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1.
Successive use of microorganisms to remove chromium from wastewater.
Elahi, A, Arooj, I, Bukhari, DA, Rehman, A
Applied microbiology and biotechnology. 2020;(9):3729-3743
Abstract
Heavy metal pollution is a direct consequence of the extensive utilization of heavy metals in various industrial processes. The persistence and nondegradability of heavy metals cause them to bioaccumulate in nature, and when they come in direct contact with the pristine environment, they not only contaminate it severely but also pose dire consequences to the health of all living forms on earth, including humans. Chromium (Cr) is one of the heavy metals which has been extensively used in various industrial processes such as mining, alloy manufacturing, tanning of hides and skins, pigment production, etc. However, it is regarded as a priority pollutant due to its highly toxic, teratogenic, mutagenic, and carcinogenic nature, and the U.S. Environmental Protection Agency (EPA) also categorized it into group "A" human carcinogen. In contrast to water-soluble hexavalent chromium (Cr6+), its reduced form, trivalent chromium (Cr3+), is relatively benign and readily precipitated at environmental pH. Thus, bioremediation of Cr6+ through microorganisms including bacteria, yeast, and algae provides a promising approach to decontaminate a metal-polluted environment. This review describes an overview of the microbial reduction of Cr6+, resistance mechanism, and the antioxidant profiling exhibited by these microorganisms when exposed to Cr6+. It also describes the pilot-scale study of the successive use of bacterial, fungal, and algal strains and the subsequent use of microbially purified water for the cultivation of plant growth. Multiple metal-resistant microorganisms are a good bioresource for green chemistry to eradicate environmental Cr6+. KEY POINTS • Hexavalent chromium (Cr6+) is highly toxic for living organisms including humans. • Microbial Cr resistance is mediated at the genetic, proteomic, and molecular levels. • Successive use of microorganisms is the best strategy to exterminate Cr6+from the environment.
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2.
Ascorbic acid is essential for inducing chromium (VI) toxicity tolerance in tomato roots.
Al-Huqail, AA, Ali, HM, Kushwaha, BK, Al-Huqail, AA, Singh, VP, Siddiqui, MH
Journal of biotechnology. 2020;:66-73
Abstract
Problem of chromium (Cr) pollution is of great scientific concern as it adversely affects crop productivity worldwide. Therefore, scientific efforts are being made to minimize Cr toxicity in crop plants by using various methods. Of these methods, use of certain chemicals like ascorbic acid (ASC), glutathione, proline, nutrients, etc. has shown promising results. Therefore, in this study, we have tested a role of ASC in regulating hexavalent chromium [Cr(VI)] toxicity in tomato roots. Chromium (VI) reduced length, dry weight, fitness and tissue density of roots due to enhanced cellular accumulation of Cr which leads to the cell death. Chromium (VI) also declined ASC pool and activity of its regenerating enzymes along with enhanced level of oxidative stress and damage to lipids and proteins. However, exogenous addition of ASC significantly reversed toxic effects of Cr(VI) in tomato roots. Furthermore, addition of lycorine (inhibitor of ASC biosynthesis) interestingly augmented Cr(VI) toxicity. However, exogenous addition of ASC reversed toxic effect of lycorine suggesting that endogenous ASC has role in alleviating Cr(VI) toxicity in tomato roots.
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3.
Chromium: Rise and Shine in Peritoneal Dialysis Patients?
Filler, G, McIntyre, C
Peritoneal dialysis international : journal of the International Society for Peritoneal Dialysis. 2019;(4):320-322
Abstract
Some trace elements are altered with chronic kidney disease. Selenium, zinc, and manganese tend to be wasted, and there is growing evidence that selenium deficiency is associated with mortality on dialysis. Other trace elements accumulate, such as chromium, cobalt, lead, molybdenum, and vanadium. The highest chromium levels are found in dialysis patients. The dialysis modality may further affect these levels, especially in hemodialysis patients, where even small contaminations in the dialysis feed water may lead to a concentration gradient that increases the concentration of certain trace elements. Chromium levels in peritoneal dialysis (PD) patients have been understudied. A single cross-sectional study found substantially higher chromium levels in PD patients. In that study, the chromium concentration in the spent dialysate decreased substantially, suggesting that PD fluid could be a source of chromium. Chromium-lactate complexes may have been formed, which are easily absorbed. In our center, we observed a decrease in chromium level when using physiological PD fluids. This review discusses the potential mechanisms and raises the question of whether this accumulation of chromium is unlikely to be associated with a beneficial outcome.
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4.
Exposure routes and health effects of heavy metals on children.
