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Sample records for gill erod activity

  1. Joint effects of crude oil and heavy metals on the gill filament EROD activity of marbled rockfish Sebastiscus marmoratus.

    PubMed

    Zheng, Ronghui; Chen, Huanbin; Bo, Jun; Xie, Qing; Hong, Fukun; Zhang, Yusheng

    2016-10-01

    The aim of this study was to characterize dose- and time-dependent responses of gill 7-ethoxyresorufin O-deethylase (EROD) activity from Juvenile marbled rockfish (Sebastiscus marmoratus) exposed to the water-accommodated fraction (WAF) of crude oil and heavy metal Cd(Ⅱ) or Pb(Ⅱ) alone or in mixture. Compared to the control group, gill filament EROD activity in S. marmoratus was significantly induced after exposure to the WAF from 80 to 320μg/L for 5 days in dose response experiment and after exposure to 40μg/L WAF for 6-10 days in time course experiment, respectively. In the other hand, gill filament EROD activity were not significantly affected compared to the control group or related WAF groups no matter in the dose response experiment or in the time course experiment of Cd(Ⅱ), Pb(Ⅱ) or its mixture with WAF. The results suggest the use of gill filament EROD activity as a biomarker of exposure to waterborne AhR agonists in marine ecosystems while simultaneously being exposed to environmental concentrations of Cd(Ⅱ) or Pb(Ⅱ). PMID:27290642

  2. Xenobiotic and steroid biotransformation activities in rainbow trout gill epithelial cells in culture.

    PubMed

    Leguen; Carlsson; Perdu-Durand; Prunet; Pärt; Cravedi

    2000-03-01

    The biotransformation of xenobiotics and steroids was investigated in cultured respiratory epithelial cells from rainbow trout (Oncorhynchus mykiss) gills. As a first approach, ethoxyresorufin-O-deethylase (EROD), chosen as a marker of CYP1A activity, was measured in monolayers of adherent cells. The induction of this enzyme was studied in cells exposed to beta-naphthoflavone (BNF) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in concentrations ranging from 10(-6) to 10(-12) M. After 24 h, TCDD showed a maximal induction at a concentration of 10(-9) M while BNF showed a maximal induction at a concentration of 10(-7) M. Concurrently, a variety of substrates involved in cytochrome P450-dependent metabolism as well as phase II reactions, namely ethoxycoumarin, aniline and testosterone were incubated with cultured gill cells for 2 or 8 h and with freshly isolated hepatocytes for comparison. Our results revealed a significant cytochrome P450-dependent activity in gill cells with ethoxycoumarin and aniline, but no hydroxylation was observed with testosterone as substrate. No trace of sulfate conjugate was detected. With 2.5 µM aniline as substrate, 2-hydroxyaniline accounted for 32.1% of the radioactivity after 2 h incubation whereas acetanilide amounted to 6.4%. Significant differences were found between gill cells and isolated hepatocytes in the capacity of these systems to conduct oxidative and conjugating metabolic pathways. Qualitatively, the main difference was observed for testosterone which is hydroxylated in position 6beta and 16beta and conjugated to glucuronic acid in liver cells, whereas reductive biotransformation giving rise to dihydrotestosterone and androstanediol and traces of androstenedione were observed in gill cells. Quantitatively, the biotransformation activity in gill epithelial cells, expressed as pmol/h per mg protein, was between 1.5 and 14% of the activity level observed in isolated hepatocytes, depending on the substrate. PMID:10686323

  3. Study of erodable paint properties involved in antifouling activity.

    PubMed

    Thouvenin, M; Langlois, V; Briandet, R; Langlois, J Y; Guerin, P H; Peron, J J; Haras, D; Vallee-Rehel, K

    2003-06-01

    To produce ecological marine paints, it is necessary to understand the phenomena involved in antifouling activity. Due to the multivariable components which have to be taken into account and due to their analytical intricacy, only studies based on selected properties are conceivable. In this study, four properties have been chosen, viz. erosion, biocide release, roughness and the physicochemical characteristics of the film surface. A principal-component analysis (PCA) of the experimental data has shown that, among the selected properties, only erosion affected antifouling efficiency. A more detailed investigation of erosion by quantifying global hydration and hydrolysis of immersed paints revealed the difficulty in linking the chemical structure of binders to the final erosion properties. Biocide release from paints, quantified by chromatographic methods coupled with UV detection, was inferior to the doses stated by the paint producers. These observations allowed the conceiving of formulations with reduced amounts of active molecules. The development of erodable, biodegradable binders associated with non toxic compounds is a promising way to obtain efficient antifouling paints compatible with existing, preventive systems. PMID:14619286

  4. Rapid activation of gill Na+,K+-ATPase in the euryhaline teleost Fundulus heteroclitus

    USGS Publications Warehouse

    Mancera, J.M.; McCormick, S.D.

    2000-01-01

    The rapid activation of gill Na+,K+-ATPase was analyzed in the mummichog (Fundulus heteroclitus) and Atlantic salmon (Salmo salar) transferred from low salinity (0.1 ppt) to high salinity (25-35 ppt). In parr and presmolt, Salmo salar gill Na+,K+-ATPase activity started to increase 3 days after transfer. Exposure of Fundulus heteroclitus to 35 ppt seawater (SW) induced a rise in gill Na+,K+-ATPase activity 3 hr after transfer. After 12 hr, the values dropped to initial levels but showed a second significant increase 3 days after transfer. The absence of detergent in the enzyme assay resulted in lower values of gill Na+,K+-ATPase, and the rapid increase after transfer to SW was not observed. Na+,K+-ATPase activity of gill filaments in vitro for 3 hr increased proportionally to the osmolality of the culture medium (600 mosm/kg > 500 mosm/kg > 300 mosm/kg). Osmolality of 800 mosm/kg resulted in lower gill Na+,K+-ATPase activity relative to 600 mosm/kg. Increasing medium osmolality to 600 mosm/kg with mannitol also increased gill Na+,K+-ATPase. Cycloheximide inhibited the increase in gill Na+,K+-ATPase activity observed in hyperosmotic medium in a dose-dependent manner (10-4 M > 10-5 M > 10-6 M). Actinomycin D or bumetanide in the culture (doses of 10-4 M, 10-5 M, and 10-6 M) did not affect gill Na+,K+-ATPase. Injection of fish with actinomycin D prior to gill organ culture, however, prevented the increase in gill Na+,K+-ATPase activity in hyperosmotic media. The results show a very rapid and transitory increase in gill Na+,K+-ATPase activity in the first hours after the transfer of Fundulus heteroclitus to SW that is dependent on translational and transcriptional processes. (C) 2000 Wiley-Liss, Inc.

  5. EROD activity and antioxidant defenses of sea bass (Dicentrarchus labrax) after an in vivo chronic hydrocarbon pollution followed by a post-exposure period.

    PubMed

    Danion, Morgane; Le Floch, Stéphane; Lamour, François; Quentel, Claire

    2014-12-01

    Chronic concentrations of polycyclic aromatic hydrocarbons (PAHs) have been commonly detected in international estuaries ecosystems. Reliable indicators still need to be found in order to properly assess the impact of PAHs in fish. After an in vivo chronic exposure to hydrocarbons, the enzymatic activity of 7-ethoxyresorufin O-deethylase (EROD) and the antioxidant defense system were assessed in sea bass, Dicentrarchus labrax. A total of 45 fish were exposed to the water-soluble fraction of Arabian crude oil, similar to a complex pollution by hydrocarbons chronically observed in situ, while 45 other control fish sustained the same experimental conditions in clean seawater. Fish samples were made after a 21-day exposure period and after a 15-day recovery period in clean fresh water. Throughout the experiment, liver EROD activity was significantly higher in contaminated fish than in control fish. In addition, nonenzymatic (total glutathione) and enzymatic (GPx, SOD, and CAT) antioxidant defense parameters measured in liver were not significantly different in fish. Furthermore, in gills, glutathione content had significantly increased while SOD activity had significantly decreased in contaminated fish compared to controls. On the other hand, CAT and GPx activities were not affected. Chronic exposure to PAHs disturbing the first step (SOD) and inhibiting the second step (GPx and CAT) could induce oxidative stress in tissues by the formation of oxygen radicals. After the postexposure period, there was no significant difference between control and contaminated fish in any of the antioxidant defense parameters measured in gills, attesting to the reversibility of the effects. PMID:24659404

  6. Active urea transport and an unusual basolateral membrane composition in the gills of a marine elasmobranch.

    PubMed

    Fines, G A; Ballantyne, J S; Wright, P A

    2001-01-01

    In elasmobranch fishes, urea occurs at high concentrations (350-600 mM) in the body fluids and tissues, where it plays an important role in osmoregulation. Retention of urea by the gill against this huge blood-to-water diffusion gradient requires specialized adaptations to the epithelial cell membranes. Experiments were performed to determine the mechanisms and structural features that facilitate urea retention by the gill of the spiny dogfish Squalus acanthias. Analysis of urea uptake by gill basolateral membrane vesicles revealed the presence of a phloretin-sensitive (half inhibition 0.09 mM), sodium-coupled, secondary active urea transporter (Michaelis constant = 10.1 mM, maximal velocity = 0.34 micromol. h(-1). mg protein(-1)). We propose that this system actively transports urea out of the gill epithelial cells back into the blood against the urea concentration gradient. Lipid analyses of the basolateral membrane revealed high levels of cholesterol contributing to the highest reported cholesterol-to-phospholipid molar ratio (3.68). This unique combination of active urea transport and modification of the phospholipid bilayer membrane is responsible for decreasing the gill permeability to urea and facilitating urea retention by the gill of Squalus acanthias. PMID:11124129

  7. Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis).

    PubMed

    Hernroth, B; Baden, S; Tassidis, H; Hörnaeus, K; Guillemant, J; Bergström Lind, S; Bergquist, J

    2016-08-01

    Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65-90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5-3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens. PMID:27288994

  8. Chemical analysis and in vitro EROD activities in extracts from the American oyster

    SciTech Connect

    Gardinali, P.; Willett, K.; Sericano, J.; Safe, S.; Wade, T.

    1995-12-31

    Chemical residue analysis and EROD induction activities were measured in extracts from three groups of American oysters (Crassostrea virginica) after uptake-depuration experiments conduct in Galveston Bay, Texas. Levels of polynuclear aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCD) were determined by HRGC/HRMS and HRGC/HRMS while congener specific polychlorinated biphenyls (PCBs) were determined by HRGC/EC Induction of ethoxyresorufin O-deethylase (EROD) activity by sample extracts were determined in rat hepatoma H4IIE cells. Oysters from Hanna Reef (HR), a relatively clean site in Galveston Bay, were transplanted to a contaminated site in the Houston Ship Channel (SC) area for 48 days. After this exposure period, the remaining oysters were retransplanted to their original (HR) site to study the depuration of the toxic compounds benzo[a]pyrene (BAP), dibenzo[a,h]anthracene (DBA), PCB77, PCB126, PCB105, PCB118, 2,3,7,8-TCDD, and 2,3,7,8-TCDF concentrations were measured during the uptake experiment and used to estimate the corresponding Induction/Toxic TCDD equivalents (I-TEQS) which ranged from 0.13 to 0.499 ng/g. The results demonstrate that BAP and DBA are major contributors to the TCDD induction equivalents (55--76%) of calculated I-TEC compared to PCBs (16--38%) and TCDD/TCDF (5--10%). The bioassay results gave I-TEQs approximately 10 fold higher than the calculated values suggesting that other compounds not detected by HRGC/HRMS, LRMS or ECD were present in the samples and are active as inducers of EROD activity.

  9. EROD activity induction in peripheral blood lymphocytes, liver and brain tissues of rats orally exposed to polycyclic aromatic hydrocarbons.

    PubMed

    Chahin, Abir; Peiffer, Julie; Olry, Jean-Charles; Crepeaux, Guillemette; Schroeder, Henri; Rychen, Guido; Guiavarc'h, Yann

    2013-06-01

    Little is known in terms of multi-matrix cytochrome P450 activity induction under repeated oral exposure to planar halogenated and polycyclic aromatic hydrocarbons (PHH, PAH). In the present study, 60 rats were daily exposed, during 28 days, to oral ingestion of a mixture consisting of phenanthrene, pyrene and benzo(a)pyrene at 0, 6 or 600 μg/day. EROD activity, reflecting almost exclusively CYP1A1 and CYP1B1 activities, was measured in brain and liver microsomes as well as in peripheral blood lymphocytes (PBLs). All induction kinetics could be appropriately fitted using logistic-like models. After 28 days of exposure to a 6 μg/day dose, EROD activity was found to be 91, 152 and 94-fold increased in lymphocytes, liver and brain, respectively, compared to day 0. Plateau activities could be appropriately fitted versus ingested doses using Hill or Michaelis-Menten models. Correlations between matrices made it possible to conclude that EROD activity in PBL should be considered as a sensitive, convenient and non-destructive approach for (i) evaluating EROD activity in liver, which was found to represent 98% of the observed EROD activities in the three tested matrices and (ii) evaluating oral exposure of homogeneous groups of farm animals (race, diet) to CYP inducing PAH and PHH. PMID:23500776

  10. Variation of Basal EROD Activities in Ten Passerine Bird Species – Relationships with Diet and Migration Status

    PubMed Central

    Rainio, Miia J.; Kanerva, Mirella; Wahlberg, Niklas; Nikinmaa, Mikko; Eeva, Tapio

    2012-01-01

    Inter-specific differences in animal defence mechanisms against toxic substances are currently poorly understood. The ethoxyresorufin-O-deethylase (EROD) enzyme plays an important role in defence against toxic chemicals in a wide variety of animals, and it is an important biomarker for environmental contamination. We compared basal hepatic EROD activity levels among ten passerine species to see if there is inter-specific variation in enzyme activity, especially in relation to their diet and migration status. Migratory insectivores showed higher EROD activity compared to granivores. We hypothesize that the variable invertebrate diet of migratory insectivores contains a wider range of natural toxins than the narrower diet of granivores. This may have affected the evolution of mixed function oxidases (MFO) system and enzyme activities. We further tested whether metabolic rates or relative liver size were associated with the variation in detoxification capacity. We found no association between EROD activity and relative (per mass unit) basal metabolic rate (BMR). Instead, EROD activity and relative liver mass (% of body mass) correlated positively, suggesting that a proportionally large liver also functions efficiently. Our results suggest that granivores and non-migratory birds may be more vulnerable to environmental contaminants than insectivores and migratory birds. The diet and migration status, however, are phylogenetically strongly connected to each other, and their roles cannot be fully separated in our analysis with only ten passerine species. PMID:22479477

  11. EROD activity and genotoxicity in the seabob shrimp Xiphopenaeus kroyeri exposed to benzo[a]pyrene (BaP) concentrations.

    PubMed

    da Silva Rocha, Arthur José; Gomes, Vicente; Rocha Passos, Maria José de Arruda Campos; Hasue, Fabio Matsu; Alves Santos, Thaís Cruz; Bícego, Márcia Caruso; Taniguchi, Satie; Van Ngan, Phan

    2012-11-01

    Seabob shrimp Xiphopenaeus kroyeri is a marine species that lives in shallow waters of coastal environments, often impacted by polycyclic aromatic hydrocarbons (PAH) pollution. In the present study, seabob shrimp were exposed for 96 h to benzo[a]pyrene (BaP) at the nominal concentrations of 100, 200, 400 and 800 microg-L(-1). Animals of the control groups were exposed either to clean water or to the BaP-carrier (DMSO). At the end of the exposures, muscle tissues were sampled for BaP uptake assessment and hepatopancreas and hemolymph for EROD enzyme activity and hemocytes DNA damage, respectively. EROD activity and DNA damage increased significantly as a function of BaP exposure concentrations. Significant correlations between BaP uptake and both EROD activity and DNA damage suggest that they can be used as suitable tools for integrated levels of study on the biomarkers of PAH exposure. PMID:22974795

  12. Gills of antarctic fish.

    PubMed

    Rankin, J C; Tuurala, H

    1998-01-01

    We review the literature on the way the structure of icefish gills relates the physiology of these haemoglobin-less fishes. Vascular casting confirmed earlier reports that the only special feature of the gills is the large size of the blood vessels, especially the prominent and continuous marginal channels Isolated perfused gill arches were used to study the effects of changes in afferent and efferent pressure on gill resistance and tritiated water influx in Chionobathyscus dewitti. Increasing perfusion rate did not change gill resistance, but there were moderate proportional increases in water influx. Reducing efferent pressure increased gill resistance but did not affect water influx. In both C. dewitti and Cryodraco antarcticus gills perfused at constant flow rate, noradrenaline produced concentration-dependent decreases in gill resistance and, with high concentrations, increases in water influx. Fixation while perfusion continued was used to compare blood space dimensions in control, noradrenaline-treated and unperfused gills. Noradrenaline caused large increases in the thickness of the lamellar blood space and increased lamellar height, despite a greatly reduced afferent pressure. This suggests that modulation of pillar cell active tension might be involved in control of lamellar perfusion. The possible relationship between gill water fluxes and lamellar recruitment is discussed. PMID:11253779

  13. Polar bear hepatic cytochrome P450: Immunochemical quantitation, EROD/PROD activity and organochlorines

    SciTech Connect

    Letcher, R.J.; Norstrom, R.J. |

    1994-12-31

    Polar bears (Ursus maritimus) are an ubiquitous mammal atop the arctic marine food chain and bioaccumulate lipophilic environmental contaminants. Antibodies prepared against purified rat liver cytochrome P450-1 Al, -1 A2, -2Bl and -3Al enzymes have been found to cross-react with structurally-related orthologues present in the hepatic microsomes of wild polar bears, immunochemically determined levels of P450-1 A and -2B proteins in polar bear liver relative to liver of untreated rats suggested enzyme induction, probably as a result of exposure to xenobiotic contaminants. Optical density quantitation of the most immunochemically responsive isozymes P450-I Al, -IA2 and -2Bi to polygonal rabbit anti-rat P450-IA/IA2 sera and -2BI antibodies in hepatic microsomes of 13 adult male polar bars from the Resolute Bay area of the Canadian Arctic is presented. Correlations with EROD and PROD catalytic activities and levels of organochlorines, such as polychlorinated biphenyls (PCBs), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (p,p-DDE) and their methyl sulfone (MeSO2-) metabolites are made to determine if compound-specific enzyme induction linkages exist. Inter-species immunochemical quantitation of isozymic P450 cytochromes can serve as an indicator of exposure to biologically active contaminant.

  14. Pharmacological control of mucociliary activity in the gill of Mytilus edulis

    SciTech Connect

    Liu, L.F.S.

    1989-01-01

    A series of studies has been carried out, which include the development of a radiolabelling technique for mucous secretion studies, the pharmacological mediation of mucous secretion and ciliary activity, and the identification and localization of cAMP activity in different cell types in the gill filament. A radiolabelling technique was developed using ({sup 14}C)glucosamine as a precursor for the biosynthesis of mucous glycoproteins by the gill tissues. Selective incorporation of the radiolabel into mucous glycoproteins was evident from autoradiographic studies. The mucous secretion was significantly stimulated by serotonin, forskolin, and acetylcholine, and these effects were enhanced or blocked, respectively, by their agonists or antagonists. Interestingly, the stimulatory effect of serotonin on mucous secretion was inhibited by 10{sup {minus}4}M atropine, a cholinergic antagonist, suggesting that the mucous secretion is directly mediated through acetylcholine-induced action rather than the cAMP second messenger system. To further substantiate this hypothesis, a histochemical localization of cAMP in the gill tissue sections was carried out using a horseradish peroxidase conjugated antibody method.

  15. Potassium metabolism in seawater teleosts: II. Evidence for active potassium extrusion across the gill.

    PubMed

    Sanders, M J; Kirschner, L B

    1983-05-01

    Unidirectional K-fluxes were estimated in unanaesthetized trout and sculpin and in anaesthetized sculpin from observed 86Rb movement (JK = 1.3 JRb). In all three groups efflux exceeded influx; Jo/Jin was 2-3. The values predicted by the flux ratio equation were 0.5 for trout and 1.0 for sculpin, so active K-extrusion is indicated. The results also show that more than one half of the total influx must be ingested with food rather than passing across the gills. Flux data show that the gills are more permeable to K+ than to Na+, PK/PNa was 5.4 in trout and 2.6 in sculpin. Changes in K-concentration in the external medium did not appear to affect efflux; there was no exchange component in the total fluxes. When both Na+ and K+ were omitted from the bathing solution, efflux decreased to about 15% of the normal seawater value. This is more than would be expected if the flux were purely diffusive and supports the conclusion that extrusion contains an active component. Repletion of the ion-deficient medium with K+ (alone) increased K-efflux. However, it also repolarized the gill and increased plasma [K+], and the flux change could be accounted for by the augmented driving force; i.e. it was diffusive. The additional plasma K came from the intracellular compartment, rather than an augmented influx from the medium. PMID:6875471

  16. Gill ATPase activity in Procambarus clarkii as an indicator of heavy metal pollution

    SciTech Connect

    Torreblanca, A.; Del Ramo, J.; Diaz-Mayans, J. )

    1989-06-01

    Lake Albufera and the surrounding rice field waters are subjected to very heavy loads of sewage and toxic industrial residues, including heavy metals, from the many urban and waste waters of this area. The American red crayfish, Procambarus clarkii have a high resistance to toxic effects of heavy metals. The sublethal effects of heavy metals on gills of fish and aquatic invertebrates have been extensively studied. Some metabolic disturbances and histologic damages have been reported, as well as osmoregulation alterations. However, little work has been done about the effect of heavy metals on Na,K and Mg-ATPases of freshwater invertebrate gills. Na,K-ATPase is the prime mediator of ion transport across cellular membranes and plays a central role in whole body ion regulation in marine and estuarine animals. Na,K-ATPase has been reviewed and assessed as a potentially useful indicator of pollution stress in aquatic animals. The purpose of this study is look for the relation, if any, between crayfish gill ATP-ase activity changes and metal exposure in laboratory. This find would allow the authors to assay this potential indicator in the field.

  17. Active uptake of sodium in the gills of the hyperregulating shore crab Carcinus maenas

    NASA Astrophysics Data System (ADS)

    Siebers, D.; Lucu, Č.; Winkler, A.; Dalla Venezia, L.; Wille, H.

    1986-03-01

    Isolated posterior gills of shore crabs, Carcinus maenas, previously acclimated for at least 1 month to brackish water of 10 ‰ S, were connected with an artificial hemolymph circulation by means of thin polyethylene tubings. Gills were symmetrically perfused and bathed with 50 % sea water. Transepithelial potential differences (PDs) and fluxes of sodium between medium and blood were measured under control conditions and following reductions of PDs by means of 5 mM internal (blood side) ouabain, 0.5 mM internal and external (bathing medium) NaCN or by exhaustion of energy reserves along with a prolonged perfusion period of more than 9 h. In these experiments22Na was used as tracer. Each of the three modes of reducing transepithelial potential differences resulted in a decrease in sodium influxes from 500 1000 µmoles g-1 h-1 to 250 400 µmoles g-1 h-1. The findings suggest that sodium influx, which normally greatly exceeds efflux, was diminished by its active component. The remaining non-inhibitable influx equals efflux values. Our findings thus indicate that efflux is completely passive, while influx has — beside a passive component of efflux magnitudes — an additional active portion which is much larger than the passive component. Since ouabain is a specific inhibitor of the Na-K-ATPase, our results confirm previous findings (Siebers et al., 1985) that the basolaterally located Na-K-ATPase generates the transepithelial potential difference in the gills, which is inside negative by about 6 12 mV. Inhibition of the active portion of sodium influx by internal ouabain along with reduced PDs suggests that transepithelial PDs generated by the branchial sodium pump are the driving force for active sodium uptake in hyperregulating brackish water crabs.

  18. Eroded Surfaces

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 19 August 2003

    The knobby terrain and eroded impact crater observed in this THEMIS image of the Eumenides Dorsum region are evidence to a surface that has been heavily modified and stripped over time. Variable layering of material within the impact crater suggest a succession of events which eroded the surface and exposed possibly different units. Slope streaks and dust avalanches are also observed within the impact crater and point to recent and continued modification of the surface.

    Image information: VIS instrument. Latitude 4.9, Longitude 203.6 East (156.4 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Dietary choline regulates antibacterial activity, inflammatory response and barrier function in the gills of grass carp (Ctenopharyngodon idella).

    PubMed

    Zhao, Hua-Fu; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu; Feng, Lin

    2016-05-01

    An 8-week feeding trial was conducted to determine the effects of graded levels of choline (197-1795 mg/kg) on antibacterial properties, inflammatory status and barrier function in the gills of grass carp. The results showed that optimal dietary choline supplementation significantly improved lysozyme and acid phosphatase activities, complement component 3 (C3) content, and the liver expressed antimicrobial peptide 2 and Hepcidin mRNA levels in the gills of fish (P < 0.05). In addition, appropriate dietary choline significantly decreased the oxidative damage, which might be partly due to increase copper, zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutathione reductase (GR) activities and increased glutathione content in the gills of fish (P < 0.05). Moreover, appropriate dietary choline significantly up-regulated the mRNA levels of interleukin 10 and transforming growth factor β1, Zonula occludens 1, Occludin, Claudin-b, c, 3 and 12, inhibitor of κBα, target of rapamycin, Cu/Zn-SOD, CAT, GR, GPx, GST and NF-E2-related factor 2 in the gills of fish (P < 0.05). Conversely, appropriate dietary choline significantly down-regulated the mRNA levels of pro-inflammatory cytokines, tumor necrosis factor α, interleukin 8, interferon γ, interleukin 1β, and related signaling factors, nuclear factor kappa B p65, IκB kinase β, IκB kinase γ, myosin light chain kinase and Kelch-like-ECH-associated protein 1a (Keap1a) in the gills of fish (P < 0.05). However, choline did not have a significant effect on the mRNA levels of IκB kinase α, Claudin-15 and Keap1b in the gills of fish. Collectively, appropriate dietary choline levels improved gill antibacterial properties and relative gene expression levels of tight junction proteins, and decreased inflammatory status, as well as up-regulated the mRNA levels of related signaling molecules in the gills of fish. Based on gill C3 content and AHR

  20. Soil erosion increases soil microbial activity at the depositional position of eroding slopes

    NASA Astrophysics Data System (ADS)

    Meng, Xu; Cardenas, Laura M.; Donovan, Neil; Zhang, Junling; Murray, Phil; Zhang, Fusuo; Dungait, Jennifer A. J.

    2016-04-01

    Soil erosion is the most widespread form of soil degradation. Estimation of the impact of agricultural soil erosion on global carbon cycle is a topic of scientific debate, with opposing yet similar magnitude estimates of erosion as a net source or sink of atmospheric carbon. The transport and deposition of eroded agricultural soils affects not only the carbon cycle but other nutrient cycles as well. It has been estimated that erosion-induced lateral fluxes of nitrogen (N) and phosphorus (P) could be similar in magnitude to those from fertilizer application and crop removal (Quinton et al., 2010). In particular, the dynamics of soil N in eroding slopes need to be considered because the management of soil N has profound influences on the functioning of soil microorganisms, which are generally considered as the main biotic driver of soil C efflux. Carbon dioxide (CO2) emissions tend to increase in deposition positions of eroded slopes, diminishing the sink potential of eroded soils C (. As the global warming potential of nitrous oxide (N2O) is 310 times relative to that of CO2, the sink potential of agricultural erosion could easily be negated with a small increase in N2O emissions. Therefore, an investigation of the potential emissions of greenhouse gases, and especially N2O from soils affected by agricultural erosion, are required. In the present study, a field experiment was established with contrasting cultivation techniques of a C4 crop (Zea mays; δ13C = -12.2‰) to introduce 13C-enriched SOC to a soil previously cropped with C3 plants (δ13C = -29.3‰). Soils sampled from the top, middle, bottom and foot slope positions along a distinct erosion pathway were analyzed using 13C-phospholipid fatty acid (PLFA) analysis and incubated to investigate the responses of microorganisms and associated potential emissions of greenhouse gases (GHG). The total C and N contents were greatest in soils at the top slope position, whereas soil mineral N (NO3--N and NH4+-N

  1. Induction of in vitro EROD activity and in vivo caffeine metabolism in two species of New Zealand birds.

    PubMed

    Numata, Mihoko; Fawcett, J Paul; Rosengren, Rhonda J

    2008-05-01

    In birds, induction of cytochrome P4501A (CYP1A) is usually assessed as liver microsomal ethoxyresorufin O-deethylase (EROD) activity, but in mammals, it can be determined by a caffeine metabolism blood test. We investigated both of these measures in two species of New Zealand birds. Administration of a model CYP1A inducer, β-naphthoflavone (BNF) (80mg/kg i.p. twice 2 days apart), to paradise shelducks (Tadorna variegata; herbivore) and southern black-backed gulls (Larus dominicanus; omnivore) (n=5 or 6) caused marked increases in EROD activity (80- and 20-fold, respectively). In both species, BNF treatment also caused significant increases (>8-fold) in caffeine metabolism determined prior to sacrifice as the serum concentration ratio of the major metabolite, paraxanthine, to caffeine, after caffeine administration (1mg/kg i.p.). The results suggest in vivo caffeine metabolism is a potentially useful non-destructive biomarker of CYP1A induction in wild birds. PMID:21783874

  2. Inhibition of ethoxyresorufin-O-deethylase (EROD) activity in mixtures of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and polychlorinated biphenyls (PCBs)

    SciTech Connect

    Tysklind, M.; Rappe, C.; Bosveld, A.T.C.; Sinnige, T.; Verhallen, E.; Berg, M. van den

    1995-12-31

    In the chicken liver, both cytochrome P450 1A1 and 1A2 have been found to be inducible by TCDD and other ``dioxin-like`` compounds. Induced cytochrome P450 1A1/2 monooxygenase activity is also suggested to affect the regulation of heme biosynthesis and to result in an increase of liver uroporphyrins, as well as other forms of porphyrins. 2,3,7,8-TCDD, 2,2{prime},4,6,6{prime}-PeCB (PCB{number_sign}104), and 2,2{prime},4,4{prime},5,5{prime}-HxCB (PCB{number_sign}153) were dosed to primary chicken embryo hepatocytes and effects on EROD activities and porphyrin accumulation were measured. Among the three compounds, only TCDD elicit measurable catalytic EROD activity (EC{sub 50} at 0.01 nM). However, all three compounds showed increased porphyrin concentrations at doses higher than 1 nM, 100 nM, and 50 nM, respectively. In the dose range, the porphyrin accumulation concur with a decrease in EROD activity. In order to study possible interaction between the two classes of compounds, chicken hepatocytes were dosed with mixtures of TCDD and PCB{number_sign}104 and PCB{number_sign}153, respectively. The combination of TCDD and the ortho-substituted PCBs (at doses which cause porphyrin accumulation) have an inhibitory effect on TCDD-induced EROD activity. The results support that there are nonadditive interactions between different classes of polyaromatic compounds, such as TCDD and ortho-substituted PCBs. The inhibition of the EROD activity could lead to a change in the dose-response curve, thereby influencing the EC{sub 50}-value, and thus great care should be taken when using EROD activity as a sum parameter for dioxin-like activity of complex environmental mixtures.

  3. Evaluation of liver histopathology and EROD activity in St. Lawrence lake sturgeon (Acipenser fulvescens) in comparison with a reference population

    SciTech Connect

    Rousseaux, C.G. ||; Branchaud, A.; Spear, P.A.

    1995-05-01

    In an attempt to evaluate the effects of contaminants on the lake sturgeon Acipenser fulvescens, fish were netted from two sites: Riviere des Prairies, confluent with the St. Lawrence River near Montreal, and a reference site on the upper reaches of the Ottawa River in the La Verendrye Park. Livers of fish collected from the Riviere des Prairies were difficult to homogenize, and they left behind strands of what appeared to be connective tissue. Suspecting hepatic fibrosis, the authors decided to evaluate the livers for histopathologic changes. Nineteen adult lake sturgeon (eleven male and eight female) were examined. Following fixation, routine processing, sectioning, and staining with hematoxylin and eosin, microscopic evaluation revealed the following: Sections taken from livers of fish from the Riviere des Prairies site showed excessive fat accumulation and often severe chronic-active cholangiohepatitis. Bile duct proliferation (p < 0.0001), periportal fibrosis (p < 0.0001), inflammation (p < 0.001), and fat accumulation (p < 0.05) were more pronounced in the fish from the Riviere des Prairies site. Melano-macrophage centers appeared to be both paler and gave the appearance of fewer numbers (p < 0.01). Livers from lake sturgeon taken from the reference site had a more normal appearance. The EROD levels were also significantly induced in these fish (reference 3.39 {+-} 0.57; Riviere des Prairies site 8.21 {+-} 0.87 pmol/mg protein/min; p < 0.0005). The EROD levels positively correlated with bile duct proliferation (r{sup 2} = 0.44; p = 0.001) and periportal fibrosis (r{sup 2} = 0.41; p = 0.002). Despite the statistical associations above, the authors cannot categorically state that contaminants are the sole cause of the lesions seen.

