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Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment

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A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Molecular Toxicology".

Deadline for manuscript submissions: closed (31 March 2015) | Viewed by 93771

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Special Issue Editors

Prof. Ji-Dong Gu

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Guest Editor

School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
Interests: microbial community and processes in degradation and transformation of organic and inorganic pollutants; microbial diversity and community contributing to carbon and nitrogen cycles; biodeterioration and protection of cultural heritage

Prof. Xiaoke Hu

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Guest Editor

Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, Shandong 264003, China
Interests: microbial remediation of crude oil; microbial loop; microbial interactions; biogeochemistry

Special Issue Information

Dear Colleagues,

Hydrocarbons and metals/metalloids are common environmental pollutants, and information on their transformation and detoxification in ecosystems is crucial to mitigation, remediation and management. Oil spills, a major source of hydrocarbons released into the ecosystems as an example, are a result of undesirable practices in drilling, production, transportation and associated refinery operations dealing with petroleum products. More than two thirds of all large and medium sized oil spills have occurred in coastal or inland waters. A better understanding on the fate of hydrocarbons in oil spills, and mitigation and remediation, requires knowledge on the physical, chemical, biological and ecotoxicological processes involved. Removal strategies using scientific information currently available and a deeper understanding on the processes involved would enhance the mitigation and management of spill more effectively. With the rapid development and industrialization of developing countries, e.g. China and others, imported petroleum and refinery products are the cornerstone of their economy and transportation of petroleum over oceans increases the risk of oil spills, posing greater environmental risk to densely populated coastal areas and also ecosystem health. The fate of hydrocarbons under both aerobic and anaerobic conditions should be closely examined and actively discussed regarding the directions of research and innovative means for future management of them.

Similarly, metals/metalloids extracted from ores for manufacturing purposes are widely used and are also released into the environment through industrialization and urbanization. Metals/metalloids are common contaminants in water, soil and wastewater sludge, posing a threat and risk to drinking water and produces from land and ocean. Therefore, it is important to review the current practices and develop innovative approaches to deal with both hydrocarbons and metals/metalloids with the state of the art knowledge available. This Special Issue on “Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment” will select research papers on:

(1)   understanding the dynamic physical processes of the coastal oceans affecting the transport and fate of hydrocarbons and metals/metalloids;
(2)   elucidating the chemistry of oil and dispersants, and the ecosystem and environmental response to oil and dispersants;
(3)   clarifying the physical, chemical and biological processes contributing to the degradation/transformation and dissipation of hydrocarbons and metals/metalloids in ecosystem; and
(4)   revealing the ecotoxicology of hydrocarbons and metals/metalloids and ecosystem health.

Prof. Ji-Dong Gu
Prof. Xiaoke Hu
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. There is an Article Processing Charge (APC) for publication in this open access journal. For details about the APC please see here. Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

oil spill
hydrocarbons
metals
metalloids
transport
dispersion
abiotic degradation
biological degradation and transformation
metabolism
dissipation
ecotoxicology

Published Papers (13 papers)

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Research

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788 KiB

Open AccessArticle

The Role of CzcRS Two-Component Systems in the Heavy Metal Resistance of Pseudomonas putida X4

by Pulin Liu, Xi Chen, Qiaoyun Huang and Wenli Chen

Int. J. Mol. Sci. 2015, 16(8), 17005-17017; https://doi.org/10.3390/ijms160817005 - 27 Jul 2015

Cited by 15 | Viewed by 5058

Abstract

The role of different czcRS genes in metal resistance and the cross-link between czcRS and czcCBA in Pseudomonas putida X4 were studied to advance understanding of the mechanisms by which P. putida copes with metal stress. Similar to P. putida KT2440, two complete czcRS1 and czcRS2 two-component systems, as well as a czcR3 without the corresponding sensing component were amplified in P. putida X4. The histidine kinase genes czcS1 and czcS2 were inactivated and fused to lacZ by homologous recombination. The lacZ fusion assay revealed that Cd²⁺ and Zn²⁺ caused a decrease in the transcription of czcRS1, whereas Cd²⁺ treatment enhanced the transcription of czcRS2. The mutation of different czcRSs showed that all czcRSs are necessary to facilitate full metal resistance in P. putida X4. A putative gene just downstream of czcR3 is related to metal ion resistance, and its transcription was activated by Zn²⁺. Data from quantitative real-time polymerase chain reaction (qRT-PCR) strongly suggested that czcRSs regulate the expression of czcCBA, and a cross-link exists between different czcRSs. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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3577 KiB

