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Heavy metal stress affects crop growth and yields as wheat ( Triticum aestivum L.) growth and development are negatively affected under heavy metal stress. The study examined the effect of cobalt chloride (CoCl 2 ) stress on wheat growth and development. To alleviate this problem, a pot experiment was done to analyze the role of sulfur-rich thiourea (STU) in accelerating the defense system of wheat plants against cobalt toxicity. The experimental treatments were, i) Heavy metal stress (a) control and (b) Cobalt stress (300 µM), ii) STU foliar applications; (a) control and (b) 500 µM single dose was applied after seven days of stress, and iii) Wheat varieties (a) FSD-2008 and (b) Zincol-2016. The results revealed that cobalt stress decreased chlorophyll a by 10%, chlorophyll b by 16%, and carotenoids by 5% while foliar application of STU increased these photosynthetic pigments by 16%, 15%, and 15% respectively under stress conditions as in contrast to control. In addition, cobalt stress enhances hydrogen peroxide production by 11% and malondialdehyde (MDA) by 10%. In comparison, STU applications at 500 µM reduced the production of these reactive oxygen species by 5% and by 20% by up-regulating the activities of antioxidants. Results have revealed that the activities of SOD improved by 29%, POD by 25%, and CAT by 28% under Cobalt stress. Furthermore, the foliar application of STU significantly increased the accumulation of osmoprotectants as TSS was increased by 23% and proline was increased by 24% under cobalt stress. Among wheat varieties, FSD-2008 showed better adaptation under Cobalt stress by showing enhanced photosynthetic pigments and antioxidant activities compared to Zincol-2016. In conclusion, the foliar-applied STU can alleviate the negative impacts of Cobalt stress by improving plant physiological attributes and upregulating the antioxidant defense system in wheat. Graphical Abstract

Dinoflagellates grow in tight association with the bacterial community, which exert impacts on the physiology and ecology of both partners. However, the changes of associated-bacterial microbiome with the physiologies of the host dinoflagellate under specific heavy metals (HMs) stress remain largely unknown. In this study, we characterized the bacterial microbiome associated with the laboratory-cultured dinoflagellate Scrippsiella acuminata , a cosmopolitan bloom-forming species, under different cobalt concentrations, via high-throughput sequencing of 16 S rRNA gene amplicons. The sequencing of a total of 72 Libraries generated 6,047,695 reads which were classified into 31 phyla, 97 classes, 215 orders, 367 families, and 782 genera. We found that cobalt stress could greatly affect the growth of S. acuminata as well as the ASV diversity and community composition of the associated bacterial community. Significant dose-dependent changes in the bacterial community were detected, which were found to be closely correlated with some specific bacterial genera. Excessive cobalt exerted significantly inhibitory effects on microalgae growth-promoting bacteria ( Marinobacter , Roseobacter , Mameliella , Leifsonia , Roseovarius , and Stappia ). A notable increase in the relative abundance of HM-resistant bacteria with siderophore-producing capacity ( Alteromonas , Arthrobacter , Pseudoalteromonas , Brevundimonas , Staphylococcus , Microbacterium , and Bacillus ) and/or HM bio-removal potential ( Corynebacterium , Pseudomonas , Burkholderia , Rhodococcus , and Gemella ) was detected upon elevated cobalt concentrations, which potentially contributed to the cobalt stress alleviation of the dinoflagellate host. Our work provided deeper insights into the relationship between the associated-bacterial assemblage and dinoflagellate, and also broadened the current knowledge pertaining to the potential contributions of bacterial microbiome to the HM tolerance of host alga.

Cobalt (Co), while beneficial in trace amounts for biological systems, can severely impact plant growth at elevated levels in contaminated soils. This study investigated the physiological, biochemical and subcellular effects of Co toxicity on wheat ( Triticum aestivum L.) and evaluated, for the first time, the protective potential of Jania rubens extract. The algal extract analysis demonstrated its rich content of amino acids, minerals, phytohormones, and fatty acids. Wheat seedlings were subjected to cobalt chloride (150 mM) irrigation, which was previously primed with either water or J. rubens extract. Co stress significantly impaired growth by reducing water content and essential nutrients (K, Mg, and Fe), leading to a 42.42 and 23.8% decrease, respectively, in root and shoot biomasses, a 9% reduction in photosynthetic efficiency, visible chlorosis, and root thickening. Stress exposure also induced oxidative damage, shown by 67.1% increase in hydrogen peroxide and a 170.1% rise in malondialdehyde content, accompanied by membrane leakage and reduced antioxidant enzyme activities. Ultrastructural analysis confirmed morphophysiological and biochemical disruptions at the cellular level. Priming with J. rubens extract significantly alleviated these effects by enhancing nutrient uptake, increasing root and shoot biomasses by 78.94% and 58.33%, respectively, reducing oxidative damage and maintaining cellular homeostasis. It also preserved chloroplast structure, nucleus, and cell wall microtubules, maintaining overall cellular integrity and antioxidant efficiency. Our findings demonstrate that Jania rubens extract offers a promising and novel biogenic strategy for enhancing wheat resilience to cobalt contamination through its nutritional and antioxidant properties.

