Environmental fate of pyrethroids in urban and suburban stream sediments and the appropriateness of Hyalella azteca model in determining ecological risk.

PubMed

Palmquist, Katherine; Fairbrother, Anne; Salatas, Johanna; Guiney, Patrick D

2011-07-01

According to several recent studies using standard acute Hyalella azteca sediment bioassays, increased pyrethroid use in urban and suburban regions in California has resulted in the accumulation of toxic concentrations of pyrethroids in sediments of area streams and estuaries. However, a critical review of the literature indicates that this is likely an overestimation of environmental risk. Hyalella azteca is consistently the most susceptible organism to both aqueous and sediment-associated pyrethroid exposures when compared to a suite of other aquatic taxa. In some cases, H. azteca LC50 values are less than the community HC10 values, suggesting that the amphipod is an overly conservative model for community- or ecosystem-level impacts of sediment-associated pyrethroids. Further, as a model for responses of field populations of H. azteca, the laboratory bioassays considerably overestimate exposure, because the amphipod is more appropriately characterized as an epibenthic organism, not a true sediment dweller; H. azteca preferentially inhabit aquatic macrophytes, periphyton mats, and leaf litter, which drastically reduces their exposure to contaminated sediments. Sediment-bound pyrethroids are transported via downstream washing of fine particulates resulting in longer range transport but also more efficient sequestration of the chemical. In addition, site-specific variables such as sediment organic carbon content, grain size, temperature, and microbial activity alter pyrethroid bioavailability, degradation, and toxicity on a microhabitat scale. The type and source of the carbon in particular, influences the pyrethroid sequestering ability of sediments. The resulting irregular distribution of pyrethroids in stream sediments suggests that sufficient nonimpacted habitat may exist as refugia for resident sediment-dwelling organisms for rapid recolonization to occur. Given these factors, we argue that the amphipod model provides, at best, a screening level assessment of pyrethroid impacts and can correctly identify those sediments not toxic to benthic organisms but cannot accurately predict where sediments will be toxic. Copyright © 2011 SETAC.

INNOVATIVE IN-SITU REMEDIATION OF CONTAMINATED SEDIMENTS FOR SIMULTANEOUS CONTROL OF CONTAMINATION AND EROSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knox, A; Michael Paller, M; Danny D. Reible, D

2007-11-28

New technologies are needed that neutralize contaminant toxicity and control physical transport mechanisms that mobilize sediment contaminants. The last 12 months of this comprehensive project investigated the use of combinations of sequestering agents to develop in situ active sediment caps that stabilize mixtures of contaminants and act as a barrier to mechanical disturbance under a broad range of environmental conditions. Efforts focused on the selection of effective sequestering agents for use in active caps, the composition of active caps, and the effects of active cap components on contaminant bioavailability and retention. Results from this project showed that phosphate amendments, somemore » organoclays, and the biopolymer, chitosan, were very effective at removing metals from both fresh and salt water. These amendments also exhibited high retention (80% or more) of most metals indicating reduced potential for remobilization to the water column. Experiments on metal speciation and retention in contaminated sediment showed that apatite and organoclay can immobilize a broad range of metals under both reduced and oxidized conditions. These studies were followed by sequential extractions to evaluate the bioavailability and retention of metals in treated sediments. Metal fractions recovered in early extraction steps are more likely to be bioavailable and were termed the Potentially Mobile Fraction (PMF). Less bioavailable fractions collected in later extraction steps were termed the Recalcitrant Factor (RF). Apatite and organoclay reduced the PMF and increased the RF for several elements, especially Pb, Zn, Ni, Cr, and Cd. Empirically determined partitioning coefficients and modeling studies were used to assess the retention of organic contaminants on selected sequestering agents. Organoclays exhibited exceptionally high sorption of polycyclic aromatic hydrocarbons as indicated by a comparison of K{sub d} values among 12 amendments. These results suggested that organoclays have high potential for controlling organic contaminants. Measured partitioning coefficients were used to model the time required for a contaminant to penetrate sediment caps composed of organoclay. The results showed that a thin layer of highly sorptive organoclay can lead to very long migration times, perhaps longer than the expected lifetime of the contaminant in the sediment environment. A one-dimensional numerical model was used to examine the diffusion of metals through several cap material based on measured and assumed material and transport properties. These studies showed that active caps composed of apatite or organoclay have the potential to delay contaminant breakthrough due to diffusion by hundreds of years or more compared with passive caps composed of sand. Advectively dominated column experiments are currently underway to define effective sorption related retardation factors in promising amendments for various hydrophobic organic compounds. Upon completion of these experiments, advection transient models will be used to estimate the time required for the breakthrough of various contaminants in caps composed of different experimental materials. Biopolymer products for inclusion in active caps were evaluated on the basis of resistance to biodegradation, sorption capacity for organic and inorganic contaminants, and potential for erosion control. More than 20 biopolymer products were evaluated resulting in the selection of chitosan/guar gum cross-linked with borax and xanthan/chitosan cross-linked with calcium chloride for inclusion in active caps to produce a barrier that resists mechanical disturbance. A process was developed for coating sand with cross-linked biopolymers to provide a means for delivery to the sediment surface. Properties of biopolymer coated sand such as carbon fraction (indicating biopolymer coverage), porosity, bulk density, and biodegradability have been evaluated, and experiments are currently underway to assess the resistance of biopolymer coated sand to erosion. Although the ability of active cap materials to remediate contaminants has been emphasized in this study, it is also important to ensure that these materials do not have deleterious effects on the environment. Therefore, promising amendments were evaluated for toxicity using 10 day sediment toxicity tests, the standardized Toxicity Characteristic Leaching Procedure (TCLP), and measurement of metal concentrations in aqueous extracts from the amendments. Metal concentrations were below TCLP limits, EPA ambient water quality criteria, and other ecological screening values These results showed that apatite, organoclay, and biopolymer coated sand do not release metals. The sediment toxicity tests indicated that apatite and biopolymer coated sand are unlikely to adversely affect benthic organisms, even when used in high concentrations.« less

Suppression of polyglutamine toxicity by a Drosophila homolog of myeloid leukemia factor 1.

PubMed

Kazemi-Esfarjani, Parsa; Benzer, Seymour

2002-10-01

The toxicity of an abnormally long polyglutamine [poly(Q)] tract within specific proteins is the molecular lesion shared by Huntington's disease (HD) and several other hereditary neurodegenerative disorders. By a genetic screen in Drosophila, devised to uncover genes that suppress poly(Q) toxicity, we discovered a Drosophila homolog of human myeloid leukemia factor 1 (MLF1). Expression of the Drosophila homolog (dMLF) ameliorates the toxicity of poly(Q) expressed in the eye and central nervous system. In the retina, whether endogenously or ectopically expressed, dMLF co-localized with aggregates, suggesting that dMLF alone, or through an intermediary molecular partner, may suppress toxicity by sequestering poly(Q) and/or its aggregates.

Synthesis of organically templated nanoporous tin (II/IV) phosphate for radionuclide and metal sequestration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wellman, Dawn M.; Mattigod, Shas V.; Parker, Kent E.

2006-03-20

Nanoporous tin (II/IV) phosphate materials, with spherical morphology, have been synthesized using cetyltrimethylammonium chloride (CH3(CH2)15N(CH3)3Cl) as the surfactant. The structure of the material is stable at 500°C; however, partial oxidation of the material occurs with redox conversion of Sn2+ to Sn4+, resulting in a mixed Sn(II)/ Sn(IV) material. Preliminary batch contact studies were conducted to assess the effectiveness of nanoporous tin phosphate, NP-SnPO, in sequestering redox sensitive metals and radionuclides, technetium(VII), neptunium(V), thorium(IV), and a toxic metal, chromium(VI), from aqueous matrices. Results indicate tin (II) phosphate removed > 95% of all contaminants investigated from solution.

Sodium ion channel alkaloid resistance does not vary with toxicity in aposematic Dendrobates poison frogs: An examination of correlated trait evolution

PubMed Central

Wang, Ian J.

2018-01-01

Spatial heterogeneity in the strength or agents of selection can lead to geographic variation in ecologically important phenotypes. Many dendrobatid frogs sequester alkaloid toxins from their diets and often exhibit fixed mutations at NaV1.4, a voltage-gated sodium ion channel associated with alkaloid toxin resistance. Yet previous studies have noted an absence of resistance mutations in individuals from several species known to sequester alkaloid toxins, suggesting possible intraspecific variation for alkaloid resistance in these species. Toxicity and alkaloid profiles vary substantially between populations in several poison frog species (genus Dendrobates) and are correlated with variation in a suite of related traits such as aposematic coloration. If resistance mutations are costly, due to alterations of channel gating properties, we expect that low toxicity populations will have reduced frequencies and potentially even the loss of resistance alleles. Here, we examine whether intraspecific variation in toxicity in three dendrobatid frogs is associated with intraspecific variation in alleles conferring toxin resistance. Specifically, we examine two species that display marked variation in toxicity throughout their native ranges (Dendrobates pumilio and D. granuliferus) and one species with reduced toxicity in its introduced range (D. auratus). However, we find no evidence for population-level variation in alkaloid resistance at NaV1.4. In fact, contrary to previous studies, we found that alkaloid resistance alleles were not absent in any populations of these species. All three species exhibit fixed alkaloid resistance mutations throughout their ranges, suggesting that these mutations are maintained even when alkaloid sequestration is substantially reduced. PMID:29534110

Novel endotoxin-sequestering compounds with terephthalaldehyde-bis-guanylhydrazone scaffolds.

PubMed

Khownium, Kriangsak; Wood, Stewart J; Miller, Kelly A; Balakrishna, Rajalakshmi; Nguyen, Thuan B; Kimbrell, Matthew R; Georg, Gunda I; David, Sunil A

2006-03-01

We have shown that lipopolyamines bind to the lipid A moiety of lipopolysaccharide, a constituent of Gram-negative bacterial membranes, and neutralize its toxicity in animal models of endotoxic shock. In an effort to identify non-polyamine scaffolds with similar endotoxin-recognizing features, we had observed an unusually high frequency of hits containing guanylhydrazone scaffolds in high-throughput screens. We now describe the syntheses and preliminary structure-activity relationships in a homologous series of bis-guanylhydrazone compounds decorated with hydrophobic functionalities. These first-generation compounds bind and neutralize lipopolysaccharide with a potency comparable to that of polymyxin B, a peptide antibiotic known to sequester LPS.

Exploring the erodibility of sediments and harmful algal blooms in the Gulf of Maine

USGS Publications Warehouse

Butman, Bradford; Dickhudt, Patrick J.; Keafer, Bruce A.

2012-01-01

Investigators at the U.S. Geological Survey (USGS) are cooperating with scientists at Woods Hole Oceanographic Institution (WHOI) to investigate harmful algal blooms along the New England coast in the Gulf of Maine. These blooms are caused by cysts of the dinoflagellate Alexandrium fundyense that overwinter in the bottom sediments and germinate in spring. Depending on conditions such as temperature, light, nutrient levels, and currents, these single-celled organismscan create a bloom along the coast, called ‘red tides.’Shellfish that have ingested these cells in sufficient concentration can become toxic to humans and require that the shellfisheries be closed. After the spring bloom, the organisms form cysts that sink to the sea floor and are sequestered in the bottom sediments over the winter.

Effect of Microbial inoculation in combating the aluminium toxicity effect on growth of Zea mays.

PubMed

Arora, P; Singh, G; Tiwari, A

2017-07-31

The present study is aimed at improving the aluminium tolerance in maize crop employing the potential of microbial inoculants in conferring resistance to these toxicities via production of certain chelating compounds like siderophores, exopolysachharides and organic acids. Acid soils have now-a-days become one of the key factors for limiting growth of many agriculturally important crops. Aluminium  is one of the major elements present in acid soils and is mainly responsible for toxicity in the soil. This aluminium is rapidly soluble in soil water and hence absorbed by plant roots under conditions where soil pH is below 5. This toxicity leads to severe root growth inhibition, thereby limiting the production of maize crops. It was observed that use of microbial inoculums can be helpful in elimination of these toxic compounds and prevent the inhibition of root growth . It was found that the soils contaminated with aluminium toxicity decreased the root length of maize plant significantly by 65% but Bacillus and Burkholderia inoculation increased this root length significantly by 1.4- folds and 2- folds respectively thereby combating the effect of aluminium toxicity. Aluminium concentration was found maximum in roots of plants which were grown under aluminium stress condition. But this aluminium accumulation decreased ̴ 2-folds when Burkholderia was used as seed inoculants under aluminium stress conditions. Also, at 60mM aluminium accumulation, phosphorus solubilisation in roots was found to be increased upto 30% on Burkholderia inoculation. However, Bacillus inoculation didn't show any significant difference in either of the case. Thus, the inoculation of seeds with Burkholderia isolates could prove to be a boon in sequestering aluminium toxicity in Zea mays.

Hydrogen sulfide alleviates mercury toxicity by sequestering it in roots or regulating reactive oxygen species productions in rice seedlings.

PubMed

Chen, Zhen; Chen, Moshun; Jiang, Ming

2017-02-01

Soil mercury (Hg) contamination is a major factor that affects agricultural yield and food security. Hydrogen sulfide (H 2 S) plays multifunctional roles in mediating a variety of responses to abiotic stresses. The effects of exogenous H 2 S on rice (Oryza sativa var 'Nipponbare') growth and metabolism under mercuric chloride (HgCl 2 ) stress were investigated in this study. Either 100 or 200 μM sodium hydrosulfide (NaHS, a donor of H 2 S) pretreatment improved the transcription of bZIP60, a membrane-associated transcription factor, and then enhanced the expressions of non-protein thiols (NPT) and metallothioneins (OsMT-1) to sequester Hg in roots and thus inhibit Hg transport to shoots. Meanwhile, H 2 S promoted seedlings growth significantly even in the presences of Hg and superoxide dismutase (SOD, EC 1.15.1.1) or catalase (CAT, EC 1.11.1.6) inhibitors, diethyldithiocarbamate (DDC) or 3-amino-1,2,4-triazole (AT). H 2 S might act as an antioxidant to inhibit or scavenge reactive oxygen species (ROS) productions for maintaining the lower MDA and H 2 O 2 levels, and thereby preventing oxidative damages. All these results indicated H 2 S effectively alleviated Hg toxicity by sequestering it in roots or by regulating ROS in seedlings and then thus significantly promoted rice growth. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Toxicity of nanomaterials

PubMed Central

Sharifi, Shahriar; Behzadi, Shahed; Laurent, Sophie; Forrest, M. Laird; Stroeve, Pieter

2015-01-01

Nanoscience has matured significantly during the last decade as it has transitioned from bench top science to applied technology. Presently, nanomaterials are used in a wide variety of commercial products such as electronic components, sports equipment, sun creams and biomedical applications. There are few studies of the long-term consequences of nanoparticles on human health, but governmental agencies, including the United States National Institute for Occupational Safety and Health and Japan’s Ministry of Health, have recently raised the question of whether seemingly innocuous materials such as carbon-based nanotubes should be treated with the same caution afforded known carcinogens such as asbestos. Since nanomaterials are increasing a part of everyday consumer products, manufacturing processes, and medical products, it is imperative that both workers and end-users be protected from inhalation of potentially toxic NPs. It also suggests that NPs may need to be sequestered into products so that the NPs are not released into the atmosphere during the product’s life or during recycling. Further, non-inhalation routes of NP absorption, including dermal and medical injectables, must be studied in order to understand possible toxic effects. Fewer studies to date have addressed whether the body can eventually eliminate nanomaterials to prevent particle build-up in tissues or organs. This critical review discusses the biophysicochemical properties of various nanomaterials with emphasis on currently available toxicology data and methodologies for evaluating nanoparticle toxicity. PMID:22170510

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Re-directing bacterial microcompartment systems to enhance recombinant expression of lysis protein E from bacteriophage ΦX174 in Escherichia coli

DOE PAGES

Yung, Mimi C.; Bourguet, Feliza A.; Carpenter, Timothy S.; ...

2017-04-26

Recombinant expression of toxic proteins remains a challenging problem. Furthermore, one potential method to shield toxicity and thus improve expression of these proteins is to encapsulate them within protein compartments to sequester them away from their targets. Many bacteria naturally produce so-called bacterial microcompartments (BMCs) in which enzymes comprising a biosynthetic pathway are encapsulated in a proteinaeous shell, which is in part thought to shield the cells from the toxicity of reaction intermediates. As a proof-of-concept, we attempted to encapsulate toxic, lysis protein E (E) from bacteriophage ΦX174 inside recombinant BMCs to enhance its expression and achieve higher yields duringmore » downstream purification.« less

Amending metal contaminated mine soil with biochars to sequester metals and improve plant growth cover

EPA Science Inventory

There are numerous mine spoil sites in the U.S. Pacific Northwest that contain highly acidic, heavy metal-laden soils, which limits establishment of a soil-stabilizing plant cover. Biochars may be a suitable soil amendment to reduce toxic metals, improve soil fertility, soil wa...

In-situ observation for growth of hierarchical metal-organic frameworks and their self-sequestering mechanism for gas storage

NASA Astrophysics Data System (ADS)

Hyo Park, Jung; Min Choi, Kyung; Joon Jeon, Hyung; Jung Choi, Yoon; Ku Kang, Jeung

2015-07-01

Although structures with the single functional constructions and micropores were demonstrated to capture many different molecules such as carbon dioxide, methane, and hydrogen with high capacities at low temperatures, their feeble interactions still limit practical applications at room temperature. Herein, we report in-situ growth observation of hierarchical pores in pomegranate metal-organic frameworks (pmg-MOFs) and their self-sequestering storage mechanism, not observed for pristine MOFs. Direct observation of hierarchical pores inside the pmg-MOF was evident by in-situ growth X-ray measurements while self-sequestering storage mechanism was revealed by in-situ gas sorption X-ray analysis and molecular dynamics simulations. The results show that meso/macropores are created at the early stage of crystal growth and then enclosed by micropore crystalline shells, where hierarchical pores are networking under self-sequestering mechanism to give enhanced gas storage. This pmg-MOF gives higher CO2 (39%) and CH4 (14%) storage capacity than pristine MOF at room temperature, in addition to fast kinetics with robust capacity retention during gas sorption cycles, thus giving the clue to control dynamic behaviors of gas adsorption.

SEQUESTERING AGENTS FOR ACTIVE CAPS - REMEDIATION OF METALS AND ORGANICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knox, A; Michael Paller, M; Danny D. Reible, D

2007-05-10

This research evaluated organoclays, zeolites, phosphates, and a biopolymer as sequestering agents for inorganic and organic contaminants. Batch experiments were conducted to identify amendments and mixtures of amendments for metal and organic contaminants removal and retention. Contaminant removal was evaluated by calculating partitioning coefficients. Metal retention was evaluated by desorption studies in which residue from the removal studies was extracted with 1 M MgCl{sub 2} solution. The results indicated that phosphate amendments, some organoclays, and the biopolymer, chitosan, were very effective sequestering agents for metals in fresh and salt water. Organoclays were very effective sorbents for phenanthrene, pyrene, and benzo(a)pyrene.more » Partitioning coefficients for the organoclays were 3000-3500 ml g{sup -1} for benzo(a)pyrene, 400-450 ml g{sup -1} for pyrene, and 50-70 ml g{sup -1} for phenanthrene. Remediation of sites with a mixture of contaminants is more difficult than sites with a single contaminant because metals and organic contaminants have different fate and transport mechanisms in sediment and water. Mixtures of amendments (e.g., organoclay and rock phosphate) have high potential for remediating both organic and inorganic contaminants under a broad range of environmental conditions, and have promise as components in active caps for sediment remediation.« less

North American prairie wetlands are important nonforested land-based carbon storage sites

USGS Publications Warehouse

Euliss, N.H.; Gleason, R.A.; Olness, A.; McDougal, R.L.; Murkin, H.R.; Robarts, R.D.; Bourbonniere, R.A.; Warner, B.G.

2006-01-01

We evaluated the potential of prairie wetlands in North America as carbon sinks. Agricultural conversion has resulted in the average loss of 10.1 Mg ha- 1 of soil organic carbon on over 16 million ha of wetlands in this region. Wetland restoration has potential to sequester 378 Tg of organic carbon over a 10-year period. Wetlands can sequester over twice the organic carbon as no-till cropland on only about 17% of the total land area in the region. We estimate that wetland restoration has potential to offset 2.4% of the annual fossil CO2 emission reported for North America in 1990. ?? 2005 Elsevier B.V. All rights reserved.

Sodium chloride toxicity and the cellular basis of salt tolerance in halophytes

PubMed Central

Flowers, Timothy J.; Munns, Rana; Colmer, Timothy D.

2015-01-01

Background Halophytes are the flora of saline soils. They adjust osmotically to soil salinity by accumulating ions and sequestering the vast majority of these (generally Na+ and Cl−) in vacuoles, while in the cytoplasm organic solutes are accumulated to prevent adverse effects on metabolism. At high salinities, however, growth is inhibited. Possible causes are: toxicity to metabolism of Na+ and/or Cl− in the cytoplasm; insufficient osmotic adjustment resulting in reduced net photosynthesis because of stomatal closure; reduced turgor for expansion growth; adverse cellular water relations if ions build up in the apoplast (cell walls) of leaves; diversion of energy needed to maintain solute homeostasis; sub-optimal levels of K+ (or other mineral nutrients) required for maintaining enzyme activities; possible damage from reactive oxygen species; or changes in hormonal concentrations. Scope This review discusses the evidence for Na+ and Cl− toxicity and the concept of tissue tolerance in relation to halophytes. Conclusions The data reviewed here suggest that halophytes tolerate cytoplasmic Na+ and Cl− concentrations of 100–200 mm, but whether these ions ever reach toxic concentrations that inhibit metabolism in the cytoplasm or cause death is unknown. Measurements of ion concentrations in the cytosol of various cell types for contrasting species and growth conditions are needed. Future work should also focus on the properties of the tonoplast that enable ion accumulation and prevent ion leakage, such as the special properties of ion transporters and of the lipids that determine membrane permeability. PMID:25466549

Probiotic Lactobacillus rhamnosus Reduces Organophosphate Pesticide Absorption and Toxicity to Drosophila melanogaster

PubMed Central

Trinder, Mark; McDowell, Tim W.; Daisley, Brendan A.; Ali, Sohrab N.; Leong, Hon S.; Sumarah, Mark W.

2016-01-01

ABSTRACT Organophosphate pesticides used in agriculture can pose health risks to humans and wildlife. We hypothesized that dietary supplementation with Lactobacillus, a genus of commensal bacteria, would reduce absorption and toxicity of consumed organophosphate pesticides (parathion and chlorpyrifos [CP]). Several Lactobacillus species were screened for toleration of 100 ppm of CP or parathion in MRS broth based on 24-h growth curves. Certain Lactobacillus strains were unable to reach stationary-phase culture maxima and displayed an abnormal culture morphology in response to pesticide. Further characterization of commonly used, pesticide-tolerant and pesticide-susceptible, probiotic Lactobacillus rhamnosus strain GG (LGG) and L. rhamnosus strain GR-1 (LGR-1), respectively, revealed that both strains could significantly sequester organophosphate pesticides from solution after 24-h coincubations. This effect was independent of metabolic activity, as L. rhamnosus GG did not hydrolyze CP and no difference in organophosphate sequestration was observed between live and heat-killed strains. Furthermore, LGR-1 and LGG reduced the absorption of 100 μM parathion or CP in a Caco-2 Transwell model of the small intestine epithelium. To determine the effect of sequestration on acute toxicity, newly eclosed Drosophila melanogaster flies were exposed to food containing 10 μM CP with or without supplementation with live LGG. Supplementation with LGG simultaneously, but not with administration of CP 3 days prior (prophylactically), mitigated CP-induced mortality. In summary, the results suggest that L. rhamnosus may be useful for reducing toxic organophosphate pesticide exposure via passive binding. These findings could be transferable to clinical and livestock applications due to affordability and practical ability to supplement products with food-grade bacteria. IMPORTANCE The consequences of environmental pesticide pollution due to widespread usage in agriculture and soil leaching are becoming a major societal concern. Although the long-term effects of low-dose pesticide exposure for humans and wildlife remain largely unknown, logic suggests that these chemicals are not aligned with ecosystem health. This observation is most strongly supported by the agricultural losses associated with honeybee population declines, known as colony collapse disorder, in which pesticide usage is a likely trigger. Lactobacilli are bacteria used as beneficial microorganisms in fermented foods and have shown potentials to sequester and degrade environmental toxins. This study demonstrated that commonly used probiotic strains of lactobacilli could sequester, but not metabolize, organophosphate pesticides (parathion and chlorpyrifos). This Lactobacillus-mediated sequestration was associated with decreased intestinal absorption and insect toxicity in appropriate models. These findings hold promise for supplementing human, livestock, or apiary foods with probiotic microorganisms to reduce organophosphate pesticide exposure. PMID:27520820

Soil organic carbon sequestration in cotton production systems of the southeastern United States: a review.

PubMed

Causarano, H J; Franzluebbers, A J; Reeves, D W; Shaw, J N

2006-01-01

Past agricultural management practices have contributed to the loss of soil organic carbon (SOC) and emission of greenhouse gases (e.g., carbon dioxide and nitrous oxide). Fortunately, however, conservation-oriented agricultural management systems can be, and have been, developed to sequester SOC, improve soil quality, and increase crop productivity. Our objectives were to (i) review literature related to SOC sequestration in cotton (Gossypium hirsutum L.) production systems, (ii) recommend best management practices to sequester SOC, and (iii) outline the current political scenario and future probabilities for cotton producers to benefit from SOC sequestration. From a review of 20 studies in the region, SOC increased with no tillage compared with conventional tillage by 0.48 +/- 0.56 Mg C ha(-1) yr(-1) (H(0): no change, p < 0.001). More diverse rotations of cotton with high-residue-producing crops such as corn (Zea mays L.) and small grains would sequester greater quantities of SOC than continuous cotton. No-tillage cropping with a cover crop sequestered 0.67 +/- 0.63 Mg C ha(-1) yr(-1), while that of no-tillage cropping without a cover crop sequestered 0.34 +/- 47 Mg C ha(-1) yr(-1) (mean comparison, p = 0.04). Current government incentive programs recommend agricultural practices that would contribute to SOC sequestration. Participation in the Conservation Security Program could lead to government payments of up to Dollars 20 ha(-1). Current open-market trading of C credits would appear to yield less than Dollars 3 ha(-1), although prices would greatly increase should a government policy to limit greenhouse gas emissions be mandated.

Methods and constructs for expression of foreign proteins in photosynthetic organisms

DOEpatents

Laible, Philip D.; Hanson, Deborah K.

2002-01-01

A method for expressing and purifying foreign proteins in photosynthetic organisms comprising the simultaneous expression of both the heterologous protein and a means for compartmentalizing or sequestering of the protein.

Phytoremediation of ionic and methylmercury pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

2010-04-28

Our long-term goal is to enable highly productive plant species to extract, resist, detoxify, and sequester the toxic elemental pollutants, like the heavy metal mercury. Our current working hypothesis is that transgenic plants controlling the transport, chemical speciation, electrochemical state. volatilization, and aboveground binding of mercury will: a) tolerate mercury and grow rapidly in mercury contaminated environments; b) prevent methylmercury from entering the food chain; c) remove mercury from polluted soil and water; and d) hyperaccumulate mercury in aboveground tissues for later harvest. Progress toward these specific aims is reported: to increase the transport of mercury into roots and tomore » aboveground vegetative organs; to increase biochemical sinks and storage for mercury in leaves; to increase leaf cell vacuolar storage of mercury; and to demonstrate that several stacked transgenes, when functioning in concert, enhance mercury resistance and hyperaccumulation to high levels.« less

Geochemical modulation of bioavailability and toxicity of nitroaromatic compounds to aquatic plants.

PubMed

Roberts, Michael G; Rugh, Clayton L; Li, Hui; Teppen, Brian J; Boyd, Stephen A

2007-03-01

Nitroaromatic compounds (NACs) are prominent soil and sediment contaminants that are strongly adsorbed by smectites at extents that depend on hydration properties of the exchangeable cation. Potassium smectites adsorb nitroaromatics much more strongly than calcium smectites, so that adjustment of K+ versus Ca2+ occupation on cation exchange sites in smectites can be used to modulate the retention and release of nitroaromatics. We suggest that this modulation can be used to advantageously manage the bioavailability and toxicity of NACs during bioremedation. We have measured the toxicity of 2,4-dinitrotoluene (2,4-DNT) to duckweed grown in smectite suspensions and utilized Ca2+/K+ exchange to retain or release 2,4-DNT. Retention by potassium smectite reduced bioavailability and hence toxicity to duckweed. Addition of Ca2+ to replace K+ by ion exchange released adsorbed 2,4-DNT, which is toxic to duckweed. So smectites can be used to sequester or release 2,4-DNT predictably and provide means to control bioavailability and environmental toxicity.

Electrostatic lipid-protein interactions sequester the curli amyloid fold on the lipopolysaccharide membrane surface.

PubMed

Swasthi, Hema M; Mukhopadhyay, Samrat

2017-12-01

Curli is a functional amyloid protein in the extracellular matrix of enteric Gram-negative bacteria. Curli is assembled at the cell surface and consists of CsgA, the major subunit of curli, and a membrane-associated nucleator protein, CsgB. Oligomeric intermediates that accumulate during the lag phase of amyloidogenesis are generally toxic, but the underlying mechanism by which bacterial cells overcome this toxicity during curli assembly at the surface remains elusive. Here, we elucidated the mechanism of curli amyloidogenesis and provide molecular insights into the strategy by which bacteria can potentially bypass the detrimental consequences of toxic amyloid intermediates. Using a diverse range of biochemical and biophysical tools involving circular dichroism, fluorescence, Raman spectroscopy, and atomic force microscopy imaging, we characterized the molecular basis of the interaction of CsgB with a membrane-mimetic anionic surfactant as well as with lipopolysaccharide (LPS) constituting the outer leaflet of Gram-negative bacteria. Aggregation studies revealed that the electrostatic interaction of the positively charged C-terminal region of the protein with a negatively charged head group of surfactant/LPS promotes a protein-protein interaction that results in facile amyloid formation without a detectable lag phase. We also show that CsgB, in the presence of surfactant/LPS, accelerates the fibrillation rate of CsgA by circumventing the lag phase during nucleation. Our findings suggest that the electrostatic interactions between lipid and protein molecules play a pivotal role in efficiently sequestering the amyloid fold of curli on the membrane surface without significant accumulation of toxic oligomeric intermediates. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Injectable nanocarriers for biodetoxification

NASA Astrophysics Data System (ADS)

Leroux, Jean-Christophe

2007-11-01

Hospitals routinely treat patients suffering from overdoses of drugs or other toxic chemicals as a result of illicit drug consumption, suicide attempts or accidental exposures. However, for many life-threatening situations, specific antidotes are not available and treatment is largely based on emptying the stomach, administering activated charcoal or other general measures of intoxication support. A promising strategy for managing such overdoses is to inject nanocarriers that can extract toxic agents from intoxicated tissues. To be effective, the nanocarriers must remain in the blood long enough to sequester the toxic components and/or their metabolites, and the toxin bound complex must also remain stable until it is removed from the bloodstream. Here, we discuss the principles that govern the use of injectable nanocarriers in biodetoxification and review the pharmacological performance of a number of different approaches.

Probiotic Lactobacillus rhamnosus Reduces Organophosphate Pesticide Absorption and Toxicity to Drosophila melanogaster.

PubMed

Trinder, Mark; McDowell, Tim W; Daisley, Brendan A; Ali, Sohrab N; Leong, Hon S; Sumarah, Mark W; Reid, Gregor

2016-10-15

Organophosphate pesticides used in agriculture can pose health risks to humans and wildlife. We hypothesized that dietary supplementation with Lactobacillus, a genus of commensal bacteria, would reduce absorption and toxicity of consumed organophosphate pesticides (parathion and chlorpyrifos [CP]). Several Lactobacillus species were screened for toleration of 100 ppm of CP or parathion in MRS broth based on 24-h growth curves. Certain Lactobacillus strains were unable to reach stationary-phase culture maxima and displayed an abnormal culture morphology in response to pesticide. Further characterization of commonly used, pesticide-tolerant and pesticide-susceptible, probiotic Lactobacillus rhamnosus strain GG (LGG) and L. rhamnosus strain GR-1 (LGR-1), respectively, revealed that both strains could significantly sequester organophosphate pesticides from solution after 24-h coincubations. This effect was independent of metabolic activity, as L. rhamnosus GG did not hydrolyze CP and no difference in organophosphate sequestration was observed between live and heat-killed strains. Furthermore, LGR-1 and LGG reduced the absorption of 100 μM parathion or CP in a Caco-2 Transwell model of the small intestine epithelium. To determine the effect of sequestration on acute toxicity, newly eclosed Drosophila melanogaster flies were exposed to food containing 10 μM CP with or without supplementation with live LGG. Supplementation with LGG simultaneously, but not with administration of CP 3 days prior (prophylactically), mitigated CP-induced mortality. In summary, the results suggest that L. rhamnosus may be useful for reducing toxic organophosphate pesticide exposure via passive binding. These findings could be transferable to clinical and livestock applications due to affordability and practical ability to supplement products with food-grade bacteria. The consequences of environmental pesticide pollution due to widespread usage in agriculture and soil leaching are becoming a major societal concern. Although the long-term effects of low-dose pesticide exposure for humans and wildlife remain largely unknown, logic suggests that these chemicals are not aligned with ecosystem health. This observation is most strongly supported by the agricultural losses associated with honeybee population declines, known as colony collapse disorder, in which pesticide usage is a likely trigger. Lactobacilli are bacteria used as beneficial microorganisms in fermented foods and have shown potentials to sequester and degrade environmental toxins. This study demonstrated that commonly used probiotic strains of lactobacilli could sequester, but not metabolize, organophosphate pesticides (parathion and chlorpyrifos). This Lactobacillus-mediated sequestration was associated with decreased intestinal absorption and insect toxicity in appropriate models. These findings hold promise for supplementing human, livestock, or apiary foods with probiotic microorganisms to reduce organophosphate pesticide exposure. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Mutant Huntingtin Impairs Axonal Trafficking in Mammalian Neurons In Vivo and In Vitro

PubMed Central

Trushina, Eugenia; Dyer, Roy B.; Badger, John D.; Ure, Daren; Eide, Lars; Tran, David D.; Vrieze, Brent T.; Legendre-Guillemin, Valerie; McPherson, Peter S.; Mandavilli, Bhaskar S.; Van Houten, Bennett; Zeitlin, Scott; McNiven, Mark; Aebersold, Ruedi; Hayden, Michael; Parisi, Joseph E.; Seeberg, Erling; Dragatsis, Ioannis; Doyle, Kelly; Bender, Anna; Chacko, Celin; McMurray, Cynthia T.

2004-01-01

Recent data in invertebrates demonstrated that huntingtin (htt) is essential for fast axonal trafficking. Here, we provide direct and functional evidence that htt is involved in fast axonal trafficking in mammals. Moreover, expression of full-length mutant htt (mhtt) impairs vesicular and mitochondrial trafficking in mammalian neurons in vitro and in whole animals in vivo. Particularly, mitochondria become progressively immobilized and stop more frequently in neurons from transgenic animals. These defects occurred early in development prior to the onset of measurable neurological or mitochondrial abnormalities. Consistent with a progressive loss of function, wild-type htt, trafficking motors, and mitochondrial components were selectively sequestered by mhtt in human Huntington's disease-affected brain. Data provide a model for how loss of htt function causes toxicity; mhtt-mediated aggregation sequesters htt and components of trafficking machinery leading to loss of mitochondrial motility and eventual mitochondrial dysfunction. PMID:15340079

Attenuation of Vibrio fischeri quorum sensing using rationally designed polymers.

PubMed

Piletska, Elena V; Stavroulakis, Georgios; Karim, Kal; Whitcombe, Michael J; Chianella, Iva; Sharma, Anant; Eboigbodin, Kevin E; Robinson, Gary K; Piletsky, Sergey A

2010-04-12

A first attempt to attenuate the quorum sensing (QS) of a marine heterotroph microorganism, Vibrio fischeri , using signal molecule-sequestering polymers (SSPs) is presented. A set of rationally designed polymers with affinity toward a signal molecule of V. fischeri , N-(beta-ketocaproyl)-l-homoserine lactone (3-oxo-C6-AHL) was produced. It is reported that computationally designed polymers could sequester a signal molecule of V. fischeri and prevent QS-controlled phenotypes (in this case, bioluminescence) from being up-regulated. It was proven that the attenuation of bioluminescence of V. fischeri was due to sequestration of the signal molecule by specific polymers and not due to the toxicity of polymer or nonspecific depletion of nutrients. The ability to disrupt the bacterial communication using easy to synthesize and chemically inert polymers could provide a new concept for the development of pharmaceuticals and susceptible device coatings such as catheters.

Nano Sponges for Drug Delivery and Medicinal Applications

NASA Technical Reports Server (NTRS)

Tour, James M.; Lucente-Schultz, Rebecca; Leonard, Ashley; Kosynkin, Dimitry V.; Price, Brandi Katherine; Hudson, Jared L.; Conyers, Jodie L., Jr.; Moore, Valerie C.; Casscells, S. Ward; Myers, Jeffrey N.;

Seed chemistry of Sophora chrysophylla (mamane) in relation to diet of specialist avian seed predator Loxioides bailleui (palila) in Hawaii

USGS Publications Warehouse

Banko, P.C.; Cipollini, M.L.; Breton, G.W.; Paulk, E.; Wink, M.; Izhaki, Ido

2002-01-01

This study describes the chemical ecology of a tritrophic interaction among species endemic to the island of Hawaii, USA: a tree (Sophora chrysophylla: mamane), an endangered bird (Loxioides bailleui; palila), and moth larvae (Cydia spp.). Palila and Cydia both specialize on the seed embryos of mamane but avoid eating the seed coats. Palila actively seek out and feed mamane embryos and Cydia larvae to their nestlings. Because mamane embryos contain potentially toxic levels of alkaloids, including broadly toxic quinolizidine alkaloids, and because insects often sequester alkaloids from their food plants, we focus on the questions of why palila forage upon mamane embryos and why they supplement their diet with Cydia larvae. Our data show that mamane embryos contain high amounts of potentially toxic alkaloids, but are well balanced nutritionally and contain lipids, carbohydrates, proteins, amino acids, and minerals at levels that are likely to be sufficient for maintenance and breeding. Mamane seed coats contain lower levels of alkaloids and nutrients, somewhat higher levels of phenolics, and much higher levels of nondigestible fiber. Taken together, these results suggest that palila have evolved tolerance to high levels of alkaloids and that they forage upon embryos primarily because of their availability in the habitat and high nutritional reward. Our data also suggest that Cydia are used by palila because they are readily accessible, nontoxic, and nutritious; the larvae apparently do not sequester alkaloids while feeding upon mamane seeds. Our results are interpreted with respect to the likelihood of current and historical coadaptive responses in this ecologically isolated and simplified island setting.

Protective actions of the vesicular monoamine transporter 2 (VMAT2) in monoaminergic neurons.

PubMed

Guillot, Thomas S; Miller, Gary W

2009-04-01

Vesicular monoamine transporters (VMATs) are responsible for the packaging of neurotransmitters such as dopamine, serotonin, norepinephrine, and epinephrine into synaptic vesicles. These proteins evolved from precursors in the major facilitator superfamily of transporters and are among the members of the toxin extruding antiporter family. While the primary function of VMATs is to sequester neurotransmitters within vesicles, they can also translocate toxicants away from cytosolic sites of action. In the case of dopamine, this dual role of VMAT2 is combined-dopamine is more readily oxidized in the cytosol where it can cause oxidative stress so packaging into vesicles serves two purposes: neurotransmission and neuroprotection. Furthermore, the deleterious effects of exogenous toxicants on dopamine neurons, such as MPTP, can be attenuated by VMAT2 activity. The active metabolite of MPTP can be kept within vesicles and prevented from disrupting mitochondrial function thereby sparing the dopamine neuron. The highly addictive drug methamphetamine is also neurotoxic to dopamine neurons by using dopamine itself to destroy the axon terminals. Methamphetamine interferes with vesicular sequestration and increases the production of dopamine, escalating the amount in the cytosol and leading to oxidative damage of terminal components. Vesicular transport seems to resist this process by sequestering much of the excess dopamine, which is illustrated by the enhanced methamphetamine neurotoxicity in VMAT2-deficient mice. It is increasingly evident that VMAT2 provides neuroprotection from both endogenous and exogenous toxicants and that while VMAT2 has been adapted by eukaryotes for synaptic transmission, it is derived from phylogenetically ancient proteins that originally evolved for the purpose of cellular protection.

Modifications to toxic CUG RNAs induce structural stability, rescue mis-splicing in a myotonic dystrophy cell model and reduce toxicity in a myotonic dystrophy zebrafish model

DOE PAGES

deLorimier, Elaine; Coonrod, Leslie A.; Copperman, Jeremy; ...

2014-10-10

In this study, CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase ( DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecularmore » dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.« less

Water quality, selected chemical characteristics, and toxicity of base flow and urban stormwater in the Pearson Creek and Wilsons Creek Basins, Greene County, Missouri, August 1999 to August 2000

USGS Publications Warehouse

Richards, Joseph M.; Johnson, Byron Thomas

2002-01-01

The chemistry and toxicity of base flow and urban stormwater were characterized to determine if urban stormwater was degrading the water quality of the Pearson Creek and Wilsons Creek Basins in and near the city of Springfield, Greene County, Missouri. Potentially toxic components of stormwater (nutrients, trace metals, and organic compounds) were identified to help resource managers identify and minimize the sources of toxicants. Nutrient loading to the James River from these two basins (especially the Wilsons Creek Basin) is of some concern because of the potential to degrade downstream water quality. Toxicity related to dissolved trace metal constituents in stormwater does not appear to be a great concern in these two basins. Increased heterotrophic activity, the result of large densities of fecal indicator bacteria introduced into the streams after storm events, could lead to associated dissolved oxygen stress of native biota. Analysis of stormwater samples detected a greater number of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) than were present in base-flow samples. The number and concentrations of pesticides detected in both the base-flow and stormwater samples were similar.Genotoxicity tests were performed to determine the bioavilability of chemical contaminants and determine the potential harmful effects on aquatic biota of Pearson Creek and Wilsons Creek. Genotoxicity was determined from dialysates from both long-term (approximately 30 days) and storm-event (3 to 5 days) semipermeable membrane device (SPMD) samples that were collected in each basin. Toxicity tests of SPMD samples indicated evidence of genotoxins in all SPMD samples. Hepatic activity assessment of one long-term SPMD sample indicated evidence of contaminant uptake in fish. Chemical analyses of the SPMD samples found that relatively few pesticides and pesticide metabolites had been sequestered in the lipid material of the SPMD; however, numerous PAHs and VOCs were detected in both the long-term and the storm-event exposures. It is suspected, based on the compounds detected in the SPMDs and the water samples, that the observed genotoxicity is largely the result of PAHs and VOCs that were probably derived from petroleum inputs or combustion sources. Therefore the water quality and thus the aquatic environments in the Pearson Creek and Wilsons Creek Basins are being degraded by urban derived contaminants.

Genetic and Biochemical Analysis of High Iron Toxicity in Yeast

PubMed Central

Lin, Huilan; Li, Liangtao; Jia, Xuan; Ward, Diane McVey; Kaplan, Jerry

2011-01-01

Iron storage in yeast requires the activity of the vacuolar iron transporter Ccc1. Yeast with an intact CCC1 are resistant to iron toxicity, but deletion of CCC1 renders yeast susceptible to iron toxicity. We used genetic and biochemical analysis to identify suppressors of high iron toxicity in Δccc1 cells to probe the mechanism of high iron toxicity. All genes identified as suppressors of high iron toxicity in aerobically grown Δccc1 cells encode organelle iron transporters including mitochondrial iron transporters MRS3, MRS4, and RIM2. Overexpression of MRS3 suppressed high iron toxicity by decreasing cytosolic iron through mitochondrial iron accumulation. Under anaerobic conditions, Δccc1 cells were still sensitive to high iron toxicity, but overexpression of MRS3 did not suppress iron toxicity and did not result in mitochondrial iron accumulation. We conclude that Mrs3/Mrs4 can sequester iron within mitochondria under aerobic conditions but not anaerobic conditions. We show that iron toxicity in Δccc1 cells occurred under both aerobic and anaerobic conditions. Microarray analysis showed no evidence of oxidative damage under anaerobic conditions, suggesting that iron toxicity may not be solely due to oxidative damage. Deletion of TSA1, which encodes a peroxiredoxin, exacerbated iron toxicity in Δccc1 cells under both aerobic and anaerobic conditions, suggesting a unique role for Tsa1 in iron toxicity. PMID:21115478

In vivo contaminant partitioning to silicone implants: Implications for use in biomonitoring and body burden.

PubMed

O'Connell, Steven G; Kerkvliet, Nancy I; Carozza, Susan; Rohlman, Diana; Pennington, Jamie; Anderson, Kim A

2015-12-01

Silicone polymers are used for a wide array of applications from passive samplers in environmental studies, to implants used in human augmentation and reconstruction. If silicone sequesters toxicants throughout implantation, it may represent a history of exposure and potentially reduce the body burden of toxicants influencing the risk of adverse health outcomes such as breast cancer. Objectives of this research included identifying a wide variety of toxicants in human silicone implants, and measuring the in vivo absorption of contaminants into silicone and surrounding tissue in an animal model. In the first study, eight human breast implants were analyzed for over 1400 organic contaminants including consumer products, chemicals in commerce, and pesticides. A total of 14 compounds including pesticides such as trans-nonachlor (1.2-5.9ng/g) and p,p'-DDE (1.2-34ng/g) were identified in human implants, 13 of which have not been previously reported in silicone prostheses. In the second project, female ICR mice were implanted with silicone and dosed with p,p'-DDE and PCB118 by intraperitoneal injection. After nine days, silicone and adipose samples were collected, and all implants in dosed mice had p,p'-DDE and PCB118 present. Distribution ratios from silicone and surrounding tissue in mice compare well with similar studies, and were used to predict adipose concentrations in human tissue. Similarities between predicted and measured chemical concentrations in mice and humans suggest that silicone may be a reliable surrogate measure of persistent toxicants. More research is needed to identify the potential of silicone implants to refine the predictive quality of chemicals found in silicone implants. Copyright © 2015 Elsevier Ltd. All rights reserved.

Method for treating liquid wastes

DOEpatents

Katti, K.V.; Volkert, W.A.; Singh, P.; Ketring, A.R.

1995-12-26

The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering {sup 99}Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of {sup 99}TcO{sub 4}{sup {minus}} from aqueous solutions into organic solvents or mixed organic/polar media, extraction of {sup 99}Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester {sup 99}Tc from those liquids. 6 figs.

Method for treating liquid wastes

DOEpatents

Katti, Kattesh V.; Volkert, Wynn A.; Singh, Prahlad; Ketring, Alan R.

1995-01-01

The method of treating liquid waste in a media is accomplished by exposing the media to phosphinimines and sequestering .sup.99 Tc from the media by the phosphinimine (PN) functionalities. The system for treating the liquid waste in the media includes extraction of .sup.99 TcO.sub.4.sup.- from aqueous solutions into organic solvents or mixed organic/polar media, extraction of .sup.99 Tc from solutions on a solid matrix by using a container containing PN functionalities on solid matrices including an inlet and outlet for allowing flow of media through an immobilized phosphinimine ligand system contained within the container. Also, insoluble suspensions of phosphinimine functionalities on solid matrices in liquid solutions or present on supported liquid membranes (SLM) can be used to sequester .sup.99 Tc from those liquids.

DOE Office of Scientific and Technical Information (OSTI.GOV)

deLorimier, Elaine; Coonrod, Leslie A.; Copperman, Jeremy

In this study, CUG repeat expansions in the 3' UTR of dystrophia myotonica protein kinase ( DMPK) cause myotonic dystrophy type 1 (DM1). As RNA, these repeats elicit toxicity by sequestering splicing proteins, such as MBNL1, into protein–RNA aggregates. Structural studies demonstrate that CUG repeats can form A-form helices, suggesting that repeat secondary structure could be important in pathogenicity. To evaluate this hypothesis, we utilized structure-stabilizing RNA modifications pseudouridine (Ψ) and 2'-O-methylation to determine if stabilization of CUG helical conformations affected toxicity. CUG repeats modified with Ψ or 2'-O-methyl groups exhibited enhanced structural stability and reduced affinity for MBNL1. Molecularmore » dynamics and X-ray crystallography suggest a potential water-bridging mechanism for Ψ-mediated CUG repeat stabilization. Ψ modification of CUG repeats rescued mis-splicing in a DM1 cell model and prevented CUG repeat toxicity in zebrafish embryos. This study indicates that the structure of toxic RNAs has a significant role in controlling the onset of neuromuscular diseases.« less

Measuring the decomposition of organic carbon sequestered by salt marsh sediment

NASA Astrophysics Data System (ADS)

Light, T.; Mctigue, N.; Currin, C.

2016-12-01

As atmospheric carbon dioxide concentrations continue to rise, salt marshes are increasingly being recognized as a natural carbon sink, for large amounts of organic carbon are sequestered by salt marsh sediments. However, little is known regarding the fate of this "blue carbon" after salt marsh sediment is disturbed via erosion or lost due to sea level rise. This investigation explored novel methodologies for determining the lability of carbon sequestered by salt marsh sediment. Sediment cores were collected from a Spartina alterniflora-dominated marsh in Camp Lejeune, NC, and elemental analysis revealed that the upper 76 cm of sediment at the site contains a total carbon stock of 28.4 kg /m2. Sediment ranging from 251-545 years old, as determined through radiocarbon dating, was incubated under sub-aerial and aqueous conditions for 18 days and 25 days respectively. Carbon dioxide flux measurements revealed that shallower sediment organic matter decomposed more rapidly than deeper sediment in sub-aerial incubations, but decomposition was fairly slow in both treatments. No significant organic matter decomposition was observed in the aqueous incubations, as revealed by analyses of organic carbon remaining after the incubation period. The aqueous incubation included a treatment that had been "primed" with highly labile yeast extract, but no significant priming effect was observed over 25 days. While further investigation on the fate of this sediment carbon is needed, these preliminary findings indicate that salt marshes facilitate long-term carbon sequestration even after disturbances. This in turn supports the argument for mitigating anthropogenic carbon dioxide emissions through salt marsh restoration, and supports a policy of preserving and conserving coastal wetlands for this valuable ecosystem service.

The TRK1 potassium transporter is the critical effector for killing of Candida albicans by the cationic protein, Histatin 5.

PubMed

Baev, Didi; Rivetta, Alberto; Vylkova, Slavena; Sun, Jianing N; Zeng, Ge-Fei; Slayman, Clifford L; Edgerton, Mira

2004-12-31

The principal feature of killing of Candida albicans and other pathogenic fungi by the catonic protein Histatin 5 (Hst 5) is loss of cytoplasmic small molecules and ions, including ATP and K(+), which can be blocked by the anion channel inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. We constructed C. albicans strains expressing one, two, or three copies of the TRK1 gene in order to investigate possible roles of Trk1p (the organism's principal K(+) transporter) in the actions of Hst 5. All measured parameters (Hst 5 killing, Hst 5-stimulated ATP efflux, normal Trk1p-mediated K(+) ((86)Rb(+)) influx, and Trk1p-mediated chloride conductance) were similarly reduced (5-7-fold) by removal of a single copy of the TRK1 gene from this diploid organism and were fully restored by complementation of the missing allele. A TRK1 overexpression strain of C. albicans, constructed by integrating an additional TRK1 gene into wild-type cells, demonstrated cytoplasmic sequestration of Trk1 protein, along with somewhat diminished toxicity of Hst 5. These results could be produced either by depletion of intracellular free Hst 5 due to sequestered binding, or to cooperativity in Hst 5-protein interactions at the plasma membrane. Furthermore, Trk1p-mediated chloride conductance was blocked by 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid in all of the tested strains, strongly suggesting that the TRK1 protein provides the essential pathway for ATP loss and is the critical effector for Hst 5 toxicity in C. albicans.

Phytoremediation of Ionic and Methylmercury Pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richard Meagher

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species.

A mouse model study of toxicity and biodistribution of a replication defective adenovirus serotype 5 virus with its genome engineered to contain a decoy hyper binding site to sequester and suppress oncogenic HMGA1 as a new cancer treatment therapy.

PubMed

Hassan, Faizule; Lossie, Sarah L; Kasik, Ellen P; Channon, Audrey M; Ni, Shuisong; Kennedy, Michael A

2018-01-01

The HGMA1 architectural transcription factor is highly overexpressed in many human cancers. Because HMGA1 is a hub for regulation of many oncogenes, its overexpression in cancer plays a central role in cancer progression and therefore HMGA1 is gaining increasing attention as a target for development of therapeutic approaches to suppress either its expression or action in cancer cells. We have developed the strategy of introducing decoy hyper binding sites for HMGA1 into the nucleus of cancer cells with the goal of competetively sequestering overexpressed HMGA1 and thus suppressing its oncogenic action. Towards achieving this goal, we have introduced an HMGA1 decoy hyper binding site composed of six copies of a high affinity HMGA1 binding site into the genome of the replication defective adenovirus serotype 5 genome and shown that the engineered virus effectively reduces the viability of human pancreatic and cancer cells. Here we report the first pre-clinical measures of toxicity and biodistribution of the engineered virus in C57BL/6J Black 6 mice. The immune response to exposure of the engineered virus was determined by assaying the serum levels of key cytokines, IL-6 and TNF-α. Toxicity due to exposure to the virus was determined by measuring the serum levels of the liver enzymes aspartate aminotransferase and alanine aminotransferase. Biodistribution was measured following direct injection into the pancreas or liver by quantifying viral loads in the pancreas, liver, spleen and brain.

Soluble forms of polyQ-expanded huntingtin rather than large aggregates cause endoplasmic reticulum stress

NASA Astrophysics Data System (ADS)

Leitman, Julia; Ulrich Hartl, F.; Lederkremer, Gerardo Z.

2013-11-01

In Huntington’s disease, as in other neurodegenerative diseases, it was initially thought that insoluble protein aggregates are the toxic species. However, growing evidence implicates soluble oligomeric polyglutamine-expanded huntingtin in cytotoxicity. Here we show that pathogenic huntingtin inhibits endoplasmic reticulum (ER)-associated degradation and induces ER stress before its aggregation into visible inclusions. All three branches of the unfolded protein response are activated. ER stress can be compensated by overexpression of p97/VCP, suggesting its sequestration by pathogenic huntingtin as a main cause. Stress correlates with the presence of huntingtin oligomers and is independent of continual huntingtin synthesis. Stress levels, measured in striatal neurons, are stabilized but only slowly subside on huntingtin aggregation into inclusions. Our results can be explained by the constant conversion of huntingtin monomers to toxic oligomers; large aggregates sequester the former, precluding further conversion, whereas pre-existing toxic oligomers are only gradually depleted.

Microcin Amyloid Fibrils A Are Reservoir of Toxic Oligomeric Species

PubMed Central

Shahnawaz, Mohammad; Soto, Claudio

2012-01-01

Microcin E492 (Mcc), a low molecular weight bacteriocin produced by Klebsiella pneumoniae RYC492, has been shown to exist in two forms: soluble forms that are believed to be toxic to the bacterial cell by forming pores and non-toxic fibrillar forms that share similar biochemical and biophysical properties with amyloids associated with several human diseases. Here we report that fibrils polymerized in vitro from soluble forms sequester toxic species that can be released upon changing environmental conditions such as pH, ionic strength, and upon dilution. Our results indicate that basic pH (≥8.5), low NaCl concentrations (≤50 mm), and dilution (>10-fold) destabilize Mcc fibrils into more soluble species that are found to be toxic to the target cells. Additionally, we also found a similar conversion of non-toxic fibrils into highly toxic oligomers using Mcc aggregates produced in vivo. Moreover, the soluble protein released from fibrils is able to rapidly polymerize into amyloid fibrils under fibril-forming conditions and to efficiently seed aggregation of monomeric Mcc. Our findings indicate that fibrillar forms of Mcc constitute a reservoir of toxic oligomeric species that is released into the medium upon changing the environmental conditions. These findings may have substantial implications to understand the dynamic process of interconversion between toxic and non-toxic aggregated species implicated in protein misfolding diseases. PMID:22337880

Nanoparticle growth and surface chemistry changes in cell-conditioned culture medium.

PubMed

Kendall, Michaela; Hodges, Nikolas J; Whitwell, Harry; Tyrrell, Jess; Cangul, Hakan

2015-02-05

When biomolecules attach to engineered nanoparticle (ENP) surfaces, they confer the particles with a new biological identity. Physical format may also radically alter, changing ENP stability and agglomeration state within seconds. In order to measure which biomolecules are associated with early ENP growth, we studied ENPs in conditioned medium from A549 cell culture, using dynamic light scattering (DLS) and linear trap quadrupole electron transfer dissociation mass spectrometry. Two types of 100 nm polystyrene particles (one uncoated and one with an amine functionalized surface) were used to measure the influence of surface type. In identically prepared conditioned medium, agglomeration was visible in all samples after 1 h, but was variable, indicating inter-sample variability in secretion rates and extracellular medium conditions. In samples conditioned for 1 h or more, ENP agglomeration rates varied significantly. Agglomerate size measured by DLS was well correlated with surface sequestered peptide number for uncoated but not for amine coated polystyrene ENPs. Amine-coated ENPs grew much faster and into larger agglomerates associated with fewer sequestered peptides, but including significant sequestered lactose dehydrogenase. We conclude that interference with extracellular peptide balance and oxidoreductase activity via sequestration is worthy of further study, as increased oxidative stress via this new mechanism may be important for cell toxicity. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Na+/K+-ATPase resistance and cardenolide sequestration: basal adaptations to host plant toxins in the milkweed bugs (Hemiptera: Lygaeidae: Lygaeinae)

PubMed Central

Bramer, Christiane; Dobler, Susanne; Deckert, Jürgen; Stemmer, Michael; Petschenka, Georg

2015-01-01

Despite sequestration of toxins being a common coevolutionary response to plant defence in phytophagous insects, the macroevolution of the traits involved is largely unaddressed. Using a phylogenetic approach comprising species from four continents, we analysed the ability to sequester toxic cardenolides in the hemipteran subfamily Lygaeinae, which is widely associated with cardenolide-producing Apocynaceae. In addition, we analysed cardenolide resistance of their Na+/K+-ATPases, the molecular target of cardenolides. Our data indicate that cardenolide sequestration and cardenolide-resistant Na+/K+-ATPase are basal adaptations in the Lygaeinae. In two species that shifted to non-apocynaceous hosts, the ability to sequester was secondarily reduced, yet Na+/K+-ATPase resistance was maintained. We suggest that both traits evolved together and represent major coevolutionary adaptations responsible for the evolutionary success of lygaeine bugs. Moreover, specialization on cardenolides was not an evolutionary dead end, but enabled this insect lineage to host shift to cardenolide-producing plants from distantly related families. PMID:25808891

Can conservation tillage reduce N20 emissions on cropland transitioning to organic vegetable production?

USDA-ARS?s Scientific Manuscript database

Conservation soil management practices such as no-till (NT) and strip-till (ST) are effective ways to sequester carbon and increase soil organic matter in agricultural lands. However, the impact of these practices on other greenhouse gases (GHG) such as nitrous oxide (N2O) varies depending on soil ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The Voluntary Reporting Program, developed pursuant to Section 1605(b) of the Energy Policy Act of 1992, permits corporations, government agencies, households, and voluntary organizations to report on their emissions of greenhouse gases, and on actions taken that have reduced or avoided emissions or sequestered carbon, to the Energy Information Administration (EIA). This, the second annual report of the Voluntary Reporting Program, describes information provided by the participating organizations on their aggregate emissions and emissions reductions, as well as their emissions reduction or avoidance projects, through 1995. This information has been compiled into a database that includes reports from 142 organizationsmore » and descriptions of 967 projects that either reduced greenhouse gas emissions or sequestered carbon. Fifty-one reporters also provided estimates of emissions, and emissions reductions achieved, for their entire organizations. The projects described actions taken to reduce emissions of carbon dioxide from energy production and use; to reduce methane and nitrous oxide emissions from energy use, waste management, and agricultural processes; to reduce emissions of halocarbons, such as CFCs and their replacements; and to increase carbon sequestration.« less

Oil and oil dispersant do not cause synergistic toxicity to fish embryos.

PubMed

Adams, Julie; Sweezey, Michael; Hodson, Peter V

2014-01-01

Atlantic herring (Clupea harengus) embryos were exposed to water accommodated fractions (WAFs; oil dissolved in water) and chemically enhanced water accommodated fractions (CEWAFs; oil dispersed in water with Corexit 9500A) of Medium South American (MESA) crude oil. The CEWAF was approximately 100-fold more toxic than WAF based on nominal loadings of test solutions (% v/v). In contrast, the ratio of WAF and CEWAF toxicity expressed as measured oil concentrations approximated 1.0, indicating that the higher toxicity of CEWAFs was caused by an increase in exposure to hydrocarbons with chemical dispersion. In a second experiment, the chronic toxicity of Corexit 9500A and chemically dispersed heavy fuel oil 7102 (HFO 7102) to rainbow trout (Oncorhynchus mykiss) embryos was compared to chemically dispersed Nujol, a nontoxic mineral oil. Dispersant alone was toxic, but caused different signs of toxicity than HFO 7102. Nujol at a dispersant-to-oil ratio of 1:20 was nontoxic, suggesting that dispersant was sequestered by oil and not present at toxic concentrations. In contrast, the same nominal loadings of dispersed HFO 7102 caused concentration-dependent increases in toxicity. Both experiments suggest that chemically dispersed oil was more toxic to fish embryos than solutions created by mechanical mixing due to the increased exposure of fish to petroleum hydrocarbons and not to changes in hydrocarbon toxicity. The Nujol control discriminated between the toxicity of oil and chemical dispersant and would be a practical addition to programs of dispersant testing.

The chemistry of poisons in amphibian skin.

PubMed Central

Daly, J W

1995-01-01

Poisons are common in nature, where they often serve the organism in chemical defense. Such poisons either are produced de novo or are sequestered from dietary sources or symbiotic organisms. Among vertebrates, amphibians are notable for the wide range of noxious agents that are contained in granular skin glands. These compounds include amines, peptides, proteins, steroids, and both water-soluble and lipid-soluble alkaloids. With the exception of the alkaloids, most seem to be produced de novo by the amphibian. The skin of amphibians contains many structural classes of alkaloids previously unknown in nature. These include the batrachotoxins, which have recently been discovered to also occur in skin and feathers of a bird, the histrionicotoxins, the gephyrotoxins, the decahydroquinolines, the pumiliotoxins and homopumiliotoxins, epibatidine, and the samandarines. Some amphibian skin alkaloids are clearly sequestered from the diet, which consists mainly of small arthropods. These include pyrrolizidine and indolizidine alkaloids from ants, tricyclic coccinellines from beetles, and pyrrolizidine oximes, presumably from millipedes. The sources of other alkaloids in amphibian skin, including the batrachotoxins, the decahydroquinolines, the histrionicotoxins, the pumiliotoxins, and epibatidine, are unknown. While it is possible that these are produced de novo or by symbiotic microorganisms, it appears more likely that they are sequestered by the amphibians from as yet unknown dietary sources. PMID:7816854

Organic carbon stocks and sequestration rates of forest soils in Germany.

PubMed

Grüneberg, Erik; Ziche, Daniel; Wellbrock, Nicole

2014-08-01

The National Forest Soil Inventory (NFSI) provides the Greenhouse Gas Reporting in Germany with a quantitative assessment of organic carbon (C) stocks and changes in forest soils. Carbon stocks of the organic layer and the mineral topsoil (30 cm) were estimated on the basis of ca. 1.800 plots sampled from 1987 to 1992 and resampled from 2006 to 2008 on a nationwide grid of 8 × 8 km. Organic layer C stock estimates were attributed to surveyed forest stands and CORINE land cover data. Mineral soil C stock estimates were linked with the distribution of dominant soil types according to the Soil Map of Germany (1 : 1 000 000) and subsequently related to the forest area. It appears that the C pool of the organic layer was largely depending on tree species and parent material, whereas the C pool of the mineral soil varied among soil groups. We identified the organic layer C pool as stable although C was significantly sequestered under coniferous forest at lowland sites. The mineral soils, however, sequestered 0.41 Mg C ha(-1) yr(-1) . Carbon pool changes were supposed to depend on stand age and forest transformation as well as an enhanced biomass input. Carbon stock changes were clearly attributed to parent material and soil groups as sandy soils sequestered higher amounts of C, whereas clayey and calcareous soils showed small gains and in some cases even losses of soil C. We further showed that the largest part of the overall sample variance was not explained by fine-earth stock variances, rather by the C concentrations variance. The applied uncertainty analyses in this study link the variability of strata with measurement errors. In accordance to other studies for Central Europe, the results showed that the applied method enabled a reliable nationwide quantification of the soil C pool development for a certain period. © 2014 The Authors. Global Change Biology Published by John Wiley & Sons Ltd.

Organic carbon stocks and sequestration rates of forest soils in Germany

PubMed Central

Grüneberg, Erik; Ziche, Daniel; Wellbrock, Nicole

2014-01-01

The National Forest Soil Inventory (NFSI) provides the Greenhouse Gas Reporting in Germany with a quantitative assessment of organic carbon (C) stocks and changes in forest soils. Carbon stocks of the organic layer and the mineral topsoil (30 cm) were estimated on the basis of ca. 1.800 plots sampled from 1987 to 1992 and resampled from 2006 to 2008 on a nationwide grid of 8 × 8 km. Organic layer C stock estimates were attributed to surveyed forest stands and CORINE land cover data. Mineral soil C stock estimates were linked with the distribution of dominant soil types according to the Soil Map of Germany (1 : 1 000 000) and subsequently related to the forest area. It appears that the C pool of the organic layer was largely depending on tree species and parent material, whereas the C pool of the mineral soil varied among soil groups. We identified the organic layer C pool as stable although C was significantly sequestered under coniferous forest at lowland sites. The mineral soils, however, sequestered 0.41 Mg C ha−1 yr−1. Carbon pool changes were supposed to depend on stand age and forest transformation as well as an enhanced biomass input. Carbon stock changes were clearly attributed to parent material and soil groups as sandy soils sequestered higher amounts of C, whereas clayey and calcareous soils showed small gains and in some cases even losses of soil C. We further showed that the largest part of the overall sample variance was not explained by fine-earth stock variances, rather by the C concentrations variance. The applied uncertainty analyses in this study link the variability of strata with measurement errors. In accordance to other studies for Central Europe, the results showed that the applied method enabled a reliable nationwide quantification of the soil C pool development for a certain period. PMID:24616061

Directed Selection of Biochars for Amending Metal ...