  4. Effect of atrazine and chlorpyrifos exposure on cytochrome P450 contents and enzyme activities in common carp gills.

    PubMed

    Fu, Yao; Li, Ming; Liu, Ci; Qu, Jian-Ping; Zhu, Wen-Jun; Xing, Hou-Juan; Xu, Shi-Wen; Li, Shu

    2013-08-01

    Chlorpyrifos (CPF) and atrazine (ATR) are the most widely used organophosphate insecticides and triazine herbicides, respectively, worldwide. This study aimed at investigating the effects of ATR, CPF and mixture on common carp gills following 40-d exposure and 40-d recovery experiments. Cytochrome P450 content, activities of aminopyrine N-demethylase (APND) and erythromycin N-demethylase (ERND) and the mRNA levels of the CYP1 family (CYP1A, CYP1B, and CYP1C) were determined. In total, 220 common carps were divided into eleven groups, and each group was treated with a specific concentration of ATR (4.28, 42.8 and 428 μg/L), CPF (1.16, 11.6 and 116 μg/L) or ATR-CPF mixture (1.13, 11.3 and 113 μg/L). The results showed that P450 content and activities of APND and ERND in fish exposed to ATR and mixture were significantly higher than those in the control group. After the 40-d recovery treatment (i.e., depuration), the P450 content and the activities of APND and ERND in fish decreased to the background levels. A similar tendency was also found in the mRNA levels of the CYP1 family (CYP1A, CYP1B, and CYP1C) in common carp gills. The CPF-treated fish showed no significant difference from the control groups, except for a significant CYP1C induction. These results indicated that CYP enzyme levels are induced by ATR but were only slightly affected by CPF in common carp gills. In addition, the ATR and CPF exposure showed an antagonistic effect on P450 enzymes in common carp gills. PMID:23702303

  5. Effects of white spot syndrome virus infection on immuno-enzyme activities and ultrastructure in gills of Cherax quadricarinatus.

    PubMed

    Wang, Dan-Li; Zuo, Di; Wang, Lan-Mei; Sun, Ting; Wang, Qun; Zhao, Yun-Long

    2012-05-01

    In this study, we explored the pathogenic mechanism of white spot syndrome virus (WSSV) in crayfish, Cherax quadricarinatus, by investigating activities of enzymes related to innate immune function during infection. After 6-12 h of exposure to WSSV, the activities of four enzymes, phenoloxidase (PO), peroxidase (POD), superoxide dismutase (SOD) and lysozyme (LSZ), increased in the gills of C. quadricarinatus but then sharply decreased during longer infection times. Except for PO, the activities of other enzymes in the WSSV-infected crayfish (Group II) were significantly lower than those of the controls at 72 h post-exposure (P < 0.01). Interestingly, the enzyme activities in the group treated with polysaccharides before challenge with WSSV (Group III) were higher than those in Group II. This phenomenon demonstrated that the polysaccharides could improve the immuno-enzyme activities and enhance the organism's antiviral defenses. Morphological examination by transmission electron microscopy revealed abundant WSSV particles and significant damage in the gills of infected crayfish. WSSV infection caused parts of the gill epithelium and microvilli to be reduced in number and size or damaged; meanwhile, the mitochondria morphology changed, with parts of the cristae diminished leaving large vacuoles. Moreover, electron dense deposits appeared and heterochromatinized nuclei could be seen in blood cells with ruptured nuclear membranes and outflow of nucleoplasm. The findings of this study furthers our understanding of the biochemical alterations induced by viral infections, including changes in the antioxidant status, oxidative stress and lysozyme activity, which could help to advance strategies for control of WSSV in crayfish. PMID:22281607

  6. In vivo changes in carbonic anhydrase activity and histopathology of gill and liver tissues after acute exposure to chlorpyrifos in rainbow trout.

    PubMed

    Topal, Ahmet; Atamanalp, Muhammed; Oruç, Ertan; Demir, Yeliz; Beydemir, Şükrü; Işık, Alparslan

    2014-12-01

    Chlorpyrifos is an organophosphate pesticide widely used in agriculture and aquaculture. This study investigated its effects on carbonic anhydrase (CA) enzyme activity and histopathology of rainbow trout gill and liver. The fish were exposed to 2.25 (25% of 96 h LC50), 4.5 (50% of 96 h LC50), and 6.75 μg L⁻¹ (75% of 96 h LC50) of chlorpyrifos for 24, 48, 72, and 96 h. CA activity was measured in liver and gills and histopathological changes were examined by light microscopy. The most common liver changes at most of the chlorpyrifos concentrations were hyperaemia and degenerative changes. Gill tissues were characterised by lamellar hyperaemia, lamellar oedemas, clumping, cellular degeneration, hyperplasia, and lamellar atrophy. CA enzyme activity in the gills decreased at all concentrations at 48, 72, and 96 h after exposure to chlorpyrifos (p<0.05). Similarly, there was a time-dependent decrease in CA activity at all of the concentrations in liver tissues (p<0.05). The present study indicated that chlorpyrifos inhibits CA enzyme activity and causes histopathological damage in gill and liver tissues. PMID:25720025

  7. Primary cultured cells as sensitive in vitro model for assessment of toxicants--comparison to hepatocytes and gill epithelia.

    PubMed

    Zhou, Bingsheng; Liu, Chunsheng; Wang, Jingxian; Lam, Paul K S; Wu, Rudolf S S

    2006-11-16

    In an effort to develop cultured cell models for toxicity screening and environmental biomonitoring, we compared primary cultured gill epithelia and hepatocytes from freshwater tilapia (Oreochromis niloticus) to assess their sensitivity to AhR agonist toxicants. Epithelia were cultured on permeable supports (terephthalate membranes, "filters") and bathed on the apical with waterborne toxicants (pseudo in vivo asymmetrical culture conditions). Hepatocytes were cultured in multi-well plates and exposed to toxicants in culture medium. Cytochrome P4501A (measured as 7-Ethoxyresorufin-O-deethylase, EROD) was selected as a biomarker. For cultured gill epithelia, the integrity of the epithelia remained unchanged on exposure to model toxicants, such as 1,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), benzo(a)pyrene B[a]P, polychlorinated biphenyl (PCB) mixture (Aroclor 1254), and polybrominated diphenyl ether (PBDE) mixture (DE71). A good concentration-dependent response of EROD activity was clearly observed in both cultured gill epithelia and hepatocytes. The time-course response of EROD was measured as early as 3h, and was maximal after 6h of exposure to TCDD, B[a]P and Aroclor 1254. The estimated 6h EC50 for TCDD, B[a]P, and Aroclor 1254 was 1.2 x 10(-9), 5.7 x 10(-8) and 6.6 x 10(-6)M. For the cultured hepatocytes, time-course study showed that a significant induction of EROD took place at 18 h, and the maximal induction of EROD was observed at 24h after exposure. The estimated 24h EC50 for TCDD, B[a]P, and Aroclor 1254 was 1.4 x 10(-9), 8.1 x 10(-8) and 7.3 x 10(-6)M. There was no induction or inhibition of EROD in DE71 exposure to both gill epithelia and hepatocytes. The results show that cultured gill epithelia more rapidly induce EROD and are slightly more sensitive than cultured hepatocytes, and could be used as a rapid and sensitive tool for screening chemicals and monitoring environmental AhR agonist toxicants. PMID:16959333

  8. Preliminary study of gill NA+,K+-ATPase activity in juvenile spring chinook salmon following electroshock or handling stress

    USGS Publications Warehouse

    VanderKooi, S.P.; Gale, William L.; Maule, A.G.

    2000-01-01

    We compared gill Na+,K+-ATPase in subyearling and yearling spring chinook salmon Oncorhynchus tshawytscha 3 h, 24 h, and 7 d after exposure to either a short pulsed DC electroshock (300 V, 50 Hz, 8-ms pulse duration) or an acute handling stress. Mean gill Na+,K+-ATPase values ranged from 7.5 to 11.8 ??mol inorganic phosphate (Pi) ?? (mg protein)-1 ?? h-1. No significant differences were detected, with the exception of electroshocked subyearlings 7 d after treatment. Increased activity was attributed to the presence of two influential values. No significant differences were detected after removal of these observations, so the increase was not considered biologically significant. Inclusion of the outliers did not alter our interpretation of the results given that the observed increase was slight compared with the magnitude of changes reported under experimental conditions and in migrating juvenile salmonids. The treatment groups underwent a typical stress response and had significantly elevated cortisol and glucose levels 3 h after treatment. Recovery to control levels occurred within 24 h for cortisol and from 24 h to 7 d for glucose. Our results lead to the conclusion that neither acute electroshock nor acute handling stress alters Na+,K+-ATPase activity in juvenile spring chinook salmon.

  9. Selenoprotein M gene expression, peroxidases activity and hydrogen peroxide concentration are differentially regulated in gill and hepatopancreas of the white shrimp Litopenaeus vannamei during hypoxia and reoxygenation.

    PubMed

    García-Triana, Antonio; Peregrino-Uriarte, Alma Beatriz; Yepiz-Plascencia, Gloria

    2016-09-01

    In many organisms, episodes of low O2 concentration (hypoxia) and the subsequent rise of O2 concentration (reoxygenation) result in the accumulation of reactive oxygen species and oxidative stress. Selenoprotein M (SelM), is a selenocysteine containing protein with redox activity involved in the antioxidant response. It was previously shown that in the white shrimp Litopenaeus vannamei, the silencing of SelM by RNAi decreased peroxidase activity in gill. In this work, we report the structure of the SelM gene (LvSelM) and its relative expression in hepatopancreas and gill after 24h of hypoxia followed by 1h of reoxygenation. The gene is composed by four exons interrupted by tree introns. In gills and hepatopancreas, SelM expression increased after 24h of hypoxia followed by 1h of reoxygenation, while peroxidases activity diminished in hepatopancreas but increased in gills. Hydrogen peroxide (H2O2) concentration was higher in hepatopancreas in response to hypoxia for 6h and did not change after 24 of hypoxia followed by reoxygenation; conversely, no change was detected in gill. SelM appears to be a key enzyme in gill oxidative stress regulation, since the higher expression is associated with an increase in peroxidases activity while maintaining H2O2 concentration. In contrast, in hepatopancreas there is a higher expression after hypoxia and reoxygenation for 24h, but peroxidases activity was lower and the change in H2O2 occurred after 6h of hypoxia and this level was maintained during reoxygenation. PMID:27112516

  10. Gill-specific (Na(+), K(+))-ATPase activity and α-subunit mRNA expression during low-salinity acclimation of the ornate blue crab Callinectes ornatus (Decapoda, Brachyura).

    PubMed

    Leone, Francisco A; Garçon, Daniela P; Lucena, Malson N; Faleiros, Rogério O; Azevedo, Sergio V; Pinto, Marcelo R; McNamara, John C

    2015-08-01

    We evaluate (Na(+), K(+))-ATPase activity, and protein and gene expression of the α-subunit in posterior gills 6 and 7 of Callinectes ornatus, a euryhaline crab, during a 10-day acclimation period from seawater (33‰ S) to low salinity (21‰ S). (Na(+), K(+))-ATPase activity decreased within 1h after transfer to 21‰ S, values recovering by 24h and attaining a maximum of ≈180 nmol Pi min(-1) mg(-1) after 10 days (≈2.5-fold increase). (Na(+), K(+))-ATPase activity is ≈1.5-fold greater in gill 6 than in gill 7, independently of salinity. Relative expression of (Na(+), K(+))-ATPase α-subunit mRNA increased in both gills within 1- to 2-h exposure to low salinity, reaching an ≈8-fold maximum after 24-h exposure, decreasing slightly by 10 days acclimation to low salinity. This increase in α-subunit mRNA expression may underpin the increased (Na(+), K(+))-ATPase activity seen after 10 days acclimation to low salinity. Enzyme affinity for ATP was greater in gill 6 than in gill 7, in contrast to ouabain affinity that was greater in gill 7. Western blotting analysis identified a single immunoreactive band against the (Na(+), K(+))-ATPase α-subunit with an Mr of ≈105 kDa, independently of gill number and low salinity acclimation. Despite these differences, gills 6 and 7 appear to perform similar functions in salt uptake from the dilute medium. The partial cDNA sequence obtained for the gill (Na(+), K(+))-ATPase of C. ornatus (GenBank deposit KF056804) showed 97 to 91% identities with similar sequences from other portunid crab gills. The regulation of gill (Na(+), K(+))-ATPase activity during acclimation to low salinity is discussed. PMID:25934083

  11. ROSETTE GLANDS IN THE GILLS OF THE GRASS SHRIMP, 'PALAEMONETES PUGIO' I. COMPARATIVE MORPHOLOGY, CYCLICAL ACTIVITY, AND INNERVATION

    EPA Science Inventory

    Two types of exocrine rosette glands (type A and type B), located in the gill axes of the grass shrimp, Palaemonetes pugio, are described. The type A glands are embedded within the longitudinal median spetum of the gill axes, whereas the type B glands typically project into the e...

  12. Binding of nickel and copper to fish gills predicts toxicity when water hardness varies, but free-ion activity does not

    SciTech Connect

    Meyer, J.S.; Bobbitt, J.P.; Debrey, L.D.; Boese, C.J.; Bergman, H.L.; Santore, R.C.; Paquin, P.R.; Ditoro, D.M.; Allen, H.E.

    1999-03-15

    Based on a biotic-ligand model (BLM), the authors hypothesized that the concentration of a transition metal bound to fish gills ([M{sub gill}]) will be a constant predictor of mortality, whereas a free-ion activity model is generally interpreted to imply that the chemical activity of the aquo (free) ion of the metal will be a constant predictor of mortality. In laboratory tests, measured [Ni{sub gill}] and calculated [Cu{sub gill}] were constant predictors of acute toxicity of Ni and Cu to fathead minnows (Pimephales promelas) when water hardness varied up to 10-fold, whereas total aqueous concentrations and free-ion activities of Ni and Cu were not. Thus, the BLM, which simultaneously accounts for (a) metal speciation in the exposure water and (b) competitive binding of transition-metal ions and other cations to biotic ligands predicts acute toxicity better than does free-ion activity of Ni or Cu. Adopting a biotic-ligand modeling approach could help establish a more defensible, mechanistic basis for regulating aqueous discharges of metals.

  13. Effect of salinity on hemolymph osmotic pressure, sodium concentration and Na+-K+-ATPase activity of gill of Chinese crab, Eriocheir sinensis

    NASA Astrophysics Data System (ADS)

    Liu, Hongyu; Pan, Luqing; Fu, Lü

    2008-02-01

    The effects of salinity on hemolymph osmotic pressure, Na+ concentration and Na+-K+-ATPase activity of gill of Chinese crab Eriocheir sinensis were studied. The results showed that hemolymph osmotic pressure and Na+ concentration increased significantly ( P<0.05), and the Na+-K+-ATPase activity of gills decreased significantly ( P<0.05) when salinity increased from 0 to 16. The hemolymph osmotic pressure and Na+ concentration in each treatment group rose remarkably at 0.125 d or 0.25 d, while the Na+-K+-ATPase activity of gill reduced gradually with increased experiment time in 3 d. Then the three parameters remained at a constant level after 0.25 d, 0.125 d and 3 d, respectively, and higher hemolymph osmotic pressure, higher Na+ concentration and lower Na+-K+-ATPase activity of gill occurred at higher salinity. The effect of salinity change on protein concentration of hemolymph was indistinct ( P>0.05); However, the protein concentration decreased gradually with the increase of salinity from 0.25 d to 1 d, and then tended to be stable from day 1 to day 15.

  14. Wind-Eroded Landscape

    NASA Technical Reports Server (NTRS)

    2005-01-01

    5 August 2005 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a dust-mantled, wind-eroded landscape in the Medusae Sulci region of Mars. Wind eroded the bedrock in this region, and then, later, windblown dust covered much of the terrain.

    Location near: 5.7oS, 160.2oW Image width: width: 3 km (1.9 mi) Illumination from: lower left Season: Southern Spring

  15. Relationship between aryl hydrocarbon receptor-affinity and the induction of EROD activity by 2,3,7,8-tetrachlorinated phenothiazine and derivatives

    SciTech Connect

    Fried, Kristian W.; Bazzi, Rana; Levy Lopez, Walkiria; Corsten, Claudia; Schramm, Karl-Werner; Bell, David R.; Rozman, Karl K.

    2007-10-15

    Reported herein are semi-empirical calculations of the molecular geometry of TCDD, TCPT, TCPT-sulfoxide (TCPT-O), TCPT-sulfone (TCPT-O{sub 2}), N-methyl-TCPT (Me-TCPT), N-methyl-TCPT-sulfoxide (Me-TCPT-O), and N-methyl-TCPT-sulfone (Me-TCPT-O{sub 2}), the characterization of their AhR binding affinity in rat hepatic cytosol, and their ability to induce EROD activity in a rat hepatoma cell line in vitro. Semi-empirical calculations yielded detailed information about the stereochemistry and the preferred conformation of each of these compounds. These results in combination with observations reported in this paper were used to determine structure-activity relationships. In vitro displacement of {sup 3}H-TCDD was measured by increasing concentrations of the respective ligands. This assay revealed a strong binding affinity of TCPT to the AhR with a K{sub i} value of 1.08 nM. TCDD had a K{sub i} value of 0.54 nM. The affinity of TCPT derivatives for the AhR decreased with increasing degree of oxidation. Moreover, N-methylation further lowered the affinity, so that the N-methyl sulfone derivative of TCPT displayed the highest K{sub i} at {approx} 1200 nM (= 460.4 ng/ml). A corresponding trend was observed regarding the potency of TCPT and derivatives to induce EROD activity in vitro. However, the potencies were considerably lower than that of TCDD. Enzyme induction was measured in a rat hepatoma cell line H4IIEC/T3 by quantification of ethoxyresorufin-O-deethylase (EROD) activity. Induction was measured at 12, 24, 48 and 72 h to determine time dependence. Sulfoxidated and N-methylated phenothiazines displayed a lower potency than their respective parent compounds. TCPT and all derivatives induced enzyme activity at an efficacy similar to TCDD at all time points measured. The reported findings clearly separate the induction of EROD activity by TCPT and derivatives from their binding affinities to the AhR. In contrast, a direct correlation between the two is generally

  16. D1-like dopamine receptors downregulate Na+-K+-ATPase activity and increase cAMP production in the posterior gills of the blue crab Callinectes sapidus.

    PubMed

    Arnaldo, Francis B; Villar, Van Anthony M; Konkalmatt, Prasad R; Owens, Shaun A; Asico, Laureano D; Jones, John E; Yang, Jian; Lovett, Donald L; Armando, Ines; Jose, Pedro A; Concepcion, Gisela P

    2014-09-15

    Dopamine-mediated regulation of Na(+)-K(+)-ATPase activity in the posterior gills of some crustaceans has been reported to be involved in osmoregulation. The dopamine receptors of invertebrates are classified into three groups based on their structure and pharmacology: D1- and D2-like receptors and a distinct invertebrate receptor subtype (INDR). We tested the hypothesis that a D1-like receptor is expressed in the blue crab Callinectes sapidus and regulates Na(+)-K(+)-ATPase activity. RT-PCR, using degenerate primers, showed the presence of D1βR mRNA in the posterior gill. The blue crab posterior gills showed positive immunostaining for a dopamine D5 receptor (D5R or D1βR) antibody in the basolateral membrane and cytoplasm. Confocal microscopy showed colocalization of Na(+)-K(+)-ATPase and D1βR in the basolateral membrane. To determine the effect of D1-like receptor stimulation on Na(+)-K(+)-ATPase activity, intact crabs acclimated to low salinity for 6 days were given an intracardiac infusion of the D1-like receptor agonist fenoldopam, with or without the D1-like receptor antagonist SCH23390. Fenoldopam increased cAMP production twofold and decreased Na(+)-K(+)-ATPase activity by 50% in the posterior gills. This effect was blocked by coinfusion with SCH23390, which had no effect on Na(+)-K(+)-ATPase activity by itself. Fenoldopam minimally decreased D1βR protein expression (10%) but did not affect Na(+)-K(+)-ATPase α-subunit protein expression. This study shows the presence of functional D1βR in the posterior gills of euryhaline crabs chronically exposed to low salinity and highlights the evolutionarily conserved function of the dopamine receptors on sodium homeostasis. PMID:25080496

  17. Benzo(a)pyrene Metabolism and EROD and GST Biotransformation Activity in the Liver of Red- and White-Blooded Antarctic Fish.

    PubMed

    Strobel, Anneli; Burkhardt-Holm, Patricia; Schmid, Peter; Segner, Helmut

    2015-07-01

    Climate change and anthropogenic pollution are of increasing concern in remote areas such as Antarctica. The evolutionary adaptation of Antarctic notothenioid fish to the cold and stable Southern Ocean led to a low plasticity of their physiological functions, what may limit their capacity to deal with altered temperature regimes and pollution in the Antarctic environment. Using a biochemical approach, we aimed to assess the hepatic biotransformation capacities of Antarctic fish species by determining (i) the activities of ethoxyresorufin-O-deethylase (EROD) and glutathione-S-transferase (GST), and (ii) the metabolic clearance of benzo(a)pyrene by hepatic S9 supernatants. In addition, we determined the thermal sensitivity of the xenobiotic biotransformation enzymes. We investigated the xenobiotic metabolism of the red-blooded Gobionotothen gibberifrons and Notothenia rossii, the hemoglobin-less Chaenocephalus aceratus and Champsocephalus gunnari, and the rainbow trout Oncorhynchus mykiss as a reference. Our results revealed similar metabolic enzyme activities and metabolic clearance rates between red- and white-blooded Antarctic fish, but significantly lower rates in comparison to rainbow trout. Therefore, bioaccumulation factors for metabolizable lipophilic contaminants may be higher in Antarctic than in temperate fish. Likewise, the thermal adaptive capacities and flexibilities of the EROD and GST activities in Antarctic fish were significantly lower than in rainbow trout. As a consequence, increasing water temperatures in the Southern Ocean will additionally compromise the already low detoxification capacities of Antarctic fish. PMID:25965896

  18. Innervation of Gill Lateral Cells in the Bivalve Mollusc Crassostrea virginica Affects Cellular Membrane Potential and Cilia Activity

    PubMed Central

    Catapane, Edward J; Nelson, Michael; Adams, Trevon; Carroll, Margaret A

    2016-01-01

    Gill lateral cells of Crassostrea virginica are innervated by the branchial nerve, which contains serotonergic and dopaminergic fibers that regulate cilia beating rate. Terminal release of serotonin or dopamine results in an increase or decrease, respectively, of cilia beating rate in lateral gill cells. In this study we used the voltage sensitive fluorescent probe DiBAC4(3) to quantify changes in gill lateral cell membrane potential in response to electrical stimulation of the branchial nerve or to applications of serotonin and dopamine, and correlate these changes to cilia beating rates. Application of serotonin to gill lateral cells caused prolonged membrane depolarization, similar to plateau potentials, while increasing cilia beating rate. Application of dopamine hyperpolarized the resting membrane while decreasing cilia beating rate. Low frequency (5 Hz) electrical stimulations of the branchial nerve, which cause terminal release of endogenous serotonin, or high frequency (20 Hz) stimulations, which cause terminal release of endogenous dopamine, had the same effects on gill lateral cell membrane potentials and cilia beating rate as the respective applications of serotonin or dopamine. The study shows that innervation of gill lateral cells by the branchial nerve affects membrane potential as well as cilia beating rate, and demonstrates a strong correlation between changes in membrane potential and regulation of cilia beating rate. The study furthers the understanding of serotonin and dopamine signaling in the innervation and regulation of gill cilia in bivalves. The study also shows that voltage sensitive fluorescent probes like DiBAC 4(3) can be successfully used as an alternative to microelectrodes to measure changes in membrane potential of ciliated gill cells and other small cells with fast moving cilia. PMID:27489887

  19. Structural lipid changes and Na(+)/K(+)-ATPase activity of gill cells' basolateral membranes during saltwater acclimation in sea lamprey (Petromyzon marinus, L.) juveniles.

    PubMed

    Lança, Maria João; Machado, Maria; Ferreira, Ana Filipa; Quintella, Bernardo Ruivo; de Almeida, Pedro Raposo

    2015-11-01

    Seawater acclimation is a critical period for anadromous species and a process yet to be understood in lampreys. Considering that changes in lipid composition of the gill cells' basolateral membranes may disrupt the major transporter Na(+)K(+)-ATPase, the goal of this study was to detect changes at this level during juvenile sea lamprey seawater acclimation. The results showed that saltwater acclimation has a direct effect on the fatty acid composition of gill cells basolateral membrane's phospholipids. When held in full-strength seawater, the fatty acid profile of basolateral membrane's phospholipids suffered a restructure by increasing either saturation or the ratio between oleic acid and eicosapentaenoic acid. Simultaneously, the activity of Na(+)K(+)-ATPase revealed a significant and positive correlation with basolateral membrane's cholesterol content in the presence of highest salinity. Our results pointed out for lipid adjustments involving the functional transporter present on the gill cell basolateral membranes to ensure the role played by branchial Na(+)K(+)-ATPase in ion transport during saltwater acclimation process. The responses observed contributed to the strategy adopted by gill cell's basolateral membranes to compensate for osmotic and ionic stressors, to ensure the success of the process of seawater acclimation associated with the downstream trophic migration of juvenile sea lamprey. PMID:26244517

  20. Eroded Sedimentary Rock

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-372, 26 May 2003

    This high resolution Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows eroded, layered sedimentary rock exposures in an unnamed western Arabia Terra crater at 8oN, 7oW. The dark material is windblown sand; much of the erosion of these layers may have also been caused by wind. Sunlight illuminates the scene from the left.

  1. Adaptive alterations on gill Na⁺, K⁺-ATPase activity and mitochondrion-rich cells of juvenile Acipenser sinensis acclimated to brackish water.

    PubMed

    Zhao, Feng; Wu, Beibei; Yang, Gang; Zhang, Tao; Zhuang, Ping

    2016-04-01

    Understanding the physiological changes and osmoregulatory strategy is critical for anadromous species to adapt to large changes between freshwater and marine environments. In this study, juvenile Chinese sturgeon (Acipenser sinensis) were acclimated for 2 months to freshwater (FW, c. 0‰) and brackish water (BW, 15‰). Blood was assessed for changes in osmolality and ions. Gill tissue was assayed for Na(+), K(+)-ATPase (NKA) activity and immunohistochemical analysis on mitochondria-rich cells (MRCs). Serum osmolality and ions concentrations (Na(+), Cl(-) and K(+)) examined, except K(+), increased significantly in those specimens adapted to BW. However, the variations were within the range of effective hyperosmotic adaptation. The specific activity of gill NKA of juveniles adapted to BW was significantly higher (c. 1.6 times) than that of fish adapted to FW. MRCs were mainly presented in the interlamellar region of the filament and at the base of the lamella in either FW- or BW-acclimated individuals. In BW, the number and size of MRCs on filaments greatly increased. However, there was no significant difference in the number and size of the MRCs at the lamella region. Results show that juvenile Chinese sturgeon keep osmotic homeostasis in hyperosmotic environments by increasing gill NKA activity and MRCs' size and number, which is similar to other sturgeons and euryhaline teleosts. PMID:26614501

  2. Biochemical responses in the gills of Meretrix meretrix after exposure to treated municipal effluent.

    PubMed

    Wan, Ru; Meng, Fanping; Fu, Wenchao; Wang, Qun; Su, Enping

    2015-01-01

    The biochemical effects in marine bivalves exposed to increasing concentrations of treated municipal effluent (TME), as discharged into receiving marine waters, are investigated. The effluent was collected from a municipal sewage treatment plant (STP) in Qingdao (China). Meretrix meretrix were exposed to effluent volume ratio (EVR, ratio of effluent volume accounted for tailwater seawater mixture) 0%, 1%, 5%, 10%, and 20% (v/v) TME for 15 days and the following biochemical responses in gills were measured: (1) the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione (GSH) content, and lipid peroxidation levels of malondialdehyde (MDA), as oxidative stress biomarkers; (2) the activity of 7-ethoxyresorufin O-deethylase (EROD) and gluthathione S-transferase (GST), as phase I and phase II conjugation enzymes, respectively; (3) acetylcholinesterase (AChE), as a biomarker of neurotoxicity, and (4) metallothioneins (MTs), as proteins strongly induced by heavy metals. Most of the biochemical indices present high and significant variation frequency (above 50%). There is enhancement in the antioxidant enzymes, EROD, GST, AChE, and MTs, as well as consumption of GSH. The current experimental results suggest that effluent with concentrations less than 20% (v/v) do not cause lipid peroxidation damage. This implies that the activated defense is sufficient to protect the bivalves' gill tissues from cytotoxicity produced by the effluent. Furthermore, GSH, GPx, MTs, and GR are suitable, and sufficiently sensitive, biomarkers to indicate the pollution levels in marine environments receiving such effluent. PMID:25450918

  3. Exposure to phenanthrene and depuration: Changes on gene transcription, enzymatic activity and lipid peroxidation in gill of scallops Nodipecten nodosus.

    PubMed

    Piazza, Rômi S; Trevisan, Rafael; Flores-Nunes, Fabrício; Toledo-Silva, Guilherme; Wendt, Nestor; Mattos, Jacó J; Lima, Daína; Taniguchi, Satie; Sasaki, Silvio Tarou; Mello, Álvaro C P; Zacchi, Flávia L; Serrano, Miguel A S; Gomes, Carlos H A M; Bícego, Márcia C; Almeida, Eduardo A de; Bainy, Afonso C D

    2016-08-01

    Understanding the mechanism of phenanthrene (PHE) biotransformation and related cellular responses in bivalves can be an important tool to elucidate the risks of polycyclic aromatic hydrocarbons (PAHs) to aquatic organisms. In the present study it was analyzed the transcriptional levels of 13 biotransformation genes related to cytochrome P450 (CYP), glutathione S-transferase (GST), sulfotransferase (SULT), flavin-containing monooxygenase and fatty acid-binding proteins by qPCR in gill of scallops Nodipecten nodosus exposed for 24 or 96h to 50 or 200μgL(-1) PHE (equivalent to 0.28 and 1.12μM, respectively), followed by depuration in clean water for 96h (DEP). Likewise, it was quantified the activity of catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD), glutathione reductase (GR), glucose 6-phosphate dehydrogenase (G6PDH), GST and levels of lipid peroxidation. Increased transcriptional levels of CYP2UI-like, CYP2D20-like, CYP3A11-like, GSTomega-like, SULT1B1-like genes were detected in organisms exposed to PHE for 24 or 96h. In parallel, GR and GPX activities increased after 96h exposure to 200μgL(-1) PHE and G6PDH activity increased after 24h exposure to 50μgL(-1) PHE. This enhancement of antioxidant and phase I and II biotransformation systems may be related to the 2.7 and 12.5 fold increases in PHE bioaccumulation after 96h exposure to 50 and 200μgL(-1) PHE, respectively. Interestingly, DEP caused reestablishment of GPX and GR activity, as well as to the transcript levels of all upregulated biotransformation genes (except for SULT1B1-like). Bioaccumulated PHE levels decreased 2.5-2.9 fold after depuration, although some biochemical and molecular modifications were still present. Lipid peroxidation levels remained lower in animals exposed to 200μgL(-1) PHE for 24h and DEP. These data indicate that N. nodosus is able to induce an antioxidant and biotransformation-related response to PHE exposure, counteracting its toxicity, and DEP can

  4. Eroding Lava Flows

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    Today's image illustrates how radically the wind can affect the surface of Mars. The lava flows in this region have been covered by fine materials, and eroded by the sand blasting action of the wind. In this region the winds are blowing to the west, eroding the lava surface to form small east/west ridges and bumps. Given enough time the winds will change the appearance of the surface to such a large extent that all flow features will be erased.

    Image information: VIS instrument. Latitude -11.7, Longitude 220 East (140 West). 17 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  5. FXYD11 mediated modulation of Na(+)/K(+)-ATPase activity in gills of the brackish medaka (Oryzias dancena) when transferred to hypoosmotic or hyperosmotic environments.

    PubMed

    Chang, Chia-Hao; Yang, Wen-Kai; Lin, Chia-Hao; Kang, Chao-Kai; Tang, Cheng-Hao; Lee, Tsung-Han

    2016-04-01

    FXYD proteins regulate Na(+)/K(+)-ATPase (NKA), which is a primary active pump that provides the driving force that triggers osmoregulatory systems in teleosts. To explore the regulatory mechanisms between FXYD and NKA in euryhaline teleosts, the expression of NKA (mRNA, protein, and activity) and FXYD11 and their interaction were examined in the gills of brackish medaka (Oryzias dancena) when transferred from brackish water (BW; 15‰) to fresh water (FW) or seawater (SW; 35‰). The mRNA expression of Odfxyd11 and Odnka-α was elevated 48h post-hypoosmotic transfer. Moreover, FXYD11 protein and NKA activity were upregulated 12h after transfer to FW. When transferred to SW, the protein abundance of FXYD11 and the NKA α-subunit did not show apparent changes, while Odfxyd11 and Odnka-α mRNA expression and NKA activity increased significantly 12h and 1h post-transfer, respectively. To clarify the FXYD11 mechanisms involved in modulating NKA activity via their interaction, co-immunoprecipitation was further applied to O. dancena gills. The results revealed that the levels of protein-protein interaction between branchial NKA and FXYD11 increased acutely 12h after the transfer from BW to FW. However, immediate upregulation of NKA activity 1h following post-exposure to SW, without the elevation of protein-protein interaction levels, was found. Hence, branchial NKA activity of O. dancena was suggested to be rapidly regulated by FXYD11 interaction with NKA when acclimated to hypoosmotic environments. To the best of our knowledge, this is the first study that focuses on the efficacy of interactions between FXYD11 and NKA in the gills of euryhaline teleosts. PMID:26797570

  6. Ionic regulation and Na(+)-K(+)-ATPase activity in gills and kidney of the freshwater stingray Paratrygon aiereba living in white and blackwaters in the Amazon Basin.

