The mutualistic symbiotic system formed by clumping arbuscular mycorrhizal fungi (AMF) and plants can remediate heavy metal-contaminated soils. However, the specific mechanisms underlying the interaction between AMF and inter-root microbial communities, particularly their impact on organic phosphorus (P) cycling, remain unclear. This study investigated the gene regulation processes involved in inter-root soil phosphorus cycling in wetland plants, specifically Iris tectorum, following inoculation with AMF under varying concentrations of chromium (Cr) stress. Through macro-genome sequencing, we analyzed the composition and structure of the inter-root soil microbial community associated with Iris tectorum under greenhouse pot conditions. The results demonstrated significant changes in the diversity and composition of the inter-root soil microbial community following AMF inoculation, with Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, and Bacteroidetes being the dominant taxa. Under Cr stress, species and gene co-occurrence network analysis revealed that AMF promoted the transformation process of organic phosphorus mineralization and facilitated inorganic phosphorus uptake. Additionally, network analysis of functional genes indicated strong aggregation of (pstS, pstA, pstC, TC.PIT, phoR, pp-gppA) genes, which collectively enhanced phosphorus uptake by plants. These findings shed light on the inter-root soil phosphorus cycling process during the co-remediation of Cr-contaminated soil by AMF-Iris tectorum symbiosis, providing valuable theoretical support for the application of AMF-wetland plant symbiosis systems to remediate heavy metal-contaminated soil.
- Klíčová slova
- Arbuscular mycorrhizal fungi, Cr, Iris tectorum, Metagenome, Phosphorus,
- MeSH
- chrom * metabolismus MeSH
- fosfor * metabolismus MeSH
- Iris (rostlina) metabolismus MeSH
- látky znečišťující půdu * metabolismus MeSH
- mykorhiza * fyziologie MeSH
- půdní mikrobiologie * MeSH
- rhizosféra * MeSH
- symbióza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom * MeSH
- fosfor * MeSH
- látky znečišťující půdu * MeSH
Fe-bearing clay minerals contain structural iron that can be redox-active and can participate in electron transfer reactions with aqueous species. Although these redox properties have been studied extensively in the past decade, questions remain about the respective roles of kinetic and thermodynamic constraints in establishing steady-state redox conditions. In this study, the reduction kinetics of aqueous Cr(VI) to Cr(III) by Fe(II) contained in the structure of reduced ferruginous clay samples (reference Nontronite NAu-1) was monitored with quick-XAS (X-ray absorption spectroscopy). These measurements revealed the occurrence of at least two reaction processes with contrasting fast and slow kinetic rates. According to mass and electron balance calculations, Fe(II) located at the edge of the clay mineral particles alone cannot account for the fast reactivity of the samples, pointing out the presence of electron transfer from the inner part of the clay mineral layer structure to the reactive sites. The Fe(II)/Fe(III) ratio in the clay structure quickly reached a steady state after each Cr(VI) addition to the solution. These steady-state conditions were consistent with either a complete depletion of the Cr(VI) reactant for the first spikes of Cr(VI) or a thermodynamic equilibrium between the redox couples, i.e., between structural Fe(III)/Fe(II) and aqueous Cr(VI)/Cr(III), after the pool of fast-reacting Fe(II) was depleted. These results highlight the need to consider kinetic and thermodynamic controls of clay structural iron redox reactivity to predict the fate of redox-sensitive contaminants in the environment.
- Klíčová slova
- Fe, chromium, clay minerals, kinetics, redox, thermodynamic equilibrium,
- MeSH
- chrom * chemie MeSH
- jíl MeSH
- kinetika MeSH
- oxidace-redukce MeSH
- rentgenová absorpční spektroskopie * metody MeSH
- silikáty hliníku * chemie MeSH
- termodynamika MeSH
- železo * chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom * MeSH
- jíl MeSH
- silikáty hliníku * MeSH
- železo * MeSH
The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0 mm to 13.0 ± 0.0 mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.