EPA Pesticide Factsheets

Approximately 500,000 abandoned mines across the U.S. pose a considerable, pervasive risk to human health and the environment. World-wide the problem is even larger. Lime, organic matter, biosolids and other amendments have been used to decrease metal bioavailability in contaminated mine wastes and to promote the development of a mine waste stabilizing plant cover. The demonstrated properties of biochar make it a viable candidate as an amendment for remediating metal contaminated mine soils. In addition to sequestering potentially toxic metals, biochar can also be a source of plant nutrients, used to adjust soil pH, improve soil water holding characteristics, and increase soil carbon content. However, methods are needed for matching biochar beneficial properties with mine waste toxicities and soil health deficiencies. In this presentation we will report on a study in which we used mine soil from an abandoned Cu and Zn mine to develop a three-step procedure for identifying biochars that are most effective at reducing heavy metal bioavailability. Step 1: a slightly acidic extract of the mine spoil soil was produced, representing the potentially available metals, and used to identify metal removal properties of a library of 38 different biochars (e.g., made from a variety of feedstocks and pyrolysis or gasification conditions). Step 2: evaluation of how well these biochars retained (i.e., did not desorb) previously sorbed metals. Step 3: laboratory evalua

Addition of organic amendments contributes to C sequestration in trace element contaminated soils.

NASA Astrophysics Data System (ADS)

del Mar Montiel Rozas, María; Panettier, Marco; Madejón Rodríguez, Paula; Madejón Rodríguez, Engracia

2015-04-01

Nowadays, the study of global C cycle and the different natural sinks of C have become especially important in a climate change context. Fluxes of C have been modified by anthropogenic activities and, presently, the global objective is the decrease of net CO2 emission. For this purpose, many studies are being conducted at local level for evaluate different C sequestration strategies. These techniques must be, in addition to safe in the long term, environmentally friendly. Restoration of contaminated and degraded areas is considered as a strategy for SOC sequestration. Our study has been carried out in the Guadiamar Green Corridor (Seville, Spain) affected by the Aznalcóllar mining accident. This accident occurred 16 years ago, due to the failure of the tailing dam which contained 4-5 million m3 of toxic tailings (slurry and acid water).The affected soils had a layer of toxic sludge containing heavy metals as As, Cd, Cu, Pb and Zn. Restoration techniques began to be applied just after the accident, including the removal of the toxic sludge and a variable layer of topsoil (10-30 cm) from the surface. In a second phase, in a specific area (experimental area) of the Green Corridor the addition of organic amendments (Biosolid compost (BC) and Leonardite (LE), a low grade coal rich in humic acids) was carried out to increase pH, organic matter and fertility in a soil which lost its richest layer during the clean-up operation. In our experimental area, half of the plots (A) received amendments for four years (2002, 2003, 2006 and 2007) whereas the other half (B) received amendments only for two years (2002-2003). To compare, plots without amendments were also established. Net balance of C was carried out using values of Water Soluble Carbon (WSC) and Total Organic Carbon (TOC) for three years (2012, 2013 and 2015). To eliminate artificial changes carried out in the plots, amendment addition and withdrawal of biomass were taken into account to calculate balance of kg TOC ha ¯¹. Thus, results revealed the effect of amendments. Values of net balance show an increase in C sequestered in amended plots. The retention of carbon in soluble and total forms was reflected in the increase in time. According to the results, application of leonardite (a more stabilized amendment) seems to entail a greater retention of carbon in soil than in the case of biosolid compost. Restoration strategies have multiple benefits for the ecosystem. In our case, the use of organic amendments decreased trace element toxicity, improved soil structure and microbial communities, and contribute to retain C in terrestrial ecosystems.

Stabilization and destabilization of soil organic matter--a new focus

Treesearch

Phillip Sollins; Chris Swanston; Marc Kramer

2007-01-01

Interest in soil organic matter (SOM) is ramping up as concern mounts about steadily increasing levels of atmospheric CO2. There are two reasons for this. First, there is hope that improvements in crop, forest, and soil management may allow significant amounts of CO2 to be removed from the atmosphere and sequestered in soil...

Hydrophobic organochlorine compounds sequestered in submersed aquatic macrophytes (Hydrilla verticillata (L.F.) Royle) from the tidal Potomac River (USA).

PubMed

Hopple, J A; Foster, G D

1996-01-01

The potential for hydrophobic organochlorine contaminants to be sequestered in submersed aquatic vegetation was evaluated by determining the concentrations of cis- and trans-chlordane, dieldrin, and polychlorinated biphenyls (PCBs) in feral aquatic macrophytes (Hydrilla verticillata (L.f.) Royle) collected from the tidal Potomac River. Similarities in mean dry-weight concentrations of the identified organochlorine compounds in H. verticillata and surrounding alluvial sediments indicated that the extent of sequestration in H. verticillata was of the same magnitude as sorption of these compounds to river sediments, but some qualitative differences in PCB congener profiles existed. The results imply that to some degree H. verticillata can influence downstream fluxes of organic contaminants in fluvial transport in the Potomac River, and, furthermore, identify this species as a viable candidate organism for hydrophobic organochlorine contaminant biomonitoring in the Chesapeake Bay estuary.

Hydrophobic organochlorine compounds sequestered in submersed aquatic macrophytes (Hydrilla yerticillata (L.f.) Royle) from the tidal Potomac River (USA)

USGS Publications Warehouse

Hopple, J.A.; Foster, G.D.

1996-01-01

The potential for hydrophobic organochlorine contaminants to be sequestered in submersed aquatic vegetation was evaluated by determining the concentrations of cis- and trans-chlordane, dieldrin, and polychlorinated biphenyls (PCBs) in feral aquatic macrophytes (Hydrilla verticillata (L.f.) Royle) collected from the tidal Potomac River. Similarities in mean dry-weight concentrations of the identified organochlorine compounds in H. verticillata and surrounding alluvial sediments indicated that the extent of sequestration in H. verticillata was of the same magnitude as sorption of these compounds to river sediments, but some qualitative differences in PCB congener profiles existed. The results imply that to some degree H. verticillata can influence downstream fluxes of organic contaminants in fluvial transport in the Potomac River, and, furthermore, identify this species as a viable candidate organism for hydrophobic organochlorine contaminant biomonitoring in the Chesapeake Bay estuary.

Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

NASA Astrophysics Data System (ADS)

Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

2012-12-01

Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic fractions of suspended sediments. Copper is distributed in all but the carbonate fraction of suspended sediments. Vanadium was bound primarily to the oxide and residual fractions with Si, which is probably found as opal-α. In contrast, biofilm sediments had the highest concentrations of Fe, Si, Cd, Al, Zn, Ag, and Ni. Trace metals were sequestered mainly in the organic fraction in decreasing concentrations of: Cu

Preclinical evaluations of norcantharidin-loaded intravenous lipid microspheres with low toxicity.

PubMed

Lin, Xia; Zhang, Bo; Zhang, Keru; Zhang, Yu; Wang, Juan; Qi, Na; Yang, Shenshen; He, Haibing; Tang, Xing

2012-12-01

The aim of this study was to perform a systematic preclinical evaluation of norcantharidin (NCTD)-loaded intravenous lipid microspheres (NLM). Pharmacokinetics, biodistribution, antitumor efficacy and drug safety assessment (including acute toxicity, subchronic toxicity, hemolysis testing, intravenous stimulation and injection anaphylaxis) of NLM were carried out in comparison with the commercial product disodium norcantharidate injection (NI). The pharmacokinetics of NLM in rats was similar to that of NI, and a non-linear correlation was observed between AUC and dose. A comparable antitumor efficacy of NLM and NI was observed in mice inoculated with A549, BEL7402 and BCAP-37 cell lines. It was worth noting that the NLM produced a lower drug concentration in heart compared with NI, and significantly reduced the cardiac and renal toxicity. The LD(50) of NLM was twice higher than that of NI. In NLM, over 80% of NCTD was loaded in the lipid phase or bound with phospholipids. Thus, NCTD was sequestered by direct contacting with body fluids and largely avoided distribution into tissues, consequently leading to significantly reduced cardiac and renal toxicity. These preclinical results suggested that NLM could be a useful potential carrier for parenteral administration of NCTD, while providing a superior safety profile.

Effects of Fe plaque and organic acids on metal uptake by wetland plants under drained and waterlogged conditions.

PubMed

Li, W C; Deng, H; Wong, M H

2017-12-01

This study aims to assess the role of Fe plaque in metal uptake and translocation by different wetland plants and examine the effects of organic acids on metal detoxification in wetland plants. It was found that although exposed to a similar level of metals in rhizosphere soil solution, metal uptake by shoots of Cypercus flabelliformis and Panicum paludosum was greatly reduced, consequently leading to a better growth under flooded than under drained conditions. This may be related to the enhanced Fe plaque in the former, but due to the decreased root permeability in the latter under anoxic conditions. The Fe plaque on root surface has potential to sequester metals and then reduce metal concentrations and translocation in shoot tissues. However, whether the Fe plaque acts as a barrier to metal uptake and translocation may also be dependent on the root anatomy. Although metal tolerance in wetland plants mainly depends upon their metal exclusion ability, the higher-than-toxic-level of metal concentrations in some species indicates that internal metal detoxification might also exist. It was suggested that malic or citric acid in shoots of P. paludosum and C. flabelliformis may account for their internal detoxification for Zn. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anaerobic digestion of post-hydrothermal liquefaction wastewater for improved energy efficiency of hydrothermal bioenergy processes.

PubMed

Zhou, Yan; Schideman, Lance; Zheng, Mingxia; Martin-Ryals, Ana; Li, Peng; Tommaso, Giovana; Zhang, Yuanhui

2015-01-01

Hydrothermal liquefaction (HTL) is a promising process for converting wet biomass and organic wastes into bio-crude oil. It also produces an aqueous product referred to as post-hydrothermal liquefaction wastewater (PHWW) containing up to 40% of the original feedstock carbon, which reduces the overall energy efficiency of the HTL process. This study investigated the feasibility of using anaerobic digestion (AD) to treat PHWW, with the aid of activated carbon. Results showed that successful AD occurred at relatively low concentrations of PHWW (≤ 6.7%), producing a biogas yield of 0.5 ml/mg CODremoved, and ∼53% energy recovery efficiency. Higher concentrations of PHWW (≥13.3%) had an inhibitory effect on the AD process, as indicated by delayed, slower, or no biogas production. Activated carbon was shown to effectively mitigate this inhibitory effect by enhancing biogas production and allowing digestion to proceed at higher PHWW concentrations (up to 33.3%), likely due to sequestering toxic organic compounds. The addition of activated carbon also increased the net energy recovery efficiency of AD with a relatively high concentration of PHWW (33.3%), taking into account the energy for producing activated carbon. These results suggest that AD is a feasible approach to treat PHWW, and to improve the energy efficiency of the HTL processes.

Sulfur Mediated Alleviation of Mn Toxicity in Polish Wheat Relates to Regulating Mn Allocation and Improving Antioxidant System

PubMed Central

Sheng, Huajin; Zeng, Jian; Liu, Yang; Wang, Xiaolu; Wang, Yi; Kang, Houyang; Fan, Xing; Sha, Lina; Zhang, Haiqin; Zhou, Yonghong

2016-01-01

Sulfur (S) is an essential macronutrient that has been proved to play an important role in regulating plant responses to various biotic and abiotic stresses. The present study was designed to investigate the effect of S status on polish wheat plant response to Mn toxicity. Results showed that Mn stress inhibited plant growth, disturbed photosynthesis and induced oxidative stress. In response to Mn stress, polish wheat plant activated several detoxification mechanisms to counteract Mn toxicity, including enhanced antioxidant defense system, increased Mn distribution in the cell wall and up-regulated genes involved in S assimilation. Moderate S application was found to alleviate Mn toxicity mainly by sequestering excess Mn into vacuoles, inhibiting Mn translocation from roots to shoots, stimulating activities of antioxidant enzymes and enhancing GSH production via up-regulating genes involved in S metabolism. However, application of high level S to Mn-stressed plants did not significantly alleviated Mn toxicity likely due to osmotic stress. In conclusion, moderate S application is beneficial to polish wheat plant against Mn toxicity, S exerts its effects via stimulating the antioxidant defense system and regulating the translocation and subcellular distribution of Mn, in which processes GSH plays an indispensable role. PMID:27695467

PHYTOTECHNOLOGIES IN THE UNITED STATES: GROWING SOLUTIONS TO ENVIRONMENTAL CHALLENGES

EPA Science Inventory

Phytotechnology may be defined as the use of plants to contain, sequester, remove, or degrade organic and inorganic contaminants in soils, sediments, surface water, and groundwater. Mechanisms employed by the plant community may include transpiration (phytovolatilization), plant...

Development of a generalist predator, Podisus maculiventris, on glucosinolate sequestering and nonsequestering prey

NASA Astrophysics Data System (ADS)

van Geem, Moniek; Harvey, Jeffrey A.; Gols, Rieta

2014-09-01

Insect herbivores exhibit various strategies to counter the toxic effects of plant chemical defenses. These strategies include the detoxification, excretion, and sequestration of plant secondary metabolites. The latter strategy is often considered to provide an additional benefit in that it provides herbivores with protection against natural enemies such as predators. Profiles of sequestered chemicals are influenced by the food plants from which these chemicals are derived. We compared the effects of sequestration and nonsequestration of plant secondary metabolites in two specialist herbivores on the development of a generalist predator, Podisus maculiventris. Profiles of glucosinolates, secondary metabolites characteristic for the Brassicaceae, are known to differ considerably both inter- and intraspecifically. Throughout their immature (=nymphal) development, the predator was fed on larval stages of either sequestering (turnip sawfly, Athalia rosae) or nonsequestering (small cabbage white butterfly, Pieris rapae) prey that in turn had been feeding on plants originating from three wild cabbage ( Brassica oleracea) populations that have previously been shown to differ in their glucosinolate profiles. We compared survival, development time, and adult body mass as parameters for bug performance. Our results show that sequestration of glucosinolates by A. rosae only marginally affected the development of P. maculiventris. The effects of plant population on predator performance were variable. We suggest that sequestration of glucosinolates by A. rosae functions not only as a defensive mechanism against some predators, but may also be an alternative way of harmlessly dealing with plant allelochemicals.

NMR and mass spectrometry of phosphorus in wetlands

USGS Publications Warehouse

El-Rifai, H.; Heerboth, M.; Gedris, T.E.; Newman, S.; Orem, W.; Cooper, W.T.

2008-01-01

There is at present little information on the long-term stability of phosphorus sequestered in wetlands. Phosphorus sequestered during high loading periods may be relatively unstable and easily remobilized following changes in nutrient status or hydrological regime, but the chemical forms of sequestered phosphorus that do remobilize are largely unknown at this time. A lack of suitable analytical techniques has contributed to this dearth of knowledge regarding the stability of soil organic phosphorus. We analysed phosphorus in soils from the 'head' of Rescue Strand tree island and an adjacent marsh in the Florida Everglades by 31P nuclear magnetic resonance (NMR) spectroscopy and high-resolution mass spectrometry. Tree islands are important areas of biodiversity within the Everglades and offer a unique opportunity to study phosphorus sequestration because they are exposed to large phosphorus loads and appear to be natural nutrient sinks. The 31P NMR profiling of extracts from surface and sediment samples in the tree island indicates that phosphorus input to Rescue Strand tree island soils is mostly in the form of inorganic ortho-phosphate and is either refractory when deposited or rapidly recycled by the native vegetation into a stable phosphorus pool largely resistant to re-utilization by plants or microbes. Mass spectrometry revealed the presence of inositol hexakisphosphate, a common organic monophosphate ester not previously observed in Everglades' soils. ?? 2008 The Authors.

Soil carbon and nitrogen content and stabilization in mid-rotation, intensively managed sweetgum and loblolly stands

Treesearch

Kurt H. Johnsen; Lisa J. Samuelson; Felipe G. Sanchez; Bob Eaton

2013-01-01

Intensive forestry has resulted in considerable increases in aboveground stand productivity including foliar and belowground biomass which are the primary sources of soil organic matter. Soil organic matter is important for the maintenance of soil physical, chemical and biological quality. Additionally, sequestering carbon (C) in soils may provide a means of mitigating...

Hormesis enables cells to handle accumulating toxic metabolites during increased energy flux.

PubMed

Zemva, Johanna; Fink, Christoph Andreas; Fleming, Thomas Henry; Schmidt, Leonard; Loft, Anne; Herzig, Stephan; Knieß, Robert André; Mayer, Matthias; Bukau, Bernd; Nawroth, Peter Paul; Tyedmers, Jens

2017-10-01

Energy production is inevitably linked to the generation of toxic metabolites, such as reactive oxygen and carbonyl species, known as major contributors to ageing and degenerative diseases. It remains unclear how cells can adapt to elevated energy flux accompanied by accumulating harmful by-products without taking any damage. Therefore, effects of a sudden rise in glucose concentrations were studied in yeast cells. This revealed a feedback mechanism initiated by the reactive dicarbonyl methylglyoxal, which is formed non-enzymatically during glycolysis. Low levels of methylglyoxal activate a multi-layered defence response against toxic metabolites composed of prevention, detoxification and damage remission. The latter is mediated by the protein quality control system and requires inducible Hsp70 and Btn2, the aggregase that sequesters misfolded proteins. This glycohormetic mechanism enables cells to pre-adapt to rising energy flux and directly links metabolic to proteotoxic stress. Further data suggest the existence of a similar response in endothelial cells. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants.

PubMed

Seltzer, Michaeld; Berry, Kristinh

2005-03-01

The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: Documenting the uptake of elemental toxicants

USGS Publications Warehouse

Seltzer, M.D.; Berry, K.H.

2005-01-01

The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.

Nuclear micro-probe analysis of Arabidopsis thaliana leaves

NASA Astrophysics Data System (ADS)

Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; López-Martín, M. C.; Gotor, C.; Romero, L. C.

2003-09-01

Phytoremediation is a cost-effective plant-based approach for remediation of soils and waters which takes advantage of the remarkable ability of some plants to concentrate elements and compounds from the environment and to metabolize various molecules in their tissues, such as toxic heavy metals and organic pollutants. Nowadays, phytoremediation technology is becoming of paramount importance when environmental decontamination is concerned, due to the emerging knowledge of its physiological and molecular mechanisms and the new biological and engineering strategies designed to optimize and improve it. In addition, the feasibility of using plants for environmental cleanup has been confirmed by many different trials around the world. Arabidopsis thaliana plants can be used for basic studies to improve the technology on phytoremediation. Making use of nuclear microscopy techniques, in this paper we study leaves of wild type and transgenic A. thaliana plants grown in a cadmium-rich environment under different conditions. Micro-PIXE, RBS and SEM analyses, performed on the scanning proton micro-probe at the CNA in Seville (Spain), prove that cadmium is preferentially sequestered in the central region of epidermal trichome and allow comparing the effects of genetic modifications.

Diethylentriaminepenta acetic acid glucose conjugates as a cell permeable iron chelator.

PubMed

Mosayebnia, Mona; Shafiee-Ardestani, Mehdi; Pasalar, Parvin; Mashayekhi, Mojgan; Amanlou, Massoud

2014-01-01

To find out whether DTPA-DG complex can enhance clearance of intracellular free iron. Diethylenetriaminepentaacetic acid-D-deoxy-glucosamine (DTPA-DG) was synthesized and examined for its activity as a cell-permeable iron chelator in human hepatocellular carcinoma (HEPG2) cell line exposed to high concentration of iron sulfate and compared with deferoxamine (DFO), a prototype iron chelator. The effect of DTPA-DG on cell viability was monitored using the 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide MTT assay as well. There was a significant increase of iron level after iron overload induction in HEPG2 cell culture. DTPA-DG presented a remarkable capacity to iron burden reducing with estimated 50% inhibitory concentration value of 65.77 nM. In fact, glycosyl moiety was gained access of DTPA to intracellular iron deposits through glucose transporter systems. DTPA-DG, more potent than DFO to sequester deposits of free iron with no profound toxic effect. The results suggest the potential of DTPA-DG in chelating iron and permitting its excretion from primary organ storage.

Controlled burn and immediate mobilization of potentially toxic elements in soil, from a legacy mine site in Central Victoria, Australia.

PubMed

Abraham, Joji; Dowling, Kim; Florentine, Singarayer

2018-03-01

Conducting controlled burns in fire prone areas is an efficient and economic method for forest management, and provides relief from the incidence of high severity wild fires and the consequent damage to human property and ecosystems. However, similar to wild fires, controlled burns also affect many of the physical and biogeochemical properties of the forest soil and may facilitate remobilization of potentially toxic elements (PTEs) sequestered in vegetation and soil organic matter. The objective of the current study is to investigate the mobilization of PTEs, in Central Victorian forest soils in Australia after a controlled burn. Surface soil samples were collected two days before and after the controlled burn to determine the concentration of PTEs and to examine the physicochemical properties. Results show that As, Cd, Mn, Ni and Zn concentrations increased 1.1, 1.6, 1.7, 1.1 and 1.9 times respectively in the post-burn environment, whereas the concentrations of Hg, Cr and Pb decreased to 0.7, 0.9 and 0.9 times respectively, highlighting considerable PTE mobility during and after a controlled burn. Whilst these results do not identify very strong correlations between physicochemical properties of soil and PTEs in the pre- and post-burn environments, PTEs themselves demonstrated very strong and significant correlations. The mobilization of As, Hg and other toxic elements raise potential health concerns as the number of controlled burns are projected to increase in response to climate change. Due to this increased level of PTE release and remobilization, the use of any kinds of controlled burn must be carefully considered before being used as a forest management strategy in mining-affected landscapes which include areas with high PTE concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

The phytochelatin transporters AtABCC1 and AtABCC2 mediate tolerance to cadmium and mercury.

PubMed

Park, Jiyoung; Song, Won-Yong; Ko, Donghwi; Eom, Yujin; Hansen, Thomas H; Schiller, Michaela; Lee, Tai Gyu; Martinoia, Enrico; Lee, Youngsook

2012-01-01

Heavy metals such as cadmium (Cd) and mercury (Hg) are toxic pollutants that are detrimental to living organisms. Plants employ a two-step mechanism to detoxify toxic ions. First, phytochelatins bind to the toxic ion, and then the metal-phytochelatin complex is sequestered in the vacuole. Two ABCC-type transporters, AtABCC1 and AtABCC2, that play a key role in arsenic detoxification, have recently been identified in Arabidopsis thaliana. However, it is unclear whether these transporters are also implicated in phytochelatin-dependent detoxification of other heavy metals such as Cd(II) and Hg(II). Here, we show that atabcc1 single or atabcc1 atabcc2 double knockout mutants exhibit a hypersensitive phenotype in the presence of Cd(II) and Hg(II). Microscopic analysis using a Cd-sensitive probe revealed that Cd is mostly located in the cytosol of protoplasts of the double mutant, whereas it occurs mainly in the vacuole of wild-type cells. This suggests that the two ABCC transporters are important for vacuolar sequestration of Cd. Heterologous expression of the transporters in Saccharomyces cerevisiae confirmed their role in heavy metal tolerance. Over-expression of AtABCC1 in Arabidopsis resulted in enhanced Cd(II) tolerance and accumulation. Together, these results demonstrate that AtABCC1 and AtABCC2 are important vacuolar transporters that confer tolerance to cadmium and mercury, in addition to their role in arsenic detoxification. These transporters provide useful tools for genetic engineering of plants with enhanced metal tolerance and accumulation, which are desirable characteristics for phytoremediation. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed.

PubMed

Bhattarai, Mukesh Dev; Secchi, Silvia; Schoof, Justin

2017-01-01

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO 2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO 2 eq ha -1 yr -1 . Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO 2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO 2 eq ha -1 yr -1 . Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed

NASA Astrophysics Data System (ADS)

Bhattarai, Mukesh Dev; Secchi, Silvia; Schoof, Justin

2017-01-01

Land-based carbon sequestration constitutes a major low cost and immediately viable option in climate change mitigation. Using downscaled data from eight atmosphere-ocean general circulation models for a simulation period between 2015 and 2099, we examine the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed and the impact of climate change on crop yields. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 192.1 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 2.26 MtCO2 eq ha-1 yr-1. Our results also indicate that switchgrass can sequester the equivalent of 310.7 MtCO2 eq of soil organic carbon per hectare with a sequestration rate of 3.65 MtCO2 eq ha-1 yr-1. Our findings suggest that, unlike for corn and soybean yields, climate change does not have a significant effect on switchgrass yields, possibly due to the carbon fertilization effect.

AGRONOMIC OPTIMIZATION FOR PHYTOREMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBONS

EPA Science Inventory

Phytoremediation is a low-cost method of using plants to degrade, volatilize or sequester organic and metal pollutants that has been used in efforts to remediate sites contaminated with polycyclic aromatic hydrocarbon (PAH) refinery wastes. Non-native plant species aggressivel...

Environmental and Environmental-Health Implications of the USGS SAFRR California Tsunami Scenario

NASA Astrophysics Data System (ADS)

Plumlee, G. S.; Morman, S. A.; San Juan, C. A.

2013-12-01

The California Tsunami Scenario models the impacts of a hypothetical yet plausible tsunami caused by an earthquake offshore from the Alaskan Peninsula. Here, we interpret plausible tsunami-related contamination, environmental impacts, potential for human exposures to contaminants and hazardous materials, and implications for remediation and recovery. Inundation-related damages to major ports, boat yards, and many marinas could release complex debris, crude oil, various fuel types, other petroleum products, some liquid bulk cargo and dry bulk cargo, and diverse other pollutants into nearby coastal marine environments and onshore in the inundation zone. Tsunami-induced erosion of contaminated harbor bottom sediments could re-expose previously sequestered metal and organic pollutants (e.g., organotin, DDT). Inundation-related damage to many older buildings could produce complex debris containing lead paint, asbestos, pesticides, and other legacy contaminants. Intermingled household debris and externally derived debris and sediments would be left in flooded buildings. Post tsunami, mold would likely develop in inundated houses, buildings, and debris piles. Tsunamigenic fires in spilled oil, debris, cargo, vehicles, vegetation, and residential, commercial, or industrial buildings and their contents would produce potentially toxic gases and smoke, airborne ash, and residual ash/debris containing caustic alkali solids, metal toxicants, asbestos, and various organic toxicants. Inundation of and damage to wastewater treatment plants in many coastal cities could release raw sewage containing fecal solids, pathogens, and waste chemicals, as well as chemicals used to treat wastewaters. Tsunami-related physical damages, debris, and contamination could have short- and longer-term impacts on the environment and the health of coastal marine and terrestrial ecosystems. Marine habitats in intertidal zones, marshes, sloughs, and lagoons could be damaged by erosion or sedimentation, and could receive an influx of debris, metal and organic contaminants, and sewage-related pathogens. Debris and re-exposed contaminated sediments would be a source of sea- or rain-water-leachable metal and organic contaminants that could pose chronic toxicity threats to ecosystems. If human populations are successfully evacuated prior to the tsunami arrival, there would be no or limited numbers of drownings, other casualties, or related injuries, wounds, and infections. Immediately after the tsunami, human populations away from the inundation zone could be transiently exposed to airborne gases, smoke and ash from tsunamigenic fires. Post-tsunami cleanup, if done with appropriate mitigation (e.g., dust control), personal protection, and disposal measures, would help reduce the potential for cleanup-worker and resident exposures to toxicants and pathogens in harbor waters, debris, soils, ponded waters, and buildings. Cleanup and disposal, particularly of hazardous materials, would pose substantial logistical challenges and economic costs. Development of State and local policies that foster rapid assessment of potential contamination, as well as rapid decision making for disposal options should hazardous debris or sediment be identified, would help enhance resilience.

Choose Your Weaponry: Selective Storage of a Single Toxic Compound, Latrunculin A, by Closely Related Nudibranch Molluscs

PubMed Central

Cheney, Karen L.; White, Andrew; Mudianta, I. Wayan; Winters, Anne E.; Quezada, Michelle; Capon, Robert J.; Mollo, Ernesto; Garson, Mary J.

2016-01-01

Natural products play an invaluable role as a starting point in the drug discovery process, and plants and animals use many interesting biologically active natural products as a chemical defense mechanism against predators. Among marine organisms, many nudibranch gastropods are known to derive defensive metabolites from the sponges they eat. Here we investigated the putative sequestration of the toxic compound latrunculin A—a 16-membered macrolide that prevents actin polymerization within cellular processes—which has been identified from sponge sources, by five closely related nudibranch molluscs of the genus Chromodoris. Only latrunculin A was present in the rim of the mantle of these species, where storage reservoirs containing secondary metabolites are located, whilst a variety of secondary metabolites were found in their viscera. The species studied thus selectively accumulate latrunculin A in the part of the mantle that is more exposed to potential predators. This study also demonstrates that latrunculin-containing sponges are not their sole food source. Latrunculin A was found to be several times more potent than other compounds present in these species of nudibranchs when tested by in vitro and in vivo toxicity assays. Anti-feedant assays also indicated that latrunculin A was unpalatable to rock pool shrimps, in a dose-dependent manner. These findings led us to propose that this group of nudibranchs has evolved means both to protect themselves from the toxicity of latrunculin A, and to accumulate this compound in the mantle rim for defensive purposes. The precise mechanism by which the nudibranchs sequester such a potent compound from sponges without disrupting their own key physiological processes is unclear, but this work paves the way for future studies in this direction. Finally, the possible occurrence of both visual and chemosensory Müllerian mimicry in the studied species is discussed. PMID:26788920

Toxin-Antitoxin Systems as Multilevel Interaction Systems

PubMed Central

Goeders, Nathalie; Van Melderen, Laurence

2014-01-01

Toxin-antitoxin (TA) systems are small genetic modules usually composed of a toxin and an antitoxin counteracting the activity of the toxic protein. These systems are widely spread in bacterial and archaeal genomes. TA systems have been assigned many functions, ranging from persistence to DNA stabilization or protection against mobile genetic elements. They are classified in five types, depending on the nature and mode of action of the antitoxin. In type I and III, antitoxins are RNAs that either inhibit the synthesis of the toxin or sequester it. In type II, IV and V, antitoxins are proteins that either sequester, counterbalance toxin activity or inhibit toxin synthesis. In addition to these interactions between the antitoxin and toxin components (RNA-RNA, protein-protein, RNA-protein), TA systems interact with a variety of cellular factors, e.g., toxins target essential cellular components, antitoxins are degraded by RNAses or ATP-dependent proteases. Hence, TA systems have the capacity to interact with each other at different levels. In this review, we will discuss the different interactions in which TA systems are involved and their implications in TA system functions and evolution. PMID:24434905

Transition Metals and Virulence in Bacteria

PubMed Central

Palmer, Lauren D.; Skaar, Eric P.

2016-01-01

Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. Presumably, in response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface. PMID:27617971

Transition Metals and Virulence in Bacteria.

PubMed

Palmer, Lauren D; Skaar, Eric P

2016-11-23

Transition metals are required trace elements for all forms of life. Due to their unique inorganic and redox properties, transition metals serve as cofactors for enzymes and other proteins. In bacterial pathogenesis, the vertebrate host represents a rich source of nutrient metals, and bacteria have evolved diverse metal acquisition strategies. Host metal homeostasis changes dramatically in response to bacterial infections, including production of metal sequestering proteins and the bombardment of bacteria with toxic levels of metals. In response, bacteria have evolved systems to subvert metal sequestration and toxicity. The coevolution of hosts and their bacterial pathogens in the battle for metals has uncovered emerging paradigms in social microbiology, rapid evolution, host specificity, and metal homeostasis across domains. This review focuses on recent advances and open questions in our understanding of the complex role of transition metals at the host-pathogen interface.

A poisonous surprise under the coat of the African crested rat

PubMed Central

Kingdon, Jonathan; Agwanda, Bernard; Kinnaird, Margaret; O'Brien, Timothy; Holland, Christopher; Gheysens, Thomas; Boulet-Audet, Maxime; Vollrath, Fritz

2012-01-01

Plant toxins are sequestered by many animals and the toxicity is frequently advertised by aposematic displays to deter potential predators. Such ‘unpalatability by appropriation’ is common in many invertebrate groups and also found in a few vertebrate groups. However, potentially lethal toxicity by acquisition has so far never been reported for a placental mammal. Here, we describe complex morphological structures and behaviours whereby the African crested rat, Lophiomys imhausi, acquires, dispenses and advertises deterrent toxin. Roots and bark of Acokanthera schimperi (Apocynaceae) trees are gnawed, masticated and slavered onto highly specialized hairs that wick up the compound, to be delivered whenever the animal is bitten or mouthed by a predator. The poison is a cardenolide, closely resembling ouabain, one of the active components in a traditional African arrow poison long celebrated for its power to kill elephants. PMID:21813554

What does it take to detect a change in soil carbon stock? A regional comparison of minimum detectable difference and experiment duration in the North-Central United States

USDA-ARS?s Scientific Manuscript database

Accurate estimation of soil organic carbon (SOC) is crucial to efforts to improve soil fertility and stabilize atmospheric CO2 concentrations by sequestering carbon (C) in soils. Soil organic C measurements are, however, often highly variable and management practices can take a long time to produce ...

Assessing the impact of changes in climate and CO2 on potential carbon sequestration in agricultural soils

NASA Astrophysics Data System (ADS)

Jain, Atul K.; West, Tristram O.; Yang, Xiaojuan; Post, Wilfred M.

2005-10-01

Changes in soil management can potentially increase the accumulation of soil organic carbon (SOC), thereby sequestering CO2 from the atmosphere. However, the amount of carbon sequestered in soils can be augmented or lessened due to changes in climate and atmospheric CO2 concentration. The purpose of this paper is to study the influence of climate and CO2 feedbacks on soil carbon sequestration using a terrestrial carbon cycle model. Model simulations consist of observed adoption rates of no-tillage practices on croplands in the U.S. and Canada between 1981-2000. Model results indicate potential sequestration rates between 0.4-0.6 MgC/ha/yr in the Midwestern U.S. with decreasing rates towards the western, dryer regions of the U.S. It is estimated here that changes in climate and CO2 between 1981-2000 could be responsible for an additional soil carbon sequestration of 42 Tg. This is 5% of the soil carbon estimated to be potentially sequestered as the result of conversion to no-tillage in the U.S. and Canada.

Biodegradation of organic sulfur compounds in crude oils from Oman

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koopmans, M.P.; Sinninghe Damste, J.S.; Leeuw, J.W. de

1996-10-01

Five closely related crude oils from Oman, showing various degrees of biodegradation ranging from non-biodegraded to severely biodegraded, were quantitatively investigated for free and sulfur-bound hydrocarbons. Hydrocarbons sequestered in the alkylsulfide fraction and the polar fraction were analysed after Raney Ni desulfurisation and subsequent hydrogenation. With increasing degree of biodegradation, pristane (Pr), phytane (Ph) and a series of mid-chain methyl alkanes are enriched relative to the n-alkanes, as evidenced by increased Pr/n-C{sub 17} and Ph/n-C{sub 18} ratios. In the severely biodegraded oil no free n-alkanes, mid-chain alkanes or isoprenoid alkanes could be detected. Sterane and hopane distributions, however, remain unchangedmore » throughout the biodegradation series. Hydrocarbons sequestered in the alkylsulfide fraction (i.e. n-alkanes, mid-chain methyl alkanes, Pr and Ph) are biodegraded at lower rates than the corresponding hydrocarbons in the saturated hydrocarbon fraction. Similar hydrocarbons sequestered in the polar fraction are biodegraded at even lower rates. These results suggest that hydrocarbons bound by a higher amount of sulfur links are biodegraded at a lower rate.« less

Phytoremediation: Using green plants to clean up contaminated soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.

1996-05-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds ({open_quotes}organics{close_quotes}), and radioactive compounds in soil or water. Current research at Argonne National Laboratory includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. Amore » greenhouse experiment on zinc uptake in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data from Applied Natural Sciences, Inc. (our CRADA partner), indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known {open_quotes}hyperaccumulator{close_quotes} species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

Development of a simulated earthworm gut for determining bioaccessible arsenic, copper, and zinc from soil.

PubMed

Ma, Wai K; Smith, Ben A; Stephenson, Gladys L; Siciliano, Steven D

2009-07-01

Soil physicochemical characteristics and contamination levels alter the bioavailability of metals to terrestrial invertebrates. Current laboratory-derived benchmark concentrations used to estimate risk do not take into account site-specific conditions, such as contaminant sequestration, and site-specific risk assessment requires a battery of time-consuming and costly toxicity tests. The development of an in vitro simulator for earthworm bioaccessibility would significantly shorten analytical time and enable site managers to focus on areas of greatest concern. The simulated earthworm gut (SEG) was developed to measure the bioaccessibility of metals in soil to earthworms by mimicking the gastrointestinal fluid composition of earthworms. Three formulations of the SEG (enzymes, microbial culture, enzymes and microbial culture) were developed and used to digest field soils from a former industrial site with varying physicochemical characteristics and contamination levels. Formulations containing enzymes released between two to 10 times more arsenic, copper, and zinc from contaminated soils compared with control and 0.01 M CaCl2 extractions. Metal concentrations in extracts from SEG formulation with microbial culture alone were not different from values for chemical extractions. The mechanism for greater bioaccessible metal concentrations from enzyme-treated soils is uncertain, but it is postulated that enzymatic digestion of soil organic matter might release sequestered metal. The relevance of these SEG results will need validation through further comparison and correlation with bioaccumulation tests, alternative chemical extraction tests, and a battery of chronic toxicity tests with invertebrates and plants.

Trehalose 6,6′-Dimycolate and Lipid in the Pathogenesis of Caseating Granulomas of Tuberculosis in Mice

PubMed Central

Hunter, Robert L.; Olsen, Margaret; Jagannath, Chinnaswamy; Actor, Jeffrey K.

2006-01-01

Trehalose 6,6′-dimycolate (TDM) is the most abundant, most granulomagenic, and most toxic lipid extractable from the surface of virulent Mycobacterium tuberculosis (MTB). We further examined its toxicity, which requires activation by oily surfaces. Injections of MTB and/or TDM into sensitized mice induced caseating granulomas that centered on oil droplets. If large doses of MTB were injected in saline, caseating granulomas developed in adipose tissue, but MTB with surface TDM removed induced only acute inflammation that did not persist. Variations in protocols produced several variants of caseating granulomas, each with characteristics of human tuberculosis. In each instance, MTB were localized in fat cells or oil drops during initiation of caseating granulomas suggesting that necrosis was caused by activation of the toxicity of TDM toxicity. Evidence extending these findings to the lung was derived from the observation that in sensitized mice, as in humans, tuberculosis development stimulates accumulation of lipid selectively in alveoli. MTB preferentially associated with lipid droplets in developing necrotic foci in late-stage murine tuberculosis. This supports the hypothesis that pulmonary tuberculosis sequesters MTB in a protected environment that accumulates lipid until it is able to activate the toxicity of TDM and initiate necrosis that results in caseating granulomas. PMID:16565499

Modeling Dissolved Organic Carbon (DOC) Dynamics in Flooded Wetlands

EPA Science Inventory

Wetlands play an important role in the global carbon cycle and are recognized for their considerable potential to sequester carbon. Wetlands contain the largest component (18-30%) of the terrestrial carbon pool and are responsible for about a quarter of the global methane emissi...

Soil carbon sequestration is a climate stabilization wedge: comments on Sommer and Bossio (2014).

PubMed

Lassaletta, Luis; Aguilera, Eduardo

2015-04-15

Sommer and Bossio (2014) model the potential soil organic carbon (SOC) sequestration in agricultural soils (croplands and grasslands) during the next 87 years, concluding that this process cannot be considered as a climate stabilization wedge. We argue, however, that the amounts of SOC potentially sequestered in both scenarios (pessimistic and optimistic) fulfil the requirements for being considered as wedge because in both cases at least 25 GtC would be sequestered during the next 50 years. We consider that it is precisely in the near future, and meanwhile other solutions are developed, when this stabilization effort is most urgent even if after some decades the sequestration rate is significantly reduced. Indirect effects of SOC sequestration on mitigation could reinforce the potential of this solution. We conclude that the sequestration of organic carbon in agricultural soils as a climate change mitigation tool still deserves important attention for scientists, managers and policy makers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biochemical, Transcriptional, and Bioinformatic Analysis of Lipid Droplets from Seeds of Date Palm (Phoenix dactylifera L.) and Their Use as Potent Sequestration Agents against the Toxic Pollutant, 2,3,7,8-Tetrachlorinated Dibenzo-p-Dioxin.

PubMed

Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad; Rahman, Farzana; Blee, Elizabeth; Murphy, Denis J

2016-01-01

Contamination of aquatic environments with dioxins, the most toxic group of persistent organic pollutants (POPs), is a major ecological issue. Dioxins are highly lipophilic and bioaccumulate in fatty tissues of marine organisms used for seafood where they constitute a potential risk for human health. Lipid droplets (LDs) purified from date palm, Phoenix dactylifera, seeds were characterized and their capacity to extract dioxins from aquatic systems was assessed. The bioaffinity of date palm LDs toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins was determined. Fractioned LDs were spheroidal with mean diameters of 2.5 µm, enclosing an oil-rich core of 392.5 mg mL(-1). Isolated LDs did not aggregate and/or coalesce unless placed in acidic media and were strongly associated with three major groups of polypeptides of relative mass 32-37, 20-24, and 16-18 kDa. These masses correspond to the LD-associated proteins, oleosins, caleosins, and steroleosins, respectively. Efficient partitioning of TCDD into LDs occurred with a coefficient of log K LB/w,TCDD = 7.528 ± 0.024; it was optimal at neutral pH and was dependent on the presence of the oil-rich core, but was independent of the presence of LD-associated proteins. Bioinformatic analysis of the date palm genome revealed nine oleosin-like, five caleosin-like, and five steroleosin-like sequences, with predicted structures having putative lipid-binding domains that match their LD stabilizing roles and use as bio-based encapsulation systems. Transcriptomic analysis of date palm seedlings exposed to TCDD showed strong up-regulation of several caleosin and steroleosin genes, consistent with increased LD formation. The results suggest that the plant LDs could be used in ecological remediation strategies to remove POPs from aquatic environments. Recent reports suggest that several fungal and algal species also use LDs to sequester both external and internally derived hydrophobic toxins, which indicates that our approach could be used as a broader biomimetic strategy for toxin removal.

Biochemical, Transcriptional, and Bioinformatic Analysis of Lipid Droplets from Seeds of Date Palm (Phoenix dactylifera L.) and Their Use as Potent Sequestration Agents against the Toxic Pollutant, 2,3,7,8-Tetrachlorinated Dibenzo-p-Dioxin

PubMed Central

Hanano, Abdulsamie; Almousally, Ibrahem; Shaban, Mouhnad; Rahman, Farzana; Blee, Elizabeth; Murphy, Denis J.

2016-01-01

Contamination of aquatic environments with dioxins, the most toxic group of persistent organic pollutants (POPs), is a major ecological issue. Dioxins are highly lipophilic and bioaccumulate in fatty tissues of marine organisms used for seafood where they constitute a potential risk for human health. Lipid droplets (LDs) purified from date palm, Phoenix dactylifera, seeds were characterized and their capacity to extract dioxins from aquatic systems was assessed. The bioaffinity of date palm LDs toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener of dioxins was determined. Fractioned LDs were spheroidal with mean diameters of 2.5 µm, enclosing an oil-rich core of 392.5 mg mL-1. Isolated LDs did not aggregate and/or coalesce unless placed in acidic media and were strongly associated with three major groups of polypeptides of relative mass 32–37, 20–24, and 16–18 kDa. These masses correspond to the LD-associated proteins, oleosins, caleosins, and steroleosins, respectively. Efficient partitioning of TCDD into LDs occurred with a coefficient of log KLB/w,TCDD = 7.528 ± 0.024; it was optimal at neutral pH and was dependent on the presence of the oil-rich core, but was independent of the presence of LD-associated proteins. Bioinformatic analysis of the date palm genome revealed nine oleosin-like, five caleosin-like, and five steroleosin-like sequences, with predicted structures having putative lipid-binding domains that match their LD stabilizing roles and use as bio-based encapsulation systems. Transcriptomic analysis of date palm seedlings exposed to TCDD showed strong up-regulation of several caleosin and steroleosin genes, consistent with increased LD formation. The results suggest that the plant LDs could be used in ecological remediation strategies to remove POPs from aquatic environments. Recent reports suggest that several fungal and algal species also use LDs to sequester both external and internally derived hydrophobic toxins, which indicates that our approach could be used as a broader biomimetic strategy for toxin removal. PMID:27375673

Potential soil carbon sequestration in overgrazed grassland ecosystems

NASA Astrophysics Data System (ADS)

Conant, Richard T.; Paustian, Keith

2002-12-01

Excessive grazing pressure is detrimental to plant productivity and may lead to declines in soil organic matter. Soil organic matter is an important source of plant nutrients and can enhance soil aggregation, limit soil erosion, and can also increase cation exchange and water holding capacities, and is, therefore, a key regulator of grassland ecosystem processes. Changes in grassland management which reverse the process of declining productivity can potentially lead to increased soil C. Thus, rehabilitation of areas degraded by overgrazing can potentially sequester atmospheric C. We compiled data from the literature to evaluate the influence of grazing intensity on soil C. Based on data contained within these studies, we ascertained a positive linear relationship between potential C sequestration and mean annual precipitation which we extrapolated to estimate global C sequestration potential with rehabilitation of overgrazed grassland. The GLASOD and IGBP DISCover data sets were integrated to generate a map of overgrazed grassland area for each of four severity classes on each continent. Our regression model predicted losses of soil C with decreased grazing intensity in drier areas (precipitation less than 333 mm yr-1), but substantial sequestration in wetter areas. Most (93%) C sequestration potential occurred in areas with MAP less than 1800 mm. Universal rehabilitation of overgrazed grasslands can sequester approximately 45 Tg C yr-1, most of which can be achieved simply by cessation of overgrazing and implementation of moderate grazing intensity. Institutional level investments by governments may be required to sequester additional C.

Reactive Capping Mat Development and Evaluation for Sequestering Contaminants in Sediments

DTIC Science & Technology

2011-08-01

semi-permeable membrane devices (SPMDs) and solid phase micro-extraction (SPME) fibers . Peepers are expression samplers constructed of...in fish organs. The SPME fibers are coated with a liquid polymer that allows organic contaminants to establish equilibria between the fiber and the...between 10 and 20 cm of 300/200 µm polydimethylsiloxan (PMDS) fiber (Fiberguide) per replicate sample. Fibers were deployed at 10 cm lengths in a

Utilization of forest slash to sequester carbon in loblolly pine plantations in the lower coastal plain

Treesearch

F. Sanchez; E.A. Carter; W. Edwards

2002-01-01

Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

Spatial Associations and Chemical Composition of Organic Carbon Sequestered in Fe, Ca, and Organic Carbon Ternary Systems.

PubMed

Sowers, Tyler D; Adhikari, Dinesh; Wang, Jian; Yang, Yu; Sparks, Donald L

2018-05-25

Organo-mineral associations of organic carbon (OC) with iron (Fe) oxides play a major role in environmental OC sequestration, a process crucial to mitigating climate change. Calcium has been found to have high coassociation with OC in soils containing high Fe content, increase OC sorption extent to poorly crystalline Fe oxides, and has long been suspected to form bridging complexes with Fe and OC. Due to the growing realization that Ca may be an important component of C cycling, we launched a scanning transmission X-ray microscopy (STXM) investigation, paired with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, in order to spatially resolve Fe, Ca, and OC relationships and probe the effect of Ca on sorbed OC speciation. We performed STXM-NEXAFS analysis on 2-line ferrihydrite reacted with leaf litter-extractable dissolved OC and citric acid in the absence and presence of Ca. Organic carbon was found to highly associate with Ca ( R 2 = 0.91). Carboxylic acid moieties were dominantly sequestered; however, Ca facilitated the additional sequestration of aromatic and phenolic moieties. Also, C NEXAFS revealed polyvalent metal ion complexation. Our results provide evidence for the presence of Fe-Ca-OC ternary complexation, which has the potential to significantly impact how organo-mineral associations are modeled.

Formation of mercury sulfide from Hg(II)−thiolate complexes in natural organic matter

USGS Publications Warehouse

Alain Manceau,; Cyprien Lemouchi,; Mironel Enescu,; Anne-Claire Gaillot,; Martine Lanson,; Valerie Magnin,; Pieter Glatzel,; Poulin, Brett; Ryan, Joseph N.; Aiken, George R.; Isabelle Gautier-Lunea,; Kathryn L. Nagy,

2015-01-01

Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol-bound mercury with biogenic sulfide, but not in oxic environments. We present experimental evidence that mercury sulfide forms from thiol-bound mercury alone in aqueous dark systems in contact with air. The maximum amount of nanoparticulate mercury sulfide relative to thiol-bound mercury obtained by reacting dissolved mercury and soil organic matter matches that detected in the organic horizon of a contaminated soil situated downstream from Oak Ridge, TN, in the United States. The nearly identical ratios of the two forms of mercury in field and experimental systems suggest a common reaction mechanism for nucleating the mineral. We identified a chemical reaction mechanism that is thermodynamically favorable in which thiol-bound mercury polymerizes to mercury–sulfur clusters. The clusters form by elimination of sulfur from the thiol complexes via breaking of mercury–sulfur bonds as in an alkylation reaction. Addition of sulfide is not required. This nucleation mechanism provides one explanation for how mercury may be immobilized, and eventually sequestered, in oxygenated surface environments.

Wood smoke particle sequesters cell iron to impact a biological effect.

EPA Science Inventory

The biological effect of an inorganic particle (i.e., silica) can be associated with a disruption in cell iron homeostasis. Organic compounds included in particles originating from combustion processes can also complex sources of host cell iron to disrupt metal homeostasis. We te...

Voluntary Reporting of Greenhouse Gases

EIA Publications

2011-01-01

The Voluntary Reporting of Greenhouse Gases Program was suspended May 2011. It was a mechanism by which corporations, government agencies, individuals, voluntary organizations, etc., could report to the Energy Information Administration, any actions taken that have or are expected to reduce/avoid emissions of greenhouse gases or sequester carbon.

Bioremoval of heavy metals from industrial effluent by fixed-bed column of red macroalgae.

PubMed

Ibrahim, Wael M; Mutawie, Hawazin H

2013-02-01

Three different species of nonliving red algal biomass Laurancia obtusa, Geldiella acerosa and Hypnea sp. were used to build three types of fixed-bed column for the removal of toxic heavy metal ions such as Cu(2+), Zn(2+), Mn(2+) and Ni(2+) from industrial effluent. In general, the highest efficiency of metal ion bioremoval was recorded for algal column of L. obtusa followed by G. acerosa and the lowest one was recorded for Hypnea sp., with mean removal values of 94%, 85% and 71%, respectively. The obtained results showed that biological treatments of industrial effluents with these algal columns, using standard algal biotest, Pseudokirchneriella subcapitata, were capable of reducing effluent toxicities from 75% to 15%, respectively. Red algal column may be considered as an inexpensive and efficient alternative treatment for conventional removal technology, for sequestering heavy metal ions from industrial effluents.

Protein Misfolding Diseases.

PubMed

Hartl, F Ulrich

2017-06-20

The majority of protein molecules must fold into defined three-dimensional structures to acquire functional activity. However, protein chains can adopt a multitude of conformational states, and their biologically active conformation is often only marginally stable. Metastable proteins tend to populate misfolded species that are prone to forming toxic aggregates, including soluble oligomers and fibrillar amyloid deposits, which are linked with neurodegeneration in Alzheimer and Parkinson disease, and many other pathologies. To prevent or regulate protein aggregation, all cells contain an extensive protein homeostasis (or proteostasis) network comprising molecular chaperones and other factors. These defense systems tend to decline during aging, facilitating the manifestation of aggregate deposition diseases. This volume of the Annual Review of Biochemistry contains a set of three articles addressing our current understanding of the structures of pathological protein aggregates and their associated disease mechanisms. These articles also discuss recent insights into the strategies cells have evolved to neutralize toxic aggregates by sequestering them in specific cellular locations.

Protection against heavy metal toxicity by mucous and scales in fish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coello, W.F.; Khan, M.A.Q.

1995-12-31

Fingerlings of three freshwater fish species showed differences in susceptibility to lethality of 250 mg/L lead suspension or lead nitrate solution in water. Among these the large mouth bass Micropterus salmoides seemed to be more tolerant than green sunfish Lepomis cyanellus and goldfish Carassius auratus. Mucous from large mouth bass, when added to jars containing lead, lowered the toxicity of lead to sunfish and goldfish. Adding scales, especially if these were pretreated with an alkaline solution of cysteine and glycine, made all these species become tolerant to otherwise lethal concentrations of lead nitrate. The scales and mucous together buffered themore » acidity of lead nitrate and mercuric nitrate solution and sequestered hydrogen ions and lead and mercury from water and then settled to the bottom of jars. Scales of younger fingerling were more efficient than those of older ones.« less

Impact of agroforestry plantings for bioenergy production on soil organic carbon

USDA-ARS?s Scientific Manuscript database

Tree windbreaks are an attractive multiple-benefit land use through their ability to mitigate climate change by modifying the local microclimate to improve crop growth and by sequestering carbon in the soil and tree biomass. Recently, such agroforestry practices are also being considered for their b...

Arbuscular mycorrhizal fungi increase organic carbon decomposition under elevated carbon dioxide

USDA-ARS?s Scientific Manuscript database

A major goal of climate change research is to understand whether and how terrestrial ecosystems can sequester more carbon to mitigate rising atmospheric carbon dioxide (CO2) levels. The stimulation of arbuscular mycorrhizal fungi (AMF) by elevated atmospheric CO2 has been assumed to be a major mecha...

Effects of single-walled carbon nanotubes on the bioavailability of PCBs in field-contaminated sediments

EPA Science Inventory

Adsorption of hydrophobic organic contaminants (HOCs) to black carbon is a well studied phenomenon. One emerging class of engineered black carbon materials are single-walled carbon nanotubes (SWNT). Little research has investigated the potential of SWNT to adsorb and sequester HO...

Inactivation of E.coli 0157:H7 in cultivable soil by fast and slow pyrolysis-generated biochars

USDA-ARS?s Scientific Manuscript database

Biochar is a byproduct of incomplete combustion of organic matter, producing a fine, grainy, highly porous material. Benefits of biochar production include generation of bio-fuels, useful soil amendments for fertilizing crops, binding heavy metals, sequestering environmental biocarbon, and reducing...

Ocean urea fertilization for carbon credits poses high ecological risks.

PubMed

Glibert, Patricia M; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Anderson, Donald M; Beardall, John; Berg, G Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, Joann M; Cembella, Allan; Cochlan, William P; Collier, Jackie L; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J; Heil, Cynthia A; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A; Kana, Todd M; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O'Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Salomon, Paulo S; Solomon, Caroline; Stoecker, Diane K; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

2008-06-01

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed.

Ocean Urea Fertilization for Carbon Credits Poses High Ecological Risks

PubMed Central

Glibert, Patricia M.; Azanza, Rhodora; Burford, Michele; Furuya, Ken; Abal, Eva; Al-Azri, Adnan; Al-Yamani, Faiza; Andersen, Per; Beardall, John; Berg, G. Mine; Brand, Larry; Bronk, Deborah; Brookes, Justin; Burkholder, JoAnn M.; Cembella, Allan; Cochlan, William P.; Collier, Jackie; Collos, Yves; Diaz, Robert; Doblin, Martina; Drennen, Thomas; Dyhrman, Sonya; Fukuyo, Yasuwo; Furnas, Miles; Galloway, James; Granéli, Edna; Ha, Dao Viet; Hallegraeff, Gustaaf; Harrison, John; Harrison, Paul J.; Heil, Cynthia A.; Heimann, Kirsten; Howarth, Robert; Jauzein, Cécile; Kana, Austin A.; Kana, Todd M.; Kim, Hakgyoon; Kudela, Raphael; Legrand, Catherine; Mallin, Michael; Mulholland, Margaret; Murray, Shauna; O’Neil, Judith; Pitcher, Grant; Qi, Yuzao; Rabalais, Nancy; Raine, Robin; Seitzinger, Sybil; Solomon, Caroline; Stoecker, Diane K.; Usup, Gires; Wilson, Joanne; Yin, Kedong; Zhou, Mingjiang; Zhu, Mingyuan

2017-01-01

The proposed plan for enrichment of the Sulu Sea, Philippines, a region of rich marine biodiversity, with thousands of tonnes of urea in order to stimulate algal blooms and sequester carbon is flawed for multiple reasons. Urea is preferentially used as a nitrogen source by some cyanobacteria and dinoflagellates, many of which are neutrally or positively buoyant. Biological pumps to the deep sea are classically leaky, and the inefficient burial of new biomass makes the estimation of a net loss of carbon from the atmosphere questionable at best. The potential for growth of toxic dinoflagellates is also high, as many grow well on urea and some even increase their toxicity when grown on urea. Many toxic dinoflagellates form cysts which can settle to the sediment and germinate in subsequent years, forming new blooms even without further fertilization. If large-scale blooms do occur, it is likely that they will contribute to hypoxia in the bottom waters upon decomposition. Lastly, urea production requires fossil fuel usage, further limiting the potential for net carbon sequestration. The environmental and economic impacts are potentially great and need to be rigorously assessed. PMID:18439628

Characterization of zinc stress response in Cyanobacterium Synechococcus sp. IU 625.

PubMed

Newby, Robert; Lee, Lee H; Perez, Jose L; Tao, Xin; Chu, Tinchun

2017-05-01

The ability of cyanobacteria to survive many environmental stress factors is a testament to their resilience in nature. Of these environmental stress factors, overexposure to zinc is important to study since excessive zinc intake can be a severe hazard. Zinc toxicity in freshwater has been demonstrated to affects organisms such as invertebrates, algae and cyanobacteria. Cyanobacteria which possess increased resistance to zinc have been isolated. It is therefore important to elucidate the mechanism of survival and response to determine what factors allow their survival; as well as any remediation implications they may have. To characterize the effects of zinc in freshwater cyanobacteria, we investigated the response of Synechococcus sp. IU 625 (S. IU 625) over 29days to various concentrations (10, 25, and 50mg/L) of ZnCl 2 . S. IU 625 was shown to be tolerant up to 25mg/L ZnCl 2 exposure, with 10mg/L ZnCl 2 having no outward physiological change and 50mg/L ZnCl 2 proving lethal to the cells. To determine a potential mechanism Inductive Coupled Plasma-Mass Spectrometry (ICP-MS) and RNA-seq analysis were performed on zinc exposed cells. Analysis performed on days 4 and 7 indicated that response is dose-dependent, with 10mg/L ZnCl 2 exhibiting nearly all zinc extracellular, corresponding with upregulation of cation transport response. Whereas the 25mg/L ZnCl 2 exhibited half of total zinc sequestered by the cells, which corresponds with the upregulation of sequestering proteins such as metallothionein and the downregulation of genes involved with ATP synthesis and phycobilisome assembly. These analyses were combined with growth monitoring, microscopy, quantitative polymerase chain reaction (qPCR) and flow cytometry to present a full spectrum of mechanisms behind zinc response in S. IU 625. Copyright © 2017 Elsevier B.V. All rights reserved.

Soil Organic Carbon Sequestration by Tillage and Crop Rotation: A Global Data Analysis

DOE Data Explorer

West, Tristram O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Post, Wilfred M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2002-01-01

Changes in agricultural management can potentially increase the accumulation rate of soil organic carbon (SOC), thereby sequestering CO2 from the atmosphere. This study was conducted to quantify potential soil carbon (C) sequestration rates for different crops in response to decreasing tillage intensity or enhancing rotation complexity, and to estimate the duration of time over which sequestration may occur. Analyses of C sequestration rates were completed using a global database of 67 long-term agricultural experiments, consisting of 276 paired treatments. Results indicate, on average, that a change from conventional tillage (CT) to no-till (NT) can sequester 57 ± 14 g C m^–2 yr^–1, excluding wheat (Triticum aestivum L.)-fallow systems which may not result in SOC accumulation with a change from CT to NT. Enhancing rotation complexity can sequester an average 14 ± 11 g C m^–2 yr^–1, excluding a change from continuous corn (Zea mays L.) to corn-soybean (Glycine max L.) which may not result in a significant accumulation of SOC. Carbon sequestration rates, with a change from CT to NT, can be expected to peak in 5-10 yr with SOC reaching a new equilibrium in 15-20 yr. Following initiation of an enhancement in rotation complexity, SOC may reach a new equilibrium in approximately 40-60 yr. Carbon sequestration rates, estimated for a number of individual crops and crop rotations in this study, can be used in spatial modeling analyses to more accurately predict regional, national, and global C sequestration potentials.

Manganese toxicity upon overexposure

PubMed Central

Crossgrove, Janelle; Zheng, Wei

2014-01-01

Manganese (Mn) is a required element and a metabolic byproduct of the contrast agent mangafodipir trisodium (MnDPDP). The Mn released from MnDPDP is initially sequestered by the liver for first-pass elimination, which allows an enhanced contrast for diagnostic imaging. The administration of intravenous Mn impacts its homeostatic balance in the human body and can lead to toxicity. Human Mn deficiency has been reported in patients on parenteral nutrition and in micronutrient studies. Mn toxicity has been reported through occupational (e.g. welder) and dietary overexposure and is evidenced primarily in the central nervous system, although lung, cardiac, liver, reproductive and fetal toxicity have been noted. Mn neurotoxicity results from an accumulation of the metal in brain tissue and results in a progressive disorder of the extrapyramidal system which is similar to Parkinson's disease. In order for Mn to distribute from blood into brain tissue, it must cross either the blood–brain barrier (BBB) or the blood–cerebrospinal fluid barrier (BCB). Brain import, with no evidence of export, would lead to brain Mn accumulation and neurotoxicity. The mechanism for the neurodegenerative damage specific to select brain regions is not clearly understood. Disturbances in iron homeostasis and the valence state of Mn have been implicated as key factors in contributing to Mn toxicity. Chelation therapy with EDTA and supplementation with levodopa are the current treatment options, which are mildly and transiently efficacious. In conclusion, repeated administration of Mn, or compounds that readily release Mn, may increase the risk of Mn-induced toxicity. PMID:15617053

Water Utility Lime Sludge Reuse – An Environmental Sorbent for Power Utilities

EPA Science Inventory

Lime sludge can be used as an environmental sorbent to remove sulfur dioxide (SO2) and acid gases, by the ultra-fine CaCO3 particles, and to sequester mercury and other heavy metals, by the Natural Organic Matter and residual activated carbon. The laboratory experimental set up ...

Implications of observed and simulated soil carbon sequestration for management options in corn-based rotations

USDA-ARS?s Scientific Manuscript database

Managing cropping systems to sequester soil organic carbon (SOC) improves soil health and a system’s resiliency to impacts of changing climate. Our objectives were to 1) monitor SOC from a bio-energy cropping study in central Pennsylvania that included a corn-soybean-alfalfa rotation, switchgrass, a...

Implications of observed and simulated soil carbon sequestration for management options in corn-based rotations

USDA-ARS?s Scientific Manuscript database

Managing cropping systems to sequester soil organic carbon (SOC) improves soil health and a system’s resiliency to impacts of changing climate. Our objectives were to 1) monitor SOC from a bio-energy cropping study in central Pennsylvania that included a corn-soybean-alfalfa rotation, switchgrass, ...

Considerations involved with the use of semipermeable membrane devices for monitoring environmental contaminants

USGS Publications Warehouse

Petty, J.D.; Orazio, C.E.; Huckins, J.N.; Gale, R.W.; Lebo, J.A.; Meadows, J.C.; Echols, K.R.; Cranor, W.L.

2000-01-01

Semipermeable membrane devices (SPMDs) are used with increasing frequency, and throughout the world as samplers of organic contaminants. The devices can be used to detect a variety of lipophilic chemicals in water, sediment/soil, and air. SPMDs are designed to sample nonpolar, hydrophobic chemicals. The maximum concentration factor achievable for a particular chemical is proportional to its octanol–water partition coefficient. Techniques used for cleanup of SPMD extracts for targeted analytes and for general screening by full-scan mass spectrometry do not differ greatly from techniques used for extracts of other matrices. However, SPMD extracts contain potential interferences that are specific to the membrane–lipid matrix. Procedures have been developed or modified to alleviate these potential interferences. The SPMD approach has been demonstrated to be applicable to sequestering and analyzing a wide array of environmental contaminants including organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, polychlorinated dioxins and dibenzofurans, selected organophosphate pesticides and pyrethroid insecticides, and other nonpolar organic chemicals. We present herein an overview of effective procedural steps for analyzing exposed SPMDs for trace to ultra-trace levels of contaminants sequestered from environmental matrices.

United States National Sewage Sludge Repository at Arizona State University--a new resource and research tool for environmental scientists, engineers, and epidemiologists.

PubMed

Venkatesan, Arjun K; Done, Hansa Y; Halden, Rolf U

2015-02-01

Processed municipal sewage sludges (MSS) are an abundant, unwanted by-product of wastewater treatment, increasingly applied to agriculture and forestry for inexpensive disposal and soil conditioning. Due to their high organic carbon and lipid contents, MSS not only is rich in carbon and nutrients but also represents a "sink" for recalcitrant, hydrophobic, and potentially bioaccumulative compounds. Indeed, many organics sequestered and concentrated in MSS meet the US Environmental Protection Agency's definition of being persistent, bioaccumulative, and toxic (PBT). In a strategic effort, our research team at the Biodesign Institute has created the National Sewage Sludge Repository (NSSR), a large repository of digested MSSs from 164 wastewater treatment plants from across the USA, as part of the Human Health Observatory (H2O) at Arizona State University (ASU). The NSSR likely represents the largest archive of digested MSS specimens in the USA. The present study summarizes key findings gleaned thus far from analysis of NSSR samples. For example, we evaluated the content of toxicants in MSS and computed estimates of nationwide inventories of mass produced chemicals that become sequestrated in sludge and later are released into the environment during sludge disposal on land. Ongoing efforts document co-occurrence of a variety of PBT compounds in both MSS and human samples, while also identifying a large number of potentially harmful MSS constituents for which human exposure data are still lacking. Finally, we summarize future opportunities and invite collaborative use of the NSSR by the research community. The H2O at ASU represents a new resource and research tool for environmental scientists and the larger research community. As illustrated in this work, this repository can serve to (i) identify and prioritize emerging contaminants, (ii) provide spatial and temporal trends of contaminants, (iii) inform and evaluate the effectiveness of environmental policy-making and regulations, and (iv) approximate, ongoing exposures and body burdens of mass-produced chemicals in human society.

United States National Sewage Sludge Repository at Arizona State University – A New Resource and Research Tool for Environmental Scientists, Engineers, and Epidemiologists

PubMed Central

Venkatesan, Arjun K.; Done, Hansa Y.; Halden, Rolf U.

2014-01-01

Processed municipal sewage sludges (MSS) are an abundant, unwanted by-product of wastewater treatment, increasingly applied to agriculture and forestry for inexpensive disposal and soil conditioning. Due to their high organic-carbon and lipid contents, MSS not only is rich in carbon and nutrients but also represents a ‘sink’ for recalcitrant, hydrophobic and potentially bioaccumulative compounds. Indeed, many organics sequestered and concentrated in MSS meet the U.S. Environmental Protection Agency's definition of being persistent, bioaccumulative, and toxic (PBT). In a strategic effort, our research team at the Biodesign Institute has created the National Sewage Sludge Repository (NSSR), a large repository of digested MSSs from 164 wastewater treatment plants from across the USA, as part of the Human Health Observatory (H2O) at Arizona State University (ASU). The NSSR likely represents the largest archive of digested MSS specimens in the USA. The present study summarizes key findings gleaned thus far from analysis of NSSR samples. For example, we evaluated the content of toxicants in MSS and computed estimates of nationwide inventories of mass produced chemicals that become sequestrated in sludge and later are released into the environment during sludge disposal on land. Ongoing efforts document co-occurrence of a variety of PBT compounds in both MSS and human samples, while also identifying a large number of potentially harmful MSS constituents for which human exposure data are still lacking. Finally, we summarize new future opportunities and invite collaborative use the NSSR by the research community. The H2O at ASU represents a resource and research tool for environmental scientists and the larger research community. As illustrated in this work, this repository can serve to (i) identify and prioritize emerging contaminants; (ii) provide spatial and temporal trends of contaminants; (iii) inform and evaluate the effectiveness of environmental policy-making and regulations; and (iv) approximate, ongoing exposures and body burdens of mass-produced chemicals in human society. PMID:24824503

Development of a Rapid Assessment Method for Quantifying Carbon Sequestration on Reclaimed Coal Mine Sites

NASA Astrophysics Data System (ADS)

Maharaj, S.; Barton, C. D.; Karathanasis, A. D.

