Chromium toxicity in plants: consequences on growth, chromosomal behavior and mineral nutrient status

Chromium (Cr) is a heavy metal of commercial importance; thus, significant amounts are released in wastewaters. The mobility and distribution of metals in the environment is related not only to their concentration but also to their availability in the environment. Most chromium (Cr) exists in oxidation states ranging from 0 to VI in soils but the most stable and common forms are Cr(0), Cr(III), and Cr(VI) species. Cr can have positive and negative effects on health, according to the dose, exposure time, and its oxidation state. Its behavior in soil, its soil-plant transfer and accumulation in different plant parts vary with its chemical form, plant type and soil physicochemical properties. Soil microbial community plays a key role in governing Cr speciation and behavior in soil. A number of factors have been identified to influence Cr toxicity on activated sludge, such as, pH, biomass concentration, presence of organic substances or other heavy metals, acclimation process, exposure time, etc. Inside plants, Cr provokes numerous deleterious effects to several physiological, morphological, and biochemical processes. Cr induces phytotoxicity by interfering plant growth, nutrient uptake and photosynthesis, inducing enhanced generation of reactive oxygen species, causing lipid peroxidation and altering the antioxidant activities. The present review describes the consequences of Cr toxicity on plants, including morphological, physiological and ultrastructural changes. This review also provides the basic concepts of Cr translocation and interaction with other essential macro-and microelements. Moreover, based on the available literature and current research scenario, this review suggests some possible management and remediation strategies to alleviate Cr toxicity and contamination in soil. It also provides valuable knowledge for further studies towards enhancement of soil phytoremediation and crops improvement. Therefore, there is a dire need to monitor biogeochemical behavior of Cr in soil-plant system

Effects of a high-dose 24-h infusion of tranexamic acid on death and thromboembolic events in patients with acute gastrointestinal bleeding (HALT-IT): an international randomised, double-blind, placebo-controlled trial

Background: Tranexamic acid reduces surgical bleeding and reduces death due to bleeding in patients with trauma. Meta-analyses of small trials show that tranexamic acid might decrease deaths from gastrointestinal bleeding. We aimed to assess the effects of tranexamic acid in patients with gastrointestinal bleeding. Methods: We did an international, multicentre, randomised, placebo-controlled trial in 164 hospitals in 15 countries. Patients were enrolled if the responsible clinician was uncertain whether to use tranexamic acid, were aged above the minimum age considered an adult in their country (either aged 16 years and older or aged 18 years and older), and had significant (defined as at risk of bleeding to death) upper or lower gastrointestinal bleeding. Patients were randomly assigned by selection of a numbered treatment pack from a box containing eight packs that were identical apart from the pack number. Patients received either a loading dose of 1 g tranexamic acid, which was added to 100 mL infusion bag of 0·9% sodium chloride and infused by slow intravenous injection over 10 min, followed by a maintenance dose of 3 g tranexamic acid added to 1 L of any isotonic intravenous solution and infused at 125 mg/h for 24 h, or placebo (sodium chloride 0·9%). Patients, caregivers, and those assessing outcomes were masked to allocation. The primary outcome was death due to bleeding within 5 days of randomisation; analysis excluded patients who received neither dose of the allocated treatment and those for whom outcome data on death were unavailable. This trial was registered with Current Controlled Trials, ISRCTN11225767, and ClinicalTrials.gov, NCT01658124. Findings: Between July 4, 2013, and June 21, 2019, we randomly allocated 12 009 patients to receive tranexamic acid (5994, 49·9%) or matching placebo (6015, 50·1%), of whom 11 952 (99·5%) received the first dose of the allocated treatment. Death due to bleeding within 5 days of randomisation occurred in 222 (4%) of 5956 patients in the tranexamic acid group and in 226 (4%) of 5981 patients in the placebo group (risk ratio [RR] 0·99, 95% CI 0·82–1·18). Arterial thromboembolic events (myocardial infarction or stroke) were similar in the tranexamic acid group and placebo group (42 [0·7%] of 5952 vs 46 [0·8%] of 5977; 0·92; 0·60 to 1·39). Venous thromboembolic events (deep vein thrombosis or pulmonary embolism) were higher in tranexamic acid group than in the placebo group (48 [0·8%] of 5952 vs 26 [0·4%] of 5977; RR 1·85; 95% CI 1·15 to 2·98). Interpretation: We found that tranexamic acid did not reduce death from gastrointestinal bleeding. On the basis of our results, tranexamic acid should not be used for the treatment of gastrointestinal bleeding outside the context of a randomised trial