- Klíčová slova
- Bacillus spp, Antibiogram analysis, Heavy metals, Petroleum contaminated soil, Resistogram analysis, Ribotyping,
- MeSH
- antibakteriální látky * farmakologie MeSH
- Bacteria * účinky léků klasifikace izolace a purifikace genetika MeSH
- chrom metabolismus MeSH
- kadmium analýza MeSH
- látky znečišťující půdu * analýza MeSH
- mikrobiální testy citlivosti * MeSH
- olovo MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- ropa mikrobiologie analýza MeSH
- těžké kovy * farmakologie analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Pákistán MeSH
- Názvy látek
- antibakteriální látky * MeSH
- chrom MeSH
- kadmium MeSH
- látky znečišťující půdu * MeSH
- olovo MeSH
- půda MeSH
- ropa MeSH
- těžké kovy * MeSH
Stainless steel welders are exposed to heavy filler metals. We evaluated the concentration of these metals in whole blood and urine, and the relevant biochemical parameters in relation to the total chromosomal aberrations (CAs), chromatid-type (CTA-type, CTAs) and chromosome-type (CSA-type, CSAs), in 117 welders and control individuals. Statistically higher concentrations of the total Cr, Ni and Mn were observed in whole blood and urine of welders, and the concentrations were higher in welders who smoked. On the contrary, concentrations of urinary heavy metals Cr and Mn adjusted for creatinine were significantly higher in the control groups. A statistically higher frequency of total CAs was observed in the whole group of welders, and also in the non-smoking welders, as compared to controls. The frequency of total CAs significantly correlated with the concentration of Cr, Ni and Mn in whole blood (R=0.61, P˂0.0001, R=0.33, P˂0.0001 and R=0.66, P˂0.0001, respectively), with urinary concentrations of Ni and Mn (R=0.27, P=0.003 and R=0.28, P=0.003, respectively) and with urinary concentrations of Cr, Ni and Mn adjusted for creatinine (R=0.22, P=0.029, R=0.26, P=0.005 and R=0.20, P=0.030, respectively). Likewise, the frequency of CTA-types significantly correlated with the concentration of Cr and Mn in whole blood (R=0.31, P=0.0007 and R=0.34, P=0.0002). The frequency of CSA-types significantly correlated with concentrations of Cr, Ni and Mn in whole blood (R=0.43, P˂0.0001, R=0.38, P˂0.0001 and R=0.46, P˂0.0001, respectively). The statistically higher values of serum creatinine and total bilirubin were detected in all welders, as well as in smokers when compared to the corresponding controls. The exposure to heavy metals in welders increased the frequencies of CAs and altered the balance between urinary excretion of heavy metals and their possible accumulation.
- Klíčová slova
- Biochemical parameters, Chromosomal aberrations, Effects of smoking, Metal concentrations in urine and whole blood, Welders,
- MeSH
- chrom moč krev MeSH
- chromozomální aberace * chemicky indukované MeSH
- dospělí MeSH
- kouření škodlivé účinky moč krev MeSH
- kreatinin moč krev MeSH
- lidé středního věku MeSH
- lidé MeSH
- mangan moč krev MeSH
- nerezavějící ocel MeSH
- nikl moč krev MeSH
- pracovní expozice * škodlivé účinky analýza MeSH
- studie případů a kontrol MeSH
- svařování * MeSH
- těžké kovy * moč krev MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom MeSH
- kreatinin MeSH
- mangan MeSH
- nerezavějící ocel MeSH
- nikl MeSH
- těžké kovy * MeSH
Chromium (Cr) can interfere with plant gene expression, change the content of metabolites and affect plant growth. However, the molecular response mechanism of wetland plants at different time sequences under Cr stress has yet to be fully understood. In this study, Canna indica was exposed to 100 mg/kg Cr-contaminated soil for 0, 7, 14, and 21 days and analyzed using untargeted metabolomics (LC-MS) and transcriptomics. The results showed that Cr stress increased the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD), the contents of glutathione (GSH), malondialdehyde (MDA), and oxygen free radical (ROS), and inhibited the biosynthesis of photosynthetic pigments, thus leading to changes in plant growth and biomass. Metabonomics analysis showed that Cr stress mainly affected 12 metabolic pathways, involving 38 differentially expressed metabolites, including amino acids, phenylpropane, and flavonoids. By transcriptome analysis, a total of 16,247 differentially expressed genes (DEGs, 7710 up-regulated genes, and 8537 down-regulated genes) were identified, among which, at the early stage of stress (Cr contaminate seven days), C. indica responds to Cr toxicity mainly through galactose, starch and sucrose metabolism. With the extension of stress time, plant hormone signal transduction and MAPK signaling pathway in C. indica in the Cr14 (Cr contaminate 14 days) treatment group were significantly affected. Finally, in the late stage of stress (Cr21), C. indica co-defuses Cr toxicity by activating its Glutathione metabolism and Phenylpropanoid biosynthesis. In conclusion, this study revealed the molecular response mechanism of C. indica to Cr stress at different times through multi-omics methods.