2005-12-01

Projected climate change resulting from elevated atmospheric carbon dioxide has given rise to various strategies designed to sequester carbon in various terrestrial ecosystems. Reclaimed coal mine soils present one such potential carbon sink where traditional reclamation objectives can complement carbon sequestration. However, quantifying new carbon (carbon that has been added to soil through recent biological processes) on reclaimed mine soils have proven to be difficult due to carbonates and coal particles present in the reclaimed coal mine spoils. Visible coal particles can be removed, but the microscopic coal dust particles remain. Additionally, with the advent of carbon trading on the stock market, rapid quantification of newly sequestered carbon has proven to be elusive. The focus of this project is to assess the potential of thermogravimetric analysis as a rapid, simple and direct method for differentiating and quantifying new carbon from old carbon (carbon of geologic origin) on reclaimed coal mine sites and provide a standard procedure for determining carbon sequestered in soil sinks. Thermogravimetry is a physico-chemical technique where the weight change is measured and recorded during the incremental heating of the soil sample over a temperature range of 25 to 1000 ° C. Grass litter and limestone were used as representative organic and inorganic carbon fractions, while coal was used to differentiate the old and new carbon within the organic fraction. Recoveries of mixtures at the 95 % confidence interval were found to be 94.49 ± 4.23 % (coal) , 93.67 ± 2.11 % (litter) , and 108.88 ± 2.88 % (limestone) respectively. Each of the above components appeared as distinct separate peaks on the thermograph, with litter appearing between 260 to 390 ° C, coal 425 to 480 ° C, and limestone 640 to 740 ° C. Overlapping peaks for the organic carbon represented by the grass litter may be indicative of cellulose and lignin fractions. Ongoing work in this area is being carried out to separate such peaks which may further enhance thermogravimetric analysis as an effective method to determine new carbon and to simultaneously monitor organic matter degradation.

Intensive management modifies soil CO2 efflux in 6-year-old Pinus taeda L. stands

Treesearch

Lisa J. Samuelson; Kurt Johnsen; Tom Stokes; Weinlang Lu

2004-01-01

Intensive forestry may reduce net CO2 emission into atmosphere by storing carbon in living biomass, dead organic matter and soil, and durable wood products. Because quantification of belowground carbon dynamics is important for reliable estimation of the carbon sequestered by intensively managed plantations, we examined soil CO2...

Chemical, physical and biological factors affecting wood decomposition in forest soils

Treesearch

Martin Jurgensen; Peter Laks; David Reed; Anne Collins; Deborah Page-Dumroese; Douglas Crawford

2004-01-01

Organic matter (OM) decomposition is an important variable in forest productivity and determining the potential of forest soils to sequester atmospheric CO2 (Grigal and Vance 2000; Kimble et al. 2003). Studies using OM from a particular location gives site-specific decomposition information, but differences in OM type and quality make it difficult to compare results...

A Recollection of mTOR Signaling in Learning and Memory

ERIC Educational Resources Information Center

Graber, Tyson E.; McCamphill, Patrick K.; Sossin, Wayne S.

2013-01-01

Mechanistic target of rapamcyin (mTOR) is a central player in cell growth throughout the organism. However, mTOR takes on an additional, more specialized role in the developed neuron, where it regulates the protein synthesis-dependent, plastic changes underlying learning and memory. mTOR is sequestered in two multiprotein complexes (mTORC1 and…

Boreal Forests Sequester Large Amounts of Mercury over Millennial Time Scales in the Absence of Wildfire.

PubMed

Giesler, Reiner; Clemmensen, Karina E; Wardle, David A; Klaminder, Jonatan; Bindler, Richard

2017-03-07

Alterations in fire activity due to climate change and fire suppression may have profound effects on the balance between storage and release of carbon (C) and associated volatile elements. Stored soil mercury (Hg) is known to volatilize due to wildfires and this could substantially affect the land-air exchange of Hg; conversely the absence of fires and human disturbance may increase the time period over which Hg is sequestered. Here we show for a wildfire chronosequence spanning over more than 5000 years in boreal forest in northern Sweden that belowground inventories of total Hg are strongly related to soil humus C accumulation (R 2 = 0.94, p < 0.001). Our data clearly show that northern boreal forest soils have a strong sink capacity for Hg, and indicate that the sequestered Hg is bound in soil organic matter pools accumulating over millennia. Our results also suggest that more than half of the Hg stock in the sites with the longest time since fire originates from deposition predating the onset of large-scale anthropogenic emissions. This study emphasizes the importance of boreal forest humus soils for Hg storage and reveals that this pool is likely to persist over millennial time scales in the prolonged absence of fire.

Compartmentalization of superoxide dismutase 1 (SOD1G93A) aggregates determines their toxicity

PubMed Central

Weisberg, Sarah J.; Lyakhovetsky, Roman; Werdiger, Ayelet-chen; Gitler, Aaron D.; Soen, Yoav; Kaganovich, Daniel

2012-01-01

Neurodegenerative diseases constitute a class of illnesses marked by pathological protein aggregation in the brains of affected individuals. Although these disorders are invariably characterized by the degeneration of highly specific subpopulations of neurons, protein aggregation occurs in all cells, which indicates that toxicity arises only in particular cell biological contexts. Aggregation-associated disorders are unified by a common cell biological feature: the deposition of the culprit proteins in inclusion bodies. The precise function of these inclusions remains unclear. The starting point for uncovering the origins of disease pathology must therefore be a thorough understanding of the general cell biological function of inclusions and their potential role in modulating the consequences of aggregation. Here, we show that in human cells certain aggregate inclusions are active compartments. We find that toxic aggregates localize to one of these compartments, the juxtanuclear quality control compartment (JUNQ), and interfere with its quality control function. The accumulation of SOD1G93A aggregates sequesters Hsp70, preventing the delivery of misfolded proteins to the proteasome. Preventing the accumulation of SOD1G93A in the JUNQ by enhancing its sequestration in an insoluble inclusion reduces the harmful effects of aggregation on cell viability. PMID:22967507

Redox and fungicidal properties of phthalocyanine metal complexes as related to active oxygen.

PubMed

Vol'pin, M E; Novodarova, G N; Krainova NYu; Lapikova, V P; Aver'yanov, A A

2000-10-01

Some chemical and fungicidal effects of 20 phthalocyanines of Co, Fe, Cu, and Al were studied. Under dark conditions, these complexes reduced nitroblue tetrazolium in the presence of KCN, accelerated the autoxidation of ascorbate or hydroquinone and decomposed hydrogen peroxide. In the later reaction, hydroxyl radical was generated as evidenced with the deoxyribose assay. The inhibition by superoxide dismutase and catalase of catalyzed autoxidation of ascorbate suggests the participation of superoxide anion-radical and hydrogen peroxide in the reaction. Most complexes were toxic to the fungus Magnaporthe grisea which causes blast disease of rice. The toxicity was enhanced by light being diminished by antioxidant reagents sequestering active oxygen species. Some complexes (including nontoxic ones), after 1-day contact with a leaf surface of the disease-susceptible rice cultivar, induced the fungitoxicity of leaf diffusate. This toxicity was also light-activated and sensitive to antioxidant reagents. Several complexes, when added to inocula, decreased 2-3 times the frequency of the compatible symptoms of the blast. It is suggested that in planta, the dark redox activity of phthalocyanines along with their photosensitization promote the generation of active oxygen, which damages the parasite and, therefore, favors disease resistance.

Feeding on toxic prey. The praying mantis (Mantodea) as predator of poisonous butterfly and moth (Lepidoptera) caterpillars.

PubMed

Mebs, Dietrich; Wunder, Cora; Pogoda, Werner; Toennes, Stefan W

2017-06-01

Caterpillars of the monarch butterfly, Danaus plexippus, feed on milkweed plants, Asclepias spp. (Apocynaceae), and sequester their toxic cardenolides aimed at deterring predators. Nevertheless, Chinese praying mantids, Tenodera sinensis, consume these caterpillars after removing the midgut ("gutting") including its plant content. In the present study, monarch caterpillars raised on A. curassavica, and those of the death's-head hawkmoth, Acherontia atropos, raised on Atropa belladonna containing atropine, were fed to mantids, Hierodula membranacea, which removed the gut of both species discarding about 59% of cardenolides and more than 90% of atropine, respectively. The ingestion of these compounds produced no apparent ill effects in the mantids and both were excreted with faeces. On the other hand, when mantids were fed with larvae of two moth species, Amata mogadorensis and Brahmaea certia, raised on non-poisonous host plants, the mantids showed the same gutting behaviour, thereby discarding indigestible plant material. As polar compounds, e.g. cardenolides and atropine, are not absorbed from the mantids midgut and do not pass the gut membrane, this enables the mantids to feed on toxic prey. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fermentation process for the production of organic acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hermann, Theron; Reinhardt, James; Yu, Xiaohui

This invention relates to improvements in the fermentation process used in the production of organic acids from biological feedstock using bacterial catalysts. The improvements in the fermentation process involve providing a fermentation medium comprising an appropriate form of inorganic carbon, an appropriate amount of aeration and a biocatalyst with an enhanced ability to uptake and assimilate the inorganic carbon into the organic acids. This invention also provides, as a part of an integrated fermentation facility, a novel process for producing a solid source of inorganic carbon by sequestering carbon released from the fermentation in an alkali solution.

Phytoremediation: using green plants to clean up contaminate soil, groundwater, and wastewater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Negri, M.C.; Hinchman, R.R.; Gatliff, E.G.

1996-07-01

Phytoremediation, an emerging cleanup technology for contaminated soils, groundwater, and wastewater that is both low-tech and low-cost, is defined as the engineered use of green plants (including grasses, forbs, and woody species) to remove, contain, or render harmless such environmental contaminants as heavy metals, trace elements, organic compounds and radioactive compounds in soil or water. Our research includes a successful field demonstration of a plant bioreactor for processing the salty wastewater from petroleum wells; the demonstration is currently under way at a natural gas well site in Oklahoma, in cooperation with Devon Energy Corporation. A greenhouse experiment on zinc uptakemore » in hybrid poplar (Populus sp.) was initiated in 1995. These experiments are being conducted to confirm and extend field data indicating high levels of zinc (4,200 ppm) in leaves of hybrid poplar growing as a cleanup system at a site with zinc contamination in the root zone of some of the trees. Analyses of soil water from experimental pots that had received several doses of zinc indicated that the zinc was totally sequestered by the plants in about 4 hours during a single pass through the root system. The data also showed concentrations of sequestered metal of >38,000 ppm Zn in the dry root tissue. These levels of sequestered zinc exceed the levels found in either roots or tops of many of the known ``hyperaccumulator`` species. Because the roots sequester most of the contaminant taken up in most plants, a major objective of this program is to determine the feasibility of root harvesting as a method to maximize the removal of contaminants from soils. Available techniques and equipment for harvesting plant roots, including young tree roots, are being evaluated and modified as necessary for use with phytoremediation plants.« less

What is soil organic matter worth?

PubMed

Sparling, G P; Wheeler, D; Vesely, E-T; Schipper, L A

2006-01-01

The conservation and restoration of soil organic matter are often advocated because of the generally beneficial effects on soil attributes for plant growth and crop production. More recently, organic matter has become important as a terrestrial sink and store for C and N. We have attempted to derive a monetary value of soil organic matter for crop production and storage functions in three contrasting New Zealand soil orders (Gley, Melanic, and Granular Soils). Soil chemical and physical characteristics of real-life examples of three pairs of matched soils with low organic matter contents (after long-term continuous cropping for vegetables or maize) or high organic matter content (continuous pasture) were used as input data for a pasture (grass-clover) production model. The differences in pasture dry matter yields (non-irrigated) were calculated for three climate scenarios (wet, dry, and average years) and the yields converted to an equivalent weight and financial value of milk solids. We also estimated the hypothetical value of the C and N sequestered during the recovery phase of the low organic matter content soils assuming trading with C and N credits. For all three soil orders, and for the three climate scenarios, pasture dry matter yields were decreased in the soils with lower organic matter contents. The extra organic matter in the high C soils was estimated to be worth NZ$27 to NZ$150 ha(-1) yr(-1) in terms of increased milk solids production. The decreased yields from the previously cropped soils were predicted to persist for 36 to 125 yr, but with declining effect as organic matter gradually recovered, giving an accumulated loss in pastoral production worth around NZ$518 to NZ$1239 ha(-1). This was 42 to 73 times lower than the hypothetical value of the organic matter as a sequestering agent for C and N, which varied between NZ$22,963 to NZ$90,849 depending on the soil, region, discount rates, and values used for carbon and nitrogen credits.

The Ability of Bacterial Cocaine Esterase to Hydrolyze Cocaine Metabolites and Their Simultaneous Quantification Using High-Performance Liquid Chromatography-Tandem Mass Spectrometry

PubMed Central

Brim, Remy L.; Noon, Kathleen R.; Collins, Gregory T.; Nichols, Joseph; Narasimhan, Diwahar; Sunahara, Roger K.

2011-01-01

Cocaine toxicity is a widespread problem in the United States, responsible for more than 500,000 emergency department visits a year. There is currently no U.S. Food and Drug Administration-approved pharmacotherapy to directly treat cocaine toxicity. To this end, we have developed a mutant bacterial cocaine esterase (DM-CocE), which has been previously shown to rapidly hydrolyze cocaine into inert metabolites, preventing and reversing toxicity with limited immunogenic potential. Herein we describe the ability of DM-CocE to hydrolyze the active cocaine metabolites norcocaine and cocaethylene and its inability to hydrolyze benzoylecgonine. DM-CocE hydrolyzes norcocaine and cocaethylene with 58 and 45% of its catalytic efficiency for cocaine in vitro as measured by a spectrophotometric assay. We have developed a mass spectrometry method to simultaneously detect cocaine, benzoylecgonine, norcocaine, and ecgonine methyl ester to quantify the effect of DM-CocE on normal cocaine metabolism in vivo. DM-CocE administered to rats 10 min after a convulsant dose of cocaine alters the normal metabolism of cocaine, rapidly decreasing circulating levels of cocaine and norcocaine while increasing ecgonine methyl ester formation. Benzoylecgonine was not hydrolyzed in vivo, but circulating concentrations were reduced, suggesting that DM-CocE may bind and sequester this metabolite. These findings suggest that DM-CocE may reduce cocaine toxicity by eliminating active and toxic metabolites along with the parent cocaine molecule. PMID:21885621

Physical Aspects of Photodynamic Corneal Collagen Crosslinking

NASA Astrophysics Data System (ADS)

Kornfield, Julia

2012-02-01

Healthy vision depends on the stability of the shape of the cornea, which provides most of the lens power of the optical system of the eye. Diseases in which the cornea progressively undergoes irregular deformation over time (e.g., keratoconus) can be treated clinically by inducing additional protein-protein crosslinks using a photosensitizing drug and a tailored dose of light. Unfortunately, the treatment moving through clinical trials is toxic to cells in and on the cornea. A path to a safer treatment is offered by the nanostructure of the corneal stroma---reminiscent of a HEX phase in block copolymers with 30nm diameter collagen cylinders spaced 60nm center-to-center in a hydrogel matrix of proteoglycans and water. We show that using a photosensitizing drug that sequesters itself in the collagen fibrils can minimize the toxicity of therapeutic protein-protein cross-linking. Photorheology and transport measurements are used to quantify the parameters of a simple physical model that is useful for optimizing clinical protocols.

Molecular basis for disruption of E-cadherin adhesion by botulinum neurotoxin A complex.

PubMed

Lee, Kwangkook; Zhong, Xiaofen; Gu, Shenyan; Kruel, Anna Magdalena; Dorner, Martin B; Perry, Kay; Rummel, Andreas; Dong, Min; Jin, Rongsheng

2014-06-20

How botulinum neurotoxins (BoNTs) cross the host intestinal epithelial barrier in foodborne botulism is poorly understood. Here, we present the crystal structure of a clostridial hemagglutinin (HA) complex of serotype BoNT/A bound to the cell adhesion protein E-cadherin at 2.4 angstroms. The HA complex recognizes E-cadherin with high specificity involving extensive intermolecular interactions and also binds to carbohydrates on the cell surface. Binding of the HA complex sequesters E-cadherin in the monomeric state, compromising the E-cadherin-mediated intercellular barrier and facilitating paracellular absorption of BoNT/A. We reconstituted the complete 14-subunit BoNT/A complex using recombinantly produced components and demonstrated that abolishing either E-cadherin- or carbohydrate-binding of the HA complex drastically reduces oral toxicity of BoNT/A complex in vivo. Together, these studies establish the molecular mechanism of how HAs contribute to the oral toxicity of BoNT/A. Copyright © 2014, American Association for the Advancement of Science.

Sequestration of arsenic in ombrotrophic peatlands

NASA Astrophysics Data System (ADS)

Rothwell, James; Hudson-Edwards, Karen; Taylor, Kevin; Polya, David; Evans, Martin; Allott, Tim

2014-05-01

Peatlands can be important stores of arsenic but we are lacking spectroscopic evidence of the sequestration pathways of this toxic metalloid in peatland environments. This study reports on the solid-phase speciation of anthropogenically-derived arsenic in atmospherically contaminated peat from the Peak District National Park (UK). Surface and sub-surface peat samples were analysed by synchrotron X-ray absorption spectroscopy on B18 beamline at Diamond Light Source (UK). The results suggest that there are contrasting arsenic sequestration mechanisms in the peat. The bulk arsenic speciation results, in combination with strong arsenic-iron correlations at the surface, suggest that iron (hydr)oxides are key phases for the immobilisation of arsenic at the peat surface. In contrast, the deeper peat samples are dominated by arsenic sulphides (arsenopyrite, realgar and orpiment). Given that these peats receive inputs solely from the atmosphere, the presence of these sulphide phases suggests an in-situ authigenic formation. Redox oscillations in the peat due to a fluctuating water table and an abundant store of legacy sulphur from historic acid rain inputs may favour the precipitation of arsenic sequestering sulphides in sub-surface horizons. Oxidation-induced loss of these arsenic sequestering sulphur species by water table drawdown has important implications for the mobility of arsenic and the quality of waters draining peatlands.

Differential contributions of Caenorhabditis elegans histone deacetylases to huntingtin polyglutamine toxicity.

PubMed

Bates, Emily A; Victor, Martin; Jones, Adriana K; Shi, Yang; Hart, Anne C

2006-03-08

Expansion of a polyglutamine tract in the huntingtin protein causes neuronal degeneration and death in Huntington's disease patients, but the molecular mechanisms underlying polyglutamine-mediated cell death remain unclear. Previous studies suggest that expanded polyglutamine tracts alter transcription by sequestering glutamine rich transcriptional regulatory proteins, thereby perturbing their function. We tested this hypothesis in Caenorhabditis elegans neurons expressing a human huntingtin fragment with an expanded polyglutamine tract (Htn-Q150). Loss of function alleles and RNA interference (RNAi) were used to examine contributions of C. elegans cAMP response element-binding protein (CREB), CREB binding protein (CBP), and histone deacetylases (HDACs) to polyglutamine-induced neurodegeneration. Deletion of CREB (crh-1) or loss of one copy of CBP (cbp-1) enhanced polyglutamine toxicity in C. elegans neurons. Loss of function alleles and RNAi were then used to systematically reduce function of each C. elegans HDAC. Generally, knockdown of individual C. elegans HDACs enhanced Htn-Q150 toxicity, but knockdown of C. elegans hda-3 suppressed toxicity. Neuronal expression of hda-3 restored Htn-Q150 toxicity and suggested that C. elegans HDAC3 (HDA-3) acts within neurons to promote degeneration in response to Htn-Q150. Genetic epistasis experiments suggested that HDA-3 and CRH-1 (C. elegans CREB homolog) directly oppose each other in regulating transcription of genes involved in polyglutamine toxicity. hda-3 loss of function failed to suppress increased neurodegeneration in hda-1/+;Htn-Q150 animals, indicating that HDA-1 and HDA-3 have different targets with opposing effects on polyglutamine toxicity. Our results suggest that polyglutamine expansions perturb transcription of CREB/CBP targets and that specific targeting of HDACs will be useful in reducing associated neurodegeneration.

NMR detects molecular interactions of graphene with aromatic and aliphatic hydrocarbons in water

NASA Astrophysics Data System (ADS)

Bichenkova, Elena V.; Raju, Arun P. A.; Burusco, Kepa K.; Kinloch, Ian A.; Novoselov, Kostya S.; Clarke, David J.

2018-03-01

Polyaromatic carbon is widely held to be strongly diamagnetic and hydrophobic, with textbook van der Waals and ‘π-stacked’ binding of hydrocarbons, which disrupt their self-assembled supramolecular structures. The NMR of organic molecules sequestered by polyaromatic carbon is expected to be dominated by shielding from the orbital diamagnetism of π electrons. We report the first evidence of very different polar and magnetic behavior in water, wherein graphene remained well-dispersed after extensive dialysis and behaved as a 1H-NMR-silent ghost. Magnetic effects dominated the NMR of organic structures which interacted with graphene, with changes in spin-spin coupling, vast increase in relaxation, line broadening and decrease in NMR peak heights when bound to graphene. However, the interactions were weak, reversible and did not disrupt organic self-assemblies reliant on hydrophobic ‘π-stacking’, even when substantially sequestered on the surface of graphene by the high surface area available. Interacting assemblies of aromatic molecules retained their strongly-shielded NMR signals and remained within self-assembled structures, with slower rates of diffusion from association with graphene, but with no further shielding from graphene. Binding to graphene was selective for positively-charged organic assemblies, weaker for non-aromatic and negligible for strongly-negatively-charged molecules, presumably repelled by a negative zeta potential of graphene in water. Stronger binders, or considerable excess of weaker binders readily reversed physisorption, with no evidence of structural changes from chemisorption. The fundamental nature of these different electronic interactions between organic and polyaromatic carbon is considered with relevance to electronics, charge storage, sensor, medical, pharmaceutical and environmental research.

Identification and subsequent phosphorylation of sequestered partially processed caseins in the lactating guinea-pig mammary gland.

PubMed Central

Boulton, A P; Pascall, J C; Craig, R K

1984-01-01

Golgi and endoplasmic-reticulum fractions were prepared from the lactating guinea-pig mammary gland. The endoplasmic-reticulum fraction was highly active in the processing and sequestration of milk-protein primary translation products. Explants from the lactating gland in organ culture were used to identify milk-protein intermediates present in the secretory pathway, and the timing of the events leading to their post-translational modification. With [35S]methionine, the milk proteins labelled after a short pulse (3 min) were represented by the partially processed (but not phosphorylated) caseins and alpha-lactalbumin sequestered within membrane-bound vesicles. After a 30 min labelling period, higher-Mr caseins with electrophoretic mobilities identical with those of the phosphorylated caseins isolated from milk were identified in the incubation medium, and sequestered within membrane-bound vesicles. Pulse-chase experiments established a precursor-product relationship between these forms. Secretion is apparent approx. 30 min after sequestration. Caseins are highly phosphorylated; removal of the phosphate residues with acid phosphatase results in proteins with increased electrophoretic mobility, similar to those of the partially processed early casein intermediates found sequestered in explants after a 3 min pulse with [35S]methionine, and those sequestered within microsomal membranes after mRNA-directed cell-free protein synthesis. A comparison of the proteins labelled during both short (5 min) and long (30 min) pulses with [35S]methionine and [32P]Pi shows that, in contrast with the 35S-labelled caseins, those labelled with [32P]Pi exhibit only electrophoretic mobilities identical with those of the mature caseins isolated from milk and those identified after long labelling periods with [35S]methionine. No phosphorylated early intermediate forms of caseins were identified. We conclude that the synthesis and post-translational modification of guinea-pig caseins occurs in two stages, (i) an early event involving synthesis and sequestration within the endoplasmic reticulum, an event that involves signal-peptide removal, followed (ii) 10-20 min later by phosphorylation at a different point in the secretory pathway, probably in the Golgi complex. Secretion of the phosphorylated caseins occurs 10-20 min later. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. PMID:6477529

Estimating genetic potential of biofuel forest hardwoods to withstand metal toxicity in industrial effluent under dry tropical conditions.

PubMed

Manzoor, S A; Mirza, S N; Zubair, M; Nouman, W; Hussain, S B; Mehmood, S; Irshad, A; Sarwar, N; Ammar, A; Iqbal, M F; Asim, A; Chattha, M U; Chattha, M B; Zafar, A; Abid, R

2015-08-14

Biofuel tree species are recognized as a promising alternative source of fuel to conventional forms. Additionally, these tree species are also effective in accumulating toxic heavy metals present in some industrial effluents. In developing countries such as Pakistan, the use of biofuel tree species is gaining popularity not only for harvesting economical and environmentally friendly biofuel, but also to sequester poisonous heavy metals from industrial wastewater. This study was aimed at evaluating the genetic potential of two biofuel species, namely, Jatropha curcas and Pongamia pinnata, to grow when irrigated with industrial effluent from the Pak-Arab Fertilizer Factory Multan, Southern Punjab, Pakistan. The growth performances of one-year-old seedlings of both species were compared in soil with adverse physiochemical properties. It was found that J. curcas was better able to withstand the toxicity of the heavy metals present in the fertilizer factory effluent. J. curcas showed maximum gain in height, diameter, and biomass production in soil irrigated with 75% concentrated industrial effluent. In contrast, P. pinnata showed a significant reduction in growth in soil irrigated with more than 50% concentrated industrial effluent, indicating that this species is less tolerant to higher toxicity levels of industrial effluent. This study identifies J. curcas as a promising biofuel tree species that can be grown using industrial wastewater.

Transfers and transformations of zinc in flow-through wetland microcosms.

PubMed

Gillespie, W B; Hawkins, W B; Rodgers, J H; Cano, M L; Dorn, P B

1999-06-01

Two microcosm-scale wetlands (570-liter containers) were integratively designed and constructed to investigate transfers and transformations of zinc associated with an aqueous matrix, and to provide future design parameters for pilot-scale constructed wetlands. The fundamental design of these wetland microcosms was based on biogeochemical principles regulating fate and transformations of zinc (pH, redox, etc.). Each wetland consisted of a 45-cm hydrosoil depth inundated with 25 cm of water, and planted with Scirpus californicus. Zinc ( approximately 2 mg/liter) as ZnCl2 was amended to each wetland for 62 days. Individual wetland hydraulic retention times (HRT) were approximately 24 h. Total recoverable zinc was measured daily in microcosm inflow and outflows, and zinc concentrations in hydrosoil and S. californicus tissue were measured pre- and post-treatment. Ceriodaphnia dubia and Pimephales promelas7-day aqueous toxicity tests were performed on wetland inflows and outflows, and Hyalella azteca whole sediment toxicity tests (10-day) were performed pre- and post-treatment. Approximately 75% of total recoverable zinc was transferred from the water column. Toxicity decreased from inflow to outflow based on 7-day C. dubia tests, and survival of H. azteca in hydrosoil was >80%. Data illustrate the ability of integratively designed wetlands to transfer and sequester zinc from the water column while concomitantly decreasing associated toxicity. Copyright 1999 Academic Press.

A Synthetic Circuit for Mercury Bioremediation Using Self-Assembling Functional Amyloids.

PubMed

Tay, Pei Kun R; Nguyen, Peter Q; Joshi, Neel S

2017-10-20

Synthetic biology approaches to bioremediation are a key sustainable strategy to leverage the self-replicating and programmable aspects of biology for environmental stewardship. The increasing spread of anthropogenic mercury pollution into our habitats and food chains is a pressing concern. Here, we explore the use of programmed bacterial biofilms to aid in the sequestration of mercury. We demonstrate that by integrating a mercury-responsive promoter and an operon encoding a mercury-absorbing self-assembling extracellular protein nanofiber, we can engineer bacteria that can detect and sequester toxic Hg 2+ ions from the environment. This work paves the way for the development of on-demand biofilm living materials that can operate autonomously as heavy-metal absorbents.

Iron Balance and the Role of Hepcidin in Chronic Kidney Disease

PubMed Central

Ganz, Tomas; Nemeth, Elizabeta

2016-01-01

Summary The hepatic iron-regulatory hormone hepcidin and its receptor, the cellular iron exporter ferroportin, constitute a feedback-regulated mechanism that maintains adequate plasma concentrations of iron-transferrin for erythropoiesis and other functions, ensures sufficient iron stores, and avoids iron toxicity and iron-dependent microbial pathogenesis. In chronic kidney disease, inflammation and impaired renal clearance increase plasma hepcidin, inhibiting duodenal iron absorption and sequestering iron in macrophages. These effects of hepcidin can cause systemic iron deficiency, decreased availability of iron for erythropoiesis, and resistance to endogenous and exogenous erythropoietin. Together with impaired renal production of erythropoietin, hepcidin-mediated iron restriction contributes to anemia of chronic kidney disease. PMID:27236128

Arsenic tolerance in Arabidopsis is mediated by two ABCC-type phytochelatin transporters

PubMed Central

Song, Won-Yong; Park, Jiyoung; Mendoza-Cózatl, David G.; Suter-Grotemeyer, Marianne; Shim, Donghwan; Hörtensteiner, Stefan; Geisler, Markus; Weder, Barbara; Rea, Philip A.; Rentsch, Doris; Schroeder, Julian I.; Lee, Youngsook; Martinoia, Enrico

2010-01-01

Arsenic is an extremely toxic metalloid causing serious health problems. In Southeast Asia, aquifers providing drinking and agricultural water for tens of millions of people are contaminated with arsenic. To reduce nutritional arsenic intake through the consumption of contaminated plants, identification of the mechanisms for arsenic accumulation and detoxification in plants is a prerequisite. Phytochelatins (PCs) are glutathione-derived peptides that chelate heavy metals and metalloids such as arsenic, thereby functioning as the first step in their detoxification. Plant vacuoles act as final detoxification stores for heavy metals and arsenic. The essential PC–metal(loid) transporters that sequester toxic metal(loid)s in plant vacuoles have long been sought but remain unidentified in plants. Here we show that in the absence of two ABCC-type transporters, AtABCC1 and AtABCC2, Arabidopsis thaliana is extremely sensitive to arsenic and arsenic-based herbicides. Heterologous expression of these ABCC transporters in phytochelatin-producing Saccharomyces cerevisiae enhanced arsenic tolerance and accumulation. Furthermore, membrane vesicles isolated from these yeasts exhibited a pronounced arsenite [As(III)]–PC2 transport activity. Vacuoles isolated from atabcc1 atabcc2 double knockout plants exhibited a very low residual As(III)–PC2 transport activity, and interestingly, less PC was produced in mutant plants when exposed to arsenic. Overexpression of AtPCS1 and AtABCC1 resulted in plants exhibiting increased arsenic tolerance. Our findings demonstrate that AtABCC1 and AtABCC2 are the long-sought and major vacuolar PC transporters. Modulation of vacuolar PC transporters in other plants may allow engineering of plants suited either for phytoremediation or reduced accumulation of arsenic in edible organs. PMID:21078981

Unexpected Interactions of the Cyanobacterial Metallothionein SmtA with Uranium.

PubMed

Acharya, Celin; Blindauer, Claudia A

2016-02-15

Molecules for remediating or recovering uranium from contaminated environmental resources are of high current interest, with protein-based ligands coming into focus recently. Metallothioneins either bind or redox-silence a range of heavy metals, conferring protection against metal stress in many organisms. Here, we report that the cyanobacterial metallothionein SmtA competes with carbonate for uranyl binding, leading to formation of heterometallic (UO2)(n)Zn4SmtA species, without thiol oxidation, zinc loss, or compromising secondary or tertiary structure of SmtA. In turn, only metalated and folded SmtA species were found to be capable of uranyl binding. (1)H NMR studies and molecular modeling identified Glu34/Asp38 and Glu12/C-terminus as likely adventitious, but surprisingly strong, bidentate binding sites. While it is unlikely that these interactions correspond to an evolved biological function of this metallothionein, their occurrence may offer new possibilities for designing novel multipurpose bacterial metallothioneins with dual ability to sequester both soft metal ions including Cu(+), Zn(2+), Cd(2+), Hg(2+), and Pb(2+) and hard, high-oxidation state heavy metals such as U(VI). The concomitant protection from the chemical toxicity of uranium may be valuable for the development of bacterial strains for bio-remediation.

Metabolic reengineering invoked by microbial systems to decontaminate aluminum: implications for bioremediation technologies.

PubMed

Auger, Christopher; Han, Sungwon; Appanna, Varun P; Thomas, Sean C; Ulibarri, Gerardo; Appanna, Vasu D

2013-01-01

As our reliance on aluminum (Al) increases, so too does its presence in the environment and living systems. Although generally recognized as safe, its interactions with most living systems have been nefarious. This review presents an overview of the noxious effects of Al and how a subset of microbes can rework their metabolic pathways in order to survive an Al-contaminated environment. For instance, in order to expulse the metal as an insoluble precipitate, Pseudomonas fluorescens shuttles metabolites toward the production of organic acids and lipids that play key roles in chelating, immobilizing and exuding Al. Further, the reconfiguration of metabolic modules enables the microorganism to combat the dearth of iron (Fe) and the excess of reactive oxygen species (ROS) promoted by Al toxicity. While in Rhizobium spp., exopolysaccharides have been invoked to sequester this metal, an ATPase is known to safeguard Anoxybacillus gonensis against the trivalent metal. Hydroxyl, carboxyl and phosphate moieties have also been exploited by microbes to trap Al. Hence, an understanding of the metabolic networks that are operative in microorganisms residing in polluted environments is critical in devising bioremediation technologies aimed at managing metal wastes. Metabolic engineering is essential in elaborating effective biotechnological processes to decontaminate metal-polluted surroundings. Copyright © 2012 Elsevier Inc. All rights reserved.

Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic

PubMed Central

2016-01-01

Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent’s molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent’s ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway. PMID:27175104

Behavioral and Chemical Ecology of Marine Organisms with Respect to Tetrodotoxin

PubMed Central

Williams, Becky L.

2010-01-01

The behavioral and chemical ecology of marine organisms that possess tetrodotoxin (TTX) has not been comprehensively reviewed in one work to date. The evidence for TTX as an antipredator defense, as venom, as a sex pheromone, and as an attractant for TTX-sequestering organisms is discussed. Little is known about the adaptive value of TTX in microbial producers; thus, I focus on what is known about metazoans that are purported to accumulate TTX through diet or symbioses. Much of what has been proposed is inferred based on the anatomical distribution of TTX. Direct empirical tests of these hypotheses are absent in most cases. PMID:20411104

Is climate change mitigation the best use of desert shrublands?

Treesearch

Susan E. Meyer

2011-01-01

In a world where the metrics of the carbon economy have become a major issue, it may come as a surprise that intact cold desert shrublands can sequester significant amounts of carbon, both as biomass and in the form of SOC (soil organic carbon). Xerophytic shrubs invest heavily in belowground biomass, placing fixed carbon in an environment where it turns over only very...

Differences in phytotoxicity and dissipation between ionized and nonionized oil sands naphthenic acids in wetland plants.

PubMed

Armstrong, Sarah A; Headley, John V; Peru, Kerry M; Germida, James J

2009-10-01

Naphthenic acids (NAs) are composed of alkyl-substituted acyclic and cycloaliphatic carboxylic acids and, because they are acutely toxic to fish, are of toxicological concern. During the caustic hot-water extraction of oil from the bitumen in oil sands deposits, NAs become concentrated in the resulting tailings pond water. The present study investigated if dissipation of NAs occurs in the presence of hydroponically grown emergent macrophytes (Typha latifolia, Phragmites australis, and Scirpus acutus) to determine the potential for phytoremediation of these compounds. Plants were grown with oil sands NAs (pKa approximately 5-6) in medium at pH 7.8 (predominantly ionized NAs) and pH 5.0 (predominantly nonionized NAs) to determine if, by altering their chemical form, NAs may be more accessible to plants and, thus, undergo increased dissipation. Whereas the oil sands NA mixture in its nonionized form was more toxic to wetland plants than its ionized form, neither form appeared to be sequestered by wetland plants. The present study demonstrated that plants may selectively enhance the dissipation of individual nonionized NA compounds, which contributes to toxicity reduction but does not translate into detectable total NA dissipation within experimental error and natural variation. Plants were able to reduce the toxicity of a NA system over 30 d, increasing the median lethal concentration (LC50; % of hydroponic solution) of the medium for Daphnia magna by 23.3% +/- 8.1% (mean +/- standard error; nonionized NAs) and 37.0% +/- 2.7% (ionized NAs) as determined by acute toxicity bioassays. This reduction in toxicity was 7.3% +/- 2.6% (nonionized NAs) and 45.0% +/- 6.8% (ionized NAs) greater than that in unplanted systems.

Cadmium and zinc activate adaptive mechanisms in Nicotiana tabacum similar to those observed in metal tolerant plants.

PubMed

Vera-Estrella, Rosario; Gómez-Méndez, María F; Amezcua-Romero, Julio C; Barkla, Bronwyn J; Rosas-Santiago, Paul; Pantoja, Omar

2017-09-01

Tobacco germinated and grew in the presence of high concentrations of cadmium and zinc without toxic symptoms. Evidence suggests that these ions are sequestered into the vacuole by heavy metal/H + exchanger mechanisms. Heavy metal hyperaccumulation and hypertolerance are traits shared by a small set of plants which show specialized physiological and molecular adaptations allowing them to accumulate and sequester toxic metal ions. Nicotiana tabacum was used to test its potential as a metal-accumulator in a glass house experiment. Seed germination was not affected in the presence of increasing concentrations of zinc and cadmium. Juvenile and adult plants could concentrate CdCl 2 and ZnSO 4 to levels exceeding those in the hydroponic growth medium and maintained or increased their leaf dry weight when treated with 0.5- or 1-mM CdCl 2 or 1-mM ZnSO 4 for 5 days. Accumulation of heavy metals did not affect the chlorophyll and carotenoid levels, while variable effects were observed in cell sap osmolarity. Heavy metal-dependent H + transport across the vacuole membrane was monitored using quinacrine fluorescence quenching. Cadmium- or zinc-dependent fluorescence recovery revealed that increasing concentrations of heavy metals stimulated the activities of the tonoplast Cd 2+ or Zn 2+ /H + exchangers. Immunodetection of the V-ATPase subunits showed that the increased proton transport by zinc was not due to changes in protein amount. MTP1 and MTP4 immunodetection and semiquantitative RT-PCR of NtMTP1, NtNRAMP1, and NtZIP1 helped to identify the genes that are likely involved in sequestration of cadmium and zinc in the leaf and root tissue. Finally, we demonstrated that cadmium and zinc treatments induced an accumulation of zinc in leaf tissues. This study shows that N. tabacum possesses a hyperaccumulation response, and thus could be used for phytoremediation purposes.

Agroforestry: working trees for sequestering carbon on agricultural lands

Treesearch

M.M. Schoeneberger

2008-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon while leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues facing these lands, such as economic diversification, biodiversity, and water quality....

Agroforestry-working trees for sequestering carbon on ag-lands

Treesearch

Michele M. Schoeneberger

2005-01-01

Agroforestry is an appealing option for sequestering carbon on agricultural lands because it can sequester significant amounts of carbon whle leaving the bulk of the land in agricultural production. Simultaneously, it can help landowners and society address many other issues, such as economic diversification, biodiversity, and water quality, facing these lands....

Cholesterol accumulation in tissues of the Niemann-pick type C mouse is determined by the rate of lipoprotein-cholesterol uptake through the coated-pit pathway in each organ.

PubMed

Xie, C; Turley, S D; Dietschy, J M

1999-10-12

Niemann-Pick type C (NPC) disease is associated with the accumulation of unesterified cholesterol in nearly all tissues and with progressive neurodegeneration. A murine model of this disease, the NPC mouse, was used to determine whether this sequestered cholesterol represented sterol carried in low density lipoprotein (LDL) and chylomicrons (CMs) taken up into the tissues through the coated-pit pathway. By 7 weeks of age, the sterol pool in the NPC mice had increased from 2,165 to 5,669 mg/kg body weight because of the daily sequestration of 67 mg of cholesterol per kg in the various organs. This was 7-fold greater than the rate of accumulation in control mice. The rate of LDL clearance in the NPC mouse was normal (523 ml/day per kg) and accounted for the uptake of 78 mg/day per kg of cholesterol in LDL whereas 8 mg/day per kg was taken up from CMs. Deletion of the LDL receptor in NPC mice altered the concentration of unesterified cholesterol in every organ in a manner consistent with the changes also observed in the rate of LDL cholesterol uptake in those tissues. Similarly, altering the flow of cholesterol to the liver through the CM pathway changed the concentration of unesterified cholesterol in that organ. Together, these observations strongly support the conclusion that, in NPC disease, it is cholesterol carried in LDL and CMs that is sequestered in the tissues and not sterol that is newly synthesized and carried in high density lipoprotein.

How and why do toxic conformers of aberrant proteins accumulate during ageing?

PubMed

Josefson, Rebecca; Andersson, Rebecca; Nyström, Thomas

2017-07-15

Ageing can be defined as a gradual decline in cellular and physical functions accompanied by an increased sensitivity to the environment and risk of death. The increased risk of mortality is causally connected to a gradual, intracellular accumulation of so-called ageing factors, of which damaged and aggregated proteins are believed to be one. Such aggregated proteins also contribute to several age-related neurodegenerative disorders e.g. Alzheimer's, Parkinson's, and Huntington's diseases, highlighting the importance of protein quality control (PQC) in ageing and its associated diseases. PQC consists of two interrelated systems: the temporal control system aimed at refolding, repairing, and/or removing aberrant proteins and their aggregates and the spatial control system aimed at harnessing the potential toxicity of aberrant proteins by sequestering them at specific cellular locations. The accumulation of toxic conformers of aberrant proteins during ageing is often declared to be a consequence of an incapacitated temporal PQC system-i.e. a gradual decline in the activity of chaperones and proteases. Here, we review the current knowledge on PQC in relation to ageing and highlight that the breakdown of both temporal and spatial PQC may contribute to ageing and thus comprise potential targets for therapeutic interventions of the ageing process. © 2017 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

The chaperonin CCT promotes the formation of fibrillar aggregates of γ-tubulin.

PubMed

Pouchucq, Luis; Lobos-Ruiz, Pablo; Araya, Gissela; Valpuesta, José María; Monasterio, Octavio

2018-04-01

The type II chaperonin CCT is involved in the prevention of the pathogenesis of numerous human misfolding disorders, as it sequesters misfolded proteins, blocks their aggregation and helps them to achieve their native state. In addition, it has been reported that CCT can prevent the toxicity of non-client amyloidogenic proteins by the induction of non-toxic aggregates, leading to new insight in chaperonin function as an aggregate remodeling factor. Here we add experimental evidence to this alternative mechanism by which CCT actively promotes the formation of conformationally different aggregates of γ-tubulin, a non-amyloidogenic CCT client protein, which are mediated by specific CCT-γ-tubulin interactions. The in vitro-induced aggregates were in some cases long fiber polymers, which compete with the amorphous aggregates. Direct injection of unfolded purified γ-tubulin into single-cell zebra fish embryos allowed us to relate this in vitro activity with the in vivo formation of intracellular aggregates. Injection of a CCT-binding deficient γ-tubulin mutant dramatically diminished the size of the intracellular aggregates, increasing the toxicity of the misfolded protein. These results point to CCT having a role in the remodeling of aggregates, constituting one of its many functions in cellular proteostasis. Copyright © 2018. Published by Elsevier B.V.

Hyalella IQ Toxicity Test{trademark} as a predictor of whole sediment toxicity with diversely contaminated sediments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, W.S.; Hayes, K.R.

1994-12-31

The IQ TOXICITY TEST{trademark} is a toxicity screening test that evaluates the organism`s galactosidase enzyme system functionality as a predictor of acute toxicity. Organisms are exposed to a potentially toxic solution for approximately one hour. Following the exposure, the organisms are exposed to a slurry of a galactoside sugar tagged with a fluorescent marker (methylumbelliferyl galactoside) for 15--20 minutes. A black light can then be used to examine whether the hemolymph of the organism contains free umbelliferone, which brightly fluoresces. The organisms are then scored as ``on`` or ``off`` with respect to free umbelliferone. This endpoint can then be usedmore » to calculate an EC50, which is comparable to a whole effluent, pure compound, or sediment toxicity test. Slightly different methodologies are used for different toxicity test organisms. The objective of this presentation is to discuss the use of the IQ{trademark} methodology with porewater extract exposures of the amphipod Hyalella azteca as a predictor of results of whole sediment toxicity tests. The results of over thirty 10 and 28-day whole sediment toxicity tests and the concurrent Hyalella azteca 10 TOXICITY TESTS{trademark} are compared and discussed. The use of screening tests as a reduced cost method for initial site assessment will be discussed.« less

The SEQUEST Family Tree

NASA Astrophysics Data System (ADS)

Tabb, David L.

2015-11-01

Since its introduction in 1994, SEQUEST has gained many important new capabilities, and a host of successor algorithms have built upon its successes. This Account and Perspective maps the evolution of this important tool and charts the relationships among contributions to the SEQUEST legacy. Many of the changes represented improvements in computing speed by clusters and graphics cards. Mass spectrometry innovations in mass accuracy and activation methods led to shifts in fragment modeling and scoring strategies. These changes, as well as the movement of laboratories and lab members, have led to great diversity among the members of the SEQUEST family.

New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

2011-06-22

Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (XAS), and was implemented at the site of a former uranium mill in Rifle, CO. Glass columns filled with bioactive Rifle sediments were deployed in wells in the contaminated Rifle aquifer and amendedmore » with a hexavalent uranium (U(VI)) stock solution to increase uranium concentration while maintaining field conditions. This sediment was harvested and XAS was utilized to analyze the oxidation state and local molecular structure of the uranium in sediment samples. Extended X-Ray Absorption Fine Structure (EXAFS) data was collected and compared to known uranium spectra to determine the local molecular structure of the uranium in the sediment. Fitting was used to determine that the field site sediments did not contain uraninite (UO{sub 2}), indicating that models based on bioreduction using pure bacterial cultures are not accurate for bioremediation in the field. Stability tests on the monomeric tetravalent uranium (U(IV)) produced by bioremediation are needed in order to assess the efficacy of acetate-stimulation bioremediation.« less

Does Diffusion Sequester Heavy Metals in Old Contamination Soils?

NASA Astrophysics Data System (ADS)

Ma, J.; Jennings, A. A.

2002-12-01

Old soil contamination refers to soil contamination that has aged over a long period of time. For example, at some brownfields, the soil heavy metal contamination can be one hundred or more years old. When contamination is young, the heavy metals are bound relatively weakly to the soil. However, the speciation and/or mechanisms of association evolve with aging into much more stable forms. It also appears that the metals migrate deeper into the bulk soil matrix where they are less available to participate in surface-related phenomena. Previous research showed elevated heavy metal extraction result after the soil was pulverized, with all other experiment conditions remaining unchanged. This indicates the presence of sequestered heavy metal contamination within the large soil particles (aggregate). The mechanisms of sequestering are uncertain, but diffusion appears to be a major factor. There are two possible pathways of diffusion that can account for heavy metal sequestering: solid-state diffusion through the bulk aggregate or liquid-phase diffusion through micro-pores within the aggregate structure. The second diffusion mechanism can be coupled with sorption (or other surface-related phenomena) on the pore walls. The remediation of sequestered heavy metals is also impacted by diffusion. Grinding a soil significantly reduces its average particle size. This exposes more of its internal bulk volume to extraction and results in much shorter diffusion pathway for the sequestered heavy metals to be released. Evidence has illustrated that this both improves remediation efficiency and provides a method by which the degree of sequestering can be quantified. This paper will present the results of ongoing research that is developing methods to identify the mechanisms of, quantify the magnitude of and determine the relative importance of (i.e. risk analysis) heavy metals sequestered in old contamination soils.

Target or barrier? The cell wall of early- and later-diverging plants vs cadmium toxicity: differences in the response mechanisms

PubMed Central

Parrotta, Luigi; Guerriero, Gea; Sergeant, Kjell; Cai, Giampiero; Hausman, Jean-Francois

2015-01-01

Increasing industrialization and urbanization result in emission of pollutants in the environment including toxic heavy metals, as cadmium and lead. Among the different heavy metals contaminating the environment, cadmium raises great concern, as it is ecotoxic and as such can heavily impact ecosystems. The cell wall is the first structure of plant cells to come in contact with heavy metals. Its composition, characterized by proteins, polysaccharides and in some instances lignin and other phenolic compounds, confers the ability to bind non-covalently and/or covalently heavy metals via functional groups. A strong body of evidence in the literature has shown the role of the cell wall in heavy metal response: it sequesters heavy metals, but at the same time its synthesis and composition can be severely affected. The present review analyzes the dual property of plant cell walls, i.e., barrier and target of heavy metals, by taking Cd toxicity as example. Following a summary of the known physiological and biochemical responses of plants to Cd, the review compares the wall-related mechanisms in early- and later-diverging land plants, by considering the diversity in cell wall composition. By doing so, common as well as unique response mechanisms to metal/cadmium toxicity are identified among plant phyla and discussed. After discussing the role of hyperaccumulators’ cell walls as a particular case, the review concludes by considering important aspects for plant engineering. PMID:25814996

Retention of Plasmodium falciparum ring-infected erythrocytes in the slow, open microcirculation of the human spleen.

PubMed

Safeukui, Innocent; Correas, Jean-Michel; Brousse, Valentine; Hirt, Déborah; Deplaine, Guillaume; Mulé, Sébastien; Lesurtel, Mickael; Goasguen, Nicolas; Sauvanet, Alain; Couvelard, Anne; Kerneis, Sophie; Khun, Huot; Vigan-Womas, Inès; Ottone, Catherine; Molina, Thierry Jo; Tréluyer, Jean-Marc; Mercereau-Puijalon, Odile; Milon, Geneviève; David, Peter H; Buffet, Pierre A

2008-09-15

The current paradigm in Plasmodium falciparum malaria pathogenesis states that young, ring-infected erythrocytes (rings) circulate in peripheral blood and that mature stages are sequestered in the vasculature, avoiding clearance by the spleen. Through ex vivo perfusion of human spleens, we examined the interaction of this unique blood-filtering organ with P falciparum-infected erythrocytes. As predicted, mature stages were retained. However, more than 50% of rings were also retained and accumulated upstream from endothelial sinus wall slits of the open, slow red pulp microcirculation. Ten percent of rings were retained at each spleen passage, a rate matching the proportion of blood flowing through the slow circulatory compartment established in parallel using spleen contrast-enhanced ultrasonography in healthy volunteers. Rings displayed a mildly but significantly reduced elongation index, consistent with a retention process, due to their altered mechanical properties. This raises the new paradigm of a heterogeneous ring population, the less deformable subset being retained in the spleen, thereby reducing the parasite biomass that will sequester in vital organs, influencing the risk of severe complications, such as cerebral malaria or severe anemia. Cryptic ring retention uncovers a new role for the spleen in the control of parasite density, opening novel intervention opportunities.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouser, Paula J.; N'Guessan, A. Lucie; Qafoku, Nikolla

The capacity for subsurface sediments to sequester metal contaminants, such as uranium (U), and retain them after bioremediation efforts are completed is critical to site stewardship. Sediments enriched in natural organic matter are capable of sequestering significant quantities of U, but may also serve as sources to the aquifer, contributing to plume persistence. Two types of sediments were compared to better understand the mechanisms contributing to the sequestration and release of U in the presence of organic matter. Artificially bioreduced sediments were retrieved from a field experimental plot previously stimulated with acetate while naturally bioreduced sediments were collected from amore » location enriched in organic matter but never subject to acetate amendment. Batch incubations demonstrated that the artificially bioreduced sediments were primed to rapidly remove uranium from the groundwater whereas naturally bioreduced sediments initially released a sizeable portion of sediment U before U(VI)-removal commenced. Column experiments confirmed that U release persisted for 65 pore volumes in naturally bioreduced sediments, demonstrating the sink-source behavior of this sediment. Acetate addition to artificially bioreduced sediments shifted the microbial community from one dominated by sulfate-reducing bacteria within Desulfobacteraceae to the iron-reducing family Geobacteraceae and Firmicutes during U(VI) reduction. In contrast, initial Geobacteraceae communities innaturally reduced sediments were replaced by clone sequences with similarity to opportunistic Pseudomonas spp. during U release, while U(VI) removal occurred concurrent with enrichment of Firmicutes. These investigations stress the importance of characterizing zones with heterogeneous carbon pools at U contaminated sites prior to the determination of a remedial strategy.« less

Effects of organic carbon sequestration strategies on soil enzymatic activities

NASA Astrophysics Data System (ADS)

Puglisi, E.; Suciu, N.; Botteri, L.; Ferrari, T.; Coppolecchia, D.; Trevisan, M.; Piccolo, A.

2009-04-01

Greenhouse gases emissions can be counterbalanced with proper agronomical strategies aimed at sequestering carbon in soils. These strategies must be tested not only for their ability in reducing carbon dioxide emissions, but also for their impact on soil quality: enzymatic activities are related to main soil ecological quality, and can be used as early and sensitive indicators of alteration events. Three different strategies for soil carbon sequestration were studied: minimum tillage, protection of biodegradable organic fraction by compost amendment and oxidative polimerization of soil organic matter catalyzed by biometic porfirins. All strategies were compared with a traditional agricultural management based on tillage and mineral fertilization. Experiments were carried out in three Italian soils from different pedo-climatic regions located respectively in Piacenza, Turin and Naples and cultivated with maize or wheat. Soil samples were taken for three consecutive years after harvest and analyzed for their content in phosphates, ß-glucosidase, urease and invertase. An alteration index based on these enzymatic activities levels was applied as well. The biomimetic porfirin application didn't cause changes in enzymatic activities compared to the control at any treatment or location. Enzymatic activities were generally higher in the minimum tillage and compost treatment, while differences between location and date of samplings were limited. Application of the soil alteration index based on enzymatic activities showed that soils treated with compost or subjected to minimum tillage generally have a higher biological quality. The work confirms the environmental sustainability of the carbon sequestering agronomical practices studied.

An Analysis of the Climate Change Mitigation Potential through Soil Organic Carbon Sequestration in a Corn Belt Watershed

NASA Astrophysics Data System (ADS)

Bhattarai, M. D.; Secchi, S.; Schoof, J. T.

2015-12-01

The sequestration of carbon constitutes one of major options in agricultural climate change land-based mitigation. We examined the carbon sequestration potential of alternative agricultural land uses in an intensively farmed Corn Belt watershed. We Used downscaled data from eight atmosphere-ocean general circulation models (AOGCMs) for a simulation period between 2015 and 2099 with three emission pathways reflecting low, medium and high greenhouse gas scenarios. The use of downscaled data, coupled with high resolution land use and soil data, can help policy makers and land managers better understand spatial and temporal impacts of climate change. We consider traditional practices such as no-till corn-soybean rotations and continuous corn and include also switchgrass, a bioenergy crop. Our results show that switching from conventional tillage continuous corn to no-till corn-soybean can sequester the equivalent of 156,000 MtCO2 of soil organic carbon with a sequestration rate of 2.38 MtCO2 ha-1 yr-1 for the simulated period. Our results also indicate that switchgrass can sequester the equivalent of 282,000 MtCO2 of soil organic carbon with a sequestration rate of 4.4 MtCO2 ha-1 yr-1 for the period. Our finding also suggests that while climate change impacts corn and soybean yields, it does not have a significant effect on switchgrass yields possibly due to carbon fertilization effect on switchgrass yields.

Modeling the influence of coupled mass transfer processes on mass flux downgradient of heterogeneous DNAPL source zones

NASA Astrophysics Data System (ADS)

Yang, Lurong; Wang, Xinyu; Mendoza-Sanchez, Itza; Abriola, Linda M.

2018-04-01

Sequestered mass in low permeability zones has been increasingly recognized as an important source of organic chemical contamination that acts to sustain downgradient plume concentrations above regulated levels. However, few modeling studies have investigated the influence of this sequestered mass and associated (coupled) mass transfer processes on plume persistence in complex dense nonaqueous phase liquid (DNAPL) source zones. This paper employs a multiphase flow and transport simulator (a modified version of the modular transport simulator MT3DMS) to explore the two- and three-dimensional evolution of source zone mass distribution and near-source plume persistence for two ensembles of highly heterogeneous DNAPL source zone realizations. Simulations reveal the strong influence of subsurface heterogeneity on the complexity of DNAPL and sequestered (immobile/sorbed) mass distribution. Small zones of entrapped DNAPL are shown to serve as a persistent source of low concentration plumes, difficult to distinguish from other (sorbed and immobile dissolved) sequestered mass sources. Results suggest that the presence of DNAPL tends to control plume longevity in the near-source area; for the examined scenarios, a substantial fraction (43.3-99.2%) of plume life was sustained by DNAPL dissolution processes. The presence of sorptive media and the extent of sorption non-ideality are shown to greatly affect predictions of near-source plume persistence following DNAPL depletion, with plume persistence varying one to two orders of magnitude with the selected sorption model. Results demonstrate the importance of sorption-controlled back diffusion from low permeability zones and reveal the importance of selecting the appropriate sorption model for accurate prediction of plume longevity. Large discrepancies for both DNAPL depletion time and plume longevity were observed between 2-D and 3-D model simulations. Differences between 2- and 3-D predictions increased in the presence of sorption, especially for the case of non-ideal sorption, demonstrating the limitations of employing 2-D predictions for field-scale modeling.

The Simplest Flowchart Stating the Mechanisms for Organic Xenobiotics-induced Toxicity: Can it Possibly be Accepted as a "Central Dogma" for Toxic Mechanisms?

PubMed

Park, Yeong-Chul; Lee, Sundong; Cho, Myung-Haing

2014-09-01

Xenobiotics causing a variety of toxicity in biological systems could be classified as two types, inorganic and organic chemicals. It is estimated that the organic xenobiotics are responsible for approximately 80~90% of chemical-induced toxicity in human population. In the class for toxicology, we have encountered some difficulties in explaining the mechanisms of toxicity caused especially by organic chemicals. Here, a simple flowchart was introduced for explaining the mechanism of toxicity caused by organic xenobiotics, as the central dogma of molecular biology. This flowchart, referred to as a central dogma, was described based on a view of various aspects as follows: direct-acting chemicals vs. indirect-acting chemicals, cytochrome P450-dependent vs. cytochrome P450-independent biotransformation, reactive intermediates, reactivation, toxicokinetics vs. toxicodynamics, and reversibility vs. irreversibility. Thus, the primary objective of this flowchart is to help better understanding of the organic xenobiotics-induced toxic mechanisms, providing a major pathway for toxicity occurring in biological systems.

Metal-organic framework templated synthesis of porous inorganic materials as novel sorbents

DOEpatents

Taylor-Pashow, Kathryn M. L.; Lin, Wenbin; Abney, Carter W.

2017-03-21

A novel metal-organic framework (MOF) templated process for the synthesis of highly porous inorganic sorbents for removing radionuclides, actinides, and heavy metals is disclosed. The highly porous nature of the MOFs leads to highly porous inorganic sorbents (such as oxides, phosphates, sulfides, etc) with accessible surface binding sites that are suitable for removing radionuclides from high level nuclear wastes, extracting uranium from acid mine drainage and seawater, and sequestering heavy metals from waste streams. In some cases, MOFs can be directly used for removing these metal ions as MOFs are converted to highly porous inorganic sorbents in situ.

Ultrapure laser-synthesized Si-based nanomaterials for biomedical applications: in vivo assessment of safety and biodistribution

PubMed Central

Baati, Tarek; Al-Kattan, Ahmed; Esteve, Marie-Anne; Njim, Leila; Ryabchikov, Yury; Chaspoul, Florence; Hammami, Mohamed; Sentis, Marc; Kabashin, Andrei V.; Braguer, Diane

2016-01-01

Si/SiOx nanoparticles (NPs) produced by laser ablation in deionized water or aqueous biocompatible solutions present a novel extremely promising object for biomedical applications, but the interaction of these NPs with biological systems has not yet been systematically examined. Here, we present the first comprehensive study of biodistribution, biodegradability and toxicity of laser-synthesized Si-SiOx nanoparticles using a small animal model. Despite a relatively high dose of Si-NPs (20 mg/kg) administered intravenously in mice, all controlled parameters (serum, enzymatic, histological etc.) were found to be within safe limits 3 h, 24 h, 48 h and 7 days after the administration. We also determined that the nanoparticles are rapidly sequestered by the liver and spleen, then further biodegraded and directly eliminated in urine without any toxicity effects. Finally, we found that intracellular accumulation of Si-NPs does not induce any oxidative stress damage. Our results evidence a huge potential in using these safe and biodegradable NPs in biomedical applications, in particular as vectors, contrast agents and sensitizers in cancer therapy and diagnostics (theranostics). PMID:27151839

Ultrapure laser-synthesized Si-based nanomaterials for biomedical applications: in vivo assessment of safety and biodistribution

NASA Astrophysics Data System (ADS)

Baati, Tarek; Al-Kattan, Ahmed; Esteve, Marie-Anne; Njim, Leila; Ryabchikov, Yury; Chaspoul, Florence; Hammami, Mohamed; Sentis, Marc; Kabashin, Andrei V.; Braguer, Diane

2016-05-01

Si/SiOx nanoparticles (NPs) produced by laser ablation in deionized water or aqueous biocompatible solutions present a novel extremely promising object for biomedical applications, but the interaction of these NPs with biological systems has not yet been systematically examined. Here, we present the first comprehensive study of biodistribution, biodegradability and toxicity of laser-synthesized Si-SiOx nanoparticles using a small animal model. Despite a relatively high dose of Si-NPs (20 mg/kg) administered intravenously in mice, all controlled parameters (serum, enzymatic, histological etc.) were found to be within safe limits 3 h, 24 h, 48 h and 7 days after the administration. We also determined that the nanoparticles are rapidly sequestered by the liver and spleen, then further biodegraded and directly eliminated in urine without any toxicity effects. Finally, we found that intracellular accumulation of Si-NPs does not induce any oxidative stress damage. Our results evidence a huge potential in using these safe and biodegradable NPs in biomedical applications, in particular as vectors, contrast agents and sensitizers in cancer therapy and diagnostics (theranostics).

Halite as a Methane Sequestration Host: A Possible Explanation for Periodic Methane Release on Mars, and a Surface-accessible Source of Ancient Martian Carbon

NASA Technical Reports Server (NTRS)

Fries, M. D.; Steele, Andrew; Hynek, B. M.

2015-01-01

We present the hypothesis that halite may play a role in methane sequestration on the martian surface. In terrestrial examples, halite deposits sequester large volumes of methane and chloromethane. Also, examples of chloromethane-bearing, approximately 4.5 Ga old halite from the Monahans meteorite show that this system is very stable unless the halite is damaged. On Mars, methane may be generated from carbonaceous material trapped in ancient halite deposits and sequestered. The methane may be released by damaging its halite host; either by aqueous alteration, aeolian abrasion, heating, or impact shock. Such a scenario may help to explain the appearance of short-lived releases of methane on the martian surface. The methane may be of either biogenic or abiogenic origin. If this scenario plays a significant role on Mars, then martian halite deposits may contain samples of organic compounds dating to the ancient desiccation of the planet, accessible at the surface for future sample return missions.

The effect of ocean acidification on carbon storage and sequestration in seagrass beds; a global and UK context.

PubMed

Garrard, Samantha L; Beaumont, Nicola J

2014-09-15

Ocean acidification will have many negative consequences for marine organisms and ecosystems, leading to a decline in many ecosystem services provided by the marine environment. This study reviews the effect of ocean acidification (OA) on seagrasses, assessing how this may affect their capacity to sequester carbon in the future and providing an economic valuation of these changes. If ocean acidification leads to a significant increase in above- and below-ground biomass, the capacity of seagrass to sequester carbon will be significantly increased. The associated value of this increase in sequestration capacity is approximately £500 and 600 billion globally between 2010 and 2100. A proportionally similar increase in carbon sequestration value was found for the UK. This study highlights one of the few positive stories for ocean acidification and underlines that sustainable management of seagrasses is critical to avoid their continued degradation and loss of carbon sequestration capacity. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Simplest Flowchart Stating the Mechanisms for Organic Xenobiotics-induced Toxicity: Can it Possibly be Accepted as a “Central Dogma” for Toxic Mechanisms?

PubMed Central

Lee, Sundong; Cho, Myung-Haing

2014-01-01

Xenobiotics causing a variety of toxicity in biological systems could be classified as two types, inorganic and organic chemicals. It is estimated that the organic xenobiotics are responsible for approximately 80~90% of chemical-induced toxicity in human population. In the class for toxicology, we have encountered some difficulties in explaining the mechanisms of toxicity caused especially by organic chemicals. Here, a simple flowchart was introduced for explaining the mechanism of toxicity caused by organic xenobiotics, as the central dogma of molecular biology. This flowchart, referred to as a central dogma, was described based on a view of various aspects as follows: direct-acting chemicals vs. indirect-acting chemicals, cytochrome P450-dependent vs. cytochrome P450-independent biotransformation, reactive intermediates, reactivation, toxicokinetics vs. toxicodynamics, and reversibility vs. irreversibility. Thus, the primary objective of this flowchart is to help better understanding of the organic xenobiotics-induced toxic mechanisms, providing a major pathway for toxicity occurring in biological systems. PMID:25343011

The Toxicity of Guanidine Nitrate to Freshwater Aquatic Organisms.

DTIC Science & Technology

1985-06-01

RD-Ri58 822 THE TOXICITY OF GUANIDINE NITRATE TO FRESHWATER AQUATIC i/1 ORGANISMS(U) ARMY MEDICAL BIOENGINEERING RESEARCH AND DEVELOPMENT LAB FORT...4. . ... AD-A158 822 A TECHNICAL REPORT 8504 THE TOXICITY OF GUJANIDINE NITRATE TO FRESHWATER AQUATIC ORGANISMS* WILLIAM H. van...TITLE (and Subtitle) 5. TYPE OF REPORT &PERIOD COVERED THE TOXICITY OF GUANIDINE NITRATE Technical Report TO FRESHWATER AQUATIC ORGANISMS Feb 1984 - Nov

Catalytic Bioscavengers Human Butyrylcholinesterase and Paraoxonase Sequestered to the Center for CNS

DTIC Science & Technology

2010-04-01

of radiolabeling fusion proteins without the denaturing effects coincident with oxidative radio-iodination associated with the chloramine T method...organ PS product = [(%ID/g)/AUC]*1000 Reportable Outcomes (1) The plasma concentration decay curve for AGT-185 is shown in Figure 1. The % of...injected dose (ID)/mL decreases rapidly in plasma following IV injection. This plasma decay curve was fit to the bi-exponential equation described above

To manage or not to manage: The role of silviculture in sequestering carbon in the specter of climate change

Treesearch

Jianwei Zhang; Robert F. Powers; Carl N. Skinner

2010-01-01

Forests and the soils beneath them are a major sink for atmospheric CO2 and play a significant role in offsetting CO2 emissions by converting CO2 into wood through photosynthesis and storing it for an extended period. However, forest fires counter carbon sequestration because pyrolysis converts organic C to CO and CO2, releasing decades or centuries of bound C to the...

