Search

The present study investigated the bioaccumulation and translocation of mercury (Hg) and chromium (Cr) in Yunyan 87 flue-cured tobacco (Nicotiana tabacum) and assessed the influence of soil pH on the metal uptake by plant organs at the field scale. The study was conducted in 4 different regions selected from Sichuan Province, China: Guangyuan, Luzhou, Panzhihua, and Yibin. The results revealed that Hg highly contaminated Yibin soils at 0.29 mg kg−1 and by Cr at 147 mg kg-1, which is above the permissible limit. The levels of Hg in tobacco plant organs were predominantly in the order of leaves > root > stem. The overall trend for Cr contents in tobacco organs was in the order of root > leaves > stem. The results of an index of bioaccumulation (IBA) and translocation factor (TF) showed that the values observed in Panzhihua and Guangyuan tobacco leaves were generally higher, despite the low levels of soil contamination. The linear mixed model (LMM) demonstrated that the log of Hg IBA in tobacco organs was likely to decrease with soil pH increase, whereas the log of Cr IBA only decreased in the root but gradually increased in the aerial parts with soil pH increase. The total random variation in the log of metals' IBA due to regions indicated that for Hg, 33.42% of the variation was explained by regional differences, while for Cr, only 13% was accounted. The results suggested that Yibin and Luzhou need to correct the soil acidity if they are set to reduce Hg contamination in tobacco-growing soils. Guangyuan and Panzhihua need efforts to keep the soil pH on track to avoid high contamination levels, and effective measures of soil nutrients supply are required to produce high tobacco leaf quality free from heavy metal content. The findings of this study may be used to ascertain regional differences in heavy metals, particularly Hg and Cr uptake by tobacco plant organs, and to prevent the cultivation areas contamination through soil pH monitoring. [ABSTRACT FROM AUTHOR]

Numerous studies found intestinal microbiota alterations which are thought to affect the development of various diseases through the production of gut-derived metabolites. However, the specific metabolites and their pathophysiological contribution to cardiac hypertrophy or heart failure progression still remain unclear. N,N,N-trimethyl-5-aminovaleric acid (TMAVA), derived from trimethyllysine through the gut microbiota, was elevated with gradually increased risk of cardiac mortality and transplantation in a prospective heart failure cohort (n = 1647). TMAVA treatment aggravated cardiac hypertrophy and dysfunction in high-fat diet-fed mice. Decreased fatty acid oxidation (FAO) is a hallmark of metabolic reprogramming in the diseased heart and contributes to impaired myocardial energetics and contractile dysfunction. Proteomics uncovered that TMAVA disturbed cardiac energy metabolism, leading to inhibition of FAO and myocardial lipid accumulation. TMAVA treatment altered mitochondrial ultrastructure, respiration and FAO and inhibited carnitine metabolism. Mice with γ-butyrobetaine hydroxylase (BBOX) deficiency displayed a similar cardiac hypertrophy phenotype, indicating that TMAVA functions through BBOX. Finally, exogenous carnitine supplementation reversed TMAVA induced cardiac hypertrophy. These data suggest that the gut microbiota-derived TMAVA is a key determinant for the development of cardiac hypertrophy through inhibition of carnitine synthesis and subsequent FAO. Intestinal microbiota alterations may affect heart function through the production of gut-derived metabolites. Here the authors found that gut microbiota-derived TMAVA is a key determinant for the development of cardiac hypertrophy through inhibition of carnitine synthesis and subsequent fatty acid oxidation. [ABSTRACT FROM AUTHOR]