Open AccessArticle

A Comparative Study on the Biosorption of Cd²⁺ onto Paecilomyces lilacinus XLA and Mucoromycote sp. XLC

by Lu Xia, Xingjian Xu, Wei Zhu, Qiaoyun Huang and Wenli Chen

Int. J. Mol. Sci. 2015, 16(7), 15670-15687; https://doi.org/10.3390/ijms160715670 - 10 Jul 2015

Cited by 55 | Viewed by 5839

Abstract

The filamentous fungi XLA and XLC isolated from Cd-contaminated soil were identified morphologically and phylogenetically as Paecilomyces lilacinus and Mucoromycote sp., respectively. The minimum inhibitory concentrations (MICs) of Cd²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cr³⁺ and Cr⁶⁺ in minimum mineral (MM) medium agar plates were 29,786, 2945, 9425, 5080, 1785 and 204 mg·L⁻¹ for XLA and 11,240, 884, 9100, 2540, 3060 and 51 mg·L⁻¹ for XLC, respectively. Favorable biosorption conditions for adsorption of Cd²⁺ by the tested fungi were investigated. Efficient performances of the biosorbents were described using Langmuir isotherm model, and the predicted maximum biosorption capacities for Cd²⁺ were 77.61 mg·g⁻¹ of XLA and 79.67 mg·g⁻¹of XLC. Experiments on desorption potential of biosorbents validated their efficacy at a large scale. Results showed that XLA obtained a desorption rate of 84.7% by 2% EDTA and XLC gained a desorption rate of 78.9% by 0.1 M HCl. Analysis by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) suggested that groups of C–N, COO– for XLA and C–N, CH₂ and phosphate for XLC were the dominant binding sites for Cd²⁺ biosorption. Our results indicated that the fungus XLA, rather than XLC, could potentially be used as an inexpensive, eco-friendly and effective bioremediation agent for the removal of Cd²⁺ from wastewater. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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Open AccessArticle

Evaluation of the Interactions between Water Extractable Soil Organic Matter and Metal Cations (Cu(II), Eu(III)) Using Excitation-Emission Matrix Combined with Parallel Factor Analysis

by Jing Wei, Lu Han, Jing Song and Mengfang Chen

Int. J. Mol. Sci. 2015, 16(7), 14464-14476; https://doi.org/10.3390/ijms160714464 - 25 Jun 2015

Cited by 15 | Viewed by 5503

Abstract

The objectives of this study were to evaluate the binding behavior of Cu(II) and Eu(III) with water extractable organic matter (WEOM) in soil, and assess the competitive effect of the cations. Excitation-emission matrix (EEM) fluorescence spectrometry was used in combination with parallel factor analysis (PARAFAC) to obtain four WEOM components: fulvic-like, humic-like, microbial degraded humic-like, and protein-like substances. Fluorescence titration experiments were performed to obtain the binding parameters of PARAFAC-derived components with Cu(II) and Eu(III). The conditional complexation stability constants (logK_M) of Cu(II) with the four components ranged from 5.49 to 5.94, and the Eu(III) logK_M values were between 5.26 to 5.81. The component-specific binding parameters obtained from competitive binding experiments revealed that Cu(II) and Eu(III) competed for the same binding sites on the WEOM components. These results would help understand the molecular binding mechanisms of Cu(II) and Eu(III) with WEOM in soil environment. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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1990 KiB