- Klíčová slova
- Canna indica, Chromium, Metabolome, Physiology, Transcriptome,
- MeSH
- chrom metabolismus toxicita MeSH
- fyziologický stres * genetika MeSH
- látky znečišťující půdu toxicita metabolismus MeSH
- metabolom MeSH
- metabolomika * metody MeSH
- regulace genové exprese u rostlin * MeSH
- stanovení celkové genové exprese * MeSH
- transkriptom * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom MeSH
- látky znečišťující půdu MeSH
Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting bacteria enhance plant tolerance to abiotic stress and promote plant growth in contaminated soil. However, the interaction mechanism between rhizosphere microbial communities under chromium (Cr) stress remains unclear. This study conducted a greenhouse pot experiment and metagenomics analysis to reveal the comprehensive effects of the interaction between AMF (Rhizophagus intraradices) and nitrogen-N metabolizing plant growth promoters on the growth of Iris tectorum. The results showed that AMF significantly increased the biomass and nutrient levels of I. tectorum in contaminated soil and decreased the content of Cr in the soil. Metagenomics analysis revealed that the structure and composition of the rhizosphere microbial community involved in nitrogen metabolism changed significantly after inoculation with AMF under Cr stress. Functional genes related to soil nitrogen mineralization (gltB, gltD, gdhA, ureC, and glnA), nitrate reduction to ammonium (nirB, nrfA, and nasA), and soil nitrogen assimilation (NRT, nrtA, and nrtC) were up-regulated in the N-metabolizing microbial community. In contrast, the abundance of functional genes involved in denitrification (nirK and narI) was down-regulated. In addition, the inoculation of AMF regulates the synergies between the N-metabolic rhizosphere microbial communities and enhances the complexity and stability of the rhizosphere ecological network. This study provides a basis for improving plant tolerance to heavy metal stress by regulating the functional abundance of N-metabolizing plant growth-promoting bacteria through AMF inoculation. It helps to understand the potential mechanism of wetland plant remediation of Cr-contaminated soil.
