Sublethal Effects of Insecticide Exposure on Megacopta cribraria (Fabricius) Nymphs: Key Biological Traits and Acetylcholinesterase Activity.

PubMed

Miao, Jin; Reisig, Dominic D; Li, Guoping; Wu, Yuqing

2016-01-01

Megacopta cribraria F. (Hemiptera: Plataspidae), the kudzu bug, is an invasive insect pest of U.S. soybean. At present, insecticide application is the primary and most effective control option for M. cribraria In this study, the potential effects of sublethal and low-lethal concentrations (LC10 and LC40) of three common insecticides on key biological traits and acetylcholinesterase (AChE) activity of the treated nymphal stage of insect were assessed. The results show that the sublethal concentration of imidacloprid significantly reduced adult emergence rate of M. cribraria A low-lethal concentration of imidacloprid significantly increased nymphal development time, but significantly decreased adult emergence rate and adult longevity. Both sublethal and low-lethal concentrations of acephate caused an increase in nymphal development time and a reduction in adult emergence rate and adult longevity. Fecundity of females was significantly reduced only by exposure to low-lethal concentrations of acephate. Sublethal and low-lethal concentrations of bifenthrin increased nymphal development time, but significantly decreased adult emergence rate. In addition, we found that the AChE activity of M. cribraria was significantly increased only by LC40 imidacloprid, but strongly inhibited by acephate. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Artemisia herba-alba essential oil from Buseirah (South Jordan): Chemical characterization and assessment of safe antifungal and anti-inflammatory doses.

PubMed

Abu-Darwish, M S; Cabral, C; Gonçalves, M J; Cavaleiro, C; Cruz, M T; Efferth, T; Salgueiro, L

2015-11-04

Artemisia herba-alba Asso ("desert wormwood" in English; "armoise blanche" in French; "shaih" in Arabic), is a medicinal and strongly aromatic plant widely used in traditional medicine by many cultures since ancient times. It is used to treat inflammatory disorders (colds, coughing, bronchitis, diarrhea), infectious diseases (skin diseases, scabies, syphilis) and others (diabetes, neuralgias). In Jordanian traditional medicine, this plant is used as antiseptic and against skin diseases, scabies, syphilis, fever as well as menstrual and nervous disorders. Considering the traditional medicinal uses and the lack of scientific studies addressing the cellular and molecular players involved in these biological activities, the present study was designed to unveil the antifungal and anti-inflammatory activities of A. herba-alba Asso essential oil at doses devoid of toxicity to mammalian cells. Chemical analysis of A. herba-alba essential oil isolated by hydrodistillation from aerial parts was carried out by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antifungal activity (minimal inhibitory concentrations and minimal lethal concentrations) was evaluated against yeasts, dermatophyte and Aspergillus strains. In order to explore the mechanisms behind the anti-fungal effect of the essential oil, the germ tube inhibition assay was evaluated using Candida albicans. The assessment of cell viability was accomplished using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the in vitro anti-inflammatory potential of A. herba-alba oil at the periphery and central nervous system was evaluated by measuring nitric oxide (NO) production using lipopolysaccharide (LPS)-stimulated mouse macrophages and microglia, respectively. Oxygen-containing monoterpenes are the main compounds of the oil, namely 1,8-cineole (20.1%), β-thujone (25.1%), α-thujone (22.9%) and camphor (10.5%). Among the fungal strains tested, the oil demonstrated potential against Trichophyton rubrum and Epidermophyton floccosum, with minimal inhibitory concentration (MIC) and minimal lethal concentration (MCL) values of 0.32 mg/mL and Cryptococcus neoformans with MIC of 0.64 mg/mL. The oil revealed a strong inhibitory effect on germ tube formation in C. albicans with inhibition of filamentation around 90% at a concentration 0.16 mg/mL. Importantly, the essential oil significantly inhibited NO production evoked by LPS without cytotoxicity at concentrations up to 1.25 µL/mL in macrophages and up to 0.32 µL/mL in microglia. Furthermore, evaluation of cell viability in RAW 264.7 macrophages, BW2 microgliacells and HaCaT keratinocytes showed no cytotoxicity at concentrations up to 0.32 μL/mL. It was possible to find appropriate doses of A. herba-alba oil with both antifungal and anti-inflammatory activities and without detrimental effects towards several mammalian cell types. These findings add significant information to the pharmacological activity of A. herba-alba essential oil, specifically to its antifungal and anti-inflammatory therapeutic value, thus justifying and reinforcing the use of this plant in traditional medicine. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Effects of 5-Fluorodeoxyuridine and Related Halogenated Pyrimidines on the Sand-Dollar Embryo

PubMed Central

Karnofsky, David A.; Basch, Ross S.

1960-01-01

The embryo of the sand-dollar (Echinarachnius parma) was exposed to various concentrations of fluorinated pyrimidines immediately after fertilization. FUDR (5-fluorodeoxyuridine) was most active, and a concentration of 2 to 4 mγ/10 cc. (0.8 to 1.6 x 10-6 m.eq./liter) blocked development at the early blastula stage. Larger doses interrupted development at the same stage. This effect was prevented by thymidine (TDR) and thymine (T); and these pyrimidines protected against many times the minimal lethal concentration of FUDR. TDR was active as a protective agent if added just before early blastula formation. The other fluorinated pyrimidines, 5-fluorouracil (FU), 5-fluorouridine (FUR), 5-fluorocytidine (FCR), 5-fluorodeoxycytidine (FCDR), and 5-fluoroorotic acid (FO), were also studied. These drugs produced effects on embryonic development similar to those seen with FUDR. The effective concentrations, however, varied greatly. T and TDR provided protection against these drugs, but in most cases they were not so effective as against FUDR. 5-Bromodeoxyurdine (BrUDR), beginning at the early blastula stage, caused a random pattern of embryonic death up to the pluteus stage. This drug has been shown to be incorporated into bacterial DNA. BrUDR protected embryos against the early lethal effects of FUDR presumably acting as a thymidine substitute, but the embryos died subsequently in a pattern similar to that seen with BrUDR alone. FUDR and BrUDR appear to inhibit the formation and alter the structure of DNA, respectively, distinctive effects whch may provide a means for studying the role of DNA in embryonic development. PMID:14404541

Effects of 5-fluorodeoxyuridine and related halogenated pyrimidines on the sand-dollar embryo.

PubMed

KARNOFSKY, D A; BASCH, R S

1960-02-01

The embryo of the sand-dollar (Echinarachnius parma) was exposed to various concentrations of fluorinated pyrimidines immediately after fertilization. FUDR (5-fluorodeoxyuridine) was most active, and a concentration of 2 to 4 mgamma/10 cc. (0.8 to 1.6 x 10(-6) m.eq./liter) blocked development at the early blastula stage. Larger doses interrupted development at the same stage. This effect was prevented by thymidine (TDR) and thymine (T); and these pyrimidines protected against many times the minimal lethal concentration of FUDR. TDR was active as a protective agent if added just before early blastula formation. The other fluorinated pyrimidines, 5-fluorouracil (FU), 5-fluorouridine (FUR), 5-fluorocytidine (FCR), 5-fluorodeoxycytidine (FCDR), and 5-fluoroorotic acid (FO), were also studied. These drugs produced effects on embryonic development similar to those seen with FUDR. The effective concentrations, however, varied greatly. T and TDR provided protection against these drugs, but in most cases they were not so effective as against FUDR. 5-Bromodeoxyurdine (BrUDR), beginning at the early blastula stage, caused a random pattern of embryonic death up to the pluteus stage. This drug has been shown to be incorporated into bacterial DNA. BrUDR protected embryos against the early lethal effects of FUDR presumably acting as a thymidine substitute, but the embryos died subsequently in a pattern similar to that seen with BrUDR alone. FUDR and BrUDR appear to inhibit the formation and alter the structure of DNA, respectively, distinctive effects whch may provide a means for studying the role of DNA in embryonic development.

Elimination of water pathogens with solar radiation using an automated sequential batch CPC reactor.

PubMed

Polo-López, M I; Fernández-Ibáñez, P; Ubomba-Jaswa, E; Navntoft, C; García-Fernández, I; Dunlop, P S M; Schmid, M; Byrne, J A; McGuigan, K G

2011-11-30

Solar disinfection (SODIS) of water is a well-known, effective treatment process which is practiced at household level in many developing countries. However, this process is limited by the small volume treated and there is no indication of treatment efficacy for the user. Low cost glass tube reactors, together with compound parabolic collector (CPC) technology, have been shown to significantly increase the efficiency of solar disinfection. However, these reactors still require user input to control each batch SODIS process and there is no feedback that the process is complete. Automatic operation of the batch SODIS process, controlled by UVA-radiation sensors, can provide information on the status of the process, can ensure the required UVA dose to achieve complete disinfection is received and reduces user work-load through automatic sequential batch processing. In this work, an enhanced CPC photo-reactor with a concentration factor of 1.89 was developed. The apparatus was automated to achieve exposure to a pre-determined UVA dose. Treated water was automatically dispensed into a reservoir tank. The reactor was tested using Escherichia coli as a model pathogen in natural well water. A 6-log inactivation of E. coli was achieved following exposure to the minimum uninterrupted lethal UVA dose. The enhanced reactor decreased the exposure time required to achieve the lethal UVA dose, in comparison to a CPC system with a concentration factor of 1.0. Doubling the lethal UVA dose prevented the need for a period of post-exposure dark inactivation and reduced the overall treatment time. Using this reactor, SODIS can be automatically carried out at an affordable cost, with reduced exposure time and minimal user input. Copyright © 2011 Elsevier B.V. All rights reserved.

RpoS Plays a Central Role in the SOS Induction by Sub-Lethal Aminoglycoside Concentrations in Vibrio cholerae

PubMed Central

Baharoglu, Zeynep; Krin, Evelyne; Mazel, Didier

2013-01-01

Bacteria encounter sub-inhibitory concentrations of antibiotics in various niches, where these low doses play a key role for antibiotic resistance selection. However, the physiological effects of these sub-lethal concentrations and their observed connection to the cellular mechanisms generating genetic diversification are still poorly understood. It is known that, unlike for the model bacterium Escherichia coli, sub-minimal inhibitory concentrations (sub-MIC) of aminoglycosides (AGs) induce the SOS response in Vibrio cholerae. SOS is induced upon DNA damage, and since AGs do not directly target DNA, we addressed two issues in this study: how sub-MIC AGs induce SOS in V. cholerae and why they do not do so in E. coli. We found that when bacteria are grown with tobramycin at a concentration 100-fold below the MIC, intracellular reactive oxygen species strongly increase in V. cholerae but not in E. coli. Using flow cytometry and gfp fusions with the SOS regulated promoter of intIA, we followed AG-dependent SOS induction. Testing the different mutation repair pathways, we found that over-expression of the base excision repair (BER) pathway protein MutY relieved this SOS induction in V. cholerae, suggesting a role for oxidized guanine in AG-mediated indirect DNA damage. As a corollary, we established that a BER pathway deficient E. coli strain induces SOS in response to sub-MIC AGs. We finally demonstrate that the RpoS general stress regulator prevents oxidative stress-mediated DNA damage formation in E. coli. We further show that AG-mediated SOS induction is conserved among the distantly related Gram negative pathogens Klebsiella pneumoniae and Photorhabdus luminescens, suggesting that E. coli is more of an exception than a paradigm for the physiological response to antibiotics sub-MIC. PMID:23613664

RpoS plays a central role in the SOS induction by sub-lethal aminoglycoside concentrations in Vibrio cholerae.

PubMed

Baharoglu, Zeynep; Krin, Evelyne; Mazel, Didier

2013-01-01

Bacteria encounter sub-inhibitory concentrations of antibiotics in various niches, where these low doses play a key role for antibiotic resistance selection. However, the physiological effects of these sub-lethal concentrations and their observed connection to the cellular mechanisms generating genetic diversification are still poorly understood. It is known that, unlike for the model bacterium Escherichia coli, sub-minimal inhibitory concentrations (sub-MIC) of aminoglycosides (AGs) induce the SOS response in Vibrio cholerae. SOS is induced upon DNA damage, and since AGs do not directly target DNA, we addressed two issues in this study: how sub-MIC AGs induce SOS in V. cholerae and why they do not do so in E. coli. We found that when bacteria are grown with tobramycin at a concentration 100-fold below the MIC, intracellular reactive oxygen species strongly increase in V. cholerae but not in E. coli. Using flow cytometry and gfp fusions with the SOS regulated promoter of intIA, we followed AG-dependent SOS induction. Testing the different mutation repair pathways, we found that over-expression of the base excision repair (BER) pathway protein MutY relieved this SOS induction in V. cholerae, suggesting a role for oxidized guanine in AG-mediated indirect DNA damage. As a corollary, we established that a BER pathway deficient E. coli strain induces SOS in response to sub-MIC AGs. We finally demonstrate that the RpoS general stress regulator prevents oxidative stress-mediated DNA damage formation in E. coli. We further show that AG-mediated SOS induction is conserved among the distantly related Gram negative pathogens Klebsiella pneumoniae and Photorhabdus luminescens, suggesting that E. coli is more of an exception than a paradigm for the physiological response to antibiotics sub-MIC.

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

Giggleman, M.A.; Fitzpatrick, L.C.; Goven, A.J.

Earthworms, Lumbricus terrestris, exposed for 96 h to filter paper saturated with five nominal concentrations of pentachlorophenol, exhibited a 50% lethal concentration (LC50) of 25.0 {micro}g PCP/cm{sup 2} and corresponding whole worm body burden-based 50% lethal dose (LD50) of 877.7 {micro}g PCP/g dry mass. Linear regression modeling showed that worms increased body concentrations (BC = {micro}g PCP/g dry tissue mass) with increasing exposure concentrations (EC) according to BC = 113.5 + 29.5EC. Phagocytosis of yeast cells by immunoactive coelomocytes was suppressed only at body concentrations (863.3 {micro}g PCP/g dry mass) that approximated the calculated LD50 and overlapped those demonstrating lethality,more » indicating a sharp transition between sublethal and lethal toxicity. An exposure concentration of 15 {micro}g PCP/cm{sup 2} produced significant suppression of phagocytosis of yeast cells by immunoactive coelomocytes. However, the average measured body burden from this group approximated the estimated LD50, indicating a sharp toxic response slope. Exposure to 10 {micro}g PCP/cm{sup 2} with a corresponding body concentration of 501.3 {micro}g PCP/g dry mass did not affect phagocytosis. The importance of body burden data is emphasized.« less

The Spatial Concentration of Southern Whites and Argument-Based Lethal Violence

ERIC Educational Resources Information Center

Lee, Matthew R.; Shihadeh, Edward S.

2009-01-01

This analysis examines how the spatial concentration of Southern whites is associated with white argument-based lethal violence. Using a well-known measure of spatial segregation (V, the adjusted P* index) among Southern-born whites in U.S. counties in 2000, the results reveal that the spatial concentration of Southern-born whites is only…

Oxidative stress in freshwater fish, Labeo rohita as a biomarker of malathion exposure.

PubMed

Patil, Vineetkumar K; David, Muniswamy

2013-12-01

This study examined the effect of lethal (4.5 μg/l) and sublethal (0.45 μg/l) malathion levels on oxidative stress responses of the freshwater edible fish, Labeo rohita. Fish were exposed to lethal (1-4 days) and sublethal (1, 5, 10, and 15 days) periods. In the present study, catalase and protease activity, hydrogen peroxide, malondialdehyde, protein carbonyls, and free amino acids levels increased in the gill, liver, and kidney tissues of fish exposed to lethal and sublethal concentrations of malathion except protein content. Time- and concentration-dependent induction/reduction of the above parameters by lethal and sublethal concentrations of malathion was observed in the tissues (the gill, liver, and kidney) of L. rohita. Thus, the results clearly infer oxidative damage and decline in antioxidant defense due to malathion-induced oxidative stress.

Estimations of the lethal and exposure doses for representative methanol symptoms in humans.

PubMed

Moon, Chan-Seok

2017-01-01

The aim of this review was to estimate the lethal and exposure doses of a representative symptom (blindness) of methanol exposure in humans by reviewing data from previous articles. Available articles published from 1970 to 2016 that investigated the dose-response relationship for methanol exposure (i.e., the exposure concentration and the biological markers/clinical symptoms) were evaluated; the MEDLINE and RISS (Korean search engine) databases were searched. The available data from these articles were carefully selected to estimate the range and median of a lethal human dose. The regression equation and correlation coefficient (between the exposure level and urinary methanol concentration as a biological exposure marker) were assumed from the previous data. The lethal human dose of pure methanol was estimated at 15.8-474 g/person as a range and as 56.2 g/person as the median. The dose-response relationship between methanol vapor in ambient air and urinary methanol concentrations was thought to be correlated. An oral intake of 3.16-11.85 g/person of pure methanol could cause blindness. The lethal dose from respiratory intake was reported to be 4000-13,000 mg/l. The initial concentration of optic neuritis and blindness were shown to be 228.5 and 1103 mg/l, respectively, for a 12-h exposure. The concentration of biological exposure indices and clinical symptoms for methanol exposure might have a dose-response relationship according to previous articles. Even a low dose of pure methanol through oral or respiratory exposure might be lethal or result in blindness as a clinical symptom.

Impact of non-constant concentration exposure on lethality of inhaled hydrogen cyanide.

PubMed

Sweeney, Lisa M; Sommerville, Douglas R; Channel, Stephen R

2014-03-01

The ten Berge model, also known as the toxic load model, is an empirical approach in hazard assessment modeling for estimating the relationship between the inhalation toxicity of a chemical and the exposure duration. The toxic load (TL) is normally expressed as a function of vapor concentration (C) and duration (t), with TL equaling C(n) × t being a typical form. Hypothetically, any combination of concentration and time that yields the same "toxic load" will give a constant biological response. These formulas have been developed and tested using controlled, constant concentration animal studies, but the validity of applying these assumptions to time-varying concentration profiles has not been tested. Experiments were designed to test the validity of the model under conditions of non-constant acute exposure. Male Sprague-Dawley rats inhaled constant or pulsed concentrations of hydrogen cyanide (HCN) generated in a nose-only exposure system for 5, 15, or 30 min. The observed lethality of HCN for the 11 different C versus t profiles was used to evaluate the ability of the model to adequately describe the lethality of HCN under the conditions of non-constant inhalation exposure. The model was found to be applicable under the tested conditions, with the exception of the median lethality of very brief, high concentration, discontinuous exposures.

Chemical composition and antifungal activity of essential oils and supercritical CO2 extracts of Apium nodiflorum (L.) Lag.

PubMed

Maxia, Andrea; Falconieri, Danilo; Piras, Alessandra; Porcedda, Silvia; Marongiu, Bruno; Frau, Maria Assunta; Gonçalves, Maria J; Cabral, Célia; Cavaleiro, Carlos; Salgueiro, Lígia

2012-07-01

Aerial parts of Apium nodiflorum collected in Portugal and Italy were submitted to hydrodistillation; also a supercritical fluid extract was obtained from Italian plants. The extracts were analyzed by GC and GC/MS. Both essential oils, obtained from Portuguese and Italian plants, posses high content of phenylpropanoids (51.6 vs. 70.8%); in the former, the percentage split in myristicin (29.1%) and dillapiol (22.5%), whereas in the latter, the total percentage is only of dillapiol (70.8%). The co-occurrence of myristicin and dillapiol is frequent because dillapiol results from enzymatic methoxylation of myristicin. Antimicrobial activity of phenylpropanoids has been patented, what suggest the potential of plants with high amounts of these compounds. Minimal inhibitory concentration (MIC) and minimal lethal concentration, determined according to NCCLS, were used to evaluate the antifungal activity of the essential oils against yeasts, Aspergillus species and dermatophytes. Essential oils exhibited higher antifungal activity than other Apiaceae against dermatophytes, with MIC ranging from 0.04 to 0.32 μl/ml. These results support the potential of A. nodiflorum oil in the treatment of dermatophytosis and candidosis.

Chemical composition and antifungal activity of the essential oils of Lavandula pedunculata (Miller) Cav.

PubMed

Zuzarte, Monica; Gonçalves, Maria J; Cavaleiro, Carlos; Dinis, Augusto M; Canhoto, Jorge M; Salgueiro, Lígia R

2009-08-01

The chemical composition and antifungal activity of the essential oils of Lavandula pedunculata (Miller) Cav., harvested in North and Central Portugal, were investigated. The essential oils were isolated by hydrodistillation and analyzed by GC and GC/MS. The minimal-inhibitory concentration (MIC) and the minimal-lethal concentration (MLC) of the essential oils and of their major constituents were used to evaluate the antifungal activity against different strains of fungi involved in candidosis, dematophytosis, and aspergillosis. The oils were characterized by a high percentage of oxygenated monoterpenes, the main compounds being 1,8-cineole (2.4-55.5%), fenchone (1.3-59.7%), and camphor (3.6-48.0%). Statistical analysis differentiated the essential oils into two main types, one characterized by the predominance of fenchone and the other one by the predominance of 1,8-cineole. Within the 1,8-cineole chemotype, two subgroups were well-defined taking into account the percentages of camphor. A significant antifungal activity of the oils was found against dermatophyte strains. The essential oil with the highest content of camphor was the most active with MIC and MLC values ranging from 0.32-0.64 microl/ml.

Chemoprevention by thyme oils of Aspergillus parasiticus growth and aflatoxin production.

PubMed

Rasooli, Iraj; Owlia, Parviz

2005-12-01

The essential oils from Thymus eriocalyx and Thymus X-porlock obtained by hydrodistillation were analyzed by GC/MS. The major components of T. eriocalyx and T. X-porlock oils were thymol (63.8, 31.7%), beta-phellandrene (13.30, 38.7%), cis-sabinene hydroxide (8.1, 9.6%), 1,8-cineole (2, 1.7%), and beta-pinene (1.31, 2%), respectively. Antifungal activities of the oils were studied with special reference to the inhibition of Aspergillus parasiticus growth and aflatoxin production. Minimal inhibitory (MIC) and minimal fungicidal (MFC) concentrations of the oils were determined. Static effects of the above oils against A. parasiticus were at 250 ppm and lethal effects of T. eriocalyx and T. X-porlock were 500 and 1000 ppm of the oils, respectively. Aflatoxin production was inhibited at 250 ppm of both oils with that of T. eriocalyx being stronger inhibitor. Transmission electron microscopy (TEM) of A. parasiticus exposed to MIC level (250 ppm) of the oils showed irreversible damage to cell wall, cell membrane, and cellular organelles. It is concluded that the essential oils could be safely used as preservative materials on some kinds of foods at low concentrations to protect them from fungal infections.

CARFILZOMIB INTERACTS SYNERGISTICALY WITH HISTONE DEACETYLASE INHIBITORS IN MANTLE CELL LYMPHOMA CELLS IN VITRO AND IN VIVO

PubMed Central

Dasmahapatra, Girija; Lembersky, Dmitry; Son, Minkyeong P.; Attkisson, Elisa; Dent, Paul; Fisher, Richard. I.; Friedberg, Jonathan W.; Grant, Steven

2011-01-01

Interactions between the proteasome inhibitor carfilzomib and the HDAC inhibitors vorinostat and SNDX-275 were examined in mantle cell lymphoma (MCL) cells in vitro and in vivo. Co-administration of very low, marginally toxic carfilzomib concentrations (e.g., 3–4 nM) with minimally lethal vorinostat or SNDX-275 concentrations induced sharp increases in mitochondrial injury and apoptosis in multiple MCL cell lines and primary MCL cells. Enhanced lethalitly was associated with JNK1/2 activation, increased DNA damage (induction of λH2A.X), and ERK1/2 and AKT1/2 inactivation. Co-administration of carfilzomib and HDACIs induced a marked increase in ROS generation, and G2M arrest. Significantly, the free radical scavenger TBAP blocked carfilzomib/HDACI-mediated ROS generation, λH2A.X formation, JNK1/2 activation, and lethality. Genetic (shRNA) knock down of JNK1/2 significantly attenuated carfilzomib/HDACI-induced apoptosis, but did not prevent ROS generation or DNA damage. Carfilzomib/HDACI regimens were also active against bortezomib-resistant MCL cells. Finally, carfilzomib/vorinostat co-administrationo resulted in a pronounced reduction in tumor growth compared to single agent treatment in a MCL xenograft model associated with enhanced apoptosis, λH2A.X formation, and JNK activation. Collectively, these findings suggest that carfilzomib/HDACI regimens warrants attention in MCL. PMID:21750224

Enhanced effect of gap junction uncouplers on macroscopic electrical properties of reperfused myocardium

PubMed Central

Rodriguez-Sinovas, Antonio; García-Dorado, David; Ruiz-Meana, Marisol; Soler-Soler, Jordi

2004-01-01

Transient inhibition of gap junction (GJ)-mediated communication with heptanol during myocardial reperfusion limits infarct size. However, inhibition of cell coupling in normal myocardium may be arrhythmogenic. The purpose of this study was to test the hypothesis that the consequences of GJ inhibition may be magnified in reperfused myocardium compared with normal tissue, thus allowing the inhibition of GJs in reperfused tissue while only minimally modifying overall macroscopic cell coupling in normal myocardium. Concentration–response curves were defined for the effects of heptanol, 18α-glycyrrhetinic acid, halothane, and palmitoleic acid on conduction velocity, tissue electrical impedance, developed tension and lactate dehydrogenase (LDH) release in normoxically perfused rat hearts (n = 17). Concentrations lacking significant effects on tissue impedance were added during the initial 15 min of reperfusion in hearts submitted to 60 min (n = 43) or 30 min (n = 35) of ischaemia. These concentrations markedly increased myocardial electrical impedance (resistivity and phase angle) in myocardium reperfused after either 30 or 60 min of ischaemia, and reduced reperfusion-induced LDH release after 1 h of ischaemia by 83.6, 57.9, 51.7 and 52.5% for heptanol, 18α-glycyrrhetinic acid, halothane and palmitoleic acid, respectively. LDH release was minimal in hearts submitted to 30 min of ischaemia, independently of group allocation. In conclusion, the present results strongly support the hypothesis that intercellular communication in postischaemic myocardium may be effectively reduced by concentrations of GJ inhibitors affecting only minimally overall electrical impedance in normal myocardium. Reduction of cell coupling during initial reperfusion was consistently associated with attenuated lethal reperfusion injury. PMID:15218064

Use of pellet guns for crowd control in Kashmir: How lethal is "non-lethal"?

PubMed

David, Siddarth

2017-01-01

The use of pellet guns during the recent unrest in Kashmir as a method of crowd control has been questioned because of several deaths and numerous injuries. Across the world, these rubber pellets have been shown to inflict serious injuries, permanent disability, and death. The volatility of mob violence, inaccuracies in aim of the pellets, over-use of the pellet guns, and the perception of their harmlessness enhances the destructive potential of these so-called non-lethal weapons. There is also the larger ethical question whether any form of pain, however minimal, could be inflicted to control violent crowds.

Response of the Cottonwood Leaf Beetle (Coleoptera: Chrysomelidae) to Bacillus thuringiensis var. san diego

Treesearch

Leah S. Bauer

1990-01-01

A standardized laboratory bioassay was used to quantify the lethal and sub-lethal responses of larval and adult cottonwood leaf beetles, Chrysomela scripta F., to Bacillus thuringiensis var. san diego, formulated as M-One standard powder (Mycogen Corporation, San Diego). The median lethal concentration (LC

The Future Combat System: Minimizing Risk While Maximizing Capability

DTIC Science & Technology

2000-05-01

ec /W hl Co nv /T ra ck Co nv /W hl El ec /T rac El ec /W hl Crew &Misc Power Mgt Propulsion Lethality Structure /Surviv Conv / ETC Lethality Missile...also examines the wheeled versus tracked debate. The paper concludes by recommending some of the technologies for further development under a parallel...versus tracked debate. The paper concludes by recommending some of the technologies for further development under a parallel acquisition strategy

Chronic toxicity of copper to five benthic invertebrates in laboratory-formulated sediment: sensitivity comparison and preliminary risk assessment.

PubMed

Roman, Yblin E; De Schamphelaere, Karel A C; Nguyen, Lien T H; Janssen, Colin R

2007-11-15

Five benthic organisms commonly used for sediment toxicity testing were chronically (28 to 35 days) exposed to copper in standard laboratory-formulated sediment (following Organization for Economic Cooperation and Development guidelines) and lethal and sub-lethal toxicities were evaluated. Sub-lethal endpoints considered were reproduction and biomass production for Lumbriculus variegatus, growth and reproduction for Tubifex tubifex, growth and emergence for Chironomus riparius, and growth for Gammarus pulex and Hyalella azteca. Expressed on whole-sediment basis the observed lethal sensitivity ranking (from most to least sensitive) was: G. pulex>L. variegatus>H. azteca=C. riparius=T. tubifex, with median chronic lethal concentrations (LC50) between 151 and 327 mg/kg dry wt. The sub-lethal sensitivity ranking (from most to least sensitive, with the most sensitive endpoint between parentheses): C. riparius (emergence)>T. tubifex (reproduction)=L. variegatus (reproduction)>G. pulex (growth)>H. azteca (growth), with median effective concentrations (EC50) between 59.2 and 194 mg/kg dry wt. No observed effect concentrations (NOEC) or 10% effective concentrations (EC10) for the five benthic invertebrates were used to perform a preliminary risk assessment for copper in freshwater sediment by means of (a) the "assessment factor approach" or (b) the statistical extrapolation approach (species sensitivity distribution). Depending on the data (NOEC or EC10) and the methodology used, we calculated a Predicted No Effect Concentration (PNEC) for sediment between 3.3 and 47.1 mg Cu/dry wt. This range is similar to the range of natural (geochemical) background concentrations of copper in sediments in Europe, i.e. 90% of sediments have a concentration between 5 and 49 mg Cu/kg dry wt. A detailed analysis of the outcome of this preliminary exercise highlighted that multiple issues need to be explored for achieving a scientifically more sound risk assessment and for the development of robust sediment quality criteria for copper, including (i) the use of the assessment factor approach vs. the statistical extrapolation approach, (ii) the importance of bioavailability modifying factors (e.g., organic carbon, acid volatile sulfide), and (iii) the influence of prevailing geochemical (bioavailable) background concentrations on the copper sensitivity of local benthic biota.

Seasonal variation in abiotic factors and ferulic acid toxicity in snail-attractant pellets against the intermediate host snail Lymnaea acuminata.

PubMed

Agrahari, P; Singh, D K

2013-11-01

Laboratory evaluation was made to access the seasonal variations in abiotic environmental factors temperature, pH, dissolved oxygen, carbon dioxide, electrical conductivity and ferulic acid toxicity in snail-attractant pellets (SAP) against the intermediate host snail Lymnaea acuminata in each month of the years 2010 and 2011. On the basis of a 24-h toxicity assay, it was noted that lethal concentration values of 4.03, 3.73% and 4.45% in SAP containing starch and 4.16, 4.23% and 4.29% in SAP containing proline during the months of May, June and September, respectively, were most effective in killing the snails, while SAP containing starch/proline + ferulic acid was least effective in the month of January/February (24-h lethal concentration value was 7.67%/7.63% in SAP). There was a significant positive correlation between lethal concentration value of ferulic acid containing SAP and levels of dissolved O2 /pH of water in corresponding months. On the contrary, a negative correlation was observed between lethal concentration value and dissolved CO2 /temperature of test water in the same months. To ascertain that such a relationship between toxicity and abiotic factors is not co-incidental, the nervous tissue of treated (40% and 80% of 24-h lethal concentration value) and control group of snails was assayed for the activity of acetylcholinesterase (AChE) in each of the 12 months of the same year. There was a maximum inhibition of 58.43% of AChE, in snails exposed to 80% of the 24-h lethal concentration value of ferulic acid + starch in the month of May. This work shows conclusively that the best time to control snail population with SAP containing ferulic acid is during the months of May, June and September. © 2012 Blackwell Verlag GmbH.

An evaluation of the toxicity of potassium chloride, active compound in the molluscicide potash, on salmonid fish and their forage base

USGS Publications Warehouse

Densmore, Christine L.; Iwanowicz, Luke R.; Henderson, Anne P.; Blazer, Vicki S.; Reed-Grimmett, Baileigh M.; Sanders, Lakyn R.

2018-06-29

Potash, with the active ingredient potassium chloride (KCl) is a chemical that is currently being evaluated for potential use as a molluscicide to combat invasive zebra mussels and quagga mussels in Western United States waters. Although data available for other freshwater fishes indicate that recommended treatment levels of potash as a molluscicide are sublethal, this has not been demonstrated for all salmonid species. The objectives of this study were to perform toxicity testing to determine the lethality of potassium chloride against selected species of salmonid fish (brook trout and Chinook salmon) and selected invertebrate forage, and to identify any potential adverse physiological impacts of KCl to these salmonids in water at treatment levels used for mollusk eradication. Minimal mortality (n=1 fish) was observed during 96-hour toxicity testing at KCl concentrations of 0 to 800 milligrams per liter (mg/L), indicating that the lethal concentration (LC50) values in these salmonid species were considerably higher than realistic molluscicide treatment concentrations. Sublethal effects were examined through evaluation of behavioral and morphological (histological) observation as well as specific blood chemistry parameters (electrolytes, osmolality, glucose, and cortisol). There was no strong evidence of significant physiological impairment among the two salmonid species due to KCl exposure. Whereas statistically significant differences in some parameters were observed in association with KCl treatments, it is unlikely that these differences indicate adverse biological impacts. Acute toxicity tests were conducted with invertebrate species at KCl exposure concentrations of 0–3,200 mg/L. Daphniid exposure trials resulted in differences in mortality among the test groups with higher mortality evident among the higher KCl exposure concentrations with a calculated LC50 value of 196 mg/L KCl for a 48-hour exposure. Crayfish exposed to higher concentrations of KCl at or above 800 mg/L as specimens exhibited death or reversible paralysis. Chironomid larvae exposures were largely inconclusive because of cannibalistic behavior among the various test groups.

Sodium cyanide induced alteration in the whole animal oxygen consumption and behavioural pattern of freshwater fish Labeo rohita.

PubMed

David, Muniswamy; Sangeetha, Jeyabalan; Harish, Etigemane R

2015-03-01

Sodium cyanide is a common environmental pollutant which is mainly used in many industries such as mining, electroplating, steel manufacturing, pharmaceutical production and other specialized applications including dyes and agricultural products. It enters aquatic environment through effluents from these industries. Static renewal bioassay test has been conducted to determine LC, of sodium cyanide on indigenous freshwater carp, Labeo rohita. The behavioural pattern and oxygen consumption were observed in fish at both lethal and sub lethal concentrations. Labeo rohita in toxic media exhibited irregular and erratic swimming movements, hyper excitability, loss of equilibrium and shrinking to the bottom, which may be due to inhibition of cytochrome C oxidase activity and decreased blood pH. The combination of cytotoxic hypoxia with lactate acidosis depresses the central nervous system resulting in respiratory arrest and death. Decrease in oxygen consumption was observed at both lethal and sub lethal concentrations of sodium cyanide. Mortality was insignificant at sub lethal concentration test when fishes were found under stress. Consequence of impaired oxidative metabolism and elevated physiological response by fish against sodium cyanide stress showed alteration in respiratory rate.

Lethal morphine intoxication in a patient with a sickle cell crisis and renal impairment: case report and a review of the literature.

PubMed

Lagas, Jurjen S; Wagenaar, Jiri F P; Huitema, Alwin D R; Hillebrand, Michel J X; Koks, Cornelis H W; Gerdes, Victor E A; Brandjes, Desiderius P M; Beijnen, Jos H

2011-09-01

Morphine-6-glucuronide, the active metabolite of morphine, and to a lesser extent morphine itself are known to accumulate in patients with renal failure. A number of cases on non-lethal morphine toxicity in patients with renal impairment report high plasma concentrations of morphine-6-glucuronide, suggesting that this metabolite achieves sufficiently high brain concentrations to cause long-lasting respiratory depression, despite its poor central nervous system penetration. We report a lethal morphine intoxication in a 61-year-old man with sickle cell disease and renal impairment, and we measured concentrations of morphine and morphine-6-glucuronide in blood, brain and cerebrospinal fluid. There were no measurable concentrations of morphine-6-glucuronide in cerebrospinal fluid or brain tissue, despite high blood concentrations. In contrast, the relatively high morphine concentration in the brain suggests that morphine itself was responsible for the cardiorespiratory arrest in this patient. Given the fatal outcome, we recommend to avoid repeated or continuous morphine administration in renal failure.

Correlation of Lethal Concentrations of Heavy Metals with Tissue Levels of Earthworms

DTIC Science & Technology

1988-08-01

mentioned in the contract i.e. mercury , arsenic, ’cadmium and copper. We will find out the 50 % lethal concentrations (LC50) and the smallest...concentrations, blanks, and background worm stock has been limited to copper and cadmium. In fact, mercury and arsenic request special analytical device...the other boxes but without toxic components. Contaminants to study are heavy metals : cadmium, copper and mercury , and arsenic. We chose following

Assessing Toxicity of Obscurant Grade Pan-Based Carbon Fiber Aquatic Species Chronic Tests

DTIC Science & Technology

2004-12-01

ASSESSING TOXICITY OF OBSCURANT GRADE PAN-BASED CARBON FIBER: AQUATIC SPECIES CHRONIC TESTS N. A. Chester, M. V. Haley, C. W. Kurnas and R. T...with minimal restrictions. To this end we are investigating the toxicity of PAN-based carbon fibers to the aquatic species Ceriodaphnia dubia (water... toxicity methods to provide ecotoxicological results for both lethal and sub-lethal parameters, including LC50 (24-, 48- and 96-h), IC50, EC20, and

Immobilized Hydrolytic Enzymes Exhibit Antibiofilm Activity Against Escherichia coli at Sub-Lethal Concentrations.

PubMed

Villa, Federica; Secundo, Francesco; Polo, Andrea; Cappitelli, Francesca

2015-07-01

The effects of two commercially available immobilized enzymes (namely the glycosidase pectinase and the protease subtilisin A) at sub-lethal concentrations were investigated in terms of their influence on biofilm genesis, on the composition of the biofilm matrix, and their antibiotic synergy against Escherichia coli biofilm, used as a model system of bacterial biofilms. The best antibiofilm performance of solid-supported hydrolases was obtained at the surface concentration of 0.022 and 0.095 U/cm(2) with a reduction of 1.2 and 2.3 log CFU/biofilm for pectinase and subtilisin, respectively. At these enzyme surface concentrations, the biocatalysts affected the structural composition of the biofilm matrix, impacting biofilm thickness. Finally, the immobilized hydrolases enhanced biofilm sensitivity to a clinically relevant concentration of the antibiotic ampicillin. At the final antibiotic concentration of 0.1 mg/ml, a reduction of 2 and 3.5 log10 units in presence of 0.022 Upectinase/cm(2) and 0.095 Usubtilisin/cm(2) was obtained, respectively, in comparison the antibiotic alone. Immobilized pectinase and subtilisin at sub-lethal concentrations demonstrated a great potential for antibiofilm applications.

Suppressing bullfrog larvae with carbon dioxide

USGS Publications Warehouse

Gross, Jackson A.; Ray, Andrew; Sepulveda, Adam J.; Watten, Barnaby J.; Densmore, Christine L.; Layhee, Megan J.; Mark Abbey-Lambert,; ,

2014-01-01

Current management strategies for the control and suppression of the American Bullfrog (Lithobates catesbeianus = Rana catesbeiana Shaw) and other invasive amphibians have had minimal effect on their abundance and distribution. This study evaluates the effects of carbon dioxide (CO2) on pre- and prometamorphic Bullfrog larvae. Bullfrogs are a model organism for evaluating potential suppression agents because they are a successful invader worldwide. From experimental trials we estimated that the 24-h 50% and 99% lethal concentration (LC50 and LC99) values for Bullfrog larvae were 371 and 549 mg CO2/L, respectively. Overall, larvae that succumbed to experimental conditions had a lower body condition index than those that survived. We also documented sublethal changes in blood chemistry during prolonged exposure to elevated CO2. Specifically, blood pH decreased by more than 0.5 pH units after 9 h of exposure and both blood partial pressure of CO2 (pCO2) and blood glucose increased. These findings suggest that CO2 treatments can be lethal to Bullfrog larvae under controlled laboratory conditions. We believe this work represents the necessary foundation for further consideration of CO2 as a potential suppression agent for one of the most harmful invaders to freshwater ecosystems.

Hypericum perforatum Reduces Paracetamol-Induced Hepatotoxicity and Lethality in Mice by Modulating Inflammation and Oxidative Stress.

PubMed

Hohmann, Miriam S N; Cardoso, Renato D R; Fattori, Victor; Arakawa, Nilton S; Tomaz, José C; Lopes, Norberto P; Casagrande, Rubia; Verri, Waldiceu A

2015-07-01

Hypericum perforatum is a medicinal plant with anti-inflammatory and antioxidant properties, which is commercially available for therapeutic use in Brazil. Herein the effect of H. perforatum extract on paracetamol (acetaminophen)-induced hepatotoxicity, lethality, inflammation, and oxidative stress in male swiss mice were investigated. HPLC analysis demonstrated the presence of rutin, quercetin, hypericin, pseudohypericin, and hyperforin in H. perforatum extract. Paracetamol (0.15-3.0 g/kg, p.o.) induced dose-dependent mortality. The sub-maximal lethal dose of paracetamol (1.5 g/kg, p.o.) was chosen for the experiments in the study. H. perforatum (30-300 mg/kg, i.p.) dose-dependently reduced paracetamol-induced lethality. Paracetamol-induced increase in plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) concentrations, and hepatic myeloperoxidase activity, IL-1β, TNF-α, and IFN-γ concentrations as well as decreased reduced glutathione (GSH) concentrations and capacity to reduce 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate radical cation; ABTS˙(+) ) were inhibited by H. perforatum (300 mg/kg, i.p.) treatment. Therefore, H. perforatum protects mice against paracetamol-induced lethality and liver damage. This effect seems to be related to the reduction of paracetamol-induced cytokine production, neutrophil recruitment, and oxidative stress. Copyright © 2015 John Wiley & Sons, Ltd.

An analysis of lethal and sublethal interactions among type I and type II pyrethroid pesticide mixtures using standard Hyalella azteca water column toxicity tests.

PubMed

Hoffmann, Krista Callinan; Deanovic, Linda; Werner, Inge; Stillway, Marie; Fong, Stephanie; Teh, Swee

2016-10-01

A novel 2-tiered analytical approach was used to characterize and quantify interactions between type I and type II pyrethroids in Hyalella azteca using standardized water column toxicity tests. Bifenthrin, permethrin, cyfluthrin, and lambda-cyhalothrin were tested in all possible binary combinations across 6 experiments. All mixtures were analyzed for 4-d lethality, and 2 of the 6 mixtures (permethrin-bifenthrin and permethrin-cyfluthrin) were tested for subchronic 10-d lethality and sublethal effects on swimming motility and growth. Mixtures were initially analyzed for interactions using regression analyses, and subsequently compared with the additive models of concentration addition and independent action to further characterize mixture responses. Negative interactions (antagonistic) were significant in 2 of the 6 mixtures tested, including cyfluthrin-bifenthrin and cyfluthrin-permethrin, but only on the acute 4-d lethality endpoint. In both cases mixture responses fell between the additive models of concentration addition and independent action. All other mixtures were additive across 4-d lethality, and bifenthrin-permethrin and cyfluthrin-permethrin were also additive in terms of subchronic 10-d lethality and sublethal responses. Environ Toxicol Chem 2016;35:2542-2549. © 2016 SETAC. © 2016 SETAC.

Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification

PubMed Central

Huang, Haishui; Choi, Jung Kyu; Rao, Wei; Zhao, Shuting; Agarwal, Pranay; Zhao, Gang

2015-01-01

Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification (i.e., no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification (i.e., formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants (i.e., high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 μl) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 μl, large volume). PMID:26640426

Alginate Hydrogel Microencapsulation Inhibits Devitrification and Enables Large-Volume Low-CPA Cell Vitrification.

PubMed

Huang, Haishui; Choi, Jung Kyu; Rao, Wei; Zhao, Shuting; Agarwal, Pranay; Zhao, Gang; He, Xiaoming

2015-11-25

Cryopreservation of stem cells is important to meet their ever-increasing demand by the burgeoning cell-based medicine. The conventional slow freezing for stem cell cryopreservation suffers from inevitable cell injury associated with ice formation and the vitrification ( i.e. , no visible ice formation) approach is emerging as a new strategy for cell cryopreservation. A major challenge to cell vitrification is intracellular ice formation (IIF, a lethal event to cells) induced by devitrification ( i.e. , formation of visible ice in previously vitrified solution) during warming the vitrified cells at cryogenic temperature back to super-zero temperatures. Consequently, high and toxic concentrations of penetrating cryoprotectants ( i.e. , high CPAs, up to ~8 M) and/or limited sample volumes (up to ~2.5 μl) have been used to minimize IIF during vitrification. We reveal that alginate hydrogel microencapsulation can effectively inhibit devitrification during warming. Our data show that if ice formation were minimized during cooling, IIF is negligible in alginate hydrogel-microencapsulated cells during the entire cooling and warming procedure of vitrification. This enables vitrification of pluripotent and multipotent stem cells with up to ~4 times lower concentration of penetrating CPAs (up to 2 M, low CPA) in up to ~100 times larger sample volume (up to ~250 μl, large volume).

Body burdens of heavy metals in Lake Michigan wetland turtles.

PubMed

Smith, Dayna L; Cooper, Matthew J; Kosiara, Jessica M; Lamberti, Gary A

2016-02-01

Tissue heavy metal concentrations in painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles from Lake Michigan coastal wetlands were analyzed to determine (1) whether turtles accumulated heavy metals, (2) if tissue metal concentrations were related to environmental metal concentrations, and (3) the potential for non-lethal sampling techniques to be used for monitoring heavy metal body burdens in freshwater turtles. Muscle, liver, shell, and claw samples were collected from painted and snapping turtles and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc. Turtle tissues had measurable quantities of all eight metals analyzed. Statistically significant correlations between tissue metal concentrations and sediment metal concentrations were found for a subset of metals. Metals were generally found in higher concentrations in the larger snapping turtles than in painted turtles. In addition, non-lethal samples of shell and claw were found to be possible alternatives to lethal liver and muscle samples for some metals. Human consumption of snapping turtles presents potential health risks if turtles are harvested from contaminated areas. Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems.

Sub-lethal and lethal toxicities of elevated CO2 on embryonic, juvenile, and adult stages of marine medaka Oryzias melastigma.

PubMed

Lee, Changkeun; Kwon, Bong-Oh; Hong, Seongjin; Noh, Junsung; Lee, Junghyun; Ryu, Jongseong; Kang, Seong-Gil; Khim, Jong Seong

2018-06-06

The potential leakage from marine CO 2 storage sites is of increasing concern, but few studies have evaluated the probable adverse effects on marine organisms. Fish, one of the top predators in marine environments, should be an essential representative species used for water column toxicity testing in response to waterborne CO 2 exposure. In the present study, we conducted fish life cycle toxicity tests to fully elucidate CO 2 toxicity mechanism effects. We tested sub-lethal and lethal toxicities of elevated CO 2 concentrations on marine medaka (Oryzias melastigma) at different developmental stages. At each developmental stage, the test species was exposed to varying concentrations of gaseous CO 2 (control air, 5%, 10%, 20%, and 30%), with 96 h of exposure at 0-4 d (early stage), 4-8 d (middle stage), and 8-12 d (late stage). Sub-lethal and lethal effects, including early developmental delays, cardiac edema, tail abnormalities, abnormal pigmentation, and mortality were monitored daily during the 14 d exposure period. At the embryonic stage, significant sub-lethal and lethal effects were observed at pH < 6.30. Hypercapnia can cause long-term and/or delayed developmental embryonic problems, even after transfer back to clean seawater. At fish juvenile and adult stages, significant mortality was observed at pH < 5.70, indicating elevated CO 2 exposure might cause various adverse effects, even during short-term exposure periods. It should be noted the early embryonic stage was found more sensitive to CO 2 exposure than other developmental stages of the fish life cycle. Overall, the present study provided baseline information for potential adverse effects of high CO 2 concentration exposure on fish developmental processes at different life cycle stages in marine ecosystems. Copyright © 2018 Elsevier Ltd. All rights reserved.

Assessment of the lethal and sublethal effects of 20 environmental chemicals in zebrafish embryos and larvae by using OECD TG 212.

PubMed

Horie, Yoshifumi; Yamagishi, Takahiro; Takahashi, Hiroko; Shintaku, Youko; Iguchi, Taisen; Tatarazako, Norihisa

2017-10-01

Fish embryo toxicity tests are used to assess the lethal and sublethal effects of environmental chemicals in aquatic organisms. Previously, we used a short-term toxicity test published by the Organization for Economic Co-operation and Development (test no. 212: Fish, Short-term Toxicity Test on Embryo and Sac-Fry Stages [OECD TG 212]) to assess the lethal and sublethal effects of aniline and several chlorinated anilines in zebrafish embryos and larvae. To expand upon this previous study, we used OECD TG 212 in zebrafish embryos and larvae to assess the lethal and sublethal effects of 20 additional environmental chemicals that included active pharmaceutical ingredients, pesticides, metals, aromatic compounds or chlorinated anilines. Zebrafish embryos (Danio rerio) were exposed to the test chemicals until 8 days post-fertilization. A delayed lethal effect was induced by 16 of the 20 test chemicals, and a positive correlation was found between heart rate turbulence and mortality. We also found that exposure to the test chemicals at concentrations lower than the lethal concentration induced the sublethal effects of edema, body curvature and absence of swim-bladder inflation. In conclusion, the environmental chemicals assessed in the present study induced both lethal and sublethal effects in zebrafish embryos and larvae, as assessed by using OECD TG 212. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Prediction of lethal/effective concentration/dose in the presence of multiple auxiliary covariates and components of variance

USGS Publications Warehouse

Gutreuter, S.; Boogaard, M.A.

2007-01-01

Predictors of the percentile lethal/effective concentration/dose are commonly used measures of efficacy and toxicity. Typically such quantal-response predictors (e.g., the exposure required to kill 50% of some population) are estimated from simple bioassays wherein organisms are exposed to a gradient of several concentrations of a single agent. The toxicity of an agent may be influenced by auxiliary covariates, however, and more complicated experimental designs may introduce multiple variance components. Prediction methods lag examples of those cases. A conventional two-stage approach consists of multiple bivariate predictions of, say, medial lethal concentration followed by regression of those predictions on the auxiliary covariates. We propose a more effective and parsimonious class of generalized nonlinear mixed-effects models for prediction of lethal/effective dose/concentration from auxiliary covariates. We demonstrate examples using data from a study regarding the effects of pH and additions of variable quantities 2???,5???-dichloro-4???- nitrosalicylanilide (niclosamide) on the toxicity of 3-trifluoromethyl-4- nitrophenol to larval sea lamprey (Petromyzon marinus). The new models yielded unbiased predictions and root-mean-squared errors (RMSEs) of prediction for the exposure required to kill 50 and 99.9% of some population that were 29 to 82% smaller, respectively, than those from the conventional two-stage procedure. The model class is flexible and easily implemented using commonly available software. ?? 2007 SETAC.

Lethal exposure: An integrated approach to pathogen transmission via environmental reservoirs.

PubMed

Turner, Wendy C; Kausrud, Kyrre L; Beyer, Wolfgang; Easterday, W Ryan; Barandongo, Zoë R; Blaschke, Elisabeth; Cloete, Claudine C; Lazak, Judith; Van Ert, Matthew N; Ganz, Holly H; Turnbull, Peter C B; Stenseth, Nils Chr; Getz, Wayne M

2016-06-06

To mitigate the effects of zoonotic diseases on human and animal populations, it is critical to understand what factors alter transmission dynamics. Here we assess the risk of exposure to lethal concentrations of the anthrax bacterium, Bacillus anthracis, for grazing animals in a natural system over time through different transmission mechanisms. We follow pathogen concentrations at anthrax carcass sites and waterholes for five years and estimate infection risk as a function of grass, soil or water intake, age of carcass sites, and the exposure required for a lethal infection. Grazing, not drinking, seems the dominant transmission route, and transmission is more probable from grazing at carcass sites 1-2 years of age. Unlike most studies of virulent pathogens that are conducted under controlled conditions for extrapolation to real situations, we evaluate exposure risk under field conditions to estimate the probability of a lethal dose, showing that not all reservoirs with detectable pathogens are significant transmission pathways.

Effects of a low-radiotoxicity uranium salt (uranyl acetate) on biochemical and hematological parameters of the catfish, Clarias gariepinus

NASA Astrophysics Data System (ADS)

Al-Ghanim, Khalid A.; Ahmad, Zubair; Al-Kahem Al-Balawi, Hmoud F.; Al-Misned, Fahad; Maboob, Shahid; Suliman, El-Amin M.

2016-01-01

Specimens of Clarias gariepinus were treated with lethal (70, 75, 80, 85, 90, and 95 mg/L) and sub-lethal concentrations (8, 12 and 16 mg/L) of uranyl acetate, a low-radiotoxicity uranium salt. The LC 50 value was registered as 81.45 mg/L. The protein and glycogen concentrations in liver and muscles were decreased in the fish exposed to sub-lethal concentrations. The red blood cell (RBC) and white blood cell (WBC) counts, haemoglobin (Hb) concentration and haematocrit (Hct) values were decreased. Different blood indices like mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were negatively affected. Level of plasma glucose was elevated whereas protein was decreased. The level of calcium concentration (Ca) was declined in the blood of exposed fish whereas magnesium (Mg) remains unchanged. The activity level of glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) was elevated in exposed fish. These effects were more pronounced in the last period of exposure and in higher concentrations. Results of the present study indicate that uranyl acetate has adverse effects on Clarias gariepinus and causes changes in the biochemical and hematological parameters of the fish.

Antifungal activity of phenolic-rich Lavandula multifida L. essential oil.

PubMed

Zuzarte, M; Vale-Silva, L; Gonçalves, M J; Cavaleiro, C; Vaz, S; Canhoto, J; Pinto, E; Salgueiro, L

2012-07-01

This study evaluates the antifungal activity and mechanism of action of a new chemotype of Lavandula multifida from Portugal. The essential oil was analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS), and the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) of the oil and its major compounds were determined against several pathogenic fungi responsible for candidosis, meningitis, dermatophytosis, and aspergillosis. The influence of the oil on the dimorphic transition in Candida albicans was also studied, as well as propidium iodide (PI) and FUN-1 staining of C. albicans cells by flow cytometry. The essential oil was characterized by high contents of monoterpenes, with carvacrol and cis-β-ocimene being the main constituents. The oil was more effective against dermatophytes and Cryptococcus neoformans, with MIC and MLC values of 0.16 μL/mL and 0.32 μL/mL, respectively. The oil was further shown to completely inhibit filamentation in C. albicans at concentrations below the respective MIC (0.08 μL/mL), with cis-β-ocimene being the main compound responsible for this inhibition (0.02 μL/mL). The flow cytometry results suggest a mechanism of action ultimately leading to cytoplasmic membrane disruption and cell death. L. multifida essential oil may be useful in complementary therapy to treat disseminated candidosis, since the inhibition of filamentation alone appears to be sufficient to treat this type of infection.

Evaluation of various glyphosate concentrations on DNA damage in human Raji cells and its impact on cytotoxicity.

PubMed

Townsend, Michelle; Peck, Connor; Meng, Wei; Heaton, Matthew; Robison, Richard; O'Neill, Kim

2017-04-01

Glyphosate is a highly used active compound in agriculturally based pesticides. The literature regarding the toxicity of glyphosate to human cells has been highly inconsistent. We studied the resulting DNA damage and cytotoxicity of various glyphosate concentrations on human cells to evaluate DNA damaging potential. Utilizing human Raji cells, DNA damage was quantified using the comet assay, while cytotoxicity was further analyzed using MTT viability assays. Several glyphosate concentrations were assessed, ranging from 15 mM to 0.1 μM. We found that glyphosate treatment is lethal to Raji cells at concentrations above 10 mM, yet has no cytotoxic effects at concentrations at or below 100 μM. Treatment concentrations of 1 mM and 5 mM induce statistically significant DNA damage to Raji cells following 30-60 min of treatment, however, cells show a slow recovery from initial damage and cell viability is unaffected after 2 h. At these same concentrations, cells treated with additional compound did not recover and maintained high levels of DNA damage. While the cytotoxicity of glyphosate appears to be minimal for physiologically relevant concentrations, the compound has a definitive cytotoxic nature in human cells at high concentrations. Our data also suggests a mammalian metabolic pathway for the degradation of glyphosate may be present. Copyright © 2017 Elsevier Inc. All rights reserved.

Action of caffeine on x-irradiated HeLa cells. V. Identity of the sector of cells that expresses potentially lethal damage in G/sub 1/ and G/sub 2/

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

Beetham, K.L.; Tolmach, L.J.

1982-07-01

When HeLa S3 cells are irradiated in early G/sub 1/ with 4 Gy of 220-kV x rays and are then incubated in growth medium containing up to 5 mM caffeine, survival is reduced (as reported previously), reaching a concentration-dependent plateau. Cell killing presumably occurs as a result of the fixation of a portion of the potentially lethal damage the cells contain. These cells respond to continued treatment with caffeine at concentrations greater than 2 mM during S, but less so than during G/sub 1/. When they reach G/sub 2/ arrest, however, extensive cell killing again occurs (reported previously), presumably alsomore » the result of potentially lethal damage fixation. G/sub 1/-irradiated cultures that are treated with caffeine either continuously at a concentration in the range 1 to 5 mM, or at 10 mM for 8 hr and subsequently with the low concentration, achieve the same survival level in G/sub 2/, provided that the potentially lethal damage is not repaired during G/sub 1/ and S. Repair seems to be completely inhibited in the presence of 3 to 4 mM caffeine. The results indicate that fixation of potentially lethal damage occurs in the same sector of cells in G/sub 1/ and G/sub 2/, suggesting that the same cellular lesion gives rise to cell killing in the two phases.« less

Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

PubMed

Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

2013-07-02

A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

Human radiation tolerance

NASA Technical Reports Server (NTRS)

Lushbaugh, C. C.

1974-01-01

The acute radiation syndrome in man is clinically bounded by death at high dose levels and by the prodromal syndrome of untoward physiological effects at minimal levels of clinically effective exposure. As in lower animals, man experiences principally three acute modes of death from radiation exposure (Bond et al., 1965). These are known collectively as the lethal radiation syndromes: central nervous system death, gastrointestinal death, and hematopoietic death. The effect of multiple exposure on lethality, the effect of multiple exposure on hematopoietic recovery, and quantitative aspects of cell and tissue repair are discussed.

In Vitro Anti-Candida Activity of Lidocaine and Nitroglycerin: Alone and Combined

PubMed Central

Palmeira-de-Oliveira, Ana; Ramos, Ana Rita; Gaspar, Carlos; Palmeira-de-Oliveira, Rita; Gouveia, Paula; Martinez-de-Oliveira, José

2012-01-01

The aim of this work was to study the anti-Candida activity of lidocaine and nitroglycerin alone and in combination. Ten Candida strains were included, corresponding to 1 collection type strain (ATCC 10231) and 9 clinical isolates: 4 C. albicans, 2 C. glabrata, 1 C. tropicalis, 1 C. krusei, and 1 C. parapsilosis. The CLSI reference M27-A3 micromethod was used to determine the anti-Candida activity of the drugs alone; minimal inhibitory and lethal concentrations were determined. The classic checkboard technique was used to determine the activity of combined drugs. Lidocaine fungicidal effect was dosedependent. Nitroglycerin exhibited a higher effect. The drugs combination resulted in a reduction of the inhibitory concentration, corresponding to an additive effect. In conclusion, both drugs exhibited an interesting anti-Candida activity. The combination of lidocaine with nitroglycerin was shown to have an additive effect against Candida spp., predicting the interest to include, in the future, these drugs in a new delivery system for the treatment of mucocutaneous candidosis. PMID:22675243

Sustained Protection against Superficial Bacterial and Fungal Infection by Topical Treatment.

DTIC Science & Technology

1974-12-31

from 1:100 to 1:1,000,000. The test organisms were a cutaneous micrococcus (Baird-Parker type 3), a diphtheroid, C. minutis- simum, Pseudomonas...all aluminum salts. Aluminum chlorhydroxide killed the micrococcus and diphtheroid out to the 1:1000 dilution. Aluminum chloride was lethal to the... micrococcus and diphtheroid only at the 1:100 concentration. Aluminum acetate was lethal only to the micrococcU . at the 1:100 concentration. COMMENT All

HSP70 expression in Biomphalaria glabrata snails exposed to cadmium.

PubMed

da Silva Cantinha, Rebeca; Borrely, Sueli Ivone; Oguiura, Nancy; de Bragança Pereira, Carlos Alberto; Rigolon, Marcela M; Nakano, Eliana

2017-06-01

In this study, the effects of the heavy metal cadmium on the stress protein HSP70 are investigated in freshwater mollusks Biomphalaria glabrata. Adult snails were exposed for 96h to CdCl 2 at concentrations ranging from 0.09 to 0.7mgL -1 (LC 50/96h =0.34 (0.30-0.37). Time and concentration-dependent increases in the expression of HSP70 were observed at sub-lethal levels in the immunoblotting assay. Further, an increased survival to a lethal heat shock was observed in animals pre-exposed to a nonlethal concentration of cadmium, evidencing the induction of acquired tolerance. The present study demonstrated the inducibility of B. glabrata HSP70 by cadmium, a relevant environmental contaminant, at non-lethal levels, providing evidences that the assessment of HSP70 in B. glabrata can be regarded as a suitable biomarker for ecotoxicological studies. Copyright © 2017 Elsevier Inc. All rights reserved.

Teratogenic and toxic effects of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum (W.Curt.:Fr.) P. Karst. (higher Basidiomycetes), on zebrafish embryo as model.

PubMed

Dulay, Rich Milton R; Kalaw, Sofronio P; Reyes, Renato G; Alfonso, Noel F; Eguchi, Fumio

2012-01-01

This paper highlights the teratogenic and toxic effects of Ganoderma lucidum (Lingzhi or Reishi mushroom) extract on zebrafish embryos. Hatchability, malformations, and lethality rate of zebrafish embryos were assessed to provide valuable information regarding the potential teratogenic activity of G. lucidum. Hatching was completed 48 h post treatment application (hpta) at 1% or lower concentrations of extract and embryo water. The hatching rate of embryos treated with 5% or higher concentrations was significantly lower (p> 0.05) than the control. Tail malformation was the most marked morphological abnormality in embryos at 72 hpta, which was obviously caused by 1% extract (55.56% tail malformation) and was observed in all embryos exposed to 5% of extract. Growth retardation was evident in embryos exposed to 5%, 10%, and 20%. However, lethal effect of extract of G. lucidum was dependent on dose and time of exposure. Mortality rates of embryos treated with 5% (44.44%) or higher concentrations of the extract was significantly higher (p > 0.05) than that of the control embryos at 72 hpta. These results suggest that G. lucidum extract has lethal and sub-lethal effects on zebrafish embryos.

Resveratrol Antagonizes Antimicrobial Lethality and Stimulates Recovery of Bacterial Mutants

PubMed Central

Liu, Yuanli; Zhou, Jinan; Qu, Yilin; Yang, Xinguang; Shi, Guojing; Wang, Xiuhong; Hong, Yuzhi; Drlica, Karl; Zhao, Xilin

2016-01-01

Reactive oxygen species (ROS; superoxide, peroxide, and hydroxyl radical) are thought to contribute to the rapid bactericidal activity of diverse antimicrobial agents. The possibility has been raised that consumption of antioxidants in food may interfere with the lethal action of antimicrobials. Whether nutritional supplements containing antioxidant activity are also likely to interfere with antimicrobial lethality is unknown. To examine this possibility, resveratrol, a popular antioxidant dietary supplement, was added to cultures of Escherichia coli and Staphylococcus aureus that were then treated with antimicrobial and assayed for bacterial survival and the recovery of mutants resistant to an unrelated antimicrobial, rifampicin. Resveratrol, at concentrations likely to be present during human consumption, caused a 2- to 3-fold reduction in killing during a 2-hr treatment with moxifloxacin or kanamycin. At higher, but still subinhibitory concentrations, resveratrol reduced antimicrobial lethality by more than 3 orders of magnitude. Resveratrol also reduced the increase in reactive oxygen species (ROS) characteristic of treatment with quinolone (oxolinic acid). These data support the general idea that the lethal activity of some antimicrobials involves ROS. Surprisingly, subinhibitory concentrations of resveratrol promoted (2- to 6-fold) the recovery of rifampicin-resistant mutants arising from the action of ciprofloxacin, kanamycin, or daptomycin. This result is consistent with resveratrol reducing ROS to sublethal levels that are still mutagenic, while the absence of resveratrol allows ROS levels to high enough to kill mutagenized cells. Suppression of antimicrobial lethality and promotion of mutant recovery by resveratrol suggests that the antioxidant may contribute to the emergence of resistance to several antimicrobials, especially if new derivatives and/or formulations of resveratrol markedly increase bioavailability. PMID:27045517

The genetic diversity of metronidazole susceptibility in Trichomonas vaginalis clinical isolates in an Egyptian population.

PubMed

Abdel-Magied, Aida A; El-Kholya, El-Said I; Abou El-Khair, Salwa M; Abdelmegeed, Eman S; Hamoudaa, Marwa M; Mohamed, Sara A; El-Tantawy, Nora Labeeb

2017-11-01

Trichomoniasis is the most common curable sexually transmitted disease worldwide. Resistance to metronidazole in treating trichomoniasis is a problematic health issue. We aimed to determine the minimum lethal concentration (MLC) of metronidazole for Trichomonas vaginalis isolates detected in Mansoura, Egypt and studied the genotypic profile of these isolates. Vaginal swab specimens were obtained from 320 symptomatic and 100 asymptomatic females, for whom clinical examination, vaginal discharge wet mount, Giemsa stain, and culture in modified Diamond's media were performed. Metronidazole susceptibility testing by an aerobic tube assay was performed. Both sensitive and resistant isolates were examined by PCR amplification followed by restriction fragment length polymorphism (RFLP). Trichomonas vaginalis was identified in 49/420 (11.7%) using either culture or PCR, while wet mount and Giemsa stain detected the parasite in 8.1 and 7.6% of participants, respectively. After 48 h incubation, most isolates were sensitive to metronidazole with a minimal lethal concentration (MLC) of 1 μg/ml. Mild resistance was observed in two isolates with MLCs of 64 μg\\ml and mild to moderate resistance was observed in an additional two isolates with MLCs of 128 μg/ml. The four isolates that demonstrated low to moderate metronidazole resistance displayed a unique genotype band pattern by RFLP compared to the other 45 samples that were metronidazole sensitive. Our results highlight the presence of in vitro metronidazole tolerance in a few T. vaginalis isolates in Mansoura, Egypt that may lead to the development of drug resistance as well as the possibility of an identifying RFLP pattern in the isolates.

Modeling response of species to microcontaminants: comparative ecotoxicology by (sub)lethal body burdens as a function of species size and partition ratio of chemicals.

PubMed

Hendriks, A J

1995-11-01

A model was designed and calibrated with accumulation data to calculate the internal concentrations of microcontaminants in organisms as a function of a few constants and variables. The main factors are the exposure time, the external exposure concentration, the partition ratio of the compound, and the size of the taxon concerned. The model was applied to calculate the lethal and sublethal body burdens of several priority compounds and some major taxa. Estimations were generally confirmed at the order of magnitude level by measured residues and applied doses if available. According to the estimations, most priority compounds chosen were critical for most taxa above internal concentrations of 0.1 mmol.kg-1 wet wt. Trichloromethane, 1,2,4-trichlorobenzene, and hexachlorobenzene were lethal above this level only, whereas other organic microcontaminants affected at least some taxa at lower body burdens. The log(Kow) of the organic compounds ranged from 2.0 to 7.0. Keeping in mind that bioconcentration and -magnification ratios for metals may be quite variable, the lowest critical residues estimated were just below the value of 0.1 mmol.kg-1 wet wt. Here, external concentrations encountered in natural habitats seem to be a promising tool for predictive comparative ecotoxicology. The critical body burdens for plants and invertebrates may have been overestimated due to uncertainty about the parameters. Among the different taxa, however, the fish families chosen (Salmonidae and Cyprinidae) seem to be most sensitive to most compounds. Internal response concentrations of the herbicide atrazine were the lowest in micro- and macrophytes, whereas parathion affected invertebrates at low levels. The database that provided the external response concentrations was also consulted to estimate so-called extrapolation or safety factors. On average, long-term no effect concentrations in water are estimated to be about 10-30 times below short-term median lethal levels. In general, short-term versus long-term, lethal versus sublethal, and median versus no response concentration ratios each contributed factors of about 2-3 to this overall ratio. The model for internal concentrations indicated that the ratio between the short-term and the long-term LC50 will be high for large species and high octanol-water partition ratios.

Lethal and sub-lethal effect of Beauveria bassiana strain NI8 on Chrysoperla rufilabris (Neuroptera:Chrysopidae)

USDA-ARS?s Scientific Manuscript database

A Mississippi Delta native strain (NI8 ARSEF8889) of Beauveria bassiana (Balsamo) Vuillemin (Sordariomycetes: Hypocrales), isolated from Lygus lineolaris (Palisot de Beauvois), was bioassayed on green lacewings, Chrysoperla rufilabris Burmeister (Neuroptera: Chrysopidae) at four spray concentrations...

Lethal exposure: An integrated approach to pathogen transmission via environmental reservoirs

PubMed Central

Turner, Wendy C.; Kausrud, Kyrre L.; Beyer, Wolfgang; Easterday, W. Ryan; Barandongo, Zoë R.; Blaschke, Elisabeth; Cloete, Claudine C.; Lazak, Judith; Van Ert, Matthew N.; Ganz, Holly H.; Turnbull, Peter C. B.; Stenseth, Nils Chr.; Getz, Wayne M.

2016-01-01

To mitigate the effects of zoonotic diseases on human and animal populations, it is critical to understand what factors alter transmission dynamics. Here we assess the risk of exposure to lethal concentrations of the anthrax bacterium, Bacillus anthracis, for grazing animals in a natural system over time through different transmission mechanisms. We follow pathogen concentrations at anthrax carcass sites and waterholes for five years and estimate infection risk as a function of grass, soil or water intake, age of carcass sites, and the exposure required for a lethal infection. Grazing, not drinking, seems the dominant transmission route, and transmission is more probable from grazing at carcass sites 1–2 years of age. Unlike most studies of virulent pathogens that are conducted under controlled conditions for extrapolation to real situations, we evaluate exposure risk under field conditions to estimate the probability of a lethal dose, showing that not all reservoirs with detectable pathogens are significant transmission pathways. PMID:27265371

Antifungal activity and chemical composition of essential oils from Smyrnium olusatrum L. (Apiaceae) from Italy and Portugal.

PubMed

Marongiu, B; Piras, A; Porcedda, S; Falconieri, D; Frau, M A; Maxia, A; Gonçalves, M J; Cavaleiro, C; Salgueiro, L

2012-01-01

The essential oils and supercritical CO₂ extracts of wild Smyrnium olusatrum L. growing in Sardinia (Italy) and in Portugal were investigated. For the study, oils were isolated from total plant aerial part (umbels containing seeds). The content of β-phellandrene (67.3% vs. 42.7%) and α-pinene (31.9% vs. 1.2%), respectively, the main components of Portuguese and Italian essential oils, declined during the maturation stage of the umbels. Contrarily, some other important components, particularly curzerene, germacrene B, germacrone, alexandrofuran, 1-β-acetoxyfurano-4(15)-eudesmene and 1-β-acetoxyfurano-3-eudesmene, increased in fruiting umbels. The chemical composition of the Sardinian oil is rather different from those of other origin. The composition of the supercritical extracts and the essential oils is markedly different, particularly due to the high amount of furanosesquiterpenoids in the supercritical fluid extraction. The minimal inhibitory concentration (MIC) and the minimal lethal concentration were used to evaluate the antifungal activity of the oils against Candida albicans, Candida tropicalis, Candida krusei, Candida guillermondii, Candida parapsilosis, Cryptococcus neoformans, Trichophyton rubrum, Trichophyton mentagrophytes, Microsporum canis, Microsporum gypseum, Epidermophyton floccosum, Aspergillus niger, Aspergillus fumigatus and Aspergillus flavus. The oils were particularly active against dermatophyte strains and C. neoformans, with MIC values in the range of 0.32-0.64 µL mL⁻¹.

Essential oil of Juniperus communis subsp. alpina (Suter) Čelak needles: chemical composition, antifungal activity and cytotoxicity.

PubMed

Cabral, C; Francisco, V; Cavaleiro, C; Gonçalves, M J; Cruz, M T; Sales, F; Batista, M T; Salgueiro, L

2012-09-01

Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria and fungi. In the present work the composition and the antifungal activity of the oils of Juniperus communis subsp. alpina (Suter) Čelak were evaluated. Moreover, the skin cytotoxicity, at concentrations showing significant antifungal activity, was also evaluated. The oils were isolated by hydrodistillation and analysed by gas chromatography and gas chromatography-mass spectrometry. Minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were used to evaluate the antifungal activity of the oil against dermatophytes (Epidermophyton floccosum, Microsporum canis, M. gypseum, Trichophyton mentagrophytes, T. mentagrophytes var. interdigitale, T. rubrum, T. verrucosum), yeasts (Candida albicans, C. guillermondii, C. krusei, C. parapsilosis, C. tropicalis, Cryptococcus neoformans) and Aspergillus species (Aspergillus flavus, A. fumigatus, A. niger). Cytotoxicity was tested in HaCaT keratinocytes through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Essential oil of J. communis subsp. alpina needles was predominantly composed of monoterpene hydrocarbons (78.4%), with the main compounds being sabinene (26.2%), α-pinene (12-9%) and limonene (10.4%). Results concerning the antifungal activity demonstrated the potential of needle oil against dermatophytes, particularly for Microsporum canis and Trichophyton rubrum with MIC and MLC of 0.32 μL/mL. Furthermore, evaluation of cell viability showed no significant cytotoxicity in HaCaT keratinocytes at concentrations between 0.32 and 0.64 μL/mL. These results show that it is possible to find appropriate doses of J. communis subsp. alpina oil with both antifungal activity and a very low detrimental effect on keratinocytes. Copyright © 2012 John Wiley & Sons, Ltd.

Ethylhexylglycerin Impairs Membrane Integrity and Enhances the Lethal Effect of Phenoxyethanol

PubMed Central

Langsrud, Solveig; Steinhauer, Katrin; Lüthje, Sonja; Weber, Klaus; Goroncy-Bermes, Peter; Holck, Askild L.

2016-01-01

Preservatives are added to cosmetics to protect the consumers from infections and prevent product spoilage. The concentration of preservatives should be kept as low as possible and this can be achieved by adding potentiating agents. The aim of the study was to investigate the mechanisms behind potentiation of the bactericidal effect of a commonly used preservative, 2-phenoxyethanol (PE), by the potentiating agent ethylhexylglycerin (EHG). Sub-lethal concentrations of EHG (0.075%) and PE (0.675%) in combination led to rapid killing of E. coli (> 5 log reduction of cfu after 30 min), leakage of cellular constituents, disruption of the energy metabolism, morphological deformities of cells and condensation of DNA. Used alone, EHG disrupted the membrane integrity even at low concentrations. In conclusion, sub-lethal concentrations of EHG potentiate the effect of PE through damage of the cell membrane integrity. Thus, adding EHG to PE in a 1:9 ratio has a similar effect on membrane damage and bacterial viability as doubling the concentration of PE. This study provides insight about the mechanism of action of a strong potentiating agent, EHG, which is commonly used in cosmetics together with PE. PMID:27783695

Younger rats are more susceptible to the lethal effects of sarin than adult rats: 24 h LC50 for whole-body (10 and 60 min) exposures.

PubMed

Wright, Linnzi K M; Lumley, Lucille A; Lee, Robyn B; Taylor, James T; Miller, Dennis B; Muse, William T; Emm, Edward J; Whalley, Christopher E

2017-04-01

Chemical warfare nerve agents (CWNA) inhibit acetylcholinesterase and are among the most lethal chemicals known to man. Children are predicted to be vulnerable to CWNA exposure because of their smaller body masses, higher ventilation rates and immature central nervous systems. While a handful of studies on the effects of CWNA in younger animals have been published, exposure routes relevant to battlefield or terrorist situations (i.e. inhalation for sarin) were not used. Thus, we estimated the 24 h LC 50 for whole-body (10 and 60 min) exposure to sarin using a stagewise, adaptive dose design. Specifically, male and female Sprague-Dawley rats were exposed to a range of sarin concentrations (6.2-44.0 or 1.6-12.5 mg/m³) for either 10 or 60 min, respectively, at six different times during their development (postnatal day [PND] 7, 14, 21, 28, 42 and 70). For male and female rats, the lowest LC 50 values were observed for PND 14 and the highest LC 50 values for PND 28. Sex differences were observed only for PND 42 for the 10 min exposures and PND 21 and 70 for the 60 min exposures. Thus, younger rats (PND 14) were more susceptible than older rats (PND 70) to the lethal effects of whole-body exposure to sarin, while adolescent (PND 28) rats were the least susceptible and sex differences were minimal. These results underscore the importance of controlling for the age of the animal in research on the toxic effects associated with CWNA exposure.

Active avoidance from a crude oil soluble fraction by an Andean paramo copepod.

PubMed

Araújo, Cristiano V M; Moreira-Santos, Matilde; Sousa, José P; Ochoa-Herrera, Valeria; Encalada, Andrea C; Ribeiro, Rui

2014-09-01

Several oil spills due to ruptures in the pipeline oil systems have occurred at the Andean paramo. A sample of this crude oil was mixed with water from a nearby Andean lagoon and the toxicity of the soluble fraction was assessed through lethal and avoidance assays with a locally occurring copepod (Boeckella occidentalis intermedia). The integration of mortality and avoidance aimed at predicting the immediate decline of copepod populations facing an oil leakage. The 24-h median lethal PAH concentration was 42.7 (26.4-91.6) µg L(-1). In the 12-h avoidance assay, 30% avoidance was recorded at the highest PAH concentration (19.4 µg L(-1)). The mortality at this PAH concentration would be of 25% and, thus, the population immediate decline would be of 55%. The inclusion of non-forced exposure testing with the quantification of the avoidance response in environmental risk assessments is, therefore, supported due to underestimation of the lethal assays.

Polychlorinated biphenyl toxicity to Japanese quail as related to degree of chlorination

USGS Publications Warehouse

Hill, E.F.; Heath, R.G.; Spann, J.W.; Williams, J.D.

1974-01-01

To learn if the percentage of chlorine in a mixture of polychlorinated biphenyls (PCB's) alone determines toxicity, Japanese quail were fed diets containing Aroelor 1248, 1254, or 1260 at levels that added equal amounts of chlorine to the feed. The experiment comprised two consecutive 5-day periods; three sublethal concentrations of chlorine were evaluated during the first period and three lethal concentrations during the second period. Evaluations utilized comparisons of mortality, time to death, weight change, and food consumption. Sublethal concentrations produced no detectable effects. Lethal concentrations with equal Chlorine showed Aroelor 1248 to be less toxic at the highest chlorine concentrations, but at lower concentrations Aroelor 1254 was more toxic than Aroclor 1260. Although chlorine percentage of a PCB is positively correlated with its avian toxicity, PCB toxicity is apparently not simply a function of chlorination.

The in vitro impact of toothpaste extracts on cell viability.

PubMed

Cvikl, Barbara; Lussi, Adrian; Gruber, Reinhard

2015-06-01

Toothpastes contain three main components: detergents, abrasives, and fluoride. Detergents, particularly sodium lauryl sulfate, have been proposed as components that enable toothpastes to produce cytotoxic effects in vitro. However, not all toothpastes contain sodium lauryl sulfate, and almost no studies have found an association between detergents and the in vitro cytotoxicity of toothpastes. The present study examined the in vitro cytotoxicity of nine commercially available toothpastes containing four different detergents. Toothpastes were diluted in serum-free medium, centrifuged, and filter sterilized. The half-lethal concentration of the toothpaste-conditioned medium (TCM) was calculated based on the formation of formazan by gingival fibroblasts, oral squamous cell carcinoma HSC-2 cells, and L929 cells. Cell proliferation was analyzed, and live-dead staining was performed, after exposure of cells to conditioned medium prepared with 1% toothpaste (1% TCM). It was found that toothpastes containing sodium lauryl sulfate and amine fluoride strongly inhibited cell viability with the half-lethal concentration being obtained with conditioned medium prepared with approximately 1% toothpaste (1% TCM). Toothpastes containing cocamidopropyl betaine and Steareth-20 showed higher half-lethal concentration values, with the half-lethal concentration being obtained with conditioned medium prepared with 10% (10% TCM) and 70% (70% TCM) toothpaste, respectively. Proliferation and live-dead data were consistent with the cell-viability analyses. These results demonstrate that the type of detergent in toothpastes can be associated with changes in in vitro cell toxicity. © 2015 Eur J Oral Sci.

Sub-lethal effects of the neurotoxic pyrethroid insecticide Fastac 50EC on the general motor and locomotor activities of the non-targeted beneficial carabid beetle Platynus assimilis (Coleoptera: Carabidae).

PubMed

Tooming, Ene; Merivee, Enno; Must, Anne; Sibul, Ivar; Williams, Ingrid

2014-06-01

Sub-lethal effects of pesticides on behavioural endpoints are poorly studied in carabids (Coleoptera: Carabidae) though changes in behaviour caused by chemical stress may affect populations of these non-targeted beneficial insects. General motor activity and locomotion are inherent in many behavioural patterns, and changes in these activities that result from xenobiotic influence mirror an integrated response of the insect to pesticides. Influence of pyrethroid insecticides over a wide range of sub-lethal doses on the motor activities of carabids still remains unclear. Video tracking of Platynus assimilis showed that brief exposure to alpha-cypermethrin at sub-lethal concentrations ranged from 0.01 to 100 mg L(-1) caused initial short-term (< 2 h) locomotor hyperactivity followed by a long-term (>24 h) locomotor hypo-activity. In addition, significant short- and long-term concentration and time-dependent changes occurred in general motor activity patterns and rates. Conspicuous changes in motor activity of Platynus assimilis beetles treated at alpha-cypermethrin concentrations up to 75,000-fold lower than maximum field recommended concentration (MFRC) suggest that many, basic fitness-related behaviours might be severely injured as well. These changes may negatively affect carabid populations in agro-ecosystems. Long-term hypo-activity could directly contribute to decreased trap captures of carabids frequently observed after insecticide application in the field. © 2013 Society of Chemical Industry.

Lethal and sub-lethal effects on the Asian common toad Duttaphrynus melanostictus from exposure to hexavalent chromium.