    PubMed

    Duncan, W P; Costa, O T F; Araújo, M L G; Fernandes, M N

    2009-03-01

    During low-water period, freshwater stingray Paratrygon aiereba collected in the whitewater (WW) of the River Amazon showed higher urea content, osmolality, Na(+) and Cl(-) concentrations in plasma and perivisceral fluid than those caught in blackwater (BW) of the River Negro. Gills and kidney Na(+)-K(+)-ATPase activities were significantly lower in WW than in BW fish. The high level of kidney Na(+)-K(+)-ATPase activity in P. aiereba may minimize ion loss and generate diluted solute-free urine in ion-poor BW environment. PMID:20735610

  7. Effects of exposure to oxamyl, carbofuran, dichlorvos, and lindane on acetylcholinesterase activity in the gills of the Pacific oyster Crassostrea gigas.

    PubMed

    Anguiano, Gerardo A; Amador, Alejandro; Moreno-Legorreta, Manuel; Arcos-Ortega, Fabiola; Vazquez-Boucard, Celia

    2010-08-01

    Acetylcholinesterase (AChE) activity has been used to test the exposure of mollusk bivalves to pesticides and other pollutants. The Pacific oyster Crassostrea gigas is a species with a worldwide distribution, and it has a high commercial value. The use of this species as a bioindicator in the marine environment, and the use of measurements of AChE activity in tissues of C. gigas require prior evaluation of organisms exposed to several toxic compounds in the laboratory. In our study, the effects of pesticides on AChE activity in the gills and mantle tissues of C. gigas were analyzed by exposing animals to organophosphate (dichlorvos), carbamate (carbofuran and oxamyl), and organochlorine (lindane) pesticides. Adult Pacific oysters were exposed to several concentrations (0.1-200 microM) of dichlorvos, carbofuran, and oxamyl for 96 h, and lindane (1.0 and 2.5 microM) was applied for 12 days. In gill tissues, all pesticides analyzed caused a decrease in AChE activity when compared to the control unexposed group. The mean inhibition concentration (IC(50)) values were determined for dichlorvos, carbofuran, and oxamyl pesticides. Dichlorvos had the highest toxic effect, with an IC(50) of 1.08 microM; lesser effects were caused by oxamyl and carbofuran, with IC(50)s of 1.67 and 3.03 microM, respectively. This study reports the effects of pesticides with several chemical structures and validates measurement of AChE activity in the gill tissues of C. gigas for use in environmental evaluations or food quality tests. PMID:19449386

  8. Metals (Ag(+) , Cd(2+) , Cr(6+) ) affect ATPase activity in the gill, kidney, and muscle of freshwater fish Oreochromis niloticus following acute and chronic exposures.

    PubMed

    Atli, Gülüzar; Canli, Mustdafa

    2013-12-01

    Freshwater fish Oreochromis niloticus were individually acutely exposed to different concentrations (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) of Cd(2+) , Cr(6+) , and Ag(+) for 96 h and 0.05 μg/mL concentration of the same metals for different periods (0, 5, 10, 20, and 30 days) chronically. Following each experimental protocol, Na(+) /K(+) -ATPase, Mg(2+) -ATPase, and Ca(2+) -ATPase activities were measured in the gill, kidney, and muscle of O. niloticus. In vitro experiments were also performed to determine the direct effects of metal ions (0, 0.1, 0.5, 1.0, and 1.5 μg/mL) on ATPases. Except Ag(+) , none of the metals caused fish mortality within 30 days. Silver killed all the fishes within 16 days. Metal exposures generally decreased Na(+) /K(+) -ATPase and Ca(2+) -ATPase activities in the tissues of O. niloticus, although there were some fluctuations in Mg(2+) -ATPase activity. Ag(+) and Cd(2+) were found to be more toxic to ATPase activities than Cr(6+) . It was also observed that metal efficiency was higher in the gill than in the other tissues. Results indicated that the response of ATPases varied depending on metals, exposure types, and tissues. Because ATPases are sensitive to metal toxicity, their activity can give valuable data about fish physiology. Therefore, they may be used as a sensitive biomarker in environmental monitoring in contaminated waters. PMID:21901811

  9. Gill's 'History' restored

    NASA Astrophysics Data System (ADS)

    Hurn, Mark

    2009-06-01

    Note about the restoration of the copy of Sir David Gill's 'A History and Description of the Royal Observatory, Cape of Good Hope' in the Library of the Institute of Astronomy, Cambridge. The book was restored with funds provided by the SHA in thanks for facilities for meetings provided to the Institute.

  10. Ethoxyresorufin-O-deethylase (EROD) activity modulation of 2,3,7,8-tetrachlorodibenzo-p-dioxin and 3,3',4,4',5-pentachlorobiphenyl (PCB 126) in the presence of aqueous suspensions of nano-C60.

    PubMed

    Rathore, Rajesh; Schramm, Karl-Werner

    2014-03-01

    The increase in commercial production and inevitable release of fullerenes into the environment accelerates concerns about their potential toxicity. Furthermore, the concomitant release of xenobiotics poses a health hazard to humans, and might present potential long-term risks to human health. In the present study, we found that an aqueous suspension of buckminsterfullerene (aqu-nC60) does not result in the induction of ethoxyresorufin-O-deethylase (EROD) activity in H4IIE rat liver cells in vitro. The simultaneous and sequential exposure of aqu-nC60 and the dioxin TCDD induces EROD activity to the same extent as TCDD alone (i.e. in the absence of fullerene), in spite of the high affinity of C60 for TCDD. However, the co-exposure of aqu-nC60 and PCB 126 induces elevated EROD activity, and sequential exposure increases responses 2-fold compared to the control samples. Our in vitro observations suggest a potential source of drug-drug type interaction of fullerene with xenobiotics, particularly after a sequential exposure. PMID:24773490

  11. Survey of receiving-water environmental impacts associated with discharges from pulp mills; 2: Gonad size, liver size, hepatic erod activity and plasma sex steroid levels in white sucker

    SciTech Connect

    Munkittrick, K.R.; Servos, M.R. . Great Lakes Lab. for Fisheries and Aquatic Sciences); Van Der Kraak, G.J.; McMaster, M.E. . Dept. of Zoology); Portt, C.B. ); Heuvel, M.R. van den . Dept. of Biology)

    1994-07-01

    Fish collected from the receiving areas of 12 Canadian pulp mills were examined, including sites receiving effluent from kraft mills using chlorine as well as sulfite mills. Field collections included sampling of receiving water for chemistry and toxicity testing, and sampling of local fish for organ weights, hepatic MFO (ethoxyresorufin-O-deethylase, EROD) activity, plasma steroid levels, and levels of liver dioxins. The main objectives of this study were to determine whether the discharge of effluent from pulp mills to sites other than Jackfish Bay was associated with physiological or biochemical disruptions in wild fish, whether there was any correlation between waste treatment and the presence of biological responses in wild fish, and whether there was any association between the use of chlorine as a bleaching agent and these responses. Although white sucker collected near bleached-kraft mills exhibited the highest EROD induction and dioxin levels, elevated enzyme activity was observed in fish from sites that did not use chlorine, and depressions in plasma sex steroid levels was not correlated with the level of EROD activity. The absence of chlorine bleaching or the presence of secondary treatment did not eliminate responses in fish, including decreased circulating levels of sex steroids, decreased gonadal size, and increase liver size. This survey has shown that (a) induction of hepatic EROD enzymes and depressions of plasma sex steroid levels during gonadal growth are found downstream of several pulp mills; (b) these changes are seen at some mills without chlorine bleaching and at mills that have secondary treatment; (c) substantial dilutions of nontoxic effluent do not appear to remove these responses; (d) the dominant factor determining the presence or absence of responses appeared to be dilution level; and (e) lab toxicity tests on invertebrates, rainbow trout, and fat-head minnows could not predict the presence of these responses in wild fish.

  12. Acute toxicity of carbamazepine to juvenile rainbow trout (Oncorhynchus mykiss): effects on antioxidant responses, hematological parameters and hepatic EROD.

    PubMed

    Li, Zhi-Hua; Zlabek, Vladimir; Velisek, Josef; Grabic, Roman; Machova, Jana; Kolarova, Jitka; Li, Ping; Randak, Tomas

    2011-03-01

    Awareness of residual pharmaceutically active compounds (PhACs) in the aquatic environment is growing as investigations into these pollutants are increasing and analytical detection techniques are improving. However, the toxicological effects of PhACs have not been adequately researched. In this study, the toxic effects of carbamazepine (CBZ), an anticonvulsant drug commonly present in surface and groundwater, was studied in juvenile rainbow trout, Oncorhynchus mykiss, by acute semi-static bioassay. Blood parameters, liver xenobiotic-metabolizing response and tissue antioxidant status were evaluated. Compared to the control group, fish exposed to CBZ (96 h LC50) showed significantly higher Er, Hb, MCHC, monocytes, neutrophil granulocytes and plasma enzymes activity, and significantly lower MCV and lymphocytes. CF and HSI were not significantly different among groups such as hepatic EROD. SOD, CAT, GPx and GR activity was significantly higher in liver of experimental groups, but decreased significantly in brain and gill. In general, antioxidant enzyme activity in intestine and muscle was less evident than in liver. Oxidative stress indices (levels of LPO and CP) were significantly higher in gill and brain, despite a trend to increased values were manifested in the remaining tissues. In short, CBZ-induced stress responses in different tissues were reflected in the oxidant stress indices and hematological parameters. However, before those parameters are used as special biomarkers for monitoring residual pharmaceuticals in aquatic environment, more detailed experiments in laboratory need to be performed in the future. PMID:20971511

  13. Erodibility characteristics of embankment materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Erosion is one of the least reliably defined elements of many hydraulic projects. Earthen embankments (i.e. dams and levees) are an example of hydraulic projects in which erosion and material erodibility have not been reliably defined in the past. Recent as well as past embankment failures have he...

  14. Use of a combined effect model approach for discriminating between ABCB1- and ABCC1-type efflux activities in native bivalve gill tissue.

    PubMed

    Faria, Melissa; Pavlichenko, Vasiliy; Burkhardt-Medicke, Kathleen; Soares, Amadeu M V M; Altenburger, Rolf; Barata, Carlos; Luckenbach, Till

    2016-04-15

    Aquatic organisms, such as bivalves, employ ATP binding cassette (ABC) transporters for efflux of potentially toxic chemicals. Anthropogenic water contaminants can, as chemosensitizers, disrupt efflux transporter function enabling other, putatively toxic compounds to enter the organism. Applying rapid amplification of cDNA ends (RACE) PCR we identified complete cDNAs encoding ABCB1- and ABCC1-type transporter homologs from zebra mussel providing the molecular basis for expression of both transporter types in zebra mussel gills. Further, efflux activities of both transporter types in gills were indicated with dye accumulation assays where efflux of the dye calcein-am was sensitive to both ABCB1- (reversin 205, verapamil) and ABCC1- (MK571) type specific inhibitors. The assumption that different inhibitors targeted different efflux pump types was confirmed when comparing measured effects of binary inhibitor compound mixtures in dye accumulation assays with predictions from mixture effect models. Effects by the MK571/reversin 205 mixture corresponded better with independent action, whereas reversin 205/verapamil joint effects were better predicted by the concentration addition model indicating different and equal targets, respectively. The binary mixture approach was further applied to identify the efflux pump type targeted by environmentally relevant chemosensitizing compounds. Pentachlorophenol and musk ketone, which were selected after a pre-screen of twelve compounds that previously had been identified as chemosensitizers, showed mixture effects that corresponded better with concentration addition when combined with reversine 205 but with independent action predictions when combined with MK571 indicating targeting of an ABCB1-type efflux pump by these compounds. PMID:26929997

  15. A kinetic characterization of (Na+, K+)-ATPase activity in the gills of the pelagic seabob shrimp Xiphopenaeus kroyeri (Decapoda, Penaeidae).

    PubMed

    Leone, Francisco Assis; Lucena, Malson Neilson; Rezende, Luciana Augusto; Garçon, Daniela Pereira; Pinto, Marcelo Rodrigues; Mantelatto, Fernando Luis; McNamara, John Campbell

    2015-04-01

    We characterize the kinetic properties of a gill (Na(+), K(+))-ATPase from the pelagic marine seabob Xiphopenaeus kroyeri. Sucrose density gradient centrifugation revealed membrane fractions distributed mainly into a heavy fraction showing considerable (Na(+), K(+))-ATPase activity, but also containing mitochondrial F0F1- and Na(+)- and V-ATPases. Western blot analysis identified a single immunoreactive band against the (Na(+), K(+))-ATPase α-subunit with an Mr of ≈ 110 kDa. The α-subunit was immunolocalized to the intralamellar septum of the gill lamellae. The (Na(+), K(+))-ATPase hydrolyzed ATP obeying Michaelis-Menten kinetics with VM = 109.5 ± 3.2 nmol Pi min(-1) mg(-1) and KM = 0.03 ± 0.003 mmol L(-1). Mg(2+) (VM = 109.8 ± 2.1 nmol Pi min(-1 )mg(-1), K0.5 = 0.60 ± 0.03 mmol L(-1)), Na(+) (VM = 117.6 ± 3.5 nmol Pi min(-1 ) mg(-1), K0.5 = 5.36 ± 0.14 mmol L(-1)), K(+) (VM = 112.9 ± 1.4 nmol Pi min(-1 )mg(-1), K0.5 = 1.32 ± 0.08 mmol L(-1)), and NH4 (+) (VM = 200.8 ± 7.1 nmol Pi min(-1 )mg(-1), K0.5 = 2.70 ± 0.04 mmol L(-1)) stimulated (Na(+), K(+))-ATPase activity following site-site interactions. K(+) plus NH4 (+) does not synergistically stimulate (Na(+), K(+))-ATPase activity, although each ion modulates affinity of the other. The enzyme exhibits a single site for K(+) binding that can be occupied by NH4 (+), stimulating the enzyme. Ouabain (KI = 84.0 ± 2.1 µmol L(-1)) and orthovanadate (KI = 0.157 ± 0.001 µmol L(-1)) inhibited total ATPase activity by ≈ 50 and ≈ 44 %, respectively. Ouabain inhibition increases ≈ 80 % in the presence of NH4 (+) with a threefold lower KI, suggesting that NH4 (+) is likely transported as a K(+) congener. PMID:25534346

  16. Effects of individual and a mixture of pharmaceuticals and personal-care products on cytotoxicity, EROD activity and ROS production in a rainbow trout gonadal cell line (RTG-2).

    PubMed

    Fernández, Carlos; Carbonell, Gregoria; Babín, Mar

    2013-11-01

    The presence of pharmaceuticals and personal-care products (PPCPs) in aquatic environments is of concern. Although measured concentrations of individual substances are low, little consideration has been given to the likely chronic nature of the exposures or to the potential for mixture effects. The purpose of the present study was to use the RTG-2 rainbow trout cell line to analyse sub-lethal and cytotoxic effects of PPCPs present in a wastewater-treatment-plant (WWTP) effluents and their mixtures. Interactions with cytochrome P450 1A enzyme, oxidative stress, cellular senescence and cell viability were assessed using 7-ethoxyresorufin-o-deethylase (EROD), reactive oxygen species (ROS), ß-galactosidase (ß-gal) and neutral red (NR) uptake assays, respectively. Not all of the compounds that were tested exhibited significant effects. The lowest-observed-effect concentrations and half maximal effective concentrations (EC50 ) were within the range 0.15 to 784.47 µg l(-1) . Clear dose-response curves were found for cells exposed to different mixtures of PPCPs. The lowest-observed-effect concentrations and concentrations causing EC50 were within the range 0.05 to 54.61 µg l(-1) . Four out the seven tested mixtures induced EROD activity. ROS production was detected in two mixtures. The ß-gal inhibition response was observed in six out the seven tested mixtures and occurred at a higher concentration than was observed for EROD induction activity or ROS generation. The present study clearly shows that the stress response through which cells mount a homeostatic response to toxicants can be potentially used for an initial, rapid and cost-effective assessment of the complex mixtures of PPCP that present in WWTP effluents are difficult and expensive to analyse chemically. PMID:22718253

  17. Ecological risk assessment of silicon dioxide nanoparticles in a freshwater fish Labeo rohita: Hematology, ionoregulation and gill Na(+)/K(+) ATPase activity.

    PubMed

    Krishna Priya, K; Ramesh, M; Saravanan, M; Ponpandian, N

    2015-10-01

    The fate and effect of nanomaterials in the environment has raised concern about their environmental risk to aquatic organisms. Silica nanoparticles (SiO2-NPs) find its uses in various fields and are inevitably released into the environment. However, the ecotoxicological effects of SiO2-NPs on the freshwater fish remain poorly understood. The aim of this study was to evaluate the effect of different concentrations (1, 5 and 25mgL(-1)) of SiO2-NPs on certain hematological, ionoregulatory and enzymological profiles of a freshwater teleost fish Labeo rohita. Hematological parameters such as hemoglobin (Hb), hematocrit (Hct), red blood cells (RBC), white blood cells (WBC), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) values were altered in SiO2-NPs treated groups. Likewise, plasma electrolytes such as plasma sodium (Na(+)), potassium (K(+)) and chloride (Cl(-)) levels and Na(+)/K(+) ATPase activity in gill of SiO2-NPs treated groups were altered in all concentrations throughout the study period (96h). The alterations of these parameters were found to be dependent on dose and exposure period. The results of the present study indicate that the alterations of these parameters may relate to physiological stress system to SiO2-NPs toxicity and also demonstrate that manufactured metal oxide NPs in aquatic environment may affect the health condition of the aquatic organisms. PMID:26094035

  18. Resprout and Survival of Willow ( Salix) Cuttings on Bioengineering Structures in Actively Eroding Gullies in Marls in a Mountainous Mediterranean Climate: A Large-Scale Experiment in the Francon Catchment (Southern Alps, France)

    NASA Astrophysics Data System (ADS)

    Rey, F.; Labonne, S.

    2015-10-01

    Improving the understanding of the role of vegetation and bioengineering structures on erosion and sedimentation control, especially in torrent-prone catchments in a mountainous Mediterranean climate, has become a key issue today for the scientific community working in ecological engineering and restoration ecology. The objective of this study was to evaluate the performance of willow ( Salix) cuttings in resprouting and survival on bioengineering structures in actively eroding gullies in marls and to identify the factors influencing this performance. Measurements were taken from 2008 to 2011 on 336 bioengineering structures, namely brush layers on wooden sills (BL) and brush layers with brush mats on wooden sills (BLM), using 8890 cuttings of Salix purpurea and Salix incana. These structures were built in 18 gullies of the Francon Catchment in marls (73 ha) in the Southern French Alps. After four growing seasons, the results revealed a total cutting survival rate of 45 %. They also demonstrated that in BLM, brush mats provided better survival (56 %) than brush layers (37 %). In BL, brush layers alone showed 51 % cutting survival. Cutting resprout and survival were observed for all structure aspects. They were positively related to increasing gully size and vegetation cover on gully sides. The results of this large-scale experiment clarified previous data obtained on a limited sample of bioengineering structures, providing further detail and showing that it is possible to use such structures made of willow cuttings to revegetate actively eroding gullies in marls within a mountainous Mediterranean climate.

  19. Neuroepithelial oxygen chemoreceptors of the zebrafish gill

    PubMed Central

    Jonz, Michael G; Fearon, Ian M; Nurse, Colin A

    2004-01-01

    In aquatic vertebrates, hypoxia induces physiological changes that arise principally from O2 chemoreceptors of the gill. Neuroepithelial cells (NECs) of the zebrafish gill are morphologically similar to mammalian O2 chemoreceptors (e.g. carotid body), suggesting that they may play a role in initiating the hypoxia response in fish. We describe morphological changes of zebrafish gill NECs following in vivo exposure to chronic hypoxia, and characterize the cellular mechanisms of O2 sensing in isolated NECs using patch-clamp electrophysiology. Confocal immunofluorescence studies indicated that chronic hypoxia (PO2 = 35 mmHg, 60 days) induced hypertrophy, proliferation and process extension in NECs immunoreactive for serotonin or synaptic vesicle protein (SV2). Under voltage clamp, NECs responded to hypoxia (PO2 = 25–140 mmHg) with a dose-dependent decrease in K+ current. The current–voltage relationship of the O2-sensitive current (IKO2) reversed near EK and displayed open rectification. Pharmacological characterization indicated that IKO2 was resistant to 20 mm tetraethylammonium (TEA) and 5 mm 4-aminopyridine (4-AP), but was sensitive to 1 mm quinidine. In current-clamp recordings, hypoxia produced membrane depolarization associated with a conductance decrease; this depolarization was blocked by quinidine, but was insensitive to TEA and 4-AP. These biophysical and pharmacological characteristics suggest that hypoxia sensing in zebrafish gill NECs is mediated by inhibition of a background K+ conductance, which generates a receptor potential necessary for neurosecretion and activation of sensory pathways in the gill. This appears to be a fundamental mechanism of O2 sensing that arose early in vertebrate evolution, and was adopted later in mammalian O2 chemoreceptors. PMID:15331683

  20. Gill morphometrics of the thresher sharks (Genus Alopias): Correlation of gill dimensions with aerobic demand and environmental oxygen.

    PubMed

    Wootton, Thomas P; Sepulveda, Chugey A; Wegner, Nicholas C

    2015-05-01

    Gill morphometrics of the three thresher shark species (genus Alopias) were determined to examine how metabolism and habitat correlate with respiratory specialization for increased gas exchange. Thresher sharks have large gill surface areas, short water-blood barrier distances, and thin lamellae. Their large gill areas are derived from long total filament lengths and large lamellae, a morphometric configuration documented for other active elasmobranchs (i.e., lamnid sharks, Lamnidae) that augments respiratory surface area while limiting increases in branchial resistance to ventilatory flow. The bigeye thresher, Alopias superciliosus, which can experience prolonged exposure to hypoxia during diel vertical migrations, has the largest gill surface area documented for any elasmobranch species studied to date. The pelagic thresher shark, A. pelagicus, a warm-water epi-pelagic species, has a gill surface area comparable to that of the common thresher shark, A. vulpinus, despite the latter's expected higher aerobic requirements associated with regional endothermy. In addition, A. vulpinus has a significantly longer water-blood barrier distance than A. pelagicus and A. superciliosus, which likely reflects its cold, well-oxygenated habitat relative to the two other Alopias species. In fast-swimming fishes (such as A. vulpinus and A. pelagicus) cranial streamlining may impose morphological constraints on gill size. However, such constraints may be relaxed in hypoxia-dwelling species (such as A. superciliosus) that are likely less dependent on streamlining and can therefore accommodate larger branchial chambers and gills. PMID:25703507

  1. Low-Temperature Biochar Affects an Eroded Calcareous Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research showed little benefit from using a high temperature, high pH biochar for improving the fertility of eroded calcareous soils. We thus explored the potential of an activated, low-temperature, low pH biochar to improve their fertility status. In a microcosm study conducted at 20 de...

  2. Are we missing a mineralocorticoid in teleost fish? Effects of cortisol, deoxycorticosterone and aldosterone on osmoregulation, gill Na+,K+-ATPase activity and isoform mRNA levels in Atlantic salmon

    USGS Publications Warehouse

    McCormick, S.D.; Regish, A.; O'Dea, M. F.; Shrimpton, J.M.

    2008-01-01

    It has long been held that cortisol, acting through a single receptor, carries out both glucocorticoid and mineralocorticoid actions in teleost fish. The recent finding that fish express a gene with high sequence similarity to the mammalian mineralocorticoid receptor (MR) suggests the possibility that a hormone other than cortisol carries out some mineralocorticoid functions in fish. To test for this possibility, we examined the effect of in vivo cortisol, 11-deoxycorticosterone (DOC) and aldosterone on salinity tolerance, gill Na+,K+-ATPase (NKA) activity and mRNA levels of NKA α1a and α1b in Atlantic salmon. Cortisol treatment for 6–14 days resulted in increased, physiological levels of cortisol, increased gill NKA activity and improved salinity tolerance (lower plasma chloride after a 24 h seawater challenge), whereas DOC and aldosterone had no effect on either NKA activity or salinity tolerance. NKA α1a and α1b mRNA levels, which increase in response to fresh water and seawater acclimation, respectively, were both upregulated by cortisol, whereas DOC and aldosterone were without effect. Cortisol, DOC and aldosterone had no effect on gill glucocorticoid receptor GR1, GR2 and MR mRNA levels, although there was some indication of possible upregulation of GR1 by cortisol (p = 0.07). The putative GR blocker RU486 inhibited cortisol-induced increases in salinity tolerance, NKA activity and NKA α1a and α1b transcription, whereas the putative MR blocker spironolactone had no effect. The results provide support that cortisol, and not DOC or aldosterone, is involved in regulating the mineralocorticoid functions of ion uptake and salt secretion in teleost fish.

  3. Synergistic stimulation by potassium and ammonium of K(+)-phosphatase activity in gill microsomes from the crab Callinectes ornatus acclimated to low salinity: novel property of a primordial pump.

    PubMed

    Garçon, Daniela P; Lucena, Malson N; Pinto, Marcelo R; Fontes, Carlos F L; McNamara, John C; Leone, Francisco A

    2013-02-15

    We provide an extensive characterization of the modulation by p-nitrophenylphosphate, Mg²⁺, Na⁺, K(+), Rb⁺, NH(4)(+) and pH of gill microsomal K⁺-phosphatase activity in the posterior gills of Callinectes ornatus acclimated to low salinity (21‰). The synergistic stimulation by K⁺ and NH(4)(+) of the K⁺-phosphatase activity is a novel finding, and may constitute a species-specific feature of K(+)/NH(4)(+) interplay that regulates crustacean gill (Na⁺, K⁺)-ATPase activity. p-Nitrophenylphosphate was hydrolyzed at a maximum rate (V) of 69.2 ± 2.8nmolPimin⁻¹mg⁻¹ with K(0.5)=2.3 ± 0.1mmolL(-1), obeying cooperative kinetics (n(H)=1.7). Stimulation by Mg²⁺ (V=70.1 ± 3.0nmolPimin⁻¹mg⁻¹, K(0.5)=0.88 ± 0.04mmolL⁻¹), K⁺ (V=69.6 ± 2.7nmolPimin⁻¹mg⁻¹, K(0.5)=1.60 ± 0.07mmolL⁻¹) and NH(4)(+) (V=90.8 ± 4.0nmolPimin⁻¹mg⁻¹, K(0.5)=9.2 ± 0.3mmol L⁻¹) all displayed site-site interaction kinetics. In the presence of NH(4)(+), enzyme affinity for K⁺ unexpectedly increased by 7-fold, while affinity for NH(4)(+) was 28-fold greater in the presence than absence of K⁺. Ouabain partially inhibited K⁺-phosphatase activity (K(I)=320 ± 14.0μmolL⁻¹), more effectively when NH(4)(+) was present (K(I)=240 ± 12.0μmolL⁻¹). We propose a model for the synergistic stimulation by K⁺ and NH(4)(+) of the K⁺-phosphatase activity of the (Na⁺, K⁺)-ATPase from C. ornatus posterior gill tissue. PMID:23262318

  4. Characterization and Purification of Glutathione S-Transferase from the Liver and Gill Tissues of Ağrı Balık Lake Trout Salmo trutta labrax and the Effects of Heavy Metal Ions on Its Activity.

    PubMed

    Çomaklı, Veysel; Kuzu, Muslum; Demirdağ, Ramazan

    2015-09-01

    Glutathione S-transferase (GST) from the liver and gill tissues of Ağrı Balık Lake Trout (also known as Black Sea Trout) Salmo trutta labrax was characterized and purified, and the toxic effects of some heavy metal ions on the enzyme's activity were analyzed. Liver GST was purified 930 times, resulting in 56% yield using glutathione-agarose affinity chromatography and a specific activity of 60.87 endotoxin units (EU)/mg protein. Using the same procedure, gill GST was purified 576 times, resulting in a 60% yield and specific activity of 46.8 EU/mg protein. The purity check of the purified enzymes was determined with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Optimal pH, ionic strength, and stable pH were found for each tissue, and separate KM and Vmax values were determined for reduced glutathione and 2,4-dinitrochlorobenzene substrates. Heavy metal ions that have toxic effects on living organisms and are known to contribute to environmental pollution were selected, and their in vitro effects on enzyme activity were analyzed. The IC50 values and Ki constants of those metal ions showing an inhibitory effect on GST activity were determined. PMID:26075414

  5. Main features of the oxidative metabolism in gills and liver of Odontesthes nigricans Richardson (Pisces, Atherinopsidae).

    PubMed

    Lattuca, M E; Malanga, G; Aguilar Hurtado, C; Pérez, A F; Calvo, J; Puntarulo, S

    2009-12-01

    The aim of this work was to study comparatively the oxidative metabolism in gills and liver of a silverside, Odontesthes nigricans, in their natural environment, the Beagle Channel. Oxidative damage to lipids was evaluated by assessing TBARS and lipid radical content, in gills and liver. Gills showed a significantly higher degree of damage than liver. The content of alpha-tocopherol, beta-carotene and catalase activity showed significantly higher values in the liver than in the gills. The ascorbyl radical (A(*)) content showed no significant differences between gills and liver. The ascorbate (AH(-)) content was 12+/-2 and 159+/-28 nmol/mg FW in gills and liver, respectively. Oxidative metabolism at the hydrophilic level was assessed as the ratio A(*)/AH(-). The ratio A(*)/AH(-) was significantly different between organs, (6+/-2)10(-5) and (5+/-2)10(-6), for the gills and the liver, respectively. Both, lipid radical content/alpha-tocopherol content and lipid radical content/beta-carotene content ratios were significantly higher in gills as compared to the values recorded for the liver, suggesting an increased situation of oxidative stress condition in the lipid phase of the gills. Taken as a whole, the O. nigricans liver exhibited a better control of oxidative damage than the gills, allowing minimization of intracellular damage when exposed to environmental stressing conditions. PMID:19706336

  6. Morphology and ventilatory function of gills in the carpet shark family Parascylliidae (Elasmobranchii, Orectolobiformes).

    PubMed

    Goto, Tomoaki; Shiba, Yojiro; Shibagaki, Kazuhiro; Nakaya, Kazuhiro

    2013-06-01

    We examined gill morphology and ventilatory function in the carpet shark family Parascylliidae using 14 preserved specimens of Parascyllium ferrugineum, P. variolatum, P. collare and Cirrhoscyllium japonicum, and two live specimens of P. ferrugineum and P. variolatum. Morphological examinations revealed eight morphological characteristics related to the fifth gill, based on comparisons with other elasmobranchs, viz. large fifth gill slit without gill filaments, anatomical modifications in the fourth ceratobranchial cartilage and coraco-branchialis muscle, and the hypaxialis muscle associated with the fifth gill arch. Ventilation examinations using dyed seawater and prey items showed different water flows through the gill slits for respiration and prey-capture actions. For respiration, water sucked into the mouth was expelled equally through the first to fourth gill slits via a "double-pump" action, there being no involvement of the fifth gill slit. In prey-capture, however, water sucked into the mouth was discharged only via the widely opened fifth gill slit. This form of water flow is similar to that in other benthic suction-feeding sharks (e.g., Chiloscyllium plagiosum), except for the active water discharge by wide expansion and contraction of the fifth parabranchial cavity. The latter is dependent upon the morphological modifications of the fourth and fifth gill arches, derived phylogenetically as a mechanistic suction specialization in Parascylliidae. PMID:23721470

  7. Oxidative stress response in gill and liver of Liza saliens, from the Esmoriz-Paramos coastal lagoon, Portugal.

    PubMed

    Fernandes, C; Fontaínhas-Fernandes, A; Ferreira, M; Salgado, M A

    2008-08-01

    Tissue-specific responses against oxidative stress and lipid peroxidation were analyzed in wild adult mullet (Liza saliens) caught in the Portuguese coastal lagoon Esmoriz-Paramos. Parameters measured were catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST) activities in liver and gill tissues and lipid peroxidation. The enzyme activities were related to gill histopathological alterations, as well as to heavy metals (Cu and Zn) concentrations in these tissues. Gill epithelium of L. saliens showed histological alterations, such as epithelial hyperplasia resulting in lamellar fusion, epithelial lifting, vasodilatation, and lamellar aneurisms, with a prevalence ranging from 62% to 92%. The highest Cu content was found in liver (379 mg x kg(-1)), while the highest Zn content was observed in gill (119 mg x kg(-1)). SOD and CAT activities showed differences between gill and liver. The highest activities found were SOD in gill (10.1 U/mg protein) and CAT in liver (39.2 mmol/min/mg protein). In gill, CAT activity was negatively related to both Cu levels and gill lifting, while a positive relationship was found between SOD activity and fish age. The positive relationship between Cu and CAT activity in liver suggests that an increase in metabolic level is related to Cu-induced oxidative stress. The decrease in gill CAT activity can be due to osmotic stress caused by damaged gill epithelium. CAT activity in liver is an appropriate biomarker of oxidative stress in the Esmoriz-Paramos lagoon. PMID:18196193

  8. Leopard frog PCB levels and evaluation of EROD as a biomarker in Green Bay ecosystem

    SciTech Connect

    Huang, Y.W.; Karasov, W.H.; Patnode, K.P.

