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Sun L, Zhou Y, Wang C, Nie Y, Xu A, Wu L. Multi-generation reproductive toxicity of RDX and the involved signal pathways in Caenorhabditis elegans. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 260:115074. [PMID: 37257349 DOI: 10.1016/j.ecoenv.2023.115074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/21/2023] [Accepted: 05/24/2023] [Indexed: 06/02/2023]
Abstract
As one of the most frequently used explosives, hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) can cause persistent pollution in the environment, leading to the potential ecological threat crossing the generations. In this study, we employed Caenorhabditis elegans to explore the toxic effects of RDX on the parental and offspring worms and the involved signaling pathways. Exposure up to 1000 ng/mL of RDX produced a significant increase in reactive oxygen species (ROS) production, germ cell apoptosis, and decrease in eggs laid. Various mutants were used to demonstrate the RDX-induced apoptosis signaling pathway, and the metabolism of RDX in the nematodes was found related to cytochrome P450 and GST through RNA sequencing. Exposure of parental worms to RDX produced significant reproductive toxicity in F1 and F2, but was recovered in F3 and F4. The transgenerational effects were associated with the decreased expression of met-2, spr-5, and set-2. Our findings revealed the signaling pathways related to the reproductive toxicity caused by RDX in C. elegans and their future generations, which provided the basis for further exploration of the ecological risks of energetic compounds in the environment.
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Affiliation(s)
- Lingyan Sun
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China
| | - Yanping Zhou
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China
| | - Chunyan Wang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China
| | - Yaguang Nie
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China.
| | - An Xu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China; Key Laboratory of High Magnetic Field and Ion Beam Physical Biology, Chinese Academy of Sciences; Anhui Province Key Laboratory of Environmental Toxicology and Pollution Control Technology, High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, Anhui 230031, PR China.
| | - Lijun Wu
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, PR China
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Barbosa J, Asselman J, Janssen CR. Synthesizing the impact of sea-dumped munition and related chemicals on humans and the environment. MARINE POLLUTION BULLETIN 2023; 187:114601. [PMID: 36652858 DOI: 10.1016/j.marpolbul.2023.114601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 06/17/2023]
Abstract
Marine environments are globally impacted by vast quantities of munition disposed following both World Wars. Dumped munitions contain conventional explosives, chemicals warfare agents as well as a variety of metals. Field monitoring studies around marine dumpsites report the presence of munition constituents in water and sediment samples. The growing interest and developments in the ocean as a new economic frontier underline the need to remediate existing dumpsites. Here, we provide a comprehensive assessment of the magnitude and potential risks associated with marine munition dumpsites. An overview of the global distribution of dumpsites identifying the most impacted areas is provided, followed by the currently available data on the detection of munition constituents in environmental samples and evidence of their toxic potential to human and environmental health. Finally, existing data gaps are identified and future research needs promoting better understanding of the impact of the dumped material on the marine environment suggested.
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Affiliation(s)
- João Barbosa
- Laboratory for Environmental Toxicology and Aquatic Ecology, GhEnToxLab, Ghent University, Belgium; Blue Growth Research Lab, Ghent University, Bluebridge, Wetenschapspark 1, 8400 Ostend, Belgium.
| | - Jana Asselman
- Blue Growth Research Lab, Ghent University, Bluebridge, Wetenschapspark 1, 8400 Ostend, Belgium
| | - Colin R Janssen
- Laboratory for Environmental Toxicology and Aquatic Ecology, GhEnToxLab, Ghent University, Belgium; Blue Growth Research Lab, Ghent University, Bluebridge, Wetenschapspark 1, 8400 Ostend, Belgium
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3
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Li H, Yang H, Zhou M, Wei T, Zhou Y. Synergistic Effects of IMX-104 Components in Membrane Absorption: A Computational Study. ACS OMEGA 2022; 7:40892-40899. [PMID: 36406561 PMCID: PMC9670098 DOI: 10.1021/acsomega.2c03886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
New insensitive munitions such as IMX-104 formulations are being developed to improve the safety suffering from accidental stimulations. Experimental data indicated the synergistic toxicity of 2,4-dinitroanisole (DNAN) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in IMX-104, which increased the concern about its environmental and health threats. Indeed, little is known about the synergistic mechanism. Here, we investigated the membrane absorption of DNAN and RDX as the first step toward uncovering synergistic toxicity. The permeability coefficient, transmembrane time, and liposome-water partition coefficient were calculated by the umbrella sampling technique. The results show that component RDX in the IMX-104 formulation promotes the membrane absorption of another more toxic component DNAN, suggesting that the synergistic toxicity effect of IMX-104 may emerge from their membrane adsorption stage. In detail, the integrating free-energy curves show that DNAN, RDX, or their mixture in membranes would promote subsequent molecules passing through membranes. For the mixture of DNAN and RDX, RDX was absorbed by the membrane before DNAN. Postabsorbed DNAN tends to stay around RDX, which is due to the strong van der Waals (VDW) interaction between them. RDX stabilized under phospholipid headgroups limits the overflow of DNAN from the membrane, which results in 11% more absorption of DNAN by the membrane than in the case of the pure DNAN system.