PubMed

Fernando, Vindhya A K; Weerasena, Jagathpriya; Lakraj, G Pemantha; Perera, Inoka C; Dangalle, Chandima D; Handunnetti, Shiroma; Premawansa, Sunil; Wijesinghe, Mayuri R

2016-08-01

Chromium discharged in industrial effluents frequently occurs as an environmental pollutant, but the lethal and sub-lethal effects the heavy metal might cause in animals exposed to it have been insufficiently investigated. Selecting the amphibian Duttaphrynus melanostictus, we carried out laboratory tests to investigate the effects of short and long term exposure to hexavalent chromium (Cr(VI)) in both tadpoles and adult toads. The concentrations used were 0.002, 0.02, 0.2, 1.0 and 2.0mg/L, the first three corresponding to field levels. In vitro exposures were also carried out using toad erythrocytes and Cr(VI) concentrations of 0.0015, 0.003, 0.015, 0.03, 0.15mg/L. Mortality, growth retardation, developmental delays and structural aberrations were noted in the metal-treated tadpoles, with increasing incidence corresponding to increase in Cr(VI) level and duration of exposure. Many of the sub-lethal effects were evident with long term exposure to environmentally relevant levels of the toxicant. Changes in selected blood parameters and erythrocyte morphometry were also detected in Cr(VI) exposed toads, indicating anaemic and leucopenic conditions. In the genotoxicity study, DNA damage indicated by comet assay and increased micronuclei frequency, occurred at the low Cr(VI) concentrations tested. The multiple deleterious effects of exposure to chromium signal the need for monitoring and controlling the discharge of chromium to the environment. The dose-dependency and genotoxic effects observed in this widely distributed Asian toad indicates its suitability for monitoring heavy metal pollution in aquatic systems. Copyright © 2016 Elsevier B.V. All rights reserved.

[Injuries and fatalities caused by gas-/warning weapons].

PubMed

Maxeiner, H; Schneider, V

1989-01-01

Detailed report of 5 cases of violation with gas or warning firearms, 3 of them lethal. In one case a modified weapon (elongated barrel) and steel bullets were used, resulting in shot of the head with retained missile and lethal bleeding. In the other cases, regular weapons (8 or 9 mm cartridges) were used for contact shots; violation occurred only by the effect of powder gases. One of these cases was a suizide (lethal temporal gunshot), in the other cases shots by another person: a) shot against the arm with large soft-tissue damage (survived); b) and c) shot against the neck with exceeding rupture of the soft tissues, minimal damage of the neck arteries and in one cases bilateral tears of the hypopharynx. In this case a delayed death after primarily well operated injury occurred after 12 days by bleeding into the airways from ruptured external carotid artery.

DETERMINATION OF LETHAL DISSOLVED OXYGEN LEVELS FOR SELECTED MARINE AND ESTUARINE FISHES, CRUSTACEANS AND A BIVALVE

EPA Science Inventory

The objective of this study was to provide a database of the incipient lethal concentrations for reduced dissolved oxygen (DO) for selected marine and estuarine species including 12 species of fish, 9 crustaceans, and 1 bivalve. All species occur in the Virginian Province, USA, w...

How low can you go? Assessing minimum concentrations of NSC in carbon limited tree saplings

NASA Astrophysics Data System (ADS)

Hoch, Guenter; Hartmann, Henrik; Schwendener, Andrea

2016-04-01

Tissue concentrations of non-structural carbohydrates (NSC) are frequently used to determine the carbon balance of plants. Over the last years, an increasing number of studies have inferred carbon starvation in trees under environmental stress like drought from low tissue NSC concentrations. However, such inferences are limited by the fact that minimum concentrations of NSC required for survival are not known. So far, it was hypothesized that even under lethal carbon starvation, starch and low molecular sugar concentrations cannot be completely depleted and that minimum NSC concentrations at death vary across tissues and species. Here we present results of an experiment that aimed to determine minimum NSC concentrations in different tissues of saplings of two broad-leaved tree species (Acer pseudoplatanus and Quercus petratea) exposed to lethal carbon starvation via continuous darkening. In addition, we investigated recovery rates of NSC concentrations in saplings that had been darkened for different periods of time and were then re-exposed to light. Both species survived continuous darkening for about 12 weeks (confirmed by testing the ability to re-sprout after darkness). In all investigated tissues, starch concentrations declined close to zero within three to six weeks of darkness. Low molecular sugars also decreased strongly within the first weeks of darkness, but seemed to stabilize at low concentrations of 0.5 to 2 % dry matter (depending on tissue and species) almost until death. NSC concentrations recovered surprisingly fast in saplings that were re-exposed to light. After 3 weeks of continuous darkness, tissue NSC concentrations recovered within 6 weeks to levels of unshaded control saplings in all tissues and in both species. To our knowledge, this study represents the first experimental attempt to quantify minimum tissue NSC concentrations at lethal carbon starvation. Most importantly, our results suggest that carbon-starved tree saplings are able to survive several weeks without starch reserves and with extremely low sugar concentrations in all organs. Although it remains to be tested whether our findings are also valid for mature trees, these results show that NSC pools in trees are very sensitive to carbon limitation and that lethal carbon starvation is preceded by a significant (almost complete) depletion of starch and sugars in all tree organs.

De Novo Emergence of Genetically Resistant Mutants of Mycobacterium tuberculosis from the Persistence Phase Cells Formed against Antituberculosis Drugs In Vitro

PubMed Central

Sebastian, Jees; Swaminath, Sharmada; Nair, Rashmi Ravindran; Jakkala, Kishor; Pradhan, Atul

2016-01-01

ABSTRACT Bacterial persisters are a subpopulation of cells that can tolerate lethal concentrations of antibiotics. However, the possibility of the emergence of genetically resistant mutants from antibiotic persister cell populations, upon continued exposure to lethal concentrations of antibiotics, remained unexplored. In the present study, we found that Mycobacterium tuberculosis cells exposed continuously to lethal concentrations of rifampin (RIF) or moxifloxacin (MXF) for prolonged durations showed killing, RIF/MXF persistence, and regrowth phases. RIF-resistant or MXF-resistant mutants carrying clinically relevant mutations in the rpoB or gyrA gene, respectively, were found to emerge at high frequency from the RIF persistence phase population. A Luria-Delbruck fluctuation experiment using RIF-exposed M. tuberculosis cells showed that the rpoB mutants were not preexistent in the population but were formed de novo from the RIF persistence phase population. The RIF persistence phase M. tuberculosis cells carried elevated levels of hydroxyl radical that inflicted extensive genome-wide mutations, generating RIF-resistant mutants. Consistent with the elevated levels of hydroxyl radical-mediated genome-wide random mutagenesis, MXF-resistant M. tuberculosis gyrA de novo mutants could be selected from the RIF persistence phase cells. Thus, unlike previous studies, which showed emergence of genetically resistant mutants upon exposure of bacteria for short durations to sublethal concentrations of antibiotics, our study demonstrates that continuous prolonged exposure of M. tuberculosis cells to lethal concentrations of an antibiotic generates antibiotic persistence phase cells that form a reservoir for the generation of genetically resistant mutants to the same antibiotic or another antibiotic. These findings may have clinical significance in the emergence of drug-resistant tubercle bacilli. PMID:27895008

Optofluidic technology for monitoring rotifer Brachionus calyciflorus responses to regular light pulses

NASA Astrophysics Data System (ADS)

Cartlidge, Rhys; Campana, Olivia; Nugegoda, Dayanthi; Wlodkowic, Donald

2016-12-01

Behavioural alterations can occur as a result of a toxicant exposure at concentrations significantly lower than lethal effects that are commonly measured in acute toxicity testing. The use of alternating light and dark photoperiods to test phototactic responses of aquatic invertebrates in the presence of environmental contaminants provides an attractive analytical avenue. Quantification of phototactic responses represents a sublethal endpoint that can be employed as an early warning signal. Despite the benefits associated with the assessment of these endpoints, there is currently a lack of automated and miniaturized bioanalytical technologies to implement the development of toxicity testing with small aquatic species. In this study we present a proof-of-concept microfluidic Lab-on-a-Chip (LOC) platform for the assessment of rotifer swimming behavior in the presence of the toxicant copper sulfate. The device was designed to assess impact of toxicants at sub-lethal concentrations on freshwater crustacean Brachionus calyciflorus, testing behavioral endpoints such as animal swimming distance, speed and acceleration. The LOC device presented in this work enabled straightforward caging of microscopic crustaceans as well as non-invasive analysis of rapidly swimming animals in a focal plane of a video-microscopy system. The chip-based technology was fabricated using a new photolithography method that enabled formation of thick photoresist layers with minimal distortion. Photoresist molds were then employed for replica molding of LOC devices with poly(dimethylsiloxane) (PDMS) elastomer. The complete bioanalytical system consisted of: (i) microfluidic PDMS chip-based device; (ii) peristaltic microperfusion pumping manifold; (iii) miniaturized CMOS camera for video data acquisition; and (iv) video analysis software algorithms for quantification of changes in swimming behaviour of B. calyciflorus in response to reference toxicants.

Effective degradation of methylisothiazolone biocide using ozone: Kinetics, mechanisms, and decreases in toxicity.

PubMed

Li, Ang; Wu, Qian-Yuan; Tian, Gui-Peng; Hu, Hong-Ying

2016-12-01

Methylisothiazolone (MIT) is a common biocide that is widely used in water-desalination reverse-osmosis processes. The transformation of MIT during water treatment processes is poorly understood. The kinetics and mechanisms involved in the degradation of MIT during ozonation were investigated in this study. Ozonation was found to be a useful way of degrading MIT in water, and the degradation rate constant was 0.11 (±0.1) × 10 3  L/(mol·s). The degradation rate constant did not change when the pH was increased from 3 to 9. The pre-exponential factor A and the activation energy E a for the ozonation process were 7.564 × 10 13  L/(mol·s) and 66.74 kJ/mol, respectively. The decrease in the MIT concentration and the amount of ozone consumed were measured, and the stoichiometric factor α for the ozone consumption to MIT removal ratio was found to be 1.8. Several ozonation products were detected using time-of-flight mass spectrometry. Almost 32% of the organic sulfur in the MIT was oxidized to release sulfate ions, which caused a decrease in pH. Sulfur atoms were oxidized to sulfone species and then hydrolyzed to give sulfate during ozonation. Addition reactions involving carbon-carbon double bonds and the oxidation of α-carbon atoms also occurred. MIT was found to be lethal to Daphnia magna Straus (D. magna) with a median lethal concentration of 18.2 μmol/L. Even though the primary ozonation products of MIT still showed some toxicity to D. magna, ozone could minimize the toxic effect after a long reaction time. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lethal and sub-lethal evaluation of Indigo Carmine dye and byproducts after TiO2 photocatalysis in the immune system of Eisenia andrei earthworms.

PubMed

Genázio Pereira, Patrícia Christina; Reimão, Roberta Valoura; Pavesi, Thelma; Saggioro, Enrico Mendes; Moreira, Josino Costa; Veríssimo Correia, Fábio

2017-09-01

The Indigo carmine (IC) dye has been widely used in textile industries, even though it has been considered toxic for rats, pigs and humans. Owing to its toxicity, wastes containing this compound should be treated to minimize or eliminate their toxic effects on the biota. As an alternative to wastewater treatment, advanced oxidative processes (AOPs) have been highlighted due to their high capacity to destruct organic molecules. In this context, this study aimed to evaluate Indigo Carmine toxicity to soil organisms using the earthworm Eisenia andrei as a model-organism and also verify the efficiency of AOP in reducing its toxicity to these organisms. To this end, lethal (mortality) and sub-lethal (loss or gain of biomass, reproduction, behavior, morphological changes and immune system cells) effects caused by this substance and its degradation products in these annelids were evaluated. Morphological changes were observed even in organisms exposed to low concentrations, while mortality was the major effect observed in individuals exposed to high levels of indigo carmine dye. The organisms exposed to the IC during the contact test showed mortality after 72h of exposure (LC 50 = 75.79mgcm - 2 ), while those exposed to photoproducts showed mortality after 48h (LC 50 = 243min). In the chronic study, the organisms displayed a mortality rate of 14%, while those exposed to the photoproduct reached up to 32.7%. A negative influence of the dye on the reproduction rate was observed, while by-products affected juvenile survival. A loss of viability and alterations in the cellular proportion was verified during the chronic test. However, the compounds did not alter the behavior of the annelids in the leak test (RL ranged from 20% to 30%). Although photocatalysis has been presented as an alternative technology for the treatment of waste containing the indigo carmine dye, this process produced byproducts even more toxic than the original compounds to E. andrei. Copyright © 2017 Elsevier Inc. All rights reserved.

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...

78 FR 36671 - Acetamiprid; Pesticide Tolerances

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-19

... one of the following methods: Federal eRulemaking Portal: http://www.regulations.gov . Follow the... validity, completeness, and reliability as well as the relationship of the results of the studies to human... toxic in acute lethality studies via the oral route of exposure and is minimally toxic via the dermal...

Comprehensive analysis of venom from the scorpion Centruroides tecomanus reveals compounds with antimicrobial, cytotoxic, and insecticidal activities.

PubMed

Valdez-Velazquéz, L L; Romero-Gutierrez, M T; Delgado-Enciso, I; Dobrovinskaya, O; Melnikov, V; Quintero-Hernández, V; Ceballos-Magaña, S G; Gaitan-Hinojosa, M A; Coronas, F I; Puebla-Perez, A M; Zamudio, F; De la Cruz-García, I; Vázquez-Vuelvas, O F; Soriano-Hernandez, A D; Possani, L D

2016-08-01

Centruroides tecomanus is a medically important scorpion of the state of Colima (Mexico). This communication reports the identification of venom components of this scorpion with biological activity over insects/crickets (Acheta domestica), crustaceans/fresh water shrimps (Cambarellus montezumae), and mammalians/mice (Mus musculus, strain CD1). It also describes the pharmacological effects on cell lines in culture (L5178Y cells, HeLa cells, HuTu cells and Jurkat E6-1 cells), as well as on several types of bacteria (see below). The soluble venom of this scorpion was fractionated by high-performance liquid chromatography (HPLC) and collected separately in twelve independent fractions collected over 60 min run (5 min time apart each other). The HPLC components of fraction VII were lethal to all three species used for assay. The IVth fraction had a toxic effect on freshwater shrimps. In this species, fractions VI, VII and VIII were all lethal. For crickets, fractions V and VI were toxic and fraction VII was lethal. In mouse, the lethal components were found in fraction VII, whereas fraction VIII was toxic, but not lethal, at the doses assayed. The molecular weight of peptides from the various group of fractions were identified by mass spectrometry determination. Components lethal to mice showed molecular weights from 7013 to 7487 Da. Two peptides were obtained in homogeneous form and shown to be lethal to the three species of animal used for assay. The soluble venom tested on L5178Y cell line survival was shown to be cytotoxic, at 10-100 μg/mL concentration, when compared to control murine splenocytes (p = 0.007). The soluble venom applied to Hela, Hutu and Jurkat cell lines did not show cytotoxic effects at these concentrations. On the contrary, it seems to have a proliferative effect. However the HPLC fractions I, III, VI and XII do have a cytotoxic effect on Jurkat E06-1 cells in culture at 200 μg/mL concentration. The antimicrobial activity of the venom fractions on Staphylococcus aureus (gram-positive), Escherichia coli, Pseudomonas aeruginosa y Salmonella spp (gram-negative) was measured, using the liquid inhibition growth system. The four strains of bacteria used were susceptible to fractions III and IV, affecting all four bacterial strains at concentrations below 5 μg/mL. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lethal and behavioral impacts of diesel and fuel oil on the Antarctic amphipod Paramoera walkeri.

PubMed

Brown, Kathryn E; King, Catherine K; Harrison, Peter L

2017-09-01

Toxicity testing with Antarctic species is required for risk assessment of fuel spills in Antarctic coastal waters. The lethal and sublethal (movement behavior) sensitivities of adults and juveniles of the Antarctic amphipod Paramoera walkeri to the water accommodated fractions (WAFs) of 3 fuels were estimated in extended-duration tests at -1 °C to 21 d. Response of P. walkeri for lethal hydrocarbon concentrations was slow, with 50% lethal concentrations (LC50s) first able to be estimated at 7 d for adults exposed to Special Antarctic Blend diesel (SAB), which had the highest hydrocarbon concentrations of the 3 fuel WAFs. Juveniles showed greater response to marine gas oil (MGO) and intermediate residual fuel oil (IFO 180) at longer exposure durations and were most sensitive at 21 d to IFO 180 (LC50 = 12 μg/L). Adults were initially more sensitive than juveniles; at 21 d, however, juveniles were more than twice as sensitive as adults to SAB (LC50 = 153 μg/L and 377 μg/L, respectively). Significant effects on movement behavior were evident at earlier time points and lower concentrations than was mortality in all 3 fuel WAFs, and juveniles were highly sensitive to sublethal effects of MGO. These first estimates of Antarctic amphipod sensitivity to diesel and fuel oils in seawater contribute to the development of ecologically relevant risk assessments for management of hydrocarbon contamination in the region. Environ Toxicol Chem 2017;36:2444-2455. © 2017 SETAC. © 2017 SETAC.

Micropollutants in closed life-support systems: the case of triclosan, a biocide excreted via urine

NASA Astrophysics Data System (ADS)

Mastroleo, Felice; Pycke, Benny; Boon, Nico; de Wever, Heleen; Hendrickx, Larissa; Mastroleo, Felice; Wattiez, Ruddy; Mergeay, Max; Verstraete, Willy

OBJECTIVES: The impact of triclosan on the growth and physiology of the bacterium Rhodospirillum rubrum was studied in the frame of the regenerative life-support system, Micro- Ecological Life Support System Alternative (MELiSSA). A wide range of compounds, such as steroid hormones, pharmaceuticals and personal care products, might enter the life support system via the excrements that are to be treated and recycled. Triclosan was chosen as the first compound to be tested because MELiSSA is a closed system, which is consequently particularly sensitive to compounds inhibiting the microbial metabolism. Because triclosan is increasingly used as an antimicrobial biocide in hygienic formulations (such as toothpaste, mouthwash, deodorants, etc.) and due to its chemical stability, it is considered an emerging pollutant in terrestrial ecosystems. METHODS: In a first phase, the triclosan concentration expected in the life-support system was estimated, the Minimal Inhibitory Concentration (MIC) was determined via plating, and the effect on growth kinetics was assessed by comparing growth parameters in the Gompertz model. In a second phase, the secondary effects of triclosan on cell physiology and gene expression were studied through flow-cytometry and microarray analyses, respectively. RESULTS: Based on the pharmacokinetic data from literature, the predicted concentration range is estimated to be 6-25µg/L triclosan in the Rhodospirillum rubrum compartment of the MELiSSA. The minimal inhibitory concentration of triclosan was determined to be 71 µg/L after 7 days of exposure on Sistrom medium. Upon exposure to 50-200µg/L triclosan, triclosan-resistant mutants of Rhodospirillum rubrum arose spontaneously at high frequency (3.1 ∗ 10 - 4). Analysis of the growth kinetics of the wild-type revealed that triclosan causes an important elongation of the lag-phase and a decrease in growth rate. At concentrations higher than 75mg/L(LD = 500mg/L), triclosan is bactericidal to wild-type cells, which coincides with increased membrane permeability. Yet, triclosan depolarises the bacterial membrane by significantly reducing the membrane potential prior to being lethal. Therefore, the lysis of wild-type cells appears not to be directly associated with membrane depolarisation and is probably the result of a disturbance in the cellular envelope by triclosan. CONCLUSIONS: The triclosan concentrations expected in the MELiSSA are within the 'Predicted No Effect Concentration' range. In addition, the effect of triclosan on growth rate is minimal; even at sub-inhibitory effect concentrations, where triclosan is mainly influencing the lag-phase instead of the growth rate. Efficient reactor operation will therefore remain unchanged with slight modification of the operating parameters. However, since there are no clear indication that triclosan might be degraded in the system, except for the nitrifying compartment, triclosan might accumulate in the loop. Therefore, a thorough study of the effect of triclosan on the other compartments in the MELiSSA loop is desired, as well as potential countermeasures. Keywords: triclosan, Rhodospirillum rubrum, MELiSSA, microarray analysis, flow cytometry, chlorinated biphenylether, minimal inhibitory concentration.

Susceptibility of Blastomyces dermatitidis strains to products of oxidative metabolism.

PubMed

Sugar, A M; Chahal, R S; Brummer, E; Stevens, D A

1983-09-01

Three strains of Blastomyces dermatitidis which differ in their virulence for mice were exposed in their yeast form to various components of the peroxidase-hydrogen peroxide-halide system. Susceptibility to H2O2 alone correlated with virulence, with the most virulent strain (ATCC 26199) least susceptible (50% lethal dose, greater than 50 mM) and an avirulent strain (ATCC 26197) most susceptible (50% lethal dose less than 3.3 mM). A strain of intermediate virulence (ATCC 26198) was of intermediate susceptibility (50% lethal dose, 11.5 mM). The addition of a nontoxic concentration of KI (5 X 10(-4) M) did not increase H2O2 toxicity. However, the addition of either myeloperoxidase or horseradish peroxidase and KI markedly decreased the amount of H2O2 required to kill the organisms, with 100 +/- 0% of all strains killed at 5 X 10(-5) M H2O2 and 97 +/- 4, 100 +/- 0, and 94 +/- 8% of ATCC 26199, ATCC 26198, and ATCC 26197 killed, respectively, at 5 X 10(-6) M H2O2. Kinetic studies with H2O2 alone revealed a delayed onset of killing, but virtually 100% of organisms were killed by 120 min of exposure in all strains. By comparison, the peroxidase-hydrogen peroxide-halide system was 100% lethal for all strains at 1 min. The relatively high concentrations of H2O2 required to kill the yeast phase of B. dermatitidis suggest that H2O2 alone does not account for host resistance to the organism. However, the rapidly lethal effect of the peroxidase-hydrogen peroxide-halide system at physiologically relevant concentrations suggests that this may be one mechanism of host defense to B. dermatitidis.

Identification of lethal cluster of genes in the yeast transcription network

NASA Astrophysics Data System (ADS)

Rho, K.; Jeong, H.; Kahng, B.

2006-05-01

Identification of essential or lethal genes would be one of the ultimate goals in drug designs. Here we introduce an in silico method to select the cluster with a high population of lethal genes, called lethal cluster, through microarray assay. We construct a gene transcription network based on the microarray expression level. Links are added one by one in the descending order of the Pearson correlation coefficients between two genes. As the link density p increases, two meaningful link densities pm and ps are observed. At pm, which is smaller than the percolation threshold, the number of disconnected clusters is maximum, and the lethal genes are highly concentrated in a certain cluster that needs to be identified. Thus the deletion of all genes in that cluster could efficiently lead to a lethal inviable mutant. This lethal cluster can be identified by an in silico method. As p increases further beyond the percolation threshold, the power law behavior in the degree distribution of a giant cluster appears at ps. We measure the degree of each gene at ps. With the information pertaining to the degrees of each gene at ps, we return to the point pm and calculate the mean degree of genes of each cluster. We find that the lethal cluster has the largest mean degree.

Antibiotic development challenges: the various mechanisms of action of antimicrobial peptides and of bacterial resistance

PubMed Central

Guilhelmelli, Fernanda; Vilela, Nathália; Albuquerque, Patrícia; Derengowski, Lorena da S.; Silva-Pereira, Ildinete; Kyaw, Cynthia M.

2013-01-01

Antimicrobial peptides (AMPs) are natural antibiotics produced by various organisms such as mammals, arthropods, plants, and bacteria. In addition to antimicrobial activity, AMPs can induce chemokine production, accelerate angiogenesis, and wound healing and modulate apoptosis in multicellular organisms. Originally, their antimicrobial mechanism of action was thought to consist solely of an increase in pathogen cell membrane permeability, but it has already been shown that several AMPs do not modulate membrane permeability in the minimal lethal concentration. Instead, they exert their effects by inhibiting processes such as protein and cell wall synthesis, as well as enzyme activity, among others. Although resistance to these molecules is uncommon several pathogens developed different strategies to overcome AMPs killing such as surface modification, expression of efflux pumps, and secretion of proteases among others. This review describes the various mechanisms of action of AMPs and how pathogens evolve resistance to them. PMID:24367355

Effects of polystyrene microbeads in marine planktonic crustaceans.

PubMed

Gambardella, Chiara; Morgana, Silvia; Ferrando, Sara; Bramini, Mattia; Piazza, Veronica; Costa, Elisa; Garaventa, Francesca; Faimali, Marco

2017-11-01

Plastic debris accumulates in the marine environment, fragmenting into microplastics (MP), causing concern about their potential toxic effects when ingested by marine organisms. The aim of this study was to verify whether 0.1µm polystyrene beads are likely to trigger lethal and sub-lethal responses in marine planktonic crustaceans. MP build-up, mortality, swimming speed alteration and enzyme activity (cholinesterases, catalase) were investigated in the larval stages of Amphibalanus amphitrite barnacle and of Artemia franciscana brine shrimp exposed to a wide range of MP concentrations (from 0.001 to 10mgL -1 ) for 24 and 48h. The results show that MP were accumulated in crustaceans, without affecting mortality. Swimming activity was significantly altered in crustaceans exposed to high MP concentrations (> 1mgL -1 ) after 48h. Enzyme activities were significantly affected in all organisms exposed to all the above MP concentrations, indicating that neurotoxic effects and oxidative stress were induced after MP treatment. These findings provide new insight into sub-lethal MP effects on marine crustaceans. Copyright © 2017 Elsevier Inc. All rights reserved.

Acute oral toxicity and brine shrimp lethality of Elaeis guineensis Jacq., (oil palm leaf) methanol extract.

PubMed

Syahmi, Abdul Rani Muhamad; Vijayarathna, Soundararajan; Sasidharan, Sreenivasan; Latha, Lachimanan Yoga; Kwan, Yuet Ping; Lau, Yee Ling; Shin, Lai Ngit; Chen, Yeng

2010-11-10

Elaeis guineensis (Arecaceae) is widely used in West African traditional medicine for treating various ailments. An evaluation on the toxicity of extracts of this plant is crucial to support the therapeutic claims. The acute oral toxicity and brine shrimp lethality of a methanolic extract of this plant was tested. Oral administration of crude extract at the highest dose of 5,000 mg/kg resulted in no mortalities or evidence of adverse effects, implying that E. guineensis is nontoxic. Normal behavioral pattern, clinical signs and histology of vital organs confirm this evidence. The E. guineensis extracts screened for toxicity against brine shrimp had 50% lethal concentration (LC₅₀) values of more than 1.0 mg/mL (9.00 and 3.87 mg/mL, at 6 and 24 h, respectively), confirming that the extract was not toxic. Maximum mortalities occurred at 100 mg/mL concentration while the least mortalities happened to be at 0.195 mg/mL concentration. The results of both tests confirm that E. guineensis is nontoxic and hence safe for commercial utilization.

Acute and chronic toxicity of the new explosive CL-20 to the earthworm (Eisenia andrei) exposed to amended natural soils.

PubMed

Robidoux, Pierre Yves; Sunahara, Geoffrey I; Savard, Kathleen; Berthelot, Yann; Dodard, Sabine; Martel, Majorie; Gong, Ping; Hawari, Jalal

2004-04-01

Monocyclic nitramine explosives such as 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) are toxic to a number of ecological receptors, including earthworms. The polycyclic nitramine CL-20 (2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane) is a powerful explosive that may replace RDX and HMX, but its toxicity is not known. In the present study, the lethal and sublethal toxicities of CL-20 to the earthworm (Eisenia andrei) are evaluated. Two natural soils, a natural sandy forest soil (designated RacFor2002) taken in the Montreal area (QC, Canada; 20% organic carbon, pH 7.2) and a Sassafras sandy loam soil (SSL) taken on the property of U.S. Army Aberdeen Proving Ground (Edgewood, MD, USA; 0.33% organic carbon, pH 5.1), were used. Results showed that CL-20 was not lethal at concentrations of 125 mg/kg or less in the RacFor2002 soil but was lethal at concentrations of 90.7 mg/kg or greater in the SSL soil. Effects on the reproduction parameters such as a decrease in the number of juveniles after 56 d of exposure were observed at the initial CL-20 concentration of 1.6 mg/kg or greater in the RacFor2002 soil, compared to 0.2 mg/kg or greater in the SSL soil. Moreover, low concentrations of CL-20 in SSL soil (approximately 0.1 mg/kg; nominal concentration) were found to reduce the fertility of earthworms. Taken together, the present results show that CL-20 is a reproductive toxicant to the earthworm, with lethal effects at higher concentrations. Its toxicity can be decreased in soils favoring CL-20 adsorption (high organic carbon content).

Detection of COPB2 as a KRAS synthetic lethal partner through integration of functional genomics screens

PubMed Central

Christodoulou, Eleni G.; Yang, Hai; Lademann, Franziska; Pilarsky, Christian; Beyer, Andreas; Schroeder, Michael

2017-01-01

Mutated KRAS plays an important role in many cancers. Although targeting KRAS directly is difficult, indirect inactivation via synthetic lethal partners (SLPs) is promising. Yet to date, there are no SLPs from high-throughput RNAi screening, which are supported by multiple screens. Here, we address this problem by aggregating and ranking data over three independent high-throughput screens. We integrate rankings by minimizing the displacement and by considering established methods such as RIGER and RSA. Our meta analysis reveals COPB2 as a potential SLP of KRAS with good support from all three screens. COPB2 is a coatomer subunit and its knock down has already been linked to disabled autophagy and reduced tumor growth. We confirm COPB2 as SLP in knock down experiments on pancreas and colorectal cancer cell lines. Overall, consistent integration of high throughput data can generate candidate synthetic lethal partners, which individual screens do not uncover. Concretely, we reveal and confirm that COPB2 is a synthetic lethal partner of KRAS and hence a promising cancer target. Ligands inhibiting COPB2 may, therefore, be promising new cancer drugs. PMID:28415695

The effect of high concentrations of glufosinate ammonium on the yield components of transgenic spring wheat (Triticum aestivum L.) constitutively expressing the bar gene.

PubMed

Áy, Zoltán; Mihály, Róbert; Cserháti, Mátyás; Kótai, Éva; Pauk, János

2012-01-01

We present an experiment done on a bar(+) wheat line treated with 14 different concentrations of glufosinate ammonium-an effective component of nonselective herbicides-during seed germination in a closed experimental system. Yield components as number of spikes per plant, number of grains per spike, thousand kernel weight, and yield per plant were thoroughly analysed and statistically evaluated after harvesting. We found that a concentration of glufosinate ammonium 5000 times the lethal dose was not enough to inhibit the germination of transgenic plants expressing the bar gene. Extremely high concentrations of glufosinate ammonium caused a bushy phenotype, significantly lower numbers of grains per spike, and thousand kernel weights. Concerning the productivity, we observed that concentrations of glufosinate ammonium 64 times the lethal dose did not lead to yield depression. Our results draw attention to the possibilities implied in the transgenic approaches.

Effects of Glyphosate-Based Herbicide Sub-Lethal Concentrations on Fish Feeding Behavior.

PubMed

Giaquinto, Percilia Cardoso; de Sá, Marina Borges; Sugihara, Vanessa Seiko; Gonçalves, Bruno Bastos; Delício, Helton Carlos; Barki, Assaf

2017-04-01

Glyphosate-based herbicides are widely used in agricultural systems. Although the target organism are particularly plant organisms, there are numerous studies showing adverse effects in aquatic animals, such as inhibition of acetyl cholinesterase, effects on kidney, liver, and gill and stressors effects. This study analyzed the effects of commercial formulation of glyphosate on feeding behavior in Pacu (Piaractus mesopotamicus). Fish were exposed to three glyphosate concentrations (0.2, 0.6, and 1.8 ppm) for 15 days. At concentrations of 0.2 and 0.6 ppm, food intake decreased on day 13 and then returned to normal on day 15. At the highest glyphosate-based herbicide concentration, 1.8 ppm, food consumption decreased dramatically and did not recover on day 15. This study showed that glyphosate-based herbicide at sub-lethal concentrations can affect feed intake in pacu and consequently inhibits its growth.

Estimation of Median Lethal Concentration of Three Isolates of Beauveria bassiana for Control of Megacopta cribraria (Heteroptera: Plataspidae) Bioassayed on Solid Lygus spp. Diet

PubMed Central

Portilla, Maribel; Jones, Walker; Perera, Omaththage; Seiter, Nick; Greene, Jeremy; Luttrell, Randall

2016-01-01

The kudzu bug, Megacopta cribraria (F.), is an urban nuisance and significant agricultural pest. The median lethal concentrations of three strains of Beauveria bassiana (Balsamo), including the Mississippi Delta native strain (NI8) isolated from Lygus lineolaris (Palisot de Beauvois), the commercial strain BotaniGard® (GHA) (Victor, NY, USA), and the B. bassiana strain isolated from M. cribraria (KUDSC), were estimated on kudzu bug adults. A technique developed to evaluate B. bassiana against L. lineolaris was used. Younger adults (eight days after collection) were treated with NI8 and GHA and older adult (50 days after collection) were treated with NI8, GHA and KUDSC. Higher concentrations (n × 106, n × 107) of NI8 and GHA caused kudzu bug mortality two days after treatment in younger adults and similar concentrations of NI8, GHA, and KUDSC caused mortality one day after treatment in older adults. Lower concentrations (n × 104, n × 105) were not significantly different in mortality between strains. LS50 values of the KUDSC were significantly lower than NI8 and GHA values in older adults. This is the first available information on median lethal concentration of B. bassiana on kudzu bug adults bioassayed on artificial diet. It was determined that B. bassiana (KUDSC and NI8) are highly effective for young adults at very low doses (LC50 1.98–4.98 viable spores per mm2). PMID:27376335

Estimation of Median Lethal Concentration of Three Isolates of Beauveria bassiana for Control of Megacopta cribraria (Heteroptera: Plataspidae) Bioassayed on Solid Lygus spp. Diet.

PubMed

Portilla, Maribel; Jones, Walker; Perera, Omaththage; Seiter, Nick; Greene, Jeremy; Luttrell, Randall

2016-06-30

The kudzu bug, Megacopta cribraria (F.), is an urban nuisance and significant agricultural pest. The median lethal concentrations of three strains of Beauveria bassiana (Balsamo), including the Mississippi Delta native strain (NI8) isolated from Lygus lineolaris (Palisot de Beauvois), the commercial strain BotaniGard(®) (GHA) (Victor, NY, USA), and the B. bassiana strain isolated from M. cribraria (KUDSC), were estimated on kudzu bug adults. A technique developed to evaluate B. bassiana against L. lineolaris was used. Younger adults (eight days after collection) were treated with NI8 and GHA and older adult (50 days after collection) were treated with NI8, GHA and KUDSC. Higher concentrations (n × 10⁶, n × 10⁷) of NI8 and GHA caused kudzu bug mortality two days after treatment in younger adults and similar concentrations of NI8, GHA, and KUDSC caused mortality one day after treatment in older adults. Lower concentrations (n × 10⁴, n × 10⁵) were not significantly different in mortality between strains. LS50 values of the KUDSC were significantly lower than NI8 and GHA values in older adults. This is the first available information on median lethal concentration of B. bassiana on kudzu bug adults bioassayed on artificial diet. It was determined that B. bassiana (KUDSC and NI8) are highly effective for young adults at very low doses (LC50 1.98-4.98 viable spores per mm²).

Lethal/sublethal responses of Daphnia magna to acute norfloxacin contamination and changes in phytoplankton-zooplankton interactions induced by this antibiotic

NASA Astrophysics Data System (ADS)

Pan, Ying; Yan, Shi-Wei; Li, Ruo-Zhu; Hu, Yi-Wen; Chang, Xue-Xiu

2017-01-01

Although the well-known antibiotic norfloxacin (NOR) is recognized as an important environmental pollutant, little is known about its impacts on ecological processes, particularly on species interactions. In this paper, we quantified Daphnia magna (Crustacea, Cladocera) responses in mortality rate at lethal NOR concentrations (0, 25, 50, 100, 200, 300 and 400 mg L-1), and in heartbeat rate, swimming behavior and feeding rate (on the green alga Chlorella pyrenoidosa) at sublethal NOR concentrations (0, 25, 50 and 100 mg L-1) to determine the effects of this antibiotic in plankton systems. In 96-h-long lethal experiment, mortality rates of D. magna increased significantly with increasing NOR concentration and exposure time. In sublethal experiments, heartbeat rate decreased, while time ratio of vertical to horizontal swimming (TVH) and the duration of quiescence increased in D. magna individuals exposed to increasing NOR concentrations after 4 and 12 h of exposure. These collectively led to decreases in both average swimming ability and feeding rate, consistent with the positive relationship between average swimming ability and feeding rate. Overall, results indicate that, by affecting zooplankton heartbeat rate and behavior, NOR decreased feeding efficiency of D. magna even at low doses, therefore, it might seriously compromise ecosystem health and function.

50 CFR 21.51 - Depredation order for resident Canada geese at agricultural facilities.

Code of Federal Regulations, 2010 CFR

2010-10-01

... management of resident Canada geese, as defined in § 21.3. (b) What is the depredation order for resident... producers (or their employees or agents) to conduct and implement various components of the depredation... goose management tools to the extent they deem appropriate. To minimize lethal take, agricultural...

Metabolic Response of Escherichia coli upon Treatment with Hypochlorite at Sub-Lethal Concentrations

PubMed Central

Winter, Jeannette; Eisenreich, Wolfgang

2015-01-01

Hypochlorite is a reactive oxygen species that is worldwide as an antibacterial disinfectant. Hypochlorite exposure is known to cause oxidative damage to DNA and proteins. As a response to these effects, the metabolite profiles of organisms treated with sub-lethal doses of hypochlorite are assumed to be severely modified; however, the nature of these changes is hardly understood. Therefore, using nuclear magnetic resonance spectroscopy and gas chromatography-coupled mass spectrometry, we analyzed the time-dependent impact of hypochlorite exposure with a sub-lethal concentration (50 µM) on the metabolite profile of the Escherichia coli strain MG1655. Principle component analysis clearly distinguished between the metabolite profiles of bacteria treated for 0, 5,10, 20, 40, or 60 min. Major changes in the relative amounts of fatty acids, acetic acid, and formic acid occurred within the first 5 min. Comparative gas chromatography-coupled mass spectrometry analyses revealed that the amounts of free methionine and alanine were significantly decreased in the treated cells, demonstrating their susceptibility to hypochlorite exposure. The concentrations of succinate, urea, orotic acid, 2-aminobutyric acid, and 2-hydroxybutyric acid were also severely affected, indicating general changes in the metabolic network by hypochlorite. However, most metabolite levels relaxed to the reference values of untreated cells after 40–60 min, reflecting the capability of E. coli to rapidly adapt to environmental stress factors such as the presence of sub-lethal oxidant levels. PMID:25932918

Differential sensitivity of developmental stages of the South American toad to a fungicide based on fludioxonil and metalaxyl-M.

PubMed

Svartz, Gabriela; Acquaroni, Mercedes; Pérez Coll, Cristina

2018-06-07

Agricultural fungicide application in Argentina has increased twice since 2008, with Maxim® XL (2.5% fludioxonil +1% metalaxyl-M) as one of the most used fungicide formulation. The toxicity of this pesticide on Rhinella arenarum was assessed by means of continuous (from embryo and larval development) and 24-h pulse exposure standardized bioassays. Lethality was concentration- and exposure time-dependent. Maxim® XL caused a progressive lethal effect along the bioassays with higher toxicity on embryos than larvae, obtaining 50% lethal concentrations at 96, 336, and 504 h of 10.85, 2.89, and 1.71 mg/L for embryos, and 43.94, 11.79, and 5.76 mg/L for larvae respectively. Lethal 504-h no observed effect concentration values for embryos and larvae were 1 and 2.5 mg/L respectively. A stage-dependent toxicity of Maxim® XL was also demonstrated within the embryo development, with early stages more sensitive than the later ones, and blastula as the most sensitive developmental stage. The risk quotients obtained for chronic risk assessment determined a potential threat for the survival and continuity of R. arenarum populations under these conditions. The results indicate that the levels of the fungicide reaching amphibian habitats could be risky for the early development of this amphibian species. This study also emphasizes the necessity to evaluate the chronic effects of fungicides in pesticide risk assessment.

Using Fur to Estimate Mercury Concentrations in Mink

EPA Science Inventory

Total mercury (Hg) concentrations in fur and muscle tissue from mink (Mustela vison) were compared to determine the utility of fur analysis as a non-lethal and convenient method for predicting mercury concentrations in tissues. Sixty nine wild-trapped mink were collected in Rhode...

78 FR 14241 - Acetonitrile; Community Right-to-Know Toxic Chemical Release Reporting

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-05

... 50 values (i.e., the dose of a chemical that is lethal to 50 percent of the test organisms) have been...., the concentration of a chemical that is lethal to 50 percent of the test organisms) of 12,000, 16,000... estimate for acetonitrile in mice was reported to be 2,693 ppm (Ref. 6). A recent study (Ref. 12) reported...

EVALUATION OF A NON-LETHAL SAMPLING TECHNIQUE FOR THE MEASUREMENT OF MERCURY (HG) CONCENTRATIONS AND STABLE-NITROGEN (15N/14N) ISOTOPE RATIOS IN LARGE MOUTH BASS (MICROPTERUS SALMOIDES)

EPA Science Inventory

Contaminant bioaccumulation studies often rely on fish muscle filets as the tissue of choice for the measurement of nitrogen stable isotope ratios ( 15N) and mercury (Hg). Lethal sampling techniques may not be suitable for studies on limited populations from smaller sized aquati...

Effects of depleted uranium on the health and survival of Ceriodaphnia dubia and Hyalella azteca

USGS Publications Warehouse

Kuhne, W.W.; Caldwell, C.A.; Gould, W.R.; Fresquez, P.R.; Finger, S.

2002-01-01

Depleted uranium (DU) has been used as a substitute for the fissionable enriched uranium component of atomic weapons tested at Los Alamos National Laboratory (LANL) (Los Alamos, NM, USA) since the early 1950s, resulting in considerable concentrations of DU in the soils within the test sites. Although the movement of DU into major aquatic systems has been shown to be minimal, there are many small-order ephemeral streams and areas of standing water in canyons throughout LANL that may be affected by inputs of DU via runoff, erosion, and leaching. Ninety-six-hour acute and 7-d chronic toxicity assays were conducted to measure the toxicity of DU on survival and reproduction of Ceriodaphnia dubia. A 14-d water-only assay was conducted to measure survival and growth of Hyalella azteca. The estimated median lethal concentration (LC50) to produce 50% mortality of the test population for the 96-h Ceriodaphnia dubia assay was 10.50 mg/L. Reproductive effects occurred at a lowest-observable-effect concentration ???3.91 mg/L with a no-observable-effect concentration of 1.97 mg/L. The estimated 14-d LC50 for the Hyalella azteca assay was 1.52 mg/L No significant relationship was detected between growth and DU concentrations. Concentrations at which toxicity effects were observed in this study for both invertebrates exceeded concentrations of total uranium observed in runoff from LANL lands. Thus, it is likely that current runoff levels of uranium do not pose a threat to these types of aquatic invertebrates.

WE-FG-BRA-09: Using Graphene Oxide Nano Flakes During Image Guided Radiotherapy to Minimize the Potential of Cancer Recurrence Or Metastasis

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

Toomeh, D; Sajo, E; Hao, Y

Purpose: An increasing number of studies show that cancer stem cells (CSCs) become more invasive (metastatic) and may escape into the blood stream and lymph nodes during radiotherapy (RT), before they have received a lethal dose during RT. Other Studies have shown that Graphene oxide (GO) can selectively inhibit the proliferative expansion of CSCs across multiplicative tumor types. In this study we investigate the feasibility of using GO during radiotherapy (RT) to minimize the escape of CSCs towards preventing cancer metastasis or recurrence. Methods: We hypothesize that sufficient amount of GO nano-flakes (GONFs) released from new design radiotherapy biomaterials (fiducialsmore » or spacers) loaded with the GONFs can reach all tumor cells within typical times of 14 or 21days before the beginning of image-guided radiotherapy (IGRT) following implantation. To test this hypothesis, the space-time diffusion of the GONFs was investigated. Knudsen’s and Cunningham’s numbers were calculated to get the Stokes’ velocities and mobility values, according to these values, diffusion coefficients were calculated. In a previous study it was shown that GONFs concentration of 50 µg/ml were effective. In the diffusion study, 100 µg/ml was chosen as an initial concentration because it has been shown to be relatively non-toxic. Results: The 50 µg/ml concentration in a 2 cm diameter volume of lung tumor could be only achieved using 2 nm and 6 nm GONFs with respective diffusion times of 14 and 21 days. As expected, increased nanoflake size requires longer times to achieve the target 50 µg/ml concentration. Conclusion: The preliminary results indicate the potential of using GONFs delivered via new design radiotherapy biomaterials (e.g. fiducials) to inhibit the proliferative expansion of CSCs. The study avails ongoing in-vivo studies on using GONFs to enhance treatment outcomes for cancer patients.« less

In vitro effects of Salvia officinalis L. essential oil on Candida albicans

PubMed Central

Sookto, Tularat; Srithavaj, Theerathavaj; Thaweboon, Sroisiri; Thaweboon, Boonyanit; Shrestha, Binit

2013-01-01

Objective To determine the anticandidal activities of Salvia officinalis L. (S. officinalis) essential oil against Candida albicans (C. albicans) and the inhibitory effects on the adhesion of C. albicans to polymethyl methacrylate (PMMA) resin surface. Methods Disc diffusion method was first used to test the anticandidal activities of the S. officinalis L. essential oil against the reference strain (ATCC 90028) and 2 clinical strains of C. albicans. Then the minimal inhibitory concentration (MIC) and minimal lethal concentration (MLC) were determined by modified membrane method. The adhesion of C. albicans to PMMA resin surface was assessed after immersion with S. officinalis L. essential oil at various concentrations of 1×MIC, 0.5×MIC and 0.25×MIC at room temperature for 30 min. One-way ANOVA was used to compare the Candida cell adhesion with the pretreatment agents and Tukey's test was used for multiple comparisons. Results S. officinalis L. essential oil exhibited anticandidal activity against all strains of C. albicans with inhibition zone ranging from 40.5 mm to 19.5 mm. The MIC and MLC of the oil were determined as 2.780 g/L against all test strains. According to the effects on C. albicans adhesion to PMMA resin surface, it was found that immersion in the essential oil at concentrations of 1×MIC (2.780 g/L), 0.5×MIC (1.390 g/L) and 0.25×MIC (0.695 g/L) for 30 min significantly reduced the adhesion of all 3 test strains to PMMA resin surface in a dose dependent manner (P<0.05). Conclusions S. officinalis L. essential oil exhibited anticandidal activities against C. albicans and had inhibitory effects on the adhesion of the cells to PMMA resin surface. With further testing and development, S. officinalis essential oil may be used as an antifungal denture cleanser to prevent candidal adhesion and thus reduce the risk of candida-associated denture stomatitis. PMID:23646301

Effects of sub-lethal neurite outgrowth inhibitory concentrations of chlorpyrifos oxon on cytoskeletal proteins and acetylcholinesterase in differentiating N2a cells

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

Flaskos, J., E-mail: flaskos@vet.auth.gr; Nikolaidis, E.; Harris, W.

2011-11-15

Previous work in our laboratory has shown that sub-lethal concentrations (1-10 {mu}M) of chlorpyrifos (CPF), diazinon (DZ) and diazinon oxon (DZO) inhibit the outgrowth of axon-like neurites in differentiating mouse N2a neuroblastoma cells concomitant with altered levels and/or phosphorylation state of axonal cytoskeleton and growth-associated proteins. The aim of the present work was to determine whether chlorpyrifos oxon (CPO) was capable of inhibiting N2a cell differentiation in a similar manner. Using experimental conditions similar to our previous work, sub-lethal concentrations (1-10 {mu}M) of CPO were found to inhibit N2a cell differentiation. However, unlike previous studies with DZ and DZO, theremore » was a high level of sustained inhibition of acetylcholinesterase (AChE) in CPO treated cells. Impairment of neurite outgrowth was also associated with reduced levels of growth associated protein-43 and neurofilament heavy chain (NFH), and the distribution of NFH in cells stained by indirect immunofluorescence was disrupted. However, in contrast to previous findings for DZO, the absolute level of phosphorylated NFH was unaffected by CPO exposure. Taken together, the findings suggest that sub-lethal concentrations of CPO inhibit axon outgrowth in differentiating N2a cells and that this effect involves reduced levels of two proteins that play key roles in axon outgrowth and maintenance. Although the inhibition of neurite outgrowth is unlikely to involve AChE inhibition directly, further work will help to determine whether the persistent inhibition of AChE by CPO can account for the different effects induced by CPO and DZO on the levels of total and phosphorylated NFH. -- Highlights: Black-Right-Pointing-Pointer Sub-lethal levels of chlorpyrifos oxon inhibit neurite outgrowth in N2a cells Black-Right-Pointing-Pointer Acetylcholinesterase exhibits sustained inhibition throughout exposure Black-Right-Pointing-Pointer The levels of neurofilament heavy chain and GAP-43 protein are reduced Black-Right-Pointing-Pointer Neurofilament heavy chain forms aggregates in cell bodies Black-Right-Pointing-Pointer Thus at least two axon-associated cytoskeletal proteins are disrupted by this agent.« less

Three homicides with darts tainted with succinylcholine: autopsy and toxicology.

PubMed

Xing, Jingjun; Li, Wenhe; Tong, Fang; Liang, Yue; He, Guanglong; Zhou, Yiwu

2016-11-01

In emergency departments, intoxication with the muscle relaxant succinylcholine (SUX) often leads to a potentially lethal respiratory paralysis or other deleterious side effects. However, homicide cases with SUX poisoning are very rare because the toxic or lethal concentration ranges of SUX have not yet been determined. We described three uncommon homicide cases due to acute poisoning by darts contaminated with SUX. All the victims died quickly (less than 30 min) after being shot by an especially designed dart gun. Succinylmonocholine (SMC), a metabolite of SUX, was used as a marker to detect the latter. HPLC-MS/MS analysis demonstrated the presence of SUX in the droplet residues of the darts and SMC in the blood and urine in all cases. SMC concentrations of 0.45, 14.0, and 17.9 ng/ml were detected in the victims' blood and 259.0 ng/ml in the urine from the third case. The main pathological changes consisted of hemorrhage of the injured soft tissues, visceral congestion, severe pulmonary edema, and multifocal petechial hemorrhage of the heart and lungs. Taken together, the findings supported a diagnosis of fatal SUX poisoning. Futhermore, our study provided a reference for the lethal concentrations of SUX poisoning.

Developmental toxicity of p,p'-dichlorodiphenyltrichloroethane, 2,4,6-trinitrotoluene, their metabolites, and benzo[a]pyrene in Xenopus laevis embryos.

PubMed

Saka, Masahiro

2004-04-01

Since 1995, high incidences of deformed frogs have been documented in Kitakyushu, Japan. In this area, relatively high concentrations of DDT, trinitrotoluene (TNT), their metabolites (p,p'-dichlorodiphenyldichloroethylene [DDE], p,p'-dichlorodiphenyldichloroethane [DDD], 2-amino-4,6-dinitrotoluene [2ADNT], and 4-amino-2,6-dinitrotoluene [4ADNT]), and benzo[a]pyrene [BaP]) have been identified from field samples. I used a standardized assay with Xenopus laevis embryos (frog embryo teratogenesis assay--Xenopus, FETAX) to examine the developmental toxicity of these compounds. Both DDE and BaP were considered nearly nontoxic in embryonic development because they induced low (< 10%) mortality and malformation incidence even at the highest concentrations tested (DDE, 393 microM; BaP, 13.2 microM). The DDD (96-h median lethal concentration [LC50] = 44.1 microM, 96-h median effective concentration [EC50] for malformation = 14.9 microM) was more lethal and teratogenic than its parent compound, DDT (96-h LC50 = 101 microM, 96-h EC50 = 41.5 microM). Predominant symptoms observed were axial malformations (DDT and DDD) and irregular gut coiling (DDT). However, DDT and DDD should not act as major lethal or teratogenic toxicants in the aquatic environment within a short-term exposure via water because their 96-h LC50 and 96-h EC50 values were extremely high, considering their low solubility in water. The TNT (96-h LC50 = 16.7 microM) was more lethal than 2ADNT (96-h LC50 = 166 microM) or 4ADNT (96-h LC50 = 115 microM). Although 4ADNT (96-h EC50 = 85.8 microM) induced various tadpole malformations, it was a weak teratogen compared with TNT (96-h EC50 = 9.78 microM) and 2ADNT (96-h EC50 = 16.9 microM). The most typical malformations observed were axial malformations, eye abnormalities (TNT), edema, and irregular gut coiling (2ADNT and 4ADNT). The 96-h LC50 and 96-h EC50 values of TNT, 2ADNT, and 4ADNT were lower than their saturated concentrations in water. Therefore, these nitroaromatic compounds may show lethal or teratogenic effects on aquatic animals if their habitats are severely contaminated with TNT.

Baseline blood Pb levels of black-necked stilts on the upper Texas coast

USGS Publications Warehouse

Riecke, Thomas V.; Conway, Warren C.; Haukos, David A.; Moon, Jena A.; Comer, Christopher E.

2015-01-01

There are no known biological requirements for lead (Pb), and elevated Pb levels in birds can cause a variety of sub-lethal effects and mortality. Historic and current levels of Pb in mottled ducks (Anas fulvigula) suggest that environmental sources of Pb remain available on the upper Texas coast. Because of potential risks of Pb exposure among coexisting marsh birds, black-necked stilt (Himantopus mexicanus) blood Pb concentrations were measured during the breeding season. Almost 80 % (n = 120) of 152 sampled stilts exceeded the background threshold (>20 μg/dL) for Pb exposure. However, blood Pb concentrations did not vary by age or gender, and toxic or potentially lethal concentrations were rare (<5 %). Consistent, low-level blood Pb concentrations of black-necked stilts in this study suggest the presence of readily bioavailable sources of Pb, although potential impacts on local stilt populations remain unclear.

A Method for Evaluating Insecticide Efficacy against Bed Bug, Cimex lectularius, Eggs and First Instars.

PubMed

Campbell, Brittany E; Miller, Dini M

2017-03-15

Standard toxicity evaluations of insecticides against insect pests are primarily conducted on adult insects. Evaluations are based on a dose-response or concentration-response curve, where mortality increases as the dose or concentration of an insecticide is increased. Standard lethal concentration (LC50) and lethal dose (LD50) tests that result in 50% mortality of a test population can be challenging for evaluating toxicity of insecticides against non-adult insect life stages, such as eggs and early instar or nymphal stages. However, this information is essential for understanding insecticide efficacy in all bed bug life stages, which affects control and treatment efforts. This protocol uses a standard dipping bioassay modified for bed bug eggs and a contact insecticidal assay for treating nymphal first instars. These assays produce a concentration-response curve to further quantify LC50 values for insecticide evaluations.

Acute toxicity and biodegradation of endosulfan by the polychaeta Perinereis aibuhitensis in an indoor culture

NASA Astrophysics Data System (ADS)

Kang, Kyoung Ho; Zhang, Litao; Zhang, Zhifeng; Sui, Zhenghong; Hur, Junwook

2013-01-01

The polychaete Perinereis aibuhitensis, a key species in estuarine ecosystems, can improve the culture condition of sediment. Endosulfan is an organochlorine pesticide used globally to control insects and mites; however, it is a source of pollution in aquaculture as a result of runoff or accidental release. In this study, we evaluated the toxicity of endosulfan to polychaeta and its ability to improve polluted sediment. Specifically, the effects of a series of endosulfan concentrations (0, 1.25, 2.5, 5, 10, 15, and 20 mg/L) were investigated, and the results indicated that the 24-h median lethal concentration (24-h LC50) was 55.57 mg/L, while the 48-h median lethal concentration (48-h LC50) was 15.56 mg/L, and the safe concentration was about 1.556 mg/L. In a 30-d exposure experiment, the animal specimen could decompose endosulfan effectively while improving endosulfan-polluted aquatic sediment.

Toxicity, feeding rate and growth rate response to sub-lethal concentrations of anthracene and benzo [a] pyrene in milkfish Chanos chanos (Forskkal).

PubMed

Palanikumar, L; Kumaraguru, A K; Ramakritinan, C M; Anand, M

2013-01-01

The feeding rate, growth rate and gross conversion efficiency were studied in milkfish Chanos chanos for 28 days of exposure to sub-lethal concentrations of anthracene (1.00, 2.00, 3.00, 6.00 and 12.0 μg l(-1)) and benzo [a] pyrene (0.30, 0.70, 1.40, 2.80 and 5.60 μg l(-1)) under continuous flow through bioassays. Based on survival and growth data, No Observed Effect Concentration; Lowest Observed Effect Concentration were estimated after 28 days, the values for anthracene were 2.03 and 3.09 μg l(-1), and the values for benzo [a] pyrene were 0.82 and 1.46 μg l(-1), respectively. Anthracene and benzo [a] pyrene exposure caused reduction in feeding and growth rate.

Gamma Radiation Reduced Toxicity of Azoxystrobin Tested on Artemia franciscana.

PubMed

Dvorak, P; Zdarsky, M; Benova, K; Falis, M; Tomko, M

2016-06-01

Fungicide azoxystrobin toxicity was monitored by means of a 96-h biotest with Artemia franciscana nauplius stages after exposure to solutions with concentrations of 0.2, 0.4, 0.6 and 0.8 mg L(-1) irradiated with (60)Co gamma radiation with doses of 1, 2.5, 5 and 10 kGy. The effects of ionization radiation on azoxystrobin toxicity were mainly manifested by a statistically significant reduction of lethality after 72- and 96-h exposure. A maximum reduction of lethality of 72 % was achieved using doses of 1-5 kGy for an azoxystrobin initial concentration of 0.4 mg L(-1) and after 72 h of exposure. At a 96-h exposure, a difference of lethal effects reached up to 70 % for a dose of 10 kGy. The observed effect of gamma ionizing radiation on azoxystrobin toxicity suggest that this approach can be applied as an alternative for a reduction of azoxystrobin residua in food.

Periscopic Spine Surgery

DTIC Science & Technology

2007-01-01

radiation therapy In radiation therapy , the overarching goal is to deliver a lethal dose to the cancerous tissue while minimizing collateral damage to the ...Computer is shown in Figure 6. The exercise protocol is first parsed into a control mode based on the desired activation of configuration space variables...ABSTRACT In this paper, we present the design and implementation of a

Acute toxicity of 353-nonylphenol and its metabolites for zebrafish embryos.

PubMed

Kammann, Ulrike; Vobach, Michael; Wosniok, Werner; Schäffer, Andreas; Telscher, Andreas

2009-03-01

Nonylphenol (NP) can be detected in the aquatic environment all over the world. It is applied as a technical mixture of isomers of which 353-NP is the most relevant both in terms of abundance (about 20% of total mass) and endocrine potential. 353-NP is metabolised in sewage sludge. The aims of the present study were to determine and to compare the acute toxicity of t-NP, 353-NP and its metabolites as well as to discuss if the toxicity of 353-NP changes during degradation. 353-NP and two of its metabolites were synthesised. The zebrafish embryo test was performed according to standard protocols. Several lethal and non-lethal endpoints during embryonal development were reported. NOEL, LOEL and EC50 were calculated. All tested compounds caused lethal as well as non-lethal malformations during embryo development. 353-NP showed a higher toxicity (EC50 for lethal endpoints 6.7 mg/L) compared to its metabolites 4-(3.5-dimethyl-3-heptyl)-2-nitrophenol (EC50 13.3 mg/L) and 4-(3,5-dimethyl-3-heptyl)-2-bromophenol (EC50 27.1 mg/L). In surface water, concentrations of NP are far below the NOEC identified by the zebrafish embryo test. However, in soils and sewage sludge, concentrations may reach or even exceed these concentrations. Therefore, sludge-treated sites close to surface waters should be analysed for NP and its metabolites in order to detect an unduly high contamination due to runoff events. The results of the present study point out that the toxicity of 353-NP probably declines during metabolisation in water, sediment and soil, but does not vanish since the major metabolites exhibit a clear toxic potential for zebrafish embryos. Metabolites of environmental pollutants should be included in the ecotoxicological test strategy for a proper risk assessment.

Effects of raised CO2 concentration on the egg production rate and early development of two marine copepods (Acartia steueri and Acartia erythraea).

PubMed

Kurihara, Haruko; Shimode, Shinji; Shirayama, Yoshihisa

2004-11-01

Direct injection of CO(2) into the deep ocean is receiving increasing attention as a way to mitigate increasing atmospheric CO(2) concentration. To assess the potential impact of the environmental change associated with CO(2) sequestration in the ocean, we studied the lethal and sub-lethal effects of raised CO(2) concentration in seawater on adult and early stage embryos of marine planktonic copepods. We found that the reproduction rate and larval development of copepods are very sensitive to increased CO(2) concentration. The hatching rate tended to decrease, and nauplius mortality rate to increase, with increased CO(2) concentration. These results suggest that the marine copepod community will be negatively affected by the disposal of CO(2). This could decrease on the carbon export flux to the deep ocean and change the biological pump. Clearly, further studies are needed to determine whether ocean CO(2) injection is an acceptable strategy to reduce anthropogenic CO(2).

[Inhibitory effects of Spartina anglica on Heterosigma akashiwo and Prorocenrum micans and the isolation and identification of the algicidal compounds].

PubMed

Xu, Nian-Jun; Tang, Jun; Zhang, Ze-Wei; Yan, Xiao-Jun

2009-10-01

Taking Heterosigma akashiwo and Prorocenrum micans as test materials, the algicidal activity of Spartina anglica against the growth of the two harmful microalgae were investigated, with the algicidal compounds isolated and identified. Lower concentration S. anglica stimulated the growth of H. akashiwo, while high concentration S. anglica inhibited the H. akashiwo growth significantly. The lethal concentration of S. anglica fresh tissue, dry powder, and extracts to H. akashiwo was 4.8 mg x ml(-1), 0.8 mg x ml(-1), and 0.5 mg x ml(-1), respectively. All test concentration S. anglica had obvious inhibitory effects on the growth of P. micans, and the lethal concentration of S. anglica fresh material, dry powder, and extracts was 9.6 mg x ml(-1), 1.6 mg x ml(-1), and 1.25 mg x ml(-1), respectively. Two algicidal compounds in S. anglica were isolated, and identified as isohamnetin-3-O-sophoroside-7-O-rhamnoside and syringetin-3-O-galactoside.

Toxicity of un-ionized ammonia, nitrite, and nitrate to juvenile bay scallops, Argopecten irradians irradians.

PubMed

Widman, James C; Meseck, Shannon L; Sennefelder, George; Veilleux, David J

2008-04-01

Juvenile bay scallops (7.2-26.4 mm) were exposed for 72 h to different concentrations of un-ionized ammonia, nitrite, or nitrate. Using the Trimmed Spearman Karber method, 50% lethal concentrations (LC(50)) and 95% confidence limits were calculated individually for each. Un-ionized ammonia concentrations above 1.0 mg N-NH(3)/L resulted in 100% scallop mortality within 72 h. The 72-h LC(50) for un-ionized ammonia was calculated at 0.43 mg N/L. At nitrite concentrations of 800 mg N/L or higher 100% mortality was observed. The 72-h LC(50) for nitrite was calculated at 345 mg N/L. Nitrate was the least toxic, with 100% mortality observed at a concentration of 5000 mg N/L. The calculated nitrate 72-h LC(50) was 4453 mg N/L. Our results indicate that un-ionized ammonia is the most lethal nitrogenous waste component to bay scallops.

Effects of turbidity, sediment, and polyacrylamide on native freshwater mussels

USGS Publications Warehouse

Buczek, Sean B.; Cope, W. Gregory; McLaughlin, Richard A.; Kwak, Thomas J.

2018-01-01

Turbidity is a ubiquitous pollutant adversely affecting water quality and aquatic life in waterways globally. Anionic polyacrylamide (PAM) is widely used as an effective chemical flocculent to reduce suspended sediment (SS) and turbidity. However, no information exists on the toxicity of PAM‐flocculated sediments to imperiled, but ecologically important, freshwater mussels (Unionidae). Thus, we conducted acute (96 h) and chronic (24 day) laboratory tests with juvenile fatmucket (Lampsilis siliquoidea) and three exposure conditions (nonflocculated settled sediment, SS, and PAM‐flocculated settled sediment) over a range of turbidity levels (50, 250, 1,250, and 3,500 nephelometric turbidity units). Survival and sublethal endpoints of protein oxidation, adenosine triphosphate (ATP) production, and protein concentration were used as measures of toxicity. We found no effect of turbidity levels or exposure condition on mussel survival in acute or chronic tests. However, we found significant reductions in protein concentration, ATP production, and oxidized proteins in mussels acutely exposed to the SS condition, which required water movement to maintain sediment in suspension, indicating responses that are symptoms of physiological stress. Our results suggest anionic PAM applied to reduce SS may minimize adverse effects of short‐term turbidity exposure on juvenile freshwater mussels without eliciting additional lethal or sublethal toxicity.

Acute toxicity of 6 neonicotinoid insecticides to freshwater invertebrates.

PubMed

Raby, Melanie; Nowierski, Monica; Perlov, Dmitri; Zhao, Xiaoming; Hao, Chunyan; Poirier, David G; Sibley, Paul K

2018-05-01

Neonicotinoids are a group of insecticides commonly used in agriculture. Due to their high water solubility, neonicotinoids can be transported to surface waters and have the potential to be toxic to aquatic life. The present study assessed and compared the acute (48- or 96-h) toxicity of 6 neonicotinoids (acetamiprid, clothianidin, dinotefuran, imidacloprid, thiacloprid, and thiamethoxam) to 21 laboratory-cultured and field-collected aquatic invertebrates spanning 10 aquatic arthropod orders. Test conditions mimicked species' habitat, with lentic taxa exposed under static conditions, and lotic taxa exposed under recirculating systems. Median lethal concentrations (LC50s) and median effect concentrations (EC50s; immobility) were calculated and used to construct separate lethal- and immobilization-derived species sensitivity distributions for each neonicotinoid, from which 5th percentile hazard concentrations (HC5s) were calculated. The results showed that the most sensitive invertebrates were insects from the orders Ephemeroptera (Neocloeon triangulifer) and Diptera (Chironomus dilutus), whereas cladocerans (Daphnia magna, Ceriodaphnia dubia) were the least sensitive. The HC5s were compared with neonicotinoid environmental concentrations from Ontario (Canada) monitoring studies. For all neonicotinoids except imidacloprid, the resulting hazard quotients indicated little to no hazard in terms of acute toxicity to aquatic communities in Ontario freshwater streams. For the neonicotinoid imidacloprid, a moderate hazard was found when only invertebrate immobilization, and not lethality, data were considered. Environ Toxicol Chem 2018;37:1430-1445. © 2018 SETAC. © 2018 SETAC.

The individual tolerance concept is not the sole explanation for the probit dose-effect model

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

Newman, M.C.; McCloskey, J.T.

2000-02-01

Predominant methods for analyzing dose- or concentration-effect data (i.e., probit analysis) are based on the concept of individual tolerance or individual effective dose (IED, the smallest characteristic dose needed to kill an individual). An alternative explanation (stochasticity hypothesis) is that individuals do not have unique tolerances: death results from stochastic processes occurring similarly in all individuals. These opposing hypotheses were tested with two types of experiments. First, time to stupefaction (TTS) was measured for zebra fish (Brachydanio rerio) exposed to benzocaine. The same 40 fish were exposed during five trials to test if the same order for TTS was maintainedmore » among trials. The IED hypothesis was supported with a minor stochastic component being present. Second, eastern mosquitofish (Gambusia holbrooki) were exposed to sublethal or lethal NaCl concentrations until a large portion of the lethally exposed fish died. After sufficient time for recovery, fish sublethally exposed and fish surviving lethal exposure were exposed simultaneously to lethal NaCl concentrations. No statistically significant effect was found of previous exposure on survival time but a large stochastic component to the survival dynamics was obvious. Repetition of this second type of test with pentachlorophenol also provided no support for the IED hypothesis. The authors conclude that neither hypothesis alone was the sole or dominant explanation for the lognormal (probit) model. Determination of the correct explanation (IED or stochastic) or the relative contributions of each is crucial to predicting consequences to populations after repeated or chronic exposures to any particular toxicant.« less

A hepatic metabolomics-based diagnostic approach to assess lethal toxicity of dithiocarbamate fungicide polycarbamate in three marine fish species.

PubMed

Hano, Takeshi; Ohkubo, Nobuyuki; Mochida, Kazuhiko

2017-04-01

The present study was performed to evaluate the toxic effect of the dithiocarbamate fungicide polycarbamate (PC) on the hepatic metabolic profiles of three marine fish species, red sea bream (Pagrus major), spotted halibut (Verasper variegatus), and marbled flounder (Pleuronectes yokohamae). First, juvenile fish were exposed to graded concentrations of PC for 96h; the 96-h LC 50 values obtained were 22-29, 239-553, and 301-364µgL -1 for red sea bream, spotted halibut, and marbled flounder, respectively, indicating that red sea bream possessed higher sensitivity to PC than the two benthic species. Second, the fish were exposed to lethal-equivalent concentration (H group) or sub-lethal (one-tenth of the H group concentrations; L group) for 24 and 96h and gas-chromatography based metabolomics approach was employed to explore the crucial biomarker metabolite associated with lethal toxicity. Of the 53 metabolites identified, only reduced glutathione (GSH) was consistently elevated in the H group for the three fish species at 96h. The calculated cut-off value of GSH (mM) based on receiver operating curve analysis between H group and the other treatment groups (control, solvent control, and L group) was obtained at 0.56mM, which allowed to distinguish between the groups with high confidence for the three fish species. These results are the first to demonstrate the potential of using GSH as a possible biomarker metabolite and its usefulness of threshold cut-off value for diagnosing life-threatening health conditions of fish. Copyright © 2016 Elsevier Inc. All rights reserved.

Relative toxicity testing of spacecraft materials. 1: Spacecraft materials. [lethality of pyrolysates

NASA Technical Reports Server (NTRS)

Lawrence, W. H.

1980-01-01

In chamber thermodegradation procedures were used to access the lethality to rats of the pyrolysis/combustion products of three foams, an adhesive backed metallic tape and RTV silicone rubber adhesive sealant used in spacecraft construction. The role of carbon monoxide in the overall pyrolysate toxicity was also investigated. Post exposure observation of the rats, histological evaluation of selected organs, carbon monoxide concentration in the chamber atmosphere during exposure and the percent carboxyhemoglobin in the animals expiring in the chamber are discussed. Thermogravimetric analysis and dosage response results are given. The lethal effect of the RTV silicon appears to be due to physical obstruction of the respiratory system by particulate matter from pyrolysis.

Development of a Chronic Toxicity Testing Method for Daphnia pulex

DTIC Science & Technology

2015-08-01

survivorship) and sublethal endpoints (e.g., growth, reproduction) and are in concept more sensitive than acute lethality tests. • Control– negative ...organism is unable to swim /move after gentle agitation with a transfer pipette but is still alive • LC50-Lethal concentration at which a median effect on...from Zumwalt et al. (1994) The original apparatus uses water splitting channels to perform water changes on 8 beakers at once; the modified apparatus

The responses of the estuarine bivalve mollusc Scrobicularia to the first hydrolytic product of the insecticide Sevin ®

NASA Astrophysics Data System (ADS)

Akberali, H. B.; Trueman, E. R.; Black, J. E.; Hewitt, C.

1982-10-01

The effects of 1-naphthol, the first hydrolytic product of the insecticide Sevin ®, have been studied on the estuarine bivalve Scrobicularia. Median lethal times for 5 and 10 mg l -1 1-naphthol were 15 and 9 days respectively. Final concentrations of 1, 5, 10 and 20 mg l -1 of 1-naphthol resulted in the immediate contraction of the isolated siphon. The contractions were more pronounced at higher concentrations. Application of the same range of concentrations of 1-naphthol to intact Scrobicularia resulted in valve closure and bradycardia. The similarity between the results of median lethal time experiments and the isolated siphonal and behavioural responses of Scrobicularia indicates the feasibility of the use of the isolated siphon preparations to make rapid assessments of environmental stress conditions.

Evaluation of the dust and methanol extracts of Garcinia kolae for the control of Callosobruchus maculatus (F.) and Sitophilus zeamais (Mots)

PubMed Central

Ogunleye, R.F.; Adefemi, S.O.

2007-01-01

Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects; none of them died even at 3 d after treatment. The methanol extracts, however, had rapid lethal effects on both C. maculatus and S. zeamais. The mortality of C. maculatus by the lowest concentration of methanol extracts ranged from 95%~100% whereas in S. zeamais, the mortality ranged from 87.5%~100% and 70%~100% in concentrations of 1 g extract+3 ml methanol and 1 g extract+5 ml methanol, respectively, from 24 to 48 h. The least concentration of 1 g extract+15 ml methanol had no significant lethal effect on Sitophilus zeamais. PMID:18257127

The phototoxicity of phenothiazinium derivatives against Escherichia coli and Staphylococcus aureus.

PubMed

Phoenix, D A; Sayed, Z; Hussain, S; Harris, F; Wainwright, M

2003-10-24

Phenothiazinium dyes, and derivatives, were tested for toxicity to Escherichia coli and Staphylococcus aureus. The dyes were generally lipophilic (log P>1) and showed inherent dark toxicity (minimum lethal concentrations: 3.1-1000 microM). Dye illumination (total light dose of 3.15 J cm(-1) over 30 min) led to up to eight-fold reductions in minimum lethal concentrations. Most of the illuminated dyes showed significant relative singlet oxygen yields (phi'delta: 0.18-1.35) suggesting a type II mechanism of generating a phototoxic response. Although generally up to six-fold more effective against S. aureus, the dyes tested efficiently killed E. coli and may be of particular use in combating Gram-negative pathogens.

Toxicity of dissolved ozone to fish eggs and larvae

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

Asbury, C.; Coler, R.

1980-07-01

To find levels of dissolved residual ozone lethal to fish eggs and larvae during brief exposures, continuous-flow toxicity tests were performed with eggs and larvae of yellow perch (Perca flavescens), and fathead minnow (Pimephales promelas), eggs of white sucker (Catastomus commersoni), and larvae of bluegill sunfish (Lepomis macrochirus). The 50 and 99% lethal concentrations with confidence limits were calculated. Eggs of the species tested were more tolerant than larvae, which were destroyed by very brief exposures (less than 2 minutes) to residuals less than 0.1 mg/1. Because of the sensitivity of the larvae, residual ozone concentrations in natural waters shouldmore » remain well below 50 ..mu..g/1.« less

Endograft collapse following endovascular repair of traumatic aortic injury.

PubMed

Annamalai, Ganesan; Cook, Richard; Martin, Michael

2011-03-01

The advent of endovascular treatment of traumatic thoracic aortic injuries offers a valuable, minimally invasive alternative to open surgical repair. However, there are limitations of the current endovascular stent graft technology for this group of patients. After endovascular repair meticulous follow-up is required with a high index of suspicion for potential complications including the lethal complication of endograft collapse.

Hydrodynamic cavitation: characterization of a novel design with energy considerations for the inactivation of Saccharomyces cerevisiae in apple juice.

PubMed

Milly, P J; Toledo, R T; Kerr, W L; Armstead, D

2008-08-01

A Shockwave Power Reactor consisting of an annulus with a rotating pock-marked inner cylinder was used to induce hydrodynamic cavitation in calcium-fortified apple juice flowing in the annular space. Lethality on Saccharomyces cerevisiae was assessed at processing temperatures of 65 and 76.7 degrees C. Details of the novel equipment design were presented and energy consumption was compared to conventional and pulsed electric fields processing technologies. The mean log cycle reduction of S. cerevisiae was 6.27 CFU/mL and all treatments resulted in nonrecoverable viable cells. Induced lethality from hydrodynamic cavitation on S. cerevisiae exceeded the predicted values based on experimentally determined thermal resistance. Rotation of 3000 and 3600 rpm at flow rates greater than 1.0 L/min raised product temperature from 20 to 65.6 or 76.7 degrees C, respectively, and energy input was less than 220 kJ/kg. Conversion efficiency from electrical to thermal was 55% to 84%. Hydrodynamic cavitation enhanced lethality of spoilage microorganisms in minimally processed juices and reduced energy usage.

Effects of cyanobacterial biomass and purified microcystins on malformations in Xenopus laevis: teratogenesis assay (FETAX).

PubMed

Dvoráková, Dagmar; Dvoráková, Katerina; Bláha, Ludek; Marsálek, Blahoslav; Knotková, Zora

2002-12-01

Xenopus laevis (African clawed frog) embryos in a 96-h teratogenesis assay (FETAX) were exposed to 0-250 microg/L and 500 microg/L of purified microcystin-LR (MCYST-LR) for the estimation of lethality, as well as to equivalent concentrations of biomass containing MCYST-LR (natural water bloom dominated by Microcystis aeruginosa) and biomass without MCYST-LR (bloom dominated by Microcystis wesenbergii). The highest tested concentrations of purified MCYST-LR caused up to 30% lethality after a 96-h exposure, corresponding to a LC(25) of 380 microg/L. Cyanobacterial biomass containing MCYST-LR caused significant lethality up to 50% at the highest tested concentrations (300 mg/L, i.e., 250 microg/L of MCYST-LR). The estimated 96-h LC(25) values varied from 125 mg/L (biomass containing MCYST-LR) up to 232 mg/L (biomass without MCYST-LR). A statistically significant increase in the number of malformed embryos was observed after exposure to cyanobacterial samples. Purified MCYST-LR at and above 25 microg/L significantly increased the number of malformations, with 53% of surviving embryos malformed in the highest tested concentration, 250 microg/L (EC(25) = 27 microg/L). Exposure to the highest concentration of MCYST-LR containing biomass resulted in more than 60% of the embryos being malformed and an EC(25) of 52 mg/L (i.e., 43 microg of MCYST-LR/L). Cyanobacterial biomass with no natural microcystin also induced substantial malformations-about 50% aberrant embryos at the highest concentration, 300 mg/L (EC(25) = 75 mg/L). External additions of purified MCYST-LR to the biomass that was originally without microcystins resulted in a slight additional increase in the rate of malformations (80% at the highest concentration, 300 mg of biomass plus 250 microg of MCYST-LR per liter). A comparison of lethality and effects on malformations (teratogenic index, TI = LC(25)/EC(25)) showed that all samples had significant teratogenic potential in the FETAX assay (TI(MCYST-LR) = 14; TI for biomass with and without microcystin ranged between 2.4 and 3.1, respectively). We conclude that cyanobacterial water blooms can significantly alter the normal development of amphibian embryos. Copyright 2002 Wiley Periodicals, Inc.

1H NMR-Based Metabolomic Analysis of Sub-Lethal Perfluorooctane Sulfonate Exposure to the Earthworm, Eisenia fetida, in Soil

PubMed Central

Lankadurai, Brian P.; Furdui, Vasile I.; Reiner, Eric J.; Simpson, André J.; Simpson, Myrna J.

2013-01-01

1H NMR-based metabolomics was used to measure the response of Eisenia fetida earthworms after exposure to sub-lethal concentrations of perfluorooctane sulfonate (PFOS) in soil. Earthworms were exposed to a range of PFOS concentrations (five, 10, 25, 50, 100 or 150 mg/kg) for two, seven and fourteen days. Earthworm tissues were extracted and analyzed by 1H NMR. Multivariate statistical analysis of the metabolic response of E. fetida to PFOS exposure identified time-dependent responses that were comprised of two separate modes of action: a non-polar narcosis type mechanism after two days of exposure and increased fatty acid oxidation after seven and fourteen days of exposure. Univariate statistical analysis revealed that 2-hexyl-5-ethyl-3-furansulfonate (HEFS), betaine, leucine, arginine, glutamate, maltose and ATP are potential indicators of PFOS exposure, as the concentrations of these metabolites fluctuated significantly. Overall, NMR-based metabolomic analysis suggests elevated fatty acid oxidation, disruption in energy metabolism and biological membrane structure and a possible interruption of ATP synthesis. These conclusions obtained from analysis of the metabolic profile in response to sub-lethal PFOS exposure indicates that NMR-based metabolomics is an excellent discovery tool when the mode of action (MOA) of contaminants is not clearly defined. PMID:24958147

Sub-lethal effects of Vip3A toxin on survival, development and fecundity of Heliothis virescens and Plutella xylostella.

PubMed

Gulzar, Asim; Wright, Denis J

2015-11-01

The assessment of sub-lethal effects is important to interpret the overall insecticide efficacy in controlling insect pest populations. In addition to the lethal effect, sub-lethal effects may also occur in exposed insects. Vegetative insecticidal proteins (Vips) have shown a broad spectrum of insecticidal activity against many insect pest species. In this study the sub-lethal effects of the Bacillus thuringiensis vegetative insecticidal toxin Vip3A on the development and reproduction of Heliothis virescens F. and Plutella xylostella L. were evaluated in the laboratory. The results indicated that the sub-lethal concentration of Vip3A increased the duration of the larval and pupal stages as compared with the control treatment for both species. The percent pupation and percent adult emergence were significantly lower for Vip3A-treated insects. The proportion of pairs that produced eggs and the longevity of adults were not significantly different between treatments. H. virescens and P. xylostella treated with Vip3A showed an 11 and 17 % decrease in their intrinsic rate of increase (rm) respectively compared with untreated insects. The results from this study will be helpful to develop the strategy to incorporate Vip 3A containing crops in an integrated pest management programme.

Evaluation of the Natural Zeolite Lethal Effects on Adults of the Bean Weevil Under Different Temperatures and Relative Humidity Regimes.

PubMed

Floros, George D; Kokkari, Anastasia I; Kouloussis, Nikolaos A; Kantiranis, Nikolaos A; Damos, Petros; Filippidis, Anestis A; Koveos, Dimitris S

2018-02-09

We studied the insecticidal activity of different concentrations of very high quality natural zeolites (zeolitic rock containing 92 wt% clinoptilolite) applied on dry beans. The test species was adult bean weevils Acanthoscelides obtectus (Say; Coleoptera: Bruchidae), and the variables included different temperatures and humidity regimes. At certain natural zeolite concentrations the adult mortality approached 100% within the first day of exposure. The lethal natural zeolite concentration for 50% adult mortality (LD50) was 1.1 g/kg dry beans 1 d after exposure. The temperature had no significant effects on the insecticidal potential of the tested natural zeolite formulations. The lethal time (LT) for 50% adult mortality (LT50), at a concentration of 0.5 g/kg dry beans was 106.429, 101.951, and 90.084 min at 15, 20, and 25°C, respectively. It did not differ significantly. In contrast, relative humidity (RH) and exposure time as well as their interactions had a significant effect on natural zeolite formulation and insecticidal potential. At a constant concentration of 0.5 g/kg dry beans and 25°C at 23%, 34%, 53%, and 88% RH the LT50 ranged from 61.6 to 75.9 min; at 72% RH the LT50 was 110.6 min. The results indicate that natural zeolite at low concentrations is promising for the control of the bean weevil under different temperatures and RH regimes. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Enhancement of P2X(7)-induced pore formation and apoptosis: an early effect of diabetes on the retinal microvasculature.