Brassinosteroids (BRs) play an essential role in regulating plant metabolic pathways that influence growth, development, and stress responses. However, their role in alleviating cobalt (Co) stress has not been extensively studied. This research aimed to assess the impact of exogenous BRs (0.1 µM) on maize subjected to Co stress (300 µM) in a hydroponic experiment. The results indicated that BR supplementation significantly decreased the accumulation of H2O2 by 17.79 and 16.66%, O2•− by 28.5 and 21.48%, and MDA by 37.5 and 37.9% in shoot and root, respectively, as compared to Co stress alone. Additionally, BRs enhanced endogenous levels of BRs (31.16%) and growth hormones (IAA 50.8%, JA 57.8%, GA 52.5%), and reduced Co contents by 26.3% in roots and 36.1% in shoots. BRs enhanced antioxidant enzyme activity both in the shoot and root, leading to reduced ROS levels as confirmed by laser scanning confocal microscopy. Furthermore, BRs increased phenols, flavonoids, and soluble sugars, and elevated total protein content. Observations from transmission electron microscopy indicated reduced ultrastructural damage in plants treated with BRs under Co stress. Taken together, this study highlights the role of BRs in alleviating Co stress in maize, demonstrating their efficiency in enhancing stress tolerance by modulating hormone levels and key metabolic processes.

To eliminate the damages of metal toxicity by reducing metal uptake by plants, organic amendments are useful. The use of carbon-rich materials known as biochar (BC) is a strong candidate to enhance the plant tolerance against stress conditions. The current study examined the effects of BC in wheat hydroponically grown treated with BC (1 and 3 g L −1 ) alone or in combination with cobalt (Co, 150 and 300 μM). Stress reduced the relative growth rate (RGR), relative water content (RWC), osmotic potential (Ψ Π ), and increased proline content (Pro). Besides, endogenous contents of Ca 2+ , K + , and Mn 2+ in leaves decreased under stress. In response to Co stress, a decline in the activities of peroxidase (POX), ascorbate peroxidase (APX), and glutathione reductase (GR) resulted in the induction of hydrogen peroxide (H 2 O 2 ) content. BC applied with stress decreased endogenous Co 2+ content and increased RGR, RWC, chlorophyll fluorescence and Pro content. Also, the activities of superoxide dismutase (SOD), catalase (CAT), APX and GR were induced and the ascorbate (AsA) and glutathione (GSH) pool and their redox state were maintained by BC application under stress condition. While, with the addition of BC, H 2 O 2 content and lipid peroxidation displayed remarkable decreased, the scavenging activity of hydroxyl radical (OH · ) increased as compared to Co stress-treated wheat plants. Besides, in wheat leaves, BC application triggered AsA-GSH pathway including activities of monodehydroascorbate reductase, dehydroascorbate reductase, and the contents of dehydroascorbate, GSH, and GSH/GSSG ratio. The presented results supported the view that biochar under stress could minimize the Co-induced oxidative damages through modulation of the growth, water status, photosynthetic apparatus, and antioxidant enzyme activity found in cellular compartments and ascorbate-glutathione cycle in wheat leaves.

The accumulation of excessive reactive oxygen species can exacerbate any injury of retinal tissue because free radicals can trigger lipid peroxidation, protein damage and DNA fragmentation. Increased oxidative stress is associated with the common pathological process of many eye diseases, such as glaucoma, diabetic retinopathy and ischemic optic neuropathy. Many studies have demonstrated that Lycium barbarum polysaccharides (LBP) protects against oxidative injury in numerous cells and tissues. For the model of hypoxia we used cultured retinal ganglion cells and induced hypoxia by incubating with 200 µM cobalt chloride (CoCl2) for 24 hours. To investigate the protective effect of LBP and its mechanism of action against oxidative stress injury, the retinal tissue was pretreated with 0.5 mg/mL LBP for 24 hours. The results of flow cytometric analysis showed LBP could effectively reduce the CoCl2-induced retinal ganglion cell apoptosis, inhibited the generation of reactive oxygen species and the reduction of mitochondrial membrane potential. These findings suggested that LBP could protect retinal ganglion cells from CoCl2-induced apoptosis by reducing mitochondrial membrane potential and reactive oxygen species.