A cadmium-transporting P1B-type ATPase in yeast Saccharomyces cerevisiae.

PubMed

Adle, David J; Sinani, Devis; Kim, Heejeong; Lee, Jaekwon

2007-01-12

Detoxification and homeostatic acquisition of metal ions are vital for all living organisms. We have identified PCA1 in yeast Saccharomyces cerevisiae as an overexpression suppressor of copper toxicity. PCA1 possesses signatures of a P1B-type heavy metal-transporting ATPase that is widely distributed from bacteria to humans. Copper resistance conferred by PCA1 is not dependent on catalytic activity, but it appears that a cysteine-rich region located in the N terminus sequesters copper. Unexpectedly, when compared with two independent natural isolates and an industrial S. cerevisiae strain, the PCA1 allele of the common laboratory strains we have examined possesses a missense mutation in a predicted ATP-binding residue conserved in P1B-type ATPases. Consistent with a previous report that identifies an equivalent mutation in a copper-transporting P1B-type ATPase of a Wilson disease patient, the PCA1 allele found in laboratory yeast strains is nonfunctional. Overexpression or deletion of the functional allele in yeast demonstrates that PCA1 is a cadmium efflux pump. Cadmium as well as copper and silver, but not other metals examined, dramatically increase PCA1 protein expression through post-transcriptional regulation and promote subcellular localization to the plasma membrane. Our study has revealed a novel metal detoxification mechanism in yeast mediated by a P1B-type ATPase that is unique in structure, substrate specificity, and mode of regulation.

Capturing Bioavailable Organic Contaminants for Phase II Whole Sediment Toxicity Identification Evaluations

EPA Science Inventory

In Phase I of whole sediment TIEs, causes of toxicity to freshwater and marine organisms are characterized into broad toxicant classes including ammonia, metals and organic chemicals. In the whole sediment Phase I TIEs performed so far, organic chemicals have been shown to be t...

Role of the plasma membrane H+-ATPase in the regulation of organic acid exudation under aluminum toxicity and phosphorus deficiency

PubMed Central

Yu, Wenqian; Kan, Qi; Zhang, Jiarong; Zeng, Bingjie; Chen, Qi

2016-01-01

Aluminum (Al) toxicity and phosphorus (P) deficiency are 2 major limiting factors for plant growth and crop production in acidic soils. Organic acids exuded from roots have been generally regarded as a major resistance mechanism to Al toxicity and P deficiency. The exudation of organic acids is mediated by membrane-localized OA transporters, such as ALMT (Al-activated malate transporter) and MATE (multidrug and toxic compound extrusion). Beside on up-regulation expression of organic acids transporter gene, transcriptional, translational and post-translational regulation of the plasma membrane H+-ATPase are also involved in organic acid release process under Al toxicity and P deficiency. This mini-review summarizes the current knowledge about this field of study on the role of the plasma membrane H+-ATPase in organic acid exudation under Al toxicity and P deficiency conditions. PMID:26713714

Role of the plasma membrane H(+)-ATPase in the regulation of organic acid exudation under aluminum toxicity and phosphorus deficiency.

PubMed

Yu, Wenqian; Kan, Qi; Zhang, Jiarong; Zeng, Bingjie; Chen, Qi

2016-01-01

Aluminum (Al) toxicity and phosphorus (P) deficiency are 2 major limiting factors for plant growth and crop production in acidic soils. Organic acids exuded from roots have been generally regarded as a major resistance mechanism to Al toxicity and P deficiency. The exudation of organic acids is mediated by membrane-localized OA transporters, such as ALMT (Al-activated malate transporter) and MATE (multidrug and toxic compound extrusion). Beside on up-regulation expression of organic acids transporter gene, transcriptional, translational and post-translational regulation of the plasma membrane H(+)-ATPase are also involved in organic acid release process under Al toxicity and P deficiency. This mini-review summarizes the current knowledge about this field of study on the role of the plasma membrane H(+)-ATPase in organic acid exudation under Al toxicity and P deficiency conditions.

Evolving Role of Passive Samplers in Whole Sediment Toxicity Identification Evaluations

EPA Science Inventory

In Phase I of whole sediment TIEs, causes of toxicity to freshwater and marine organisms are characterized into broad toxicant classes including ammonia, metals and organic chemicals. In Phase II of the TIE, the specific toxicants causing observed toxicity are identified. For a...

Effects-Directed Analysis of Dissolved Organic Compounds in Oil Sands Process-Affected Water.

PubMed

Morandi, Garrett D; Wiseman, Steve B; Pereira, Alberto; Mankidy, Rishikesh; Gault, Ian G M; Martin, Jonathan W; Giesy, John P

2015-10-20

Acute toxicity of oil sands process-affected water (OSPW) is caused by its complex mixture of bitumen-derived organics, but the specific chemical classes that are most toxic have not been demonstrated. Here, effects-directed analysis was used to determine the most acutely toxic chemical classes in OSPW collected from the world's first oil sands end-pit lake. Three sequential rounds of fractionation, chemical analysis (ultrahigh resolution mass spectrometry), and acute toxicity testing (96 h fathead minnow embryo lethality and 15 min Microtox bioassay) were conducted. Following primary fractionation, toxicity was primarily attributable to the neutral extractable fraction (F1-NE), containing 27% of original organics mass. In secondary fractionation, F1-NE was subfractionated by alkaline water washing, and toxicity was primarily isolated to the ionizable fraction (F2-NE2), containing 18.5% of the original organic mass. In the final round, chromatographic subfractionation of F2-NE2 resulted in two toxic fractions, with the most potent (F3-NE2a, 11% of original organic mass) containing predominantly naphthenic acids (O2(-)). The less-toxic fraction (F3-NE2b, 8% of original organic mass) contained predominantly nonacid species (O(+), O2(+), SO(+), NO(+)). Evidence supports naphthenic acids as among the most acutely toxic chemical classes in OSPW, but nonacidic species also contribute to acute toxicity of OSPW.

Small Molecule Recognition and Tools to Study Modulation of r(CGG)(exp) in Fragile X-Associated Tremor Ataxia Syndrome.

PubMed

Yang, Wang-Yong; He, Fang; Strack, Rita L; Oh, Seok Yoon; Frazer, Michelle; Jaffrey, Samie R; Todd, Peter K; Disney, Matthew D

2016-09-16

RNA transcripts containing expanded nucleotide repeats cause many incurable diseases via various mechanisms. One such disorder, fragile X-associated tremor ataxia syndrome (FXTAS), is caused by a noncoding r(CGG) repeat expansion (r(CGG)(exp)) that (i) sequesters proteins involved in RNA metabolism in nuclear foci, causing dysregulation of alternative pre-mRNA splicing, and (ii) undergoes repeat associated non-ATG translation (RANT), which produces toxic homopolymeric proteins without using a start codon. Here, we describe the design of two small molecules that inhibit both modes of toxicity and the implementation of various tools to study perturbation of these cellular events. Competitive Chemical Cross Linking and Isolation by Pull Down (C-Chem-CLIP) established that compounds bind r(CGG)(exp) and defined small molecule occupancy of r(CGG)(exp) in cells, the first approach to do so. Using an RNA GFP mimic, r(CGG)(exp)-Spinach2, we observe that our optimal designed compound binds r(CGG)(exp) and affects RNA localization by disrupting preformed RNA foci. These events correlate with an improvement of pre-mRNA splicing defects caused by RNA gain of function. In addition, the compounds reduced levels of toxic homopolymeric proteins formed via RANT. Polysome profiling studies showed that small molecules decreased loading of polysomes onto r(CGG)(exp), explaining decreased translation.

Identifying the causes of sediment-associated toxicity in urban waterways in South China: incorporating bioavailabillity-based measurements into whole-sediment toxicity identification evaluation.

PubMed

Yi, Xiaoyi; Li, Huizhen; Ma, Ping; You, Jing

2015-08-01

Sediments in urban waterways of Guangzhou, China, were contaminated by a variety of chemicals and showed prevalent toxicity to benthic organisms. A combination of whole-sediment toxicity identification evaluation (TIE) and bioavailability-based extraction was used to identify the causes of sediment toxicity. Of the 6 sediment samples collected, 4 caused 100% mortality to Chironomus dilutus in 10-d bioassays, and the potential toxicants were assessed using TIE in these sediments after dilution. The results of phase I characterization showed that organic contaminants were the principal contributors to the mortality of the midges in 2 sediments and that metals and organics jointly caused the mortality in the other 2 sediments. Ammonia played no role in the mortality for any samples. Conventional toxic unit analysis in phase II testing identified Cr, Cu, Ni, Pb, and Zn as the toxic metals, with cypermethrin, lambda-cyhalothrin, deltamethrin, and fipronils being the toxic organics. To improve the accuracy of identifying the toxicants, 4-step sequential extraction and Tenax extraction were conducted to analyze the bioavailability of the metals and organics, respectively. Bioavailable toxic unit analysis narrowed the list of toxic contributors, and the putative toxicants included 3 metals (Zn, Ni, and Pb) and 3 pesticides (cypermethrin, lambda-cyhalothrin, and fipronils). Metals contributed to the mortality in all sediments, but sediment dilution reduced the toxicity and confounded the characterization of toxicity contribution from metals in 2 sediments in phase I. Incorporating bioavailability-based measurements into whole-sediment TIE improved the accuracy of identifying the causative toxicants in urban waterways where multiple stressors occurred and contributed to sediment toxicity jointly. © 2015 SETAC.

Acute toxicity of anionic and non-ionic surfactants to aquatic organisms.

PubMed

Lechuga, M; Fernández-Serrano, M; Jurado, E; Núñez-Olea, J; Ríos, F

2016-03-01

The environmental risk of surfactants requires toxicity measurements. As different test organisms have different sensitivity to the toxics, it is necessary to establish the most appropriate organism to classify the surfactant as very toxic, toxic, harmful or safe, in order to establish the maximum permissible concentrations in aquatic ecosystems. We have determined the toxicity values of various anionic surfactants ether carboxylic derivatives using four test organisms: the freshwater crustacean Daphnia magna, the luminescent bacterium Vibrio fischeri, the microalgae Selenastrum capricornutum (freshwater algae) and Phaeodactylum tricornutum (seawater algae). In addition, in order to compare and classify the different families of surfactants, we have included a compilation of toxicity data of surfactants collected from literature. The results indicated that V. fischeri was more sensitive to the toxic effects of the surfactants than was D. magna or the microalgae, which was the least sensitive. This result shows that the most suitable toxicity assay for surfactants may be the one using V. fischeri. The toxicity data revealed considerable variation in toxicity responses with the structure of the surfactants regardless of the species tested. The toxicity data have been related to the structure of the surfactants, giving a mathematical relationship that helps to predict the toxic potential of a surfactant from its structure. Model-predicted toxicity agreed well with toxicity values reported in the literature for several surfactants previously studied. Predictive models of toxicity is a handy tool for providing a risk assessment that can be useful to establish the toxicity range for each surfactant and the different test organisms in order to select efficient surfactants with a lower impact on the aquatic environment. Copyright © 2015 Elsevier Inc. All rights reserved.

Chapter 6: Selenium Toxicity to Aquatic Organisms

EPA Science Inventory

This chapter addresses the characteristics and nature of organic selenium (Se) toxicity to aquatic organisms, based on the most current state of scientific knowledge. As such, the information contained in this chapter relates to the 'toxicity assessment' phase of aquatic ecologi...

[Effects of land use change on carbon storage in terrestrial ecosystem].

PubMed

Yang, Jingcheng; Han, Xingguo; Huang, Jianhui; Pan, Qingmin

2003-08-01

Terrestrial ecosystem is an important carbon pool, which plays a crucial role in carbon biogeochemical cycle. Human activities such as fossil fuel combustion and land use change have resulted in carbon fluxes from terrestrial ecosystem to the atmosphere, which increased the atmospheric CO2 concentration, and reinforced the greenhouse effect. Land use change affects the structure and function of the terrestrial ecosystem, which causes its change of carbon storage. To a great extent, the change of carbon storage lies in the type of ecosystem and the change of land use patterns. The conversion of forest to agricultural land and pasture causes a large reduction of carbon storage in vegetation and soil, and the decrease of soil carbon concentration is mainly caused by the reduction of detritus, the acceleration of soil organic matter decomposition, and the destroy of physical protection to organic matter due to agricultural practices. The loss of soil organic matter appears at the early stage after deforestation, and the loss rate is influenced by many factors and soil physical, chemical and biological processes. The conversion of agricultural land and pasture to forest and many conservative agricultural practices can sequester atmospheric carbon in vegetation and soil. Vegetation can sequester large amounts of carbon from atmosphere, while carbon accumulation in soil varies greatly because of farming history and soil spatial heterogeneity. Conservative agricultural practices such as no-tillage, reasonable cropping system, and fertilization can influence soil physical and chemical characters, plant growth, quality and quantity of stubble, and soil microbial biomass and its activity, and hence, maintain and increase soil carbon concentration.

Selenium-tolerant diamondback moth disarms hyperaccumulator plantdefense

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freeman, J.L.; Quinn, C.F.; Marcus, M.A.

2006-11-20

Background Some plants hyperaccumulate the toxic element selenium (Se) to extreme levels, up to 1% of dry weight. The function of this intriguing phenomenon is obscure. Results Here, we show that the Se in the hyperaccumulator prince's plume (Stanleya pinnata) protects it from caterpillar herbivory because of deterrence and toxicity. In its natural habitat, however, a newly discovered variety of the invasive diamondback moth (Plutella xylostella) has disarmed this elemental defense. It thrives on plants containing highly toxic Se levels and shows no oviposition or feeding deterrence, in contrast to related varieties. Interestingly, a Se-tolerant wasp (Diadegma insulare) was foundmore » to parasitize the tolerant moth. The insect's Se tolerance mechanism was revealed by X-ray absorption spectroscopy and liquid chromatography--mass spectroscopy, which showed that the Se-tolerant moth and its parasite both accumulate methylselenocysteine, the same form found in the hyperaccumulator plant, whereas related sensitive moths accumulate selenocysteine. The latter is toxic because of its nonspecific incorporation into proteins. Indeed, the Se-tolerant diamondback moth incorporated less Se into protein. Additionally, the tolerant variety sequestered Se in distinct abdominal areas, potentially involved in detoxification and larval defense to predators. Conclusions Although Se hyperaccumulation protects plants from herbivory by some invertebrates, it can give rise to the evolution of unique Se-tolerant herbivores and thus provide a portal for Se into the local ecosystem. In a broader context, this study provides insight into the possible ecological implications of using Se-enriched crops as a source of anti-carcinogenic selenocompounds and for the remediation of Se-polluted environments.« less

Necessity of toxicity assessment in Turkish industrial discharges (examples from metal and textile industry effluents).

PubMed

Sponza, Delia Teresa

2002-01-01

Toxicity of some organic and inorganic chemicals to microorganisms is an important consideration in assessing their environmental impact against their economic benefits. Microorganisms play an important role in several environmental processes, both natural and engineered. Some organic and inorganics at toxic levels have been detected in industrial discharges resulting in plant upsets and discharge permit violations. In addition to this, even though in some cases the effluent wastewater does not exceed the discharge limits, the results of toxicity tests show potential toxicity. Toxicity knowledge of effluents can benefit treatment plant operators in optimising plant operation, setting pre-treatment standards, and protecting receiving water quality and in establishing sewer discharge permits to safeguard the plant. In the Turkish regulations only toxicity dilution factor (TDF) with fish is part of the toxicity monitoring program of permissible wastewater discharge. In various countries, laboratory studies involving the use of different organisms and protocol for toxicity assessment was conducted involving a number of discharges. In this study, it was aimed to investigate the acute toxicity of textile and metal industry wastewaters by traditional and enrichment toxicity tests and emphasize the importance of toxicity tests in wastewater discharge regulations. The enrichment toxicity tests are novel applications and give an idea whether there is potential toxicity or growth limiting and stimulation conditions. Different organisms were used such as bacteria (Floc and Coliform bacteria) algae (Chlorella sp.). fish (Lepistes sp.) and protozoan (Vorticella sp.) to represent four tropic levels. The textile industry results showed acute toxicity for at least one organism in 8 out of 23 effluent samples. Acute toxicity for at least two organisms in 7 out of 23 effluent sampling was observed for the metal industry. The toxicity test results were assessed with chemical analyses such as COD, BOD, color and heavy metals. It was observed that the toxicity of the effluents could not be explained by using physicochemical analyses in 5 cases for metal and 4 cases for the textile industries. The results clearly showed that the use of bioassay tests produce additional information about the toxicity potential of industrial discharges and effluents.

Elucidating mechanisms of toxic action of dissolved organic chemicals in oil sands process-affected water (OSPW).

PubMed

Morandi, Garrett D; Wiseman, Steve B; Guan, Miao; Zhang, Xiaowei W; Martin, Jonathan W; Giesy, John P

2017-11-01

Oil sands process-affected water (OSPW) is generated during extraction of bitumen in the surface-mining oil sands industry in Alberta, Canada, and is acutely and chronically toxic to aquatic organisms. It is known that dissolved organic compounds in OSPW are responsible for most toxic effects, but knowledge of the specific mechanism(s) of toxicity, is limited. Using bioassay-based effects-directed analysis, the dissolved organic fraction of OSPW has previously been fractionated, ultimately producing refined samples of dissolved organic chemicals in OSPW, each with distinct chemical profiles. Using the Escherichia coli K-12 strain MG1655 gene reporter live cell array, the present study investigated relationships between toxic potencies of each fraction, expression of genes and characterization of chemicals in each of five acutely toxic and one non-toxic extract of OSPW derived by use of effects-directed analysis. Effects on expressions of genes related to response to oxidative stress, protein stress and DNA damage were indicative of exposure to acutely toxic extracts of OSPW. Additionally, six genes were uniquely responsive to acutely toxic extracts of OSPW. Evidence presented supports a role for sulphur- and nitrogen-containing chemical classes in the toxicity of extracts of OSPW. Copyright © 2017 Elsevier Ltd. All rights reserved.

EMISSIONS OF ORGANIC AIR TOXICS FROM OPEN BURNING

EPA Science Inventory

A detailed literature search was performed to collect and collate available data reporting emissions of toxic organic substances into the air from open burning sources. Availability of data varied according to the source and the class of air toxics of interest. Volatile organic c...

40 CFR 433.12 - Monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... toxic organic compounds used; the method of disposal used instead of dumping, such as reclamation... compliance with the permit limitation [or pretreatment standard] for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the...

40 CFR 433.12 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... toxic organic compounds used; the method of disposal used instead of dumping, such as reclamation... the permit limitation [or pretreatment standard] for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters...

40 CFR 433.12 - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... toxic organic compounds used; the method of disposal used instead of dumping, such as reclamation... compliance with the permit limitation [or pretreatment standard] for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the...

40 CFR 433.12 - Monitoring requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... toxic organic compounds used; the method of disposal used instead of dumping, such as reclamation... compliance with the permit limitation [or pretreatment standard] for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the...

Inorganic carbon and fossil organic carbon are source of bias for quantification of sequestered carbon in mine spoil

NASA Astrophysics Data System (ADS)

Vindušková, Olga; Frouz, Jan

2016-04-01

Carbon sequestration in mine soils has been studied as a possibility to mitigate the rising atmospheric CO2 levels and to improve mine soil quality (Vindu\\vsková and Frouz, 2013). Moreover, these soils offer an unique opportunity to study soil carbon dynamics using the chronosequence approach (using a set of sites of different age on similar parent material). However, quantification of sequestered carbon in mine soils is often complicated by fossil organic carbon (e.g., from coal or kerogen) or inorganic carbon present in the spoil. We present a methodology for quantification of both of these common constituents of mine soils. Our recommendations are based on experiments done on post-mining soils in Sokolov basin, Czech Republic. Here, fossil organic carbon is present mainly as kerogen Type I and II and represents 2-6 wt.% C in these soils. Inorganic carbon in these soils is present mainly as siderite (FeCO3), calcite (CaCO3), and dolomite (CaMg(CO3)2). All of these carbonates are often found in the overburden of coal seams thus being a common constituent of post-mining soils in the world. Vindu\\vsková O, Frouz J, 2013. Soil carbon accumulation after open-cast coal and oil shale mining in Northern Hemisphere: a quantitative review. ENVIRONMENTAL EARTH SCIENCES, 69: 1685-1698. Vindu\\vsková O, Dvořáček V, Prohasková A, Frouz J. 2014. Distinguishing recent and fossil organic matter - A critical step in evaluation of post-mining soil development - using near infrared spectroscopy. ECOLOGICAL ENGINEERING. 73: 643-648. Vindu\\vsková O, Sebag D, Cailleau G, Brus J, Frouz J. 2015. Methodological comparison for quantitative analysis of fossil and recently derived carbon in mine soils with high content of aliphatic kerogen. ORGANIC GEOCHEMISTRY, 89-90:14-22.

Linkage of genomic biomarkers to whole organism endpoints in a Toxicity Identification Evaluation (TIE).

EPA Science Inventory

Aquatic organisms are exposed to many toxic chemicals and interpreting the cause and effect relationships between occurrence and impairment is difficult. Toxicity Identification Evaluation (TIE) provides a systematic approach for identifying responsible toxicants. TIE relies on ...

Methylated silicates may explain the release of chlorinated methane from Martian soil

NASA Astrophysics Data System (ADS)

Bak, Ebbe N.; Jensen, Svend J. Knak; Nørnberg, Per; Finster, Kai

2016-01-01

The only organic compounds that have been detected in the Martian soil are simple chlorinated compounds released from heated surface material. However, the sources of the organic carbon are in dispute. Wind abraded silicates, which are widespread on the Martian surface, can sequester atmospheric methane which generates methylated silicates and thus could provide a mechanism for accumulation of reduced carbon in the surface soil. In this study we show that thermal volatilization of methylated silicates in the presence of perchlorate leads to the production of chlorinated methane. Thus, methylated silicates could be a source of the organic carbon released as chlorinated methane upon thermal volatilization of Martian soil samples. Further, our experiments show that the ratio of the different chlorinated compounds produced is dependent on the mass ratio of perchlorate to organic carbon in the soil.

40 CFR 413.03 - Monitoring requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... standard for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping... monitoring report. I further certify that this facility is implementing the toxic organic management plan... POTWs shall submit a toxic organic management plan that specifies to the control authority's...

The Potential for Carbon Sequestration in the United States

DTIC Science & Technology

2007-09-01

Potential of U.S. Cropland to Sequester Carbon and Mitigate the Greenhouse Effect (Ann Arbor, Mich.: Ann Arbor Press, 1998), pp. 18–21; R.F. Follett and...others, The Potential of U.S. Grazing Land to Sequester Carbon and Mitigate the Greenhouse Effect (Boca Raton, Fla.: CRC Press, 2001), pp. 401–430... the Greenhouse Effect , pp. 18–21; R. Lal and others, “Managing U.S. Cropland to Sequester Carbon in Soil,” Journal of Soil and Water Conservation

TOXICITY CHARACTERIZATION PROCEDURES FOR ORGANIC TOXICANTS IN BULK SEDIMENTS

EPA Science Inventory

We have been pursuing development of toxicant characterization, isolation, and identification procedures for organic toxicants that can be applied in the context of 10-d solid-phase sediment tests measuring survival and growth of freshwater in the context of 10-d solid-phase sedi...

AJUBA LIM Proteins Limit Hippo Activity in Proliferating Cells by Sequestering the Hippo Core Kinase Complex in the Cytosol.

PubMed

Jagannathan, Radhika; Schimizzi, Gregory V; Zhang, Kun; Loza, Andrew J; Yabuta, Norikazu; Nojima, Hitoshi; Longmore, Gregory D

2016-10-15

The Hippo pathway controls organ growth and is implicated in cancer development. Whether and how Hippo pathway activity is limited to sustain or initiate cell growth when needed is not understood. The members of the AJUBA family of LIM proteins are negative regulators of the Hippo pathway. In mammalian epithelial cells, we found that AJUBA LIM proteins limit Hippo regulation of YAP, in proliferating cells only, by sequestering a cytosolic Hippo kinase complex in which LATS kinase is inhibited. At the plasma membranes of growth-arrested cells, AJUBA LIM proteins do not inhibit or associate with the Hippo kinase complex. The ability of AJUBA LIM proteins to inhibit YAP regulation by Hippo and to associate with the kinase complex directly correlate with their capacity to limit Hippo signaling during Drosophila wing development. AJUBA LIM proteins did not influence YAP activity in response to cell-extrinsic or cell-intrinsic mechanical signals. Thus, AJUBA LIM proteins limit Hippo pathway activity in contexts where cell proliferation is needed. Copyright © 2016 Jagannathan et al.

AJUBA LIM Proteins Limit Hippo Activity in Proliferating Cells by Sequestering the Hippo Core Kinase Complex in the Cytosol

PubMed Central

Jagannathan, Radhika; Schimizzi, Gregory V.; Zhang, Kun; Loza, Andrew J.; Yabuta, Norikazu; Nojima, Hitoshi

2016-01-01

The Hippo pathway controls organ growth and is implicated in cancer development. Whether and how Hippo pathway activity is limited to sustain or initiate cell growth when needed is not understood. The members of the AJUBA family of LIM proteins are negative regulators of the Hippo pathway. In mammalian epithelial cells, we found that AJUBA LIM proteins limit Hippo regulation of YAP, in proliferating cells only, by sequestering a cytosolic Hippo kinase complex in which LATS kinase is inhibited. At the plasma membranes of growth-arrested cells, AJUBA LIM proteins do not inhibit or associate with the Hippo kinase complex. The ability of AJUBA LIM proteins to inhibit YAP regulation by Hippo and to associate with the kinase complex directly correlate with their capacity to limit Hippo signaling during Drosophila wing development. AJUBA LIM proteins did not influence YAP activity in response to cell-extrinsic or cell-intrinsic mechanical signals. Thus, AJUBA LIM proteins limit Hippo pathway activity in contexts where cell proliferation is needed. PMID:27457617

Biochar, compost and biochar-compost blend as options to recover nutrients and sequester carbon.

PubMed

Oldfield, Thomas L; Sikirica, Nataša; Mondini, Claudio; López, Guadalupe; Kuikman, Peter J; Holden, Nicholas M

2018-07-15

This work assessed the potential environmental impact of recycling organic materials in agriculture via pyrolysis (biochar) and composting (compost), as well its combination (biochar-compost blend) versus business-as-usual represented by mineral fertiliser. Life cycle assessment methodology was applied using data sourced from experiments (FP7 project Fertiplus) in three countries (Spain, Italy and Belgium), and considering three environmental impact categories, (i) global warming; (ii) acidification and (iii) eutrophication. The novelty of this analysis is the inclusion of the biochar-compost blend with a focus on multiple European countries, and the inclusion of the acidification and eutrophication impact categories. Biochar, compost and biochar-compost blend all resulted in lower environmental impacts than mineral fertiliser from a systems perspective. Regional differences were found between biochar, compost and biochar-compost blend. The biochar-compost blend offered benefits related to available nutrients and sequestered C. It also produced yields of similar magnitude to mineral fertiliser, which makes its acceptance by farmers more likely whilst reducing environmental impacts. However, careful consideration of feedstock is required. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transition metals at the host–pathogen interface: How Neisseria exploit human metalloproteins for acquiring iron and zinc

PubMed Central

Neumann, Wilma; Hadley, Rose C.; Nolan, Elizabeth M.

2017-01-01

Transition metals are essential nutrients for all organisms and important players in the host-microbe interaction. During bacterial infection, a tug-of-war between the host and microbe for nutrient metals occurs: the host innate immune system responds to the pathogen by reducing metal availability and the pathogen tries to outmaneuver this response. The outcome of this competition, which involves metal-sequestering host-defense proteins and microbial metal acquisition machinery, is an important variable for whether infection occurs. One strategy bacterial pathogens employ to overcome metal restriction involves hijacking abundant host metalloproteins. The obligate human pathogens Neisseria spp. express TonB-dependent transport systems that capture human metalloproteins, extract the bound metal ions, and deliver these nutrients into the bacterial cell. This Essay highlights structural and mechanistic investigations that provide insights into how Neisseria acquire iron from the Fe(III)-transport protein transferrin, the Fe(III)-chelating host-defense protein lactoferrin, and the oxygen-transport protein hemoglobin, and obtain zinc from the metal-sequestering antimicrobial protein calprotectin. PMID:28487398

METHOD FOR TESTING THE AQUATIC TOXICITY OF SEDIMENT EXTRACTS FOR USE IN IDENTIFYING ORGANIC TOXICANTS IN SEDIMENTS

EPA Science Inventory

Biologically-directed fractionation techniques are a fundamental tool for identifying the cause of toxicity in environmental samples, but few are available for studying mixtures of organic chemicals in aquatic sediments. This paper describes a method for extracting organic chemic...

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2010 CFR

2010-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene production wastes. (a) Effective December 19, 1994, the wastes specified in 40...

Plant-Associated Bacterial Degradation of Toxic Organic Compounds in Soil

PubMed Central

McGuinness, Martina; Dowling, David

2009-01-01

A number of toxic synthetic organic compounds can contaminate environmental soil through either local (e.g., industrial) or diffuse (e.g., agricultural) contamination. Increased levels of these toxic organic compounds in the environment have been associated with human health risks including cancer. Plant-associated bacteria, such as endophytic bacteria (non-pathogenic bacteria that occur naturally in plants) and rhizospheric bacteria (bacteria that live on and near the roots of plants), have been shown to contribute to biodegradation of toxic organic compounds in contaminated soil and could have potential for improving phytoremediation. Endophytic and rhizospheric bacterial degradation of toxic organic compounds (either naturally occurring or genetically enhanced) in contaminated soil in the environment could have positive implications for human health worldwide and is the subject of this review. PMID:19742157

One Dimensional Coordination Polymer of Zn(II) for Developing Multifunctional Nanoparticles.

PubMed

Agarwal, Rashmi A

2017-10-16

A variety of nanoparticles (NPs) including Ag, Au, Pd, Cr and mixed Cu/Fe have been synthesized in a non-activated (without solvent removal) one dimensional coordination polymer (CP) of Zn(II) via two different mechanisms, acid formation and redox activity of the framework. Main driving force to grow these NPs within the cavities of CP is the presence of free oxygens of one of the monodentate carboxylate groups of BDC ligand. These free oxygens act as anchoring sites for the metal ions of the metal precursors. Chemical and physical characteristics of the NPs within the framework have been evaluated by the high resolution transmission electron microscopic (HRTEM) images. Excluding Ag(0) and Pd(0) other NPs are present as combinations of their elemental as well as oxide forms (Au/Au 2 O 3 , Cr/Cr 2 O 3 /CrO 2 and Cu/Cu 2 O, Fe/FeO). Synthesized Ag NPs within the framework show remarkable antibacterial efficacy at extremely low concentrations. Ag, Au and Cu/Fe NPs show ferromagnetic properties within the framework at room temperature. This polymer has potential to sequester highly toxic Cr(VI) to non toxic Cr(0), Cr(III) and Cr(IV) species.

Hexanucleotide Repeats in ALS/FTD Form Length-Dependent RNA Foci, Sequester RNA Binding Proteins, and Are Neurotoxic

PubMed Central

Lee, Youn-Bok; Chen, Han-Jou; Peres, João N.; Gomez-Deza, Jorge; Attig, Jan; Štalekar, Maja; Troakes, Claire; Nishimura, Agnes L.; Scotter, Emma L.; Vance, Caroline; Adachi, Yoshitsugu; Sardone, Valentina; Miller, Jack W.; Smith, Bradley N.; Gallo, Jean-Marc; Ule, Jernej; Hirth, Frank; Rogelj, Boris; Houart, Corinne; Shaw, Christopher E.

2013-01-01

Summary The GGGGCC (G4C2) intronic repeat expansion within C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Intranuclear neuronal RNA foci have been observed in ALS and FTD tissues, suggesting that G4C2 RNA may be toxic. Here, we demonstrate that the expression of 38× and 72× G4C2 repeats form intranuclear RNA foci that initiate apoptotic cell death in neuronal cell lines and zebrafish embryos. The foci colocalize with a subset of RNA binding proteins, including SF2, SC35, and hnRNP-H in transfected cells. Only hnRNP-H binds directly to G4C2 repeats following RNA immunoprecipitation, and only hnRNP-H colocalizes with 70% of G4C2 RNA foci detected in C9ORF72 mutant ALS and FTD brain tissues. We show that expanded G4C2 repeats are potently neurotoxic and bind hnRNP-H and other RNA binding proteins. We propose that RNA toxicity and protein sequestration may disrupt RNA processing and contribute to neurodegeneration. PMID:24290757

Analysis and prediction of structure-reactive toxicity relationships of substituted aromatic compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Z.T.; Wang, L.S.; Chen, S.P.

1996-12-31

The fundamental differentiation of toxicity is between reactive and nonreactive toxicity. Reactive toxicity is associated with a specific mechanism for the reaction with an enzyme or inhibition of a metabolic pathway, and nonreactive toxicity is related directly to the quantity of toxicant acting upon the cell. The quantitative structure-activity relationships (QSARs) have been successfully used in the nonreactive toxicity, such as prediction of the toxicity of nonreactive compounds based on their solubility in the lipids of organisms. The elements of molecular structure that are most closely related to nonreactive toxicity are those that describe the partitioning of the toxicant intomore » the organism, while QSARs for the reactive toxicity are less common in the environmental toxicology literature. With the recent increase in the use of synthetic substituted benzenes as industrial chemicals, the accurate analysis of the effect of reactive toxic chemicals has become recognized with QSAR. For this purpose, we selected the fish (Carassias auratus) as the test organism, measured the acute toxicity of 50% lethal concentration (LC{sub 50}) of the chemicals and the adenosine triphosphate (ATP) content of the liver cells for the organism. These determined the relationships of the acute toxicity of some substituted benzenes with their physicochemical structural parameters. The effects on the ATP content was also compared to predict biological reactivities of the chemicals, so as to find some clues to explain the mode of mechanism of the toxicity. 17 refs., 1 tab.« less

Organic matter and soil structure in the Everglades Agricultural Area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, Alan L.; Hanlon, Edward A.

This publication pertains to management of organic soils (Histosols) in the Everglades Agricultural Area (EAA). These former wetland soils are a major resource for efficient agricultural production and are important globally for their high organic matter content. Recognition of global warming has led to considerable interest in soils as a repository for carbon. Soils rich in organic matter essentially sequester or retain carbon in the profile and can contribute directly to keeping that sequestered carbon from entering the atmosphere. Identification and utilization of management practices that minimize the loss of carbon from organic soils to the atmosphere can minimize effectsmore » on global warming and increase the longevity of subsiding Histosols for agricultural use. Understanding and predicting how these muck soils will respond to current and changing land uses will help to manage soil carbon. The objectives of this document are to: a. Discuss organic soil oxidation relative to storing or releasing carbon and nitrogen b. Evaluate effects of cultivation (compare structure for sugarcane vs. uncultivated soil) Based upon the findings from the land-use comparison (sugarcane or uncultivated), organic carbon was higher with cultivation in the lower depths. There is considerable potential for minimum tillage and residue management to further enhance carbon sequestration in the sugarcane system. Carbon sequestration is improved and soil subsidence is slowed with sugarcane production, and both of these are positive outcomes. Taking action to increase or maintain carbon sequestration appears to be appropriate but may introduce some risk to farming operations. Additional management methods are needed to reduce this risk. For both the longevity of these organic soils and from a global perspective, slowing subsidence through BMP implementation makes sense. Since these BMPs also have considerable societal benefit, it remains to be seen if society will help to offset a part or all of the additional risk through some form of cost-sharing program or carbon credits trading. In general, the subsidence throughout the EAA has been slowed because of higher water table management and implementation of other selected BMPs. In addition, the comparison of soil with different land uses shows that the humification rate, conversion of organic matter from peat to humus, has changed. Another likely factor is a relative increase in the mineral content of soil as the organic constituents are lost through subsidence.« less

Effect of cholecalciferol on cadmium uptake in the chick

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cousins, R.J.; Feldman, S.L.

1973-12-01

The influence of vitamin D/sub 3/ (cholecalciferol) on the uptake of orally administered /sup 109/Cd into the principle cadmium sequestering organs, i.e. liver and kidney, was investigated in the vitamin D-deficient chick. Neither 2000 IU of vitamin D/sub 3/ administered orally nor dietary vitamin D/sub 3/ (600IU/kg) fed for four days significantly influenced the uptake of /sup 109/Cd. The vitamin did elevate the serum Ca concentration in the treated chicks.

Evaluation of ability of reference toxicity tests to identify stress in laboratory populations of the amphipod Hyalella azteca

USGS Publications Warehouse

McNulty, E.W.; Dwyer, F.J.; Ellersieck, Mark R.; Greer, E.I.; Ingersoll, C.G.; Rabeni, C.F.

1999-01-01

Standard methods for conducting toxicity tests imply that the condition of test organisms can be established using reference toxicity tests. However, only a limited number of studies have evaluated whether reference toxicity tests can actually be used to determine if organisms are in good condition at the start of a test. We evaluated the ability of reference toxicants to identify stress associated with starvation in laboratory populations of the amphipod Hyalella azteca using acute toxicity tests and four reference toxicants: KCl, CdCl2, sodium pentachlorophenate (NaPCP), and carbaryl. Stress associated with severe starvation was observed with exposure of amphipods to carbaryl or NaPCP but not with exposure to KCl or CdCl2 (i.e., lower LC50 with severe starvation). Although the LC50s for NaPCP and carbaryl were statistically different between starved and fed amphipods, this difference may not be biologically significant given the variability expected in acute lethality tests. Stress associated with sieving, heat shock, or cold shock of amphipods before the start of a test was not evident with exposure to carbaryl or KCl as reference toxicants. The chemicals evaluated in this study provided minimal information about the condition of the organisms used to start a toxicity test. Laboratories should periodically perform reference toxicity tests to assess the sensitivity of life stages or strains of test organisms. However, use of other test acceptability criteria required in standard methods such as minimum survival, growth, or reproduction of organisms in the control treatment at the end of a test, provides more useful information about the condition of organisms used to start a test compared to data generated from reference toxicity tests.

Bioavailability and mobility of organic contaminants in soil: new three-step ecotoxicological evaluation.

PubMed

Prokop, Zbyněk; Nečasová, Anežka; Klánová, Jana; Čupr, Pavel

2016-03-01

A novel approach was developed for rapid assessment of bioavailability and potential mobility of contaminants in soil. The response of the same test organism to the organic extract, water extract and solid phase of soil was recorded and compared. This approach was designed to give an initial estimate of the total organic toxicity (response to organic extractable fraction), as well as the mobile (response to water extract) and bioavailable fraction (response to solid phase) of soil samples. Eighteen soil samples with different levels of pollution and content of organic carbon were selected to validate the novel three-step ecotoxicological evaluation approach. All samples were chemically analysed for priority contaminants, including aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane (HCH) and dichlordiphenyltrichloroethane (DDT). The ecotoxicological evaluation involved determination of toxicity of the organic, mobile and bioavailable fractions of soil to the test organism, bacterium Bacillus cereus. We found a good correlation between the chemical analysis and the toxicity of organic extract. The low toxicity of water extracts indicated low water solubility, and thus, low potential mobility of toxic contaminants present in the soil samples. The toxicity of the bioavailable fraction was significantly greater than the toxicity of water-soluble (mobile) fraction of the contaminants as deduced from comparing untreated samples and water extracts. The bioavailability of the contaminants decreased with increasing concentrations of organic carbon in evaluated soil samples. In conclusion, the three-step ecotoxicological evaluation utilised in this study can give a quick insight into soil contamination in context with bioavailability and mobility of the contaminants present. This information can be useful for hazard identification and risk assessment of soil-associated contaminants. Graphical Abstract New three-step ecotoxicological evaluation by using the same organism.

Apparatus for extracting and sequestering carbon dioxide

DOEpatents

Rau, Gregory H [Castro Valley, CA; Caldeira, Kenneth G [Livermore, CA

2010-02-02

An apparatus and method associated therewith to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said apparatus hydrates CO.sub.2 and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Method for extracting and sequestering carbon dioxide

DOEpatents

Rau, Gregory H.; Caldeira, Kenneth G.

2005-05-10

A method and apparatus to extract and sequester carbon dioxide (CO.sub.2) from a stream or volume of gas wherein said method and apparatus hydrates CO.sub.2, and reacts the resulting carbonic acid with carbonate. Suitable carbonates include, but are not limited to, carbonates of alkali metals and alkaline earth metals, preferably carbonates of calcium and magnesium. Waste products are metal cations and bicarbonate in solution or dehydrated metal salts, which when disposed of in a large body of water provide an effective way of sequestering CO.sub.2 from a gaseous environment.

Field monitoring of toxic organic pollution in the sediments of Pearl River estuary and its tributaries.

PubMed

Fu, J; Wang, Z; Mai, B; Kang, Y

2001-01-01

Field monitoring of the toxic organic compounds (PCBs, PAHs, organochlorine pesticides) in the top sediments of Pearl River Estuary and its up-streams were made. It was found that the highest concentrations of these toxic organic compounds occurred in the sediment sampled at Macau inner harbor (ZB013), which is a sink of suspended fine particles transported from the upstream waterways. Because of the affinity of the hydrophobic organic compounds (PAHs, PCBs) for the solid phase, these fine particle depositions led to accumulation of these compounds in the sediment of Macau. The atmospheric dry deposition may be another source of the toxic organic pollution in the sediment.

On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

NASA Astrophysics Data System (ADS)

Hombegowda, H. C.; van Straaten, O.; Köhler, M.; Hölscher, D.

2016-01-01

Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is influenced by the type of the agroforestry system established, the soil and climatic conditions, and management. In this regional-scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): home garden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across 4 climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference, an agriculture reference and two of the same AFS types of two ages (30-60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50-61 %) in the top meter of soil depending on the climate zone. The establishment of home garden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture SOC stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in home garden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

On the rebound: soil organic carbon stocks can bounce back to near forest levels when agroforests replace agriculture in southern India

NASA Astrophysics Data System (ADS)

Hombegowda, H. C.; van Straaten, O.; Köhler, M.; Hölscher, D.

2015-08-01

Tropical agroforestry has an enormous potential to sequester carbon while simultaneously producing agricultural yields and tree products. The amount of soil organic carbon (SOC) sequestered is however influenced by the type of the agroforestry system established, the soil and climatic conditions and management. In this regional scale study, we utilized a chronosequence approach to investigate how SOC stocks changed when the original forests are converted to agriculture, and then subsequently to four different agroforestry systems (AFSs): homegarden, coffee, coconut and mango. In total we established 224 plots in 56 plot clusters across four climate zones in southern India. Each plot cluster consisted of four plots: a natural forest reference plot, an agriculture reference and two of the same AFS types of two ages (30-60 years and > 60 years). The conversion of forest to agriculture resulted in a large loss the original SOC stock (50-61 %) in the top meter of soil depending on the climate zone. The establishment of homegarden and coffee AFSs on agriculture land caused SOC stocks to rebound to near forest levels, while in mango and coconut AFSs the SOC stock increased only slightly above the agriculture stock. The most important variable regulating SOC stocks and its changes was tree basal area, possibly indicative of organic matter inputs. Furthermore, climatic variables such as temperature and precipitation, and soil variables such as clay fraction and soil pH were likewise all important regulators of SOC and SOC stock changes. Lastly, we found a strong correlation between tree species diversity in homegarden and coffee AFSs and SOC stocks, highlighting possibilities to increase carbon stocks by proper tree species assemblies.

Toxic effects of lead on biochemical and histological alterations in green mussel (Perna viridis) induced by environmentally relevant concentrations.

PubMed

Hariharan, G; Purvaja, R; Ramesh, R

2014-01-01

Acute and chronic toxicity tests were conducted on green mussel (Perna viridis) to determine the adverse effects of lead (Pb). Exposure of organisms to acute toxicity test for 96 h and lethal concentration (LC(50)) was the endpoint of the test. Acute toxicity for 96-h LC(50) and 95% confidence intervals of P. viridis was 2.62 ± 0.12 (2.62-3.24) mg/L Pb. Chronic toxicity tests revealed that survival of exposed organisms decreased with elevated exposure concentrations. No-observed-effect concentration (NOEC) and lowest-observed-effect concentration (LOEC) were calculated based on survival of test organisms. Results of this study demonstrated an increase in toxicity in test organisms with rise in exposure time and concentration. In this study, histology and biochemical enzymes, namely, catalase, reduced glutathione, glutathione S-transferase, and lipid peroxides, were correlated with chronic value and survival endpoints of P. viridis after chronic exposure to Pb. Biochemical and histological responses to different concentrations of Pb were assessed and significant differences were observed between control and increasing exposure concentrations. Biomarker studies in internal organs confirmed that the observed changes are due to adverse effects of Pb. This assessment of toxicity was the first step to determining the seawater quality criteria for marine organisms.

Impacts of select organic ligands on the colloidal stability, dissolution dynamics, and toxicity of silver nanoparticles.

PubMed

Pokhrel, Lok R; Dubey, Brajesh; Scheuerman, Phillip R

2013-11-19

Key understanding of potential transformations that may occur on silver nanoparticle (AgNP) surface upon interaction with naturally ubiquitous organic ligands (e.g., -SH (thoil), humic acid, or -COO (carboxylate)) is limited. Herein we investigated how dissolved organic carbon (DOC), -SH (in cysteine, a well-known Ag(+) chelating agent), and -COO (in trolox, a well-known antioxidant) could alter the colloidal stability, dissolution rate, and toxicity of citrate-functionalized AgNPs (citrate-AgNPs) against a keystone crustacean Daphnia magna. Cysteine, DOC, or trolox amendment of citrate-AgNPs differentially modified particle size, surface properties (charge, plasmonic spectra), and ion release dynamics, thereby attenuating (with cysteine or trolox) or promoting (with DOC) AgNP toxicity. Except with DOC amendment, the combined toxicity of AgNPs and released Ag under cysteine or trolox amendment was lower than of AgNO3 alone. The results of this study show that citrate-AgNP toxicity can be associated with oxidative stress, ion release, and the organism biology. Our evidence suggests that specific organic ligands available in the receiving waters can differentially surface modify AgNPs and alter their environmental persistence (changing dissolution dynamics) and subsequently the toxicity; hence, we caveat to generalize that surface modified nanoparticles upon environmental release may not be toxic to receptor organisms.

Aquatic Toxicity Information Retrieval Data Base (ACQUIRE). Data file

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

The purpose of Acquire is to provide scientists and managers quick access to a comprehensive, systematic, computerized compilation of aquatic toxicity data. Scientific papers published both nationally and internationally on the toxicity of chemicals to aquatic organisms and plants are collected and reviewed for ACQUIRE. Independently compiled data files that meet ACQUIRE parameter and quality assurance criteria are also included. Selected toxicity test results and related testing information for any individual chemical from laboratory and field aquatic toxicity effects are included for tests with freshwater and marine organisms. The total number of data records in ACQUIRE is now over 105,300.more » This includes data from 6000 references, for 5200 chemicals and 2400 test species. A major data file, Acute Toxicity of Organic Chemicals (ATOC), has been incorporated into ACQUIRE. The ATOC file contains laboratory acute test data on 525 organic chemicals using juvenile fathead minnows.« less

Deriving Sediment Interstitial Water Remediation Goals ...

EPA Pesticide Factsheets

This document contains a methodology for developing interstitial water remediation goals (IWRGs) for nonionic organic pollutants (toxicants) in sediments for the protection of benthic organisms. The document provides the basis for using the final chronic values (FCVs) from EPA’s aquatic water quality criteria (AWQC) for the protection of aquatic life to set the IWRGs for toxicants in sediments. Concentrations of the toxicants in the sediment interstitial water are measured using passive sampling. This document also discusses how to evaluate the consistency between passive sampling measurements and sediment toxicity test results. When these data are consistent, one can be reasonably assured that the causes of toxicity to benthic organisms in the sediment have been correctly identified and that the developed IWRGs for the toxicants will be protective of the benthic organisms at the site. The consistency evaluation is an important step in developing defensible IWRGs. To assist in developing defensible IWRGs.

Silver nanocrystallites: Facile biofabrication using Shewanella oneidensis, and an evaluation of their comparative toxicity on Gram-negative and Gram-positive bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suresh, Anil K; Wang, Wei; Pelletier, Dale A

Microorganisms have long been known to develop resistance to metal ions either by sequestering metals inside the cell or by effluxing them into the extracellular media. Here we report the biosynthesis of extracellular silver based single nanocrystallites of well-defined composition and homogeneous morphology utilizing the -proteobacterium, Shewanella oneidensis strain MR-1, upon incubation with an aqueous solution of silver nitrate. Further characterization of these particles revealed that the crystals consist of small, reasonably monodispersed spheres in the size range 2 11 nm (with an average of 4 1.5 nm). The bactericidal effect of these biologically synthesized silver nanoparticles (biogenic-Ag) are comparedmore » to similar chemically synthesized nanoparticles (colloidal silver [colloidal-Ag] and oleate capped silver [oleate-Ag]). The determination of the bactericidal effect of these different silver nanoparticles was assessed using both Gram-negative (E. coli) and Gram-positive (B. subtilis) bacteria and based on the diameter of the inhibition zone in disc diffusion tests, minimum inhibitory concentrations, Live/Dead staining assays, and atomic force microscopy. From a toxicity perspective, a clear synthesis procedure, and a surface coat- and strain-dependent inhibition were observed for silver nanoparticles. Biogenic-Ag was found to be of higher toxicity when compared to colloidal-Ag for both E. coli and B. subtilis. E. coli was found to be more resistant to either of these nanoparticles than B. subtilis. In contrast, Oleate-Ag was not toxic to either of the bacteria. These findings have important implications for the potential uses of Ag nanomaterials and for their fate in biological and environmental systems.« less

Stage-dependency of apoptosis and the blood-testis barrier in the dogfish shark (Squalus acanthias): cadmium-induced changes as assessed by vital fluorescence techniques.

PubMed

McClusky, Leon M

2006-09-01

Naturally occurring heavy metals and synthetic compounds are potentially harmful for testicular function but evidence linking heavy metal exposure to reduced semen parameters is inconclusive. Elucidation of the exact stage at which the toxicant interferes with spermatogenesis is difficult because the various germ cell stages may have different sensitivities to any given toxicant, germ cell development is influenced by supporting testicular somatic cells and the presence of inter-Sertoli cell tight junctions create a blood-testis barrier, sequestering meiotic and postmeiotic germ cells in a special microenvironment. Sharks such as Squalus acanthias provide a suitable model for studying aspects of vertebrate spermatogenosis because of their unique features: spermatogenesis takes place within spermatocysts and relies mainly on Sertoli cells for somatic cell support; spermatocysts are linearly arranged in a maturational order across the diameter of the elongated testis; spermatocysts containing germ cells at different stages of development are topographically separated, resulting in visible zonation in testicular cross sections. We have used the vital dye acridine orange and a novel fluorescence staining technique to study this model to determine (1) the efficacy of these methods in assays of apoptosis and blood-testis barrier function, (2) the sensitivity of the various spermatogonial generations in Squalus to cadmium (as an illustrative spermatotoxicant) and (3) the way that cadmium might affect more mature spermatogenic stages and other physiological processes in the testis. Our results show that cadmium targets early spermatogenic stages, where it specifically activates a cell death program in susceptible (mature) spermatogonial clones, and negatively affects blood-testis barrier function. Since other parameters are relatively unaffected by cadmium, the effects of this toxicant on apoptosis are presumably process-specific and not attributable to general toxicity.

Phytoremediation of Ionic and Methyl Mercury Pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of humanmore » and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems.« less

Vesicular Monoamine Transporter 2 (VMAT2) Level Regulates MPTP Vulnerability and Clearance of Excess Dopamine in Mouse Striatal Terminals.

PubMed

Lohr, Kelly M; Chen, Merry; Hoffman, Carlie A; McDaniel, Miranda J; Stout, Kristen A; Dunn, Amy R; Wang, Minzheng; Bernstein, Alison I; Miller, Gary W

2016-09-01

The vesicular monoamine transporter 2 (VMAT2) packages neurotransmitters for release during neurotransmission and sequesters toxicants into vesicles to prevent neuronal damage. In mice, low VMAT2 levels causes catecholaminergic cell loss and behaviors resembling Parkinson's disease, while high levels of VMAT2 increase dopamine release and protect against dopaminergic toxicants. However, comparisons across these VMAT2 mouse genotypes were impossible due to the differing genetic background strains of the animals. Following back-crossing to a C57BL/6 line, we confirmed that mice with approximately 95% lower VMAT2 levels compared with wild-type (VMAT2-LO) display significantly reduced vesicular uptake, progressive dopaminergic terminal loss with aging, and exacerbated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity. Conversely, VMAT2-overexpressing mice (VMAT2-HI) are protected from the loss of striatal terminals following MPTP treatment. We also provide evidence that enhanced vesicular filling in the VMAT2-HI mice modifies the handling of newly synthesized dopamine, indicated by changes in indirect measures of extracellular dopamine clearance. These results confirm the role of VMAT2 in the protection of vulnerable nigrostriatal dopamine neurons and may also provide new insight into the side effects of L-DOPA treatments in Parkinson's disease. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Photo-enhanced toxicity of fluoranthene to Gulf of Mexico marine organisms at different larval ages and ultraviolet light intensities.

PubMed

Finch, Bryson E; Stubblefield, William A

2016-05-01

Significant increases in toxicity have been observed as a result of polycyclic aromatic hydrocarbon (PAH) absorption of ultraviolet (UV) radiation in aquatic organisms. Early life stage aquatic organisms are predicted to be more susceptible to PAH photo-enhanced toxicity as a result of their translucence and tendency to inhabit shallow littoral or surface waters. The objective of the present study was to evaluate the sensitivity of varying ages of larval mysid shrimp (Americamysis bahia), inland silverside (Menidia beryllina), sheepshead minnow (Cyprinodon variegatus), and Gulf killifish (Fundulus grandis) to photo-enhanced toxicity and to examine the correlation between photo-enhanced toxicity and organism pigmentation. Organisms were exposed to fluoranthene and artificial UV light at different larval ages and results were compared using median lethal concentrations (LC50s) and the lethal time-to-death (LT50s). In addition, a high UV light intensity, short-duration (4-h) experiment was conducted at approximately 24 W/m(2) of ultraviolet radiation A (UV-A) and compared with a low-intensity, long-duration (12-h) experiment at approximately 8 W/m(2) of UV-A. The results indicated decreased toxicity with increasing age for all larval organisms. The amount of organism pigmentation was correlated with observed LC50 and LT50 values. High-intensity short-duration exposure resulted in greater toxicity than low-intensity long-duration UV treatments for mysid shrimp, inland silverside, and sheepshead minnow. Data from these experiments suggest that toxicity is dependent on age, pigmentation, UV light intensity, and fluoranthene concentration. © 2015 SETAC.

Bacterial toxicity assessment of drinking water treatment residue (DWTR) and lake sediment amended with DWTR.

PubMed

Yuan, Nannan; Wang, Changhui; Pei, Yuansheng

2016-11-01

Drinking water treatment residue (DWTR) seems to be very promising for controlling lake sediment pollution. Logically, acquisition of the potential toxicity of DWTR will be beneficial for its applications. In this study, the toxicity of DWTR and sediments amended with DWTR to Aliivibrio fischeri was evaluated based on the Microtox(®) solid and leachate phase assays, in combination with flow cytometry analyses and the kinetic luminescent bacteria test. The results showed that both solid particles and aqueous/organic extracts of DWTR exhibited no toxicity to the bacterial luminescence and growth. The solid particles of DWTR even promoted bacterial luminescence, possibly because DWTR particles could act as a microbial carrier and provide nutrients for bacteria growth. Bacterial toxicity (either luminescence or growth) was observed from the solid phase and aqueous/organic extracts of sediments with or without DWTR addition. Further analysis showed that the solid phase toxicity was determined to be related mainly to the fixation of bacteria to fine particles and/or organic matter, and all of the observed inhibition resulting from aqueous/organic extracts was identified as non-significant. Moreover, DWTR addition not only had no adverse effect on the aqueous/organic extract toxicity of the sediment but also reduced the solid phase toxicity of the sediment. Overall, in practical application, the solid particles, the water-soluble substances transferred to surface water or the organic substances in DWTR had no toxicity or any delayed effect on bacteria in lakes, and DWTR can therefore be considered as a non-hazardous material. Copyright © 2016 Elsevier Ltd. All rights reserved.

Estimating aquatic toxicity as determined through laboratory tests of great lakes sediments containing complex mixtures of environmental contaminants

USGS Publications Warehouse

1996-01-01

We developed and evaluated a total toxic units modeling approach for predicting mean toxicity as measured in laboratory tests for Great Lakes sediments containing complex mixtures of environmental contaminants (e.g., polychlorinated biphenyls, polycyclic aromatic hydrocarbons, pesticides, chlorinated dioxins, and metals). The approach incorporates equilibrium partitioning and organic carbon control of bioavailability for organic contaminants and acid volatile sulfide (AVS) control for metals, and includes toxic equivalency for planar organic chemicals. A toxic unit is defined as the ratio of the estimated pore-water concentration of a contaminant to the chronic toxicity of that contaminant, as estimated by U.S. Environmental Protection Agency Ambient Water Quality Criteria (AWQC). The toxic unit models we developed assume complete additivity of contaminant effects, are completely mechanistic in form, and were evaluated without any a posteriori modification of either the models or the data from which the models were developed and against which they were tested. A linear relationship between total toxic units, which included toxicity attributable to both iron and un-ionized ammonia, accounted for about 88% of observed variability in mean toxicity; a quadratic relationship accounted for almost 94%. Exclusion of either bioavailability components (i.e., equilibrium partitioning control of organic contaminants and AVS control of metals) or iron from the model substantially decreased its ability to predict mean toxicity. A model based solely on un-ionized ammonia accounted for about 47% of the variability in mean toxicity. We found the toxic unit approach to be a viable method for assessing and ranking the relative potential toxicity of contaminated sediments.

Cadmium accumulation and protein binding patterns in tissues of the rainbow trout, Salmo gairdneri.

PubMed Central

Kay, J; Thomas, D G; Brown, M W; Cryer, A; Shurben, D; Solbe, J F; Garvey, J S

1986-01-01

Rainbow trout were exposed to defined levels of cadmium in their aquarium water for differing periods at a variety of near-lethal concentrations that ensured the survival of the majority of the fish. The gills, liver and kidney together accounted for 99% of the accumulated load of body cadmium in the fish under these conditions. Although the proportion of total cadmium present in the liver remained relatively constant throughout, the distribution of the remainder between gill and kidney altered with the time of exposure. The cadmium in all three organs was bound by two low molecular weight proteins distinct in character from metallothionein. The isoforms of metallothionein were also present but were found to bind only zinc and copper. By contrast, when trout were injected with cadmium intraperitoneally, most of the metal accumulated in the liver where it was sequestered by the two isoforms of metallothionein. Pre-exposure of the trout to either a low concentration of cadmium (for several months) or to an elevated concentration of zinc (for 5 days) allowed the animals to survive a subsequent exposure to a high, otherwise lethal concentration of cadmium. The proteins responsible for sequestration of the two metals were identified, but two different mechanisms seemed to be involved in the protection of the animals. The significance of these observations in terms of the induction of proteins and the prevention of the toxic effects of cadmium is considered. PMID:3709433

Raf Kinase Inhibitory Protein protects cells against locostatin-mediated inhibition of migration.

PubMed

Shemon, Anne N; Eves, Eva M; Clark, Matthew C; Heil, Gary; Granovsky, Alexey; Zeng, Lingchun; Imamoto, Akira; Koide, Shohei; Rosner, Marsha Rich

2009-06-24

Raf Kinase Inhibitory Protein (RKIP, also PEBP1), a member of the Phosphatidylethanolamine Binding Protein family, negatively regulates growth factor signaling by the Raf/MAP kinase pathway. Since an organic compound, locostatin, was reported to bind RKIP and inhibit cell migration by a Raf-dependent mechanism, we addressed the role of RKIP in locostatin function. We analyzed locostatin interaction with RKIP and examined the biological consequences of locostatin binding on RKIP function. NMR studies show that a locostatin precursor binds to the conserved phosphatidylethanolamine binding pocket of RKIP. However, drug binding to the pocket does not prevent RKIP association with its inhibitory target, Raf-1, nor affect RKIP phosphorylation by Protein Kinase C at a regulatory site. Similarly, exposure of wild type, RKIP-depleted HeLa cells or RKIP-deficient (RKIP(-/-)) mouse embryonic fibroblasts (MEFs) to locostatin has no effect on MAP kinase activation. Locostatin treatment of wild type MEFs causes inhibition of cell migration following wounding. RKIP deficiency impairs migration further, indicating that RKIP protects cells against locostatin-mediated inhibition of migration. Locostatin treatment of depleted or RKIP(-/-) MEFs reveals cytoskeletal disruption and microtubule abnormalities in the spindle. These results suggest that locostatin's effects on cytoskeletal structure and migration are caused through mechanisms independent of its binding to RKIP and Raf/MAP kinase signaling. The protective effect of RKIP against drug inhibition of migration suggests a new role for RKIP in potentially sequestering toxic compounds that may have deleterious effects on cells.

THE INFLUENCE OF ORGANIC MATTER QUALITY ON THE TOXICITY AND PARTIONING OF SEDIMENT-ASSOCIATED FLUORANTHENE

EPA Science Inventory

Organic matter in sediment is derived from many sources, including dead plants and animals, fecal matter, and flocculated colloidal organic matter. hemical partitioning and toxicity of nonpolar organic contaminants is strongly affected by the quantity of sediment organic matter. ...

Bioavailability of biologically sequestered cadmium and the implications of metal detoxification

USGS Publications Warehouse

Wallace, W.G.; Lopez, G.R.

1997-01-01

The deposit-feeding oligochaete Limnodrilus hoffmeisteri possesses metallothionein-like proteins and metal-rich granules for storing and detoxifying cadmium (Cd). In this study we investigated the bioavailability of Cd sequestered within this oligochaete by conducting feeding experiments with 109Cd-labeled oligochaetes and the omnivorous grass shrimp Palaemonetes pugio. We also make predictions on Cd trophic transfer based on oligochaete subcellular Cd distributions and absorption efficiencies of Cd by shrimp Cytosol [including metallothionein-like proteins and other proteins) and a debris fraction (including metal-rich granules and tissue fragments) isolated from homogenized 109Cd-labeled oligochaetes were embedded in gelatin and fed to shrimp. The 109Cd absorption efficiencies of shrimp fed these subcellular fractions were 84.8 and 48.6%, respectively, and were significantly different (p < 0.001), indicating that 109Cd bound in these fractions was not equally available to a predator. Mass balance equations demonstrate that shrimp fed whole worms absorb 61.5% of the ingested 109Cd, an absorption efficiency similar to that obtained experimentally (57.1%). Furthermore, the majority of the absorbed 109Cd comes from the fraction containing metallothionein-like proteins (i.e. cytosol). 109Cd absorbed from the debris fraction probably comes from the digestion of tissue fragments, rather than metal-rich granules. The ecological significance of these findings is that prey detoxification mechanisms may mediate the bioreduction or bioaccumulation of toxic metals along fond chains by altering metal bioavailability. Another important finding is that trophic transfer of metal can be predicted based on the subcellular metal distribution of prey.

Comparative Investigation of Copper Tolerance and Identification of Putative Tolerance Related Genes in Tardigrades

PubMed Central

Hygum, Thomas L.; Fobian, Dannie; Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Grosell, Martin; Møbjerg, Nadja

2017-01-01

Tardigrades are microscopic aquatic animals renowned for their tolerance toward extreme environmental conditions. The current study is the first to investigate their tolerance toward heavy metals and we present a novel tardigrade toxicant tolerance assay based on activity assessments as a measure of survival. Specifically, we compare tolerance toward copper in four species representing different evolutionary lineages, habitats and adaptation strategies, i.e., a marine heterotardigrade, Echiniscoides sigismundi, a limno-terrestrial heterotardigrade, Echiniscus testudo, a limno-terrestrial eutardigrade, Ramazzottius oberhaeuseri, and a marine eutardigrade, Halobiotus crispae. The latter was sampled at a time of year, when the population is predominantly represented by aberrant P1 cysts, while the other species were in normal active states prior to exposure. Based on volume measurements and a general relation between body mass and copper tolerance, expected tardigrade EC50 values were estimated at 0.5–2 μg l−1. Following 24 h of exposure, tolerance was high with no apparent link to lineage or habitat. EC50s (95% CI), 24 h after exposure, were estimated at 178 (168–186) and 310 (295–328) μg l−1, respectively, for E. sigismundi and R. oberhaeuseri, whereas E. testudo and H. crispae were less affected. Highest tolerance was observed in H. crispae with a mean ± s.e.m. activity of 77 ± 2% (n = 3) 24 h after removal from ~3 mg l−1 copper, suggesting that tardigrade cysts have increased tolerance toward toxicants. In order to identify putative tolerance related genes, an E. sigismundi transcriptome was searched for key enzymes involved in osmoregulation, antioxidant defense and copper metabolism. We found high expression of Na/K ATPase and carbonic anhydrase, known targets for copper. Our transcriptome, furthermore, revealed high expression of antioxidant enzymes, copper transporters, ATOX1, and a Cu-ATPase. In summary, our results indicate that tardigrades express well-known key osmoregulatory enzymes, supporting the hypothesis that copper inhibits sodium turnover as demonstrated for other aquatic organisms. Tardigrades, nevertheless, have high tolerance toward the toxicant, which is likely linked to high expression of antioxidant enzymes and an ability to enter dormant states. Tardigrades, furthermore, seem to have a well-developed battery of cuproproteins involved in copper homeostasis, providing basis for active copper sequestering and excretion. PMID:28293195

Comparative Investigation of Copper Tolerance and Identification of Putative Tolerance Related Genes in Tardigrades.