    1995-12-31

    The induction of mixed function oxidases has been shown to be a promising biomarker in many taxa of wildlife, though not yet tested for amphibians. The three hypotheses tested in this study were (1) activities of hepatic EROD of leopard frog (Rana pipiens) are induced following exposure to planar chlorinated PCBs, (2) tissue PCB residue levels of leopard frogs are positively correlated with their wetland sediment PCB levels, and (3) EROD activities are positively correlated with tissue PCB concentrations and sediment PCB. In the laboratory, EROD was increased 2--3 times seven days after i.p. injection with PCB 126 at doses {ge} 2.3 ppm (wet mass basis). Leopard frogs from seven sites along the Lower Fox River and Green Bay in 1994--1995 were assayed for hepatic EROD activities and total PCB levels in carcasses. Tissue PCB levels ranged from 3 to 152 ppb (including coplanar congeners) and were highest from sites with higher sediment PCB. EROD activity in frogs collected in August--September was not significantly correlated with frog body mass and was similar among sites with one exception. There was no significant correlation between EROD activity and tissue PCB concentration. This result was consistent with the fact that the frogs collected from the Green Bay ecosystem had relatively low PCB levels compared with what was required for induction in the laboratory. The authors conclude that EROD activity is not a sensitive biomarker of PCB exposure in leopard frogs in this ecosystem.

  9. A western type of bacterial gill disease

    USGS Publications Warehouse

    Fish, F.F.

    1935-01-01

    The first reference to a pathological condition of the gill tissues of salmonid fishes was made by Osburn in 1910. This author in describing a progressive infolding of the opercula of trout, commonly known to hatcherymen as "short gill covers," mentioned a marked proliferation on the gill epithelium as accompanying this condition. Osburn assumed that the club-like appearance of the gill filaments due to the proliferated epithelium was the result of continual irritation of the delicate gill tissue in the absence of the usual protection offered by the normal opercula. Although such a conclusion seems quite logical, it is also possible that Osburn was dealing with "short gill covers" complicated by the unknown bacterial gill disease which was subsequently described by Davis.

  10. Manure effects on soil N in eroded and non-eroded, sprinkler-irrigated soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Manure effects on nitrate-N transport through irrigated, low-organic matter calcareous soil are not well known. This field study quantified the effects of a one-time fall application of stockpiled dairy manure and urea on in-season and over-winter nitrate-N transport through non-eroded and eroded (...

  11. 7 CFR 12.22 - Highly erodible field determination criteria.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false Highly erodible field determination criteria. 12.22 Section 12.22 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.22 Highly erodible field determination criteria....

  12. 7 CFR 12.22 - Highly erodible field determination criteria.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Highly erodible field determination criteria. 12.22 Section 12.22 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.22 Highly erodible field determination criteria....

  13. 7 CFR 12.22 - Highly erodible field determination criteria.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false Highly erodible field determination criteria. 12.22 Section 12.22 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.22 Highly erodible field determination criteria....

  14. 7 CFR 12.22 - Highly erodible field determination criteria.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false Highly erodible field determination criteria. 12.22 Section 12.22 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.22 Highly erodible field determination criteria....

  15. 7 CFR 12.22 - Highly erodible field determination criteria.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false Highly erodible field determination criteria. 12.22 Section 12.22 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.22 Highly erodible field determination criteria....

  16. Soil erodibility evaluation under different management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erosion is a major factor leading to water quality degradation throughout the United States. Soil erosion involves particle detachment and transport, followed by deposition. The ability of water to detach and transport soil particles is known as the soil’s erodibility. Soil erosion is a resu...

  17. The Changing Mood in America. Eroding Commitment?

    ERIC Educational Resources Information Center

    Jones, Faustine Childress; And Others

    This book examines the current social climate in the United States to determine whether there is an eroding social commitment to equal opportunity for blacks and other minorities and the poor. It is concluded that there is a changing mood in the dominant society, in the black population, and in all three branches of the federal government, and it…

  18. Metolachlor dissipation in eroded and restored landscapes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In hilly landforms subject to long-term cultivation, erosion has denuded upper slope positions of topsoil and accumulated topsoil in lower slope positions. Landscape restoration is one approach to remediate these eroded landforms by moving soil from areas of topsoil accumulation to areas of topsoil ...

  19. Authority Grab Eroding Stature of State Boards

    ERIC Educational Resources Information Center

    McNeil, Michele

    2008-01-01

    This article reports on the eroding power of state school boards in the U.S. as lawmakers and governors are seeking to expand their authority over K-12 education and, in some cases, reverse education policy set in motion by elected or appointed panels. This year alone, state boards in Florida, Ohio, and Vermont are targets of legislation that…

  20. Purification of glucose-6-phosphate dehydrogenase and glutathione reductase enzymes from the gill tissue of Lake Van fish and analyzing the effects of some chalcone derivatives on enzyme activities.

    PubMed

    Kuzu, Muslum; Aslan, Abdulselam; Ahmed, Ishtiaq; Comakli, Veysel; Demirdag, Ramazan; Uzun, Naim

    2016-04-01

    Glucose-6-phosphate dehydrogenase (G6PD) and glutathione reductase (GR) are metabolically quite important enzymes. Within this study, these two enzymes were purified for the first time from the gills of Lake Van fish. In the purifying process, ammonium sulfate precipitation and 2',5'-ADP Sepharose 4B affinity column chromatography techniques for glucose-6-phosphate dehydrogenase, temperature degradation and 2',5'-ADP Sepharose 4B affinity column chromatography for glutathione reductase enzyme were used. The control of the enzyme purity and determination of molecular weight were done with sodium dodecyl sulfate polyacrylamide gel electrophoresis. K M and V max values were determined with Lineweaver-Burk plot. Besides, the effects of some chalcone derivatives on the purified enzymes were analyzed. For the ones showing inhibition effect, % activity-[I] figures were drawn and IC50 values were determined. K i value was calculated by using Cheng-Prusoff equation. PMID:26676512

  1. Optimal lamellar arrangement in fish gills

    PubMed Central

    Park, Keunhwan; Kim, Wonjung; Kim, Ho-Young

    2014-01-01

    Fish respire through gills, which have evolved to extract aqueous oxygen. Fish gills consist of filaments with well-ordered lamellar structures, which play a role in maximizing oxygen diffusion. It is interesting that when we anatomically observe the gills of various fish species, gill interlamellar distances (d) vary little among them, despite large variations in body mass (Mb). Noting that the small channels formed by densely packed lamellae cause significant viscous resistance to water flow, we construct and test a model of oxygen transfer rate as a function of the lamellar dimensions and pumping pressure, which allows us to predict the optimal interlamellar distance that maximizes the oxygen transfer rate in the gill. Comparing our theory with biological data supports the hypothesis that fish gills have evolved to form the optimal interlamellar distances for maximizing oxygen transfer. This explains the weak scaling dependence of d on Mb: d ∼ Mb1/6. PMID:24847065

  2. Morphological changes in the gills of Heteropneustes fossilis (Bloch) exposed to coal mining effluent water.

    PubMed

    Mylliemngap, B K; Ramanujam, S N

    2012-07-01

    Ultrastructural changes in the gills of cat fish Heteropneustes fossilis exposed to coal mining effluent water collected from Rymbai river in Jaintia hills, Meghalaya, India was investigated under scanning electron microscopy (SEM). The pH of effluent water in the river was significantly low (2.5-3.0) due to coal mining activity in the adjacent areas. The dissolved oxygen (DO) was 7.7 mg l(-1) and conductivity 0.93 mS. Morphological changes like dissociation of the epithelium (E) of branchial arches and gill filaments, hypertrophy and disorientation in the array of lamellae were observed in the treated fish, leading to fish death. The primary and secondary gill lamellae (PL and SL) exhibited fusion, distortion and loss of alignment. Some of the gill rackers showed necrosis at certain places. The morphological features of the gills as revealed through SEM were highly deteriorated when compared to control. PMID:23360000

  3. A shared role for sonic hedgehog signalling in patterning chondrichthyan gill arch appendages and tetrapod limbs.

    PubMed

    Gillis, J Andrew; Hall, Brian K

    2016-04-15

    Chondrichthyans (sharks, skates, rays and holocephalans) possess paired appendages that project laterally from their gill arches, known as branchial rays. This led Carl Gegenbaur to propose that paired fins (and hence tetrapod limbs) originally evolved via transformation of gill arches. Tetrapod limbs are patterned by asonic hedgehog(Shh)-expressing signalling centre known as the zone of polarising activity, which establishes the anteroposterior axis of the limb bud and maintains proliferative expansion of limb endoskeletal progenitors. Here, we use loss-of-function, label-retention and fate-mapping approaches in the little skate to demonstrate that Shh secretion from a signalling centre in the developing gill arches establishes gill arch anteroposterior polarity and maintains the proliferative expansion of branchial ray endoskeletal progenitor cells. These findings highlight striking parallels in the axial patterning mechanisms employed by chondrichthyan branchial rays and paired fins/limbs, and provide mechanistic insight into the anatomical foundation of Gegenbaur's gill arch hypothesis. PMID:27095494

  4. Morphodynamic modeling of erodible laminar channels

    NASA Astrophysics Data System (ADS)

    Devauchelle, Olivier; Josserand, Christophe; Lagrée, Pierre-Yves; Zaleski, Stéphane

    2007-11-01

    A two-dimensional model for the erosion generated by viscous free-surface flows, based on the shallow-water equations and the lubrication approximation, is presented. It has a family of self-similar solutions for straight erodible channels, with an aspect ratio that increases in time. It is also shown, through a simplified stability analysis, that a laminar river can generate various bar instabilities very similar to those observed in natural rivers. This theoretical similarity reflects the meandering and braiding tendencies of laminar rivers indicated by F. Métivier and P. Meunier [J. Hydrol. 27, 22 (2003)]. Finally, we propose a simple scenario for the transition between patterns observed in experimental erodible channels.

  5. Coupled length scales in eroding landscapes

    SciTech Connect

    Chan, Kelvin K.; Rothman, Daniel H.

    2001-05-01

    We report results from an empirical study of the anisotropic structure of eroding landscapes. By constructing a novel correlation function, we show quantitatively that small-scale channel-like features of landscapes are coupled to the large-scale structure of drainage basins. We show additionally that this two-scale interaction is scale-dependent. The latter observation suggests that a commonly applied effective equation for erosive transport may itself depend on scale.

  6. An interim report on gill disease

    USGS Publications Warehouse

    Rucker, R.R.; Johnson, H.E.; Kaydas, G.M.

    1952-01-01

    GILL DISEASE among fish, a disease which is characterized by a proliferation of the gill epithelium, has been attributed to a number of different causes. Generally, there are two recognized types: the eastern or bacterial type, in which long filamentous bacteria can always be demonstrated; and the western type, in which, by definition, bacteria cannot be demonstrated.

  7. Soil quality changes after topsoil addition to eroded land

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-landscape rehabilitation within eroded fields can be accomplished by moving topsoil from depositional to eroded landscape positions. The purpose is to improve soil quality and productivity of the upper root zone in eroded areas of the field. Changes in soil quality may be estimated through chan...

  8. Why mushrooms form gills: efficiency of the lamellate morphology

    PubMed Central

    FISCHER, Mark W. F.; MONEY, Nicholas P.

    2009-01-01

    Gilled mushrooms are produced by multiple orders within the Agaricomycetes. Some species form a single array of unbranched radial gills beneath their caps, many others produce multiple files of lamellulae between the primary gills, and branched gills are also common. In this largely theoretical study we modeled the effects of different gill arrangements on the total surface area for spore production. Relative to spore production over a flat surface, gills achieve a maximum 20-fold increase in surface area. The branching of gills produces the same increase in surface area as the formation of freestanding lamellulae (short gills). The addition of lamellulae between every second gill would offer a slightly greater increase in surface area in comparison to the addition of lamellulae between every pair of opposing gills, but this morphology does not appear in nature. Analysis of photographs of mushrooms demonstrates an excellent match between natural gill arrangements and configurations predicted by our model. PMID:20965062

  9. Why mushrooms form gills: efficiency of the lamellate morphology.

    PubMed

    Fischer, Mark W F; Money, Nicholas P

    2010-01-01

    Gilled mushrooms are produced by multiple orders within the Agaricomycetes. Some species form a single array of unbranched radial gills beneath their caps, many others produce multiple files of lamellulae between the primary gills, and branched gills are also common. In this largely theoretical study we modeled the effects of different gill arrangements on the total surface area for spore production. Relative to spore production over a flat surface, gills achieve a maximum 20-fold increase in surface area. The branching of gills produces the same increase in surface area as the formation of free-standing lamellulae (short gills). The addition of lamellulae between every second gill would offer a slightly greater increase in surface area in comparison to the addition of lamellulae between every pair of opposing gills, but this morphology does not appear in nature. Analysis of photographs of mushrooms demonstrates an excellent match between natural gill arrangements and configurations predicted by our model. PMID:20965062

  10. Characterization of abalone Haliotis tuberculata-Vibrio harveyi interactions in gill primary cultures.

    PubMed

    Pichon, Delphine; Cudennec, Benoit; Huchette, Sylvain; Djediat, Chakib; Renault, Tristan; Paillard, Christine; Auzoux-Bordenave, Stéphanie

    2013-10-01

    The decline of European abalone Haliotis tuberculata populations has been associated with various pathogens including bacteria of the genus Vibrio. Following the summer mortality outbreaks reported in France between 1998 and 2000, Vibrio harveyi strains were isolated from moribund abalones, allowing in vivo and in vitro studies on the interactions between abalone H. tuberculata and V. harveyi. This work reports the development of primary cell cultures from abalone gill tissue, a target tissue for bacterial colonisation, and their use for in vitro study of host cell-V. harveyi interactions. Gill cells originated from four-day-old explant primary cultures were successfully sub-cultured in multi-well plates and maintained in vitro for up to 24 days. Cytological parameters, cell morphology and viability were monitored over time using flow cytometry analysis and semi-quantitative assay (XTT). Then, gill cell cultures were used to investigate in vitro the interactions with V. harveyi. The effects of two bacterial strains were evaluated on gill cells: a pathogenic bacterial strain ORM4 which is responsible for abalone mortalities and LMG7890 which is a non-pathogenic strain. Cellular responses of gill cells exposed to increasing concentrations of bacteria were evaluated by measuring mitochondrial activity (XTT assay) and phenoloxidase activity, an enzyme which is strongly involved in immune response. The ability of gill cells to phagocyte GFP-tagged V. harveyi was evaluated by flow cytometry and gill cells-V. harveyi interactions were characterized using fluorescence microscopy and transmission electron microscopy. During phagocytosis process we evidenced that V. harveyi bacteria induced significant changes in gill cells metabolism and immune response. Together, the results showed that primary cell cultures from abalone gills are suitable for in vitro study of host-pathogen interactions, providing complementary assays to in vivo experiments. PMID:23756730

  11. Wind-Eroded Terrain near Olympus Mons

    NASA Technical Reports Server (NTRS)

    2003-01-01

    MGS MOC Release No. MOC2-569, 9 December 2003

    This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows wind-eroded material, possibly sedimentary rock, among the ridges of the Lycus Sulci region west of Olympus Mons. The darker surfaces and the dark-toned ripples on those surfaces indicate there may be windblown sand present in these areas. This October 2003 picture is located near 17.8oN, 143.7oW. The image covers an area approximately 3 km (1.9 mi) wide and is illuminated from the lower left.

  12. Titanium dioxide nanoparticles modulate the toxicological response to cadmium in the gills of Mytilus galloprovincialis.

    PubMed

    Della Torre, Camilla; Balbi, Teresa; Grassi, Giacomo; Frenzilli, Giada; Bernardeschi, Margherita; Smerilli, Arianna; Guidi, Patrizia; Canesi, Laura; Nigro, Marco; Monaci, Fabrizio; Scarcelli, Vittoria; Rocco, Lucia; Focardi, Silvano; Monopoli, Marco; Corsi, Ilaria

    2015-10-30

    We investigated the influence of titanium dioxide nanoparticles (nano-TiO2) on the response to cadmium in the gills of the marine mussel Mytilus galloprovincialis in terms of accumulation and toxicity. Mussels were in vivo exposed to nano-TiO2, CdCl2, alone and in combination. Several cellular biomarkers were investigated in gills: ABC transport proteins and metallothioneins at gene/protein (abcb1, abcc-like and mt-20) and functional level, GST activity, NO production and DNA damage (Comet assay). Accumulation of total Cd and titanium in gills as in whole soft tissue was also investigated. Significant responses to Cd exposure were observed in mussel gills as up-regulation of abcb1 and mt-20 gene transcription, increases in total MT content, P-gp efflux and GST activity, DNA damage and NO production. Nano-TiO2 alone increased P-gp efflux activity and NO production. When combined with Cd, nano-TiO2 reduced the metal-induced effects by significantly lowering abcb1 gene transcription, GST activity, and DNA damage, whereas, additive effects were observed on NO production. A lower concentration of Cd was observed in the gills upon co-exposure, whereas, Ti levels were unaffected. A competitive effect in uptake/accumulation of nano-TiO2 and Cd seems to occur in gills. A confirmation is given by the observed absence of adsorption of Cd onto nano-TiO2 in sea water media. PMID:25956639

  13. A second glutamine synthetase gene with expression in the gills of the gulf toadfish (opsanus beta)

    SciTech Connect

    Walsh, Patrick J.; Mayer, Gregory D.; Medina, Monica; Bernstein, Matthew L.; Barimo, John F.; Mommsen, Thomas P.

    2003-05-08

    Enzyme and molecular biology approaches were used to more completely characterize the expression of the nitrogen metabolism enzyme glutamine synthetase [GSase; L-glutamate: ammonia ligase (ADP-forming), E.C. 6.3.1.2] in a variety of tissues of the gulf toadfish (Opsanus beta) subjected to unconfined (ammonotelic) and confined (ureotelic) conditions. Enzymological results demonstrate that while weight-specific GSase activities rank in the order of brain > liver > stomach {approx} kidney > intestine > gill> heart/spleen > muscle, when tissue mass is used to calculate a glutamine synthetic potential, the liver has the greatest, followed by muscle > stomach and intestine with minor contributions from the remaining tissues. Additionally, during confinement stress, GSase activity only increases significantly in liver (5-fold) and muscle (2-fold), tissues which previously showed significant expression of the other enzymes of urea synthesis. RT PCR and RACE PCR revealed the presence of a second GSas e cDNA from gill tissue that appears to share relatively low nucleotide and amino acid sequence similarity ({approx}73 percent) with the original GSase cloned from liver, and furthermore lacks a mitochondrial leader targeting sequence. RT PCR and restriction digestion experiments demonstrated that mRNA from the original ''liver'' GSase is expressed in all tissues examined (liver, gill, stomach, intestine, kidney, brain and muscle), whereas the new ''gill'' form shows expression primarily in the gill. Enzyme activities of gill GSase also exhibit a different subcellular compartmentation with apparent exclusive expression in the soluble compartment, whereas other tissues expressing the ''liver'' form show both cytoplasmic and mitochondrial activities. Finally, phylogenetic analysis of a number of GSases demonstrates that the toadfish gill GSase has a greater affinity for a clade that includes the Xenopus GSase genes and one of two Fugu GSase genes, than it has for a clade

  14. Life science experiments during parabolic flight: The McGill experience

    NASA Technical Reports Server (NTRS)

    Watt, D. G. D.

    1988-01-01

    Over the past twelve years, members of the Aerospace Medical Research Unit of McGill University have carried out a wide variety of tests and experiments in the weightless condition created by parabolic flight. This paper discusses the pros and cons of that environment for the life scientist, and uses examples from the McGill program of the types of activities which can be carried out in a transport aircraft such as the NASA KC-135.

  15. Respiratory toxicity of cyanobacterial aphantoxins from Aphanizomenon flos-aquae DC-1 in the zebrafish gill.

    PubMed

    Zhang, De Lu; Liu, Si Yi; Zhang, Jing; Zhang, Jian Kun; Hu, Chun Xiang; Liu, Yong Ding

    2016-07-01

    Aphantoxins from Aphanizomenon flos-aquae are frequently identified in eutrophic waterbodies worldwide. These toxins severely endanger environmental safety and human health due to the production of paralytic shellfish poisons (PSPs). Although the molecular mechanisms of aphantoxin neurotoxicity have been studied, many questions remain to be resolved such as in vivo alterations in branchial histology and neurotransmitter inactivation induced by these neurotoxins. Aphantoxins extracted from a naturally isolated strain of A. flos-aquae DC-1 were determined by high performance liquid chromatography. The basic components of the isolated aphantoxins identified were gonyautoxin 1 (GTX1), gonyautoxin 5 (GTX5), and neosaxitoxin (neoSTX), which comprised 34.04, 21.28, and 12.77% of the total, respectively. Zebrafish (Danio rerio) was administrated 5.3 or 7.61mg STX equivalents (eq)/kg (low and high doses, respectively) of the A. flos-aquae DC-1 aphantoxins by intraperitoneal injection. Histological alterations and changes in neurotransmitter inactivation in the gills of zebrafish were investigated for 24h following exposure. Aphantoxin exposure significantly increased the activities of gill alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and resulted in histological alterations in the gills during the first 12h of exposure, indicating the induction of functional and structural damage. Gill acetylcholinesterase (AChE) and monoamine oxidase (MAO) activities were inhibited significantly, suggesting an alteration of neurotransmitter inactivation in zebrafish gills. The observed alterations in gill structure and function followed a time- and dose-dependent pattern. The results demonstrate that aphantoxins or PSPs lead to structural damage and altered function in the gills of zebrafish, including changes in histological structure and increases in the activities of AST and ALT. The inhibition of the activities of AChE and MAO suggest that aphantoxins or PSPs

  16. Soil erodibility for water erosion: A perspective and Chinese experiences

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Zheng, Fenli; Römkens, Mathias J. M.; Darboux, Frédéric

    2013-04-01

    Knowledge of soil erodibility is an essential requirement for erosion prediction, conservation planning, and the assessment of sediment related environmental effects of watershed agricultural practices. This paper reviews the status of soil erodibility evaluations and determinations based on 80 years of upland area erosion research mainly in China and the USA. The review synthesizes the general research progress made by discussing the basic concepts of erodibility and its evaluation, determination, and prediction as well as knowledge of its spatio-temporal variations. The authors found that soil erodibility is often inappropriately or inaccurately applied in describing soil loss caused by different soil erosion component processes and mechanisms. Soil erodibility indicators were related to intrinsic soil properties and exogenic erosional forces, measurements, and calculations. The present review describes major needs including: (1) improved definition of erodibility, (2) modified erodibility determinations in erosion models, especially for specific geographical locations and in the context of different erosion sub-processes, (3) advanced methodologies for quantifying erodibilities of different soil erosion sub-processes, and (4) a better understanding of the mechanism that causes temporal variations in soil erodibility. The review also provides a more rational basis for future research on soil erodibility and supports predictive modeling of soil erosion processes and the development of improved conservation practices.

  17. Gilles vs Pugh and the lost letter.

    PubMed

    Paull, J D

    2009-07-01

    In June 1842 the wife of Lewis W Gilles, a banker in Launceston, wrote to Mrs Pugh, inviting her and her husband, Mr William Russ Pugh, to an entertainment and ball. The Pughs neither responded to the invitation, nor attended the ball. Mrs Gilles mentioned the discourtesy of their non-attendance to a friend, who the following morning brought the complaint to the attention of Dr Pugh. Pugh immediately wrote a brief note explaining that neither he nor his wife had received the invitation. Further correspondence between Gilles and Pugh ensued, becoming more and more bitter until Pugh publicly insulted Gilles. The Launceston Club, of which both men were members, ultimately became a casualty of the dispute and was dissolved. A Supreme Court defamation and libel case followed with Gilles as plaintiff and Pugh as defendant. Gilles won the case but received only token damages. And the missing letter? Too late, Mrs Pugh's maid found it tucked between the pages of a periodical on the dresser PMID:19705633

  18. Tonic, phasic and cortical arousal in Gilles de la Tourette's syndrome.

    PubMed Central

    Bock, R D; Goldberger, L

    1985-01-01

    This study explored the hypothesis that Gilles de la Tourette's syndrome involves a disturbance in arousal modulation. The experimental group consisted of 20 unmedicated subjects with the Gilles de la Tourette's syndrome, and the control group of 20 subjects with chronic medical illnesses (haemophilia, von Willebrandt's disease and diabetes). There were differences between groups in the manner in which log conductance level changed over time during sound and light habituation experiments involving mild levels of stimulation with the Gilles de la Tourette group showing less change in arousal level over trials than the control group. No group differences were found in measures of phasic arousal, rate of spontaneous fluctuations and performance on two tasks that have been related to cortical arousal. It is suggested that the slower change in log conductance level in the Gilles de la Tourette group during the sound and light habituation experiments indicates that reticular activity is more persistent in these patients. PMID:3859582

  19. Submerged and eroded drumlins off northeastern Massachusetts

    USGS Publications Warehouse

    Oldale, R.N.; Knebel, H. J.; Bothner, Michael H.

    1994-01-01

    Streamlined, oval-shaped, oriented topographic highs in Massachusetts Bay are identified as the erosional remnants of drumlins. The topographic highs correlate with outlines of lag gravel deposits on the sea floor and both the highs and lag gravel seafloor footprint have a distinct east-southeast long axis trend. This trend is similar to the preferred orientation of the long axes of drumlins in the Boston Basin and indicates the flow direction of the late Wisconsinan Laurentide Ice Sheet. Modification of the drumlins occurred during two passages of the shoreline, the first during the late Wisconsinan regression when the drumlins were only slightly eroded. The second passage of the shoreline occurred during the marine transgression, when erosion, in the form of cliff-face retreat, removed the upper part of the drumlins. ?? 1994.

  20. Seasonal control of particle clearance by isolated gills from the clam Mercenaria mercenaria.

    PubMed

    Gainey, Louis F

    2007-07-01

    Pieces of gill isolated from the clam Mercenaria mercenaria clear colloidal graphite from seawater, and the clearance rates are measurable. 5-Hydroxytryptamine (5-HT) had a biphasic effect on clearance rates: concentrations from 10(-6) to 10(-5) mol l(-1) 5-HT increased clearance, but higher concentrations reduced it. During the summer, the gills were less responsive to 5-HT: the threshold increased from 1 x 10(-6) to 5 x 10(-6) mol l(-1), and although the rate was still maximal at 10(-5) mol l(-1), it was significantly lower than the maximal rate in the winter. At 10(-5) mol l(-1) 5-HT, which maximized clearance, the lateral cilia were active, the interfilament space decreased and the diameter of the water tubes increased. Higher concentrations of 5-HT contracted the gill musculature, which inhibited the lateral cilia, decreased the interfilament space even more and decreased the diameter of the water tubes. The nitric oxide (NO) generator DEANO stimulated clearance in the winter but had no effect during the summer. L-NAME, an inhibitor of NO synthesis, diminished the effect of 5-HT during the winter but was ineffective during the summer. The diminished response to 5-HT of winter gills treated with L-NAME was statistically equal to the response of the gills to 5-HT during the summer. Dopamine (DA) inhibited clearance, and the gills were more sensitive to DA in winter than in summer. Microscopic examination of untreated gills revealed little or no lateral ciliary activity, and clearance was minimal. Thus, clearance rates of isolated gills behave in a manner consistent with the seasonality and pharmacology of the lateral cilia and branchial musculature. PMID:17601956

  1. Cell signaling and ion transport across the fish gill epithelium.

    PubMed

    Evans, David H

    2002-08-01

    A large array of circulating and local signaling agents modulate transport of ions across the gill epithelium of fishes by either affecting transport directly or by altering the size and distribution of transporting cells in the epithelium. In some cases, these transport effects are in addition to cardiovascular effects of the same agents, which may affect the perfusion pathways in the gill vasculature and, in turn, affect epithelial transport indirectly. Prolactin is generally considered to function in freshwater, because it is the only agent that allows survival of some hypophysectomized fish species in freshwater. It appears to function by either reducing branchial permeability, Na,K-activated ATPase activity, or reducing the density of chloride cells. Cortisol was initially considered to produce virtually opposite effects (e.g., stimulation of Na,K-activated ATPase and of chloride cell size and density), but more recent studies have found that this steroid stimulates ionic uptake in freshwater fishes, as well as the activity of H-ATPase, an enzyme thought to be central to ionic uptake. Thus, cortisol may function in both high and low salinities. Growth hormone and insulin-like growth factor appear to act synergistically to affect ion regulation in seawater fishes, stimulating both Na,K-activated ATPase and Na-K-2Cl co-transporter activity, and chloride cell size, independent of their effects on growth. Some of the effects of the GH-IGF axis may be via stimulation of the number of cortisol receptors. Thyroid hormones appear to affect seawater ion regulation indirectly, by stimulating the GH-IGF axis. Natriuretic peptides were initially thought to stimulate gill ionic extrusion, but recent studies have not corroborated this finding, so it appears that the major mode of action of these peptides may be reduction of salt loading by inhibition of oral ingestion and intestinal ionic uptake. Receptors for both arginine vasotocin and angiotensin have been described in

  2. Identification of Methanotrophic Biomarker Lipids in the Symbiont-Containing Gills of Seep Mussels

    NASA Technical Reports Server (NTRS)

    Jahnke, L. L.; Zahiralis, K. D.; Klein, H. P.; Morrison, David (Technical Monitor)

    1994-01-01

    Mussels collected from hydrocarbon seeps in the Gulf of Mexico grow with methane as sole carbon and energy source due to a symbiotic association with methane-oxidizing bacteria. Transmission electron micrographs of mussel gills show cells with stacked intracytoplasmic membranes similar to type I methanotrophic bacteria. Methanotrophs are known to synthesize several types of cyclic triterpenes, hopanoids and methyl sterols, as well as unique monounsaturated fatty acid, double bond positional isomers that serve as biomarkers for this group. Lipid analysis of dissected mussels demonstrated the presence of these biomarkers predominantly in the gill tissue with much smaller amounts in mantle and remaining body tissues. Gill tissue contained 1150 micrograms/g dry wt. of hopanepolyol derivatives and diplopterol while the mantle tissue contained only 17 micrograms/g. The C16 monounsaturated fatty acids (16:1) characteristic of type I methanotrophic membranes dominated the gill tissue making up 53% of the total while only 5% 16:1 was present in the mantle tissue. The methyl sterol distribution was more dispersed. The predominant sterol in all tissues was cholesterol with lesser amounts of other desmethyl and 4-methyl sterols. The gill and mantle tissues contained 3461 micrograms (17% methyl) and 2750 micrograms (5% methyl) sterol per gm dry wt., respectively. Methyl sterol accounted for 44% of the sterol esters isolated from the gill, suggesting active demethylation of the methanotrophic sterols in this tissue. The use of lipid biomarkers could provide an effective means for identifying host-symbiont relationships.

  3. Biologically erodable microspheres as potential oral drug delivery systems

    NASA Astrophysics Data System (ADS)

    Mathiowitz, Edith; Jacob, Jules S.; Jong, Yong S.; Carino, Gerardo P.; Chickering, Donald E.; Chaturvedi, Pravin; Santos, Camilla A.; Vijayaraghavan, Kavita; Montgomery, Sean; Bassett, Michael; Morrell, Craig

    1997-03-01

    Biologically adhesive delivery systems offer important advantages1-5 over conventional drug delivery systems6. Here we show that engineered polymer microspheres made of biologically erodable polymers, which display strong adhesive interactions with gastrointestinal mucus and cellular linings, can traverse both the mucosal absorptive epithelium and the follicle-associated epithelium covering the lymphoid tissue of Peyer's patches. The polymers maintain contact with intestinal epithelium for extended periods of time and actually penetrate it, through and between cells. Thus, once loaded with compounds of pharmacological interest, the microspheres could be developed as delivery systems to transfer biologically active molecules to the circulation. We show that these microspheres increase the absorption of three model substances of widely different molecular size: dicumarol, insulin and plasmid DNA.

  4. Mini rainfall simulation for assessing soil erodibility

    NASA Astrophysics Data System (ADS)

    Peters, Piet; Palese, Dina; Baartman, Jantiene

    2016-04-01

    The mini rainfall simulator is a small portable rainfall simulator to determine erosion and water infiltration characteristics of soils. The advantages of the mini rainfall simulator are that it is suitable for soil conservation surveys and light and easy to handle in the field. Practical experience over the last decade has shown that the used 'standard' shower is a reliable method to assess differences in erodibility due to soil type and/or land use. The mini rainfall simulator was used recently in a study on soil erosion in olive groves (Ferrandina-Italy). The propensity to erosion of a steep rain-fed olive grove (mean slope ~10%) with a sandy loam soil was evaluated by measuring runoff and sediment load under extreme rain events. Two types of soil management were compared: spontaneous grass as a ground cover (GC) and tillage (1 day (T1) and 10 days after tillage (T2)). Results indicate that groundcover reduced surface runoff to approximately one-third and soil-losses to zero compared with T1. The runoff between the two tilled plots was similar, although runoff on T1 plots increased steadily over time whereas runoff on T2 plots remained stable.