PubMed

Sugiyama, Tetsuya; Kobayashi, Masato; Kawamura, Hajime; Li, Qing; Puro, Donald G; Kobayshi, Masato

2004-03-01

A sight-threatening complication of diabetes is cell death in retinal capillaries. Currently, the mechanisms responsible for this classic manifestation of diabetic retinopathy remain uncertain. The hypothesis for the current study is that diabetes increases the vulnerability of retinal microvessels to the potentially lethal consequences of having their P2X(7) purinoceptors activated. A pathophysiological role is suspected for these receptor-operated channels because, in addition to transducing retinovascular responses to extracellular adenosine triphosphate (ATP), the sustained opening of these channels can induce the formation of large transmembrane pores. In pericyte-containing retinal microvessels that were freshly isolated from nondiabetic and streptozotocin-injected rats, cells with pores were identified by the uptake of YO-PRO-1. Cell viability was assayed by trypan blue dye exclusion, and cleaved caspase-3 immunoreactivity, TUNEL positivity, and nuclear morphology were used to detect apoptotic cells. Patch-clamp recordings assessed electrophysiological parameters. Activation of P2X(7) receptors caused large pores to form and apoptosis to occur in retinal capillaries of nondiabetic and diabetic rats. Of importance to diabetes, the agonist concentration needed to open pores and trigger apoptosis decreased markedly soon after the onset of streptozotocin-induced hyperglycemia. However, despite this increased sensitivity, diabetes minimally affected the P2X(7)-induced ionic currents. Thus, rather than upregulate the number of functional P2X(7) receptor/channels, diabetes appears to facilitate the channel-to-pore transition that occurs during activation of these purinoceptors. In this way, normally nonlethal concentrations of P2X(7) ligands may trigger apoptosis in microvessels of the diabetic retina. A diabetes-induced increase in the vulnerability of retinal microvessels to the lethal effect of P2X(7) receptor activation may be a previously unrecognized mechanism by which diabetic retinopathy progresses.

Fear and loathing in the benthos: Responses of aquatic insect larvae to the pesticide imidacloprid in the presence of chemical signals of predation risk.

PubMed

Pestana, João L T; Loureiro, Susana; Baird, Donald J; Soares, Amadeu M V M

2009-06-28

The influence of interactions between pesticide exposure and perceived predation risk on the lethal and sub-lethal responses of two aquatic insects was investigated using the pesticide imidacloprid, and a combination of predator-release kairomones from trout and alarm substances from conspecifics. Laboratory experiments examined feeding and respiration rates of the caddisfly Sericostoma vittatum as well as the growth, emergence and respiration rates of the midge Chironomus riparius, exposed to sub-lethal concentrations of imidacloprid. The effects of the two stressors on burrowing behaviour of both species were also assessed. The results show significant effects of environmentally relevant concentrations of imidacloprid on all endpoints studied. Perceived predation risk also elicited sub-lethal effects in C. riparius and S. vittatum, the latter species being less responsive to predation cues. The effects of simultaneous exposure to both types of stressors were assessed using two different approaches: analysis of variance and conceptual models [concentration addition (CA) and independent action (IA)] normally used for the evaluation of contaminant mixture exposure. Both statistical approaches showed no significant interactions on responses in simultaneous exposures in the majority of parameters assessed with only a signification deviation from the reference CA and IA models being found for C. riparius respiration data contrary to the ANOVA results. Exposure to imidacloprid also compromised antipredator behavioural responses of both insect species, with potential negative consequences in terms of mortality from predation in the field. The results obtained demonstrate that natural and anthropogenic stressors can be treated within the same framework providing compatible data for modelling. For an improved interpretation of ecological effects it will be important to expand the mechanistic study of effects of combined exposure to pesticides and perceived predation risk by measuring different endpoints over a wider range of pesticide concentrations.

Comparative chronic toxicity of imidacloprid, clothianidin, and thiamethoxam to Chironomus dilutus and estimation of toxic equivalency factors.

PubMed

Cavallaro, Michael C; Morrissey, Christy A; Headley, John V; Peru, Kerry M; Liber, Karsten

2017-02-01

Nontarget aquatic insects are susceptible to chronic neonicotinoid insecticide exposure during the early stages of development from repeated runoff events and prolonged persistence of these chemicals. Investigations on the chronic toxicity of neonicotinoids to aquatic invertebrates have been limited to a few species and under different laboratory conditions that often preclude direct comparisons of the relative toxicity of different compounds. In the present study, full life-cycle toxicity tests using Chironomus dilutus were performed to compare the toxicity of 3 commonly used neonicotinoids: imidacloprid, clothianidin, and thiamethoxam. Test conditions followed a static-renewal exposure protocol in which lethal and sublethal endpoints were assessed on days 14 and 40. Reduced emergence success, advanced emergence timing, and male-biased sex ratios were sensitive responses to low-level neonicotinoid exposure. The 14-d median lethal concentrations for imidacloprid, clothianidin, and thiamethoxam were 1.52 μg/L, 2.41 μg/L, and 23.60 μg/L, respectively. The 40-d median effect concentrations (emergence) for imidacloprid, clothianidin, and thiamethoxam were 0.39 μg/L, 0.28 μg/L, and 4.13 μg/L, respectively. Toxic equivalence relative to imidacloprid was estimated through a 3-point response average of equivalencies calculated at 20%, 50%, and 90% lethal and effect concentrations. Relative to imidacloprid (toxic equivalency factor [TEF] = 1.0), chronic (lethality) 14-d TEFs for clothianidin and thiamethoxam were 1.05 and 0.14, respectively, and chronic (emergence inhibition) 40-d TEFs were 1.62 and 0.11, respectively. These population-relevant endpoints and TEFs suggest that imidacloprid and clothianidin exert comparable chronic toxicity to C. dilutus, whereas thiamethoxam induced comparable effects only at concentrations an order of magnitude higher. However, the authors caution that under field conditions, thiamethoxam readily degrades to clothianidin, thereby likely enhancing toxicity. Environ Toxicol Chem 2017;36:372-382. © 2016 SETAC. © 2016 SETAC.

Ribavirin protects Syrian hamsters against lethal hantavirus pulmonary syndrome--after intranasal exposure to Andes virus.

PubMed

Ogg, Monica; Jonsson, Colleen B; Camp, Jeremy V; Hooper, Jay W

2013-11-08

Andes virus, ANDV, harbored by wild rodents, causes the highly lethal hantavirus pulmonary syndrome (HPS) upon transmission to humans resulting in death in 30% to 50% of the cases. As there is no treatment for this disease, we systematically tested the efficacy of ribavirin in vitro and in an animal model. In vitro assays confirmed antiviral activity and determined that the most effective doses were 40 µg/mL and above. We tested three different concentrations of ribavirin for their capability to prevent HPS in the ANDV hamster model following an intranasal challenge. While the highest level of ribavirin (200 mg/kg) was toxic to the hamster, both the middle (100 mg/kg) and the lowest concentration (50 mg/kg) prevented HPS in hamsters without toxicity. Specifically, 8 of 8 hamsters survived intranasal challenge for both of those groups whereas 7 of 8 PBS control-treated animals developed lethal HPS. Further, we report that administration of ribavirin at 50 mg/kg/day starting on days 6, 8, 10, or 12 post-infection resulted in significant protection against HPS in all groups. Administration of ribavirin at 14 days post-infection also provided a significant level of protection against lethal HPS. These data provide in vivo evidence supporting the potential use of ribavirin as a post-exposure treatment to prevent HPS after exposure by the respiratory route.

Testing of candidate non-lethal sampling methods for detection of Renibacterium salmoninarum in juvenile Chinook salmon Oncorhynchus tshawytscha

USGS Publications Warehouse

Elliott, Diane G.; McKibben, Constance L.; Conway, Carla M.; Purcell, Maureen K.; Chase, Dorothy M.; Applegate, Lynn M.

2015-01-01

Non-lethal pathogen testing can be a useful tool for fish disease research and management. Our research objectives were to determine if (1) fin clips, gill snips, surface mucus scrapings, blood draws, or kidney biopsies could be obtained non-lethally from 3 to 15 g Chinook salmon Oncorhynchus tshawytscha, (2) non-lethal samples could accurately discriminate between fish exposed to the bacterial kidney disease agent Renibacterium salmoninarum and non-exposed fish, and (3) non-lethal samples could serve as proxies for lethal kidney samples to assess infection intensity. Blood draws and kidney biopsies caused ≥5% post-sampling mortality (Objective 1) and may be appropriate only for larger fish, but the other sample types were non-lethal. Sampling was performed over 21 wk following R. salmoninarum immersion challenge of fish from 2 stocks (Objectives 2 and 3), and nested PCR (nPCR) and real-time quantitative PCR (qPCR) results from candidate non-lethal samples were compared with kidney tissue analysis by nPCR, qPCR, bacteriological culture, enzyme-linked immunosorbent assay (ELISA), fluorescent antibody test (FAT) and histopathology/immunohistochemistry. R. salmoninarum was detected by PCR in >50% of fin, gill, and mucus samples from challenged fish. Mucus qPCR was the only non-lethal assay exhibiting both diagnostic sensitivity and specificity estimates >90% for distinguishing between R. salmoninarum-exposed and non-exposed fish and was the best candidate for use as an alternative to lethal kidney sample testing. Mucus qPCR R. salmoninarum quantity estimates reflected changes in kidney bacterial load estimates, as evidenced by significant positive correlations with kidney R. salmoninaruminfection intensity scores at all sample times and in both fish stocks, and were not significantly impacted by environmentalR. salmoninarum concentrations.

Trace element contamination in feather and tissue samples from Anna’s hummingbirds

USGS Publications Warehouse

Mikoni, Nicole A.; Poppenga, Robert H.; Ackerman, Joshua T.; Foley, Janet E.; Hazlehurst, Jenny; Purdin, Güthrum; Aston, Linda; Hargrave, Sabine; Jelks, Karen; Tell, Lisa A.

2017-01-01

Trace element contamination (17 elements; Be, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Cd, Ba, Hg, Tl, and Pb) of live (feather samples only) and deceased (feather and tissue samples) Anna's hummingbirds (Calypte anna) was evaluated. Samples were analyzed using inductively coupled plasma-mass spectrometry (ICP-MS; 17 elements) and atomic absorption spectrophotometry (Hg only). Mean plus one standard deviation (SD) was considered the benchmark, and concentrations above the mean + 1 SD were considered elevated above normal. Contour feathers were sampled from live birds of varying age, sex, and California locations. In order to reduce thermal impacts, minimal feathers were taken from live birds, therefore a novel method was developed for preparation of low mass feather samples for ICP-MS analysis. The study found that the novel feather preparation method enabled small mass feather samples to be analyzed for trace elements using ICP-MS. For feather samples from live birds, all trace elements, with the exception of beryllium, had concentrations above the mean + 1 SD. Important risk factors for elevated trace element concentrations in feathers of live birds were age for iron, zinc, and arsenic, and location for iron, manganese, zinc, and selenium. For samples from deceased birds, ICP-MS results from body and tail feathers were correlated for Fe, Zn, and Pb, and feather concentrations were correlated with renal (Fe, Zn, Pb) or hepatic (Hg) tissue concentrations. Results for AA spectrophotometry analyzed samples from deceased birds further supported the ICP-MS findings where a strong correlation between mercury concentrations in feather and tissue (pectoral muscle) samples was found. These study results support that sampling feathers from live free-ranging hummingbirds might be a useful, non-lethal sampling method for evaluating trace element exposure and provides a sampling alternative since their small body size limits traditional sampling of blood and tissues. The results from this study provide a benchmark for the distribution of trace element concentrations in feather and tissue samples from hummingbirds and suggests a reference mark for exceeding normal. Lastly, pollinating avian species are minimally represented in the literature as bioindicators for environmental trace element contamination. Given that trace elements can move through food chains by a variety of routes, our study indicates that hummingbirds are possible bioindicators of environmental trace element contamination.

Emergency planning and the acute toxic potency of inhaled ammonia.

PubMed Central

Michaels, R A

1999-01-01

Ammonia is present in agriculture and commerce in many if not most communities. This report evaluates the toxic potency of ammonia, based on three types of data: anecdotal data, in some cases predating World War 1, reconstructions of contemporary industrial accidents, and animal bioassays. Standards and guidelines for human exposure have been driven largely by the anecdotal data, suggesting that ammonia at 5,000-10,000 parts per million, volume/volume (ppm-v), might be lethal within 5-10 min. However, contemporary accident reconstructions suggest that ammonia lethality requires higher concentrations. For example, 33,737 ppm-v was a 5-min zero-mortality value in a major ammonia release in 1973 in South Africa. Comparisons of secondary reports of ammonia lethality with original sources revealed discrepancies in contemporary sources, apparently resulting from failure to examine old documents or accurately translate foreign documents. The present investigation revealed that contemporary accident reconstructions yield ammonia lethality levels comparable to those in dozens of reports of animal bioassays, after adjustment of concentrations to human equivalent concentrations via U.S. Environmental Protection Agency (EPA) procedures. Ammonia levels potentially causing irreversible injury or impairing the ability of exposed people to escape from further exposure or from coincident perils similarly have been biased downwardly in contemporary sources. The EPA has identified ammonia as one of 366 extremely hazardous substances subject to community right-to-know provisions of the Superfund Act and emergency planning provisions of the Clean Air Act. The Clean Air Act defines emergency planning zones (EPZs) around industrial facilities exceeding a threshold quantity of ammonia on-site. This study suggests that EPZ areas around ammonia facilities can be reduced, thereby also reducing emergency planning costs, which will vary roughly with the EPZ radius squared. Images Figure 1 Figure 2 PMID:10417358

The Effects of Ethanol on the Morphological and Biochemical Properties of Individual Human Red Blood Cells.

PubMed

Lee, Sang Yun; Park, Hyun Joo; Best-Popescu, Catherine; Jang, Seongsoo; Park, Yong Keun

2015-01-01

Here, we report the results of a study on the effects of ethanol exposure on human red blood cells (RBCs) using quantitative phase imaging techniques at the level of individual cells. Three-dimensional refractive index tomograms and dynamic membrane fluctuations of RBCs were measured using common-path diffraction optical tomography, from which morphological (volume, surface area, and sphericity); biochemical (hemoglobin (Hb) concentration and Hb content); and biomechanical (membrane fluctuation) parameters were retrieved at various concentrations of ethanol. RBCs exposed to the ethanol concentration of 0.1 and 0.3% v/v exhibited cell sphericities higher than those of normal cells. However, mean surface area and sphericity of RBCs in a lethal alcoholic condition (0.5% v/v) are not statistically different with those of healthy RBCs. Meanwhile, significant decreases of Hb content and concentration in RBC cytoplasm at the lethal condition were observed. Furthermore, dynamic fluctuation of RBC membranes increased significantly upon ethanol treatments, indicating ethanol-induced membrane fluidization.

Haem peroxidase activity in Daphnia magna: a biomarker for sub-lethal toxicity assessments of kerosene-contaminated groundwater.

PubMed

Connon, Richard; Dewhurst, Rachel E; Crane, Mark; Callaghan, Amanda

2003-10-01

A novel biomarker was developed in Daphnia magna to detect organic pollution in groundwater. The haem peroxidase assay, which is an indirect means of measuring oxidase activity, was particularly sensitive to kerosene contamination. Exposure to sub-lethal concentrations of kerosene-contaminated groundwater resulted in a haem peroxidase activity increase by dose with a two-fold activity peak at 25%. Reproduction in D. magna remained unimpaired when exposed to concentrations below 25% for 21 days, and a decline in fecundity was only observed at concentrations above the peak in enzyme activity. The measurement of haem peroxidase activity in D. magna detected sublethal effects of kerosene in just 24 h, whilst offering information on the health status of the organisms. The biomarker may be useful in determining concentrations above which detrimental effects would occur from long-term exposure for fuel hydrocarbons. Moreover, this novel assay detects exposure to chemicals in samples that would normally be classified as non-toxic by acute toxicity tests.

Bioavailability, ecotoxicity, and geological characteristics of trace lead in sediments from two sites on Negro River, Uruguay, South America.

PubMed

Míguez, Diana M; Huertas, Raquel; Carrara, María V; Carnikián, Agustín; Bouvier, María E; Martínez, María J; Keel, Karen; Pioda, Carolina; Darré, Elena; Pérez, Ramiro; Viera, Santiago; Massa, Enrique

2012-04-01

Bioassays of two sites along the Rio Negro in Uruguay indicate ecotoxicity, which could be attributable to trace concentrations of lead in river sediments. Monthly samples at two sites at Baygorria and Bonete locations were analyzed for both particle size and lead. Lead was determined by atomic spectrometry in river water and sediment and particle size by sieving and sedimentation. Data showed that Baygorria's sediments have greater percentage of clay than Bonete's (20.4 and 5.8%, respectively). Lead was measurable in Baygorria's sediments, meanwhile in Bonete's, it was always below the detection limit. In water samples, lead was below detection limit at both sites. Bioassays using sub-lethal growth and survival test with Hyalella curvispina amphipod, screening with bioluminescent bacteria Photobacterium leiognathi, and acute toxicity bioassay with Pimephales promelas fish indicated toxicity at Baygorria, with much less effect at Bonete. Even though no lethal effects could be demonstrated, higher sub-lethal toxicity was found in samples from Baygorria site, showing a possible concentration of the contaminant in the clay fraction.

Cytotoxicity and effect of extraction methods on the chemical composition of essential oils of Moringa oleifera seeds

PubMed Central

Kayode, Rowland Monday Ojo; Afolayan, Anthony Jide

2015-01-01

Renewed interest in natural materials as food flavors and preservatives has led to the search for suitable essential oils. Moringa oleifera seed essential oil was extracted by solvent-free microwave and hydrodistillation. This study assessed its chemical constituents. Cytotoxicity of the oils was investigated using hatchability and lethality tests on brine shrimps. A total of 16 and 26 compounds were isolated from the hydrodistillation extraction (HDE) and solvent-free microwave extraction (SME) oils, respectively, which accounted for 97.515% and 97.816% of total identifiable constituents, respectively. At 24 h when the most eggs had hatched, values of the SME (56.7%) and HDE (60.0%) oils were significantly different (P<0.05) from those of sea water (63.3%) and chloramphenicol (15.0%). Larva lethality was different significantly (P<0.05) between HDE and SME oils at different concentrations and incubation periods. The median lethal concentration (LC50) of the oils was >1000 mg/ml recommended as an index for non-toxicity, which gives the oil advantage over some antioxidant, antimicrobial, therapeutic, and preservative chemicals. PMID:26238543

Effects of DDE and PCB (Aroclor 1260) on experimentally poisoned little brown bats (Myotis lucifugus): Lethal brain concentrations

USGS Publications Warehouse

Clark, D.R.; Stafford, C.J.

1981-01-01

Adult female little brown bats (Myotis lucifugus) were collected in a church attic in North East, Cecil County, Md. Mealworms (Tenebrio molitor) containing organochlorine pollutants were fed to the bats as follows: 5 bats were dosed at 480 ppm DDE, 12 at 150 ppm DDE, 5 at 1000 ppm polychlorinated biphenyl (PCB; Aroclor 1260), and 12 at 15 ppm PCB. Seven other bats were fed untreated mealworms. The objective was to elevate brain levels of DDE and PCB to lethality and measure these concentrations. During 40 d of dosage, one DDE-dosed bat and two PCB-dosed bats died after exhibiting the prolonged tremor that characterizes organochlorine poisoning. After dosage, surviving bats were starved to elevate brain levels of toxicants, and three additional DDE-dosed bats had tremors before dying. The mean brain concentration of DDE diagnostic of death was estimated as 603 ppm, range 540-670 ppm. This mean is 16-18% higher than means for Mexican free-tailed bats (Tadarida brasiliensis) and common grackles (Quiscalus quiscula), and may indicate less sensitivity. Lethal brain concentrations of Aroclor 1260 were 1300 and 1500 ppm. Such values appear to be higher than values (Aroclor 1254) for brown-headed cowbirds (Molothrus ater). During starvation, DDE-dosed bats lost weight about 24% faster than controls. If smaller amounts of stored DDE cause increases in metabolic rates of nonfeeding bats, as during hibernation or migration, the result could be premature energy depletion and increased mortality.

Evaluation of the dust and methanol extracts of Garcinia kolae for the control of Callosobruchus maculatus (F.) and Sitophilus zeamais (Mots).

PubMed

Ogunleye, R F; Adefemi, S O

2007-12-01

Insecticidal effects of different doses of the dust and methanol extracts of Garcinia kolae on Callosobruchus maculatus and Sitophilus zeamais were tested. The dust had no significant effect on the two insects; none of them died even at 3 d after treatment. The methanol extracts, however, had rapid lethal effects on both C. maculatus and S. zeamais. The mortality of C. maculatus by the lowest concentration of methanol extracts ranged from 95%~100% whereas in S. zeamais, the mortality ranged from 87.5% to approximately 100% and 70% to approximately 100% in concentrations of 1 g extract+3 ml methanol and 1 g extract+5 ml methanol, respectively, from 24 to 48 h. The least concentration of 1 g extract+15 ml methanol had no significant lethal effect on Sitophilus zeamais.

Effect of human milk and colostrum on Entamoeba histolytica.

PubMed

Akisu, Ciler; Aksoy, Umit; Cetin, Hasan; Ustun, Sebnem; Akisu, Mete

2004-03-01

Many defense factors of the mother's colostrum or milk protect infants from intestinal, respiratory and systemic infections. In the present study, we investigated the effect of colostrum and mature human milk on E. histolytica parasites in vitro. Samples of human milk were collected from 5 healthy lactating mothers. The medium with human milk at concentrations of 2%, 5% and 10% was obtained. The lethal effect of E. histolytica on the medium supplemented with different concentrations of both colostrum and mature human milk was significant during the first 30 min. We also detected that the results of colostrum and mature human milk were similar. No statistically significant differences were found between same concentrations of colostrum and mature human milk at the same times. Colostrum and mature human milk have significant lethal effect on E. histolytica and protect against its infection in breast fed children.

Leaching of zinc compound from rubber stoppers into the contents of automatic atropine injectors.

PubMed

Ellin, R I; Kaminskis, A; Zvirblis, P; Sultan, W E; Shutz, M B; Matthews, R

1985-07-01

This report describes how a material within the cartridge of an automatic injector contaminated its contents. On prolonged storage, a formulation that contained atropine produced lethality in mice. The toxic material originated from zinc compounds that were present in the rubber stopper and plunger of the container and that subsequently leached into the formulation. The contents of cartridges that contained greater than or equal to 0.75 mg/mL of solubilized zinc were lethal to at least 20% of the mice tested; those that contained 0.42 mg/mL showed no lethality. The problem resulted from the physicochemical properties of the rubber, not the concentration of zinc used in the vulcanization process.

Detection of warfare agents in liquid foods using the brine shrimp lethality assay.

PubMed

Lumor, Stephen E; Diez-Gonzalez, Francisco; Labuza, Theodore P

2011-01-01

The brine shrimp lethality assay (BSLA) was used for rapid and non-specific detection of biological and chemical warfare agents at concentrations considerably below that which will cause harm to humans. Warfare agents detected include T-2 toxin, trimethylsilyl cyanide, and commercially available pesticides such as dichlorvos, diazinon, dursban, malathion, and parathion. The assay was performed by introducing 50 μL of milk or orange juice contaminated with each analyte into vials containing 10 freshly hatched brine shrimp nauplii in seawater. This was incubated at 28 °C for 24 h, after which mortality was determined. Mortality was converted to probits and the LC(50) was determined for each analyte by plotting probits of mortality against analyte concentration (log(10)). Our findings were the following: (1) the lethal effects of toxins dissolved in milk were observed, with T-2 toxin being the most lethal and malathion being the least, (2) except for parathion, the dosage (based on LC(50)) of analyte in a cup of milk (200 mL) consumed by a 6-y-old (20 kg) was less than the respective published rat LD(50) values, and (3) the BSLA was only suitable for detecting toxins dissolved in orange juice if incubation time was reduced to 6 h. Our results support the application of the BSLA for routine, rapid, and non-specific prescreening of liquid foods for possible sabotage by an employee or an intentional bioterrorist act. Practical Application: The findings of this study strongly indicate that the brine shrimp lethality assay can be adapted for nonspecific detection of warfare agents or toxins in food at any point during food production and distribution.

Antibodies are necessary for rVSV/ZEBOV-GP-mediated protection against lethal Ebola virus challenge in nonhuman primates.

PubMed

Marzi, Andrea; Engelmann, Flora; Feldmann, Friederike; Haberthur, Kristen; Shupert, W Lesley; Brining, Douglas; Scott, Dana P; Geisbert, Thomas W; Kawaoka, Yoshihiro; Katze, Michael G; Feldmann, Heinz; Messaoudi, Ilhem

2013-01-29

Ebola viruses cause hemorrhagic disease in humans and nonhuman primates with high fatality rates. These viruses pose a significant health concern worldwide due to the lack of approved therapeutics and vaccines as well as their potential misuse as bioterrorism agents. Although not licensed for human use, recombinant vesicular stomatitis virus (rVSV) expressing the filovirus glycoprotein (GP) has been shown to protect macaques from Ebola virus and Marburg virus infections, both prophylactically and postexposure in a homologous challenge setting. However, the immune mechanisms of protection conferred by this vaccine platform remain poorly understood. In this study, we set out to investigate the role of humoral versus cellular immunity in rVSV vaccine-mediated protection against lethal Zaire ebolavirus (ZEBOV) challenge. Groups of cynomolgus macaques were depleted of CD4+ T, CD8+ T, or CD20+ B cells before and during vaccination with rVSV/ZEBOV-GP. Unfortunately, CD20-depleted animals generated a robust IgG response. Therefore, an additional group of vaccinated animals were depleted of CD4+ T cells during challenge. All animals were subsequently challenged with a lethal dose of ZEBOV. Animals depleted of CD8+ T cells survived, suggesting a minimal role for CD8+ T cells in vaccine-mediated protection. Depletion of CD4+ T cells during vaccination caused a complete loss of glycoprotein-specific antibodies and abrogated vaccine protection. In contrast, depletion of CD4+ T cells during challenge resulted in survival of the animals, indicating a minimal role for CD4+ T-cell immunity in rVSV-mediated protection. Our results suggest that antibodies play a critical role in rVSV-mediated protection against ZEBOV.

Standardization of inactivated H5N2 influenza vaccine and efficacy against lethal A/Chicken/Pennsylvania/1370/83 infection.

PubMed

Wood, J M; Kawaoka, Y; Newberry, L A; Bordwell, E; Webster, R G

1985-01-01

The hemagglutinin concentration of beta-propiolactone-inactivated influenza vaccine containing A/Duck/N.Y./189/82 (H5N2) virus was measured by single-radial-immunodiffusion (SRD) test. After administration of vaccine to chickens in Freund's complete adjuvant, vaccine efficacy was assessed by challenge with lethal A/Chicken/Penn./1370/83 (H5N2) virus. SRD potency values correlated with post-vaccination antibody levels and protection against infection.

Minimally invasive transcriptome profiling in salmon: detection of biological response in rainbow trout caudal fin following exposure to environmental chemical contaminants.

PubMed

Veldhoen, Nik; Stevenson, Mitchel R; Skirrow, Rachel C; Rieberger, Kevin J; van Aggelen, Graham; Meays, Cynthia L; Helbing, Caren C

2013-10-15

An increasing number of anthropogenic chemicals have demonstrated potential for disruption of biological processes critical to normal growth and development of wildlife species. Both anadromous and freshwater salmon species are at risk of exposure to environmental chemical contaminants that may affect migratory behavior, environmental fitness, and reproductive success. A sensitive metric in determination of the presence and impact of such environmental chemical contaminants is through detection of changes in the status of gene transcript levels using a targeted quantitative real-time polymerase chain reaction assay. Ideally, the wildlife assessment strategy would incorporate conservation-centered non-lethal practices. Herein, we describe the development of such an assay for rainbow trout, Oncorhynchus mykiss, following an acute 96 h exposure to increasing concentrations of either 17α-ethinyl estradiol or cadmium. The estrogenic screen included measurement of mRNA encoding estrogen receptor α and β isoforms, vitellogenin, vitelline envelope protein γ, cytochrome p450 family 19 subfamily A, aryl hydrocarbon receptor, and the stress indicator, catalase. The metal exposure screen included evaluation of the latter two mRNA transcripts along with those encoding the metallothionein A and B isoforms. Exposure-dependent transcript abundance profiles were detected in both liver and caudal fin supporting the use of the caudal fin as a non-lethally obtained tissue source. The potential for both transcriptome profiling and genotypic sex determination from fin biopsy was extended, in principle, to field-captured Chinook salmon (Oncorhynchus tshawytscha). Copyright © 2013 Elsevier B.V. All rights reserved.

Production of a compound against methicillin resistant Staphylococcus aureus (MRSA) from Streptomyces rubrolavendulae ICN3 & its evaluation in zebrafish embryos

PubMed Central

Kannan, Rajaretinam Rajesh; Iniyan, Appadurai Muthamil; Vincent, Samuel Gnana Prakash

2014-01-01

Background & objectives: Antibiotic resistance in pathogens has become a serious problem worldwide. Therefore, the search for new antibiotics for drug resistanct pathogens is an important endeavor. The present study deals with the production of anti-methicillin resistant Staphylococcus aureus (MRSA) potential of Streptomyces rubrolavendulae ICN3 and evaluation of anti-MRSA compound in zebrafish embryos. Methods: The antibiotic production from S. rubrolavendulae ICN3 was optimized in solid state fermentation and extracted. The antagonistic activity was confirmed against MRSA and purified in silica gel column and reverse phase - HPLC with an absorption maximum at 215 nm. Minimal inhibitory concentration of the compound was determined by broth microdilution method. Zebrafish embryos were used to evaluate the extract/compound for its minimal inhibition studies, influences on heart beat rates, haematopoietic blood cell count and lethal dose values. Results: Streptomyces rubrolavendulae ICN3 showed potent antagonistic activity against MRSA with a zone of 42 mm. The minimum inhibitory concentration was calculated as 500 μg/ml of the crude extract and the purified C23 exhibited 2.5 μg/ml in in vitro assay. The LC50 value of the anti MRSA compound C23 was calculated as 60.49 μg/ml and the MRSA treated embryos survived in the presence of purified compound C23 at a dose of 10 μg/ml. Interpretation & conclusions: Our results suggested that the compound was potent with less toxic effects in zebrafish embryonic model system for MRSA infection. Further structural evaluation and analysis in higher mammalian model system may lead to a novel drug candidate for drug resistant Staphylococcus aureus. PMID:25109726

Structure-Based Systematic Isolation of Conditional-Lethal Mutations in the Single Yeast Calmodulin Gene

PubMed Central

Ohya, Y.; Botstein, D.

1994-01-01

Conditional-lethal mutations of the single calmodulin gene in Saccharomyces cerevisiae have been very difficult to isolate by random and systematic methods, despite the fact that deletions cause recessive lethality. We report here the isolation of numerous conditional-lethal mutants that were recovered by systematically altering phenylalanine residues. The phenylalanine residues of calmodulin were implicated in function both by structural studies of calmodulin bound to target peptides and by their extraordinary conservation in evolution. Seven single and 26 multiple Phe -> Ala mutations were constructed. Mutant phenotypes were examined in a haploid cmd1 disrupted strain under three conditions: single copy, low copy, and overexpressed. Whereas all but one of the single mutations caused no obvious phenotype, most of the multiple mutations caused obvious growth phenotypes. Five were lethal, 6 were lethal only in synthetic medium, 13 were temperature-sensitive lethal and 2 had no discernible phenotypic consequences. Overexpression of some of the mutant genes restored the phenotype to nearly wild type. Several temperature-sensitive calmodulin mutations were suppressed by elevated concentration of CaCl(2) in the medium. Mutant calmodulin protein was detected at normal levels in extracts of most of the lethal mutant cells, suggesting that the deleterious phenotypes were due to loss of the calmodulin function and not protein instability. Analysis of diploid strains heterozygous for all combinations of cmd1-ts alleles revealed four intragenic complementation groups. The contributions of individual phe->ala changes to mutant phenotypes support the idea of internal functional redundancy in the symmetrical calmodulin protein molecule. These results suggest that the several phenylalanine residues in calmodulin are required to different extents in different combinations in order to carry out each of the several essential tasks. PMID:7896089

Evaluating the formulae for integrated lethality in ethylene oxide sterilization using six different endospore forming strains of bacteria, and comparisons of integrated lethality for ethylene oxide and steam systems.

PubMed

Mosley, Gregg A; Gillis, John R; Krushefski, Garrett

2005-01-01

Bacterial endospores from six different species of bacteria were exposed to a spectrum of ethylene oxide (EtO) sterilizing conditions. Temperature was varied from 40 to 60 degrees C and the ethylene oxide concentration was varied from 300 to 750 mg/L. Relative humidity was maintained at 60+/-10% RH. The fraction negative procedure was used to determine the D value for each of the test conditions. Bacterial species tested included Bacillus atrophaeus ATCC # 9372, Bacillus smithii ATCC # 51232, Bacillus subtilis "5230" ATCC # 35021, Bacillus subtilis, DSM # 4181, Bacillus pumilus ATCC # 27142, and Geobacillus stearothermophilus ATCC # 7953. All spore preparations were inoculated on filter paper strips packaged in blue, sterilizable glassine pouches. G. stearothermophilus was the least resistant organism tested. The most resistant organisms tested were B. atrophaeus and B. subtilis "5230". The B. subtilis "5230" strain was slightly more resistant than B. atrophaeus at conditions of 54C and EtO concentrations of 400, 600, and 750 mg/L, as well as at 60C/750mg/L EtO. The other species were between these extremes. This empirical data allowed the application of the recently published formula for converting D values from one set of conditions to another and evaluations of accuracy. The measured D values also allowed the determination of Z values based on temperature variations. These formulae, when applied to process temperatures independent of gas concentration, result in a Z value of approximately 32 degrees C that appears to be similar for all species tested. These data support the application of the previously published formulae 1-6 and allow the same approach to integrated lethality for ethylene oxide processes as is commonly applied to steam sterilization. A review of steam sterilization and related principles was conducted for comparison of integrated lethality for these two methods of sterilization. Errors associated with D values, Z values, extrapolation, and integrated lethality for both methods of sterilization are discussed.

Upper temperature tolerance of loach minnow under acute, chronic, and fluctuating thermal regimes

USGS Publications Warehouse

Widmer, A.M.; Carveth, C.J.; Bonar, Scott A.; Simms, J.R.

2006-01-01

We used four methods to estimate the upper lethal temperature of loach minnow Rhinichthys cobitis: the lethal thermal method (LTM), chronic lethal method (CLM), acclimated chronic exposure (ACE) method with static temperatures, and ACE method with diel temperature fluctuations. The upper lethal temperature of this species ranged between 32??C and 38??C, depending on the method and exposure time; however, temperatures as low as 28??C resulted in slowed growth compared with the control groups. In LTM trials, we increased temperatures 0.3??C/min and death occurred at 36.8 ?? 0.2??C (mean ?? SE) for fish (37-19 mm total length) acclimated to 30??C and at 36.4 ?? 0.07??C for fish acclimated to 25??C. In CLM trials, temperatures were increased more slowly (1??C/d), allowing fish to acclimate. Mean temperature at death was 33.4 ?? 0.1??C for fish 25-35 mm and 32.9 ?? 0.4??C for fish 45-50 mm. In the ACE experiment with static temperatures, we exposed fish for 30 d to four constant temperatures. No fish (20-40 mm) survived beyond 30 d at 32??C and the 30-d temperature lethal to 50% of the test animals was 30.6??C. Growth at static 28??C and 30??C was slower than growth at 25??C, suggesting that fish were stressed at sublethal temperatures. In ACE trials with diel temperature fluctuations of 4,6, and 10??C and a 32??C peak temperature, over 80% of fish (20-40 mm) survived 30 d. Although brief exposures to 32??C were not lethal, the growth of fish in the three fluctuating-temperature treatments was significantly less than the growth at the ambient temperature (25-29??C). To minimize thermal stress and buffer against temperature spikes, we recommend that loach minnow habitat be managed to avoid water temperatures above 28??C. ?? Copyright by the American Fisheries Society 2006.

TPK Sarimukti, Cipatat, West Bandung compost toxicity test using Allium test

NASA Astrophysics Data System (ADS)

Wardini, Trimurti Hesti; Notodarmojo, Peni Astrini

2015-09-01

TPK Sarimukti, Cipatat, West Bandung produced 2 kinds of compost from traditional market waste, liquid and solid compost. The aim of this research is to evaluate toxicity of compost produced in TPK Sarimukti using shallots (Allium cepa). Tests carried out by treated shallots with liquid compost (2,5%, 5%, 10% and 12,5% (w/v)) or solid compost (25%, 50%, 75% and 100% (w/v)) for 48 hours. Results showed reduced root growth rate and mitotic index (MI) in accordance with increased concentrations of compost. Sub lethal concentrations are liquid compost 5% and 10% and solid compost 75%. Lethal concentrations are liquid compost 12,5 % and solid compost 100%. Micronuclei (MN) increased with increase in liquid compost concentration. MN found at very high frequencies in highest solid compost concentration (100%), but very low at lower concentrations. Cells with binuclei and cell necrosis increased with increasing concentrations of given compost. Nuclear anomalies (NA) found in high frequency in 75% and 100% solid compost. Based on research, we can conclude that liquid compost is more toxic because it can reduce MI and root growth rate at lower concentrations than solid compost. Both types of compost have genotoxic properties because it can induce chromosome aberration (CA), MN, binuclei and NA formation.

TPK Sarimukti, Cipatat, West Bandung compost toxicity test using Allium test

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

Wardini, Trimurti Hesti; Notodarmojo, Peni Astrini

TPK Sarimukti, Cipatat, West Bandung produced 2 kinds of compost from traditional market waste, liquid and solid compost. The aim of this research is to evaluate toxicity of compost produced in TPK Sarimukti using shallots (Allium cepa). Tests carried out by treated shallots with liquid compost (2,5%, 5%, 10% and 12,5% (w/v)) or solid compost (25%, 50%, 75% and 100% (w/v)) for 48 hours. Results showed reduced root growth rate and mitotic index (MI) in accordance with increased concentrations of compost. Sub lethal concentrations are liquid compost 5% and 10% and solid compost 75%. Lethal concentrations are liquid compost 12,5more » % and solid compost 100%. Micronuclei (MN) increased with increase in liquid compost concentration. MN found at very high frequencies in highest solid compost concentration (100%), but very low at lower concentrations. Cells with binuclei and cell necrosis increased with increasing concentrations of given compost. Nuclear anomalies (NA) found in high frequency in 75% and 100% solid compost. Based on research, we can conclude that liquid compost is more toxic because it can reduce MI and root growth rate at lower concentrations than solid compost. Both types of compost have genotoxic properties because it can induce chromosome aberration (CA), MN, binuclei and NA formation.« less

Evaluation of Time- and Concentration-dependent Toxic Effect Models for use in Aquatic Risk Assessments, Oral Presentation

EPA Science Inventory

Various models have been proposed for describing the time- and concentration-dependence of toxic effects to aquatic organisms, which would improve characterization of risks in natural systems. Selected models were evaluated using results from a study on the lethality of copper t...

Genotoxic effect of a binary mixture of dicamba- and glyphosate-based commercial herbicide formulations on Rhinella arenarum (Hensel, 1867) (Anura, Bufonidae) late-stage larvae.

PubMed

Soloneski, Sonia; Ruiz de Arcaute, Celeste; Larramendy, Marcelo L

2016-09-01

The acute toxicity of two herbicide formulations, namely, the 57.71 % dicamba (DIC)-based Banvel(®) and the 48 % glyphosate (GLY)-based Credit(®), alone as well as the binary mixture of these herbicides was evaluated on late-stage Rhinella arenarum larvae (stage 36) exposed under laboratory conditions. Mortality was used as an endpoint for determining acute lethal effects, whereas the single-cell gel electrophoresis (SCGE) assay was employed as genotoxic endpoint to study sublethal effects. Lethality studies revealed LC5096 h values of 358.44 and 78.18 mg L(-1) DIC and GLY for Banvel(®) and Credit(®), respectively. SCGE assay revealed, after exposure for 96 h to either 5 and 10 % of the Banvel(®) LC5096 h concentration or 5 and 10 % of the Credit(®) LC5096 h concentration, an equal significant increase of the genetic damage index (GDI) regardless of the concentration of the herbicide assayed. The binary mixtures of 5 % Banvel(®) plus 5 % Credit(®) LC5096 h concentrations and 10 % Banvel(®) plus 10 % Credit(®) LC5096 h concentrations induced equivalent significant increases in the GDI in regard to GDI values from late-stage larvae exposed only to Banvel(®) or Credit(®). This study represents the first experimental evidence of acute lethal and sublethal effects exerted by DIC on the species, as well as the induction of primary DNA breaks by this herbicide in amphibians. Finally, a synergistic effect of the mixture of GLY and DIC on the induction of primary DNA breaks on circulating blood cells of R. arenarum late-stage larvae could be demonstrated.

Lethal and sublethal effects of cypermethrin to Hypsiboas pulchellus tadpoles.

PubMed

Agostini, M Gabriela; Natale, Guillermo S; Ronco, Alicia E

2010-11-01

The study of the effects of the insecticide cypermethrin (CY) technical grade and its Sherpa® commercial formulation on Hypsiboas pulchellus tadpoles assessing lethality, behavior, growth, and abnormalities under standardized laboratory conditions is reported. Observed behaviors were identified and categorized by means of a ranking system according to the loss of mobility. Results of acute lethal effects indicate higher potency for Sherpa® at this level of assessment. All effects on behavior showed an increasing degree of injury as insecticide concentration increased. Organisms exposed to technical grade CY showed lower body length with respect to controls from 3.44 µg CY/L to higher concentrations, whereas those exposed to Sherpa® exhibited lower growth from 0.83 µg CY/L. Both forms of the tested insecticide caused abnormalities between 0.34 and 4.18 µg CY/L, but 100% of malformed individuals was detected from 34.4 µg CY/L for those exposed to the technical grade CY, and from 8.36 µg CY/L for those exposed to Sherpa®. This study proposes the use of easily identifiable and distinguishable sublethal end-points. The high input loads of CY in natural environments, the detected concentrations in the field, in addition to the low levels of this insecticide required to induce sublethal effects (which could eventually lead to death), allow for the conclusion that the insecticide is a risk factor for amphibians inhabiting agroecosystems.

Metal-Polycyclic Aromatic Hydrocarbon Mixture Toxicity in Hyalella azteca. 1. Response Surfaces and Isoboles To Measure Non-additive Mixture Toxicity and Ecological Risk.

PubMed

Gauthier, Patrick T; Norwood, Warren P; Prepas, Ellie E; Pyle, Greg G

2015-10-06

Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their potential to produce non-additive toxicity (i.e., antagonism or potentiation). A review of the lethality of metal-PAH mixtures in aquatic biota revealed that more-than-additive lethality is as common as strictly additive effects. Approaches to ecological risk assessment do not consider non-additive toxicity of metal-PAH mixtures. Forty-eight-hour water-only binary mixture toxicity experiments were conducted to determine the additive toxic nature of mixtures of Cu, Cd, V, or Ni with phenanthrene (PHE) or phenanthrenequinone (PHQ) using the aquatic amphipod Hyalella azteca. In cases where more-than-additive toxicity was observed, we calculated the possible mortality rates at Canada's environmental water quality guideline concentrations. We used a three-dimensional response surface isobole model-based approach to compare the observed co-toxicity in juvenile amphipods to predicted outcomes based on concentration addition or effects addition mixtures models. More-than-additive lethality was observed for all Cu-PHE, Cu-PHQ, and several Cd-PHE, Cd-PHQ, and Ni-PHE mixtures. Our analysis predicts Cu-PHE, Cu-PHQ, Cd-PHE, and Cd-PHQ mixtures at the Canadian Water Quality Guideline concentrations would produce 7.5%, 3.7%, 4.4% and 1.4% mortality, respectively.

Resistance of Trichomonas vaginalis to Metronidazole: Report of the First Three Cases from Finland and Optimization of In Vitro Susceptibility Testing under Various Oxygen Concentrations

PubMed Central

Meri, Taru; Jokiranta, T. Sakari; Suhonen, Lauri; Meri, Seppo

2000-01-01

Trichomonas vaginalis is a globally common sexually transmitted human parasite. Many strains of T. vaginalis from around the world have been described to be resistant to the current drug of choice, metronidazole. However, only a few cases of metronidazole resistance have been reported from Europe. The resistant strains cause prolonged infections which are difficult to treat. T. vaginalis infection also increases the risk for human immunodeficiency virus transmission. We present a practical method for determining the resistance of T. vaginalis to 5-nitroimidazoles. The suggested method was developed by determining the MICs and minimal lethal concentrations (MLCs) of metronidazole and ornidazole for T. vaginalis under various aerobic and anaerobic conditions. Using this assay we have found the first three metronidazole-resistant strains from Finland, although the origin of at least one of the strains seems to be Russia. Analysis of the patient-derived and previously characterized isolates showed that metronidazole-resistant strains were also resistant to ornidazole, and MLCs for all strains tested correlated well with the MICs. The suggested MICs of metronidazole for differentiation of sensitive and resistant isolates are >75 μg/ml in an aerobic 24-h assay and >15 μg/ml in an anaerobic 48-h assay. PMID:10655382

Antimicrobial activity of essential oils against Staphylococcus aureus biofilms.

PubMed

Vázquez-Sánchez, Daniel; Cabo, Marta L; Rodríguez-Herrera, Juan J

2015-12-01

The present study was aimed to evaluate the potential of essential oils to remove the foodborne pathogen Staphylococcus aureus from food-processing facilities. The effectiveness of 19 essential oils against planktonic cells of S. aureus was firstly assessed by minimal inhibitory concentration. Planktonic cells showed a wide variability in resistance to essential oils, with thyme oil as the most effective, followed by lemongrass oil and then vetiver oil. The eight essential oils most effective against planktonic cells were subsequently tested against 48-h-old biofilms formed on stainless steel. All essential oils reduced significantly (p < 0.01) the number of viable biofilm cells, but none of them could remove biofilms completely. Thyme and patchouli oils were the most effective, but high concentrations were needed to achieve logarithmic reductions over 4 log CFU/cm(2) after 30 min exposure. Alternatively, the use of sub-lethal doses of thyme oil allowed to slow down biofilm formation and to enhance the efficiency of thyme oil and benzalkonium chloride against biofilms. However, some cellular adaptation to thyme oil was detected. Therefore, essential oil-based treatments should be based on the rotation and combination of different essential oils or with other biocides to prevent the emergence of antimicrobial-resistant strains. © The Author(s) 2014.

Toxicological Evaluation of Essential Oil From the Leaves of Croton argyrophyllus (Euphorbiaceae) on Aedes aegypti (Diptera: Culicidae) and Mus musculus (Rodentia: Muridae).

PubMed

Cruz, R C D; Silva, S L C E; Souza, I A; Gualberto, S A; Carvalho, K S; Santos, F R; Carvalho, M G

2017-07-01

Plant-derived essential oils can be used as insecticides for vector control. However, to establish their safety, it is necessary to perform toxicological studies. Herein, we evaluated the chemical composition and insecticidal activity of the essential oil from the leaves of Croton argyrophyllus on the third- and fourth-instar larvae and adult Aedes aegypti (L., 1762). We also evaluated the acute toxicity of the essential oil in adult female Mus musculus. The lethal concentration 50 (LC50) and 90 (LC90) of C. argyrophyllus essential oil on larvae of Ae. aegypti were 0.31 and 0.70 mg ml-1, respectively, and 5.92 and 8.94 mg ml-1, respectively, on Ae. aegypti adults. The major components of the essential oil were spathulenol (22.80%), (E)-caryophyllene (15.41%), α-pinene (14.07%), and bicyclogermacrene (10.43%). It also displayed acute toxicity in adults of Mus musculus; the intraperitoneal and oral lethal dose 50 (LD50) were 2,000 mg kg-1 and 2,500 mg kg-1, respectively. The results showed that the essential oil from C. argyrophyllus leaves has insecticidal activity on Ae. aegypti larvae and adults at an average lethal concentration below the median lethal dose needed to cause acute toxicity in the common mouse. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Future Soldiers: Analysis of Entry-Level Performance Requirements and Their Predictors

DTIC Science & Technology

2005-09-01

these future missions; "* New technology such as weapons, tools, and vehicles (e.g., robotics ) and the effect of technological change on personnel...Clusters 1. Close Combat 2. Non Line-of-Sight Fire 3. Surveillance, Intelligence, and Communications 4. Unmanned Vehicle/ Robotics Operator 5. Security...minimized with (a) new materials for ballistic protection, (b) new lethalities, and (c) exoskeletons /artificial muscles. • Infantrymen will experience better

A mutually exclusive stem–loop arrangement in roX2 RNA is essential for X-chromosome regulation in Drosophila

PubMed Central

Ilik, Ibrahim Avsar; Maticzka, Daniel; Georgiev, Plamen; Gutierrez, Noel Marie; Backofen, Rolf; Akhtar, Asifa

2017-01-01

The X chromosome provides an ideal model system to study the contribution of RNA–protein interactions in epigenetic regulation. In male flies, roX long noncoding RNAs (lncRNAs) harbor several redundant domains to interact with the ubiquitin ligase male-specific lethal 2 (MSL2) and the RNA helicase Maleless (MLE) for X-chromosomal regulation. However, how these interactions provide the mechanics of spreading remains unknown. By using the uvCLAP (UV cross-linking and affinity purification) methodology, which provides unprecedented information about RNA secondary structures in vivo, we identified the minimal functional unit of roX2 RNA. By using wild-type and various MLE mutant derivatives, including a catalytically inactive MLE derivative, MLEGET, we show that the minimal roX RNA contains two mutually exclusive stem–loops that exist in a peculiar structural arrangement: When one stem–loop is unwound by MLE, an alternate structure can form, likely trapping MLE in this perpetually structured region. We show that this functional unit is necessary for dosage compensation, as mutations that disrupt this formation lead to male lethality. Thus, we propose that roX2 lncRNA contains an MLE-dependent affinity switch to enable reversible interactions of the MSL complex to allow dosage compensation of the X chromosome. PMID:29066499

MIS approach for diverticula of the esophagus

PubMed Central

2010-01-01

Purpose Diverticula of the esophagus represent a rare pathological entity. Distinct classifications of the disease imply different surgical concepts. Surgery should be reserved for symptomatic patients only. Minimally invasive surgery (MIS) for treatment of esophageal diverticula encompasses rigid and flexible intraluminal endoscopy, thoracoscopy and laparoscopy. We here give an overview on the pathogenesis of esophageal diverticula, the minimally invasive surgical techniques for treatment and the recent literature. Additionally, we present our own experience with MIS for midthoracic diverticula. Methods We analyzed the cases of patients who underwent MIS for midthoracic diverticula with regard to preoperative symptoms, perioperative and follow-up data. Results Three patients (two female, one male, age 79, 78 and 59 years) received thoracoscopic surgery for midthoracic diverticula. All patients reported of dysphagia and regurgitation. In two patients pH-investigation showed pathological reflux but manometry was normal in all patients. Operating time was 205, 135 and 141 minutes. We performed intraoperative intraluminal endoscopy in all patients. There were no intraoperative complications and although no surgical complications occured postoperatively one patient developed pneumonia which advanced to sepsis and lethal multi organ failure. Upon follow-up the two patients did not have recurrent diverticula or a recurrence of previous symptoms. Conclusions Surgery for diverticular disease of the esophagus has been associated with high rates of morbidity and mortality. Despite the lethal non-surgical complication we encountered, with regard to recent publications minimally invasive apporaches to treat patients with symptomatic esophageal diverticula entail lower rates of complications with better long term results in comparison to open surgery. PMID:20952348

Uptake of hexanitrohexaazaisowurtzitane (CL-20) by the earthworm Eisenia fetida through dermal contact.

PubMed

Gong, Ping; Escalon, B Lynn; Hayes, Charolett A; Perkins, Edward J

2008-02-01

The explosive compound hexanitrohexaazaisowurtzitane (CL-20) has been shown to cause both lethal and sublethal (reproductive and neurotoxic) effects in exposed oligochaetes. However, whether worms take up CL-20 and how much CL-20 enters worm bodies leading to toxicity (e.g., lethality) remain to be determined. In the present study, we used high performance liquid chromatography (HPLC) and radiolabeled tracer methods to investigate the CL-20 uptake in the whole worm body after contact exposures. Worms (Eisenia fetida) were exposed to filter paper spiked with non-radioactive or [U-(14)C]-labeled CL-20 for 1-3 d. The radiolabeled tracer method allowed us to detect the parent compound and transformation products in worms exposed to as low as 0.04 microg CL-20 cm(-2) of filter paper. The HPLC method without radiolabeled tracer was far less sensitive with a detection limit of 2.17 microg CL-20 cm(-2). Using the radiolabeled tracer, we were able to demonstrate that the worm body concentration linearly correlated to the filter paper concentration < or =0.34 microg cm(-2) (r=0.94) if no breakdown products are assumed. At higher concentrations, the body concentration increased slowly and saturated at around 11 microg g(-1) dry mass resulting in an estimated lethal critical body burden of 10-15 microg CL-20 g(-1) dry mass. These findings demonstrate that CL-20 or potential transformation products are taken into the earthworm body through dermal contact. This information should prove valuable in assessing the bioaccumulation potential and ecological risks of CL-20.

Assessment of Jatropha curcas L. biodiesel seed cake toxicity using the zebrafish (Danio rerio) embryo toxicity (ZFET) test.

PubMed

Hallare, Arnold V; Ruiz, Paulo Lorenzo S; Cariño, J C Earl D

2014-05-01

Consequent to the growing demand for alternative sources of energy, the seeds from Jatropha curcas remain to be the favorite for biodiesel production. However, a significant volume of the residual organic mass (seed cake) is produced during the extraction process, which raises concerns on safe waste disposal. In the present study, we assessed the toxicity of J. curcas seed cake using the zebrafish (Danio rerio) embryotoxicity test. Within 1-h post-fertilization (hpf), the fertilized eggs were exposed to five mass concentrations of J. curcas seed cake and were followed through 24, 48, and 72 hpf. Toxicity was evaluated based on lethal endpoints induced on zebrafish embryos namely egg coagulation, non-formation of somites, and non-detachment of tail. The lowest concentration tested, 1 g/L, was not able to elicit toxicity on embryos whereas 100 % mortality (based also on lethal endpoints) was recorded at the highest concentration at 2.15 g/L. The computed LC50 for the J. curcas seed cake was 1.61 g/L. No further increase in mortality was observed in the succeeding time points (48 and 72 hpf) indicating that J. curcas seed cake exerted acute toxicity on zebrafish embryos. Sublethal endpoints (yolk sac and pericardial edema) were noted at 72 hpf in zebrafish embryos exposed to higher concentrations. The observed lethal endpoints induced on zebrafish embryos were discussed in relation to the active principles, notably, phorbol esters that have remained in the seed cake even after extraction.

Acute toxicity of polybrominated diphenyl ethers (PBDEs) for turbot (Psetta maxima) early life stages (ELS).

PubMed

Mhadhbi, Lazhar; Fumega, José; Boumaiza, Moncef; Beiras, Ricardo

2012-03-01

The environmental presence of polybrominated diphenyl ethers (PBDEs), among which BDE-47 and BDE-99 are particularly abundant, makes toxicity data necessary to assess the hazard risk posed by PBDE to aquatic organisms. This study examines the effects of BDE-47 and BDE-99 on embryo-larval stages of the marine flatfish turbot. The turbot embryos were exposed at nominal concentrations of BDE-47 and BDE-99 for 6 days. Selected dose levels were relevant for investigating sublethal and lethal effects. Both tested compounds caused lethal toxicity as well as non-lethal malformations during embryo development. We found a high toxic potency of BDE-47 compared to BDE-99 (LC₅₀ values for embryos and larvae, respectively, BDE-47: 27.35 and 14.13 μg L⁻¹; BDE-99: 38.28 and 29.64 μg L⁻¹). The present study shows high sensitivity of fish early life stages (ELS) to PBDE compounds. Based on environmental concentrations of dissolved PBDEs from various aquatic ecosystems, waterborne BDE-47 and BDE-99 pose little risk of acute toxicity to marine fish at relevant environmental concentrations. Turbot fish ELS proved to be an excellent model for the study of ecotoxicity of contaminants in seawater. The results demonstrate harmful effects of PBDE on turbot ELS at concentrations in the range of parts per billion units. In the perspective of risk assessment, ELS endpoints provide rapid, cost-effective and ecologically relevant information, and links should be sought between these short-term tests and effects of long-term exposures in more realistic scenarios.

Insights into the CuO nanoparticle ecotoxicity with suitable marine model species.

PubMed

Rotini, A; Gallo, A; Parlapiano, I; Berducci, M T; Boni, R; Tosti, E; Prato, E; Maggi, C; Cicero, A M; Migliore, L; Manfra, L

2018-01-01

Metal oxide nanoparticles, among them copper oxide nanoparticles (CuO NPs), are widely used in different applications (e.g. batteries, gas sensors, superconductors, plastics and metallic coatings), increasing their potential release in the environment. In aquatic matrix, the behavior of CuO NPs may strongly change, depending on their surface charge and some physical-chemical characteristics of the medium (e.g. ionic strength, salinity, pH and natural organic matter content). Ecotoxicity of CuO NPs to aquatic organisms was mainly studied on freshwater species, few tests being performed on marine biota. The aim of this study was to assess the toxicity of CuO NPs on suitable indicator species, belonging to the ecologically relevant level of consumers. The selected bioassays use reference protocols to identify Effect/Lethal Concentrations (E(L)C), by assessing lethal and sub-lethal endpoints. Mortality tests were performed on rotifer (Brachionus plicatilis), shrimp (Artemia franciscana) and copepod (Tigriopus fulvus). While moult release failure and fertilization rate were studied, as sub-lethal endpoints, on T. fulvus and sea urchin (Paracentrotus lividus), respectively. The size distribution and sedimentation rates of CuO NPs, together with the copper dissolution, were also analyzed in the exposure media. The CuO NP ecotoxicity assessment showed a concentration-dependent response for all species, indicating similar mortality for B. plicatilis (48hLC 50 = 16.94 ± 2.68mg/l) and T. fulvus (96hLC 50 = 12.35 ± 0.48mg/l), followed by A. franciscana (48hLC 50 = 64.55 ± 3.54mg/l). Comparable EC 50 values were also obtained for the sub-lethal endpoints in P. lividus (EC 50 = 2.28 ± 0.06mg/l) and T. fulvus (EC 50 = 2.38 ± 0.20mg/l). Copper salts showed higher toxicity than CuO NPs for all species, with common sensitivity trend as follows: P. lividus ≥ T. fulvus (sublethal endpoint) ≥ B. plicatilis >T. fulvus (lethal endpoint) >A. franciscana. CuO NP micrometric aggregates and high sedimentation rates were observed in the exposure media, with different particle size distributions depending on the medium. The copper dissolution was about 0.16% of the initial concentration, comparable to literature values. The integrated ecotoxicological-physicochemical approach was used to better describe CuO NP toxicity and behavior. In particular, the successful application of ecotoxicological reference protocols allowed to produce reliable L(E)C data useful to identify thresholds and assess potential environmental hazard due to NPs. Copyright © 2017 Elsevier Inc. All rights reserved.

The "Suicide Guard Rail": a minimal structural intervention in hospitals reduces suicide jumps.

PubMed

Mohl, Andreas; Stulz, Niklaus; Martin, Andrea; Eigenmann, Franz; Hepp, Urs; Hüsler, Jürg; Beer, Jürg H

2012-08-04

Jumping from heights is a readily available and lethal method of suicide. This study examined the effectiveness of a minimal structural intervention in preventing suicide jumps at a Swiss general teaching hospital. Following a series of suicide jumps out of the hospital's windows, a metal guard rail was installed at each window of the high-rise building. In the 114 months prior to the installation of the metal guard rail, 10 suicides by jumping out of the hospital's windows occurred among 119,269 inpatients. This figure was significantly reduced to 2 fatal incidents among 104,435 inpatients treated during the 78 months immediately following the installation of the rails at the hospital's windows (χ2 = 4.34, df = 1, p = .037). Even a minimal structural intervention might prevent suicide jumps in a general hospital. Further work is needed to examine the effectiveness of minimal structural interventions in preventing suicide jumps.

The “Suicide Guard Rail”: a minimal structural intervention in hospitals reduces suicide jumps

PubMed Central

2012-01-01

Background Jumping from heights is a readily available and lethal method of suicide. This study examined the effectiveness of a minimal structural intervention in preventing suicide jumps at a Swiss general teaching hospital. Following a series of suicide jumps out of the hospital’s windows, a metal guard rail was installed at each window of the high-rise building. Results In the 114 months prior to the installation of the metal guard rail, 10 suicides by jumping out of the hospital’s windows occurred among 119,269 inpatients. This figure was significantly reduced to 2 fatal incidents among 104,435 inpatients treated during the 78 months immediately following the installation of the rails at the hospital’s windows (χ2 = 4.34, df = 1, p = .037). Conclusions Even a minimal structural intervention might prevent suicide jumps in a general hospital. Further work is needed to examine the effectiveness of minimal structural interventions in preventing suicide jumps. PMID:22862804

MASM, a Matrine Derivative, Offers Radioprotection by Modulating Lethal Total-Body Irradiation-Induced Multiple Signaling Pathways in Wistar Rats.

PubMed

Li, Jianzhong; Xu, Jing; Lu, Yiming; Qiu, Lei; Xu, Weiheng; Lu, Bin; Hu, Zhenlin; Chu, Zhiyong; Chai, Yifeng; Zhang, Junping

2016-05-17

Matrine is an alkaloid extracted from Sophora flavescens Ait and has many biological activities, such as anti-inflammatory, antitumor, anti-fibrosis, and immunosuppressive properties. In our previous studies, the matrine derivative MASM was synthesized and exhibited potent inhibitory activity against liver fibrosis. In this study, we mainly investigated its protection against lethal total-body irradiation (TBI) in rats. Administration of MASM reduced the radiation sickness characteristics and increased the 30-day survival of rats before or after lethal TBI. Ultrastructural observation illustrated that pretreatment of rats with MASM significantly attenuated the TBI-induced morphological changes in the different organs of irradiated rats. Gene expression profiles revealed that pretreatment with MASM had a dramatic effect on gene expression changes caused by TBI. Pretreatment with MASM prevented differential expression of 53% (765 genes) of 1445 differentially expressed genes induced by TBI. Pathway enrichment analysis indicated that these genes were mainly involved in a total of 21 pathways, such as metabolic pathways, pathways in cancer, and mitogen-activated protein kinase (MAPK) pathways. Our data indicated that pretreatment of rats with MASM modulated these pathways induced by TBI, suggesting that the pretreatment with MASM might provide the protective effects on lethal TBI mainly or partially through the modulation of these pathways, such as multiple MAPK pathways. Therefore, MASM has the potential to be used as an effective therapeutic or radioprotective agent to minimize irradiation damages and in combination with radiotherapy to improve the efficacy of cancer therapy.

Lethal and sublethal effects of seven insecticides on three beneficial insects in laboratory assays and field trials.

PubMed

Fernandes, Maria E S; Alves, Flávia M; Pereira, Renata C; Aquino, Leonardo A; Fernandes, Flávio L; Zanuncio, José C

2016-08-01

Lethal and sublethal effects of insecticides on target and non-target arthropods are a concern of pest management programs. Cycloneda sanguinea, Orius insidiosus and Chauliognathus flavipes are important biological control agents for aphids, whitefly, lepidopterus eggs, thrips and mites. All three test species were subjected to a toxicity study using the insecticides acephate, bifenthrin, chlorantraniliprole, chlorpyrifos, deltamethrin, imidacloprid, and thiamethoxam. Experiments were done in the lab and field. In the laboratory we evaluated the mortality and sublethal effects of the concentration that killed 20% of the population (LC20) on feeding, repellence and reproduction of the species tested. The lethal effects of these insecticides at the recommended doses was evaluated in the field. Concentration-response bioassays indicated chlorantraniliprole had the lowest toxicity, while chlorpyrifos and acephate were the most toxic. Test species exposed to filter paper surfaces treated with pyrethroids, neonicotinoids and organophosphates were repelled. On the other hand, test species were not repelled from surfaces treated with chlorantraniliprole. Chlorantraniliprole therefore seemed to be the least dangerous insecticide for these three beneficial arthropod test species. Copyright © 2016 Elsevier Ltd. All rights reserved.

Zn(2+)-dependence of the synergistic increase in rat thymocyte cell lethality caused by simultaneous application of 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) and H2O2.

PubMed

Saitoh, Shohei; Fukunaga, Eri; Ohtani, Hana; Oyama, Yasuo

2015-09-01

4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) is an antifouling agent that is an alternative to organotins such as tributyltin (TBT). Because DCOIT decreases catalase activity, it may increase the susceptibility of cells to oxidative stress. We examined the effects of DCOIT on rat thymocytes suffering from oxidative stress induced by H2O2. The simultaneous application of DCOIT and H2O2 induced a synergistic increase in cell lethality that was completely suppressed by chelating intracellular Zn(2+). Intracellular Zn(2+) concentration was increased by DCOIT at concentrations ranging from 0.1 μM to 3 μM. Although the increase in cell lethality produced by DCOIT alone was less than that produced by TBT alone, a synergistic increase was not induced by the combination of TBT and H2O2. Therefore, these results suggest that DCOIT increases vulnerability to oxidative stress and is more cytotoxic than TBT when oxidative stress is induced by H2O2. Copyright © 2014 Elsevier Ltd. All rights reserved.

Toxicity and bioconcentration evaluation of RDX and HMX using sheepshead minnows in water exposures.

PubMed

Lotufo, Guilherme R; Gibson, Alfreda B; Yoo, J Leslie

2010-10-01

Lethal effects of the explosives RDX and HMX were assessed using ten-day water exposures to juvenile sheepshead minnows (Cyprinodon variegatus). For RDX, maximum mortality occurred during the first two days of exposure with a 10-d median lethal concentration (LC50) of 9.9 mg L(-1). The RDX 10-d median lethal residue (LR50) was 9.6 mg kg(-1) (34.9 μmol kg(-1)) wet weight (ww), the first RDX critical body residue reported for fish. Previous investigations reported that RDX body residues in marine amphipods up to 96 μmol kg(-1) ww and in marine mussels up to 86 μmol kg(-1) ww failed to result in significant mortality. The highest HMX concentration tested, corresponding to its apparent solubility limit in seawater (2.0 mg L(-1)), and the associated mean body residue (3 mg kg(-1) or 14 μmol kg(-1) ww) resulted in no significant mortality for exposed minnows. The mean 10-d bioconcentration factors for RDX (0.6-0.9 L kg(-1)) and HMX (0.3-1.6 L kg(-1)) were typically lower than 1, reflecting the low bioaccumulative potential for these compounds. Published by Elsevier Inc.

Assessment of Caudal Fin Clips as a Non-lethal Technique for Predicting Muscle Tissue Mercury Concentrations in Largeouth Bass

EPA Science Inventory

The statistical relationship between total mercury (Hg) concentration in clips from the caudal fin and muscle tissue of largemouth bass (Micropterus salmoides) from 26 freshwater sites in Rhode Island, USA was developed and evaluated to determine the utility of fin clip analysis ...

Acaricidal activity of petroleum ether extract of neem (Azadirachta indica) oil and its four fractions separated by column chromatography against Sarcoptes scabiei var. cuniculi larvae in vitro.

PubMed

Deng, Yunxia; Shi, Dongxia; Yin, Zhongqiong; Guo, Jianhong; Jia, Renyong; Xu, Jiao; Song, Xu; Lv, Cheng; Fan, Qiaojia; Liang, Xiaoxia; Shi, Fei; Ye, Gang; Zhang, Wei

2012-04-01

The petroleum ether extract of neem oil and its four fractions separated by column chromatography was diluted at different concentrations with liquid paraffin. The acaricidal bioassay was conducted using a dipping method. The results indicated that the median lethal concentration (LC50) of the petroleum ether extract (at the concentration of 500.0ml/l) was 70.9ml/l, 24h after treatment. At concentrations of 500.0, 250.0, 125.0, 62.5 and 31.2ml/l, the median lethal times (LT50) of the petroleum ether extract were 8.7, 8.8, 10.8, 11.5 and 13.1h, respectively. Thin-layer chromatography (TLC) showed that the petroleum ether extract of neem oil separated into four fractions (F1-F4). Acaricidal activity of 68.3% and 100.0% in the F2 and F4 was confirmed. These results suggest that petroleum ether extracts of neem oil and its four fractions possess useful acaricidal activity in vitro. Copyright © 2012 Elsevier Inc. All rights reserved.

Cholinergic alterations by exposure to pesticides used in control vector: Guppies fish (Poecilia reticulta) as biological model.

PubMed

Toledo-Ibarra, G A; Rodríguez-Sánchez, E J; Ventura-Ramón, H G; Díaz-Resendiz, K J G; Girón-Pérez, M I

2018-02-01

Spinosad and temephos are two of the most used pesticides in Mexico for the control of vector causing disease such as dengue, chikungunya and Zika. The aim of this study was to compare the neurotoxic effects of these two pesticides using guppy fish (Poecilia reticulata) as a model organism. Guppies were exposed for 7 and 21 days to technical grade temephos and spinosad at 1.0 and 0.07 g/L, respectively, (10 and 0.5 mg/L of active substance; concentrations recommended by the Ministery of Health of the State (Secretaría de Salud de Nayarit (SSN) Mexico)). Subsequently, acetylcholinesterase activity (AChE) and acetylcholine concentrations (ACh) in muscle tissue were determined. Temephos exposure decreased AChE activity and increased ACh concentration, whereas exposure to spinosad only increased ACh concentration. Though cholinergic alterations were more severe in fish exposed to temephos, both pesticides were equally lethal during the first seven days after exposure. Nonetheless, temephos was more lethal after 21 days.

Nanoformulation of poly(ethylene glycol) polymerized organic insect repellent by PIT emulsification method and its application for Japanese encephalitis vector control.

PubMed

Balaji, A P B; Mishra, Prabhakar; Suresh Kumar, R S; Mukherjee, Amitava; Chandrasekaran, Natarajan

2015-04-01

The utilization of increased dosage of insect repellents to overcome mosquito resistance has raised environmental concerns globally. In accord to this, we have formulated an efficacious, water-dispersive, nanometric formulation of a poor water-soluble insect repellent, diethylphenylacetamide (DEPA) by poly(ethylene glycol) (PEG) polymerization followed by PIT emulsification method. The critical micelle concentration of PEG in the spontaneously emulsified conventional DEPA droplets was determined, based on the droplets physical stability. Subjecting them to PIT emulsification yielded monodispersed polymeric nanomicelles of DEPA (Nano DEPA) with hydrodynamic mean diameter of 153.74 nm. The high-resolution scanning and transmission electron microscopic studies revealed the characteristic core-shell structure of micelle. The comparative efficacy of Bulk DEPA and Nano DEPA was evaluated by larvicidal and WHO cone bioassay against the Japanese encephalitis vector Culex tritaeniorhynchus. The median lethal concentrations (48 h) for 3rd instars C. tritaeniorhynchus larvae were found to be 0.416 mg/L for Bulk DEPA and 0.052 mg/L for Nano DEPA, respectively. The median knockdown concentrations (60 min) for the two to three-day-old, sucrose-fed, female adult mosquitoes were 5.372% (v/v) and 3.471% (v/v) for Bulk and Nano DEPA, respectively. Further investigation by histopathological and biochemical studies propound that Nano DEPA exerted better bioefficacy as comparative to its bulk form even at minimal exposure concentrations. Hence, Nano DEPA will serve as an effective alternate in controlling the vector expansion with reduced dosage. Copyright © 2015 Elsevier B.V. All rights reserved.

Retinal metabolic events in preconditioning light stress as revealed by wide-spectrum targeted metabolomics.

PubMed

de la Barca, Juan Manuel Chao; Huang, Nuan-Ting; Jiao, Haihan; Tessier, Lydie; Gadras, Cédric; Simard, Gilles; Natoli, Riccardo; Tcherkez, Guillaume; Reynier, Pascal; Valter, Krisztina

2017-01-01

Light is the primary stimulus for vision, but may also cause damage to the retina. Pre-exposing the retina to sub-lethal amount of light (or preconditioning) improves chances for retinal cells to survive acute damaging light stress. This study aims at exploring the changes in retinal metabolome after mild light stress and identifying mechanisms that may be involved in preconditioning. Retinas from 12 rats exposed to mild light stress (1000 lux × for 12 h) and 12 controls were collected one and seven days after light stress (LS). One retina was used for targeted metabolomics analysis using the Biocrates p180 kit while the fellow retina was used for histological and immunohistochemistry analysis. Immunohistochemistry confirmed that in this experiment, a mild LS with retinal immune response and minimal photoreceptor loss occurred. Compared to controls, LS induced an increased concentration in phosphatidylcholines. The concentration in some amino acids and biogenic amines, particularly those related to the nitric oxide pathway (like asymmetric dimethylarginine (ADMA), arginine and citrulline) also increased 1 day after LS. 7 days after LS, the concentration in two sphingomyelins and phenylethylamine was found to be higher. We further found that in controls, retina metabolome was different between males and females: male retinas had an increased concentration in tyrosine, acetyl-ornithine, phosphatidylcholines and (acyl)-carnitines. Besides retinal sexual metabolic dimorphism, this study shows that preconditioning is mostly associated with re-organisation of lipid metabolism and changes in amino acid composition, likely reflecting the involvement of arginine-dependent NO signalling.

Lethal mobilization of DDT by cowbirds

USGS Publications Warehouse

Van Velzen, A.C.; Stiles, W.B.; Stickel, L.F.

1972-01-01

This study is an experimental demonstration of lethal mobilization of DDT by brown-headed cowbirds (Molothrus ater) and the effects of food deprivation on the distribution and loss of DDT, DDD, and DDE. The principal experimental group consisted of 20 birds fed a dietary dosage of 100 ppm of DDT for 13 days. After 2 days of full rations of untreated food, they were subjected to food restriction. Food was reduced to 43 percent of normal. Seven of the 20 birds died within 4 days. No birds died in the three control groups, treated as follows: ( 1 ) 20 birds fed 100 ppm DDT for 13 days and full rations of untreated food thereafter, (2) 20 birds fed only untreated food but subjected to food restriction, and (3) 20 birds fed full rations of untreated food throughout. In a pilot study, birds were fed 100, 200, or 300 ppm of DDT and subjected to two periods of food restriction, the first of these immediately after dosage ceased and the second 4 months later. DDT-dosed birds from all dosage levels died in each period of food restriction. Before the weight loss that accompanied food restriction, the brains of DDT-dosed birds had concentrations of DDT and DDD that were far below the lethal range. Concentrations increased rapidly to lethal levels. In these birds, DDT in carcasses decreased while DDD increased. DDT-dosed birds that died during food restriction lost 16 percent of their total body burden of DDT + DDD + DDE, 21 percent of their weight, and 81 percent of their fat. The DDT-dosed birds that were subjected to food restriction but survived lost a significantly greater proportion of their body burden of residues than similarly dosed birds not subjected to weight loss. Brain levels of DDT and DDD in birds that died during food restriction soon after dosage did not differ significantly from brain levels of birds that died in a period of food restriction 4 months after dosage. Concentrations of DDE were significantly higher in the latter group, although they were lower than concentrations considered to be lethal. In contrast, carcass levels of DDT and DDD were significantly lower, and DDE was only slightly higher, in the birds that died in the second period of food restriction. It is concluded that stored DDT residues present a hazard to birds, which utilize stored fat during periods of stress due to reproduction, cold weather, disease, injury, limited food supply, or migration.

Acute toxicity of fipronil to the stingless bee Scaptotrigona postica Latreille.

PubMed

Jacob, Cynthia Renata Oliveira; Soares, Hellen Maria; Carvalho, Stephan Malfitano; Nocelli, Roberta Cornélio Ferreira; Malaspina, Osmar

2013-01-01

Fipronil is an insecticide widely used to control a great number of pests, thus the aim of this study was to determine the lethal dose and lethal concentration (LD(50) and LC(50)) of this insecticide to the stingless bees Scaptotrigona postica Latreille, 1807. The LD(50) and LC(50) values obtained after 24 h of exposition were of 0.54 ng a.i./bee and 0.24 ng a.i./μL diet, respectively. These values were considered highly toxic to stingless bees.

Impacts of road deicing salts on the early-life growth and development of a stream salmonid: Salt type matters.

PubMed

Hintz, William D; Relyea, Rick A

2017-04-01

The use of road deicing salts in regions that experience cold winters is increasing the salinity of freshwater ecosystems, which threatens freshwater resources. Yet, the impacts of environmentally relevant road salt concentrations on freshwater organisms are not well understood, particularly in stream ecosystems where salinization is most severe. We tested the impacts of deicing salts-sodium chloride (NaCl), magnesium chloride (MgCl 2 ), and calcium chloride (CaCl 2 )-on the growth and development of newly hatched rainbow trout (Oncorhynchus mykiss). We exposed rainbow trout to a wide range of environmentally relevant chloride concentrations (25, 230, 860, 1500, and 3000 mg Cl -  L -1 ) over an ecologically relevant time period (25 d). We found that the deicing salts studied had distinct effects. MgCl 2 did not affect rainbow trout growth at any concentration. NaCl had no effects at the lowest three concentrations, but rainbow trout length was reduced by 9% and mass by 27% at 3000 mg Cl -  L -1 . CaCl 2 affected rainbow trout growth at 860 mg Cl -  L -1 (5% reduced length; 16% reduced mass) and these effects became larger at higher concentrations (11% reduced length; 31% reduced mass). None of the deicing salts affected rainbow trout development. At sub-lethal and environmentally relevant concentrations, our results do not support the paradigm that MgCl 2 is the most toxic deicing salt to fish, perhaps due to hydration effects on the Mg 2+ cation. Our results do suggest different pathways for lethal and sub-lethal effects of road salts. Scaled to the population level, the reduced growth caused by NaCl and CaCl 2 at critical early-life stages has the potential to negatively affect salmonid recruitment and population dynamics. Our findings have implications for environmental policy and management strategies that aim to reduce the impacts of salinization on freshwater organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of Potential Sublethal Effects of Various Insecticides on Key Biological Traits of The Tobacco Whitefly, Bemisia tabaci

PubMed Central

He, Yuxian; Zhao, Jianwei; Zheng, Yu; Weng, Qiyong; Biondi, Antonio; Desneux, Nicolas; Wu, Kongming

2013-01-01

The tobacco whitefly Bemisia tabaci is one of the most devastating pests worldwide. Current management of B. tabaci relies upon the frequent applications of insecticides. In addition to direct mortality by typical acute toxicity (lethal effect), insecticides may also impair various key biological traits of the exposed insects through physiological and behavioral sublethal effects. Identifying and characterizing such effects could be crucial for understanding the global effects of insecticides on the pest and therefore for optimizing its management in the crops. We assessed the effects of sublethal and low-lethal concentrations of four widely used insecticides on the fecundity, honeydew excretion and feeding behavior of B. tabaci adults. The probing activity of the whiteflies feeding on treated cotton seedlings was recorded by an Electrical Penetration Graph (EPG). The results showed that imidacloprid and bifenthrin caused a reduction in phloem feeding even at sublethal concentrations. In addition, the honeydew excretions and fecundity levels of adults feeding on leaf discs treated with these concentrations were significantly lower than the untreated ones. While, sublethal concentrations of chlorpyrifos and carbosulfan did not affect feeding behavior, honeydew excretion and fecundity of the whitefly. We demonstrated an antifeedant effect of the imidacloprid and bifenthrin on B. tabaci, whereas behavioral changes in adults feeding on leaves treated with chlorpyrifos and carbosulfan were more likely caused by the direct effects of the insecticides on the insects' nervous system itself. Our results show that aside from the lethal effect, the sublethal concentration of imidacloprid and bifenthrin impairs the phloem feeding, i.e. the most important feeding trait in a plant protection perspective. Indeed, this antifeedant property would give these insecticides potential to control insect pests indirectly. Therefore, the behavioral effects of sublethal concentrations of imidacloprid and bifenthrin may play an important role in the control of whitefly pests by increasing the toxicity persistence in treated crops. PMID:23494876

Effects of Petrol Exposure on Glucose, Liver and Muscle glycogen levels in the Common African toad Bufo regularis.

PubMed

Isehunwa, G O; Yusuf, I O; Alada, A Ar

2017-03-06

This study investigated the effects of exposure to petrol on blood glucose, liver and muscle glycogen levels in the common African toad Bufo regularis. A total of 126 adult toads of either sex weighing between 70-100g were used for this study. The experiment was divided into three phases. The phase 1 experiment the acute toxicity test consisted of animals divided into six groups of 10 toads per group and were exposed to water (H2O), H2O + Tween 80, 2ml/l, 3ml/l, 5ml/l, and 10ml/l of petrol respectively for 96 hours using the static renewal bioassay system. In the Phase 2 experiment, the animals were exposed to H2O, H2O + Tween 80, 0.14ml/l, 0.3ml/l, 0.6ml/l, and 1.13ml/l of petrol respectively for 3 days; while in phase 3 experiment they were exposed to petrol solutions for 14 days. After the various exposures, the blood glucose, liver and muscle glycogen contents were determined using standard methods. The results of the study showed that the median lethal concentration of petrol (96 hours LC50) was 4.5ml/l and sub-lethal concentration of petrol caused mortality of animals. Exposure to petrol solutions for 3 days had no significant effect on blood glucose level of the animals but caused significant decrease in the liver and muscle glycogen levels at high concentrations. In the animals exposed to petrol solutions for 14 days, there was a significant increase in glucose levels and significant reduction in liver and muscle glycogen levels at high concentrations when compared with the control. The results show that sub-lethal concentrations of petrol can cause mortality of animals, hyperglycemia and reduction in liver and muscle glycogen levels. The effects of petrol exposure on carbohydrate metabolism depend on the concentration and duration of exposure.

Sub-lethal oxidative stress induces lysosome biogenesis via a lysosomal membrane permeabilization-cathepsin-caspase 3-transcription factor EB-dependent pathway.

PubMed

Leow, San Min; Chua, Shu Xian Serene; Venkatachalam, Gireedhar; Shen, Liang; Luo, Le; Clement, Marie-Veronique

2017-03-07

Here we provide evidence to link sub-lethal oxidative stress to lysosome biogenesis. Exposure of cells to sub-lethal concentrations of exogenously added hydrogen peroxide resulted in cytosol to nuclear translocation of the Transcription Factor EB (TFEB), the master controller of lysosome biogenesis and function. Nuclear translocation of TFEB was dependent upon the activation of a cathepsin-caspase 3 signaling pathway, downstream of lysosomal membrane permeabilization and accompanied by a significant increase in lysosome numbers as well as induction of TFEB-dependent lysosome-associated genes expression such as Ctsl, Lamp2 and its spliced variant Lamp2a, Neu1and Ctsb and Sqstm1 and Atg9b. The effects of sub-lethal oxidative stress on lysosomal gene expression and biogenesis were rescued upon gene silencing of caspase 3 and TFEB. Notably, caspase 3 activation was not associated with phenotypic hallmarks of apoptosis, evidenced by the absence of caspase 3 substrate cleavage, such as PARP, Lamin A/C or gelsolin. Taken together, these data demonstrate for the first time an unexpected and non-canonical role of a cathepsin-caspase 3 axis in the nuclear translocation of TFEB leading to lysosome biogenesis under conditions of sub-lethal oxidative stress.

Development of a pH/alkalinity treatment model for applications of the lampricide TFM to streams tributary to the Great Lakes

USGS Publications Warehouse

Bills, Terry D.; Boogaard, Michael A.; Johnson, David A.; Brege, Dorance C.; Scholefield, Ronald J.; Westman, R. Wayne; Stephens, Brian E.