Open AccessArticle

Shewanella sp. O23S as a Driving Agent of a System Utilizing Dissimilatory Arsenate-Reducing Bacteria Responsible for Self-Cleaning of Water Contaminated with Arsenic

by Lukasz Drewniak, Robert Stasiuk, Witold Uhrynowski and Aleksandra Sklodowska

Int. J. Mol. Sci. 2015, 16(7), 14409-14427; https://doi.org/10.3390/ijms160714409 - 25 Jun 2015

Cited by 18 | Viewed by 6244

Abstract

The purpose of this study was a detailed characterization of Shewanella sp. O23S, a strain involved in arsenic transformation in ancient gold mine waters contaminated with arsenic and other heavy metals. Physiological analysis of Shewanella sp. O23S showed that it is a facultative anaerobe, capable of growth using arsenate, thiosulfate, nitrate, iron or manganite as a terminal electron acceptor, and lactate or citrate as an electron donor. The strain can grow under anaerobic conditions and utilize arsenate in the respiratory process in a broad range of temperatures (10–37 °C), pH (4–8), salinity (0%–2%), and the presence of heavy metals (Cd, Co, Cr, Cu, Mn, Mo, Se, V and Zn). Under reductive conditions this strain can simultaneously use arsenate and thiosulfate as electron acceptors and produce yellow arsenic (III) sulfide (As₂S₃) precipitate. Simulation of As-removal from water containing arsenate (2.5 mM) and thiosulfate (5 mM) showed 82.5% efficiency after 21 days of incubation at room temperature. Based on the obtained results, we have proposed a model of a microbially mediated system for self-cleaning of mine waters contaminated with arsenic, in which Shewanella sp. O23S is the main driving agent. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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1492 KiB

Open AccessArticle

Fungal Community Successions in Rhizosphere Sediment of Seagrasses Enhalus acoroides under PAHs Stress

by Juan Ling, Yanying Zhang, Meilin Wu, Youshao Wang, Junde Dong, Yufeng Jiang, Qingsong Yang and Siquan Zeng

Int. J. Mol. Sci. 2015, 16(6), 14039-14055; https://doi.org/10.3390/ijms160614039 - 18 Jun 2015

Cited by 16 | Viewed by 6203

Abstract

Seagrass meadows represent one of the highest productive marine ecosystems and are of great ecological and economic values. Recently, they have been confronted with worldwide decline. Fungi play important roles in sustaining the ecosystem health as degraders of polycyclic aromatic hydrocarbons (PAHs), but fewer studies have been conducted in seagrass ecosystems. Hence, we investigated the dynamic variations of the fungal community succession under PAH stress in rhizosphere sediment of seagrasses Enhalus acoroides in this study. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), quantitative PCR (qPCR) and a clone library have been employed to analyze the fungal community’s shifts. Sequencing results of DGGE and the clone library showed that the predominant species belong to phyla Ascomycota and Basidiomycota. The abundance of three groups decreased sharply over the incubation period, whereas they demonstrated different fungal diversity patterns. Both the exposure time and the PAH concentrations affected the microbial diversity as assessed by PCR-DGGE analysis. Redundancy analysis (RDA) indicated that significant factors driving community shifts were ammonium and pH (p < 0.05). Significant amounts of the variations (31.1%) were explained by pH and ammonium, illustrating that those two parameters were the most likely ones to influence or be influenced by the fungal communities’ changes. Investigation results also indicated that fungal communities in seagrass meadow were very sensitive to PAH-induced stress and may be used as potential indicators for the PAH contamination. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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1749 KiB

Open AccessArticle

Chromate Reductase YieF from Escherichia coli Enhances Hexavalent Chromium Resistance of Human HepG2 Cells

by Xuan Liu, Gaofeng Wu, Yanli Zhang, Dan Wu, Xiangkai Li and Pu Liu

Int. J. Mol. Sci. 2015, 16(6), 11892-11902; https://doi.org/10.3390/ijms160611892 - 26 May 2015