  5. Pyrosequencing reveals bacteria carried in different wind eroded sediments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the microbial communities carried in wind-eroded sediments from various soil types and land management systems. A novel technique, pyrosequencing, promises to expand our understanding of the vast microbial diversity of soils and eroded sediments as it can sequence between 10-10...

  6. Coherence of erodibility for erosion processes and different scales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Erosion is one of the least reliably defined elements of many hydraulic projects. Earthen embankments (i.e. dams and levees) are an example of hydraulic projects for which erosion and erodibility have not been reliably defined in the past. Characterizing material erodibility is one of the essentia...

  7. Gill diseases of cultured salmonids in Ontario.

    PubMed Central

    Daoust, P Y; Ferguson, H W

    1983-01-01

    Between 1977 and 1981, the Fish Pathology Laboratory of the Ontario Veterinary College received 239 cases from trout farms of southern Ontario, 51 (21.3%) of which had diseased gills. Branchial lesions in 86.3% of these 51 cases were characterized by marked lamellar epithelial hyperplasia with epithelial hypertrophy and lamellar fusion. Filamentous bacteria were seen on the surface of the branchial filaments and lamellae in 68.6% of the cases. Our observations highlight the importance of gill diseases as a production problem of farmed salmonids in southern Ontario. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. Fig. 8. Fig. 9. PMID:6416657

  8. Erodibility controls on the vertical and horizontal scalings of topography : a case study in the Himalayas

    NASA Astrophysics Data System (ADS)

    Godard, V.; Steer, P.

    2011-12-01

    Understanding the scaling properties of topography in actively uplifting areas is a major issue in quantitative geomorphology. Analytical formulations of non-glaciated landscape evolution clearly demonstrate that metrics such as local relief or drainage density are explicitly related to the spatial distribution of tectonic uplift, precipitation, erodibility and local slope across the landscape. However, in most regions, these parameters are seldom documented with enough resolution and precision to allow a systematic and statistically significant investigation of their relationships with both horizontal and vertical scaling properties of topography. A notable exception is the Himalaya of central Nepal, where the last 20 years of tectonic and geomorphological research have produced one of the densest regional data-set and documented major gradients in uplift and precipitation across the range [e.g. Lavé and Avouac, 2001; Bookhagen and Burbank, 2006]. The purpose of our study is to use this data in order to develop a detailed investigation of the influence of the erodibility parameter in controlling the structure and texture of the landscape. We first build on the derivation of total catchment relief of Tucker and Whipple [2002] to include the contribution of precipitation in addition to uplift, erodibility. Then, by minimizing the misfit between observed and predicted catchment relief, we assess the erodibility parameter for each second or third order catchment in our area of investigation. The resultant erodibility map (1) matches the distribution of geological units and (2) reveals a number of interesting second order patterns, such as along-strike fluctuations in the Lesser Himalayas and a significant decrease in erodibility coincident with the location of the MCT zone. This latter result possibly highlights the effect of intense schistosity and fracturation on large scale erosion efficiency [Molnar et al., 2007]. Then to assess the influence of erodibility on

  9. Food and Gill Exchange of Toxic Substances

    EPA Science Inventory

    Food and Gill Exchange of Toxic Substances (FGETS) is a FORTRAN simulation model that predicts temporal dynamics of fish whole body concentration (ug chemical/(g live weight fish)) of non ionic, non metabolized, organic chemicals that are bioaccumulated from either: (a) water onl...

  10. Six cases of Gilles de la Tourette's syndrome.

    PubMed

    Fernando, S J

    1976-05-01

    Six cases of Gilles de la Tourette's syndrome are discussed in the light of conflicting views on the aetiology of the condition. It is hypothesized that the onset of coprolalia in patients with persistent childhood tics indicates a disturbances of the normal balance between a need for tension relief by swearing and a capacity to control such vocal activity. Some conclusions are drawn on the management of the syndrome by the use of butyrophenones, massed practice of tics, and the promotion of personality development. A flexible approach geared to the individual patient's particular needs is recommended. PMID:1064460

  11. Apoptotic effects and glucose-6-phosphate dehydrogenase responses in liver and gill tissues of rainbow trout treated with chlorpyrifos.

    PubMed

    Topal, Ahmet; Atamanalp, Muhammed; Oruç, Ertan; Kırıcı, Muammer; Kocaman, Esat Mahmut

    2014-12-01

    We investigated apoptotic effects and changes in glucose-6-phosphate dehydrogenase (G6PD) enzyme activity in liver and gill tissues of fish exposed to chlorpyrifos. Three different chlorpyrifos doses (2.25, 4.5 and 6.75 μg/L) were administrated to rainbow trout at different time intervals (24, 48, 72 and 96 h). Acute exposure to chlorpyrifos showed time dependent decrease in G6PD enzyme activity at all concentrations (p < 0.05). Immunohistochemical results showed that chlorpyrifos caused mucous cell loss in gill tissue and apoptosis via caspase-3 activation in fish. The present study suggested that chlorpyrifos inhibits G6PD enzyme and causes mucous cell loss in gill and apoptosis in gill and liver tissues. PMID:25438950

  12. Gill remodeling in fish--a new fashion or an ancient secret?

    PubMed

    Nilsson, Göran E

    2007-07-01

    While a large respiratory surface area is good for gas exchange, it also poses several problems, including energetically unfavorable fluxes of water and ions. As a result, fishes appear to have a respiratory surface area that is matched to their oxygen demands. When faced with changes in their need for oxygen uptake, e.g. through altered physical activity or altered ambient oxygen levels, fishes have long been known to make two different adjustments: (1) to change the water flow over the gills or (2) to change the blood flow inside the gills. It has recently become clear that at least some teleosts have a third option: to reversibly remodel the gill morphology. Studies have shown that the lamellae of crucian carp Carassius carassius gills are embedded in a cell mass during normoxic conditions or at low temperature, while much of this cell mass dies off in hypoxia and at higher temperatures, thereby exposing a much larger respiratory surface area. Gill remodeling has subsequently been seen in two more cyprinids and in the mangrove killifish Kryptolebias marmoratus. In the latter case it appears to be an adaptation to periods of air exposure. Gill remodeling in response to changing respiratory requirements could be an ancient mechanism, occurring in many more teleosts than presently known. It is tempting to suggest that gill remodeling has been overlooked in many fishes, either because it is relatively subtle in some species, or because fishes are often kept at the warmer end of their temperature range where they need fully protruding lamellae. PMID:17601943

  13. Quantitative Molecular Phenotyping of Gill Remodeling in a Cichlid Fish Responding to Salinity Stress*

    PubMed Central

    Kültz, Dietmar; Li, Johnathon; Gardell, Alison; Sacchi, Romina

    2013-01-01

    A two-tiered label-free quantitative (LFQ) proteomics workflow was used to elucidate how salinity affects the molecular phenotype, i.e. proteome, of gills from a cichlid fish, the euryhaline tilapia (Oreochromis mossambicus). The workflow consists of initial global profiling of relative tryptic peptide abundances in treated versus control samples followed by targeted identification (by MS/MS) and quantitation (by chromatographic peak area integration) of validated peptides for each protein of interest. Fresh water acclimated tilapia were independently exposed in separate experiments to acute short-term (34 ppt) and gradual long-term (70 ppt, 90 ppt) salinity stress followed by molecular phenotyping of the gill proteome. The severity of salinity stress can be deduced with high technical reproducibility from the initial global label-free quantitative profiling step alone at both peptide and protein levels. However, an accurate regulation ratio can only be determined by targeted label-free quantitative profiling because not all peptides used for protein identification are also valid for quantitation. Of the three salinity challenges, gradual acclimation to 90 ppt has the most pronounced effect on gill molecular phenotype. Known salinity effects on tilapia gills, including an increase in the size and number of mitochondria-rich ionocytes, activities of specific ion transporters, and induction of specific molecular chaperones are reflected in the regulation of abundances of the corresponding proteins. Moreover, specific protein isoforms that are responsive to environmental salinity change are resolved and it is revealed that salinity effects on the mitochondrial proteome are nonuniform. Furthermore, protein NDRG1 has been identified as a novel key component of molecular phenotype restructuring during salinity-induced gill remodeling. In conclusion, besides confirming known effects of salinity on gills of euryhaline fish, molecular phenotyping reveals novel insight into

  14. Sediment texture, erodibility, and composition in the Northern Gulf of Mexico and their potential impacts on hypoxia formation

    NASA Astrophysics Data System (ADS)

    Mickey, Rangley; Xu, Kehui; Libes, Susan; Hill, Jenna

    2015-02-01

    A region of hypoxic waters has formed annually over the past several decades in the northern Gulf of Mexico. This has motivated the studies of mechanisms controlling the development of hypoxia. Both field and laboratory approaches were used to examine sediment texture, erodibility, and composition. Sediment texture analyses show that grain size relates to the proximity to the Mississippi and Atchafalaya river deltas and to the remnants of shifts in the Mississippi and Atchafalaya deltaic lobes. Temporal variability in erodibility relates to seasonal weather patterns, with more energetic wave conditions in winter and spring setting up an active bottom layer that increases erodibility, compared to quiescent summers that allow for seabed consolidation. The amount of eroded material is fairly low until shear stress levels in the bottom boundary layer exceed 0.4 Pa. An organically enriched fluff layer was found at the sediment-water interface, which is highly erodible under low shear stress levels. Eroded volatile suspended solids (a proxy for organic material) vs. increasing levels of shear stress revealed a distinct pattern at all sample areas; higher concentrations of organic material were eroded at the lowest (0.01 Pa) and highest (0.6 Pa) applied shear stresses, and there was a higher ratio of the volatile to total suspended solids at 0.01 Pa. Based on erodibility experiments and modeling data analysis, the low shear stress levels during the quiescent periods in summer were sometimes high enough to resuspend this fluff layer, but not underlying sediment, thereby potentially facilitating the development of bottom water hypoxia.

  15. Divergent immunity and energetic programs in the gills of migratory and resident Oncorhynchus mykiss.

    PubMed

    Sutherland, Ben J G; Hanson, Kyle C; Jantzen, Johanna R; Koop, Ben F; Smith, Christian T

    2014-04-01

    Divergent life history strategies occur in steelhead or rainbow trout Oncorhynchus mykiss, and many populations produce both migrant (anadromous fish that move to the ocean after rearing) and resident (do not migrate and remain in fresh water) individuals. Mechanisms leading to each type are only partially understood; while the general tendency of a population is heritable, individual tendency may be plastic, influenced by local environment. Steelhead hatchery programmes aim to mitigate losses in wild stocks by producing trout that will migrate to the ocean and not compete with wild trout for limited freshwater resources. To increase our understanding of gill function in these migratory or resident phenotypes, here we compare gill transcriptome profiles of hatchery-released fish either at the release site (residents) or five river kilometres downstream while still in full fresh water (migrants). To test whether any of these genes can be used as predictive markers for smoltification, we compared these genes between migrant-like and undifferentiated trout while still in the hatchery in a common environment (prerelease). Results confirmed the gradual process of smoltification, and the importance of energetics, gill remodelling and ion transport capacity for migrants. Additionally, residents overexpressed transcripts involved in antiviral defences, potentially for immune surveillance via dendritic cells in the gills. The best smoltification marker candidate was protein s100a4, expression of which was highly correlated with Na(+) , K(+) ATPase (NKA) activity and smolt-like morphology in pre- and postrelease trout gills. PMID:24612010

  16. Copper exposure and ciliary function in gill tissue of Mytilus californianus

    SciTech Connect

    Smith, J.R.

    1985-10-01

    In this study, the biological effects of chronic, sublethal exposure to a metal (copper) on a marine bivalve, Mytilus californianus, were investigated. The biological unit of interest was the function of cilia associated with gill structures. Effects of copper exposure on ciliary activity were assessed using three parameters: 1) the ability of intact animals to remove suspended algae from seawater; 2) cilioregulatory neurotransmitter levels, dopamine (DA) and serotonin (5HT), in the visceral ganglia; and 3) characteristics of putative receptor sites for DA and 5HT in gill tissue.

  17. Living his writings: the example of neurologist G. Gilles de la Tourette.

    PubMed

    Walusinski, Olivier; Duncan, Gregory

    2010-10-30

    Gilles de la Tourette is known for the disease which now bears his name. As one of the closest followers of Jean-Martin Charcot, he always remained faithful to his mentor's views and was one of the most vehement defenders of La Salpêtrière. His activities in the management of hysterics and in hypnotism helped build his reputation during his lifetime, but are now largely forgotten. Gilles de la Tourette had an unusual personality, with hypomanic and histrionic traits. We present some ignored aspects of his life based on the discovery of personal letters which illuminate the hidden side of this famous neurologist. PMID:20672344

  18. Differential effects of biochar on soils within an eroded field

    NASA Astrophysics Data System (ADS)

    Schumacher, Thomas; Chintala, Rajesh; Sandhu, Saroop; Kumar, Sandeep; Clay, Dave; Gelderman, Ron; Papiernik, Sharon; Malo, Douglas; Clay, Sharon; Julson, Jim

    2015-04-01

    Future uses of biochar will in part be dependent not only on the effects of biochar on soil processes but also on the availability and economics of biochar production. If pyrolysis for production of bio-oil and syngas becomes wide-spread, biochar as a by-product of bio-oil production will be widely available and relatively inexpensive compared to the production of biochar as primary product. Biochar produced as a by-product of optimized bio-oil production using regionally available feedstocks was examined for properties and for use as an amendment targeted to contrasting soils within an eroded field in an on-farm study initiated in 2013 at Brookings, South Dakota, USA. Three plant based biochar materials produced from carbon optimized gasification of corn stover (Zea mays L.), Ponderosa pine (Pinus ponderosa Lawson and C. Lawson) wood residue, and switchgrass (Panicum virgatum L.) were applied at a 1% (w/w) rate to a Maddock soil (Sandy, Mixed, Frigid Entic Hapludolls) located in an eroded upper landscape position and a Brookings soil (Fine-Silty, Mixed, Superactive, Frigid Pachic Hapludolls) located in a depositional landscape position. The cropping system within this agricultural landscape was a corn (Zea mays L.) and soybean (Glycine max L.) rotation. Biochar physical and chemical properties for each of the feedstocks were determined including pH, surface area, surface charge potential, C-distribution, ash content, macro and micro nutrient composition. Yields, nutrient content, and carbon isotope ratio measurements were made on the harvested seed. Soil physical properties measured included water retention, bulk density, and water infiltration from a ponded double ring infiltrometer. Laboratory studies were conducted to determine the effects of biochar on partitioning of nitrate and phosphorus at soil surface exchange complex and the extracellular enzymes activity of C and N cycles. Crop yields were increased only in the Maddock soil. Biochar interacted with each

  19. Antioxidant deficit in gills of Pacific oyster (Crassostrea gigas) exposed to chlorodinitrobenzene increases menadione toxicity.

    PubMed

    Trevisan, Rafael; Arl, Miriam; Sacchet, Cássia Lopes; Engel, Cristiano Severino; Danielli, Naissa Maria; Mello, Danielle Ferraz; Brocardo, Caroline; Maris, Angelica Francesca; Dafre, Alcir Luiz

    2012-02-01

    Disturbances in antioxidant defenses decrease cellular protection against oxidative stress and jeopardize cellular homeostasis. To knock down the antioxidant defenses of Pacific oyster Crassostrea gigas, animals were pre-treated with 1-chloro-2,4-dinitrobenzene (CDNB) and further challenged with pro-oxidant menadione (MEN). CDNB pre-treatment (10 μM for 18 h) was able to consume cellular thiols in gills, decreasing GSH (53%) and decrease protein thiols (25%). CDNB pre-treatment also disrupted glutathione reductase and thioredoxin reductase activity in the gills, but likewise strongly induced glutathione S-transferase activity (270% increase). Surprisingly, hemocyte viability was greatly affected 24 h after CDNB removal, indicating a possible vulnerability of the oyster immune system to electrophilic attack. New in vivo approaches were established, allowing the identification of higher rates of GSH-CDNB conjugate export to the seawater and enabling the measurement of the organic peroxide consumption rate. CDNB-induced impairment in antioxidant defenses decreased the peroxide removal rate from seawater. After showing that CDNB decreased gill antioxidant defenses and increased DNA damage in hemocytes, oysters were further challenged with 1 mM MEN over 24 h. MEN treatment did not affect thiol homeostasis in gills, while CDNB pre-treated animals recovered GSH and PSH to the control level after 24 h of depuration. Interestingly, MEN intensified GSH and PSH loss and mortality in CDNB-pre-treated animals, showing a clear synergistic effect. The superoxide-generating one-electron reduction of MEN was predominant in gills and may have contributed to MEN toxicity. These results support the idea that antioxidant-depleted animals are more susceptible to oxidative attack, which can compromise survival. Data also corroborate the idea that gills are an important detoxifying organ, able to dispose of organic peroxides, induce phase II enzymes, and efficiently export GSH

  20. Estimate Soil Erodibility Factors Distribution for Maioli Block

    NASA Astrophysics Data System (ADS)

    Lee, Wen-Ying

    2014-05-01

    The natural conditions in Taiwan are poor. Because of the steep slopes, rushing river and fragile geology, soil erosion turn into a serious problem. Not only undermine the sloping landscape, but also created sediment disaster like that reservoir sedimentation, river obstruction…etc. Therefore, predict and control the amount of soil erosion has become an important research topic. Soil erodibility factor (K) is a quantitative index of distinguish the ability of soil to resist the erosion separation and handling. Taiwan soil erodibility factors have been calculated 280 soil samples' erodibility factors by Wann and Huang (1989) use the Wischmeier and Smith nomorgraph. 221 samples were collected at the Maioli block in Miaoli. The coordinates of every sample point and the land use situations were recorded. The physical properties were analyzed for each sample. Three estimation methods, consist of Kriging, Inverse Distance Weighted (IDW) and Spline, were applied to estimate soil erodibility factors distribution for Maioli block by using 181 points data, and the remaining 40 points for the validation. Then, the SPSS regression analysis was used to comparison of the accuracy of the training data and validation data by three different methods. Then, the best method can be determined. In the future, we can used this method to predict the soil erodibility factors in other areas.

  1. Non-electrolyte permeability of trout gills: effect of temperature and adrenaline

    PubMed Central

    Isaia, J.

    1979-01-01

    1. The gill permeability to various non-electrolytes (Ps) was measured in fresh-water and sea-water adapted trout (Salmo gairdneri). This study was performed in vitro using a `head-perfused' preparation. The influence of temperature and adrenaline (10-6 M) on permeability to non-electrolytes was also investigated. 2. During salt adaptation Pbutanol and Pwater decrease, Pmannitol rises and Pdextran stays constant. In view of recently acquired morphological data these results back up the hypothesis of different pathways across the gill epithelium (transcellular, vesicular and paracellular) according to the physico-chemical characteristics of the molecules. The low selectivity of the gill epithelium as a function of the liposolubility of the molecules used testifies to the hydrophilic nature of diffusion across this epithelium, a feature becoming more pronounced during salt adaptation. 3. The activation energies are about 4 kcal/mol, an energy comparable to diffusion in water for most of the substances tested, exceptions being butanol for fresh-water adapted gills and water for fresh-water and sea-water adapted gills. Arrhenius plots for butanol in fresh water gills show a transition temperature at 15 °C, suggesting an increased membrane lipid fluidity above this temperature. 4. Adrenaline has no effect on Pmannitol and Pdextran, but increases Pbutanol and Pwater selectively according to the adaptation medium (+ 160% and + 100% in fresh water and + 25% and + 20% in sea water respectively). These results point to an effect of this catecholamine on the membrane lipid fluidity. PMID:439031

  2. Assessment relative soil erodibility index by rainfall simulation experiment

    NASA Astrophysics Data System (ADS)

    Diaz, Jorge; Alonso, Gustavo; Leal, Zuzell; Ruiz, María. Elena; Almoza, Yeleine; Cornelis, Wim; Gabriels, Donald

    2010-05-01

    Soil erosion in agricultural fields is identified as the main source of sediments to the Cuyaguateje River, located in the western part of Cuba. The soil is highly variable across the whole watershed and an accurate estimate of soil erodibility is difficult to asses. A rainfall simulation experiment was carrying out in 16 different soils. Plots of 5 m long by 2 m wide with similar treatments and slope ranging from 5 to 15 % were selected. A constant rainfall intensity of 120 mm/h and 60 J/m2 h of kinetic energy, for 25 minutes was applied. Runoff and sediment concentration were measured every 2 minutes. Different behavior through the rainfall event was observed denoting differences in the mechanism driving the erosion process. The total soil lost during this event is reported as a relative index of soil erodibility. There is practically no correlation between this relative index and others soil erodibility index commonly applied in literature.

  3. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false Identification of highly erodible lands criteria. 12.21 Section 12.21 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.21 Identification of highly erodible lands criteria. (a) Basis for identification as...

  4. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...) Basis for identification as highly erodible. Soil map units and an erodibility index will be used as the basis for identifying highly erodible land. The erodibility index for a soil is determined by dividing the potential average annual rate of erosion for each soil by its predetermined soil loss tolerance...

  5. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...) Basis for identification as highly erodible. Soil map units and an erodibility index will be used as the basis for identifying highly erodible land. The erodibility index for a soil is determined by dividing the potential average annual rate of erosion for each soil by its predetermined soil loss tolerance...

  6. 7 CFR 12.21 - Identification of highly erodible lands criteria.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...) Basis for identification as highly erodible. Soil map units and an erodibility index will be used as the basis for identifying highly erodible land. The erodibility index for a soil is determined by dividing the potential average annual rate of erosion for each soil by its predetermined soil loss tolerance...

  7. Increased daylength stimulates plasma growth hormone and gill Na+, K+ and -ATPase Atlantic salmon (Salmo salar )

    USGS Publications Warehouse

    McCormick, S.D.; Bjornsson, Bjorn Thrandur; Sheridan, M.; Eilertson, C.; Carey, J.B.; O'Dea, M.

    1995-01-01

    Atlantic salmon juveniles reared at constant temperature (9–10°C) were exposed to four photoperiod treatment and sampled every 2 weeks from January through May. Fish reared under normal photoperiod exhibited eight-and three fold increases in plasma growth hormone and gill Na+, K+-ATPase activity, respectively, between January and April. Fish exposed to abrupt increases in daylength (LD 15:9) in February or March responded with earlier increases in plasma growth hormone and gill Na+, K+-ATPase activity, and earlier decreases in condition factor relative to fish in the normal photoperiod group. Fish maintained under short daylength (LD 9:15) from January to May exhibited delayed and muted increases in plasma growth hormone and gill Na+, K+-ATPase activity. Plasma thyroxine exhibited a 2.5-fold increase from February to late March in the normal photoperiod group, was generally lower in the LD 9:15 group, but exhibited no obvious response to abrupt increases in daylength. There was an increase in plasma 3,5,3′-triiodo-l-thyronine with time in all groups (43–80%) but no significant response to photoperiod. Plasma levels of somatostatin-25 were highest in the LD 9:15 group, but there was no detectable response to increased daylength in any of the photoperiod treatments. The results indicate that plasma growth hormone is responsive to increased daylength and may be causally related to subsequent increases in gill Na+, K+-ATPase.

  8. A review of infectious gill disease in marine salmonid fish.

    PubMed

    Mitchell, S O; Rodger, H D

    2011-06-01

    Infectious gill diseases of marine salmonid fish present a significant challenge in salmon-farming regions. Infectious syndromes or disease conditions affecting marine-farmed salmonids include amoebic gill disease (AGD), proliferative gill inflammation (PGI) and tenacibaculosis. Pathogens involved include parasites, such as Neoparamoeba perurans, bacteria, such as Piscichlamydia salmonis and Tenacibaculum maritimum, and viruses, such as the Atlantic salmon paramyxovirus (ASPV). The present level of understanding of these is reviewed with regard to risk factors, potential impacting factors, methods of best practice to mitigate infectious gill disease, as well as knowledge gaps and avenues for future research. PMID:21401646

  9. The effect of rainstorm sequence on soil erodibility

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus Josef

    Short-term changes in soil properties, occurring over a period of days to weeks between rainstorms, affect subsequent erosional response and have been identified as major factors contributing to uncertainty in erodibility assessment. Drying-induced soil property changes are not necessarily reversed during subsequent storms, leading to rainstorm pattern-dependent erodibility dynamics. The effect of such soil climate-interaction on erodibility depends on soil properties and varies for each erosion process. This study analyses soil erodibility changes in response to varying rainstorm patterns. Four soils, different in capacity for sealing and interstorm restructuring, in four different initial conditions were selected. The varying responses of runoff development, interrill and rill erosion were examined for each soil and initial condition during laboratory experiments. The applicability of these results was assessed by field tests. Rainstorm pattern and erodibility are closely linked. Runoff development and interrill erodibility are controlled by the effect of rainfall on seal development and interstorm seal restructuring. Vulnerability to sealing and capacity for aggregation are key soil factors, while amount, frequency and intensity of rainfall and drying are the controlling climatic variables. Minimum soil resistance to rill incision was not affected by rainstorm pattern, but degree of preceding drying determined the amount of rainfall required to achieve minimum values. The effect on soil and flow conditions at incipient rill incision remain unclear due to high variability of the observed critical soil and flow properties. Effectiveness of a rainstorm to develop rills depends on the magnitude of the event, but also the degree of the preceding drying. This shows that event order plays a significant role for occurrence of rills. Occurrence of rill erosion was also influenced by the effect of previous erosion events on surface morphology and the feedback on

  10. The Endoscopic Removal of Eroded Foreign Bodies in the Ureter.

    PubMed

    Kurz, David Anthony; Mucksavage, Phillip

    2016-01-01

    A complication of using foreign materials in surgery is potential erosion into nearby tissues. The endoscopic removal of foreign bodies that have eroded into the urinary tract is a safe and minimally invasive option that has previously been described, most commonly in the bladder and urethra. We present the case of a patient who had a remote history of a pyeloplasty and was found to have different foreign bodies eroding into the ureter causing symptoms. To our knowledge, this is the first case where a patient presented with two different types of ureteral foreign body erosions that were each effectively treated endoscopically. PMID:27579409

  11. The Endoscopic Removal of Eroded Foreign Bodies in the Ureter

    PubMed Central

    Mucksavage, Phillip

    2016-01-01

    Abstract A complication of using foreign materials in surgery is potential erosion into nearby tissues. The endoscopic removal of foreign bodies that have eroded into the urinary tract is a safe and minimally invasive option that has previously been described, most commonly in the bladder and urethra. We present the case of a patient who had a remote history of a pyeloplasty and was found to have different foreign bodies eroding into the ureter causing symptoms. To our knowledge, this is the first case where a patient presented with two different types of ureteral foreign body erosions that were each effectively treated endoscopically. PMID:27579409

  12. Exposure of clownfish larvae to suspended sediment levels found on the Great Barrier Reef: Impacts on gill structure and microbiome.

    PubMed

    Hess, Sybille; Wenger, Amelia S; Ainsworth, Tracy D; Rummer, Jodie L

    2015-01-01

    Worldwide, increasing coastal development has played a major role in shaping coral reef species assemblages, but the mechanisms underpinning distribution patterns remain poorly understood. Recent research demonstrated delayed development in larval fishes exposed to suspended sediment, highlighting the need to further understand the interaction between suspended sediment as a stressor and energetically costly activities such as growth and development that are essential to support biological fitness. We examined the gill morphology and the gill microbiome in clownfish larvae (Amphiprion percula) exposed to suspended sediment concentrations (using Australian bentonite) commonly found on the inshore Great Barrier Reef. The gills of larvae exposed to 45 mg L(-1) of suspended sediment had excessive mucous discharge and growth of protective cell layers, resulting in a 56% thicker gill epithelium compared to fish from the control group. Further, we found a shift from 'healthy' to pathogenic bacterial communities on the gills, which could increase the disease susceptibility of larvae. The impact of suspended sediments on larval gills may represent an underlying mechanism behind the distribution patterns of fish assemblages. Our findings underscore the necessity for future coastal development to consider adverse effects of suspended sediments on fish recruitment, and consequently fish populations and ecosystem health. PMID:26094624

  13. Potential fate of SOC eroded from natural crusted soil surface under simulated wind driven storm

    NASA Astrophysics Data System (ADS)

    Xiao, Liangang; Fister, Wolfgang; Greenwood, Philip; Hu, Yaxian; Kuhn, Nikolaus J.

    2016-04-01

    Improving the assessment of the impact of soil erosion on carbon (C) cycling requires a better understanding of the redistribution of eroded sediment and associated soil organic carbon (SOC) across agricultural landscapes. Recent studies conducted on dry-sieved aggregates in the laboratory demonstrated that aggregation can profoundly skew SOC redistribution and its subsequent fate by accelerating settling velocities of aggregated sediment compared to mineral grains, which in turn can increase SOC mineralization into greenhouse gases. However, the erodibility of the soil in the field is more variable than in the laboratory due to tillage, crus formation, drying-wetting and freeze-thaw cycles, and biological effects. This study aimed to investigate the potential fate of the SOC eroded from naturally developed soil surface and to compare the observations with those made in the laboratory. Simulated, short, high intensity wind driven storms were conducted on a crusted loam in the field. The sediments were fractionated with a settling tube according to their potential transport distances. The soil mass, SOC concentration and cumulative 80-day CO2 emission of each fraction were identified. The results show: 1) 53% of eroded sediment and 62% of eroded SOC from the natural surface in the field would be deposited across landscapes, which is six times and three times higher compared to that implied by mineral grains, respectively; 2) the preferential deposition of SOC-rich fast-settling sediment potentially releases approximately 50% more CO2 than the same layer of the non-eroded soil; 3) the respiration of the slow-settling fraction that is potentially transported to the aquatic systems was much more active compared to the other fractions and the bulk soil. Our results confirm in general the conclusions drawn from laboratory and thus demonstrate that aggregation can affect the redistribution of sediment associated SOC under field conditions, including an increase in

  14. Isolation and characterization of bioactive fungi from shark Carcharodon carcharias' gill with biopharmaceutical prospects

    NASA Astrophysics Data System (ADS)

    Zhang, Yi; Han, Jinyuan; Feng, Yan; Mu, Jun; Bao, Haiyan; Kulik, Andreas; Grond, Stephanie

    2016-01-01

    Until recently, little was known about the fungi found in shark gills and their biomedicinal potential. In this article, we described the isolation, bioactivity, diversity, and secondary metabolites of bioactive fungi from the gill of a shark ( Carcharodon carcharias). A total of 115 isolates were obtained and grown in 12 culture media. Fifty-eight of these isolates demonstrated significant activity in four antimicrobial, pesticidal, and cytotoxic bioassay models. Four randomly selected bioactive isolates inhibited human cancer cell proliferation during re-screening. These active isolates were segregated into 6 genera using the internal transcribed spacer-large subunit (ITS-LSU) rDNA-sequence BLAST comparison. Four genera, Penicillium, Aspergillus, Mucor, and Chaetomium were the dominant taxa. A phylogenic tree illustrated their intergenera and intragenera genetic diversity. HPLC-DAD-HRMS analysis and subsequent database searching revealed that nine representative strains produced diverse bioactive compound profiles. These results detail the broad range of bioactive fungi found in a shark's gills, revealing their biopharmaceutical potential. To the best of our knowledge, this is the first study characterizing shark gill fungi and their bioactivity.

  15. Oxidative stress responses in gills of goldfish, Carassius auratus, exposed to the metribuzin-containing herbicide Sencor.

    PubMed

    Husak, Viktor V; Mosiichuk, Nadia M; Maksymiv, Ivan V; Storey, Janet M; Storey, Kenneth B; Lushchak, Volodymyr I

    2016-07-01

    Metribuzin belongs to the family of asymmetrical triazine compounds and is an active ingredient in many commercial herbicides including Sencor. Effects on goldfish (Carassius auratus L.) of exposure for 96h to 7.14, 35.7 or 71.4mgL(-1) Sencor 70 WG (corresponding to 5, 25 and 50mgL(-1) of metribuzin) were examined by evaluating oxidative stress markers and activities of antioxidant and associated enzymes in gills. Fish exposed to the lowest Sencor concentration (7.14mgL(-1)) showed a 94% increase in levels of protein carbonyls in gills as well as 45% and 144% increases in the activities of glutathione peroxidase and glutathione-S-transferase. Exposure to the highest Sencor concentration (71.4mgL(-1)) resulted in reduced levels of protein carbonyls by 56% and lipid peroxides by 40%, as compared with controls, but enhanced levels of low and high molecular mass thiols by 71% and 36%, respectively. The activities of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase were increased in gills of goldfish exposed to 71.4mgL(-1) Sencor. At any concentration tested, Sencor did not affect the activities of glutathione reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase or acetylcholine esterase in gills. The results of this study indicate that acute exposure of goldfish to Sencor had effect on free radical processes in gills and glutathione-dependent antioxidants effectively protect proteins and lipids from oxidation. PMID:27310208

  16. Quantifying intrinsic and extrinsic factors affecting soil erodibility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erodibility has traditionally been conceived as a soil dependent parameter that can be quantified from intrinsic soil properties that usually stay constant. Development of erosion prediction equations, from the empirical-based Universal Soil Loss Equation (USLE) to a more processed-based Water ...

