypertensive disorders during pregnancy pose significant risks to both maternal and fetal health, necessitating safe and effective therapeutic interventions. This study aimed to investigate the potential of an extract derived from Falcaria vulgaris (FV), loaded with exosomes to form the Exo/FV complex, as a novel therapeutic agent for the management of hypertension in pregnant mice: antioxidants, antimicrobials, and phenolic compounds present in FV lower blood pressure. The isolation of exosomes was done by ultracentrifugation methods and the FV was loaded into the exosomes by electroporation method. The Exo/FV was found to be spherical with diameter ranges from 20 to 30nm and they were tested for biocompatibility in NHI 3T3 cell lines and found to be effective. This research investigated invivo hypertension in mice induced by L-NAME and treated with FV and Exo/FV and found that AChE and MAO determine mice's redox state tends to reduce blood pressure. Increased non-protein thiol (NP-SH) and decreased lipid peroxidation were also found, and PDE-5, ACE, Arginase, and MDA activity has also been tested. This analysis showed that Exo/FV effectively treated hypertension during pregnancy.

Optimizing Oxalic Acid Application Regime to Maximize Sunflower Remediation Efficacy in Cd-Contaminated Soils

The exogenous application of oxalic acid is a potential approach to amplifying phytoremediation performance on Cd-contaminated soils. However, few studies explore the optimal oxalic acid application regime from a perspective of coupling different concentrations and timings to maximize Cd removal rate. Given this, a pot experiment was conducted using oil sunflower (Helianthus annuus L.) as the test plant. Oxalic acid was added to the pots at concentrations of 1, 2, 3, 4, 5, and 6 mmol/kg at 20, 30, 40, and 50 days after emergence. A control (CK) without exogenous oxalic acid was also included. We examined the discrepancies in various soil Cd forms, sunflower height, plant non-protein thiol (NPT) levels, and soil Cd remediation efficiency under different oxalic acid application regimes. The results showed that applying oxalic acid at a concentration of 4 mmol/kg reduced the proportion of Fe-Mn oxide Cd and organic Cd compared to the control (CK), while increased the proportion of available Cd. The optimal application time is 30 or 40 days after emergence. The addition of exogenous oxalic acid promoted the growth of sunflowers, with the greatest increase in plant height observed when 4 mmol/kg oxalic acid was applied at 30 days after emergence. Exogenous oxalic acid enhanced the absorption of Cd by sunflower roots, with the total Cd accumulation in roots, stems, and leaves being higher than in the control (CK). When 4 mmol/kg oxalic acid was applied at 30 days after emergence, the total Cd accumulation in roots, stems, and leaves was highest. Under different application times and concentration levels of oxalic acid, Cd accumulation was highest in roots, followed by leaves, with stems showing the lowest accumulation. The NPT content in each part is as follows: root &gt; stem &gt; leaf. Applying 5 mmol/kg oxalic acid after 30 days of sunflower emergence resulted in relatively higher total NPT content in roots, stems, and leaves compared to the control (CK). The TOPSIS model was used for comprehensive evaluation, which showed that 4 mmol/kg oxalic acid application at 30 days after emergence could be used as the optimal oxalic acid application regime for phytoremediation. These findings indicate that the addition of oxalic acid effectively promoted the absorption of Cd by sunflower and increased the efficiency of Cd removal from the rhizosphere soil, with the optimal removal of soil Cd achieved by applying oxalic acid at a concentration of 4 mmol/kg 30 days after the emergence of oilseed sunflower seedlings.