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Dehkordi NR, Knapp M, Compton P, Fernandez LA, Alshawabkeh AN, Larese-Casanova P. Degradation of Dissolved RDX, NQ, and DNAN by Cathodic Processes in an Electrochemical Flow-Through Reactor. JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING 2022; 10:107865. [PMID: 37124117 PMCID: PMC10147348 DOI: 10.1016/j.jece.2022.107865] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Both legacy munitions compounds (e.g., RDX) and new insensitive high explosives (e.g. DNAN, NQ) are being manufactured and utilized concurrently, and there exists a need for wastewater treatment systems that are able to degrade both classes of explosives. Electrochemical systems offer treatment possibilities using inexpensive materials and no chemical additions. Electrochemically induced removal of RDX, NQ, and DNAN were separately studied within an electrochemical plug flow reactor hosting a stainless steel (SS) cathode and downstream Ti/MMO anode. Varying wire mesh cathodes and operating conditions were evaluated in an effort to identify the optimal cathode material, to determine the relative contributions of cathodically-induced removal processes, to shorten time to steady-state removal conditions, and to find practical ranges of operating conditions. Applied current allowed the cathode to support munitions removal mainly by direct reduction at the cathode surface, and the secondary reactions of cathodically-induced alkaline hydrolysis and catalytic hydrogenation by adsorbed H on Ni-containing cathode surfaces might contribute to some munitions degradation. The optimal cathode material was identified as SS grade 316, possibly due to its superior Ni content and lack of corrosion protection coating. Higher current, longer cathode length, and smaller mesh pore sizes resulted in slightly greater removal extents and shorter acclimation times to steady state removal conditions, but there are practical upper limits to these properties. Higher Ni content within SS improved RDX and NQ removal but does not affect DNAN removal. Prolonged use of SS grade 316 showed no debilitating changes in electrical performance or chemical content.
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Affiliation(s)
| | | | | | | | | | - Philip Larese-Casanova
- Corresponding Author: Philip Larese-Casanova, Department of Civil & Environmental Engineering, Northeastern University, 400 Snell Engineering, Boston, Massachusetts, 02115, USA, Phone: +1-617-373-2899; Fax: +1-617-373-4419,
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5
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Compton P, Dehkordi NR, Knapp M, Fernandez LA, Alshawabkeh AN, Larese-Casanova P. Heterogeneous Fenton-Like Catalysis of Electrogenerated H2O2 for Dissolved RDX Removal. FRONTIERS IN CHEMICAL ENGINEERING 2022; 4. [DOI: 10.3389/fceng.2022.864816] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
New insensitive high explosives pose great challenges to conventional explosives manufacturing wastewater treatment processes and require advanced methods to effectively and efficiently mineralize these recalcitrant pollutants. Oxidation processes that utilize the fundamental techniques of Fenton chemistry optimized to overcome conventional limitations are vital to provide efficient degradation of these pollutants while maintaining cost-effectiveness and scalability. In this manner, utilizing heterogeneous catalysts and in-situ generated H2O2 to degrade IHEs is proposed. For heterogeneous catalyst optimization, varying the surface chemistry of activated carbon for use as a catalyst removes precipitation complications associated with iron species in Fenton chemistry while including removal by adsorption. Activated carbon impregnated with 5% MnO2 in the presence of H2O2 realized a high concentration of hydroxyl radical formation - 140 μM with 10 mM H2O2 - while maintaining low cost and relative ease of synthesis. This AC-Mn5 catalyst performed effectively over a wide pH range and in the presence of varying H2O2 concentrations with a sufficient effective lifetime. In-situ generation of H2O2 removes the logistical and economic constraints associated with external H2O2, with hydrophobic carbon electrodes utilizing generated gaseous O2 for 2-electron oxygen reduction reactions. In a novel flow-through reactor, gaseous O2 is generated on a titanium/mixed metal oxide anode with subsequent H2O2 electrogeneration on a hydrophobic microporous-layered carbon cloth cathode. This reactor is able to electrogenerate 2 mM H2O2 at an optimized current intensity of 150 mA and over a wide range of flow rates, influent pH values, and through multiple iterations. Coupling these two optimization methods realizes the production of highly oxidative hydroxyl radicals by Fenton-like catalysis of electrogenerated H2O2 on the surface of an MnO2-impregnated activated carbon catalyst. This method incorporates electrochemically induced oxidation of munitions in addition to removal by adsorption while maintaining cost-effectiveness and scalability. It is anticipated this platform holds great promise to eliminate analogous contaminants.