Al Osman, M, Yang, F, Massey, IY
Biometals : an international journal on the role of metal ions in biology, biochemistry, and medicine. 2019;(4):563-573
Abstract
Heavy metals are naturally existing elements that have relatively high atomic weight and a minimum density five times the density of water. Heavy metals have extensive applications in industries, homes, agriculture and medicine, leading to their wide distribution in the environment. Most heavy metals are reported to be highly toxic. They also have numerous exposure routes, including ingestion, inhalation, and dermal absorption, subsequently inducing some health effects resulting from human and heavy metals contact. The implications of heavy metals with regards to children's health have been noted to be more severe compared to adults. The element's harmful consequences on children health include mental retardation, neurocognitive disorders, behavioral disorders, respiratory problems, cancer and cardiovascular diseases. Much attention should be given to heavy metals because of their high toxicity potential, widespread use, and prevalence. This review therefore examines the exposure routes and health effects of mercury (Hg), lead (Pb), chromium (Cr), cadmium (Cd), and barium (Ba) on children. In addition, their toxic mechanisms are elucidated.
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5.
Chromium supplementation in women with polycystic ovary syndrome: Systematic review and meta-analysis.
Tang, XL, Sun, Z, Gong, L
The journal of obstetrics and gynaecology research. 2018;(1):134-143
Abstract
AIM: Increasing evidence has suggested that chromium supplementation may improve the clinical symptoms of polycystic ovary syndrome (PCOS), yet the results have been inconsistent. To derive a more precise estimation of the efficacy of chromium, a meta-analysis was performed. METHODS Studies published in PubMed, EMBASE and the Cochrane Library up to April 2017 were retrieved. Standardized mean differences (SMD) with 95%CI were calculated for net changes using random-effects or fixed-effects models. RESULTS A total of six randomized clinical trials (RCT) with 351 PCOS women were ultimately collected in this meta-analysis. All included RCT were of moderate-high quality. On pooled analysis, insulin resistance was significantly decreased (SMD, -0.84; 95%CI: -1.30 to -0.38; P = 0.0004), while the total testosterone (SMD, 0.36; 95%CI: 0.07-0.65; P = 0.02) and free testosterone (SMD, 0.80; 95%CI: 0.48-1.12; P < 0.00001) were markedly increased in chromium-treated PCOS patients compared with control groups. No significant difference was found in other indexes of insulin metabolism (body mass index, fasting insulin, fasting blood sugar and quantitative insulin sensitivity check index), hormone status (luteinizing hormone, follicle-stimulating hormone and prolactin) and lipid profiles (cholesterol and triglycerides) between the two groups. CONCLUSION Supplementation with chromium may not have significant benefits for women with PCOS. More RCT with low heterogeneity, however, are required to corroborate the present findings.
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6.
The Effects of Supplementation with Chromium on Insulin Resistance Indices in Women with Polycystic Ovarian Syndrome: A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Heshmati, J, Omani-Samani, R, Vesali, S, Maroufizadeh, S, Rezaeinejad, M, Razavi, M, Sepidarkish, M
Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme. 2018;(3):193-200
Abstract
Recently, the effects of nutritional supplementation on improvement or prevention of polycystic ovary syndrome (PCOS) have been considered. Several studies have been carried out on the effect of chromium supplementation in improving PCOS patients. This study aimed to summarize the available findings regarding the effect of chromium on improving the polycystic ovary syndrome. The review includes randomized controlled trials (RCTs) comparing chromium treatment with placebo or other treatments in women with PCOS. Women with PCOS diagnosed according to the ESHRE/ASRM or NIH criteria in reproductive age were eligible. Electronic searches using the MeSH terms were conducted in the following databases: Medline, Embase, Scopus, Web of Science, and The Cochrane Library. Effects were measured as weighted mean difference (WMD) and 95% confidence intervals (CI) for studies of PCOS and control subjects were calculated by using random-effects model. The initial search yielded potentially 100 relevant articles of randomized clinical trials on dietary chromium supplements: 16 from Pubmed, 36 from Embase, 29 from Scopus, and 19 from Web of Science. After studying these publications, 5 were potentially eligible and retrieved in full text. The five studies included in the meta-analysis reported data on 137 women with PCOS and 131 controls. A meta-analysis of 5 studies showed a non-significant difference in fasting insulin between chromium, and placebo or other treatment (mean difference (MD): -1.14; (95% CI: -4.11 to 1.83, p=0.45). We retrieved two randomized controlled trials, in which Quantitative Insulin Sensitivity Check Index (QUICKI) was compared between chromium, and placebo or other treatment in 156 women with PCOS. Meta-analysis of two RCTs showed no significant difference in QUICKI score between chromium and placebo (MD: 0.01; 95% CI: -0.01 to 0.04, p=0.34). Two randomized controlled trials compared Homeostatic Model Assessment-Insulin Resistance (HOMA-IR) between chromium, and placebo or other treatment in 81 women with PCOS. After combining the data, there was a significantly lower HOMA-IR in the chromium group (MD: -1.68; 95% CI: -2.42 to -0.94, p<0.001). One RCT reported a significant difference in Homeostatic Model Assessment-beta-cell function (HOMA-B) between chromium and placebo groups (-15.5±32.3 vs. +13.6±23.1, p<0.001). No significant effect of chromium on fasting insulin and QUICKI score was found in women with PCOS. Chromium supplementation significantly improved HOMA-IR and HOMA-B among patients with diabetes. The magnitude of the effect is small, and the clinical relevance is uncertain. Future trials in well characterized studies that address the limitations in the current evidence are needed before definitive claims can be made about the effect of chromium supplementation.