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Phenanthrene Mitigates Cadmium Toxicity in Earthworms <i>Eisenia fetida</i> (Epigeic Specie) and <i>Aporrectodea caliginosa</i> (Endogeic Specie) in Soil

In classical toxicology studies, the interaction of combined doses of chemicals with dissimilar modes of toxic action in soil is complex and depending on the end point investigated and the experimental protocol employed. This study was used to examine the interactive effect of phenanthrene and Cadmium on two ecologically different species of earthworms; Eisenia. fetida and Aporrectodea. caliginosa. This interactive effect was scrutinized by using the acute toxicity test with the concentrations of 2.51 mg kg&#8722;1 and 3.74 mg kg&#8722;1, respectively, being lethal for 50% of E. fetida and A. caliginosa. The results showed that in the mixture treatment, phenanthrene at 5, 10, 15 and 20 mg kg&#8722;1 significantly mitigated both earthworms species mortality and body-mass loss. Moreover, the factor of Cd accumulated in E. fetida and A. caliginosa tissues was significantly decreased by about 12% and 16%, respectively. Linear regression correlation coefficient revealed that the reduction of both earthworm species mortality was negatively and significantly correlated (r2 = 0.98 &#177; 0.40 and 1 &#177; 3.9 p &lt; 0.001) with phenanthrene concentration in soil. However, over 20 mg kg&#8722;1 of phenanthrene, both organisms mortality rate increased again, as was the Bioaccumulation factor of phenanthrene. Thus, this study proposes that the antagonistical effect of phenanthrene on Cd at a degree of concentration can be used to mitigate Cd effect on soil living organisms. However, as an implication of these results, the interpretation of standardized toxicity bioassays, including whole effluent toxicity tests and single-compound toxicity tests, should be performed with caution. In addition, risk assessment protocols for environment pollution by a mixture of metals and polycyclic aromatic hydrocarbons should include robust methods that can detect possible interactive effects between contaminants to optimize environmental protection

Modified Rice Straw Enhanced Cadmium (II) Immobilization in Soil and Promoted the Degradation of Phenanthrene in Co-Contaminated Soil

Very limited information is available about heavy metal-polycyclic aromatic hydrocarbons (PAHs) depollution involving the modified natural material in soil. Using phenanthrene and cadmium (Cd) as model, this study investigated the effect(s) of modified rice straw by a NaOH solution and on PAHs, heavy metal availability, and their interactions. Treatment included chemical contaminant with/without modified/unmodified rice straw. Fourier Transform Infrared (FTIR) analysis revealed that certain functional groups including anionic matters groups, which can a complex with Cd2+, were exposed on the modified rice straw surfaces. Therefore, Cd concentration was significantly reduced by about 60%, 57%, 62.5 %, and, 64% in the root, shoot, CaCl2, diethylenetriaminepentaacetic acid (DTPA), and extractable Cd, respectively. Subsequently, the prediction of the functional profile of the soil metagenome using Clusters Orthologous Groups (COGs) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) database revealed that the significantly changed individual COGs belonged to the carbohydrate metabolism, ion transports, and signaling (including cytochrome P450s) categories. This indicated that ion transports might be involved in Cd management, while carbohydrate metabolism, including bisphenol, benzoate, ethylbenzene degradation, and cytochrome P450s, were rather involved in phenanthrene metabolism. The exposed functional group might serve as an external substrate, and P450s might serve as a catalyst to activate and initiate phenanthrene metabolism process. These finding offer confirmation that modified straw could promote the reduction of heavy metal and the degradation of PAHs in soil

Can Selenium and Molybdenum Restrain Cadmium Toxicity to Pollen Grains in Brassica napus?

