scholarly journals Analysis of co-regulated abundance of genes associated with arsenic and phosphate metabolism in Andean Microbial Ecosystems

2019 ◽  
Author(s):  
L.A. Saona ◽  
S. Valenzuela-Diaz ◽  
D. Kurth ◽  
M. Contreras ◽  
C. Meneses ◽  
...  
Keyword(s):  
High Temperature ◽  
Physicochemical Parameters ◽  
Microbial Mats ◽  
Biological Function ◽  
Arsenic Concentration ◽  
Phosphate Metabolism ◽  
Arsenic Metabolism ◽  
Hypersaline Lakes ◽  
Microbial Ecosystems ◽  
High Arsenic

AbstractPhosphate and arsenate are very similar compounds, and there is great interest in studying their relationship and their interaction with biological systems. Despite having no apparent biological function, specific genes regulate arsenic interaction with cells and can be located in regions of the genome called arsenic islands, where phosphate metabolism genes are also present. Although they are neighboring genes, the nature of their relationship and how they have been selected is still unknown.In this work, we analyzed the metagenomes of the four microbial ecosystems inhabiting hypersaline lakes of the Argentine Puna and the Atacama salt flat in Chile and have evaluated the presence and abundance of both arsenic and phosphate metabolism genes. The samples analyzed included microbialites, biofilms and microbial mats; all of them established under high arsenic concentrations, high UV radiation and high temperature fluctuation, among others.The results show great differences in the dispersion and abundance of genes related to both phosphate and arsenic metabolism in the analyzed samples. The main difference is given in the Diamante Lake, located in the crater of the Galan volcano characterized by being one of the lakes with the highest arsenic concentration (2.34 mM). Correlating genes abundance with the physicochemical parameters of the lakes studied, our results suggest that arsenic and phosphate metabolism are intricately co-regulated in environmental conditions.

Study of dislocation loops in Arsenic-Rich as-grown GaAs

1987 ◽  
Vol 45 ◽  
pp. 350-351
Author(s):  
Byung-Teak Lee
Keyword(s):  
Point Defects ◽  
Electronic Devices ◽  
Arsenic Concentration ◽  
Stoichiometric Compound ◽  
Dislocation Loops ◽  
Gaas Crystal ◽  
Ion Milling ◽  
Transmission Electron ◽  
Arsenic Source ◽  
High Arsenic

Grown-in dislocations in GaAs have been a major obstacle in utilizing this material for the potential electronic devices. Although it has been proposed in many reports that supersaturation of point defects can generate dislocation loops in growing crystals and can be a main formation mechanism of grown-in dislocations, there are very few reports on either the observation or the structural analysis of the stoichiometry-generated loops. In this work, dislocation loops in an arsenic-rich GaAs crystal have been studied by transmission electron microscopy.The single crystal with high arsenic concentration was grown using the Horizontal Bridgman method. The arsenic source temperature during the crystal growth was about 630°C whereas 617±1°C is normally believed to be optimum one to grow a stoichiometric compound. Samples with various orientations were prepared either by chemical thinning or ion milling and examined in both a JEOL JEM 200CX and a Siemens Elmiskop 102.

scholarly journals Synonymous single nucleotide polymorphism in arsenic (+3) methyltransferase of the Western mosquitofish (Gambusia affinis) and its gene expression among field populations

Ecotoxicology ◽  
2021 ◽  
Author(s):  
Daesik Park ◽  
Catherine R. Propper ◽  
Guangning Wang ◽  
Matthew C. Salanga
Keyword(s):  
Gene Expression ◽  
Sequence Variation ◽  
Allelic Variation ◽  
Arsenic Concentration ◽  
Gambusia Affinis ◽  
Contamination Level ◽  
Water Medium ◽  
Single Nucleotide ◽  
Wide Range ◽  
High Arsenic

AbstractNaturally occurring arsenic is toxic at extremely low concentrations, yet some species persist even in high arsenic environments. We wanted to test if these species show evidence of evolution associated with arsenic exposure. To do this, we compared allelic variation across 872 coding nucleotides of arsenic (+3) methyltransferase (as3mt) and whole fish as3mt gene expression from three field populations of Gambusia affinis, from water sources containing low (1.9 ppb), medium-low (3.3 ppb), and high (15.7 ppb) levels of arsenic. The high arsenic site exceeds the US EPA’s Maximum Contamination Level for drinking water. Medium-low and high populations exhibited homozygosity, and no sequence variation across all animals sampled. Eleven of 24 fish examined (45.8%) in the low arsenic population harbored synonymous single nucleotide polymorphisms (SNPs) in exons 4 and/or 10. SNP presence in the low arsenic population was not associated with differences in as3mt transcript levels compared to fish from the medium-low site, where SNPs were noted; however, as3mt expression in fish from the high arsenic concentration site was significantly lower than the other two sites. Low sequence variation in fish populations from sites with medium-low and high arsenic concentrations suggests greater selective pressure on this allele, while higher variation in the low population suggests a relaxed selection. Our results suggest gene regulation associated with arsenic detoxification may play a more crucial role in influencing responses to arsenic than polymorphic gene sequence. Understanding microevolutionary processes to various contaminants require the evaluation of multiple populations across a wide range of pollution exposures.

scholarly journals Urinary arsenic concentration in a high arsenic area of south west England.