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6
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Gust KA, Indest KJ, Lotufo G, Everman SJ, Jung CM, Ballentine ML, Hoke AV, Sowe B, Gautam A, Hammamieh R, Ji Q, Barker ND. Genomic investigations of acute munitions exposures on the health and skin microbiome composition of leopard frog (Rana pipiens) tadpoles. ENVIRONMENTAL RESEARCH 2021; 192:110245. [PMID: 32987006 DOI: 10.1016/j.envres.2020.110245] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
Natural communities of microbes inhabiting amphibian skin, the skin microbiome, are critical to supporting amphibian health and disease resistance. To enable the pro-active health assessment and management of amphibians on Army installations and beyond, we investigated the effects of acute (96h) munitions exposures to Rana pipiens (leopard frog) tadpoles and the associated skin microbiome, integrated with RNAseq-based transcriptomic responses in the tadpole host. Tadpoles were exposed to the legacy munition 2,4,6-trinitrotoluene (TNT), the new insensitive munition (IM) formulation, IMX-101, and the IM constituents nitroguinidine (NQ) and 1-methyl-3-nitroguanidine (MeNQ). The 96h LC50 values and 95% confidence intervals were 2.6 (2.4, 2.8) for ΣTNT and 68.2 (62.9, 73.9) for IMX-101, respectively. The NQ and MeNQ exposures caused no significant impacts on survival in 96h exposures even at maximum exposure levels of 3560 and 5285 mg/L, respectively. However, NQ and MeNQ, as well as TNT and IMX-101 exposures, all elicited changes in the tadpole skin microbiome profile, as evidenced by significantly increased relative proportions of the Proteobacteria with increasing exposure concentrations, and significantly decreased alpha-diversity in the NQ exposure. The potential for direct effects of munitions exposure on the skin microbiome were observed including increased abundance of munitions-tolerant phylogenetic groups, in addition to possible indirect effects on microbial flora where transcriptional responses suggestive of changes in skin mucus-layer properties, antimicrobial peptide production, and innate immune factors were observed in the tadpole host. Additional insights into the tadpole host's transcriptional response to munitions exposures indicated that TNT and IMX-101 exposures significantly enriched transcriptional expression within type-I and type-II xenobiotic metabolism pathways, where dose-responsive increases in expression were observed. Significant enrichment and increased transcriptional expression of heme and iron binding functions in the TNT exposures served as likely indicators of known mechanisms of TNT toxicity including hemolytic anemia and methemoglobinemia. The significant enrichment and dose-responsive decrease in transcriptional expression of cell cycle pathways in the IMX-101 exposures was consistent with previous observations in fish, while significant enrichment of immune-related function in response to NQ exposure were consistent with potential immune suppression at the highest NQ exposure concentration. Finally, the MeNQ exposures elicited significantly decreased transcriptional expression of keratin 16, type I, a gene likely involved in keratinization processes in amphibian skin. Overall, munitions showed the potential to alter tadpole skin microbiome composition and affect transcriptional profiles in the amphibian host, some suggestive of potential impacts on host health and immune status relevant to disease susceptibility.
