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Arsenic (As), a heavy metalloid, occupies the topmost position in the list of the top ten hazardous chemicals published by the World Health Organization. The contamination of arsenic in groundwater predominantly utilized for irrigation and drinking is responsible for serious public health issues across the globe. The two most common arsenic species...
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... respectively. Organic As species which are commonly available in the environment are monomethylarsenate [(MMAs(V)], dimethylarsenate [DMAs(V)], trimethylarsine oxide [TMAs(V)O], monomethylarsenite [MMAs(III)], dimethylarsenite [DMAs(III)], arsenosugars, arsenosugar phospholipids, and arsenobetaine ( Ali et al. 2020;Flora 2015;Zhu et al. 2014) (Fig. 1). Organic phenylarsenical compounds, namely, roxarsone (4-hydroxy-3-nitrophenylarsonic acid), p-arsanilic acid (4-aminophenylarsonic acid), and nitarsone (4-nitrophenylarsonic acid) have extensively been utilized in significant quantities in livestock farming for growth promotion, disease control, and meat pigmentation. However, ...
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Purpose of Review
This review summarizes inorganic arsenic (iAs) metabolism and toxicity in mice and the gut microbiome and how iAs and the gut microbiome interact to induce diseases.
Recent Findings
Recently, a variety of studies have started to reveal the interactions between iAs and the gut microbiome. Evidence shows that gut bacteria can influ...
Citations
... The respiratory reduction of As(V) to As(III) is carried out by the arsenate reduction system (arr), composed of the arrA genes. As(V) reduction is catalyzed by the enzyme arsenate reductase (Arr) under anoxic conditions and is a periplasmic dimethylsulfoxide (DMSO) reductase that is composed of two heterologous subunits, one large (ArrA) of 87 kDa and one small (ArrB) of 29 kDa (Yan et al. 2019;Zhai et al. 2020;Singh et al. 2021 (Kumari and Jagadevan 2016). Arsenate reducing microorganisms (ARMs) reduce As(V) to As(III) as a final electron acceptor to survive the high arsenic concentrations in the various environments in which they thrive. ...
Bioremediation is an ingenious and promising method pertinent for recuperating and removing toxic metals in polluted water and lands. Arsenic (As) contamination is a crucial matter worldwide as its supersaturation is gradually intensifying in our environment because of natural and anthropogenic exertion. Microorganisms have a pivotal role in the bioremediation of various arsenic species. Microorganisms can presumably decrease arsenic by employing genetic engineering. By introducing innovative catabolic pathways with the help of different computational tools or by engineering the prevailing metabolic pathways, the limitations likely to crop up in bioremediation can be suppressed. This review accentuates the significance of microbes for the bioremediation of arsenic, and along with that, it scrutinizes the disadvantages and incapability of native and engineered microbes for bioremediation. In addition, arsenic bioremediation employing genetically modified bacteria is more ecologically friendly. It has fewer health hazards than physiochemical-based methods such as coagulation or filtration sedimentation, electrodialysis or osmosis, chemical precipitations, and adsorptions.
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Biogeochemical reduction and mobilization of sediment-bound arsenic (As) is the major concern for widespread groundwater As contamination in the middle Gangetic plains. The present work examines a microcosm based bio-stimulation study and substrate amendments over 45 days to analyze the bacterial community structure and distribution to indicate the possible in-situ bioremediation strategy in the area. Initially, Bacterial phyla Proteobacteria was predominantly present in all the samples, followed by Actinobacteria, Bacteroidetes, and Firmicutes whereas Cyanobacteria was noted as the minor group. In genus level, Delftia, Acinetobacter, Lysobacter, Bacillus, and Pseudomonas were the major groups of bacteria in the As-rich aquifer system, while Planctomycetes dominated the bio-stimulated samples, followed by a minute portion of Proteobacteria. Alpha diversity and Chaol curve further determined the species richness in the samples with an As tolerant capacity of 152.28 ppb. The presence of γ-Proteobacteria as the dominating member in high As-content water indicated their predominant role in As mobilization, whereas, dominance of α-Proteobacterial members in low As-content water indicated their involvement in As detoxification. The complete change in microbial community structure within the bio-stimulated conditions indicated the extensive role of arsenite-oxidizing microbial communities within different levels of As-contaminated areas in Bihar that will enlighten the significant role of these communities in As-biogeochemical cycle.
Supplementary information:
The online version contains supplementary material available at 10.1007/s13205-023-03612-0.
Arsenic (As) is one of the most toxic metalloids present in soil and water resources. The presence of microorganisms in soil and aqueous media have a significant impact on the toxicity of arsenic because the microorganisms interact with it in different ways such as sorption, reduction, oxidation and methylation etc. This chapter covers the microbial processes which have the impact on the fate as well as mobility of As in the environment with a special focus on the role of bacteria in defining the fates of As. The dominant bacterial As biotransformations which define its mobility and toxic impacts in the environment include the arsenite [As(III)] oxidation, arsenate [As(V)] oxidation, methylation, demethylation and volatilization. However, the different biotransformations of As by bacterial are affected by the changes in pH, redox potential, nutrient availabilities and presence of different interacting substances such organic matter etc.
Cadmium (Cd) pollution in agricultural soils has become a great concern for global food security and the environment. Cd is a nonessential heavy metal and a group-I carcinogen. Excessive uses of phosphate fertilizers, dispersal of municipal waste, sewage sludge disposal and atmospheric deposition have polluted agricultural soils with cadmium. Accumulation of Cd in crops may cause severe damages to plant growth and agricultural productivity. Human beings get exposed to cadmium toxicity through the food chain. In recent times, plant growth-promoting rhizobacteria (PGPR)-mediated Cd detoxification in plants emerged as an excellent alternative to physicochemical approaches as it is economical and environmentally sustainable. Generally, PGPR enhances plant growth by nitrogen fixation, producing phytohormones, ACC deaminase (ACCD), siderophores, and solubilizing inorganic or organic phosphates. PGPR enhance Cd bioremediation through different mechanisms, such as biosorption, complexation, chelation, sequestration and biotransformation. The application of Cd resistant PGPR to alleviate Cd stress in plants has an exciting prospect, and early findings look promising for boosting food security, especially in contaminated soil, for the increasing global population.KeywordsACC deaminaseBioremediationCadmiumDetoxificationImmobilizationPlant growth promoting rhizobacteria (PGPR)Siderophore