Cited by 27 | Viewed by 6286

Abstract

Hexavalent chromium (Cr(VI)) is a serious environmental pollutant and human toxicant. Mammalian cells are very sensitive to chromate as they lack efficient chromate detoxifying strategy, e.g., chromate-reducing genes that are widely present in prokaryotes. To test whether introduction of prokaryotic chromate-reducing gene into mammalian cells could render higher chromate resistance, an Escherichia coli chromate-reducing gene yieF was transfected into human HepG2 cells. The expression of yieF was measured in stably transfected cells HepG2-YieF by quantitative RT-PCR and found up-regulated by 3.89-fold upon Cr(VI) induction. In chromate-reducing ability test, HepG2-YieF cells that harbored the reductase showed significantly higher reducing ability of Cr(VI) than HepG2 control cells. This result was further supported by the evidence of increased Cr(VI)-removing ability of crude cell extract of HepG2-YieF. Moreover, HepG2-YieF demonstrated 10% higher viability and decreased expression of GSH synthesizing enzymes under Cr(VI) stress. Subcellular localization of YieF was determined by tracing GFP-YieF fusion protein that was detected in both nucleus and cytoplasm by laser confocal microscopy. Altogether, this study successfully demonstrated that the expression of a prokaryotic Cr(VI)-reducing gene yieF endowed mammalian cell HepG2 with enhanced chromate resistance, which brought new insight of Cr(VI) detoxification in mammalian cells. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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1299 KiB

Open AccessArticle

High-Throughput Screening for a Moderately Halophilic Phenol-Degrading Strain and Its Salt Tolerance Response

by Zhi-Yan Lu, Xiao-Jue Guo, Hui Li, Zhong-Zi Huang, Kuang-Fei Lin and Yong-Di Liu

Int. J. Mol. Sci. 2015, 16(6), 11834-11848; https://doi.org/10.3390/ijms160611834 - 25 May 2015

Cited by 16 | Viewed by 6381

Abstract

A high-throughput screening system for moderately halophilic phenol-degrading bacteria from various habitats was developed to replace the conventional strain screening owing to its high efficiency. Bacterial enrichments were cultivated in 48 deep well microplates instead of shake flasks or tubes. Measurement of phenol concentrations was performed in 96-well microplates instead of using the conventional spectrophotometric method or high-performance liquid chromatography (HPLC). The high-throughput screening system was used to cultivate forty-three bacterial enrichments and gained a halophilic bacterial community E3 with the best phenol-degrading capability. Halomonas sp. strain 4-5 was isolated from the E3 community. Strain 4-5 was able to degrade more than 94% of the phenol (500 mg·L⁻¹ starting concentration) over a range of 3%–10% NaCl. Additionally, the strain accumulated the compatible solute, ectoine, with increasing salt concentrations. PCR detection of the functional genes suggested that the largest subunit of multicomponent phenol hydroxylase (LmPH) and catechol 1,2-dioxygenase (C12O) were active in the phenol degradation process. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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827 KiB

Open AccessArticle

Promotion of Ni²⁺ Removal by Masking Toxicity to Sulfate-Reducing Bacteria: Addition of Citrate

by Junwei Qian, Xiaoyu Zhu, Yong Tao, Yan Zhou, Xiaohong He and Daping Li

Int. J. Mol. Sci. 2015, 16(4), 7932-7943; https://doi.org/10.3390/ijms16047932 - 09 Apr 2015

Cited by 13 | Viewed by 5914

Abstract

The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni²⁺ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni²⁺-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni²⁺ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni²⁺ and acetate. The NiS precipitate was then formed, and Ni²⁺ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni²⁺ toxicity to SRB and improves the removal of Ni²⁺, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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4089 KiB

Open AccessArticle

Analysis of Bacterial and Archaeal Communities along a High-Molecular-Weight Polyacrylamide Transportation Pipeline System in an Oil Field

by Cai-Yun Li, Jing-Yan Li, Serge Maurice Mbadinga, Jin-Feng Liu, Ji-Dong Gu and Bo-Zhong Mu

Int. J. Mol. Sci. 2015, 16(4), 7445-7461; https://doi.org/10.3390/ijms16047445 - 02 Apr 2015