2003-01-01

It has long been known that the toxicity of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) is influenced by chemical and physical properties of water. As the pH, conductivity, and alkalinity of water increase, greater concentrations of TFM are required to kill sea lamprey (Petromyzon marinus) larvae. Consequently, the concentration of TFM required for effective treatment varies among streams. Brown trout (Salmo trutta) and sea lamprey larvae were exposed to a series of TFM concentrations in a continuous-flow diluter for 12 h. Twenty five exposures were conducted at various water alkalinities and pHs that treatment personnel encounter during lampricide treatments. Survival/mortality data were analyzed for lampricide concentrations that produced 50 and 99.9% mortality (LC50 and LC99.9) for sea lamprey larvae and 25 and 50% mortality (LC25 and LC50) for brown trout. Linear regression analyses were performed for each set of tests for each selected alkalinity by comparing the 12-h post exposure LC99.9 sea lamprey data and LC25 brown trout data at each pH. Mortality data from on-site toxicity tests conducted by lampricide control personnel were compared to predicted values from the pH/alkalinity prediction model. Of the 31 tests examined, 27 resulted in the LC100s (lowest TFM concentration where 100% mortality of sea lamprey was observed after 12 h of exposure) falling within 0.2 mg/L of the predicted sea lamprey minimum lethal (LC99.9) range. The pH/alkalinity prediction model provides managers with an operational tool that reduces the amount of TFM required for effective treatment while minimizing the impact on non-target organisms.

The use of bacteria for detecting toxic effects of pollutants in soil and water

NASA Astrophysics Data System (ADS)

Obiakor, Maximilian; Wilson, Susan; Tighe, Matthew; Pereg, Lily

2017-04-01

Microbial abundance and diversity are essential for sustaining soil structure and function and have been strongly linked to human health and wellbeing. Antimony (Sb) in the environment can present an ecological hazard and depending on concentration can be lethal. The toxic effects of Sb(III) and Sb(V) on the model soil bacterium Azospirillum brasilense Sp7 were assessed in exposure-dose-response assays and water samples from an Sb contaminated creek were analyzed for bacterial mortality. In both cases, Sb(III) and Sb(V) greatly affected the survival of A. brasilense Sp7 cells. The Sb(III) had a greater toxic effect than Sb(V) at all concentrations tested. Critical concentrations of Sb also caused variant colonies to appear, indicating both acute and sub-lethal effects, which were dose and time dependent. This work demonstrates the usefulness of A. brasilense as an indicator species to detect harmful effects of an environmental pollutant of emerging concern.

Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives.

PubMed

Melo, Antonio Diego Brandão; Amaral, Amanda Figueiredo; Schaefer, Gustavo; Luciano, Fernando Bittencourt; de Andrade, Carla; Costa, Leandro Batista; Rostagno, Marcos Horácio

2015-10-01

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.

Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives

PubMed Central

Melo, Antonio Diego Brandão; Amaral, Amanda Figueiredo; Schaefer, Gustavo; Luciano, Fernando Bittencourt; de Andrade, Carla; Costa, Leandro Batista; Rostagno, Marcos Horácio

2015-01-01

The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils. PMID:26424908

Lethal and sub-lethal effects of cyproconazole on freshwater organisms: a case study with Chironomus riparius and Dugesia tigrina.

PubMed

Saraiva, Althiéris S; Sarmento, Renato A; Golovko, Oksana; Randak, Tomas; Pestana, João L T; Soares, Amadeu M V M

2018-04-01

The fungicide cyproconazole (CPZ) inhibits the biosynthesis of ergosterol, an essential sterol component in fungal cell membrane and can also affect non-target organisms by its inhibitory effects on P450 monooxygenases. The predicted environmental concentration of CPZ is up to 49.05 μg/L and 145.89 μg/kg in surface waters and sediments, respectively, and information about CPZ toxicity towards non-target aquatic organisms is still limited. This study aimed to address the lack of ecotoxicological data for CPZ, and thus, an evaluation of the lethal and sub-lethal effects of CPZ was performed using two freshwater invertebrates (the midge Chironomus riparius and the planarian Dugesia tigrina). The estimated CPZ 48 h LC 50 (95% CI) was 17.46 mg/L for C. riparius and 47.38 mg/L for D. tigrina. The emergence time (EmT 50 ) of C. riparius was delayed by CPZ exposure from 0.76 mg/L. On the other hand, planarians showed higher tolerance to CPZ exposure. Sub-lethal effects of CPZ on planarians included reductions in locomotion (1.8 mg/L), delayed photoreceptors regeneration (from 0.45 mg/L), and feeding inhibition (5.6 mg/L). Our results confirm the moderate toxicity of CPZ towards aquatic invertebrates but sub-lethal effects observed also suggest potential chronic effects of CPZ with consequences for population dynamics.

Toxicity of sediments from a mangrove forest patch in an urban area in Pernambuco (Brazil).

PubMed

Oliveira, D D; Souza-Santos, L P; Silva, H K P; Macedo, S J

2014-06-01

Industrial and urban residues are discharged every day to the rivers and may arrive at the mangrove forest and prejudice the quality of the environment and the organisms present there. The mangrove forest patch studied is encircled by an urban area of the city of Recife (Brazil) that has approximate 1.5 million inhabitants and is one of the most industrialized centers in Northeast Brazil. The aim of this study was to assess the quality of the sediments of this mangrove patch in terms of metal contamination and ecotoxicology. Samples of surface sediment were collected in six stations for toxicological tests and trace metal determination (Cr, Zn, Mn, Fe, Cu, Pb, Co and Ni), in July and August, 2006 (rainy season); and in January and February 2007 (dry season). Toxicity tests with solid-phase sediments were carried out with the copepod Tisbe biminiensis in order to observe lethal and sub-lethal endpoints and correlate them with chemical data. In June, there were no observed lethal effect, but two stations presented sub-lethal effects. In January, lethal effect occurred in three stations and sub-lethal in one station. The levels for Zn and Cr were at higher levels than international proposed guidelines (NOAA). There was a negative significant correlation between the copepods׳ fecundity, and Zn and Cr concentrations. Therefore, the studied sediments can be considered to have potential toxic to benthos due to the high content of Zn and Cr. Copyright © 2014 Elsevier Inc. All rights reserved.

Assessment of metals exposure and sub-lethal effects in voles and small birds captured near the DeLong Mountain Regional Transportation System Road, Cape Krusenstern National Monument, Alaska, 2006

USGS Publications Warehouse

Brumbaugh, William G.; Mora, Miguel A.; May, Thomas W.

2008-01-01

Voles (n=6) and small ground-nesting birds (n=12) were live-captured near the DeLong Mountain Regional Transportation System haul road in Cape Krusenstern National Monument in northwest Alaska in 2006 to assess metals exposure and sub-lethal biological effects. Similar numbers of animals were captured from a reference site in southern Cape Krusenstern National Monument for comparison. Histopathological examination of selected organs, blood analysis, and analysis for aluminum, barium, cadmium, lead, and zinc concentrations in liver and blood samples were performed. Voles and small birds captured from near the haul road had about 20 times greater blood and liver lead concentrations and about 3 times greater cadmium concentrations when compared to those from the reference site. Barium and zinc tissue concentrations of animals collected from different sites were not remarkably different, and aluminum concentrations were below the reporting limits in most samples. There was no clear evidence of serious sub-lethal biological effects such as lesions in internal organs or DNA damage in blood in any of the animals. Accordingly, blood and liver lead concentrations in animals captured near the haul road generally were less than tissue concentration thresholds associated with serious biological effects reported from other studies; however, subtle effects resulting from lead exposure, such as the suppression of the activity of certain enzymes, cannot be ruled out for those animals nearest the haul road. Notably, liver lead concentrations of voles and small birds at the reference location were considerably less than those previously reported for similar animals at reference sites in other parts of the United States, Canada, and Europe. Results from this reconnaissance-level study indicate that voles and small birds inhabiting this area are not suffering serious biological effects as a result of metals exposure; however, continued monitoring of lead and other metals is recommended because of uncertainties noted and because biological effects thresholds might be approached if exposure levels were to increase.

The effect of lonidamine (LND) on radiation and thermal responses of human and rodent cell lines

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

Raaphorst, G.P.; Feeley, M.M.; Danjoux, C.E.

1991-03-01

Rodent and human cells were tested for response to Lonidamine (LND) (1-(2,4 dichlorobenzyl) 1-indazol-3-carboxylic acid) combined with radiation or hyperthermia. Lonidamine exposure before, during, and after irradiation caused varying degrees of inhibition of potentially lethal damage (PLD) repair which was cell line dependent. In human glioma, melanoma, squamous cell carcinoma, and fibroblasts, LND exposure did not inhibit or only partially inhibited repair of potentially lethal damage. LND up to 100 micrograms/ml produced only a low level of toxicity in these cells and only slightly inhibited glucose consumption at the maximum concentration. In human glioma cells, LND treatment alone did notmore » inhibit PLD repair, but when combined with hyperthermia treatment at moderate levels easily achievable in the clinic, there was complete inhibition of potentially lethal damage repair. These data suggest that LND effectiveness is cell type dependent. Combinations of LND, hyperthermia, and radiation may be effective in cancer therapy especially in tumors such as glioma in which repair of potentially lethal damage may be extensive.« less

Inactivation of CDK2 is synthetically lethal to MYCN over-expressing cancer cells

PubMed Central

Molenaar, Jan J.; Ebus, Marli E.; Geerts, Dirk; Koster, Jan; Lamers, Fieke; Valentijn, Linda J.; Westerhout, Ellen M.; Versteeg, Rogier; Caron, Huib N.

2009-01-01

Two genes have a synthetically lethal relationship when the silencing or inhibiting of 1 gene is only lethal in the context of a mutation or activation of the second gene. This situation offers an attractive therapeutic strategy, as inhibition of such a gene will only trigger cell death in tumor cells with an activated second oncogene but spare normal cells without activation of the second oncogene. Here we present evidence that CDK2 is synthetically lethal to neuroblastoma cells with MYCN amplification and over-expression. Neuroblastomas are childhood tumors with an often lethal outcome. Twenty percent of the tumors have MYCN amplification, and these tumors are ultimately refractory to any therapy. Targeted silencing of CDK2 by 3 RNA interference techniques induced apoptosis in MYCN-amplified neuroblastoma cell lines, but not in MYCN single copy cells. Silencing of MYCN abrogated this apoptotic response in MYCN-amplified cells. Inversely, silencing of CDK2 in MYCN single copy cells did not trigger apoptosis, unless a MYCN transgene was activated. The MYCN induced apoptosis after CDK2 silencing was accompanied by nuclear stabilization of P53, and mRNA profiling showed up-regulation of P53 target genes. Silencing of P53 rescued the cells from MYCN-driven apoptosis. The synthetic lethality of CDK2 silencing in MYCN activated neuroblastoma cells can also be triggered by inhibition of CDK2 with a small molecule drug. Treatment of neuroblastoma cells with roscovitine, a CDK inhibitor, at clinically achievable concentrations induced MYCN-dependent apoptosis. The synthetically lethal relationship between CDK2 and MYCN indicates CDK2 inhibitors as potential MYCN-selective cancer therapeutics. PMID:19525400

Successive Onset of Molecular, Cellular and Tissue-Specific Responses in Midgut Gland of Littorina littorea Exposed to Sub-Lethal Cadmium Concentrations

PubMed Central

Benito, Denis; Izagirre, Urtzi; Dallinger, Reinhard; Soto, Manu

2017-01-01

Cadmium (Cd) is one of the most harmful metals, being toxic to most animal species, including marine invertebrates. Among marine gastropods, the periwinkle (Littorina littorea) in particular can accumulate high amounts of Cd in its midgut gland. In this organ, the metal can elicit extensive cytological and tissue-specific alterations that may reach, depending on the intensity of Cd exposure, from reversible lesions to pathological cellular disruptions. At the same time, Littorina littorea expresses a Cd-specific metallothionein (MT) that, due to its molecular features, expectedly exerts a protective function against the adverse intracellular effects of this metal. The aim of the present study was, therefore, to assess the time course of MT induction in the periwinkle’s midgut gland on the one hand, and cellular and tissue-specific alterations in the digestive organ complex (midgut gland and digestive tract) on the other, upon exposure to sub-lethal Cd concentrations (0.25 and 1 mg Cd/L) over 21 days. Depending on the Cd concentrations applied, the beginning of alterations of the assessed parameters followed distinct concentration-dependent and time-dependent patterns, where the timeframe for the onset of the different response reactions became narrower at higher Cd concentrations compared to lower exposure concentrations. PMID:28829377

Quantification of the efficiency of treatment of Anopheles gambiae breeding sites with petroleum products by local communities in areas of insecticide resistance in the Republic of Benin

PubMed Central

Djouaka, Rousseau F; Bakare, Adekunle A; Bankole, Honore S; Doannio, Julien MC MC; Kossou, Hortense; Akogbeto, Martin C

2007-01-01

Background The emergence of Anopheles populations capable of withstanding lethal doses of insecticides has weakened the efficacy of most insecticide based strategies of vector control and, has highlighted the need for developing new insecticidal molecules or, improving the efficacy of existing insecticides or abandoning those to which resistance has emerged. The use of petroleum products (PP) against mosquito larvae had an immense success during early programmes of malaria control, but these compounds were abandoned and replaced in the 1950s by synthetic insecticides probably because of the high performances given by these new products. In the current context of vector resistance, it is important to elucidate the empirical use of PP by quantifying their efficiencies on resistant strains of Anopheles. Methods Larvae of Anopheles Ladji a local resistant strain were exposed to increasing concentrations of various PP (kerosene, petrol and engine oils) for 24 hours and the lethal activities recorded. The highest concentration (HiC) having no lethal activity (also referred as the NOEL or no effect level) and the lowest concentration (LoC100) yielding 100% mortality were rated for each PP on the Ladji strain. Prior to laboratory analysis, KAP studies were conducted in three traditional communities were insecticide resistance is clearly established to confirm the use of PP against mosquitoes. Results Laboratory analysis of petrol, kerosene and engine oils, clearly established their lethal activities on resistant strains of Anopheles larvae. Contrary to existing references, this research revealed that exposed larvae of Anopheles were mostly killed by direct contact toxicity and not by suffocation as indicated in some earlier reports. Conclusion This research could serve as scientific basis to backup the empirical utilisation of PP on mosquito larvae and to envisage possibilities of using PP in some traditional settings where Anopheles have developed resistance to currently used insecticides. PMID:17488523

Global Comparison of Warring Groups in 2002–2007: Fatalities from Targeting Civilians vs. Fighting Battles

PubMed Central

Hicks, Madelyn Hsiao-Rei; Lee, Uih Ran; Sundberg, Ralph; Spagat, Michael

2011-01-01

Background Warring groups that compete to dominate a civilian population confront contending behavioral options: target civilians or battle the enemy. We aimed to describe degrees to which combatant groups concentrated lethal behavior into intentionally targeting civilians as opposed to engaging in battle with opponents in contemporary armed conflict. Methodology/Principal Findings We identified all 226 formally organized state and non-state groups (i.e. actors) that engaged in lethal armed conflict during 2002–2007: 43 state and 183 non-state. We summed civilians killed by an actor's intentional targeting with civilians and combatants killed in battles in which the actor was involved for total fatalities associated with each actor, indicating overall scale of armed conflict. We used a Civilian Targeting Index (CTI), defined as the proportion of total fatalities caused by intentional targeting of civilians, to measure the concentration of lethal behavior into civilian targeting. We report actor-specific findings and four significant trends: 1.) 61% of all 226 actors (95% CI 55% to 67%) refrained from targeting civilians. 2.) Logistic regression showed actors were more likely to have targeted civilians if conflict duration was three or more years rather than one year. 3.) In the 88 actors that targeted civilians, multiple regressions showed an inverse correlation between CTI values and the total number of fatalities. Conflict duration of three or more years was associated with lower CTI values than conflict duration of one year. 4.) When conflict scale and duration were accounted for, state and non-state actors did not differ. We describe civilian targeting by actors in prolonged conflict. We discuss comparable patterns found in nature and interdisciplinary research. Conclusions/Significance Most warring groups in 2002–2007 did not target civilians. Warring groups that targeted civilians in small-scale, brief conflict concentrated more lethal behavior into targeting civilians, and less into battles, than groups in larger-scale, longer conflict. PMID:21915272

Lethal and sub-lethal effects of elevated CO2 concentrations on marine benthic invertebrates and fish.

PubMed

Lee, Changkeun; Hong, Seongjin; Kwon, Bong-Oh; Lee, Jung-Ho; Ryu, Jongseong; Park, Young-Gyu; Kang, Seong-Gil; Khim, Jong Seong

2016-08-01

Concern about leakage of carbon dioxide (CO2) from deep-sea storage in geological reservoirs is increasing because of its possible adverse effects on marine organisms locally or at nearby coastal areas both in sediment and water column. In the present study, we examined how elevated CO2 affects various intertidal epibenthic (benthic copepod), intertidal endobenthic (Manila clam and Venus clam), sub-tidal benthic (brittle starfish), and free-living (marine medaka) organisms in areas expected to be impacted by leakage. Acute lethal and sub-lethal effects were detected in the adult stage of all test organisms exposed to varying concentrations of CO2, due to the associated decline in pH (8.3 to 5.2) during 96-h exposure. However, intertidal organisms (such as benthic copepods and clams) showed remarkable resistance to elevated CO2, with the Venus clam being the most tolerant (LpH50 = 5.45). Sub-tidal species (such as brittle starfish [LpH50 = 6.16] and marine medaka [LpH50 = 5.91]) were more sensitive to elevated CO2 compared to intertidal species, possibly because they have fewer defensive capabilities. Of note, the exposure duration might regulate the degree of acute sub-lethal effects, as evidenced by the Venus clam, which showed a time-dependent effect to elevated CO2. Finally, copper was chosen as a model toxic element to find out the synergistic or antagonistic effects between ocean acidification and metal pollution. Combination of CO2 and Cu exposure enhances the adverse effects to organisms, generally supporting a synergistic effect scenario. Overall, the significant variation in the degree to which CO2 adversely affected organisms (viz., working range and strength) was clearly observed, supporting the general concept of species-dependent effects of elevated CO2.

Pathology of carbon monoxide poisoning in two cats.

PubMed

Sobhakumari, Arya; Poppenga, Robert H; Pesavento, J Brad; Uzal, Francisco A

2018-03-05

Carbon monoxide (CO), a common cause of poisoning in human beings has also been implicated in the death of animals. Though there are multiple studies on CO poisoning and relevant lethal blood COHb concentrations in humans, there are no reliable reports of diagnostic lethal carboxyhemoglobin percentage of saturation (COHb%) in cats. Additionally, due to shared housing environments, exposures to companion animals can be a surrogate for lethal exposures in human beings and provide valuable information in concurrent forensic investigations. Two adult Singapura brown ticked cats were submitted to the California Animal Health and Food Safety Laboratory (CAHFS) for necropsy and diagnostic work-up. These animals were found dead along with their two deceased owners. Similar lesions were observed in both cats. At necropsy, gross lesions consisted of multifocal, large, irregular, bright red spots on the skin of the abdomen and the inner surface of ear pinnae, bright red muscles and blood. The carcasses, and tissues fixed in formalin retained the bright red discoloration for up to two weeks. Microscopic lesions included diffuse pulmonary congestion and edema, and multifocal intense basophilia of cardiomyocytes mostly affecting whole fibers or occasionally a portion of the fiber. Based on the clinical history,gross and microscopic changes, cyanide or carbon monoxide poisoning was suspected. Blood samples analyzed for carbon monoxide showed 57 and 41% carboxyhemoglobin COHb%. Muscle samples were negative for cyanide. There are no established reference values for lethal COHb concentration in cats. The COHb % values detected in this case which fell within the lethal range reported for other species, along with the gross lesions and unique histological findings in the heart suggest a helpful criteria for diagnosis of CO intoxication associated death in cats. This case demonstrates that since pets share the same environment as human beings and often are a part of their activities, they can be useful adjuncts in potential forensic investigations to help solve human cases.

Induction of high tolerance to artemisinin by sub-lethal administration: A new in vitro model of P. falciparum.

PubMed

De Lucia, Serena; Tsamesidis, Ioannis; Pau, Maria Carmina; Kesely, Kristina R; Pantaleo, Antonella; Turrini, Francesco

2018-01-01

Artemisinin resistance is a major threat to malaria control efforts. Resistance is characterized by an increase in the Plasmodium falciparum parasite clearance half-life following treatment with artemisinin-based combination therapies (ACTs) and an increase in the percentage of surviving parasites. The remarkably short blood half-life of artemisinin derivatives may contribute to drug-resistance, possibly through factors including sub-lethal plasma concentrations and inadequate exposure. Here we selected for a new strain of artemisinin resistant parasites, termed the artemisinin resistant strain 1 (ARS1), by treating P. falciparum Palo Alto (PA) cultures with sub-lethal concentrations of dihydroartemisinin (DHA). The resistance phenotype was maintained for over 1 year through monthly maintenance treatments with low doses of 2.5 nM DHA. There was a moderate increase in the DHA IC50 in ARS1 when compared with parental strain PA after 72 h of drug exposure (from 0.68 nM to 2 nM DHA). In addition, ARS1 survived treatment physiologically relevant DHA concentrations (700 nM) observed in patients. Furthermore, we confirmed a lack of cross-resistance against a panel of antimalarials commonly used as partner drugs in ACTs. Finally, ARS1 did not contain Pfk13 propeller domain mutations associated with ART resistance in the Greater Mekong Region. With a stable growth rate, ARS1 represents a valuable tool for the development of new antimalarial compounds and studies to further elucidate the mechanisms of ART resistance.

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

Herkovits, J.; Herkovits, F.D.; Perez-Coll

As a result of their aquatic embryonic and larval development, many species of amphibians are potentially affected by adverse environmental conditions. In this study the possibility of reducing the lethal effect of aluminum (ALC13, Mallinckrodt) in Bufo arenarum embryos by means of simultaneous zinc (ZnSO4) treatment is reported. The aluminum hazard was evaluated in a 7 day renewal toxicity testing study conducted with batches of 10 individuals (by quadruplicate) in six concentrations of aluminum plus the control at 20 C. The pH of the experimental solutions were measured. The LC100 expressed as Al(3 +) mg/L at 24 and up tillmore » 168 hours of treatment were 0.9 (the pH of the solution was 6.2 while in control Holtfreter solution the pH was 6.8). Therefore, aluminum exert a lethal effect on amphibian embryos in concentrations which reduce only slightly the pH of the maintaining solution. The lethal effect of aluminum could be reduced 100% by means of simultaneous treatment with 2 mg Zn(2 +)/L. The results point out the high sensibility of the amphibian embryos to aluminum (LC100/24hs:0.9mg Al(3 +)/L) and therefore, episodic increases in dissolved aluminum, usually concomitant with surface water pH decreases, could produce very harmful effects during embryonic stages of amphibians. The noteworthy beneficial effect of zinc against the lethal effect of aluminum could be of practical value in reducing the harmful effects exerted by aluminum. The conspicuous Al-Zn antagonism points out the need of biological test systems for recording the integrated effects of substances released to the environment.« less

The genotoxic effects of the imidacloprid-based insecticide formulation Glacoxan Imida on Montevideo tree frog Hypsiboas pulchellus tadpoles (Anura, Hylidae).

PubMed

Pérez-Iglesias, J M; Ruiz de Arcaute, C; Nikoloff, N; Dury, L; Soloneski, S; Natale, G S; Larramendy, M L

2014-06-01

The neonicotinoid insecticide imidacloprid (IMI) affects the insect central nervous system and is successfully applied to control pests for a variety of agricultural crops. In the current study, acute toxicity and genotoxicity of the IMI-containing commercial formulation insecticide Glacoxan Imida (35 percent IMI) was evaluated on Hypsiboas pulchellus (Anura: Hylidae) tadpoles exposed under laboratory conditions. A lethal effect was evaluated as the end point for lethality, whereas micronucleus (MN) frequency and DNA single-strand breaks evaluated by the single cell gel electrophoresis (SCGE) assay were employed as end points for genotoxicity. Sublethal end points were assayed within the 12.5-37.5mg/L IMI concentration range. Experiments were performed on tadpoles at stage 36 (range, 35-37) according to the classification proposed by Gosner. Lethality studies revealed an LC50 96h value of 52.622mg/L IMI. Increased frequency of MNs was only observed when 25.0mg/L was assayed for 96h, whereas no other nuclear abnormalities were induced. Increase of the genetic damage index was observed at 48h of treatment within the 12.5-37.5mg/L concentration range, whereas an increased frequency of DNA damage was observed only in tadpoles treated with 37.5mg/L IMI for 96h. This study represents the first evidence of the acute lethal and genotoxic effects exerted by IMI on tadpoles of an amphibian species native to Argentina under laboratory conditions. Copyright © 2014 Elsevier Inc. All rights reserved.

Graphical determination of metal bioavailability to soil invertebrates utilizing the Langmuir sorption model

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

Donkin, S.G.

1997-09-01

A new method of performing soil toxicity tests with free-living nematodes exposed to several metals and soil types has been adapted to the Langmuir sorption model in an attempt at bridging the gap between physico-chemical and biological data gathered in the complex soil matrix. Pseudo-Langmuir sorption isotherms have been developed using nematode toxic responses (lethality, in this case) in place of measured solvated metal, in order to more accurately model bioavailability. This method allows the graphical determination of Langmuir coefficients describing maximum sorption capacities and sorption affinities of various metal-soil combinations in the context of real biological responses of indigenousmore » organisms. Results from nematode mortality tests with zinc, cadmium, copper, and lead in four soil types and water were used for isotherm construction. The level of agreement between these results and available literature data on metal sorption behavior in soils suggests that biologically relevant data may be successfully fitted to sorption models such as the Langmuir. This would allow for accurate prediction of soil contaminant concentrations which have minimal effect on indigenous invertebrates.« less

Problems associated with the use of immediately dangerous to life and health (IDLH) values for estimating the hazard of accidental chemical releases.

PubMed

Alexeeff, G V; Lipsett, M J; Kizer, K W

1989-11-01

The possibility of accidental industrial chemical releases has generated considerable recent attention. One area requiring research for emergency planning is the development of safe exposure concentrations for the public in the event of an inadvertent release. The United States Environmental Protection Agency (EPA) has established a list of extremely hazardous substances and suggested that the toxicity ranking for 92 hazardous materials could be based on the "immediately dangerous to life or health" (IDLH) values developed by the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). Eighty-four compounds with IDLH values for which published toxicologic data were available were reviewed to assess the appropriateness of applying such values to accidental release situations. When compared with 30-min animal median lethal concentrations (LC50s), 18 of the IDLHs reviewed were in the same range as lethal levels for animals. For 45 compounds the IDLH values were comparable to concentrations producing severe toxic effects (specifically, unconsciousness, incapacitation, or intolerable irritation). Where available, emergency planning guidelines for the military were compared to IDLHs, and in all 31 cases, the IDLHs exceeded the military exposure guidelines. Twenty compounds also were found to pose a potential cancer risk according to common regulatory guidelines, even under the assumption of a single, 30-min exposure at the IDLH concentration. In addition, the high degree of variability (four orders of magnitude) in the relationship of IDLH values to outcomes of lethality or severe toxicity suggests that the use of IDLH values as emergency planning guidelines for accidental releases is questionable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation and Preadaptation of Salmonella enterica to Bile

PubMed Central

Hernández, Sara B.; Cota, Ignacio; Ducret, Adrien; Aussel, Laurent; Casadesús, Josep

2012-01-01

Bile possesses antibacterial activity because bile salts disrupt membranes, denature proteins, and damage DNA. This study describes mechanisms employed by the bacterium Salmonella enterica to survive bile. Sublethal concentrations of the bile salt sodium deoxycholate (DOC) adapt Salmonella to survive lethal concentrations of bile. Adaptation seems to be associated to multiple changes in gene expression, which include upregulation of the RpoS-dependent general stress response and other stress responses. The crucial role of the general stress response in adaptation to bile is supported by the observation that RpoS− mutants are bile-sensitive. While adaptation to bile involves a response by the bacterial population, individual cells can become bile-resistant without adaptation: plating of a non-adapted S. enterica culture on medium containing a lethal concentration of bile yields bile-resistant colonies at frequencies between 10−6 and 10−7 per cell and generation. Fluctuation analysis indicates that such colonies derive from bile-resistant cells present in the previous culture. A fraction of such isolates are stable, indicating that bile resistance can be acquired by mutation. Full genome sequencing of bile-resistant mutants shows that alteration of the lipopolysaccharide transport machinery is a frequent cause of mutational bile resistance. However, selection on lethal concentrations of bile also provides bile-resistant isolates that are not mutants. We propose that such isolates derive from rare cells whose physiological state permitted survival upon encountering bile. This view is supported by single cell analysis of gene expression using a microscope fluidic system: batch cultures of Salmonella contain cells that activate stress response genes in the absence of DOC. This phenomenon underscores the existence of phenotypic heterogeneity in clonal populations of bacteria and may illustrate the adaptive value of gene expression fluctuations. PMID:22275872

The Vitamin B12 Analog Cobinamide Is an Effective Antidote for Oral Cyanide Poisoning.

PubMed

Lee, Jangwoen; Mahon, Sari B; Mukai, David; Burney, Tanya; Katebian, Behdod S; Chan, Adriano; Bebarta, Vikhyat S; Yoon, David; Boss, Gerry R; Brenner, Matthew

2016-12-01

Cyanide is a major chemical threat, and cyanide ingestion carries a higher risk for a supra-lethal dose exposure compared to inhalation but provides an opportunity for effective treatment due to a longer treatment window and a gastrointestinal cyanide reservoir that could be neutralized prior to systemic absorption. We hypothesized that orally administered cobinamide may function as a high-binding affinity scavenger and that gastric alkalinization would reduce cyanide absorption and concurrently increase cobinamide binding, further enhancing antidote effectiveness. Thirty New Zealand white rabbits were divided into five groups and were given a lethal dose of oral cyanide poisoning (50 mg). The survival time of animals was monitored with oral cyanide alone, oral cyanide with gastric alkalinization with oral sodium bicarbonate buffer (500 mg), and in combination with either aquohydroxocobinamide or dinitrocobinamide (250 mM). Red blood cell cyanide concentration, plasma cobinamide, and thiocyanate concentrations were measured from blood samples. In cyanide ingested animals, oral sodium bicarbonate alone significantly prolonged survival time to 20.3 ± 8.6 min compared to 10.5 ± 4.3 min in saline-treated controls, but did not lead to overall survival. Aquohydroxocobinamide and dinitrocobinamide increased survival time to 64 ± 41 (p < 0.05) and 75 ± 16.4 min (p < 0.001), respectively. Compared to aquohydroxocobinamide, dinitrocobinamide showed greater systemic absorption and reduced blood pressure. Dinitrocobinamide also markedly increased the red blood cell cyanide concentration. Under all conditions, the plasma thiocyanate concentration gradually increased with time. This study demonstrates a promising new approach to treat high-dose cyanide ingestion, with gastric alkalinization alone and in combination with oral cobinamide for treating a supra-lethal dose of orally administered cyanide in rabbits.

Effects of a fire-retardant chemical to fathead minnows in experimental streams

USGS Publications Warehouse

Calfee, R.D.; Little, E.E.

2003-01-01

Background. Each year millions of liters of fire-retardant chemicals are applied to wildfires across the nation. Recent laboratory studies with long-term fire-retardant chemicals indicate a significant photoenhanced toxicity of products containing sodium ferrocyanide corrosion inhibitors. Our objective of this study was to determine the toxicity of fire-retardant chemicals to fathead minnows during exposure in experimental outdoor streams. Methods. Stream tests were conducted to determine the potential toxicity of a pulse of exposure as might occur when fire retardant chemical is rinsed from the watershed by rainfall. Two artificial 55-meter experimental streams were dosed with different concentrations of Fire-Trol?? GTS-R, or uncontaminated for a control. Replicate groups of fathead minnows were added to screened containers (10 fish per container) and exposed to retardant chemicals in the recirculating flow of the stream for up to 6 hours. Results and Discussion. Under field conditions toxicity of GTS-R only occurred in the presence of sunlight. When GTS-R was tested on sunny days, 100% mortality occurred. However, when tested during heavily overcast conditions, no mortality occurred. Conclusions. Lethal concentrations of cyanide were measured when GTS-R with YPS exposures were conducted under sunny conditions, but not under cloudy conditions, indicating that a minimum UV level is necessary to induce toxicity as well as the release of cyanide from YPS. The toxicity observed with GTS-R was likely associated with lethal concentrations of cyanide. Rainwater runoff following applications of this fire-retardant at the recommended rate could result in lethal concentrations in small ponds and streams receiving limited water flow under sunny conditions. Recommendations and Outlook. In addition to avoiding application to aquatic habitats, it is important to consider characteristics of the treated site including soil binding affinity and erosive properties.

Living on next to nothing: tree seedlings can survive weeks with very low carbohydrate concentrations.

PubMed

Weber, Raphael; Schwendener, Andrea; Schmid, Sandra; Lambert, Savoyane; Wiley, Erin; Landhäusser, Simon M; Hartmann, Henrik; Hoch, Günter

2018-04-01

The usage of nonstructural carbohydrates (NSCs) to indicate carbon (C) limitation in trees requires knowledge of the minimum tissue NSC concentrations at lethal C starvation, and the NSC dynamics during and after severe C limitation. We completely darkened and subsequently released seedlings of two deciduous and two evergreen temperate tree species for varying periods. NSCs were measured in all major organs, allowing assessment of whole-seedling NSC balances. NSCs decreased fast in darkness, but seedlings survived species-specific whole-seedling starch concentrations as low as 0.4-0.8% per dry matter (DM), and sugar (sucrose, glucose and fructose) concentrations as low as 0.5-2.0% DM. After re-illumination, the refilling of NSC pools began within 3 wk, while the resumption of growth was delayed or restricted. All seedlings had died after 12 wk of darkness, and starch and sugar concentrations in most tissues were lower than 1% DM. We conclude that under the applied conditions, tree seedlings can survive several weeks with very low NSC reserves probably also using alternative C sources like lipids, proteins or hemicelluloses; lethal C starvation cannot be assumed, if NSC concentrations are higher than the minimum concentrations found in surviving seedlings; and NSC reformation after re-illumination occurs preferentially over growth. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Estimation of effectiveness of three methods of feral cat population control by use of a simulation model.

PubMed

McCarthy, Robert J; Levine, Stephen H; Reed, J Michael

2013-08-15

To predict effectiveness of 3 interventional methods of population control for feral cat colonies. Population model. Estimates of vital data for feral cats. Data were gathered from the literature regarding the demography and mating behavior of feral cats. An individual-based stochastic simulation model was developed to evaluate the effectiveness of trap-neuter-release (TNR), lethal control, and trap-vasectomy-hysterectomy-release (TVHR) in decreasing the size of feral cat populations. TVHR outperformed both TNR and lethal control at all annual capture probabilities between 10% and 90%. Unless > 57% of cats were captured and neutered annually by TNR or removed by lethal control, there was minimal effect on population size. In contrast, with an annual capture rate of ≥ 35%, TVHR caused population size to decrease. An annual capture rate of 57% eliminated the modeled population in 4,000 days by use of TVHR, whereas > 82% was required for both TNR and lethal control. When the effect of fraction of adult cats neutered on kitten and young juvenile survival rate was included in the analysis, TNR performed progressively worse and could be counterproductive, such that population size increased, compared with no intervention at all. TVHR should be preferred over TNR for management of feral cats if decrease in population size is the goal. This model allowed for many factors related to the trapping program and cats to be varied and should be useful for determining the financial and person-effort commitments required to have a desired effect on a given feral cat population.

Smyd1 Facilitates Heart Development by Antagonizing Oxidative and ER Stress Responses

PubMed Central

Park, Chong Yon; Harriss, June; Pierce, Stephanie A.; Dekker, Joseph D.; Valenzuela, Nicolas; Srivastava, Deepak; Schwartz, Robert J.; Stewart, M. David; Tucker, Haley O.

2015-01-01

Smyd1/Bop is an evolutionary conserved histone methyltransferase previously shown by conventional knockout to be critical for embryonic heart development. To further explore the mechanism(s) in a cell autonomous context, we conditionally ablated Smyd1 in the first and second heart fields of mice using a knock-in (KI) Nkx2.5-cre driver. Robust deletion of floxed-Smyd1 in cardiomyocytes and the outflow tract (OFT) resulted in embryonic lethality at E9.5, truncation of the OFT and right ventricle, and additional defects consistent with impaired expansion and proliferation of the second heart field (SHF). Using a transgenic (Tg) Nkx2.5-cre driver previously shown to not delete in the SHF and OFT, early embryonic lethality was bypassed and both ventricular chambers were formed; however, reduced cardiomyocyte proliferation and other heart defects resulted in later embryonic death at E11.5-12.5. Proliferative impairment prior to both early and mid-gestational lethality was accompanied by dysregulation of transcripts critical for endoplasmic reticulum (ER) stress. Mid-gestational death was also associated with impairment of oxidative stress defense—a phenotype highly similar to the previously characterized knockout of the Smyd1-interacting transcription factor, skNAC. We describe a potential feedback mechanism in which the stress response factor Tribbles3/TRB3, when directly methylated by Smyd1, acts as a co-repressor of Smyd1-mediated transcription. Our findings suggest that Smyd1 is required for maintaining cardiomyocyte proliferation at minimally two different embryonic heart developmental stages, and its loss leads to linked stress responses that signal ensuing lethality. PMID:25803368

[Detection of the lethal process in plankton noctiluca by means of a forbidden transition of ESR of Mn2+ ion].

PubMed

Kamenev, S E; Kopvillem, U Kh; Pasynkov, A S; Sharipov, R Z

1981-01-01

A forbidden ESR line of Mn2+ that is connected with the penetration of Mn into the plancton organism and binding it to a marcomolecule is selected from the experiment. A method for saturating the plancton organism with paramagnetic ions is proposed. It is shown that the constant of the axial electric field in the spin hamiltonian of Mn2+ ion described the dynamics of a selforganizing system. It is tested that the lethal process in the plancton with paramagnetic ion enrichment originated from boson avalanche. Experiments are performed with plancton noctiluca which illustrate the occurrence of avalancheline lethal process in the case of paramagnetic ion enrichment with limiting concentration. The meaning of these results for the problems of oceanology and pollution-ocean inhabitants interaction in the case of paramagnetic ions is discussed.

Interactive lethal and mutagenic effects of ultraviolet light and bleomycin in yeast: synergism or antagonism?

PubMed

Lillo, O L; Severgnini, A A; Nunes, E M

1997-11-01

The mutagenic interactions of ultraviolet light and bleomycin in haploid populations of Saccharomyces cerevisiae were analyzed. Survival and mutation frequency as a function of different bleomycin concentrations after one conditioning dose of UV radiation were determined. Furthermore, corresponding interaction functions and sensitization factors were calculated. A synergistic interaction between UV light and bleomycin was shown for both lethal and mutagenic events when the cells were in nutrient broth during the treatments. Conversely, the interaction between UV light and bleomycin was antagonistic when the cells were in deionized water during the treatment. The magnitude of lethal and mutagenic interactions depends on dose, and thus presumably on the number of lesions. The observed interactions between UV light and bleomycin suggest that the mechanism that is most likely involved is the induction of repair systems with different error probabilities during the delay of cell division.

Enhancement of amphotericin B activity against Candida albicans by superoxide radical.

PubMed

Okamoto, Yuichi; Aoki, Shigeji; Mataga, Izumi

2004-07-01

This study aimed to examine the involvement of oxidative damage in amphotericin B (AmB) activity against Candida albicans using the superoxide (O2-) generator paraquat (PQ). The effects of PQ on AmB activities against growth, viability, membrane permeability and respiration were examined in a wild-type parent strain (K) and a respiration-deficient mutant (KRD-19) since PQ-induced superoxide generation depends on respiration. In the parent strain, the minimal inhibitory concentration (MIC) of AmB, 0.25 microg/ml, tested with a liquid culture was lowered to 0.025 microg/ml by 1 mM PQ. Such a PQ-induced decrease in the MIC value of AmB was minimal in the mutant. Similar PQ-induced enhancement of AmB activity toward the parent strain was also observed with growth on an agar medium. In viability tests, when candidal cells were exposed to AmB (0.1 microg/ml) for I h, the lethality of AmB was enhanced by 1 mM PQ only in the parent strain. Exogenous superoxide dismutase and catalase failed to diminish the enhancing effect of PQ on the growth inhibitory activity of AmB in the parent strain, suggesting an interaction between superoxide and AmB in candidal cells. The enhancement of AmB activity by PQ, observed preferentially in the wild-type strain, can be explained by extensive superoxide generation depending on respiration. These results suggest that oxidative damage induced by superoxide is involved in AmB activity against C. albicans.

Non-thermal plasma jet without electrical shock for biomedical applications

NASA Astrophysics Data System (ADS)

Baik, Ku Youn; Kang, Han Lim; Kim, Junseong; Park, Shin Young; Bang, Ji Yun; Uhm, Han S.; Choi, Eun Ha; Cho, Guangsup

2013-10-01

A plasma jet without an electrical shock was generated through a Y-shaped tube in which voltages with opposite phases were applied to a pair of tubes. The plasma plume generated at the intersection had a plasma potential of a 60-90 V and high concentrations of reactive species sufficient to induce a high level of lethality on gram-negative bacteria on a tissue mimic. The selective lethality of bacteria on an epithelial-cell-containing tissue mimic could be modulated using oxidant and antioxidant chemicals, thereby leading to the possibility of a shock-reduced plasma jet for biomedical applications.

The Identification of a Legionella pneumophila Toxin with in vivo Lethality

DTIC Science & Technology

1980-01-01

It lacked hydroxy fatty a similar extract, obtained from a newly acids , was minimally inhibited by treat- discovered, but genetically unrelated, ment...applied to the Molecular Weight Estimation column depending upon the individual acid supernatant preparation. There A Sephadex G-50 column (1.5 x...Table 1). Although 0.5 ml of the first peak readi- One-milligram amounts of protein ly kills mice within 18 hours, as much as from Legionella acid

A novel homozygous variant in SERPINH1 associated with a severe, lethal presentation of osteogenesis imperfecta with hydranencephaly.

PubMed

Marshall, Charlotte; Lopez, Jaime; Crookes, Laura; Pollitt, Rebecca C; Balasubramanian, Meena

2016-12-20

Osteogenesis imperfecta (OI) is a genetic disorder characterised by low bone mineral density resulting in fractures. 85-90% of patients with OI carry a variant in the type 1 collagen genes, COL1A1 and COL1A2, which follows an autosomal dominant pattern of inheritance. However, within the last two decades, there have been growing number of variants identified in genes that follow an autosomal recessive pattern of inheritance. Our proband is a child born in Mexico with multiple fractures of ribs, minimal calvarial mineralisation, platyspondyly, marked compression and deformed long bones. He also presented with significant hydranencephaly, requiring ventilatory support from birth, and died at 8days of age. A homozygous c.338_357delins22 variant in exon 2 of SERPINH1 was identified. This gene encodes heat shock protein 47, a collagen-specific chaperone which binds to the procollagen triple helix and is responsible for collagen stabilisation in the endoplasmic reticulum. There is minimal literature on the mechanism of action for variants in SERPINH1 resulting in osteogenesis imperfecta. Here we discuss this rare, previously unreported variant, and expand on the phenotypic presentation of this novel variant resulting in a severe, lethal phenotype of OI in association with hydranencephaly. Copyright © 2016 Elsevier B.V. All rights reserved.

Experimental West Nile Virus Infection in Rabbits: An Alternative Model for Studying Induction of Disease and Virus Control

PubMed Central

Suen, Willy W.; Uddin, Muhammad J.; Wang, Wenqi; Brown, Vienna; Adney, Danielle R.; Broad, Nicole; Prow, Natalie A.; Bowen, Richard A.; Hall, Roy A.; Bielefeldt-Ohmann, Helle

2015-01-01

The economic impact of non-lethal human and equine West Nile virus (WNV) disease is substantial, since it is the most common presentation of the infection. Experimental infection with virulent WNV strains in the mouse and hamster models frequently results in severe neural infection and moderate to high mortality, both of which are not representative features of most human and equine infections. We have established a rabbit model for investigating pathogenesis and immune response of non-lethal WNV infection. Two species of rabbits, New Zealand White (Oryctolagus cuniculus) and North American cottontail (Sylvilagus sp.), were experimentally infected with virulent WNV and Murray Valley encephalitis virus strains. Infected rabbits exhibited a consistently resistant phenotype, with evidence of low viremia, minimal-absent neural infection, mild-moderate neuropathology, and the lack of mortality, even though productive virus replication occurred in the draining lymph node. The kinetics of anti-WNV neutralizing antibody response was comparable to that commonly seen in infected horses and humans. This may be explained by the early IFNα/β and/or γ response evident in the draining popliteal lymph node. Given this similarity to the human and equine disease, immunocompetent rabbits are, therefore, a valuable animal model for investigating various aspects of non-lethal WNV infections. PMID:26184326

Development and worldwide use of non-lethal, and minimal population-level impact, protocols for the isolation of amphibian chytrid fungi.

PubMed

Fisher, Matthew C; Ghosh, Pria; Shelton, Jennifer M G; Bates, Kieran; Brookes, Lola; Wierzbicki, Claudia; Rosa, Gonçalo M; Farrer, Rhys A; Aanensen, David M; Alvarado-Rybak, Mario; Bataille, Arnaud; Berger, Lee; Böll, Susanne; Bosch, Jaime; Clare, Frances C; A Courtois, Elodie; Crottini, Angelica; Cunningham, Andrew A; Doherty-Bone, Thomas M; Gebresenbet, Fikirte; Gower, David J; Höglund, Jacob; James, Timothy Y; Jenkinson, Thomas S; Kosch, Tiffany A; Lambertini, Carolina; Laurila, Anssi; Lin, Chun-Fu; Loyau, Adeline; Martel, An; Meurling, Sara; Miaud, Claude; Minting, Pete; Ndriantsoa, Serge; O'Hanlon, Simon J; Pasmans, Frank; Rakotonanahary, Tsanta; Rabemananjara, Falitiana C E; Ribeiro, Luisa P; Schmeller, Dirk S; Schmidt, Benedikt R; Skerratt, Lee; Smith, Freya; Soto-Azat, Claudio; Tessa, Giulia; Toledo, Luís Felipe; Valenzuela-Sánchez, Andrés; Verster, Ruhan; Vörös, Judit; Waldman, Bruce; Webb, Rebecca J; Weldon, Che; Wombwell, Emma; Zamudio, Kelly R; Longcore, Joyce E; Garner, Trenton W J

2018-05-17

Parasitic chytrid fungi have emerged as a significant threat to amphibian species worldwide, necessitating the development of techniques to isolate these pathogens into culture for research purposes. However, early methods of isolating chytrids from their hosts relied on killing amphibians. We modified a pre-existing protocol for isolating chytrids from infected animals to use toe clips and biopsies from toe webbing rather than euthanizing hosts, and distributed the protocol to researchers as part of the BiodivERsA project RACE; here called the RML protocol. In tandem, we developed a lethal procedure for isolating chytrids from tadpole mouthparts. Reviewing a database of use a decade after their inception, we find that these methods have been applied across 5 continents, 23 countries and in 62 amphibian species. Isolation of chytrids by the non-lethal RML protocol occured in 18% of attempts with 207 fungal isolates and three species of chytrid being recovered. Isolation of chytrids from tadpoles occured in 43% of attempts with 334 fungal isolates of one species (Batrachochytrium dendrobatidis) being recovered. Together, these methods have resulted in a significant reduction and refinement of our use of threatened amphibian species and have improved our ability to work with this group of emerging pathogens.

Phenotypic characterization of spontaneously mutated rats showing lethal dwarfism and epilepsy.

PubMed

Suzuki, Hiroetsu; Takenaka, Motoo; Suzuki, Katsushi

2007-08-01

We have characterized the phenotype of spontaneously mutated rats, found during experimental inbreeding in a closed colony of Wistar Imamichi rats. Mutant rats showed severe dwarfism, short lifespan (early postnatal lethality), and high incidence of epileptic seizures. Mutant rats showed growth retardation after 3 d of age, and at 21 d their weight was about 56% that of normal rats. Most mutant rats died without reaching maturity, and 95% of the mutant rats had an ataxic gait. About 34% of the dwarf rats experienced epileptic seizures, most of which started as 'wild running' convulsions, progressing to generalized tonic-clonic convulsions. At age 28 d, the relative weight of the testes was significantly lower, and the relative weight of the brain was significantly higher, in mutant than in normal rats. Histologically, increased apoptotic germ cells, lack of spermatocytes, and immature Leydig cells were found in the mutant testes, and extracellular vacuoles of various sizes were present in the hippocampus and amygdala of the mutant brain. Mutant rats had significantly increased concentrations of plasma urea nitrogen, creatinine, and inorganic phosphate, as well as decreased concentrations of plasma growth hormone. Hereditary analysis showed that the defects were inherited as a single recessive trait. We have named the hypothetically mutated gene as lde (lethal dwarfism with epilepsy).

In vitro lethal photosensitization of S. mutans using methylene blue and toluidine blue O as photosensitizers.

PubMed

Araújo, Patrícia V; Teixeira, Karina I R; Lanza, Lincoln D; Cortes, Maria E; Poletto, Luiz T A

2009-01-01

The purpose of this in vitro study was to evaluate the antimicrobial effect of photodynamic therapy on Streptococcus mutans (A TCC 25175) suspensions, using a red laser for one minute in combination with toluidine blue O (TBO) or methylene blue (MB). Both photosensitizers were used in three concentrations (25, 10 and 5 mg/L). The activity ofphotosensitizers and laser irradiation were tested separately on the bacteria, as well as the irradiation of this light source in the presence of the TBO or MB. These groups were compared to a control group, in which the microorganism did not receive any treatment. The activity of both TBO and MB or laser irradiation, alone, were not able to reduce the number of S. mutans. In the groups of lethal photosensitization, a bacterial reduction of 70% for TBO and 73% for MB was observed when these photosensitizers were used at 25 mg/L and a reduction of 48% was observed for MB at 5mg/L. In other concentrations there were no significant differences in comparison to the control group. Both the TBO and the MB at 25 mg/L associated with a red laser had an excellent potential for use in PDT in lethal sensitization of S. mutans.

Estradiol uptake, toxicity, metabolism, and adverse effects on cadmium-treated amphibian embryos.

PubMed Central

Fridman, Osvaldo; Corró, Lucrecia; Herkovits, Jorge

2004-01-01

The exposure of Bufo arenarum embryos to 25 micromol/L 17beta-estradiol (E2) resulted in 100% lethality within 48 hr, whereas 10 micromol//L E2 was the no observed effect concentration value for short-term chronic (7 days) exposure. The toxicity profile curves show that lethal effects were proportional to the E2 concentration and the time of exposure. The E2 uptake resulted in 20.1 ng E2/mg embryo at 8 hr posttreatment, but 67.3% of this value was achieved during the first 30 min of incubation with this estrogen. Regarding metabolism, the embryos synthesize estrone (E1) from E2 by means of 17beta-hydroxysteroid dehydrogenase. Simultaneous treatments of Bufo arenarum embryos with 1 mg/L Cd2+ and 0.1, 1, or 10 micromol/L E2 enhanced the lethality exerted by cadmium in 76.7, 80, and 83.3% of embryos, respectively. The results indicate that estrogenic endocrine disruptors could have an adverse effect on amphibian embryos and enhance the toxic effect of Cd on amphibian embryos. This study points to the possibility of using the AMPHITOX test as a screening method for potential endocrine disruption as well as the combined effects of chemical mixtures. PMID:15175173

The combination of the entomopathogenic fungus Metarhizium anisopliae with the insecticide Imidacloprid increases virulence against the dengue vector Aedes aegypti (Diptera: Culicidae).

PubMed

Paula, Adriano R; Carolino, Aline T; Paula, Cátia O; Samuels, Richard I

2011-01-25

Dengue fever transmitted by the mosquito Aedes aegypti, is one of the most rapidly spreading insect borne diseases, stimulating the search for alternatives to current control measures. The dengue vector A. aegypti has received less attention than anophelene species, although more than 2.5 billion people are at risk of infection worldwide. Entomopathogenic fungi are emerging as potential candidates for the control of mosquitoes. Here we continue our studies on the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae against adult A. aegypti females. With the aim of further reducing mean survival times of A. aegypti exposed to fungus impregnated surfaces, a sub-lethal concentration of the neonicotinoid insecticide Imidacloprid (IMI) was added to fungal suspensions. A sub-lethal concentration of IMI that did not significantly alter the daily survival rates or mean survival percentages of mosquitoes was identified to be 0.1 ppm. This sub-lethal concentration was combined with M. anisopliae conidia (1 × 10(9) conidia mL(-1)). Both the combined treatment and the conidia alone were able to reduce the survival of A. aegypti compared with untreated or IMI treated mosquitoes. Importantly, mosquito survival following exposure to the combined treatment for 6 and 12 hrs was significantly reduced when compared with mosquitoes exposed to conidia alone. This is the first time that a combination of an insecticide and an entomopathogenic fungus has been tested against A. aegypti. Firstly, the study showed the potential of IMI as an alternative to the currently employed pyrethroid adulticides. Secondly, as an alternative to applications of high concentrations of chemical insecticides, we suggest that adult A. aegypti could be controlled by surface application of entomopathogenic fungi and that the efficiency of these fungi could be increased by combining the fungi with ultra-low concentrations of insecticides, resulting in higher mortality following relatively short exposure times.

The combination of the entomopathogenic fungus Metarhizium anisopliae with the insecticide Imidacloprid increases virulence against the dengue vector Aedes aegypti (Diptera: Culicidae)

PubMed Central

2011-01-01

Background Dengue fever transmitted by the mosquito Aedes aegypti, is one of the most rapidly spreading insect borne diseases, stimulating the search for alternatives to current control measures. The dengue vector A. aegypti has received less attention than anophelene species, although more than 2.5 billion people are at risk of infection worldwide. Entomopathogenic fungi are emerging as potential candidates for the control of mosquitoes. Here we continue our studies on the pathogenicity of the entomopathogenic fungus Metarhizium anisopliae against adult A. aegypti females. With the aim of further reducing mean survival times of A. aegypti exposed to fungus impregnated surfaces, a sub-lethal concentration of the neonicotinoid insecticide Imidacloprid (IMI) was added to fungal suspensions. Results A sub-lethal concentration of IMI that did not significantly alter the daily survival rates or mean survival percentages of mosquitoes was identified to be 0.1 ppm. This sub-lethal concentration was combined with M. anisopliae conidia (1 × 109 conidia mL-1). Both the combined treatment and the conidia alone were able to reduce the survival of A. aegypti compared with untreated or IMI treated mosquitoes. Importantly, mosquito survival following exposure to the combined treatment for 6 and 12 hrs was significantly reduced when compared with mosquitoes exposed to conidia alone. Conclusions This is the first time that a combination of an insecticide and an entomopathogenic fungus has been tested against A. aegypti. Firstly, the study showed the potential of IMI as an alternative to the currently employed pyrethroid adulticides. Secondly, as an alternative to applications of high concentrations of chemical insecticides, we suggest that adult A. aegypti could be controlled by surface application of entomopathogenic fungi and that the efficiency of these fungi could be increased by combining the fungi with ultra-low concentrations of insecticides, resulting in higher mortality following relatively short exposure times. PMID:21266078

Toxicity and fate of two munitions constituents in spiked sediment exposures with the marine amphipod Eohaustorius estuarius.

PubMed

Rosen, Gunther; Lotufo, Guilherme R

2005-11-01

The lethal toxicity of the explosive compounds 14C-labeled 2,4,6-trinitrotoluene (TNT) and nonradiolabeled hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the estuarine amphipod Eohaustorius estuarius was investigated in 10-d spiked sediment exposures. The 10-d median lethal concentration (LC50) was determined using the sum molar initial concentration of TNT, aminodinitrotoluenes (ADNTs), and diaminonitrotoluenes (DANTs), as determined by high-performance liquid chromatography (HPLC), and collectively referred to as HPLC-TNT*. Despite expectations of higher toxicity in sandy sediment (Yaquina Bay [YB], OR, USA) compared to relatively fine-grained sediment (San Diego Bay [SDB], CA, USA), LC50 values were similar: 159 and 125 micromol/kg, for YB and SDB sediments, respectively. When expressed as the sum of TNT and all its degradation products (14C-TNT*), LC50s were approximately two times the corresponding LC50s determined by HPLC. The HPLC-TNT* fraction likely corresponds to the most bioavailable and toxic transformation products. The concentrations of 14C-TNT* in tissues were substantially higher than those for HPLC-TNT*, suggesting that compounds other than TNT and its major aminated transformation products were prevalent. Critical body residues were similar for exposures to SDB (11.7 micromol/kg) and YB sediments (39.4 micromol/kg), despite marked differences in the nature of compounds available for uptake in the exposure media. The critical body residues for E. estuarius are lower than those reported for other aquatic invertebrates (83-172 micromol/kg). Unlike observations for TNT, RDX was only loosely associated with SDB sediment, with near complete recovery of the parent compound by chemical analysis. Exposure to RDX did not result in significant mortality even at the highest measured sediment concentration of 10,800 micromol/kg dry weight, nor tissue concentrations as high as 96 micromol/kg wet weight. The lack of RDX lethal effects in this study is consistent with results reported for other invertebrate species.

Homologous stress adaptation, antibiotic resistance, and biofilm forming ability of Salmonella enterica serovar Heidelberg (ATCC8326) on different food-contact surfaces following exposure to sub-lethal chlorine concentrations

USDA-ARS?s Scientific Manuscript database

Salmonella enterica serovar Heidelberg (American Type Culture Collection; ATCC 8326) was examined for the ability to adapt to the homologous stress of chlorine through exposure to increasing chlorine concentrations (25 ppm daily increments) in tryptic soy broth (TSB). The tested strain exhibited an ...

Predicting adult fish acute lethality with the zebrafish embryo: relevance of test duration, endpoints, compound properties, and exposure concentration analysis.

PubMed

Knöbel, Melanie; Busser, Frans J M; Rico-Rico, Angeles; Kramer, Nynke I; Hermens, Joop L M; Hafner, Christoph; Tanneberger, Katrin; Schirmer, Kristin; Scholz, Stefan

2012-09-04

The zebrafish embryo toxicity test has been proposed as an alternative for the acute fish toxicity test, which is required by various regulations for environmental risk assessment of chemicals. We investigated the reliability of the embryo test by probing organic industrial chemicals with a wide range of physicochemical properties, toxicities, and modes of toxic action. Moreover, the relevance of using measured versus nominal (intended) exposure concentrations, inclusion of sublethal endpoints, and different exposure durations for the comparability with reported fish acute toxicity was explored. Our results confirm a very strong correlation of zebrafish embryo to fish acute toxicity. When toxicity values were calculated based on measured exposure concentrations, the slope of the type II regression line was 1 and nearly passed through the origin (1 to 1 correlation). Measured concentrations also explained several apparent outliers. Neither prolonged exposure (up to 120 h) nor consideration of sublethal effects led to a reduced number of outliers. Yet, two types of compounds were less lethal to embryos than to adult fish: a neurotoxic compound acting via sodium channels (permethrin) and a compound requiring metabolic activation (allyl alcohol).

Sub-lethal exposure of cockroaches to boric acid pesticide contributes to increased Bla g 2 excretion.

PubMed

Zhang, Y C; Perzanowski, M S; Chew, G L

2005-07-01

Several epidemiology studies have found an increase in the major cockroach allergen Bla g 2 with reported pesticide use. Our aim was to investigate the effect on the excretion of Bla g 1 and Bla g 2 allergens by cockroaches exposed to sub-lethal doses of the pesticides, boric acid and hydramethylnon gel. German cockroaches in separate colonies were fed either boric acid or hydramethylnon gel at concentrations of 0.2, 0.1 and 0.01% in their water supply over a 2 week period. Ten colonies were exposed to each treatment concentration. Bla g 1 and Bla g 2 in fecal pellets were measured by ELISA. Cockroaches exposed to boric acid excreted fecal pellets with significantly higher concentrations of Bla g 2 (35,400 U/g) than did controls (12,700 U/g) (P = 0.001). Bla g 1 concentrations were not significantly different. There was no difference in either Bla g 1 or Bla g 2 concentrations between cockroaches that ingested hydramethylnon gel and those in the controls colonies. The application of boric acid, a common pesticide, appears to paradoxically increase the production of Bla g 2, a major allergen, by the surviving cockroaches. This may have important implications in avoidance strategies.

Sublethal and hormesis effects of imidacloprid on the soybean aphid Aphis glycines.

PubMed

Qu, Yanyan; Xiao, Da; Li, Jinyu; Chen, Zhou; Biondi, Antonio; Desneux, Nicolas; Gao, Xiwu; Song, Dunlun

2015-04-01

The soybean aphid, Aphis glycines Matsumura, is a major pest in soybean crop. Current management of this pest relies mainly on insecticides applications, and the neonicotinoid imidacloprid has been proposed as an effective insecticide to control A. glycines in soybean field. Imidacloprid at lethal concentrations not only exerts acute toxicity to A. glycines, but also cause various biological changes when aphids are chronically exposed to lower concentrations. In this study, we assessed the effects of a low-lethal (0.20 mg L(-1)) and two sublethal (0.05 and 0.10 mg L(-1)) imidacloprid concentrations on various A. glycines life history traits. Aphid exposure to 0.20 mg L(-1) imidacloprid caused slower juvenile development, shorter reproductive period, and reduced adult longevity, fecundity and total lifespan. Stimulatory effects, i.e. hormesis, on reproduction and immature development duration were observed in aphids exposed to the lower sublethal imidacloprid concentrations. Consequently, the net reproduction rate (R 0) was significantly higher than in the control aphids. These findings stress the importance of the actual imidacloprid concentration in its toxicological properties on A. glycines. Therefore, our results would be useful for assessing the overall effects of imidacloprid on A. glycines and for optimizing integrated pest management programs targeting this pest.

Using a Lethality Index to Assess Susceptibility of Tribolium confusum and Oryzaephilus surinamensis to Insecticides

PubMed Central

Vlontzos, George; Arthur, Frank H.

2015-01-01

We evaluated knockdown caused by four insecticides: alpha-cypermethrin, chlorfenapyr, pirimiphos-methyl and fipronil against adults of Tribolium confusum Jacquelin Duval, the confused flour beetle and Oryzaephilus surinamensis (L.), the sawtoothed grain beetle. Bioassays were conducted on concrete and metal surfaces. Adults of the tested species were exposed on both surfaces treated with the above insecticides at two doses (low and high). Knockdown assessment was done after 15, 30 and 60 min of adult exposure in the treated surfaces. Also, after 1, 3, 5, 7 and 14 d of exposure, a lethality index was calculated with an equation resulting to values from 0 to 100, where 100 indicated complete mortality and 0 complete survival. We also developed a lethality index by ranking each adult on each surface from 0 to 4, 0: adults moved normally, 1: adults were knocked down, but were able to walk for short intervals, 2: adults were knocked down and unable to walk, but with visible movement of antennae etc., 3: adults were knocked down, with very minimal movement of the tarsi and the antennae and 4: adults were dead (no movement). Knockdown of adults immediately after exposure (15–60 min) was higher for pirimiphos-methyl followed by alpha-cypermethrin, for both dose rates tested and species, but only on the metal surface. The lethality index was nearly 100 for all insecticides after 5d of exposure for O. surinamensis, while for T. confusum the adult lethality index was considerably lower for alpha-cypermethrin, suggesting that that recovery from knockdown occurred. Chlorfenapyr was the only insecticide that was more effective on concrete than on metal, while the reverse was noted for the other three insecticides. These results show that knockdown has different levels, which can be used as indicators of insect mortality or recovery. PMID:26560316

Physiologic Conditions Affect Toxicity of Ingested Industrial Fluoride

PubMed Central

Sauerheber, Richard

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings. PMID:23840230

Physiologic conditions affect toxicity of ingested industrial fluoride.

PubMed

Sauerheber, Richard

2013-01-01

The effects of calcium ion and broad pH ranges on free fluoride ion aqueous concentrations were measured directly and computed theoretically. Solubility calculations indicate that blood fluoride concentrations that occur in lethal poisonings would decrease calcium below prevailing levels. Acute lethal poisoning and also many of the chronic effects of fluoride involve alterations in the chemical activity of calcium by the fluoride ion. Natural calcium fluoride with low solubility and toxicity from ingestion is distinct from fully soluble toxic industrial fluorides. The toxicity of fluoride is determined by environmental conditions and the positive cations present. At a pH typical of gastric juice, fluoride is largely protonated as hydrofluoric acid HF. Industrial fluoride ingested from treated water enters saliva at levels too low to affect dental caries. Blood levels during lifelong consumption can harm heart, bone, brain, and even developing teeth enamel. The widespread policy known as water fluoridation is discussed in light of these findings.

Acute toxic responses of the freshwater planarian, Dugesia dorotocephala, to methylmercury

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

Best, J.B.; Morita, M.; Ragin, J.

1981-07-01

Toxic responses of planaria to various aquatic habitat concentrations of methylmercury chloride (MMC) were investigated. One hundred percent lethality occurred within 5 h in 2 ppM MMC, 24 h in 1 ppM MMC, and 5 days in 0.5 ppM MMC. No deaths occurred in 0.2 ppM MMC over a 10 day period, however, non-lethal toxic responses were observed. Varying degrees of head resorption, progressing caudally from the snout were observed. With continuing exposure, partial head regeneration and recovery toward more normal appearance occurred by 10 days. Teratogenic effects were observed in surgical decapitation experiments. Head regeneration was retarded in 0.1more » and 0.2 ppM MMC. Malformations, visible lesions, or gross behavioral abnormalities were produced by 2 week exposure of planaria to concentrations of 20 ppB MMC or lower. (RJC)« less

Lethal and sublethal effects of azadirachtin on the bumblebee Bombus terrestris (Hymenoptera: Apidae).

PubMed

Barbosa, Wagner Faria; De Meyer, Laurens; Guedes, Raul Narciso C; Smagghe, Guy

2015-01-01

Azadirachtin is a biorational insecticide commonly reported as selective to a range of beneficial insects. Nonetheless, only few studies have been carried out with pollinators, usually emphasizing the honeybee Apis mellifera and neglecting other important pollinator species such as the bumblebee Bombus terrestris. Here, lethal and sublethal effects of azadirachtin were studied on B. terrestris via oral exposure in the laboratory to bring out the potential risks of the compound to this important pollinator. The compound was tested at different concentrations above and below the maximum concentration that is used in the field (32 mg L(-1)). As most important results, azadirachtin repelled bumblebee workers in a concentration-dependent manner. The median repellence concentration (RC50) was estimated as 504 mg L(-1). Microcolonies chronically exposed to azadirachtin via treated sugar water during 11 weeks in the laboratory exhibited a high mortality ranging from 32 to 100 % with a range of concentrations between 3.2 and 320 mg L(-1). Moreover, no reproduction was scored when concentrations were higher than 3.2 mg L(-1). At 3.2 mg L(-1), azadirachtin significantly inhibited the egg-laying and, consequently, the production of drones during 6 weeks. Ovarian length decreased with the increase of the azadirachtin concentration. When azadirachtin was tested under an experimental setup in the laboratory where bumblebees need to forage for food, the sublethal effects were stronger as the numbers of drones were reduced already with a concentration of 0.64 mg L(-1). Besides, a negative correlation was found between the body mass of male offspring and azadirachtin concentration. In conclusion, our results as performed in the laboratory demonstrated that azadirachtin can affect B. terrestris with a range of sublethal effects. Taking into account that sublethal effects are as important as lethal effects for the development and survival of the colonies of B. terrestris, this study confirms the need to test compounds on their safety, especially when they have to perform complex tasks such as foraging. The latter agrees with the recent European Food Safety Authority guidelines to assess 'potentially deleterious' compounds for sublethal effects on behavior.

Determination of tylosins A, B, C and D in bee larvae by liquid chromatography coupled to ion trap-tandem mass spectrometry.

PubMed

Bernal, J; Martín, Ma T; Toribio, L; Martín-Hernández, R; Higes, M; Bernal, J L; Nozal, M J

2011-06-01

A LC-MS/MS method has been developed to simultaneously quantify tylosins A, B, C and D in bee larvae, compounds currently used to treat one of the most lethal diseases affecting honey bees around the world, American Foulbrood (AFB). The influence of different aqueous media, temperature and light exposure on the stability of these four compounds was studied. The analytes were extracted from bee larvae with methanol and chromatographic separation was achieved on a Luna C(18) (150 × 4.6 mm i.d.) using a ternary gradient composed of a diluted formic acid, methanol and acetonitrile mobile phase. To facilitate sampling, bee larvae were initially dried at 60°C for 4h and afterwards, they were diluted to avoid problems of pressure. MSD-Ion Trap detection was employed with electrospray ionization (ESI). The calibration curves were linear over a wide range of concentrations and the method was validated as sensitive, precise and accurate within the limits of quantification (LOQ, 1.4-4.0 ng/g). The validated method was successfully employed to study bee larvae in field tests of bee hives treated with two formulations containing tylosin. In both cases it was evident that the minimal inhibitory concentration (MIC) had been reached. Copyright © 2011 Elsevier B.V. All rights reserved.

Selenium concentrations in the razorback sucker (Xyrauchen texanus): Substitution of non-lethal muscle plugs for muscle tissue in contaminant assessment

USGS Publications Warehouse

Waddell, B.; May, T.

1995-01-01

A single muscle plug was collected from each of 25 live razorback suckers inhabiting the Colorado River basin and analyzed for selenium by instrumental neutron activation. Eight fish from Ashley Creek and three from Razorback Bar exhibited selenium concentrations exceeding 8 μg/g, a level associated with reproductive failure in fish. Concentrations of selenium in eggs and milt were significantly correlated with selenium concentrations in muscle plugs and together indicate a possible explanation for the decline of this species in the Colorado River basin. Muscle plugs (<50mg) and muscle tissue (20 g) were collected from dorsal, anterior, and posterior areas of common carp, flannelmouth sucker, and an archived razorback sucker and analyzed for selenium. Concentrations of selenium in muscle plugs were significantly correlated with selenium concentrations in muscle tissue from the same location and fish (r=0.97). Coefficients of variation for selenium concentrations in each fish were <6.5% for muscle tissue, but ranged from 1.5 to 32.4% for muscle plugs. Increased variation in muscle plugs was attributed to lower selenium concentrations found in the anterior muscle plugs of flannelmouth suckers. Mean selenium concentrations in muscle plugs and tissue from dorsal and posterior areas and muscle tissue from the anterior area were not significantly different. The non-lethal collection of a muscle plug from dorsal and posterior areas of the razorback sucker and other fish species may provide an accurate assessment of selenium concentrations that exist in adjacent muscle tissue.

Acute toxicity of arsenic and oxidative stress responses in the embryonic development of the common South American toad Rhinella arenarum.

PubMed

Mardirosian, Mariana Noelia; Lascano, Cecilia Inés; Ferrari, Ana; Bongiovanni, Guillermina Azucena; Venturino, Andrés

2015-05-01

Arsenic (As), a natural element of ecological relevance, is found in natural water sources throughout Argentina in concentrations between 0.01 mg/L and 15 mg/L. The autochthonous toad Rhinella arenarum was selected to study the acute toxicity of As and the biochemical responses elicited by the exposure to As in water during its embryonic development. The median lethal concentration (LC50) value averaged 24.3 mg/L As and remained constant along the embryonic development. However, As toxicity drastically decreased when embryos were exposed from heartbeat-stage on day 4 of development, suggesting the onset of detoxification mechanisms. Given the environmental concentrations of As in Argentina, there is a probability of exceeding lethal levels at 1% of sites. Arsenic at sublethal concentrations caused a significant decrease in the total antioxidant potential but generated an increase in endogenous glutathione (GSH) content and glutathione S-transferase (GST) activity. This protective response might prevent a deeper decline in the antioxidant system and further oxidative damage. Alternatively, it might be linked to As conjugation with GSH for its excretion. The authors conclude that toad embryos are more sensitive to As during early developmental stages and that relatively high concentrations of this toxic element are required to elicit mortality, but oxidative stress may be an adverse effect at sublethal concentrations. © 2014 SETAC.

Biochemical and genotoxic response of naphthalene to fingerlings of milkfish Chanos chanos.

PubMed

Palanikumar, L; Kumaraguru, A K; Ramakritinan, C M

2013-09-01

The present study investigated the acute toxicity, sub-lethal toxicity and biochemical response of naphthalene in fingerlings of milkfish Chanos chanos. The 96 h acute toxicity LC50 values for C. chanos exposed to naphthalene was 5.18 μg l(-1). The estimated no observed effect concentration and lowest observed effect concentration values for naphthalene in C. chanos were 0.42 and 0.69 μg l(-1) respectively for 30 days. The estimated maximum allowable toxicant concentration for naphthalene was 0.53 μg l(-1). Biochemical enzyme markers such as lipid peroxidation, catalase, glutathione S transferase and reduced glutathione were measured in gills and liver tissues of C. chanos exposed to sub-lethal concentrations of naphthalene. Fluctuation in lipid peroxidation and catalase level suggests that naphthalene concentrations play a vital role in induction of oxidative stress in fish. Induction of reduced glutathione level and inhibition of glutathione S-transferase level was observed in naphthalene exposed C. chanos suggesting that there may be enhanced oxidative damage due to free radicals. Increasing concentration increases in number of nuclear abnormalities. The formation of micronuclei and binucleated micronuclei induction by naphthalene confirm its genotoxic potential. The highest levels of DNA damage (% tail length) were observed at 1.24 μg l(-1) of naphthalene. The study suggests that biochemical enzymes, nuclear abnormalities and DNA damage index can serve as a biological marker for naphthalene contamination.

Chemical composition and antifungal activity of the essential oils of Lavandula viridis L'Her.

PubMed

Zuzarte, Mónica; Gonçalves, Maria José; Cavaleiro, Carlos; Canhoto, Jorge; Vale-Silva, Luís; Silva, Maria João; Pinto, Eugénia; Salgueiro, Lígia

2011-05-01

In the present work we report for what we believe to be the first time the antifungal activity and mechanism of action of the essential oils of Lavandula viridis from Portugal. The essential oils were isolated by hydrodistillation and analysed by GC and GC/MS. The MIC and the minimal lethal concentration (MLC) of the essential oil and its major compounds were determined against several pathogenic fungi. The influence of subinhibitory concentrations of the essential oil on the dimorphic transition in Candida albicans was also studied, as well as propidium iodide and FUN-1 staining of Candida albicans cells by flow cytometry following short treatments with the essential oil. The oils were characterized by a high content of oxygen-containing monoterpenes, with 1,8-cineole being the main constituent. Monoterpene hydrocarbons were present at lower concentrations. According to the determined MIC and MLC values, the dermatophytes and Cryptococcus neoformans were the most sensitive fungi (MIC and MLC values ranging from 0.32 to 0.64 µl ml⁻¹), followed by Candida species (at 0.64-2.5 µl ml⁻¹). For most of these strains, MICs were equivalent to MLCs, indicating a fungicidal effect of the essential oil. The oil was further shown to completely inhibit filamentation in Candida albicans at concentrations well below the respective MICs (as low as MIC/16). Flow cytometry results suggested a mechanism of action ultimately leading to cytoplasmic membrane disruption and cell death. Our results show that L. viridis essential oils may be useful in the clinical treatment of fungal diseases, particularly dermatophytosis and candidosis, although clinical trials are required to evaluate the practical relevance of our in vitro research.

BCL2 and BCL(X)L selective inhibitors decrease mitochondrial ATP production in breast cancer cells and are synthetically lethal when combined with 2-deoxy-D-glucose.

PubMed

Lucantoni, Federico; Düssmann, Heiko; Llorente-Folch, Irene; Prehn, Jochen H M

2018-05-25

Cancer cells display differences regarding their engagement of glycolytic vs. mitochondrial oxidative phosphorylation (OXPHOS) pathway. Triple negative breast cancer, an aggressive form of breast cancer, is characterized by elevated glycolysis, while estrogen receptor positive breast cancer cells rely predominantly on OXPHOS. BCL2 proteins control the process of mitochondrial outer membrane permeabilization during apoptosis, but also regulate cellular bioenergetics. Because BCL2 proteins are overexpressed in breast cancer and targetable by selective antagonists, we here analysed the effect of BCL2 and BCL(X)L selective inhibitors, Venetoclax and WEHI-539, on mitochondrial bioenergetics and cell death. Employing single cell imaging using a FRET-based mitochondrial ATP sensor, we found that MCF7 breast cancer cells supplied with mitochondrial substrates reduced their mitochondrial ATP production when treated with Venetoclax or WEHI-539 at concentrations that per se did not induce cell death. Treatments with lower concentrations of both inhibitors also reduced the length of the mitochondrial network and the dynamics, as evaluated by quantitative confocal microscopy. We next tested the hypothesis that mitochondrial ATP production inhibition with BCL2 or BCL(X)L antagonists was synthetically lethal when combined with glycolysis inhibition. Treatment with 2-deoxy-D-glucose in combination with Venetoclax or WEHI-539 synergistically reduced the cellular bioenergetics of ER+ and TNBC breast cancer cells and abolished their clonogenic potential. Synthetic lethality was also observed when cultures were grown in 3D spheres. Our findings demonstrate that BCL2 antagonists exert potent effects on cancer metabolism independent of cell death-inducing effects, and demonstrate a synthetic lethality when these are applied in combination with glycolysis inhibitors.

BCL2 and BCL(X)L selective inhibitors decrease mitochondrial ATP production in breast cancer cells and are synthetically lethal when combined with 2-deoxy-D-glucose

PubMed Central

Lucantoni, Federico; Düssmann, Heiko; Llorente-Folch, Irene; Prehn, Jochen H.M.

2018-01-01

Cancer cells display differences regarding their engagement of glycolytic vs. mitochondrial oxidative phosphorylation (OXPHOS) pathway. Triple negative breast cancer, an aggressive form of breast cancer, is characterized by elevated glycolysis, while estrogen receptor positive breast cancer cells rely predominantly on OXPHOS. BCL2 proteins control the process of mitochondrial outer membrane permeabilization during apoptosis, but also regulate cellular bioenergetics. Because BCL2 proteins are overexpressed in breast cancer and targetable by selective antagonists, we here analysed the effect of BCL2 and BCL(X)L selective inhibitors, Venetoclax and WEHI-539, on mitochondrial bioenergetics and cell death. Employing single cell imaging using a FRET-based mitochondrial ATP sensor, we found that MCF7 breast cancer cells supplied with mitochondrial substrates reduced their mitochondrial ATP production when treated with Venetoclax or WEHI-539 at concentrations that per se did not induce cell death. Treatments with lower concentrations of both inhibitors also reduced the length of the mitochondrial network and the dynamics, as evaluated by quantitative confocal microscopy. We next tested the hypothesis that mitochondrial ATP production inhibition with BCL2 or BCL(X)L antagonists was synthetically lethal when combined with glycolysis inhibition. Treatment with 2-deoxy-D-glucose in combination with Venetoclax or WEHI-539 synergistically reduced the cellular bioenergetics of ER+ and TNBC breast cancer cells and abolished their clonogenic potential. Synthetic lethality was also observed when cultures were grown in 3D spheres. Our findings demonstrate that BCL2 antagonists exert potent effects on cancer metabolism independent of cell death-inducing effects, and demonstrate a synthetic lethality when these are applied in combination with glycolysis inhibitors. PMID:29899841

Toxicity of atrazine- and glyphosate-based formulations on Caenorhabditis elegans.

PubMed

García-Espiñeira, María; Tejeda-Benitez, Lesly; Olivero-Verbel, Jesus

2018-07-30

Atrazine and Glyphosate are herbicides massively used in agriculture for crop protection. Upon application, they are available to the biota in different ecosystems. The aim of this research was to evaluate the toxicity of Glyphosate and Atrazine based formulations (GBF and ABF, respectively). Caenorhabditis elegans was exposed to different concentrations of each single formulation, and to the mixture. Lethality, locomotion, growth, and fertility were measured as endpoints. Effects on gene expression were monitored utilizing green fluorescence protein transgenic strains. ABF caused lethality of 12%, 15%, and 18% for 6, 60, and 600 μM, respectively, displaying a dose dependence trend. GBF produced lethality of 20%, 50%, and 100% at 0.01, 10, and 100 μM, respectively. Locomotion inhibition ranged from 21% to 89% at the lowest and maximum tested concentrations for Atrazine; whereas for Glyphosate, exposure to 10 μM inhibited 87%. Brood size was decreased by 67% and 93% after treatment to 0.06 and 6 μM Atrazine, respectively; and by 23% and 93% after exposure to 0.01 and 10 μM Glyphosate, respectively. There were no significant differences in growth. Changes in gene expression occurred in all genes, highlighting the expression of sod-1, sod-4, and gpx-4 that increased more than two-fold after exposure to 600 μM ABF and 10 μM GBF. The effects observed for the mixture of these formulations were additive for lethality, locomotion and fertility. In short, GBF, ABF, and their mixture induced several toxic responses related to oxidative stress on C. elegans. Copyright © 2018 Elsevier Inc. All rights reserved.

Cardiovascular effects of equinatoxin III from the sea anemone Actinia equina (L.).

PubMed

Suput, D; Frangez, R; Bunc, M

2001-09-01

Equinatoxin III is the most hemolytic, and the least lethal of the three basic proteins isolated from the sea anemone Actinia equina (L.). Its LD50 in mice is 83 microg/kg. Preliminary results on Wistar rats have suggested cardiorespiratory arrest as a putative cause of death, but the mechanism of its action has not yet been studied. So far only equinatoxin II has been investigated more thoroughly. As equinatoxin II is less lythic, but more toxic, than equinatoxin III (its LD50 in mice=35 microg/kg), it may be assumed that haemolysis with a consequent rise in plasma potassium level is not the major factor in the lethality of equinatoxins. To assess the relative contribution of hyperkalemia in the lethality of the toxin in rat, the effects of equinatoxin III were compared to the effects of hyperkalemia caused by the injection of KCl giving the same final concentration of K+ in the plasma as that observed after an i.v. injection of 3LD50 of equinatoxin III. As coronary vasoconstriction may be an important mechanism of the cardiotoxic action of equinatoxins, the effect of EqT III on isolated porcine coronary arteries was studied by measurements of smooth muscle tension in the presence of 1-100 nM equinatoxin III. The results revealed that animals survive the elevated K+ plasma concentration caused by an i.v. application of KCl. This suggests that equinatoxin III induced haemolysis is not the major mechanism of equinatoxin III lethality. However, equinatoxin III increases the potassium induced contractions of coronary smooth muscle for 289+/-29%, suggesting that coronary vasoconstriction may be an important factor in the cardiotoxic effects of equinatoxin III.

Acute lethal toxicity, hyperkalemia associated with renal injury and hepatic damage after intravenous administration of cadmium nitrate in rats.

PubMed

Dote, Emi; Dote, Tomotaro; Shimizu, Hiroyasu; Shimbo, Yukari; Fujihara, Michiko; Kono, Koichi

2007-01-01

Cadmium nitrate Cd(NO(3))(2) (CdN) is commonly used in Ni-Cd battery factories. The possibility of accidental exposure to CdN is great. CdN is very soluble in water compared to other Cd compounds. Therefore, acute toxicity would be expected to be quick due to rapid absorption after exposure. However, the mechanisms of CdN toxicity have not been fully elucidated. We investigated the acute lethal toxicity and harmful systemic effects of acute exposure to large doses of CdN. The lethal dose and dose-response study of the liver and kidney were determined after intravenous administration of CdN in rats. The LD(50) of CdN was determined to be 5.5 mg/kg. Doses of 2.1, 4.2, 6.3 mg/kg were selected for the dose-response study. Liver injury was induced at doses greater than 4.2 mg/kg. Severe hepatic injury occurred in the 6.3 mg/kg group, which would have been caused by acute exposure to the high concentration of Cd that exceeded the critical concentration in hepatic tissue. A remarkable decrease in urine volume in the 6.3 mg/kg group indicated acute renal failure. A decrease in creatinine clearance suggested acute glomerular dysfunction at doses greater than 4.2 mg/kg. Increases in urinary N-acetyl-beta-D-glucosaminidase/creatinine, beta(2)-microglobulin and glucose in the 6.3 mg/kg group indicated proximal tubular injury. Secretion of K ion was also severely affected by proximal tubular injury and severe decreases in urine volume, and an increase in serum K ion was identified at doses greater than 4.2 mg/kg. Thus severe hyperkalemia might be associated with the cardiac-derived lethal toxicity of CdN.