- Klíčová slova
- Cr stress, Functional gene, Iris tectorum, Metagenome, Nitrogen metabolism, Rhizophagus intraradices,
- MeSH
- Bacteria MeSH
- chrom metabolismus MeSH
- dusík metabolismus MeSH
- houby MeSH
- Iris (rostlina) * genetika MeSH
- kořeny rostlin MeSH
- mykorhiza * metabolismus MeSH
- půda chemie MeSH
- rostliny MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom MeSH
- dusík MeSH
- půda MeSH
Chromium (Cr) stress significantly hinders crop production by disrupting nutrient uptake, impairing plant growth, and contaminating soil, posing a substantial threat to agricultural sustainability. The use of deashed biochar (DAB) and strigolactone can be an effective solution to mitigate this issue. Deashed biochar enhances crop production by improving soil structure, water retention, and nutrient availability while mitigating the bioavailability of toxic substances. Strigolactone boosts plant growth by stimulating root growth, branching, shoot formation, and overall plant physiology. Nevertheless, the scientific rationale behind their collective use as an amendment to counter Cr stress remains to be substantiated. Therefore, in this study, a blend of DAB and strigolactone was employed as additives in radish cultivation, both in the absence of Cr stress and under the influence of 200Cr stress. Four treatments, i.e., 0, 20µM Strigolactone, DAB, and 20µM Strigolactone + DAB, were applied in four replications following a completely randomized design. Results demonstrate that 20µM Strigolactone + DAB produced significant improvement in radish shoot length (27.29%), root length (45.60%), plant fresh weight (33.25%), and plant dry weight (78.91%), compared to the control under Cr stress. Significant enrichment in radish chlorophyll a (20.41%), chlorophyll b (58.53%), and total chlorophyll (31.54%) over the control under Cr stress, prove the efficacy of 20µM Strigolactone + DAB treatment. In conclusion, 20µM Strigolactone + DAB is the recommended amendment for mitigating Cr stress in radish. Farmers should consider using Strigolactone + DAB amendments to combat Cr stress and enhance radish growth, contributing to a more resilient agricultural ecosystem.
- Klíčová slova
- Antioxidant activity, Chlorophyll content, Chromium, Deashed biochar, Strigolactone,
- MeSH
- chlorofyl a MeSH
- chrom MeSH
- dřevěné a živočišné uhlí MeSH
- ekosystém MeSH
- heterocyklické sloučeniny tricyklické * MeSH
- laktony * MeSH
- látky znečišťující půdu * MeSH
- půda chemie MeSH
- Raphanus * MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- biochar MeSH Prohlížeč
- chlorofyl a MeSH
- chrom MeSH
- dřevěné a živočišné uhlí MeSH
- GR24 strigolactone MeSH Prohlížeč
- heterocyklické sloučeniny tricyklické * MeSH
- laktony * MeSH
- látky znečišťující půdu * MeSH
- půda MeSH
BACKGROUND: While much research has been done to identify individual workplace lung carcinogens, little is known about joint effects on risk when workers are exposed to multiple agents. OBJECTIVES: We investigated the pairwise joint effects of occupational exposures to asbestos, respirable crystalline silica, metals (i.e., nickel, chromium-VI), and polycyclic aromatic hydrocarbons (PAH) on lung cancer risk, overall and by major histologic subtype, while accounting for cigarette smoking. METHODS: In the international 14-center SYNERGY project, occupational exposures were assigned to 16,901 lung cancer cases and 20,965 control subjects using a quantitative job-exposure matrix (SYN-JEM). Odds ratios (ORs) and 95% confidence intervals (CIs) were computed for ever vs. never exposure using logistic regression models stratified by sex and adjusted for study center, age, and smoking habits. Joint effects among pairs of agents were assessed on multiplicative and additive scales, the latter by calculating the relative excess risk due to interaction (RERI). RESULTS: All pairwise joint effects of lung carcinogens in men were associated with an increased risk of lung cancer. However, asbestos/metals and metals/PAH resulted in less than additive effects; while the chromium-VI/silica pair showed marginally synergistic effect in relation to adenocarcinoma (RERI: 0.24; CI: 0.02, 0.46; p = 0.05). In women, several pairwise joint effects were observed for small cell lung cancer including exposure to PAH/silica (OR = 5.12; CI: 1.77, 8.48), and to asbestos/silica (OR = 4.32; CI: 1.35, 7.29), where exposure to PAH/silica resulted in a synergistic effect (RERI: 3.45; CI: 0.10, 6.8). DISCUSSION: Small or no deviation from additive or multiplicative effects was observed, but co-exposure to the selected lung carcinogens resulted generally in higher risk than exposure to individual agents, highlighting the importance to reduce and control exposure to carcinogens in workplaces and the general environment. https://doi.org/10.1289/EHP13380.