  17. Simple Experimental Procedure for Determining WEPP Erodibility Parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Water Erosion Prediction Project (WEPP) model was developed in the USA as a process based model to simulate fluvial erosion on hillslopes. Fundamental to the model is the separation of soil erodibility into terms of interrill and rill susceptibility to erosion. Rill erosion is further divided in...

  18. Management Practices to Improve Productivity of Degraded/Eroded Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Productivity of degraded/eroded soils can be restored by using organic amendment, such as manure, and improved soil management. A study is being conducted near Hays, KS, to investigate and compare restorative potential of two nitrogen (N) sources. Dried beef manure and urea fertilizer were each appl...

  19. PROCEDURES FOR MEASURING COUGH (GILL PURGE) RATES OF FISH

    EPA Science Inventory

    The cough (gill purge) is an interruption in the normal ventilatory cycle of fish that serves to clean the gills of accumulated particulate matter. A review of the literature shows that the cough occurs in a variety of freshwater and marine fish; that both mechanical and chemical...

  20. Tracing peatland geomorphology: sediment and contaminant movements in eroding and restored systems

    NASA Astrophysics Data System (ADS)

    Shuttleworth, Emma; Evans, Martin; Hutchinson, Simon; Rothwell, James

    2015-04-01

    Peatlands are an important store of soil carbon, play a vital role in global carbon cycling, and can also act as sinks of atmospherically deposited heavy metals. However, large areas of blanket peat are significantly degraded and actively eroding as a direct result of anthropogenic pressures, which negatively impacts carbon and pollutant storage. The restoration of eroding UK peatlands is a major conservation concern, and over the last decade measures have been taken to control erosion and restore large areas of degraded peat. In severely eroded peatlands, topography is highly variable, and an appreciation of geomorphological form and process is key in understanding the controls on peatland function, and in mitigating the negative impacts of peatland erosion. The blanket peats of the Peak District, Southern Pennines, UK embody many problems and pressures faced by peatlands globally, and are amongst the most heavily eroded and contaminated in the world. The near-surface layer of the peat is contaminated by high concentrations of anthropogenically derived, atmospherically deposited heavy metals which are released into the fluvial system as a consequence of widespread erosion. Whilst not desirable, this legacy of lead pollution and its release offer a unique opportunity to trace peatland sediment movements and thus investigate the controls on sediment and contaminant mobility. A suite of established field, analytical and modelling techniques have been modified and adapted for use in peatland environments and these have been successfully employed in combination to address issues of sediment and contaminant release at a range of scales, including: (i) the development of field portable XRF to assess in situ lead concentrations in wet organic sediments; (ii) adaptation of time integrated mass flux samplers to explore spatial and temporal sediment dynamics in peatland streams; and (iii) the application of sediment source fingerprinting and numerical mixing models to

  1. Ocean warming and acidification modulate energy budget and gill ion regulatory mechanisms in Atlantic cod (Gadus morhua).

    PubMed

    Kreiss, C M; Michael, K; Lucassen, M; Jutfelt, F; Motyka, R; Dupont, S; Pörtner, H-O

    2015-10-01

    Ocean warming and acidification are threatening marine ecosystems. In marine animals, acidification is thought to enhance ion regulatory costs and thereby baseline energy demand, while elevated temperature also increases baseline metabolic rate. Here we investigated standard metabolic rates (SMR) and plasma parameters of Atlantic cod (Gadus morhua) after 3-4 weeks of exposure to ambient and future PCO2 levels (550, 1200 and 2200 µatm) and at two temperatures (10, 18 °C). In vivo branchial ion regulatory costs were studied in isolated, perfused gill preparations. Animals reared at 18 °C responded to increasing CO2 by elevating SMR, in contrast to specimens at 10 °C. Isolated gills at 10 °C and elevated PCO2 (≥1200 µatm) displayed increased soft tissue mass, in parallel to increased gill oxygen demand, indicating an increased fraction of gill in whole animal energy budget. Altered gill size was not found at 18 °C, where a shift in the use of ion regulation mechanisms occurred towards enhanced Na(+)/H(+)-exchange and HCO3 (-) transport at high PCO2 (2200 µatm), paralleled by higher Na(+)/K(+)-ATPase activities. This shift did not affect total gill energy consumption leaving whole animal energy budget unaffected. Higher Na(+)/K(+)-ATPase activities in the warmth might have compensated for enhanced branchial permeability and led to reduced plasma Na(+) and/or Cl(-) concentrations and slightly lowered osmolalities seen at 18 °C and 550 or 2200 µatm PCO2 in vivo. Overall, the gill as a key ion regulation organ seems to be highly effective in supporting the resilience of cod to effects of ocean warming and acidification. PMID:26219611

  2. Determining Relative Contributions of Eroded Landscape Sediment to the Suspended Load of Goodwin Creek Using 7Be and 210Pbxs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identifying major contributors of fine sediment to the suspended load of a streams allows for better focus of Best Management Practices. This study utilized activities of 7Be and 210Pbxs to quantify the proportion of eroded surface soils in the fine suspended sediment load of runoff events in Goodw...

  3. Adrian E. Gill 1937”1986

    NASA Astrophysics Data System (ADS)

    Clarke, Allan J.

    On April 19, Adrian Gill, FRS, my former thesis advisor and distinguished friend, died suddenly of cancer. My sadness and disbelief are more strongly felt because the life of this gifted and generous man ended so early.Born in Melbourne, Australia, Adrian was granted his Ph.D. at Cambridge University, Cambridge, U.K., in 1963. After a year at the Massachusetts Institute of Technology (Cambridge, Mass.), he returned to Cambridge in Britain, where he spent most of the rest of his life. In 1984, he left Cambridge to become director and cofounder of the Hooke Institute in Oxford, U.K. During his career he enjoyed many summers working in the United States.

  4. [Histology of gill, liver and kidney in juvenile fish Colossoma macropomum exposed to three temperatures].

    PubMed

    Rojas, Luz-Marina; Mata, Claunis; Oliveros, Aridays; Salazar-Lugo, Raquel

    2013-06-01

    Abstract: Histology of gill, liver and kidney in juvenile fish Colossoma macropomum exposed to three temperatures. Water temperature is an important factor that affects growth and antioxidant enzyme activities in fish, and when adverse, it may trigger diseases in fish populations. C. macropomum is a freshwater neotropical fish widely distributed in South America and abundant in river basins as the Amazon and Orinoco. It is highly used for intensive aquaculture development and is a very important product for the local riverside economy in Venezuela. The purpose of our study was to examine the water temperature effect on gills, liver and kidneys of juvenile fishes of C macropomum. Eighteen juveniles with biometrical index of 17.87 +/- 7.88 cm and 87.69 +/- 34.23 g were respectively exposed to three culture temperatures (T18, T29 and T35 degrees C) during a period of 21 days. Histological analyses on gills, liver and kidney were made according to standard methodologies. Our results showed that these tissues exhibited normal citoarchitecture at T29. On the contrary, T18-gills displayed brachiallipid droplets inside brachial epithelium; and disorganization in the brachial tissue was observed at T35. Furthermore, we observed two kinds of hepatocytes (dark and light) on T180 degrees C-liver. The T35-liver samples showed cytoplasmatic granulation and damages in cytoplasmatic membrane. Kidney samples from T18 observed alterations in the cellular distribution of the hematopoietic tissue; while, at T35, the most important feature observed was the disorganization of the glomerular structure. We concluded that T18 and T35 are respectively critical and severe temperatures to C. macropomum; besides, the most sensible tissues to changes induced by temperature in this species were the liver and gills. PMID:23885590

  5. Chromosomal damage and EROD induction in tree swallows (Tachycineta bicolor) along the Upper Mississippi River, Minnesota, USA.

    PubMed

    Bigorgne, Emilie; Custer, Thomas W; Dummer, Paul M; Erickson, Richard A; Karouna-Renier, Natalie; Schultz, Sandra; Custer, Christine M; Thogmartin, Wayne E; Matson, Cole W

    2015-07-01

    The health of tree swallows, Tachycineta bicolor, on the Upper Mississippi River (UMR) was assessed in 2010 and 2011 using biomarkers at six sites downriver of Minneapolis/St. Paul, MN metropolitan area, a tributary into the UMR, and a nearby lake. Chromosomal damage was evaluated in nestling blood by measuring the coefficient of variation of DNA content (DNA CV) using flow cytometry. Cytochrome P450 1A activity in nestling liver was measured using the ethoxyresorufin-O-dealkylase (EROD) assay, and oxidative stress was estimated in nestling livers via determination of thiobarbituric acid reacting substances (TBARS), reduced glutathione (GSH), oxidized glutathione (GSSG), the ratio GSSG/GSH, total sulfhydryl, and protein bound sulfhydryl (PBSH). A multilevel regression model (DNA CV) and simple regressions (EROD and oxidative stress) were used to evaluate biomarker responses for each location. Chromosomal damage was significantly elevated at two sites on the UMR (Pigs Eye and Pool 2) relative to the Green Mountain Lake reference site, while the induction of EROD activity was only observed at Pigs Eye. No measures of oxidative stress differed among sites. Multivariate analysis confirmed an increased DNA CV at Pigs Eye and Pool 2, and elevated EROD activity at Pigs Eye. These results suggest that the health of tree swallows has been altered at the DNA level at Pigs Eye and Pool 2 sites, and at the physiological level at Pigs Eye site only. PMID:25777616

  6. Chromosomal damage and EROD induction in tree swallows (Tachycineta bicolor) along the Upper Mississippi River, Minnesota, USA

    USGS Publications Warehouse

    Emilie Bigorgne; Custer, Thomas W.; Dummer, Paul; Erickson, Richard A.; Karouna, Natalie; Schultz, Sandra; Custer, Christine M.; Thogmartin, Wayne E.; Cole W. Matson

    2015-01-01

    The health of tree swallows, Tachycineta bicolor, on the Upper Mississippi River (UMR) was assessed in 2010 and 2011 using biomarkers at six sites downriver of Minneapolis/St. Paul, MN metropolitan area, a tributary into the UMR, and a nearby lake. Chromosomal damage was evaluated in nestling blood by measuring the coefficient of variation of DNA content (DNA CV) using flow cytometry. Cytochrome P450 1A activity in nestling liver was measured using the ethoxyresorufin-O-dealkylase (EROD) assay, and oxidative stress was estimated in nestling livers via determination of thiobarbituric acid reacting substances (TBARS), reduced glutathione (GSH), oxidized glutathione (GSSG), the ratio GSSG/GSH, total sulfhydryl, and protein bound sulfhydryl (PBSH). A multilevel regression model (DNA CV) and simple regressions (EROD and oxidative stress) were used to evaluate biomarker responses for each location. Chromosomal damage was significantly elevated at two sites on the UMR (Pigs Eye and Pool 2) relative to the Green Mountain Lake reference site, while the induction of EROD activity was only observed at Pigs Eye. No measures of oxidative stress differed among sites. Multivariate analysis confirmed an increased DNA CV at Pigs Eye and Pool 2, and elevated EROD activity at Pigs Eye. These results suggest that the health of tree swallows has been altered at the DNA level at Pigs Eye and Pool 2 sites, and at the physiological level at Pigs Eye site only.

  7. Immunolocalization of chloride transporters to gill epithelia of euryhaline teleosts with opposite salinity-induced Na+/K+-ATPase responses.

    PubMed

    Tang, Cheng-Hao; Hwang, Lie-Yueh; Shen, I-Da; Chiu, Yu-Hui; Lee, Tsung-Han

    2011-12-01

    Opposite patterns of branchial Na(+)/K(+)-ATPase (NKA) responses were found in euryhaline milkfish (Chanos chanos) and pufferfish (Tetraodon nigroviridis) upon salinity challenge. Because the electrochemical gradient established by NKA is thought to be the driving force for transcellular Cl(-) transport in fish gills, the aim of this study was to explore whether the differential patterns of NKA responses found in milkfish and pufferfish would lead to distinct distribution of Cl(-) transporters in their gill epithelial cells indicating different Cl(-) transport mechanisms. In this study, immunolocalization of various Cl(-) transport proteins, including Na(+)/K(+)/2Cl(-) cotransporter (NKCC), cystic fibrosis transmembrane conductance regulator (CFTR), anion exchanger 1 (AE1), and chloride channel 3 (ClC-3), were double stained with NKA, the basolateral marker of branchial mitochondrion-rich cells (MRCs), to reveal the localization of these transporter proteins in gill MRC of FW- or SW-acclimated milkfish and pufferfish. Confocal microscopic observations showed that the localization of these transport proteins in the gill MRCs of the two studied species were similar. However, the number of gill NKA-immunoreactive (IR) cells in milkfish and pufferfish exhibited to vary with environmental salinities. An increase in the number of NKA-IR cells should lead to the elevation of NKA activity in FW milkfish and SW pufferfish. Taken together, the opposite branchial NKA responses observed in milkfish and pufferfish upon salinity challenge could be attributed to alterations in the number of NKA-IR cells. Furthermore, the localization of these Cl(-) transporters in gill MRCs of the two studied species was identical. It depicted the two studied euryhaline species possess the similar Cl(-) transport mechanisms in gills. PMID:21336594

  8. Gill Na(+), K(+)-ATPase in a series of hyper-regulating gammarid amphipods: enzyme characterisation and the effects of salinity acclimation.

    PubMed

    Brooks, Steven J; Lloyd Mills, Chris

    2006-05-01

    The enzyme Na(+), K(+)-ATPase was investigated in the gills of selected hyper-regulating gammarid amphipods. Gill Na(+), K(+)-ATPase was characterised with respect to the main cation and co-factor concentrations for the freshwater amphipod Gammarus pulex. The optimum cation and co-factor concentrations for maximal gill Na(+), K(+)-ATPase activity in G. pulex were 100mM Na(+), 15mM K(+), 15mM Mg(2+) and 5mM ATP, at pH 7.2. The effects of salinity acclimation on gill Na(+), K(+)-ATPase activity and haemolymph sodium concentrations was investigated in selected gammarid amphipods from different salinity environments. Maximal enzyme activity occurred in all gammarids when acclimated to the most dilute media. This maximal activity coincided with the largest sodium gradient between the haemolymph and the external media. As the haemolymph/medium sodium gradient decreased, a concomitant reduction in gill Na(+), K(+)-ATPase activity occurred. This implicates the involvement of gill Na(+), K(+)-ATPase in the active uptake of sodium from dilute media in hyper-regulating gammarids. PMID:16516515

  9. Trace metals in gills of fish from the Arabian Gulf

    SciTech Connect

    Al-Yakoob, S.; Bahloul, M. ); Bou-Olayan, A.H.

    1994-11-01

    Complexation of metals by coordinate linkages with appropriate organic molecules in biological tissues is an important process involved in metal accumulation by aquatic organisms. Fish respiratory systems differ from all other systems because damage to gills has immediate impacts on the rest of the fish's body. Veer et al. observed significant correlation between gill-metal concentration and whole-body weight. More nickel is accumulated in gill tissue of the catfish (Clarias batrachus) than in the liver or intestine. More cadmium is accumulated in gill tissue of the fish Heteropneustes fossilis (Bloch) and Channa punctatus (Bloch) than in the liver or kidney. When exposed to lethal and sublethal concentrations of copper, gills of the freshwater fish Labeo rohita (Hamilton) showed the highest degree of copper accumulation. Petroleum and petrochemical industry wastes contribute significantly to metal enrichment of the Arabian Gulf marine environment. Because accumulation of metal ions is significant in gills, levels of Cd, Cr, Cu, Ni and Pb were investigated in gills of fish from potentially impacted areas along the western side of the Arabian Gulf after the 1991 oil-spill. 15 refs., 3 figs., 1 tab.

  10. Motor-Cortical Interaction in Gilles de la Tourette Syndrome

    PubMed Central

    Franzkowiak, Stephanie; Pollok, Bettina; Biermann-Ruben, Katja; Südmeyer, Martin; Paszek, Jennifer; Thomalla, Götz; Jonas, Melanie; Orth, Michael; Münchau, Alexander; Schnitzler, Alfons

    2012-01-01

    Background In Gilles de la Tourette syndrome (GTS) increased activation of the primary motor cortex (M1) before and during movement execution followed by increased inhibition after movement termination was reported. The present study aimed at investigating, whether this activation pattern is due to altered functional interaction between motor cortical areas. Methodology/Principal Findings 10 GTS-patients and 10 control subjects performed a self-paced finger movement task while neuromagnetic brain activity was recorded using Magnetoencephalography (MEG). Cerebro-cerebral coherence as a measure of functional interaction was calculated. During movement preparation and execution coherence between contralateral M1 and supplementary motor area (SMA) was significantly increased at beta-frequency in GTS-patients. After movement termination no significant differences between groups were evident. Conclusions/Significance The present data suggest that increased M1 activation in GTS-patients might be due to increased functional interaction between SMA and M1 most likely reflecting a pathophysiological marker of GTS. The data extend previous findings of motor-cortical alterations in GTS by showing that local activation changes are associated with alterations of functional networks between premotor and primary motor areas. Interestingly enough, alterations were evident during preparation and execution of voluntary movements, which implies a general theme of increased motor-cortical interaction in GTS. PMID:22238571

  11. Prolactin and cortisol mediate the maintenance of hyperosmoregulatory ionocytes in gills of Mozambique tilapia: Exploring with an improved gill incubation system.

    PubMed

    Watanabe, Soichi; Itoh, Kohei; Kaneko, Toyoji

    2016-06-01

    Endocrine control of osmoregulation is essential for teleosts to adapt to various aquatic environments. Prolactin (PRL) is known as a fundamental endocrine factor for hyperosmoregulation in teleost fishes, acting on ionocytes in the gills to maintain ion concentrations of body fluid within narrow physiological ranges in freshwater conditions. Cortisol is also known as an osmoregulation-related steroid in teleosts; however, its precise function is still controversial. Here, we investigated more detailed effects of PRL and roles of cortisol on ionocytes of Mozambique tilapia (Oreochromis mossambicus) in freshwater, using an improved gill filament incubation system. This incubation system resulted in enhanced cell viability, as evaluated using the dead cell marker propidium iodide. PRL was shown to maintain the density of freshwater-type ionocytes in isolated gill filaments; this effect of PRL is not achieved by the activation of cell proliferation, but by the maintenance of existing ionocytes. Cortisol alone did not show any distinct effect on ionocyte density in isolated gill filaments. We also assessed effects of PRL and cortisol on relative mRNA levels of NCC2, NHE3, NKAa1a, and NKAa1b. PRL maintained relative NCC2 and NKAa1a mRNA abundance, and cortisol showed a stimulatory effect on relative NCC2 and NKAa1a mRNA levels in combination with PRL, though cortisol alone exerted no effect on these genes. An increase in NKAa1b mRNA abundance was detected in cortisol-treated groups. PRL treatment also maintained normal NCC2 localization at the apical membrane of the ionocytes. These results indicate that PRL maintains freshwater-type ionocytes, and that cortisol stimulates the function of ionocytes maintained by PRL. PMID:27118703

  12. Analysis of reactive oxygen species, Ca²+ , and Hsp70 in the gill and mantle of clams Ruditapes philippinarum exposed in cadmium.

    PubMed

    Liu, Dongwu; Chen, Zhiwei; Liu, Zhenxing

    2013-12-01

    In this study, the probes 2',7'-dichlorofluorescein diacetate (H2 DCF-DA) and Fluo-3 AM were used to investigate the instantaneous change of reactive oxygen species (ROS) and Ca(2+) in the gill and mantle of clams Ruditapes philippinarum exposed in 0.05 mg L(-1) Cd(2+) with the laser-scanning confocal microscopy. The results indicated that Ca(2+) level was declined in the gill and slightly increased in the mantle. The level of ROS was declined in the gill, while the oscillation of ROS level was observed in the mantle. These data revealed that Ca(2+) could stimulate mitochondrial activity and enhance the respiratory chain in the gill and mantle. In addition, the expression of Hsp70 was increased in the gill and mantle of clams exposed in 0.05 mg L(-1) Cd(2+) . The change of Ca(2+) and ROS level affected the expression of Hsp70 in the gill and mantle. An appropriate method was established to analyze the effects of Cd(2+) on ROS, Ca(2+) , and Hsp70 in the gill and mantle of clams with confocal microscopy. Both confocal microscopy and chemical fluorescent are valuable tools for measurement of time-dependent intracellular ROS and Ca(2+) signals. PMID:24166874

  13. Abrasion of eroded root dentine brushed with different toothpastes.

    PubMed

    De Menezes, Márcio; Turssi, Cecilia Pedroso; Hara, Anderson Takeo; Messias, Danielle Cristine Furtado; Serra, Mônica Campos

    2004-09-01

    This study evaluated the surface roughness change and wear provided by different dentifrices on root dentine previously exposed to erosive challenges. According to a randomized complete block design, 150 slabs of bovine root dentine (6 x 3 x 2 mm) were ground flat and polished. In an area of 4 x 3 mm on the dentine surface, specimens were submitted to five erosive/abrasive events, each one composed by: exposure to Sprite Diet or distilled water for 5 min, then to a remineralizing solution for 1 min, and simulation of 5,000 brushing strokes. Four dentifrices--regular (RE), baking soda (BS), whitening (WT) and tartar control (TC)--and distilled water (CO), used as control, were compared. Final texture and the wear depth were evaluated using a profilometer. ANOVA did not show significant interaction, indicating that the effect of dentifrices on both surface roughness change and wear did not depend on whether or not the dentine was eroded ( p>0.05). There was no difference between abrasion of eroded and sound dentine. The Tukey's test revealed that WT, BS and TC provided the highest increase in surface roughness differing from RE and CO. TC yielded the deepest wear of root dentine, whereas RE and CO, the shallowest. No significant difference in wear among BS, TC and WT were observed. Within the limitations of this study, the data showed that abrasion of both eroded and sound root dentine was dependent on the dentifrice used. PMID:15146320

  14. Mass spectrometry data from a quantitative analysis of protein expression in gills of immuno-challenged blue mussels (Mytilus edulis).

    PubMed

    Hörnaeus, K; Guillemant, J; Mi, J; Hernroth, B; Bergquist, J; Lind, S Bergström

    2016-09-01

    Here, we provide the dataset associated with our research article on the potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, "Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis)" [1]. Blue mussels were stimulated with lipopolysaccharides and samples were collected at different time points post injection. Protein extracts were prepared from the gills, digested using trypsin and a full in-depth proteome investigation was performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Protein identification and quantification was performed using the MaxQuant 1.5.1.2 software, "MaxQuant enables high peptide identification rates, individualized p.p.b.-range mass accuracies and proteome-wide protein quantification" [2]. PMID:27358907

  15. Sorption and dissipation of aged metolachlor residues in eroded and rehabilitated soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To accurately determine availability for offsite transport, sorption and dissipation of aged metolachlor were characterized in rehabilitated and eroded prairie soils using sequential batch slurry and accelerated solvent extraction (ASE). In the eroded upper slope, soil-landscape rehabilitation more ...

  16. 75 FR 75961 - Notice of Implementation of the Wind Erosion Prediction System for Soil Erodibility System...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-07

    ... Soil Erodibility System Calculations for the Natural Resources Conservation Service AGENCY: Natural...) for soil erodibility system calculations scheduled for implementation for public review and comment... computer model that predicts soil erosion via simulation of the fundamental processes controlling...

  17. PAH metabolites, GST and EROD in European eel (Anguilla anguilla) as possible indicators for eel habitat quality in German rivers.

    PubMed

    Kammann, Ulrike; Brinkmann, Markus; Freese, Marko; Pohlmann, Jan-Dag; Stoffels, Sandra; Hollert, Henner; Hanel, Reinhold

    2014-02-01

    The stock of the European eel (Anguilla anguilla L.) continues to decline and has reached a new minimum in 2011. Poor health status of the spawners due to organic contaminants is one of the possible causes for this dramatic situation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants, which are rapidly metabolized in vertebrates. EROD (ethoxyresorufin-O-deethylase) and GST (glutathione-S-transferase) are two enzymes involved in PAH detoxification in fish. In this study, PAH metabolites as well as EROD and GST activity in a large, comprising dataset of more than 260 migratory and pre-migratory eels from five large German river basin districts were used to describe PAH exposure and its metabolism as possible indicators for the habitat quality for eels. Eel from the river Elbe appear to be moderately contaminated with PAH. Highest mean values of PAH metabolites were analysed in fish from the river Rhine. However, the results suggest that contaminants such as PAH are metabolized in the fish and may have contributed to EROD activity in eels caught from the Elbe estuary to 600 km upstream. Since the eel's onset of cessation of feeding is closely linked to maturation and migration, we propose bile pigments as new indicators contributing to identify the proportion of migratory eel, which is crucial information for eel management plans. We showed that PAH metabolites normalized to bile pigments as well as EROD could be used to describe the habitat quality and might be suitable parameters in search for suitable stocking habitats. PMID:24085514

  18. Characterizing Phosphorus in Eroding Streambank Soils in Chittenden County, Vermont

    NASA Astrophysics Data System (ADS)

    Ross, D. S.; Ishee, E. R.

    2011-12-01

    Lake Champlain has had persistent algal blooms associated with excess phosphorus (P) from the landscape. Streambank erosion is ubiquitous throughout the Champlain Basin with 75% of Vermont stream reaches classified as unstable. The P contribution of streambank erosion has not been well quantified, yet could be a significant source of non-point P. The objectives of this study were to 1) assess the variability in total P (TP) and soil test P (MM-P) for eroding riparian soils; 2) relate TP and MM-P with soil physical and chemical properties, including texture, Al, Ca, and Fe; 3) relate TP and MM-P to landscape parameters, including land use/land cover (LULC), landscape position, soil type and parent material; and 4) quantify the potential P load from eroding streambanks. Soil samples were taken from 76 erosion features to a depth of 90 cm on 4 streams in Chittenden County, Vermont. Samples were analyzed for texture, total P, Modified-Morgan's P, and total aluminum, calcium, iron, and manganese. A subset of samples was extracted with acid ammonium oxalate to estimate the degree of P saturation. Landscape parameters were assessed using available spatial databases for LULC, parent material, soil type, landscape position. Mean concentrations of TP and MM-P were similar among the four streams and through depth, but not correlated with each other. A strong relationship existed between Ca and TP in excess of apatite ratios suggesting apatite-P is a common P form in these soils. Low MM-P concentrations and oxalate results indicate that eroded streambank soil may act as a sink rather than a source of P. Landscape parameters including LULC and landscape position correlated with TP and MM-P. Streambank erosion from four streams in Chittenden County contributed a total of 11.2 to 14.1 MT of TP and 37.7 kg of MM-P to corresponding stream corridors. Estimated potential P load from eroding streambanks was equivalent to 50 to 60% of total non-point P load. Streambank soils may

  19. Does Aggregation Affect the Redistribution and Quality of Eroded SOC?

    NASA Astrophysics Data System (ADS)

    Hu, Yaxian; Kuhn, Nikolaus

    2015-04-01

    A substantial amount of literature has discussed the impacts of soil erosion on global carbon cycling. However, numerous gaps in our knowledge remain unaddressed, for instance, the biogeochemical fate of displaced SOC during transport being one of them. The transport distance and the quality of eroded SOC are the two major factors that determine its fate. Previous laboratory-based research had demonstrated that the effects of aggregation can potentially shorten the transport distance of eroded SOC. The mineralization potential of SOC also differs in sediment fractions of different likely transport distances. It is therefore essential to examine the transport distance and quality of eroded SOC under field conditions with natural rainfall as the agent of erosion. Soil samples from a silty clay soil from Switzerland and a sandy soil from Denmark, were collected in the field this summer after natural rainfall events. The soil from Switzerland was sampled from a field of maize in St. Ursanne (47°20' N 7°09' E) on August 6th, 2014 after a natural rainfall event. A depositional fan consisting of aggregated sediment was formed outside the lower edge of the field. The sandy soil from Denmark was sampled from a farm in Foulum (56°30' N, 9°35' W) on September 4, 2014, after a series of natural rainfall events. Soil samples were collected at different topographic positions along the two slopes. All the soil samples from the two farms were fractionated by a settling tube. Bulk soil from Switzerland and Denmark was also dispersed by ultrasound. The SOC contents of all bulk soils and associated fractions were determined using a carbon analyzer Leco 612 at 1000°C. The quality of SOC in different settling fractions collected from various topographic positions were also determined by stable isotopes of C and N (13C and 15N). Our results show that 1) the aggregate specific SOC distribution evidently differs from the mineral particle specific SOC distribution, indicating that re

  20. Glutathione Transferases Responses Induced by Microcystin-LR in the Gills and Hepatopancreas of the Clam Venerupis philippinarum

    PubMed Central

    Carneiro, Mariana; Reis, Bruno; Azevedo, Joana; Campos, Alexandre; Osório, Hugo; Vasconcelos, Vítor; Martins, José Carlos

    2015-01-01

    A multi-method approach was employed to compare the responses of Glutatione Transferases (GSTs) in the gills and hepatopancreas of Venerupis philippinarum to microcystins (MCs) toxicity. In this way, using the cytosolic fraction, the enzymatic activity of GSTs, superoxide dismutase (SOD), serine/threonine protein phosphatases (PPP2) along with the gene expression levels of four GST isoforms (pi, mu, sigma1, sigma2) were investigated in both organs of the clams exposed for 24 h to 10, 50 and 100 μg L−1 of MC-LR. Cytosolic GSTs (cGSTs) from both organs of the high dose exposed clams were purified by glutathione-agarose affinity chromatography, characterized kinetically and the changes in the expression of cGSTs of the gills identified using a proteomic approach. MC-LR caused an increase in GST enzyme activity, involved in conjugation reactions, in both gills and hepatopancreas (100 μg L−1 exposure). SOD activity, an indicator of oxidative stress, showed significantly elevated levels in the hepatopancreas only (50 and 100 μg L−1 exposure). No significant changes were found in PPP2 activity, the main target of MCs, for both organs. Transcription responses revealed an up-regulation of sigma2 in the hepatopancreas at the high dose, but no significant changes were detected in the gills. Kinetic analysis evidenced differences between gills of exposed and non-exposed extracts. Using proteomics, qualitative and quantitative differences were found between the basal and inducible cGSTs. Overall, results suggest a distinct role of GST system in counteracting MCs toxicity between the gills and the hepatopancreas of V. philippinarum, revealing different roles between GST isoforms within and among both organs. PMID:26067368

  1. Gill transcriptome response to changes in environmental calcium in the green spotted puffer fish

    PubMed Central

    2010-01-01

    Background Calcium ion is tightly regulated in body fluids and for euryhaline fish, which are exposed to rapid changes in environmental [Ca2+], homeostasis is especially challenging. The gill is the main organ of active calcium uptake and therefore plays a crucial role in the maintenance of calcium ion homeostasis. To study the molecular basis of the short-term responses to changing calcium availability, the whole gill transcriptome obtained by Super Serial Analysis of Gene Expression (SuperSAGE) of the euryhaline teleost green spotted puffer fish, Tetraodon nigroviridis, exposed to water with altered [Ca2+] was analysed. Results Transfer of T. nigroviridis from 10 ppt water salinity containing 2.9 mM Ca2+ to high (10 mM Ca2+ ) and low (0.01 mM Ca2+) calcium water of similar salinity for 2-12 h resulted in 1,339 differentially expressed SuperSAGE tags (26-bp transcript identifiers) in gills. Of these 869 tags (65%) were mapped to T. nigroviridis cDNAs or genomic DNA and 497 (57%) were assigned to known proteins. Thirteen percent of the genes matched multiple tags indicating alternative RNA transcripts. The main enriched gene ontology groups belong to Ca2+ signaling/homeostasis but also muscle contraction, cytoskeleton, energy production/homeostasis and tissue remodeling. K-means clustering identified co-expressed transcripts with distinct patterns in response to water [Ca2+] and exposure time. Conclusions The generated transcript expression patterns provide a framework of novel water calcium-responsive genes in the gill during the initial response after transfer to different [Ca2+]. This molecular response entails initial perception of alterations, activation of signaling networks and effectors and suggests active remodeling of cytoskeletal proteins during the initial acclimation process. Genes related to energy production and energy homeostasis are also up-regulated, probably reflecting the increased energetic needs of the acclimation response. This study is the

  2. Gill Na+-K+-2Cl- cotransporter abundance and location in Atlantic salmon: Effects of seawater and smolting

    USGS Publications Warehouse

    Pelis, R.M.; Zydlewski, J.; McCormick, S.D.