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Affiliation(s)
- Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | - Karl J Indest
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | - Guilherme Lotufo
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | | | - Carina M Jung
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | - Mark L Ballentine
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | - Allison V Hoke
- Medical Readiness Systems Biology, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA; ORISE fellow, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Bintu Sowe
- Medical Readiness Systems Biology, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA; ORISE fellow, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Aarti Gautam
- Medical Readiness Systems Biology, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Rasha Hammamieh
- Medical Readiness Systems Biology, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
| | - Qing Ji
- Bennett Aerospace, Cary, NC, USA.
| | - Natalie D Barker
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
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7
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Lotufo GR, Gust KA, Ballentine ML, Moores LC, Kennedy AJ, Barker ND, Ji Q, Chappell P. Comparative Toxicological Evaluation of UV-Degraded versus Parent-Insensitive Munition Compound 1-Methyl-3-Nitroguanidine in Fathead Minnow. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2020; 39:612-622. [PMID: 31845397 DOI: 10.1002/etc.4647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/09/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
The US Army is replacing traditional munitions with insensitive munitions resistant to accidental detonation. Although the parent insensitive munition compound nitroguanidine (NQ) is generally not acutely toxic at concentrations >1000 mg/L in aquatic exposures, products formed by intensive ultraviolet (UV) degradation resulted in multiple-order of magnitude increases in toxicity. A methylated congener of NQ, 1-methyl-3-nitroguanidine (MeNQ), is also being assessed for potential use in insensitive munition explosive formulations; therefore, the present study investigated the hazard of parent versus UV-degraded MeNQ using fathead minnows (Pimephales promelas). Although up to 716 mg/L parent MeNQ caused no significant mortality or effects on growth in larval P. promelas fish in 7-d exposures, a similar concentration of MeNQ subjected to UV treatment resulted in 85% mortality. The UV treatment degraded only 3.3% of the MeNQ (5800 mg/L stock, UV-treated for 6 h), indicating that MeNQ degradation products have potentially high toxicity. The parent MeNQ exposure caused significantly decreased transcriptional expression of genes within the significantly enriched insulin metabolic pathway, suggesting antagonism of bioenergetics pathways, which complements observed, although nonsignificant, decreases in body weight. Significant differential transcriptional expression in the UV-degraded MeNQ treatments resulted in significant enrichment of pathways and functions related to the cell cycle, as well as erythrocyte function involved in O2 /CO2 exchange. These functions represent potential mechanistic sources of increased toxicity observed in the UV-degraded MeNQ exposures, which are distinct from previously observed mechanisms underlying increased toxicity of UV-degraded NQ in fish. Environ Toxicol Chem 2020;39:612-622. © 2019 SETAC.
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Affiliation(s)
- Guilherme R Lotufo
- US Army, Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi
| | - Kurt A Gust
- US Army, Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi
| | - Mark L Ballentine
- US Army, Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi
| | - Lee C Moores
- US Army, Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi
| | - Alan J Kennedy
- US Army, Engineer Research and Development Center, Environmental Laboratory, Vicksburg, Mississippi
| | | | - Qing Ji
- Bennett Aerospace, Cary, North Carolina, USA
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8
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Moores LC, Kennedy AJ, May L, Jordan SM, Bednar AJ, Jones SJ, Henderson DL, Gurtowski L, Gust KA. Identifying degradation products responsible for increased toxicity of UV-Degraded insensitive munitions. CHEMOSPHERE 2020; 240:124958. [PMID: 31726587 DOI: 10.1016/j.chemosphere.2019.124958] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/21/2019] [Accepted: 09/23/2019] [Indexed: 06/10/2023]
Abstract
Degradation of insensitive munitions (IMs) by ultraviolet (UV) light has become a topic of concern following observations that some UV-degradation products have increased toxicity relative to parent compounds in aquatic organisms. The present investigation focused on the Army's IM formulation, IMX-101, which is composed of three IM constituents: 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ). The IM constituents and IMX-101 were irradiated in a UV photo-reactor and then administered to Daphnia pulex in acute (48 h) exposures comparing toxicities relative to the parent materials. UV-degradation of DNAN had little effect on mortality whereas mortality for UV-degraded NTO and NQ (and associated degradation products) increased by factors of 40.3 and 1240, respectively, making UV-degraded NQ the principle driver of toxicity when IMX-101 is UV-degraded. Toxicity investigations for specific products formed during UV-degradation of NQ, confirmed greater toxicity than the parent NQ for degradation products including guanidine, nitrite, ammonia, nitrosoguanidine, and cyanide. Summation of the individual toxic units for the complete set of individually measured UV-degradation products identified for NQ only accounted for 25% of the overall toxicity measured in the exposures to the UV-degraded NQ product mixture. From these toxic unit calculations, nitrite followed by CN- were the principal degradation products contributing to toxicity. Given the underestimation of toxicity using the sum toxic units for the individually measured UV-degradation products of NQ, we conclude that: (1) other unidentified NQ degradation products contributed principally to toxicity and/or (2) synergistic toxicological interactions occurred among the NQ degradation product mixture that exacerbated toxicity.