Cited by 17 | Viewed by 7882

Abstract

Viscosity loss of high-molecular-weight partially hydrolyzed polyacrylamide (HPAM) solution was observed in a water injection pipeline before being injected into subterranean oil wells. In order to investigate the possible involvement of microorganisms in HPAM viscosity loss, both bacterial and archaeal community compositions of four samples collected from different points of the transportation pipeline were analyzed using PCR-amplification of the 16S rRNA gene and clone library construction method together with the analysis of physicochemical properties of HPAM solution and environmental factors. Further, the relationship between environmental factors and HPAM properties with microorganisms were delineated by canonical correspondence analysis (CCA). Diverse bacterial and archaeal groups were detected in the four samples. The microbial community of initial solution S1 gathered from the make-up tank is similar to solution S2 gathered from the first filter, and that of solution S3 obtained between the first and the second filter is similar to that of solution S4 obtained between the second filter and the injection well. Members of the genus Acinetobacter sp. were detected with high abundance in S3 and S4 in which HPAM viscosity was considerably reduced, suggesting that they likely played a considerable role in HPAM viscosity loss. This study presents information on microbial community diversity in the HPAM transportation pipeline and the possible involvement of microorganisms in HPAM viscosity loss and biodegradation. The results will help to understand the microbial community contribution made to viscosity change and are beneficial for providing information for microbial control in oil fields. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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742 KiB

Open AccessArticle

Combined Toxic Effects of Heavy Metals and Antibiotics on a Pseudomonas fluorescens Strain ZY2 Isolated from Swine Wastewater

by Yan Zhou, Yan-Bin Xu, Jia-Xin Xu, Xiao-Hua Zhang, Shi-Hui Xu and Qing-Ping Du

Int. J. Mol. Sci. 2015, 16(2), 2839-2850; https://doi.org/10.3390/ijms16022839 - 27 Jan 2015

Cited by 54 | Viewed by 7592

Abstract

A Pseudomonas fluorescens strain ZY2, isolated from swine wastewater, was used to investigate the synergistic effects of five heavy metals (Pb, Cu, Zn, Cr(VI) and Hg) on bacterial resistance to antibiotics. Results indicate that the combined effects of antibiotic type, heavy metal type and concentration were significant (p < 0.01). Cross-resistance to Hg and antibiotics was the most noticeable. Moreover, the resistance to Hg and cefradine or amoxicillin, and Cr and amoxicillin were synergistic for low heavy metal concentrations, and turned antagonistic with increasing concentrations, while the resistances to Cr or Cu and cefradine, Pb or Cu and amoxicillin, Cu and norfloxacin showed reverse effects. In addition, resistance to Zn and amoxicillin were always synergetic, while resistance to Pb and cefradine or norfloxacin, Cr or Hg and norfloxacin as well as all the heavy metals and tetracycline were antagonistic. These results indicate that bacterial resistance to antibiotics can be affected by the type and concentration of co-exposed heavy metals and may further threaten people’s health and ecological security severely via horizontal gene transfer. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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742 KiB

Open AccessArticle

Bioaccumulation of Arsenic Species in Rays from the Northern Adriatic Sea

by Zdenka Šlejkovec, Anja Stajnko, Ingrid Falnoga, Lovrenc Lipej, Darja Mazej, Milena Horvat and Jadran Faganeli

Int. J. Mol. Sci. 2014, 15(12), 22073-22091; https://doi.org/10.3390/ijms151222073 - 01 Dec 2014