PubMed

Hygum, Thomas L; Fobian, Dannie; Kamilari, Maria; Jørgensen, Aslak; Schiøtt, Morten; Grosell, Martin; Møbjerg, Nadja

2017-01-01

Tardigrades are microscopic aquatic animals renowned for their tolerance toward extreme environmental conditions. The current study is the first to investigate their tolerance toward heavy metals and we present a novel tardigrade toxicant tolerance assay based on activity assessments as a measure of survival. Specifically, we compare tolerance toward copper in four species representing different evolutionary lineages, habitats and adaptation strategies, i.e., a marine heterotardigrade, Echiniscoides sigismundi , a limno-terrestrial heterotardigrade, Echiniscus testudo , a limno-terrestrial eutardigrade, Ramazzottius oberhaeuseri , and a marine eutardigrade, Halobiotus crispae . The latter was sampled at a time of year, when the population is predominantly represented by aberrant P1 cysts, while the other species were in normal active states prior to exposure. Based on volume measurements and a general relation between body mass and copper tolerance, expected tardigrade EC50 values were estimated at 0.5-2 μg l -1 . Following 24 h of exposure, tolerance was high with no apparent link to lineage or habitat. EC50s (95% CI), 24 h after exposure, were estimated at 178 (168-186) and 310 (295-328) μg l -1 , respectively, for E. sigismundi and R. oberhaeuseri , whereas E. testudo and H. crispae were less affected. Highest tolerance was observed in H. crispae with a mean ± s.e.m . activity of 77 ± 2% ( n = 3) 24 h after removal from ~3 mg l -1 copper, suggesting that tardigrade cysts have increased tolerance toward toxicants. In order to identify putative tolerance related genes, an E. sigismundi transcriptome was searched for key enzymes involved in osmoregulation, antioxidant defense and copper metabolism. We found high expression of Na/K ATPase and carbonic anhydrase, known targets for copper. Our transcriptome, furthermore, revealed high expression of antioxidant enzymes, copper transporters, ATOX1, and a Cu-ATPase. In summary, our results indicate that tardigrades express well-known key osmoregulatory enzymes, supporting the hypothesis that copper inhibits sodium turnover as demonstrated for other aquatic organisms. Tardigrades, nevertheless, have high tolerance toward the toxicant, which is likely linked to high expression of antioxidant enzymes and an ability to enter dormant states. Tardigrades, furthermore, seem to have a well-developed battery of cuproproteins involved in copper homeostasis, providing basis for active copper sequestering and excretion.

FROM ORGANISMS TO POPULATIONS: MODELING AQUATIC TOXICITY DATA ACROSS TWO LEVELS OF BIOLOGICAL ORGANIZATION.

EPA Science Inventory

A critical step in estimating the ecological effects of a toxicant is extrapolating organism-level response data across higher levels of biological organization. In the present study, the organism-to-population link is made for the mysid, Americamysis bahia, exposed to a range of...

Phytoremediation of Ionic and Methyl Mercury Pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meagher, Richard B.

Phytoremediation is defined as the use of plants to extract, resist, detoxify, and/or sequester toxic environmental pollutants. The long-term goal of the proposed research is to develop and test highly productive, field-adapted plant species that have been engineered for the phytoremediation of mercury. A variety of different genes, which should enable plants to clean mercury polluted sites are being tested as tools for mercury phytoremediation, first in model laboratory plants and then in potential field species. Several of these genes have already been shown to enhance mercury phytoremediation. Mercury pollution is a serious, world-wide problem affecting the health of humanmore » and wildlife populations. Environmentally, the most serious mercury threat is the production of methylmercury (CH3Hg+) by native bacteria at mercury contaminated wetland sites. Methylmercury is inherently more toxic than metallic (Hg(0)) or ionic (Hg(II)) mercury, and because methylmercury is prolifically biomagnified up the food chain, it poses the most immediate danger to animal populations. We have successfully engineered two model plants, Arabidopsis and tobacco, to use the bacterial merB gene to convert methylmercury to less toxic ionic mercury and to use the bacterial merA gene to further detoxify ionic mercury to the least toxic form of mercury, metallic mercury. Plants expressing both MerA and MerB proteins detoxify methylmercury in two steps to the metallic form. These plants germinate, grow, and set seed at normal growth rates on levels of methylmercury or ionic mercury that are lethal to normal plants. Our newest efforts involve engineering plants with several additional bacterial and plant genes that allow for higher levels of mercury resistance and mercury hyperaccumulation. The potential for these plants to hyperaccumulate mercury was further advanced by developing constitutive, aboveground, and root-specific gene expression systems. Our current strategy is to engineer plants to control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant.« less

Influence of flow-through and renewal exposures on the toxicity of copper to rainbow trout

USGS Publications Warehouse

Welsh, P.G.; Lipton, J.; Mebane, C.A.; Marr, J.C.A.

2008-01-01

We examined changes in water chemistry and copper (Cu) toxicity in three paired renewal and flow-through acute bioassays with rainbow trout (Oncorhynchus mykiss). Test exposure methodology influenced both exposure water chemistry and measured Cu toxicity. Ammonia and organic carbon concentrations were higher and the fraction of dissolved Cu lower in renewal tests than in paired flow-through tests. Cu toxicity was also lower in renewal tests; 96 h dissolved Cu LC50 values were 7-60% higher than LC50s from matching flow-through tests. LC50 values in both types of tests were related to dissolved organic carbon (DOC) concentrations in exposure tanks. Increases in organic carbon concentrations in renewal tests were associated with reduced Cu toxicity, likely as a result of the lower bioavailability of Cu-organic carbon complexes. The biotic ligand model of acute Cu toxicity tended to underpredict toxicity in the presence of DOC. Model fits between predicted and observed toxicity were improved by assuming that only 50% of the measured DOC was reactive, and that this reactive fraction was present as fulvic acid. ?? 2007 Elsevier Inc. All rights reserved.

PCR detection of groundwater bacteria associated with colloidal transport

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cruz-Perez, P.; Stetzenbach, L.D.; Alvarez, A.J.

1996-02-29

Colloidal transport may increase the amount of contaminant material than that which could be transported by water flow alone. The role of colloids in groundwater contaminant transport is complicated and may involve many different processes, including sorption of elements onto colloidal particles, coagulation/dissolution, adsorption onto solid surfaces, filtration, and migration. Bacteria are known to concentrate minerals and influence the transport of compounds in aqueous environments and may also serve as organic colloids, thereby influencing subsurface transport of radionuclides and other contaminants. The initial phase of the project consisted of assembling a list of bacteria capable of sequestering or facilitating mineralmore » transport. The development and optimization of the PCR amplification assay for the detection of the organisms of interest, and the examination of regional groundwaters for those organisms, are presented for subsequent research.« less

Development of biotic ligand models for chronic manganese toxicity to fish, invertebrates, and algae.

PubMed

Peters, Adam; Lofts, Stephen; Merrington, Graham; Brown, Bruce; Stubblefield, William; Harlow, Keven

2011-11-01

Ecotoxicity tests were performed with fish, invertebrates, and algae to investigate the effect of water quality parameters on Mn toxicity. Models were developed to describe the effects of Mn as a function of water quality. Calcium (Ca) has a protective effect on Mn toxicity for both fish and invertebrates, and magnesium (Mg) also provides a protective effect for invertebrates. Protons have a protective effect on Mn toxicity to algae. The models derived are consistent with models of the toxicity of other metals to aquatic organisms in that divalent cations can act as competitors to Mn toxicity in fish and invertebrates, and protons act as competitors to Mn toxicity in algae. The selected models are able to predict Mn toxicity to the test organisms to within a factor of 2 in most cases. Under low-pH conditions invertebrates are the most sensitive taxa, and under high-pH conditions algae are most sensitive. The point at which algae become more sensitive than invertebrates depends on the Ca concentration and occurs at higher pH when Ca concentrations are low, because of the sensitivity of invertebrates under these conditions. Dissolved organic carbon concentrations have very little effect on the toxicity of Mn to aquatic organisms. Copyright © 2011 SETAC.

Sediment Toxicity Identification Evaluations (TIEs): Manipulating Bioavailability to Whole Organisms to Identify Environmental Toxins

EPA Science Inventory

Toxicity tests are a common method for determining whether sediment contaminants represent an environmental risk. Toxicity tests indicate if contaminants in sediments are bioavailable and capable of causing adverse biological effects to whole aquatic organisms. Several environmen...

Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms.

EPA Science Inventory

The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) coated silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) in marine organisms via marine sediment exposure was investigated. Results from 7-d sediment toxicity tests indicate that Ag...

Toxicity of benzotriazole and benzotriazole derivatives to three aquatic species.

PubMed

Pillard, D A; Cornell, J S; Dufresne, D L; Hernandez, M T

2001-02-01

Benzotriazole and its derivatives comprise an important class of corrosion inhibitors, typically used as trace additives in industrial chemical mixtures such as coolants, deicers, surface coatings, cutting fluids, and hydraulic fluids. Recent studies have shown that benzotriazole derivatives are a major component of aircraft deicing fluids (ADFs) responsible for toxicity to bacteria (Microtox). Our current research compared the toxicity of benzotriazole (BT), two methylbenzotriazole (MeBT) isomers, and butylbenzotriazole (BBT). Acute toxicity assays were used to model the response of three common test organisms: Microtox bacteria (Vibrio fischeri), fathead minnow (Pimephales promelas) and water flea (Ceriodaphnia dubia). The response of all the three organisms varied over two orders of magnitude among all compounds. Vibrio fischeri was more sensitive than either C. dubia or P. promelas to all the test materials, while C. dubia was less sensitive than P. promelas. The response of test organisms to unmethylated benzotriazole and 4-methylbenzotriazole was similar, whereas 5-methylbenzotriazole was more toxic than either of these two compounds. BBT was the most toxic benzotriazole derivative tested, inducing acute toxicity at a concentration of < or = 3.3 mg/l to all organisms.

AQUIRE: Aquatic Toxicity Information Retrieval data base. Data file

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, E.; Pilli, A.

The purpose of Aquatic Toxicity Information Retrieval (AQUIRE) data base is to provide scientists and managers quick access to a comprehensive, systematic, computerized compilation of aquatic toxicity data. Scientific papers published both nationally and internationally on the toxicity of chemicals to aquatic organisms and plants are collected and reviewed for AQUIRE. Independently compiled data files that meet AQUIRE parameter and quality assurance criteria are also included. Selected toxicity-test results and related testing information for any individual chemical from laboratory and field aquatic toxicity tests are extracted and added to AQUIRE. Acute, sublethal, and bioconcentration effects are included for tests withmore » freshwater and marine organisms. The total number of data records in AQUIRE now equals 104,500. This includes data from 6000 references, for 5200 chemicals and 2400 test species. A major data file, Acute Toxicity of Organic Chemicals (ATOC), has been incorporated into AQUIRE. The ATOC file contains laboratory acute test data on 525 organic chemicals using juvenile fathead minnows. The complete data file can be accessed by requesting review code 5 as a search parameter.« less

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2014 CFR

2014-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2013 CFR

2013-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2012 CFR

2012-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...

40 CFR 268.38 - Waste specific prohibitions-newly identified organic toxicity characteristic wastes and newly...

Code of Federal Regulations, 2011 CFR

2011-07-01

... identified organic toxicity characteristic wastes and newly listed coke by-product and chlorotoluene... specific prohibitions—newly identified organic toxicity characteristic wastes and newly listed coke by... numbers F037, F038, K107-K112, K117, K118, K123-K126, K131, K132, K136, U328, U353, U359, and soil and...

Chemical evolution of atmospheric organic carbon over multiple generations of oxidation

NASA Astrophysics Data System (ADS)

Isaacman-VanWertz, Gabriel; Massoli, Paola; O'Brien, Rachel; Lim, Christopher; Franklin, Jonathan P.; Moss, Joshua A.; Hunter, James F.; Nowak, John B.; Canagaratna, Manjula R.; Misztal, Pawel K.; Arata, Caleb; Roscioli, Joseph R.; Herndon, Scott T.; Onasch, Timothy B.; Lambe, Andrew T.; Jayne, John T.; Su, Luping; Knopf, Daniel A.; Goldstein, Allen H.; Worsnop, Douglas R.; Kroll, Jesse H.

2018-02-01

The evolution of atmospheric organic carbon as it undergoes oxidation has a controlling influence on concentrations of key atmospheric species, including particulate matter, ozone and oxidants. However, full characterization of organic carbon over hours to days of atmospheric processing has been stymied by its extreme chemical complexity. Here we study the multigenerational oxidation of α-pinene in the laboratory, characterizing products with several state-of-the-art analytical techniques. Although quantification of some early generation products remains elusive, full carbon closure is achieved (within measurement uncertainty) by the end of the experiments. These results provide new insights into the effects of oxidation on organic carbon properties (volatility, oxidation state and reactivity) and the atmospheric lifecycle of organic carbon. Following an initial period characterized by functionalization reactions and particle growth, fragmentation reactions dominate, forming smaller species. After approximately one day of atmospheric aging, most carbon is sequestered in two long-lived reservoirs—volatile oxidized gases and low-volatility particulate matter.

Chemical evolution of atmospheric organic carbon over multiple generations of oxidation.

PubMed

Isaacman-VanWertz, Gabriel; Massoli, Paola; O'Brien, Rachel; Lim, Christopher; Franklin, Jonathan P; Moss, Joshua A; Hunter, James F; Nowak, John B; Canagaratna, Manjula R; Misztal, Pawel K; Arata, Caleb; Roscioli, Joseph R; Herndon, Scott T; Onasch, Timothy B; Lambe, Andrew T; Jayne, John T; Su, Luping; Knopf, Daniel A; Goldstein, Allen H; Worsnop, Douglas R; Kroll, Jesse H

2018-04-01

The evolution of atmospheric organic carbon as it undergoes oxidation has a controlling influence on concentrations of key atmospheric species, including particulate matter, ozone and oxidants. However, full characterization of organic carbon over hours to days of atmospheric processing has been stymied by its extreme chemical complexity. Here we study the multigenerational oxidation of α-pinene in the laboratory, characterizing products with several state-of-the-art analytical techniques. Although quantification of some early generation products remains elusive, full carbon closure is achieved (within measurement uncertainty) by the end of the experiments. These results provide new insights into the effects of oxidation on organic carbon properties (volatility, oxidation state and reactivity) and the atmospheric lifecycle of organic carbon. Following an initial period characterized by functionalization reactions and particle growth, fragmentation reactions dominate, forming smaller species. After approximately one day of atmospheric aging, most carbon is sequestered in two long-lived reservoirs-volatile oxidized gases and low-volatility particulate matter.

Dissolved Solids as HD Bioeffluent Toxicants.

DTIC Science & Technology

1998-12-01

12 The question still remains about whether the toxicity of the SBR effluent was caused by either the animals’ inability to osmoregulate in a high...the dissolved solids. The inability of freshwater organisms to osmoregulate in such high saline environments caused toxicity. Freshwater organisms are

Biotic ligand modeling approach: Synthesis of the effect of major cations on the toxicity of metals to soil and aquatic organisms.

PubMed

Ardestani, Masoud M; van Straalen, Nico M; van Gestel, Cornelis A M

2015-10-01

The biotic ligand model (BLM) approach is used to assess metal toxicity, taking into account the competition of other cations with the free metal ions for binding to the biotic ligand sites of aquatic and soil organisms. The bioavailable fraction of metals, represented by the free metal ion, is a better measure than the total concentration for assessing their potential risk to the environment. Because BLMs are relating toxicity to the fraction of biotic ligands occupied by the metal, they can be useful for investigating factors affecting metal bioaccumulation and toxicity. In the present review, the effects of major cations on the toxicity of metals to soil and aquatic organisms were comprehensively studied by performing a meta-analysis of BLM literature data. Interactions at the binding sites were shown to be species- and metal-specific. The main factors affecting the relationships between toxicity and conditional binding constants for metal binding at the biotic ligand appeared to be Ca(2+) , Mg(2+) , and protons. Other important characteristics of the exposure medium, such as levels of dissolved organic carbon and concentrations of other cations, should also be considered to obtain a proper assessment of metal toxicity to soil and aquatic organisms. © 2015 SETAC.

Sustainable Algal Energy Production and Environmental Remediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooke, William E.

2012-07-14

Overall, our results confirm that wild algal species sequester a wide range of organic and metal contaminants and excess nutrients (PAHs, trace metals, and nutrients) from natural waters, and suggest parameters that could be useful in predicting uptake rates for algae growing on an algal floway or other algal growth systems in the environment or in industrial processes. The implication for various fuel production processes differ with the detailed unit operations involved, and these results will be of use in the developing of scaling experiments for various types of engineering process designs.

Elution of Uranium and Transition Metals from Amidoxime-Based Polymer Adsorbents for Sequestering Uranium from Seawater

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pan, Horng-Bin; Kuo, Li-Jung; Wai, Chien M.

2015-11-30

High-surface-area amidoxime and carboxylic acid grafted polymer adsorbents developed at Oak Ridge National Laboratory were tested for sequestering uranium in a flowing seawater flume system at the PNNL-Marine Sciences Laboratory. FTIR spectra indicate that a KOH conditioning process is necessary to remove the proton from the carboxylic acid and make the sorbent effective for sequestering uranium from seawater. The alkaline conditioning process also converts the amidoxime groups to carboxylate groups in the adsorbent. Both Na 2CO 3-H 2O 2 and hydrochloric acid elution methods can remove ~95% of the uranium sequestered by the adsorbent after 42 days of exposure inmore » real seawater. The Na 2CO 3-H 2O 2 elution method is more selective for uranium than conventional acid elution. Iron and vanadium are the two major transition metals competing with uranium for adsorption to the amidoxime-based adsorbents in real seawater.« less

75 FR 70276 - Statement of Organization, Functions, and Delegations of Authority

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

... of Organization, Functions, and Delegations of Authority Part J (Agency for Toxic Substances and Disease Registry) of the Statement of Organization, Functions, and Delegations of Authority of the... Toxic Substances and Disease Registry. Section J-B, Organization and Functions, is hereby amended as...

A review of the mechanism of injury and treatment approaches for illness resulting from exposure to water-damaged buildings, mold, and mycotoxins.

PubMed

Hope, Janette

2013-01-01

Physicians are increasingly being asked to diagnose and treat people made ill by exposure to water-damaged environments, mold, and mycotoxins. In addition to avoidance of further exposure to these environments and to items contaminated by these environments, a number of approaches have been used to help persons affected by exposure to restore their health. Illness results from a combination of factors present in water-damaged indoor environments including, mold spores and hyphal fragments, mycotoxins, bacteria, bacterial endotoxins, and cell wall components as well as other factors. Mechanisms of illness include inflammation, oxidative stress, toxicity, infection, allergy, and irritant effects of exposure. This paper reviews the scientific literature as it relates to commonly used treatments such as glutathione, antioxidants, antifungals, and sequestering agents such as cholestyramine, charcoal, clay and chlorella, antioxidants, probiotics, and induced sweating.

A Review of the Mechanism of Injury and Treatment Approaches for Illness Resulting from Exposure to Water-Damaged Buildings, Mold, and Mycotoxins

PubMed Central

2013-01-01

Physicians are increasingly being asked to diagnose and treat people made ill by exposure to water-damaged environments, mold, and mycotoxins. In addition to avoidance of further exposure to these environments and to items contaminated by these environments, a number of approaches have been used to help persons affected by exposure to restore their health. Illness results from a combination of factors present in water-damaged indoor environments including, mold spores and hyphal fragments, mycotoxins, bacteria, bacterial endotoxins, and cell wall components as well as other factors. Mechanisms of illness include inflammation, oxidative stress, toxicity, infection, allergy, and irritant effects of exposure. This paper reviews the scientific literature as it relates to commonly used treatments such as glutathione, antioxidants, antifungals, and sequestering agents such as Cholestyramine, charcoal, clay and chlorella, antioxidants, probiotics, and induced sweating. PMID:23710148

Metal binding proteins, recombinant host cells and methods

DOEpatents

Summers, Anne O.; Caguiat, Jonathan J.

2004-06-15

The present disclosure provides artificial heavy metal binding proteins termed chelons by the inventors. These chelons bind cadmium and/or mercuric ions with relatively high affinity. Also disclosed are coding sequences, recombinant DNA molecules and recombinant host cells comprising those recombinant DNA molecules for expression of the chelon proteins. In the recombinant host cells or transgenic plants, the chelons can be used to bind heavy metals taken up from contaminated soil, groundwater or irrigation water and to concentrate and sequester those ions. Recombinant enteric bacteria can be used within the gastrointestinal tracts of animals or humans exposed to toxic metal ions such as mercury and/or cadmium, where the chelon recombinantly expressed in chosen in accordance with the ion to be rededicated. Alternatively, the chelons can be immobilized to solid supports to bind and concentrate heavy metals from a contaminated aqueous medium including biological fluids.

The Influence of Soil Characteristics on the Toxicity of Oil Refinery Waste for the Springtail Folsomia candida (Collembola).

PubMed

Reinecke, Adriaan J; van Wyk, Mia; Reinecke, Sophie A

2016-06-01

We determined the toxicity of oil refinery waste in three soils using the springtail Folsomia candida (Collembola) in bioassays. Sublethal exposure to a concentration series of API-sludge presented EC50's for reproduction of 210 mg/kg in site soil; 880 mg/kg in LUFA2.2- and 3260 mg/kg in OECD-soil. The sludge was the least toxic in the OECD-soil with the highest clay and organic matter content, the highest maximum water holding capacity, and the least amount of sand. It was the most toxic in the reference site soil with the lowest organic matter content and highest sand content. The results emphasized the important role of soil characteristics such as texture and organic matter content in influencing toxicity, possibly by affecting bioavailability of toxicants.

Native Soil Charcoal as a Model for Designing Biochar for Carbon Sequestration

EPA Science Inventory

Under changing climate a variety of mechanisms for removing carbon from the atmosphere and sequestering it elsewhere are being considered to reduce the forcing of the atmosphere. Amending soils with biochar has been proposed as one long-term means of sequestering carbon originat...

Sediment toxicity identification evaluation (TIE) studies at marine sites suspected of ordnance contamination

USGS Publications Warehouse

Carr, R.S.; Nipper, M.; Biedenbach, J.M.; Hooten, R.L.; Miller, K.; Saepoff, S.

2001-01-01

A sediment quality assessment survey and subsequent toxicity identification evaluation (TIE) study was conducted at several sites in Puget Sound, Washington. The sites were previously suspected of contamination with ordnance compounds. The initial survey employed sea urchin porewater toxicity tests to locate the most toxic stations. Sediments from the most toxic stations were selected for comprehensive chemical analyses. Based on the combined information from the toxicity and chemical data, three adjacent stations in Ostrich Bay were selected for the TIE study. The results of the phase I TIE suggested that organics and metals were primarily responsible for the observed toxicity in the sea urchin fertilization test. In addition to these contaminants, ammonia was also contributing to the toxicity for the sea urchin embryological development test. The phase II TIE study isolated the majority of the toxicity in the fraction containing nonpolar organics with high log Kow, but chemical analyses failed to identify a compound present at a concentration high enough to be responsible for the observed toxicity. The data suggest that some organic or organometallic contaminant(s) that were not included in the comprehensive suite of chemical analyses caused the observed toxicological responses.

Residual organic matter and microbial respiration in bottom ash: Effects on metal leaching and eco-toxicity.

PubMed

Ilyas, A; Persson, K M; Persson, M

2015-09-01

A common assumption regarding the residual organic matter, in bottom ash, is that it does not represent a significant pool of organic carbon and, beyond metal-ion complexation process, it is of little consequence to evolution of ash/leachate chemistry. This article evaluates the effect of residual organic matter and associated microbial respiratory processes on leaching of toxic metals (i.e. arsenic, copper, chromium, molybdenum, nickel, lead, antimony and zinc), eco-toxicity of ash leachates. Microbial respiration was quantified with help of a respirometric test equipment OXITOP control system. The effect of microbial respiration on metal/residual organic matter leaching and eco-toxicity was quantified with the help of batch leaching tests and an eco-toxicity assay - Daphnia magna. In general, the microbial respiration process decreased the leachate pH and eco-toxicity, indicating modification of bioavailability of metal species. Furthermore, the leaching of critical metals, such as copper and chromium, decreased after the respiration in both ash types (fresh and weathered). It was concluded that microbial respiration, if harnessed properly, could enhance the stability of fresh bottom ash and may promote its reuse. © The Author(s) 2015.

EMISSIONS OF ORGANIC AIR TOXICS FROM OPEN BURNING: A COMPREHENSIVE REVIEW

EPA Science Inventory

A detailed literature search was performed to collect and collate available data reporting emissions of organic air toxics from open burning sources. Availability of data varied according to the source and the class of air toxics of interest, and there were several sources for wh...

Evaluation of the Polyethylene Reverse Sampler as a Dosing System in Marine Phase II Whole Sediment Toxicity Identification Evaluations (TIEs)

EPA Science Inventory

Contaminated marine sediments can cause acute and chronic impairments to benthic organisms. Nonionic organic contaminants (NOCs) are often a primary cause of impairment. Toxicity Identification Evaluations (TIEs) are used to identify chemicals causing toxicity in sediments. Ph...

Toxic Leadership in Educational Organizations

ERIC Educational Resources Information Center

Green, James E.

2014-01-01

While research on the traits and skills of effective leaders is plentiful, only recently has the phenomenon of toxic leadership begun to be investigated. This research report focuses on toxic leadership in educational organizations--its prevalence, as well as the characteristics and early indicators. Using mixed methods, the study found four…

Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans

PubMed Central

Tuck, Laura R.; Altenbach, Kirsten; Ang, Thiau Fu; Crawshaw, Adam D.; Campopiano, Dominic J.; Clarke, David J.; Marles-Wright, Jon

2016-01-01

The breakdown of fucose and rhamnose released from plant cell walls by the cellulolytic soil bacterium Clostridium phytofermentans produces toxic aldehyde intermediates. To enable growth on these carbon sources, the pathway for the breakdown of fucose and rhamnose is encapsulated within a bacterial microcompartment (BMC). These proteinaceous organelles sequester the toxic aldehyde intermediates and allow the efficient action of acylating aldehyde dehydrogenase enzymes to produce an acyl-CoA that is ultimately used in substrate-level phosphorylation to produce ATP. Here we analyse the kinetics of the aldehyde dehydrogenase enzyme from the fucose/rhamnose utilisation BMC with different short-chain fatty aldehydes and show that it has activity against substrates with up to six carbon atoms, with optimal activity against propionaldehyde. We have also determined the X-ray crystal structure of this enzyme in complex with CoA and show that the adenine nucleotide of this cofactor is bound in a distinct pocket to the same group in NAD+. This work is the first report of the structure of CoA bound to an aldehyde dehydrogenase enzyme and our crystallographic model provides important insight into the differences within the active site that distinguish the acylating from non-acylating aldehyde dehydrogenase enzymes. PMID:26899032

Insight into Coenzyme A cofactor binding and the mechanism of acyl-transfer in an acylating aldehyde dehydrogenase from Clostridium phytofermentans.

PubMed

Tuck, Laura R; Altenbach, Kirsten; Ang, Thiau Fu; Crawshaw, Adam D; Campopiano, Dominic J; Clarke, David J; Marles-Wright, Jon

2016-02-22

The breakdown of fucose and rhamnose released from plant cell walls by the cellulolytic soil bacterium Clostridium phytofermentans produces toxic aldehyde intermediates. To enable growth on these carbon sources, the pathway for the breakdown of fucose and rhamnose is encapsulated within a bacterial microcompartment (BMC). These proteinaceous organelles sequester the toxic aldehyde intermediates and allow the efficient action of acylating aldehyde dehydrogenase enzymes to produce an acyl-CoA that is ultimately used in substrate-level phosphorylation to produce ATP. Here we analyse the kinetics of the aldehyde dehydrogenase enzyme from the fucose/rhamnose utilisation BMC with different short-chain fatty aldehydes and show that it has activity against substrates with up to six carbon atoms, with optimal activity against propionaldehyde. We have also determined the X-ray crystal structure of this enzyme in complex with CoA and show that the adenine nucleotide of this cofactor is bound in a distinct pocket to the same group in NAD(+). This work is the first report of the structure of CoA bound to an aldehyde dehydrogenase enzyme and our crystallographic model provides important insight into the differences within the active site that distinguish the acylating from non-acylating aldehyde dehydrogenase enzymes.

c-Type Cytochrome Assembly Is a Key Target of Copper Toxicity within the Bacterial Periplasm

PubMed Central

Durand, Anne; Azzouzi, Asma; Bourbon, Marie-Line; Steunou, Anne-Soisig; Liotenberg, Sylviane; Maeshima, Akinori; Astier, Chantal; Argentini, Manuela; Saito, Shingo

2015-01-01

ABSTRACT In the absence of a tight control of copper entrance into cells, bacteria have evolved different systems to control copper concentration within the cytoplasm and the periplasm. Central to these systems, the Cu+ ATPase CopA plays a major role in copper tolerance and translocates copper from the cytoplasm to the periplasm. The fate of copper in the periplasm varies among species. Copper can be sequestered, oxidized, or released outside the cells. Here we describe the identification of CopI, a periplasmic protein present in many proteobacteria, and show its requirement for copper tolerance in Rubrivivax gelatinosus. The ΔcopI mutant is more susceptible to copper than the Cu+ ATPase copA mutant. CopI is induced by copper, localized in the periplasm and could bind copper. Interestingly, copper affects cytochrome c membrane complexes (cbb3 oxidase and photosystem) in both ΔcopI and copA-null mutants, but the causes are different. In the copA mutant, heme and chlorophyll synthesis are affected, whereas in ΔcopI mutant, the decrease is a consequence of impaired cytochrome c assembly. This impact on c-type cytochromes would contribute also to the copper toxicity in the periplasm of the wild-type cells when they are exposed to high copper concentrations. PMID:26396241

How can we take advantage of halophyte properties to cope with heavy metal toxicity in salt-affected areas?

PubMed Central

Lutts, Stanley; Lefèvre, Isabelle

2015-01-01

Background Many areas throughout the world are simultaneously contaminated by high concentrations of soluble salts and by high concentrations of heavy metals that constitute a serious threat to human health. The use of plants to extract or stabilize pollutants is an interesting alternative to classical expensive decontamination procedures. However, suitable plant species still need to be identified for reclamation of substrates presenting a high electrical conductivity. Scope Halophytic plant species are able to cope with several abiotic constraints occurring simultaneously in their natural environment. This review considers their putative interest for remediation of polluted soil in relation to their ability to sequester absorbed toxic ions in trichomes or vacuoles, to perform efficient osmotic adjustment and to limit the deleterious impact of oxidative stress. These physiological adaptations are considered in relation to the impact of salt on heavy metal bioavailabilty in two types of ecosystem: (1) salt marshes and mangroves, and (2) mine tailings in semi-arid areas. Conclusions Numerous halophytes exhibit a high level of heavy metal accumulation and external NaCl may directly influence heavy metal speciation and absorption rate. Maintenance of biomass production and plant water status makes some halophytes promising candidates for further management of heavy-metal-polluted areas in both saline and non-saline environments. PMID:25672360

Surfactant Dysfunction in ARDS and Bronchiolitis is Repaired with Cyclodextrins.

PubMed

Al-Saiedy, Mustafa; Gunasekara, Lasantha; Green, Francis; Pratt, Ryan; Chiu, Andrea; Yang, Ailian; Dennis, John; Pieron, Cora; Bjornson, Candice; Winston, Brent; Amrein, Matthias

2018-03-01

Acute respiratory distress syndrome (ARDS) is caused by many factors including inhalation of toxicants, acute barotrauma, acid aspiration, and burns. Surfactant function is impaired in ARDS and acute airway injury resulting in high surface tension with alveolar and small airway collapse, edema, hypoxemia, and death. In this study, we explore the mechanisms whereby surfactant becomes dysfunctional in ARDS and bronchiolitis and its repair with a cyclodextrin drug that sequesters cholesterol. We used in vitro model systems, a mouse model of ARDS, and samples from patients with acute bronchiolitis. Surface tension was measured by captive bubble surfactometry. Patient samples showed severe surfactant inhibition even in the absence of elevated cholesterol levels. Surfactant was also impaired in ARDS mice where the cholesterol to phospholipid ratio (W/W%) was increased. Methyl-β-cyclodextrin (MβCD) restored surfactant function to normal in both human and animal samples. Model studies showed that the inhibition of surfactant was due to both elevated cholesterol and an interaction between cholesterol and oxidized phospholipids. MβCD was also shown to have anti-inflammatory effects. Inhaled cyclodextrins have potential for the treatment of ARDS. They could be delivered in a portable device carried in combat and used following exposure to toxic gases and fumes or shock secondary to hemorrhage and burns.

Influences of calcium silicate on chemical forms and subcellular distribution of cadmium in Amaranthus hypochondriacus L.

NASA Astrophysics Data System (ADS)

Lu, Huanping; Li, Zhian; Wu, Jingtao; Shen, Yong; Li, Yingwen; Zou, Bi; Tang, Yetao; Zhuang, Ping

2017-01-01

A pot experiment was conducted to investigate the effects of calcium silicate (CS) on the subcellular distribution and chemical forms of cadmium (Cd) in grain amaranths (Amaranthus hypochondriacus L. Cv. ‘K112’) grown in a Cd contaminated soil. Results showed that the dry weight and the photosynthetic pigments contents in grain amaranths increased significantly with the increasing doses of CS treatments, with the highest value found for the treatment of CS3 (1.65 g/kg). Compared with the control, application of CS4 (3.31 g/kg) significantly reduced Cd concentrations in the roots, stems and leaves of grain amaranths by 68%, 87% and 89%, respectively. At subcellular level, CS treatment resulted in redistribution of Cd, higher percentages of Cd in the chloroplast and soluble fractions in leaves of grain amaranths were found, while lower proportions of Cd were located at the cell wall of the leaves. The application of CS enhanced the proportions of pectate and protein integrated forms of Cd and decreased the percentages of water soluble Cd potentially associated with toxicity in grain amaranths. Changes of free Cd ions into inactive forms sequestered in subcellular compartments may indicate an important mechanism of CS for alleviating Cd toxicity and accumulation in plants.

Selenium and 17 other largely essential and toxic metals in muscle and organ meats of Red Deer (Cervus elaphus)--consequences to human health.

PubMed

Jarzyńska, Grażyna; Falandysz, Jerzy

2011-07-01

Concentrations, composition and interrelationships of selenium and metallic elements (Ag, Ba, Cd, Co, Cr, Cs, Cu, Ga, Mn, Mo, Pb, Rb, Sb, Sr, Tl, V and Zn) have been examined in muscle and organ meats of Red Deer hunted in Poland. The analytical data obtained were also discussed in terms of Se supplementation and deficit to Deer as well as the benefits and risk to humans associated with the essential and toxic metals intake resulting from consumption of Deer meat and products. These elements were determined in 20 adult animals of both sexes that were obtained in the 2000/2001 hunting season from Warmia and Mazury in the north-eastern part of Poland. The whole kidneys contained Ba, Cd, Cr, Ga, Pb, Se, Sr and Tl at statistically greater concentrations than liver or muscle tissue from the same animal. Liver showed statistically greater concentrations of Ag, Co, Cu, Mn and Mo than kidneys or muscle tissue, and muscle tissue was richer in Zn, when compared to the kidneys or liver. Cs and Rb were similarly distributed between all three tissue types, while V was less abundant in liver than kidneys or muscle tissue. There were significant associations between some metallic elements retained in Red Deer demonstrated by Principal Component Analysis (PCA) of the data set. In organ and muscle meats (kidneys, liver and muscle tissue considered together) the first principal component (PC1) was strongly influenced by positively correlated variables describing Se, Ba and Cd and negatively correlated variables describing Ag, Co, Cs, Mn, Pb, Tl and V; PC2, respectively, by Cu, Mn and Mo (+) and Zn (-); PC3 by Ga (+) and PC4 by Sb (+). Selenium occurred in muscle tissue, liver and kidneys at median concentrations of 0.13, 0.19 and 4.0mg/g dry weight, respectively. These values can be defined as marginally deficient (< 0.6mg Se/kg liver dw) or satisfactory (≤ 3.0mg Se/kg kidneys dw) for the amount required to maintain the Deer's body condition and health, depending on the criterion for supplementation used. In terms of human nutritional needs, a relatively high selenium content of kidneys can be beneficial. The muscle meat, liver and kidneys of Red Deer can be considered as a very good source of essential Co, Cr, Cu, Mo, Mn, Se and Zn in the human diet. Lead is generally considered as toxic, and the concentrations found in Red Deer (via the food chain intake) were well below the European Union tolerance limit. Pb from the lead bullets can always create food hygienic problem, if not well recognized during sanitary inspection, and this was noted for one muscle meat sample in this study (5% surveyed). There is no tolerance limit of Cd in game animal meats. The median values of Cd noted in fresh muscle tissue, liver and whole kidneys were 0.07, 0.18, and 3.3mg/kg wet weight, respectively. Cd exists as a chemical element present at trace levels in plants and mushrooms in Deer's food chain in background (uncontaminated) areas. When these are consumed by the Deer, the amount of Cd sequestered with metallothioneins and retained in the organ and muscle meat in this study is low enough to be considered safe for human consumption. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effects of water quality parameters on boron toxicity to Ceriodaphnia dubia.

PubMed

Dethloff, Gail M; Stubblefield, William A; Schlekat, Christian E

2009-07-01

The potential modifying effects of certain water quality parameters (e.g., hardness, alkalinity, pH) on the acute toxicity of boron were tested using a freshwater cladoceran, Ceriodaphnia dubia. By comparison, boron acute toxicity was less affected by water quality characteristics than some metals (e.g., copper and silver). Increases in alkalinity over the range tested did not alter toxicity. Increases in water hardness appeared to have an effect with very hard waters (>500 mg/L as CaCO(3)). Decreased pH had a limited influence on boron acute toxicity in laboratory waters. Increasing chloride concentration did not provide a protective effect. Boron acute toxicity was unaffected by sodium concentrations. Median acute lethal concentrations (LC(50)) in natural water samples collected from three field sites were all greater than in reconstituted laboratory waters that matched natural waters in all respects except for dissolved organic carbon. Water effect ratios in these waters ranged from 1.4 to 1.8. In subsequent studies using a commercially available source of natural organic matter, acute toxicity decreased with increased dissolved organic carbon, suggesting, along with the natural water studies, that dissolved organic carbon should be considered further as a modifier of boron toxicity in natural waters where it exceeds 2 mg/L.

Using enzyme bioassays as a rapid screen for metal toxicity

USGS Publications Warehouse

Choate, LaDonna M.; Ross, P.E.; Blumenstein, E. P.; Ranville, James F.

2005-01-01

Mine tailings piles and abandoned mine soils are often contaminated by a suite of toxic metals, which were released in the mining process. Traditionally, toxicity of such areas has been determined by numerous chemical methods including the Toxicity Characteristic Leachate Procedure (TCLP) and traditional toxicity tests using organisms such as the cladoceran Ceriodaphnia dubia. Such tests can be expensive and time-consuming. Enzymatic bioassays may provide an easier, less costly, and more time-effective toxicity screening procedure for mine tailings and abandoned mine soil leachates. This study evaluated the commercially available MetPLATE™ enzymatic toxicity assay test kit. The MetPLATE™ assay uses a modified strain of Escherichia coli bacteria as the test organism. Toxicity is defined by the activity of β-galactosidase enzyme which is monitored colorometrically with a 96-well spectrophotometer. The study used water samples collected from North Fork Clear Creek, a mining influenced water (MIW) located in Colorado. A great benefit to using the MetPLATE™ assay over the TCLP is that it shows actual toxicity of a sample by taking into account the bioavailability of the toxicants rather than simply measuring the metal concentration present. Benefits of the MetPLATE™ assay over the use of C. dubia include greatly reduced time for the testing process (∼2 hours), a more continuous variable due to a greater number of organisms present in each sample (100,000+), and the elimination of need to maintain a culture of organisms at all times.

Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models.

PubMed

Pfohl-Leszkowicz, A; Hadjeba-Medjdoub, K; Ballet, N; Schrickx, J; Fink-Gremmels, J

2015-01-01

The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease in cell viability, but at the same time increased the OTA-DNA adducts formation. These findings indicate the need for an in-depth characterisation of yeast-based products used as mycotoxin-mitigating feed additives, in in vivo models with target animal species taking into account not only their ability to sequester toxins in the gastrointestinal tract but also their potential effects on the biotransformation of mycotoxins.

TOXICITY OF CLAY FLOCCULATION OF RED TIDE ORGANISMS ON BENTHIC ORGANISMS ERF 2001

EPA Science Inventory

Toxicity of Clay Flocculation of Red Tide Organisms on Benthic Organisms (Abstract). To be presented at the16th Biennial Conference of the Estuarine Research Foundation, ERF 2001: An Estuarine Odyssey, 4-8 November 2001, St. Pete Beach, FL. 1 p. (ERL,GB R854).

We have eva...

Organic textile waste as a resource for sustainable agriculture in arid and semi-arid areas.

PubMed

Eriksson, Bo G

2017-03-01

New vegetation in barren areas offers possibilities for sequestering carbon in the soil. Arid and semi-arid areas (ASAs) are candidates for new vegetation. The possibility of agriculture in ASAs is reviewed, revealing the potential for cultivation by covering the surface with a layer of organic fibres. This layer collects more water from humidity in the air than does the uncovered mineral surface, and creates a humid environment that promotes microbial life. One possibility is to use large amounts of organic fibres for soil enhancement in ASAs. In the context of the European Commission Waste Framework Directive, the possibility of using textile waste from Sweden is explored. The costs for using Swedish textile waste are high, but possible gains are the sale of agricultural products and increased land prices as well as environmental mitigation. The findings suggest that field research on such agriculture in ASAs should start as soon as possible.

Crossroads of Wnt and Hippo in epithelial tissues.

PubMed

Bernascone, Ilenia; Martin-Belmonte, Fernando

2013-08-01

Epithelial tissues undergo constant growth and differentiation during embryonic development and to replace damaged tissue in adult organs. These processes are governed by different signaling pathways that ultimately control the expression of genes associated with cell proliferation, patterning, and death. One essential pathway is Wnt, which controls tubulogenesis in several epithelial organs. Recently, Wnt has been closely linked to other signaling pathways, such as Hippo, that orchestrate proliferation and apoptosis to control organ size. There is evidence that epithelial cell junctions may sequester the transcription factors that act downstream of these signaling pathways, which would represent an important aspect of their functional regulation and their influence on cell behavior. Here, we review the transcriptional control exerted by the Wnt and Hippo signaling pathways during epithelial growth, patterning, and differentiation and recent advances in understanding of the regulation and crosstalk of these pathways in epithelial tissues. Copyright © 2013 Elsevier Ltd. All rights reserved.

Catalytic Destruction Of Toxic Organic Compounds

NASA Technical Reports Server (NTRS)

Voecks, Gerald E.

1990-01-01

Proposed process disposes of toxic organic compounds in contaminated soil or carbon beds safely and efficiently. Oxidizes toxic materials without producing such other contaminants as nitrogen oxides. Using air, fuel, catalysts, and steam, system consumes less fuel and energy than decontamination processes currently in use. Similar process regenerates carbon beds used in water-treatment plants.

USING STRUCTURAL EFFECTS ON THE ORGANIZATION OF THE CYTOSKELETON OF RAINBOW TROUT HEPATOCYTES TO SORT PATHWAYS OF REACTIVE TOXICITY

EPA Science Inventory

Quinones have been shown to be more acutely toxic to aquatic organisms than chemicals that are not capable of either direct interaction with cellular nucleophiles or potentially metabolized free radicals. For the development of accurate QSAR models, in vitro toxicity assays are n...

Landscape-level controls on dissolved carbon flux from diverse catchments of the circumboreal

USGS Publications Warehouse

Tank, Suzanne; Frey, Karen E.; Striegl, Robert G.; Raymond, Peter A.; Holmes, R. Max; McClelland, James W.; Peterson, Bruce J.

2012-01-01

While much of the dissolved organic carbon (DOC) within rivers is destined for mineralization to CO2, a substantial fraction of riverine bicarbonate (HCO3-) flux represents a CO2 sink, as a result of weathering processes that sequester CO2 as HCO3-. We explored landscape-level controls on DOC and HCO3- flux in subcatchments of the boreal, with a specific focus on the effect of permafrost on riverine dissolved C flux. To do this, we undertook a multivariate analysis that partitioned the variance attributable to known, key regulators of dissolved C flux (runoff, lithology, and vegetation) prior to examining the effect of permafrost, using riverine biogeochemistry data from a suite of subcatchments drawn from the Mackenzie, Yukon, East, and West Siberian regions of the circumboreal. Across the diverse catchments that we study, controls on HCO3- flux were near-universal: runoff and an increased carbonate rock contribution to weathering (assessed as riverwater Ca:Na) increased HCO3- yields, while increasing permafrost extent was associated with decreases in HCO3-. In contrast, permafrost had contrasting and region-specific effects on DOC yield, even after the variation caused by other key drivers of its flux had been accounted for. We used ionic ratios and SO4 yields to calculate the potential range of CO2 sequestered via weathering across these boreal subcatchments, and show that decreasing permafrost extent is associated with increases in weathering-mediated CO2 fixation across broad spatial scales, an effect that could counterbalance some of the organic C mineralization that is predicted with declining permafrost.

ISOLATING AND FRACTIONATING ORGANIC TOXICANTS IN SEDIMENTS: EVALUATION OF AN EXPERIMENTAL APPROACH

EPA Science Inventory

Most solid-phase sediment TIE techniques for organic chemicals have been focused on solid phase sorptive techniques, such as amending contaminated sediments with the carbonaceousresin, Ambersorb coconut charcoal, or XAD resin to reduce toxicity caused by organic contaminants. Cha...

Mercury tissue residue approach in Chironomus riparius: Involvement of toxicokinetics and comparison of subcellular fractionation methods.

PubMed

Gimbert, Frédéric; Geffard, Alain; Guédron, Stéphane; Dominik, Janusz; Ferrari, Benoit J D

2016-02-01

Along with the growing body of evidence that total internal concentration is not a good indicator of toxicity, the Critical Body Residue (CBR) approach recently evolved into the Tissue Residue Approach (TRA) which considers the biologically active portion of metal that is available to contribute to the toxicity at sites of toxic action. For that purpose, we examined total mercury (Hg) bioaccumulation and subcellular fractionation kinetics in fourth stage larvae of the midge Chironomus riparius during a four-day laboratory exposure to Hg-spiked sediments and water. The debris (including exoskeleton, gut contents and cellular debris), granule and organelle fractions accounted only for about 10% of the Hg taken up, whereas Hg concentrations in the entire cytosolic fraction rapidly increased to approach steady-state. Within this fraction, Hg compartmentalization to metallothionein-like proteins (MTLP) and heat-sensitive proteins (HSP), consisting mostly of enzymes, was assessed in a comparative manner by two methodologies based on heat-treatment and centrifugation (HT&C method) or size exclusion chromatography separation (SECS method). The low Hg recoveries obtained with the HT&C method prevented accurate analysis of the cytosolic Hg fractionation by this approach. According to the SECS methodology, the Hg-bound MTLP fraction increased linearly over the exposure duration and sequestered a third of the Hg flux entering the cytosol. In contrast, the HSP fraction progressively saturated leading to Hg excretion and physiological impairments. This work highlights several methodological and biological aspects to improve our understanding of Hg toxicological bioavailability in aquatic invertebrates. Copyright © 2015 Elsevier B.V. All rights reserved.

A toxic organic solvent-free technology for the preparation of PEGylated paclitaxel nanosuspension based on human serum albumin for effective cancer therapy

PubMed Central

Yin, Tingjie; Dong, Lihui; Cui, Bei; Wang, Lei; Yin, Lifang; Zhou, Jianping; Huo, Meirong

2015-01-01

Clinically, paclitaxel (PTX) is one of most commonly prescribed therapies against a wide range of solid neoplasms. Despite its success, the clinical applicability of PTX (Taxol®) is severely hampered by systemic toxicities induced by Cremophor EL. While attempts to bypass the need for Cremophor EL have been developed through platforms such as Abraxane™, nab™ relies heavily on the use of organic solvents, namely, chloroform. The toxicity introduced by residual chloroform poses a potential risk to patient health. To mitigate the toxicities of toxic organic solvent-based manufacture methods, we have designed a method for the formulation of PTX nanosuspensions (PTX-PEG [polyethylene glycol]-HSA [human serum albumin]) that eliminates the dependence on toxic organic solvents. Coined the solid-dispersion technology, this technique permits the dispersion of PTX into PEG skeleton without the use of organic solvents or Cremophor EL as a solubilizer. Once the PTX-PEG dispersion is complete, the dispersion can be formulated with HSA into nanosuspensions suitable for intravenous administration. Additionally, the incorporation of PEG permits the prolonged circulation through the steric stabilization effect. Finally, HSA-mediated targeting permits active receptor-mediated endocytosis for enhanced tumor uptake and reduced side effects. By eliminating the need for both Cremophor EL and organic solvents while simultaneously increasing antitumor efficacy, this method provides a superior alternative to currently accepted methods for PTX delivery. PMID:26715846

Aquatic toxicity information retrieval data base (aquire for non-vms) (on magnetic tape). Data file

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The AQUIRE-AQUatic toxicity information REtrieval-data base was established in 1981 by the United States Environmental Protection Agency (US EPA), Office of Pesticide and Toxic Substances. AQUIRE continues to be updated and maintained at the US EPA Environmental Research Laboratory-Duluth. The purpose of AQUIRE is to provide scientists and managers quick access to a comprehensive, systematic, computerized compilation of aquatic toxic effects data for freshwater and marine organisms. The AQUIRE system is one of the foremost resources for the location of aquatic toxicity information and is commonly used to evaluate and prioritize the hazards of industrial chemicals and pesticides in themore » USA and abroad. Scientific papers published both nationally and internationally on the toxicity of chemicals to aquatic organisms and plants are collected and reviewed for AQUIRE. Independently compiled data files that meet AQUIRE parameter and quality assurance criteria are also included. Relevant toxicity test results and related test information for any individual chemicals analyzed using freshwater and marine organisms in laboratory and field conditions, are included in the database. Since 1994, nine data updates were made to the AQUIRE system. AQUIRE now contains 129,740 individual aquatic toxicity test results for 5,679 chemicals, 2,827 organisms, and over 160 endpoints reviewed from 7,517 publications. Over 16,000 of the AQUIRE records represent aquatic toxicity data reported in the literature for the publication years 1989-1991. AQUIRE offers data contributed through an international data exchange clearinghouse with the Organization for Economic Cooperation and Development (OECD) and the Borok Institute in Russia. The current release of AQUIRE delivers data submitted from Germany, The Netherlands, and Russia.« less

Transthyretin Sequesters Amyloid β Protein and Prevents Amyloid Formation

NASA Astrophysics Data System (ADS)

Schwarzman, Alexander L.; Gregori, Luisa; Vitek, Michael P.; Lyubski, Sergey; Strittmatter, Warren J.; Enghilde, Jan J.; Bhasin, Ramaninder; Silverman, Josh; Weisgraber, Karl H.; Coyle, Patricia K.; Zagorski, Michael G.; Talafous, Joseph; Eisenberg, Moises; Saunders, Ann M.; Roses, Allen D.; Goldgaber, Dmitry

1994-08-01

The cardinal pathological features of Alzheimer disease are depositions of aggregated amyloid β protein (Aβ) in the brain and cerebrovasculature. However, the Aβ is found in a soluble form in cerebrospinal fluid in healthy individuals and patients with Alzheimer disease. We postulate that sequestration of Aβ precludes amyloid formation. Failure to sequester Aβ in Alzheimer disease may result in amyloidosis. When we added Aβ to cerebrospinal fluid of patients and controls it was rapidly sequestered into stable complexes with transthyretin. Complexes with apolipoprotein E, which has been shown to bind Aβ in vitro, were not observed in cerebrospinal fluid. Additional in vitro studies showed that both purified transthyretin and apolipoprotein E prevent amyloid formation.

Cryoprotectant Toxicity: Facts, Issues, and Questions

PubMed Central

2015-01-01

Abstract High levels of penetrating cryoprotectants (CPAs) can eliminate ice formation during cryopreservation of cells, tissues, and organs to cryogenic temperatures. But CPAs become increasingly toxic as concentration increases. Many strategies have been attempted to overcome the problem of eliminating ice while minimizing toxicity, such as attempting to optimize cooling and warming rates, or attempting to optimize time of adding individual CPAs during cooling. Because strategies currently used are not adequate, CPA toxicity remains the greatest obstacle to cryopreservation. CPA toxicity stands in the way of cryogenic cryopreservation of human organs, a procedure that has the potential to save many lives. This review attempts to describe what is known about CPA toxicity, theories of CPA toxicity, and strategies to reduce CPA toxicity. Critical analysis and suggestions are also included. PMID:25826677

Natural remedies for non-steroidal anti-inflammatory drug-induced toxicity.

PubMed

Simon, Jerine Peter; Evan Prince, Sabina

2017-01-01

The liver is an important organ of the body, which has a vital role in metabolic functions. The non-steroidal anti-inflammatory drug (NSAID), diclofenac causes hepato-renal toxicity and gastric ulcers. NSAIDs are noted to be an agent for the toxicity of body organs. This review has elaborated various scientific perspectives of the toxicity caused by diclofenac and its mechanistic action in affecting the vital organ. This review suggests natural products are better remedies than current clinical drugs against the toxicity caused by NSAIDs. Natural products are known for their minimal side effects, low cost and availability. On the other hand, synthetic drugs pose the danger of adverse effects if used frequently or over a long period. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

[Sequential course and prospective management of ifosfamide-induced multi-organ toxicity].

PubMed

Mollenkopf, A; du Bois, A; Meerpohl, H G

1996-10-01

We report on an 66-year old female in whom we diagnosed uterine carcinosarcoma and concurrent breast cancer. As first-line treatment the patient received ifosfamide 4.8 mg/m2 body surface. During her second course of chemotherapy she developed sequentially life-threatening toxicities; severe emesis followed by nephrotoxicity, neurotoxicity and myelosuppression. Early prophylactic administration of rhG-CSF (Filgrastim) helped to overcome severe, potentially fatal myelosuppression. The course of severe toxicities following high doses of ifosfamide might reflect a dependent sequence, where one organ failure causes a subsequent organ failure. Prophylactic treatment of anticipated toxicity should be considered for the management of severe ifosfamide-induced toxicity. Such treatment may consist of sufficient antiemesis, sufficient hydration, as well as a therapy with methylene blue in case of severe neurotoxicity.

Aquatic toxicity information retrieval data base (AQUIRE). Data file

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The purpose of AQUIRE is to provide scientists and managers quick access to a comprehensive, systematic, computerized compilation of aquatic toxicity data. Scientific papers published both nationally and internationally on the toxicity of chemicals to aquatic organisms and plants are collected and reviewed for AQUIRE. Independently compiled data files that meet AQUIRE parameter and quality assurance criteria are also included. Relevant toxicity test results and related test information for any individual chemicals analyzed using freshwater and marine organisms in laboratory and field conditions, are included in the database. During 1992 and early 1993, nine data updates were made to themore » AQUIRE system. AQUIRE now contains 109,338 individual aquatic toxicity test results for 5,159 chemicals, 2,429 organisms, and over 160 endpoints reviewed from 7,517 publications.« less

Using ultrahigh-resolution mass spectrometry and toxicity identification techniques to characterize the toxicity of oil sands process-affected water: The case for classical naphthenic acids.

PubMed

Hughes, Sarah A; Mahaffey, Ashley; Shore, Bryon; Baker, Josh; Kilgour, Bruce; Brown, Christine; Peru, Kerry M; Headley, John V; Bailey, Howard C

2017-11-01

Previous assessments of oil sands process-affected water (OSPW) toxicity were hampered by lack of high-resolution analytical analysis, use of nonstandard toxicity methods, and variability between OSPW samples. We integrated ultrahigh-resolution mass spectrometry with a toxicity identification evaluation (TIE) approach to quantitatively identify the primary cause of acute toxicity of OSPW to rainbow trout (Oncorhynchus mykiss). The initial characterization of OSPW toxicity indicated that toxicity was associated with nonpolar organic compounds, and toxicant(s) were further isolated within a range of discrete methanol fractions that were then subjected to Orbitrap mass spectrometry to evaluate the contribution of naphthenic acid fraction compounds to toxicity. The results showed that toxicity was attributable to classical naphthenic acids, with the potency of individual compounds increasing as a function of carbon number. Notably, the mass of classical naphthenic acids present in OSPW was dominated by carbon numbers ≤16; however, toxicity was largely a function of classical naphthenic acids with ≥17 carbons. Additional experiments found that acute toxicity of the organic fraction was similar when tested at conductivities of 400 and 1800 μmhos/cm and that rainbow trout fry were more sensitive to the organic fraction than larval fathead minnows (Pimephales promelas). Collectively, the results will aid in developing treatment goals and targets for removal of OSPW toxicity in water return scenarios both during operations and on mine closure. Environ Toxicol Chem 2017;36:3148-3157. © 2017 SETAC. © 2017 SETAC.

Conditions of persistent oil on beaches in Prince William Sound 26 years after the Exxon Valdez spill

NASA Astrophysics Data System (ADS)

Lindeberg, Mandy R.; Maselko, Jacek; Heintz, Ron A.; Fugate, Corey J.; Holland, Larry

2018-01-01

On March 24, 1989, the Exxon Valdez grounded on Bligh Reef in Prince William Sound, Alaska, spilling an estimated 10.8 million gallons of crude oil. Contrary to early projections, subsequent studies over several decades have shown subsurface oil persisting on impacted beaches. Here we present findings from a lingering oil survey conducted during the summer of 2015 at a small set of beaches in Prince William Sound known to have persistent subsurface Exxon Valdez oil. The objectives of the survey were to estimate how much oil remains at these sites, the oil composition, and oil retention rates compared to previous studies. Results from the survey found lingering oil was present at 8 of 9 sites that were revisited. Surveys revealed little evidence of change in oil area or mass over the last 14 years, nor has there been a change in the distribution of oiling intensities or their location on the beach. Detailed analysis of the oil indicated it has not weathered since 2001. Subsurface oils collected in 2015 have enriched concentrations of phenanthrenes and chrysenes relative to oil originating in the cargo hold indicating that buried oil has retained some toxic potential over the last two decades, but it is not currently bioavailable. Subsurface oil appears to be sequestered in sediments and protected from hydrological washing and low oxygen and nutrient levels inhibiting biodegradation. These findings are consistent with previous surveys and predictive geomorphic models suggesting the estimated 0.6% Exxon Valdez oil remaining is sequestered and not bioavailable unless disturbed and will likely persist in the environment on a decadal scale.

Application of the target lipid model and passive samplers to characterize the toxicity of bioavailable organics in oil sands process-affected water.

PubMed

Redman, Aaron D; Parkerton, Thomas F; Butler, Josh David; Letinski, Daniel J; Frank, Richard A; Hewitt, L Mark; Bartlett, Adrienne J; Gillis, Patricia Leigh; Marentette, Julie R; Parrott, Joanne L; Hughes, Sarah A; Guest, Rodney; Bekele, Asfaw; Zhang, Kun; Morandi, Garrett; Wiseman, Steve B; Giesy, John P

2018-06-14

Oil sand operations in Alberta, Canada will eventually include returning treated process-affected waters to the environment. Organic constituents in oil sand process-affected water (OSPW) represent complex mixtures of nonionic and ionic (e.g. naphthenic acids) compounds, and compositions can vary spatially and temporally, which has impeded development of water quality benchmarks. To address this challenge, it was hypothesized that solid phase microextraction fibers coated with polydimethylsiloxane (PDMS) could be used as a biomimetic extraction (BE) to measure bioavailable organics in OSPW. Organic constituents of OSPW were assumed to contribute additively to toxicity, and partitioning to PDMS was assumed to be predictive of accumulation in target lipids, which were the presumed site of action. This method was tested using toxicity data for individual model compounds, defined mixtures, and organic mixtures extracted from OSPW. Toxicity was correlated with BE data, which supports the use of this method in hazard assessments of acute lethality to aquatic organisms. A species sensitivity distribution (SSD), based on target lipid model and BE values, was similar to SSDs based on residues in tissues for both nonionic and ionic organics. BE was shown to be an analytical tool that accounts for bioaccumulation of organic compound mixtures from which toxicity can be predicted, with the potential to aid in the development of water quality guidelines.

Application of the Activity Framework for Assessing Aquatic Ecotoxicology Data for Organic Chemicals.

PubMed

Thomas, Paul; Dawick, James; Lampi, Mark; Lemaire, Philippe; Presow, Shaun; van Egmond, Roger; Arnot, Jon A; Mackay, Donald; Mayer, Philipp; Galay Burgos, Malyka

2015-10-20

Toxicological research in the 1930s gave the first indications of the link between narcotic toxicity and the chemical activity of organic chemicals. More recently, chemical activity has been proposed as a novel exposure parameter that describes the fraction of saturation and that quantifies the potential for partitioning and diffusive uptake. In the present study, more than 2000 acute and chronic algal, aquatic invertebrates and fish toxicity data, as well as water solubility and melting point values, were collected from a series of sources. The data were critically reviewed and grouped by mode of action (MoA). We considered 660 toxicity data to be of acceptable quality. The 328 data which applied to the 72 substances identified as MoA 1 were then evaluated within the activity-toxicity framework: EC50 and LC50 values for all three taxa correlated generally well with (subcooled) liquid solubilities. Acute toxicity was typically exerted within the chemical activity range of 0.01-0.1, whereas chronic toxicity was exerted in the range of 0.001-0.01. These results confirm that chemical activity has the potential to contribute to the determination, interpretation and prediction of toxicity to aquatic organisms. It also has the potential to enhance regulation of organic chemicals by linking results from laboratory tests, monitoring and modeling programs. The framework can provide an additional line of evidence for assessing aquatic toxicity, for improving the design of toxicity tests, reducing animal usage and addressing chemical mixtures.

Organic carbon sequestration under selected land use in Padang city, West Sumatra, Indonesia

NASA Astrophysics Data System (ADS)

Yulnafatmawita; Yasin, S.

2018-03-01

Organic carbon is a potential element to build biomass as well as emitting CO2 to the atmosphere and promotes global warming. This research was aimed to calculate the sequestered Carbon (C) within a 1-m soil depth under selected land use from 6 different sites in Padang city, Indonesia. Disturbed and undisturbed soil samples were taken from several horizons until 100 cm depth at each location. Soil parameters observed were organic carbon (OC), bulk density (BD), and soil texture. The result showed that soil OC content tended to decrease by the depth at all land use types, except under rice field in Kurao-Nanggalo which extremely increased at >65 cm soil depth with the highest carbon stock. The soil organic carbon sequestration from the highest to the lowest according to land use and the location is in the following order mix garden- Kayu Aro > mix garden- Aie Pacah > Rangeland- Parak Laweh >seasonal farming- Teluk Sirih > rice field- Kampuang Jua.

A Mouse Click Away: Internet Resources for Students in Crisis in Geographically Isolated or Self-Sequestered Communities

ERIC Educational Resources Information Center

Gary, Juneau Mahan

2010-01-01

The impact, incidence, prevalence, and severity of violence and trauma adversely affect students academically, behaviorally, emotionally, and socially. For students residing in geographically isolated or self-sequestered communities, trauma may be exacerbated when school counselors may be unprepared to respond effectively and timely because…

Process for sequestering carbon dioxide and sulfur dioxide

DOEpatents

Maroto-Valer, M Mercedes [State College, PA; Zhang, Yinzhi [State College, PA; Kuchta, Matthew E [State College, PA; Andresen, John M [State College, PA; Fauth, Dan J [Pittsburgh, PA

2009-10-20

A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Can greening of aquaculture sequester blue carbon?

PubMed

Ahmed, Nesar; Bunting, Stuart W; Glaser, Marion; Flaherty, Mark S; Diana, James S

2017-05-01

Globally, blue carbon (i.e., carbon in coastal and marine ecosystems) emissions have been seriously augmented due to the devastating effects of anthropogenic pressures on coastal ecosystems including mangrove swamps, salt marshes, and seagrass meadows. The greening of aquaculture, however, including an ecosystem approach to Integrated Aquaculture-Agriculture (IAA) and Integrated Multi-Trophic Aquaculture (IMTA) could play a significant role in reversing this trend, enhancing coastal ecosystems, and sequestering blue carbon. Ponds within IAA farming systems sequester more carbon per unit area than conventional fish ponds, natural lakes, and inland seas. The translocation of shrimp culture from mangrove swamps to offshore IMTA could reduce mangrove loss, reverse blue carbon emissions, and in turn increase storage of blue carbon through restoration of mangroves. Moreover, offshore IMTA may create a barrier to trawl fishing which in turn could help restore seagrasses and further enhance blue carbon sequestration. Seaweed and shellfish culture within IMTA could also help to sequester more blue carbon. The greening of aquaculture could face several challenges that need to be addressed in order to realize substantial benefits from enhanced blue carbon sequestration and eventually contribute to global climate change mitigation.

Toxicity of contaminated sediments in dilution series with control sediments

USGS Publications Warehouse

Nelson, M.K.; Landrum, P.F.; Burton, G.A.; Klaine, S.J.; Crecelius, E.A.; Byl, T.D.; Gossiaux, Duane C.; Tsymbal, V.N.; Cleveland, L.; Ingersoll, Christopher G.; Sasson-Brickson, G.

1993-01-01

The use of dilutions has been the foundation of our approach for assessing contaminated water, and accordingly, it may be important to establish similar or parallel approaches for sediment dilutions. Test organism responses to dilution gradients can identify the degree of necessary sediment alteration to reduce the toxicity. Using whole sediment dilutions to represent the complex interactions of in situ sediments can identify the toxicity, but the selection of the appropriate diluent for the contaminated sediment may affect the results and conclusions drawn. Contaminated whole sediments were examined to evaluate the toxicity of dilutions of sediments with a diversity of test organisms. Dilutions of the contaminated sediments were prepared with differing diluents that varied in organic carbon content, particle size distribution, and volatile solids. Studies were conducted using four macroinvertebrates and a vascular, rooted plant. Responses by some test organisms followed a sigmoidal dose-response curve, but others followed a U-shaped curve. Initial dilutions reduced toxicity as expected, but further dilution resulted in an increase in toxicity. The type of diluent used was an important factor in assessing the sediment toxicity, because the control soil reduced toxicity more effectively than sand as a diluent of the same sediment. Using sediment chemical and physical characteristics as an indicator of sediment dilution may not be as useful as chemical analysis of contaminants, but warrants further investigation.

Developing Sediment Remediation Goals at Superfund Sites Based on Pore Water for the Protection of Benthic Organisms from Direct Toxicity to Non-ionic Organic Contaminants

EPA Science Inventory

This document contains a methodology for developing interstitial water remediation goals (IWRGs) for nonionic organic pollutants (toxicants) in sediments for the protection of benthic organisms. The document provides the basis for using the final chronic values (FCVs) from EPA’s...

A COMPARISON OF THE LETHAL AND SUBLETHAL TOXICITY OF ORGANIC CHEMICAL MIXTURES TO THE FATHEAD MINNOW (PIMEPHALES PROMELAS)

EPA Science Inventory

The joint toxic effects of known binary and multiple organic chemical mixtures to the fathead minnow (Pimephales promelas) were defined at both the 96-h 50% lethal effect concentration (LC50) and sublethal (32-d growth) response levels for toxicants with a narcosis I, narcosis II...

Assessment of toxicity of selenium and cadmium selenium quantum dots: A review.