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7.
Chromium(VI) Toxicity in Legume Plants: Modulation Effects of Rhizobial Symbiosis.
Stambulska, UY, Bayliak, MM, Lushchak, VI
BioMed research international. 2018;:8031213
Abstract
Most legume species have the ability to establish a symbiotic relationship with soil nitrogen-fixing rhizobacteria that promote plant growth and productivity. There is an increasing evidence of reactive oxygen species (ROS) important role in formation of legume-rhizobium symbiosis and nodule functioning. Environmental pollutants such as chromium compounds can cause damage to rhizobia, legumes, and their symbiosis. In plants, toxic effects of chromium(VI) compounds are associated with the increased production of ROS and oxidative stress development as well as with inhibition of pigment synthesis and modification of virtually all cellular components. These metabolic changes result in inhibition of seed germination and seedling development as well as reduction of plant biomass and crop yield. However, if plants establish symbiosis with rhizobia, heavy metals are accumulated preferentially in nodules decreasing the toxicity of metals to the host plant. This review summarizes data on toxic effects of chromium on legume plants and legume-rhizobium symbiosis. In addition, we discussed the role of oxidative stress in both chromium toxicity and formation of rhizobial symbiosis and use of nodule bacteria for minimizing toxic effects of chromium on plants.
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8.
Biosorption and biotransformation of hexavalent chromium [Cr(VI)]: A comprehensive review.
Jobby, R, Jha, P, Yadav, AK, Desai, N
Chemosphere. 2018;:255-266
Abstract
Chromium (VI) is one of the most common environmental contaminant due to its tremendous industrial applications. It is non-biodegradable as it is a heavy metal, and hence, of major concern. Therefore, it is pertinent that the remediation method should be such that brings chromium within permissible limits before the effluent is discharged. Several different strategies are adopted by microorganisms for Cr (VI) removal mostly involving biosorption and biotransformation or both. These mechanisms are based on the surface nature of the biosorbent and the availability of reductants. This review article focuses on chromium pollution problem, its chemistry, sources, effects, remediation strategies by biological agents and detailed chromium detoxification mechanism in microbial cell. A summary of applied in situ and ex situ chromium bioremediation technologies is also listed. This can be helpful for developing technologies to be more efficient for Cr (VI) removal thereby bridging the gap between laboratory findings and industrial application for chromium remediation.
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9.
Chromium supplementation and polycystic ovary syndrome: A systematic review and meta-analysis.
Fazelian, S, Rouhani, MH, Bank, SS, Amani, R
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS). 2017;:92-96
Abstract
INTRODUCTION polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women. Some vitamins and mineral can play role in improvement of PCOS. Chromium (Cr) is an essential element in glucose and insulin homeostasis. However, findings are not consistent regarding PCOS improvement. Therefore, the purpose of this paper was to assess the effect of Cr supplementation in PCOS that have not yet fully been elucidated. METHODS We searched ISI Web of Science, MEDLINE (1966 to June 2016), Google Scholar databases and Proquest and identified eligible papers and extracted the following terms: total testosterone, DHEAS, insulin sensitivity, fasting glucose, fasting insulin, OGTT 1h glucose, OGTT 2h glucose (mg/dL), LH (mIU/mL), FSH, DHEAS, ferriman-Galwey score (FG score). We calculated overall effect size with random effects model, between-study heterogeneity with I square (I2) statistic. Publication bias was assessed using Begg's test regression. RESULT Totally, 7 RCTs were selected. Results indicated that Cr supplementation had a beneficial effect on BMI with effect size: -2.37 (kg/m2), 95% CI: -2.99, -1.76, p=0.001 and free testosterone concentration with effect size=-0.52 (pg/mL), 95% CI: -0.83, -0.23, p=0.001. Cr reduced fasting insulin in subgroup of studies with >10 participants with effect size: -0.86mIU/ml, 95% CI: -0.67, -0.17; p=0.001. Cr supplementation had no beneficial effects on reducing total testosterone, FG score, DHEA, FSH and LH. CONCLUSION This systematic review and meta-analysis shows that using Cr picolinate supplementation has beneficial effects on decreasing BMI, fasting insulin and free testosterone in PCOS patients.
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10.
Metallosis and cobalt - chrome intoxication after hip resurfacing arthroplasty.
Czekaj, J, Ehlinger, M, Rahme, M, Bonnomet, F
Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association. 2016;(3):389-94