Effect on the growth and development and induction of abnormalities by a glyphosate commercial formulation and its active ingredient during two developmental stages of the South-American Creole frog, Leptodactylus latrans.

PubMed

Bach, Nadia Carla; Natale, Guillermo Sebastián; Somoza, Gustavo Manuel; Ronco, Alicia Estela

2016-12-01

We evaluated the acute lethal and sublethal effects of technical-grade glyphosate (GLY) and the GLY-based commercial formulation Roundup ULTRA MAX® (RU) on two Gosner stages (Gss) 25 and 36 of the South-American Creole frog, Leptodactylus latrans. Bioassays were performed following standardized methods within a wide range of concentrations (0.0007-9.62 mg of acid equivalents per liter-a.e./L-of RU and 3-300 mg/L of GLY). The endpoints evaluated were mortality, swimming activity, growth, development, and the presence of morphologic abnormalities, especially in the mouthparts. No lethal effects were observed on larvae exposed to GLY during either Gs-25 or Gs-36. The concentrations inducing 50 % lethality in RU-exposed larvae at different exposure times and Gss ranged from 3.26 to 9.61 mg a.e./L. Swimming activity was affected by only RU. Effects on growth and development and the induction of morphologic abnormalities-like oral abnormalities and edema-were observed after exposure to either GLY or RU. Gs-25 was the most sensitive stage to both forms of the herbicide. The commercial formulation was much more toxic than the active ingredient on all the endpoints assessed. Effects on growth, development, and the induction of morphologic abnormalities observed in the range of environmental concentrations reported for agroecosystems of Argentina constitute an alert to the potential detrimental effects of the herbicide that could be affecting the fitness and survival of anurans in agroecosystems.

Developmental toxicity of bisphenol A diglycidyl ether (epoxide resin badge) during the early life cycle of a native amphibian species.

PubMed

Hutler Wolkowicz, Ianina; Svartz, Gabriela V; Aronzon, Carolina M; Pérez Coll, Christina

2016-12-01

Bisphenol A diglycidyl ether (BADGE) is used in packaging materials, in epoxy adhesives, and as an additive for plastics, but it is also a potential industrial wastewater contaminant. The aim of the present study was to evaluate the adverse effects of BADGE on Rhinella arenarum by means of standardized bioassays at embryo-larval development. The results showed that BADGE was more toxic to embryos than to larvae at all exposure times. At acute exposure, lethality rates of embryos exposed to concentrations of 0.0005 mg/L BADGE and greater were significantly higher than rates in the vehicle control, whereas lethality rates of larvae were significantly higher in concentrations of 10 mg/L BADGE and greater. The toxicity then increased significantly, with 96-h median lethal concentrations (LC50s) of 0.13 mg/L and 6.9 mg/L BADGE for embryos and larvae, respectively. By the end of the chronic period, the 336-h LC50s were 0.04 mg/L and 2.2 mg/L BADGE for embryos and larvae, respectively. This differential sensitivity was also ascertained by the 24-h pulse exposure experiments, in which embryos showed a stage-dependent toxicity, with blastula being the most sensitive stage and S.23 the most resistant. The most important sublethal effects in embryos were cell dissociation and delayed development, whereas the main abnormalities observed in larvae related to neurotoxicity, as scare response to stimuli and narcotic effect. Environ Toxicol Chem 2016;35:3031-3038. © 2016 SETAC. © 2016 SETAC.

Combined effects of Corexit EC 9500A with secondary abiotic and biotic factors in the rotifer Brachionus plicatilis.

PubMed

Williams, Michael B; Powell, Mickie L; Watts, Stephen A

2016-10-01

We examined lethality and behavioral effects of Corexit EC 9500A (C-9500A) exposure on the model marine zooplankton Brachionus plicatilis singularly and in combination with abiotic and biotic factors. C-9500A exposure at standard husbandry conditions (17.5ppt, 24°C, 200 rotifer*mL(-1) density) identified the 24h median lethal concentration, by Probit analysis, to be 107ppm for cultured B. plicatilis. Rotifers surviving exposure to higher concentrations (100 and 150ppm) exhibited a decreased swimming velocity and a reduced net to gross movement ratio. Significant interaction between C-9500A exposure and temperature or salinity was observed. Upper thermal range was reduced and maximal salinity stress was seen as ca. 25ppt. Increased or decreased nutritional availability over the exposure period did not significantly alter mortality of B. plicatilis populations at the concentrations tested. Results from this study may be useful for predicting possible outcomes on marine zooplankton following dispersant application under diverse natural conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Adverse effects of the SSRI antidepressant sertraline on early life stages of marine invertebrates.

PubMed

Estévez-Calvar, Noelia; Canesi, Laura; Montagna, Michele; Faimali, Marco; Piazza, Veronica; Garaventa, Francesca

2017-07-01

Widespread contamination of coastal environments by emerging compounds includes low concentrations of pharmaceuticals. These pollutants are not currently incorporated in monitoring programs despite their effects on non-target organisms are very little documented. Among the selective serotonin reuptake inhibitor (SSRI) antidepressants, sertraline (SRT) is one of the most prescribed globally. In this work, earlier life stages of Amphibalanus amphitrite, Brachionus plicatilis and Mytilus galloprovincialis were exposed to environmental concentrations of SRT in order to study both sub-lethal and lethal responses in 24/48 h-tests. Low concentrations of SRT altered significantly swimming behavior in A. amphitrite and B. plicatilis giving 48 h-EC 50 (μg/L) of 113.88 and 282.23, respectively whereas higher values were observed for mortality and immobilization. EC 50 embryotoxicity with M. galloprovincialis was 206.80 μg/L. This work add new data about SRT ecotoxicity on marine invertebrates and confirms the applicability of behavioral endpoints to evaluate the environmental impact of antidepressants in marine organisms. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acaricidal activity of four fractions and octadecanoic acid-tetrahydrofuran-3,4-diyl ester isolated from chloroform extracts of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae in vitro.

PubMed

Du, Yong-Hua; Li, Jin-Liang; Jia, Ren-Yong; Yin, Zhong-Qiong; Li, Xu-Ting; Lv, Cheng; Ye, Gang; Zhang, Li; Zhang, Yu-Qun

2009-07-07

Four fractions obtained from chloroform extracts of neem (Azadirachta indica) oil by column chromatography were investigated for acaricidal activity against Sarcoptes scabiei var. cuniculi larvae in vitro. Octadecanoic acid-tetrahydrofuran-3,4-diyl ester was isolated from an active fraction of the chloroform extract and its toxicity against S. scabiei larvae was tested in vitro. A complementary log-log model was used to analyse the toxicity data. Activity was found in the third fraction, with 100% corrected mortality after 4.5 h of exposure at a concentration of 200 mg ml(-1). This fraction was repeatedly re-crystallised in acetone to yield a white amorphous powder, identified as octadecanoic acid-tetrahydrofuran-3,4-diyl ester, with a median lethal concentration (LC(50)) of 0.1 mg ml(-1) at 24 h post-treatment. The median lethal time (LT(50)) for this compound was 15.3 h at a concentration of 7.5 mg ml(-1).

Enhancing the Antibiotic Antibacterial Effect by Sub Lethal Tellurite Concentrations: Tellurite and Cefotaxime Act Synergistically in Escherichia coli

PubMed Central

Molina-Quiroz, Roberto C.; Muñoz-Villagrán, Claudia M.; de la Torre, Erick; Tantaleán, Juan C.; Vásquez, Claudio C.; Pérez-Donoso, José M.

2012-01-01

The emergence of antibiotic-resistant pathogenic bacteria during the last decades has become a public health concern worldwide. Aiming to explore new alternatives to treat antibiotic-resistant bacteria and given that the tellurium oxyanion tellurite is highly toxic for most microorganisms, we evaluated the ability of sub lethal tellurite concentrations to strengthen the effect of several antibiotics. Tellurite, at nM or µM concentrations, increased importantly the toxicity of defined antibacterials. This was observed with both Gram negative and Gram positive bacteria, irrespective of the antibiotic or tellurite tolerance of the particular microorganism. The tellurite-mediated antibiotic-potentiating effect occurs in laboratory and clinical, uropathogenic Escherichia coli, especially with antibiotics disturbing the cell wall (ampicillin, cefotaxime) or protein synthesis (tetracycline, chloramphenicol, gentamicin). In particular, the effect of tellurite on the activity of the clinically-relevant, third-generation cephalosporin (cefotaxime), was evaluated. Cell viability assays showed that tellurite and cefotaxime act synergistically against E. coli. In conclusion, using tellurite like an adjuvant could be of great help to cope with several multi-resistant pathogens. PMID:22536386

Toxicity of TFM lampricide to early life stages of walleye

USGS Publications Warehouse

Seelye, J.G.; Marking, L.L.; King, E.L.; Hanson, L.H.; Bills, T.D.

1987-01-01

The authors studied the effects of the lampricide 3-trifluoromethyl-4-nitrophenol (TFM) on gametes, newly fertilized eggs, eyed eggs, larvae, and swim-up fry of the walleye Stizostedion vitreum . When gametes from sexually mature walleyes were stripped into solutions of TFM, no effects were observed during the fertilization process at concentrations up to 3.0 mg/L - three times the concentration lethal to 99.9% of larval sea lampreys Petromyzon marinus held 12 h (LC99.9) under the same test conditions. Newly fertilized eggs likewise were unaffected during water hardening by concentrations of TFM that were lethal to sea lamprey ammocoetes. Eyed eggs, sac fry, and swim-up fry yielded LC25 values that were 2.5 to 5 times greater than the 12-h LC99.9 for sea lamprey ammocoetes. The data thus indicated that all of the early life stages of walleyes tested were considerably more resistant than sea lamprey ammocoetes to TFM, and that it is unlikely they would be adversely affected by standard stream treatments to kill sea lamprey ammocoetes.

Time-response characteristic and potential biomarker identification of heavy metal induced toxicity in zebrafish.

PubMed

Yin, Jian; Wang, Ai-Ping; Li, Wan-Fang; Shi, Rui; Jin, Hong-Tao; Wei, Jin-Feng

2018-01-01

The present work aims to explore the time-response (from 24 h to 96 h) characteristic and identify early potential sensitive biomarkers of copper (Cu) (as copper chloride dihydrate), cadmium (Cd) (as cadmium acetate), lead (Pb) (as lead nitrate) and chromium (Cr) (as potassium dichromate) exposure in adult zebrafish, focusing on reactive oxygen species (ROS), SOD activity, lipid peroxidation and gene expression related to oxidative stress and inflammatory response. Furthermore, the survival rate decreased apparently by a concentration-dependent manner after Cu, Cr, Cd and Pb exposure, and we selected non-lethal concentrations 0.05 mg/L for Cu, 15 mg/L for Cr, 3 mg/L for Cd and 93.75μg/L for Pb to test the effect on the following biological indicators. Under non-lethal concentration, the four heavy metals have no apparent histological change in adult zebrafish gills. Similar trends in ROS production, MDA level and SOD activity were up-regulated by the four heavy metals, while MDA level responded more sensitive to Pb by time-dependent manner than the other three heavy metals. In addition, mRNA levels related to antioxidant system (SOD1, SOD2 and Nrf2) were up-regulated by non-lethal concentration Cu, Cr, Cd and Pb exposure. MDA level and SOD1 gene have a more delayed response to heavy metals. Genes related to immunotoxicity were increased significantly after heavy metals exposure at non-lethal concentrations. TNF-α and IL-1β gene have similar sensibility to the four heavy metals, while IL-8 gene was more responsive to Cr, Cd and Pb exposure at 48 h groups and IFN-γ gene showed more sensitivity to Cu at 48 h groups than the other heavy metals. In conclusion, the present works have suggested that the IFN-γ gene may applied as early sensitive biomarker to identify Cu-induced toxicity, while MDA content and IL-8 gene may use as early sensitive biomarkers for evaluating the risk of Pb exposure. Moreover, IL-8 and IFN-γ gene were more responsive to heavy metals, which may become early sensitive and potential biomarkers for evaluating inflammatory response induced by heavy metals. This work reinforces the concept of the usefulness of gene expression assays in the evaluation of chemicals effects and helps to establish a background data as well as contributes to evaluate early environmental risk for chemicals, even predicting toxicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid).

PubMed

Fairchild, James F; Allert, Ann; Sappington, Linda S; Nelson, Karen J; Valle, Janet

2008-03-01

We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration:time data matrix.

Using accelerated life testing procedures to compare the relative sensitivity of rainbow trout and the federally listed threatened bull trout to three commonly used rangeland herbicides (picloram, 2,4-D, and clopyralid)

USGS Publications Warehouse

Fairchild, J.F.; Allert, A.; Sappington, L.S.; Nelson, K.J.; Valle, J.

2008-01-01

We conducted 96-h static acute toxicity studies to evaluate the relative sensitivity of juveniles of the threatened bull trout (Salvelinus confluentus) and the standard cold-water surrogate rainbow trout (Onchorhyncus mykiss) to three rangeland herbicides commonly used for controlling invasive weeds in the northwestern United States. Relative species sensitivity was compared using three procedures: standard acute toxicity testing, fractional estimates of lethal concentrations, and accelerated life testing chronic estimation procedures. The acutely lethal concentrations (ALC) resulting in 50% mortality at 96 h (96-h ALC50s) were determined using linear regression and indicated that the three herbicides were toxic in the order of picloram acid > 2,4-D acid > clopyralid acid. The 96-h ALC50 values for rainbow trout were as follows: picloram, 41 mg/L; 2.4-D, 707 mg/L; and clopyralid, 700 mg/L. The 96-h ALC50 values for bull trout were as follows: picloram, 24 mg/L; 2.4-D, 398 mg/L; and clopyralid, 802 mg/L. Fractional estimates of safe concentrations, based on 5% of the 96-h ALC50, were conservative (overestimated toxicity) of regression-derived 96-h ALC5 values by an order of magnitude. Accelerated life testing procedures were used to estimate chronic lethal concentrations (CLC) resulting in 1% mortality at 30 d (30-d CLC1) for the three herbicides: picloram (1 mg/L rainbow trout, 5 mg/L bull trout), 2,4-D (56 mg/L rainbow trout, 84 mg/L bull trout), and clopyralid (477 mg/L rainbow trout; 552 mg/L bull trout). Collectively, the results indicated that the standard surrogate rainbow trout is similar in sensitivity to bull trout. Accelerated life testing procedures provided cost-effective, statistically defensible methods for estimating safe chronic concentrations (30-d CLC1s) of herbicides from acute toxicity data because they use statistical models based on the entire mortality:concentration: time data matrix. ?? 2008 SETAC.

Predicted no-effect concentration (PNEC) and assessment of risk for the fungicide, triadimefon based on reproductive fitness of aquatic organisms.

PubMed

Liu, Na; Jin, Xiaowei; Zhou, Junying; Wang, Yeyao; Yang, Qi; Wu, Fengchang; Giesy, John P; Johnson, Andrew C

2018-05-21

Triadimefon, a broad-spectrum, systemic fungicide used to protect agricultural crops is popular in China. However, sub-lethal effects of triadimefon on aquatic organisms remained poorly understood, and its risks to aquatic organisms were unclear. In the current study, thresholds for chronic toxicity to five aquatic organisms were determined and a PNEC based on reproductive fitness of nine aquatic organisms was derived through use of a species sensitivity distribution (SSD). NOECs, based on reproduction or inhabitation of growth, for Oryzias latipes, Daphnia magna, Brachionus calyciflorus, Heterocypris incongruens and Soirodela polyrhiza were 5, 25, 80, 320 and 500 μg L -1 , respectively, and the final PNEC derived was 3.66 μg L -1 . A screening-level hazard assessment of surface water based on both measured environment concentrations (ND∼5.22 μg L -1 ) in 3 lakes, 2 reservoirs and 1 river and predicted environment concentrations (0.36-65 μg L -1 ) in a simulated river and pond, identified unacceptable hazard to aquatic organisms posed by triadimefon, with maximum hazard quotients (HQs) of 1.43 and 17.8, respectively. Potential deleterious effects and hazards or risks of exposure of aquatic organisms from current patterns of use of triadimefon in surface water if of concern. Since HQs were relatively small and the benefits large, it is suggested that mitigations be applied to allow use while minimizing potential for adverse effects on aquatic organisms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Residues of organochlorine pesticides and polychlorinated biphenyls and autopsy data for bald eagles, 1973-74

USGS Publications Warehouse

Prouty, R.M.; Reichel, W.L.; Locke, L.N.; Belisle, A.A.; Cromartie, E.; Kaiser, T.E.; Lamont, T.G.; Mulhern, B.M.; Swineford, D.M.

1977-01-01

Thirty-nine bald eagles found sick or dead in 13 States during 1969 and 1970 were analyzed for pesticide residues. Residues of DDE, dieldrin, polychlorinated biphenyls (PCB's), and mercury were detected in all bald eagle carcasses; DDD residues were detected in 38; DDT, heptachlor epoxide, and dichlorobenzophenone (DCBP) were detected less frequently. Six eagles contained possible lethal levels of dieldrin in the brain, and one contained a lethal concentration of DDE (385 ppm) in the brain together with 235 ppm of PCB's. Autopsy revealed that 18 bald eagles were illegally shot; other causes of death were impact injuries, electrocution, emaciation, and infectious diseases.

Minimal investment risk of a portfolio optimization problem with budget and investment concentration constraints

NASA Astrophysics Data System (ADS)

Shinzato, Takashi

2017-02-01

In the present paper, the minimal investment risk for a portfolio optimization problem with imposed budget and investment concentration constraints is considered using replica analysis. Since the minimal investment risk is influenced by the investment concentration constraint (as well as the budget constraint), it is intuitive that the minimal investment risk for the problem with an investment concentration constraint can be larger than that without the constraint (that is, with only the budget constraint). Moreover, a numerical experiment shows the effectiveness of our proposed analysis. In contrast, the standard operations research approach failed to identify accurately the minimal investment risk of the portfolio optimization problem.

In Vitro Stretch Injury Induces Time- and Severity-Dependent Alterations of STEP Phosphorylation and Proteolysis in Neurons

PubMed Central

Mesfin, Mahlet N.; von Reyn, Catherine R.; Mott, Rosalind E.; Putt, Mary E.

2012-01-01

Abstract Striatal-enriched tyrosine phosphatase (STEP) has been identified as a component of physiological and pathophysiological signaling pathways mediated by N-methyl-d-aspartate (NMDA) receptor/calcineurin/calpain activation. Activation of these pathways produces a subsequent change in STEP isoform expression or activation via dephosphorylation. In this study, we evaluated changes in STEP phosphorylation and proteolysis in dissociated cortical neurons after sublethal and lethal mechanical injury using an in vitro stretch injury device. Sublethal stretch injury produces minimal changes in STEP phosphorylation at early time points, and increased STEP phosphorylation at 24 h that is blocked by the NMDA-receptor antagonist APV, the calcineurin-inhibitor FK506, and the sodium channel blocker tetrodotoxin. Lethal stretch injury produces rapid STEP dephosphorylation via NR2B-containing NMDA receptors, but not calcineurin, and a subsequent biphasic phosphorylation pattern. STEP61 expression progressively increases after sublethal stretch with no change in calpain-mediated STEP33 formation, while lethal stretch injury results in STEP33 formation via a NR2B-containing NMDA receptor pathway within 1 h of injury. Blocking calpain activation in the initial 30 min after stretch injury increases the ratio of active STEP in cells and blocks STEP33 formation, suggesting that STEP is an early substrate of calpain after mechanical injury. There is a strong correlation between the amount of STEP33 formed and the degree of cell death observed after lethal stretch injury. In summary, these data demonstrate that previously characterized pathways of STEP regulation via the NMDA receptor are generally conserved in mechanical injury, and suggest that calpain-mediated cleavage of STEP33 should be further examined as an early marker of neuronal fate after stretch injury. PMID:22435660

An investigation of the effects from a urethral warming system on temperature distributions during cryoablation treatment of the prostate: a phantom study.

PubMed

Favazza, C P; Gorny, K R; King, D M; Rossman, P J; Felmlee, J P; Woodrum, D A; Mynderse, L A

2014-08-01

Introduction of urethral warmers to aid cryosurgery in the prostate has significantly reduced the incidence of urethral sloughing; however, the incidence rate still remains as high as 15%. Furthermore, urethral warmers have been associated with an increase of cancer recurrence rates. Here, we report results from our phantom-based investigation to determine the impact of a urethral warmer on temperature distributions around cryoneedles during cryosurgery. Cryoablation treatments were simulated in a tissue mimicking phantom containing a urethral warming catheter. Four different configurations of cryoneedles relative to urethral warming catheter were investigated. For each configuration, the freeze-thaw cycles were repeated with and without the urethral warming system activated. Temperature histories were recorded at various pre-arranged positions relative to the cryoneedles and urethral warming catheter. In all configurations, the urethral warming system was effective at maintaining sub-lethal temperatures at the simulated surface of the urethra. The warmer action, however, was additionally demonstrated to potentially negatively impact treatment lethality in the target zone by elevating minimal temperatures to sub-lethal levels. In all needle configurations, rates of freezing and thawing were not significantly affected by the use of the urethral warmer. The results indicate that the urethral warming system can protect urethral tissue during cryoablation therapy with cryoneedles placed as close as 5mm to the surface of the urethra. Using a urethral warming system and placing multiple cryoneedles within 1cm of each other delivers lethal cooling at least 5mm from the urethral surface while sparing urethral tissue. Copyright © 2014 Elsevier Inc. All rights reserved.

Lethal and sublethal effects of aniline and chlorinated anilines on zebrafish embryos and larvae.

PubMed

Horie, Yoshifumi; Yamagishi, Takahiro; Koshio, Masaaki; Iguchi, Taisen; Tatarazako, Norihisa

2017-07-01

Environmental risk assessments show increased attention to the sublethal effects of chemicals on aquatic organisms. The Organization for Economic Cooperation and Development (OECD) established the "Fish, Short-term Toxicity Test on Embryo and Sac-fry Stages" (OECD test 212) to predict lethal effects. It is still unclear, however, whether this test can predict sublethal effects. Although their sublethal effects are still unknown, chlorinated anilines are widely used in various fields. The purpose of this study, therefore, is to investigate sublethal effects of chlorinated anilines using OECD test 212 with zebrafish, and to examine the correlation of several sublethal effects between embryo and larval stages. Embryos were exposed to aniline and nine chlorinated anilines until 8 days post-fertilization. A delayed lethal effect was observed from three of the 10 anilines tested. In the control group, the swim bladder inflated after hatching, but there was no swim-bladder inflation after exposure to the chlorinated anilines. Fertilized eggs exposed to lower concentrations of test chemicals showed effects during embryogenesis that did not affect mortality rates, such as changes in body curvature and edema. Our results show that chlorinated anilines induce not only lethal effects but also a variety of sublethal effects. Moreover, a detailed estimate of these effects requires study during both embryonic and larval stages. OECD test 212 may therefore prove useful as a method for screening chemicals for lethal and sublethal effects. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Killing Range

PubMed Central

Asal, Victor; Rethemeyer, R. Karl; Horgan, John

2015-01-01

This paper presents an analysis of the Provisional Irish Republican Army's (PIRA) brigade level behavior during the Northern Ireland Conflict (1970-1998) and identifies the organizational factors that impact a brigade's lethality as measured via terrorist attacks. Key independent variables include levels of technical expertise, cadre age, counter-terrorism policies experienced, brigade size, and IED components and delivery methods. We find that technical expertise within a brigade allows for careful IED usage, which significantly minimizes civilian casualties (a specific strategic goal of PIRA) while increasing the ability to kill more high value targets with IEDs. Lethal counter-terrorism events also significantly affect a brigade's likelihood of killing both civilians and high-value targets but in different ways. Killing PIRA members significantly decreases IED fatalities but also significantly decreases the possibility of zero civilian IED-related deaths in a given year. Killing innocent Catholics in a Brigade's county significantly increases total and civilian IED fatalities. Together the results suggest the necessity to analyze dynamic situational variables that impact terrorist group behavior at the sub-unit level. PMID:25838603

Acute and chronic bioassays with New Zealand freshwater copepods using pentachlorophenol

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

Willis, K.J.

The suitability for laboratory culture and comparative sensitivity of three species of New Zealand freshwater copepod (Calamoecia lucasi Brady, Boeckella delicata Percival, and Mesocyclops cf. leuckarti Claus) to pentachlorophenol (PCP) was assessed. Acute bioassays used two life stages (nauplii and adults). Acute 48-h lethality tests were conducted at 22 C with laboratory-cultured animals of all species and at varying temperatures with seasonally collected C. lucasi adults. Mean 48-h median lethal concentration values for nauplii ranged from 52 to 227 {micro}g/L PCP for C. lucasi and B. delicata, respectively, and from 106 to 173 {micro}g/L for adult C. Lucasi and M.more » Leuckarti, respectively. The survival rate in controls was {ge}95% in acute tests, with the exception of C. lucasi nauplii, in which it was 60%. Mean 48-h median lethal concentration values for seasonally collected C. lucasi adults were significantly higher in summer than in all other seasons. Chronic sublethal tests starting with nauplii <24 h old measured time to metamorphosis. Pentachlorophenol delayed metamorphosis in all species. Chronic toxicity values were 14.61, and 104 {micro}g/L PCP for C. lucasi, B. delicata, and M. leuckarti, respectively. The mortality rate in controls was also high in C. lucasi sublethal tests (65%), and of the three species, they were the most difficult to culture.« less

Sub-lethal effects of herbicides penoxsulam, imazamox, fluridone and glyphosate on Delta Smelt (Hypomesus transpacificus).

PubMed

Jin, Jiali; Kurobe, Tomofumi; Ramírez-Duarte, Wilson F; Bolotaolo, Melissa B; Lam, Chelsea H; Pandey, Pramod K; Hung, Tien-Chieh; Stillway, Marie E; Zweig, Leanna; Caudill, Jeffrey; Lin, Li; Teh, Swee J

2018-04-01

Concerns regarding non-target toxicity of new herbicides used to control invasive aquatic weeds in the San Francisco Estuary led us to compare sub-lethal toxicity of four herbicides (penoxsulam, imazamox, fluridone, and glyphosate) on an endangered fish species Delta Smelt (Hypomesus transpacificus). We measured 17β-estradiol (E2) and glutathione (GSH) concentrations in liver, and acetylcholinesterase (AChE) activity in brain of female and male fish after 6 h of exposure to each of the four herbicides. Our results indicate that fluridone and glyphosate disrupted the E2 concentration and decreased glutathione concentration in liver, whereas penoxsulam, imazamox, and fluridone inhibited brain AChE activity. E2 concentrations were significantly increased in female and male fish exposed to 0.21 μM of fluridone and in male fish exposed to 0.46, 4.2, and 5300 μM of glyphosate. GSH concentrations decreased in males exposed to fluridone at 2.8 μM and higher, and glyphosate at 4.2 μM. AChE activity was significantly inhibited in both sexes exposed to penoxsulam, imazamox, and fluridone, and more pronounced inhibition was observed in females. The present study demonstrates the potential detrimental effects of these commonly used herbicides on Delta Smelt. Copyright © 2018 Elsevier B.V. All rights reserved.

Albendazole in environment: faecal concentrations in lambs and impact on lower development stages of helminths and seed germination.

PubMed

Prchal, Lukáš; Podlipná, Radka; Lamka, Jiří; Dědková, Tereza; Skálová, Lenka; Vokřál, Ivan; Lecová, Lenka; Vaněk, Tomáš; Szotáková, Barbora

2016-07-01

Albendazole (ABZ), widely used benzimidazole anthelmintic, administered to animals enters via excrements into environment and may impact non-target organisms. Moreover, exposure of lower development stages of helminths to anthelmintics may also encourage the development of drug-resistant strains of helminths. In present project, the kinetics of ABZ (10 mg kg(-1) p.o.) and its metabolite (ABZ.SO, ABZSO2) elimination in faeces from treated Texel lambs were studied using UHPLC/MS/MS with the aim to find out their concentrations achievable in the environment. Consequently, the effect of these compounds on lower development stages of Barber's pole worm (Haemonchus contortus) and on germination of white mustard (Sinapis alba) seeds was evaluated. The results showed that ABZ concentrations in faeces excreted in 4-60 h after treatment were above the concentrations lethal for H. contortus eggs. Moreover, pre-incubation with sub-lethal doses of ABZ and ABZ.SO did not increase the resistance of H. contortus eggs and larvae to anthelmintics. On the other hand, concentrations of ABZ and ABZ.SO in faeces are so high that might have negative influence on non-target soil invertebrates. As neither ABZ nor its metabolites affect the germination of mustard seeds, phytoremediation could be considered as potential tool for detoxification of ABZ in the environment.

Trophic cascades in rocky shore tide pools: distinguishing lethal and nonlethal effects.

PubMed

Trussell, Geoffrey C; Ewanchuk, Patrick J; Bertness, Mark D; Silliman, Brian R

2004-05-01

The effects of predators on the density of their prey can have positive indirect effects on the abundance of the prey's resource via a trophic cascade. This concept has strongly influenced contemporary views of how communities are structured. However, predators also can transmit indirect effects by inducing changes in prey traits. We show that the mere presence of predator risk cues can initiate a trophic cascade in rocky shore tide pools. In large (mean surface area =9 m2), natural tide pools, we manipulated crab density and their foraging ability to examine the relative importance of lethal (density-mediated) and non-lethal (trait-mediated) predator effects to algal community development. We found that perceived predation risk reduced snail density as much as the direct predation treatment, showing that green crab predation was not an important factor regulating local snail density. Instead, snail emigration away from resident crabs appears to be the most important factor regulating local snail density. As a result, the abundance of ephemeral green algae was similar in the predation risk and direct predation treatments, suggesting that the consumption of snails by crabs plays a minimal role in mediating the trophic cascade. Increased attention to trait-mediated effects that are transmitted by predator-induced changes in prey behavior may change our view of how predators exert their strong influence on community structure.

A Mouse Model of Acinetobacter baumannii-Associated Pneumonia Using a Clinically Isolated Hypervirulent Strain

PubMed Central

Harris, Greg; Kuo Lee, Rhonda; Lam, Christopher K.; Kanzaki, Gregory; Patel, Girishchandra B.; Xu, H. Howard

2013-01-01

Acinetobacter baumannii is an important emerging pathogen in health care-acquired infections and is responsible for severe nosocomial and community-acquired pneumonia. Currently available mouse models of A. baumannii pneumonia show poor colonization with little to no extrapulmonary dissemination. Here, we describe a mouse model of A. baumannii pneumonia using a clinical isolate (LAC-4 strain) that reliably reproduces the most relevant features of human pulmonary A. baumannii infection and pathology. Using this model, we have shown that LAC-4 infection induced rapid bacterial replication in the lungs, significant extrapulmonary dissemination, and severe bacteremia by 24 h postintranasal inoculation. Infected mice showed severe bronchopneumonia and dilatation and inflammatory cell infiltration in the perivascular space. More significantly, 100% of C57BL/6 and BALB/c mice succumbed to 108 CFU of LAC-4 inoculation within 48 h. When this model was used to assess the efficacy of antimicrobials, all mice treated with imipenem and tigecycline survived a lethal intranasal challenge, with minimal clinical signs and body weight loss. Moreover, intranasal immunization of mice with formalin-fixed LAC-4 protected 40% of mice from a lethal (100× 100% lethal dose) intraperitoneal challenge. Thus, this model offers a reproducible acute course of A. baumannii pneumonia without requiring additional manipulation of host immune status, which will facilitate the development of therapeutic agents and vaccines against A. baumannii pneumonia in humans. PMID:23689726

Behavior of Listeria monocytogenes on frankfurters surface treated with lauric arginate and/or a liquid smoke extract delivered using the Sprayed Lethality in Container (SLIC®) technology

USDA-ARS?s Scientific Manuscript database

The objective of this study was to determine the viability of Listeria monocytogenes (LM) on commercially-produced frankfurters prepared without lactates that were surface treated with 0 or 4 mL of a blend of LAE (CytoGuard; 1.0% LAE final concentration) diluted in a concentrated liquid smoke extrac...

Toxic effects of the neem oil (Azadirachta indica) formulation on the stink bug predator, Podisus nigrispinus (Heteroptera: Pentatomidae).

PubMed

Zanuncio, José Cola; Mourão, Sheila Abreu; Martínez, Luis Carlos; Wilcken, Carlos Frederico; Ramalho, Francisco S; Plata-Rueda, Angelica; Soares, Marcus Alvarenga; Serrão, José Eduardo

2016-09-06

This research investigated the effects of neem oil on mortality, survival and malformations of the non-target stink bug predator, Podisus nigrispinus. Neurotoxic and growth inhibitor insecticides were used to compare the lethal and sublethal effects from neem oil on this predator. Six concentrations of neem oil were topically applied onto nymphs and adults of this predator. The mortality rates of third, fourth, and fifth instar nymphs increased with increasing neem oil concentrations, suggesting low toxicity to P. nigrispinus nymphs. Mortality of adults was low, but with sublethal effects of neem products on this predator. The developmental rate of P. nigrispinus decreased with increasing neem oil concentrations. Longevity of fourth instar nymphs varied from 3.74 to 3.05 d, fifth instar from 5.94 to 4.07 d and adult from 16.5 and 15.7 d with 0.5 and 50% neem doses. Podisus nigrispinus presented malformations and increase with neem oil concentrations. The main malformations occur in wings, scutellum and legs of this predator. The neem oil at high and sub lethal doses cause mortality, inhibits growth and survival and results in anomalies on wings and legs of the non-traget predator P. nigrispinus indicating that its use associated with biological control should be carefully evaluated.

Toxicity assessment of sodium fluoride in Drosophila melanogaster after chronic sub-lethal exposure.

PubMed

Dutta, Moumita; Rajak, Prem; Khatun, Salma; Roy, Sumedha

2017-01-01

Sodium fluoride (NaF), one of the most frequently used fluoride compound is composed of Na + and F - . Apart from its use in water fluoridation, NaF also acts as a major component for different dental products like toothpastes, gels and mouth rinses etc. The present study was carried out to explore the toxic impact of chronic NaF exposure on a non-target organism, Drosophila melanogaster. The larvae exposed to different concentrations of NaF through food showed a significant increase in HSP70 expression both qualitatively and quantitatively. The altered tail length and tail intensity in Comet assay validate the increased DNA damage in treated larvae. The activity of AChE, oxidative stress marker enzymes, phase I and phase II detoxifying enzymes were found to be significantly inhibited in the treated larvae when compared to control though there was no evidence of dose dependent change in each case. The alterations in the mentioned parameters can be due to increased body Fluoride ion (F - ) concentration since the analysis with ion electrode analyzer revealed that F - concentration increased significantly with NaF treatment. Hence, the results suggest that D. melanogaster manifest prominent toxic response when subjected to chronic exposure to sub-lethal NaF concentrations. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tuning Gene Activity by Inducible and Targeted Regulation of Gene Expression in Minimal Bacterial Cells.

PubMed

Mariscal, Ana M; Kakizawa, Shigeyuki; Hsu, Jonathan Y; Tanaka, Kazuki; González-González, Luis; Broto, Alicia; Querol, Enrique; Lluch-Senar, Maria; Piñero-Lambea, Carlos; Sun, Lijie; Weyman, Philip D; Wise, Kim S; Merryman, Chuck; Tse, Gavin; Moore, Adam J; Hutchison, Clyde A; Smith, Hamilton O; Tomita, Masaru; Venter, J Craig; Glass, John I; Piñol, Jaume; Suzuki, Yo

2018-05-22

Functional genomics studies in minimal mycoplasma cells enable unobstructed access to some of the most fundamental processes in biology. Conventional transposon bombardment and gene knockout approaches often fail to reveal functions of genes that are essential for viability, where lethality precludes phenotypic characterization. Conditional inactivation of genes is effective for characterizing functions central to cell growth and division, but tools are limited for this purpose in mycoplasmas. Here we demonstrate systems for inducible repression of gene expression based on clustered regularly interspaced short palindromic repeats-mediated interference (CRISPRi) in Mycoplasma pneumoniae and synthetic Mycoplasma mycoides, two organisms with reduced genomes actively used in systems biology studies. In the synthetic cell, we also demonstrate inducible gene expression for the first time. Time-course data suggest rapid kinetics and reversible engagement of CRISPRi. Targeting of six selected endogenous genes with this system results in lowered transcript levels or reduced growth rates that agree with lack or shortage of data in previous transposon bombardment studies, and now produces actual cells to analyze. The ksgA gene encodes a methylase that modifies 16S rRNA, rendering it vulnerable to inhibition by the antibiotic kasugamycin. Targeting the ksgA gene with CRISPRi removes the lethal effect of kasugamycin and enables cell growth, thereby establishing specific and effective gene modulation with our system. The facile methods for conditional gene activation and inactivation in mycoplasmas open the door to systematic dissection of genetic programs at the core of cellular life.

Caffeine: cognitive and physical performance enhancer or psychoactive drug?

PubMed

Cappelletti, Simone; Piacentino, Daria; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

2015-01-01

Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine's mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine's interaction with other substances or to the individuals' preexisting metabolism alterations or diseases.

Caffeine: Cognitive and Physical Performance Enhancer or Psychoactive Drug?

PubMed Central

Cappelletti, Simone; Daria, Piacentino; Sani, Gabriele; Aromatario, Mariarosaria

2015-01-01

Caffeine use is increasing worldwide. The underlying motivations are mainly concentration and memory enhancement and physical performance improvement. Coffee and caffeine-containing products affect the cardiovascular system, with their positive inotropic and chronotropic effects, and the central nervous system, with their locomotor activity stimulation and anxiogenic-like effects. Thus, it is of interest to examine whether these effects could be detrimental for health. Furthermore, caffeine abuse and dependence are becoming more and more common and can lead to caffeine intoxication, which puts individuals at risk for premature and unnatural death. The present review summarizes the main findings concerning caffeine’s mechanisms of action (focusing on adenosine antagonism, intracellular calcium mobilization, and phosphodiesterases inhibition), use, abuse, dependence, intoxication, and lethal effects. It also suggests that the concepts of toxic and lethal doses are relative, since doses below the toxic and/or lethal range may play a causal role in intoxication or death. This could be due to caffeine’s interaction with other substances or to the individuals' preexisting metabolism alterations or diseases. PMID:26074744

Short-term exposure to low doses of rotenone induces developmental, biochemical, behavioral, and histological changes in fish.

PubMed

Melo, Karina Motta; Oliveira, Rhaul; Grisolia, Cesar Koppe; Domingues, Inês; Pieczarka, Julio Cesar; de Souza Filho, José; Nagamachi, Cleusa Yoshiko

2015-09-01

Rotenone, a natural compound derived from plants of the genera Derris and Lonchocarpus, is used worldwide as a pesticide and piscicide. This study aims to assess short-term toxicity of rotenone to early-life stages of the fish Danio rerio and Poecilia reticulata using a wide and integrative range of biomarkers (developmental, biochemical, behavioral, and histopathological). Moreover, the species sensitivity distribution (SSD) approach was used to compare rotenone acute toxicity to fish species. Toxicity tests were based on the OECD protocols, fish embryo toxicity test (for D. rerio embryos), and fish acute toxicity test (for P. reticulata juveniles). D. rerio embryos were used to estimate lethal concentrations and analyze embryonic and enzymatic alterations (activity of catalase, glutathione-S-transferase, and cholinesterase), while P. reticulata juveniles were used for the assessment of histological damage in the gills and liver. Rotenone induced significant mortality in zebrafish embryos with a 96-h lethal concentration 50% (LC50) = 12.2 μg/L. Rotenone was embryotoxic, affecting the development of D. rerio embryos, which showed cardiac edema; tail deformities; loss of equilibrium; and a general delay characterized by lack of tail detachment, delayed somite formation, yolk sac absorption, and lack of pigmentation. Biochemical biomarker inhibition was observed for concentrations ≥1 μg/L for CAT and glutathione-S-transferase (GST) and for cholinesterase (ChE) in concentration from 10 μg/L. Behavioral changes were observed for P. reticulata juveniles exposed to concentrations equal to or above 25 μg/L of rotenone; moreover, histological damage in the liver and gills of fish exposed to concentrations equal to or above 2.5 μg/L could be observed. A hazard concentration 5% (HC5) of 3.2 μg/L was estimated considering the acute toxicity data for different fish species (n = 49). Lethal and sublethal effects of rotenone raise a concern about its effects on nontarget fish species, especially because rotenone and its metabolite rotenolone are frequently reported in the microgram range in natural environments for several days after field applications. Rotenone should be used with caution. Given the high toxicity and wide range of sublethal effects here reported, further studies in a chronic exposure scenario are recommended.

Toxicity of inhaled methyl isocyanate in F344/N rats and B6C3F1 mice. I. Acute exposure and recovery studies.

PubMed Central

Bucher, J R; Gupta, B N; Adkins, B; Thompson, M; Jameson, C W; Thigpen, J E; Schwetz, B A

1987-01-01

Male and female F344/N rats and B6C3F1 mice were exposed to lethal and sublethal concentrations of methyl isocyanate by inhalation. Mortality, clinical signs, body and organ weights, and changes in clinical pathology and hematology were monitored immediately after 2-hr exposures and during the ensuing 3 months. Additional studies investigated the possible involvement of cyanide in the toxicity of methyl isocyanate. During exposures, signs of restlessness, lacrimation, and a reddish discharge from the nose and mouth were evident in rats and mice. Following exposures, rats and mice were dyspneic and weak. Deaths of rats and mice exposed to lethal concentrations (20 to 30 ppm) began within 15-18 hr, with males more prone to early death than females. A second wave of deaths occurred after 8 to 10 days, affecting primarily female rats and mice exposed to 20 to 30 ppm of methyl isocyanate, and male and female rats exposed to 10 ppm. Most deaths occurred during the first month following the exposures and were preceded by periods of severe respiratory distress. Body weights decreased in proportion to dose early, but then weight gain resumed in survivors at control rates. The only organ with a consistent, dose-related weight change was the lung, which was heavier throughout the studies in animals exposed to high concentrations of methyl isocyanate. No significant clinical pathology, or hematologic changes were observed in exposed rats. Blood and brain cholinesterase were not inhibited. Studies attempting to measure cyanide in the blood of methyl isocyanate-exposed rats, and attempting to affect lethality with a cyanide antidote (sodium nitrite and sodium thiosulfate) gave negative results.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3622444

Lethal and sublethal effects of azadirachtin and cypermethrin on Habrobracon hebetor (Hymenoptera: Braconidae).

PubMed

Abedi, Zahra; Saber, Moosa; Gharekhani, Gholamhossein; Mehrvar, Ali; Kamita, Shizuo George

2014-04-01

Habrobracon hebetor Say is an ectoparasitoid of larval stage of various lepidopteran pests. Lethal and sublethal effects of azadirachtin and cypermethrin were evaluated on adult and preimaginal stages of H. hebetor under laboratory conditions. Contact exposure bioassays with adults indicated that the lethal concentration (LC50) of two commercial azadirachtin-containing formulations, NeemGuard and BioNeem, were 43.5 and 10.2 microg a.i./ml, respectively. The LC50 of cypermethrin was 5.4 microg a.i./ml. When larval stage of H. hebetor was exposed to these insecticides with a field recommended concentration of NeemGuard, BioNeem, or cypermethrin by a dip protocol, the emergence rate was reduced by 39.0, 36.6, and 97.6%, respectively. To assay the sublethal effects of these insecticides, adult wasps were exposed to an LC30 concentration of the insecticides, and then demographic parameters of the surviving wasps were determined. Fecundity, fertility, and parameters including the intrinsic rate of increase (r(m)) were affected negatively. The r(m) values following exposure to NeemGuard, BioNeem, cypermethrin, or mock treatment were 0.143, 0.149, 0.160, and 0.179, respectively, female offspring per female per day, respectively. The current study showed that cypermethrin had more acute toxicity on larval and adult stages of H. hebetor compared with azadirachin. The commercial formulations of azadirachtin and cypermethrin negatively affected most of the life table parameters of the parasitoid. Semifield and field studies are needed for obtaining more applicable results on combining H. hebetor and the tested insecticides for an integrated pest management-based strategy for crop protection.

[Relationship between lethality of hemodialysis patients, erythropoietin dosage for renal anemia treatment and hemodialysis quality].

PubMed

Ziginskiene, Edita; Kuzminskis, Vytautas; Bumblyte, Inga Arūne

2003-01-01

In December of 1999 and 2000 we visited all hemodialysis centers of Lithuania and collected data about all hemodialysis patients, using special questionnaires. The aim of the study was to evaluate the relationship between lethality of hemodialysis patients, erythropoietin dosage for renal anemia treatment and hemodialysis quality. The patients with higher Kt/V, higher levels of iron and albumin, normal levels of phosphorus and parathyroid hormone (PTH) requested lower doses of erythropoietin (analysis of the patients who were on hemodialysis in 2000 more than 6 months). So, we can conclude that adequate hemodialysis procedure and good management of hemodialysis patient are leading to the decrease request of erythropoietin doses for anemia treatment. We compared two groups of patients in order to examine relationship between hemodialysis quality and lethality of hemodialysis patients. We selected incident patients registered in December of 1999 and we divided these patients in December of 2000 in two groups: a) 175 patients, who continued hemodialysis treatment and b) 41 patients, who died in 2000. The results revealed, that dead patients were elder, their duration of weekly hemodialysis was shorter, Hb concentration lower, they had worse nutritional status (blood albumin level was lower). Lethality was associated with underlying diseases such as diabetes, hypertensive nephropathy and renal amyloidosis.

Adaptive Landscapes of Resistance Genes Change as Antibiotic Concentrations Change.

PubMed

Mira, Portia M; Meza, Juan C; Nandipati, Anna; Barlow, Miriam

2015-10-01

Most studies on the evolution of antibiotic resistance are focused on selection for resistance at lethal antibiotic concentrations, which has allowed the detection of mutant strains that show strong phenotypic traits. However, solely focusing on lethal concentrations of antibiotics narrowly limits our perspective of antibiotic resistance evolution. New high-resolution competition assays have shown that resistant bacteria are selected at relatively low concentrations of antibiotics. This finding is important because sublethal concentrations of antibiotics are found widely in patients undergoing antibiotic therapies, and in nonmedical conditions such as wastewater treatment plants, and food and water used in agriculture and farming. To understand the impacts of sublethal concentrations on selection, we measured 30 adaptive landscapes for a set of TEM β-lactamases containing all combinations of the four amino acid substitutions that exist in TEM-50 for 15 β-lactam antibiotics at multiple concentrations. We found that there are many evolutionary pathways within this collection of landscapes that lead to nearly every TEM-genotype that we studied. While it is known that the pathways change depending on the type of β-lactam, this study demonstrates that the landscapes including fitness optima also change dramatically as the concentrations of antibiotics change. Based on these results we conclude that the presence of multiple concentrations of β-lactams in an environment result in many different adaptive landscapes through which pathways to nearly every genotype are available. Ultimately this may increase the diversity of genotypes in microbial populations. © The Author 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Microbiota source impact in vitro metabolite colonic production and anti-proliferative effect of spent coffee grounds on human colon cancer cells (HT-29).

PubMed

Hernández-Arriaga, Angélica María; Dave Oomah, B; Campos-Vega, Rocio

2017-07-01

Human gut flora-mediated non-digestible fraction of spent coffee grounds (hgf-NDSCG) was evaluated for its chemopreventive effect and molecular mechanisms involved on human colon adenocarcinoma HT-29 cell survival using two different microbiota source [lean (L) and overweight (OW)]. The source of human gut flora (hgf) (L or OW) affected the pH of hgf-NDSCG only minimally, but linearly reduced those of hgf-inulin. The variability between lean and overweight microbiota was characterized by the metabolism and/or bioaccessibility of different phenolic metabolites, their intermediate and end products as well as by variable time courses. Apoptosis of colon cancer HT-29 cells depended on the microbiota source with the lean microbiota expressing a low lethal concentration 50 (LC 50 /L-hgf-NDSCG=13.5%). We demonstrate that NDSCG and its colonic metabolite from lean microbiota induced HT-29 cell apoptosis by reducing catalase and 8-iso-prostaglandin F2α as biomarkers of in vivo oxidative stress as the primary mechanism underlying its overall chemoprotection against colon cancer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Live Bacterial Physiology Visualized with 5 nm Resolution Using Scanning Transmission Electron Microscopy.

PubMed

Kennedy, Eamonn; Nelson, Edward M; Tanaka, Tetsuya; Damiano, John; Timp, Gregory

2016-02-23

It is now possible to visualize at nanometer resolution the infection of a living biological cell with virus without compromising cell viability using scanning transmission electron microscopy (STEM). To provide contrast while preserving viability, Escherichia coli and P1 bacteriophages were first positively stained with a very low concentration of uranyl acetate in minimal phosphate medium and then imaged with low-dose STEM in a microfluidic liquid flow cell. Under these conditions, it was established that the median lethal dose of electrons required to kill half the tested population was LD50 = 30 e(-)/nm(2), which coincides with the disruption of a wet biological membrane, according to prior reports. Consistent with the lateral resolution and high-contrast signal-to-noise ratio (SNR) inferred from Monte Carlo simulations, images of the E. coli membrane, flagella, and the bacteriophages were acquired with 5 nm resolution, but the cumulative dose exceeded LD50. On the other hand, with a cumulative dose below LD50 (and lower SNR), it was still possible to visualize the infection of E. coli by P1, showing the insertion of viral DNA within 3 s, with 5 nm resolution.

Assessing Trophic Position and Mercury Accumulation in Sanpping Turtles

EPA Science Inventory

This study determined the trophic position and the total mercury concentrations of snapping turtles (Chelydra serpentina) captured from 26 freshwater sites in Rhode Island. Turtles were captured in baited wire cages, and a non-lethal sampling technique was used in which tips of ...

Inhalation toxicology. IV., Times to incapacitation and death for rats exposed continuously to atmospheric hydrogen chloride gas.

DOT National Transportation Integrated Search

1985-05-01

Laboratory rats were exposed continuously to measured atmospheric concentrations of hydrogen chloride (HC1) gas until they expired. The exposure time required to produce lethality was measured, as was the time at which physical incapacitation occurre...

Effects of low-molecular-weight organic acids on the acute lethality, accumulation, and enzyme activity of cadmium in Eisenia fetida in a simulated soil solution.

PubMed

Liu, Hai-Long; Wang, Yu-Jun; Xuan, Liang; Dang, Fei; Zhou, Dong-Mei

2017-04-01

In the present study, the effects of low-molecular-weight organic acids (LMWOAs) on the toxicity of cadmium (Cd) to Eisenia fetida were investigated in a simulated soil solution. The LMWOAs protected E. fetida from Cd toxicity, as indicated by the increased median lethal concentration (LC50) values and the increased activity of superoxide dismutase. In addition, Cd concentrations in E. fetida decreased dramatically in the presence of LMWOAs. These results were likely because of the complexation between Cd and LMWOAs, which decreased the bioavailability and consequential toxicity of Cd to E. fetida. Notably, LMWOAs reduced Cd toxicity in decreasing order (ethylenediamine tetraacetic acid [EDTA] > citric acid > oxalic acid > malic acid > acetic acid), which was consistent with the decreasing complexation constants between LMWOAs and Cd. These results advance our understanding of the interactions between Cd and LMWOAs in soil. Environ Toxicol Chem 2017;36:1005-1011. © 2016 SETAC. © 2016 SETAC.

Trichomonas vaginalis antimicrobial drug resistance in 6 US cities, STD Surveillance Network, 2009-2010.

PubMed

Kirkcaldy, Robert D; Augostini, Peter; Asbel, Lenore E; Bernstein, Kyle T; Kerani, Roxanne P; Mettenbrink, Christie J; Pathela, Preeti; Schwebke, Jane R; Secor, W Evan; Workowski, Kimberly A; Davis, Darlene; Braxton, Jim; Weinstock, Hillard S

2012-06-01

Nitroimidazoles (metronidazole and tinidazole) are the only recommended drugs for treating Trichomonas vaginalis infection, and previous samples that assessed resistance of such isolates have been limited in geographic scope. We assessed the prevalence of in vitro aerobic metronidazole and tinidazole resistance among T. vaginalis isolates from multiple geographic sites in the United States. Swab specimens were obtained from women who underwent routine pelvic examinations at sexually transmitted disease clinics in 6 US cities. Cultured T. vaginalis isolates were tested for nitroimidazole resistance (aerobic minimum lethal concentration [MLC] >50 µg/mL). Of 538 T. vaginalis isolates, 23 (4.3%) exhibited low-level in vitro metronidazole resistance (minimum lethal concentrations 50-100 µg/mL). No isolates exhibited moderate- to high-level metronidazole resistance or tinidazole resistance. Results highlight the possibility that reliance on a single class of antimicrobial drugs for treating T. vaginalis infections may heighten vulnerability to emergence of resistance. Thus, novel treatment options are needed.

Comparative acute toxicity of gallium(III), antimony(III), indium(III), cadmium(II), and copper(II) on freshwater swamp shrimp (Macrobrachium nipponense).

PubMed

Yang, Jen-Lee

2014-04-01

Acute toxicity testing were carried out the freshwater swamp shrimp, Macrobrachium nipponense, as the model animal for the semiconductor applied metals (gallium, antimony, indium, cadmium, and copper) to evaluate if the species is an suitable experimental animal of pollution in aquatic ecosystem. The static renewal test method of acute lethal concentrations determination was used, and water temperature was maintained at 24.0 ± 0.5°C. Data of individual metal obtained from acute toxicity tests were determined using probit analysis method. The median lethal concentration (96-h LC50) of gallium, antimony, indium, cadmium, and copper for M. nipponense were estimated as 2.7742, 1.9626, 6.8938, 0.0539, and 0.0313 mg/L, respectively. Comparing the toxicity tolerance of M. nipponense with other species which exposed to these metals, it is obviously that the M. nipponense is more sensitive than that of various other aquatic animals.

Non-Lethal Endotoxin Injection: A Rat Model of Hypercoagulability.

PubMed

Brooks, Marjory B; Turk, James R; Guerrero, Abraham; Narayanan, Padma K; Nolan, John P; Besteman, Elizabeth G; Wilson, Dennis W; Thomas, Roberta A; Fishman, Cindy E; Thompson, Karol L; Ellinger-Ziegelbauer, Heidrun; Pierson, Jennifer B; Paulman, April; Chiang, Alan Y; Schultze, Albert E

2017-01-01

Systemic inflammation co-activates coagulation, which unchecked culminates in a lethal syndrome of multi-organ microvascular thrombosis known as disseminated intravascular coagulation (DIC). We studied an endotoxin-induced inflammatory state in rats to identify biomarkers of hemostatic imbalance favoring hypercoagulability. Intraperitoneal injection of LPS at 15 mg/kg body weight resulted in peripheral leukopenia and widespread neutrophilic sequestration characteristic of an acute systemic inflammatory response. Early indicators of hemostatic pathway activation developed within 4 hours, including increased circulating concentrations of procoagulant extracellular vesicles (EVs), EVs expressing endothelial cell and platelet membrane markers, and high concentration of soluble intercellular adhesion molecule-1 (sICAM-1), plasminogen activator inhibitor-1 (PAI-1), and D-dimers. Inflammation persisted throughout the 48-hour observation period; however, increases were found in a subset of serum microRNA (miRNA) that coincided with gradual resolution of hemostatic protein abnormalities and reduction in EV counts. Dose-adjusted LPS treatment in rats provides a time-course model to develop biomarker profiles reflecting procoagulant imbalance and rebalance under inflammatory conditions.

Weakly electric fish for biomonitoring water quality.

PubMed

Clausen, Juergen; van Wijk, Roeland; Albrecht, Henning

2012-06-01

Environmental pollution is a major issue that calls for suitable monitoring systems. The number of possible pollutants of municipal and industrial water grows annually as new chemicals are developed. Technical devices for pollutant detection are constructed in a way to detect a specific and known array of pollutants. Biological systems react to lethal or non-lethal environmental changes without pre-adjustment, and a wide variety have been employed as broad-range monitors for water quality. Weakly electric fish have proven particularly useful for the purpose of biomonitoring municipal and industrial waters. The frequency of their electric organ discharges directly correlates with the quality of the surrounding water and, in this way, concentrations of toxicants down to the nanomolar range have been successfully detected by these organisms. We have reviewed the literature on biomonitoring studies to date, comparing advantages and disadvantages of this test system and summarizing the lowest concentrations of various toxicants tested. Eighteen publications were identified investigating 35 different chemical substances and using six different species of weakly electric fish.

Effects of carbon dioxide on juveniles of the freshwater mussel (Lampsilis siliquoidea [Unionidae])

USGS Publications Warehouse

Waller, Diane L.; Bartsch, Michelle; Fredricks, Kim; Bartsch, Lynn; Schleis, Sue M.; Lee, Sheldon

2017-01-01

Carbon dioxide (CO2) has shown promise as a tool to control movements of invasive Asian carp, but its effects on native freshwater biota have not been well studied. The authors evaluated lethal and sublethal responses of juvenile fatmucket (Lampsilis siliquoidea) mussels to CO2 at levels (43–269 mg/L, mean concentration) that bracket concentrations effective for deterring carp movement. The 28-d lethal concentration to 50% of the mussels was 87.0 mg/L (95% confidence interval [CI] 78.4–95.9) and at 16-d postexposure, 76.0 mg/L (95% CI 62.9–90.3). A proportional hazards regression model predicted that juveniles could not survive CO2 concentrations >160 mg/L for more than 2 wk or >100 mg/L CO2 for more than 30 d. Mean shell growth was significantly lower for mussels that survived CO2 treatments. Growth during the postexposure period did not differ among treatments, indicating recovery of the mussels. Also, CO2 caused shell pitting and erosion. Behavioral effects of CO2 included movement of mussels to the substrate surface and narcotization at the highest concentrations. Mussels in the 110 mg/L mean CO2treatment had the most movements in the first 3 d of exposure. If CO2 is infused continuously as a fish deterrent, concentrations <76 mg/L are recommended to prevent juvenile mussel mortality and shell damage. Mussels may survive and recover from brief exposure to higher concentrations.

Making sense of nickel accumulation and sub-lethal toxic effects in saline waters: Fate and effects of nickel in the green crab, Carcinus maenas.

PubMed

Blewett, Tamzin A; Glover, Chris N; Fehsenfeld, Sandra; Lawrence, Michael J; Niyogi, Som; Goss, Greg G; Wood, Chris M

2015-07-01

In freshwater, invertebrates nickel (Ni) is considered an ionoregulatory toxicant, but its mechanism of toxicity in marine settings, and how this varies with salinity, is poorly understood. This study investigated Ni accumulation and physiological mechanisms of sub-lethal Ni toxicity in the euryhaline green crab Carcinus maenas. Male crabs were exposed to 8.2μg/L (the US EPA chronic criterion concentration for salt waters) of waterborne Ni (radiolabelled with (63)Ni) at three different salinities, 20%, 60% and 100% SW for 24h. Whole body Ni accumulation in 20% SW was 3-5 fold greater than in 60% or 100% SW, and >80% of accumulated Ni was in the carapace at all salinities. Ni also accumulated in posterior gill 8, which showed a higher accumulation in 20% SW than in other salinities, a pattern also seen at higher exposure concentrations of Ni (500 and 3000μg/L). Gill perfusion experiments revealed that Ni was taken up by both anterior and posterior gills, but in 20% SW the posterior gill 8, which performs ionoregulatory functions, accumulated more Ni than the anterior gill 5, which primarily has a respiratory function. The sub-lethal consequences of Ni exposure were investigated by placing crabs in Ni concentrations of 8.2, 500, and 3000μg/L at 20, 60 or 100% SW for 24h. In 20% SW, haemolymph Ca levels were significantly decreased by exposure to Ni concentrations of 8.2μg/L or higher, whereas Na concentrations were depressed only at 3000μg/L. Na(+)/K(+)-ATPase activity was inhibited at both 500 and 3000μg/L in gill 8, but only in 20% SW. Haemolymph K, Mg, and osmolality were unaffected throughout, though all varied with salinity in the expected fashion. These data suggest that Ni impacts ionoregulatory function in the green crab, in a gill- and salinity-dependent manner. Copyright © 2015 Elsevier B.V. All rights reserved.

Effects of DDE on experimentally poisoned free-tailed bats (Tadarida brasiliensis): Lethal brain concentrations

USGS Publications Warehouse

Clark, D.R.; Kroll, J.C.

1977-01-01

Adult female free-tailed bats (Tadarida brasiliensis) were collected at Bracken Cave, Texas, and shipped to the Patuxent Wildlife Research Center. Treated mealworms (Tenebrio molitor) containing 107 ppm DDE were fed to 17 bats; five other bats were fed untreated mealworms. After 40 days on dosage, during which one dosed bat was killed accidentally, four dosed bats were frozen and the remaining 17 were starved to death. The objective was to elevate brain levels of DDE to lethality and measure these concentrations. After the feeding period, dosed bats weighed less than controls. After starvation, the body condition of dosed bats was poorer than that of controls even though there was no difference in the amounts of carcass fat. During starvation, dosed bats lost weight faster than controls. Also, four dosed bats exhibited the prolonged tremoring that characterizes DDE poisoning. DDE increased in brains of starving bats as fat was metabolized. The estimated mean brain concentration of DDE diagnostic of death was 519 ppm with a range of 458-564 ppm. These values resemble diagnostic levels known for two species of passerine birds, but they exceed published levels for two free-tailed bats from Carlsbad Caverns, New Mexico.

Caffeine-Related Deaths: Manner of Deaths and Categories at Risk.

PubMed

Cappelletti, Simone; Piacentino, Daria; Fineschi, Vittorio; Frati, Paola; Cipolloni, Luigi; Aromatario, Mariarosaria

2018-05-14

Caffeine is the most widely consumed psychoactive compound worldwide. It is mostly found in coffee, tea, energizing drinks and in some drugs. However, it has become really easy to obtain pure caffeine (powder or tablets) on the Internet markets. Mechanisms of action are dose-dependent. Serious toxicities such as seizure and cardiac arrhythmias, seen with caffeine plasma concentrations of 15 mg/L or higher, have caused poisoning or, rarely, death; otherwise concentrations of 3⁻6 mg/kg are considered safe. Caffeine concentrations of 80⁻100 mg/L are considered lethal. The aim of this systematic review, performed following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement for the identification and selection of studies, is to review fatal cases in which caffeine has been recognized as the only cause of death in order to identify potential categories at risk. A total of 92 cases have been identified. These events happened more frequently in infants, psychiatric patients, and athletes. Although caffeine intoxication is relatively uncommon, raising awareness about its lethal consequences could be useful for both clinicians and pathologists to identify possible unrecognized cases and prevent related severe health conditions and deaths.

Acaricidal activity of extracts of neem (Azadirachta indica) oil against the larvae of the rabbit mite Sarcoptes scabiei var. cuniculi in vitro.

PubMed

Du, Yong-Hua; Jia, Ren-Yong; Yin, Zhong-Qiong; Pu, Zhong-Hui; Chen, Jiao; Yang, Fan; Zhang, Yu-Qun; Lu, Yang

2008-10-20

The acaricidal activity of the petroleum ether extract, the chloroform extract and the acetic ether extract of neem (Azadirachta indica) oil against Sarcoptes scabiei var. cuniculi larvae was tested in vitro. A complementary log-log (CLL) model was used to analyze the data of the toxicity tests. The results showed that at all test time points, the petroleum ether extract demonstrated the highest activity against the larvae of S. scabiei var. cuniculi, while the activities of the chloroform extract and the acetic ether extract were similar. The activities of both the petroleum ether extract and the chloroform extract against the larvae showed the relation of time and concentration dependent. The median lethal concentration (LC50) of the petroleum ether extract (1.3 microL/mL) was about three times that of the chloroform extract (4.1 microL/mL) at 24 h post-treatment. At the concentrations of 500.0 microL/mL, the median lethal time (LT50) of the petroleum ether extract and the chloroform extract was 8.4 and 9.6 h, respectively.

Insecticides applied to a nursery colony of little brown bats (Myotis lucifugus): lethal concentrations in brain tissues

USGS Publications Warehouse

Clark, D.R.; Kunz, T.H.; Kaiser, T.E.

1978-01-01

-Forty-six Myotis lucifugus were collected in May and June 1974 at a nursery colony in Hillsborough County, New Hampshire, that had been sprayed with DDT and chlordane in August and September 1973. When collected, 27 bats were alive, two were convulsing, and 17 were dead. Brains, carcasses, and milk and masticated insects from stomachs were analyzed for organochlorine insecticides and polychlorinated biphenyls (PCB's). ...Concentrations of chemical residues in brains of surviving bats were compared with those of dead and convulsing bats. These comparisons indicated that DDT was the cause of death. Lethal brain concentrations of DDT in adult females averaged 24.52 parts per million (ppm) and suggested that adult M. lucifugus are approximately twice as sensitive to DDT as are adult laboratory rats and mice. Juvenile bats were about 1.5 times more sensitive than adult bats....Large chemical residues were present in milk. We found a statistically significant relationship between declines in carcass residues in lactating females and uterine regression for six of 10 toxicants. Among juveniles, there were corresponding, significant increases (for nine of 10 toxicants) in carcass levels of residues correlated with increasing age (growth of forearm).

Diverse functions of 24(S)-hydroxycholesterol in the brain.

PubMed

Noguchi, Noriko; Saito, Yoshiro; Urano, Yasuomi

2014-04-11

24(S)-hydroxycholesterol (24S-OHC) which is enzymatically produced in the brain plays important physiological roles in maintaining brain cholesterol homeostasis. We found that 24S-OHC at sub-lethal concentrations down-regulated amyloid precursor protein (APP) trafficking via enhancement of the complex formation of APP with up-regulated glucose-regulated protein 78, an endoplasmic reticulum chaperone. In accordance with this mechanism, 24S-OHC suppressed amyloid-β production in human neuroblastoma SH-SY5Y cells. Furthermore, 24S-OHC at sub-lethal concentrations induced adaptive responses via transcriptional activation of the liver X receptor signaling pathway, thereby protecting neuronal cells against the forthcoming oxidative stress induced by 7-ketocholesterol. On the other hand, we found that high concentrations of 24S-OHC induced apoptosis in T-lymphoma Jurkat cells which endogenously expressed caspase-8, and induced necroptosis - a form of programmed necrosis - in neuronal SH-SY5Y cells which expressed no caspase-8. In this Article, we show the diverse functions of 24S-OHC and consider the possible importance of controlling 24S-OHC levels in the brain for preventing neurodegenerative diseases. Copyright © 2014 Elsevier Inc. All rights reserved.

Caffeine-Related Deaths: Manner of Deaths and Categories at Risk

PubMed Central

Cappelletti, Simone; Piacentino, Daria; Fineschi, Vittorio; Frati, Paola; Cipolloni, Luigi; Aromatario, Mariarosaria

2018-01-01

Caffeine is the most widely consumed psychoactive compound worldwide. It is mostly found in coffee, tea, energizing drinks and in some drugs. However, it has become really easy to obtain pure caffeine (powder or tablets) on the Internet markets. Mechanisms of action are dose-dependent. Serious toxicities such as seizure and cardiac arrhythmias, seen with caffeine plasma concentrations of 15 mg/L or higher, have caused poisoning or, rarely, death; otherwise concentrations of 3–6 mg/kg are considered safe. Caffeine concentrations of 80–100 mg/L are considered lethal. The aim of this systematic review, performed following the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statement for the identification and selection of studies, is to review fatal cases in which caffeine has been recognized as the only cause of death in order to identify potential categories at risk. A total of 92 cases have been identified. These events happened more frequently in infants, psychiatric patients, and athletes. Although caffeine intoxication is relatively uncommon, raising awareness about its lethal consequences could be useful for both clinicians and pathologists to identify possible unrecognized cases and prevent related severe health conditions and deaths. PMID:29757951

The cytotoxic mechanism of karlotoxin 2 (KmTx 2) from Karlodinium veneficum (Dinophyceae)

PubMed Central

Deeds, Jonathan R.; Hoesch, Robert E.; Place, Allen R.; Kao, Joseph P.Y.

2015-01-01

This study demonstrates that the polyketide toxin karlotoxin 2 (KmTx 2) produced by Karlodinium veneficum, a dinoflagellate associated with fish kills in temperate estuaries worldwide, alters vertebrate cell membrane permeability. Microfluorimetric and electrophysiological measurements were used to determine that vertebrate cellular toxicity occurs through non-selective permeabilization of plasma membranes, leading to osmotic cell lysis. Previous studies showed that KmTx 2 is lethal to fish at naturally-occurring concentrations measured during fish kills, while sub-lethal doses severely damage gill epithelia. This study provides a mechanistic explanation for the association between K. veneficum blooms and fish kills that has long been observed in temperate estuaries worldwide. PMID:25546005

Residues of organochlorine pesticides, polychlorinated biphenyls, and mercury and autopsy data for bald eagles, 1969 and 1970

USGS Publications Warehouse

Belisle, Andre A.; Reichel, William L.; Locke, Louis N.; Lamont, Thair; Mulhern, Bernard M.; Prouty, Richard M.; DeWolf, Robert B.; Cromartie, Eugene

1972-01-01

Thirty-nine bald eagles found sick or dead in 13 States during 1969 and 1970 were analyzed for pesticide residues. Residues of DDE, dieldrin, polychlorinated biphenyls (PCB's), and mercury were detected in all bald eagle carcasses; DDD residues were detected in 38; DDT, heptachlor epoxide, and dichlorobenzophenone (DCBP) were detected less frequently. Six eagles contained possible lethal levels of dieldrin in the brain, and one contained a lethal concentration of DDE (385 ppm) in the brain together with 235 ppm of PCB's. Autopsy revealed that 18 bald eagles were illegally shot; other causes of death were impact injuries, electrocution, emaciation, and infectious diseases.

Size dimorphism, molt status, and body mass variation of prairiefalcons nesting in the Snake River Birds of Prey National Conservation Area

USGS Publications Warehouse

Steenhof, Karen; McKinley, J.O.

2006-01-01

Thirty-nine bald eagles found sick or dead in 13 States during 1969 and 1970 were analyzed for pesticide residues. Residues of DDE, dieldrin, polychlorinated biphenyls (PCB's), and mercury were detected in all bald eagle carcasses; DDD residues were detected in 38; DDT, heptachlor epoxide, and dichlorobenzophenone (DCBP) were detected less frequently. Six eagles contained possible lethal levels of dieldrin in the brain, and one contained a lethal concentration of DDE (385 ppm) in the brain together with 235 ppm of PCB's. Autopsy revealed that 18 bald eagles were illegally shot; other causes of death were impact injuries, electrocution, emaciation, and infectious diseases.

The lethal interaction of x ray and penicillin induced lesions following x-irradiation of Escherichia coli B/r in the presence of hypoxic cell sensitizers

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

Gillies, N.E.; Obioha, F.I.

When Escherichia coli B/r were x-irradiated under anoxia in the presence of different electron-affinic sensitizers and then incubated in broth containing penicillin (at a concentration that did not kill unirradiated cells) additional killing of the bacteria occurred provided the sensitizers were of relatively high lipophilicity. The overall effect was to increase the efficiency of these sensitizers. It is concluded that sensitizer-dependent latent radiation lesions(s) are produced in membrane components of the cell envelope that interact with damage caused by penicillin in the peptidoglycan layer and this causes the additional lethality.

Comparative Toxicities of Newer and Conventional Insecticides: Against Four Generalist Predator Species.

PubMed

Prabhaker, Nilima; Naranjo, Steven; Perring, Thomas; Castle, Steven

2017-12-05

Generalist insect predators play an essential role in regulating the populations of Bemisia tabaci and other pests in agricultural systems, but may be affected negatively by insecticides applied for pest management. Evaluation of insecticide compatibility with specific predator species can provide a basis for making treatment decisions with the aim of conserving natural enemies. Eleven insecticides representing six modes of action groups were evaluated for toxicity against four predator species and at different developmental stages. Full-concentration series bioassays were conducted on laboratory-reared or insectary-supplied predators using Petri dish and systemic uptake bioassay techniques. Highest toxicities were observed with imidacloprid and clothianidin against first and second instar nymphs of Geocoris punctipes (Say) (Hemiptera: Geocoridae). Later instar nymphs were less susceptible to neonicotinoid treatments based on higher LC50s observed with imidacloprid, thiamethoxam, and dinotefuran against third or fourth instar nymphs. The pyrethroid insecticide bifenthrin was highly toxic against adults of G. punctipes and Orius insidiosus (Say) (Hemiptera: Anthocoridae). Standard concentration/mortality evaluation of nonacute toxicity insecticides, including buprofezin, pyriproxyfen, spirotetramat, and spiromesifen, was inconclusive in terms of generating probit statistics. However, low mortality levels of insects exposed for up to 120 h suggested minimal lethality with the exception of pyriproxyfen that was mildly toxic to Chrysoperla rufilabris (Burmeister) (Neuroptera: Chrysopidae). Published by Oxford University Press on behalf of Entomological Society of America 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Acute and subchronic toxicity of naturally weathered Exxon Valdez crude oil in mallards and ferrets

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

Stubblefield, W.A.; Hancock, G.A.; Ford, W.H.

1995-11-01

The toxic properties of naturally weathered Exxon Valdez crude oil (WEVC) were assessed in a battery of acute and subchronic toxicity tests using mallards, Anas platyrhynchos, and European ferrets, Mustela putorius. Adult mallard acute oral toxicity study results indicated no mortalities or signs o toxicity, i.e., no-observed-adverse-effect level (NOAEL) and median lethal dose (LD50) > 5,000 mg/kg. Acute oral feeding and food avoidance tests with ducklings also indicated no toxicity (NOAEL and LC50 > 50,000 mg/kg diet) with no evidence of food avoidance (FAC50 > 20,000 mg/kg diet). No mortalities or toxic signs were noted in a 14-d feeding studymore » with adult birds at dietary concentrations up to 100,000 mg WEVC/kg diet. Among clinical and physiological end points evaluated, the only significant difference noted was an increase in liver: body weight ratios in the 100,000-mg WEVC/kg diet dose group. No differences in clinical chemistry or hematological parameters were noted, and there were no consistent differences in histological evaluations of organ tissues. Daily oral doses of up to 5,000 mg/kg of WEVC over 5 d resulted in minimal effects on ferrets. Increased serum albumin concentrations were observed in the 5,000-mg/kg dose group females and decreased spleen weights were noted in females of all WEVC treatment groups. No other significant observations were noted.« less

Effective lethal mutagenesis of influenza virus by three nucleoside analogs.

PubMed

Pauly, Matthew D; Lauring, Adam S

2015-04-01

Lethal mutagenesis is a broad-spectrum antiviral strategy that exploits the high mutation rate and low mutational tolerance of many RNA viruses. This approach uses mutagenic drugs to increase viral mutation rates and burden viral populations with mutations that reduce the number of infectious progeny. We investigated the effectiveness of lethal mutagenesis as a strategy against influenza virus using three nucleoside analogs, ribavirin, 5-azacytidine, and 5-fluorouracil. All three drugs were active against a panel of seasonal H3N2 and laboratory-adapted H1N1 strains. We found that each drug increased the frequency of mutations in influenza virus populations and decreased the virus' specific infectivity, indicating a mutagenic mode of action. We were able to drive viral populations to extinction by passaging influenza virus in the presence of each drug, indicating that complete lethal mutagenesis of influenza virus populations can be achieved when a sufficient mutational burden is applied. Population-wide resistance to these mutagenic agents did not arise after serial passage of influenza virus populations in sublethal concentrations of drug. Sequencing of these drug-passaged viral populations revealed genome-wide accumulation of mutations at low frequency. The replicative capacity of drug-passaged populations was reduced at higher multiplicities of infection, suggesting the presence of defective interfering particles and a possible barrier to the evolution of resistance. Together, our data suggest that lethal mutagenesis may be a particularly effective therapeutic approach with a high genetic barrier to resistance for influenza virus. Influenza virus is an RNA virus that causes significant morbidity and mortality during annual epidemics. Novel therapies for RNA viruses are needed due to the ease with which these viruses evolve resistance to existing therapeutics. Lethal mutagenesis is a broad-spectrum strategy that exploits the high mutation rate and the low mutational tolerance of most RNA viruses. It is thought to possess a higher barrier to resistance than conventional antiviral strategies. We investigated the effectiveness of lethal mutagenesis against influenza virus using three different drugs. We showed that influenza virus was sensitive to lethal mutagenesis by demonstrating that all three drugs induced mutations and led to an increase in the generation of defective viral particles. We also found that it may be difficult for resistance to these drugs to arise at a population-wide level. Our data suggest that lethal mutagenesis may be an attractive anti-influenza strategy that warrants further investigation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

40 CFR 132.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... specified effects in 50 percent of a group of organisms under specified conditions. Endangered or threatened... or Tribe means any Indian Tribe, band, group, or community recognized by the Secretary of the... or graphically estimated concentration that is expected to be lethal to 50 percent of a group of...

Modified host cells with efflux pumps

DOEpatents

Dunlop, Mary J.; Keasling, Jay D.; Mukhopadhyay, Aindrila

2016-08-30

The present invention provides for a modified host cell comprising a heterologous expression of an efflux pump capable of transporting an organic molecule out of the host cell wherein the organic molecule at a sufficiently high concentration reduces the growth rate of or is lethal to the host cell.

Assessment of genetic diversity and bioremediation potential of pseudomonads isolated from pesticide-contaminated artichoke farm soils.

PubMed

Hassen, Wafa; Neifar, Mohamed; Cherif, Hanene; Mahjoubi, Mouna; Souissi, Yasmine; Raddadi, Noura; Fava, Fabio; Cherif, Ameur

2018-06-01

A total of 68 dimethoate and pentachlorophenol-tolerant rhizobacteria, isolated from a pesticide-contaminated agricultural soil, have been identified and typed by means of 16S-23S rRNA internal transcribed spacers analysis (ITS-PCR), 16S rRNA gene sequencing and by repetitive extragenic palindromic (BOX-PCR). The majority of bacterial isolates (84.31%) belonged to Proteobacteria (with a predominance of Gammaproteobacteria, 72.54%), while the remaining isolates were affiliated with Firmicutes (9.80%), Bacteroidetes (1.96%) and Actinobacteria (3.92%). The pesticide-tolerant bacterial isolates belonged to 11 genera, namely Pseudomonas, Bacillus, Acinetobacter, Flavobacterium, Comamonas, Achromobacter, Rhodococcus, Ochrobactrum, Aquamicrobium, Bordetella and Microbacterium . Within the well-represented genus Pseudomonas ( n  = 36), the most common species was Pseudomonas putida ( n  = 32). The efficacy of the selected strain, Pseudomonas putida S148, was further investigated for biodegradation of pentachlorophenol (PCP) in minimal medium, when used as a sole carbon and energy source. At an initial concentration of 100 mg/L, P. putida S148 degraded 91% of PCP after 7 days. GC-MS analyses revealed the formation of tetrachlorohydroquinone, tri- and di-chlorophenols as biodechlorination products in PCP remediation experiments. The toxicity estimation showed that 50% lethal concentration (LC50) and 50% growth inhibition concentration (IGC50) obtained values for the major identified compounds (2,3,4,6 tetrachlorophenol, 2,3,5,6 tetrachlorophenol and tetrachlorohydroquinone) were higher than those estimated for the PCP indicating that the metabolites are less toxic than the original compound for those specific organisms. S148 strain could be added to pesticide-contaminated agricultural soils as a bacterial inoculant for its potential to improve soil quality.

Toxicity of manganese to Ceriodaphnia dubia and Hyalella azteca

USGS Publications Warehouse

Lasier, P.J.; Winger, P.V.; Bogenrieder, K.J.

2000-01-01

Manganese is a toxic element frequently overlooked when assessing toxicity of effluents, sediments and pore waters. Manganese can be present at toxic levels in anoxic solutions due to its increased solubility under chemically-reducing conditions, and it can remain at those levels for days in aerated test waters due to slow precipitation kinetics. Ceriodaphnia dubia and Hyalella azteca are freshwater organisms often used for toxicity testing and recommended for assessments of effluents and pore waters. Lethal and reproductive-inhibition concentrations of Mn were determined for C. dubia in acute 48h tests and chronic 3-brood tests using animals <24 h old and between 24 and 48 h old. Sensitivity of H. azteca was determined with 7d old animals in acute 96h tests. Tests were run at three levels of water hardness to assess the amelioratory effect, which was often significant. Manganese concentrations were measured analytically at test initiation and after 96 h for calculations of toxicity endpoints and determinations of Mn precipitation during the tests. Minimal amounts of Mn (below 3%) precipitated within 96 h. LC50s determined for H. azteca progressively increased from 3.0 to 8.6 to 13.7 mg Mn/L in soft, moderately-hard and hard waters, respectively. The tolerance of C. dubia to Mn was not significantly different between moderately-hard and hard waters, but was significantly lower in soft water. There was no significant difference in Mn sensitivity between the ages of C. dubia tested. Acute LC50 values for C. dubia averaged 6.2, 14.5 and 15.2 mg Mn/L and chronic IC50 values averaged 3.9, 8.5 and 11.5 mg Mn/L for soft, moderately-hard and hard waters, respectively. Manganese toxicity should be considered when assessing solutions with concentrations near these levels.

Physiological effects of waterborne lead exposure in spiny dogfish (Squalus acanthias).

PubMed

Eyckmans, Marleen; Lardon, Isabelle; Wood, Chris M; De Boeck, Gudrun

2013-01-15

To broaden our knowledge about the toxicity of metals in marine elasmobranchs, cannulated spiny dogfish (Squalus acanthias) were exposed to 20 μM and 100 μM lead (Pb). Since we wanted to focus on sub lethal ion-osmoregulatory and respiratory disturbances, arterial blood samples were analysed for pH(a), PaO(2), haematocrit and total CO(2) values at several time points. Plasma was used to determine urea, TMAO, lactate and ion concentrations. After 96 h, Pb concentrations were determined in a number of tissues, such as gill, rectal gland, skin and liver. To further investigate ion and osmoregulation, Na(+)/K(+)-ATPase activities in gill and rectal gland were analysed as well as rates of ammonia and urea excretion. Additionally, we studied the energy reserves in muscle and liver. Pb strongly accumulated in gills and especially in skin. Lower accumulation rates occurred in gut, kidney and rectal gland. A clear disturbance in acid-base status was observed after one day of exposure indicating a transient period of hyperventilation. The increase in pH(a) was temporary at 20 μM, but persisted at 100 μM. After 2 days, plasma Na and Cl concentrations were reduced compared to controls at 100 μM Pb and urea excretion rates were elevated. Pb caused impaired Na(+)/K(+)-ATPase activity in gills, but not in rectal gland. We conclude that spiny dogfish experienced relatively low ion-osmoregulatory and respiratory distress when exposed to lead, particularly when compared to effects of other metals such as silver. These elasmobranchs appear to be able to minimize the disturbance and maintain physiological homeostasis during an acute Pb exposure. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluating the toxic effects of three priority hazardous and noxious substances (HNS) to rotifer Brachionus plicatilis.