Protective role of hesperetin in Drosophila melanogaster model of ferrous sulphate-induced toxicity

The toxicological hazard of iron-containing products is a public health concern that inspires research in identifying and developing readily available, inexpensive antidotes. Natural products, like plant-sourced antioxidants, can be of great value in this regard. Hesperetin a flavonoid abundantly present in citrus fruits is known to possess a diverse pharmacological and antioxidant attribute. The present study investigated the alleviation of detrimental effects of ferrous sulphate (FeSO4) by hesperetin in Drosophila melanogaster. Flies were exposed to FeSO4 (10 µM) alone or supplemented with hesperetin (50 or 100 µM) via diet for 7 consecutive days. Antioxidant enzyme activities, non-enzymatic antioxidant levels, acetylcholinesterase activity and oxidative stress markers were then measured. Hesperetin supplementation significantly (p < 0.05) attenuated FeSO4-induced oxidative stress by enhancement of enzymic antioxidants (catalase and glutathione-S-transferases) activities, preservation of non-enzymic antioxidants (total thiols and non-protein thiols), and reduction of other markers of oxidative stress (hydrogen peroxide, protein carbonyl and lipid peroxidation) in D. melanogaster. In addition, hesperetin supplementation decreased nitric oxide levels and enhanced acetylcholinesterase activity. Furthermore, hesperetin supplementation improved FeSO4-induced locomotor deficit, while there was no significant difference in cell viability (mitochondrial metabolic rate) in the treatment groups. This study suggests that hesperetin might be a promising functional agent in preventing iron toxicity and similar metal-induced impairments.

Effects of Nitrogen Deficiency on the Photosynthesis, Chlorophyll a Fluorescence, Antioxidant System, and Sulfur Compounds in Oryza sativa.

Decreasing nitrogen (N) supply affected the normal growth of Oryza sativa (O. sativa) seedlings, reducing CO2 assimilation, stomatal conductance (gs), the contents of chlorophylls (Chl) and the ratio of Chl a/Chl b, but increasing the intercellular CO2 concentration. Polyphasic chlorophyll a fluorescence transient and relative fluorescence parameters (JIP test) results indicated that N deficiency increased Fo, but decreased the maximum quantum yield of primary photochemistry (Fv/Fm) and the maximum of the IPphase, implying that N-limiting condition impaired the whole photo electron transport chain from the donor side of photosystem II (PSII) to the end acceptor side of PSI in O. sativa. N deficiency enhanced the activities of the antioxidant enzymes, such as ascorbate peroxidase (APX), guaiacol peroxidase (GuPX), dehydro-ascorbate reductase (DHAR), superoxide dismutase (SOD), glutathione peroxidase (GlPX), glutathione reductase (GR), glutathione S-transferase (GST) and O-acetylserine (thiol) lyase (OASTL), and the contents of antioxidant compounds including reduced glutathione (GSH), total glutathione (GSH+GSSG) and non-protein thiol compounds in O. sativa leaves. In contrast, the enhanced activities of catalase (CAT), DHAR, GR, GST and OASTL, the enhanced ASC-GSH cycle and content of sulfur-containing compounds might provide protective roles against oxidative stress in O. sativa roots under N-limiting conditions. Quantitative real-time PCR (qRT-PCR) analysis indicated that 70% of the enzymes have a consistence between the gene expression pattern and the dynamic of enzyme activity in O. sativa leaves under different N supplies, whereas only 60% of the enzymes have a consistence in O. sativa roots. Our results suggested that the antioxidant system and sulfur metabolism take part in the response of N limiting condition in O. sativa, and this response was different between leaves and roots. Future work should focus on the responsive mechanisms underlying the metabolism of sulfur-containing compounds in O. sativa under nutrient deficient especially N-limiting conditions.

Multiple Biomarker Responses in Aegla castro Exposed to Copper: A Laboratory Approach.