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Affiliation(s)
- Lee C Moores
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA.
| | - Alan J Kennedy
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Lauren May
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Shinita M Jordan
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Anthony J Bednar
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Stacy J Jones
- HX5, 212 Eglin Parkway SE, Ft, Walton Beach, FL, 32548, USA
| | - David L Henderson
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Luke Gurtowski
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
| | - Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, 3909 Halls Ferry Road, Vicksburg, MS, 39180, USA
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9
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Gust KA, Lotufo GR, Stanley JK, Wilbanks MS, Chappell P, Barker ND. Transcriptomics provides mechanistic indicators of mixture toxicology for IMX-101 and IMX-104 formulations in fathead minnows (Pimephales promelas). AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2018; 199:138-151. [PMID: 29625381 DOI: 10.1016/j.aquatox.2018.03.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 03/16/2018] [Accepted: 03/17/2018] [Indexed: 06/08/2023]
Abstract
Within the US military, new insensitive munitions (IMs) are rapidly replacing conventional munitions improving safety from unintended detonation. Toxicity data for IM chemicals are expanding rapidly, however IM constituents are typically deployed in mixture formulations, and very little is known about their mixture toxicology. In the present study we sought to characterize the mixture effects and toxicology of the two predominant IM formulations IMX-101 and IMX-104 in acute (48 h) larval fathead minnow (Pimephales promelas) exposures. IMX-101 consists of a mixture of 2,4-dinitroanisole (DNAN), 3-nitro-1,2,4-triazol-5-one (NTO), and nitroguanidine (NQ) while IMX-104 is composed of DNAN, NTO, and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). DNAN was the most potent constituent in IMX-101 eliciting an LC50 of 36.1 mg/L, whereas NTO and NQ did not elicit significant mortality in exposures up to 1040 and 2640 mg/L, respectively. Toxic unit calculations indicated that IMX-101 elicited toxicity representative of the component concentration of DNAN within the mixture. Toxicogenomic responses for the individual constituents of IMX-101 indicated unique transcriptional expression and functional responses characteristic of: oxidative stress, impaired energy metabolism, tissue damage and inflammatory responses in DNAN exposures; impaired steroid biosynthesis and developmental cell-signaling in NQ exposures; and altered mitogen-activated protein kinase signaling in NTO exposures. Transcriptional responses to the IMX-101 mixture were driven by the effects of DNAN where expression and functional responses were nearly identical comparing DNAN alone versus the fractional equivalent of DNAN within IMX-101. Given that each individual constituent of the IMX-101 mixture elicited unique functional responses, and NTO and NQ did not interact with DNAN within the IMX-101 mixture exposure, the overall toxicity and toxicogenomic responses within acute exposures to the IMX-101 formulation are indicative of "independent" mixture toxicology. Alternatively, in the IMX-104 exposure both DNAN and RDX were each present at concentrations sufficient to elicit lethality (RDX LC50 = 28.9 mg/L). Toxic-unit calculations for IMX-104 mixture formulation exposures indicated slight synergistic toxicity (ΣTU LC50 = 0.82, 95% confidence interval = 0.73-0.90). Unique functional responses relative to DNAN were observed in the IMX-104 exposure including responses characteristic of RDX exposure. Based on previous transcriptomics responses to acute RDX exposures in fathead minnow larvae, we hypothesize that the potentially synergistic responses within the IMX-104 mixture are related to interactive effects of each DNAN and RDX on oxidative stress mitigation pathways.
