The degradation of arsenoribosides from Ecklonia radiata tissues decomposed in natural and microbially manipulated microcosms

2014 ◽  
Vol 11 (3) ◽  
pp. 289 ◽  
Author(s):  
Elliott G. Duncan ◽  
William A. Maher ◽  
Simon D. Foster ◽  
Frank Krikowa ◽  
Katarina M. Mikac

Environmental context Arsenoribosides are the major arsenic species in marine macro-algae, yet inorganic arsenic is the major arsenic species found in seawater. We investigated the degradation of arsenoribosides associated with Ecklonia radiata by the use of microcosms containing both natural and autoclaved seawater and sand. The decomposition and persistence of arsenic species was linked to the use of autoclaved seawater and sand, which suggests that arsenoriboside degradation is governed by the microbial composition of microenvironments within marine systems. Abstract We investigated the influence of microbial communities on the degradation of arsenoribosides from E. radiata tissues decomposing in sand and seawater-based microcosms. During the first 30 days, arsenic was released from decomposing E. radiata tissues into seawater and sand porewaters in all microcosms. In microcosms containing autoclaved seawater and autoclaved sand, arsenic was shown to persist in soluble forms at concentrations (9–18µg per microcosm) far higher than those present initially (~3µg per microcosm). Arsenoribosides were lost from decomposing E. radiata tissues in all microcosms with previously established arsenoriboside degradation products, such as thio-arsenic species, dimethylarsinoylethanol (DMAE), dimethylarsenate (DMA) and arsenate (AsV) observed in all microcosms. DMAE and DMA persisted in the seawater and sand porewaters of microcosms containing autoclaved seawater and autoclaved sand. This suggests that the degradation step from arsenoribosides → DMAE occurs on algal surfaces, whereas the step from DMAE → AsV occurs predominantly in the water-column or sand–sediments. This study also demonstrates that disruptions to microbial connectivity (defined as the ability of microbes to recolonise vacant habitats) result in alterations to arsenic cycling. Thus, the re-cycling of arsenoribosides released from marine macro-algae is driven by microbial complexity plus microbial connectivity rather than species diversity as such, as previously assumed.

2012 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
A. Price ◽  
W. Maher ◽  
J. Kirby ◽  
F. Krikowa ◽  
E. Duncan ◽  
...  

Environmental contextAlthough arsenic occurs at high concentrations in many marine systems, the influencing factors are poorly understood. The arsenic content of sediments, detritus, suspended particles and organisms have been investigated from different trophic levels in an open seagrass ecosystem. Total arsenic concentrations and arsenic species were organism-specific and determined by a variety of factors including exposure, diet and the organism physiology. AbstractThe distribution and speciation of arsenic within an open marine seagrass ecosystem in Lake Macquarie, NSW, Australia is described. Twenty-six estuarine species were collected from five trophic groups (autotrophs, suspension-feeders, herbivores, detritivores and omnivores, and carnivores). Sediment, detritus, epibiota and micro-invertebrates were also collected and were classified as arsenic source samples. There were no significant differences in arsenic concentrations between trophic groups and between pelagic and benthic feeders. Benthic-dwelling species generally contained higher arsenic concentrations than pelagic-dwelling species. Sediments, seagrass blades and detritus contained mostly inorganic arsenic (50–90 %) and arsenoribosides (10–26 %), with some methylarsonate (9.4–14.6 %) and dimethyarsinate (7.9–9.7 %) in seagrass blades and detritus. Macroalgae contained mostly arsenoribosides (40–100 %). Epibiota and other animals contained predominately arsenobetaine (63–100 %) and varying amounts of dimethyarsinate (0–26 %), monomethyarsonate (0–14.6 %), inorganic arsenic (0–2 %), trimethylarsenic oxide (0–6.6 %), arsenocholine (0–12 %) and tetramethylarsonium ion (0–4.5 %). It was concluded that arsenic concentrations and species within the organisms of the Lake Macquarie ecosystem are species-specific and determined by a variety of factors including exposure, diet and the physiology of the organisms.


2011 ◽  
Vol 8 (1) ◽  
pp. 44 ◽  
Author(s):  
Jana Navratilova ◽  
Georg Raber ◽  
Steven J. Fisher ◽  
Kevin A. Francesconi