Although some biomarkers have already been determined in aeglids collected in the field, data from laboratory exposures are scarce. To our knowledge, no studies have investigated oxidative stress biomarkers in aeglids exposed to metals in the laboratory, or performed hemocyte counts and the comet assay using gill and hepatopancreas of aeglids. Thus, we investigated the effects of acute Cu exposure on intermolt males of Aegla castro, collected from a reference stream, acclimated for 6days in the laboratory, and then exposed to 11μgL-1 of dissolved Cu (Cu 11) or only to water (CTR), for 24h. Gill and hepatopancreas samples were used to determine Cu accumulation, DNA damage, and metallothionein content (MT), while hemolymph samples were used to determine Cu accumulation, DNA damage, and hemocyte counts. Muscle samples were used to determine Cu accumulation and acetylcholinesterase activity (AChE). Non-protein thiol content (NPSH), catalase (CAT), glutathione S-transferase activities (GST), lipoperoxidation (LPO), and protein carbonylation content (PCC) were measured only in the hepatopancreas. Aegla castro exposed to Cu accumulated this metal in gills and activated detoxification mechanisms, through increased MT content in the gill, and showed an immune response, evidenced by an increase in hyaline hemocytes. Therefore, gill and hemocytes appear to have a protective role in preventing the transport and bioavailability of Cu through the body. On the other hand, we observed a decrease in MT content in the hepatopancreas of crabs exposed to Cu, suggesting the excretion of MT in association with Cu bound to the sulfhydryl groups of this protein.

Hormetic responses to cadmium exposure in wheat seedlings: insights into morphological, physiological, and biochemical adaptations.

Cadmium is commonly recognized as toxic to plant growth, low-level Cd has promoting effects on growth performance, which is so-called hormesis. Although Cd toxicity in wheat has been widely investigated, knowledge of growth response to a broad range of Cd concentrations, especially extremely low concentrations, is still unknown. In this study, the morphological, physiological, and biochemical performance of wheat seedlings to a wide range of Cd concentrations (0-100 µΜ) were explored. Low Cd treatment (0.1-0.5µM) improved wheat biomass and root development by enhancing the photosynthetic system and antioxidant system ability. Photosynthetic rate (Pn) was improved by 5.72% under lower Cd treatment (1 µΜ), but inhibited by 6.05-49.85% from 5 to 100 µΜ. Excessive Cd accumulation induced oxidative injury manifesting higher MDA content, resulting in lower photosynthetic efficiency, stunted growth, and reduction of biomass. Further, the contents of ascorbate, glutathione, non-protein thiols, and phytochelatins were improved under 5-100 µΜ Cd treatment. The ascorbate peroxidase activity in the leaf showed a hormetic dose-response characteristic. Correlation analysis and partial least squares (PLS) results indicated that antioxidant enzymes and metabolites were closely correlated with Cd tolerance and accumulation. The results of the element network, correlation analysis, and PLS showed a crucial role for exogenous Cd levels in K, Fe, Cu, and Mn uptake and accumulation. These results provided a deeper understanding of the hormetic effect of Cd in wheat, which would be beneficial for improving the quality of hazard and risk assessments.

Mentha arvensis oil exhibits repellent acute toxic and antioxidant activities in Nauphoeta cinerea

Mentha arvensis is an herbaceous plant commonly known as peppermint or Japanese mint. This study investigated the toxic potential and repellent efficacy of M. arvensis essential oil (MaEO) at varying concentrations (15.625–250 mg/mL) in Nauphoeta cinerea, along with its impact on biochemical parameters in N. cinerea. The potential of the major compounds as a new analgesic target was investigated using molecular docking. The essential oil was analyzed by gas Chromatography–mass spectrometry (GC–MS) and the toxic potential, repellent property, and changes in lipid peroxidation (LPO) levels were evaluated as markers of oxidative stress. GC–MS results revealed that the main components were oxygenated monoterpenes such as menthol (71.31%), mentone (13.34%) and isomentone (5.35%). MaEO significantly reduced lipid peroxidation (LPO), the levels of non-protein thiols and iron(II) at the concentration of 125 mg/mL in N. cinerea. Furthermore, the major components, l-(−)-Menthol and menthone demonstrated high gastrointestinal absorption and high affinity with the target protein, suggesting possible links that contribute to the analgesic effect of MaEO.