PubMed

Zheng, Lei; Pan, Luqing; Lin, Pengfei; Miao, Jingjing; Wang, Xiufen; Lin, Yufei; Wu, Jiangyue

2017-12-01

Hazardous and noxious substances (HNS) spill in the marine environment is an issue of growing concern, and it will mostly continue to do so in the future owing to the increase of high chemical traffic. Nevertheless, the effects of HNS spill on marine environment, especially on aquatic organisms are unclear. Consequently, it is emergent to provide valuable information for the toxicities to marine biota caused by HNS spill. Accordingly, the acute toxicity of three preferential HNS and sub-lethal effects of acrylonitrile on Brachionus plicatilis were evaluated. The median lethal concentration (LC 50 ) at 24 h were 47.2 mg acrylonitrile L -1 , 276.9 mg styrene L -1 , and 488.3 mg p-xylene L -1 , respectively. Sub-lethal toxicity effects of acrylonitrile on feeding behavior, development, and reproduction parameters of B. plicatilis were also evaluated. Results demonstrated that rates of filtration and ingestion were significantly reduced at 2.0, 4.0, and 8.0 mg L -1 of acrylonitrile. Additionally, reproductive period, fecundity, and life span were significantly decreased at high acrylonitrile concentrations. Conversely, juvenile period was significantly increased at the highest two doses and no effects were observed on embryonic development and post-reproductive period. Meanwhile, we found that ingestion rate decline could be a good predictor of reproduction toxicity in B. plicatilis and ecologically relevant endpoint for toxicity assessment. These data will be useful to assess and deal with marine HNS spillages.

Occurrence and mobility of mercury in groundwater: Chapter 5

USGS Publications Warehouse

Barringer, Julia L.; Szabo, Zoltan; Reilly, Pamela A.; Bradley, Paul M.

2013-01-01

Mercury (Hg) has long been identified as an element that is injurious, even lethal, to living organisms. Exposure to its inorganic form, mainly from elemental Hg (Hg(0)) vapor (Fitzgerald & Lamborg, 2007) can cause damage to respiratory, neural, and renal systems (Hutton, 1987; USEPA, 2012; WHO, 2012). The organic form, methylmercury (CH3Hg+; MeHg), is substantially more toxic than the inorganic form (Fitzgerald & Lamborg, 2007). Methylmercury attacks the nervous system and exposure can prove lethal, as demonstrated by well-known incidents such as those in 1956 in Minimata, Japan (Harada, 1995), and 1971 in rural Iraq (Bakir et al., 1973), where, in the former, industrial release of MeHg into coastal waters severely tainted the fish caught and eaten by the local population, and in the latter, grain seed treated with an organic mercurial fungicide was not planted, but eaten in bread instead. Resultant deaths are not known with certainty but have been estimated at about 100 and 500, respectively (Hutton, 1987). Absent such lethal accidents, human exposure to MeHg comes mainly from ingestion of piscivorous fish in which MeHg has accumulated, with potential fetal damage ascribed to high fish diets during their mothers’ pregnancies (USEPA, 2001). Lesser human exposure occurs through ingestion of drinking water (USEPA, 2001), where concentrations of total Hg (THg; inorganic plus organic forms) typically are in the low nanograms-per-liter range[1] - , particularly from many groundwater sources, and concentrations at the microgram-per-liter level are rare.

A meta-analysis synthesizing the effects of pesticides on swim speed and activity of aquatic vertebrates.

PubMed

Shuman-Goodier, Molly E; Propper, Catherine R

2016-09-15

Pesticide contaminants are ubiquitous in aquatic environments and pose a threat to biodiversity. Pesticides also have diverse mechanisms of action that make it difficult to identify impacts on exposed wildlife. Behavioral measures represent an important link between physiological and ecological processes, and are often used to generalize sub-lethal effects of pesticide exposure. In order to bridge the toxicological and behavioral literature, and identify chemical classes that denote the largest threat, we conducted a meta-analysis summarizing the effects of pesticides on swim speed and activity of aquatic vertebrates. We found that exposure to environmentally relevant concentrations of pesticides reduced the swim speed of exposed amphibians and fish by 35%, and reduced overall activity by 72%. There were also differences in the magnitude of this effect across chemical classes, which likely reflect underlying physiological processes. Pyrethroids, carbamates, and organophosphates all produced a large decrease in swim speed, where as phosphonoglycines and triazines showed no overall effect. Pyrethroids, carbamates, organophosphates, organochlorines, and organotins also produced a large decrease in activity, while phosphonoglycines had no overall effect, and triazines had the opposite effect of increasing activity. Our results indicate that even sub-lethal concentrations of pesticides have a strong effect on critical behaviors of aquatic vertebrates, which can affect fitness and alter species interactions. We expect our synthesis can be used to identify chemical classes producing the largest sub-lethal effects for further research and management. Copyright © 2016 Elsevier B.V. All rights reserved.

Sub-lethal activity of small molecules from natural sources and their synthetic derivatives against biofilm forming nosocomial pathogens.

PubMed

Villa, Federica; Villa, Stefania; Gelain, Arianna; Cappitelli, Francesca

2013-01-01

Nowadays, the patient safety is seriously jeopardized by the emergence and spread of nosocomial pathogens in the form of biofilm that is resistant to traditional and affordable antimicrobials. Although advances in organic synthesis have extended the lifetime of classic antibiotics through synthetic modifications, the search of innovative antibiofilm compounds from natural sources can provide new templates, novel targets and unique mechanisms that should have advantages over known antimicrobial agents. Testing sub-lethal concentrations of crude extracts and/or isolated compounds from plants and microorganisms is critical to acting on mechanisms subtler than the killing activity, e.g. those influencing the multicellular behavior, offering an elegant way to develop novel antimicrobial-free antibiofilm strategies. Herein we discussed the search and biological activity of small molecules from natural sources and their synthetic derivatives able to modulate biofilm genesis of nosocomial pathogens through non-microbicidal mechanisms (sub-lethal concentrations). The present work offers an overview about the approaches applied to the discovery of lead small molecules including a) conventional drug design methods like screening of chemical compounds obtained from nature and b) computer- aided drug design approaches. Finally, a classification (not exhaustive but representative) based on the natural origin of small molecules and their synthetic derivatives was reported. The information presented in this review should be of interest to a broad range of disciplines and represents an effort to summarize experimental research and advances in this field.

Linking ciguatera poisoning to spatial ecology of fish: a novel approach to examining the distribution of biotoxin levels in the great barracuda by combining non-lethal blood sampling and biotelemetry.

PubMed

O'Toole, Amanda C; Dechraoui Bottein, Marie-Yasmine; Danylchuk, Andy J; Ramsdell, John S; Cooke, Steven J

2012-06-15

Ciguatera in humans is typically caused by the consumption of reef fish that have accumulated Ciguatoxins (CTXs) in their flesh. Over a six month period, we captured 38 wild adult great barracuda (Sphyraena barracuda), a species commonly associated with ciguatera in The Bahamas. We sampled three tissues (i.e., muscle, liver, and blood) and analysed them for the presence of ciguatoxins using a functional in vitro N2A bioassay. Detectable concentrations of ciguatoxins found in the three tissue types ranged from 2.51 to 211.74pg C-CTX-1 equivalents/g. Blood and liver toxin concentrations were positively correlated (ρ=0.86, P=0.003), indicating that, for the first time, blood sampling provides a non-lethal method of detecting ciguatoxin in wild fish. Non-lethal blood sampling also presents opportunities to couple this approach with biotelemetry and biologging techniques that enable the study of fish distribution and movement. To demonstrate the potential for linking ciguatoxin occurrence with barracuda spatial ecology, we also present a proof-of-concept case study where blood samples were obtained from 20 fish before releasing them with acoustic transmitters and tracking them in the coastal waters using a fixed acoustic telemetry array covering 44km(2). Fish that tested positive for CTX may have smaller home ranges than non-toxic fish (median distance travelled, U=2.21, P=0.03). Results presented from this study may help identify high risk areas and source-sink dynamics of toxins, potentially reducing the incidence and human health risk of ciguatera fish poisoning. Moreover, development of the non-lethal sampling approach and measurement of ciguatera from blood provide future opportunities to understand the mechanistic relationship between toxins and the spatial ecology of a broad range of marine fish species. Copyright © 2012 Elsevier B.V. All rights reserved.

Ingestion of lead from ammunition and lead concentrations in white-tailed sea eagles (Haliaeetus albicilla) in Sweden.

PubMed

Helander, B; Axelsson, J; Borg, H; Holm, K; Bignert, A

2009-10-15

In this study we show for the first time that lead poisoning from ammunition is a significant mortality factor for white-tailed sea eagle (WSE) (Haliaeetus albicilla) in Sweden. We analyzed 118 WSEs collected between 1981 and 2004 from which both liver and kidney samples could be taken. A total of 22% of all eagles examined had elevated (>6 microg/gd.w.) lead concentrations, indicating exposure to leaded ammunition, and 14% of the individuals had either liver or kidney lead concentrations diagnostic of lethal lead poisoning (>20 microg/gd.w.). Lead concentrations in liver and kidney were significantly correlated. In individuals with lead levels <6 microg/g, concentrations were significantly higher in kidney than in liver; in individuals with lead levels >20 microg/g, concentrations were significantly higher in liver. The lead isotope ratios indicate that the source of lead in individuals with lethal concentrations is different from that of individuals exhibiting background concentrations of lead (<6 microg/gd.w.) There were no significant sex or age differences in lead concentrations. A study from the Baltic reported in principle no biomagnification of lead, but background lead concentrations in WSE liver in this study were still four to >10 times higher than concentrations reported for Baltic fish from the same time period. In contrast to other biota there was no decrease in lead concentrations in WSE over the study period. The proportion of lead poisoned WSE remained unchanged over the study period, including two years after a partial ban of lead shot was enforced in 2002 for shallow wetlands. The use of lead in ammunition poses a threat to all raptors potentially feeding on shot game or offal. The removal of offal from shot game and alternatives to leaded ammunition needs to be implemented in order to prevent mortality from lead in raptors and scavengers.

Acute toxicity of two lampricides, 3-trifluoromethyl-4-nitrophenol (TFM) and a TFM: 1% niclosamide mixture, to sea lamprey, three species of unionids, haliplid water beetles, and American eel

USGS Publications Warehouse

Boogaard, Michael A.; Rivera, Jane E.

2011-01-01

We conducted a series of toxicological treatments with 3-trifluoromethyl-4-nitrophenol (TFM) and a TFM:1% 2′,5-dichloro-4′-nitrosalicylanilide (niclosamide) mixture, two compounds used to control larval sea lamprey (Petromyzon marinus) in Great Lakes tributaries, to evaluate the acute toxicity of the lampricides to a number of nontarget species of concern. Treatments were conducted with yellow stage American eel (Anguilla rostrata), adult and larval haliplid water beetles (Haliplus spp.), a surrogate for the endangered Hungerford’s crawling water beetle (Brychius hungerfordi), and adults of three unionid species—giant floater (Pyganadon grandis), fragile papershell (Leptodea fragilis), and pink heelsplitter (Potamilus alatus). Treatments were conducted using a serial dilution system consisting of nine test concentrations and an untreated control with 20% dilution between concentrations. Narcosis was evident among giant floaters exposed to the TFM and the TFM:1% niclosamide mixture and among pink heelsplitters exposed to the TFM:1% niclosamide mixture only but mostly at concentrations greater than 2-fold that required to kill 100% of larval sea lamprey (minimum lethal concentration (MLC)). Tests with the haliplid beetle suggest the risks to the Hungerford’s crawling water beetle associated with TFM applications are minimal. Concentrations over 2-fold the sea lamprey MLC did not kill adult or larval water beetles. Preliminary behavioral observations suggest water beetles may avoid treatment by crawling out of the water. Adult water beetles exposed to TFM at 3-fold the sea lamprey MLC were observed above the water line more often than controls. The lampricide TFM was not acutely toxic to American eel. Mortalities were rare among American eel exposed to TFM concentrations up to 7-fold the observed sea lamprey MLC. Similarly, for the TFM:1% niclosamide mixture, mortalities were rare among American eel exposed to nearly 5-fold the observed sea lamprey MLC. Overall, acute TFM toxicity was not evident among any of the species examined in this study at concentrations targeted to control larval sea lamprey. Results for the adult unionids should be viewed with caution due to the lack of replication in the treatments.

Acute Toxicity of Ternary Cd-Cu-Ni and Cd-Ni-Zn Mixtures to Daphnia magna: Dominant Metal Pairs Change along a Concentration Gradient.

PubMed

Traudt, Elizabeth M; Ranville, James F; Meyer, Joseph S

2017-04-18

Multiple metals are usually present in surface waters, sometimes leading to toxicity that currently is difficult to predict due to potentially non-additive mixture toxicity. Previous toxicity tests with Daphnia magna exposed to binary mixtures of Ni combined with Cd, Cu, or Zn demonstrated that Ni and Zn strongly protect against Cd toxicity, but Cu-Ni toxicity is more than additive, and Ni-Zn toxicity is slightly less than additive. To consider multiple metal-metal interactions, we exposed D. magna neonates to Cd, Cu, Ni, or Zn alone and in ternary Cd-Cu-Ni and Cd-Ni-Zn combinations in standard 48 h lethality tests. In these ternary mixtures, two metals were held constant, while the third metal was varied through a series that ranged from nonlethal to lethal concentrations. In Cd-Cu-Ni mixtures, the toxicity was less than additive, additive, or more than additive, depending on the concentration (or ion activity) of the varied metal and the additivity model (concentration-addition or independent-action) used to predict toxicity. In Cd-Ni-Zn mixtures, the toxicity was less than additive or approximately additive, depending on the concentration (or ion activity) of the varied metal but independent of the additivity model. These results demonstrate that complex interactions of potentially competing toxicity-controlling mechanisms can occur in ternary-metal mixtures but might be predicted by mechanistic bioavailability-based toxicity models.

In situ effects of pesticides on amphibians in the Sierra Nevada.

PubMed

Sparling, Donald W; Bickham, John; Cowman, Deborah; Fellers, Gary M; Lacher, Thomas; Matson, Cole W; McConnell, Laura

2015-03-01

For more than 20 years, conservationists have agreed that amphibian populations around the world are declining. Results obtained through laboratory or mesocosm studies and measurement of contaminant concentrations in areas experiencing declines have supported a role of contaminants in these declines. The current study examines the effects of contaminant exposure to amphibians in situ in areas actually experiencing declines. Early larval Pseudacris regilla were translocated among Lassen Volcanic, Yosemite and Sequoia National Parks, California, USA and caged in wetlands in 2001 and 2002 until metamorphosis. Twenty contaminants were identified in tadpoles with an average of 1.3-5.9 (maximum = 10) contaminants per animal. Sequoia National Park, which had the greatest variety and concentrations of contaminants in 2001, also had tadpoles that experienced the greatest mortality, slowest developmental rates and lowest cholinesterase activities. Yosemite and Sequoia tadpoles and metamorphs had greater genotoxicity than those in Lassen during 2001, as determined by flow cytometry. In 2001 tadpoles at Yosemite had a significantly higher rate of malformations, characterized as hemimelia (shortened femurs), than those at the other two parks but no significant differences were observed in 2002. Fewer differences in contaminant types and concentrations existed among parks during 2002 compared to 2001. In 2002 Sequoia tadpoles had higher mortality and slower developmental rates but there was no difference among parks in cholinesterase activities. Although concentrations of most contaminants were below known lethal concentrations, simultaneous exposure to multiple chemicals and other stressors may have resulted in lethal and sublethal effects.

Anti-dengue efficacy of bioactive andrographolide from Andrographis paniculata (Lamiales: Acanthaceae) against the primary dengue vector Aedes aegypti (Diptera: Culicidae).

PubMed

Edwin, Edward-Sam; Vasantha-Srinivasan, Prabhakaran; Senthil-Nathan, Sengottayan; Thanigaivel, Annamalai; Ponsankar, Athirstam; Pradeepa, Venkatraman; Selin-Rani, Selvaraj; Kalaivani, Kandaswamy; Hunter, Wayne B; Abdel-Megeed, Ahmed; Duraipandiyan, Veeramuthu; Al-Dhabi, Naif Abdullah

2016-11-01

The current study investigated the toxic effect of the leaf extract compound andrographolide from Andrographis paniculata (Burm.f) against the dengue vector Ae. aegypti. GC-MS analysis revealed that andrographolide was recognized as the major chemical constituent with the prominent peak area compared with other compounds. All isolated toxic compounds were purified and confirmed through RP-HPLC against chemical standards. The larvicidal assays established at 25ppm of bioactive compound against the treated instars of Ae. Aegypti showed prominent mortality compared to other treated concentrations. The percent mortality of larvae was directly proportional to concentration. The lethal concentration (LC50) was observed at 12ppm treatment concentration. The bioactive andrographolide considerably reduced the detoxifying enzyme regulations of α- and β- carboxylesterases. In contrast, the levels of GST and CYP450 significantly increase in a dose dependent manner. The andrographolide also showed strong oviposition deterrence effects at the sub-lethal dose of 12ppm. Similarly, the mean number of eggs were also significantly reduced in a dose dependent manner. At the concentration of 12ppm the effective percentage of repellency was greater than 90% with a protection time of 15-210min, compared with control. The histopathology study displayed that larvae treated with bioactive andrographolide had cytopathic effects in the midgut epithelium compared with the control. The present study established that bioactive andrographolide served as a potential useful for dengue vector management. Copyright © 2016 Elsevier B.V. All rights reserved.

A permanent volcanic hazard hiding in diffuse degassing areas

NASA Astrophysics Data System (ADS)

Viveiros, Fátima; Silva, Catarina; Ferreira, Teresa; Pacheco, Joana; Luís Gaspar, João

2017-04-01

Carbon dioxide (CO2) is one of the most abundant volcanic gases and it is released not only during eruptive events, but also during periods of quiescence through fumaroles, springs and soil diffuse degassing areas. In this last case, CO2 is permanently and silently released from the soils and high CO2 concentrations can be measured if the gas accumulates in depressed and non-ventilated areas (such as caves, pits), or even if it enters in buildings. From a public health perspective CO2 is considered an inert asphyxiant gas and may be lethal when present in concentrations higher than 10 vol.%. In the last 30 years several diffuse degassing areas have been identified in different volcanic systems and lethal incidents due to high CO2 concentrations were reported in volcanic environments of Italy (Alban Hills), New Zealand (Rotorua), Cameroon (Lake Nyos and Lake Cameroon), USA (Mammoth Mountain) and Portugal (Azores archipelago). In the Azores volcanic archipelago several villages are located in diffuse degassing areas, where lethal indoor CO2 concentrations (> 20 vol.%) were measured. Recent studies showed that the rate of CO2 emission may change not only during seismo-volcanic unrest, but also due to changes in the meteorological conditions (e.g. barometric pressure, rainfall, wind speed). Few works are available in the literature with permanent monitoring of indoor CO2 in diffuse degassing environments and the monitoring tests are usually applied during a short period of time. This study shows the results of four years (2012-2016) of permanent CO2 monitoring in 12 buildings placed at Caldeiras da Ribeira Grande, an area located in the north flank of Fogo Volcano (São Miguel Island, Azores archipelago), where thermal anomalies and CO2 emissions were detected. CO2 fluxes as high as 20000 g m-2 d-1 are released from the soils and temperature in some sites reaches 100°C. Spike-like and long term variations are observed in the time series recorded by a total of 52 infrared CO2 detectors installed. Results highlight that CO2 can reach hazardous concentrations (> 15 vol.%) due to meteorological changes and show the occurrence of seasonal variations. Different indoor CO2 patterns are displayed depending on the location of the buildings over thermal anomalous zone. Due to its density at standard temperature and pressure, CO2 tends to accumulate in the underground and/or in the ground floor of the buildings, however in the present study higher CO2 concentrations were also measured in the upper floors of some buildings, fact that is correlated with the presence of thermal anomaly. Results obtained based on this robust and continuous monitoring system show once again that indoor CO2 can reach frequently lethal concentrations even in periods of quiescence and that inhabitants of these buildings are exposed to a permanent and quiet hazard, which is detected only through the use of specific instruments. The existence of thermal anomaly associated with the CO2 emission is also responsible for different patterns when compared with the "cold" CO2 degassing areas.

PREDICTING CHRONIC TOXICITY OF CHEMICALS TO FISHES FROM ACUTE TOXICITY TEST DATA: CONCEPT AND LINEAR REGRESSION

EPA Science Inventory

A comprehensive approach to predicting chronic toxicity from acute.toxicity data was developed in which simultaneous consideration is given to concentration, degree of response, and time course of effect. onsistent endpoint (lethality) and degree of response (O%) were used to com...

STATISTICAL APPROACH TO PREDICTING CHRONIC TOXICITY OF CHEMICALS TO FISHES FROM ACUTE TOXICITY TEST DATA

EPA Science Inventory

A comprehensive approach to predicting chronic toxicity from cute toxicity data was developed in which simultaneous onsideration is given to concentration, degree of response, and ime course of effect. onsistent endpoint (lethality) and degree of response (0 percent) were used to...

The Changing Atmosphere: UNEP Environment Brief No. 1.

ERIC Educational Resources Information Center

United Nations Environment Programme, Nairobi (Kenya).

Discussed are the following topics: (1) the greenhouse problem, including the processes involved and some possible resulting scenarios; (2) ozone, the "umbrella" protecting the earth from lethal concentrations of ultraviolet rays and the problem of decreasing ozone levels; (3) what could happen as the earth gets warmer (including…

Laboratory and field evaluation of medicinal plant extracts against filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae)

USDA-ARS?s Scientific Manuscript database

In this study, chemical extracts of Jatropha curcas, Hyptis suaveolens, Abutilon indicum, and Leucas aspera were tested for toxicity to larvae of the filariasis vector Culex quinquefasciatus. Respective median lethal concentrations (LC50) for hexane, chloroform, ethyl acetate, and methanol extracts...

Centrifugal microfluidic platform for ultrasensitive detection of Botulinum Toxin

USDA-ARS?s Scientific Manuscript database

Botulinum neurotoxin – a global public health threat and category A bioterrorism agent - is the most toxic substance known and one of the most challenging toxins to detect due to its lethality at extremely low concentrations. Hence the live-mouse bioassay because of its superior sensitivity, remains...

Mosquitocidal Activity and Mode of Action of the Isoxazoline Fluralaner

USDA-ARS?s Scientific Manuscript database

Mosquitoes, such as Aedes aegypti and Anopheles gambiae, are important vectors of human diseases. Fluralaner, a recently introduced parasiticide, was evaluated as a mosquitocide in this study.On Ae. aegypti and An. gambiae fourth-instar larvae, fluralaner had 24-h LC50 (lethal concentration for 50% ...

Mosquitocidal activity and mode of action of the isoxazoline fluralaner

USDA-ARS?s Scientific Manuscript database

Mosquitoes, such as Aedes aegypti and Anopheles gambiae, are important vectors of human diseases. Fluralaner, a recently introduced parasiticide, was evaluated as a mosquitocide in this study.On Ae. aegypti and An. gambiae fourth-instar larvae, fluralaner had 24-h LC50 (lethal concentration for 50% ...

Toxicity of methanol to fish, crustacean, oligochaete worm, and aquatic ecosystem.

PubMed

Kaviraj, A; Bhunia, F; Saha, N C

2004-01-01

Static renewal bioassays were conducted in the laboratory and in outdoor artificial enclosures to evaluate toxic effects of methanol to one teleost fish and two aquatic invertebrates and to limnological variables of aquatic ecosystem. Ninety-six-hour acute toxicity tests revealed cladoceran crustacea Moina micrura as the most sensitive to methanol (LC50, 4.82 g/L), followed by freshwater teleost Oreochromis mossambicus (LC50, 15.32 g/L) and oligochaete worm Branchiura sowerbyi (LC50, 54.89 g/L). The fish, when exposed to lethal concentrations of methanol, showed difficulties in respiration and swimming. The oligochaete body wrinkled and fragmented under lethal exposure of methanol. Effects of five sublethal concentrations of methanol (0, 23.75, 47.49, 736.10, and 1527.60 mg/L) on the feeding rate of the fish and on its growth and reproduction were evaluated by separate bioassays. Ninety-six-hour bioassays in the laboratory showed significant reduction in the appetite of fish when exposed to 736.10 mg/L or higher concentrations of methanol. Chronic toxicity bioassays (90 days) in outdoor enclosures showed a reduction in growth, maturity index and fecundity of fish at 47.49 mg/L or higher concentrations of methanol. Primary productivity, phytoplankton population, and alkalinity of water were also reduced at these concentrations. Chronic exposure to 1527.60 mg/L methanol resulted in damages of the epithelium of primary and secondary gill lamellae of the fish. The results revealed 23.75 mg/L as the no-observed-effect concentration (NOEC) of methanol to freshwater aquatic ecosystem.

Changes in carbohydrate metabolism in coconut palms infected with the lethal yellowing phytoplasma.

PubMed

Maust, B E; Espadas, F; Talavera, C; Aguilar, M; Santamaría, J M; Oropeza, C

2003-08-01

ABSTRACT Lethal yellowing (LY), a disease caused by a phytoplasma, is the most devastating disease affecting coconut (Cocos nucifera) in Mexico. Thousands of coconut palm trees have died on the Yucatan peninsula while plantations in Central America and on the Pacific coast of Mexico are severely threatened. Polymerase chain reaction assays enable identification of incubating palm trees (stage 0+, phytoplasma detected but palm asymptomatic). With the development of LY, palm trees exhibit various visual symptoms such as premature nut fall (stage 1), inflorescence necrosis (stages 2 to 3), leaf chlorosis and senescence (stages 4 to 6), and finally palm death. However, physiological changes occur in the leaves and roots prior to onset of visual symptoms. Stomatal conductance, photosynthesis, and root respiration decreased in stages 0+ to 6. The number of active photosystem II (PSII) reaction centers decreased during stage 2, but maximum quantum use efficiency of PSII remained similar until stage 3 before declining. Sugar and starch concentrations in intermediate leaves (leaf 14) and upper leaves (leaf 4) increased from stage 0- (healthy) to stages 2 to 4, while root carbohydrate concentrations decreased rapidly from stage 0- to stage 0+ (incubating phytoplasma). Although photosynthetic rates and root carbohydrate concentrations decreased, leaf carbohydrate concentrations increased, suggesting inhibition of sugar transport in the phloem leading to stress in sink tissues and development of visual symptoms of LY.

Temperature-dependent acute toxicity of methomyl pesticide on larvae of 3 Asian amphibian species.

PubMed

Lau, Edward Tak Chuen; Karraker, Nancy Elizabeth; Leung, Kenneth Mei Yee

2015-10-01

Relative to other animal taxa, ecotoxicological studies on amphibians are scarce, even though amphibians are experiencing global declines and pollution has been identified as an important threat. Agricultural lands provide important habitats for many amphibians, but often these lands are contaminated with pesticides. The authors determined the acute toxicity, in terms of 96-h median lethal concentrations, of the carbamate pesticide methomyl on larvae of 3 Asian amphibian species, the Asian common toad (Duttaphrynus melanostictus), the brown tree frog (Polypedates megacephalus), and the marbled pygmy frog (Microhyla pulchra), at 5 different temperatures (15 °C, 20 °C, 25 °C, 30 °C, and 35 °C) to examine the relationships between temperature and toxicity. Significant interspecific variation in methomyl sensitivity and 2 distinct patterns of temperature-dependent toxicity were found. Because high proportions of malformation among the surviving tadpoles were observed, a further test was carried out on the tree frog to determine effect concentrations using malformation as the endpoint. Concentrations as low as 1.4% of the corresponding 96-h median lethal concentrations at 25 °C were sufficient to cause malformation in 50% of the test population. As the toxicity of pesticides may be significantly amplified at higher temperatures, temperature effects should not be overlooked in ecotoxicological studies and derivation of safety limits in environmental risk assessment and management. © 2015 SETAC.

Toxic effects of the neem oil (Azadirachta indica) formulation on the stink bug predator, Podisus nigrispinus (Heteroptera: Pentatomidae)

PubMed Central

Zanuncio, José Cola; Mourão, Sheila Abreu; Martínez, Luis Carlos; Wilcken, Carlos Frederico; Ramalho, Francisco S.; Plata-Rueda, Angelica; Soares, Marcus Alvarenga; Serrão, José Eduardo

2016-01-01

This research investigated the effects of neem oil on mortality, survival and malformations of the non-target stink bug predator, Podisus nigrispinus. Neurotoxic and growth inhibitor insecticides were used to compare the lethal and sublethal effects from neem oil on this predator. Six concentrations of neem oil were topically applied onto nymphs and adults of this predator. The mortality rates of third, fourth, and fifth instar nymphs increased with increasing neem oil concentrations, suggesting low toxicity to P. nigrispinus nymphs. Mortality of adults was low, but with sublethal effects of neem products on this predator. The developmental rate of P. nigrispinus decreased with increasing neem oil concentrations. Longevity of fourth instar nymphs varied from 3.74 to 3.05 d, fifth instar from 5.94 to 4.07 d and adult from 16.5 and 15.7 d with 0.5 and 50% neem doses. Podisus nigrispinus presented malformations and increase with neem oil concentrations. The main malformations occur in wings, scutellum and legs of this predator. The neem oil at high and sub lethal doses cause mortality, inhibits growth and survival and results in anomalies on wings and legs of the non-traget predator P. nigrispinus indicating that its use associated with biological control should be carefully evaluated. PMID:27596436

Acute and chronic toxicity of pesticides on tadpoles of Physalaemus cuvieri (Anura, Leptodactylidae).

PubMed

Wrubleswski, Juliana; Reichert, Francisco Wilson; Galon, Leandro; Hartmann, Paulo Afonso; Hartmann, Marilia Teresinha

2018-04-01

Brazil is the largest consumer of pesticides in the world. However, knowledge on how these pesticides affect wildlife is scarce. Among the vertebrates, amphibians are particularly important in research to assess the impact of pesticides because of the correlation between pesticide and the decline of these species. This study aimed to evaluate the acute and chronic toxicity of commercial formulations of pesticides, i.e., atrazine (herbicide), cypermethrin (insecticide), and tebuconazole (fungicide) in Physalaemus cuvieri tadpoles. Eggs were collected in nature and cultivated under controlled conditions in the laboratory. Toxicity tests were carried out under standard conditions to determine the lethal concentration (LC 50 ) after 96 h of exposure and to determine the effect of sublethal concentrations after 7 days. In addition, we performed swimming activity tests on tadpoles exposed to sublethal concentrations. The lethal concentration (LC 50 ) was 19.69 mg/L for atrazine, 0.24 mg/L for cypermethrin and 0.98 mg/L for tebuconazole. In the acute test, atrazine showed lower toxicity than cypermethrin and tebuconazole for P. cuvieri. Swimming activity was affected at sublethal doses of atrazine and cypermethrin, but was not after exposure to tebuconazole. Cypermethrin was the insecticide that most altered the swimming activity of the individuals tested. The risk evaluation analysis indicated risks for tadpoles exposed to three tested pesticides, specially cypermethrin.

Organochlorine residues and mortality of herons

USGS Publications Warehouse

Ohlendorf, Harry M.; Swineford, Douglas M.; Locke, Louis N.

1981-01-01

Since 1966, 72 herons found dead or moribund in the field have been analyzed for organochlorine chemicals. In addition, 36 herons were obtained through systematic collections, and carcasses were analyzed to determine sublethal exposure to organochlorines. Brains of birds found dead or moribund were analyzed to determine whether the birds had died of organochlorine poisoning. Residues of DDE were found most frequently (96 of 105 carcasses analyzed), PCBs were second (detected in 90 carcasses), and dieldrin and TDE (detected in 37 and 35 carcasses, respectively) were about equal as third and fourth most frequent. Endrin, mirex, toxaphene, and HCB were found least often (8, 9, 9, and 9 carcasses, respectively). At least one organochlorine was found in each carcass, except for six heron chicks found dead in a Maryland heronry. DDE and PCBs were present in highest concentrations; they exceeded 100 ppm in two birds each. Organochlorine concentrations were almost always higher in adult herons than in immature birds. All birds that had hazardous or lethal concentrations in the brain were adults, and most were great blue herons (Ardea herodias). Dieldrin was the chemical most often considered responsible for death. Herons died of suspected DDT and dieldrin poisoning years after the chemicals were banned in the United States. More than 20 percent of the herons found dead or moribund had lethal or hazardous concentrations of organochlorines in the brain.

Viral single-strand DNA induces p53-dependent apoptosis in human embryonic stem cells.

PubMed

Hirsch, Matthew L; Fagan, B Matthew; Dumitru, Raluca; Bower, Jacquelyn J; Yadav, Swati; Porteus, Matthew H; Pevny, Larysa H; Samulski, R Jude

2011-01-01

Human embryonic stem cells (hESCs) are primed for rapid apoptosis following mild forms of genotoxic stress. A natural form of such cellular stress occurs in response to recombinant adeno-associated virus (rAAV) single-strand DNA genomes, which exploit the host DNA damage response for replication and genome persistence. Herein, we discovered a unique DNA damage response induced by rAAV transduction specific to pluripotent hESCs. Within hours following rAAV transduction, host DNA damage signaling was elicited as measured by increased gamma-H2AX, ser15-p53 phosphorylation, and subsequent p53-dependent transcriptional activation. Nucleotide incorporation assays demonstrated that rAAV transduced cells accumulated in early S-phase followed by the induction of apoptosis. This lethal signaling sequalae required p53 in a manner independent of transcriptional induction of Puma, Bax and Bcl-2 and was not evident in cells differentiated towards a neural lineage. Consistent with a lethal DNA damage response induced upon rAAV transduction of hESCs, empty AAV protein capsids demonstrated no toxicity. In contrast, DNA microinjections demonstrated that the minimal AAV origin of replication and, in particular, a 40 nucleotide G-rich tetrad repeat sequence, was sufficient for hESC apoptosis. Our data support a model in which rAAV transduction of hESCs induces a p53-dependent lethal response that is elicited by a telomeric sequence within the AAV origin of replication.

Deficiency of CRTAP in non-lethal recessive osteogenesis imperfecta reduces collagen deposition into matrix.

PubMed

Valli, M; Barnes, A M; Gallanti, A; Cabral, W A; Viglio, S; Weis, M A; Makareeva, E; Eyre, D; Leikin, S; Antoniazzi, F; Marini, J C; Mottes, M

2012-11-01

Deficiency of any component of the ER-resident collagen prolyl 3-hydroxylation complex causes recessive osteogenesis imperfecta (OI). The complex modifies the α1(I)Pro986 residue and contains cartilage-associated protein (CRTAP), prolyl 3-hydroxylase 1 (P3H1) and cyclophilin B (CyPB). Fibroblasts normally secrete about 10% of CRTAP. Most CRTAP mutations cause a null allele and lethal type VII OI. We identified a 7-year-old Egyptian boy with non-lethal type VII OI and investigated the effects of his null CRTAP mutation on collagen biochemistry, the prolyl 3-hydroxylation complex, and collagen in extracellular matrix. The proband is homozygous for an insertion/deletion in CRTAP (c.118_133del16insTACCC). His dermal fibroblasts synthesize fully overmodified type I collagen, and 3-hydroxylate only 5% of α1(I)Pro986. CRTAP transcripts are 10% of control. CRTAP protein is absent from proband cells, with residual P3H1 and normal CyPB levels. Dermal collagen fibril diameters are significantly increased. By immunofluorescence of long-term cultures, we identified a severe deficiency (10-15% of control) of collagen deposited in extracellular matrix, with disorganization of the minimal fibrillar network. Quantitative pulse-chase experiments corroborate deficiency of matrix deposition, rather than increased matrix turnover. We conclude that defects of extracellular matrix, as well as intracellular defects in collagen modification, contribute to the pathology of type VII OI. © 2011 John Wiley & Sons A/S.

Characteristics of individuals who make impulsive suicide attempts.

PubMed

Spokas, Megan; Wenzel, Amy; Brown, Gregory K; Beck, Aaron T

2012-02-01

Previous research has identified only a few variables that have been associated with making an impulsive suicide attempt. The aim of the current study was to compare individuals who made an impulsive suicide attempt with those who made a premeditated attempt on both previously examined and novel characteristics. Participants were classified as making an impulsive or premeditated attempt based on the Suicide Intent Scale (Beck et al., 1974a) and were compared on a number of characteristics relevant to suicidality, psychiatric history, and demographics. Individuals who made an impulsive attempt expected that their attempts would be less lethal; yet the actual lethality of both groups' attempts was similar. Those who made an impulsive attempt were less depressed and hopeless than those who made a premeditated attempt. Participants who made an impulsive attempt were less likely to report a history of childhood sexual abuse and more likely to be diagnosed with an alcohol use disorder than those who made a premeditated attempt. Although the sample size was adequate for bivariate statistics, future studies using larger sample sizes will allow for multivariate analyses of characteristics that differentiate individuals who make impulsive and premeditated attempts. Clinicians should not minimize the significance of impulsive attempts, as they are associated with a similar level of lethality as premeditated attempts. Focusing mainly on depression and hopelessness as indicators of suicide risk has the potential to under-identify those who are at risk for making impulsive attempts. Copyright © 2011 Elsevier B.V. All rights reserved.

Blue light induced reactive oxygen species from flavin mononucleotide and flavin adenine dinucleotide on lethality of HeLa cells.

PubMed

Yang, Ming-Yeh; Chang, Chih-Jui; Chen, Liang-Yü

2017-08-01

Photodynamic therapy (PDT) is a safe and non-invasive treatment for cancers and microbial infections. Various photosensitizers and light sources have been developed for clinical cancer therapies. Flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) are the cofactor of enzymes and are used as photosensitizers in this study. Targeting hypoxia and light-triggering reactive oxygen species (ROS) are experimental strategies for poisoning tumor cells in vitro. HeLa cells are committed to apoptosis when treated with FMN or FAD and exposed to visible blue light (the maximum emitted wavelength of blue light is 462nm). Under blue light irradiation at 3.744J/cm 2 (=0.52mW/cm 2 irradiated for 2h), the minimal lethal dose is 3.125μM and the median lethal doses (LD 50 ) for FMN and FAD are 6.5μM and 7.2μM, respectively. Individual exposure to visible blue light irradiation or riboflavin photosensitizers does not produce cytotoxicity and no side effects are observed in this study. The western blotting results also show that an intrinsic apoptosis pathway is activated by the ROS during photolysis of riboflavin analogues. Blue light triggers the cytotoxicity of riboflavins on HeLa cells in vitro. Based on these results, this is a feasible and efficient of PDT with an intrinsic photosensitizer for cancer research. Copyright © 2017 Elsevier B.V. All rights reserved.

Embryotoxic effects of environmental chemicals: tests with the South African clawed toad (Xenopus laevis)

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

Dumpert, K.

1987-06-01

In the course of the investigations reported below, it was shown that p-chloroaniline has a lethal effect on the embryos of Xenopus laevis at a concentration of 100 ppm and is development inhibiting (teratogenic) at concentrations of 1 and 10 ppm, respectively. In the case of aniline, a significant development-inhibiting effect was observed at a concentration as low as 1 ppm. A toxic effect was caused by concentrations between 30 and 40 ppm during embryogenesis and by concentrations above 40 ppm during larval development. A very conspicuous finding was an inhibiting effect of 20 to 40 ppm aniline on pigmentationmore » during embryogenesis and of a concentration as low as 1 ppm on the body size of the young toads. In the case of potassium dichromate, it was possible to barely detect a weak development-inhibiting effect during embryogenesis but no development-retarding effect during larval development. Toxic effects of potassium dichromate occurred during embryogenesis at concentrations of 5 and 7.5 ppm and during the larval development at concentrations above 10 ppm. Sodium dodecylbenzenesulfonic acid at a concentration of 50 ppm was found to have such a strong embryolethal effect that 80% of the eggs showed no cell division at all and the remaining 20% developed to only the bicellular stage. A teratogenic effect of this substance was not observed. Phenol, too, was found to be toxic at a concentration of 50 ppm; in contrast to sodium dodecylbenzenesulfonic acid, however, it did not show any lethal effect on the embryos but it did on the tadpoles, mainly in the first stages of larval development. Lower concentrations of phenol (5 and 10 ppm) had a nonsignificant inhibiting effect on the growth of the larvae. A teratogenic effect of phenol was not detected.« less

Effect of Emamectin Benzoate on Mortality, Proboscis Extension, Gustation and Reproduction of the Corn Earworm, Helicoverpa zea

PubMed Central

López, Juan D.; Latheef, M. A.; Hoffmann, W. C.

2010-01-01

Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC50 values (95% CL) being 0.718 (0.532–0.878), 0.525 (0.316–0.751), and 0.182 (0.06–0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of eggs and mating frequency of female H. zea. Larval survival to the pupal stage was also significantly reduced by ingestion of emamectin benzoate by female H. zea. These data suggest that emamectin benzoate is a useful toxicant in an attract-and-kill control strategy against H. zea. Field studies are warranted to validate the results reported in this study. PMID:20673074

Effect of emamectin benzoate on mortality, proboscis extension, gustation and reproduction of the corn earworm, Helicoverpa zea.

PubMed

López, Juan D; Latheef, M A; Hoffmann, W C

2010-01-01

Newly emerged corn earworm adults, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) require a carbohydrate source from plant or other exudates and nectars for dispersal and reproduction. Adults actively seek and forage at feeding sites upon eclosion in the habitat of the larval host plant or during dispersal to, or colonization of, a suitable reproductive habitat. This nocturnal behavior of H. zea has potential for exploitation as a pest management strategy for suppression using an adult feeding approach. This approach entails the use of a feeding attractant and stimulant in combination with a toxicant that when ingested by the adult will either reduce fecundity/fertility at sub-lethal dosages or kill the adult. The intent of this study was to assess reproductive inhibition and toxicity of emamectin benzoate on H. zea when ingested by the adults when mixed in ppm active ingredient (wt:vol) with 2.5 M sucrose as a feeding stimulant. Because the mixture has to be ingested to function, the effect of emamectin benzoate was also evaluated at sub-lethal and lethal concentrations on proboscis extension and gustatory response of H. zea in the laboratory. Feral males captured in sex pheromone-baited traps in the field were used for toxicity evaluations because they were readily available and were more representative of the field populations than laboratory-reared adults. Laboratory-reared female moths were used for reproduction effects because it is very difficult to collect newly emerged feral females from the field. Emamectin benzoate was highly toxic to feral H. zea males with LC(50) values (95% CL) being 0.718 (0.532-0.878), 0.525 (0.316-0.751), and 0.182 (0.06-0.294) ppm for 24, 48 and 72 h responses, respectively. Sub-lethal concentrations of emamectin benzoate did not significantly reduce proboscis extension response of feral males and gustatory response of female H. zea. Sublethal concentrations of emamectin benzoate significantly reduced percent larval hatch of eggs and mating frequency of female H. zea. Larval survival to the pupal stage was also significantly reduced by ingestion of emamectin benzoate by female H. zea. These data suggest that emamectin benzoate is a useful toxicant in an attract-and-kill control strategy against H. zea. Field studies are warranted to validate the results reported in this study.

Cytotoxicity assays with fish cells as an alternative to the acute lethality test with fish.

PubMed

Segner, Helmut

2004-10-01

In ecotoxicology, in vitro assays with fish cells are currently applied for mechanistic studies, bioanalytical purposes and toxicity screening. This paper discusses the potential of cytotoxicity assays with fish cells to reduce, refine or replace acute lethality tests using fish. Basal cytotoxicity data obtained with fish cell lines or fish primary cell cultures show a reasonable to good correlation with lethality data from acute toxicity tests, with the exception of compounds that exert a specific mode of toxic action. Basal cytotoxicity data from fish cell lines also correlate well with cytotoxicity data from mammalian cell lines. However, both the piscine and mammalian in vitro assays are clearly less sensitive than the fish test. Therefore, in vivo LC50 values (concentrations of the test compounds that are lethal to 50% of the fish in the experiment within 96 hours) currently cannot be predicted from in vitro values. This in vitro-in vivo difference in sensitivity appears to be true for both fish cell lines and mammalian cell lines. Given the good in vitro-in vivo correlation in toxicity ranking, together with the clear-cut difference in sensitivity, the role of cytotoxicity assays in a tiered alternative testing strategy could be in priority setting in relation to toxic hazard and in the toxicity classification of chemicals and environmental samples.

Lethal and sub-lethal effects of five pesticides used in rice farming on the earthworm Eisenia fetida.

PubMed

Rico, Andreu; Sabater, Consuelo; Castillo, María-Ángeles

2016-05-01

The toxicity of five pesticides typically used in rice farming (trichlorfon, dimethoate, carbendazim, tebuconazole and prochloraz) was evaluated on different lethal and sub-lethal endpoints of the earthworm Eisenia fetida. The evaluated endpoints included: avoidance behaviour after an exposure period of 2 days; and mortality, weight loss, enzymatic activities (cholinesterase, lactate dehydrogenase and alkaline phosphatase) and histopathological effects after an exposure period of 14 days. Carbendazim was found to be highly toxic to E. fetida (LC50=2mg/kg d.w.), significantly reducing earthworm weight and showing an avoidance response at soil concentrations that are close to those predicted in rice-fields and in surrounding ecosystems. The insecticide dimethoate showed a moderate acute toxicity (LC50=28mg/kg d.w.), whereas the rest of tested pesticides showed low toxicity potential (LC50 values above 100mg/kg d.w.). For these pesticides, however, weight loss was identified as a sensitive endpoint, with NOEC values approximately 2 times or lower than the calculated LC10 values. The investigated effects on the enzymatic activities of E. fetida and the observed histopathological alterations (longitudinal and circular muscle lesions, edematous tissues, endothelial degeneration and necrosis) proved to be sensitive biomarkers to monitor pesticide contamination and are proposed as alternative measures to evaluate pesticide risks on agro-ecosystems. Copyright © 2016 Elsevier Inc. All rights reserved.

Long-term hematopoietic stem cell damage in a murine model of the hematopoietic syndrome of the acute radiation syndrome.

PubMed

Chua, Hui Lin; Plett, P Artur; Sampson, Carol H; Joshi, Mandar; Tabbey, Rebeka; Katz, Barry P; MacVittie, Thomas J; Orschell, Christie M

2012-10-01

Residual bone marrow damage (RBMD) persists for years following exposure to radiation and is believed to be due to decreased self-renewal potential of radiation-damaged hematopoietic stem cells (HSC). Current literature has examined primarily sublethal doses of radiation and time points within a few months of exposure. In this study, the authors examined RBMD in mice surviving lethal doses of total body ionizing irradiation (TBI) in a murine model of the Hematopoietic Syndrome of the Acute Radiation Syndrome (H-ARS). Survivors were analyzed at various time points up to 19 mo post-TBI for hematopoietic function. The competitive bone marrow (BM) repopulating potential of 150 purified c-Kit+ Sca-1+ lineage- CD150+ cells (KSLCD150+) remained severely deficient throughout the study compared to KSLCD150+ cells from non-TBI age-matched controls. The minimal engraftment from these TBI HSCs is predominantly myeloid, with minimal production of lymphocytes both in vitro and in vivo. All classes of blood cells as well as BM cellularity were significantly decreased in TBI mice, especially at later time points as mice aged. Primitive BM hematopoietic cells (KSLCD150+) displayed significantly increased cell cycling in TBI mice at all time points, which may be a physiological attempt to maintain HSC numbers in the post-irradiation state. Taken together, these data suggest that the increased cycling among primitive hematopoietic cells in survivors of lethal radiation may contribute to long-term HSC exhaustion and subsequent RBMD, exacerbated by the added insult of aging at later time points.

Effects of UVB radiation on grazing of two cladocerans from high-altitude Andean lakes

PubMed Central

Rejas, Danny

2017-01-01

Climate change and water extraction may result in increased exposition of the biota to ultraviolet-B radiation (UVB) in high-altitude Andean lakes. Although exposition to lethal doses in these lakes is unlikely, sub-lethal UVB doses may have strong impacts in key compartments such as zooplankton. Here, we aimed at determining the effect of sub-lethal UVB doses on filtration rates of two cladoceran species (Daphnia pulicaria and Ceriodaphnia dubia). We firstly estimated the Incipient Limiting Concentration (ILC) and the Gut Passage Time (GPT) for both species. Thereafter we exposed clones of each species to four increasing UVB doses (treatments): i) DUV-0 (Control), ii) DUV-1 (0.02 MJ m2), iii) DUV-2 (0.03 MJ m2) and iv) DUV-3 (0.15 MJ m2); and estimated their filtration rates using fluorescent micro-spheres. Our results suggest that increasing sub-lethal doses of UVB radiation may strongly disturb the structure and functioning of high-altitude Andean lakes. Filtration rates of D. pulicaria were not affected by the lowest dose applied (DUV-1), but decreased by 50% in treatments DUV-2 and DUV-3. Filtration rates for C. dubia were reduced by more than 80% in treatments DUV-1 and DUV-2 and 100% of mortality occurred at the highest UVB dose applied (DUV-3). PMID:28379975

Targeting IL-17A attenuates neonatal sepsis mortality induced by IL-18

PubMed Central

Wynn, James Lawrence; Wilson, Chris S.; Hawiger, Jacek; Scumpia, Philip O.; Marshall, Andrew F.; Liu, Jin-Hua; Zharkikh, Irina; Wong, Hector R.; Lahni, Patrick; Benjamin, John T.; Plosa, Erin J.; Weitkamp, Jörn-Hendrik; Sherwood, Edward R.; Moldawer, Lyle L.; Ungaro, Ricardo; Baker, Henry V.; Lopez, M. Cecilia; McElroy, Steven J.; Colliou, Natacha; Mohamadzadeh, Mansour; Moore, Daniel Jensen

2016-01-01

Interleukin (IL)-18 is an important effector of innate and adaptive immunity, but its expression must also be tightly regulated because it can potentiate lethal systemic inflammation and death. Healthy and septic human neonates demonstrate elevated serum concentrations of IL-18 compared with adults. Thus, we determined the contribution of IL-18 to lethality and its mechanism in a murine model of neonatal sepsis. We find that IL-18–null neonatal mice are highly protected from polymicrobial sepsis, whereas replenishing IL-18 increased lethality to sepsis or endotoxemia. Increased lethality depended on IL-1 receptor 1 (IL-1R1) signaling but not adaptive immunity. In genome-wide analyses of blood mRNA from septic human neonates, expression of the IL-17 receptor emerged as a critical regulatory node. Indeed, IL-18 administration in sepsis increased IL-17A production by murine intestinal γδT cells as well as Ly6G+ myeloid cells, and blocking IL-17A reduced IL-18–potentiated mortality to both neonatal sepsis and endotoxemia. We conclude that IL-17A is a previously unrecognized effector of IL-18–mediated injury in neonatal sepsis and that disruption of the deleterious and tissue-destructive IL-18/IL-1/IL-17A axis represents a novel therapeutic approach to improve outcomes for human neonates with sepsis. PMID:27114524

Nutritional supplement chromium picolinate causes sterility and lethal mutations in Drosophila melanogaster

PubMed Central

Hepburn, Dion D. D.; Xiao, Jiarong; Bindom, Sharell; Vincent, John B.; O'Donnell, Janis

2003-01-01

The nutritional dietary supplement chromium picolinate, [Cr(pic)3], has gained much notoriety as a safe supplement that supposedly promotes fat loss and muscle enhancement in humans. Thus, a significant industry has materialized around the incorporation of [Cr(pic)3] in many sports foods and drinks and a variety of weight loss products. However, in vitro studies have suggested that low levels of [Cr(pic)3] in the presence of biological reducing agents can catalytically generate reactive oxygen species, and recent in vivo studies have detected oxidative damage in rats receiving the supplement. The potential deleterious in vivo effects of this activity were examined by using Drosophila melanogaster. [Cr(pic)3], but not CrCl3, at levels of 260 μg Cr/kg food or less were found to lower the success rate of pupation and eclosion and to arrest development of pupae in a concentration dependent fashion. X-linked lethal analysis indicates that the supplement greatly enhances the rate of appearance of lethal mutations and dominant female sterility. PMID:12649323

Influence of dimethyl dicarbonate on the resistance of Escherichia coli to a combined UV-Heat treatment in apple juice

PubMed Central

Gouma, Maria; Gayán, Elisa; Raso, Javier; Condón, Santiago; Álvarez, Ignacio

2015-01-01

Commercial apple juice inoculated with Escherichia coli was treated with UV-C, heat (55°C) and dimethyl dicarbonate – DMDC (25, 50, and 75 mg/L)-, applied separately and in combination, in order to investigate the possibility of synergistic lethal effects. The inactivation levels resulting from each treatment applied individually for a maximum treatment time of 3.58 min were limited, reaching 1.2, 2.9, and 0.06 log10 reductions for UV, heat, and DMDC (75 mg/L), respectively. However, all the investigated combinations resulted in a synergistic lethal effect, reducing the total treatment time and UV dose, with the synergistic lethal effect being higher when larger concentrations of DMDC were added to the apple juice. The addition of 75 mg/L of DMDC prior to the combined UV-C light treatment at 55°C resulted in 5 log10 reductions after only 1.8 min, reducing the treatment time and UV dose of the combined UV-Heat treatment by 44%. PMID:26042117

Pigeon chest: comparative analysis of surgical techniques in minimal access repair of pectus carinatum (MARPC).

PubMed

Muntean, Ancuta; Stoica, Ionica; Saxena, Amulya K

2018-02-01

After minimally invasive repair for pectus excavatum (MIRPE), similar procedures for pectus carinatum were developed. This study aimed to analyse the various published techniques of minimal access repair for pectus carinatum (MARPC) and compare the outcomes. Literature was reviewed on PubMed with the terms "pectus carinatum", "minimal access repair", "thoracoscopy" and "children". Twelve MARPC techniques that included 13 articles and 140 patients with mean age 15.46 years met the inclusion criteria. Success rate of corrections was n = 125, about 89% in cumulative reports, with seven articles reporting 100%. The complication rate was 39.28%. Since the pectus bar is placed over the sternum and has a large contact area, skin irritation was the most frequent morbidity (n = 20, 14.28%). However, within the complication group (n = 55), wire breakage (n = 21, 38.18%) and bar displacement (n = 10, 18.18%) were the most frequent complications. Twenty-two (15.71%) patients required a second procedure. Recurrences have been reported in four of twelve techniques. There were no lethal outcomes. MARPC techniques are not standardized, as MIRPE are, so comparative analysis is difficult as the only common denominator is minimal access. Surgical morbidity is high in MARPC and affects > 2/3rd patients with about 15% requiring surgery for complication management.

[Effects of applying Sophora alopecuroids extracts and emamectin on the growth, development, and fecundity of diamondback moth plutella xylostella].

PubMed

Yu, Tian-Cong; Luo, Wan-Chun; Ding, Jun; Yan, Lei; Xiao, Ting; Niu, Hong-Tao

2007-12-01

In this paper, the methanol- and water extracts of Sophora alopecuroids were applied respectively with emamectin, to study their effects on the growth, development, and fecundity of diamondback moth Plutella xylostella. The results showed that the oral toxicity of the mixtures to the 3rd larvae of P. xylostella was much higher than that of emamectin, with the medium lethal concentration (LC50) of methanol extract plus emamectin, water extract plus emamectin, and emamectin being 0.19, 0.32 and 0.51 mg L(-1), respectively. The pupated percentage, emergence percentage, and fecundity of P. xylotella were obviously negatively affected after treated the 3rd larvae with sub-lethal dosage of the mixtures and emamectin.

Rewiring the severe acute respiratory syndrome coronavirus (SARS-CoV) transcription circuit: Engineering a recombination-resistant genome

NASA Astrophysics Data System (ADS)

Yount, Boyd; Roberts, Rhonda S.; Lindesmith, Lisa; Baric, Ralph S.

2006-08-01

Live virus vaccines provide significant protection against many detrimental human and animal diseases, but reversion to virulence by mutation and recombination has reduced appeal. Using severe acute respiratory syndrome coronavirus as a model, we engineered a different transcription regulatory circuit and isolated recombinant viruses. The transcription network allowed for efficient expression of the viral transcripts and proteins, and the recombinant viruses replicated to WT levels. Recombinant genomes were then constructed that contained mixtures of the WT and mutant regulatory circuits, reflecting recombinant viruses that might occur in nature. Although viable viruses could readily be isolated from WT and recombinant genomes containing homogeneous transcription circuits, chimeras that contained mixed regulatory networks were invariantly lethal, because viable chimeric viruses were not isolated. Mechanistically, mixed regulatory circuits promoted inefficient subgenomic transcription from inappropriate start sites, resulting in truncated ORFs and effectively minimize viral structural protein expression. Engineering regulatory transcription circuits of intercommunicating alleles successfully introduces genetic traps into a viral genome that are lethal in RNA recombinant progeny viruses. regulation | systems biology | vaccine design

A cardiovascular drug rescues mice from lethal sepsis by selectively attenuating a late-acting proinflammatory mediator, high mobility group box 1.

PubMed

Li, Wei; Li, Jianhua; Ashok, Mala; Wu, Rongqian; Chen, Dazhi; Yang, Lihong; Yang, Huan; Tracey, Kevin J; Wang, Ping; Sama, Andrew E; Wang, Haichao

2007-03-15

The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-gamma) and late (e.g., high mobility group box 1 (HMGB1) protein) proinflammatory cytokines. The recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We found that many steroidal drugs (such as dexamethasone and cortisone) and nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, and indomethacin) failed to influence endotoxin-induced HMGB1 release even at superpharmacological concentrations (up to 10-25 microM). However, several steroid-like pigments (tanshinone I, tanshinone IIA, and cryptotanshinone) of a popular Chinese herb, Danshen (Salvia miltiorrhiza), dose dependently attenuated endotoxin-induced HMGB1 release in macrophage/monocyte cultures. A water-soluble tanshinone IIA sodium sulfonate derivative (TSNIIA-SS), which has been widely used as a Chinese medicine for patients with cardiovascular disorders, selectively abrogated endotoxin-induced HMGB1 cytoplasmic translocation and release in a glucocorticoid receptor-independent manner. Administration of TSNIIA-SS significantly protected mice against lethal endotoxemia and rescued mice from lethal sepsis even when the first dose was given 24 h after the onset of sepsis. The therapeutic effects were partly attributable to attenuation of systemic accumulation of HMGB1 (but not TNF and NO) and improvement of cardiovascular physiologic parameters (e.g., decrease in total peripheral vascular resistance and increase in cardiac stroke volume) in septic animals. Taken together, these data re-enforce the pathogenic role of HMGB1 in lethal sepsis, and support a therapeutic potential for TSNIIA-SS in the treatment of human sepsis.

A Cardiovascular Drug Rescues Mice from Lethal Sepsis by Selectively Attenuating a Late-Acting Proinflammatory Mediator, High Mobility Group Box 11

PubMed Central

Li, Wei; Li, Jianhua; Ashok, Mala; Wu, Rongqian; Chen, Dazhi; Yang, Lihong; Yang, Huan; Tracey, Kevin J.; Wang, Ping; Sama, Andrew E.; Wang, Haichao

2007-01-01

The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-γ) and late (e.g., high mobility group box 1 (HMGB1) protein) proinflammatory cytokines. The recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We found that many steroidal drugs (such as dexamethasone and cortisone) and nonsteroidal anti-inflammatory drugs (such as aspirin, ibuprofen, and indomethacin) failed to influence endotoxin-induced HMGB1 release even at superpharmacological concentrations (up to 10–25 μM). However, several steroid-like pigments (tanshinone I, tanshinone IIA, and cryptotanshinone) of a popular Chinese herb, Danshen (Salvia miltiorrhiza), dose dependently attenuated endotoxin-induced HMGB1 release in macrophage/monocyte cultures. A water-soluble tanshinone IIA sodium sulfonate derivative (TSNIIA-SS), which has been widely used as a Chinese medicine for patients with cardiovascular disorders, selectively abrogated endotoxin-induced HMGB1 cytoplasmic translocation and release in a glucocorticoid receptor-independent manner. Administration of TSNIIA-SS significantly protected mice against lethal endotoxemia and rescued mice from lethal sepsis even when the first dose was given 24 h after the onset of sepsis. The therapeutic effects were partly attributable to attenuation of systemic accumulation of HMGB1 (but not TNF and NO) and improvement of cardiovascular physiologic parameters (e.g., decrease in total peripheral vascular resistance and increase in cardiac stroke volume) in septic animals. Taken together, these data re-enforce the pathogenic role of HMGB1 in lethal sepsis, and support a therapeutic potential for TSNIIA-SS in the treatment of human sepsis. PMID:17339485

Hydrogen peroxide induced by the fungicide prothioconazole triggers deoxynivalenol (DON) production by Fusarium graminearum

PubMed Central

2010-01-01

Background Fusarium head blight is a very important disease of small grain cereals with F. graminearum as one of the most important causal agents. It not only causes reduction in yield and quality but from a human and animal healthcare point of view, it produces mycotoxins such as deoxynivalenol (DON) which can accumulate to toxic levels. Little is known about external triggers influencing DON production. Results In the present work, a combined in vivo/in vitro approach was used to test the effect of sub lethal fungicide treatments on DON production. Using a dilution series of prothioconazole, azoxystrobin and prothioconazole + fluoxastrobin, we demonstrated that sub lethal doses of prothioconazole coincide with an increase in DON production 48 h after fungicide treatment. In an artificial infection trial using wheat plants, the in vitro results of increased DON levels upon sub lethal prothioconazole application were confirmed illustrating the significance of these results from a practical point of view. In addition, further in vitro experiments revealed a timely hyperinduction of H2O2 production as fast as 4 h after amending cultures with prothioconazole. When applying H2O2 directly to germinating conidia, a similar induction of DON-production by F. graminearum was observed. The effect of sub lethal prothioconazole concentrations on DON production completely disappeared when applying catalase together with the fungicide. Conclusions These cumulative results suggest that H2O2 induced by sub lethal doses of the triazole fungicide prothioconazole acts as a trigger of DON biosynthesis. In a broader framework, this work clearly shows that DON production by the plant pathogen F. graminearum is the result of the interaction of fungal genomics and external environmental triggers. PMID:20398299

Combined effects of plant extracts in inhibiting the growth of Bacillus cereus in reconstituted infant rice cereal.

PubMed

Jun, Hyejung; Kim, Jinsol; Bang, Jihyun; Kim, Hoikyung; Beuchat, Larry R; Ryu, Jee-Hoon

2013-01-01

A study was done to determine the potential use of plant extracts to inhibit the growth of Bacillus cereus in reconstituted infant rice cereal. A total of 2116 extracts were screened for inhibitory activity against B. cereus using an agar well diffusion assay. The minimal inhibitory concentrations (MIC) and minimal lethal concentrations (MLC) of 14 promising extracts in tryptic soy broth (TSB) were determined. Dryopteris erythrosora (autumn fern) root extract showed the lowest MIC (0.0156 mg/ml), followed by Siegesbeckia glabrescens (Siegesbeckia herb) leaf (0.0313 mg/ml), Morus alba (white mulberry) cortex (0.0313 mg/ml), Carex pumila (sand sedge) root (0.0625 mg/ml), and Citrus paradisi (grapefruit) seed (0.0625 mg/ml) extracts. The order of MLCs of extracts was D. erythrosora root (0.0156 mg/ml)

Acute toxicity tests and meta-analysis identify gaps in tropical ecotoxicology for amphibians.

PubMed

Ghose, Sonia L; Donnelly, Maureen A; Kerby, Jacob; Whitfield, Steven M

2014-09-01

Amphibian populations are declining worldwide, particularly in tropical regions where amphibian diversity is highest. Pollutants, including agricultural pesticides, have been identified as a potential contributor to decline, yet toxicological studies of tropical amphibians are very rare. The present study assesses toxic effects on amphibians of 10 commonly used commercial pesticides in tropical agriculture using 2 approaches. First, the authors conducted 8-d toxicity assays with formulations of each pesticide using individually reared red-eyed tree frog (Agalychnis callidryas) tadpoles. Second, they conducted a review of available data for the lethal concentration to kill 50% of test animals from the US Environmental Protection Agency's ECOTOX database to allow comparison with their findings. Lethal concentration estimates from the assays ranged over several orders of magnitude. The nematicides terbufos and ethoprophos and the fungicide chlorothalonil were very highly toxic, with evident effects within an order of magnitude of environmental concentrations. Acute toxicity assays and meta-analysis show that nematicides and fungicides are generally more toxic than herbicides yet receive far less research attention than less toxic herbicides. Given that the tropics have a high diversity of amphibians, the findings emphasize the need for research into the effects of commonly used pesticides in tropical countries and should help guide future ecotoxicological research in tropical regions. © 2014 SETAC.

Susceptibility of northern corn rootworm Diabrotica barberi (Coleoptera: Chrysomelidae) to mCry3A and eCry3.1Ab Bacillus thuringiensis proteins.

PubMed

Oyediran, Isaac O; Matthews, Phillip; Palekar, Narendra; French, Wade; Conville, Jared; Burd, Tony

2016-12-01

The susceptibility of the northern corn rootworm Diabrotica barberi (Smith & Lawrence) to mCry3A and eCry3.1Ab proteins derived from Bacillus thuringiensis (Bt) was determined using a diet bioassay. Northern corn rootworm neonates were exposed to different concentrations of mCry3A and eCry3.1Ab, incorporated into artificial diet. Larval mortality was evaluated after 7 d. The mCry3A and eCry3.1Ab proteins were found to be toxic to the northern corn rootworm larvae. The LC 50 and LC 99 values for mCry3A were 5.13 and 2482.31 μg/mL, respectively. For eCry3.1Ab, the LC 50 and LC 99 values were 0.49 and 213.01 μg/mL. Based on the estimated lethal concentrations, eCry3.1Ab protein was more efficacious to northern corn rootworm larvae than mCry3A. These lethal concentration values will be used as diagnostic doses for routine annual monitoring for change in susceptibility of field collected northern corn rootworm to mCry3A, and eCry3.1Ab toxins. © 2015 Institute of Zoology, Chinese Academy of Sciences.

Toxicity of synthetic musks to early life stages of the freshwater mussel Lampsilis cardium

USGS Publications Warehouse

Gooding, M.P.; Newton, T.J.; Bartsch, M.R.; Hornbuckle, K.C.

2006-01-01

Polycyclic musk fragrances are common additives to many consumer products. As a result of their widespread use and slow degradation rates, they are widely found in aquatic environments. This study reports on the lethal and sublethal toxicity of the polycyclic musks AHTN (Tonalide??) and HHCB (Galaxolide??) to glochidial (larval) and juvenile life stages of the freshwater mussel Lampsilis cardium (Rafinesque, 1820). In glochidia, 24-h median lethal concentrations (LC50s) ranged from 454 to 850 ??g AHTN/L and from 1000 to >1750 ??g HHCB/L (water solubility). Results for 48-h tests were similar to the 24-h tests. In 96-h tests with juveniles, we did not observe a dose-response relation between mortality and either musk. However, the growth rate was reduced by musk exposure. The median effective concentrations (EC50s, based on growth) were highly variable and ranged from 108 to 1034 ??g AHTN/L and 153 to 831 ??g HHCB/L. While all adverse effects occurred at concentrations that are much greater than those reported in natural waters (low ??g/L to ng/L), these results indicate the potential for adverse effects on these long-lived organisms from exposure to synthetic musk fragrances. ?? 2006 Springer Science+Business Media, Inc.

Toxicity of Synthetic Musks to Early Life Stages of the Freshwater Mussel Lampsilis cardium

PubMed Central

Gooding, M.P.; Newton, T.J.; Bartsch, M.R.; Hornbuckle, K.C.

2009-01-01

Polycyclic musk fragrances are common additives to many consumer products. As a result of their widespread use and slow degradation rates, they are widely found in aquatic environments. This study reports on the lethal and sublethal toxicity of the polycyclic musks AHTN (Tonalide®) and HHCB (Galaxolide®) to glochidial (larval) and juvenile life stages of the freshwater mussel Lampsilis cardium (Rafinesque, 1820). In glochidia, 24-h median lethal concentrations (LC50s) ranged from 454 to 850 μg AHTN/L and from 1000 to >1750 μg HHCB/L (water solubility). Results for 48-h tests were similar to the 24-h tests. In 96-h tests with juveniles, we did not observe a dose-response relation between mortality and either musk. However, growth rate was reduced by musk exposure. The median effective concentrations (EC50s, based on growth) were highly variable and ranged from 108 to 1034 μg AHTN/L and 153 to 831 μg HHCB/L. While all adverse effects occurred at concentrations that are much greater than those reported in natural waters (low μg/L to ng/L), these results indicate the potential for adverse effects on these long-lived organisms from exposure to synthetic musk fragrances. PMID:16944041

Viper and Cobra Venom Neutralization by Alginate Coated Multicomponent Polyvalent Antivenom Administered by the Oral Route

PubMed Central

Bhattacharya, Sourav; Chakraborty, Mousumi; Mukhopadhyay, Piyasi; Kundu, P. P.; Mishra, Roshnara

2014-01-01

Background Snake bite causes greater mortality than most of the other neglected tropical diseases. Snake antivenom, although effective in minimizing mortality in developed countries, is not equally so in developing countries due to its poor availability in remote snake infested areas as, and when, required. An alternative approach in this direction could be taken by making orally deliverable polyvalent antivenom formulation, preferably under a globally integrated strategy, for using it as a first aid during transit time from remote trauma sites to hospitals. Methodology/Principal Findings To address this problem, multiple components of polyvalent antivenom were entrapped in alginate. Structural analysis, scanning electron microscopy, entrapment efficiency, loading capacity, swelling study, in vitro pH sensitive release, acid digestion, mucoadhesive property and venom neutralization were studied in in vitro and in vivo models. Results showed that alginate retained its mucoadhesive, acid protective and pH sensitive swelling property after entrapping antivenom. After pH dependent release from alginate beads, antivenom (ASVS) significantly neutralized phospholipaseA2 activity, hemolysis, lactate dehydrogenase activity and lethality of venom. In ex vivo mice intestinal preparation, ASVS was absorbed significantly through the intestine and it inhibited venom lethality which indicated that all the components of antivenom required for neutralization of venom lethality were retained despite absorption across the intestinal layer. Results from in vivo studies indicated that orally delivered ASVS can significantly neutralize venom effects, depicted by protection against lethality, decreased hemotoxicity and renal toxicity caused by russell viper venom. Conclusions/Significance Alginate was effective in entrapping all the structural components of ASVS, which on release and intestinal absorption effectively reconstituted the function of antivenom in neutralizing viper and cobra venom. Further research in this direction can strategize to counter such dilemma in snake bite management by promoting control release and oral antivenom rendered as a first aid. PMID:25102172

Pathways to Late-Life Suicidal Behavior: Cluster Analysis and Predictive Validation of Suicidal Behavior in a Sample of Older Adults With Major Depression.

PubMed

Szanto, Katalin; Galfalvy, Hanga; Vanyukov, Polina M; Keilp, John G; Dombrovski, Alexandre Y

Clinical heterogeneity is a key challenge to understanding suicidal risk, as different pathways to suicidal behavior are likely to exist. We aimed to identify such pathways by uncovering latent classes of late-life depression cases and relating them to prior and future suicidal behavior. Data were collected from June 2010 to September 2015. In this longitudinal study we examined distinct associations of clinical and cognitive/decision-making factors with suicidal behavior in 194 older (50+ years) nondemented, depressed patients; 57 nonpsychiatric healthy controls provided benchmark data. The DSM-IV was used to establish diagnostic criteria. We identified multivariate patterns of risk factors, defining clusters based on personality traits, perceived social support, cognitive performance, and decision-making in an analysis blinded to participants' history of suicidal behavior. We validated these clusters using past and prospective suicidal ideation and behavior. Of 5 clusters identified, 3 were associated with high risk for suicidal behavior: (1) cognitive deficits, dysfunctional personality, low social support, high willingness to delay future rewards, and overrepresentation of high-lethality attempters; (2) high-personality pathology (ie, low self-esteem), minimal or no cognitive deficits, and overrepresentation of low-lethality attempters and ideators; (3) cognitive deficits, inability to delay future rewards, and similar distribution of high- and low-lethality attempters. There were significant between-cluster differences in number (P < .001) and lethality (P = .002) of past suicide attempts and in the likelihood of future suicide attempts (P = .010, 30 attempts by 22 patients, 2 fatal) and emergency psychiatric hospitalizations to prevent suicide (P = .005, 31 participants). Three pathways to suicidal behavior in older patients were found, marked by (1) very high levels of cognitive and dispositional risk factors suggesting a dementia prodrome, (2) dysfunctional personality traits, and (3) impulsive decision-making and cognitive deficits. © Copyright 2018 Physicians Postgraduate Press, Inc.

Immune Protection against Lethal Fungal-Bacterial Intra-Abdominal Infections

PubMed Central

Lilly, Elizabeth A.; Ikeh, Melanie; Nash, Evelyn E.; Fidel, Paul L.

2018-01-01

ABSTRACT Polymicrobial intra-abdominal infections (IAIs) are clinically prevalent and cause significant morbidity and mortality, especially those involving fungi. Our laboratory developed a mouse model of IAI and demonstrated that intraperitoneal inoculation with Candida albicans or other virulent non-albicans Candida (NAC) species plus Staphylococcus aureus resulted in 70 to 80% mortality in 48 to 72 h due to robust local and systemic inflammation (sepsis). Surprisingly, inoculation with Candida dubliniensis or Candida glabrata with S. aureus resulted in minimal mortality, and rechallenge of these mice with lethal C. albicans/S. aureus (i.e., coninfection) resulted in >90% protection. The purpose of this study was to define requirements for C. dubliniensis/S. aureus-mediated protection and interrogate the mechanism of the protective response. Protection was conferred by C. dubliniensis alone or by killed C. dubliniensis plus live S. aureus. S. aureus alone was not protective, and killed S. aureus compromised C. dubliniensis-induced protection. C. dubliniensis/S. aureus also protected against lethal challenge by NAC plus S. aureus and could protect for a long-term duration (60 days between primary challenge and C. albicans/S. aureus rechallenge). Unexpectedly, mice deficient in T and B cells (Rag-1 knockouts [KO]) survived both the initial C. dubliniensis/S. aureus challenge and the C. albicans/S. aureus rechallenge, indicating that adaptive immunity did not play a role. Similarly, mice depleted of macrophages prior to rechallenge were also protected. In contrast, protection was associated with high numbers of Gr-1hi polymorphonuclear leukocytes (PMNLs) in peritoneal lavage fluid within 4 h of rechallenge, and in vivo depletion of Gr-1+ cells prior to rechallenge abrogated protection. These results suggest that Candida species can induce protection against a lethal C. albicans/S. aureus IAI that is mediated by PMNLs and postulated to be a unique form of trained innate immunity. PMID:29339423

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

EPA Science Inventory

This study was designed to define the degree of concentration addition found for mixtures of certain xenobiotics that are thought to act through a similar or different mode of toxic action for the acute mortality and sublethal growth toxicity endpoints, and for a freshwater fish ...

Mosquitocidal and water purification properties of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus leaf extracts.

USDA-ARS?s Scientific Manuscript database

Ethanolic extracts of Cynodon dactylon, Aloe vera, Hemidesmus indicus and Coleus amboinicus were tested for toxicity to 3rd instar Anopheles stephensi, Culex quinquefasciatus, and Aedes aegypti. Median lethal concentrations (LC50) were, respectively, 0.44%, 0.51%, 0.59% and 0.68%. Cynodon dactylon...

Responses of honey bees to lethal and sublethal doses of formulated clothianidin alone and mixtures

USDA-ARS?s Scientific Manuscript database

The widespread use of neonicotinoid insecticides has inevitably sparked concern over the toxicity risk to honey bees. In this study, feeding treatments with the clothianidin formulation Belay® at 2.6 ppb (residue concentration) or its binary mixtures with 5 representative pesticides (classes) did no...

Antimicrobial Peptide-PNA Conjugates Selectively Targeting Bacterial Genes

DTIC Science & Technology

2013-07-22

RXR)4XB and (KFF)3K, were previously reported as a potent permeabilizer against E. coli and MRSA cells (Mellbye, 2009). (RW)4D, a small dendrimeric ...lethal concentration (Liu, 2007). Scheme 1. Synthesis of PNA- dendrimer conjugate. (a) (RW)4D-cysteine (b)Free PNA (C) PNA-(RW)4D conjugates

Low, medium and high heat tolerant strains of Listeria monocytogenes and increased heat stress resistance after exposure to sublethal heat

USDA-ARS?s Scientific Manuscript database

Listeria monocytogenes exhibits sophisticated adaptive mechanisms to counteract higher levels of lethal acid, heat, salt or oxidative stresses after pre-exposure to sublethal concentrations of homogenous stress. A group of 37 strains representing all 13 serotypes of Listeria monocytogenes with initi...

MEASUREMENT OF MECURY IN FISH SCALES AS AN ASSESSMENT METHOD FOR PREDICTING MUSCLE TISSUE MERCURY CNOCENTRATIONS IN LARGEMOUTH BASS

EPA Science Inventory

The relationship between total mercury (Hg) concentration in fish scales and in tissues of largemouth bass (Micropterus salmoides) from 20 freshwater sites was developed and evaluated to determine whether scale analysis would allow a non lethal and convenient method for predicti...

Larvicidal and repellent activity of Vetiveria zizaniodes (Poaceae) essential oil against the malaria vector Anopheles stephensi (Liston) (Diptera: Culicidae)

USDA-ARS?s Scientific Manuscript database

Essential oil extracted by steam distillation of Vetiveria zizanioides (L.) Nash (Poaceae) was evaluated for larvicidal and adult repellent activity against the malaria vector Anopheles stephensi (Liston). Median lethal concentrations (LC50) at 24 h post treatment for instars 1-4 were, respectively,...

Effect of different concentrations of hypertonic saline at different times on protoscoleces of hydatid cyst isolated from liver and lung.

PubMed

Tappeh, Khosrow Hazreti; Einshaei, Ali; Mahmudloo, Rahim; Mohammadzadeh, Habib; Tahermaram, Mansoor; Mousavi, Seyed Javad

2011-01-01

Most surgeons inject scoloidal materials into the cyst before or after its removal, since any contamination to normal sites will cause re-growth of the same cyst. The aim of this study was to determine the lethal effect of hypertonic saline at different doses and different times on protoscolexes of lung and liver. The livers and lungs of killed animals with hydatid cyst disease were gathered from Urmia Industrial Abattoirs. They were transferred to the university parasitological lab immediately. The hydatid cyst fluid was aspirated with a 10 mm syringe and poured into a 15 cc tubes. The movement of protoscoleces and staining with 0.1% eosin was the test to determine viability of protoscoleces. Those with color absorption were those which were not viable. Different concentrations of hypertonic saline were given at different time. The results showed that in 20% of hypertonic saline in the 4th minute, 80% of protoscoleces were alive while in the 5th minute 50% were alive, in the 7th minute 20% and 8th minute 5%, 9th minute all of them were dead. In the 10% concentration, at up to 9 minutes 50% were alive, in the 18th minute 20% and in 30 minutes 10% of protoscoleces were alive. In the 5% concentration at up to 10 minutes 90% were alive while in the 22nd minute 80% and in 30 minutes 70% of protoscoleces were alive. When we inject 20% hypertonic saline into the cyst cavity there is aprobability that the cyst contaminates the bile duct and liver through the small hole we made. This material may cause widespread necrosis of the liver. We should use 10% hypertonic saline minimally for 45 minute before surgery and after cyst removal, since the hypertonic saline itself may cause injury to the biliary system.

Effects of the anti-fouling herbicide Irgarol 1051 on two life stages of the grass shrimp, Palaemonetes pugio.

PubMed

Key, Peter B; Chung, Katy W; Hoguet, Jennifer; Sapozhnikova, Yelena; Fulton, Michael H

2008-01-01

This study investigated lethal and sublethal effects (glutathione, lipid peroxidation, cholesterol, and acetylcholinesterase) of the anti-fouling herbicide Irgarol 1051 on larval and adult grass shrimp (Palaemonetes pugio). The 96-hour LC50 test for larvae resulted in an estimated LC50 of 1.52 mg/L (95% confidence interval [CI] 1.26-1.85 mg/L). The adult 96-h LC50 was 2.46 mg/L (95% CI = 2.07-2.93 mg/L). Glutathione, lipid peroxidation, cholesterol and acetylcholinesterase levels were not significantly affected in adult grass shrimp by exposure of up to 3.00 mg/L irgarol. Lipid peroxidation and acetylcholinesterase levels in the larvae were significantly higher than controls in the highest irgarol exposures of 1.0 and 2.0 mg/L, respectively. Cholesterol levels were significantly reduced in larvae in all four irgarol concentrations tested while glutathione levels were not significantly affected in larvae. Both lethal and sublethal effects associated with irgarol exposure were only observed at concentrations well above those reported in the environment.

Evaluation in zebrafish model of the toxicity of rhodamine B-conjugated crotamine, a peptide potentially useful for diagnostics and therapeutics.

PubMed

Chan, Judy Yuet-Wa; Zhou, Hefeng; Kwan, Yiu Wa; Chan, Shun Wan; Radis-Baptista, Gandhi; Lee, Simon Ming-Yuen

2017-11-01

Crotamine is defensin-like cationic peptide from rattlesnake venom that possesses anticancer, antimicrobial, and antifungal properties. Despite these promising biological activities, toxicity is a major concern associated with the development of venom-derived peptides as therapeutic agents. In the present study, we used zebrafish as a system model to evaluate the toxicity of rhodamine B-conjugated (RhoB) crotamine derivative. The lethal toxic concentration of RhoB-crotamine was as low as 4 μM, which effectively kill zebrafish larvae in less than 10 min. With non-lethal concentrations (<1 μM), crotamine caused malformation in zebrafish embryos, delayed or completely halted hatching, adversely affected embryonic developmental programming, decreased the cardiac functions, and attenuated the swimming distance of zebrafish. The RhoB-crotamine translocated across vitelline membrane and accumulated in zebrafish yolk sac. These results demonstrate the sensitive responsivity of zebrafish to trial crotamine analogues for the development of novel therapeutic peptides with improved safety, bioavailability, and efficacy profiles. © 2017 Wiley Periodicals, Inc.

Laboratory evaluation of Vectobac as against Aedes aegypti in Monterrey, Nuevo León, Mexico.

PubMed

Ponce G, Gustavo; Flores, Adriana E; Badii, Mohammad H; Rodríguez-Tovar, M Luisa; Fernández-Salas, Ildefonso

2002-12-01

Intensive use of the organophosphate insecticide malathion against adults and temephos against larvae of Aedes aegypti in Mexico over the past 30 years has led to problems requiring the use of new larvicides. Toward this objective, Bacillus thuringiensis var. israelensis (Bti), a target-specific and environmentally safer control agent, was evaluated. Laboratory bioassays were done to determine the susceptibility of 2nd- and 3rd-stage larvae of Ae. aegypti to Vectobac 12 AS (aqueous suspension, 600 ITU/mg). A median lethal concentration of 0.0104 ppm and a 95% lethal concentration of 0.18 ppm were determined after 24 h of exposure to the agent. The values obtained were adjusted for field application and were further tested in the field by the State of Nuevo León, Mexico Vector Control Program. Suspensions of Bti were poured into pipe-water trucks and transferred to domestic 200-gal metal water drums. Larval populations were reduced during a 2-week study period. However, residents complained about a fine dusty film on the water surface. Nevertheless, these results are promising for future Bti field applications.

