Search

Cobalt (Co2+) is a beneficial microelement for plants but toxic to metabolism in higher amounts. This study determined the influence of sublethal Co2+ level (0.5 mM) on the growth of maize (Zea mays L.) hybrids; Hycorn 11 plus (Co2+ sensitive) and P-1429 (Co2+ tolerant) and its alleviation with foliar spray of pre-optimized levels of stress protective chemicals (SPCs), i.e., salicylic acid (SA, 0.5 mM), thiourea (TU, 1.0 mM), and ascorbic acid (AsA, 0.5 mM) applied at seedling, vegetative, and late vegetative stages. Plants were harvested at early vegetative, late vegetative, and silking stages. Co2+ stress caused a decrease in shoot and root length, dry weight, leaf area, and culm diameter, reduced the activities of enzymatic antioxidants and concentrations of AsA and soluble phenolics more in root than shoot, but P-1429 was more tolerant of Co2+ than Hycorn 11 plus. SPCs spray alleviated oxidative damage by enhancing the antioxidant activity, AsA and soluble phenolics, sulfate-S and nitrate–N contents, which were significantly increased in roots than in shoots; P-1429 displayed better response than Hycorn 11 plus. Principal component analysis and correlation matrix revealed the profound roles of SPCs spray in improving Co2+ resistance in root leading to robust growth of hybrids. AsA was highly promising in reducing Co2+ toxicity while vegetative and silking stages were more sensitive. Results revealed that after translocation to root, the foliar-applied SPCs had individualistic modes of action in mitigating Co2+ toxicity on roots. In crux, the metabolism and phloem transport of the SPCs from shoot to root are plausible mechanism for Co2+ tolerance in maize hybrids. [ABSTRACT FROM AUTHOR]

The use of wastewater in irrigation weakens the beneficial properties of the soil and leads to a threat to food safety standards. The present research was designed to explore the cobalt toxicity associated with the ingestion of wastewater irrigated wheat. Wheat plants of five different varieties were collected from 7 different sites of Punjab, Pakistan, which were irrigated with three different sources of water. The sampling was done in two cropping years. The cobalt values in water, soil and wheat samples (root, shoot, grain) ranged from 0.46 to 1.24 mg/l, 0.15 to 1.20, 0.29 to 1.30, 0.08 to 0.76 and 0.12 to 0.57 mg/kg, respectively. All the water samples showed high cobalt concentration than the maximum permissible value. However, all the soil and wheat plant samples were found within the maximum allowable range. The high cobalt concentration in irrigating water showed that the continuous usage of such type of water may lead to cobalt toxicity in living organisms with the passage of time and may results in severe health risks. [ABSTRACT FROM AUTHOR]

Excessive cobalt exposure has been shown to induce various adverse health effects in animal and human toxicity studies. However, the relationships between cobalt exposure and obesity, insulin resistance, and metabolic-related disorders are rarely studied in epidemiological studies. This study aimed to explore the dose–response relationships between urinary cobalt concentrations and obesity, insulin resistance, and metabolic-related disorders. Adult participants (≥20 years) from the 2005 to 2018 National Health and Nutrition Examination Survey were included. Restricted cubic splines and the log-binomial regression were adopted. Multivariate adjusted prevalence ratios (95% confidence intervals) comparing extreme quartiles of urinary cobalt concentrations were 1.43 (1.29–1.57) for obesity, 1.43 (1.10–1.86) for insulin resistance, 1.21 (1.09–1.34) for metabolic syndrome, 1.16 (1.10–1.23) for elevated waist circumference, 1.20 (1.09–1.33) for elevated triglycerides, 1.14 (1.01–1.29) for reduced high-density lipoprotein cholesterol (HDL-C), 1.06 (0.98–1.15) for elevated blood pressure, and 0.91 (0.79–1.06) for elevated fasting glucose, respectively. Results from the restricted cubic splines showed that an initial steep increase in risk was followed by a weaker increase in risk or a platform beyond 1.0 µg/L for obesity (prevalence ratio (95% confidence interval): 1.41 (1.29–1.55)), insulin resistance (1.33 (1.07–1.65)), metabolic syndrome (1.18 (1.11–1.31)), elevated waist circumference (1.18 (1.11–1.25)), elevated triglycerides (1.21 (1.11–1.33)), and reduced HDL-C (1.15 (1.01–1.30)), respectively. In conclusion, the prevalence of obesity, insulin resistance, metabolic syndrome, elevated waist circumference, elevated triglycerides, and reduced HDL-C progressively increased with increasing urinary cobalt concentrations. The above associations are non-linear and there is not a "safe threshold" below which there are no toxic effects of cobalt. [ABSTRACT FROM AUTHOR]