Cadmium (Cd) is highly toxic, even at very low concentrations, to both animals and plants. Pollen is extremely sensitive to heavy metal pollutants; however, less attention has been paid to the protection of this vital part under heavy metal stress. A pot experiment was designed to investigate the effect of foliar application of Se (1 mg/L) and Mo (0.3 mg/L) either alone or in combination on their absorption, translocation, and their impact on Cd uptake and its further distribution in Brassica napus, as well as the impact of these fertilizers on the pollen grains morphology, viability, and germination rate in B. napus under Cd stress. Foliar application of either Se or Mo could counteract Cd toxicity and increase the plant biomass, while combined application of Se and Mo solutions on B. napus has no significant promotional effect on plant root and stem, but reduces the seeds&rsquo; weight by 10&ndash;11%. Se and Mo have decreased the accumulated Cd in seeds by 6.8% and 9.7%, respectively. Microscopic studies, SEM, and pollen viability tests demonstrated that pollen grains could be negatively affected by Cd, thus disturbing the plant fertility. Se and Mo foliar application could reduce the toxic symptoms in pollen grains when the one or the other was sprayed alone on plants. In an in vitro pollen germination test, 500 &mu;M Cd stress could strongly inhibit the pollen germination rate to less than 2.5%, however, when Se (10 &mu;M) or Mo (1.0 &mu;M) was added to the germination medium, the rate increased, reaching 66.2% and 39.4%, respectively. At the molecular level, Se and Mo could greatly affect the expression levels of some genes related to Cd uptake by roots (IRT1), Cd transport (HMA2 and HMA4), Cd sequestration in plant vacuoles (HMA3), and the final Cd distribution in plant tissue at the physiological level (PCS1)

Deciphering Plantago ovata Forsk Leaf Extract Mediated Distinct Germination, Growth and Physio-Biochemical Improvements under Water Stress in Maize (Zea mays L.) at Early Growth Stage

Use of Plantago ovata Forsk leaf (also known as blond plantain or isabgol) extract is a novel approach for ameliorating water stress in various agronomic crops such as maize (Zea mays L.). To examine the potential roles of P. ovata extract (0, 20 and 40%) in increasing seed germination, plant growth, photosynthetic measurements, stomatal properties, oxidative stress and antioxidant response, ions uptake and the relationship between studied parameters, we investigated the impacts of its short-term seed priming on Z. mays L. elite cultivar “Cimmyt-Pak” under a control environment and a water deficit stress environment (induced by PEG). It was evident that water deficit stress conditions induced a negative impact on plant growth, stomatal properties and ion uptake in different organs of Z. mays. The decrease in growth-related attributes might be due to overproduction of oxidative stress biomarkers, i.e., malondialdehyde (MDA) contents, hydrogen peroxide (H2O2) initiation, and electrolyte leakage (%), which was also overcome by the enzymatic antioxidants, i.e., superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidants, which increased under the water stress environment. However, seed priming with P. ovata extract positively increased germination rate and growth profile, and protected photosynthetic apparatus and stomatal properties by decreasing oxidative stress indicators and increasing activities of antioxidant compounds. Our results also depicted that the optimum concentration of P. ovata extract for Z. mays seedlings under water stress conditions was 20%, while a further increase in P. ovata extract (40%) induced a non-significant negative impact on growth and biomass of Z. mays seedling. In addition, the effect was more promising on Z. mays seedlings when grown under controlled conditions. Here, we concluded that the understanding of the role of seed priming with P. ovata extract in the increment of growth-related attributes, photosynthetic apparatus (Pn, Gs, Ts and Ci) and nutrient uptake (Ca2+, Fe2+, P and Mg2+) introduces new possibilities for their effective use in water deficit stress environments and shows a promising foundation for Z. mays tolerance against water deficit stress conditions

Molybdenum-Induced Effects on Nitrogen Metabolism Enzymes and Elemental Profile of Winter Wheat (Triticum aestivum L.) Under Different Nitrogen Sources