Physiological responses of fathead minnow larvae to rice pesticides.

PubMed

Heath, A G; Cech, J J; Brink, L; Moberg, P; Zinkl, J G

1997-08-01

Newly hatched fathead minnow (Pimephales promelas) larvae were exposed for 4 days to two pesticides and ambient receiving waters to simulate conditions in the Sacramento River, California, during the striped bass spawning season which coincides with pesticide use in adjacent rice culture. Carbofuran and molinate were tested at two concentrations: a higher level approximating one-half the LC50 and a level much lower that is similar to that seen in the receiving waters of Colusa Basin Drain. Physiological measurements were made immediately after the exposures and again after a 10-day recovery period in noncontaminated waters. These included growth rate, swimming capacity, response to a mild electric shock, upper and lower lethal temperatures, and activity of acetylcholinesterase in whole-body homogenates. The higher concentrations of carbofuran and molinate caused reductions in swimming capacity, an increased sensitivity to the electric shock, and a reduction in upper lethal temperature. Acetylcholinesterase was reduced in those larvae exposed to the higher levels of carbofuran. In general, the lower levels of pesticide exposure caused no measureable effects nor did exposure to water from Colusa Basin Drain.

Bioavailability of chlorantraniliprole and indoxacarb to eastern subterranean termites (Isoptera: Rhinotermitidae) in various soils.

PubMed

Spomer, Neil A; Kamble, Shripat T; Siegfried, Blair D

2009-10-01

A laboratory study was conducted to determine the toxicity of indoxacarb and chlorantraniliprole to Eastern subterranean termites, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) resulting from topical applications and exposure to treated soil. Soils with varying organic matter (0.57-3.64%) and chemical characteristics were used in termiticide bioassays. Lethal dose resulting from topical application indicated that chlorantraniliprole was two- to 11-fold more toxic than indoxacarb. Lethal concentration assays yielded opposite results where concentrations of indoxacarb in soil that caused either 50 or 90% mortality of R. flavipes workers at 48 and 144 h were two- to six-fold lower than chlorantraniliprole. The bioavailability of indoxacarb and chlorantraniliprole was negatively correlated with soil organic matter. Our results suggest that indoxacarb is more bioavailable to termites in soil than chlorantraniliprole based on calculated bioavailability ratios. However, how these laboratory results correlate to actual field application data and termite efficacy is unknown, and more research is needed. These compounds seem to have excellent activity on termites and have potential to provide new modes of action and new chemistry as liquid termiticides.

Lethal and sub-lethal effects of Deepwater Horizon slick oil and dispersant on oyster (Crassostrea virginica) larvae.

PubMed

Vignier, J; Soudant, P; Chu, F L E; Morris, J M; Carney, M W; Lay, C R; Krasnec, M O; Robert, R; Volety, A K

2016-09-01

In April 2010, crude oil was spilled from the Deepwater Horizon (DWH) oil platform for 87 days, coincident with the spawning season and recruitment of the oyster, Crassostrea virginica, in the Gulf of Mexico. Impacts of acute exposures to surface-collected DWH oil (HEWAF), dispersed oil (CEWAF) and dispersant alone (Corexit 9500A(®)) on planktonic larval stages of C. virginica (veliger, umbo and pediveliger) were tested in the laboratory. Exposures to HEWAF, CEWAF and dispersant were toxic to larvae impairing growth, settlement success and ultimately survival. Larval growth and settlement were reduced at concentrations of tPAH50 ranging from 1.7 to 106 μg L(-1) for HEWAF and 1.1-35 μg L(-1) for CEWAF, concentrations well within the range of water sampled during the DWH oil spill. Sublethal effects induced by oil and dispersant could have significant ecological implications on oyster populations and on the whole estuarine ecosystem. Copyright © 2016 Elsevier Ltd. All rights reserved.

In vitro susceptibility of spiroplasmas to heavy-metal salts.

PubMed

Whitmore, S C; Rissler, J F; Davis, R E

1983-01-01

The susceptibility of six spiroplasma strains to heavy-metal salt was characterized in terms of minimal inhibitory concentrations and minimal biocidal concentrations in broth tube dilution tests. The strains were most susceptible to mercuric chloride and silver nitrate; less susceptible to copper sulfate, cobalt chloride, lead nitrate, and cadmium sulfate; and least susceptible to nickel chloride and zinc sulfate. Spiroplasma citri strains Maroc R8A2 and C189 were the most susceptible to five of eight heavy-metal salts, and honeybee spiroplasma strain AS576 and Spiroplasma floricola strain 23-6 were generally the least susceptible. The difference between the minimal biocidal concentrations and the minimal inhibitory concentrations was greater for certain heavy-metal salts than for others.

Are High-Lethality Suicide Attempters With Bipolar Disorder a Distinct Phenotype?

PubMed Central

Oquendo, Maria A.; Carballo, Juan Jose; Rajouria, Namita; Currier, Dianne; Tin, Adrienne; Merville, Jessica; Galfalvy, Hanga C.; Sher, Leo; Grunebaum, Michael F.; Burke, Ainsley K.; Mann, J. John

2013-01-01

Because Bipolar Disorder (BD) individuals making highly lethal suicide attempts have greater injury burden and risk for suicide, early identification is critical. BD patients were classified as high- or low-lethality attempters. High-lethality attempts required inpatient medical treatment. Mixed effects logistic regression models and permutation analyses examined correlations between lethality, number, and order of attempts. High-lethality attempters reported greater suicidal intent and more previous attempts. Multiple attempters showed no pattern of incremental lethality increase with subsequent attempts, but individuals with early high-lethality attempts more often made high-lethality attempts later. A subset of high-lethality attempters make only high-lethality attempts. However, presence of previous low-lethality attempts does not indicate that risk for more lethal, possibly successful, attempts is reduced. PMID:19590998

Organophosphorus insecticides in honey, pollen and bees (Apis mellifera L.) and their potential hazard to bee colonies in Egypt.

PubMed

Al Naggar, Yahya; Codling, Garry; Vogt, Anja; Naiem, Elsaied; Mona, Mohamed; Seif, Amal; Giesy, John P

2015-04-01

There is no clear single factor to date that explains colony loss in bees, but one factor proposed is the wide-spread application of agrochemicals. Concentrations of 14 organophosphorous insecticides (OPs) in honey bees (Apis mellifera) and hive matrices (honey and pollen) were measured to assess their hazard to honey bees. Samples were collected during spring and summer of 2013, from 5 provinces in the middle delta of Egypt. LC/MS-MS was used to identify and quantify individual OPs by use of a modified Quick Easy Cheap Effective Rugged Safe (QuEChERS) method. Pesticides were detected more frequently in samples collected during summer. Pollen contained the greatest concentrations of OPs. Profenofos, chlorpyrifos, malation and diazinon were the most frequently detected OPs. In contrast, ethoprop, phorate, coumaphos and chlorpyrifos-oxon were not detected. A toxic units approach, with lethality as the endpoint was used in an additive model to assess the cumulative potential for adverse effects posed by OPs. Hazard quotients (HQs) in honey and pollen ranged from 0.01-0.05 during spring and from 0.02-0.08 during summer, respectively. HQs based on lethality due to direct exposure of adult worker bees to OPs during spring and summer ranged from 0.04 to 0.1 for best and worst case respectively. It is concluded that direct exposure and/or dietary exposure to OPs in honey and pollen pose little threat due to lethality of bees in Egypt. Copyright © 2014 Elsevier Inc. All rights reserved.

Standardized laboratory tests with 21 species of temperate and tropical sepsid flies confirm their suitability as bioassays of pharmaceutical residues (ivermectin) in cattle dung.

PubMed

Blanckenhorn, Wolf U; Puniamoorthy, Nalini; Schäfer, Martin A; Scheffczyk, Adam; Römbke, Jörg

2013-03-01

Veterinary pharmaceuticals excreted in the dung of treated livestock can have strong non-target effects on the dung organism community. We report results of ecotoxicological tests with ivermectin for 21 species of temperate (Europe, North America) and tropical (Asia, Central America) black scavenger flies (Diptera: Sepsidae), using standardized methods developed previously for the yellow dung fly and the face fly. Our study documents great variation in ivermectin sensitivity of more than two orders of magnitude among species and even populations within species: estimated lethal effect concentrations LC(50) (at which 50% of the flies died) ranged from 0.05 to 18.55 μg/kg dung fresh weight (equivalent to 0.33-132.22 μg/kg dung dry weight). We also show that controlled laboratory tests can--within reasonable limits-be extended to the field or to laboratory settings without climate control, as obtained LC(50) were roughly similar. In addition to lethal effects, our study revealed relevant sub-lethal effects at lower ivermectin concentrations in terms of prolonged development, smaller body size and reduced juvenile growth rate. Finally, oviposition choice experiments showed that females generally do not discriminate against dung containing ivermectin residues. We conclude that sepsid flies are well suited test organisms for pharmaceutical residues in the dung of livestock due to their ease and speed of rearing and handling, particularly in the tropics, where high-tech laboratory equipment is often not available. Copyright © 2012 Elsevier Inc. All rights reserved.

Effect of coniine on the developing chick embryo.

PubMed

Forsyth, C S; Frank, A A; Watrous, B J; Bohn, A A

1994-04-01

Coniine, an alkaloid from Conium maculatum (poison hemlock), has been shown to be teratogenic in livestock. The major teratogenic outcome is arthrogryposis, presumably due to nicotinic receptor blockade. However, coniine has failed to produce arthrogryposis in rats or mice and is only weakly teratogenic in rabbits. The purpose of this study was to evaluate and compare the effects of coniine and nicotine in the developing chick. Concentrations of coniine and nicotine sulfate were 0.015%, 0.03%, 0.075%, 0.15%, 0.75%, 1.5%, 3%, and 6% and 1%, 5%, and 10%, respectively. Both compounds caused deformations and lethality in a dose-dependent manner. All concentrations of nicotine sulfate caused some lethality but a no effect level for coniine lethality was 0.75%. The deformations caused by both coniine and nicotine sulfate were excessive flexion or extension of one or more toes. No histopathological alterations or differences in bone formation were seen in the limbs or toes of any chicks from any group; however, extensive cranial hemorrhage occurred in all nicotine sulfate-treated chicks. There was a statistically significant (P < or = 0.01) decrease in movement in coniine and nicotine sulfate treated chicks as determined by ultrasound. Control chicks were in motion an average of 33.67% of the time, while coniine-treated chicks were only moving 8.95% of a 5-min interval, and no movement was observed for nicotine sulfate treated chicks. In summary, the chick embryo provides a reliable and simple experimental animal model of coniine-induced arthrogryposis. Data from this model support a mechanism involving nicotinic receptor blockade with subsequent decreased fetal movement.

Effects of sub-lethal doses of glyphosate on honeybee navigation.

PubMed

Sol Balbuena, María; Tison, Léa; Hahn, Marie-Luise; Greggers, Uwe; Menzel, Randolf; Farina, Walter M

2015-07-10

Glyphosate (GLY) is a herbicide that is widely used in agriculture for weed control. Although reports about the impact of GLY in snails, crustaceans and amphibians exist, few studies have investigated its sub-lethal effects in non-target organisms such as the honeybee Apis mellifera, the main pollen vector in commercial crops. Here, we tested whether exposure to three sub-lethal concentrations of GLY (2.5, 5 and 10 mg/L corresponding to 0.125, 0.250 and 0.500 µg/animal) affects the homeward flight path of honeybees in an open field. We performed an experiment in which forager honeybees were trained to an artificial feeder, and then captured, fed with sugar solution containing GLY traces and released from a novel site (the release site, RS) either once or twice. Their homeward trajectories were tracked using harmonic radar technology. We found that honeybees that had been fed with solution containing 10 mg/L GLY spent more time performing homeward flights than control bees or bees treated with lower GLY concentrations. They also performed more indirect homing flights. Moreover, the proportion of direct homeward flights performed after a second release at the RS increased in control bees but not in treated bees. These results suggest that, in honeybees, exposure to GLY doses commonly found in agricultural settings impairs the cognitive capacities needed to retrieve and integrate spatial information for a successful return to the hive. Therefore, honeybee navigation is affected by ingesting traces of the most widely used herbicide worldwide, with potential long-term negative consequences for colony foraging success. © 2015. Published by The Company of Biologists Ltd.

Effects of short- and long-term exposures to copper on lethal and reproductive endpoints of the harpacticoid copepod Tigriopus fulvus.

PubMed

Biandolino, Francesca; Parlapiano, Isabella; Faraponova, Olga; Prato, Ermelinda

2018-01-01

The long-term exposure provides a realistic measurement of the effects of toxicants on aquatic organisms. The harpacticoid copepod Tigriopus fulvus has a wide geographical distribution and is considered as an ideal model organism for ecotoxicological studies for its good sensitivity to different toxicants. In this study, acute, sub-chronic and chronic toxicity tests based on lethal and reproductive responses of Tigriopus fulvus to copper were performed. The number of moults during larval development was chosen as an endpoint for sub-chronic test. Sex ratio, inhibitory effect on larval development, hatching time, fecundity, brood number, nauplii/brood, total newborn production, etc, were calculated in the chronic test (28d). Lethal effect of copper to nauplii showed the LC50-48h of 310 ± 72µgCu/L (mean ± sd). It was observed a significant inhibition of larval development at sublethal copper concentrations, after 4 and 7 d. After 4d, the EC50 value obtained for the endpoint in "moult naupliar reduction" was of 55.8 ± 2.5µgCu/L (mean ± sd). The EC50 for the inhibition of naupliar development into copepodite stage, was of 21.7 ± 4.4µgCu/L (mean ± sd), after 7 days. Among the different traits tested, copper did not affect sex ratio and growth, while fecundity and total nauplii production were the most sensitive endpoints. The reproductive endpoints offer the advantage of being detectable at very low pollutant concentrations. Copyright © 2017 Elsevier Inc. All rights reserved.

Insecticidal and repellent activity of Hiptage benghalensis L. Kruz (Malpighiaceae) against mosquito vectors.

PubMed

Lalrotluanga; Ngente, Lalchawimawii; Nachimuthu, Senthil Kumar; Guruswami, Gurusubramanian

2012-09-01

Plant-based insecticides for vector control are urgently needed for Anopheles barbirostris, Culex quinquefasciatus, and Aedes albopictus which are the primary vectors of malaria, lymphatic filariasis, and dengue, respectively, in India and other South East Asian countries. In the present study, larvicidal, adulticidal, and repellent activities of acetone root bark extract of Hiptage benghalensis were tested against the larvae and adults of the three mosquito vectors. The acetone root bark extracts of H. benghalensis was more effective as larvicides with low LC(50) (11.15-16.78 ppm) and LT50 (1.25-4.84 h at 200 and 400 ppm) values. Results of log probit analysis (at 95 % confidence level) and regression analysis of crude acetone root bark extract of H. benghalensis revealed that lethal concentration (LC(50)) values gradually decreased with the exposure periods; lethal time (LT(50)) decreased with the concentration, and the mortality is positively correlated with the concentration. The order of susceptibility of the three mosquito species was as follows: A. albopictus > A. barbirostris > C. quinquefascitus. Biochemical changes were also evidenced in third instar larvae of three mosquito species following a sublethal exposure for 24 h. The level of sugar, glycogen, lipids, and proteins was significantly (P < 0.05) reduced in larvae treated with H. benghalensis. The acetone root bark extracts of H. benghalensis is less toxic to adults and repelled laboratory-reared female A. barbirostris, A. albopictus, and C. quinquefascitus with the short median protection times of 57.66-135, 72.41-134.16, and 47.66-93 min, respectively. The present investigation proves it as a potent larvicide against A. albopictus, A. barbirostris, and C. quinquefascitus, which can be recommended to control these mosquito species on its breeding site. However, further investigations are needed to confirm the lethal effects of H. benghalensis in field conditions and its impact on the nontarget organisms.

Monochloroacetic acid lethality in the rat in relation to lactic acid accumulation in the cerebrospinal fluid

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

Mitroka, J.G.

1989-01-01

Potential antidotes for human exposure to monochloroacetic acid (MCA) were evaluated using a rodent model. Dichloroacetic acid (DCA) and phenobarbital (PB) but not ethanol or phenytoin, were found to be effective antidotes to monochloroacetic acid (MCA) in rats. DCA (110 mg/kg, ip), administered to rats 15 minutes after a LD-80 of MCA (80 mg/kg, iv), consistently reduced mortality to 0%, while PB reduced mortality to less than 20%. Both DCA and PB were found to be similarly effective in mice. The hypothesis that PB reduces mortality in MCA treated rats by altering the metabolic disposition of MCA was evaluated andmore » rejected. Administration of PB to rats treated with a lethal dose of ({sup 14}C)MCA did not alter the concentrations of MCA or its metabolites in plasma or cerebrospinal fluid (CSF), or the extent of covalent binding between radioactivity equivalent to ({sup 14}C)MCA and brain proteins. The relationship between altered blood-brain barrier permeability and death in MCA treated rats was investigated. Treatment with MCA (80 mg/kg, iv) was associated with a significant (50%) increase in the permeability of the rat blood-brain barrier to ({sup 125}I)BSA. The effect was not altered by treatment with PB, however, suggesting that altered blood-brain barrier permeability does not have an important role in the lethal effect of MCA in rats. The effect of MCA on brain carbohydrate metabolism in vivo was investigated. CSF and blood lactic acid concentrations increased in MCA treated rats, and the increase in CSF levels was dose related. In individual MCA treated rats, CSF lactate concentrations paralleled the time course of ataxia and a discrete threshold for death (18 mmol/L) was observed. The relationship between excess brain lactate levels and death in MCA treated rats was investigated further.« less

In situ effects of pesticides on amphibians in the Sierra Nevada

USGS Publications Warehouse

Sparling, Donald W.; Bickham, John W.; Cowman, Deborah; Fellers, Gary M.; Lacher, Thomas E.; Matson, Cole W.; McConnell, Laura

2015-01-01

For more than 20 years, conservationists have agreed that amphibian populations around the world are declining. Results obtained through laboratory or mesocosm studies and measurement of contaminant concentrations in areas experiencing declines have supported a role of contaminants in these declines. The current study examines the effects of contaminant exposure to amphibians in situ in areas actually experiencing declines. Early larval Pseudacris regilla were translocated among Lassen Volcanic, Yosemite and Sequoia National Parks, California, USA and caged in wetlands in 2001 and 2002 until metamorphosis. Twenty contaminants were identified in tadpoles with an average of 1.3–5.9 (maximum = 10) contaminants per animal. Sequoia National Park, which had the greatest variety and concentrations of contaminants in 2001, also had tadpoles that experienced the greatest mortality, slowest developmental rates and lowest cholinesterase activities. Yosemite and Sequoia tadpoles and metamorphs had greater genotoxicity than those in Lassen during 2001, as determined by flow cytometry. In 2001 tadpoles at Yosemite had a significantly higher rate of malformations, characterized as hemimelia (shortened femurs), than those at the other two parks but no significant differences were observed in 2002. Fewer differences in contaminant types and concentrations existed among parks during 2002 compared to 2001. In 2002 Sequoia tadpoles had higher mortality and slower developmental rates but there was no difference among parks in cholinesterase activities. Although concentrations of most contaminants were below known lethal concentrations, simultaneous exposure to multiple chemicals and other stressors may have resulted in lethal and sublethal effects.

Susceptibility of Haemophilus influenzae to chloramphenicol and eight beta-lactam antibiotics.

PubMed Central

Thirumoorthi, M C; Kobos, D M; Dajani, A S

1981-01-01

We examined the minimal inhibitory concentrations and minimal bactericidal concentrations of chloramphenicol, ampicillin, ticarcillin, cefamandole, cefazolin, cefoxitin, cefotaxime, ceforanide, and moxalactam for 100 isolates of Haemophilus influenzae, 25 of which produced beta-lactamase. Susceptibility was not influenced by the capsular characteristic of the organism. The mean minimal inhibitory concentrations of cefamandole, ticarcillin, and ampicillin for beta-lactamase-producing strains were 3-, 120-, and 400-fold higher than their respective mean minimal inhibitory concentrations for beta-lactamase-negative strains. No such difference was noted for the other antibiotics. We performed time-kill curve studies, using chloramphenicol, ampicillin, cefamandole, cefotaxime, and moxalactam with two concentrations of the antimicrobial agents (4 or 20 times the minimal inhibitory concentrations) and two inoculum sizes (10(4) or 10(6) colony-forming units per ml). The inoculum size had no appreciable effect on the rate of killing of beta-lactamase-negative strains. The rates at which beta-lactamase-producing strains were killed by chloramphenicol, cefotaxime, and moxalactam was not influenced by the inoculum size. Whereas cefamandole in high concentrations was able to kill at 10(6) colony-forming units/ml of inoculum, it had only a temporary inhibiting effect at low drug concentrations. Methicillin and the beta-lactamase inhibitor CP-45,899 were able to neutralize the inactivation of cefamandole by a large inoculum of beta-lactamase-producing H. influenzae. PMID:6974541

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

Fatal intoxications associated with the designer opioid AH-7921.

PubMed

Kronstrand, R; Thelander, G; Lindstedt, D; Roman, M; Kugelberg, F C

2014-10-01

AH-7921 (3,4-dichloro-N-[(1-dimethylamino)cyclohexylmethyl]benzamide) is a designer opioid with ∼80% of morphine's µ-agonist activity. Over a 6-month period, we encountered nine deaths where AH-7921 was involved and detected in blood from the deceased. Shortly after the last death, on August 1 2013, AH-7921 was scheduled as a narcotic and largely disappeared from the illicit market in Sweden. AH-7921 was measured by a selective liquid chromatography-MS-MS method and the concentrations of AH-7921 ranged from 0.03 to 0.99 µg/g blood. Six of our cases had other drugs of abuse on board and most had other medications such as benzodiazepines, antidepressants and analgesics. However, the other medicinal drugs encountered were present in postmortem therapeutic concentrations and unlikely to have contributed to death. In addition to the parent compound, we identified six possible metabolites where two N-demethylated dominated and four mono-hydroxylated were found in trace amounts in the blood. In conclusion, deaths with AH-7921 seem to occur both at low and high concentrations, probably a result of different tolerance to the drug. Hence, it is reasonable to assume that no sharp dividing line exists between lethal and non-lethal concentrations. Further, poly-drug use did not seem to be a major contributing factor for the fatal outcome. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Biological properties of carotenoids extracted from Halobacterium halobium isolated from a Tunisian solar saltern

PubMed Central

2013-01-01

Background Bioactive molecules have received increasing attention due to their nutraceutical attributes and anticancer, antioxidant, antiproliferative and apoptosis-inducing properties. This study aimed to investigate the biological properties of carotenoids extracted from Archaea. Methods Halophilic Archaea strains were isolated from the brine of a local crystallizer pond (TS7) of a solar saltern at Sfax, Tunisia. The most carotenoid-producing strain (M8) was investigated on heptoma cell line (HepG2), and its viability was assessed by the MTT-test. The cells were incubated with different sub-lethal extract rates, with carotenoid concentrations ranging from 0.2 to 1.5 μM. Antioxidant activity was evaluated through exposing the cells to sub-lethal extract concentrations for 24 hours and then to oxidative stress induced by 60 μM arachidonic acid and 50 μM H2O2. Results Compared to non-treated cells, bacterial carotenoid extracts inhibited HepG2 cell viability (50%). A time and dose effect was observed, with cell viability undergoing a significant (P < 0.05) decrease with extract concentration. After exposure to oxidative stress, control cells underwent a significant (P < 0.05) decrease in viability as compared to the non-treated cells. Conclusions The bacterial extracts under investigation were noted to exhibit the strongest free radical scavenging activity with high carotenoid concentrations. The carotenoid extract also showed significant antiproliferative activity against HepG2 human cancer cell lines. PMID:24090008

Oxidized starch solutions for environmentally friendly aircraft deicers.

PubMed

Plahuta, Joseph M; Teel, Amy L; Ahmad, Mushtaque; Beutel, Mark W; Rentz, Jeremy A; Watts, Richard J

2011-09-01

Deicers currently used for aircraft deicing, including ethylene glycol and propylene glycol, pose significant threats to surface waters, as a result of high biochemical oxygen demand (BOD) and toxicity to aquatic organisms. Oxidized starch may provide a less toxic deicer with lower BOD. The freezing point depression of starch formulations oxidized using hydrogen peroxide and catalysts (i.e., catalyzed hydrogen peroxide [H2O2] propagations-CHP) was 28 degrees C, and viscosities similar to those of commercial deicers were achieved after post-treatment with granular activated carbon. The most effective oxidized starch formulation exerted a 5-day BOD up to 6 times lower than glycol deicers (103 versus 400 to 800 g O2/L). Toxicity to Ceriodaphnia dubia for this formulation (48-hour lethal concentration, 50% [LC50] of 2.73 g/L) was greater than pure propylene glycol (13.1 g/ L), but lower than propylene glycol deicer formulations (1.02 g/L). Organic acids were identified by gas chromatography/mass spectrometry as the primary constituents in the oxidized starch solution. The proposed deicing system would provide effective deicing while exerting minimal environmental effects (e.g., lower toxicity to aquatic organisms and lower BOD). Furthermore, these deicers could be made from waste starch, promoting sustainability.

The effect of iron on metronidazole activity against Trichomonas vaginalis in vitro.

PubMed

Elwakil, Hala Salah; Tawfik, Rania Ayman; Alam-Eldin, Yosra Hussein; Nassar, Doaa Ashraf

2017-11-01

Metronidazole is administered in an inactive form then activated to its cytotoxic form within the hydrogenosome of trichomonads. Two hydrogenosomal proteins, pyruvate ferredoxin oxidoreductase (PFOR) and ferredoxin, play a critical role in the reductive activation of metronidazole. The expression of these proteins and other hydrogenosomal proteins are likewise positively regulated by iron. In the present study, the effect of iron on minimal lethal concentration (MLC) of metronidazole on in vitro cultured Trichomonas vaginalis(T. vaginalis) isolates was investigated. Interestingly, Addition of Ferrous ammonium sulphate (FAS) to T. vaginalis culture led to decrease in the MLC of metronidazole. On using aerobic assay, MLC of metronidazole on untreated T. vaginalis of both isolates was 12.5 μg/ml that decreased to 0.38 μg/ml on FAS treated trichomonads. Also anaerobic assay revealed that MLC on untreated parasites was 3.12 μg/ml that decreased to 0.097 μg/ml and 0.19 μg/ml for isolate 1 and isolate 2 respectively after iron addition. It was concluded that, addition of iron to in vitro cultured T. vaginalis decreases metronidazole MLC that was detected by both aerobic and anaerobic assays. Copyright © 2017 Elsevier Inc. All rights reserved.

Laurel leaf extracts for honeybee pest and disease management: antimicrobial, microsporicidal, and acaricidal activity.

PubMed

Damiani, Natalia; Fernández, Natalia J; Porrini, Martín P; Gende, Liesel B; Álvarez, Estefanía; Buffa, Franco; Brasesco, Constanza; Maggi, Matías D; Marcangeli, Jorge A; Eguaras, Martín J

2014-02-01

A diverse set of parasites and pathogens affects productivity and survival of Apis mellifera honeybees. In beekeeping, traditional control by antibiotics and molecules of synthesis has caused problems with contamination and resistant pathogens. In this research, different Laurus nobilis extracts are tested against the main honeybee pests through an integrated point of view. In vivo effects on bee survival are also evaluated. The ethanol extract showed minimal inhibitory concentration (MIC) values of 208 to 416 μg/mL, having the best antimicrobial effect on Paenibacillus larvae among all substances tested. Similarly, this leaf extract showed a significant antiparasitic activity on Varroa destructor, killing 50 % of mites 24 h after a 30-s exposure, and on Nosema ceranae, inhibiting the spore development in the midgut of adult bees ingesting 1 × 10(4) μg/mL of extract solution. Both ethanol extract and volatile extracts (essential oil, hydrolate, and its main component) did not cause lethal effects on adult honeybees. Thus, the absence of topical and oral toxicity of the ethanol extract on bees and the strong antimicrobial, microsporicidal, and miticidal effects registered in this study place this laurel extract as a promising integrated treatment of bee diseases and stimulates the search for other bioactive phytochemicals from plants.

Toxicity of plant essential oils to different life stages of the poultry red mite, Dermanyssus gallinae, and non-target invertebrates.

PubMed

George, D R; Sparagano, O A E; Port, G; Okello, E; Shiel, R S; Guy, J H

2010-03-01

Seven essential oils with potential as acaricides for use against the poultry red mite, Dermanyssus gallinae (De Geer) (Acari: Dermanyssidae), were selected for study. These products (essential oils of manuka, cade, pennyroyal, thyme, garlic, clove bud and cinnamon bark) were deployed against different life stages of D. gallinae in laboratory tests at the (lethal concentration) LC(50) level for adult mites. For all essential oils tested, toxicity to D. gallinae juveniles was as high as toxicity to adults, if not higher. However, at the LC(50) level determined for adults, some oils were ineffective in preventing hatching of D. gallinae eggs. The essential oils were also tested under laboratory conditions at their LC(90) levels for D. gallinae adults on two model non-target species, the brine shrimp, Artemia salina (L.), and the mealworm beetle, Tenebrio molitor (L.). Results showed that not all essential oils were as toxic to A. salina and T. molitor as they were to D. gallinae, suggesting that it may be possible to select certain oils for development as acaricides against D. gallinae that would have minimal impact on non-target organisms. However, the level of toxicity to A. salina and T. molitor was not consistent across the selected essential oils.

Safety of methionine, a novel biopesticide, to adult and larval honey bees (Apis mellifera L.).

PubMed

Weeks, Emma N I; Schmehl, Daniel R; Baniszewski, Julie; Tomé, Hudson V V; Cuda, James P; Ellis, James D; Stevens, Bruce R

2018-03-01

Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Hereditary hemochromatosis.

PubMed

Walker, E M; Wolfe, M D; Norton, M L; Walker, S M; Jones, M M

1998-01-01

Genetic (hereditary) hemochromatosis is probably the most common autosomal recessive disorder found in white Americans, of whom about 5/1,000 (0.5 percent) are homozygous for the associated gene. The hemochromatosis gene is probably located close to the HLA-A locus on the short arm of chromosome 6. Homozygous individuals may develop severe and potentially lethal hemochromatosis, especially after age 39. Hereditary hemochromatosis involves an increased rate of iron absorption from the gut with subsequent progressive storage of iron in soft organs of the body. Excess iron storage eventually produces pituitary, pancreatic, cardiac, and liver dysfunction and death may result from cardiac arrhythmias, congestive heart failure, and/or hepatic failure or cancer. Early diagnosis can prevent these excess iron-induced problems. Iron overload owing to HLA-linked hereditary hemochromatosis can be distinguished from other causes of hemochromatosis by liver biopsies and interpretations. Patients at risk for genetic hemochromatosis should be screened, identified, and treated as early as age 20 to prevent or minimize the deadly complications of hemochromatosis. Population screening should include measurements of serum iron concentration, total iron binding capacity (TIBC), percent saturation of transferrin, and serum ferritin concentrations. Family members of hereditary hemochromatosis patients are at increased risk and should be tested. Screening, identification and early treatment (phlebotomies, sometimes in combination with the use of Desferal or other iron-chelating agents) may help prevent or reduce iron-related organ damage and premature deaths. Early diagnosis and treatment will reduce the population of aging individuals with severe, complicated hemochromatosis and dramatically reduce medical costs (billions of U.S. dollars per annum) associated with the management of this disease.

Leukemia inhibitory factor protects against experimental lethal Escherichia coli septic shock in mice.

PubMed Central

Waring, P M; Waring, L J; Billington, T; Metcalf, D

1995-01-01

Leukemia inhibitory factor (LIF) has recently been associated with septic shock in humans. In this study we sought to determine, in mice, the role of LIF in septic shock. During sublethal endotoxemia, serum LIF levels, as determined by radio-receptor competition assay, peaked at 2 h and were low (3 ng/ml), whereas in lethal Escherichia coli septic shock serum LIF levels rose progressively (> 30 ng/ml) in the premorbid phase coincident with the development of tissue injury. Single i.v. injections of high doses (up to 50 micrograms per mouse) of recombinant murine LIF had no obvious acute detrimental effects, whereas continued i.p. administration (30 micrograms per mouse per day) for 3-4 days induced a fatal catabolic state without evidence of preceding hemodynamic collapse or shock. Simultaneous or subsequent administration of high doses of LIF had no effect on mortality from sublethal and lethal E. coli septic shock, whereas prior administration conferred significant protection against lethality (P << 0.001 by log-rank test), an effect that was dose and interval dependent. This protective effect resembled endotoxin tolerance and was characterized by suppression of E. coli-induced serum tumor necrosis factor concentration (P < 0.05), reduction in the number of viable bacteria (P < 0.05), and prevention of sepsis-induced tissue injury. These observations suggest that systemic LIF production is part of the host response to both endotoxin and sepsis-induced tissue injury. Images Fig. 2 Fig. 5 PMID:7877978

Lethal factor antibodies contribute to lethal toxin neutralization in recipients of anthrax vaccine precipitated.

PubMed

Dumas, Eric K; Garman, Lori; Cuthbertson, Hannah; Charlton, Sue; Hallis, Bassam; Engler, Renata J M; Choudhari, Shyamal; Picking, William D; James, Judith A; Farris, A Darise

2017-06-08

A major difference between two currently licensed anthrax vaccines is presence (United Kingdom Anthrax Vaccine Precipitated, AVP) or absence (United States Anthrax Vaccine Adsorbed, AVA) of quantifiable amounts of the Lethal Toxin (LT) component Lethal Factor (LF). The primary immunogen in both vaccine formulations is Protective Antigen (PA), and LT-neutralizing antibodies directed to PA are an accepted correlate of vaccine efficacy; however, vaccination studies in animal models have demonstrated that LF antibodies can be protective. In this report we compared humoral immune responses in cohorts of AVP (n=39) and AVA recipients (n=78) matched 1:2 for number of vaccinations and time post-vaccination, and evaluated whether the LF response contributes to LT neutralization in human recipients of AVP. PA response rates (≥95%) and PA IgG concentrations were similar in both groups; however, AVP recipients exhibited higher LT neutralization ED 50 values (AVP: 1464.0±214.7, AVA: 544.9±83.2, p<0.0001) and had higher rates of LF IgG positivity (95%) compared to matched AVA vaccinees (1%). Multiple regression analysis revealed that LF IgG makes an independent and additive contribution to the LT neutralization response in the AVP group. Affinity purified LF antibodies from two independent AVP recipients neutralized LT and bound to LF Domain 1, confirming contribution of LF antibodies to LT neutralization. This study documents the benefit of including an LF component to PA-based anthrax vaccines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Decreased Expression of Stable RNA Can Alleviate the Lethality Associated with RNase E Deficiency in Escherichia coli.

PubMed

Himabindu, P; Anupama, K

2017-04-15

The endoribonuclease RNase E participates in mRNA degradation, rRNA processing, and tRNA maturation in Escherichia coli , but the precise reasons for its essentiality are unclear and much debated. The enzyme is most active on RNA substrates with a 5'-terminal monophosphate, which is sensed by a domain in the enzyme that includes residue R169; E. coli also possesses a 5'-pyrophosphohydrolase, RppH, that catalyzes conversion of 5'-terminal triphosphate to 5'-terminal monophosphate on RNAs. Although the C-terminal half (CTH), beyond residue approximately 500, of RNase E is dispensable for viability, deletion of the CTH is lethal when combined with an R169Q mutation or with deletion of rppH In this work, we show that both these lethalities can be rescued in derivatives in which four or five of the seven rrn operons in the genome have been deleted. We hypothesize that the reduced stable RNA levels under these conditions minimize the need of RNase E to process them, thereby allowing for its diversion for mRNA degradation. In support of this hypothesis, we have found that other conditions that are known to reduce stable RNA levels also suppress one or both lethalities: (i) alterations in relA and spoT , which are expected to lead to increased basal ppGpp levels; (ii) stringent rpoB mutations, which mimic high intracellular ppGpp levels; and (iii) overexpression of DksA. Lethality suppression by these perturbations was RNase R dependent. Our work therefore suggests that its actions on the various substrates (mRNA, rRNA, and tRNA) jointly contribute to the essentiality of RNase E in E. coli IMPORTANCE The endoribonuclease RNase E is essential for viability in many Gram-negative bacteria, including Escherichia coli Different explanations have been offered for its essentiality, including its roles in global mRNA degradation or in the processing of several tRNA and rRNA species. Our work suggests that, rather than its role in the processing of any one particular substrate, its distributed functions on all the different substrates (mRNA, rRNA, and tRNA) are responsible for the essentiality of RNase E in E. coli . Copyright © 2017 American Society for Microbiology.

40 CFR 721.5960 - N,N′-Bis(2-(2-(3-alkyl)thia- zoline) vinyl)-1,4-pheny-lene-dia-mine methyl sulfate double salt...

Code of Federal Regulations, 2010 CFR

2010-07-01

...), (f) (concentration set at 1 percent), (g)(1)(iii), (g)(1), (may be lethal if inhaled or in contact with eyes), (g)(2)(i), (g)(2)(ii), (g)(2)(iv), (g)(2)(v), and (g)(5). The provision of § 721.72(d...

40 CFR 721.5960 - N,N′-Bis(2-(2-(3-alkyl)thia- zoline) vinyl)-1,4-pheny-lene-dia-mine methyl sulfate double salt...

Code of Federal Regulations, 2011 CFR

2011-07-01

...), (f) (concentration set at 1 percent), (g)(1)(iii), (g)(1), (may be lethal if inhaled or in contact with eyes), (g)(2)(i), (g)(2)(ii), (g)(2)(iv), (g)(2)(v), and (g)(5). The provision of § 721.72(d...

Combined effect of seaweed (Sargassum wightii) and Bacillus thuringiensis var. israelensis on the coastal mosquito,Anopheles sundaicus, in Tamil Nadu, India

USDA-ARS?s Scientific Manuscript database

Studies were made of the extract of Sargassum wightii combined with Bacillus thuringiensis var. israelensis (Bti) for control of the malaria vector Anopheles sundaicus. Treatment of mosquito larvae with 0.001% S. wightii extract indicated median lethal concentrations (LC50) of 88, 73, 134, 156, and...

Sub-Inhibitory Concentrations of the Antibiotic Florfenicol Reduces Invasion in Isolates of Multi-Drug Resistant Salmonella Typhimurium DT104

USDA-ARS?s Scientific Manuscript database

Virulence can be enhanced in certain bacteria that are exposed to sub-lethal levels of antibiotics. Salmonella enterica serovar Typhimurium DT104 is resistant to five different antibiotics, including florfenicol. Using real-time PCR and a tissue culture invasion assay, we investigated the impact of ...

Development of resistance of mutans streptococci and Porphyromonas gingivalis to chlorhexidine digluconate and amine fluoride/stannous fluoride-containing mouthrinses, in vitro.

PubMed

Kulik, Eva M; Waltimo, Tuomas; Weiger, Roland; Schweizer, Irene; Lenkeit, Krystyna; Filipuzzi-Jenny, Elisabeth; Walter, Clemens

2015-07-01

The aim if this study was to determine the minimal inhibitory concentrations of chlorhexidine digluconate and an amine fluoride/stannous fluoride-containing mouthrinse against Porphyromonas gingivalis and mutans streptococci during an experimental long-term subinhibitory exposition. Five P. gingivalis strains and four mutans streptococci were subcultivated for 20-30 passages in subinhibitory concentrations of chlorhexidine digluconate or an amine fluoride/stannous fluoride-containing mouthrinse. Pre-passaging minimal inhibitory concentrations for chlorhexidine ranged from 0.5 to 2 mg/l for mutans streptococci and from 2 to 4 mg/l for the P. gingivalis isolates. For the amine fluoride/stannous fluoride-containing mouthrinse minimal inhibitory values from 0.125 to 0.25% for the mutans streptococci and from 0.063 to 0.125% for the P. gingivalis isolates were determined. Two- to fourfold increased minimal inhibitory concentrations against chlorhexidine were detected for two of the five P. gingivalis isolates, whereas no increase in minimal inhibitory concentrations was found for the mutans streptococci after repeated passaging through subinhibitory concentrations. Repeated exposure to subinhibitory concentrations of the amine fluoride/stannous fluoride-containing mouthrinse did not alter the minimally inhibitory concentrations of the bacterial isolates tested. Chlorhexidine and the amine fluoride/stannous fluoride-containing mouthrinse are effective inhibitory agents against the oral bacterial isolates tested. No general development of resistance against chlorhexidine or the amine fluoride/stannous fluoride-containing mouthrinse was detected. However, some strains showed potential to develop resistance against chlorhexidine after prolonged exposure. The use of chlorhexidine should be limited to short periods of time. The amine fluoride/stannous fluoride-containing mouthrinse appears to have the potential to be used on a long-term basis.

Acute and chronic toxicity of nickel to rainbow trout (Oncorhynchus mykiss).

PubMed

Brix, Kevin V; Keithly, James; DeForest, David K; Laughlin, Jim

2004-09-01

Of the fish species tested in chronic Ni exposures, rainbow trout (Oncorhynchus mykiss) is the most sensitive. To develop additional Ni toxicity data and to investigate the toxic mode of action for Ni, we conducted acute (96-h) and chronic (85-d early life-stage) flow-through studies using rainbow trout. In addition to standard toxicological endpoints, we investigated the effects of Ni on ionoregulatory physiology (Na, Ca, and Mg). The acute median lethal concentration for Ni was 20.8 mg/L, and the 24-h gill median lethal accumulation was 666 nmol/g wet weight. No effects on plasma Ca, Mg, or Na were observed during acute exposure. In the chronic study, no significant effects on embryo survival, swim-up, hatching, or fingerling survival or growth were observed at dissolved Ni concentrations up to 466 microg/L, the highest concentration tested. This concentration is considerably higher than the only other reported chronic no-observed-effect concentration (<33 microg/L) for rainbow trout. Accumulation of Ni in trout eggs indicates the chorion is only a partial barrier with 36%, 63%, and 1% of total accumulated Ni associated with the chorion, yolk, and embryo, respectively. Whole-egg ion concentrations were reduced by Ni exposure. However, most of this reduction occurred in the chorion rather than in the embryos, and no effects on hatching success or larval survival were observed as a result. Plasma ion concentrations measured in swim-up fingerlings at the end of the chronic-exposure period were not significantly reduced by exposure to Ni. Nickel accumulated on the gill in an exponential manner but plateaued in trout plasma at waterborne Ni concentrations of 118 microg/L or greater. Consistent with previous studies, Ni did not appear to disrupt ionoregulation in acute exposures of rainbow trout. Our results also suggest that Ni is not an ionoregulatory toxicant in long-term exposures, but the lack of effects in the highest Ni treatment precludes a definitive conclusion.

Laboratory evaluation of three strains of the entomopathogenic fungus Metarhizium anisopliae for controlling Dermanyssus gallinae.

PubMed

Tavassoli, M; Ownag, A; Pourseyed, S H; Mardani, K

2008-06-01

The pathogenicity of three strains of the entomopathogenic fungus Metarhizium anisopliae on different life stages of Dermanyssus gallinae was evaluated in the laboratory. All the strains tested were virulent to D. gallinae but pathogenicity varied among the strains. Strain V245 induced a higher mortality rate using different concentrations than other two strains. The estimated median lethal concentration of different strains of M. anisopliae against D. gallinae varied depending on the exposure time of D. gallinae to M. anisopliae. It was concluded that the pathogenicity of the entomopathogenic fungus M. anisopliae on different life stages of D. gallinae was concentration and time dependent.

Effect of delayed anthrax vaccine dose on Bacillus anthracis protective antigen IgG response and lethal toxin neutralization activity.

PubMed

Pittman, Phillip R; Fisher, Diana; Quinn, Xiaofei; Schmader, Trevor; Barrera-Oro, Julio G

2013-10-17

We describe the Bacillus anthracis protective antigen IgG antibody response and the B. anthracis lethal toxin neutralization activity to a delayed dose of anthrax vaccine adsorbed (AVA, BioThrax(®)) using validated assays. 373 individuals received 1, 2, or 3 priming doses, 18-24 months afterward, they received a delayed dose of AVA. Overall, 23.6% of subjects showed detectable anti-PA IgG before the boost, compared to 99.2% (P<0.0001) 28 days after the boost. Geometric mean anti-PA IgG concentration (GMC) was 1.66 μg/mL before and 887.82 μg/mL after the boost (P<0.0001). The proportion of individuals with four-fold increase in GMC following the boost ranged from 93.8% to 100%. Robust anti-PA IgG levels and B. anthracis lethal toxin neutralization activity are induced when an AVA dose is delayed as long as two years. These data support continuing with the vaccination schedule when a dose is delayed as long as two years rather than restarting the series. Published by Elsevier Ltd.

Developmental toxicity and risk assessment of nonylphenol to the South American toad, Rhinella arenarum.

PubMed

Mariel, Aronzon Carolina; Alejandra, Babay Paola; Silvia, Pérez Coll Cristina

2014-09-01

The toxicity of Nonylphenol, an emerging pollutant, on the common South American toad Rhinella arenarum was stage and time dependent, thus Median Lethal Concentrations (LC50) for acute (96h), short-term chronic (168h) and chronic exposure (336h) were 1.06; 0.96 and 0.17mgNP/L from embryonic period (S.4), whereas for exposure from larvae (S.25), LC50 remained constant at 0.37mgNP/L from 96h to 168h, decreasing to 0.11mgNP/L at 336h. NOEC-168h for exposure from embryos was 0.025mgNP/L. The Teratogenic Potential (NOEC-lethality/NOEC-sublethal effects) was 23 times higher than the threshold value, indicating a high risk for embryos to be malformed in absence of significant lethality and representing a threat for the species conservation. By comparing with other amphibians, the early development of R. arenarum was very sensitive to NP. The results highlight the relevance of extending the exposure time and look for the most sensitive stage in order to perform the bioassays for conservation purposes. Copyright © 2014 Elsevier B.V. All rights reserved.

Whole body protection against lethal ionizing radiation in mice by REC-2001: a semi-purified fraction of Podophyllum hexandrum.

PubMed

Lata, M; Prasad, J; Singh, S; Kumar, R; Singh, L; Chaudhary, P; Arora, R; Chawla, R; Tyagi, S; Soni, N L; Sagar, R K; Devi, M; Sharma, R K; Puri, S C; Tripathi, R P

2009-01-01

The current study has concentrated on assessment of the radioprotective potential of REC-2001, a semi-purified fraction of rhizomes of Podophyllum hexandrum, in Swiss albino Strain 'A' mice exposed to 10 Gy whole-body gamma radiation. Animals were treated with 10 and 15 mg/kg b wt (i.p.) of REC-2001 1h prior to exposure to a lethal dose of gamma-radiation (10 Gy) and observed upto 30 days. For analysis of maximum tolerable dose (MTD), LD(50) and acute toxic dose, different concentrations of the extract were administered to animals and their mortality and morbidity status was observed upto 72 h and one week, respectively. Dose reduction factor (DRF) was determined by exposing REC-2001 pre-treated mice to supra-lethal doses of gamma-radiation. Endogenous spleen colony forming units (CFU), DNA strand breaks in thymocytes (alkaline halo assay) and lipid degradation was studied to understand the mechanism of radioprotection. A single dose of REC-2001 (10 and 15 mg/kg b wt i.p.) exhibited >90% survival in the pre-treated irradiated group versus no survival in radiation control group. Single doses of upto 75 mg/kg b wt (i.p.) did not cause any mortality (MTD) in mice. REC-2001, a dose of 90 mg/kg b wt, resulted in 50% mortality (LD(50)), while the LD(100) was 115 mg/kg b wt REC-2001 exhibited a DRF of 1.62. CFU counts in the REC-2001 treated group were found significantly high (5.33/spleen) as compared to controls. Exposure of thymocytes to 10 Gy radiation resulted in increased halo diameter (45+/-3 microm) in comparison to untreated controls (8+/-1 microm). REC-2001 administration (500 microg/ml) decreased the halo diameter to 15+/-2 microm. Radiation-induced lipid degradation was also inhibited by REC-2001. The present study has revealed that REC-2001 is a promising radioprotective fraction that can be effectively used against lethal doses of gamma-radiation after further investigations in higher animal models.

Pre-acclimation to low ammonia improves ammonia handling in common carp (Cyprinus carpio) when exposed subsequently to high environmental ammonia.

PubMed

Shrivastava, Jyotsna; Sinha, Amit Kumar; Datta, Surjya Narayan; Blust, Ronny; De Boeck, Gudrun

2016-11-01

We tested whether exposing fish to low ammonia concentrations induced acclimation processes and helped fish to tolerate subsequent (sub)lethal ammonia exposure by activating ammonia excretory pathways. Common carp (Cyprinus carpio) were pre-exposed to 0.27mM ammonia (∼10% 96h LC 50 ) for 3, 7 and 14days. Thereafter, each of these pre-exposed and parallel naïve groups were exposed to 1.35mM high environmental ammonia (HEA, ∼50% 96h LC 50 ) for 12h and 48h to assess the occurrence of ammonia acclimation based on sub-lethal end-points, and to lethal ammonia concentrations (2.7mM, 96h LC 50 ) in order to assess improved survival time. Results show that fish pre-exposed to ammonia for 3 and 7days had a longer survival time than the ammonia naïve fish. However, this effect disappeared after prolonged (14days) pre-exposure. Ammonia excretion rate (J amm ) was strongly inhibited (or even reversed) in the unacclimated groups during HEA. On the contrary, after 3days the pre-exposure fish maintained J amm while after 7days these pre-acclimated fish were able to increase J amm efficiently. Again, this effect disappeared after 14days of pre-acclimation. The efficient ammonia efflux in pre-acclimated fish was associated with the up-regulation of branchial mRNA expression of ammonia transporters and exchangers. Pre-exposure with ammonia for 3-7days stimulated an increment in the transcript level of gill Rhcg-a and Rhcg-b mRNA relative to the naïve control group and the up-regulation of these two Rhcg homologs was reinforced during subsequent HEA exposure. No effect of pre-exposure was noted for Rhbg. Relative to unacclimated fish, the transcript level of Na + /H + exchangers (NHE-3) was raised in 3-7days pre-acclimated fish and remained higher during the subsequent HEA exposure while gill H + -ATPase activities and mRNA levels were not affected by pre-acclimation episodes. Likewise, ammonia pre-acclimated fish with or without HEA exposure displayed pronounced up-regulation in Na + /K + -ATPase activity and mRNA expression relative to the corresponding ammonia naïve groups. Overall, these data suggest that ammonia acclimation was evident for both lethal and the sub-lethal endpoints through priming mechanisms in ammonia excretory transcriptional processes, but these acclimation effects were transient and disappeared after prolonged pre-exposure. Copyright © 2016 Elsevier B.V. All rights reserved.

Telling children their mother is seriously ill or dying: mapping French people's views.

PubMed

Muñoz Sastre, M T; Sorum, P C; Mullet, E

2016-01-01

What to tell children when their mother's life is seriously endangered is a largely unstudied issue. We had 255 lay persons in France judge the appropriateness of the parents' behaviour in 48 scenarios of parents dealing with this problem. The scenarios comprised according to a four within-subject orthogonal design: child's age (4, 6, 8 or 10 years), severity of disease (lethal or worrisome but curable), child's concern or not about his or her mother's illness and parents' decision about how much to tell (tell nothing, minimize or tell the full truth). Cluster analysis revealed four clusters, labelled 'always tell the truth' (33%), 'tell the truth or minimize' (16%), 'tell nothing or minimize' (22%) and 'depends on child's age and level of concern' (29%). Women and participants who had already faced breaking bad news like this to children were more frequently members of the two 'tell the truth' clusters than other participants. People who have already experienced a situation of having to tell a child about their mother's bad health tend to think, more than others, that telling the truth is the best policy. © 2015 John Wiley & Sons Ltd.

DDE poisoning in an adult bald eagle

USGS Publications Warehouse

Garcelon, D.K.; Thomas, N.J.

1997-01-01

A 12-year-old female bald eagle (Haliaeetus leucocephalus) was found in May 1993 on Santa Catalina Island, California (USA), in a debilitated condition, exhibiting ataxia and tremors; it died within hours. On necropsy, the bird was emaciated but had no evidence of disease or physical injury. Chemical analyses were negative for organophosphorus pesticides and lead poisoning. High concentrations of DDE (wet weight basis) were found in the brain (212 ppm), liver (838 ppm), and serum (53 ppm). Mobilization of DDE, from depleted fat deposits, probably resulted in the lethal concentration in the eagle's brain.

Blood concentrations of clobazam and norclobazam in a lethal case involving clobazam, meprobamate and clorazepate.

PubMed

Pok, Phak-Rop Pos; Mauras, Michel; De Saint Léger, Marie-Noëlle; Kuhlmann, Erika; Charpenel-Durat, Catherine; Navarette, Claudie; Duval, Marie-Laure; De Meo, Pierre

2010-11-01

Clobazam is a benzodiazepine with anti-anxiety and anticonvulsant properties marketed in several countries. Norclobazam, a metabolite of clobazam, has similar pharmacological activity but weaker sedative and tranquilizing effect. The two drugs were detected by GC-MS and determined by HPLC-DAD in the samples from a postmortem case. The femoral blood concentrations of clobazam and norclobazam were 0.72 and 36 μg/mL, respectively. The concentration of the active norclobazam was very high. The sum of both clobazam and norclobazam blood concentration (36.72 μg/mL) was clearly toxic, but was not necessarily fatal. Other associated drugs concentrations were within their therapeutic ranges. Interactions due to drug association were discussed. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Ultrastructural changes in the hepatocytes of juvenile rainbow trout and mature brown trout exposed to copper or zinc

USGS Publications Warehouse

Leland, H.V.

1983-01-01

Morphological changes in hepatocytes of mature brown trout (Salmo trutta Linnaeus) and juvenile rainbow trout (Salmo gairdneri Richardson), accompanying chronic exposures to copper and zinc, were examined by transmission electron microscopy. At a concentration of copper not inhibitory to the final stages of gonadal development or spawning of brown trout, structural alterations included contraction of mitochondria and a tendency for nuclei to be slightly enlarged. Concentrations of copper or zinc lethal to a small fraction (10% and 4%, respectively) of a population of juvenile rainbow trout exposed for 42 d during larval and early juvenile development caused hepatocyte changes in survivors indicative of a reduction in ability to maintain intracellular water and cation balance and possible intranuclear metal sequestering. Specific structural alterations included increased vesiculation of rough endoplasmic reticulum, an increase in the abundance of electron-dense particles in the nucleus, increases in the numbers of multilaminar and globular inclusions, pooling of glycogen, increased autophagocytic activity and an increase in the number of necrotic cells. At advanced stages of toxicosis (concentrations of copper or zinc lethal to approximately 50% of the juveniles exposed for 42 d during development), loss in integrity of mitochondrial membranes, rupturing of plasma and nuclear membranes, separation of granular and fibrillar nuclear components, fragmentation of endoplasmic reticulum, and extensive autophagic vacuolization were significant features of hepatocytes of surviving juvenile rainbow trout. ?? 1983.

Evaluation of antileishmanial, antibacterial and brine shrimp cytotoxic potential of crude methanolic extract of Herb Ocimum basilicum (Lamiacea).

PubMed

Khan, Imran; Ahmad, Kafeel; Khalil, Ali Talha; Khan, Jangrez; Khan, Yusra Ali; Saqib, Muhammad Shahab; Umar, Muhamad Naveed; Ahmad, Hilal

2015-06-01

To collect and screen for ethnopharmacological properties (antileishmanial, antibacterial and brine lethality assays) of medicinal plan Ocimum basilicum from Peshawar region (34.008 latitude and 71.57 altitudes). In the present study a general antileishmanial activity against Leishmania tropica strair was carried out. The antibacterial potential of the plant was performed against 06 gram positiv and 06 gram negative bacteria. Brine shrimp cyto- toxicity assay at different concentrations were investigated. The anti-promastigotes profile of the plant showed good antileishmanial activity exhibited LC50 value 21.67 µg/mL. The result for gram positive antibacterial activity revealed that the O. basilicum leaves extract possesses significant inhibitory activity at highest two concentrations ranging from 20.66 ± 0.31 to 31.86 ± 0.80 for Clostridium perfringens type C and Bacillus subtitilis, respectively, as compared to the gentamycin (27.36 ± 0.55 and 21.80 ± 0.72, respectively). For gram negative bacteria good activity was observed. A highest zone of inhibition was recorded for Pseudomonas aeroginosa (28.83 ± 0.28) at the highest concentration (10 mg/ mL). The LC50 value obtained for brine shrimp lethality assay was 91.56 µg/mL. The herb basil possesses effective cidal activities which make this plant a good candidate for the isolation of antiprotozoal and antibacterial compounds which may lead to the development of novel drug.

Vehicle capture system

NASA Astrophysics Data System (ADS)

Tacke, Kenneth L.

1998-12-01

Primex Aerospace Company, under contract with the U.S. Army Armament Research Development & Engineering Center (ARDEC), has developed a portable vehicle capture system for use at vehicle checkpoints. Currently when a vehicle does not stop at a checkpoint, there are three possible reactions: let the vehicle go unchallenged, pursue the vehicle or stop the vehicle with lethal force. This system provides a non-lethal alternative that will stop and contain the vehicle. The system is completely portable with the heaviest component weighing less than 120 pounds. It can be installed with no external electrical power or permanent anchors required. In its standby mode, the system does not impede normal traffic, but on command erects a barrier in less than 1.5 seconds. System tests have been conducted using 5,100 and 8.400 pound vehicles, traveling at speeds up to 45 mph. The system is designed to minimize vehicle damage and occupant injury, typically resulting in deceleration forces of less than 2.5 gs on the vehicle. According to the drivers involved in tests at 45 mph, the stopping forces feel similar to a panic stop with the vehicle brakes locked. The system is completely reusable and be rapidly reset.

Evolution of retinal laser therapy: minimum intensity photocoagulation (MIP). Can the laser heal the retina without harming it?

PubMed

Dorin, Giorgio

2004-01-01

Laser photocoagulation is a photo-thermal therapy validated by landmark studies and commonly accepted as the standard of care for various retinal diseases. Although its mechanism of action is still not completely understood, it is normally administered with visible endpoints, true intra-retinal burns that cause chorioretinal scars, which, with time, evolve into expanding areas of atrophy. New hypotheses on the mechanism of action of laser photocoagulation suggest that its therapeutic benefits derive from biologic activities that cannot be inducted within the "burned" area of photocoagulation necrosis, but that occur in the adjacent surrounding areas affected by a lower, sub-lethal, photo-thermal elevation. Thus, the iatrogenic chorioretinal damage caused by visible endpoint photocoagulation may be redundant and an equally effective laser therapy could be administered with minimum intensity photocoagulation (MIP) using laser protocols aiming to create only non-lethal photo-thermal elevations with no intraoperative visible endpoint. It is the purpose of this paper to review laser techniques and clinical protocols that have been utilized to administer retina-sparing MIP treatments that hold the promise of healing the retina while minimizing the iatrogenic harm.

Risk assessment of ritual use of oral dimethyltryptamine (DMT) and harmala alkaloids.

PubMed

Gable, Robert S

2007-01-01

To extend previous reviews by assessing the acute systemic toxicity and psychological hazards of a dimethyltryptamine and beta-carboline brew (ayahuasca/hoasca) used in religious ceremonies. A systematic literature search, supplemented by interviews with ceremony participants. No laboratory animal models were located that tested the acute toxicity or the abuse potential of ayahuasca. Separate animal studies of the median lethal dose of dimethyltryptamine (DMT) and of several harmala alkaloids indicated that a lethal dose of these substances in humans is probably greater than 20 times the typical ceremonial dose. Adverse health effects may occur from casual use of ayahuasca, particularly when serotonergic substances are used in conjunction. DMT is capable of inducing aversive psychological reactions or transient psychotic episodes that resolve spontaneously in a few hours. There was no evidence that ayahuasca has substantial or persistent abuse potential. Long-term psychological benefits have been documented when ayahuasca is used in a well-established social context. A decoction of DMT and harmala alkaloids used in religious ceremonies has a safety margin comparable to codeine, mescaline or methadone. The dependence potential of oral DMT and the risk of sustained psychological disturbance are minimal.

In vitro sensitivity of medically significant Fusarium species to various antimycotics.

PubMed

Sekhon, A S; Padhye, A A; Garg, A K; Ahmad, H; Moledina, N

1994-01-01

Sixteen isolates belonging to Fusarium chlamydosporum (n = 4), Fusarium equiseti (n = 1), Fusarium moniliforme (n = 2), Fusarium oxysporum (n = 3), Fusarium proliferatum (n = 1), and Fusarium solani (n = 5) were tested against amphotericin B, 5-fluorocytosine, fluconazole, itraconazole, ketoconazole, JAI-amphotericin B (water-soluble compound), hamycin and amphotericin B combined with 5-fluorocytosine, using antibiotic medium M3, high-resolution broth (pH 7.1), Sabouraud's dextrose, and yeast-nitrogen broth media (1 ml/tube). The minimal inhibitory and minimal fungicidal concentrations of 5-fluorocytosine and fluconazole for all species were > 100 micrograms/ml. All Fusarium isolates, except F. equiseti (3.125 micrograms), gave minimal inhibitory concentrations of 12.5-100 micrograms/ml for hamycin. The values for amphotericin B, itraconazole, ketoconazole, JAI-amphotericin B, and amphotericin B combined with 5-fluorocytosine were 1.56-100, 0.78-50, 3.125-100,50-100, and 1.56 to > 100 micrograms/ml, respectively. Although a wide range of minimal inhibitory concentrations was recorded for most of the isolates studied, it appears that some--F. solani, F. oxysporum, F. chlamydosporum, F. equiseti, and F. moliniforme--were more susceptible to amphotericin B, itraconazole, ketoconazole, hamycin, and amphotericin B in the presence of 5-fluorocytosine. All isolates showed resistance to 5-fluorocytosine and fluconazole. The minimal fungicidal concentrations were either the same or several times higher than the minimal inhibitory concentrations.

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

Herkovits, J.; Herkovits, F.D.; Fernandez, A.

The identification of mercurium hazard for Cnesterodon decemmaculatus and Bufo arenarum (embryos) was evaluated in a renewal toxicity test system at 20 C and informed as LC100, LC50 and NOEC for 24 and up till 96 hours of exposure (acute Toxicity Profile -- TPa -- for mercurium). On addition the beneficial effect of zinc against the lethal effect of mercurium is reported. The test with fish were conducted maintaining 10 individuals in 1 L of EPA water (by quadruplicate) in six concentrations of Hg plus controls, while for amphibian, batches of 10 Bufo arenarum embryos at stage 25 (by quadruplicate)more » were maintained in 40 ml of Holtfreter`s solution in six concentration of Hg + (HgCl) plus controls. The LC100, LC50 and NOEC for fishes expressed in Hg (+) mg/L were: 0.60, 0.25 and 0.10 for 24 hours of exposure. These values increased very slightly at least up till 96 hours of exposure. Therefore, Bufo arenarum seems to be about three times more sensitive than Cnesterodon decemmaculatus to mercurium. By means of simultaneous mercurium-zinc treatment (ZnSO4) the lethal effect of mercurium could be reduced in amphibians up till 100% with 18 mg Zn2+/L, while for the fish the best result obtained was a reduction of about 50% of lethality within the first 96 hours of treatment with 20 mg Zn2+/L. As a whole the results point out the high susceptibility of amphibian embryos to xenobiotics, the beneficial effect of zinc against embryos to xenobiotics, the beneficial effect of zinc against toxicity exerted by Hg and the need of biological test systems for recording the combined effects of substances released to the environment.« less

[Biodistribution and Postmortem Redistribution of Emamectin Benzoate in Intoxicated Mice].

PubMed

Tang, Wei-wei; Lin, Yu-cai; Lu, Yan-xu

2016-02-01

To investigate the lethal blood level, the target organs and tissues, the toxicant storage depots and the postmortem redistribution in mice died of emamectin benzoate poisoning. The mice model of emamectin benzoate poisoning was established via intragastric injection. The main poisoning symptoms and the clinical death times of mice were observed and recorded dynamically in the acute poisoning group as well as the sub-acute poisoning death group. The pathological and histomorphological changes of organs and tissues were observed after poisoning death. The biodistribution and postmortem redistribution of emamectin benzoate in the organs and tissues of mice were assayed by the enzyme-linked immunosorbent assay (ELISA) at 0h, 24h, 48h and 72h after death. The lethal blood concentrations and the concentrations of emamectin benzoate were detected by high performance liquid chromatography (HPLC) at different time points after death. The symptoms of nervous and respiratory system were observed within 15-30 min after intragastric injection. The average time of death was (45.8 ± 7.9) min in the acute poisoning group and (8.0 ± 1.4) d in the sub-acute poisoning group, respectively. The range of acute lethal blood level was 447.164 0-524.463 5 mg/L. The pathological changes of the organs and tissues were observed via light microscope and immunofluorescence microscope. The changes of emamectin benzoate content in the blood, heart, liver, spleen, lung, kidney and brain of poisoning mice showed regularity within 72 h after death (P < 0.05). The target organs of emamectin benzoate poisoning include heart, liver, kidney, lung, brain and contact position (stomach). The toxicant storage depots are kidney and liver. There is emamectin benzoate postmortem redistribution in mice.

Toxic and genotoxic effects of the imazethapyr-based herbicide formulation Pivot H® on montevideo tree frog Hypsiboas pulchellus tadpoles (Anura, Hylidae).

PubMed

Pérez-Iglesias, J M; Soloneski, S; Nikoloff, N; Natale, G S; Larramendy, M L

2015-09-01

Acute lethal and sublethal toxicity of the imidazolinone imazethapyr (IMZT)-based commercial formulation herbicide Pivot H® (10.59% IMZT) was evaluated on Hypsiboas pulchellus tadpoles. Whereas mortality was used as the end point for lethality, frequency of micronuclei (MNs) and other nuclear abnormalities as well as DNA single-strand breaks evaluated by the single cell gel electrophoresis assay were employed to test genotoxicity. Behavioral, growth, developmental, and morphological abnormalities were also employed as sublethal end points. Mortality studies revealed equivalent LC50 (96h) values of 1.49mg/L (confidence limit, 1.09-1.63) and 1.55mg/L (confidence limit, 1.51-1.60) IMZT for Gosner stage (GS) 25 and GS36, respectively. Behavioral changes, i.e., irregular swimming and immobility, as well as a decreased frequency of keratodonts were observed. The herbicide increased the frequency of MNs in circulating erythrocytes of tadpoles exposed for 48h to the highest concentration assayed (1.17mg/L). However, regardless of the concentration of the herbicide assayed, an enhanced frequency of MNs was observed in tadpoles exposed for 96h. The herbicide was able to induce other nuclear abnormalities, i.e., blebbed and notched nuclei, only when tadpoles were exposed for 96h. In addition, we observed that exposure to IMZT within the 0.39-1.17mg/L range increased the genetic damage index in treatments lasting for both 48 and 96h. This study represents the first evidence of acute lethal and sublethal effects exerted by IMZT on amphibians. Finally, our findings highlight the properties of this herbicide that jeopardize nontarget living species exposed to IMZT. Copyright © 2015 Elsevier Inc. All rights reserved.

Effect of in vitro and in vivo organotin exposures on the immune functions of murray cod (Maccullochella peelii peelii).

PubMed

Harford, Andrew J; O'Halloran, Kathryn; Wright, Paul E A

2007-08-01

Murray cod (Maccullochella peelii peelii) is an iconic native Australian freshwater fish and an ideal species for ecotoxicological testing of environmental pollutants. The species is indigenous to the Murray-Darling basin, which is the largest river system in Australia but also the ultimate sink for many environmental pollutants. The organotins tributyltin (TBT) and dibutyltin (DBT) are common pollutants of both freshwater and marine environments and are also known for their immunotoxicity in both mammals and aquatic organisms. In this study, TBT and DBT were used as exemplar immunotoxins to assess the efficiency of immune function assays (i.e., mitogen-stimulated lymphoproliferation, phagocytosis in head kidney tissue, and serum lysozyme activity) and to compare the sensitivity of Murray cod to other fish species. The organotins were lethal to Murray cod at concentrations previously reported as sublethal in rainbow trout (i.e., intraperitoneal [i.p.] lethal dose to 75% of the Murray cod [LD75] = 2.5 mg/kg DBT and i.p. lethal dose to 100% of the Murray cod [LD100] = 12.5 mg/kg TBT and DBT). In vivo TBT exposure at 0.1 and 0.5 mg/kg stimulated the phagocytic function of Murray cod (F = 6.89, df = 18, p = 0.004), while the highest concentration of 2.5 mg/kg TBT decreased lymphocyte numbers (F = 7.92, df = 18, p = 0.02) and mitogenesis (F = 3.66, df = 18, p = 0.035). Dibutyltin was the more potent immunosuppressant in Murray cod, causing significant reductions in phagocytic activity (F = 5.34, df = 16, p = 0.013) and lymphocyte numbers (F = 10.63, df = 16, p = 0.001).

Biotransfer, bioaccumulation and effects of herbivore dietary Co, Cu, Ni, and Zn on growth and development of the insect predator Podisus maculiventris (Say).

PubMed

Cheruiyot, Dorothy J; Boyd, Robert S; Coudron, Thomas A; Cobine, Paul A

2013-06-01

Increased metal availability in the environment can be detrimental for the growth and development of all organisms in a food web. In part, this toxicity is due to biotransfer or bioaccumulation of metals between trophic levels. We evaluated the survival, growth, and development of a generalist Hemipteran predator (Podisus maculiventris) when fed herbivorous prey (Spodoptera exigua) reared on artificial diet amended with Cu, Zn, Ni, and Co. Predator nymphs were fed S. exigua larvae raised on diet amended with sublethal (Minimum Sublethal Concentration or MSC) or lethal (Minimum Lethal Concentration or MLC) concentrations of each metal, as well as control diet. We determined if metals were biotransferred or bioaccumulated from the diet to herbivore and predator, as well as if predator growth or survival was affected by herbivore diet. Podisus maculiventris fed herbivores raised on MLC levels of both Cu and Zn took significantly longer to mature to adults, whereas their overall survival was not affected by prey diet metal concentration for any metal. Adult weights were significantly reduced for predators raised on herbivores reared on diets amended with the MLC of Cu and Zn. Copper and Zn were bioaccumulated from diet to herbivore and from herbivore to predator, whereas Ni was biotransferred (although concentrations decreased as trophic level increased). The pattern for Co was more complex, with biotransfer the main outcome. Our results show that availability of metals in a food web can affect growth and development of a hemipteran predator, and that metals are transferred between trophic levels, with metal-specific biotransfer and bioaccumulation outcomes.

Identification and evaluation of a new entomopathogenic fungal strain against Riptortus pedestris (Hemiptera: Alydidae) and its two egg parasitoids

PubMed Central

Lim, Un Taek

2018-01-01

A strain (ARP14) of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was isolated from field-collected Riptortus pedestris (Fabricius) (Hemiptera: Alydidae). The lethal median concentration of the ARP14 strain was compared with that of a commercialized strain (GHA) of the same fungus against R. pedestris and its two egg parasitoids, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae). Mortality and mycosis rates were evaluated after exposure to five concentrations of the fungus, i.e., 1×109, 1×108, 1×107, 1×106, and 1×105 conidia/mL, using a glass scintillation vial as an exposure arena in 25.0 ± 0.5°C and 93.7 ± 2.9% RH. The lethal median concentrations (LC50) for 2nd and 4th instar nymphs, and adults of R. pedestris were not significantly different between the two strains of B. bassiana. However, the mycosis rate of ARP14 was 1.3 and 1.8 times higher than that of the GHA strain in 4th instar nymphs and adult females of R. pedestris, respectively, at the 1×108 conidia/mL concentration. More interestingly, the mycosis rates at 1×108 conidia/mL concentration in the parasitoids G. japonicum and O. nezarae were much lower in the ARP14 strain (15.0 and 0%) than in the GHA strain (73.3 and 66.0%), respectively, suggesting that the B. bassiana strain ARP14 is less virulent to these parasitoids than the commercially available strain. Our results suggest that B. bassiana ARP14 may be a potential new biopesticide against R. pedestris with fewer negative effects on beneficial parasitoids than currently available options. PMID:29664929

Comparative assessment of three in vitro exposure methods for combustion toxicity.

PubMed

Lestari, Fatma; Markovic, Boban; Green, Anthony R; Chattopadhyay, Gautam; Hayes, Amanda J

2006-01-01

A comparative assessment of three approaches for the use of human cells in vitro to investigate combustion toxicity was conducted. These included one indirect and two direct (passive and dynamic) exposure methods. The indirect method used an impinger system in which culture medium was used to trap the toxicants, whilst the direct exposure involved the use of a Horizontal Harvard Navicyte Chamber at the air/liquid interface. The cytotoxic effects of thermal decomposition products were assessed using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay (Promega) on a selection of human cells including: HepG2, A549 and skin fibroblasts. A small scale laboratory fire test using a vertical tube furnace was designed for the generation of combustion products. Polymethyl methacrylate (PMMA) was selected as a model polymer to study the cytotoxic effects of combustion products. NOAEC (no observable adverse effect concentration), IC10 (10% inhibitory concentration), IC50 (50% inhibitory concentration) and TLC (total lethal concentration) values were determined from dose response curves. Assessment using the NRU (neutral red uptake) and ATP (adenosine triphosphate) assays on human lung derived cells (A549) was also undertaken. Comparison between in vitro cytotoxicity results against published toxicity data for PMMA combustion and predicted LC50 (50% lethal concentration) values calculated from identified compounds using GCMS (gas chromatography mass spectrometry) was determined. The results suggested that the indirect exposure method did not appear to simulate closely exposure via inhalation, whilst exposure at the air/liquid interface by using the dynamic method proved to be a more representative method of human inhalation. This exposure method may be a potential system for in vitro cytotoxicity testing in combustion toxicity. Copyright 2005 John Wiley & Sons, Ltd.

Identification and evaluation of a new entomopathogenic fungal strain against Riptortus pedestris (Hemiptera: Alydidae) and its two egg parasitoids.

PubMed

Dangi, Naresh; Lim, Un Taek

2018-01-01

A strain (ARP14) of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was isolated from field-collected Riptortus pedestris (Fabricius) (Hemiptera: Alydidae). The lethal median concentration of the ARP14 strain was compared with that of a commercialized strain (GHA) of the same fungus against R. pedestris and its two egg parasitoids, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae). Mortality and mycosis rates were evaluated after exposure to five concentrations of the fungus, i.e., 1×109, 1×108, 1×107, 1×106, and 1×105 conidia/mL, using a glass scintillation vial as an exposure arena in 25.0 ± 0.5°C and 93.7 ± 2.9% RH. The lethal median concentrations (LC50) for 2nd and 4th instar nymphs, and adults of R. pedestris were not significantly different between the two strains of B. bassiana. However, the mycosis rate of ARP14 was 1.3 and 1.8 times higher than that of the GHA strain in 4th instar nymphs and adult females of R. pedestris, respectively, at the 1×108 conidia/mL concentration. More interestingly, the mycosis rates at 1×108 conidia/mL concentration in the parasitoids G. japonicum and O. nezarae were much lower in the ARP14 strain (15.0 and 0%) than in the GHA strain (73.3 and 66.0%), respectively, suggesting that the B. bassiana strain ARP14 is less virulent to these parasitoids than the commercially available strain. Our results suggest that B. bassiana ARP14 may be a potential new biopesticide against R. pedestris with fewer negative effects on beneficial parasitoids than currently available options.

Individual and Combined Effects of Bacillus Thuringiensis and Azadirachtin on Plodia Interpunctella Hübner (Lepidoptera: Pyralidae)

PubMed Central

Nouri-Ganbalani, Gadir; Borzoui, Ehsan; Abdolmaleki, Arman; Abedi, Zahra; George Kamita, Shizuo

2016-01-01

The Indianmeal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae), is a major stored product pest that is found throughout the world. In this study, the effect of oral exposure to Bacillus thuringiensis (Berliner) subsp. kurstaki (Bacillales: Bacillaceae) and azadirachtin was evaluated in third instar P. interpunctella under laboratory conditions. The median lethal concentration (LC50) of Bt and azadirachtin on third instars was 490 and 241 μg a.i./ml, respectively. The median lethal time (LT50) of these insecticides was the same (4.5 d following exposure to 750 or 400 μg a.i./ml of Bt or azadirachtin, respectively). When the larvae fed on diet containing LC30 concentrations of both Bt and azadirachtin an additive interaction in terms of mortality was found. A synergistic interaction was found when the larvae fed on diet containing LC50 concentrations of both insecticides. Larvae that fed on insecticide-containing diet (either Bt or azadirachtin at an LC30 concentration, or both insecticides at LC30 or LC50 concentrations) showed lower glycogen and lipid levels, and generally lower protein content in comparison to control larvae. Larvae that fed on diet containing both Bt and azadirachtin showed reduced weight gain and nutritional indices in comparison to control larvae or larvae fed on the diet containing only one of the insecticides. Finally, exposure to both insecticides, either individually or in combination, reduced the level of digestive enzymes found in the midgut. Our findings indicate that both Bt and azadirachtin, either individually or in combination have significant potential for use in controlling of P. interpunctella. PMID:27638953

Individual and Combined Effects of Bacillus Thuringiensis and Azadirachtin on Plodia Interpunctella Hübner (Lepidoptera: Pyralidae).

PubMed

Nouri-Ganbalani, Gadir; Borzoui, Ehsan; Abdolmaleki, Arman; Abedi, Zahra; George Kamita, Shizuo

2016-01-01

The Indianmeal moth, Plodia interpunctella Hübner (Lepidoptera: Pyralidae), is a major stored product pest that is found throughout the world. In this study, the effect of oral exposure to Bacillus thuringiensis (Berliner) subsp. kurstaki (Bacillales: Bacillaceae) and azadirachtin was evaluated in third instar P. interpunctella under laboratory conditions. The median lethal concentration (LC50) of Bt and azadirachtin on third instars was 490 and 241 μg a.i./ml, respectively. The median lethal time (LT50) of these insecticides was the same (4.5 d following exposure to 750 or 400 μg a.i./ml of Bt or azadirachtin, respectively). When the larvae fed on diet containing LC30 concentrations of both Bt and azadirachtin an additive interaction in terms of mortality was found. A synergistic interaction was found when the larvae fed on diet containing LC50 concentrations of both insecticides. Larvae that fed on insecticide-containing diet (either Bt or azadirachtin at an LC30 concentration, or both insecticides at LC30 or LC50 concentrations) showed lower glycogen and lipid levels, and generally lower protein content in comparison to control larvae. Larvae that fed on diet containing both Bt and azadirachtin showed reduced weight gain and nutritional indices in comparison to control larvae or larvae fed on the diet containing only one of the insecticides. Finally, exposure to both insecticides, either individually or in combination, reduced the level of digestive enzymes found in the midgut. Our findings indicate that both Bt and azadirachtin, either individually or in combination have significant potential for use in controlling of P. interpunctella. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Susceptibility of four tick species, Amblyomma americanum, Dermacentor variabilis, Ixodes scapularis, and Rhipicephalus sanguineus (Acari: Ixodidae), to nootkatone from essential oil of grapefruit.

PubMed

Flor-Weiler, Lina B; Behle, Robert W; Stafford, Kirby C

2011-03-01

Toxicity of nootkatone was determined in laboratory assays against unfed nymphs of Amblyomma americanum L., Dermacentor variabilis (Say), Ixodes scapularis Say, and Rhipicephalus sanguineus Latreille. We determined the 50% lethal concentration (LC50) and 90% lethal concentration (LC90) of nootkatone by recording tick mortality 24 h after exposure in treated glass vials. Nymphs were susceptible to nootkatone with LC50 values of 0.352, 0.233, 0.169, and 0.197 microg/cm2, and LC90 values of 1.001, 0.644, 0.549, and 0.485 microg/cm2 for A. americanum, D. variabilis, I. scapularis, and R. sanguineus, respectively. The LC50 value for R. sanquineus was not significantly different from D. variabilis or I. scapularis. Other LC50 comparisons were significantly different. The LC90 for A. americanum was higher when compared with the three other tick species, which were not significantly different. Because nootkatone is volatile, we measured the amount of nootkatone recovered from duplicate-treated vials before tick exposure and from vials after tick exposure. Nootkatone recovered from vials before exposure ranged from 82 to 112% of the expected amounts. The nootkatone recovered after the 24-h exposure period ranged from 89% from vials coated with higher concentrations of nootkatone, down to 29% from vials coated with low nootkatone concentrations. Determination of the nootkatone residue after vial coating demonstrated loss of the active compound while verifying the levels of tick exposure. Toxicity of low concentrations of nootkatone to the active questing stage of ticks reported in this study provides a reference point for future formulation research to exploit nootkatone as a safe and environment-friendly tick control.

Molecular Control of TiO2-NPs Toxicity Formation at Predicted Environmental Relevant Concentrations by Mn-SODs Proteins

PubMed Central

Wu, Qiuli; Li, Yiping; Tang, Meng; Ye, Boping; Wang, Dayong

2012-01-01

With growing concerns of the safety of nanotechnology, the in vivo toxicity of nanoparticles (NPs) at environmental relevant concentrations has drawn increasing attentions. We investigated the possible molecular mechanisms of titanium nanoparticles (Ti-NPs) in the induction of toxicity at predicted environmental relevant concentrations. In nematodes, small sizes (4 nm and 10 nm) of TiO2-NPs induced more severe toxicities than large sizes (60 nm and 90 nm) of TiO2-NPs on animals using lethality, growth, reproduction, locomotion behavior, intestinal autofluorescence, and reactive oxygen species (ROS) production as endpoints. Locomotion behaviors could be significantly decreased by exposure to 4-nm and 10-nm TiO2-NPs at concentration of 1 ng/L in nematodes. Among genes required for the control of oxidative stress, only the expression patterns of sod-2 and sod-3 genes encoding Mn-SODs in animals exposed to small sizes of TiO2-NPs were significantly different from those in animals exposed to large sizes of TiO2-NPs. sod-2 and sod-3 gene expressions were closely correlated with lethality, growth, reproduction, locomotion behavior, intestinal autofluorescence, and ROS production in TiO2-NPs-exposed animals. Ectopically expression of human and nematode Mn-SODs genes effectively prevented the induction of ROS production and the development of toxicity of TiO2-NPs. Therefore, the altered expression patterns of Mn-SODs may explain the toxicity formation for different sizes of TiO2-NPs at predicted environmental relevant concentrations. In addition, we demonstrated here a strategy to investigate the toxicological effects of exposure to NPs upon humans by generating transgenic strains in nematodes for specific human genes. PMID:22973466

Physiological stress and ethanol accumulation in tree stems and woody tissues at sublethal temperatures from fire

Treesearch

Rick G. Kelsey; Douglas J. Westlind

2017-01-01

The lethal temperature limit is 60 degrees Celsius (°C) for plant tissues, including trees, with lower temperatures causing heat stress. As fire injury increases on tree stems, there is an accompanying rise in tissue ethanol concentrations, physiologically linked to impaired mitochondrial oxidative phosphorylation energy production. We theorize that sublethal tissue...

Transmission electron microscopy study of Listeria monocytogenes serotype 1/2a cells exposed to sublethal heat stress and carvacrol

USDA-ARS?s Scientific Manuscript database

The objective of this study was to investigate the morphological changes that occurred in Listeria monocytogenes serotype 1/2a cells as visualized by transmission electron microscopy (TEM) after exposure to sublethal heat stress at 48°C for 60 min and in combination with lethal concentration of carv...