PubMed

Sharma, Virender K; McDonald, Thomas J; Sohn, Mary; Anquandah, George A K; Pettine, Maurizio; Zboril, Radek

2017-12-01

This paper reviews the current understanding of the toxicity of selenium (Se) to terrestrial mammalian and aquatic organisms. Adverse biological effects occur in the case of Se deficiencies, associated with this element having essential biological functions and a narrow window between essentiality and toxicity. Several inorganic species of Se (-2, 0, +4, and +6) and organic species (monomethylated and dimethylated) have been reported in aquatic systems. The toxicity of Se in any given sample depends not only on its speciation and concentration, but also on the concomitant presence of other compounds that may have synergistic or antagonistic effects, affecting the target organism as well, usually spanning 2 or 3 orders of magnitude for inorganic Se species. In aquatic ecosystems, indirect toxic effects, linked to the trophic transfer of excess Se, are usually of much more concern than direct Se toxicity. Studies on the toxicity of selenium nanoparticles indicate the greater toxicity of chemically generated selenium nanoparticles relative to selenium oxyanions for fish and fish embryos while oxyanions of selenium have been found to be more highly toxic to rats as compared to nano-Se. Studies on polymer coated Cd/Se quantum dots suggest significant differences in toxicity of weathered vs. non-weathered QD's as well as a significant role for cadmium with respect to toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of Selected Organic Micropollutants on Organisms

NASA Astrophysics Data System (ADS)

Włodarczyk-Makuła, Maria

2017-03-01

This article describes the toxicity of organic micropollutants on tested microorganisms. Itis a current issue because organic micropollutants are identified in all elements of environmental (surface water, ground water, soils) and in food products. The organic micropollutants include: polychlorinated dibenzodioxyns PCDD, polychlorinated dibenzofurans PCDF, polychlorinated biphenyls PCB, polycyclic aromatic hydrocarbons PAH, halogenated compounds and by-products of water treatment. Some organic compounds cause hazard for health and human life due to their estrogenic biological activity, carcinogenic, mutagenic or teratogenic activity. The influence on organisms indicators of these compounds based on literature data were presented. The level of TEQ (toxic equivalency) in response to organic chlorine derivatives (PCDDs, PCDF, PCBs) is usually determined by toxic equivalency factor (TEF). The International Agency for Research on Cancer classifies organic micropollutants as carcinogenic to humans (Group 1), possibly carcinogenic (Group 2A) or probably carcinogenic to humans (Group 2B).

Renal Cell Toxicity of Water-Soluble Coal Extracts from the Gulf Coast

NASA Astrophysics Data System (ADS)

Ojeda, A. S.; Ford, S.; Ihnat, M.; Gallucci, R. M.; Philp, P. R.

2017-12-01

In the Gulf Coast, many rural residents rely on private well water for drinking, cooking, and other domestic needs. A large portion of this region contains lignite coal deposits within shallow aquifers that potentially leach organic matter into the water supply. It is proposed that the organic matter leached from low-rank coal deposits contributes to the development of kidney disease, however, little work has been done to investigate the toxicity of coal extracts. In this study, human kidney cells (HK-2) were exposed to water-soluble extracts of Gulf Coast Coals to assess toxicity. Cell viability was measured by direct counts of total and necrotic cells. A dose-response curve was used to generate IC50 values, and the extracts showed significant toxicity that ranged from 0.5% w/v to 3% w/v IC50. The most toxic extract was from Louisiana where coal-derived organic material has been previously linked to high incidents of renal pelvic cancer (RPC). Although the toxic threshold measured in this study is significantly higher than the concentration of organic matter in the groundwater, typically <5 mg/L (0.005% w/v), residents in the affected areas may consume contaminated water over a lifetime. It is possible that the cumulative toxic effects of coal-derived material contribute to the development of disease.

Sediment Toxicity Identification Evaluation

EPA Science Inventory

Approach combining chemical manipulations and aquatic toxicity testing, generally with whole organisms, to systematically characterize, identify and confirm toxic substances causing toxicity in whole sediments and sediment interstitial waters. The approach is divided into thre...

Nano-sized polystyrene affects feeding, behavior and physiology of brine shrimp Artemia franciscana larvae.

PubMed

Bergami, Elisa; Bocci, Elena; Vannuccini, Maria Luisa; Monopoli, Marco; Salvati, Anna; Dawson, Kenneth A; Corsi, Ilaria

2016-01-01

Nano-sized polymers as polystyrene (PS) constitute one of the main challenges for marine ecosystems, since they can distribute along the whole water column affecting planktonic species and consequently disrupting the energy flow of marine ecosystems. Nowadays very little knowledge is available on the impact of nano-sized plastics on marine organisms. Therefore, the present study aims to evaluate the effects of 40nm anionic carboxylated (PS-COOH) and 50nm cationic amino (PS-NH2) polystyrene nanoparticles (PS NPs) on brine shrimp Artemia franciscana larvae. No signs of mortality were observed at 48h of exposure for both PS NPs at naplius stage but several sub-lethal effects were evident. PS-COOH (5-100μg/ml) resulted massively sequestered inside the gut lumen of larvae (48h) probably limiting food intake. Some of them were lately excreted as fecal pellets but not a full release was observed. Likewise, PS-NH2 (5-100µg/ml) accumulated in larvae (48h) but also adsorbed at the surface of sensorial antennules and appendages probably hampering larvae motility. In addition, larvae exposed to PS-NH2 undergo multiple molting events during 48h of exposure compared to controls. The activation of a defense mechanism based on a physiological process able to release toxic cationic NPs (PS-NH2) from the body can be hypothesized. The general observed accumulation of PS NPs within the gut during the 48h of exposure indicates a continuous bioavailability of nano-sized PS for planktonic species as well as a potential transfer along the trophic web. Therefore, nano-sized PS might be able to impair food uptake (feeding), behavior (motility) and physiology (multiple molting) of brine shrimp larvae with consequences not only at organism and population level but on the overall ecosystem based on the key role of zooplankton on marine food webs. Copyright © 2015 Elsevier Inc. All rights reserved.

The Identification and Quantification of Oxygenated Polycyclic Aromatic Hydrocarbons in Dissolved Black Carbon (Biochar Leachate)

NASA Astrophysics Data System (ADS)

Mitra, S.; Webb, C.; Zimmerman, A. R.; Bostick, K. W.; Wozniak, A. S.; Hatcher, P.

2017-12-01

The proposed benefits of biochar (residues of the incomplete combustion of biomass) as a carbon-negative soil amendment have led to its wide application in soils. However, recent studies have shown that the compounds in biochar may not be as refractory in the soil environment as previously assumed. For example, mobilization or transformation of the organic molecules in biochar via solubilization, may occur in nature. Such mobilization has the potential to alter biochar's potential to sequester carbon. Moreover, many of the leached molecules may be reactive, toxic and carcinogenic. In this study, we quantified two classes of such compounds, polycyclic aromatic hydrocarbons and oxygenated polycyclic aromatic hydrocarbons (PAHs and OPAHs, respectively) in the solids and leachates of an oak and grass biochar thermal series (pyrolyzed at 400, 525, 650 °C). We compare PAH and OPAH yields and concentrations as a function of the initial biochar feedstock as well as its pyrolysis temperature. Solid biochars yielded considerably higher amounts of total PAHs/OPAHs than the liquid extracts. Grass pyrolyzed at 400°C yielded 4,760 ng/g total PAHs/OPAHs per gram of solid biochar whereas oak pyrolyzed at 650°C contained 2,840 ng/g total PAHs/OPAHs per gram of solid biochar. Preliminary results for oak biochar indicate that solubilization of PAHs and OPAHs is greatest when pyrolyzed at 250 °C with concentrations of 1.64 ng/g total PAHs/OPAHs per gram of aqueous leachate. For grass, the greatest solubilization of PAHs/OPAHs occurs at pyrolysis temperatures of 400°C with 2.94 g/ng total PAHs/OPAHs per gram of aqueous leachate. These experiments will improve our understanding of the mobility of pyrogenic C in the environment and potential for pyrogenic C export from terrestrial systems and negative effects to aquatic ecosystems, and may result in new chemical markers for pyrogenic organic matter in environmental samples.

Baseline toxicity of a chlorobenzene mixture and total body residues measured and estimated with solid-phase microextraction.

PubMed

Leslie, Heather A; Hermens, Joop L M; Kraak, Michiel H S

2004-08-01

Body residues of compounds with a narcotic mode of action that exceed critical levels result in baseline toxicity in organisms. Previous studies have shown that internal concentrations in organisms also can be estimated by way of passive sampling. In this experiment, solid-phase microextraction (SPME) fibers were used as a tool to estimate the body residues, which were then compared to measured levels. Past application of SPME fibers in the assessment of toxicity risk of samples has focused on separate exposure of fibers and organisms, often necessitated by the amount of agitation needed in order to achieve steady state in the fibers within a convenient time period. Uptake kinetic studies have shown that in SPME fibers with thin coatings, equilibrium concentrations can be reached without agitation within the time frame of a toxicity test. In contrast to toxicity experiments to date, the SPME fibers in the current study were exposed concomitantly to the test water with the organisms, ensuring an exposure under the exact same conditions. Fibers and two aquatic invertebrate species were exposed to a mixture of four chlorobenzenes with a narcotic mode of action. The total body residue of these compounds in the organisms was determined, as was the acute toxicity resulting from the accumulation. The total body residues of both species were correlated to the total concentrations in SPME fibers. It was concluded that toxicity could be predicted based on total body residue (TBR) estimates from fiber concentrations.

Analysis of the ecotoxicity data submitted within the framework of the REACH Regulation. Part 3. Experimental sediment toxicity assays.

PubMed

Cesnaitis, Romanas; Sobanska, Marta A; Versonnen, Bram; Sobanski, Tomasz; Bonnomet, Vincent; Tarazona, Jose V; De Coen, Wim

2014-03-15

For the first REACH registration deadline, companies have submitted registrations with relevant hazard and exposure information for substances at the highest tonnage level (above 1000 tonnes per year). At this tonnage level, information on the long-term toxicity of a substance to sediment organisms is required. There are a number of available test guidelines developed and accepted by various national/international organisations, which can be used to investigate long-term toxicity to sediment organisms. However instead of testing, registrants may also use other options to address toxicity to sediment organisms, e.g. weight of evidence approach, grouping of substances and read-across approaches, as well as substance-tailored exposure-driven testing. The current analysis of the data provided in ECHA database focuses on the test methods applied and the test organisms used in the experimental studies to assess long-term toxicity to sediment organisms. The main guidelines used for the testing of substances registered under REACH are the OECD guidelines and OSPAR Protocols on Methods for the Testing of Chemicals used in the Offshore Oil Industry: "Part A: A Sediment Bioassay using an Amphipod Corophium sp." explaining why one of the mostly used test organisms is the marine amphipod Corophium sp. In total, testing results with at least 40 species from seven phyla are provided in the database. However, it can be concluded that the ECHA database does not contain a high enough number of available experimental data on toxicity to sediment organisms for it to be used extensively by the scientific community (e.g. for development of non-testing methods to predict hazards to sediment organisms). © 2013.

Raf Kinase Inhibitory Protein Protects Cells against Locostatin-Mediated Inhibition of Migration

PubMed Central

Shemon, Anne N.; Eves, Eva M.; Clark, Matthew C.; Heil, Gary; Granovsky, Alexey; Zeng, Lingchun; Imamoto, Akira

2009-01-01

Background Raf Kinase Inhibitory Protein (RKIP, also PEBP1), a member of the Phosphatidylethanolamine Binding Protein family, negatively regulates growth factor signaling by the Raf/MAP kinase pathway. Since an organic compound, locostatin, was reported to bind RKIP and inhibit cell migration by a Raf-dependent mechanism, we addressed the role of RKIP in locostatin function. Methods/Findings We analyzed locostatin interaction with RKIP and examined the biological consequences of locostatin binding on RKIP function. NMR studies show that a locostatin precursor binds to the conserved phosphatidylethanolamine binding pocket of RKIP. However, drug binding to the pocket does not prevent RKIP association with its inhibitory target, Raf-1, nor affect RKIP phosphorylation by Protein Kinase C at a regulatory site. Similarly, exposure of wild type, RKIP-depleted HeLa cells or RKIP-deficient (RKIP−/−) mouse embryonic fibroblasts (MEFs) to locostatin has no effect on MAP kinase activation. Locostatin treatment of wild type MEFs causes inhibition of cell migration following wounding. RKIP deficiency impairs migration further, indicating that RKIP protects cells against locostatin-mediated inhibition of migration. Locostatin treatment of depleted or RKIP−/− MEFs reveals cytoskeletal disruption and microtubule abnormalities in the spindle. Conclusions/Significance These results suggest that locostatin's effects on cytoskeletal structure and migration are caused through mechanisms independent of its binding to RKIP and Raf/MAP kinase signaling. The protective effect of RKIP against drug inhibition of migration suggests a new role for RKIP in potentially sequestering toxic compounds that may have deleterious effects on cells. PMID:19551145

BIOMARKERS OF PM EXPOSURE TO COMBUSTION SOURCE EMISSIONS & ORGANIC (TOXIC) COMPONENTS

EPA Science Inventory

Fine particles (PM2.5) and associated semivolatile organic compounds (SVOC) contain a very complex mixture of both organic and inorganic chemicals that may contribute to toxicity of the particles. The health effects of PM2.5 exposures in humans result from both acute and chronic...

Functional Coupling of Human Microphysiology Systems: Intestine, Liver, Kidney Proximal Tubule, Blood-Brain Barrier and Skeletal Muscle

PubMed Central

Vernetti, Lawrence; Gough, Albert; Baetz, Nicholas; Blutt, Sarah; Broughman, James R.; Brown, Jacquelyn A.; Foulke-Abel, Jennifer; Hasan, Nesrin; In, Julie; Kelly, Edward; Kovbasnjuk, Olga; Repper, Jonathan; Senutovitch, Nina; Stabb, Janet; Yeung, Catherine; Zachos, Nick C.; Donowitz, Mark; Estes, Mary; Himmelfarb, Jonathan; Truskey, George; Wikswo, John P.; Taylor, D. Lansing

2017-01-01

Organ interactions resulting from drug, metabolite or xenobiotic transport between organs are key components of human metabolism that impact therapeutic action and toxic side effects. Preclinical animal testing often fails to predict adverse outcomes arising from sequential, multi-organ metabolism of drugs and xenobiotics. Human microphysiological systems (MPS) can model these interactions and are predicted to dramatically improve the efficiency of the drug development process. In this study, five human MPS models were evaluated for functional coupling, defined as the determination of organ interactions via an in vivo-like sequential, organ-to-organ transfer of media. MPS models representing the major absorption, metabolism and clearance organs (the jejunum, liver and kidney) were evaluated, along with skeletal muscle and neurovascular models. Three compounds were evaluated for organ-specific processing: terfenadine for pharmacokinetics (PK) and toxicity; trimethylamine (TMA) as a potentially toxic microbiome metabolite; and vitamin D3. We show that the organ-specific processing of these compounds was consistent with clinical data, and discovered that trimethylamine-N-oxide (TMAO) crosses the blood-brain barrier. These studies demonstrate the potential of human MPS for multi-organ toxicity and absorption, distribution, metabolism and excretion (ADME), provide guidance for physically coupling MPS, and offer an approach to coupling MPS with distinct media and perfusion requirements. PMID:28176881

PML Nuclear Bodies

PubMed Central

Lallemand-Breitenbach, Valérie; de Thé, Hugues

2010-01-01

PML nuclear bodies are matrix-associated domains that recruit an astonishing variety of seemingly unrelated proteins. Since their discovery in the early 1960s, PML bodies have fascinated cell biologists because of their beauty and their tight association with cellular disorders. The identification of PML, a gene involved in an oncogenic chromosomal translocation, as the key organizer of these domains drew instant interest onto them. The multiple levels of PML body regulation by a specific posttranslational modification, sumoylation, have raised several unsolved issues. Functionally, PML bodies may sequester, modify or degrade partner proteins, but in many ways, PML bodies still constitute an enigma. PMID:20452955

PML nuclear bodies.

PubMed

Lallemand-Breitenbach, Valérie; de Thé, Hugues

2010-05-01

PML nuclear bodies are matrix-associated domains that recruit an astonishing variety of seemingly unrelated proteins. Since their discovery in the early 1960s, PML bodies have fascinated cell biologists because of their beauty and their tight association with cellular disorders. The identification of PML, a gene involved in an oncogenic chromosomal translocation, as the key organizer of these domains drew instant interest onto them. The multiple levels of PML body regulation by a specific posttranslational modification, sumoylation, have raised several unsolved issues. Functionally, PML bodies may sequester, modify or degrade partner proteins, but in many ways, PML bodies still constitute an enigma.

Using Toxicity Tests in Ecological Risk Assessment

EPA Pesticide Factsheets

Toxicity tests are used to expose test organisms to a medium-water, sediment, or soil-and evaluate the effects of contamination on the survival, growth, reproduction, behavior and or other attributes of these organisms.

Genetically modified Medicago truncatula lacking calcium oxalate has increased calcium bioavailability and partially rescues vitamin D receptor knockout mice phenotypes

USDA-ARS?s Scientific Manuscript database

How the distribution and sequestered form of plant macro/micro-nutrients influence their bioavailability, and ultimately impact human health, is poorly understood. The legume Medicago truncatula has a portion of its tissue calcium sequestered in the form of the calcium oxalate crystal, which reduces...

Minimum cost strategies for sequestering carbon in forests.

Treesearch

Darius M. Adams; Ralph J. Alig; Bruce A. McCarl; John M. Callaway; Steven M. Winnett

1999-01-01

This paper examines the costs of meeting explicit targets for increments of carbon sequestered in forests when both forest management decisions and the area of forests can be varied. Costs are estimated as welfare losses in markets for forest and agricultural products. Results show greatest change in management actions when targets require large near-term flux...

Meeting global policy commitments carbon sequestration and southern pine forests

Treesearch

Kurt H. Johnsen; David N. Wear; R. Oren; R.O. Teskey; Felipe Sanchez; Rodney E. Will; John Butnor; D. Markewitz; D. Richter; T. Rials; H.L. Allen; J. Seiler; D. Ellsworth; Christopher Maier; G. Katul; P.M. Dougherty

2001-01-01

In managed forests, the amount of carbon further sequestered will be determined by (1) the increased amount of carbon in standing biomass (resulting from land-use changes and increased productivity); (2) the amount of recalcitrant carbon remaining below ground at the end of rotations; and (3) the amount of carbon sequestered in products created from harvested wood....

Toxic hepatitis in occupational exposure to solvents

PubMed Central

Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

2012-01-01

The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work. PMID:22719183

Chapter 8 Tool for monitoring hydrophilic contaminants in water: polar organic chemical integrative sampler (POCIS)

USGS Publications Warehouse

Alvarez, David A.; Huckins, James N.; Petty, Jimmie D.; Jones-Lepp, Tammy L.; Stuer-Lauridsen, Frank; Getting, Dominic T.; Goddard, Jon P.; Gravell, Anthony

2007-01-01

The development of the polar organic chemical integrative sampler (POCIS) provides environmental scientists and policy makers a tool for assessing the presence and potential impacts of the hydrophilic component of these organic contaminants. The POCIS provides a means for determining the time-weighted average (TWA) concentrations of targeted chemicals that can be used in risk assessments to determine the biological impact of hydrophilic organic compounds (HpOCs) on the health of the impacted ecosystem. Field studies have shown that the POCIS has advantages over traditional sampling methods in sequestering and concentrating ultra-trace to trace levels of chemicals over time resulting in increased method sensitivity, ability to detect chemicals with a relatively short residence time or variable concentrations in the water, and simplicity in use. POCIS extracts can be tested using bioassays and can be used in organism dosing experiments for determining toxicological significance of the complex mixture of chemicals sampled. The POCIS has been successfully used worldwide under various field conditions ranging from stagnant ponds to shallow creeks to major river systems in both fresh and brackish water.

Effects of calcium, magnesium, and sodium on alleviating cadmium toxicity to Hyalella azteca

USGS Publications Warehouse

Jackson, B.P.; Lasier, P.J.; Miller, W.P.; Winger, P.V.

2000-01-01

Toxicity of trace metal ions to aquatic organisms, arising through either anthropogenic inputs or acidification of surface waters, continues to be both a regulatory and environmental problem. It is generally accepted that the free metal ion is the major toxic species (Florence et a1.,1992) and that inorganic or organic complexation renders the metal ion non-bioavailable (Meador, 1991, Galvez and Wood, 1997). However, water chemistry parameters such as alkalinity, hardness, dissolved organic carbon and pH influence metal ion toxicity either directly by lowering free metal ion concentration or indirectly through synergistic or antagonistic effects. Alkalinity and salinity can affect the speciation of metal ions by increasing ion-pair formation, thus decreasing free metal ion concentration. For example, Cu was found to be less toxic to rainbow trout in waters of high alkalinity (Miller and Mackay, 1980), due to formation of CuCO3 ion pair, and corresponding reduction in free Cu2+ concentration. The influence of salinity on the toxicity of cadmium to various organisms has been demonstrated in a number of studies (Bervoets et al., 1995, Hall et al., 1995, Lin and Dunson, 1993, Blust et al., 1992). In all these studies the apparent toxicity of cadmium was lowered as salinity was increased due to increased formation of CdC1+ and CDCl2 aqueous complexes that are non-toxic or of much lower toxicity than the free Cd2+ ion. Changes in pH exert both a biological and chemical effect on metal ion toxicity (Campbell and Stokes, 1985). Low pH favors greater metal ion solubility, and, in the absence of complexing ions, reduced speciation of the metal ion, which tends to increase toxicity compared to higher pH. However, Iow pH also enhances competition between H+ and metal ion for cell surface binding sites, which tends to decrease metal ion toxicity.

Effect of low-purity Fenton reagents on toxicity of textile dyeing effluent to Daphnia magna.

PubMed

Na, Joorim; Yoo, Jisu; Nam, Gwiwoong; Jung, Jinho

2017-09-20

This study aimed to identify the source of toxicity in textile dyeing effluent collected from February to July 2016, using Daphnia magna as a test organism. Toxicity identification evaluation (TIE) procedures were used to identify the toxicants in textile dyeing effluent, and Jar testing to simulate the Fenton process was conducted to identify the source of toxicants. Textile dyeing effluent was acutely toxic to D. magna [from 1.5 to 9.7 toxic units (TU)] during the study period. TIE results showed that Zn derived from the Fenton process was a key toxicant in textile dyeing effluent. Additionally, Jar testing revealed that low-purity Fenton reagents (FeCl 2 and FeSO 4 ), which contained large amounts of Zn (89 838 and 610 mg L -1 , respectively), were the source of toxicity. Although we were unable to conclusively identify the residual toxicity (approx. 1.4 TU of 9.71 TU) attributable to unknown toxicants in textile dyeing effluent, the findings of this study suggest that careful operation of the Fenton treatment process could contribute to eliminating its unintended toxic effects on aquatic organisms.

Acute toxicity of leachates of tire wear material to Daphnia magna--variability and toxic components.

PubMed

Wik, Anna; Dave, Göran

2006-09-01

Large amounts of tire rubber are deposited along the roads due to tread wear. Several compounds may leach from the rubber and cause toxicity to aquatic organisms. To investigate the toxic effects of tire wear material from different tires, rubber was abraded from the treads of twenty-five tires. Leachates were prepared by allowing the rubber to equilibrate with dilution water at 44 degrees C for 72 h. Then the rubber was filtered from the leachates, and test organisms (Daphnia magna) were added. Forty-eight hour EC50s ranged from 0.5 to >10.0 g l(-1). The toxicity identification evaluation (TIE) indicated that non-polar organic compounds caused most of the toxicity. UV exposure of the filtered tire leachates caused no significant increase in toxicity. However, when tested as unfiltered leachates (the rubber was not filtered from the leachates before addition of D. magna) photo-enhanced toxicity was considerable for some tires, which means that test procedures are important when testing tire leachates for aquatic (photo) toxicity. The acute toxicity of tire wear for Daphnia magna was found to be <40 times a predicted environmental concentration based on reports on the concentration of a tire component found in environmental samples, which emphasizes the need for a more extensive risk assessment of tire wear for the environment.

Investigation of Acute and Chronic Toxicity Trends of Pesticides Using High-Throughput Bioluminescence Assay Based on the Test Organism Vibrio fischeri.

PubMed

Westlund, Paul; Nasuhoglu, Deniz; Isazadeh, Siavash; Yargeau, Viviane

2018-05-01

High-throughput acute and chronic toxicity tests using Vibrio fischeri were used to assess the toxicity of a variety of fungicides, herbicides, and neonicotinoids. The use of time points beyond the traditional 30 min of an acute test highlighted the sensitivity and applicability of the chronic toxicity test and indicated that for some compounds toxicity is underestimated using only the acute test. The comparison of EC 50 values obtained from acute and chronic tests provided insight regarding the toxicity mode of action, either being direct or indirect. Using a structure-activity relationship approach similar to the one used in hazard assessments, the relationship between toxicity and key physicochemical properties of pesticides was investigated and trends were identified. This study not only provides new information regarding acute toxicity of some pesticides but also is one of the first studies to investigate the chronic toxicity of pesticides using the test organism V. fischeri. The findings demonstrated that the initial bioluminescence has a large effect on the calculated effective concentrations for target compounds in both acute and chronic tests, providing a way to improve and standardize the test protocol. In addition, the findings emphasize the need for additional investigation regarding the relationship between a toxicant's physicochemical properties and mode of action in nontarget organisms.

High-Grade Acute Organ Toxicity as a Positive Prognostic Factor in Primary Radiochemotherapy for Anal Carcinoma

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolff, Hendrik Andreas; Raus, Ismene; Jung, Klaus

Purpose: To test for a possible correlation between high-grade acute organ toxicity during primary radiochemotherapy and treatment outcome for patients with anal carcinoma. Methods and Materials: From 1991 to 2009, 72 patients with anal carcinoma were treated at our department (10 patients had stage I, 28 patients had stage II, 11 patients had stage IIIA, and 13 patients had stage IIIB cancer [Union Internationale Contre le Cancer criteria]). All patients received normofractionated (1.8 Gy/day, five times/week) whole-pelvis irradiation including iliac and inguinal lymph nodes with a cumulative dose of 50.4 Gy. Concomitant chemotherapy regimen consisted of two cycles of 5-fluorouracilmore » (1,000 mg/m{sup 2}total body surface area (TBSA)/day as continuous intravenous infusion on days 1-4 and 29-32) and mitomycin C (10 mg/m{sup 2}/TBSA, intravenously on days 1 and 29). Toxicity during treatment was monitored weekly, and any incidence of Common Toxicity Criteria (CTC) grade of {>=}3 for skin reaction, cystitis, proctitis, or enteritis was assessed as high-grade acute organ toxicity for later analysis. Results: We found significant correlation between high-grade acute organ toxicity and overall survival, locoregional control, and stoma-free survival, which was independent in multivariate analysis from other possible prognostic factors: patients with a CTC acute organ toxicity grade of {>=}3 had a 5-year overall survival rate of 97% compared to 30% in patients without (p < 0.01, multivariate analysis; 97% vs. 48%, p = 0.03 for locoregional control, and 95% vs. 59%, p = 0.05 for stoma-free survival). Conclusions: Our data indicate that normal tissue and tumor tissue may behave similarly with respect to treatment response, since high-grade acute organ toxicity during radiochemotherapy showed itself to be an independent prognostic marker in our patient population. This hypothesis should be further analyzed by using biomolecular and clinical levels in future clinical trials.« less

TOXIC ORGANIC VOLATILIZATION FROM LAND TREATMENT SYSTEMS

EPA Science Inventory

Methodology was evaluated for estimating volatilization of toxic organic chemicals from unsaturated soils. Projections were compared with laboratory data for simulated rapid infiltration wastewater treatment systems receiving primary municipal wastewater spiked with a suite of 18...

An evaluation of the residual toxicity and chemistry of a sodium hydroxide-based ballast water treatment system for freshwater ships

USGS Publications Warehouse

Elskus, Adria; Ingersoll, Christopher G.; Kemble, Nile E.; Echols, Kathy R.; Brumbaugh, William G.; Henquinet, Jeffrey; Watten, Barnaby J.

2015-01-01

Nonnative organisms in the ballast water of freshwater ships must be killed to prevent the spread of invasive species. The ideal ballast water treatment system (BWTS) would kill 100% of ballast water organisms with minimal residual toxicity to organisms in receiving waters. In the present study, the residual toxicity and chemistry of a BWTS was evaluated. Sodium hydroxide was added to elevate pH to >11.5 to kill ballast water organisms, then reduced to pH <9 by sparging with wet-scrubbed diesel exhaust (the source of CO2). Cladocerans (Ceriodaphnia dubia), amphipods (Hyalella azteca), and fathead minnows (Pimephales promelas) were exposed for 2 d to BWTS water under an air atmosphere (pH drifted to ≥9) or a 2.5% CO2 atmosphere (pH 7.5–8.2), then transferred to control water for 5 d to assess potential delayed toxicity. Chemical concentrations in the BWTS water met vessel discharge guidelines with the exception of concentrations of copper. There was little to no residual toxicity to cladocerans or fish, but the BWTS water was toxic to amphipods. Maintaining a neutral pH and diluting BWTS water by 50% eliminated toxicity to the amphipods. The toxicity of BWTS water would likely be minimal because of rapid dilution in the receiving water, with subsurface release likely preventing pH rise. This BWTS has the potential to become a viable method for treating ballast water released into freshwater systems.

Graphene oxide significantly inhibits cell growth at sublethal concentrations by causing extracellular iron deficiency.

PubMed

Yu, Qilin; Zhang, Bing; Li, Jianrong; Du, Tingting; Yi, Xiao; Li, Mingchun; Chen, Wei; Alvarez, Pedro J J

Graphene oxide (GO)-based materials are increasingly being used in medical materials and consumer products. However, their sublethal effects on biological systems are poorly understood. Here, we report that GO (at 10 to 160 mg/L) induced significant inhibitory effects on the growth of different unicellular organisms, including eukaryotes (i.e. Saccharomyces cerevisiae, Candida albicans, and Komagataella pastoris) and prokaryotes (Pseudomonas fluorescens). Growth inhibition could not be explained by commonly reported cytotoxicity mechanisms such as plasma membrane damage or oxidative stress. Based on transcriptomic analysis and measurement of extra- and intracellular iron concentrations, we show that the inhibitory effect of GO was mainly attributable to iron deficiency caused by binding to the O-functional groups of GO, which sequestered iron and disrupted iron-related physiological and metabolic processes. This inhibitory mechanism was corroborated with supplementary experiments, where adding bathophenanthroline disulfonate-an iron chelating agent-to the culture medium exerted similar inhibition, whereas removing surface O-functional groups of GO decreased iron sequestration and significantly alleviated the inhibitory effect. These findings highlight a potential indirect detrimental effect of nanomaterials (i.e. scavenging of critical nutrients), and encourage research on potential biomedical applications of GO-based materials to sequester iron and enhance treatment of iron-dependent diseases such as cancer and some pathogenic infections.

Developing nanotechnology for biofuel and plant science applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Valenstein, Justin

2012-01-01

This dissertation presents the research on the development of mesoporous silica based nanotechnology for applications in biofuels and plant science. Mesoporous silica nanoparticles (MSNs) have been the subject of great interest in the last two decades due to their unique properties of high surface area, tunable pore size and particle morphology. The robust nature of the silica framework is easily functionalized to make the MSNs a promising option for selective separations. Also, the independent channels that form the pores of MSN have been exploited in the use of particles as platforms for molecular delivery. Pore size and organic functionality aremore » varied to identify the ideal adsorbent material for free fatty acids (FFAs). The resulting material is able to sequester FFAs with a high degree of selectivity from a simulated solution and microalgal oil. The recyclability and industrial implications are also explored. A continuation of the previous material, further tuning of MSN pore size was investigated. Particles with a smaller diameter selectively sequester polyunsaturated free fatty acids (PUFAs) over monounsaturated FFAs and saturated FFAs. The experimental results were verified with molecular modeling. Mesoporous silica nanoparticle materials with a pore diameter of 10 nm (MSN-10) were decorated with small gold nanoparticles. The resulting materials were shown to deliver proteins and DNA into plant cells using the biolistic method.« less

Temporal and Spatial Dynamics of Carbon Storage in California Coastal Salt Marshes

NASA Astrophysics Data System (ADS)

Brown, L. N.; MacDonald, G. M.

2016-12-01

Coastal salt marshes rank as one of the ecosystems which sequester the most carbon (C) in the world (Chmura, 2003; Mcleod et al., 2011). California hosts multiple small marsh ecosystems outside of the San Francisco Bay that are limited in geographic extent but still contribute significantly to global soil C. We have collected over 100 sediment cores from 11 coastal marsh sites from Humboldt Bay to Tijuana River Estuary on the coast of California. Our 100 cm depth cores cover high, mid, and low elevations in the coastal salt marsh ecosystem, which are known to sequester carbon with varying rates. Approximately 40 cores of the 100 collected cores have been selected for detailed chronologic and stratigraphic analysis, 3 cores at each site minimum. Chronologies are established using 14C, 137Cs, and 210Pb. Our study estimates a carbon sequestration rate of 49 g C m-2 yr-1 for California over the past 100 years. These results are consistent with other long term estimates of soil C, which generally are lower because of natural decomposition of organic C, but also reinforces long-term persistence of soil C in salt marshes over time. These estimates provide valuable proof of the long-term capacity and spatial variability of C sequestration in coastal salt marshes of California.

Assessment of acrylamide toxicity using a battery of standardised bioassays.

PubMed

Zovko, Mira; Vidaković-Cifrek, Željka; Cvetković, Želimira; Bošnir, Jasna; Šikić, Sandra

2015-12-01

Acrylamide is a monomer widely used as an intermediate in the production of organic chemicals, e.g. polyacrylamides (PAMs). Since PAMs are low cost chemicals with applications in various industries and waste- and drinking water treatment, a certain amount of non-polymerised acrylamide is expected to end up in waterways. PAMs are non-toxic but acrylamide induces neurotoxic effects in humans and genotoxic, reproductive, and carcinogenic effects in laboratory animals. In order to evaluate the effect of acrylamide on freshwater organisms, bioassays were conducted on four species: algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata, duckweed Lemna minor and water flea Daphnia magna according to ISO (International Organization for Standardisation) standardised methods. This approach ensures the evaluation of acrylamide toxicity on organisms with different levels of organisation and the comparability of results, and it examines the value of using a battery of low-cost standardised bioassays in the monitoring of pollution and contamination of aquatic ecosystems. These results showed that EC50 values were lower for Desmodesmus subspicatus and Pseudokirchneriella subcapitata than for Daphnia magna and Lemna minor, which suggests an increased sensitivity of algae to acrylamide. According to the toxic unit approach, the values estimated by the Lemna minor and Daphnia magna bioassays, classify acrylamide as slightly toxic (TU=0-1; Class 1). The results obtained from algal bioassays (Desmodesmus subspicatus and Pseudokirchneriella subcapitata) revealed the toxic effect of acrylamide (TU=1-10; Class 2) on these organisms.

Reimagining Carbon Sequestration in Fluviodeltaic Systems: Contributions from Clastic Overbank Deposits versus Peat

NASA Astrophysics Data System (ADS)

Jankowski, K. L.; Shen, Z.; Tornqvist, T. E.; Steponaitis, E.; Rosenheim, B. E.

2017-12-01

Understanding how natural systems sequester carbon, and at what rates, is critical for planning future climate change mitigation strategies. For the decade from 2006-2015, average annual CO2 emissions to the atmosphere ( 11 Pg C) are not completely offset by atmospheric retention and oceanic uptake ( 5 Pg C and 2.5 Pg C, respectively) (LeQuéré et al., 2016) implying residual terrestrial C sinks that are not fully understood. Rivers are increasingly recognized as playing a complex role in the global C cycle which, beyond acting as a source of CO2to the atmosphere, may act as a C sink. Here, we find that the mechanisms of C transfer through fluviodeltaic systems include various means of C storage and contribute significantly to the global unidentified terrestrial C sink. C sequestration by coastal wetlands - at a globally averaged rate of 200 g C/m2/yr - has been widely recognized as an important mechanism for terrestrial C sequestration, with less attention paid to the role of inland fluvial to deltaic deposition. We sampled three cores in the central Mississippi Delta for C content (using elemental analysis) and bulk density in fluviodeltaic overbank deposits as well as intercalated peat. We also established a flexible, Bayesian age-depth model using Bacon (Blaauw and Christen 2011) in order to calculate sediment accumulation rates from 14C and OSL ages. Peat deposits sequester C at an average rate of 40 g C/m2/yr. The relatively organic-poor overbank sediments sequester C at an average rate of 200 g C/m2/yr including what are likely punctuated periods of very fast deposition. While the episodic nature of overbank deposits make quantifying an annual impact difficult, it is clear that overbank deposition is an important and efficient mechanism for C sequestration in fluviodeltaic systems that deserves continued investigation.

Soil carbon stocks in Sarawak, Malaysia.

PubMed

Padmanabhan, E; Eswaran, H; Reich, P F

2013-11-01

The relationship between greenhouse gas emission and climate change has led to research to identify and manage the natural sources and sinks of the gases. CO2, CH4, and N2O have an anthropic source and of these CO2 is the least effective in trapping long wave radiation. Soil carbon sequestration can best be described as a process of removing carbon dioxide from the atmosphere and relocating into soils in a form that is not readily released back into the atmosphere. The purpose of this study is to estimate carbon stocks available under current conditions in Sarawak, Malaysia. SOC estimates are made for a standard depth of 100 cm unless the soil by definition is less than this depth, as in the case of lithic subgroups. Among the mineral soils, Inceptisols tend to generally have the highest carbon contents (about 25 kg m(-2) m(-1)), while Oxisols and Ultisols rate second (about 10-15 kg m(-2) m(-1)). The Oxisols store a good amount of carbon because of an appreciable time-frame to sequester carbon and possibly lower decomposition rates for the organic carbon that is found at 1m depths. Wet soils such as peatlands tend to store significant amounts of carbon. The highest values estimated for such soils are about 114 kg m(-2) m(-1). Such appreciable amounts can also be found in the Aquepts. In conclusion, it is pertinent to recognize that degradation of the carbon pool, just like desertification, is a real process and that this irreversible process must be addressed immediately. Therefore, appropriate soil management practices should be instituted to sequester large masses of soil carbon on an annual basis. This knowledge can be used effectively to formulate strategies to prevent forest fires and clearing: two processes that can quickly release sequestered carbon to the atmosphere in an almost irreversible manner. Copyright © 2013 Elsevier B.V. All rights reserved.

The relationship between metal toxicity and biotic ligand binding affinities in aquatic and soil organisms: a review.

PubMed

Ardestani, Masoud M; van Straalen, Nico M; van Gestel, Cornelis A M

2014-12-01

The biotic ligand model (BLM) is a theoretical, potentially mechanistic approach to assess metal bioavailability in soil and aquatic systems. In a BLM, toxicity is linked to the fraction of biotic ligand occupied, which in turn, depends on the various components of the solution, including activity of the metal. Bioavailability is a key factor in determining toxicity and uptake of metals in organisms. In this study, the present status of BLM development for soil and aquatic organisms is summarized. For all species and all metals, toxicity was correlated with the conditional biotic ligand binding constants. For almost all organisms, values for Ag, Cu, and Cd were higher than those for Zn and Ni. The constants derived for aquatic systems seem to be equally valid for soil organisms, but in the case of soils, bioavailability from the soil solution is greatly influenced by the presence of the soil solid phase. Copyright © 2014 Elsevier Ltd. All rights reserved.

Acute lethal toxicity of environmental pollutants to aquatic organisms.

PubMed

Yen, Jui-Hung; Lin, Kuo-Hsiung; Wang, Yei-Shung

2002-06-01

The acute lethal toxicity of environment pollutants including chlorophenol, haloalkane, quinone, and substituted nitrobenzene (i.e., nitrophenol, nitrobenzene, nitrotoluene, and aniline) compounds to aquatic organisms was determined. Determination of toxicity of chemicals was performed with chlorella, daphnia, carp, and tilapia. The toxicity of chlorophenols had no relation to the number of chlorine atoms on the benzene ring, but monochlorophenol had lower activity than more chlorine-substituted compounds. The tolerance levels of daphnia and carp to haloalkanes was found to be higher than that of chlorella; toxicity to chlorella was several hundred times higher than to daphnia. The toxicity of naphthoquinone compounds to chlorella and carp was higher than that of anthraquinone. A compound with a monochloride substitution on anthraquinone ring was less toxic to carp than those substituted with amine, hydroxyl, and dichlorine groups. Nitrobenzene compounds with an additional substitution group on the p position were extremely toxic to daphnia and carp. (c) 2002 Elsevier Science (USA).

Applicability of ambient toxicity testing to national or regional water-quality assessment

USGS Publications Warehouse

Elder, John F.

1990-01-01

Comprehensive assessment of the quality of natural waters requires a multifaceted approach. Descriptions of existing conditions may be achieved by various kinds of chemical and hydrologic analyses, whereas information about the effects of such conditions on living organisms depends on biological monitoring. Toxicity testing is one type of biological monitoring that can be used to identify possible effects of toxic contaminants. Based on experimentation designed to monitor responses of organisms to environmental stresses, toxicity testing may have diverse purposes in water-quality assessments. These purposes may include identification of areas that warrant further study because of poor water quality or unusual ecological features, verification of other types of monitoring, or assessment of contaminant effects on aquatic communities. Toxicity-test results are most effective when used as a complement to chemical analyses, hydrologic measurements, and other biological monitoring. However, all toxicity-testing procedures have certain limitations that must be considered in developing the methodology and applications of toxicity testing in any large-scale water-quality-assessment program. A wide variety of toxicity-test methods have been developed to fulfill the needs of diverse applications. The methods differ primarily in the selections made relative to four characteristics: (1) test species, (2) endpoint (acute or chronic), (3) test-enclosure type, and (4) test substance (toxicant) that functions as the environmental stress. Toxicity-test approaches vary in their capacity to meet the needs of large-scale assessments of existing water quality. Ambient testing, whereby the test organism is exposed to naturally occurring substances that contain toxicant mixtures in an organic or inorganic matrix, is more likely to meet these needs than are procedures that call for exposure of the test organisms to known concentrations of a single toxicant. However, meaningful interpretation of ambient test results depends on the existence of accompanying chemical analysis of the ambient media. The ambient test substance may be water or sediments. Sediment tests have had limited application, but they are useful because most toxicants tend to accumulate in sediments and many test species either inhabit the sediments or are in frequent contact with them. Biochemical testing methods, which have been developing rapidly in recent years, are likely to be among the most useful procedures for large-scale water-quality assessments. They are relatively rapid and simple, and more. importantly, they focus on biochemical changes that are the initial responses of virtually all organisms to environmental stimuli. Most species are sensitive to relatively few toxicants, and their sensitivities vary as conditions change. Therefore, each test method has particular uses and limitations, and no single test has universal applicability. One of the most informative approaches to toxicity testing is to combine biochemical tests with other test methods in a 'battery of tests' that is diversified enough to characterize different types of toxicants and different trophic levels. However, such an approach can be costly, and if not carefully designed, it may not yield enough additional information to warrant the additional cost. The application of toxicity tests to large-scale water-quality assessments is hampered by a number of difficulties. Toxicity tests often are not sensitive enough to enable detection of most contaminant problems in the natural environment. Furthermore, because sensitivities among different species and test conditions can be highly variable, conclusions about the toxicant problems of an ecosystem are strongly dependent on the test procedure used. In addition, the experimental systems used in toxicity tests cannot replicate the complexity or variability of natural conditions, and positive test results cannot identify the source or nature of

[Assessment of the relationship of properties of chemical compounds and their toxicity to a unified hygienic standardization for chemicals].

PubMed

Trushkov, V F; Perminov, K A; Sapozhnikova, V V; Ignatova, O L

2013-01-01

The connection of thermodynamic properties and parameters of toxicity of chemical substances was determined. Obtained data are used for the evaluation of toxicity and hygienic rate setting of chemical compounds. The relationship between enthalpy and toxicity of chemical compounds has been established. Orthogonal planning of the experiment was carried out in the course of the investigations. Equation of unified hygienic rate setting in combined, complex, conjunct influence on the organism is presented. Prospects of determination of toxicity and methodology of unified hygienic rate setting in combined, complex, conjunct influence on the organism are presented

Differential Regulation of Angiogenesis using Degradable VEGF-Binding Microspheres

PubMed Central

Belair, David G.; Miller, Michael J.; Wang, Shoujian; Darjatmokon, Soesiawati R.; Binder, Bernard Y.K.; Sheibani, Nader; Murphy, William L.

2016-01-01

Vascular endothelial growth factor (VEGF) spatial and temporal activity must be tightly controlled during angiogenesis to form perfusable vasculature in a healing wound. The native extracellular matrix (ECM) regulates growth factor activity locally via sequestering, and researchers have used ECM-mimicking approaches to regulate the activity of VEGF in cell culture and in vivo. However, the impact of dynamic, affinity-mediated growth factor sequestering has not been explored in detail with biomaterials. Here, we sought to modulate VEGF activity dynamically over time using poly(ethylene glycol) microspheres containing VEGF-binding peptides (VBPs) and exhibiting varying degradation rates. The degradation rate of VBP microspheres conferred a differential ability to up- or down-regulate VEGF activity in culture with primary human endothelial cells. VBP microspheres with fast-degrading crosslinks reduced VEGF activity and signaling, while VBP microspheres with no inherent degradability sequestered and promoted VEGF activity in culture with endothelial cells. VBP microspheres with degradable crosslinks significantly reduced neovascularization in vivo, but neither non-degradable VBP microspheres nor bolus delivery of soluble VBP reduced neovascularization. The covalent incorporation of VBP to degradable microspheres was required to reduce neovascularization in a mouse model of choroidal neovascularization in vivo, which demonstrates a potential clinical application of degradable VBP microspheres to reduce pathological angiogenesis. The results herein highlight the ability to modulate the activity of a sequestered growth factor by changing the crosslinker identity within PEG hydrogel microspheres. The insights gained here may instruct the design and translation of affinity-based growth factor sequestering biomaterials for regenerative medicine applications. PMID:27061268

JV Task 77 - Health Implications of Mercury - Selenium Interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicholas Ralstion; Laura Raymond

2007-12-15

Exposure to mercury (Hg) commonly results from eating fish containing bioaccumulated methylmercury (MeHg). However, conflicting observations and conclusions have arisen from the ongoing human studies of MeHg exposure from fish consumption. Resolving these uncertainties has important implications for human health since significant nutritional benefits will be lost if fish consumption is needlessly avoided. Selenium (Se), an important nutrient that is abundant in ocean fish, has a potent protective effect against Hg toxicity. This protective effect was thought to be due to the high binding affinities between Hg and Se resulting in Se sequestration of Hg to prevent its harmful effects.more » However, it is imperative to consider the opposing effect of Hg on Se physiology. Crucial proteins that require Se normally protect the brain and hormone-producing glands from oxidative damage. MeHg is able to cross all biological barriers and enter cells in these tissues, where its high Se affinity results in Se sequestration. Sequestration in association with Hg prevents Se from participating in proteins that perform essential antioxidant activities. Supplemental dietary Se is able to replace Se sequestered by Hg and maintain normal antioxidant protection of brain and glands. The goal of this research project was to assess the potency of normal dietary levels of Se in protection against MeHg toxicity. Results from this project indicate that MeHg toxicity is only evident in situations resulting in Hg occurring in high molar excess of Se. Additionally, the common method of MeHg risk assessments using measurements of toenail and blood levels of Hg was shown to provide an accurate reflection of Hg exposure but did not accurately indicate risk of toxicity resulting from that exposure. Instead, Hg:Se molar ratios are proposed as a superior means of assessing risks associated with MeHg exposure.« less

Mathematical Models Relating Effects of Xenobiotic Substances on Individuals and Populations

DTIC Science & Technology

1997-09-30

experimental information quantifying the impact of toxicants on the individual organisms within impacted, or potentially impacted populations. OBJECTIVES...The research has two main parts: (i) modeling the consequences for individuals of toxicant -induced changes in the rates of energy acquisition and...In modeling the response of individuals to toxicants , we use dynamic energy budget (DEB) models to describe the rules by which individual organisms

Evaluating the aquatic toxicity of complex organic chemical mixtures: lessons learned from polycyclic aromatic hydrocarbon and petroleum hydrocarbon case studies.

PubMed

Landrum, Peter F; Chapman, Peter M; Neff, Jerry; Page, David S

2012-04-01

Experimental designs for evaluating complex mixture toxicity in aquatic environments can be highly variable and, if not appropriate, can produce and have produced data that are difficult or impossible to interpret accurately. We build on and synthesize recent critical reviews of mixture toxicity using lessons learned from 4 case studies, ranging from binary to more complex mixtures of primarily polycyclic aromatic hydrocarbons and petroleum hydrocarbons, to provide guidance for evaluating the aquatic toxicity of complex mixtures of organic chemicals. Two fundamental requirements include establishing a dose-response relationship and determining the causative agent (or agents) of any observed toxicity. Meeting these 2 requirements involves ensuring appropriate exposure conditions and measurement endpoints, considering modifying factors (e.g., test conditions, test organism life stages and feeding behavior, chemical transformations, mixture dilutions, sorbing phases), and correctly interpreting dose-response relationships. Specific recommendations are provided. Copyright © 2011 SETAC.

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

NASA Astrophysics Data System (ADS)

Audry, S.; Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Dupré, B.

2011-11-01

This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m-2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions was suggested. This shift was likely promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

Organic matter mineralization and trace element post-depositional redistribution in Western Siberia thermokarst lake sediments

NASA Astrophysics Data System (ADS)

Audry, S.; Pokrovsky, O. S.; Shirokova, L. S.; Kirpotin, S. N.; Dupré, B.

2011-08-01

This study reports the very first results on high-resolution sampling of sediments and their porewaters from three thermokarst (thaw) lakes representing different stages of ecosystem development located within the Nadym-Pur interfluve of the Western Siberia plain. Up to present time, the lake sediments of this and other permafrost-affected regions remain unexplored regarding their biogeochemical behavior. The aim of this study was to (i) document the early diagenesic processes in order to assess their impact on the organic carbon stored in the underlying permafrost, and (ii) characterize the post-depositional redistribution of trace elements and their impact on the water column. The estimated organic carbon (OC) stock in thermokarst lake sediments of 14 ± 2 kg m-2 is low compared to that reported for peat soils from the same region and denotes intense organic matter (OM) mineralization. Mineralization of OM in the thermokarst lake sediments proceeds under anoxic conditions in all the three lakes. In the course of the lake development, a shift in mineralization pathways was evidenced from nitrate and sulfate to Fe- and Mn-oxyhydroxides as the main terminal electron acceptors in the early diagenetic reactions. This shift was promoted by the diagenetic consumption of nitrate and sulfate and their gradual depletion in the water column due to progressively decreasing frozen peat lixiviation occurring at the lake's borders. Trace elements were mobilized from host phases (OM and Fe- and Mn-oxyhydroxides) and partly sequestered in the sediment in the form of authigenic Fe-sulfides. Arsenic and Sb cycling was also closely linked to that of OM and Fe- and Mn-oxyhydroxides. Shallow diagenetic enrichment of particulate Sb was observed in the less mature stages. As a result of authigenic sulfide precipitation, the sediments of the early stage of ecosystem development were a sink for water column Cu, Zn, Cd, Pb and Sb. In contrast, at all stages of ecosystem development, the sediments were a source of dissolved Co, Ni and As to the water column. However, the concentrations of these trace elements remained low in the bottom waters, indicating that sorption processes on Fe-bounding particles and/or large-size organo-mineral colloids could mitigate the impact of post-depositional redistribution of toxic elements on the water column.

Phenols, flame retardants and phthalates in water and wastewater - a global problem.

PubMed

Ayanda, Olushola Sunday; Olutona, Godwin Oladele; Olumayede, Emmanuel G; Akintayo, Cecilia O; Ximba, Bhekumusa J

Organic pollutants in water and wastewater have been causing serious environmental problems. The arbitrary discharge of wastewater by industries, and handling, use, and disposal constitute a means by which phenols, flame retardants (FRs), phthalates (PAEs) and other toxic organic pollutants enter the ecosystem. Moreover, these organic pollutants are not completely removed during treatment processes and might be degraded into highly toxic derivatives, which has led to their occurrence in the environment. Phenols, FRs and PAEs are thus highly toxic, carcinogenic and mutagenic, and are capable of disrupting the endocrine system. Therefore, investigation to understand the sources, pathways, behavior, toxicity and exposure to phenols, FRs and PAEs in the environment is necessary. Formation of different by-products makes it difficult to compare the efficacy of the treatment processes, most especially when other organic matters are present. Hence, high levels of phenols, FRs and PAEs removal could be attained with in-line combined treatment processes.

Carbon sequestration in forests as a national policy issue

Treesearch

Linda S. Heath; Linda A. Joyce

1997-01-01

The United States' 1993 Climate Change Action Plan called upon the forestry sector to sequester an additional 10 million metric tons/yr by the year 2000. Forests are currently sequestering carbon and may provide opportunities to mitigate fossil fuel emissions in the near-term until fossil fuel emissions can be reduced. Using the analysis of carbon budgets based on...

Forest carbon benefits, costs and leakage effects of carbon reserve scenarios in the United States

Treesearch

Prakash Nepal; Peter J. Ince; Kenneth E. Skog; Sun J. Chang

2013-01-01

This study evaluated the potential effectiveness of future carbon reserve scenarios, where U.S. forest landowners would hypothetically be paid to sequester carbon on their timberland and forego timber harvests for 100 years. Scenarios featured direct payments to landowners of $0 (baseline), $5, $10, or $15 per metric ton of additional forest carbon sequestered on the...

Aligning ecology and markets in the forest carbon cycle

Treesearch

Matthew D. Hurteau; Bruce A. Hungate; George W. Koch; Malcolm P. North; Gordon R Smith

2013-01-01

A forest carbon (C) offset is a quantifiable unit of C that is commonly developed at the local or regional project scale and is designed to counterbalance anthropogenic C emissions by sequestering C in trees. In capand- trade programs, forest offsets have market value if the sequestered C is additional (more than would have occurred in the absence of the project) and...

Elution of uranium and transition metals from amidoxime-based polymer adsorbents for sequestering uranium from seawater

DOE PAGES

Pan, Horng-Bin; Kuo, Li-Jung; Miyamoto, Naomi; ...

2015-11-30

High-surface-area amidoxime and carboxylic acid grafted polymer adsorbents developed at Oak Ridge National Laboratory were tested for sequestering uranium in a flowing seawater flume system at the PNNL-Marine Sciences Laboratory. FTIR spectra indicate that a KOH conditioning process is necessary to remove the proton from the carboxylic acid and make the sorbent effective for sequestering uranium from seawater. The alkaline conditioning process also converts the amidoxime groups to carboxylate groups in the adsorbent. Both Na 2CO 3 H 2O 2 and hydrochloric acid elution methods can remove ~95% of the uranium sequestered by the adsorbent after 42 days of exposuremore » in real seawater. The Na 2CO 3 H 2O 2 elution method is more selective for uranium than conventional acid elution. Iron and vanadium are the two major transition metals competing with uranium for adsorption to the amidoxime-based adsorbents in real seawater. Tiron (4,5-Dihydroxy-1,3-benzenedisulfonic acid disodium salt, 1 M) can remove iron from the adsorbent very effectively at pH around 7. The coordination between vanadium (V) and amidoxime is also discussed based on our 51V NMR data.« less

Effects of triclosan on marine benthic and epibenthic organisms.

PubMed

Perron, Monique M; Ho, Kay T; Cantwell, Mark G; Burgess, Robert M; Pelletier, Marguerite C

2012-08-01

Triclosan is an antimicrobial compound that has been widely used in consumer products such as toothpaste, deodorant, and shampoo. Because of its widespread use, triclosan has been detected in various environmental media, including wastewater, sewage sludge, surface waters, and sediments. Triclosan is acutely toxic to numerous aquatic organisms, but very few studies have been performed on estuarine and marine benthic organisms. For whole sediment toxicity tests, the sediment-dwelling estuarine amphipod, Ampelisca abdita, and the epibenthic mysid shrimp, Americamysis bahia, are commonly used organisms. In the present study, median lethal concentration values (LC50) were obtained for both of these organisms using water-only and whole sediment exposures. Acute 96-h water-only toxicity tests resulted in LC50 values of 73.4 and 74.3 µg/L for the amphipod and mysid, respectively. For the 7-d whole sediment toxicity test, LC50 values were 303 and 257 mg/kg (dry wt) for the amphipod and mysid, respectively. Using equilibrium partitioning theory, these whole sediment values are equivalent to interstitial water LC50 values of 230 and 190 µg/L for the amphipod and mysid, respectively, which are within a threefold difference of the observed 96-h LC50 water-only values. Triclosan was found to accumulate in polychaete tissue in a 28-d bioaccumulation study with a biota-sediment accumulation factor of 0.23 kg organic carbon/kg lipid. These data provide some of the first toxicity data for triclosan with marine benthic and epibenthic species while also indicating a need to better understand the effects of other forms of sediment carbon, triclosan ionization, and organism metabolism of triclosan on the chemical's behavior and toxicity in the aquatic environment. Copyright © 2012 SETAC.

Accuracy of Chronic Aquatic Toxicity Estimates Determined from Acute Toxicity Data and Two Time–Response Models.

EPA Science Inventory

Traditionally, chronic toxicity in aquatic organisms and wildlife has been determined from either toxicity test data, acute to chronic ratios, or application of safety factors. A more recent alternative approach has been to estimate chronic toxicity by modeling the time course of...

Final Recommendations of the Air Toxics Work Group

EPA Pesticide Factsheets

The Air Toxics Workgroup was organized under the Clean Air Act Advisory Committee for the purpose of discussing and identifying recommendations related to Urban Air Toxics. The workgroup is part of the Permits, New Source Review and Toxics Subcommittee.

Human APC sequesters beta-catenin even in the absence of GSK-3beta in a Drosophila model.

PubMed

Rao, P R; Makhijani, K; Shashidhara, L S

2008-04-10

There have been conflicting reports on the requirement of GSK-3beta-mediated phosphorylation of the tumor suppressor adenomatous polyposis coli (APC) vis-à-vis its ability to bind and degrade beta-catenin. Using a unique combination of loss of function for Shaggy/GSK-3beta and a gain of function for human APC in Drosophila, we show that misexpressed human APC (hAPC) can still sequester Armadillo/beta-catenin. In addition, human APC could suppress gain of Wnt/Wingless phenotypes associated with loss of Shaggy/GSK-3beta activity, suggesting that sequestered Armadillo/beta-catenin is non-functional. Based on these studies, we propose that binding per se of beta-catenin by APC does not require phosphorylation by GSK-3beta.

Nutrient sequestration in Aquitaine lakes (SW France) limits nutrient flux to the coastal zone

NASA Astrophysics Data System (ADS)

Buquet, Damien; Anschutz, Pierre; Charbonnier, Céline; Rapin, Anne; Sinays, Rémy; Canredon, Axel; Bujan, Stéphane; Poirier, Dominique

2017-12-01

Oligotrophic coastal zones are disappearing from increased nutrient loading. The quantity of nutrients reaching the coast is determined not only by their original source (e.g. fertilizers used in agriculture, waste water discharges) and the land use, but also by the pathways through which nutrients are cycled from the source to the river mouth. In particular, lakes sequester nutrients and, hence, reduce downstream transfer of nutrients to coastal environments. Here, we quantify the impact of Aquitaine great lakes on the fluxes of dissolved macro-nutrients (N, P, Si) to the Bay of Biscay. For that, we have measured nutrient concentrations and fluxes in 2014 upstream and downstream lakes of Lacanau and Carcans-Hourtin, which belongs to the catchment of the Arcachon Bay, which is the largest coastal lagoon of the Bay of Biscay French coast. Data were compared to values obtained from the Leyre river, the main freshwater and nutrient source for the lagoon. Results show that processes in lakes greatly limit nutrient flux to the lagoon compared to fluxes from Leyre river, although the watershed is similar in terms of land cover. In lakes, phosphorus and silicon are trapped for long term in the sediment, silicon as amorphous biogenic silica and phosphorus as organic P and P associated with Fe-oxides. Nitrogen that enters lakes mostly as nitrate is used for primary production. N is mineralized in the sediment; a fraction diffuses as ammonium. N2 production through benthic denitrification extracts only 10% of dissolved inorganic nitrogen from the aquatic system. The main part is sequestered in organic-rich sediment that accumulates below 5 m depth in both lakes.

Block Copolymer Micelles as Nanocontainers for Controlled Release of Proteins from Biocompatible Oil Phases

PubMed Central

2009-01-01

Biocompatible oils are used in a variety of medical applications ranging from vaccine adjuvants to vehicles for oral drug delivery. To enable such nonpolar organic phases to serve as reservoirs for delivery of hydrophilic compounds, we explored the ability of block copolymer micelles in organic solvents to sequester proteins for sustained release across an oil−water interface. Self-assembly of the block copolymer, poly(ϵ-caprolactone)-block-poly(2-vinyl pyridine) (PCL-b-P2VP), was investigated in toluene and oleic acid, a biocompatible naturally occurring fatty acid. Micelle formation in toluene was characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) imaging of micelles cast onto silicon substrates. Cryogenic transmission electron microscopy confirmed a spherical morphology in oleic acid. Studies of homopolymer solubility implied that micelles in oleic acid consist of a P2VP corona and a PCL core, while P2VP formed the core of micelles assembled in toluene. The loading of two model proteins (ovalbumin (ova) and bovine serum albumin (BSA)) into micelles was demonstrated with loadings as high as 7.8% wt of protein per wt of P2VP in oleic acid. Characterization of block copolymer morphology in the two solvents after protein loading revealed spherical particles with similar size distributions to the as-assembled micelles. Release of ova from micelles in oleic acid was sustained for 12−30 h upon placing the oil phase in contact with an aqueous bath. Unique to the situation of micelle assembly in an oily phase, the data suggest protein is sequestered in the P2VP corona block of PCL-b-P2VP micelles in oleic acid. More conventionally, protein loading occurs in the P2VP core of micelles assembled in toluene. PMID:19235932

Emergence of the acute-phase protein hemopexin in jawed vertebrates.

PubMed

Dooley, Helen; Buckingham, E Bryan; Criscitiello, Michael F; Flajnik, Martin F

2010-01-01

When released from damaged erythrocytes free heme not only provides a source of iron for invading bacteria but also highly toxic due to its ability to catalyze free radical formation. Hemopexin (Hx) binds free heme with very high-affinity and thus protects against heme toxicity, sequesters heme from pathogens, and helps conserve valuable iron. Hx is also an acute-phase serum protein (APP), whose expression is induced by inflammation. To date Hx has been identified as far back in phylogeny as bony fish where it is called warm-temperature acclimation-related 65 kDa protein (WAP65), as serum protein levels are increased at elevated environmental temperatures as well as by infection. During analysis of nurse shark (Ginglymostoma cirratum) plasma we isolated a Ni(2+)-binding serum glycoprotein and characterized it as the APP Hx. We subsequently cloned Hx from nurse shark and another cartilaginous fish species, the little skate Leucoraja erinacea. Functional analysis showed shark Hx, like that of mammals, binds heme but is found at unusually high levels in normal shark serum. As an Hx orthologue could not be found in the genomes of jawless vertebrates or lower deuterostomes it appears to have arisen just prior to the emergence of jawed vertebrates, coincident with the second round of genome-wide duplication and the appearance of tetrameric hemoglobin (Hb). Copyright © 2010 Elsevier Ltd. All rights reserved.

Silver nanoparticles reduce brain inflammation and related neurotoxicity through induction of H2S-synthesizing enzymes

NASA Astrophysics Data System (ADS)

Gonzalez-Carter, Daniel A.; Leo, Bey Fen; Ruenraroengsak, Pakatip; Chen, Shu; Goode, Angela E.; Theodorou, Ioannis G.; Chung, Kian Fan; Carzaniga, Raffaella; Shaffer, Milo S. P.; Dexter, David T.; Ryan, Mary P.; Porter, Alexandra E.

2017-03-01

Silver nanoparticles (AgNP) are known to penetrate into the brain and cause neuronal death. However, there is a paucity in studies examining the effect of AgNP on the resident immune cells of the brain, microglia. Given microglia are implicated in neurodegenerative disorders such as Parkinson’s disease (PD), it is important to examine how AgNPs affect microglial inflammation to fully assess AgNP neurotoxicity. In addition, understanding AgNP processing by microglia will allow better prediction of their long term bioreactivity. In the present study, the in vitro uptake and intracellular transformation of citrate-capped AgNPs by microglia, as well as their effects on microglial inflammation and related neurotoxicity were examined. Analytical microscopy demonstrated internalization and dissolution of AgNPs within microglia and formation of non-reactive silver sulphide (Ag2S) on the surface of AgNPs. Furthermore, AgNP-treatment up-regulated microglial expression of the hydrogen sulphide (H2S)-synthesizing enzyme cystathionine-γ-lyase (CSE). In addition, AgNPs showed significant anti-inflammatory effects, reducing lipopolysaccharide (LPS)-stimulated ROS, nitric oxide and TNFα production, which translated into reduced microglial toxicity towards dopaminergic neurons. Hence, the present results indicate that intracellular Ag2S formation, resulting from CSE-mediated H2S production in microglia, sequesters Ag+ ions released from AgNPs, significantly limiting their toxicity, concomitantly reducing microglial inflammation and related neurotoxicity.

Reciprocal Efficiency of RNQ1 and Polyglutamine Detoxification in the Cytosol and Nucleus

PubMed Central

Douglas, Peter M.; Summers, Daniel W.; Ren, Hong-Yu

2009-01-01

Onset of proteotoxicity is linked to change in the subcellular location of proteins that cause misfolding diseases. Yet, factors that drive changes in disease protein localization and the impact of residence in new surroundings on proteotoxicity are not entirely clear. To address these issues, we examined aspects of proteotoxicity caused by Rnq1-green fluorescent protein (GFP) and a huntingtin's protein exon-1 fragment with an expanded polyglutamine tract (Htt-103Q), which is dependent upon the intracellular presence of [RNQ+] prions. Increasing heat-shock protein 40 chaperone activity before Rnq1-GFP expression, shifted Rnq1-GFP aggregation from the cytosol to the nucleus. Assembly of Rnq1-GFP into benign amyloid-like aggregates was more efficient in the nucleus than cytosol and nuclear accumulation of Rnq1-GFP correlated with reduced toxicity. [RNQ+] prions were found to form stable complexes with Htt-103Q, and nuclear Rnq1-GFP aggregates were capable of sequestering Htt-103Q in the nucleus. On accumulation in the nucleus, conversion of Htt-103Q into SDS-resistant aggregates was dramatically reduced and Htt-103Q toxicity was exacerbated. Alterations in activity of molecular chaperones, the localization of intracellular interaction partners, or both can impact the cellular location of disease proteins. This, in turn, impacts proteotoxicity because the assembly of proteins to a benign state occurs with different efficiencies in the cytosol and nucleus. PMID:19656852

Comparative venomics of Psyttalia lounsburyi and P. concolor, two olive fruit fly parasitoids: a hypothetical role for a GH1 β-glucosidase

PubMed Central

Mathé-Hubert, Hugo; Colinet, Dominique; Deleury, Emeline; Belghazi, Maya; Ravallec, Marc; Poulain, Julie; Dossat, Carole; Poirié, Marylène; Gatti, Jean-Luc

2016-01-01

Venom composition of parasitoid wasps attracts increasing interest – notably molecules ensuring parasitism success on arthropod pests – but its variation within and among taxa is not yet understood. We have identified here the main venom proteins of two braconid wasps, Psyttalia lounsburyi (two strains from South Africa and Kenya) and P. concolor, olive fruit fly parasitoids that differ in host range. Among the shared abundant proteins, we found a GH1 β-glucosidase and a family of leucine-rich repeat (LRR) proteins. Olive is extremely rich in glycoside compounds that are hydrolyzed by β-glucosidases into defensive toxic products in response to phytophagous insect attacks. Assuming that Psyttalia host larvae sequester ingested glycosides, the injected venom GH1 β-glucosidase could induce the release of toxic compounds, thus participating in parasitism success by weakening the host. Venom LRR proteins are similar to truncated Toll-like receptors and may possibly scavenge the host immunity. The abundance of one of these LRR proteins in the venom of only one of the two P. lounsburyi strains evidences intraspecific variation in venom composition. Altogether, venom intra- and inter-specific variation in Psyttalia spp. were much lower than previously reported in the Leptopilina genus (Figitidae), suggesting it might depend upon the parasitoid taxa. PMID:27779241

Three-way interaction among plants, bacteria, and coleopteran insects.