Different nitrogen (N) sources have been reported to significantly affect the activities and expressions of N metabolism enzymes and mineral elements concentrations in crop plants. However, molybdenum-induced effects in winter wheat cultivars have still not been investigated under different N sources. Here, a hydroponic study was carried out to investigate these effects on two winter wheat cultivars (&lsquo;97003&rsquo; and &lsquo;97014&rsquo;) as Mo-efficient and Mo-inefficient, respectively, under different N sources (NO3&minus;, NH4NO3, and NH4+). The results revealed that the activities of nitrate reductase (NR) and nitrite reductase (NiR) followed the order of NH4NO3 &gt; NO3&minus; &gt; NH4+ sources, while glutamine synthetase (GS) and glutamate synthase (GOGAT) followed the order of NH4+ &gt; NH4NO3 &gt; NO3&minus; in both the wheat cultivars. However, Mo-induced effects in the activities and expressions of N metabolism enzymes under different N sources followed the order of NH4NO3 &gt; NO3&minus; &gt; NH4+ sources, indicating that Mo has more complementary effects towards nitrate nutrition than the sole ammonium source in winter wheat. Interestingly, under &minus;Mo-deprived conditions, cultivar &lsquo;97003&rsquo; recorded more pronounced alterations in Mo-dependent parameters than &lsquo;97014&rsquo; cultivar. Moreover, Mo application increased the proteins, amino acids, ammonium, and nitrite contents while concomitantly decreasing the nitrate contents in the same order of NH4NO3 &gt; NO3&minus; &gt; NH4+ sources that coincides with the Mo-induced N enzymes activities and expressions. The findings of the present study indicated that Mo plays a key role in regulating the N metabolism enzymes and assimilatory products under all the three N sources; however, the extent of complementation exists in the order of NH4NO3 &gt; NO3&minus; &gt; NH4+ sources in winter wheat. In addition, it was revealed that mineral elements profiles were mainly affected by different N sources, while Mo application generally had no significant effects on the mineral elements contents in the winter wheat leaves under different N sources

Role of Ferrous Sulfate (FeSO4) in Resistance to Cadmium Stress in Two Rice (Oryza sativa L.) Genotypes

The impact of heavy metal, i.e., cadmium (Cd), on the growth, photosynthetic pigments, gas exchange characteristics, oxidative stress biomarkers, and antioxidants machinery (enzymatic and non-enzymatic antioxidants), ions uptake, organic acids exudation, and ultra-structure of membranous bounded organelles of two rice (Oryza sativa L.) genotypes (Shan 63 and Lu 9803) were investigated with and without the exogenous application of ferrous sulfate (FeSO4). Two O. sativa genotypes were grown under different levels of CdCl2 [0 (no Cd), 50 and 100 &micro;M] and then treated with exogenously supplemented ferrous sulfate (FeSO4) [0 (no Fe), 50 and 100 &micro;M] for 21 days. The results revealed that Cd stress significantly (p &lt; 0.05) affected plant growth and biomass, photosynthetic pigments, gas exchange characteristics, affected antioxidant machinery, sugar contents, and ions uptake/accumulation, and destroy the ultra-structure of many membranous bounded organelles. The findings also showed that Cd toxicity induces oxidative stress biomarkers, i.e., malondialdehyde (MDA) contents, hydrogen peroxide (H2O2) initiation, and electrolyte leakage (%), which was also manifested by increasing the enzymatic antioxidants, i.e., superoxidase dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) and non-enzymatic antioxidant compounds (phenolics, flavonoids, ascorbic acid, and anthocyanin) and organic acids exudation pattern in both O. sativa genotypes. At the same time, the results also elucidated that the O. sativa genotypes Lu 9803 are more tolerant to Cd stress than Shan 63. Although, results also illustrated that the exogenous application of ferrous sulfate (FeSO4) also decreased Cd toxicity in both O. sativa genotypes by increasing antioxidant capacity and thus improved the plant growth and biomass, photosynthetic pigments, gas exchange characteristics, and decrease oxidative stress in the roots and shoots of O. sativa genotypes. Here, we conclude that the exogenous supplementation of FeSO4 under short-term exposure of Cd stress significantly improved plant growth and biomass, photosynthetic pigments, gas exchange characteristics, regulate antioxidant defense system, and essential nutrients uptake and maintained the ultra-structure of membranous bounded organelles in O. sativa genotypes