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Affiliation(s)
- Kurt A Gust
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA.
| | - Guilherme R Lotufo
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA
| | - Jacob K Stanley
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA; Stanley Environmental Consulting, Waynesboro, MS, USA
| | - Mitchell S Wilbanks
- U.S. Army Engineer Research and Development Center, Environmental Laboratory, Vicksburg, MS, USA
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Bulutoglu B, Haghpanah J, Campbell E, Banta S. Engineered Biomolecular Recognition of RDX by Using a Thermostable Alcohol Dehydrogenase as a Protein Scaffold. Chembiochem 2018; 19:247-255. [PMID: 29165861 DOI: 10.1002/cbic.201700539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Indexed: 11/09/2022]
Abstract
There are many biotechnology applications that would benefit from simple, stable proteins with engineered biomolecular recognition. Here, we explored the hypothesis that a thermostable alcohol dehydrogenase (AdhD from Pyrococcus furiosus) could be engineered to bind a small molecule instead of a cofactor or molecules involved in the catalytic transition state. We chose the explosive molecule 1,3,5-trinitro-1,3,5-triazine (royal demolition explosive, RDX) as a proof-of-concept. Its low solubility in water was exploited for immobilization for biopanning by using ribosome display. Docking simulations were used to identify two potential binding sites in AdhD, and a randomized library focused on tyrosine or serine mutations was used to determine that RDX was binding in the substrate binding pocket of the enzyme. A fully randomized binding pocket library was selected, and affinity maturation by error-prone PCR led to the identification of a mutant (EP-16) that gained the ability to bind RDX with an affinity of (73±11) μm. These results underscore the way in which thermostable enzymes can be useful scaffolds for expanding the biomolecular recognition toolbox.
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Affiliation(s)
- Beyza Bulutoglu
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, NY, 10027, USA.,Present address: The Center for Engineering in Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, 02114, USA
| | - Jennifer Haghpanah
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, NY, 10027, USA
| | - Elliot Campbell
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, NY, 10027, USA.,Present address: Center for Advanced Biotechnology and Medicine, Rutgers University, Piscataway, NY, 08854, USA
| | - Scott Banta
- Department of Chemical Engineering, Columbia University, 500 West 120th Street, Room 801, New York, NY, 10027, USA
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Corrales J, Kristofco LA, Steele WB, Saari GN, Kostal J, Williams ES, Mills M, Gallagher EP, Kavanagh TJ, Simcox N, Shen LQ, Melnikov F, Zimmerman JB, Voutchkova-Kostal AM, Anastas PT, Brooks BW. Toward the Design of Less Hazardous Chemicals: Exploring Comparative Oxidative Stress in Two Common Animal Models. Chem Res Toxicol 2016; 30:893-904. [PMID: 27750016 DOI: 10.1021/acs.chemrestox.6b00246] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Sustainable molecular design of less hazardous chemicals presents a potentially transformative approach to protect public health and the environment. Relationships between molecular descriptors and toxicity thresholds previously identified the octanol-water distribution coefficient, log D, and the HOMO-LUMO energy gap, ΔE, as two useful properties in the identification of reduced aquatic toxicity. To determine whether these two property-based guidelines are applicable to sublethal oxidative stress (OS) responses, two common aquatic in vivo models, the fathead minnow (Pimephales promelas) and zebrafish (Danio rerio), were employed to examine traditional biochemical biomarkers (lipid peroxidation, DNA damage, and total glutathione) and antioxidant gene activation following exposure to eight structurally diverse industrial chemicals (bisphenol A, cumene hydroperoxide, dinoseb, hydroquinone, indene, perfluorooctanoic acid, R-(-)-carvone, and tert-butyl hydroperoxide). Bisphenol A, cumene hydroperoxide, dinoseb, and hydroquinone were consistent inducers of OS. Glutathione was the most consistently affected biomarker, suggesting its utility as a sensitivity response to support the design of less hazardous chemicals. Antioxidant gene expression (changes in nrf2, gclc, gst, and sod) was most significantly (p < 0.05) altered by R-(-)-carvone, cumene hydroperoxide, and bisphenol A. Results from the present study indicate that metabolism of parent chemicals and the role of their metabolites in molecular initiating events should be considered during the design of less hazardous chemicals. Current empirical and computational findings identify the need for future derivation of sustainable molecular design guidelines for electrophilic reactive chemicals (e.g., SN2 nucleophilic substitution and Michael addition reactivity) to reduce OS related adverse outcomes in vivo.