PubMed

Wielkopolan, Beata; Obrępalska-Stęplowska, Aleksandra

2016-08-01

Coleoptera, the largest and the most diverse Insecta order, is characterized by multiple adaptations to plant feeding. Insect-associated microorganisms can be important mediators and modulators of interactions between insects and plants. Interactions between plants and insects are highly complex and involve multiple factors. There are various defense mechanisms initiated by plants upon attack by herbivorous insects, including the development of morphological structures and the synthesis of toxic secondary metabolites and volatiles. In turn, herbivores have adapted to feeding on plants and further sophisticated adaptations to overcome plant responses may continue to evolve. Herbivorous insects may detoxify toxic phytocompounds, sequester poisonous plant factors, and alter their own overall gene expression pattern. Moreover, insects are associated with microbes, which not only considerably affect insects, but can also modify plant defense responses to the benefit of their host. Plants are also frequently associated with endophytes, which may act as bioinsecticides. Therefore, it is very important to consider the factors influencing the interaction between plants and insects. Herbivorous insects cause considerable damage to global crop production. Coleoptera is the largest and the most diverse order in the class Insecta. In this review, various aspects of the interactions among insects, microbes, and plants are described with a focus on coleopteran species, their bacterial symbionts, and their plant hosts to demonstrate that many factors contribute to the success of coleopteran herbivory.

Agricultural waste material as potential adsorbent for sequestering heavy metal ions from aqueous solutions - a review.

PubMed

Sud, Dhiraj; Mahajan, Garima; Kaur, M P

2008-09-01

Heavy metal remediation of aqueous streams is of special concern due to recalcitrant and persistency of heavy metals in environment. Conventional treatment technologies for the removal of these toxic heavy metals are not economical and further generate huge quantity of toxic chemical sludge. Biosorption is emerging as a potential alternative to the existing conventional technologies for the removal and/or recovery of metal ions from aqueous solutions. The major advantages of biosorption over conventional treatment methods include: low cost, high efficiency, minimization of chemical or biological sludge, regeneration of biosorbents and possibility of metal recovery. Cellulosic agricultural waste materials are an abundant source for significant metal biosorption. The functional groups present in agricultural waste biomass viz. acetamido, alcoholic, carbonyl, phenolic, amido, amino, sulphydryl groups etc. have affinity for heavy metal ions to form metal complexes or chelates. The mechanism of biosorption process includes chemisorption, complexation, adsorption on surface, diffusion through pores and ion exchange etc. The purpose of this review article is to provide the scattered available information on various aspects of utilization of the agricultural waste materials for heavy metal removal. Agricultural waste material being highly efficient, low cost and renewable source of biomass can be exploited for heavy metal remediation. Further these biosorbents can be modified for better efficiency and multiple reuses to enhance their applicability at industrial scale.

Supercritical water oxidation for the destruction of toxic organic wastewaters: a review.

PubMed

Veriansyah, Bambang; Kim, Jae-Duck

2007-01-01

The destruction of toxic organic wastewaters from munitions demilitarization and complex industrial chemical clearly becomes an overwhelming problem if left to conventional treatment processes. Two options, incineration and supercritical water oxidation (SCWO), exist for the complete destruction of toxic organic wastewaters. Incinerator has associated problems such as very high cost and public resentment; on the other hand, SCWO has proved to be a very promising method for the treatment of many different wastewaters with extremely efficient organic waste destruction 99.99% with none of the emissions associated with incineration. In this review, the concepts of SCWO, result and present perspectives of application, and industrial status of SCWO are critically examined and discussed.

The acute toxic effects of 1-alkyl-3-methylimidazolium nitrate ionic liquids on Chlorella vulgaris and Daphnia magna.

PubMed

Zhang, Cheng; Zhang, Shuai; Zhu, Lusheng; Wang, Jinhua; Wang, Jun; Zhou, Tongtong

2017-10-01

Given their increasingly widespread application, the toxic effects of ionic liquids (ILs) have become the subject of significant attention in recent years. Therefore, the present study assessed the acute toxic effects of 1-alkyl-3-methylimidazolium nitrate ([C n mim]NO 3 (n = 2, 4, 6, 8, 10, 12)) on Chlorella vulgaris and Daphnia magna. The sensitivity of the tested organism Daphnia magna and the investigated IL concentrations in water using high-performance liquid chromatography (HPLC) were also evaluated to demonstrate the reliability of the present study. The results illustrated that Daphnia magna is indeed sensitive to the reference toxicant and the investigated ILs were stable in the aquatic environment. The 50% effect concentration (EC 50 ) was used to represent the acute toxic effects on Chlorella vulgaris and Daphnia magna. With the increasing alkyl-chain lengths, the toxicity of the investigated ILs increased in both the test organisms. Accordingly, the alkyl-chain lengths can cause significantly toxic effects on aquatic organisms, and Daphnia magna are much more sensitive than Chlorella vulgaris to the imidazolium-based ILs used in the present study. Furthermore, the present study provides more information on the acute toxic effects of 1-alkyl-3-methylimidazolium nitrate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Iron toxicity and its possible association with treatment of Cancer: lessons from hemoglobinopathies and rare, transfusion-dependent anemias.

PubMed

Puliyel, Mammen; Mainous, Arch G; Berdoukas, Vasilios; Coates, Thomas D

2015-02-01

Exposure to elevated levels of iron causes tissue damage and organ failure, and increases the risk of cancer. The toxicity of iron is mediated through generation of oxidants. There is also solid evidence indicating that oxidant stress plays a significant role in a variety of human disease states, including malignant transformation. Iron toxicity is the main focus when managing thalassemia. However, the short- and long-term toxicities of iron have not been extensively considered in children and adults treated for malignancy, and only recently have begun to draw oncologists' attention. The treatment of malignancy can markedly increase exposure of patients to elevated toxic iron species without the need for excess iron input from transfusion. This under-recognized exposure likely enhances organ toxicity and may contribute to long-term development of secondary malignancy and organ failure. This review discusses the current understanding of iron metabolism, the mechanisms of production of toxic free iron species in humans, and the relation of the clinical marker, transferrin saturation (TS), to the presence of toxic free iron. We will present epidemiological data showing that high TS is associated with poor outcomes and development of cancer, and that lowering free iron may improve outcomes. Finally, we will discuss the possible relation between some late complications seen in survivors of cancer and those due to iron toxicity. Copyright © 2014 Elsevier Inc. All rights reserved.

76 FR 11980 - Stakeholder Input: Listening Session to Provide Information and Solicit Suggestions for...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

... organisms to the surrounding water. Coatings used to deter organism growth on vessel hulls can release heavy metals and/or other biocides, which can lead to acute or chronic toxicity in non-targeted organisms. Bilgewater can contain oils, dissolved heavy metals, and other chemical constituents that can result in toxic...

Antioxidant and cytoprotective properties of D-tagatose in cultured murine hepatocytes.

PubMed

Paterna, J C; Boess, F; Stäubli, A; Boelsterli, U A

1998-01-01

D-Tagatose is a zero-energy producing ketohexose that is a powerful cytoprotective agent against chemically induced cell injury. To further explore the underlying mechanisms of cytoprotection, we investigated the effects of D-tagatose on both the generation of superoxide anion radicals and the consequences of oxidative stress driven by prooxidant compounds in intact cells. Primary cultures of hepatocytes derived from male C57BL/6 mice were exposed to the redox cycling drug nitrofurantoin (NFT). Lethal cell injury induced by 300 microM NFT was completely prevented by high concentrations (20 mM) of D-tagatose, whereas equimolar concentrations of glucose, mannitol, or xylose were ineffective. The extent of NFT-induced intracellular superoxide anion radical formation was not altered by D-tagatose, indicating that the ketohexose did not inhibit the reductive bioactivation of NFT. However, the NFT-induced decline of the intracellular GSH content was largely prevented by D-tagatose. The sugar also afforded complete protection against NFT toxicity in hepatocytes that had been chemically depleted of GSH. Furthermore, the ketohexose fully protected from increases in both membrane lipid peroxidation and protein carbonyl formation. In addition, D-tagatose completely prevented oxidative cell injury inflicted by toxic iron overload with ferric nitrilotriacetate (100 microM). In contrast, D-tagatose did not protect against lethal cell injury induced by tert-butyl hydroperoxide, a prooxidant which acts by hydroxyl radical-independent mechanisms and which is partitioned in the lipid bilayer. These results indicate that D-tagatose, which is a weak iron chelator, can antagonize the iron-dependent toxic consequences of intracellular oxidative stress in hepatocytes. The antioxidant properties of D-tagatose may result from sequestering the redox-active iron, thereby protecting more critical targets from the damaging potential of hydroxyl radical.

Glossary of Aquatic Ecological Terms,

DTIC Science & Technology

1972-02-01

changes. ACUTE TOXICITY Any toxic effect that is produced within a short period of time, usually 24-96 hours. Although the effect most frequently...considered is mortality, the end result of acute toxicity is not necessarily death. Any harmful biolopical effect may be the result. (See Chronic...manufacture of organic compounds within an organism. (See Metabolism ) 4. *1 -ib- ~:2~ ’ A- 3 I ANADROHOUS Pertaining to fishes that speid most of their

Toxicity of two imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], to standard aquatic test organisms: Role of acetone in the induced toxicity.

PubMed

Tsarpali, Vasiliki; Dailianis, Stefanos

2015-07-01

The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone. Copyright © 2015 Elsevier Inc. All rights reserved.

Toxicity of organic chemical pollution in groundwater downgradient of a landfill (Grindsted, Denmark)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baun, A.; Jensen, S.D.; Bjerg, P.L.

2000-05-01

The aim of the present study was to describe the occurrence and distribution of toxicity related to organic chemical contaminants in the leachate plume downgradient of the Grindsted Landfill (Denmark). A total of 27 groundwater samples were preconcentrated by solid-phase extraction (SPE) using XAD-2 as the resin material. This treatment effectively eliminated sample matrix toxicity caused by inorganic salts and natural organic compounds and produced an aqueous concentrate of the nonvolatile chemical contaminants. The SPE extracts were tested in a battery of standardized short-term aquatic toxicity tests with luminescent bacteria (Vibrio fischeri), algae (Selenastrum capricornutum), and crustaceans (Daphnia magna). Additionalmore » genotoxicity tests were made using the umuC test (Salmonella typhimurium). Biotests with algae and luminescent bacteria were the most sensitive tests. On the basis of results with these two bioassays, it was concluded that SPE extracts of groundwater collected close to the landfill were toxic. The toxicity decreased with the distance from the landfill. At distances greater than 80 m from the border of the landfill, the groundwater toxicity was not significantly different from the background toxicity. SPE extracts were not toxic to Daphnia, and no genotoxicity was observed in the umuC test. The overall findings indicate that a battery of biotests applied on preconcentrated groundwater samples can be a useful tool for toxicity characterization and hazard ranking of groundwater polluted with complex chemical mixtures, such as landfill leachates.« less

Computational Design of Metal Ion Sequestering Agents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, Benjamin P.; Rapko, Brian M.

Organic ligands that exhibit a high degree of metal ion recognition are essential precursors for developing separation processes and sensors for metal ions. Since the beginning of the nuclear era, much research has focused on discovering ligands that target specific radionuclides. Members of the Group 1A and 2A cations (e.g., Cs, Sr, Ra) and the f-block metals (actinides and lanthanides) are of primary concern to DOE. Although there has been some success in identifying ligand architectures that exhibit a degree of metal ion recognition, the ability to control binding affinity and selectivity remains a significant challenge. The traditional approach formore » discovering such ligands has involved lengthy programs of organic synthesis and testing that, in the absence of reliable methods for screening compounds before synthesis, have resulted in much wasted research effort.« less

Potential toxicity of pesticides measured in midwestern streams to aquatic organisms

USGS Publications Warehouse

Battaglin, W.; Fairchild, J.

2002-01-01

Society is becoming increasingly aware of the value of healthy aquatic ecosystems as well as the effects that man’s activities have on those ecosystems. In recent years, many urban and industrial sources of contamination have been reduced or eliminated. The agricultural community also has worked towards reducing off-site movement of agricultural chemicals, but their use in farming is still growing. A small fraction, estimated at <1 to 2% of the pesticides applied to crops are lost from fields and enter nearby streams during rainfall events. In many cases aquatic organisms are exposed to mixtures of chemicals, which may lead to greater non-target risk than that predicted based on traditional risk assessments for single chemicals. We evaluated the potential toxicity of environmental mixtures of 5 classes of pesticides using concentrations from water samples collected from ∼50 sites on midwestern streams during late spring or early summer runoff events in 1989 and 1998. Toxicity index values are calculated as the concentration of the compound in the sample divided by the EC50 or LC50 of an aquatic organism. These index values are summed within a pesticide class and for all classes to determine additive pesticide class and total pesticide toxicity indices. Toxicity index values greater than 1.0 indicate probable toxicity of a class of pesticides measured in a water sample to aquatic organisms. Results indicate that some samples had probable toxicity to duckweed and green algae, but few are suspected of having significant toxicity to bluegill sunfish or chorus frogs.

An evaluation of the residual toxicity and chemistry of a sodium hydroxide-based ballast water treatment system for freshwater ships.

PubMed

Elskus, Adria A; Ingersoll, Christopher G; Kemble, Nile E; Echols, Kathy R; Brumbaugh, William G; Henquinet, Jeffrey W; Watten, Barnaby J

2015-06-01

Nonnative organisms in the ballast water of freshwater ships must be killed to prevent the spread of invasive species. The ideal ballast water treatment system (BWTS) would kill 100% of ballast water organisms with minimal residual toxicity to organisms in receiving waters. In the present study, the residual toxicity and chemistry of a BWTS was evaluated. Sodium hydroxide was added to elevate pH to >11.5 to kill ballast water organisms, then reduced to pH <9 by sparging with wet-scrubbed diesel exhaust (the source of CO2 ). Cladocerans (Ceriodaphnia dubia), amphipods (Hyalella azteca), and fathead minnows (Pimephales promelas) were exposed for 2 d to BWTS water under an air atmosphere (pH drifted to ≥9) or a 2.5% CO2 atmosphere (pH 7.5-8.2), then transferred to control water for 5 d to assess potential delayed toxicity. Chemical concentrations in the BWTS water met vessel discharge guidelines with the exception of concentrations of copper. There was little to no residual toxicity to cladocerans or fish, but the BWTS water was toxic to amphipods. Maintaining a neutral pH and diluting BWTS water by 50% eliminated toxicity to the amphipods. The toxicity of BWTS water would likely be minimal because of rapid dilution in the receiving water, with subsurface release likely preventing pH rise. This BWTS has the potential to become a viable method for treating ballast water released into freshwater systems. © 2015 SETAC.

Mountain respiration: Rates and patterns of fossil organic carbon oxidation revealed using the trace element rhenium

NASA Astrophysics Data System (ADS)

Hilton, R. G.; Gaillardet, J.; Calmels, D.; Birck, J.

2013-12-01

Fossil organic carbon (OCfossil) from sedimentary rocks can contribute to the carbon stock within the deepest part of soil. OCfossil constitutes a vast stock of carbon that was sequestered from the atmosphere in the geological past, containing ~15x106 PgC, which is approximately 25,000 times the carbon content of the pre-industrial atmosphere. Oxidation of OCfossil during chemical weathering at Earth's surface is thought to be a major source of carbon dioxide (CO2) to the atmosphere. It has been proposed that OCfossil oxidation occurs when fresh sedimentary rocks are exposed to oxygenated water, with the rate of CO2 release controlled by the supply of OCfossil to react. As such, mountain belts where high rates of physical erosion provide an abundant supply of OCfossil to the soil critical zone should be locations where this CO2 source is most potent. However, the rates of OCfossil oxidation during weathering remain poorly constrained. Here we use the trace element rhenium (Re) to shed new light on the rates and patterns of OCfossil oxidation across the landscape. Re is known to be associated with organic matter in rocks and following oxidation forms a soluble anion which contributes to the dissolved load of rivers. Rivers can offer an integrated signal of chemical reactions occurring across the landscape, and so by quantifying the dissolved Re flux we are able to estimate the corresponding release of CO2 by OCfossil weathering. Using a set of mountain river catchments in Taiwan, where water and sediment fluxes are well quantified, we estimate that the rates of CO2 output by this process are significant, and encroach on values expected for net biome productivity. We find that OCfossil oxidation rates are strongly linked to physical erosion rate at the catchment-scale. This suggests that changes in the rates of surface processes may alter this CO2 output from deep soils. On longer timescales, our findings suggest that the total CO2 output by OCfossil weathering in Taiwan does not negate estimates of CO2 sequestration by erosion and sedimentary burial of recent organic matter. Our findings suggest that mountain building in the tropic can result in a net sink of organic carbon during erosion and weathering which acts to sequester atmospheric CO2.

PH DEPENDENT TOXICITY OF FIVE METALS TO THREE MARINE ORGANISMS

EPA Science Inventory

The pH of natural marine systems is relatively stable; this may explain why metal toxicity changes with pH have not been well documented. However, changes in metal toxicity with pH in marine waters are of concern in toxicity testing. During porewater toxicity testing pH can chang...

Naive CD8 T-Cells Initiate Spontaneous Autoimmunity to a Sequestered Model Antigen of the Central Nervous System

ERIC Educational Resources Information Center

Na, Shin-Young; Cao, Yi; Toben, Catherine; Nitschke, Lars; Stadelmann, Christine; Gold, Ralf; Schimpl, Anneliese; Hunig, Thomas

2008-01-01

In multiple sclerosis, CD8 T-cells are thought play a key pathogenetic role, but mechanistic evidence from rodent models is limited. Here, we have tested the encephalitogenic potential of CD8 T-cells specific for the model antigen ovalbumin (OVA) sequestered in oligodendrocytes as a cytosolic molecule. We show that in these "ODC-OVA" mice, the…

IMPROVEMENT IN AIR TOXICS METHODS FOR VOLATILE ORGANIC COMPOUNDS

EPA Science Inventory

Innovative and customized monitoring methods for air toxic volatile organic compounds (VOCs) are being developed for applications in exposure and trends monitoring. This task addresses the following applications of specific interest:

o Contributions to EPA Regional Monit...

Economic Analysis of Planting Forests on Rice Lands in Texas: Sequestering Carbon and Avoiding Methane Production

NASA Astrophysics Data System (ADS)

Kronrad, G. D.; Huang, C.

2005-12-01

Global climate change is predicted due to increases in greenhouse gasses (i.e. CO2, CH4, CFCs, N2O, O3) in the atmosphere caused by human activities. The atmospheric concentration of methane (CH4), which absorbs and retains heat 21 times more effectively than CO2, has increased. Anaerobic bacterial activity in rice paddies constitutes one of major emission sources of CH4. The rice fields of Texas, for example, accounted for an annual CH4 emission of between 1.1 and 1.6 million tons of CO2 equivalent between 1990 and 2000. Converting marginal rice fields to forests plantations will remove CO2 from the atmosphere, sequester carbon in the forests and prevent the production of CH4. Therefore, carbon credits can be claimed for the carbon sequestered and the avoidance of CH4 production. Analyses were conducted to calculate the amount of carbon sequestered and methane avoided, and the profitability, measured in net present worth (NPW), of managing loblolly pine plantation for 1) timber production only, 2) the dual products of timber products and carbon credits in forests planted on marginal agricultural and unused pastureland and 3) the dual products of timber and carbon storage in forests planted on marginal rice lands. Calculations were performed using three discount rates, three site qualities and five prices for carbon credits. The results indicate that on average quality land, using a discount rate of 8 percent, forests planted on marginal agricultural and unused pastureland earn a NPW of 346 per acre from timber production only; a NPW of 438 per acre from timber and carbon credits (54.4 tons of carbon sequestered), assuming carbon is worth 10 per ton, during one rotation (32 years). The profitability of forest management increases due to the inclusion of carbon credits. The profitability of planting forests on marginal rice fields is even higher, earning a NPW of 566 per acre from timber and carbon credits (54.4 tons of C sequestered and 33.3 tons of C emission avoided).

Editor's Highlight: Transgenic Zebrafish Reporter Lines as Alternative In Vivo Organ Toxicity Models.

PubMed

Poon, Kar Lai; Wang, Xingang; Lee, Serene G P; Ng, Ashley S; Goh, Wei Huang; Zhao, Zhonghua; Al-Haddawi, Muthafar; Wang, Haishan; Mathavan, Sinnakaruppan; Ingham, Philip W; McGinnis, Claudia; Carney, Tom J

2017-03-01

Organ toxicity, particularly liver toxicity, remains one of the major reasons for the termination of drug candidates in the development pipeline as well as withdrawal or restrictions of marketed drugs. A screening-amenable alternative in vivo model such as zebrafish would, therefore, find immediate application in the early prediction of unacceptable organ toxicity. To identify highly upregulated genes as biomarkers of toxic responses in the zebrafish model, a set of well-characterized reference drugs that cause drug-induced liver injury (DILI) in the clinic were applied to zebrafish larvae and adults. Transcriptome microarray analysis was performed on whole larvae or dissected adult livers. Integration of data sets from different drug treatments at different stages identified common upregulated detoxification pathways. Within these were candidate biomarkers which recurred in multiple treatments. We prioritized 4 highly upregulated genes encoding enzymes acting in distinct phases of the drug metabolism pathway. Through promoter isolation and fosmid recombineering, eGFP reporter transgenic zebrafish lines were generated and evaluated for their response to DILI drugs. Three of the 4 generated reporter lines showed a dose and time-dependent induction in endodermal organs to reference drugs and an expanded drug set. In conclusion, through integrated transcriptomics and transgenic approaches, we have developed parallel independent zebrafish in vivo screening platforms able to predict organ toxicities of preclinical drugs. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Overview of data and conceptual approaches for derivation of quantitative structure-activity relationships for ecotoxicological effects of organic chemicals.

PubMed

Bradbury, Steven P; Russom, Christine L; Ankley, Gerald T; Schultz, T Wayne; Walker, John D

2003-08-01

The use of quantitative structure-activity relationships (QSARs) in assessing potential toxic effects of organic chemicals on aquatic organisms continues to evolve as computational efficiency and toxicological understanding advance. With the ever-increasing production of new chemicals, and the need to optimize resources to assess thousands of existing chemicals in commerce, regulatory agencies have turned to QSARs as essential tools to help prioritize tiered risk assessments when empirical data are not available to evaluate toxicological effects. Progress in designing scientifically credible QSARs is intimately associated with the development of empirically derived databases of well-defined and quantified toxicity endpoints, which are based on a strategic evaluation of diverse sets of chemical structures, modes of toxic action, and species. This review provides a brief overview of four databases created for the purpose of developing QSARs for estimating toxicity of chemicals to aquatic organisms. The evolution of QSARs based initially on general chemical classification schemes, to models founded on modes of toxic action that range from nonspecific partitioning into hydrophobic cellular membranes to receptor-mediated mechanisms is summarized. Finally, an overview of expert systems that integrate chemical-specific mode of action classification and associated QSAR selection for estimating potential toxicological effects of organic chemicals is presented.

Removal of organic contaminant toxicity from sediments - Early work toward development of a toxicity identification evaluation (TIE) method

USGS Publications Warehouse

Lebo, J.A.; Huckins, J.N.; Petty, J.D.; Ho, K.T.

1999-01-01

Work was performed to determine the feasibility of selectively detoxifying organic contaminants in sediments. The results of this research will be used to aid in the development of a scheme for whole-sediment toxicity identification evaluations (TIEs). The context in which the method will be used inherently restricts the treatments to which the sediments can be subjected: Sediments cannot be significantly altered physically or chemically and the presence and bioavailabilities of other toxicants must not be changed. The methodological problem is daunting because of the requirement that the detoxification method be relatively fast and convenient together with the stipulation that only innocuous and minimally invasive treatments be used. Some of the experiments described here dealt with degrees of decontamination (i.e., detoxification as predicted from instrumental measurements) of spiked sediments rather than with degrees of detoxification as gauged by toxicity tests (e.g., 48-h toxicity tests with amphipods). Although the larger TIE scheme itself is mostly outside the scope of this paper, theoretical aspects of bioavailability and of the desorption of organic contaminants from sediments are discussed.

CHARACTERIZATION AND ISOLATION OF ORGANIC TOXICANTS IN WHOLE SEDIMENT TOXICITY INDENTIFICATION EVALUATIONS (TIES)

EPA Science Inventory

Development of whole sediment toxicity identification and evaluation (TIEs) methods has been under way for approximately four years. These methods are necessary to define cause and effect relationships in toxic sediments during ecological risk assessments, remediation and disposa...

Integration of genomic endpoints into toxicity identification evaluations

EPA Science Inventory

Toxicity identification and evaluations (TIEs) use physical/chemical manipulation of a sample to isolate or change the potency of different groups of toxicants potentially present in a sample. Organisms are then exposed to these fractions to determine if their toxicity has change...

The discovery and development of proteomic safety biomarkers for the detection of drug-induced liver toxicity.

PubMed

Amacher, David E

2010-05-15

Biomarkers are biometric measurements that provide critical quantitative information about the biological condition of the animal or individual being tested. In drug safety studies, established toxicity biomarkers are used along with other conventional study data to determine dose-limiting organ toxicity, and to define species sensitivity for new chemical entities intended for possible use as human medicines. A continuing goal of drug safety scientists in the pharmaceutical industry is to discover and develop better trans-species biomarkers that can be used to determine target organ toxicities for preclinical species in short-term studies at dose levels that are some multiple of the intended human dose and again later in full development for monitoring clinical trials at lower therapeutic doses. Of particular value are early, predictive, noninvasive biomarkers that have in vitro, in vivo, and clinical transferability. Such translational biomarkers bridge animal testing used in preclinical science and human studies that are part of subsequent clinical testing. Although suitable for in vivo preclinical regulatory studies, conventional hepatic safety biomarkers are basically confirmatory markers because they signal organ toxicity after some pathological damage has occurred, and are therefore not well-suited for short-term, predictive screening assays early in the discovery-to-development progression of new chemical entities (NCEs) available in limited quantities. Efforts between regulatory agencies and the pharmaceutical industry are underway for the coordinated discovery, qualification, verification and validation of early predictive toxicity biomarkers. Early predictive safety biomarkers are those that are detectable and quantifiable prior to the onset of irreversible tissue injury and which are associated with a mechanism of action relevant to a specific type of potential hepatic injury. Potential drug toxicity biomarkers are typically endogenous macromolecules in biological fluids with varying immunoreactivity which can present bioanalytical challenges when first discovered. The potential success of these efforts is greatly enhanced by recent advances in two closely linked technologies, toxicoproteomics and targeted, quantitative mass spectrometry. This review focuses on the examination of the current status of these technologies as they relate to the discovery and development of novel preclinical biomarkers of hepatotoxicity. A critical assessment of the current literature reveals two distinct lines of safety biomarker investigation, (1) peripheral fluid biomarkers of organ toxicity and (2) tissue or cell-based toxicity signatures. Improved peripheral fluid biomarkers should allow the sensitive detection of potential organ toxicity prior to the onset of overt organ pathology. Advancements in tissue or cell-based toxicity biomarkers will provide sensitive in vitro or ex vivo screening systems based on toxicity pathway markers. An examination of the current practices in clinical pathology and the critical evaluation of some recently proposed biomarker candidates in comparison to the desired characteristics of an ideal toxicity biomarker lead this author to conclude that a combination of selected biomarkers will be more informative if not predictive of potential animal organ toxicity than any single biomarker, new or old. For the practical assessment of combinations of conventional and/or novel toxicity biomarkers in rodent and large animal preclinical species, mass spectrometry has emerged as the premier analytical tool compared to specific immunoassays or functional assays. Selected and multiple reaction monitoring mass spectrometry applications make it possible for this same basic technology to be used in the progressive stages of biomarker discovery, development, and more importantly, routine study applications without the use of specific antibody reagents. This technology combined with other "omics" technologies can provide added selectivity and sensitivity in preclinical drug safety testing.

Acute toxicity, twenty-eight days repeated dose toxicity and genotoxicity of vanadyl trehalose in kunming mice.

PubMed

Jiang, Pingzhe; Ni, Zaizhong; Wang, Bin; Ma, Baicheng; Duan, Huikun; Li, Xiaodan; Ma, Xiaofeng; Wei, Qian; Ji, Xiangzhen; Liu, Qiqi; Xing, Shuguang; Li, Minggang

2017-04-01

A new trend has been developed using vanadium and organic ligands to form novel compounds in order to improve the beneficial actions and reduce the toxicity of vanadium compounds. In present study, vanadyl trehalose was explored the oral acute toxicity, 28 days repeated dose toxicity and genotoxicity in Kunming mice. The Median Lethal Dose (LD 50 ) of vanadyl trehalose was revealed to be 1000 mg/kg body weight in fasted Kunming mice. Stomach and intestine were demonstrated to be the main target organs of vanadyl trehalose through 28 days repeated dose toxicity study. And vanadyl trehalose also showed particular genotoxicity through mouse bone marrow micronucleus and mouse sperm malformation assay. In brief, vanadyl trehalose presented certain, but finite toxicity, which may provide experimental basis for the clinical application. Copyright © 2017 Elsevier Inc. All rights reserved.

Cellular Inclusion Bodies of Mutant Huntingtin Exon 1 Obscure Small Fibrillar Aggregate Species

PubMed Central

Sahl, Steffen J.; Weiss, Lucien E.; Duim, Whitney C.; Frydman, Judith; Moerner, W. E.

2012-01-01

The identities of toxic aggregate species in Huntington's disease pathogenesis remain ambiguous. While polyQ-expanded huntingtin (Htt) is known to accumulate in compact inclusion bodies inside neurons, this is widely thought to be a protective coping response that sequesters misfolded conformations or aggregated states of the mutated protein. To define the spatial distributions of fluorescently-labeled Htt-exon1 species in the cell model PC12m, we employed highly sensitive single-molecule super-resolution fluorescence imaging. In addition to inclusion bodies and the diffuse pool of monomers and oligomers, fibrillar aggregates ~100 nm in diameter and up to ~1–2 µm in length were observed for pathogenic polyQ tracts (46 and 97 repeats) after targeted photo-bleaching of the inclusion bodies. These short structures bear a striking resemblance to fibers described in vitro. Definition of the diverse Htt structures in cells will provide an avenue to link the impact of therapeutic agents to aggregate populations and morphologies. PMID:23193437

The emerging role of lysosomes in copper homeostasis.

PubMed

Polishchuk, Elena V; Polishchuk, Roman S

2016-09-01

The lysosomal system operates as a focal point where a number of important physiological processes such as endocytosis, autophagy and nutrient sensing converge. One of the key functions of lysosomes consists of regulating the metabolism/homeostasis of metals. Metal-containing components are carried to the lysosome through incoming membrane flows, while numerous transporters allow metal ions to move across the lysosome membrane. These properties enable lysosomes to direct metal fluxes to the sites where metal ions are either used by cellular components or sequestered. Copper belongs to a group of metals that are essential for the activity of vitally important enzymes, although it is toxic when in excess. Thus, copper uptake, supply and intracellular compartmentalization have to be tightly regulated. An increasing number of publications have indicated that these processes involve lysosomes. Here we review studies that reveal the expanding role of the lysosomal system as a hub for the control of Cu homeostasis and for the regulation of key Cu-dependent processes in health and disease.

Cadmium localization and quantification in the plant Arabidopsis thaliana using micro-PIXE

NASA Astrophysics Data System (ADS)

Ager, F. J.; Ynsa, M. D.; Domínguez-Solís, J. R.; Gotor, C.; Respaldiza, M. A.; Romero, L. C.

2002-04-01

Remediation of metal-contaminated soils and waters poses a challenging problem due to its implications in the environment and the human health. The use of metal-accumulating plants to remove toxic metals, including Cd, from soil and aqueous streams has been proposed as a possible solution to this problem. The process of using plants for environmental restoration is termed phytoremediation. Cd is a particularly favourable target metal for this technology because it is readily transported and accumulated in the shoots of several plant species. This paper investigates the sites of metal localization within Arabidopsis thaliana leaves, when plants are grown in a cadmium-rich environment, by making use of nuclear microscopy techniques. Micro-PIXE, RBS and SEM analyses were performed on the scanning proton microprobe at the CNA in Seville (Spain), showing that cadmium is sequestered within the trichomes on the leaf surface. Additionally, regular PIXE analyses were performed on samples prepared by an acid digestion method in order to assess the metal accumulation of such plants.

Vaults Engineered for Hydrophobic Drug Delivery

PubMed Central

Buehler, Daniel C.; Toso, Daniel B.; Kickhoefer, Valerie A.; Zhou, Z. Hong

2013-01-01

The vault nanoparticle is one of the largest known ribonucleoprotein complexes in the sub-100 nm range. Highly conserved and almost ubiquitously expressed in eukaryotes, vaults form a large nanocapsule with a barrel-shaped morphology surrounding a large hollow interior. These properties make vaults an ideal candidate for development into a drug delivery vehicle. In this study, we report the first example of using vaults towards this goal. We engineered recombinant vaults to encapsulate the highly insoluble and toxic hydrophobic compound All-trans Retinoic Acid (ATRA) using a vault binding lipoprotein complex that forms a lipid bilayer nanodisk. These recombinant vaults offer protection to the encapsulated ATRA from external elements. Furthermore, a cryo-electron tomography (cryo-ET) reconstruction shows the vault binding lipoprotein complex sequestered within the vault lumen. Finally, these ATRA loaded vaults have enhanced cytotoxicity against the hepatocellular carcinoma cell line HepG2. The ability to package therapeutic compounds into the vault is an important achievement toward their development into a viable and versatile platform for drug delivery. PMID:21506266

Proteomic Analysis of Acetaminophen-Induced Changes in Mitochondrial Protein Expression Using Spectral Counting

PubMed Central

Stamper, Brendan D.; Mohar, Isaac; Kavanagh, Terrance J.; Nelson, Sidney D.

2011-01-01

Comparative proteomic analysis following treatment with acetaminophen (APAP) was performed on two different models of APAP-mediated hepatocellular injury in order to both identify common targets for adduct formation and track drug-induced changes in protein expression. Male C57BL/6 mice were used as a model for APAP-mediated liver injury in vivo and TAMH cells were used as a model for APAP-mediated cytotoxicity in vitro. SEQUEST was unable to identify the precise location of sites of adduction following treatment with APAP in either system. However, semiquantitative analysis of the proteomic datasets using spectral counting revealed a downregulation of P450 isoforms associated with APAP bioactivation, and an upregulation of proteins related to the electron transport chain by APAP compared to control. Both mechanisms are likely compensatory in nature as decreased P450 expression is likely to attenuate toxicity associated with N-acetyl-p-quinoneimine (NAPQI) formation, whereas APAP-induced electron transport chain component upregulation may be an attempt to promote cellular bioenergetics. PMID:21329376

Probing active cocaine vaccination performance through catalytic and noncatalytic hapten design.

PubMed

Cai, Xiaoqing; Whitfield, Timothy; Hixon, Mark S; Grant, Yanabel; Koob, George F; Janda, Kim D

2013-05-09

Presently, there are no FDA-approved medications to treat cocaine addiction. Active vaccination has emerged as one approach to intervene through the rapid sequestering of the circulating drug, thus terminating both psychoactive effects and drug toxicity. Herein, we report our efforts examining two complementary, but mechanistically distinct active vaccines, i.e., noncatalytic and catalytic, for cocaine treatment. A cocaine-like hapten GNE and a cocaine transition-state analogue GNT were used to generate the active vaccines, respectively. GNE-KLH (keyhole limpet hemocyannin) was found to elicit persistent high-titer, cocaine-specific antibodies and blunt cocaine-induced locomotor behaviors. Catalytic antibodies induced by GNT-KLH were also shown to produce potent titers and suppress locomotor response in mice; however, upon repeated cocaine challenges, the vaccine's protecting effects waned. In depth kinetic analysis suggested that loss of catalytic activity was due to antibody modification by cocaine. The work provides new insights for the development of active vaccines for the treatment of cocaine abuse.

Bacterial cocaine esterase: a protein-based therapy for cocaine overdose and addiction

PubMed Central

Narasimhan, Diwahar; Woods, James H; Sunahara, Roger K

2012-01-01

Cocaine is highly addictive and there are no pharmacotherapeutic drugs available to treat acute cocaine toxicity or chronic abuse. Antagonizing an inhibitor such as cocaine using a small molecule has proven difficult. The alternative approach is to modify cocaine’s pharmacokinetic properties by sequestering or hydrolyzing it in serum and limiting access to its sites of action. We took advantage of a bacterial esterase (CocE) that has evolved to hydrolyze cocaine and have developed it as a therapeutic that rapidly and specifically clears cocaine from the subject. Native enzyme was unstable at 37°C, thus limiting CocE’s potential. Innovative computational methods based on the protein’s structure helped elucidate its mechanism of destabilization. Novel protein engineering methodologies were applied to substantially improve its stability in vitro and in vivo. These improvements rendered CocE as a powerful and efficacious therapeutic to treat cocaine intoxication and lead the way towards developing a therapy for addiction. PMID:22300094

Probing Active Cocaine Vaccination Performance through Catalytic and Noncatalytic Hapten Design

PubMed Central

Cai, Xiaoqing; Whitfield, Timothy; Hixon, Mark S.; Grant, Yanabel; Koob, George F.; Janda, Kim D.

2013-01-01

Presently, there are no FDA-approved medications to treat cocaine addiction. Active vaccination has emerged as one approach to intervene through the rapid sequestering of the circulating drug, thus terminating both psychoactive effects and drug toxicity. Herein, we report our efforts examining two complimentary, but mechanistically distinct active vaccines, i.e., noncatalytic and catalytic, for cocaine treatment. A cocaine-like hapten GNE and a cocaine transition-state analogue GNT were used to generate the active vaccines, respectively. GNE-KLH was found to elicit persistent high-titer, cocaine-specific antibodies, and blunt cocaine induced locomotor behaviors. Catalytic antibodies induced by GNT-KLH were also shown to produce potent titers and suppress locomotor response in mice; however, upon repeated cocaine challenges the vaccine’s protecting effects waned. In depth kinetic analysis suggested that loss of catalytic activity was due to antibody modification by cocaine. The work provides new insights for the development of active vaccines for the treatment of cocaine abuse. PMID:23627877

Evolutionary assembly of the milkweed fauna: cytochrome oxidase I and the age of Tetraopes beetles.

PubMed

Farrell, B D

2001-03-01

The insects that feed on the related plant families Apocynaceae and Asclepiadaceae (here collectively termed "milkweeds") comprise a "component community" of highly specialized, distinctive lineages of species that frequently sequester toxic cardiac glycosides from their host plants for defense against predators and are thus often aposematic, advertising their consequent unpalatability. Such sets of specialized lineages provide opportunities for comparative studies of the rate of adaptation, diversification, and habitat-related effects on molecular evolution. The cerambycid genus Tetraopes is the most diverse of the new world milkweed herbivores and the species are generally host specific, being restricted to single, different species of Asclepias, more often so than most other milkweed insects. Previous work revealed correspondence between the phylogeny of these beetles and that of their hosts. The present study provides analyses of near-complete DNA sequences for Tetraopes and relatives that are used to establish a molecular clock and temporal framework for Tetraopes evolution with their milkweed hosts. Copyright 2001 Academic Press.

Non-Covalent Functionalization of Carbon Nanovectors with an Antibody Enables Targeted Drug Delivery

PubMed Central

Berlin, Jacob M.; Pham, Tam T.; Sano, Daisuke; Mohamedali, Khalid A.; Marcano, Daniela C.; Myers, Jeffrey N.; Tour, James M.

2011-01-01

Current chemotherapeutics are characterized by efficient tumor cell-killing and severe side effects mostly derived from off target toxicity. Hence targeted delivery of these drugs to tumor cells is actively sought. We previously demonstrated that poly(ethylene glycol)-functionalized carbon nanovectors are able to sequester paclitaxel, a widely used hydrophobic cancer drug, by simple physisorption and deliver the drug for killing of cancer cells. The cell-killing when these drug-loaded carbon nanoparticles were used was equivalent to when a commercial formulation of paclitaxel was used. Here we show that by further mixing the drug-loaded nanoparticles with Cetuximab, a monoclonal antibody that recognizes the epidermal growth factor receptor (EGFR), paclitaxel is preferentially targeted to EGFR+ tumor cells in vitro. This supports progressing to in vivo studies. Moreover, the construct is unusual in that all three components are assembled through non-covalent interactions. Such non-covalent assembly could enable high-throughput screening of drug/antibody combinations. PMID:21736358

Gold coated lanthanide phosphate nanoparticles for targeted alpha generator radiotherapy.

PubMed

McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose A; Wall, Jonathan S; Rondinone, Adam J; Kennel, Stephen J; Mirzadeh, Saed; Robertson, J David

2013-01-01

Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo α-generator targeted radiotherapies can deliver multiple α particles to a receptor site dramatically amplifying the radiation dose delivered to the target. The major challenge with α-generator radiotherapies is that traditional chelating moieties are unable to sequester the radioactive daughters in the bioconjugate which is critical to minimize toxicity to healthy, non-target tissue. The recoil energy of the (225)Ac daughters following α decay will sever any metal-ligand bond used to form the bioconjugate. This work demonstrates that an engineered multilayered nanoparticle-antibody conjugate can deliver multiple α radiations and contain the decay daughters of (225)Ac while targeting biologically relevant receptors in a female BALB/c mouse model. These multi-shell nanoparticles combine the radiation resistance of lanthanide phosphate to contain (225)Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established gold chemistry for attachment of targeting moieties.

Preliminary study of injury from heating systemically delivered, nontargeted dextran–superparamagnetic iron oxide nanoparticles in mice

PubMed Central

Kut, Carmen; Zhang, Yonggang; Hedayati, Mohammad; Zhou, Haoming; Cornejo, Christine; Bordelon, David; Mihalic, Jana; Wabler, Michele; Burghardt, Elizabeth; Gruettner, Cordula; Geyh, Alison; Brayton, Cory; Deweese, Theodore L; Ivkov, Robert

2013-01-01

Aim To assess the potential for injury to normal tissues in mice due to heating systemically delivered magnetic nanoparticles in an alternating magnetic field (AMF). Materials & methods Twenty three male nude mice received intravenous injections of dextran–superparamagnetic iron oxide nanoparticles on days 1–3. On day 6, they were exposed to AMF. On day 7, blood, liver and spleen were harvested and analyzed. Results Iron deposits were detected in the liver and spleen. Mice that had received a high-particle dose and a high AMF experienced increased mortality, elevated liver enzymes and significant liver and spleen necrosis. Mice treated with low-dose superparamagnetic iron oxide nanoparticles and a low AMF survived, but had elevated enzyme levels and local necrosis in the spleen. Conclusion Magnetic nanoparticles producing only modest heat output can cause damage, and even death, when sequestered in sufficient concentrations. Dextran–superparamagnetic iron oxide nanoparticles are deposited in the liver and spleen, making these the sites of potential toxicity. PMID:22830502

sRNA antitoxins: more than one way to repress a toxin.

PubMed

Wen, Jia; Fozo, Elizabeth M

2014-08-04

Bacterial toxin-antitoxin loci consist of two genes: one encodes a potentially toxic protein, and the second, an antitoxin to repress its function or expression. The antitoxin can either be an RNA or a protein. For type I and type III loci, the antitoxins are RNAs; however, they have very different modes of action. Type I antitoxins repress toxin protein expression through interacting with the toxin mRNA, thereby targeting the mRNA for degradation or preventing its translation or both; type III antitoxins directly bind to the toxin protein, sequestering it. Along with these two very different modes of action for the antitoxin, there are differences in the functions of the toxin proteins and the mobility of these loci between species. Within this review, we discuss the major differences as to how the RNAs repress toxin activity, the potential consequences for utilizing different regulatory strategies, as well as the confirmed and potential biological roles for these loci across bacterial species.

Distinct loops in arrestin differentially regulate ligand binding within the GPCR opsin

PubMed Central

Sommer, Martha E.; Hofmann, Klaus Peter; Heck, Martin

2012-01-01

G-protein-coupled receptors are universally regulated by arrestin binding. Here we show that rod arrestin induces uptake of the agonist all-trans-retinol in only half the population of phosphorylated opsin in the native membrane. Agonist uptake blocks subsequent entry of the inverse agonist 11-cis-retinal (that is, regeneration of rhodopsin), but regeneration is not blocked in the other half of aporeceptors. Environmentally sensitive fluorophores attached to arrestin reported that conformational changes in loopV−VI (N-domain) are coupled to the entry of agonist, while loopXVIII−XIX (C-domain) engages the aporeceptor even before agonist is added. The data are most consistent with a model in which each domain of arrestin engages its own aporeceptor, and the different binding preferences of the domains lead to asymmetric ligand binding by the aporeceptors. Such a mechanism would protect the rod cell in bright light by concurrently sequestering toxic all-trans-retinol and allowing regeneration with 11-cis-retinal. PMID:22871814

Distinct loops in arrestin differentially regulate ligand binding within the GPCR opsin.

PubMed

Sommer, Martha E; Hofmann, Klaus Peter; Heck, Martin

2012-01-01

G-protein-coupled receptors are universally regulated by arrestin binding. Here we show that rod arrestin induces uptake of the agonist all-trans-retinal [corrected] in only half the population of phosphorylated opsin in the native membrane. Agonist uptake blocks subsequent entry of the inverse agonist 11-cis-retinal (that is, regeneration of rhodopsin), but regeneration is not blocked in the other half of aporeceptors. Environmentally sensitive fluorophores attached to arrestin reported that conformational changes in loop(V-VI) (N-domain) are coupled to the entry of agonist, while loop(XVIII-XIX) (C-domain) engages the aporeceptor even before agonist is added. The data are most consistent with a model in which each domain of arrestin engages its own aporeceptor, and the different binding preferences of the domains lead to asymmetric ligand binding by the aporeceptors. Such a mechanism would protect the rod cell in bright light by concurrently sequestering toxic all-trans-retinal [corrected] and allowing regeneration with 11-cis-retinal.

Aflatoxin Toxicity Reduction in Feed by Enhanced Binding to Surface-Modified Clay Additives

PubMed Central

Jaynes, William F.; Zartman, Richard E.

2011-01-01

Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (Kd = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (Kd = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (Kd = 13,800) and carnitine (Kd = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (Kd = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (Kd = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (Kd = 1340) or the untreated montmorillonite (Kd = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity. PMID:22069725

Aflatoxin toxicity reduction in feed by enhanced binding to surface-modified clay additives.

PubMed

Jaynes, William F; Zartman, Richard E

2011-06-01

Animal feeding studies have demonstrated that clay additives, such as bentonites, can bind aflatoxins in ingested feed and reduce or eliminate the toxicity. Bentonite deposits are found throughout the world and mostly consist of expandable smectite minerals, such as montmorillonite. The surfaces of smectite minerals can be treated with organic compounds to create surface-modified clays that more readily bind some contaminants than the untreated clay. Montmorillonites treated with organic cations, such as hexadecyltrimethylammonium (HDTMA) and phenyltrimethylammonium (PTMA), more effectively remove organic contaminants, such as benzene and toluene, from water than untreated clay. Similarly, montmorillonite treated with PTMA (K(d) = 24,100) retained more aflatoxin B1 (AfB1) from aqueous corn flour than untreated montmorillonite (K(d) = 944). Feed additives that reduced aflatoxin toxicity in animal feeding studies adsorbed more AfB1 from aqueous corn flour than feed additives that were less effective. The organic cations HDTMA and PTMA are considered toxic and would not be suitable for clay additives used in feed or food, but other non-toxic or nutrient compounds can be used to prepare surface-modified clays. Montmorillonite (SWy) treated with choline (K(d) = 13,800) and carnitine (K(d) = 3960) adsorbed much more AfB1 from aqueous corn flour than the untreated clay (K(d) = 944). A choline-treated clay prepared from a reduced-charge, high-charge montmorillonite (K(d) = 20,100) adsorbed more AfB1 than the choline-treated high-charge montmorillonite (K(d) = 1340) or the untreated montmorillonite (K(d) = 293). Surface-modified clay additives prepared using low-charge smectites and nutrient or non-toxic organic compounds might be used to more effectively bind aflatoxins in contaminated feed or food and prevent toxicity.

Toxicity of natural mixtures of organic pollutants in temperate and polar marine phytoplankton.

PubMed

Echeveste, Pedro; Galbán-Malagón, Cristóbal; Dachs, Jordi; Berrojalbiz, Naiara; Agustí, Susana

2016-11-15

Semivolatile and persistent organic pollutants (POPs) undergo atmospheric transport before being deposited to the oceans, where they partition to phytoplankton organic matter. The goal of this study was to determine the toxicity of naturally occurring complex mixtures of organic pollutants to temperate and polar phytoplankton communities from the Mediterranean Sea, the North East (NE) Atlantic, and Southern Oceans. The cell abundance of the different phytoplankton groups, chlorophyll a concentrations, viability of the cells, and growth and decay constants were monitored in response to addition of a range of concentrations of mixtures of organic pollutants obtained from seawater extracts. Almost all of the phytoplankton groups were significantly affected by the complex mixtures of non-polar and polar organic pollutants, with toxicity being greater for these mixtures than for single POPs or simple POP mixtures. Cocktails' toxicity arose at concentrations as low as tenfold the field oceanic levels, probably due to a higher chemical activity of the mixture than of simple POPs mixtures. Overall, smaller cells were the most affected, although Mediterranean picophytoplankton was significantly more tolerant to non-polar POPs than picophytoplankton from the Atlantic Ocean or the Bellingshausen Sea microphytoplankton. Copyright © 2016 Elsevier B.V. All rights reserved.

Validation of Microtox as a first screening tool for waste classification.

PubMed

Weltens, R; Deprez, K; Michiels, L

2014-12-01

The Waste Framework Directive (WFD; 2008/98/EG) describes how waste materials are to be classified as hazardous or not. For complex waste materials chemical analyses are often not conclusive and the WFD provides the possibility to assess the hazardous properties by testing on the waste materials directly. As a methodology WFD refers to the protocols described in the CLP regulation (regulation on Classification, Labeling and Packaging of chemicals) but the toxicity tests on mammals are not acceptable for waste materials. The DISCRISET project was initiated to investigate the suitability of alternative toxicity tests that are already in use in pharmaceutical applications, for the toxicological hazard assessment of complex waste materials. Results indicated that Microtox was a good candidate as a first screening test in a tiered approached hazard assessment. This is now further validated in the present study. The toxic responses measured in Microtox were compared to biological responses in other bioassays for both organic and inorganic fractions of the wastes. Both fractions contribute to the toxic load of waste samples. Results show that the Microtox test is indeed a good and practical screening tool for the organic fraction. A screening threshold (ST) of 5 geq/l as the EC50 value in Microtox is proposed as this ST allows to recognize highly toxic samples in the screening test. The data presented here show that the Microtox toxicity response at this ST is not only predictive for acute toxicity in other organisms but also for sub lethal toxic effects of the organic fraction. This limit value has to be further validated. For the inorganic fraction no specific biotest can be recommended as a screening test, but the use of direct toxicity assessment is also preferable for this fraction as metal speciation is an important issue to define the toxic load of elutriate fractions. A battery of 3 tests (Microtox, Daphnia and Algae) for direct toxicity assessment of this fraction is recommended in literature, but including tests for mechanistic toxicity might be useful. Copyright © 2014 Elsevier Ltd. All rights reserved.

40 CFR 433.12 - Monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... indirect dischargers, the control authority) may allow dischargers to make the following certification... the permit limitation [or pretreatment standard] for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters...

ISOLATING AND EVALUATING ORGANIC TOXICANTS IN SEDIMENTS: EVALUATION OF AN EXPERIMENTAL APPROACH

EPA Science Inventory

Most solid-phase sediment toxicity identification and evaluation (TIE) techniques for organic chemicals have been focused on solid phase sorptive techniques, such as amending contaminated sediments with the carbonaceous resin, Ambersorb, coconut charcoal, or XAD resin to reduce t...

Sub-acute toxicity of cultured mycelia of himalayan entomogenous fungus Cordyceps sinensis (Berk.) Sacc. in rats.

PubMed

Meena, Harsahay; Singh, Kshetra Pal; Negi, Prem Sing; Ahmed, Zakwan

2013-05-01

Oral administration of laboratory cultured mycelia powder of C. sinensis did not show any sign of toxicity as no significant change was observed in organ weight and serological parameters in rats. However, there was a significant increase in food intake, body weight gain and hematological parameters like WBC, RBC, Hb and lymphocytes in treated groups. Histopathology of vital organs also supported the non toxic effect of C. sinensis. The results conclude that laboratory cultured mycelia powder of C. sinensis is safe and non toxic up to 2 g/kg body weight dose.

The deep permafrost carbon pool of the Yedoma region in Siberia and Alaska

PubMed Central

Strauss, Jens; Schirrmeister, Lutz; Grosse, Guido; Wetterich, Sebastian; Ulrich, Mathias; Herzschuh, Ulrike; Hubberten, Hans-Wolfgang

2013-01-01

[1] Estimates for circumpolar permafrost organic carbon (OC) storage suggest that this pool contains twice the amount of current atmospheric carbon. The Yedoma region sequestered substantial quantities of OC and is unique because its deep OC, which was incorporated into permafrost during ice age conditions. Rapid inclusion of labile organic matter into permafrost halted decomposition and resulted in a deep long-term sink. We show that the deep frozen OC in the Yedoma region consists of two distinct major subreservoirs: Yedoma deposits (late Pleistocene ice- and organic-rich silty sediments) and deposits formed in thaw-lake basins (generalized as thermokarst deposits). We quantified the OC pool based on field data and extrapolation using geospatial data sets to 83 + 61/−57 Gt for Yedoma deposits and to 128 + 99/−96 Gt for thermokarst deposits. The total Yedoma region 211 + 160/−153 Gt is a substantial amount of thaw-vulnerable OC that must be accounted for in global models. PMID:26074633

Ideas and perspectives: hydrothermally driven redistribution and sequestration of early Archaean biomass - the "hydrothermal pump hypothesis"

NASA Astrophysics Data System (ADS)

Duda, Jan-Peter; Thiel, Volker; Bauersachs, Thorsten; Mißbach, Helge; Reinhardt, Manuel; Schäfer, Nadine; Van Kranendonk, Martin J.; Reitner, Joachim

2018-03-01

Archaean hydrothermal chert veins commonly contain abundant organic carbon of uncertain origin (abiotic vs. biotic). In this study, we analysed kerogen contained in a hydrothermal chert vein from the ca. 3.5 Ga Dresser Formation (Pilbara Craton, Western Australia). Catalytic hydropyrolysis (HyPy) of this kerogen yielded n-alkanes up to n-C22, with a sharp decrease in abundance beyond n-C18. This distribution ( ≤ n-C18) is very similar to that observed in HyPy products of recent bacterial biomass, which was used as reference material, whereas it differs markedly from the unimodal distribution of abiotic compounds experimentally formed via Fischer-Tropsch-type synthesis. We therefore propose that the organic matter in the Archaean chert veins has a primarily microbial origin. The microbially derived organic matter accumulated in anoxic aquatic (surface and/or subsurface) environments and was then assimilated, redistributed and sequestered by the hydrothermal fluids (hydrothermal pump hypothesis).

Integrated mangrove-shrimp cultivation: Potential for blue carbon sequestration.

PubMed

Ahmed, Nesar; Thompson, Shirley; Glaser, Marion

2018-05-01

Globally, shrimp farming has had devastating effects on mangrove forests. However, mangroves are the most carbon-rich forests, with blue carbon (i.e., carbon in coastal and marine ecosystems) emissions seriously augmented due to devastating effects on mangrove forests. Nevertheless, integrated mangrove-shrimp cultivation has emerged as a part of the potential solution to blue carbon emissions. Integrated mangrove-shrimp farming is also known as organic aquaculture if deforested mangrove area does not exceed 50% of the total farm area. Mangrove destruction is not permitted in organic aquaculture and the former mangrove area in parts of the shrimp farm shall be reforested to at least 50% during a period of maximum 5 years according to Naturland organic aquaculture standards. This article reviews integrated mangrove-shrimp cultivation that can help to sequester blue carbon through mangrove restoration, which can be an option for climate change mitigation. However, the adoption of integrated mangrove-shrimp cultivation could face several challenges that need to be addressed in order to realize substantial benefits from blue carbon sequestration.

Packaging-induced failure of semiconductor lasers and optical telecommunications components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharps, J.A.

1996-12-31

Telecommunications equipment for field deployment generally have specified lifetimes of > 100,000 hr. To achieve this high reliability, it is common practice to package sensitive components in hermetic, inert gas environments. The intent is to protect components from particulate and organic contamination, oxidation, and moisture. However, for high power density 980 nm diode lasers used in optical amplifiers, the authors found that hermetic, inert gas packaging induced a failure mode not observed in similar, unpackaged lasers. They refer to this failure mode as packaging-induced failure, or PIF. PIF is caused by nanomole amounts of organic contamination which interact with highmore » intensity 980 nm light to form solid deposits over the emitting regions of the lasers. These deposits absorb 980 nm light, causing heating of the laser, narrowing of the band gap, and eventual thermal runaway. The authors have found PIF is averted by packaging with free O{sub 2} and/or a getter material that sequesters organics.« less

TOXICITY OF SILVER NANOPARTICLES TO DAPHNIA MAGNA

EPA Science Inventory

Relatively little is known regarding toxicity of nanoparticles in the environment. It is widely assumed that the toxicity of nanoparticles will be less than that of their metallic ions. Also the effect of organics on metal toxicity is well established. Presented here are the resu...

Review of the Toxicity of the Metallic Compounds Proposed for Use in the New Green Missile Formulation

NASA Technical Reports Server (NTRS)

Major, Michael A.

2000-01-01

In an effort to modernize and minimize hazards posed by the toxic components of missile propellant, the USACHPPM has been tasked to provide a comparison of the toxicity of compounds currently in use as missile propellants and the suite of compounds proposed to replace them. This report deals with the portion of this work concerning the toxicity of the organometallic compounds used in these formulations. Toxicity assessments of the organic compounds used in these formulations are published elsewhere. In general, toxicity data were available for all the metal compounds of concern or for closely related compounds that can serve as surrogates for the assessment of toxicity. We have high confidence in the reliability of these comparisons. This report is organized by element to provide the reader with an in-depth assessment with a minimum of redundancy. The narrative will first describe general concepts about the toxicity of each metal and then provide a summary of the toxicological information available for the specific compound.

The interactive effects of essential ions and salinity on the survival of Mysidopsis bahia in 96-H acute toxicity tests of effluents discharged to marine and estuarine receiving waters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Douglas, W.S.; Horne, M.T.

1997-10-01

The importance of salinity in whole effluent toxicity tests using marine organisms has been acknowledged in most testing protocols. However, little if any attention has been given to the specific effects of alteration of the ionic composition of seawater solutions to the test organism. The presence of persistent toxicity in effluents with no apparent toxic agents prompted examination of the potential influence of essential ions on the survival of the opossum shrimp, Mysidopsis bahia, a common effluent toxicity indicator organism. Through stepwise additions of ionic salts to deionized water, the minimum complement of salts to maintain survival of M. bahiamore » during 96-h exposures was determined to be Ca, Mg, K, Br, Na, and Cl. The toxicity curves for Ca, Mg, K, and Br were then determined across test salinity ranging from 10 to 35 parts per thousand. These curves for Ca, Mg, and K revealed that there are significant negative effects on survival when the essential ions are present in either low or high concentrations relative to the levels in natural seawater. Although there were no statistically detectable effects of Br on organism survival over the concentration range tested (5--480 mg/L). Br toxicity at concentrations less than 5 mg/L and greater than 700 mg/L have been shown in other studies. In addition, the tolerance ranges for K, Ca, and Mg were shown to shift significantly with changes in salinity, with lower salinity causing an apparent decrease in tolerance to an excess of essential ions. Tests with toxic effluents from five industrial and municipal sources revealed that adjustment of the ionic balance prior to testing reduced or eliminated toxicity in four of the five whole effluents tested. Suggestions for integrating this information into biomonitoring programs and toxicity identification evaluations are presented.« less

The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae

PubMed Central

Zhang, Weicheng; Bao, Shaopan; Fang, Tao

2016-01-01

Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te (particle) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs’ nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te (particle) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te (ion) efficiently determined the NPs toxicity associated with released ions. PMID:27094203

The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae

NASA Astrophysics Data System (ADS)

Zhang, Weicheng; Bao, Shaopan; Fang, Tao

2016-04-01

Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te (particle) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs’ nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te (particle) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te (ion) efficiently determined the NPs toxicity associated with released ions.

The neglected nano-specific toxicity of ZnO nanoparticles in the yeast Saccharomyces cerevisiae.

PubMed

Zhang, Weicheng; Bao, Shaopan; Fang, Tao

2016-04-20

Nanoparticles (NPs) with unique physicochemical properties induce nano-specific (excess) toxicity in organisms compared with their bulk counterparts. Evaluation and consideration of nano-specific toxicity are meaningful for the safe design and environmental risk assessment of NPs. However, ZnO NPs have been reported to lack excess toxicity for diverse organisms. In the present study, the nano-specific toxicity of ZnO NPs was evaluated in the yeast Saccharomyces cerevisiae. Nano-specific toxicity of ZnO NPs was not observed in the wild type yeast. However, the ZnO NPs induced very similar nano-specific toxicities in the three mutants with comparable log Te ((particle)) values (0.64 vs 0.65 vs 0.62), suggesting that the mutants were more sensitive and specific for the NPs' nano-specific toxicity. The toxic effects in the yeast were slightly attributable to dissolved zinc ions from the ZnO (nano or bulk) particles. Oxidative damage and mechanical damage contributed to the toxic effect of the ZnO particles. The mechanism of mechanical damage is proposed to be an inherent characteristic underlying the nano-specific toxicity in the mutants. The log Te ((particle)) was a useful parameter for evaluation of NPs nano-specific toxicity, whereas log Te ((ion)) efficiently determined the NPs toxicity associated with released ions.

Toxicity of Cúspide 480SL® spray mixture formulation of glyphosate to aquatic organisms.

PubMed

Currie, Zachary; Prosser, Ryan S; Rodriguez-Gil, Jose Luis; Mahon, Kim; Poirier, Dave; Solomon, Keith R

2015-05-01

In 2011, an alternative formulation of glyphosate (Cúspide 480SL®) was chosen to replace Roundup-SL®, Fuete-SL®, and Gly-41® for the control of Erythroxylum coca, the source of cocaine, in Colombia. Cúspide 480SL contains the active ingredient glyphosate isopropylamine (IPA) salt, which is the same active ingredient used in previous formulations. However, Cúspide 480SL contains an alkyl polyglycoside surfactant rather than the polyethoxylated tallow amine (POEA) surfactant used in other formulations and known to be more toxic to nonprimary producing aquatic organisms than glyphosate itself. An adjuvant, Cosmo-Flux F411, and water also are added to the spray mixture before application. Aquatic ecosystems adjacent to the target coca fields might be exposed to the spray mix, placing aquatic organisms at risk. Because no toxicity data were available for spray mixture on aquatic organisms, acute toxicity tests were conducted on aquatic plants, invertebrates, and fish, by using the Cúspide 480SL spray mix as described on the label. Based on the median effective concentration (EC50) values for similar organisms, the spray mixture was less toxic to aquatic organisms than formulations previously used for the control of coca (i.e., Roundup-SL, Fuete-SL, and Gly-41). A physical effect induced by Cosmo-Flux F411 was observed in Daphnia magna, Ceriodaphnia dubia, and Hyalella azteca, causing the invertebrates to be trapped in an oily film that was present at the surface of the water. However, a hazard assessment for the Cúspide 480SL spray mix, using estimated worst-case exposure scenario concentrations and EC50 values from the toxicity tests, indicated de minimis hazard for the tested aquatic animals, with hazard quotients all <1. © 2015 SETAC.

Determination of biodegradability kinetics of RCRA compounds using respirometry for structure-activity relationships

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tabak, H.H.; Desai, S.; Govind, R.

1990-01-01

Electrolytic respirometry is attaining prominence in biodegradation studies and is becoming one of the more suitable experimental methods for measuring the biodegradability and the kinetics of biodegradation of toxic organic compounds by the sewage, sludge, and soil microbiota and for determining substrate inhibitory effects to microorganisms in wastewater treatment systems. The purpose of the study was to obtain information on biological treatability of the benzene, phenol, phthalate, ketone organics and of the Superfund CERCLA organics bearing wastes in wastewater treatment systems which will support the development of an EPA technical guidance document on the discharge of the above organics tomore » POTWs. The paper discusses the experimental design and procedural steps for the respirometric biodegradation and toxicity testing approach for individual organics or specific industrial wastes at different concentration levels in a mineral salts medium. A developed multi-level protocol is presented for determination of the biodegradability, microbial acclimation to toxic substrates and first order kinetic parameters of biodegradation for estimation of the Monod kinetic parameter of toxic organic compounds, in order to correlate the extent and rate of biodegradation with a predictive model based on chemical properties and molecular structure of these compounds. Respirometric biodegradation/inhibition and biokinetic data are provided for representative RCRA alkyl benzene and ketone organics.« less

Bioavailability of Heavy Metals in Soil: Impact on Microbial Biodegradation of Organic Compounds and Possible Improvement Strategies

PubMed Central

Olaniran, Ademola O.; Balgobind, Adhika; Pillay, Balakrishna

2013-01-01

Co-contamination of the environment with toxic chlorinated organic and heavy metal pollutants is one of the major problems facing industrialized nations today. Heavy metals may inhibit biodegradation of chlorinated organics by interacting with enzymes directly involved in biodegradation or those involved in general metabolism. Predictions of metal toxicity effects on organic pollutant biodegradation in co-contaminated soil and water environments is difficult since heavy metals may be present in a variety of chemical and physical forms. Recent advances in bioremediation of co-contaminated environments have focussed on the use of metal-resistant bacteria (cell and gene bioaugmentation), treatment amendments, clay minerals and chelating agents to reduce bioavailable heavy metal concentrations. Phytoremediation has also shown promise as an emerging alternative clean-up technology for co-contaminated environments. However, despite various investigations, in both aerobic and anaerobic systems, demonstrating that metal toxicity hampers the biodegradation of the organic component, a paucity of information exists in this area of research. Therefore, in this review, we discuss the problems associated with the degradation of chlorinated organics in co-contaminated environments, owing to metal toxicity and shed light on possible improvement strategies for effective bioremediation of sites co-contaminated with chlorinated organic compounds and heavy metals. PMID:23676353

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

The Voluntary Reporting of Greenhouse Gases Program, required by Section 1605(b) of the Energy Policy Act of 1992, records the results of voluntary measures to reduce, avoid, or sequester greenhouse gas emissions. In 1998, 156 US companies and other organizations reported to the Energy information Administration that, during 1997, they had achieved greenhouse gas emission reductions and carbon sequestration equivalent to 166 million tons of carbon dioxide, or about 2.5% of total US emissions for the year. For the 1,229 emission reduction projects reported, reductions usually were measured by comparing an estimate of actual emissions with an estimate of whatmore » emissions would have been had the project not been implemented.« less

Bioengineered Chimeric Spider Silk-Uranium Binding Proteins

PubMed Central

Krishnaji, Sreevidhya Tarakkad; Kaplan, David L.