- MeSH
- azbest * toxicita MeSH
- chrom toxicita MeSH
- karcinogeny toxicita MeSH
- lidé MeSH
- nádory plic * chemicky indukované epidemiologie MeSH
- oxid křemičitý toxicita MeSH
- plíce MeSH
- polycyklické aromatické uhlovodíky * toxicita MeSH
- pracovní expozice * MeSH
- studie případů a kontrol MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- azbest * MeSH
- chrom MeSH
- chromium hexavalent ion MeSH Prohlížeč
- karcinogeny MeSH
- oxid křemičitý MeSH
- polycyklické aromatické uhlovodíky * MeSH
The toxicity of hexavalent chromium (Cr(VI)) present in the environment has exceeded the current limits or standards and thus may lead to biotic and abiotic catastrophes. Accordingly, several treatments, including chemical, biological, and physical approaches, are being used to reduce Cr(VI) waste in the surrounding environment. This study compares the Cr(VI) treatment approaches from several areas of science and their competence in Cr(VI) removal. As an effective combination of physical and chemical approaches, the coagulation-flocculation technique removes more than 98% of Cr(VI) in less than 30 min. Most membrane filtering approaches can remove up to 90% of Cr(VI). Biological approaches that involve the use of plants, fungi, and bacteria also successfully eliminate Cr(VI) but are difficult to scale up. Each of these approaches has its benefits and drawbacks, and their applicability is determined by the research aims. These approaches are also sustainable and environmentally benign, thus limiting their effects on the ecosystem.
- Klíčová slova
- Cr(VI) removal, Cr(VI) treatment, Environment, Heavy metal, Hexavalent chromium, Water pollution,
- MeSH
- chemické látky znečišťující vodu * MeSH
- chrom toxicita MeSH
- ekosystém MeSH
- voda * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- chemické látky znečišťující vodu * MeSH
- chrom MeSH
- chromium hexavalent ion MeSH Prohlížeč
- voda * MeSH
Chromium (Cr) can disrupt a plant's normal physiological and metabolic functions and severely impact the microenvironment. However, limited studies have investigated the impact of arbuscular mycorrhizal fungi (AMF) inoculation on the rhizosphere microorganisms of Iris tectorum under Cr stress, and the mechanisms of how rhizosphere microorganisms interact with hosts and contaminants. In this study, we investigated the effects of AMF inoculation on the growth, absorption of nutrients and heavy metals, and functional genes of the rhizosphere microbial community of I. tectorum under Cr stress in a greenhouse pot experiment. The results showed that AMF significantly increased the biomass and nutrient levels of I. tectorum, while decreasing the content of Cr in soil. Furthermore, metagenome analysis demonstrated significant changes in the structure and composition of the rhizosphere microbial community after AMF formed a mycorrhizal symbiosis system with the I. tectorum. Specifically, the abundance of functional genes related to nutrient cycling (N, P) and heavy metal resistance (chrA and arsB), as well as the abundance of heavy metal transporter family (P-atPase, MIT, CDF, and ABC) in the rhizosphere microbial community were up-regulated and their expression. Additionally, the synergies between rhizosphere microbial communities were regulated, and the complexity and stability of the rhizosphere microbial ecological network were enhanced. This study provides evidence that AMF can regulate rhizosphere microbial communities to improve plant growth and heavy metal stress tolerance, and helps us to understand the potential mechanism of wetland plant remediation of Cr-contaminated soil under AMF symbiosis.
- Klíčová slova
- AMF, Cr stress, Functional gene, Iris tectorum, Metagenome, Rhizosphere microbial community,
- MeSH
- chrom analýza MeSH
- exprese genu MeSH
- houby MeSH
- Iris (rostlina) * MeSH
- kořeny rostlin mikrobiologie MeSH
- metagenomika MeSH
- mikrobiota * MeSH
- mykorhiza * fyziologie MeSH
- půda chemie MeSH
- půdní mikrobiologie MeSH
- rhizosféra MeSH
- těžké kovy * analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chrom MeSH
- půda MeSH
- těžké kovy * MeSH