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Affiliation(s)
- Jone Corrales
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
| | - Lauren A Kristofco
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
| | - W Baylor Steele
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
| | - Gavin N Saari
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
| | - Jakub Kostal
- Department of Chemistry, George Washington University , Washington, D.C. 20052, United States
| | - E Spencer Williams
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
| | - Margaret Mills
- Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Evan P Gallagher
- Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Nancy Simcox
- Department of Environmental and Occupational Health Sciences, University of Washington , Seattle, Washington 98195, United States
| | - Longzhu Q Shen
- Center for Green Chemistry and Green Engineering, Yale University , New Haven, Connecticut 06520, United States
| | - Fjodor Melnikov
- Center for Green Chemistry and Green Engineering, Yale University , New Haven, Connecticut 06520, United States
| | - Julie B Zimmerman
- Center for Green Chemistry and Green Engineering, Yale University , New Haven, Connecticut 06520, United States.,Department of Chemical and Environmental Engineering, Yale University , New Haven, Connecticut 06520, United States
| | | | - Paul T Anastas
- Center for Green Chemistry and Green Engineering, Yale University , New Haven, Connecticut 06520, United States
| | - Bryan W Brooks
- Department of Environmental Science, Baylor University , Waco, Texas 76798, United States
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12
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Collier ZA, Gust KA, Gonzalez-Morales B, Gong P, Wilbanks MS, Linkov I, Perkins EJ. A weight of evidence assessment approach for adverse outcome pathways. Regul Toxicol Pharmacol 2016; 75:46-57. [DOI: 10.1016/j.yrtph.2015.12.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 12/22/2015] [Accepted: 12/22/2015] [Indexed: 01/07/2023]
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13
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Abstract
Systems biology and synthetic biology are emerging disciplines which are becoming increasingly utilised in several areas of bioscience. Toxicology is beginning to benefit from systems biology and we suggest in the future that is will also benefit from synthetic biology. Thus, a new era is on the horizon. This review illustrates how a suite of innovative techniques and tools can be applied to understanding complex health and toxicology issues. We review limitations confronted by the traditional computational approaches to toxicology and epidemiology research, using polycyclic aromatic hydrocarbons (PAHs) and their effects on adverse birth outcomes as an illustrative example. We introduce how systems toxicology (and their subdisciplines, genomic, proteomic, and metabolomic toxicology) will help to overcome such limitations. In particular, we discuss the advantages and disadvantages of mathematical frameworks that computationally represent biological systems. Finally, we discuss the nascent discipline of synthetic biology and highlight relevant toxicological centred applications of this technique, including improvements in personalised medicine. We conclude this review by presenting a number of opportunities and challenges that could shape the future of these rapidly evolving disciplines.
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14
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Krewski D, Westphal M, Andersen ME, Paoli GM, Chiu WA, Al-Zoughool M, Croteau MC, Burgoon LD, Cote I. A framework for the next generation of risk science. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:796-805. [PMID: 24727499 PMCID: PMC4123023 DOI: 10.1289/ehp.1307260] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 04/09/2014] [Indexed: 05/19/2023]
Abstract
OBJECTIVES In 2011, the U.S. Environmental Protection Agency initiated the NexGen project to develop a new paradigm for the next generation of risk science. METHODS The NexGen framework was built on three cornerstones: the availability of new data on toxicity pathways made possible by fundamental advances in basic biology and toxicological science, the incorporation of a population health perspective that recognizes that most adverse health outcomes involve multiple determinants, and a renewed focus on new risk assessment methodologies designed to better inform risk management decision making. RESULTS The NexGen framework has three phases. Phase I (objectives) focuses on problem formulation and scoping, taking into account the risk context and the range of available risk management decision-making options. Phase II (risk assessment) seeks to identify critical toxicity pathway perturbations using new toxicity testing tools and technologies, and to better characterize risks and uncertainties using advanced risk assessment methodologies. Phase III (risk management) involves the development of evidence-based population health risk management strategies of a regulatory, economic, advisory, community-based, or technological nature, using sound principles of risk management decision making. CONCLUSIONS Analysis of a series of case study prototypes indicated that many aspects of the NexGen framework are already beginning to be adopted in practice.