Estimation of median lethal concentration of three isolates of Beauveria bassiana for control of Megacopta cribraria (Heteroptera: Plataspidae) bioassayed on solid Lugys Spp. Diet²

USDA-ARS?s Scientific Manuscript database

The entomopathogenic fungus Beauveria bassiana is a potential candidate for biological control of a variety of pests. The objectives of this study were isolate and identify the fungus from Kudzu bugs and determine its infectivity comparing with two highly pathogenic isolates including the Mississipp...

Effects of dietary exposure to forest pesticides on the brown garden snail Helix aspersa mueller

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

Schuytema, G.S.; Nebeker, A.V.; Griffis, W.L.

1994-01-01

Brown garden snails, Helix aspersa, were fed prepared diets with 12 pesticides used in forest spraying practices where endangered arboreal and terrestrial snails may be at risk. Acephate, atrazine, glyphosate, hexazinone, and picloram were not lethal at concentrations of 5,000 mg/kg in 14-day screening tests. The remaining seven pesticides, lethal to 13-100% of the tested snails at 5,000 mg/kg, were evaluated in 10-day definitive feeding tests. Azinphosmethyl (Guthion) and aminocarb were the most toxic, with 10-day LC50s of 188 and 313 mg/kg, respectively. Paraquat, trichlorfon and fenitrothion had 10-day LC50s of 659, 664, and 7,058 mg/kg respectively. Avoidance of pesticide-containingmore » foods occurred, e.g., 10-day LC50s of >10,000 mg/kg for carbaryl and ethyl parathion. Significant descreases (p<0.05) in snail weight (total, shell-only, body-only) or shell diameter were accompanied by a significant decrease in the amount of food consumed/snail/day. Concentrations of pesticide in tissues were measured in snails exposed to atrazine and azinphosmethyl; there was no bioaccumulation. (Copyright (c) 1994 Springer-Verlag New York Inc.)« less

Cardiomyocyte H9c2 cells present a valuable alternative to fish lethal testing for azoxystrobin.

PubMed

Rodrigues, Elsa T; Pardal, Miguel Â; Laizé, Vincent; Cancela, M Leonor; Oliveira, Paulo J; Serafim, Teresa L

2015-11-01

The present study aims at identifying, among six mammalian and fish cell lines, a sensitive cell line whose in vitro median inhibitory concentration (IC50) better matches the in vivo short-term Sparus aurata median lethal concentration (LC50). IC50s and LC50 were assessed after exposure to the widely used fungicide azoxystrobin (AZX). Statistical results were relevant for most cell lines after 48 h of AZX exposure, being H9c2 the most sensitive cells, as well as the ones which provided the best prediction of fish toxicity, with a LC50,96h/IC50,48h = 0.581. H9c2 cell proliferation upon 72 h of AZX exposure revealed a LC50,96h/IC50,72h = 0.998. Therefore, identical absolute sensitivities were attained for both in vitro and in vivo assays. To conclude, the H9c2 cell-based assay is reliable and represents a suitable ethical alternative to conventional fish assays for AZX, and could be used to get valuable insights into the toxic effects of other pesticides. Copyright © 2015 Elsevier Ltd. All rights reserved.

Respiratory responses of the air-breathing fish Hoplosternum littorale to hypoxia and hydrogen sulfide.

PubMed

Affonso, E G; Rantin, F T

2005-07-01

The present study analyzes the respiratory responses of the neotropical air-breathing fish Hoplosternum littorale to graded hypoxia and increased sulfide concentrations. The oxygen uptake (VO2), critical O2 tension (PcO2), respiratory (fR) and air-breathing (fRA) frequencies in response to graded hypoxia were determined for fish acclimated to 28 degrees C. H. littorale was able to maintain a constant VO2 down to a PcO2 of 50 mm Hg, below which fish became dependent on the environmental O2 even with significant increases in fR. The fRA was kept constant around 1 breath h(-1) above 50 mm Hg and increased significantly below 40 mm Hg, reaching maximum values (about 4.5 breaths h(-1)) at 10 mm Hg. The lethality to sulfide concentrations under normoxic and hypoxic conditions were also determined along with the fRA. For the normoxic fish the sulfide lethal limit was about 70 microM, while in the hypoxic ones this limit increased to 87 muM. The high sulfide tolerance of H. littorale may be attributed to the air-breathing capability, which is stimulated by this compound.

Gray bats and pollution in Missouri and northern Alabama

USGS Publications Warehouse

Clark, D.R.; Bunck, C.M.; Cromartie, E.; LaVal, R.K.; Tuttle, M.D.

1981-01-01

Gray bats died with lethal brain concentrations of dieldrin and rising levels of heptachlor epoxide in 1976, 1977, and 1978 at Bat Caves No. 2-3, Franklin County, Missouri. The colony disappeared in 1979. Dieldrin was banned in 1974 and 1981 was the last year for heptachlor use in Missouri. The State is recommendiing three organophosphates (chlorpyrifos or Dursban, dyfonate or Fonophos, and ethoprop or Mocap) as substitutes for heptachlor. All three compounds have excellent records in the environment. Analyses of insects collected where bats of this colony fed showed beetles, particularly rove beetles (Staphylinidae), to be the most heavily contaminated part of the bat's diet. Lactation concentrated these residues so that levels in milk were approximately 30 times those in the insect diet. Gray bats found dead in caves in northern Alabama showed DDD (a DDT derivative) contamination. Bats from the colony at Cave Springs Cave on the Wheeler National Wildlife Refuge contained up to 29 ppm DDD in their brains, but this is probably less than one-half the lethal level. Bats from other colonies contained less. The DDD contamination enters the Terinessee River just above the Wheeler Refuge and is seen in gray bat colonies as far as 60 miles downriver.

Non-Lethal Weapons Program

Science.gov Websites

), 26th Marine Expeditionary Unit (MEU), practice non-lethal control techniques during a non-lethal Skip to main content (Press Enter). Toggle navigation Non-Lethal Weapons Program Search Search JNLWP: Search Search JNLWP: Search Non-Lethal Weapons Program U.S. Department of Defense Non-Lethal

[Bladder tumor lethality. Results in the autonomous community of Rioja between 1975-1991].

PubMed

Fernández Fernández, A; Gil Fabra, J; Fernández Ruíz, M; Angulo Castellanos, M G; Blanco Martín, E; Otero Mauricio, G

1998-01-01

Between 1975-1991, a total of 557 cases of bladder carcinoma were identified in the Autonomous Community of La Rioja (CAR) which were followed up to December 1994. The overall lethality was 21.9%. 492 cases with 22.35% lethality were identified in males. In females, however, there was 65 cases with 18.46% lethality. The comparison of males and females lethality resulted in p = 0.525. Lethality between cases diagnosed within each 5-year period analyzed is: 1975-1981: 177 cases, lethality 23.72%. 1982-1986: 168 cases, lethality 30.95%. 1987-1991: 212 cases, lethality 13.20%. Between the first and the second 5-year periods, p = 0.132; between the first and third 5-year periods p = 0.007 and between the second and third 5-year periods p < 0.000. Bladder tumours accounts in CAR for a 22.35% lethality. Lethality is higher in males that in females but the difference is not statistically significant. In the last 5-year period assessed, 1987-1991, a reduction of lethality from bladder neoplasms has been documented.

Selective reconstitution of liver cholesterol biosynthesis promotes lung maturation but does not prevent neonatal lethality in Dhcr7 null mice.

PubMed

Yu, Hongwei; Li, Man; Tint, G Stephen; Chen, Jianliang; Xu, Guorong; Patel, Shailendra B

2007-04-04

Targeted disruption of the murine 3beta-hydroxysterol-Delta7-reductase gene (Dhcr7), an animal model of Smith-Lemli-Opitz syndrome, leads to loss of cholesterol synthesis and neonatal death that can be partially rescued by transgenic replacement of DHCR7 expression in brain during embryogenesis. To gain further insight into the role of non-brain tissue cholesterol deficiency in the pathophysiology, we tested whether the lethal phenotype could be abrogated by selective transgenic complementation with DHCR7 expression in the liver. We generated mice that carried a liver-specific human DHCR7 transgene whose expression was driven by the human apolipoprotein E (ApoE) promoter and its associated liver-specific enhancer. These mice were then crossed with Dhcr7+/- mutants to generate Dhcr7-/- mice bearing a human DHCR7 transgene. Robust hepatic transgene expression resulted in significant improvement of cholesterol homeostasis with cholesterol concentrations increasing to 80~90 % of normal levels in liver and lung. Significantly, cholesterol deficiency in brain was not altered. Although late gestational lung sacculation defect reported previously was significantly improved, there was no parallel increase in postnatal survival in the transgenic mutant mice. The reconstitution of DHCR7 function selectively in liver induced a significant improvement of cholesterol homeostasis in non-brain tissues, but failed to rescue the neonatal lethality of Dhcr7 null mice. These results provided further evidence that CNS defects caused by Dhcr7 null likely play a major role in the lethal pathogenesis of Dhcr7-/- mice, with the peripheral organs contributing the morbidity.

Plasma Potassium Determines NCC Abundance in Adult Kidney-Specific γENaC Knockout.

PubMed

Boscardin, Emilie; Perrier, Romain; Sergi, Chloé; Maillard, Marc P; Loffing, Johannes; Loffing-Cueni, Dominique; Koesters, Robert; Rossier, Bernard C; Hummler, Edith

2018-03-01

The amiloride-sensitive epithelial sodium channel (ENaC) and the thiazide-sensitive sodium chloride cotransporter (NCC) are key regulators of sodium and potassium and colocalize in the late distal convoluted tubule of the kidney. Loss of the α ENaC subunit leads to a perinatal lethal phenotype characterized by sodium loss and hyperkalemia resembling the human syndrome pseudohypoaldosteronism type 1 (PHA-I). In adulthood, inducible nephron-specific deletion of α ENaC in mice mimics the lethal phenotype observed in neonates, and as in humans, this phenotype is prevented by a high sodium (HNa + )/low potassium (LK + ) rescue diet. Rescue reflects activation of NCC, which is suppressed at baseline by elevated plasma potassium concentration. In this study, we investigated the role of the γ ENaC subunit in the PHA-I phenotype. Nephron-specific γ ENaC knockout mice also presented with salt-wasting syndrome and severe hyperkalemia. Unlike mice lacking α ENaC or β ΕΝaC, an HNa + /LK + diet did not normalize plasma potassium (K + ) concentration or increase NCC activation. However, when K + was eliminated from the diet at the time that γ ENaC was deleted, plasma K + concentration and NCC activity remained normal, and progressive weight loss was prevented. Loss of the late distal convoluted tubule, as well as overall reduced β ENaC subunit expression, may be responsible for the more severe hyperkalemia. We conclude that plasma K + concentration becomes the determining and limiting factor in regulating NCC activity, regardless of Na + balance in γ ENaC-deficient mice. Copyright © 2018 by the American Society of Nephrology.

Multistep bioassay to predict recolonization potential of emerging parasitoids after a pesticide treatment.

PubMed

Desneux, Nicolas; Ramirez-Romero, Ricardo; Kaiser, Laure

2006-10-01

Neurotoxic pyrethroid insecticides are widely used for crop protection, and lethal and sublethal perturbations can be expected in beneficial insects. Under laboratory conditions, the lethal and sublethal effects of deltamethrin on the aphid parasitoid Diaeretiella rapae M'Intosh (Hymenoptera: Braconidae) were studied at the mummy stage and in emerging adults. Following a multistep bioassay, analyses were aimed at evaluating the effects of deltamethrin at various crucial steps in the recolonization process following a deltamethrin treatment: Parasitoid pupal development (emergence from the mummies), adult survival, and host-searching capacity. A four-armed olfactometer was used to investigate the effect of deltamethrin on host-searching behavior (a range of concentrations causing 0.4-79.4% mortality was tested), and a Potter tower was used to test the deltamethrin effect with a realistic application method (four concentrations were tested: 0.5, 5.0, 6.25, and 50 g active ingredient [a.i.]/ha). Deltamethrin reduced the percentage of emergence from mummies, but only when exposed to the 50 g a.i./ha concentration. However, for all concentrations tested, the insecticide induced a decrease in longevity after emergence from sprayed mummies and significant adult mortality when parasitoids walked on fresh residues on leaves. Indices were defined and predicted a high mortality and, thus, reduction of recolonization capacities. However, deltamethrin had no effect on orientation behavior toward aphid-infested plants for adults that survived a residual exposure to the insecticide. The impact of deltamethrin on recolonization via pupal emergence and interest in the methodology used are discussed.

Effect of clavulanic acid on minimal inhibitory concentrations of 16 antimicrobial agents tested against Legionella pneumophila.

PubMed Central

Pohlod, D J; Saravolatz, L D; Quinn, E L; Somerville, M M

1980-01-01

A total of 15 Legionella pneumophilia isolated were tested against 16 antimicrobial agents used singly and in combination with clavulanic acid. When combined with clavulanic acid, 4 of the 16 antimicrobial agents produced no enhanced effect. However, the minimal inhibitory concentrations of 12 of the antimicrobial agents were reduced by one-half to one-third when in combination with clavulanic acid. These reductions reflected only a one-dilution decrease, however, in the original minimal inhibitory concentrations. Thus, clavulanic acid combinations appear to be only nominally effective beta-lactamase inhibitors against L. pneumophilia. PMID:6969575

Acute oral toxicity of colchicine in rats: effects of gender, vehicle matrix and pre-exposure to lipopolysaccharide.

PubMed

Wiesenfeld, Paddy L; Garthoff, Larry H; Sobotka, Thomas J; Suagee, Jessica K; Barton, Curtis N

2007-01-01

The oral toxicity of a single administration by gavage (10, 20 or 30 mg kg(-1) body weight) of colchicine (COL) was determined in young, mature male and female Sprague-Dawley rats. The effect of COL was evaluated in the presence or absence of additional treatment variables that included vehicle and lipopolysaccharide (LPS) pre-exposure. The vehicle for COL was either Half and Half cream (H & H) or saline, and each group included pretreatment with either saline or a low, minimally toxic dose (83 microg kg(-1) body weight) of LPS. Colchicine toxicity in both male and female age-matched rats was characterized by progressively more severe dose-related clinical signs of toxicity. These included mortality, decreased body weight and feed intake during the first several days after dosing, with recovery thereafter in surviving animals. There were differences in the severity of the toxic response to COL between male and female rats. The most notable sex-related difference was in COL lethality. Female rats were two times more susceptible to the lethal effects of COL than male rats. Saline or H & H delivery vehicles did not result in any apparent qualitative or quantitative differences in COL toxicity. LPS pretreatment significantly potentiated COL lethality in both males and females, although the potentiation in males was greater than in females. LPS pretreatment modestly increased the COL induced anorexic effect in surviving males, but not in surviving female animals. LPS did not appear to modulate either the body weights or clinical signs of COL induced toxicity in surviving males or females. (c) 2007 John Wiley & Sons, Ltd.

Minimal In Vivo Efficacy of Iminosugars in a Lethal Ebola Virus Guinea Pig Model

PubMed Central

Dowall, Stuart D.; Taylor, Irene; Rule, Antony; Alonzi, Dominic S.; Sayce, Andrew C.; Wright, Edward; Bentley, Emma M.; Thom, Ruth; Hall, Graham; Dwek, Raymond A.; Hewson, Roger; Zitzmann, Nicole

2016-01-01

The antiviral properties of iminosugars have been reported previously in vitro and in small animal models against Ebola virus (EBOV); however, their effects have not been tested in larger animal models such as guinea pigs. We tested the iminosugars N-butyl-deoxynojirimycin (NB-DNJ) and N-(9-methoxynonyl)-1deoxynojirimycin (MON-DNJ) for safety in uninfected animals, and for antiviral efficacy in animals infected with a lethal dose of guinea pig adapted EBOV. 1850 mg/kg/day NB-DNJ and 120 mg/kg/day MON-DNJ administered intravenously, three times daily, caused no adverse effects and were well tolerated. A pilot study treating infected animals three times within an 8 hour period was promising with 1 of 4 infected NB-DNJ treated animals surviving and the remaining three showing improved clinical signs. MON-DNJ showed no protective effects when EBOV-infected guinea pigs were treated. On histopathological examination, animals treated with NB-DNJ had reduced lesion severity in liver and spleen. However, a second study, in which NB-DNJ was administered at equally-spaced 8 hour intervals, could not confirm drug-associated benefits. Neither was any antiviral effect of iminosugars detected in an EBOV glycoprotein pseudotyped virus assay. Overall, this study provides evidence that NB-DNJ and MON-DNJ do not protect guinea pigs from a lethal EBOV-infection at the dose levels and regimens tested. However, the one surviving animal and signs of improvements in three animals of the NB-DNJ treated cohort could indicate that NB-DNJ at these levels may have a marginal beneficial effect. Future work could be focused on the development of more potent iminosugars. PMID:27880800

Efficacy of sanitizers in reducing Salmonella on pecan nutmeats during cracking and shelling.

PubMed

Beuchat, Larry R; Mann, David A; Alali, Walid Q

2013-05-01

Studies were done to evaluate the efficacy of chlorine (200 to 1,000 μg/ml), lactic acid (0.5 to 2%), levulinic acid (0.5 to 2%), sodium dodecyl sulfate (SDS, 0.05%), lactic acid plus SDS, levulinic acid plus SDS, and a mixed peroxyacid sanitizer (Tsunami 200, 40 and 80 μg/ml) in killing Salmonella on or in immersion- and on surface-inoculated pecan nutmeats (U.S. Department of Agriculture medium pieces and mammoth halves). The addition of SDS to treatment solutions containing lactic acid or levulinic acid resulted in generally higher reductions of Salmonella, but differences in these reductions were not always significant. Lactic and levulinic acids (2%) containing SDS (0.05%) were equivalent in killing Salmonella on immersion-inoculated nutmeats. Tsunami 200 (40 μg/ml) was less lethal or equivalent to 1 or 2% lactic and levulinic acids, with or without 0.05% SDS. Reductions did not exceed 1.1 log CFU/g of immersion-inoculated pieces and halves, regardless of sanitizer concentration or treatment time (up to 20 min). Reductions on surface-inoculated pieces and halves were 0.7 to 2.6 log CFU/g and 1.2 to 3.0 log CFU/g, respectively. Treatment with 2% lactic acid plus SDS (0.05%) and Tsunami (80 μg/ml) was most effective in killing Salmonella on surface-inoculated pieces; treatment of halves with chlorine (1,000 μg/ml) or lactic acid (1 or 2%), with or without SDS, was most efficacious. Exposure of immersion-inoculated pecan pieces to chlorine (200 μg/ml), lactic acid (2%) and levulinic acid (2%) with or without SDS, and Tsunami (80 μg/ml) during intermittent vacuum (18 ± 2 mbar) and ambient atmospheric pressure treatments for up to 20 min reduced Salmonella by only 0.1 to 1.0 log CFU/g. These studies emphasize the importance of preventing contamination of pecan nutmeats with Salmonella. Once nuts are contaminated, the lethality of sanitizers tested in this study is minimal.

Variation in Extracellular Detoxification Is a Link to Different Carcinogenicity among Chromates in Rodent and Human Lungs.

PubMed

Krawic, Casey; Luczak, Michal W; Zhitkovich, Anatoly

2017-09-18

Inhalation of soluble chromium(VI) is firmly linked with higher risks of lung cancer in humans. However, comparative studies in rats have found a high lung tumorigenicity for moderately soluble chromates but no tumors for highly soluble chromates. These major species differences remain unexplained. We investigated the impact of extracellular reducers on responses of human and rat lung epithelial cells to different Cr(VI) forms. Extracellular reduction of Cr(VI) is a detoxification process, and rat and human lung lining fluids contain different concentrations of ascorbate and glutathione. We found that reduction of chromate anions in simulated lung fluids was principally driven by ascorbate with only minimal contribution from glutathione. The addition of 500 μM ascorbate (∼rat lung fluid concentration) to culture media strongly inhibited cellular uptake of chromate anions and completely prevented their cytotoxicity even at otherwise lethal doses. While proportionally less effective, 50 μM extracellular ascorbate (∼human lung fluid concentration) also decreased uptake of chromate anions and their cytotoxicity. In comparison to chromate anions, uptake and cytotoxicity of respirable particles of moderately soluble CaCrO 4 and SrCrO 4 were much less sensitive to suppression by extracellular ascorbate, especially during early exposure times and in primary bronchial cells. In the absence of extracellular ascorbate, chromate anions and CaCrO 4 /SrCrO 4 particles produced overall similar levels of DNA double-stranded breaks, with less soluble particles exhibiting a slower rate of breakage. Our results indicate that a gradual extracellular dissolution and a rapid internalization of calcium chromate and strontium chromate particles makes them resistant to detoxification outside the cells, which is extremely effective for chromate anions in the rat lung fluid. The detoxification potential of the human lung fluid is significant but much lower and insufficient to provide a threshold-type dose dependence for soluble chromates.

Relative toxicity of the pyrolysis products from some thermoplastic and thermoset polymers

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Gilwee, W. J., Jr.; Hilado, C. J.

1978-01-01

Relative toxicity data on the pyrolysis products of a variety of thermoplastic and thermoset polymers are presented. The data are presented in terms of time to incapacitation and time to death with a fixed sample weight of 1.0 g, and in terms of the apparent lethal concentration required to produce 50 percent mortality within a fixed exposure period of 30 min.

Molybdenum Hazards to Fish, Wildlife, and Invertebrates: A Synoptic Review

USGS Publications Warehouse

Eisler, R.

1989-01-01

Ecological and toxicological aspects of molybdenum (Mo) in the environment are briefly reviewed, with emphasis on fish and wildlife. Subtopics include sources and uses, chemical properties, mode of action, background concentrations in biological and nonbiological samples, and lethal and sublethal effects on terrestrial plants and invertebrates, aquatic organisms, birds, and mammals. Current recommendations for Mo and the protection of sensitive living resources are presented.

Carbon dioxide as an under-ice lethal control for invasive fishes

USGS Publications Warehouse

Cupp, Aaron R.; Woiak, Zebadiah; Erickson, Richard A.; Amberg, Jon J.; Gaikowski, Mark

2017-01-01

Resource managers need effective tools to control invasive fish populations. In this study, we tested under-ice carbon dioxide (CO2) injection as a novel piscicide method for non-native Silver Carp (Hypophthalmichthys molitrix), Bighead Carp (Hypophthalmichthys nobilis), Grass Carp (Ctenopharyngodon idella), Common Carp (Cyprinus carpio) and native Bigmouth Buffalo (Ictiobus cyprinellus). Fish were held overwinter in nine outdoor ponds (0.04 ha surface area; 340,000 L volume) treated with no CO2 (control), 43.5–44.0 kg CO2 (low treatment), and 87.5–88.5 kg CO2 (high treatment). Ponds were harvested immediately after ice-out to assess survival and condition. Resulting survival in low (mean = 32%) and high (mean = 5%) CO2-treated ponds was significantly lower than untreated control ponds (mean = 84%). Lethal efficacy varied across species with no Bighead Carp, Silver Carp, or Bigmouth Buffalo surviving the high CO2 treatment. External infections were observed more frequently after CO2 treatments (means = 49–67%) relative to untreated ponds (mean = 2%), suggesting a secondary mechanism for poor survival. This study demonstrates that CO2 can be used as a lethal control for invasive fishes, but effectiveness may vary by species and CO2concentration.

Photo-activated disinfection based on indocyanine green against cell viability and biofilm formation of Porphyromonas gingivalis.

PubMed

Pourhajibagher, Maryam; Chiniforush, Nasim; Ghorbanzadeh, Roghayeh; Bahador, Abbas

2017-03-01

Photo-activated disinfection (PAD) is a novel treatment approach, in which bacteria in the root canal system may be exposed to sub-lethal doses of PAD. Such exposure can affect bacterial survival and virulence features, such as biofilm formation ability. The aim of this study was to evaluate the effects of sub-lethal doses of PAD (sPAD) using indocyanine green (ICG) on load and biofilm formation ability of Porphyromonas gingivalis as an anaerobic bacterium associated with endodontic infection. The anti-bacterial and anti-biofilm potential of sPAD against P. gingivalis at sub-lethal doses of ICG as a photosensitizer and using 810nm wavelength of diode laser light via colony forming unit and crystal violet assays, respectively, was determined. High concentrations of ICG and light irradiation time significantly reduced bacteria. High doses of sPAD markedly reduced the number of bacteria and the formation of biofilm, up to 30.4% and 25.1%, respectively. High doses of sPAD affected cell viability and the biofilm formation ability of P. gingivalis; lower doses did not. Thus, selection of appropriate PAD dosage should be considered for the successful treatment of endodontic in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

Differences in response of two model estuarine crustaceans after lethal and sublethal exposures to chlorpyrifos.

PubMed

Key, Peter B; Simonik, Elizabeth; Kish, Nicole; Chung, Katy W; Fulton, Michael H

2013-01-01

This study assessed the in vitro and in vivo effects of an acetylcholinesterase enzyme inhibitor (chlorpyrifos) in two estuarine crustaceans: grass shrimp (Palaemonetes pugio) and mysid (Americamysis bahia). The differences in response were quantified after lethal and sublethal exposures to chlorpyrifos and in vitro assays with chlorpyrifos-oxon. Results from the in vitro experiments indicated that the target enzyme, acetylcholinesterase (AChE), in the two species was similar in sensitivity to chlorpyrifos inhibition with IC50s of 0.98 nM and 0.89 nM for grass shrimp and mysids, respectively. In vivo experiments showed that mysids were significantly more sensitive to chlorpyrifos-induced AChE inhibition after 24 h of exposure. The in vivo EC50s for AChE inhibition were 1.23 μg L(-1) for grass shrimp and 0.027 μg L(-1) for mysids. Median lethal concentrations (24h LC50 values) were 1.06 μg L(-1) for grass shrimp and 0.068 μg L(-1) for mysids. The results suggest that differences in the response of these two crustaceans are likely related to differences in uptake and metabolism rather than target site sensitivity.

Insecticidal activity of garlic essential oil and their constituents against the mealworm beetle, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae).

PubMed

Plata-Rueda, Angelica; Martínez, Luis Carlos; Santos, Marcelo Henrique Dos; Fernandes, Flávio Lemes; Wilcken, Carlos Frederico; Soares, Marcus Alvarenga; Serrão, José Eduardo; Zanuncio, José Cola

2017-04-20

This study evaluated the insecticidal activity of garlic, Allium sativum Linnaeus (Amaryllidaceae) essential oil and their principal constituents on Tenebrio molitor. Garlic essential oil, diallyl disulfide, and diallyl sulfide oil were used to compare the lethal and repellent effects on larvae, pupae and adults of T. molitor. Six concentrations of garlic essential oil and their principal constituents were topically applied onto larvae, pupae and adults of this insect. Repellent effect and respiration rate of each constituent was evaluated. The chemical composition of garlic essential oil was also determined and primary compounds were dimethyl trisulfide (19.86%), diallyl disulfide (18.62%), diallyl sulfide (12.67%), diallyl tetrasulfide (11.34%), and 3-vinyl-[4H]-1,2-dithiin (10.11%). Garlic essential oil was toxic to T. molitor larva, followed by pupa and adult. In toxic compounds, diallyl disulfide was the most toxic than diallyl sulfide for pupa > larva > adult respectively and showing lethal effects at different time points. Garlic essential oil, diallyl disulfide and diallyl sulfide induced symptoms of intoxication and necrosis in larva, pupa, and adult of T. molitor between 20-40 h after exposure. Garlic essential oil and their compounds caused lethal and sublethal effects on T. molitor and, therefore, have the potential for pest control.

Insecticidal activity of garlic essential oil and their constituents against the mealworm beetle, Tenebrio molitor Linnaeus (Coleoptera: Tenebrionidae)

PubMed Central

Plata-Rueda, Angelica; Martínez, Luis Carlos; Santos, Marcelo Henrique Dos; Fernandes, Flávio Lemes; Wilcken, Carlos Frederico; Soares, Marcus Alvarenga; Serrão, José Eduardo; Zanuncio, José Cola

2017-01-01

This study evaluated the insecticidal activity of garlic, Allium sativum Linnaeus (Amaryllidaceae) essential oil and their principal constituents on Tenebrio molitor. Garlic essential oil, diallyl disulfide, and diallyl sulfide oil were used to compare the lethal and repellent effects on larvae, pupae and adults of T. molitor. Six concentrations of garlic essential oil and their principal constituents were topically applied onto larvae, pupae and adults of this insect. Repellent effect and respiration rate of each constituent was evaluated. The chemical composition of garlic essential oil was also determined and primary compounds were dimethyl trisulfide (19.86%), diallyl disulfide (18.62%), diallyl sulfide (12.67%), diallyl tetrasulfide (11.34%), and 3-vinyl-[4H]-1,2-dithiin (10.11%). Garlic essential oil was toxic to T. molitor larva, followed by pupa and adult. In toxic compounds, diallyl disulfide was the most toxic than diallyl sulfide for pupa > larva > adult respectively and showing lethal effects at different time points. Garlic essential oil, diallyl disulfide and diallyl sulfide induced symptoms of intoxication and necrosis in larva, pupa, and adult of T. molitor between 20–40 h after exposure. Garlic essential oil and their compounds caused lethal and sublethal effects on T. molitor and, therefore, have the potential for pest control. PMID:28425475

Development of anaesthetic protocols for lumpfish (Cyclopterus lumpus L.): Effect of anaesthetic concentrations, sea water temperature and body weight

PubMed Central

Skår, Malene W.; Powell, Mark D.; Wergeland, Heidrun I.; Samuelsen, Ole B.

2017-01-01

In recent years, use of lumpfish (Cyclopterus lumpus L.) as cleaner-fish to remove sea-lice have been chosen by many salmon farmers in Europe and Canada as an alternative to medical treatment, which has led to large scale production of lumpfish. At present, there is limited knowledge of how lumpfish respond upon anaesthesia, which anaesthetics and concentrations that are efficient and conditions for euthanasia. We have therefore tested and developed protocols for bath immersion for three commonly used anaesthetics metacaine (Finquel, buffered tricaine methanesulfonate, MS-222 and Tricaine Pharmaq), benzocaine (Benzoak vet) and isoeugenol (Aqui-S), determined concentration for normal and fast anaesthesia and evaluated safety margin for each condition. Also, a behavioral matrix has been developed. We have examined the effect of fish size (10–20 g, 200–400 g and 600–1300 g) and sea water temperature (6°C and 12°C). We found that 200 mg L-1 metacaine is an efficient dose for deep narcosis independently for fish size and temperature due to good safety margins with regards to both exposure times and doses. However, for many tasks lighter anaesthesia is sufficient, and then 100 mg L-1 metacaine can be used. Benzocaine is less efficient than metacaine, but can be used as anaesthetic of fish < 400 g. The optimal doses of benzocaine were 100–200 mg L-1 for small fish (10–20 g) and 200 mg L-1 for medium sized fish (200–400 g). For larger fish (> 600 g), benzocaine is not suitable. Isoeugenol cannot be recommended for full anesthesia of lumpfish. The conditions for lethal doses varied with chosen anaesthetic, fish size and temperature. For small fish (10–20 g), exposure to 1600 mgL-1 of metacaine in 10 minutes it lethal. Guided protocols for non-lethal anaesthesia will contribute to ensure safe treatment of lumpfish according to an ethical standard for good fish welfare. PMID:28678815

Toxicologic characterization of a novel explosive, guanidinium 3,4-dinitropyrazolate (GDNP), in female rats and Ames mutagenicity assay.

PubMed

Williams, Larry R; Adams, Valerie H; Wallace, Shannon M; Johnson, Mark S

2012-01-01

Sustainable use of military training ranges requires the development of compounds that have a minimal impact to the environment when used in a weapon system. Guanidinium 3,4-dinitropyrazolate (GDNP) is a novel explosive compound of interest for application in some weapon systems. Little is known of its toxicologic properties. To ensure the health of potentially exposed personnel and the environment, initial toxicity investigations were conducted and the results were compared with another widely used energetic (hexahydro-1,3,5-trinitro-1,3,5-triazine [RDX]). In a microplate Ames assay, GDNP was not cytotoxic to bacterial tester strains at concentrations less than 100 μg/mL. However, GDNP was mutagenic to 4 of 5 bacterial strains with and without S9 metabolic incubation at concentrations as low as 0.7 μg/mL. Unlike RDX, GDNP did not have an affinity for the γ-aminobutyric acid(A) receptor convulsant site and was predicted to not induce seizure. After acute oral dosing in female rats, the median lethal dose in female rats of GDNP in tap water solution was determined to be 720 mg/kg. Daily oral exposure to 500 mg/kg per d of GDNP for 14 days caused weight loss, increased liver and spleen weights, and adverse histopathologic events in kidney and spleen. These adverse events were not observed in animals receiving lower doses of GDNP. In this study, the lowest-observed-adverse-effect-level from oral exposure to GDNP for 14 days was 500 mg/kg per d and the no-observable-adverse-effect-level was 152 mg/kg per d.

Dose-dependent effects of prenatal ethanol exposure in the guinea pig.

PubMed

Catlin, M C; Abdollah, S; Brien, J F

1993-01-01

The guinea pig is an appropriate animal for studying ethanol central nervous system (CNS) teratogenesis due to its extensive prenatal CNS development. In order to establish an ethanol dosage regimen that produces CNS teratogenesis, the objective of this study was to characterize the dose-dependent effects of chronic ethanol administration on pregnancy outcome and locomotor activity of the offspring. Pregnant guinea pigs received one of the following oral treatments, via intubation into the oral cavity, throughout gestation: 3, 4, 5 or 6 g ethanol/kg maternal body weight/day; isocaloric sucrose and pair feeding; or water. The 5 and 6 g ethanol/kg/day regimens produced maternal death, spontaneous abortion, and perinatal death with at least 75% incidence; the 3 and 4 g ethanol/kg/day regimens produced little or no maternal, embryonic/fetal, or perinatal lethality. The 3 and 4 g ethanol/kg/day regimens did not affect other indices of pregnancy outcome compared with the respective isocaloric-sucrose pair-fed control animals and water-treated animals. The 3, 4, and 5 g ethanol/kg/day regimens increased spontaneous locomotor activity in the offspring, and there was a direct relationship between the magnitude of hyperactivity at days 10 and 60 of age and each of the ethanol dosage regimens and the maternal blood ethanol concentration on day 56 of gestation. The data demonstrate that, in the guinea pig, chronic oral administration of ethanol produces: (a) dose-dependent effects on pregnancy outcome, (b) hyperactivity in the offspring that is dose- (and maternal blood ethanol concentration-) and age-related, and (c) persistent hyperactivity into adulthood with minimal toxicity on pregnancy outcome for the 4 g ethanol/kg/day regimen.

The crimson conundrum: heme toxicity and tolerance in GAS

PubMed Central

Sachla, Ankita J.; Le Breton, Yoann; Akhter, Fahmina; McIver, Kevin S.; Eichenbaum, Zehava

2014-01-01

The massive erythrocyte lysis caused by the Group A Streptococcus (GAS) suggests that the β-hemolytic pathogen is likely to encounter free heme during the course of infection. In this study, we investigated GAS mechanisms for heme sensing and tolerance. We compared the minimal inhibitory concentration of heme among several isolates and established that excess heme is bacteriostatic and exposure to sub-lethal concentrations of heme resulted in noticeable damage to membrane lipids and proteins. Pre-exposure of the bacteria to 0.1 μM heme shortened the extended lag period that is otherwise observed when naive cells are inoculated into heme-containing medium, implying that GAS is able to adapt. The global response to heme exposure was determined using microarray analysis revealing a significant transcriptome shift that included 79 up regulated and 84 down regulated genes. Among other changes, the induction of stress-related chaperones and proteases, including groEL/ES (8x), the stress regulators spxA2 (5x) and ctsR (3x), as well as redox active enzymes were prominent. The heme stimulon also encompassed a number of regulatory proteins and two-component systems that are important for virulence. A three-gene cluster that is homologous to the pefRCD system of the Group B Streptococcus was also induced by heme. PefR, a MarR-like regulator, specifically binds heme with stoichiometry of 1:2 and protoporphyrin IX (PPIX) with stoichiometry of 1:1, implicating it is one of the GAS mediators to heme response. In summary, here we provide evidence that heme induces a broad stress response in GAS, and that its success as a pathogen relies on mechanisms for heme sensing, detoxification, and repair. PMID:25414836

Acute toxicity of polyacrylamide flocculants to early life stages of freshwater mussels

USGS Publications Warehouse

Buczek, Sean B.; Cope, W. Gregory; McLaughlin, Richard A.; Kwak, Thomas J.

2017-01-01

Polyacrylamide has become an effective tool for reducing construction-related suspended sediment and turbidity, which are considered to have significant adverse impacts on aquatic ecosystems and are a leading cause of the degradation of North American streams and rivers. However, little is known about the effects of polyacrylamide on many freshwater organisms, and prior to the present study, no information existed on the toxicity of polyacrylamide compounds to native freshwater mussels (family Unionidae), one of the most imperiled faunal groups globally. Following standard test guidelines, we exposed juvenile mussels (test duration 96 h) and glochidia larvae (test duration 24 h) to 5 different anionic polyacrylamide compounds and 1 non-ionic compound. Species tested included the yellow lampmussel (Lampsilis cariosa), an Atlantic Slope species that is listed as endangered in North Carolina; the Appalachian elktoe (Alasmidonta raveneliana), a federally endangered Interior Basin species; and the washboard (Megalonaias nervosa), a common Interior Basin species. We found that median lethal concentrations (LC50s) of polyacrylamide ranged from 411.7 to >1000 mg/L for glochidia and from 126.8 to >1000 mg/L for juveniles. All LC50s were orders of magnitude greater (2–3) than concentrations typically recommended for turbidity control (1–5 mg/L), regardless of their molecular weight or charge density. The results demonstrate that the polyacrylamide compounds tested were not acutely toxic to the mussel species and life stages tested, indicating minimal risk of short-term exposure from polyacrylamide applications in the environment. However, other potential uses of polyacrylamide in the environment (e.g., wastewater treatment, paper processing, mining, algae removal) and their chronic or sublethal effects remain uncertain and warrant additional investigation.

Bioassay-guided isolation and evaluation of antimicrobial compounds from Ixora megalophylla against some oral pathogens.

PubMed

Panyo, J; Matsunami, K; Panichayupakaranant, P

2016-09-01

Context Ixora megalophylla Chamch. (Rubiaceae) is a new plant species recently found in southern Thailand. Ethyl acetate extracts of its leaves and stems showed antimicrobial activities. Objectives To isolate and identify the antimicrobial compounds from I. megalophylla leaves and stems. Materials and methods The dried leaves (1.7 kg) and stems (3.5 kg) were consecutively extracted with petroleum ether (5 L × 4), ethyl acetate (5 L × 3) and ethanol (5 L × 4) under reflux conditions. The ethyl acetate extract was subjected to an antimicrobial assay guided isolation with Candida albicans and Streptococcus mutans. Compounds 1-10 were identified by (1)H NMR, (13)C NMR and EI-MS. Minimal lethal concentration (MLC) against C. albicans and Streptococcus spp. was determined using a broth microdilution method for 48 and 24 h, respectively. Results and discussion On the basis of the antimicrobial assay guided isolation, 10 known compounds, including vanillic acid (1), syringic acid (2), 4-hydroxy benzaldehyde (3), scopoletin (4), loliolide (5), syringaldehyde (6), sinapaldehyde (7), coniferaldehyde (8), syringaresinol (9) and 2,2'-dithiodipyridine (10), were identified. Compounds 1-5 were purified from the ethyl acetate extract of the leaves, while 6-9 and 10 were from the ethyl acetate and ethanol extracts of the stems, respectively. Among these isolates, 10 showed the strongest antibacterial activities against S. mutans and Streptococcus mitis, with minimum inhibitory concentrations (MICs) of 2-4 μg/mL, and MLC of 4 μg/mL, as well as having a weak antifungal activity against C. albicans (MIC of 125 μg/mL). This is the first report of the antimicrobial activities of 10.

Susceptibilities of Mycoplasma fermentans and Mycoplasma hyorhinis to Membrane-Active Peptides and Enrofloxacin in Human Tissue Cell Cultures

PubMed Central

Nir-Paz, Ran; Prévost, Marie-Christine; Nicolas, Pierre; Blanchard, Alain; Wróblewski, Henri

2002-01-01

Mycoplasmas, which are bacteria that are devoid of a cell wall and which belong to the class Mollicutes, are pathogenic for humans and animals and are frequent contaminants of tissue cell cultures. Although contamination of cultures with mycoplasma can easily be monitored with fluorescent dyes that stain DNA and/or with molecular probes, protection and decontamination of cultures remain serious challenges. In the present work, we investigated the susceptibilities of Mycoplasma fermentans and Mycoplasma hyorhinis to the membrane-active peptides alamethicin, dermaseptin B2, gramicidin S, and surfactin by growth inhibition and lethality assays. In the absence of serum, the four peptides killed mycoplasmas at minimal bactericidal concentrations that ranged from 12.5 to 100 μM, but in all cases the activities were decreased by the presence of serum. As a result, under standard culture conditions (10% serum) only alamethicin and gramicidin S were able to inhibit mycoplasma growth (MICs, 50 μM), while dermaseptin B2 and surfactin were ineffective. Furthermore, 8 days of treatment of HeLa cell cultures experimentally contaminated with either mycoplasma species with 70 μM enrofloxacin cured the cultures of infection, whereas treatment with alamethicin and gramicidin S alone was not reliable because the concentrations and treatment times required were toxic to the cells. However, combination of alamethicin or gramicidin S with 70 μM enrofloxacin allowed mycoplasma eradication after 30 min or 24 h of treatment, depending on the mycoplasma and peptide considered. HeLa cell cultures experimentally infected with mycoplasmas should prove to be a useful model for study of the antimycoplasma activities of antibiotics and membrane-active peptides under conditions close to those found in vivo. PMID:11959548

Evaluation of risk assessment guideline levels for the chemical warfare agents mustard, GB, and VX.

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

Hartmann, H.; Environmental Assessment

2002-06-01

The U.S. Army has estimated acute lethality guideline levels for inhalation of the chemical warfare agents mustard, GB, and VX. These levels are expressed as dosages measured in milligram-minutes per cubic meter (mg-min/m3). The National Advisory Council has also proposed acute emergency guideline levels (AEGLs) for the agents. The AEGLs are threshold exposure limits for the general public for mild effects, serious adverse effects, and lethality. They are expressed as air concentrations (in units of mg/m3) and are applicable to emergency exposure periods ranging from 10 min to 8 h. The report discusses strengths and deficiencies in the levels, importantmore » parameters (i.e., exposure time, breathing rate) that need to be explicitly addressed in deriving the guideline levels, and possible impacts that could result from using AEGLs instead of guideline dosages in future assessments.« less

Pesticide risk assessment in free-ranging bees is weather and landscape dependent.

PubMed

Henry, Mickaël; Bertrand, Colette; Le Féon, Violette; Requier, Fabrice; Odoux, Jean-François; Aupinel, Pierrick; Bretagnolle, Vincent; Decourtye, Axel

2014-07-10

The risk assessment of plant protection products on pollinators is currently based on the evaluation of lethal doses through repeatable lethal toxicity laboratory trials. Recent advances in honeybee toxicology have, however, raised interest on assessing sublethal effects in free-ranging individuals. Here, we show that the sublethal effects of a neonicotinoid pesticide are modified in magnitude by environmental interactions specific to the landscape and time of exposure events. Field sublethal assessment is therefore context dependent and should be addressed in a temporally and spatially explicit way, especially regarding weather and landscape physiognomy. We further develop an analytical Effective Dose (ED) framework to help disentangle context-induced from treatment-induced effects and thus to alleviate uncertainty in field studies. Although the ED framework involves trials at concentrations above the expected field exposure levels, it allows to explicitly delineating the climatic and landscape contexts that should be targeted for in-depth higher tier risk assessment.

Lethal effect of dehydroleucodine (DhL) on amphibian Bufo arenarum embryos.

PubMed

Moreno, Liliana Elizabeth; Juárez, Américo Osvaldo; Pelzer, Lilian Eugenia

2012-03-01

The dehydroleucodine is a sesquiterpene lactone isolated from Artemisia douglasiana Besser which is used in popular medicine. Toxicity tests using embryos of amphibian have been widely used in order to predict toxic effects of different compounds. However, to our knowledge, there are not studies focussed on the toxic effects of dehydroleucodine on Bufo arenarum, which is an anuran widely distributed in South America. The effect of dehydroleucodine on the survival of embryos was evaluated in an acute test during the early life stage of B. arenarum embryos. Lethality and the degree of adverse effects were dehydroleucodine dose-dependent. Overall, amphibian early life stages appeared to be more susceptible to the embryotoxicity associated with exposure to dehydroleucodine, especially at concentration greater that 3mM. This increased susceptibility may result from the relatively high rate of cellular differentiation and morphogenesis that occurs at this early stage of development. Copyright © 2012 Elsevier Ltd. All rights reserved.

Fentanyl novel derivative-related deaths.

PubMed

Giorgetti, Arianna; Centola, Carmela; Giorgetti, Raffaele

2017-05-01

Fentanyl (FEN) is a potent, synthetic narcotic used as an anaesthetic and a pain reliever, but also illegally manufactured. For diversion purpose, it is being steadily modified to produce new analogous compounds and derivatives (FENS), categorised as novel psychoactive substances. While potential FEN abuse is already known, even in the absence of a clear lethal dosage, there is still a shortage of data on its derivatives. A literature review of FENS-related deaths was performed, to better understand potential damage and future perspectives of FEN congeners. Epidemiological data, pathological findings, administration routes, average concentrations and lethal doses, toxicological issues, trends in misuses, comparison among FENS, and possible explanation for FENS abuse are reviewed and discussed in depth. This study provides a medical-legal and toxicological assessment of this phenomenon in order to understand the role of illegal fentanyl and its congeners in deaths from FENS overdose. Copyright © 2017 John Wiley & Sons, Ltd.

The staphylococcal enterotoxin (SE) family: SEB and siblings.

PubMed

Krakauer, Teresa; Stiles, Bradley G

2013-11-15

Staphylococcus aureus plays an important role in numerous human cases of food poisoning, soft tissue, and bone infections, as well as potentially lethal toxic shock. This common bacterium synthesizes various virulence factors that include staphylococcal enterotoxins (SEs). These protein toxins bind directly to major histocompatibility complex class II on antigen-presenting cells and specific Vβ regions of T-cell receptors, resulting in potentially life-threatening stimulation of the immune system. Picomolar concentrations of SEs ultimately elicit proinflammatory cytokines that can induce fever, hypotension, multi-organ failure, and lethal shock. Various in vitro and in vivo models have provided important tools for studying the biological effects of, as well as potential vaccines/therapeutics against, the SEs. This review succinctly presents known physical and biological properties of the SEs, including various intervention strategies. In particular, SEB will often be portrayed as per biodefense concerns dating back to the 1960s.

Toxicity of Imidacloprid to the Stingless Bee Scaptotrigona postica Latreille, 1807 (Hymenoptera: Apidae).

PubMed

Soares, Hellen Maria; Jacob, Cynthia Renata Oliveira; Carvalho, Stephan Malfitano; Nocelli, Roberta Cornélio Ferreira; Malaspina, Osmar

2015-06-01

The stingless bee Scaptotrigona postica is an important pollinator of native and cultivated plants in Brazil. Among the factors affecting the survival of these insects is the indiscriminate use of insecticides, including the neonicotinoid imidacloprid. This work determined the toxicity of imidacloprid as the topical median lethal dose (LD50) and the oral median lethal concentration (LC50) as tools for assessing the effects of this insecticide. The 24 and 48 h LD50 values were 25.2 and 24.5 ng of active ingredient (a.i.)/bee, respectively. The 24 and 48 h LC50 values were 42.5 and 14.3 ng a.i./µL of diet, respectively. Ours results show the hazard of imidacloprid and the vulnerability of stingless bees to it, providing relevant toxicological data that can used in mitigation programs to ensure the conservation of this species.

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

The staphylococcal enterotoxin (SE) family

PubMed Central

Krakauer, Teresa; Stiles, Bradley G

2013-01-01

Staphylococcus aureus plays an important role in numerous human cases of food poisoning, soft tissue, and bone infections, as well as potentially lethal toxic shock. This common bacterium synthesizes various virulence factors that include staphylococcal enterotoxins (SEs). These protein toxins bind directly to major histocompatibility complex class II on antigen-presenting cells and specific Vβ regions of T-cell receptors, resulting in potentially life-threatening stimulation of the immune system. Picomolar concentrations of SEs ultimately elicit proinflammatory cytokines that can induce fever, hypotension, multi-organ failure, and lethal shock. Various in vitro and in vivo models have provided important tools for studying the biological effects of, as well as potential vaccines/therapeutics against, the SEs. This review succinctly presents known physical and biological properties of the SEs, including various intervention strategies. In particular, SEB will often be portrayed as per biodefense concerns dating back to the 1960s. PMID:23959032

In vitro study of the neuropathic potential of the organophosphorus compounds trichlorfon and acephate.

PubMed

Fernandes, Laís S; Emerick, Guilherme L; dos Santos, Neife Aparecida G; de Paula, Eloísa Silva; Barbosa, Fernando; dos Santos, Antonio Cardozo

2015-04-01

Organophosphorus-induced delayed neuropathy (OPIDN) is a central and peripheral distal axonopathy characterized by ataxia and paralysis. Trichlorfon and acephate are two organophosphorus compounds (OPs) used worldwide as insecticide and which cause serious effects to non-target species. Despite that, the neuropathic potential of these OPs remains unclear. The present study addressed the neurotoxic effects and the neuropathic potential of trichlorfon and acephate in SH-SY5Y human neuroblastoma cells, by evaluating inhibition and aging of neuropathy target esterase (NTE), inhibition of acetylcholinesterase (AChE), neurite outgrowth, cytotoxicity and intracellular calcium. Additionally, the effects observed were compared to those of two well-studied OPs: mipafox (known as neuropathic) and paraoxon (known as non-neuropathic). Trichlorfon and mipafox presented the lowest percentage of reactivation of inhibited NTE and the lowest ratio IC50 NTE/IC50 AChE. Moreover, they caused inhibition and aging of at least 70% of the activity of NTE at sub-lethal concentrations. All these effects have been associated with induction of OPIDN. When assayed at these concentrations, trichlorfon and mipafox reduced neurite outgrowth and increased intracellular calcium, events implicated in the development of OPIDN. Acephate caused effects similar to those caused by paraoxon (non-neuropathic OP) and was only able to inhibit 70% of NTE activity at lethal concentrations. These findings suggest that trichlorfon is potentially neuropathic, whereas acephate is not. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of Bromouracil-containing Deoxyribonucleic Acid on Bacillus subtilis

PubMed Central

Gimlin, Dixie M.; Hardman, Sue D.; Kelley, Betty N.; Butler, Grace C.; Leach, Franklin R.

1966-01-01

Gimlin, Dixie M. (Oklahoma State University, Stillwater), Sue D. Hardman, Betty N. Kelley, Grace C. Butler, and Franklin R. Leach. Effect of bromouracil-containing deoxyribonucleic acid on Bacillus subtilis. J. Bacteriol. 92:366–374. 1966.—Replacement of one-half of the thymine with bromouracil in Bacillus subtilis transforming deoxyribonucleic acid (DNA) resulted in a slight decrease in transforming activity, but, when used at high concentrations, this DNA preparation inhibited cell growth. Acid-hydrolyzed DNA, or addition of equivalent concentrations of the free base bromouracil in a transforming mixture, was without effect on cell growth. Treatment of the DNA preparation with deoxyribonuclease completely destroyed transforming activity and killing effect, whereas treatments with ribonuclease and trypsin were without effect on either transformation or killing activity. Growth of competent B. subtilis cells in test tubes was inhibited by high concentrations of both normal and bromouracil-containing DNA, with the bromouracil-containing DNA being significantly more inhibitory. This type of inhibition was also reflected in the time of division of the cells. The inhibitory effect was not due to viscosity, or to mutagenicity. The time course of killing paralleled transformation, and competency was required. These results can be interpreted as being due to uptake of homologous but imperfect DNA (containing bromouracil instead of thymine) by means of the systems involved in transformation, followed by either integration (resulting in lethal transformation, activation of a defective, nonlytic but lethal prophage) or interference with the recombination mechanism. PMID:16562122

Biodiversity of soil bacteria exposed to sub-lethal concentrations of phosphonium-based ionic liquids: Effects of toxicity and biodegradation.

PubMed

Sydow, Mateusz; Owsianiak, Mikołaj; Framski, Grzegorz; Woźniak-Karczewska, Marta; Piotrowska-Cyplik, Agnieszka; Ławniczak, Łukasz; Szulc, Alicja; Zgoła-Grześkowiak, Agnieszka; Heipieper, Hermann J; Chrzanowski, Łukasz

2018-01-01

Little is known about the effect of ionic liquids (ILs) on the structure of soil microbial communities and resulting biodiversity. Therefore, we studied the influence of six trihexyl(tetradecyl)phosphonium ILs (with either bromide or various organic anions) at sublethal concentrations on the structure of microbial community present in an urban park soil in 100-day microcosm experiments. The biodiversity decreased in all samples (Shannon's index decreased from 1.75 down to 0.74 and OTU's number decreased from 1399 down to 965) with the largest decrease observed in the microcosms spiked with ILs where biodegradation extent was higher than 80%. (i.e. [P 66614 ][Br] and [P 66614 ][2,4,4]). Despite this general decrease in biodiversity, which can be explained by ecotoxic effect of the ILs, the microbial community in the microcosms was enriched with Gram-negative hydrocarbon-degrading genera e.g. Sphingomonas. It is hypothesized that, in addition to toxicity, the observed decrease in biodiversity and change in the microbial community structure may be explained by the primary biodegradation of the ILs or their metabolites by the mentioned genera, which outcompeted other microorganisms unable to degrade ILs or their metabolites. Thus, the introduction of phosphonium-based ILs into soils at sub-lethal concentrations may result not only in a decrease in biodiversity due to toxic effects, but also in enrichment with ILs-degrading bacteria. Copyright © 2017 Elsevier Inc. All rights reserved.

Lethal and Sublethal Effects of the Herbicide Atrazine in the Early Stages of Development of Physalaemus gracilis (Anura: Leptodactylidae).

PubMed

Rutkoski, Camila F; Macagnan, Natani; Kolcenti, Cassiane; Vanzetto, Guilherme V; Sturza, Paola F; Hartmann, Paulo A; Hartmann, Marilia T

2018-05-01

Water sources used as reproductive sites by crying frog, Physalaemus gracilis, are extensively associated with agroecosystems in which the herbicide atrazine is employed. To evaluate the lethal and sublethal effects of atrazine commercial formulation, acute and chronic toxicity tests were performed in the embryonic phase and the beginning of the larval phase of P. gracilis. Tests were started on stage 19 of Gosner (Herpetologica 16:183-190, 1960) and performed in 24-well cell culture plates. Acute tests had a duration of 96 h with embryo mortality monitoring every 24 h. Chronic assays contemplated the transition from the embryonic to larval stages and lasted 168 h. Every 24 h the embryos/larvae were observed for mortality, mobility, and malformations. The LC50 of atrazine determined for P. gracilis embryos was 229.34 mg L -1 . The sublethal concentrations did not affect the development of the larvae but were observed effects on mobility and malformations, such as spasmodic contractions, reduced mobility, malformations in mouth and intestine, and edema arising. From 1 mg L -1 atrazine, the exposed larvae began to have changes in mobility and malformations. The atrazine commercial formulation has caused early life effects of P. gracilis that may compromise the survival of this species but at higher concentrations than recorded in the environment, so P. gracilis can be considered tolerant to this herbicide at environmentally relevant concentrations.

The Antibacterial Activity of Date Syrup Polyphenols against S. aureus and E. coli

PubMed Central

Taleb, Hajer; Maddocks, Sarah E.; Morris, R. Keith; Kanekanian, Ara D.

2016-01-01

Plant-derived products such as date syrup (DS) have demonstrated antibacterial activity and can inhibit bacteria through numerous different mechanisms, which may be attributed to bioactive compounds including plant-derived phenolic molecules. DS is rich in polyphenols and this study hypothesized that DS polyphenols demonstrate inherent antimicrobial activity, which cause oxidative damage. This investigation revealed that DS has a high content of total polyphenols (605 mg/100 g), and is rich in tannins (357 mg/100 g), flavonoids (40.5 mg/100 g), and flavanols (31.7 mg/100 g) that are known potent antioxidants. Furthermore, DS, and polyphenols extracted from DS, the most abundant bioactive constituent of DS are bacteriostatic to both Gram positive and Gram negative Escherichia coli and Staphylococcus aureus, respectively. It has further been shown that the extracted polyphenols independently suppress the growth of bacteria at minimum inhibitory concentration (MIC) of 30 and 20 mg/mL for E. coli and S. aureus, and have observed that DS behaves as a prooxidant by generating hydrogen peroxide that mediates bacterial growth inhibition as a result of oxidative stress. At sub-lethal MIC concentrations DS demonstrated antioxidative activity by reducing hydrogen peroxide, and at lethal concentrations DS demonstrated prooxidant activity that inhibited the growth of E. coli and S. aureus. The high sugar content naturally present in DS did not significantly contribute to this effect. These findings highlight that DS’s antimicrobial activity is mediated through hydrogen peroxide generation in inducing oxidative stress in bacteria. PMID:26952177

Acridine orange staining reaction as an index of physiological activity in Escherichia coli

NASA Technical Reports Server (NTRS)

McFeters, G. A.; Singh, A.; Byun, S.; Callis, P. R.; Williams, S.

1991-01-01

The assumption that the acridine orange (AO) color reaction may be used as an index of physiological activity was investigated in laboratory grown Escherichia coli. Spectrofluorometric observations of purified nucleic acids, ribosomes and the microscopic color of bacteriophage-infected cells stained with AO confirmed the theory that single-stranded nucleic acids emit orange to red fluorescence while those that are double-stranded fluoresce green in vivo. Bacteria growing actively in a rich medium could be distinguished from cells in stationary phase by the AO reaction. Cells from log phase appeared red, whereas those in stationary phase were green. However, this differentiation was not seen when the bacteria were grown in a minimal medium or when a variation of the staining method was used. Also, shifting bacteria in stationary phase to starvation conditions rapidly changed their AO staining reaction. Boiling and exposure to lethal concentrations of azide and formalin resulted in stationary-phase cells that appeared red after staining but bacteria killed with chlorine remained green. These findings indicate that the AO staining reaction may be suggestive of physiological activity under defined conditions. However, variables in staining and fixation procedures as well as uncertainties associated with mixed bacterial populations in environmental samples may produce results that are not consistent with the classical interpretation of this reaction. The importance of validating the putative physiological implications of this staining reaction is stressed.

Separating the attractant from the toxicant improves attract-and-kill of codling moth (Lepidoptera: Tortricidae).

PubMed

Huang, Juan; Gut, Larry J; Miller, James R

2013-10-01

The behavior of codling moth, Cydia pomonella (L.), responding to three attract-and-kill devices was compared in flight tunnel experiments measuring attraction and duration of target contact. Placing a 7.6 by 12.6 cm card immediately upwind of a rubber septum releasing pheromone, dramatically increased the duration on the target to > 60 s. In this setting, nearly all the males flew upwind, landed on the card first, and spent the majority of time searching the card. In contrast, male codling moths spent < 15 s at the source if given the lure only. In a forced contact bioassay, knockdown rate or mortality of male codling moths increased in direct proportion to duration of contact on a lambda-cyhalothrin-loaded filter paper. When this insecticide-treated paper was placed immediately upwind of the lure in the flight tunnel, > 90% of males contacting the paper were knocked down 2 h after voluntary exposure. These findings suggest that past attempts to combine insecticide directly with sex pheromones into a small paste, gel, or other forms of dollops are ill-advised because moths are likely over-exposed to pheromone and vacate the target before obtaining a lethal dose of insecticide. It is better to minimize direct contact with the concentrated pheromone while enticing males to extensively search insecticide-treated surface nearby the lure.

A non-human primate model of human radiation-induced venocclusive liver disease and hepatocyte injury

PubMed Central

Yamamoto, Toshiyuki; Ito, Ryotaro; Brooks, Jenna M.; Guzman-Lepe, Jorge; Galambos, Csaba; Fong, Jason V.; Deutsch, Melvin; Quader, Mubina A.; Yamanouchi, Kosho; Kabarriti, Rafi; Mehta, Keyur; Soto-Gutierrez, Alejandro; Roy-Chowdhury, Jayanta; Locker, Joseph; Abe, Michio; Enke, Charles A.; Baranowska-Kortylewicz, Janina; Solberg, Timothy D.; Guha, Chandan; Fox, Ira J.

2014-01-01

Background Human liver has an unusual sensitivity to radiation that limits its use in cancer therapy or in preconditioning for hepatocyte transplantation. Since the characteristic venocclusive lesions of radiation-induced liver disease do not occur in rodents, there has been no experimental model to investigate the limits of safe radiation therapy or explore the pathogenesis of hepatic venocclusive disease. Methods We performed a dose escalation study in a primate, the cynomolgus monkey, using hypofractionated stereotactic body radiotherapy in 13 animals. Results At doses ≥40Gy, animals developed a systemic syndrome resembling human radiation-induced liver disease, consisting of decreased albumin, elevated alkaline phosphatase, loss of appetite, ascites, and normal bilirubin. Higher radiation doses were lethal, causing severe disease that required euthanasia approximately 10 weeks after radiation. Even at lower doses where radiation-induced liver disease was mild or non-existent, latent and significant injury to hepatocytes was demonstrated by asialoglycoprotein-mediated functional imaging. These monkeys developed hepatic failure with encephalopathy when they received parenteral nutrition containing high concentrations of glucose. Histologically, livers showed central obstruction via an unusual intimal swelling that progressed to central fibrosis. Conclusions The cynomolgus monkey, as the first animal model of human venocclusive radiation-induced liver disease, provides a resource for characterizing the early changes and pathogenesis of venocclusion, for establishing nonlethal therapeutic dosages, and for examining experimental therapies to minimize radiation injury. PMID:24315566

MinGenome: An In Silico Top-Down Approach for the Synthesis of Minimized Genomes.

PubMed

Wang, Lin; Maranas, Costas D

2018-02-16

Genome minimized strains offer advantages as production chassis by reducing transcriptional cost, eliminating competing functions and limiting unwanted regulatory interactions. Existing approaches for identifying stretches of DNA to remove are largely ad hoc based on information on presumably dispensable regions through experimentally determined nonessential genes and comparative genomics. Here we introduce a versatile genome reduction algorithm MinGenome that implements a mixed-integer linear programming (MILP) algorithm to identify in size descending order all dispensable contiguous sequences without affecting the organism's growth or other desirable traits. Known essential genes or genes that cause significant fitness or performance loss can be flagged and their deletion can be prohibited. MinGenome also preserves needed transcription factors and promoter regions ensuring that retained genes will be properly transcribed while also avoiding the simultaneous deletion of synthetic lethal pairs. The potential benefit of removing even larger contiguous stretches of DNA if only one or two essential genes (to be reinserted elsewhere) are within the deleted sequence is explored. We applied the algorithm to design a minimized E. coli strain and found that we were able to recapitulate the long deletions identified in previous experimental studies and discover alternative combinations of deletions that have not yet been explored in vivo.

Protective effects of S+ ketamine and atropine against lethality and brain damage during soman-induced status epilepticus in guinea-pigs.

PubMed

Dorandeu, Frederic; Baille, Valerie; Mikler, John; Testylier, Guy; Lallement, Guy; Sawyer, Thomas; Carpentier, Pierre

2007-05-20

Soman poisoning is known to induce full-blown tonic-clonic seizures, status epilepticus (SE), seizure-related brain damage (SRBD) and lethality. Previous studies in guinea-pigs have shown that racemic ketamine (KET), with atropine sulfate (AS), is very effective in preventing death, stopping seizures and protecting sensitive brain areas when given up to 1h after a supra-lethal challenge of soman. The active ketamine isomer, S(+) ketamine (S-KET), is more potent than the racemic mixture and it also induces less side-effects. To confirm the efficacy of KET and to evaluate the potential of S-KET for delayed medical treatment of soman-induced SE, we studied different S-KET dose regimens using the same paradigm used with KET. Guinea-pigs received pyridostigmine (26 microg/kg, IM) 30min before soman (62 microg/kg, 2 LD(50), IM), followed by therapy consisting of atropine methyl nitrate (AMN) (4 mg/kg, IM) 1min following soman exposure. S-KET, with AS (10mg/kg), was then administered IM at different times after the onset of seizures, starting at 1h post-soman exposure. The protective efficacy of S-KET proved to be comparable to KET against lethality and SRBD, but at doses two to three times lower. As with KET, delaying treatment by 2h post-poisoning greatly reduced efficacy. Conditions that may have led to an increased S-KET brain concentration (increased doses or number of injections, adjunct treatment with the oxime HI-6) did not prove to be beneficial. In summary, these observations confirm that ketamine, either racemic or S-KET, in association with AS and possibly other drugs, could be highly effective in the delayed treatment of severe soman intoxication.

Synthesis of silver and gold nanoparticles using Jasminum nervosum leaf extract and its larvicidal activity against filarial and arboviral vector Culex quinquefasciatus Say (Diptera: Culicidae).

PubMed

Lallawmawma, H; Sathishkumar, Gnanasekar; Sarathbabu, Subburayan; Ghatak, Souvik; Sivaramakrishnan, Sivaperumal; Gurusubramanian, Guruswami; Kumar, Nachimuthu Senthil

2015-11-01

Silver and gold nanoparticles of Jasminum nervosum L. had unique optical properties such as broad absorbance band in the visible region of the electromagnetic spectrum. Characterization of the nanoparticles using UV spectrophotometer, Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy confirmed that the particles were silver (AgNPs) and gold (AuNPs) ranging between 4-22 and 2-20 nm with an average particles size of 9.4 and 10 nm, respectively. AgNPs and AuNPs of J. nervosum had high larvicidal activity on the filarial and arboviral vector, Culex quinquefasciatus, than the leaf aqueous extract. Observed lethal concentrations (LC50 and LC95) against the third instar larvae were 57.40 and 144.36 μg/ml for AgNPs and 82.62 and 254.68 μg/ml for AuNPs after 24 h treatment, respectively. The lethal time to kill 50% of C. quinquefasciatus larvae were 2.24 and 4.51 h at 150 μg/ml of AgNPs and AuNPs, respectively, while in the case of aqueous leaf extract of J. nervosum it was 9.44 h at 500 μg/ml (F 2,14 = 397.51, P < 0.0001). The principal component analysis plot presented differential clustering of the aqueous leaf extract, AgNP and AuNPs in relation to lethal dose and lethal time. It is concluded from the present findings that the biosynthesised AgNPs and AuNPs using leaf aqueous extract of J. nervosum could be an environmentally safer nanobiopesticide, and provided potential larvicidal effect on C. quinquefasciatus larvae which could be used for prevention of several dreadful diseases.

Prophylaxis with human serum butyrylcholinesterase protects Göttingen minipigs exposed to a lethal high-dose of sarin vapor.

PubMed

Saxena, Ashima; Hastings, Nicholas B; Sun, Wei; Dabisch, Paul A; Hulet, Stanley W; Jakubowski, Edward M; Mioduszewski, Robert J; Doctor, Bhupendra P

2015-08-05

Serum-derived human butyrylcholinesterase (Hu BChE) is a stoichiometric bioscavenger that is being developed as a potential prophylactic nerve agent countermeasure. Previously, we reported the prophylactic efficacy of Hu BChE in Göttingen minipigs against a whole-body exposure to 4.1mg/m(3) of sarin (GB) vapor, which produced lethality over 60min. Since the toxicity of nerve agent is concentration-dependent, in the present study, we investigated the toxic effects of an almost 3-fold higher rate of GB vapor exposure and the ability of Hu BChE to protect minipigs against this exposure. Male minipigs were subjected to: (1) air exposure; (2) GB vapor exposure; or (3) pretreatment with 7.5mg/kg of Hu BChE by i.m. injection, 24h prior to whole-body exposure to 11.4mg/m(3) of GB vapor for 10min. Electrocardiogram, electroencephalogram, and pupil size were monitored throughout exposure. Blood drawn before and throughout exposure was analyzed for blood gases, electrolytes, metabolites, acetylcholinesterase and BChE activities, and amount of GB bound to red blood cells and plasma. A novel finding was that saline-treated animals exposed to GB vapor did not develop any seizures, but manifested a variety of cardiac and whole blood toxic signs and rapidly died due to respiratory failure. Strikingly, pre-treatment with 7.5mg/kg of Hu BChE not only prevented lethality, but also avoided all cardiac toxic signs manifested in the non-treated cohort. Thus, Hu BChE alone can serve as an effective prophylactic countermeasure versus a lethal high-dose exposure to GB vapor. Published by Elsevier Ireland Ltd.

From blood to breath: New horizons for esophageal cancer biomarkers.

PubMed

Yazbeck, Roger; Jaenisch, Simone E; Watson, David I

2016-12-14

Esophageal cancer is a lethal cancer encompassing adenocarcinoma and squamous cell carcinoma sub-types. The global incidence of esophageal cancer is increasing world-wide, associated with the increased prevalence of associated risk factors. The asymptomatic nature of disease often leads to late diagnosis and five-year survival rates of less than 15%. Current diagnostic tools are restricted to invasive and costly endoscopy and biopsy for histopathology. Minimally and non-invasive biomarkers of esophageal cancer are needed to facilitate earlier detection and better clinical management of patients. This paper summarises recent insights into the development and clinical validation of esophageal cancer biomarkers, focussing on circulating markers in the blood, and the emerging area of breath and odorant biomarkers.

Immune Protection against Lethal Fungal-Bacterial Intra-Abdominal Infections.

PubMed

Lilly, Elizabeth A; Ikeh, Melanie; Nash, Evelyn E; Fidel, Paul L; Noverr, Mairi C

2018-01-16

Polymicrobial intra-abdominal infections (IAIs) are clinically prevalent and cause significant morbidity and mortality, especially those involving fungi. Our laboratory developed a mouse model of IAI and demonstrated that intraperitoneal inoculation with Candida albicans or other virulent non- albicans Candida (NAC) species plus Staphylococcus aureus resulted in 70 to 80% mortality in 48 to 72 h due to robust local and systemic inflammation (sepsis). Surprisingly, inoculation with Candida dubliniensis or Candida glabrata with S. aureus resulted in minimal mortality, and rechallenge of these mice with lethal C. albicans / S. aureus (i.e., coninfection) resulted in >90% protection. The purpose of this study was to define requirements for C. dubliniensis / S. aureus -mediated protection and interrogate the mechanism of the protective response. Protection was conferred by C. dubliniensis alone or by killed C. dubliniensis plus live S. aureus S. aureus alone was not protective, and killed S. aureus compromised C. dubliniensis -induced protection. C. dubliniensis / S. aureus also protected against lethal challenge by NAC plus S. aureus and could protect for a long-term duration (60 days between primary challenge and C. albicans/S. aureus rechallenge). Unexpectedly, mice deficient in T and B cells (Rag-1 knockouts [KO]) survived both the initial C. dubliniensis/S. aureus challenge and the C. albicans/S. aureus rechallenge, indicating that adaptive immunity did not play a role. Similarly, mice depleted of macrophages prior to rechallenge were also protected. In contrast, protection was associated with high numbers of Gr-1 hi polymorphonuclear leukocytes (PMNLs) in peritoneal lavage fluid within 4 h of rechallenge, and in vivo depletion of Gr-1 + cells prior to rechallenge abrogated protection. These results suggest that Candida species can induce protection against a lethal C. albicans / S. aureus IAI that is mediated by PMNLs and postulated to be a unique form of trained innate immunity. IMPORTANCE Polymicrobial intra-abdominal infections are clinically devastating infections with high mortality rates, particularly those involving fungal pathogens, including Candida species. Even in patients receiving aggressive antimicrobial therapy, mortality rates remain unacceptably high. There are no available vaccines against IAI, which is complicated by the polymicrobial nature of the infection. IAI leads to lethal systemic inflammation (sepsis), which is difficult to target pharmacologically, as components of the inflammatory response are also needed to control the infection. Our studies demonstrate that prior inoculation with low-virulence Candida species provides strong protection against subsequent lethal infection with C. albicans and S. aureus Surprisingly, protection is long-lived but not mediated by adaptive (specific) immunity. Instead, protection is dependent on cells of the innate immune system (nonspecific immunity) and provides protection against other virulent Candida species. This discovery implies that a form of trained innate immunity may be clinically effective against polymicrobial IAI. Copyright © 2018 Lilly et al.

Comparative sensitivity of the cnidarian Exaiptasia pallida and a standard toxicity test suite: testing whole effluents intended for ocean disposal.

PubMed

Howe, P L; Reichelt-Brushett, A J; Krassoi, R; Micevska, T

2015-09-01

The sea anemone Exaiptasia pallida (formally Aiptasia pulchella) has been identified as a valuable test species for tropical marine ecotoxicology. Here, the sensitivities of newly developed endpoints for E. pallida to two unidentified whole effluents were compared to a standard suite of temperate toxicity test species and endpoints that are commonly used in toxicological risk assessments for tropical marine environments. For whole effluent 1 (WE1), a 96-h lethal concentration 50 % (LC50) of 40 (95 % confidence intervals, 30-54) % v/v and a 12-day LC50 of 12 (9-15) % v/v were estimated for E. pallida, exhibiting a significantly higher sensitivity than standard sub-lethal endpoints in Allorchestes compressa (96-h effective concentration 50 % (EC50) of >100 % v/v for immobilisation) and Hormosira banksii (72-h EC50 of >100 % v/v for germination), and a similar sensitivity to Mytilus edulis galloprovincialis larval development with a 48-h LC50 of 29 (28-30) % v/v. Sub-lethal effects of whole effluent 2 (WE2) on E. pallida pedal lacerate development resulted in an 8-day EC50 of 7 (3-11) % v/v, demonstrating comparable sensitivity of this endpoint to standardised sub-lethal endpoints in H. banksii (72-h EC50 of 11 (10-11) % v/v for germination), M. edulis galloprovincialis (48-h EC50 for larval development of 12 (9-14) % v/v) and Heliocidaris tuberculata (1-h EC50 of 13 (12-14) % v/v for fertilisation; 72-h EC50 of 26 (25-27) % v/v for larval development) and a significantly higher sensitivity than A. compressa immobilisation (96-h EC50 of >100 % v/v). The sensitivity of E. pallida compared to a standard test species suite highlights the value in standardising the newly developed toxicity test methods for inclusion in routine toxicological risk assessment of complex whole effluents. Importantly, this species provides an additional taxonomic group to the test species that are currently available for tropical marine ecotoxicology and, being a cnidarian, may represent important tropical marine environments including coral reefs.

Synergistic effect of piperonyl butoxide on acute toxicity of pyrethrins to Hyalella azteca.

PubMed

Giddings, Jeffrey; Gagne, James; Sharp, Janice

2016-08-01

A series of acute toxicity tests with the amphipod Hyalella azteca was performed to quantify the synergistic effect of piperonyl butoxide (PBO) on pyrethrin toxicity. Concentrations of PBO <4 µg/L caused no toxicity enhancement, whereas toxicity increased with PBO concentrations between 4 µg/L and 15 µg/L. Additive toxicity calculations showed that true synergism accounted for an increase in pyrethrin toxicity (decrease in median lethal concentration) of 1.4-fold to 1.6-fold and varied only slightly between 4 µg/L and 15 µg/L PBO, whereas direct toxicity of PBO accounted for an additional increase in mixture toxicity (up to 3.2-fold) that was proportional to PBO concentration. The results can be used to assess the risk of measured or predicted co-occurring concentrations of PBO and pyrethrins in surface waters. Environ Toxicol Chem 2016;35:2111-2116. © 2016 SETAC. © 2016 SETAC.

The Natural Antimicrobial Carvacrol Inhibits Quorum Sensing in Chromobacterium violaceum and Reduces Bacterial Biofilm Formation at Sub-Lethal Concentrations

PubMed Central

Burt, Sara A.; Ojo-Fakunle, Victoria T. A.; Woertman, Jenifer; Veldhuizen, Edwin J. A.

2014-01-01

The formation of biofilm by bacteria confers resistance to biocides and presents problems in medical and veterinary clinical settings. Here we report the effect of carvacrol, one of the major antimicrobial components of oregano oil, on the formation of biofilms and its activity on existing biofilms. Assays were carried out in polystyrene microplates to observe (a) the effect of 0–0.8 mM carvacrol on the formation of biofilms by selected bacterial pathogens over 24 h and (b) the effect of 0–8 mM carvacrol on the stability of pre-formed biofilms. Carvacrol was able to inhibit the formation of biofilms of Chromobacterium violaceum ATCC 12472, Salmonella enterica subsp. Typhimurium DT104, and Staphylococcus aureus 0074, while it showed no effect on formation of Pseudomonas aeruginosa (field isolate) biofilms. This inhibitory effect of carvacrol was observed at sub-lethal concentrations (<0.5 mM) where no effect was seen on total bacterial numbers, indicating that carvacrol's bactericidal effect was not causing the observed inhibition of biofilm formation. In contrast, carvacrol had (up to 8 mM) very little or no activity against existing biofilms of the bacteria described, showing that formation of the biofilm also confers protection against this compound. Since quorum sensing is an essential part of biofilm formation, the effect of carvacrol on quorum sensing of C. violaceum was also studied. Sub-MIC concentrations of carvacrol reduced expression of cviI (a gene coding for the N-acyl-L-homoserine lactone synthase), production of violacein (pigmentation) and chitinase activity (both regulated by quorum sensing) at concentrations coinciding with carvacrol's inhibiting effect on biofilm formation. These results indicate that carvacrol's activity in inhibition of biofilm formation may be related to the disruption of quorum sensing. PMID:24691035

Application of a unique test design to determine the chronic toxicity of boron to the aquatic worm Lumbriculus variegatus and fatmucket mussel Lampsilis siliquoidea.

PubMed

Hall, Scott; Lockwood, Rick; Harrass, Michael C

2014-01-01

The chronic (21- and 28-day) toxicity of boron was determined for two freshwater benthic macroinvertebrates: the fatmucket mussel Lampsilis siliquoidea and the aquatic worm Lumbriculus variegatus. The rapid depletion of boric acid from spiked sediments in tests using flow-through overlying waters was addressed by constant addition of boric acid to overlying water at concentrations matching those of the targeted porewater exposures. This proved highly successful in maintaining constant whole-sediment and sediment porewater boron concentrations. Boron sublethal 25 % inhibition concentration values based on porewater concentrations were 25.9 mg B/L (L. variegatus) and 38.5 mg B/L (L. siliquoidea), indicating similar test organism sensitivity. Expressed as dry whole-sediment values, the respective L. variegatus and L. siliquoidea sublethal (growth) IC25 values for whole-sediment exposures were 235.5 mg B/kg sediment dry weight (dw) and 310.6 mg B/kg dw. The worm lethality-based end points indicated greater sensitivity than the sublethal end points, bringing into question the validity of a "lethality" end point for L. variegatus given its fragmentation mode of reproduction. For comparison, water-only mussel exposures were tested resulting in an IC25 value of 34.6 mg B/L, which was within 20 % of the porewater value. This suggests that the primary route of boron exposure was through the aqueous phase. The results of this study indicated that for test materials that are readily water soluble, standard sediment test designs may be unsuitable, but water-only exposures can provide toxicological data representative of sediment tests.

Toxicological effects on earthworms (Eisenia fetida) exposed to sub-lethal concentrations of BDE-47 and BDE-209 from a metabolic point.

PubMed

Liang, Ruoyu; Chen, Juan; Shi, Yajuan; Lu, Yonglong; Sarvajayakesavalu, Suriyanarayanan; Xu, Xiangbo; Zheng, Xiaoqi; Khan, Kifayatullah; Su, Chao

2018-05-15

Earthworms improve the soil fertility and they are also sensitive to soil contaminants. Earthworms (Eisenia fetida), standard reference species, were usually chosen to culture and handle for toxicity tests. Metabolic responses in earthworms exposed to 2, 2', 4, 4'-tetrabromodiphenyl ether (BDE-47) and decabromodiphenyl ether (BDE-209) were inhibitory and interfered with basal metabolism. In this study, 1 H-NMR based metabolomics was used to identify sensitive biomarkers and explore metabolic responses of earthworms under sub-lethal BDE-47 and BDE-209 concentrations for 14 days. The results revealed that lactate was accumulated in earthworms exposed to BDE-47 and BDE-209. Glutamate increased significantly when the concentration of BDE-47 and BDE-209 reached 10 mg/kg. The BDE-47 exposure above 50 mg/kg concentration decreased the content of fumarate significantly, which was noticed different from that of BDE-209. Whereas, the BDE-207 or BDE-209 exposure increased the protein degradation into amino acids in vivo. The increased betaine content indicated that earthworms may maintain the cell osmotic pressure and protected enzyme activity by metabolic regulation. Moreover, the BDE-47 and BDE-209 exposure at 10 mg/kg changed most of the metabolites significantly, indicating that the metabolic responses were more sensitive than growth inhibition and gene expression. The metabolomics results revealed the toxic modes of BDE-47 and BDE-209 act on the osmoregulation, energy metabolism, nerve activities, tricarboxylic acid cycle and amino acids metabolism. Furthermore, our results highlighted that the 1 H-NMR based metabolomics is a strong tool for identifying sensitive biomarkers and eco-toxicological assessment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Effects of Insecticides and Fungicides Commonly Used in Tomato Production on Phytoseiulus persimilis (Acari: Phtyoseiidae).

PubMed

Ditillo, J L; Kennedy, G G; Walgenbach, J F

2016-12-01

The twospotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is an important pest of tomatoes in North Carolina. Resident populations of the predatory mite Phytoseiulus persimilis have recently been detected on field-grown tomatoes in central North Carolina, and potentially can be a useful biological control agent against T. urticae Laboratory bioassays were used to assess lethal and reproductive effects of 10 insecticides and five fungicides commonly used in commercial tomato production (chlorantraniliprole, spinetoram, permethrin, imidacloprid, dimethoate, dinotefuran, thiamethoxam, bifenthrin, fenpropathrin, lambda-cyhalothrin, azoxystrobin, chlorothalonil, boscalid, cyazofamid, and mancozeb) on P. persimilis adult females and eggs. Insecticides were tested using concentrations equivalent to 1×, 0.5×, and 0.1× of the recommended field rates. Fungicides were tested at the 1× rate only. Dimethoate strongly impacted P. persimilis with high adult mortality, reduced fecundity, and reduced hatch of eggs laid by treated adults, particularly at high concentrations. The pyrethroids lambda-cyhalothrin, bifenthrin, and fenpropathrin were associated with repellency and reproductive effects at high concentrations. Bifenthrin additionally caused increased mortality at high concentrations. Chlorantraniliprole, dinotefuran, and permethrin did not significantly affect mortality or reproduction. Imidacloprid significantly reduced fecundity and egg viability, but was not lethal to adult P. persimilis Thiamethoxam negatively impacted fecundity at the 1× rate. There were no negative effects associated with fungicide exposure with the exception of mancozeb, which impacted fecundity. Field trials were conducted to explore the in vivo impacts of screened insecticides on P. persimilis populations in the field. Field trials supported the incompatibility of dimethoate with P. persimilis populations. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.