The association among plasma trimethylamine-N-oxide (TMAO), FMO3 polymorphisms, and chronic heart failure (CHF) remains to be elucidated. TMAO is a microbiota-dependent metabolite from dietary choline and carnitine. A prospective study was performed including 955 consecutively diagnosed CHF patients with reduced ejection fraction, with the longest follow-up of 7 years. The concentrations of plasma TMAO and its precursors, namely, choline and carnitine, were determined by liquid chromatography-mass spectrometry, and the FMO3 E158K polymorphisms (rs2266782) were genotyped. The top tertile of plasma TMAO was associated with a significant increment in hazard ratio (HR) for the composite outcome of cardiovascular death or heart transplantation (HR = 1.47, 95% CI = 1.13–1.91, P = 0.004) compared with the lowest tertile. After adjustments of the potential confounders, higher TMAO could still be used to predict the risk of the primary endpoint (adjusted HR = 1.33, 95% CI = 1.01–1.74, P = 0.039). This result was also obtained after further adjustment for carnitine (adjusted HR = 1.33, 95% CI = 1.01–1.74, P = 0.039). The FMO3 rs2266782 polymorphism was associated with the plasma TMAO concentrations in our cohort, and lower TMAO levels were found in the AA-genotype. Thus, higher plasma TMAO levels indicated increased risk of the composite outcome of cardiovascular death or heart transplantation independent of potential confounders, and the FMO3 AA-genotype in rs2266782 was related to lower plasma TMAO levels. [ABSTRACT FROM AUTHOR]

Vegetable gardens are increasingly common in urban areas and can provide numerous societal benefits; however, contamination with potential toxic elements (PTEs) due to urbanization and industrialization is cause for concern. The present study aimed to assess the source of contamination and pollution levels in urban garden soils, as well as the health risks for adults and children consuming vegetables grown in such environments. Various types of vegetable samples and their corresponding soils from 26 community gardens were collected throughout Chengdu City in southwestern China. The results showed that leafy vegetables, particularly lettuce leaves and Chinese cabbage, had relatively higher levels of Cd (0.04 mg/kg FW) and Pb (0.05 mg/kg FW), while higher levels of As (0.07 mg/kg FW), Cr (0.07 mg/kg FW), and Hg (0.003 mg/kg FW) were found in amaranths, tomatoes, and Houttuynia cordatas, respectively. The pollution indices revealed that the vegetable purplish soils were relatively more polluted by Cd and As, and the concentrations of these metals in vegetables were correlated with their concentrations in the soils. Principal component analysis grouped the PTEs in two dimensions that cumulatively explained 62.3% of their variation, and hierarchical clustering identified two distinct clusters indicating that Cr originated from a unique source. The health risk assessment revealed that exposure to As and Cd induced the greatest non-carcinogenic risk, whereas Cr was most likely to cause cancer risks. Furthermore, contaminated vegetable consumption was riskier for children than adults. The critical factors contributing to PTE contamination in vegetable gardens were determined to be vegetable species, total soil element content, soil pH, and soil organic matter content. Overall, Cr and As pollution present the greatest concern, and community health care services must enact more effective regulatory and preventative measures for urban gardens in terms of PTEs. [ABSTRACT FROM AUTHOR]

Trace element contamination in Chinese herbal medicines has been recognized as a potential health concern for consumers. To assess the health risk to the herb-consuming population, nine trace elements (Cu, Cd, Cr, Mo, Ni, Pb, Sr, Zn, and As) were investigated based on their concentrations in three common medicinal plants (Astragalus membranaceus, Codonopsis tangshen, and Paris polyphylla var. chinensis) and soils from unpolluted and polluted areas in the Sichuan Province, China. The results showed that the metal content differed significantly in medicinal plants and soils from unpolluted versus polluted areas. No significant differences in metal accumulation were observed for these CHMs grown in either unpolluted or polluted areas. Evaluation of the health risk index suggested that soil ingestion and medicated diet represented the dominant exposure routes, indicating that trace metal(loids) in local soil might pose potential risks through soil-food chain transfer. Hazard quotient values for AM (1.473) and CT (1.357) were higher than the standard value (HQ > 1), whereas the hazard indices for PC, AM, and CT were 13.18, 14.33, and 14.01 times higher than the safe limit (HI > 1) in the polluted area, indicating non-cancer-related health hazards. Ingestion of soil was responsible for 36.39 to 91.06% of the total cancer risk and medicated diet accounted for 6.35 to 62.71%, compared with inhalation and dermal contact, suggesting carcinogenic health risks in herbs from polluted soils. In this study, Pb showed relatively higher non-carcinogenic risks, while Cr and Ni posed the highest cancer risks. Therefore, we propose more effective measures, which should be considered for Cr, Ni, and Pb remediation in soil to reduce their pollution in the studied areas. [ABSTRACT FROM AUTHOR]