    2001-01-01

    Na+-K+-2Cl- cotransporter abundance and location was examined in the gills of Atlantic salmon (Salmo salar) during seawater acclimation and smolting. Western blots revealed three bands centered at 285, 160, and 120 kDa. The Na+-K+-2Cl- cotransporter was colocalized with Na+-K+-ATPase to chloride cells on both the primary filament and secondary lamellae. Parr acclimated to 30 parts per thousand seawater had increased gill Na+-K+-2Cl- cotransporter abundance, large and numerous Na+-K+-2Cl- cotransporter immunoreactive chloride cells on the primary filament, and reduced numbers on the secondary lamellae. Gill Na+-K+-2Cl- cotransporter levels were low in presmolts (February) and increased 3.3-fold in smolts (May), coincident with elevated seawater tolerance. Cotransporter levels decreased below presmolt values in postsmolts in freshwater (June). The size and number of immunoreactive chloride cells on the primary filament increased threefold during smolting and decreased in postsmolts. Gill Na+-K+-ATPase activity and Na+-K+-2Cl- cotransporter abundance increased in parallel during both seawater acclimation and smolting. These data indicate a direct role of the Na+-K+-2Cl- cotransporter in salt secretion by gill chloride cells of teleost fish.

  3. Site-scale variability of streambank fluvial erodibility parameters as measured with a jet erosion test

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The erosion rate of cohesive streambanks is typically modeled using the excess shear stress equation, dependent on two erodibility parameters: critical shear stress and erodibility coefficient. The Jet Erosion Test (JET) has become the most common method for estimating these erodibility parameters ...

  4. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 1 2013-01-01 2013-01-01 false NRCS responsibilities regarding highly erodible land. 12.20 Section 12.20 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding...

  5. 7 CFR 760.821 - Compliance with highly erodible land and wetland conservation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Compliance with highly erodible land and wetland... Disaster Program § 760.821 Compliance with highly erodible land and wetland conservation. (a) The highly erodible land and wetland conservation provisions of part 12 of this title apply to the receipt of...

  6. 7 CFR 760.821 - Compliance with highly erodible land and wetland conservation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 7 2013-01-01 2013-01-01 false Compliance with highly erodible land and wetland... Disaster Program § 760.821 Compliance with highly erodible land and wetland conservation. (a) The highly erodible land and wetland conservation provisions of part 12 of this title apply to the receipt of...

  7. 7 CFR 760.821 - Compliance with highly erodible land and wetland conservation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 7 2012-01-01 2012-01-01 false Compliance with highly erodible land and wetland... Disaster Program § 760.821 Compliance with highly erodible land and wetland conservation. (a) The highly erodible land and wetland conservation provisions of part 12 of this title apply to the receipt of...

  8. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 1 2011-01-01 2011-01-01 false NRCS responsibilities regarding highly erodible land. 12.20 Section 12.20 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding...

  9. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 1 2012-01-01 2012-01-01 false NRCS responsibilities regarding highly erodible land. 12.20 Section 12.20 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding...

  10. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 1 2014-01-01 2014-01-01 false NRCS responsibilities regarding highly erodible land. 12.20 Section 12.20 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding...

  11. 7 CFR 760.821 - Compliance with highly erodible land and wetland conservation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 7 2014-01-01 2014-01-01 false Compliance with highly erodible land and wetland... Disaster Program § 760.821 Compliance with highly erodible land and wetland conservation. (a) The highly erodible land and wetland conservation provisions of part 12 of this title apply to the receipt of...

  12. 7 CFR 760.821 - Compliance with highly erodible land and wetland conservation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 7 2011-01-01 2011-01-01 false Compliance with highly erodible land and wetland... Disaster Program § 760.821 Compliance with highly erodible land and wetland conservation. (a) The highly erodible land and wetland conservation provisions of part 12 of this title apply to the receipt of...

  13. 7 CFR 12.20 - NRCS responsibilities regarding highly erodible land.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 1 2010-01-01 2010-01-01 false NRCS responsibilities regarding highly erodible land. 12.20 Section 12.20 Agriculture Office of the Secretary of Agriculture HIGHLY ERODIBLE LAND AND WETLAND CONSERVATION Highly Erodible Land Conservation § 12.20 NRCS responsibilities regarding...

  14. The metabolic effects of limbic leucotomy in Gilles de la Tourette syndrome.

    PubMed Central

    Sawle, G V; Lees, A J; Hymas, N F; Brooks, D J; Frackowiak, R S

    1993-01-01

    Regional cerebral oxygen metabolism was measured before and after limbic leucotomy in a patient with Gilles de la Tourette syndrome, obsessive compulsive disorder, and obsessional slowness. The preoperative scan showed hypermetabolism in the caudate nuclei, which normalised after operation. It is proposed that the beneficial effects of this operation on both tics and obsessive compulsive behaviour are mediated by disruption of abnormal neural activity in basal ganglia-thalamocortical loops. Images PMID:8410025

  15. The Symptomatology and Diagnosis of Gilles de la Tourette's Syndrome

    ERIC Educational Resources Information Center

    Shapiro, Arthur; And Others

    1973-01-01

    The symptomatology of 34 patients with Gilles de la Tourette's syndrome was described in detail. The purpose was to clarify the diagnostic criteria for Tourette's syndrome by describing the type, variety, and frequency of symptoms in this illness. (Author)

  16. 20. Historic American Buildings Survey M. Diggs, Draftsman of Gill ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. Historic American Buildings Survey M. Diggs, Draftsman of Gill and Mead, Architects September 20, 1907 ORIGINAL DRAWING OF ROOF DETAILS From the Collection of Mr. Allan Klauber - Melville Klauber House, 3060 Sixth Avenue, San Diego, San Diego County, CA

  17. McGill's Integrated Civil and Common Law Program.

    ERIC Educational Resources Information Center

    Morissette, Yves-Marie

    2002-01-01

    Describes the bijural program of McGill University Faculty of Law. The program educates all first-degree law students in both the common law and civil law traditions, preparing them for the increasing globalization of legal practice. (EV)

  18. Gill trematodes (flukes) in wild-caught killifish (Fundulus heteroclitus).

    PubMed

    Goulding, David R; Blankenship-Paris, Terry L; Lewbart, Gregory A; Myers, Page H; Demianenko, Tracy K; Clark, James A; Forsythe, Diane B

    2004-03-01

    Three wild caught killifish (Fundulus heteroclitus) on an Institutional Animal Care and Use Committee-approved protocol were found dead within 2 days after being received. The fish were housed in two separate aquaria. Aquarium water was evaluated, and pH, salinity, ammonia, nitrate, and nitrite levels were within acceptable parameters. Several remaining fish appeared to be slow-moving and were presented for necropsy. Multiple, scattered, ulcerated skin lesions (diameter, 1 to 5 mm) were noted at necropsy and were cultured. No pathogenic bacteria were isolated. Wet-mount samples of the gills revealed multiple cysts at the gill margins, each containing a motile organism. No other gill parasites were detected. A diagnosis of trematodiasis was made. The cysts were identified as encysted metacercariae of a digenetic trematode. We surmise that the large numbers of gill flukes combined with the stress of recent shipment likely caused the observed morbidity and mortality. PMID:15053506

  19. Correction factors for the directional response of Gill propeller anemometers

    NASA Astrophysics Data System (ADS)

    Bowen, A. J.; Teunissen, H. W.

    1986-12-01

    This note briefly summarizes some recent wind-tunnel tests carried out at the Atmospheric Environment Service, Canada, to investigate the directional response of Gill (1975) propeller anemometers with two specific models of propeller. Tables of optimum noncosine-response correction factors are presented for both propeller types, and results of some field intercomparisons between the Gill and sonic anemometer measurements of turbulence statistics are summarized.

  20. Slope evolution at the Calvert Cliffs, Maryland -- measuring the change from eroding bluffs to stable slopes

    USGS Publications Warehouse

    Herzog, Martha; Larsen, Curtis E.; McRae, Michele

    2002-01-01

    Despite a long history of geomorphic studies, it is difficult to ascertain the time required for slopes to change from near vertical exposures to relatively stable slopes due to inadequate age control. Actively eroding coastal bluffs along the western shore of the Chesapeake Bay provide a key for understanding the centennial-scale development of stable slopes from eroding bluff faces. The Calvert Cliffs are composed of sandy silts, silty sands, and clayey silts of Miocene-age. Active wave erosion at the bluff toes encourages rapid sloughing from bluff faces and maintains slope angles of 70-80 degrees and relatively constant bluff-retreat rates. Naturally stabilized slopes are preserved as a fossil bluff line inland from a prograding cuspate foreland at Cove Point. The foreland is migrating southward at a rate of ca. 1.5 m/yr. As it moves south, it progressively protects bluffs from wave action as new beaches are deposited at their toes. Wave erosion is reinitiated at the northern end of the complex as the landform passes. An incremental record of slope change is preserved along the fossil bluff line. 14C dating of swales between beach ridges shows the complex to span 1700 years of progressive migration history. We hypothesized that slopes would change from steep, eroding faces to low-angle slopes covered with vegetation and sought to document the rate of change. Our team measured slope angles at intervals along the fossil bluff line and dated profiles by interpolating 14C ages of adjacent beach ridges. There was no progressive decrease in slope with age. All slopes along the fossil bluff line were 30-40 degrees with a mean of 35 degrees. Constancy in slope angle suggests that steep, actively eroding bluffs were quickly changed to stable slopes by landslides and slumping once they were protected. Given the accuracy of our age control, we conclude that the time required to attain a stable slope under natural processes is less than one century. This indicates that

  1. Dynamic replacement and loss of soil carbon on eroding cropland

    USGS Publications Warehouse

    Harden, J.W.; Sharpe, J.M.; Parton, W.J.; Ojima, D.S.; Fries, T.L.; Huntington, T.G.; Dabney, S.M.

    1999-01-01

    Links between erosion/sedimentation history and soil carbon cycling were examined in a highly erosive setting in Mississippi loess soils. We sampled soils on (relatively) undisturbed and cropped hillslopes and measured C, N, 14C, and CO2 flux to characterize carbon storage and dynamics and to parameterize Century and spreadsheet 14C models for different erosion and tillage histories. For this site, where 100 years of intensive cotton cropping were followed by fertilization and contour plowing, there was an initial and dramatic decline in soil carbon content from 1870 to 1950, followed by a dramatic increase in soil carbon. Soil erosion amplifies C loss and recovery: About 100% of the original, prehistoric soil carbon was likely lost over 127 years of intensive land use, but about 30% of that carbon was replaced after 1950. The eroded cropland was therefore a local sink for CO2 since the 1950s. However, a net CO2 sink requires a full accounting of eroded carbon, which in turn requires that decomposition rates in lower slopes or wetlands be reduced to about 20% of the upland value. As a result, erosion may induce unaccounted sinks or sources of CO2, depending on the fate of eroded carbon and its protection from decomposition. For erosion rates typical of the United States, the sink terms may be large enough (1 Gt yr-1, back-of-the-envelope) to warrant a careful accounting of site management, cropping, and fertilization histories, as well as burial rates, for a more meaningful global assessment.

  2. Investigating the Influence of Clay Mineralogy on Stream Bank Erodibility

    NASA Astrophysics Data System (ADS)

    Ambers, R. K.; Stine, M. B.

    2005-12-01

    Soil scientists concerned with erosion of agricultural fields and geotechnical engineers concerned with the mechanical behavior of soils under different conditions have both examined the role of clay mineralogy in controlling soil/sediment properties. Fluvial geomorphologists studying stream channel erosion and stability have focused more on the effects of particle-size distribution, vegetation and rooting. The clay mineralogy of bed and bank sediment has the potential to influence cohesiveness and erodibility, however. The goal of this study is to determine the influence of clay mineralogy on the erodibility of natural stream bank sediment, utilizing techniques drawn from pedology and soil mechanics. Bank samples were collected from eleven sites in small watersheds in central and western Virginia. To obtain sediment containing a range of different clay minerals, watersheds with different types of bedrock were chosen for sampling. Rock types included mafic to felsic metamorphic and igneous rocks, shale, sandstone, and limestone. Where stream bank materials were clearly stratified, different layers were sampled separately. X-ray diffraction of the clay-fraction of the sediment indicates the presence of kaolinite, illite, vermiculite, and mixed-layer clay minerals in various abundances in the different samples. Clay content is 9-46%, as determined by the hydrometer method, and textures range from silty clay and silt loam to clay loam and sandy loam. Organic mater contents range from 1-5% by the loss-on-ignition method. Bulk density of intact sediment samples averages 1.5 g/cc. Liquid limits range from 23-41 with one sample having a value of 65; plasticity indices range from 15-22. While these tests predict that the samples would show a range of mechanical behaviors, the channel morphology at the sampling sites was not strikingly different, all having steep cut banks eroded primarily by scour with no evidence of mass movement and most having a width/depth ratio around

  3. The potential role of polyamines in gill epithelial remodeling during extreme hypoosmotic challenges in the Gulf killifish, Fundulus grandis.

    PubMed

    Guan, Ying; Zhang, Guo-Xia; Zhang, Shujun; Domangue, Beau; Galvez, Fernando

    2016-01-01

    Polyamines are a family of low molecular weight organic cations produced in part by the coordinated actions of arginase II (Arg II) and ornithine decarboxylase (Odc). Although gill polyamine homeostasis is affected by acute transfer to fresh water, little is known of its function in fish osmoregulation. The current study investigated the role of polyamines in the compensatory response of hypoosmotic challenge in the euryhaline fish, Fundulus grandis. Adult F. grandis were acclimated to 5 ppt water, transferred abruptly to 5, 2, 1, 0.5 and 0.1 ppt water, and assessed for osmoregulatory function, gill morphology, and polyamine homeostasis. The plasma osmolality, Na(+) concentration, and Cl(-) concentration were only significantly reduced during exposure to salinities at or below 0.5 ppt, although these effects were transient except in the 0.1 ppt treatment. The phenotype of mitochondrion-rich cells (MRCs) shifted from a seawater-type to a freshwater-type only at salinities that also produced a plasma osmotic disturbance. Hypoosmotic exposure increased the concentrations of putrescine, spermidine, and spermine in the gill over the entire 7 day period. Exposure to 0.1 ppt water also transiently increased gill caspase-3 activity and gill mRNA levels of the immediate-early response genes, c-fos and c-myc, thus tightly associating polyamines with gill remodeling during freshwater acclimation. Furthermore, arginase II and ornithine decarboxylase mRNA levels were most highly expressed in MRCs, and these levels were further increased only in the 0.1 ppt treatment. Reduction of gill polyamine levels following administration of the Odc inhibitor, alpha-dl-difluoromethylornithine (DFMO), inhibited gill caspase-3 activity, but surprisingly reduced the magnitude of the plasma osmotic imbalance elicited by exposure to 0.1 ppt water. We used isolated opercular epithelia mounted on Ussing chambers to assess the influence of polyamines on the attenuating response of hypotonic shock

  4. Carbonic anhydrase, a respiratory enzyme in the gills of the shore crab Carcinus maenas

    NASA Astrophysics Data System (ADS)

    Böttcher, K.; Siebers, D.; Sender, S.

    1995-03-01

    This paper summarizes investigations on the enzyme carbonic anhydrase (CA) in the gills of the osmoregulating shore crab Carcinus maenas. Carbonic anhydrase, an enzyme catalyzing the reversible hydration of CO2 to HCO3 - and H+, is localized with highest activities in the posterior salt-transporting gills of the shore crab- and here CA activity is strongly dependent on salinity. Contrary to the earlier hypothesis established for the blue crab Callinectes sapidus that cytoplasmic branchial CA provides the counter ions HCO3 - and H+ for apical exchange against Na+ and Cl-, the involvement of CA in NaCl uptake mechanisms can be excluded in Carcinus. Differential and density gradient centrifugations indicate that branchial CA is a predominantly membrane-associated protein. Branchial CA was greatly inhibited by the sulfonamide acetazolamide (AZ) Ki=2.4·10-8 mol/l). Using the preparation of the isolated perfused gill, application of 10-4 mol/l AZ resulted in an 80% decrease of CO2/HCO3 - excretion. Thus we conclude that CA is localized in plasma membranes, maintaining the CO2 gradient by accelerating adjustment of the pH-dependent CO2/HCO3 - equilibrium.

  5. Mitochondrial ATPase in the gills of the shore crab Carcinus maenas

    NASA Astrophysics Data System (ADS)

    Siebers, D.; Hentschel, J.; Böttcher, K.; Lucu, C.

    1992-12-01

    Posterior gills (No. 7 and 8) of shore crabs Carcinus maenas were homogenized and fractionated by means of differential and density gradient centrifugation. Employment of marker enzymes Na-K-ATPase and carbonic anhydrase for plasma membranes and cytochrome oxidase for mitochondria showed that these structural elements were separated. Ultramicroscopic investigations of combined fractions confirmed the presence of the respective mitochondrial and vesicular plasma membrane structures. An ATPase which did not depend on the presence of sodium (20 mM) ions in the incubation medium but on the presence of potassium (20 mM) ions only was found in the mitochondrial fractions. The mitochondrial ATPase was tightly bound to cellular particulates and activated approximately threefold by bicarbonate (20 mM) ions. The activity of this ATPase was nearly completely inhibited by oligomycin (1 μg ml-1) and greatly inhibited by low levels (5 mM) of thiocyanate and calcium ions, the Ki for Ca2+ being ca 4 mM. The results obtained confirm literature data on high mitochondrial densities in crab gills and allow the assumption of significant rates of energy metabolism in these organs. Considering its properties the mitochondrial ATPase is clearly distinct from crab gill Na-K-ATPase and can be measured specifically in samples containing Na-K-ATPase. Mitochondrial ATPase is therefore considered a suitable and reliable marker enzyme for mitochondria.

  6. Impact of long-term moderate hypercapnia and elevated temperature on the energy budget of isolated gills of Atlantic cod (Gadus morhua).

    PubMed

    Kreiss, Cornelia M; Michael, Katharina; Bock, Christian; Lucassen, Magnus; Pörtner, Hans-O

    2015-04-01

    Effects of severe hypercapnia have been extensively studied in marine fishes, while knowledge on the impacts of moderately elevated CO2 levels and their combination with warming is scarce. Here we investigate ion regulation mechanisms and energy budget in gills from Atlantic cod acclimated long-term to elevated PCO2 levels (2500 μatm) and temperature (18°C). Isolated perfused gill preparations were established to determine gill thermal plasticity during acute exposures (10-22°C) and in vivo costs of Na(+)/K(+)-ATPase activity, protein and RNA synthesis. Maximum enzyme capacities of F1Fo-ATPase, H(+)-ATPase and Na(+)/K(+)-ATPase were measured in vitro in crude gill homogenates. After whole animal acclimation to elevated PCO2 and/or warming, branchial oxygen consumption responded more strongly to acute temperature change. The fractions of gill respiration allocated to protein and RNA synthesis remained unchanged. In gills of fish CO2-exposed at both temperatures, energy turnover associated with Na(+)/K(+)-ATPase activity was reduced by 30% below rates of control fish. This contrasted in vitro capacities of Na(+)/K(+)-ATPase, which remained unchanged under elevated CO2 at 10°C, and earlier studies which had found a strong upregulation under severe hypercapnia. F1Fo-ATPase capacities increased in hypercapnic gills at both temperatures, whereas Na(+)/K(+)ATPase and H(+)-ATPase capacities only increased in response to elevated CO2 and warming indicating the absence of thermal compensation under CO2. We conclude that in vivo ion regulatory energy demand is lowered under moderately elevated CO2 levels despite the stronger thermal response of total gill respiration and the upregulation of F1Fo-ATPase. This effect is maintained at elevated temperature. PMID:25535111

  7. TIE of a PAH-contaminated sediment using reproductive responses and EROD induction in rainbow trout

    SciTech Connect

    Brumley, C.M.; Kraak, G. van der; Munkittrick, K.R.

    1995-12-31

    PAH-contaminated sediments have been shown to cause a range of effects in fish. However, identifying the effective compounds can be time consuming and expensive. A toxicity identification evaluation (TIE) involves the analysis of mixtures by initially separating the mixture into toxic and non-toxic constituents. In this study, sediment was collected from Hamilton Harbor, Lake Ontario, and either extracted wet using methanol (MeOH) and dichloromethane (DCM), or freeze-dried and soxhlet extracted with MeOH and DCM. DCM extracts were solvent exchanged with dimethylsulfoxide (DMSO). Juvenile rainbow trout (Oncorhynchus mykiss) were exposed through the water to wet, freeze-dried, or extracted sediment, or to the MeOH or DMSO extracts for 4 days. Fish were analyzed for hepatic EROD activity, and plasma DMSO extracts, but was unaffected in fish exposed to extracted sediment. Estradiol levels were increased in fish exposed to the wet sediment, but not in fish exposed to the freeze-dried or extracted sediment, nor either of the solvent extracts. The response of testosterone to wet, freeze-dried and extracted sediment was inconsistent. Results indicate that both of the extraction methods efficiently removed from the sediment the compounds responsible for the effects on EROD activity and estradiol levels. However, neither method retained in the solvent extracts the compounds causing the increases in estradiol levels. Work continues to refine the freeze-drying and extraction methods; extracts will then be further fractionated using HPLC to identify the compounds of concern.

  8. Effect of erodent particles on the erosion of metal specimens

    NASA Astrophysics Data System (ADS)

    Razzaque, M. Mahbubur; Alam, M. Khorshed; Khan, M. Ishak

    2016-07-01

    This paper presents the experimental results of the measurement of erosion rate of carbon steel specimens in sand water slurry system in a slurry pot tester. Sylhet sand has been sieved to get three sizes of erodent particles; namely, less than 250 micron, 250 to 590 micron and 590 to 1190 micron. Experiments are done with three sand concentrations (10%, 15% and 20%). The rate of erosion of the carbon steel specimens is measured as the loss of weight per unit surface area per unit time under the dynamic action of solid particles. The eroded surfaces of the specimens are examined using Scanning Electron Microscopy (SEM) to visualize the impact of the slurry of various conditions. It is seen that irrespective of the particle size the rate of erosion increases with the increase of slurry concentration. This increment of erosion rate at high concentration is high for large particles. High erosion rate is observed in case of large sand particles. In case of small and fine particles erosion rate is small because of low impact energy as well as the wastage of energy to overcome the hindrance of the finer particles before striking on the specimen surface.

  9. Fates of eroded soil organic carbon: Mississippi Basin case study

    USGS Publications Warehouse

    Smith, S.V.; Sleezer, R.O.; Renwick, W.H.; Buddemeier, R.W.

    2005-01-01

    We have developed a mass balance analysis of organic carbon (OC) across the five major river subsystems of the Mississippi (MS) Basin (an area of 3.2 ?? 106 km2). This largely agricultural landscape undergoes a bulk soil erosion rate of ???480 t??km -2??yr-1 (???1500 ?? 106 t/yr, across the MS Basin), and a soil organic carbon (SOC) erosion rate of ???7 t??km-2??yr-1 (???22 ?? 106 t/yr). Erosion translocates upland SOC to alluvial deposits, water impoundments, and the ocean. Soil erosion is generally considered to be a net source of CO2 release to the atmosphere in global budgets. However, our results indicate that SOC erosion and relocation of soil apparently can reduce the net SOC oxidation rate of the original upland SOC while promoting net replacement of eroded SOC in upland soils that were eroded. Soil erosion at the MS Basin scale is, therefore, a net CO2 sink rather than a source. ?? 2005 by the Ecological Society of America.

  10. Evaluation of histopathological alterations in the gills of Vardar chub (Squalius vardarensis Karaman) as an indicator of river pollution.

    PubMed

    Barišić, Josip; Dragun, Zrinka; Ramani, Sheriban; Filipović Marijić, Vlatka; Krasnići, Nesrete; Čož-Rakovac, Rozelindra; Kostov, Vasil; Rebok, Katerina; Jordanova, Maja

    2015-08-01

    Quantification of histopathological alterations in the gills of Vardar chub (Squalius vardarensis Karaman) was performed in 2012 in rivers of north-eastern Macedonia, with the aim to examine the effects of water quality in the rivers (Zletovska and Kriva River-impacted by active Pb/Zn mines; Bregalnica River-contaminated by agricultural waste). The biological alterations in chub were classified as: circulatory disturbances, regressive and progressive changes, but their severity differed. Altogether the mildest changes were observed in the gills of chub from the Bregalnica River, a less polluted river, whereas mining impacted rivers were characterized by more severe alterations. In the gills of chub from the Zletovska River, which is highly contaminated with numerous metals, sulphates and chlorides, the highest lesion indices were found for the regressive changes of both epithelium and supporting tissue, with typical lesions referring to atrophy, thinning and lifting of epithelial cells, necrosis of epithelium and chloride cells, as well as deformations of lamellar cartilaginous base. Gill damages of chub from the Kriva River were overall milder compared to the Zletovska River, in accordance with pollution status. In the gills of chub from that river, progressive changes were more pronounced, specifically severe hyperplasia of mucous cells and epithelium in the interlammellar space, leading to fusion of lamellae, as well as hypertrophy of chloride cells. The comparison between seasons indicated higher intensity of progressive changes in all three rivers in autumn, when water level was very low, and consequently, water contamination was more pronounced due to concentration effect. The pattern and severity of histopathological alterations in the chub gills reflected differences in contamination levels and type of contaminants in different rivers and sampling periods, and thus have been proven as a valuable indicator of water quality. PMID:25938696

  11. Temperature effects on hatching and viability of Juvenile Gill Lice, Salmincola californiensis.

    PubMed

    Vigil, E M; Christianson, K R; Lepak, J M; Williams, P J

    2016-07-01

    Salmonids of the genus Oncorhynchus, distributed throughout the Pacific Rim, can be infected by the gill lice species Salmincola californiensis (Dana, 1852), which makes them one of the most broadly distributed gill lice species. Despite their broad distribution and valuable obligate salmonid hosts, relatively little is known about S. californiensis. We evaluated effects of temperature on timing of S. californiensis hatching and survival of copepodids, and provide information on brood size and variability. Our results suggest that temperature was a primary driver of timing of S. californiensis hatching and post-hatching survival. Prior to this study, the free-swimming stage of S. californiensis was reported to survive approximately 2 days without a suitable host. We observed active copepodids 13 days after hatch with some individuals from most (>90%) viable egg sacs at all temperature treatments surviving ≥5 days. Our findings indicate that warmer temperatures could increase development rates of gill lice at certain life stages, potentially increasing fecundity. This information coupled with predictions that warmer water temperatures could intensify crowding of coldwater fishes, stress, and parasite transmission suggests that climate change could exacerbate negative effects of S. californiensis on ecologically and economically important salmonids. PMID:26538200

  12. The nephridial hypothesis of the gill slit origin.

    PubMed

    Ezhova, Olga V; Malakhov, Vladimir V

    2015-12-01

    Metameric gill slits are mysterious structures, unique for Chordata and Hemichordata, and also, perhaps, for the extinct Cambrian Calcichordata. There is a discussed hypothesis of the gill slits origin from the metameric nephridia. According to the hypothesis, the hypothetical metameric deuterostome ancestor had in each segment a pair of coelomoducts and a pair of intestinal pockets. In the anterior segments, the coelomoducts have fused with the intestinal pockets. As a result, each nephridium opened both into the gut and into the environment. Then the dissepiments and funnels reduced in all segments except the collar one. Thus, in recent enteropneusts, only the first pair of gill slits keeps the ancestral arrangement communicating at the same time with the gut, with the environment, and with the coelom of the preceding (collar) segment. In the anterior part of the branchio-genital trunk region of enteropneusts, the metameric intestinal pockets remained, as well as the metameric coelomoducts functioning as the ducts of the metameric gonads, i.e., as the gonoducts. The consequence of the hypothesis is that the metameric gill pores originate from the metameric excreting pores, and the metameric branchial sacs originate from the metameric endodermal pockets of the gut fused with the coelomoducts. The metameric gill slits by themselves correspond with metameric openings connecting the gut with metameric intestinal pockets. J. Exp. Zool. (Mol. Dev. Evol.) 324B: 647-652, 2015. © 2015 Wiley Periodicals, Inc. PMID:26227807

  13. Damage to the gills and integument of Litoria fallax larvae (Amphibia: Anura) associated with ionoregulatory disturbance at low pH.

    PubMed

    Meyer, Edward A; Cramp, Rebecca L; Franklin, Craig E

    2010-02-01

    In fish, exposure to waters of low pH causes significant damage to the gill resulting in fatal iono- and osmoregulatory disturbance. In amphibians, exposure to acid waters also disrupts ionic homeostasis, however the extent and nature of injuries to amphibian larvae from acid exposure are poorly understood. Changes in gross morphology and ultrastructure of the gills and integument were examined, together with measures of Na(+) efflux/uptake, in larval Litoria fallax (Amphibia: Anura) following acute acid exposure. Examination of tissues revealed significant changes in morphology and ultrastructure of both gills and the integument following acutely lethal exposure to low pH water. Changes to the gills of acid-exposed L. fallax larvae included lifting of the branchial epithelium and opening of tight junctions between pavement cells (with a consequent reduction in tight junction length). Damage to epithelial cell-cell tight junctions was also apparent at the integument along with widespread oncosis and localised epithelial necrosis. Mucous secretory activity at the gills and body surface was largely unaffected by acid exposure, with little or no difference in density, cross-sectional area and number of epithelial mucous secretory vesicles in acid-exposed and control larvae. Changes in morphology and ultrastructure at low pH were accompanied by significant Na(+) loss (up to 50% of the total body Na(+) content) attributable in large part to increased paracellular ionic efflux across the gills as well as increased transcellular and paracellular efflux of ions across the integument. PMID:19879955

  14. Experimental simulation of gravity currents in erodible bed

    NASA Astrophysics Data System (ADS)

    Bateman, A.; La Roca, M.; Medina, V.

    2009-04-01

    Gravity currents are commonly met in nature, when a flow of denser fluid moves into a less dense one. A typical example of a gravity current is given by the sea water which flows into the bottom of a river during the summer, in correspondence of the estuary, when the river's discharge attains low values. In this case, dangerous consequences can occur, because of the polluting of the aquifer caused by the salty water. Density currents also occurs in lakes and reservoirs, because of a change in temperature or because a flood, both can produce some environmental impacts that are of interest to the local water Agency of the different countries. Of particular relevance is also the interaction of the gravity current with the movement of the sediments from the bottom of the bed. The international state of the art is particularly concerned with experimental and numerical investigation on gravity currents on fixed and porous bed [1-2-3], while, to the authors' knowledge, the interaction of a gravity current with an erodible bed is still an open field of investigation. In this paper experiments concerning with the propagation of a gravity current over fixed and erodible bed are presented. The experiments, conducted at the laboratory of Hydraulics of the Universitat Politecnica de Catalunya (actually in the Prof. Bateman's blue room), were concerned with a transparent tank 2 m long, 0.2 m wide and 0.3 m deep, partly filled with salty water and partly with fresh water, up to a depth of 0.28 m. The salty water, whose density was in the range 1050erodible bed. In this latter case a homogeneous sand (d50=0.3 mm) was used. The results, concerned with the visualisation of the flow and the measurement of the wave front velocity, were obtained. Also the size and the frequency of the new vortices

  15. Oxidative stress responses in blood and gills of Carassius auratus exposed to the mancozeb-containing carbamate fungicide Tattoo.

    PubMed

    Kubrak, Olga I; Atamaniuk, Tetiana M; Husak, Viktor V; Drohomyretska, Ivanna Z; Storey, Janet M; Storey, Kenneth B; Lushchak, Volodymyr I

    2012-11-01

    Intensive use of pesticides, particularly dithiocarbamates, in agriculture often leads to contamination of freshwater ecosystems. To our knowledge, the mechanisms of toxicity to fish by the carbamate fungicide Tattoo that contains mancozeb [ethylenebis(dithiocarbamate)] have not been studied. The present study aimed to evaluate the effects of Tattoo on goldfish gills and blood, tissues that would have close early contact with the pollutant. Exposure of goldfish Carassius auratus to 3, 5 or 10mgL(-1) of Tattoo for 96h resulted in moderate lymphopenia (by 8 percent) with a concomitant increase in both stab (by 66-88 percent) and segmented (by 166 percent) neutrophils. An increase in the content of protein carbonyl groups in blood (by 137-184 percent) together with decreased levels of protein thiols (by 23 percent) and an enhancement of lipid peroxide concentrations (by 29 percent) in gills after exposure to 10mgL(-1) of Tattoo demonstrated the induction of mild oxidative stress in response to Tattoo exposure. At the same time, the activities of selected antioxidant enzymes were enhanced in gills: superoxide dismutase by 18-25 percent and catalase by 27 percent. A 34 percent increment in low molecular mass thiol concentrations (mainly represented by glutathione) also occurred in gills and could be related to increased activity (by 13-30 percent) of glucose-6-phosphate dehydrogenase. The results indicate that Tattoo exposure perturbs free radical processes, i.e. induces mild oxidative stress and enhances the activity of certain antioxidant and associated enzymes in goldfish gills. It is clear that goldfish respond to the presence of waterborne pesticide by adjusting antioxidant defenses through upregulation of activities of antioxidant and associated enzymes. PMID:22963715

  16. Analysis of eroded bovine teeth through laser speckle imaging

    NASA Astrophysics Data System (ADS)

    Koshoji, Nelson H.; Bussadori, Sandra K.; Bortoletto, Carolina C.; Oliveira, Marcelo T.; Prates, Renato A.; Deana, Alessandro M.