1997 ◽  
Vol 54 (11) ◽  
pp. 840-840 ◽  
Author(s):  
P Kavanagh ◽  
M E Farago ◽  
I Thornton ◽  
P Elliott ◽  
W Goessler ◽  
...  
Keyword(s):  
Arsenic Concentration ◽  
Urinary Arsenic ◽  
South West ◽  
South West England ◽  
High Arsenic

scholarly journals Groundwater Arsenic Distribution in India by Machine Learning Geospatial Modeling

2020 ◽  
Vol 17 (19) ◽  
pp. 7119 ◽  
Author(s):  
Joel Podgorski ◽  
Ruohan Wu ◽  
Biswajit Chakravorty ◽  
David A. Polya
Keyword(s):  
Drinking Water ◽  
Urban Areas ◽  
Arsenic Concentration ◽  
Environmental Parameters ◽  
Predictor Variables ◽  
High Exposure ◽  
Rural And Urban Areas ◽  
Rural And Urban ◽  
Environmental Public Health Tracking ◽  
High Arsenic

Groundwater is a critical resource in India for the supply of drinking water and for irrigation. Its usage is limited not only by its quantity but also by its quality. Among the most important contaminants of groundwater in India is arsenic, which naturally accumulates in some aquifers. In this study we create a random forest model with over 145,000 arsenic concentration measurements and over two dozen predictor variables of surface environmental parameters to produce hazard and exposure maps of the areas and populations potentially exposed to high arsenic concentrations (>10 µg/L) in groundwater. Statistical relationships found between the predictor variables and arsenic measurements are broadly consistent with major geochemical processes known to mobilize arsenic in aquifers. In addition to known high arsenic areas, such as along the Ganges and Brahmaputra rivers, we have identified several other areas around the country that have hitherto not been identified as potential arsenic hotspots. Based on recent reported rates of household groundwater use for rural and urban areas, we estimate that between about 18–30 million people in India are currently at risk of high exposure to arsenic through their drinking water supply. The hazard models here can be used to inform prioritization of groundwater quality testing and environmental public health tracking programs.

Understanding the thermal decomposition of gold concentrates with high arsenic concentration

2018 ◽  
pp. 44-48
Author(s):  
P. A. Gulyashinov ◽  
◽  
P. L. Paleev ◽  
A. K. Subanakov ◽  
A. N. Gulyashinov ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Arsenic Concentration ◽  
High Arsenic

Release Behaviors of Arsenic in Fine Particles Generated from a Typical High-Arsenic Coal at a High Temperature

2016 ◽  
Vol 30 (8) ◽  
pp. 6201-6209 ◽  
Author(s):  
Chong Tian ◽  
Rajender Gupta ◽  
Yongchun Zhao ◽  
Junying Zhang
Keyword(s):  
High Temperature ◽  
Fine Particles ◽  
High Arsenic

scholarly journals The Behavior of Arsenic during the Thermal and Chemical Decomposition of the Ammonium–Arsenic Jarosite

2016 ◽  
Author(s):  
Mizraim Flores ◽  
Francisco Patiño ◽  
Elia G. Palacios ◽  
Iván Reyes ◽  
Martín Reyes ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Alkaline Medium ◽  
High Temperatures ◽  
Solid Phase ◽  
Arsenic Concentration ◽  
Incongruent Dissolution ◽  
Chemical Decomposition ◽  
Wide Range ◽  
Ammonium Jarosite ◽  
High Arsenic

Arsenic, an element of environmental impact, can be incorporated into jarosite–type compounds and remain stabilised within the structure under a wide range of environmental conditions. In this study, a sample of ammonium–arsenic jarosite was synthesised by precipitation in sulphate medium at controlled pH of 1.2–1.8. The behaviour of arsenic during the thermal and chemical decomposition of jarosite was analysed; the degradation in alkaline medium of jarosite was also studied. According to the results, the synthesised jarosite is composed of joined rhombohedral crystals, forming tightly spherical shaped particles, 37–54 μm size. The ammonium jarosite produced possessed a high arsenic concentration; its calculated stoichiometry being (NH4)Fe2.45[(SO4)1.80(AsO4)0.20][(OH)4.15(H20)1.85]. It was found that arsenic is stabilised in the jarosite structure; upon heating, it remains in residual solids above 700°C, whilst in alkaline medium an incongruent dissolution takes place, with the arsenic retained in the solid phase along with iron. These solids, when exposed to high temperatures (1200°C), transform into a type of iron oxide known as hematite, so with arsenic it is retained an iron compound forming a stable compound which withstands high temperatures.

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