Efficiency of metal(loid) phytostabilization by white lupin (Lupinus albus L.), common vetch (Vicia sativa L.), and buckwheat (Fagopyrum esculentum Moench).

Erosion and leaching of metal(loid)s from contaminated sites can spread pollution to adjacent ecosystems and be a source of toxicity for living organisms. Phytostabilization consists of selecting plant species accumulating little or no metal(loid)s in aerial parts to establish a vegetation cover and thus to stabilize the contaminants in the soil. Seeds of white lupin, common vetch, and buckwheat were sown in greenhouse on soils from former French mines (Pontgibaud and Vaulry) contaminated with metal(loid)s including high concentrations of As and Pb (772 to 1064 and 121 to 12,340mgkg-1, respectively). After 3weeks of exposure, the growth of white lupin was less affected than that of the 2 other species probably because metal(loid) concentrations in roots and aerial parts of lupins were lower (5-20 times less Pb in lupin leaves on Pontgibaud soil and 5-10 times less As in lupin leaves on Vaulry soil than in vetch and buckwheat). To limit oxidation and/or scavenge metal(loid)s, white lupin increased the content of proline and total phenolic compounds (TPC) in leaves and roots by a factor 2 whereas buckwheat stimulated the production of TPC by a factor 1.5-2, and non-protein thiols (NPT) by factors around 1.75 in leaves and 6-12 in roots. Vetch accumulated more proline than white lupin but less NPT than buckwheat and less TPC than the 2 other plant species. The level of oxidation was however higher than in control plants for the 3 species indicating that defense mechanisms were not completely effective. Overall, our results showed that white lupin was the best species for phytostabilization but amendments should be tested to improve its tolerance to metal(loid)s.

Averrhoa carambola Leaf Extract Induces Apoptosis-Like Death with Increased ROS Generation in Leishmania donovani.

The parasitic disease leishmaniasis is responsible for high mortality and morbidity rates worldwide. The visceral form is the most severe form of leishmaniasis (or leishmaniosis), which is caused predominantly by Leishmania donovani. Currently, clinically recommended antileishmanial drugs are not convenient because of several medical complications and resistance issues. Phytocompounds are the best candidates in this regard. The present study aimed to evaluate the antileishmanial activity of Averrhoa carambola leaf extract. The antipromastigote activity and cytotoxicity were assessed using the MTT assay. Morphological distortions were determined using phase contrast microscopy and scanning electron microscopy (SEM). Reactive oxygen species (ROS) production, nonprotein thiol depletion and apoptotic death in promastigotes were determined via flow cytometry. UV-visible spectroscopy and energy dispersive X-ray (EDX) spectroscopy was performed for elemental analysis. Fourier-transform infrared spectroscopy (FTIR) and liquid chromatography‒mass spectrometry (LCMS) were used to characterize the phytocomponent(s) present in the extract. The chloroform extract of Averrhoa carambola leaf (ACCEX) (IC50 = 50.76 ± 1.7µg/mL) exhibited the highest activity, followed by the ethyl acetate, hexane, and methanol extracts. ACCEX has also exhibited lower toxicity towards host macrophages. ACCEX also induced morphological distortions in promastigotes, with significant generation of ROS and the concomitant apoptosis initiation followed by a decrease in the nonprotein thiol level. The major phytometabolites present in ACCEX were identified from the National Institute of Standards and Technology (NIST) database and from a literature review. This study suggested that Averrhoa carambola leaf extracts are rich in some classes of biologically active phytocompounds and exhibit good antileishmanial activity.