2014-01-01

Heavy metals constitute a source of environmental pollution. Here, novel functional hybrid biomaterials for specific interactions with heavy metals are designed by bioengineering consensus sequence repeats from spider silk of Nephila clavipes with repeats of a uranium peptide recognition motif from a mutated 33-residue of calmodulin protein from Paramecium tetraurelia. The self-assembly features of the silk to control nanoscale organic/inorganic material interfaces provides new biomaterials for uranium recovery. With subsequent enzymatic digestion of the silk to concentrate the sequestered metals, options can be envisaged to use these new chimeric protein systems in environmental engineering, including to remediate environments contaminated by uranium. PMID:23212989

Sequestration of carbon in soil organic matter in Senegal: an overview

USGS Publications Warehouse

Tieszen, Larry L.; Tappan, G. Gray; Toure, A.

2004-01-01

The project focuses on four objectives in specific locations across the agroecological zones of Senegal. These objectives are: use of soil sampling and biogeochemical modeling to quantify the biophysical potential for carbon sequestration and to determine the sensitivity of the carbon stocks to various management and climate scenarios, to evaluate the socio-economic and cultural requirements necessary for successful project implementation directed toward an aggregation of smallholders to sequester around 100,000 t carbon (C), to support capacity building to develop a Carbon Specialist Team, and to initiate extrapolation from site-specific project areas to the Sahel region and the national level.

Tracking the rise of eukaryotes to ecological dominance with zinc isotopes.

PubMed

Isson, Terry T; Love, Gordon D; Dupont, Christopher L; Reinhard, Christopher T; Zumberge, Alex J; Asael, Dan; Gueguen, Bleuenn; McCrow, John; Gill, Ben C; Owens, Jeremy; Rainbird, Robert H; Rooney, Alan D; Zhao, Ming-Yu; Stueeken, Eva E; Konhauser, Kurt O; John, Seth G; Lyons, Timothy W; Planavsky, Noah J

2018-06-05

The biogeochemical cycling of zinc (Zn) is intimately coupled with organic carbon in the ocean. Based on an extensive new sedimentary Zn isotope record across Earth's history, we provide evidence for a fundamental shift in the marine Zn cycle ~800 million years ago. We discuss a wide range of potential drivers for this transition and propose that, within available constraints, a restructuring of marine ecosystems is the most parsimonious explanation for this shift. Using a global isotope mass balance approach, we show that a change in the organic Zn/C ratio is required to account for observed Zn isotope trends through time. Given the higher affinity of eukaryotes for Zn relative to prokaryotes, we suggest that a shift toward a more eukaryote-rich ecosystem could have provided a means of more efficiently sequestering organic-derived Zn. Despite the much earlier appearance of eukaryotes in the microfossil record (~1700 to 1600 million years ago), our data suggest a delayed rise to ecological prominence during the Neoproterozoic, consistent with the currently accepted organic biomarker records. © 2018 John Wiley & Sons Ltd.

Toxicity of fire retardant chemicals to aquatic organisms: Progress report

USGS Publications Warehouse

Hamilton, Steven J.; McDonald, Susan F.; Gaikowski, Mark P.; Buhl, Kevin J.; Ramsey, G.S.

1996-01-01

Fire retardants and suppressants used extensively in North America are often applied in environmentally sensitive areas that may contain endangered, threatened, or economically important plant and animal species. We conducted laboratory acute toxicity tests in both hard and soft waters with five commonly used fire control chemicals (Fire Trol LCG-R, Fire-Trol GTS-R, Phos-Chek D-75-F, Phos-Chek WD-881, and Silv-Ex). Organisms used in the tests included two fish (rainbow trout and fathead minnow), two aquatic invertebrates (Daphnia magna and Hyalella azteca), and a green algae (Selenastrum capricornutum). In general, the green algae was substantially more sensitive to the three non-foam fire chemicals than the animals, the Daphnia were the most sensitive test organism in exposures with foams. The two foams (Silv-Ex and Phos-Chek WD-881) had similar toxicity and were more toxic than the three non-foams. Water quality did not seem to modify the toxicity of the five fire chemicals in a consistent manner.

DOE Office of Scientific and Technical Information (OSTI.GOV)

van Gestel, C.A.; Ma, W.C.

The acute toxicity of five chlorophenols for two earthworm species was determined in two sandy soils differing in organic matter content and the results were compared with adsorption data. Adsorption increased with increasing organic matter content of the soils, but for tetra- and pentachlorophenol was also influenced by soil pH. Earthworm toxicity was significantly higher in the soil with a low level of organic matter. This difference disappeared when LC50 values were recalculated to concentrations in soil solution using adsorption data. Eisenia fetida andrei showed LC50 values lower than those of Lumbricus rubellus although bioaccumulation was generally higher in themore » latter species. Toxicity and bioaccumulation based on soil solution concentrations increased with increasing lipophilicity of the chlorophenols. The present results indicate that the toxicity and bioaccumulation and therefore the bioavailability of chlorophenols in soil to earthworms are dependent on the concentration in soil solution and can be predicted on the basis of adsorption data. Both the toxicity of and bioaccumulation data on chlorophenols in earthworms demonstrated surprisingly good agreement with those on chlorophenols in fish.« less

Whole Effluent Toxicity (WET)

EPA Pesticide Factsheets

Whole Effluent Toxicity (WET) describes the aggregate toxic effect of an aqueous sample (e.g., whole effluent wastewater discharge) as measured by an organism's response upon exposure to the sample (e.g., lethality, impaired growth, or reproduction).

TARGET ORGAN TOXICITY IN MARINE AND FRESHWATER TELEOSTS: VOLUME 1 - ORGANS

EPA Science Inventory

In any given aquatic ecosystem, fish serve a multitude of critical functions and so, are typically included in the risk assessment of various chemicals in waterways. However, uncertainties in toxicity evaluation can arise since these assessments are usually based solely on acute ...

40 CFR 469.13 - Monitoring.

Code of Federal Regulations, 2011 CFR

2011-07-01

... ELECTRICAL AND ELECTRONIC COMPONENTS POINT SOURCE CATEGORY Semiconductor Subcategory § 469.13 Monitoring. (a... with the permit limitation for total toxic organics (TTO), I certify that, to the best of my knowledge and belief, no dumping of concentrated toxic organics into the wastewaters has occurred since filing...

Toxicity, Bioaccumulation and Biotransformation of Silver Nanoparticles in Marine Organisms

EPA Science Inventory

The toxicity, bioaccumulation and biotransformation of citrate and polyvinylpyrrolidone (PVP) capped silver nanoparticles (NPs) (AgNP-citrate and AgNP-PVP) and titanium dioxide (TiO2) NPs in marine organisms via marine sediment exposure were investigated. Results from 7-d sedimen...

Sensing and capture of toxic and hazardous gases and vapors by metal-organic frameworks.

PubMed

Wang, Hao; Lustig, William P; Li, Jing

2018-03-13

Toxic and hazardous chemical species are ubiquitous, predominantly emitted by anthropogenic activities, and pose serious risks to human health and the environment. Thus, the sensing and subsequent capture of these chemicals, especially in the gas or vapor phase, are of extreme importance. To this end, metal-organic frameworks have attracted significant interest, as their high porosity and wide tunability make them ideal for both applications. These tailorable framework materials are particularly promising for the specific sensing and capture of targeted chemicals, as they can be designed to fit a diverse range of required conditions. This review will discuss the advantages of metal-organic frameworks in the sensing and capture of harmful gases and vapors, as well as principles and strategies guiding the design of these materials. Recent progress in the luminescent detection of aromatic and aliphatic volatile organic compounds, toxic gases, and chemical warfare agents will be summarized, and the adsorptive removal of fluorocarbons/chlorofluorocarbons, volatile radioactive species, toxic industrial gases and chemical warfare agents will be discussed.

Toxicity and biodegradability of high strength/toxic organic liquid industrial effluents and hazardous landfill leachates.

PubMed

Naidoo, V; du Preez, M; Rakgotho, T; Odhav, B; Buckley, C A

2002-01-01

Industrial effluents and leachates from hazardous landfill sites were tested for toxicity using the anaerobic toxicity assay. This test was done on several industrial effluents (brewery spent grain effluent, a chemical industry effluent, size effluent), and several hazardous landfill leachates giving vastly different toxicity results. The brewery effluent, spent grain effluent and size effluent were found to be less toxic than the chemical effluent and hazardous landfill leachate samples. The chemical industry effluent was found to be most toxic. Leachate samples from the H:h classified hazardous landfill site were found to be less toxic at high concentrations (40% (v/v)) while the H:H hazardous landfill leachate samples were found to be more toxic even at low concentrations of 4% (v/v). The 30 d biochemical methane potential tests revealed that the brewery effluent, organic spent grain effluent and size effluent were 89%, 63%, and 68% biodegradable, respectively. The leachate from Holfontein hazardous landfill site was least biodegradable (19%) while the chemical effluent and Aloes leachate were 29% and 32% biodegradable under anaerobic conditions.

Toxicity of trace element and salinity mixtures to striped bass (Morone saxatilis) and Daphnia magna

USGS Publications Warehouse

Dwyer, F.J.; Burch, S.A.; Ingersoll, C.G.; Hunn, J.B.

1992-01-01

Acute toxicity tests with reconstituted water were conducted to investigate the relationship between water hardness, salinity, and a mixture of trace elements found in irrigation drain waters entering Stillwater Wildlife Management Area (SWMA), near Fallon, Nevada. The SWMA has been the site of many fish kills in recent years, and previous toxicity studies indicated that one drain water, Pintail Bay, was acutely toxic to organisms acclimated or cultured in fresh water or salt water. This toxicity could reflect both the ionic composition of this saline water and the presence of trace elements. The lowest water salinity tested with Daphnia magna was near the upper salinity tolerance of these organisms; therefore, we were unable to differentiate between the toxic effects of ion composition and those of trace elements. In toxicity tests conducted with striped bass (Morone saxatilis), we found that the extent to which salinity was lethal to striped bass depended on the ion composition of that salinity. Survival of striped bass increased as hardness increased. In addition, a trace element mixture was toxic to striped bass, even though the concentrations of individual elements were below expected acutely lethal concentrations. Although salinity is an important water quality characteristic, the ionic composition of the water must be considered when one assesses the hazard of irrigation drain waters to aquatic organisms.

Toxicology of organic-inorganic hybrid molecules: bio-organometallics and its toxicology.

PubMed

Fujie, Tomoya; Hara, Takato; Kaji, Toshiyuki

2016-01-01

Bio-organometallics is a research strategy of biology that uses organic-inorganic hybrid molecules. The molecules are expected to exhibit useful bioactivities based on the unique structure formed by interaction between the organic structure and intramolecular metal(s). However, studies on both biology and toxicology of organic-inorganic hybrid molecules have been incompletely performed. There can be two types of toxicological studies of bio-organometallics; one is evaluation of organic-inorganic hybrid molecules and the other is analysis of biological systems from the viewpoint of toxicology using organic-inorganic hybrid molecules. Our recent studies indicate that cytotoxicity of hybrid molecules containing a metal that is nontoxic in inorganic forms can be more toxic than that of hybrid molecules containing a metal that is toxic in inorganic forms when the structure of the ligand is the same. Additionally, it was revealed that organic-inorganic hybrid molecules are useful for analysis of biological systems important for understanding the toxicity of chemical compounds including heavy metals.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amacher, David E.

Biomarkers are biometric measurements that provide critical quantitative information about the biological condition of the animal or individual being tested. In drug safety studies, established toxicity biomarkers are used along with other conventional study data to determine dose-limiting organ toxicity, and to define species sensitivity for new chemical entities intended for possible use as human medicines. A continuing goal of drug safety scientists in the pharmaceutical industry is to discover and develop better trans-species biomarkers that can be used to determine target organ toxicities for preclinical species in short-term studies at dose levels that are some multiple of the intendedmore » human dose and again later in full development for monitoring clinical trials at lower therapeutic doses. Of particular value are early, predictive, noninvasive biomarkers that have in vitro, in vivo, and clinical transferability. Such translational biomarkers bridge animal testing used in preclinical science and human studies that are part of subsequent clinical testing. Although suitable for in vivo preclinical regulatory studies, conventional hepatic safety biomarkers are basically confirmatory markers because they signal organ toxicity after some pathological damage has occurred, and are therefore not well-suited for short-term, predictive screening assays early in the discovery-to-development progression of new chemical entities (NCEs) available in limited quantities. Efforts between regulatory agencies and the pharmaceutical industry are underway for the coordinated discovery, qualification, verification and validation of early predictive toxicity biomarkers. Early predictive safety biomarkers are those that are detectable and quantifiable prior to the onset of irreversible tissue injury and which are associated with a mechanism of action relevant to a specific type of potential hepatic injury. Potential drug toxicity biomarkers are typically endogenous macromolecules in biological fluids with varying immunoreactivity which can present bioanalytical challenges when first discovered. The potential success of these efforts is greatly enhanced by recent advances in two closely linked technologies, toxicoproteomics and targeted, quantitative mass spectrometry. This review focuses on the examination of the current status of these technologies as they relate to the discovery and development of novel preclinical biomarkers of hepatotoxicity. A critical assessment of the current literature reveals two distinct lines of safety biomarker investigation, (1) peripheral fluid biomarkers of organ toxicity and (2) tissue or cell-based toxicity signatures. Improved peripheral fluid biomarkers should allow the sensitive detection of potential organ toxicity prior to the onset of overt organ pathology. Advancements in tissue or cell-based toxicity biomarkers will provide sensitive in vitro or ex vivo screening systems based on toxicity pathway markers. An examination of the current practices in clinical pathology and the critical evaluation of some recently proposed biomarker candidates in comparison to the desired characteristics of an ideal toxicity biomarker lead this author to conclude that a combination of selected biomarkers will be more informative if not predictive of potential animal organ toxicity than any single biomarker, new or old. For the practical assessment of combinations of conventional and/or novel toxicity biomarkers in rodent and large animal preclinical species, mass spectrometry has emerged as the premier analytical tool compared to specific immunoassays or functional assays. Selected and multiple reaction monitoring mass spectrometry applications make it possible for this same basic technology to be used in the progressive stages of biomarker discovery, development, and more importantly, routine study applications without the use of specific antibody reagents. This technology combined with other 'omics' technologies can provide added selectivity and sensitivity in preclinical drug safety testing.« less

A Novel Approach for Predicting Sublethal Effects of Toxicants to Aquatic Organisms

DTIC Science & Technology

1984-11-30

sublethal levels of copper. Overall, WSF P JP-4 appears to affect osmoregulation and liver function. These effects were much more pronounced in fish...i "-’p WOSR.TR. .0 8 Lfl SA NOVEL APPROACH FOR PREDICTING SUBLETHAL EFFECTS OF SI TOXICANTS TO AQUATIC ORGANISMS FINAL SCIENTIFIC REPORT GRANT AFOSR...alan A Novel Approach for �F 2312 AS JPredicting Sublethal Effects of Tbxicants to Aymtic- 12. PERIISONAL AUTHORIS) OrganISMS -Cairns, J.,-Jr

Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

USGS Publications Warehouse

Johnson, W. Waynon; Finley, Mack T.

1980-01-01

Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates.The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies.Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978a).The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data from the Columbia Laboratory and its field laboratories. It presents definitive acute toxicity data on 271 chemicals tested against a variety of freshwater invertebrates and fishes. The chemicals represent all major groups of pesticides, as well as numerous industrial chemicals. This compilation should serve as a useful database for the many agencies and organizations dealing with research and management programs concerned with the impact of chemicals on aquatic resources.The Columbia Laboratory has played a major role in developing currently used standard methodology for static acute toxicity testing. The use of standardized methodology greatly reduces variation in results. The data presented here have been carefully scrutinized to eliminate tests that failed to follow acceptable procedures. Handling of test organisms and procedures for static toxicity tests followed those described by Lennon and Walker (1964) and Macek and McAllister (1970), and conform well with those recommended by Brauhn and Schoettger (1975) and the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975).The species of fish and invertebrates that were tested are listed in phylogenetic order in Tables 1 and 2. Fish were obtained from Federal and State hatcheries as either eggs or fry. Original stocks of invertebrates were collected and cultured from wild populations with no known source of contamination; these populations were replenished regularly. The invertebrates were cultured in the Laboratory by methods similar to those described by Sanders and Cope (1966).Test chemicals usually consisted of technical or analytical grade samples of known purity. Formulations of the chemicals were also tested when available. When purity of test chemicals was known, all calculated concentrations were based on percent active ingredients. Stock solutions were prepared immediately before each test, with commercial grade acetone as the carrier solvent. Occasionally, ethanol or dimethyl-formamide was substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water.Test water (dilution water) was reconstituted from deionized water of at least 106 ohms resistivity by the addition of appropriate reagent grade chemicals (Marking 1969). Water was buffered to maintain a pH of 7.2 to 7.5, an alkalinity of 30 to 35 mg/L, and a hardness of 40 to 50 mg/L as CaCO3. Test water was mixed thoroughly and aerated before transfer into test chambers. Fish were acclimated to dilution water by gradually changing the water in acclimated tanks from 100% well water to 100% reconstituted water over a 1- to 3-day period at the desired testing temperature. Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Toxicity tests were conducted under static conditions without aeration, and the organisms were not fed during acclimation or testing. Temperature of test solutions was maintained within ± 1°C of that required for a given test.Toxicity tests with fish were conducted in 18.9-liter (5-gal) wide-mouthed jars containing 15 liters of test solution. Fingerling fish weighing 0.2 to 1.5 g were tested at each concentration. Caution was taken not to exceed 0.8 g of test organisms per liter of solution. Duplicate test chambers were used to accommodate larger fish. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. At least six concentrations were used per toxicity test.The tests began upon initial exposure to the toxicant and continued for 96 h. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber were recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times.Toxicity data were analyzed by a statistical method described by Litchfield and Wilcoxon (1949) to determine LC50 (theoretical estimate of the concentration lethal to 50% of the test animals) and 95% confidence intervals. This method is recommended by the American Public Health Association (1971) and by Sprague (1969) for determining median lethal concentrations. The procedure is easily modified for computing a single LC50 when replicate tests are performed.

Effect of AL2O3 and TiO2 nanoparticles on aquatic organisms

NASA Astrophysics Data System (ADS)

Gosteva, I.; Morgalev, Yu; Morgaleva, T.; Morgalev, S.

2015-11-01

Environmental toxicity of aqueous disperse systems of nanoparticles of binary compounds of titanium dioxides (with particle size Δ50=5 nm, Δ50=50 nm, Δ50=90 nm), aluminum oxide alpha-forms (Δ50=7 nm and Δ50=70 nm) and macro forms (TiO2 Δ50=350 nm, Al2O3 A50=4000 nm) were studied using biological testing methods. The bioassay was performed using a set of test organisms representing the major trophic levels. We found the dependence of the toxic effect concentration degree of nTiO2 and nAl2O3 on the fluorescence of the bacterial biosensor "Ekolyum", the chemotactic response of ciliates Paramecium caudatum, the growth of unicellular algae Chlorella vulgaris Beijer and mortality of entomostracans Daphnia magna Straus. We revealed the selective dependence of nTiO2 and nAl2O3 toxicity on the size, concentration and chemical nature of nanoparticles. The minimal concentration causing an organism's response on nTiO2 and nAl2O3 effect depends on the type of the test- organism and the test reaction under study. We specified L(E)C50 and acute toxicity categories for all the studied nanoparticles. We determined that nTiO2 (Δ50=5 nm) belong to the category «Acute toxicity 1», nTiO2 (A50=90 nm) and nAl2O3 (Δ50=70 nm) - to the category «Acute toxicity 2», nAl2O3 (Δ50=7 nm) - to the category «Acute toxicity 3». No acute toxicity was registered for nTiO2 (Δ50=50 nm) and macro form TiO2.

Application of a battery of biotests for the determination of leachate toxicity to bacteria and invertebrates from sewage sludge-amended soil.

PubMed

Malara, Anna; Oleszczuk, Patryk

2013-05-01

The objective of the study was to determine the leachates toxicity from sewage sludge-amended soils (sandy and loamy). Samples originated from a plot experiment realized over a period of 29 months. Two types of soil were fertilized with sewage sludges at the dose of 3 % (90 t/ha). Soil samples were taken after 0, 7, 17, and 29 months from the application of sewage sludges. Leachates were obtained according to the EN 12457-2 protocol. The following commercial tests were applied for the estimation of the toxicity: Microtox (Vibrio fischeri), Microbial assay for toxic risk assessment (ten bacteria and one yeast), Protoxkit F (Tetrahymena thermophila), Rotoxkit F (Brachionus calyciflorus), and Daphtoxkit F (Daphnia magna). The test organisms displayed varied toxicity with relation to the soils amended with sewage sludges. The toxicity of the leachates depended both on the soil type and on the kind of sewage sludge applied. Notable differences were also observed in the sensitivity of the test organisms to the presence of sewage sludge in the soil. The highest sensitivity was a characteristic of B. calyciflorus, while the lowest sensitivity to the presence of the sludges was revealed by the protozoa T. thermophila. Throughout the periods of the study, constant variations of toxicity were observed for most of the test organisms. The intensity as well as the range of those variations depended both on the kind of test organism and on the kind of sludge and soil type. In most cases, an increase of the toxicity of soils amended with the sewage sludges was observed after 29 months of the experiment.

Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments

USGS Publications Warehouse

Besser, J.M.; Brumbaugh, W.G.; May, T.W.; Ingersoll, C.G.

2003-01-01

We evaluated the partitioning and toxicity of cadmium (Cd) and copper (Cu) spiked into formulated sediments containing two types of organic matter (OM), i.e., cellulose and humus. Amendments of cellulose up to 12.5% total organic carbon (TOC) did not affect partitioning of Cd or Cu between sediment and pore water and did not significantly affect the toxicity of spiked sediments in acute toxicity tests with the amphipod Hyalella azteca. In contrast, amendments of natural humus shifted the partitioning of both Cd and Cu toward greater concentrations in sediment and lesser concentrations in pore water and significantly reduced toxic effects of both metals. Thresholds for toxicity, based on measured metal concentrations in whole sediment, were greater for both Cd and Cu in sediments amended with a low level of humus (2.9% TOC) than in sediments without added OM. Amendments with a high level of humus (8.9% TOC) eliminated toxicity at the highest spike concentrations of both metals (sediment concentrations of 12.4 ??g Cd/g and 493 ??g Cu/g). Concentrations of Cd in pore water associated with acute toxicity were similar between sediments with and without humus amendments, suggesting that toxicity of Cd was reduced primarily by sorption to sediment OM. However, toxic effects of Cu in humus treatments were associated with greater pore-water concentrations than in controls, suggesting that toxicity of Cu was reduced both by sorption and by complexation with soluble ligands. Both sorption and complexation by OM tend to make proposed sediment quality guidelines (SQGs) based on total metal concentrations more protective for high-OM sediments. Our results suggest that the predictive ability of SQGs could be improved by models of metal interactions with natural OM in sediment and pore water.

Effects of organic amendments on the toxicity and bioavailability of cadmium and copper in spiked formulated sediments.

PubMed

Besser, John M; Brumbaugh, William G; May, Thomas W; Ingersoll, Christopher G

2003-04-01

We evaluated the partitioning and toxicity of cadmium (Cd) and copper (Cu) spiked into formulated sediments containing two types of organic matter (OM), i.e., cellulose and humus. Amendments of cellulose up to 12.5% total organic carbon (TOC) did not affect partitioning of Cd or Cu between sediment and pore water and did not significantly affect the toxicity of spiked sediments in acute toxicity tests with the amphipod Hyalella azteca. In contrast, amendments of natural humus shifted the partitioning of hoth Cd and Cu toward greater concentrations in sediment and lesser concentrations in pore water and significantly reduced toxic effects of both metals. Thresholds for toxicity, based on measured metal concentrations in whole sediment, were greater for both Cd and Cu in sediments amended with a low level of humus (2.9% TOC) than in sediments without added OM. Amendments with a high level of humus (8.9% TOC) eliminated toxicity at the highest spike concentrations of both metals (sediment concentrations of 12.4 microg Cd/g and 493 microg Cu/g). Concentrations of Cd in pore water associated with acute toxicity were similar between sediments with and without humus amendments, suggesting that toxicity of Cd was reduced primarily by sorption to sediment OM. However, toxic effects of Cu in humus treatments were associated with greater pore-water concentrations than in controls, suggesting that toxicity of Cu was reduced both by sorption and by complexation with soluble ligands. Both sorption and complexation by OM tend to make proposed sediment quality guidelines (SQGs) based on total metal concentrations more protective for high-OM sediments. Our results suggest that the predictive ability of SQGs could be improved by models of metal interactions with natural OM in sediment and pore water.

Organic Matter Application Can Reduce Copper Toxicity in Tomato Plants

ERIC Educational Resources Information Center

Campbell, Brian

2010-01-01

Copper fungicides and bactericides are often used in tomato cultivation and can cause toxic Cu levels in soils. In order to combat this, organic matter can be applied to induce chelation reactions and form a soluble complex by which much of the Cu can leach out of the soil profile or be taken up safely by plants. Organic acids such as citric,…

Lactic Acid Bacteria Protects Caenorhabditis elegans from Toxicity of Graphene Oxide by Maintaining Normal Intestinal Permeability under different Genetic Backgrounds

NASA Astrophysics Data System (ADS)

Zhao, Yunli; Yu, Xiaoming; Jia, Ruhan; Yang, Ruilong; Rui, Qi; Wang, Dayong

2015-11-01

Lactic acid bacteria (LAB) is safe and useful for food and feed fermentation. We employed Caenorhabditis elegans to investigate the possible beneficial effect of LAB (Lactobacillus bulgaricus) pretreatment against toxicity of graphene oxide (GO) and the underlying mechanisms. LAB prevented GO toxicity on the functions of both primary and secondary targeted organs in wild-type nematodes. LAB blocked translocation of GO into secondary targeted organs through intestinal barrier by maintaining normal intestinal permeability in wild-type nematodes. Moreover, LAB prevented GO damage on the functions of both primary and secondary targeted organs in exposed nematodes with mutations of susceptible genes (sod-2, sod-3, gas-1, and aak-2) to GO toxicity by sustaining normal intestinal permeability. LAB also sustained the normal defecation behavior in both wild-type nematodes and nematodes with mutations of susceptible genes. Therefore, the beneficial role of LAB against GO toxicity under different genetic backgrounds may be due to the combinational effects on intestinal permeability and defecation behavior. Moreover, the beneficial effects of LAB against GO toxicity was dependent on the function of ACS-22, homologous to mammalian FATP4 to mammalian FATP4. Our study provides highlight on establishment of pharmacological strategy to protect intestinal barrier from toxicity of GO.

Toxicity of carbon nanotubes to freshwater aquatic invertebrates

USGS Publications Warehouse

Mwangi, Joseph N.; Wang, Ning; Ingersoll, Christopher G.; Hardesty, Doug K.; Brunson, Eric L.; Li, Hao; Deng, Baolin

2012-01-01

Carbon nanotubes (CNTs) are hydrophobic in nature and thus tend to accumulate in sediments if released into aquatic environments. As part of our overall effort to examine the toxicity of carbon-based nanomaterials to sediment-dwelling invertebrates, we have evaluated the toxicity of different types of CNTs in 14-d water-only exposures to an amphipod (Hyalella azteca), a midge (Chironomus dilutus), an oligochaete (Lumbriculus variegatus), and a mussel (Villosa iris) in advance of conducting whole-sediment toxicity tests with CNTs. The results of these toxicity tests conducted with CNTs added to water showed that 1.00g/L (dry wt) of commercial sources of CNTs significantly reduced the survival or growth of the invertebrates. Toxicity was influenced by the type and source of the CNTs, by whether the materials were precleaned by acid, by whether sonication was used to disperse the materials, and by species of the test organisms. Light and electron microscope imaging of the surviving test organisms showed the presence of CNTs in the gut as well as on the outer surface of the test organisms, although no evidence was observed to show penetration of CNTs through cell membranes. The present study demonstrated that both the metals solubilized from CNTs such as nickel and the "metal-free" CNTs contributed to the toxicity.

Effects of soil organic matter content on cadmium toxicity in Eisenia fetida: implications for the use of biomarkers and standard toxicity tests.

PubMed

Irizar, A; Rodríguez, M P; Izquierdo, A; Cancio, I; Marigómez, I; Soto, M

2015-01-01

Bioavailability is affected by soil physicochemical characteristics such as pH and organic matter (OM) content. In addition, OM constitutes the energy source of Eisenia fetida, a well established model species for soil toxicity assessment. The present work aimed at assessing the effects of changes in OM content on the toxicity of Cd in E. fetida through the measurement of neutral red uptake (NRU) and mortality, growth, and reproduction (Organisation for Economic Co-operation and Development [OECD] Nos. 207 and 222). Complementarily, metallothionein (MT) and catalase transcription levels were measured. To decrease variability inherent to natural soils, artificial soils (Organization for Economic Cooperation and Development 1984) with different OM content (6, 10, and 14%) and spiked with Cd solutions at increasing concentrations were used. Low OM in soil decreased soil ingestion and Cd bioaccumulation but also increased Cd toxicity causing lower NRU of coelomocytes, 100 % mortality, and stronger reproduction impairment, probably due to the lack of energy to maintain protection mechanisms (production of MT).Cd bioaccumulation did not reflect toxicity, and OM played a pivotal role in Cd toxicity. Thus, OM content should be taken into account when using E. fetida in in vivo exposures for soil health assessment.

Toxic effects of fluoride on organisms.

PubMed

Zuo, Huan; Chen, Liang; Kong, Ming; Qiu, Lipeng; Lü, Peng; Wu, Peng; Yang, Yanhua; Chen, Keping

2018-04-01

Accumulation of excess fluoride in the environment poses serious health risks to plants, animals, and humans. This endangers human health, affects organism growth and development, and negatively impacts the food chain, thereby affecting ecological balance. In recent years, numerous studies focused on the molecular mechanisms associated with fluoride toxicity. These studies have demonstrated that fluoride can induce oxidative stress, regulate intracellular redox homeostasis, and lead to mitochondrial damage, endoplasmic reticulum stress and alter gene expression. This paper reviews the present research on the potential adverse effects of overdose fluoride on various organisms and aims to improve our understanding of fluoride toxicity. Copyright © 2018 Elsevier Inc. All rights reserved.

A SURROGATE SUBCHRONIC TOXICITY TEST METHOD FOR WATERS WITH HIGH TOTAL DISSOLVED SOLIDS

EPA Science Inventory

Total dissolved solids (TDS) are often identified as a toxicant in whole-effluent toxicity (WET) testing. The primary test organism used in WET testing, Ceriodaphnia dubia, is very sensitive to TDS ions, which can be problematic when differentiating the toxicity of TDS from those...

What’s Causing Toxicity in Sediments? Results of Twenty Years of Toxicity Identification and Evaluations (TIEs)

EPA Science Inventory

Sediment Toxicity Identification and Evaluation (TIEs) methods have been used for twenty years to identify the causes of toxicity in sediments around the world. We summarized and categorized results of more than 80 peer-reviewed TIE studies into non-ionic organic, cationic, ammo...

ESTIMATION OF ACUTE TOXICITY BY FITTING A DOSE-TIME RESPONSE SURFACE

EPA Science Inventory

In acute toxicity testing, organisms are continuously exposed to progressively increasing concentrations of a chemical and deaths of test organisms are recorded at several selected times. he results of the test are traditionally summarized by a dose-response curve, and the time c...

EVALUATION OF MINIMUM DATA REQUIREMENTS FOR ACUTE TOXICITY VALUE EXTRAPOLATION WITH AQUATIC ORGANISMS

EPA Science Inventory

Buckler, Denny R., Foster L. Mayer, Mark R. Ellersieck and Amha Asfaw. 2003. Evaluation of Minimum Data Requirements for Acute Toxicity Value Extrapolation with Aquatic Organisms. EPA/600/R-03/104. U.S. Environmental Protection Agency, National Health and Environmental Effects Re...

40 CFR 469.12 - Specialized definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AND STANDARDS ELECTRICAL AND ELECTRONIC COMPONENTS POINT SOURCE CATEGORY Semiconductor Subcategory... in 40 CFR part 136 apply to this subpart. In addition, (a) The term “total toxic organics (TTO)” means the sum of the concentrations for each of the following toxic organic compounds which is found in...

40 CFR 469.12 - Specialized definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AND STANDARDS ELECTRICAL AND ELECTRONIC COMPONENTS POINT SOURCE CATEGORY Semiconductor Subcategory... in 40 CFR part 136 apply to this subpart. In addition, (a) The term “total toxic organics (TTO)” means the sum of the concentrations for each of the following toxic organic compounds which is found in...

APPARATUS FOR EXPOSING ESTUARINE AQUATIC ORGANISMS TO TOXICANTS IN CONSTANT AND FLUCTUATING SALINITY REGIMES

EPA Science Inventory

A programmable control system for salinity has been developed and coupled with a flow-through toxicant exposure system. The resulting apparatus allow study of influences of constant and fluctuating salinity regimes on responses of One organisms exposed to selected pollutants. Con...

RULES FOR DISTINGUISHING TOXICANTS THAT CAUSE TYPE (I) AND TYPE (II) NARCOSIS SYNDROMES

EPA Science Inventory

Narcosis is a non-specific reversible state of arrested activity of protoplasmic structures caused by a wide variety of organic chemicals. he vast majority of industrial organic chemicals can be characterized by a baseline structure-toxicity relationship as developed for diverse ...

COMPARATIVE TOXICITY TESTING OF SELECTED BENTHIC AND EPIBENTHIC ORGANISMS FOR THE DEVELOPMENT OF SEDIMENT QUALITY TEST PROTOCOLS

EPA Science Inventory

Sediment contamination has resulted in the need to develop an appropriate suite of toxicity tests to assess ecotoxicological impacts on estuarine ecosystems. Existing Environmental Protection Agency (EPA) protocols recommend a number of test organisms, including amphipods, polych...

MODELING THE FATE OF TOXIC ORGANIC MATERIALS IN AQUATIC ENVIRONMENTS

EPA Science Inventory

Documentation is given for PEST, a dynamic simulation model for evaluating the fate of toxic organic materials (TOM) in freshwater environments. PEST represents the time-varying concentration (in ppm) of a given TOM in each of as many as 16 carrier compartments; it also computes ...

High-Density Real-Time PCR-Based in Vivo Toxicogenomic Screen to Predict Organ-Specific Toxicity

PubMed Central

Fabian, Gabriella; Farago, Nora; Feher, Liliana Z.; Nagy, Lajos I.; Kulin, Sandor; Kitajka, Klara; Bito, Tamas; Tubak, Vilmos; Katona, Robert L.; Tiszlavicz, Laszlo; Puskas, Laszlo G.

2011-01-01

Toxicogenomics, based on the temporal effects of drugs on gene expression, is able to predict toxic effects earlier than traditional technologies by analyzing changes in genomic biomarkers that could precede subsequent protein translation and initiation of histological organ damage. In the present study our objective was to extend in vivo toxicogenomic screening from analyzing one or a few tissues to multiple organs, including heart, kidney, brain, liver and spleen. Nanocapillary quantitative real-time PCR (QRT-PCR) was used in the study, due to its higher throughput, sensitivity and reproducibility, and larger dynamic range compared to DNA microarray technologies. Based on previous data, 56 gene markers were selected coding for proteins with different functions, such as proteins for acute phase response, inflammation, oxidative stress, metabolic processes, heat-shock response, cell cycle/apoptosis regulation and enzymes which are involved in detoxification. Some of the marker genes are specific to certain organs, and some of them are general indicators of toxicity in multiple organs. Utility of the nanocapillary QRT-PCR platform was demonstrated by screening different references, as well as discovery of drug-like compounds for their gene expression profiles in different organs of treated mice in an acute experiment. For each compound, 896 QRT-PCR were done: four organs were used from each of the treated four animals to monitor the relative expression of 56 genes. Based on expression data of the discovery gene set of toxicology biomarkers the cardio- and nephrotoxicity of doxorubicin and sulfasalazin, the hepato- and nephrotoxicity of rotenone, dihydrocoumarin and aniline, and the liver toxicity of 2,4-diaminotoluene could be confirmed. The acute heart and kidney toxicity of the active metabolite SN-38 from its less toxic prodrug, irinotecan could be differentiated, and two novel gene markers for hormone replacement therapy were identified, namely fabp4 and pparg, which were down-regulated by estradiol treatment. PMID:22016648

Acute and Cumulative Effects of Unmodified 50-nm Nano-ZnO on Mice.

PubMed

Kong, Tao; Zhang, Shu-Hui; Zhang, Ji-Liang; Hao, Xue-Qin; Yang, Fan; Zhang, Cai; Yang, Zi-Jun; Zhang, Meng-Yu; Wang, Jie

2018-01-02

Nanometer zinc oxide (nano-ZnO) is widely used in diverse industrial and agricultural fields. Due to the extensive contact humans have with these particles, it is crucial to understand the potential effects that nano-ZnO have on human health. Currently, information related to the toxicity and mechanisms of nano-ZnO is limited. The aim of the present study was to investigate acute and cumulative toxic effects of 50-nm unmodified ZnO in mice. This investigation will seek to establish median lethal dose (LD50), a cumulative coefficient, and target organs. The acute and cumulative toxicity was investigated by Karber's method and via a dose-increasing method, respectively. During the experiment, clinical signs, mortality, body weights, hematology, serum biochemistry, gross pathology, organ weight, and histopathology were examined. The LD50 was 5177-mg/kg·bw; the 95% confidence limits for the LD50 were 5116-5238-mg/kg·bw. It could be concluded that the liver, kidney, lung, and gastrointestinal tract were target organs for the 50-nm nano-ZnO acute oral treatment. The cumulative coefficient (K) was 1.9 which indicated that the cumulative toxicity was apparent. The results also indicated that the liver, kidney, lung, and pancrea were target organs for 50-nm nano-ZnO cumulative oral exposure and might be target organs for subchronic and chronic toxicity of oral administered 50-nm ZnO.

Organic chloramines in drinking water: An assessment of formation, stability, reactivity and risk.

PubMed

How, Zuo Tong; Linge, Kathryn L; Busetti, Francesco; Joll, Cynthia A

2016-04-15

Although organic chloramines are known to form during the disinfection of drinking water with chlorine, little information is currently available on their occurrence or toxicity. In a recent in vitro study, some organic chloramines (e.g. N-chloroglycine) were found to be cytotoxic and genotoxic even at micromolar concentrations. In this paper, the formation and stability of 21 different organic chloramines, from chlorination of simple amines and amino acids, were studied, and the competition between 20 amino acids during chlorination was also investigated. For comparison, chlorination of two amides was also conducted. The formation and degradation of selected organic chloramines were measured using either direct UV spectroscopic or colorimetric detection. Although cysteine, methionine and tryptophan were the most reactive amino acids towards chlorination, they did not form organic chloramines at the chlorine to precursor molar ratios that were tested. Only 6 out of the 21 organic chloramines formed had a half-life of more than 3 h, although this group included all organic chloramines formed from amines. A health risk assessment relating stability and reactivity data from this study to toxicity and precursor abundance data from the literature indicated that only N-chloroglycine is likely to be of concern due to its stability, toxicity and abundance in water. However, given the stability of organic chloramines formed from amines, more information about the toxicity and precursor abundance for these chloramines is desirable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of Malaysian peatlands decreases levels of phenolics in soil and in leaves of Macaranga pruinosa

NASA Astrophysics Data System (ADS)

Yule, Catherine; Lim, Yau; Lim, Tse

2016-04-01

Indo-Malaysian tropical peat swamp forests (PSF) sequester enormous stores of carbon in the form of phenolic compounds, particularly lignin as well as tannins. These phenolic compounds are crucial for ecosystem functioning in PSF through their inter-related roles in peat formation and plant defenses. Disturbance of PSF causes destruction of the peat substrate, but the specific impact of disturbance on phenolic compounds in peat and its associated vegetation has not previously been examined. A scale was developed to score peatland degradation based on the three major human impacts that affect tropical PSF - logging, drainage and fire. The objectives of this study were to compare the amount of phenolic compounds in Macaranga pruinosa, a common PSF tree, and in the peat substrate along a gradient of peatland degradation from pristine peat swamp forest to cleared, drained and burnt peatlands. We examined phenolic compounds in M. pruinosa and in peat and found that levels of total phenolic compounds and total tannins decrease in the leaves of M.pruinosa and also in the surface peat layers with an increase in peatland degradation. We conclude that waterlogged conditions preserve the concentration of phenolic compounds in peat, and that even PSF that has been previously logged but which has recovered a full canopy cover will have high levels of total phenolic content (TPC) in peat. High levels of TPC in peat and in the flora are vital for the inhibition of decomposition of organic matter and this is crucial for the accretion of peat and the sequestration of carbon. Thus regional PSF flourish despite the phenolic rich, toxic, waterlogged, nutrient poor, conditions, and reversal of such conditions is a sign of degradation.

[Myotonic dystrophies: clinical presentation, pathogenesis, diagnostics and therapy].

PubMed

Finsterer, Josef; Rudnik-Schöneborn, S

2015-01-01

The autosomal-dominant myotonic dystrophies dystrophia myotonica type-1 (DM1, Curschmann-Steinert disease) and dystrophia myotonica type-2 (DM2, proximal myotonic myopathy (PROMM)), are, contrary to the non-dystrophic myotonias, progressive multisystem disorders. DM1 and DM2 are the most frequent of the muscular dystrophies. In both diseases the skeletal muscle is the most severely affected organ (weakness, wasting, myotonia, myalgia). Additionally, they manifest in the eye, heart, brain, endocrine glands, gastrointestinal tract, skin, skeleton, and peripheral nerves. Phenotypes of DM1 may be classified as congenital, juvenile, classical, or late onset. DM2 is a disorder of the middle or older age and usually has a milder course compared to DM1. DM1 is due to a CTG-repeat expansion > 50 repeats in the non-coding 3' UTR of the DMPK-gene. DM2 is caused by a CCTG-repeat expansion to 75 - 11 000 repeats in intron-1 of the CNBP/ZNF9 gene. Mutant pre-mRNAs of both genes aggregate within the nucleus (nuclear foci), which sequester RNA-binding proteins and result in an abnormal protein expression via alternative splicing in downstream effector genes (toxic RNA diseases). Other mechanisms seem to play an additional pathogenetic role. Clinical severity of DM1 increases from generation to generation (anticipation). The higher the repeat expansion the more severe the DM1 phenotype. In DM2 severity of symptoms and age at onset do not correlate with the expansion size. Contrary to DM2, there is a congenital form and anticipation in DM1. © Georg Thieme Verlag KG Stuttgart · New York.

How useful are the "other" semipermeable membrane devices (SPMDs); the mini-unit (15.2 cm long)?

USGS Publications Warehouse

Goodbred, Steven L.; Bryant, Wade L.; Rosen, Michael R.; Alvarez, David; Spencer, Terri

2009-01-01

Mini (15.2 cm) semipermeable membrane devices (SPMDs) were used successfully in 169 streams from six metropolitan areas of the US to sequester hydrophobic organic compounds (HOCs) that are indicative of urbanization. A microscale assay the P450RGS, which responds to compounds that bind to the aryl hydrocarbon receptor (AhR), and the Fluoroscan, a chemical screen for polycyclic aromatic hydrocarbons (PAHs), were performed on each mini SPMD extract. Results show both tests were sensitive enough to respond in streams with low urbanization and responded exponentially in a predictable way to a gradient of urbanization. Mini SPMDs had sufficient sampling rates to detect HOCs using gas chromatography with mass spectrometric detection (GC/MS) in streams with low levels of urbanization. The total number of HOCs in streams had a linear response to a gradient of urbanization, where 73 of 140 targeted compounds were detected. A diverse group of compounds was found in urban streams including, PAHs, insecticides, herbicides, musk fragrances, waste water treatment compounds and flame retardants. Pentachloroanisole (PCA), a breakdown product of pentachlorophenol (wood preservative), was the most ubiquitous HOC, and was detected in 71% of streams. An evaluation of mini SPMD performance showed they can detect concentrations in water below toxicity benchmarks for many HOCs with the exception of 2,3,7,8 tetrachlorodibenzo-p-dioxin. A comparison of mini SPMDs with full sized (91.4 cm) SPMDs showed they have several distinct advantages. The most notable advantages are their low cost, small size, and reduced chance of vandalism. The greatest limitation is the inability to detect compounds at low concentrations (pg/L). Mini SPMDs perform quite well in a wide array of environmental settings and applications and should be considered as an option in environmental studies.

Imaging heterostructured quantum dots in cultured cells with epifluorescence and transmission electron microscopy

PubMed Central

Rivera, Erin M.; Provencio, Casilda Trujillo; Steinbruck, Andrea; Rastogi, Pawan; Dennis, Allison; Hollingsworth, Jennifer; Serrano, Elba

2011-01-01

Quantum dots (QDs) are semiconductor nanocrystals with extensive imaging and diagnostic capabilities, including the potential for single molecule tracking. Commercially available QDs offer distinct advantages over organic fluorophores, such as increased photostability and tunable emission spectra, but their cadmium selenide (CdSe) core raises toxicity concerns. For this reason, replacements for CdSe-based QDs have been sought that can offer equivalent optical properties. The spectral range, brightness and stability of InP QDs may comprise such a solution. To this end, LANL/CINT personnel fabricated moderately thick-shell novel InP QDs that retain brightness and emission over time in an aqueous environment. We are interested in evaluating how the composition and surface properties of these novel QDs affect their entry and sequestration within the cell. Here we use epifluorescence and transmission electron microscopy (TEM) to evaluate the structural properties of cultured Xenopus kidney cells (A6; ATCC) that were exposed either to commercially available CdSe QDs (Qtracker® 565, Invitrogen) or to heterostructured InP QDs (LANL). Epifluorescence imaging permitted assessment of the general morphology of cells labeled with fluorescent molecular probes (Alexa Fluor® ® phalloidin; Hoechst 33342), and the prevalence of QD association with cells. In contrast, TEM offered unique advantages for viewing electron dense QDs at higher resolution with regard to subcellular sequestration and compartmentalization. Preliminary results show that in the absence of targeting moieties, InP QDs (200 nM) can passively enter cells and sequester nonspecifically in cytosolic regions whereas commercially available targeted QDs principally associate with membranous structures within the cell. Supported by: NIH 5R01GM084702. PMID:21808662

Toxicity of Engineered Nanoparticles in the Environment

PubMed Central

Maurer-Jones, Melissa A.; Gunsolus, Ian L.; Murphy, Catherine J.; Haynes, Christy L.

2014-01-01

While nanoparticles occur naturally in the environment and have been intentionally used for centuries, the production and use of engineered nanoparticles has seen a recent spike, which makes environmental release almost certain. Therefore, recent efforts to characterize the toxicity of engineered nanoparticles have focused on the environmental implications, including exploration of toxicity to organisms from wide-ranging parts of the ecosystem food webs. Herein, we summarize the current understanding of toxicity of engineered nanoparticles to representatives of various trophic levels, including bacteria, plants, and multicellular aquatic/terrestrial organisms, to highlight important challenges within the field of econanotoxicity, challenges that analytical chemists are expertly poised to address. PMID:23427995

Toxicity of engineered nanoparticles in the environment.

PubMed

Maurer-Jones, Melissa A; Gunsolus, Ian L; Murphy, Catherine J; Haynes, Christy L

2013-03-19

While nanoparticles occur naturally in the environment and have been intentionally used for centuries, the production and use of engineered nanoparticles has seen a recent spike, which makes environmental release almost certain. Therefore, recent efforts to characterize the toxicity of engineered nanoparticles have focused on the environmental implications, including exploration of toxicity to organisms from wide-ranging parts of the ecosystem food webs. Herein, we summarize the current understanding of toxicity of engineered nanoparticles to representatives of various trophic levels, including bacteria, plants, and multicellular aquatic/terrestrial organisms, to highlight important challenges within the field of econanotoxicity, challenges that analytical chemists are expertly poised to address.

Relationship between Composition and Toxicity of Motor Vehicle Emission Samples

PubMed Central

McDonald, Jacob D.; Eide, Ingvar; Seagrave, JeanClare; Zielinska, Barbara; Whitney, Kevin; Lawson, Douglas R.; Mauderly, Joe L.

2004-01-01

In this study we investigated the statistical relationship between particle and semivolatile organic chemical constituents in gasoline and diesel vehicle exhaust samples, and toxicity as measured by inflammation and tissue damage in rat lungs and mutagenicity in bacteria. Exhaust samples were collected from “normal” and “high-emitting” gasoline and diesel light-duty vehicles. We employed a combination of principal component analysis (PCA) and partial least-squares regression (PLS; also known as projection to latent structures) to evaluate the relationships between chemical composition of vehicle exhaust and toxicity. The PLS analysis revealed the chemical constituents covarying most strongly with toxicity and produced models predicting the relative toxicity of the samples with good accuracy. The specific nitro-polycyclic aromatic hydrocarbons important for mutagenicity were the same chemicals that have been implicated by decades of bioassay-directed fractionation. These chemicals were not related to lung toxicity, which was associated with organic carbon and select organic compounds that are present in lubricating oil. The results demonstrate the utility of the PCA/PLS approach for evaluating composition–response relationships in complex mixture exposures and also provide a starting point for confirming causality and determining the mechanisms of the lung effects. PMID:15531438

Pesticide toxicity index for freshwater aquatic organisms, 2nd edition

USGS Publications Warehouse

Munn, Mark D.; Gilliom, Robert J.; Moran, Patrick W.; Nowell, Lisa H.

2006-01-01

The U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program is designed to assess current water-quality conditions, changes in water quality over time, and the effects of natural and human factors on water quality for the Nation's streams and ground-water resources. For streams, one of the most difficult parts of the assessment is to link chemical conditions to effects on aquatic biota, particularly for pesticides, which tend to occur in streams as complex mixtures with strong seasonal patterns. A Pesticide Toxicity Index (PTI) was developed that combines pesticide exposure of aquatic biota (measured concentrations of pesticides in stream water) with acute toxicity estimates (standard endpoints from laboratory bioassays) to produce a single index value for a sample or site. The development of the PTI was limited to pesticide compounds routinely measured in NAWQA studies and to toxicity data readily available from existing databases. Qualifying toxicity data were found for one or more types of test organisms for 124 of the 185 pesticide compounds measured in NAWQA samples, but with a wide range of available bioassays per compound (1 to 232). In the databases examined, there were a total of 3,669 bioassays for the 124 compounds, including 398 48-hour EC50 values (concentration at which 50 percent of test organisms exhibit a sublethal response) for freshwater cladocerans, 699 96-hour LC50 values (concentration lethal to 50 percent of test organisms) for freshwater benthic invertebrates, and 2,572 96-hour LC50 values for freshwater fish. The PTI for a particular sample is the sum of toxicity quotients (measured concentration divided by the median toxicity concentration from bioassays) for each detected pesticide, and thus, is based on the concentration addition model of pesticide toxicity. The PTI can be calculated for specific groups of pesticides and for specific taxonomic groups. Although the PTI does not determine whether water in a sample is toxic to aquatic organisms, its values can be used to rank or compare the toxicity of samples or sites on a relative basis for use in further analysis or additional assessments. The PTI approach may be useful as a basis for comparing the potential significance of pesticides in different streams on a common basis, for evaluating relations between pesticide exposure and observed biological conditions, and for prioritizing where further studies are most needed.

In-situ subaqueous capping of mercury-contaminated sediments in a fresh-water aquatic system, Part II-evaluation of sorption materials.

PubMed

Randall, Paul M; Yates, Brian J; Lal, Vivek; Darlington, Ramona; Fimmen, Ryan

2013-08-01

The function and longevity of traditional, passive, isolation caps can be augmented through the use of more chemically active capping materials which have higher sorptive capacities, ideally rendering metals non-bioavailable. In the case of Hg, active caps also mitigate the rate and extent of methylation. This research examined low cost, readily available, capping materials for their ability to sequester Hg and MeHg. Furthermore, selected capping materials were evaluated to inhibit the methylation of Hg in an incubation study as well as the capacity of a selected capping material to inhibit translocation of Hg and MeHg with respect to ebullition-facilitated contaminant transport in a column study. Results indicated that bauxite had a better capacity for mercury sorption than the other test materials. However, bauxite as well as soil capping materials did not decrease methylation to a significant extent. Materials with larger surface areas, higher organic matter and acid volatile sulfide (AVS) content displayed a larger partitioning coefficient. In the incubation experiments, the presence of a carbon source (lactate), electron acceptor (sulfate) and the appropriate strains of SRB provided the necessary conditions for Hg methylation to occur. The column study showed effectiveness in sequestering Hg and MeHg and retarding transport to the overlying water column; however, disturbances to the soil capping material resulting from gas ebullition negated its effectiveness. Published by Elsevier Inc.

Autophagosome and phagosome.

PubMed

Deretic, Vojo

2008-01-01

Autophagy and phagocytosis are evolutionarily ancient processes functioning in capture and digestion of material found in the cellular interior and exterior, respectively. In their most primordial form, both processes are involved in cellular metabolism and feeding, supplying cells with externally obtained particulate nutrients or using portions of cell's own cytoplasm to generate essential nutrients and energy at times of starvation. Although autophagy and phagocytosis are commonly treated as completely separate biological phenomena, they are topologically similar and can be, at least morphologically, viewed as different manifestations of a spectrum of related processes. Autophagy is the process of sequestering portions of cellular interior (cytosol and intracellular organelles) into a membranous organelle (autophagosome), whereas phagocystosis is its topological equivalent engaged in sequestering cellular exterior. Both autophagosomes and phagosomes mature into acidified, degradative organelles, termed autolysosomes and phagolysosomes, respectively. The basic role of autophagy as a nutritional process, and that of phagocytosis where applicable, has survived in present-day organisms ranging from yeast to man. It has in addition evolved into a variety of specialized processes in metazoans, with a major role in cellular/cytoplasmic homeostasis. In humans, autophagy has been implicated in many health and disease states, including cancer, neurodegeneration, aging and immunity, while phagocytosis plays a role in immunity and tissue homeostasis. Autophagy and phagocytosis cooperate in the latter two processes. In this chapter, we briefly review the regulatory and execution stages of both autophagy and phagocytosis.

Crystal Structure of the Zorbamycin-Binding Protein ZbmA, the Primary Self-Resistance Element in Streptomyces flavoviridis ATCC21892

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudolf, Jeffrey D.; Bigelow, Lance; Chang, Changsoo

The bleomycins (BLMs), tallysomycins (TLMs), phleomycin, and zorbamycin (ZBM) are members of the BLM family of glycopeptide-derived antitumor antibiotics. The BLM-producing Streptomyces verticillus ATCC15003 and the TLM-producing Streptoalloteichus hindustanus E465-94 ATCC31158 both possess at least two self-resistance elements, an N-acetyltransferase and a binding protein. The N-acetyltransferase provides resistance by disrupting the metal-binding domain of the antibiotic that is required for activity, while the binding protein confers resistance by sequestering the metal-bound antibiotic and preventing drug activation via molecular oxygen. We recently established that the ZBM producer, Streptomyces flavoviridis ATCC21892, lacks the N-acetyltransferase resistance gene and that the ZBM-binding protein, ZbmA,more » is sufficient to confer resistance in the producing strain. To investigate the resistance mechanism attributed to ZbmA, we determined the crystal structures of apo and Cu(II)-ZBM-bound ZbmA at high resolutions of 1.90 and 1.65 angstrom, respectively. A comparison and contrast with other structurally characterized members of the BLM-binding protein family revealed key differences in the protein ligand binding environment that fine-tunes the ability of ZbmA to sequester metal-bound ZBM and supports drug sequestration as the primary resistance mechanism in the producing organisms of the BLM family of antitumor antibiotics.« less

A 1-D Simulation Analysis of the Development and Maintenance of the 2001 Red Tide of the Ichthyotoxic Dinoflagellate Karenia brevis on the West Florida Shelf

DTIC Science & Technology

2012-04-26

subsequent fish kills supplied additional organic nutrients for utilization by these opportunistic toxic algae. Both nutrient vectors represented organic non...ichthyotoxic levels, rapid decay of subsequent fish kills supplied additional organic nutrients for utilization by these opportunistic toxic algae. Both...HABSIM model (Fig. 2) a positive feedback of the recycled organic nutrients (DON and DOP) from decaying fish , killed by K. brevis. Note that dissolved

Sequestering the Gravitino: Neutralino Dark Matter in Gauge Mediation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Craig, Nathaniel J.; /Stanford U., Dept. Phys.; Green, Daniel

2008-08-15

In conventional models of gauge-mediated supersymmetry breaking, the lightest supersymmetric particle (LSP) is invariably the gravitino. However, if the supersymmetry breaking sector is strongly coupled, conformal sequestering may raise the mass of the gravitino relative to the remaining soft supersymmetry-breaking masses. In this letter, we demonstrate that such conformal dynamics in gauge-mediated theories may give rise to satisfactory neutralino dark matter while simultaneously solving the flavor and {mu}/B{mu} problems.

Genome Sequence of Carbon Dioxide-Sequestering Serratia sp. Strain ISTD04 Isolated from Marble Mining Rocks.

PubMed

Kumar, Manish; Gazara, Rajesh Kumar; Verma, Sandhya; Kumar, Madan; Verma, Praveen Kumar; Thakur, Indu Shekhar

2016-10-20

The Serratia sp. strain ISTD04 has been identified as a carbon dioxide (CO 2 )-sequestering bacterium isolated from marble mining rocks in the Umra area, Rajasthan, India. This strain grows chemolithotrophically on media that contain sodium bicarbonate (NaHCO 3 ) as the sole carbon source. Here, we report the genome sequence of 5.07 Mb Serratia sp. ISTD04. Copyright © 2016 Kumar et al.

Budget Issues: Effects of the Fiscal Year 1990 Sequester on the Department of Education. Fact Sheet for the Chairman, Committee on the Budget, House of Representatives.

ERIC Educational Resources Information Center

General Accounting Office, Washington, DC.

The Balanced Budget and Emergency Deficit Control Act of 1985, as amended, establishes deficit targets to lead to a balanced unified budget by fiscal year 1993. If the Office of Management and Budget projects a deficit in excess of the target amount plus $10 billion, the President must issue a sequester order to reduce budget resources…

Biogeochemical Processes Related to Metal Removal and Toxicity Reduction in the H-02 Constructed Wetland, Savannah River Site

NASA Astrophysics Data System (ADS)

Burgess, E. A.; Mills, G. L.; Harmon, M.; Samarkin, V.

2011-12-01

The H-02 wetland system was designed to treat building process water and storm water runoff from multiple sources associated with the Tritium Facility at the DOE-Savannah River Site, Aiken, SC. The wetland construction included the addition of gypsum (calcium sulfate) to foster a sulfate-reducing bacterial population. Conceptually, the wetland functions as follows: ? Cu and Zn initially bind to both dissolved and particulate organic detritus within the wetland. ? A portion of this organic matter is subsequently deposited into the surface sediments within the wetland. ? The fraction of Cu and Zn that is discharged in the wetland effluent is organically complexed, less bioavailable, and consequently, less toxic. ? The Cu and Zn deposited in the surface sediments are eventually sequestered into insoluble sulfide minerals in the wetland. Development of the H-02 system has been closely monitored; sampling began in August 2007, shortly after its construction. This monitoring has included the measurement of water quality parameters, Cu and Zn concentrations in surface water and sediments, as well as, characterization of the prokaryotic (e.g., bacterial) component of wetland biogeochemical processes. Since the beginning of the study, the mean influent Cu concentration was 31.5±12.1 ppb and the mean effluent concentration was 11.9±7.3 ppb, corresponding to an average Cu removal of 64%. Zn concentrations were more variable, averaging 39.2±13.8 ppb in the influent and 25.7±21.3 ppb in the effluent. Average Zn removal was 52%. The wetland also ameliorated high pH values associated with influent water to values similar to those measured at reference sites. Seasonal variations in DOC concentration corresponded to seasonal variations in Cu and Zn removal efficiency. The concentration of Cu and Zn in the surface layer of the sediments has increased over the lifetime of the wetland and, like removal efficiency, demonstrated seasonal variation. Within its first year, the H-02 wetland showed biomarkers for sulfate-reducing bacteria. Sulfate-reduction and methane-oxidation rates in the sediments were determined using radiotracer techniques. Sulfate-reduction was detected in all depths of sediment cores, even in surface detritus layers. Gas measurements from H-02 sediments demonstrated that methane is available to support a methane oxidizing community, and active methane-oxidation was detected in the sediments and overlying water. Our results demonstrate that the H-02 wetlands are functioning successfully to remove Cu and Zn from influent waters. The continued success and long-term sustainability of the functioning H-02 system is predicated on maintaining in situ biogeochemistry. However, the relative importance of various biogeochemical cycles remains unclear. For example, the Cu and Zn deposited in the sediments are associated with organic detritus at the sediment surface; the extent and rate at which the metals will redistribute to more recalcitrant sulfide mineral phases remain to be determined. Thus, the H-02 wetland system is a valuable resource not only for metal removal at SRS, but also can further enhance the understanding of wetland function within the scientific and regulatory communities.

An étude on global vacuum energy sequester

DOE PAGES

D’Amico, Guido; Kaloper, Nemanja; Padilla, Antonio; ...

2017-09-18

Recently two of the authors proposed a mechanism of vacuum energy sequester as a means of protecting the observable cosmological constant from quantum radiative corrections. The original proposal was based on using global Lagrange multipliers, but later a local formulation was provided. Subsequently other interesting claims of a different non-local approach to the cosmological constant problem were made, based again on global Lagrange multipliers. We examine some of these proposals and find their mutual relationship. We explain that the proposals which do not treat the cosmological constant counterterm as a dynamical variable require fine tunings to have acceptable solutions. Furthermore,more » the counterterm often needs to be retuned at every order in the loop expansion to cancel the radiative corrections to the cosmological constant, just like in standard GR. These observations are an important reminder of just how the proposal of vacuum energy sequester avoids such problems.« less

Metal-organic frameworks for the removal of toxic industrial chemicals and chemical warfare agents.

PubMed

Bobbitt, N Scott; Mendonca, Matthew L; Howarth, Ashlee J; Islamoglu, Timur; Hupp, Joseph T; Farha, Omar K; Snurr, Randall Q

2017-06-06

Owing to the vast diversity of linkers, nodes, and topologies, metal-organic frameworks can be tailored for specific tasks, such as chemical separations or catalysis. Accordingly, these materials have attracted significant interest for capture and/or detoxification of toxic industrial chemicals and chemical warfare agents. In this paper, we review recent experimental and computational work pertaining to the capture of several industrially-relevant toxic chemicals, including NH 3 , SO 2 , NO 2 , H 2 S, and some volatile organic compounds, with particular emphasis on the challenging issue of designing materials that selectively adsorb these chemicals in the presence of water. We also examine recent research on the capture and catalytic degradation of chemical warfare agents such as sarin and sulfur mustard using metal-organic frameworks.

THE EFFECT OF KILLED BACTERIA ON THE SERUM FERMENTS AND ANTIFERMENT : STUDIES ON FERMENT ACTION. XXVII.

PubMed

Jobling, J W; Petersen, W; Eggstein, A A

1915-11-01

1. The intravenous injection of killed organisms is followed by the mobilization of a non-specific protease and lipase; the rapidity and extent of this reaction depend upon the toxicity of the organism and on the resistance of the organism to proteolysis. 2. The temperature and leucocytic curve bear no relation to the ferment changes. 3. The serum antiferment is usually increased after the injection. 4. Of the organisms studied, the typhoid bacilli produced the most marked ferment changes, and the tubercle bacilli the least. 5. The toxicity of the dried organisms cannot depend wholly upon proteolysis in vivo, but must depend in part on the preformed toxic substances liberated on lysis. 6. Serum protease should not be considered as the sole exciter of intoxication through the production of protein split products; it seems possible that its function may in part be one of detoxication.

TOXIC EQUIVALENCY FACTORS (TEFS) FOR PCBS, PCDDS, PCDFS FOR HUMANS AND WILDLIFE

EPA Science Inventory

An expert meeting was organized by the World Health Organization (WHO) and held ih Stockholm on 15-18 June 1997. The objective of this meeting was to derive cohsensus toxic equivalency factors (TEFs) for polychlorinated didbenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dio...

FROM INDIVIDUALS TO POPULATIONS: MODELING TOXICITY DATA ACROSS LEVELS OF BIOLOGICAL ORGANIZATION

EPA Science Inventory

Raimondo, Sandy and Charles L. McKenney, Jr. In press. From Individuals to Populations: Modeling Toxicity Data Across Levels of Biological Organization (Abstract). To be presented at the SETAC Fourth World Congress, 14-18 November 2004, Portland, OR. 1 p. (ERL,GB R1012).

...

INTERSPECIES CORRELATION ESTIMATION (ICE) FOR ACUTE TOXICITY TO AQUATIC ORGANISMS AND WILDLIFE. II. USER MANUAL AND SOFTWARE

EPA Science Inventory

Asfaw, Amha, Mark R. Ellersieck and Foster L. Mayer. 2003. Interspecies Correlation Estimations (ICE) for Acute Toxicity to Aquatic Organisms and Wildlife. II. User Manual and Software. EPA/600/R-03/106. U.S. Environmental Protection Agency, National Health and Environmental Effe...

Frameworks for organizing exposure and toxicity data - the Aggregate Exposure Pathway (AEP) and the Adverse Outcome Pathway (AOP)

EPA Science Inventory

The Adverse Outcome Pathway (AOP) framework organizes existing knowledge regarding a series of biological events, starting with a molecular initiating event (MIE) and ending at an adverse outcome. The AOP framework provides a biological context to interpret in vitro toxicity dat...

40 CFR 464.21 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 464.21 Specialized definitions. For the purpose of this subpart: (a) Total Toxic Organics (TTO). TTO... comprised of a discrete list of toxic organic pollutants for each process segment where it is regulated, as.... chrysene 77. acenaphthylene 78. anthracene 81. phenanthrene 84. pyrene (5) Mold Cooling (§ 464.25(g) and...

40 CFR 464.31 - Specialized definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... § 464.31 Specialized definitions. For the purpose of this subpart: (a) Total Toxic Organics (TTO). TTO... comprised of a discrete list of toxic organic pollutants for each process segment where it is regulated, as...-benzanthracene) 76. chrysene 77. acenaphthylene 78. anthracene 80. fluorene 81. phenanthrene 84. pyrene (5) Mold...

Toxic remediation

DOEpatents

Matthews, Stephen M.; Schonberg, Russell G.; Fadness, David R.

1994-01-01

What is disclosed is a novel toxic waste remediation system designed to provide on-site destruction of a wide variety of hazardous organic volatile hydrocarbons, including but not limited to halogenated and aromatic hydrocarbons in the vapor phase. This invention utilizes a detoxification plenum and radiation treatment which transforms hazardous organic compounds into non-hazardous substances.