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Affiliation(s)
- Daniel Krewski
- McLaughlin Centre for Population Health Risk Assessment, University of Ottawa, Ottawa, Ontario, Canada
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15
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Garcia-Reyero N, Ekman DR, Habib T, Villeneuve DL, Collette TW, Bencic DC, Ankley GT, Perkins EJ. Integrated approach to explore the mechanisms of aromatase inhibition and recovery in fathead minnows (Pimephales promelas). Gen Comp Endocrinol 2014; 203:193-202. [PMID: 24704562 DOI: 10.1016/j.ygcen.2014.03.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Revised: 03/10/2014] [Accepted: 03/12/2014] [Indexed: 12/20/2022]
Abstract
Aromatase, a member of the cytochrome P450 superfamily, is a key enzyme in estradiol synthesis that catalyzes the aromatization of androgens into estrogens in ovaries. Here, we used an integrated approach to assess the mechanistic basis of the direct effects of aromatase inhibition, as well as adaptation and recovery processes in fish. We exposed female fathead minnows (Pimephales promelas) via the water to 30 μg/L of a model aromatase inhibitor, fadrozole, during 8 days (exposure phase). Fish were then held in clean water for 8 more days (recovery phase). Samples were collected at 1, 2, 4, and 8 days of both the exposure and the recovery phases. Transcriptomics, metabolomics, and network inference were used to understand changes and infer connections at the transcript and metabolite level in the ovary. Apical endpoints directly indicative of endocrine function, such as plasma estradiol, testosterone, and vitellogenin levels were also measured. An integrated analysis of the data revealed changes in gene expression consistent with increased testosterone in fadrozole-exposed ovaries. Metabolites such as glycogen and taurine were strongly correlated with increased testosterone levels. Comparison of in vivo and ex vivo steroidogenesis data suggested the accumulation of steroidogenic enzymes, including aromatase, as a mechanism to compensate for aromatase inhibition.
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Affiliation(s)
- Natàlia Garcia-Reyero
- Institute for Genomics Biocomputing and Biotechnology, Mississippi State University, Starkville, MS 39759, USA.
| | - Drew R Ekman
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Athens, GA 30605, USA
| | - Tanwir Habib
- Badger Technical Services, San Antonio, TX 78216, USA
| | - Daniel L Villeneuve
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA
| | - Timothy W Collette
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Athens, GA 30605, USA
| | - David C Bencic
- US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposures Research Division, Cincinnati, OH, USA
| | - Gerald T Ankley
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, MN, USA
| | - Edward J Perkins
- US Army Engineer Research and Development Center, Vicksburg, MS 39180, USA
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16
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Davis M, Boekelheide K, Boverhof DR, Eichenbaum G, Hartung T, Holsapple MP, Jones TW, Richard AM, Watkins PB. The new revolution in toxicology: The good, the bad, and the ugly. Ann N Y Acad Sci 2013; 1278:11-24. [DOI: 10.1111/nyas.12086] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Myrtle Davis
- Toxicology and Pharmacology Branch, Developmental Therapeutics Program Division of Cancer Treatment and Diagnosis; The National Cancer Institute, National Institutes of Health; Bethesda; Maryland
| | - Kim Boekelheide
- Deparment of Pathology and Laboratory Medicine; Brown University; Providence; Rhode Island
| | - Darrell R. Boverhof
- Toxicology and Environmental Research and Consulting; The Dow Chemical Company; Midland; Michigan
| | - Gary Eichenbaum
- Department of Drug Safety Science; Johnson & Johnson Pharmaceutical R&D, LLC; Raritan; NJ
| | - Thomas Hartung
- Department of Environmental Health Sciences. Johns Hopkins Bloomberg School of Public Health; Baltimore; Maryland
| | | | - Thomas W. Jones
- Department of Toxicology and Pathology; Elil Lilly and Company; Indianapolis; Indiana
| | - Ann M. Richard
- National Center for Computational Toxicology; Environmental Protection Agency, Research Triangle Park; North Carolina
| | - Paul B. Watkins
- Institute for Drug Safety Sciences; Hamner University of North Carolina, Research Triangle Park; North Carolina
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