Environmental context Despite high levels of complex organoarsenic compounds in marine organisms, arsenic in seawater is present almost entirely as inorganic species. We examine the arsenic products from a marine alga allowed to decompose under simulated natural coastal conditions, and demonstrate a multi-step conversion of organic arsenicals to inorganic arsenic. The results support the hypothesis that the arsenic marine cycle begins and ends with inorganic arsenic. Abstract Time series laboratory experiments were performed to follow the degradation of arsenic compounds naturally present in marine algae. Samples of the brown alga Ecklonia radiata, which contains three major arsenosugars, were packed into 12 tubes open to air at one end only, and allowed to naturally decompose under moist conditions. During the subsequent 25 days, single tubes were removed at intervals of 1–4 days; their contents were cut into four sections (from open to closed end) and analysed for arsenic species by HPLC/ICPMS following an aqueous methanol extraction. In the sections without direct contact with air, the original arsenosugars were degraded primarily to arsenate via two major intermediates, dimethylarsinoylethanol (DMAE) and dimethylarsinate (DMA). The section with direct contact with air degraded more slowly and significant amounts of arsenosugars remained after 25 days. We also report preliminary data suggesting that the amount of non-extractable or recalcitrant arsenic (i.e. insoluble after sequential extractions with water/methanol, acetone, and hexane) increased with time. Furthermore, we show that treatment of the pellet with 0.1-M trifluoroacetic acid at 95°C solubilises a significant amount of this recalcitrant arsenic, and that the arsenic is present mainly as a cationic species of currently unknown structure.


2015 ◽  
Vol 12 (2) ◽  
pp. 149 ◽  
Author(s):  
Elliott G. Duncan ◽  
William A. Maher ◽  
Simon D. Foster

Environmental context In marine environments, inorganic arsenic present in seawater is transformed to organoarsenic species, mainly arsenoribosides in algae and arsenobetaine in animals. These transformations decrease the toxicity of arsenic, yet the fate of arsenoribosides and arsenobetaine when marine organisms decompose is unknown. We review the current literature on the degradation of these organoarsenic species in marine systems detailing the drivers behind their degradation, and also discuss the environmental relevance of laboratory-based experiments. Abstract Despite arsenoribosides and arsenobetaine (AB) being the major arsenic species in marine macro-algae and animals they have never been detected in seawater. In all studies reviewed arsenoribosides from marine macro-algae were degraded to thio-arsenoribosides, dimethylarsinoylethanol (DMAE), dimethylarsenate (DMA), methylarsenate (MA) with arsenate (AsV) the final product of degradation. The use of different macro-algae species and different experimental microcosms did not influence the arsenoriboside degradation pathway. The use of different experimental approaches, however, did influence the rate and extent at which arsenoriboside degradation occurred. This was almost certainly a function of the complexity of the microbial community within the microcosm, with greater complexity resulting in rapid and more complete arsenoriboside degradation. AB from decomposing animal tissues is degraded to trimethylarsine oxide (TMAO) or dimethylarsenoacetate (DMAA), DMA and finally AsV. The degradation of AB unlike arsenoribosides occurs via a dual pathway with environmental or microbial community variability influencing the pathway taken. The environmental validity of different experimental approaches used to examine the fate of organoarsenic species was also reviewed. It was evident that although liquid culture incubation studies are cheap and reproducible they lack the ability to culture representative microbial communities. Microcosm studies that include sand and sediment are more environmentally representative as they are a better simulation of marine ecosystems and are also likely to facilitate complex microbial communities. An added benefit of microcosm studies is that they are able to be run in parallel with field-based research to provide a holistic assessment of the degradation of organoarsenic species in marine environments.


2014 ◽  
Vol 79 (7) ◽  
pp. 815-828 ◽  
Author(s):  
Nikola Ilic ◽  
Slavica Lazarevic ◽  
Vladana Rajakovic-Ognjanovic ◽  
Ljubinka Rajakovic ◽  
Djordje Janackovic ◽  
...  

The sorption of inorganic arsenic species, As(III) and As(V), from water by sepiolite modified with hydrated iron(III) oxide was investigated at 25 ?C through batch studies. The influence of the initial pH value, the initial As concentrations, the contact time and types of water on the sorption capacity was investigated. Two types of water were used, deionized and groundwater. The maximal sorption capacity for As(III) from deionized water was observed at initial and final pH value 7.0, while the bonding of As(V) was observed to be almost pH independent for pH value in the range from 2.0 to 7.0, and the significant decrease in the sorption capacity was observed at pH values above 7.0. The sorption capacity at initial pH 7.0 was about 10 mg g?1 for As(III) and 4.2 mg g?1 for As(V) in deionized water. The capacity in groundwater was decreased by 40 % for As(III) and by 20 % for As(V). The Langmuir model and pseudo-second order kinetic model revealed good agreement with the experimental results. The results show that Fe(III)-modified sepiolite exhibits significant affinity for arsenic removal and it has a potential for the application in water purification processes.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ingrid E. Meyer-Cifuentes ◽  
Johannes Werner ◽  
Nico Jehmlich ◽  
Sabine E. Will ◽  
Meina Neumann-Schaal ◽  
...  