Orientin is a flavonoid monomer. In recent years, its importance as a source of pharmacological active substance is growing rapidly due to its properties such as anti-myocardial ischemia, anti-apoptosis, anti-radiation, anti-tumor, and anti-aging. However, the neuroprotective effects of Orientin on stroke injury have not been comprehensively evaluated. The aim of the present study was thus to investigate the neuroprotective capacity and the potential mechanisms of Cyperus esculentus L. orientin (CLO) from Cyperus esculentus L. leaves against ischemia/reperfusion (I/R) injury using standard orientin as control. For in vitro studies, we treated HT22 cells with CoCl2 as an in vitro ischemic injury model. HT22 cells in the control group were treated with CoCl2. For in vivo studies, we used rat models of middle cerebral artery occlusion, and animals that received sham surgery were used as controls. We found that CLO protected CoCl2-induced HT22 cells against ischemia/reperfusion injury by lowering lipid peroxidation and reactive oxygen species formation as well as decreasing protein oxidation. However, CLO did not reduce the release of lactate dehydrogenase nor increase the activity of superoxide dismutase. Results showed that CLO could decrease neurological deficit score, attenuate brain water content, and reduce cerebral infarct volume, leading to neuroprotection during cerebral ischemia-reperfusion injury. Our studies indicate that CLO flavonoids can be taken as a natural antioxidant and bacteriostastic substance in food and pharmaceutical industry. The molecular mechanisms of CLO could be at least partially attributed to the antioxidant properties and subsequently inhibiting activation of casepase-3. All experimental procedures and protocols were approved on May 16, 2016 by the Experimental Animal Ethics Committee of Xinjiang Medical University of China (approval No. IACUC20160516-57).

Salinity stress ranks among the most prevalent stress globally, contributing to soil deterioration. Its negative impacts on crop productivity stem from mechanisms such as osmotic stress, ion toxicity, and oxidative stress, all of which impede plant growth and yield. The effect of cobalt with proline on mitigating salinity impact in radish plants is still unclear. That’s why the current study was conducted with aim to explore the impact of different levels of Co and proline on radish cultivated in salt affected soils. There were four levels of cobalt, i.e., (0, 10, 15 and 20 mg/L) applied as CoSO 4  and two levels of proline (0 and 0.25 mM), which were applied as foliar. The treatments were applied in a complete randomized design (CRD) with three replications. Results showed that 20 CoSO 4 with proline showed improvement in shoot length (∼ 20%), root length (∼ 23%), plant dry weight (∼ 19%), and plant fresh weight (∼ 41%) compared to control. The significant increase in chlorophyll, physiological and biochemical attributes of radish plants compared to the control confirms the efficacy of 20 CoSO 4 in conjunction with 10 mg/L proline for mitigating salinity stress. In conclusion, application of cobalt with proline can help to alleviate salinity stress in radish plants. However, multiple location experiments with various levels of cobalt and proline still needs in-depth investigations to validate the current findings.

Metals with nanocrystalline grains have ultrahigh strengths approaching two gigapascals. However, such extreme grain-boundary strengthening results in the loss of almost all tensile ductility, even when the metal has a face-centred-cubic structure—the most ductile of all crystal structures 1 – 3 . Here we demonstrate that nanocrystalline nickel–cobalt solid solutions, although still a face-centred-cubic single phase, show tensile strengths of about 2.3 gigapascals with a respectable ductility of about 16 per cent elongation to failure. This unusual combination of tensile strength and ductility is achieved by compositional undulation in a highly concentrated solid solution. The undulation renders the stacking fault energy and the lattice strains spatially varying over length scales in the range of one to ten nanometres, such that the motion of dislocations is thus significantly affected. The motion of dislocations becomes sluggish, promoting their interaction, interlocking and accumulation, despite the severely limited space inside the nanocrystalline grains. As a result, the flow stress is increased, and the dislocation storage is promoted at the same time, which increases the strain hardening and hence the ductility. Meanwhile, the segment detrapping along the dislocation line entails a small activation volume and hence an increased strain-rate sensitivity, which also stabilizes the tensile flow. As such, an undulating landscape resisting dislocation propagation provides a strengthening mechanism that preserves tensile ductility at high flow stresses. A nanocrystalline metallic alloy with ultrahigh tensile strength and good ductility is achieved by introducing compositional undulation in a highly concentrated solid solution.