Role of SbNRT1.1B in cadmium accumulation is attributed to nitrate uptake and glutathione-dependent phytochelatins biosynthesis

Phytoremediation of cadmium (Cd)-polluted soil by using sweet sorghum displays a tremendous potential as it is a fast-growing, high biomass and Cd tolerant energy plant. Previous study has demonstrated SbNRT1.1B expression change is in accordance with enhanced Cd accumulation by external nitrate supply in sweet sorghum. Nevertheless, underlying mechanism of SbNRT1.1B response to Cd stress is still elusive. SbNRT1.1B exhibited a positive response to Cd stress in sweet sorghum. Overexpressing SbNRT1.1B increased primary root length, shoot fresh weight, nitrate and chlorophyll concentrations compared with Col-0 under Cd stress, while complementary SbNRT1.1B rescued these decreased values in mutant chl1–5. Cd concentrations in overexpressing SbNRT1.1B, complementary SbNRT1.1B and Col-0 lines were 3.2–4.1, 2.5–3.1 and 1.2–2.1 folds of that in chl1–5. Consistent with Cd concentrations, non-protein thiol (NPT), reduced glutathione (GSH) and phytochelatins (PCs) concentrations as well as the related genes expression levels showed the same trends under Cd stress. GSH biosynthesis inhibitor failed to reverse the patterns of GSH-dependent PCs concentrations changes in different lines, suggesting that SbNRT1.1B plays an upstream role in GSH-dependent PCs biosynthesis under Cd treatment. Altogether, SbNRT1.1B enhances nitrate concentrations contributing to increased chlorophyll concentrations and GSH-dependent PCs metabolites biosynthesis, thereby improving growth and Cd concentrations in plants.

Evaluation of interaction among arsenic and Brevibacterium sp. strain CS2 and its proteins profiling

In this study, Brevibacterium sp. strain CS2 was used to evaluate the mechanisms of arsenic interaction with the bacterium and its enzymatic and protein profiling under arsenic stress. The bacterium was capable to resist the arsenate 280 mM and arsenite 40 mM as per MIC. The whole genome, available on NCBI, was analyzed for genes associated with arsenic, which confirmed the genes for both arsenic oxidation (aioB) and arsenic reduction arsR, arsC, ACR3, and arsB. The sharpening and shifting of FTIR spectra in the ranges of 3278–2851 cm−1 are due to hydroxyl and amide stretching. SEM analysis showed no significant changes in morphology in arsenic stress while EDX analysis proved the arsenite interaction by showing arsenic peaks in the graph. Both glutathione and non-protein thiol showed different responses in the absence and presence of arsenic stress. Protein bands such as 25, 30, 32, 37, 42, 48, and 100 kDa were expressed more in arsenic-treated samples as compared to the control one. The presence of arsenic oxidizing genes, the ability to resist arsenic, and the varied response of enzymes and proteins in arsenic stress make the bacterium a suitable agent for arsenic eradication from contaminated sites.

Protective Role of Polyethylene Glycol Towards the Damaging Effects of Cadmium.

This study aimed to evaluate the role of drought-induced changes in the effects of cadmium (Cd) in plants. Cd is the most hazardous and important environmental pollutant. Water deficit is the most common environmental stress encountered by plants and affects most of the plant functions. The present study assessed the effect of Cd and water deficit on Capsicum frutescens seedlings in single and combined treatments. The seedlings of Capsicum were grown in a hydroponic solution and treated with Cd. The seedlings were subjected to water deficit with the help of polyethylene glycol (PEG). The other set of seedlings was treated with combined Cd + PEG. In the absence of PEG, maximum Cd accumulation was observed. The root and shoot growth of the seedlings were affected under all treatments with maximum inhibition in Cd. Pigment, protein and sugar contents and nitrate reductase activity decreased significantly in all treatments, while proline content increased. Induction of oxidative damage occurred through the formation of free radicals which caused alteration in electrolyte leakage, lipid peroxidation and activities of antioxidant enzymes, viz. superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and non-enzymatic non-protein thiol content and ascorbic acid in the stressed seedlings. Water deficit buttressed the toxic effect of Cd on chilli seedlings.