AbstractThe degradation of synthetic polymers by marine microorganisms is not as well understood as the degradation of plastics in soil and compost. Here, we use metagenomics, metatranscriptomics and metaproteomics to study the biodegradation of an aromatic-aliphatic copolyester blend by a marine microbial enrichment culture. The culture can use the plastic film as the sole carbon source, reaching maximum conversion to CO2 and biomass in around 15 days. The consortium degrades the polymer synergistically, with different degradation steps being performed by different community members. We identify six putative PETase-like enzymes and four putative MHETase-like enzymes, with the potential to degrade aliphatic-aromatic polymers and their degradation products, respectively. Our results show that, although there are multiple genes and organisms with the potential to perform each degradation step, only a few are active during biodegradation.


Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3093
Author(s):  
Hyojin Kim ◽  
Yangwon Jeon ◽  
Woonwoo Lee ◽  
Geupil Jang ◽  
Youngdae Yoon

It has recently been discovered that organic and inorganic arsenics could be detrimental to human health. Although organic arsenic is less toxic than inorganic arsenic, it could form inorganic arsenic through chemical and biological processes in environmental systems. In this regard, the availability of tools for detecting organic arsenic species would be beneficial. Because As-sensing biosensors employing arsenic responsive genetic systems are regulated by ArsR which detects arsenics, the target selectivity of biosensors could be obtained by modulating the selectivity of ArsR. In this study, we demonstrated a shift in the specificity of E. coli cell-based biosensors from the detection of inorganic arsenic to that of organic arsenic, specifically phenylarsine oxide (PAO), through the genetic engineering of ArsR. By modulating the number and location of cysteines forming coordinate covalent bonds with arsenic species, an E. coli cell-based biosensor that was specific to PAO was obtained. Despite its restriction to PAO at the moment, it offers invaluable evidence of the potential to generate new biosensors for sensing organic arsenic species through the genetic engineering of ArsR.


2020 ◽  
Vol 12 (3) ◽  
pp. 837
Author(s):  
Katarzyna Nocoń ◽  
Wioletta Rogula-Kozłowska ◽  
Grzegorz Majewski ◽  
Patrycja Rogula-Kopiec

This paper presents results of the research on soluble inorganic As(III) and As(V) bound to submicron atmospheric particles (PM1) in two Polish urban background sites (Zabrze and Warsaw). The purpose of the research was to give some insight on the susceptibility to leaching of PM1-bound arsenic species from easily water-soluble compounds, i.e., considered potentially bioavailable based on its daily and seasonal changes. Quantitative analysis for 120 PM1 samples (collected from 24 June 2014 to 8 March 2015) was performed by using a high-performance liquid chromatography in combination with inductively coupled plasma mass spectrometry. The mean seasonal concentrations of dominant soluble As specie—As(V)—ranged from 0.27 ng/m3 in the summer season in Warsaw to 2.41 ng/m3 in the winter season in Zabrze. Its mean mass shares in total As were 44% in Warsaw and 75% in Zabrze in the winter and 18% and 48%, respectively, in the summer. Obtained results indicated fossil fuel combustion as the main source of PM1-bound As(V) and road traffic emission as its minor sources. In opposite to As(V), soluble As(III) was not clearly seasonally variable. In both seasons, its mean concentrations were higher in Zabrze than in Warsaw. As(III) concentrations were not preferentially shaped by an exact emission from road traffic in both cities.


2009 ◽  
Vol 71-73 ◽  
pp. 121-124 ◽  
Author(s):  
Lukasz Drewniak ◽  
Renata Matlakowska ◽  
Aleksandra Sklodowska

The aim of this review report was to summarize knowledge about arsenic-metabolizing bacteria isolated from Zloty Stok (SW Poland) gold mine and determine their potential role in mobilization of arsenic. Three physiologically different groups of arsenic metabolizing microorganisms (arsenite oxidizers, dissmiliatory arsenate reducers and arsenic resistant microbes) were isolated from the deepest section of Gertruda Adit in Zloty Stok (SW Poland) gold mine. Twenty two strains were isolated from the rock biofilms and seven from arsenic-rich bottom sediments. Analysis of the 16S rRNA gene sequence of isolated bacteria revealed them to be members of the genera: Aeromonas, Arthrobacter, Bacillus, Brevundimonas, Chryseobacterium, Desemzia, Microbacterium, Micrococcus, Paracoccus, Pseudomonas, Rhodococcus, Serratia, Shewanella, Sinorhizobium, Sphingomonas, Stenotrophomonas and Streptomyces. All of the isolated bacteria were resistant to both inorganic arsenic species: arsenate [As(V)] and arsenite [As(III)]. One of the bottom sediments isolates (Sinorhizobium sp. M14) was able to grow on minimal salt medium using arsenite as a source of energy, and was able to release arsenic from arsenopyrite. Two strains (Shewanella sp. O23S and Aeromonas sp. O23A) isolated from bottom sediments were able to grow in the absence of oxygen, by As (V) respiration coupled with lactate oxidation. Based on arsenic metabolic activity of isolated bacteria two different mechanisms of arsenic mobilization from natural minerals (arsenopyrite FeAsS) and secondary ferrous arsenate minerals (scorodite FeAsO4) were proposed.


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