Cobalt exposure has adverse health effects on the cardiovascular system in occupational and laboratory studies, but these effects have not been assessed in the general population. We aimed to determine whether serum cobalt levels had relationship with the prevalence of cardiovascular disease (CVD) in the general population. Using data from the National Health and Nutrition Examination Survey (NHANES) (2015–2016), we performed the cross-sectional study. We analyzed the baseline characteristics of 3389 participants (1623 men and 1766 women). Generalized linear models and restricted cubic spline plots curve were undertaken to elucidate the relationship. Stratified subgroup analysis was tested to exclude interaction between different variates and cobalt. Our results showed that the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for CVD prevalence across the quartiles of cobalt were 0.94 (0.67, 1.30), 1.55 (1.15, 2.10), and 1.74 (1.28, 2.35) compared with lowest quartile. The restricted cubic spline curve also suggested nonlinear and positive association between cobalt and CVD (P for nonlinearity = 0.007). In summary, our cross-sectional results verify that higher cobalt levels are associated with a higher prevalence of cardiovascular disease. [ABSTRACT FROM AUTHOR]

Excessive doses of toxic metals such as cobalt may cause detrimental hazards to exposed organisms. Six groups of onion bulbs were formed to investigate the therapeutic effects of grape seed extract (GSE) against cobalt(II) nitrate (Co(NO3)2) exposure in Allium cepa L. root tips. Control group was irrigated with tap water, while the latter groups were exposed to 150 mg/L GSE, 300 mg/L GSE, 5.5 ppm Co(NO3)2, 5.5 ppm Co(NO3)2 + 150 mg/L GSE and 5.5 ppm Co(NO3)2 + 300 mg/L GSE, respectively. Co(NO3)2 treatment seriously inhibited the root growth, germination and weight gain of the bulbs. Mitotic index was significantly decreased, whereas the chromosomal aberrations and micronuclei incidence exhibited a remarkable increase. In addition, Co(NO3)2 induced a variety of anatomical disorders in onion roots. Lipid peroxidation levels of the cellular membranes were assessed measuring the malondialdehyde content (MDA). MDA amount in Co(NO3)2-treated group reached the highest level among all groups. Co(NO3)2 treatment enhanced the activity of superoxide dismutase and catalase. The addition of GSE to Co(NO3)2 solution substantially suppressed the negative effects of Co(NO3)2 in a dose-dependent manner by strengthening the antioxidant defence system and reducing the cytotoxicity. Moreover, there was a significant recovery in growth parameters following the grape seed addition to Co(NO3)2. GSE had a remarkable reduction in genotoxicity when treated as a mixture with Co(NO3)2. Overall data obtained from this investigation proved that GSE, as a promising functional by-product, had a protective effect on Allium cepa L. against the toxic effects of Co(NO3)2. [ABSTRACT FROM AUTHOR]

Cobalt (Co) is widely used in many industrial fields such as batteries and paints. Cobalt, a dangerous heavy metal, can be found in high concentrations in natural and human habitats. Although cobalt is an important micronutrient, it is toxic to living organisms when exposed to high amounts. Carob (Ceratonia siliqua L.) is a tree native to The Mediterranean region. Carob bean, which has high nutritional and economic value, is used against cardiovascular and gastrointestinal diseases. In addition, the antioxidant properties of carob are gaining importance in recent years. In this study, the protective effects of carob extract against the toxicity of cobalt on Allium cepa L. were investigated. For this purpose, 150 mg/L and 300 mg/L carob extract solutions and 5.5 mg/kg cobalt solutions were applied to A. cepa L. bulbs. Root emergence, weight gain, root elongation, and mitotic index (MI) decreased, while the frequency of chromosomal abnormalities (CAs) and micronucleus (MN) increased as a result of Co application. Furthermore, Co treatment triggered a noticeable rise in the activities of superoxide dismutase (SOD) and catalase (CAT) enzymes as well as the malondialdehyde (MDA) amount and the abnormalities in the meristematic cells. On the other hand, applications of carob extracts mitigated cobalt-induced damages in a dose-dependent manner in all parameters. Therefore, the current study showed that the strong preventive potential of carob extract against phytotoxicity and genotoxicity is caused by Co in a model plant. The protective effects of carob extract on Co-induced toxicity were demonstrated for the first time in terms of reducing genotoxicity and oxidative stress response. [ABSTRACT FROM AUTHOR]