Cited by 27 | Viewed by 6477

Abstract

The difference in arsenic concentration and speciation between benthic (Pteromylaeus bovinus, Myliobatis aquila) and pelagic rays (Pteroplatytrygon violacea) from the northern Adriatic Sea (Gulf of Trieste) in relation to their size (age) was investigated. High arsenic concentrations were found in both groups with tendency of more efficient arsenic accumulation in benthic species, particularly in muscle (32.4 to 362 µg·g⁻¹ of total arsenic). This was attributed to species differences in arsenic access, uptake and retention. In liver most arsenic was present in a form of arsenobetaine, dimethylarsinic acid and arsenoipids, whereas in muscle mainly arsenobetaine was found. The good correlations between total arsenic/arsenobetaine and size reflect the importance of accumulation of arsenobetaine with age. Arsenobetaine is an analogue of glycine betaine, a known osmoregulator in marine animals and both are very abundant in mussels, representing an important source of food for benthic species P. bovinus and M. aquila. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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Review

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2975 KiB

Open AccessReview

Ecotoxicogenomic Approaches for Understanding Molecular Mechanisms of Environmental Chemical Toxicity Using Aquatic Invertebrate, Daphnia Model Organism

by Hyo Jeong Kim, Preeyaporn Koedrith and Young Rok Seo

Int. J. Mol. Sci. 2015, 16(6), 12261-12287; https://doi.org/10.3390/ijms160612261 - 29 May 2015

Cited by 86 | Viewed by 13658

Abstract

Due to the rapid advent in genomics technologies and attention to ecological risk assessment, the term “ecotoxicogenomics” has recently emerged to describe integration of omics studies (i.e., transcriptomics, proteomics, metabolomics, and epigenomics) into ecotoxicological fields. Ecotoxicogenomics is defined as study of an entire set of genes or proteins expression in ecological organisms to provide insight on environmental toxicity, offering benefit in ecological risk assessment. Indeed, Daphnia is a model species to study aquatic environmental toxicity designated in the Organization for Economic Co-operation and Development’s toxicity test guideline and to investigate expression patterns using ecotoxicology-oriented genomics tools. Our main purpose is to demonstrate the potential utility of gene expression profiling in ecotoxicology by identifying novel biomarkers and relevant modes of toxicity in Daphnia magna. These approaches enable us to address adverse phenotypic outcomes linked to particular gene function(s) and mechanistic understanding of aquatic ecotoxicology as well as exploration of useful biomarkers. Furthermore, key challenges that currently face aquatic ecotoxicology (e.g., predicting toxicant responses among a broad spectrum of phytogenetic groups, predicting impact of temporal exposure on toxicant responses) necessitate the parallel use of other model organisms, both aquatic and terrestrial. By investigating gene expression profiling in an environmentally important organism, this provides viable support for the utility of ecotoxicogenomics. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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1911 KiB

Open AccessReview

Chemical Structure, Property and Potential Applications of Biosurfactants Produced by Bacillus subtilis in Petroleum Recovery and Spill Mitigation

by Jin-Feng Liu, Serge Maurice Mbadinga, Shi-Zhong Yang, Ji-Dong Gu and Bo-Zhong Mu

Int. J. Mol. Sci. 2015, 16(3), 4814-4837; https://doi.org/10.3390/ijms16034814 - 03 Mar 2015

Cited by 108 | Viewed by 9995

Abstract

Lipopeptides produced by microorganisms are one of the five major classes of biosurfactants known and they have received much attention from scientific and industrial communities due to their powerful interfacial and biological activities as well as environmentally friendly characteristics. Microbially produced lipopeptides are a series of chemical structural analogues of different families and, among them, 26 families covering about 90 lipopeptide compounds have been reported in the last two decades. This paper reviews the chemical structural characteristics and molecular behaviors of surfactin, one of the representative lipopeptides of the 26 families. In particular, two novel surfactin molecules isolated from cell-free cultures of Bacillus subtilis HSO121 are presented. Surfactins exhibit strong self-assembly ability to form sphere-like micelles and larger aggregates at very low concentrations. The amphipathic and surface properties of surfactins are related to the existence of the minor polar and major hydrophobic domains in the three 3-D conformations. In addition, the application potential of surfactin in bioremediation of oil spills and oil contaminants, and microbial enhanced oil recovery are discussed. Full article

(This article belongs to the Special Issue Microbial Metabolism of Toxic Organic Pollutants and Transformation of Metals/Metalloids and Ecotoxicity Assessment)

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