    2015-02-01

    Dental erosion is a non-carious lesion that causes progressive tooth wear of structure through chemical processes that do not involve bacterial action. Its origin is related to eating habits or systemic diseases involving tooth contact with substances that pose a very low pH. This work demonstrates a new methodology to quantify the erosion by coherent light scattering of tooth surface. This technique shows a correlation between acid etch duration and laser speckle contrast map (LASCA). The experimental groups presented a relative contrast between eroded and sound tissue of 17.8(45)%, 23.4 (68)% 39.2 (40)% and 44.3 (30)%, for 10 min, 20 min, 30 min and 40 min of acid etching, respectively.

  17. Eroding market stability by proliferation of financial instruments

    NASA Astrophysics Data System (ADS)

    Caccioli, F.; Marsili, M.; Vivo, P.

    2009-10-01

    We contrast Arbitrage Pricing Theory (APT), the theoretical basis for the development of financial instruments, with a dynamical picture of an interacting market, in a simple setting. The proliferation of financial instruments apparently provides more means for risk diversification, making the market more efficient and complete. In the simple market of interacting traders discussed here, the proliferation of financial instruments erodes systemic stability and it drives the market to a critical state characterized by large susceptibility, strong fluctuations and enhanced correlations among risks. This suggests that the hypothesis of APT may not be compatible with a stable market dynamics. In this perspective, market stability acquires the properties of a common good, which suggests that appropriate measures should be introduced in derivative markets, to preserve stability. in here

  18. Effects of erodant particle shape and various heat treatments on erosion resistance of plain carbon steel

    NASA Technical Reports Server (NTRS)

    Salik, J.; Buckley, D. H.

    1981-01-01

    Erosion tests were conducted on 1045 steel samples which had been subjected to different heat treatments. The weight of material removed upon erosion with glass beads and crushed glass was measured. The data show that there is no correlation between hardness and erosion resistance. The erosion rate was strongly dependent on the shape of erodant particles, being an order of magnitude higher for erosion with crushed glass than with glass beads. Heat treatment had a profound effect on the erosion resistance when the erodant particles were glass beads but little or no effect when the particles were crushed glass. It is thus concluded that different mechanisms of material removal are involved with these two erodants. This conclusion is supported by the surface morphology of annealed 1045 steel samples which had been eroded by these two types of erodant particles. SEM micrographs of the eroded surfaces show that for erosion with glass beads it is deformation induced fracture of surface layers.

  19. Development of oxygen sensing in the gills of zebrafish.

    PubMed

    Jonz, Michael G; Nurse, Colin A

    2005-04-01

    Previous studies have described the morphology, innervation and O(2)-chemoreceptive properties of neuroepithelial cells (NECs) of the zebrafish gill filaments. The present work describes the ontogenesis of these cells, and the formation of functional O(2)-sensing pathways in developing zebrafish. Confocal immunofluorescence was performed on whole-mount gill preparations using antibodies against serotonin (5-HT) and a zebrafish-derived neuronal marker (zn-12) to identify the appearance and innervation of gill NECs during larval stages. NECs were first expressed in gill filament primordia of larvae at 5 days postfertilization (d.p.f.) and were fully innervated by 7 d.p.f. In vivo ventilation frequency analysis revealed that a behavioural response to hypoxia (11.2+/-2.8 min(-1)) developed in embryos as early as 2 d.p.f., and a significant increase (P<0.05) in the ventilatory response to hypoxia (200.8+/-23.0 min(-1)) coincided with innervation of NECs of the filaments. In addition, exogenous application of quinidine, a blocker of O(2)-sensitive background K(+) channels in NECs, induced hyperventilation in adults in a dose-dependent manner and revealed the development of a quinidine-sensitive ventilatory response in 7 d.p.f. larvae. This study shows that NEC innervation in the gill filaments may account for the development of a functional O(2)-sensing pathway and the hyperventilatory response to hypoxia in zebrafish larvae. At earlier stages, however, O(2)-sensing must occur through another pathway. The possibility that a new type of 5-HT-positive NEC of the gill arches may account for this earlier hypoxic response is discussed. PMID:15802677

  20. In vitro acute cytotoxicity of abamectin to the Gill Cell Line of Flounder Paralichthy olivaceus

    NASA Astrophysics Data System (ADS)

    Xu, Yuyan; Guo, Huarong; Xiao, Qin; Su, Feng; Yin, Licheng

    2007-10-01

    The cytotoxicity of abamectin to the Gill Cell Line of Flounder (FG cell line) was examined in this study. It was found that the exposure of FG cells to abamectin caused the decreases of both cell growth rate and antioxidant enzyme activities, and the increase of intracellular O2 - content. It was proposed that the reduction of antioxidant enzyme activities in FG cells caused the accumulation of O2 - content in FG cells, leading to the change of cell morphology and even the death of cells. The results showed that FG cell line is suitable for the evaluation of the acute toxicity of abamectin.

  1. Dietary salt loading and ion-poor water exposure provide insight into the molecular physiology of the rainbow trout gill epithelium tight junction complex.

    PubMed

    Kolosov, Dennis; Kelly, Scott P

    2016-08-01

    This study utilized dietary salt loading and ion-poor water (IPW) exposure of rainbow trout (Oncorhynchus mykiss) to further understand the role of fish gill epithelium tight junction (TJ) physiology in salt and water balance. Gill morphology, biochemistry and molecular physiology were examined, with an emphasis on genes encoding TJ proteins. Fish were either fed a control or salt-enriched diet (~10 % NaCl) for 4 weeks prior to IPW exposure for 24 h. Serum [Na(+)], [Cl(-)] and muscle moisture content were unaltered by salt feeding, but changed in response to IPW irrespective of diet. Dietary salt loading altered the morphology (reduced Na(+)-K(+)-ATPase-immunoreactive cell numbers and surface exposure of mitochondrion-rich cells), biochemistry (decreased vacuolar-type H(+)-ATPase activity) and molecular physiology (decreased nkaα1a and cftrII mRNA abundance) of the gill in a manner indicative of reduced active ion uptake activity. But in control fish and not salt-fed fish, gill mRNA abundance of nkaα1c increased and nbc decreased after IPW exposure. Genes encoding TJ proteins were typically either responsive to salt feeding or IPW, but select genes responded to combined experimental treatment (e.g. IPW responsive but only if fish were salt-fed). Therefore, using salt feeding and IPW exposure, new insights into what factors influence gill TJ proteins and the role that specific TJ proteins might play in regulating the barrier properties of the gill epithelium have been acquired. In particular, evidence suggests that TJ proteins in the gill epithelium, or the regulatory networks that control them, respond independently to external or internal stimuli. PMID:27083431

  2. Expression studies on NA+/K(+)-ATPase in gills of Penaeus monodon (Fabricius) acclimated to different salinities.

    PubMed

    Chaudhari, Aparna; Gireesh-Babu, P; Tripathi, Gayatri; Sabnis, Supriya; Dhamotharan, K; Vardarajan, Remya; Kumari, Kavita; Dasgupta, Subrata; Rajendran, K V

    2015-05-01

    The decapod crustacean Penaeus monodon survives large fluctuations in salinity through osmoregulation in which Na+/K(+)-ATPase (NKA) activity in the gills plays a central role. Adult P. monodon specimens were gradually acclimatized to 5, 25 and 35 per thousand salinities and maintained for 20 days to observe long-term alterations in NKA expression. Specific NKA activity assayed in gill tissues was found to be 3 folds higher at 5 per thousand compared to 25 per thousand (isosmotic salinity) and 0.48 folds lower at 35 per thousand. The enzyme was immunolocalized in gills using mouse α-5 monoclonal antibody that cross reacts with P. monodon NKA α-subunit. At 5 per thousand the immunopositive cells were distributed on lamellar tips and basal lamellar epithelium of the secondary gill filaments and their number was visibly higher. At both 25 per thousand and 35 per thousand NKA positive cells were observed in the inter-lamellar region but the expression was more pronounced at 25 per thousand. Gill architecture was normal at all salinities. However, the 1.5 fold increase in NKA α-subunit mRNA at 5 per thousand measured by quantitative RT-PCR (qRT-PCR) using EF1α as reference gene was not statistically significant. The study confirms the osmoregulating ability of P. monodon like other crustaceans at lower salinities. It is likely that significant increase in NKA transcript level happens at an earlier time point. At higher salinities all three methods record only marginal or no change from isosmotic controls confirming the hypothesis that the animal largely osmoconforms in hyperosmotic environment. PMID:26040024

  3. Time-course changes in the expression of Na+, K+-ATPase in gills and pyloric caeca of brown trout (Salmo trutta) during acclimation to seawater.

    PubMed

    Seidelin, M; Madsen, S S; Blenstrup, H; Tipsmark, C K

    2000-01-01

    Changes in protein and mRNA expression of Na(+),K(+)-ATPase in gills and pyloric caeca of brown trout were investigated on a detailed time course after transfer from freshwater to 25 ppt seawater (SW). A transient deflection in plasma osmolality and muscle water content lasting from 4 h until day 3 was followed by restoration of hydromineral balance from day 5 onward. Gills and pyloric caeca responded to SW transfer by increasing Na(+),K(+)-ATPase activity from days 5 and 3, respectively, onward. In both tissues, this response was preceded by an increase in alpha-subunit Na(+), K(+)-ATPase mRNA as early as 12 h posttransfer. The similarity of the response in these two organs suggests that they both play significant physiological roles in restoring hydromineral balance after abrupt increase in salinity. Further, SW transfer induced a slight, though significant, increase in primary gill filament Na(+), K(+)-ATPase immunoreactive (NKIR) cell abundance. This was paralleled by a marked (50%) decrease in secondary lamellar NKIR cell abundance after less than 1 d in SW. Thus, SW acclimation in brown trout is characterised by a lasting decrease in overall NKIR cell abundance in the gill. We propose that SW transfer stimulates Na(+),K(+)-ATPase enzymatic activity within individual chloride cells long before (<1 d) it becomes apparent in measurements of whole-gill homogenate enzymatic activity. This is supported by the early stabilisation (12 h) of hydromineral balance. PMID:11009398

  4. Context of Carbonate Rocks in Heavily Eroded Martian Terrain

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The color coding on this composite image of an area about 20 kilometers (12 miles) wide on Mars is based on infrared spectral information interpreted as evidence of various minerals present. Carbonate, which is indicative of a wet and non-acidic history, occurs in very small patches of exposed rock appearing green in this color representation, such as near the lower right corner.

    The scene is heavily eroded terrain to the west of a small canyon in the Nili Fossae region of Mars. It was one of the first areas where researchers on the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) science team detected carbonate in Mars rocks. The spectral information comes from infrared imaging by CRISM, one of six science instruments on NASA's Mars Reconnaissance Orbiter. That coloring is overlaid on a grayscale image from the same orbiter's Context Camera.

    The uppermost capping rock unit (purple) is underlain successively by banded olivine-bearing rocks (yellow) and rocks bearing iron-magnesium smectite clay (blue). Where the olivine is a greenish hue, it has been partially altered by interaction with water. The carbonate and olivine occupy the same level in the stratigraphy, and it is thought that the carbonate formed by aqueous alteration of olivine. The channel running from upper left to lower right through the image and eroding into the layers of bedrock testifies to the past presence of water in this region. That some of the channels are closely associated with carbonate (lower right) indicates that waters interacting with the carbonate were neutral to alkaline because acidic waters would have dissolved the carbonate.

    Information for the color coding came from CRISM images catalogued as FRT0000B438, FRT0000A4FC, and FRT00003E12. This composite was made using 2.38-micrometer-wavelenghth data as red, 1.80 micrometer as green and 1.15 micrometer as blue.

    The base black-and-white image, acquired at a resolution of 5 meters (16 feet) per

  5. Modeling sediment delivery from a highly erodible mountain catchment

    NASA Astrophysics Data System (ADS)

    Le Bouteiller, C.; Asif, N. M.; Recking, A.; Liebault, F.

    2015-12-01

    Draix observatory is located in the French Alps on a highly erodible substrate of shale. Most of the observatory is in a badland area characterized by steep gullies and high erosion rates (up to 1cm/year). Within the observatory, the study focuses on the Moulin, which is an 8ha catchment located at an elevation of 850-925m, with 54% of badland area. Available data includes DEM, meteorological data, high-frequency records of discharge and suspended sediment concentration during the floods, cumulative values of bedload transport for each flood, high-frequency records of bedload transport for a few events from a Birkbeck sampler. Modeling sediment delivery in such a catchment is challenging because 1) most available models have been designed for low-relief regions and do not account for steep slope processes such as debris flow and landslides; 2) hydrology (especially flashfloods) in mountainous regions is not well understood; 3) soil properties are very heterogeneous ; 4) multiple time scales are involved: seasonal sediment production on the slopes, storage in the bed and exportation requires to work on yearly times scales, while summer floods and most sediment delivery events occur over a few minutes only. We evaluate the ability of the SHETRAN model to reproduce sediment delivery patterns from the catchment. First, we calibrate the hydrological model using one year of meteorological and hydrological data. We then apply the sediment transport module over several flood events, using in-situ measurements of bed and slope grain-size distributions. Finally we investigate how sediment available on the slopes moves through the catchment over a year. Event-scale volumes of sediment simulated by the model are comparable to observed values within an order of 2. Sediment delivery rates are very sensitive to the slope grain-size distribution. Depending on sediment availability on the slopes and on soil erodibility, the catchment is running either in a supply-limited or

  6. Poly(vinyl alcohol) Physical Hydrogels: Matrix-Mediated Drug Delivery Using Spontaneously Eroding Substrate.

    PubMed

    Jensen, Bettina E B; Dávila, Izaskun; Zelikin, Alexander N

    2016-07-01

    Poly(vinyl alcohol) hydrogels have a long and successful history of applications in biomedicine. Historically, these matrices were developed to be nondegradable-limiting their utility to applications as permanent implants. For tissue engineering and drug delivery, herein we develop spontaneously eroding physical hydrogels based on PVA. We characterize in detail a mild, noncryogenic method of producing PVA physical hydrogels using poly(ethylene glycol) as a gelating agent, and investigate PVA molar mass as a means to define the kinetics of erosion of these biomaterials. PVA hydrogels are characterized for associated inflammatory response in adhering macrophages, antiproliferative effects mediated through delivery of cytotoxic drugs to myoblasts, and pro-proliferative activity achieved via presentation of conjugated growth factors to endothelial cells. Together, these data present a multiangle characterization of these novel multifunctional matrices for applications in tissue engineering and drug delivery mediated by implantable biomaterials. PMID:26958864

  7. Psychological Aspects of Gilles De La Tourette Syndrome.

    ERIC Educational Resources Information Center

    Grossman, Hildreth Youkilis; And Others

    1986-01-01

    Evaluated the psychopathological features that may underlie or accompany Gilles de la Tourette Syndrome. Univariate analyses indicated that Tourette subjects scored higher on the following scales of the Minnesota Multiphasic Personality Inventory: Schizophrenia, Depression, Psychopathic Deviate, Psychasthenia and Hypochondriasis. The results…

  8. Matter in Motion: The Educational Materialism of Gilles Deleuze

    ERIC Educational Resources Information Center

    Cole, David R.

    2012-01-01

    This paper critically examines the materialism that Gilles Deleuze espouses in his oeuvre to the benefit of educational theory. In "Difference and Repetition", he presented transcendental empiricism by underwriting Kant with realism (Deleuze, 1994). Later, in "Capitalism & Schizophrenia I & II" that were co-written with Felix Guattari (1984, 1988)…

  9. A case of Gilles de la Tourette's syndrome

    PubMed Central

    Prakash, Jyoti; Singh, Pragnya; Bhat, P. S.; Srivastava, K.; Gupta, Vikash

    2015-01-01

    Gilles de la Tourette's syndrome is an uncommon illness associated with repetitive un-voluntary abnormal movements and utterance. It is often associated with other psychiatric morbidities. Management requires awareness of this uncommon illness, keen observation, relevant evaluation, and combination of pharmacology and psychotherapy for an optimal outcome. This case is brought out here for florid presentation and nuances of management. PMID:27212827

  10. Identifying the Child with Gilles de la Tourette Syndrome.

    ERIC Educational Resources Information Center

    Anderson, Donna J.

    1993-01-01

    This article presents a brief introduction to Gilles de la Tourette Syndrome (a neuropsychiatric disorder characterized by motor and vocal tics and obsessive-compulsive behaviors). It describes the nature of the disorder, treatment, and service provision (evaluation and assessment and the Individual Education Plan). (DB)

  11. A case of Gilles de la Tourette's syndrome.

    PubMed

    Prakash, Jyoti; Singh, Pragnya; Bhat, P S; Srivastava, K; Gupta, Vikash

    2015-01-01

    Gilles de la Tourette's syndrome is an uncommon illness associated with repetitive un-voluntary abnormal movements and utterance. It is often associated with other psychiatric morbidities. Management requires awareness of this uncommon illness, keen observation, relevant evaluation, and combination of pharmacology and psychotherapy for an optimal outcome. This case is brought out here for florid presentation and nuances of management. PMID:27212827

  12. Simulated Conversations: The McGill Negotiation Simulator.

    ERIC Educational Resources Information Center

    Roston, John

    The ability to successfully conduct specialized conversations in stressful situations is an essential part of professional competence in a number of subject areas; however, there are few opportunities for students to practice the required skills in a realistic environment. The McGill Negotiation Simulator project was established to investigate the…

  13. Myxosporean hyperparasites of gill monogeneans are basal to the Multivalvulida

    PubMed Central

    2011-01-01

    Background Myxosporeans are known from aquatic annelids but parasitism of platyhelminths by myxosporeans has not been widely reported. Hyperparasitism of gill monogeneans by Myxidium giardi has been reported from the European eel and Myxidium-like hyperparasites have also been observed during studies of gill monogeneans from Malaysia and Japan. The present study aimed to collect new hyperparasite material from Malaysia for morphological and molecular descriptions. In addition, PCR screening of host fish was undertaken to determine whether they are also hosts for the myxosporean. Results Heavy myxosporean infections were observed in monogeneans from two out of 14 fish and were detected from a further five fish using specific PCRs and pooled monogenean DNA. Positive DNA isolates were sequenced and were from a single species of myxosporean. Myxospore morphology was consistent with Myxidium with histozoic development in the parenchymal tissues of the monogenean. Simultaneous infections in the fish could not be confirmed microscopically; however, identical myxosporean DNA could be amplified from kidney, spleen and intestinal tract tissues using the specific PCR. Small subunit (SSU) rDNA for the myxosporean was amplified and was found to be most similar (92%) to that of another hyperparasitic myxosporean from a gill monogenean from Japan and to numerous multivalvulidan myxosporeans from the genus Kudoa (89-91%). Phylogenetic analyses placed the hyperparasite sequence basally to clades containing Kudoa, Unicapsula and Sphaerospora. Conclusions The myxosporean infecting the gill monogenean, Diplectanocotyla gracilis, from the Indo-Pacific tarpon, Megalops cyprinoides, is described as a new species, Myxidium incomptavermi, based on a histozoic development in the monogenean host and its phylogenetic placement. We have demonstrated for the first time that a myxosporean hyperparasite of gill monogeneans is detectable in the fish host. However, myxospores could not be isolated

  14. Sculpting of an erodible body by flowing water.

    PubMed

    Ristroph, Leif; Moore, Matthew N J; Childress, Stephen; Shelley, Michael J; Zhang, Jun

    2012-11-27

    Erosion by flowing fluids carves striking landforms on Earth and also provides important clues to the past and present environments of other worlds. In these processes, solid boundaries both influence and are shaped by the surrounding fluid, but the emergence of morphology as a result of this interaction is not well understood. We study the coevolution of shape and flow in the context of erodible bodies molded from clay and immersed in a fast, unidirectional water flow. Although commonly viewed as a smoothing process, we find that erosion sculpts pointed and cornerlike features that persist as the solid shrinks. We explain these observations using flow visualization and a fluid mechanical model in which the surface shear stress dictates the rate of material removal. Experiments and simulations show that this interaction ultimately leads to self-similarly receding boundaries and a unique front surface characterized by nearly uniform shear stress. This tendency toward conformity of stress offers a principle for understanding erosion in more complex geometries and flows, such as those present in nature. PMID:23150552

  15. Eroding students' rural motivation: first do no harm?

    PubMed

    Hurst, Samia

    2014-01-01

    Migration of health professionals is one of the drivers of vast inequalities in access to healthcare, as medical graduates tend to move away from both poorer countries and rural areas. One of the central ethical problems raised in attempting to alleviate these inequalities is the tension between the healthcare needs of under-served patients and the rights of medical graduates to choose their place of work and specialty. If medical graduates had greater motivation to work in under-served rural areas, this tension would decrease accordingly. Medical schools have a duty to avoid eroding existing motivation for such training and practice. This duty has practical implications. Medical students' motivation regarding their choice of specialty changes during medical training, turning them away from choices such as primary care and rural practice towards more highly specialised, more hospital based specialties. Although students may be victims of a number of biases in the initial assessment, this is unlikely to be the whole story. Students' priorities are likely to change based on their admiration for specialist role models and the visibility of the financial and non-financial rewards attached to these specialties. Students may also have a false expectation upon admission that they will be proficient in rural medicine on graduation, and change their mind once they realise the limits of their skills in that area. Although the measures required to reverse this effect currently lack a solid evidence base, they are plausible and supported by the available data. PMID:25399015

  16. Modeling propellant combustion interacting with an eroding solid surface

    SciTech Connect

    Buckingham, A.C.

    1980-05-06

    A computatonal model of turbulent combustion flow acting on and influenced by an eroding wall surface is introduced. The combustion flow field is particle laden. Significant particulate mass loading occurs in the immediate neighborhood of the wall as a result of erosion products issuing from the deteriorating solid surface. In addition, cases are considered in which a substantial particle mass loading develops near the wall as a result of finely divided (sub micron diameter) particulates such as TiO/sub 2/ and talcum powder which are added to suppress erosion. In addition to statistical turbulent field particle flow interaction, the model includes multi-component molecular diffusion processes, and gas phase, gas/surface and or solid surface chemical reactions. Results indicate that despite the unsteady flow conditions, a limiting erosion rate is approached. This occurs as a result of the effective blowing off of the issing vapor phase products. The blowing reduces the gradients driving the incident combustion heat and mass transfer. An analogy is drawn to unsteady, ablative, heat transfer and thermal/material response in hypersonic aerodynamics. Surfaces investigated, at present, include bare steel and refractory metal coated steel walls.

  17. Value-Eroding Teacher Behaviors Scale: A Validity and Reliability Study

    ERIC Educational Resources Information Center

    Arseven, Zeynep; Kiliç, Abdurrahman; Sahin, Seyma

    2016-01-01

    In the present study, it is aimed to develop a valid and reliable scale for determining value-eroding behaviors of teachers, hence their values of judgment. The items of the "Value-eroding Teacher Behaviors Scale" were designed in the form of 5-point likert type rating scale. The exploratory factor analysis (EFA) was conducted to…

  18. Primary particle size distribution of eroded material affected by degree of aggregate slaking and seal development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Primary particle size distribution (PSD) of eroded sediments can be used to estimate potential nutrient losses from soil and pollution hazards to the environment. We studied eroded sediment PSDs from three saturated soils, packed in trays (20 x 40 x 4 cm), that had undergone either minimal aggregate...

  19. Pyrosequencing reveal distinct bacteria are carried in different wind eroded sediments from the same soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the microbial communities carried in wind-eroded sediments from various soil types and land management systems. A novel technique, named pyrosequencing, promises to expand our understanding of the vast microbial diversity of soils and eroded sediments as it can sequence between...

  20. Soil wind erodibility based on dry aggregate-size distribution in the Tarim Basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Tarim Basin is an important source of airborne particulate matter that contributes to poor air quality in China. However, little attention has been given to estimating wind erodibility of soils in the region. The objective of this study was to determine the soil wind erodibility for six land use...

  1. Particle size distribution of eroded material from semi-arid soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The particle size distribution (PSD) of eroded sediments can be used to deduce potential nutrient losses, pollution hazards and the redistribution of soil components over the landscape. We studied eroded sediments from three semi-arid soils, with different clay contents, that were wetted at a slow (...

  2. Developing soil erodibility prediction equations for the Rangeland Hydrology and Erosion Model (RHEM)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by apply...

  3. Dedicated bioenergy crop impacts on soil wind erodibility and organic carbon in Kansas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dedicated bioenergy crops such as perennial warm-season grasses (WSGs) may reduce soil erosion and improve soil properties while providing biomass feedstock for biofuel. We quantified impacts of perennial WSGs and row crops on soil wind erodibility parameters (erodible fraction, geometric mean diame...

  4. Erodibility of selected soils and estimates of sediment yields in the San Juan Basin, New Mexico

    USGS Publications Warehouse

    Summer, Rebecca M.

    1981-01-01

    Onsite rainfall-simulation experiments were conducted to derive field-erodibility indexes for rangeland soils and soils disturbed by mining in coal fields of northwestern New Mexico. Mean indexes on rangeland soils range from 0 grams (of detached soil) on dune soil to 121 grams on wash-transport zones. Mean field-erodibility-index values of soils disturbed by mining range from 16 to 32 grams; they can be extrapolted to nearby coal fields where future mining is expected. Because field-erodibility-index data allow differentiation of erodibilities across a variable landscape, these indexes were used to adjust values of K, the erodibility factor of the Universal Soil Loss Equation. Estimates of soil loss and sediment yield were then calculated for a small basin following mining. (USGS)

  5. Aluminum bioconcentration at the gill surface of juvenile Atlantic salmon in acidic media

    SciTech Connect

    Wilkinson, K.J.; Campbell, P.G.C. . INRS-Eau)

    1993-11-01

    Aluminum uptake by Atlantic salmon was examined in the laboratory at pH 4.5, under conditions similar to those found in running waters on the Canadian Precambrian Shield during spring snowmelt. Gill uptake of Al was slow, approaching steady state only after 3 d of exposure. The greatest fraction of gill-associated Al was sorbed not to the gill surface itself, but to the gill mucus. Mucus appears to retard Al transport from solution to the membrane surface, thus delaying the acute biological response of the fish. Strongly associated gill [Al] was never greater than 10% of total gill Al in the early stages of the experiment indicated that this Al fraction could eventually exceed 50% of the total gill Al. In contrast to uptake, depuration of Al was extremely rapid; total gill [Al] of fish exposed to Al (pH 4.5) for 2 d decreased by 60% after only 2 h in an Al-free medium. The effect of fluoride complexation on Al bioconcentration was also examined. For equivalent Al[sup 3]+ concentrations, sorption of Al to the gill surface was higher in the presence of fluoride than in its absence, which suggests the formation of mixed ligand [F-Al-L-gill] complexes at the gill surface.

  6. Salmon Gill Poxvirus, the Deepest Representative of the Chordopoxvirinae

    PubMed Central

    Yutin, Natalya; Tengs, Torstein; Senkevich, Tania; Koonin, Eugene; Rønning, Hans Petter; Alarcon, Marta; Ylving, Sonja; Lie, Kai-Inge; Saure, Britt; Tran, Linh; Dale, Ole Bendik

    2015-01-01

    ABSTRACT Poxviruses are large DNA viruses of vertebrates and insects causing disease in many animal species, including reptiles, birds, and mammals. Although poxvirus-like particles were detected in diseased farmed koi carp, ayu, and Atlantic salmon, their genetic relationships to poxviruses were not established. Here, we provide the first genome sequence of a fish poxvirus, which was isolated from farmed Atlantic salmon. In the present study, we used quantitative PCR and immunohistochemistry to determine aspects of salmon gill poxvirus disease, which are described here. The gill was the main target organ where immature and mature poxvirus particles were detected. The particles were detected in detaching, apoptotic respiratory epithelial cells preceding clinical disease in the form of lethargy, respiratory distress, and mortality. In moribund salmon, blocking of gas exchange would likely be caused by the adherence of respiratory lamellae and epithelial proliferation obstructing respiratory surfaces. The virus was not found in healthy salmon or in control fish with gill disease without apoptotic cells, although transmission remains to be demonstrated. PCR of archival tissue confirmed virus infection in 14 cases with gill apoptosis in Norway starting from 1995. Phylogenomic analyses showed that the fish poxvirus is the deepest available branch of chordopoxviruses. The virus genome encompasses most key chordopoxvirus genes that are required for genome replication and expression, although the gene order is substantially different from that in other chordopoxviruses. Nevertheless, many highly conserved chordopoxvirus genes involved in viral membrane biogenesis or virus-host interactions are missing. Instead, the salmon poxvirus carries numerous genes encoding unknown proteins, many of which have low sequence complexity and contain simple repeats suggestive of intrinsic disorder or distinct protein structures. IMPORTANCE Aquaculture is an increasingly important global

  7. Procedures for the reconstruction, primary culture and experimental use of rainbow trout gill epithelia.

    PubMed

    Schnell, Sabine; Stott, Lucy C; Hogstrand, Christer; Wood, Chris M; Kelly, Scott P; Pärt, Peter; Owen, Stewart F; Bury, Nic R

    2016-03-01

    This protocol describes how to reconstruct and culture the freshwater rainbow trout gill epithelium on flat permeable membrane supports within cell culture inserts. The protocol describes gill cell isolation, cultured gill epithelium formation, maintenance, monitoring and preparation for use in experimental procedures. To produce a heterogeneous gill epithelium, as seen in vivo, seeding of isolated gill cells twice over a 2-d period is required. As a consequence, this is termed the double-seeded insert technique. Approximately 5-12 d after cell isolation and seeding, preparations develop electrically tight gill epithelia that can withstand freshwater on the apical cell surface. The system can be used to study freshwater gill physiology, and it is a humane alternative for toxicity testing, bioaccumulation studies and environmental water quality monitoring. PMID:26866792

  8. Differential expression of gill Na+,K+-ATPaseα - and β-subunits, Na+,K+,2Cl- cotransporter and CFTR anion channel in juvenile anadromous and landlocked Atlantic salmon Salmo salar

    USGS Publications Warehouse

    Nilsen, Tom O.; Ebbesson, Lars O.E.; Madsen, Steffen S.; McCormick, Stephen D.; Andersson, Eva; Bjornsson, Bjorn Thrandur; Prunet, Patrick; Stefansson, Sigurd O.

    2007-01-01

    This study examines changes in gill Na+,K+-ATPase (NKA) α- and β-subunit isoforms, Na+,K+,2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR I and II) in anadromous and landlocked strains of Atlantic salmon during parr-smolt transformation, and after seawater (SW) transfer in May/June. Gill NKA activity increased from February through April, May and June among both strains in freshwater (FW), with peak enzyme activity in the landlocked salmon being 50% below that of the anadromous fish in May and June. Gill NKA-α1b, -α3, -β1 and NKCC mRNA levels in anadromous salmon increased transiently, reaching peak levels in smolts in April/May, whereas no similar smolt-related upregulation of these transcripts occurred in juvenile landlocked salmon. Gill NKA-α1a mRNA decreased significantly in anadromous salmon from February through June, whereas α1a levels in landlocked salmon, after an initial decrease in April, remained significantly higher than those of the anadromous smolts in May and June. Following SW transfer, gill NKA-α1b and NKCC mRNA increased in both strains, whereas NKA-α1a decreased. Both strains exhibited a transient increase in gill NKA α-protein abundance, with peak levels in May. Gill α-protein abundance was lower in SW than corresponding FW values in June. Gill NKCC protein abundance increased transiently in anadromous fish, with peak levels in May, whereas a slight increase was observed in landlocked salmon in May, increasing to peak levels in June. Gill CFTR I mRNA levels increased significantly from February to April in both strains, followed by a slight, though not significant increase in May and June. CFTR I mRNA levels were significantly lower in landlocked than anadromous salmon in April/June. Gill CFTR II mRNA levels did not change significantly in either strain. Our findings demonstrates that differential expression of gill NKA-α1a, -α1b and -α3 isoforms may be important for potential functional

  9. What is the primary function of the early teleost gill? Evidence for Na+/NH+4 exchange in developing rainbow trout (Oncorhynchus mykiss)

    PubMed Central

    Zimmer, Alex M.; Wright, Patricia A.; Wood, Chris M.

    2014-01-01

    Post-hatch fishes lack a functional gill and use cutaneous surfaces for exchange with the surrounding environment. The ionoregulatory hypothesis posits that ionoregulation is the first physiological process to be limited by cutaneous exchange, necessitating its shift to the gills. We hypothesized that the ontogeny of branchial ammonia excretion (Jamm) is coupled to Na+ uptake () in accordance with the current model for exchange in freshwater. Using divided chambers, branchial and cutaneous Jamm, and oxygen consumption (MO2) by larval rainbow trout were assessed. Following hatch, the skin accounted for 97% and 86% of total Jamm and , respectively. Jamm and shifted to the gills simultaneously at 15 days post-hatch (dph) and were highly correlated (R2 = 0.951) at the gills, but not the skin, over development. Contrastingly, MO2 shifted significantly later at 27 dph, in agreement with the ionoregulatory hypothesis. Moreover, the mRNA expression and/or enzymatic activity of Rhesus proteins, Na+/H+-exchanger, H+-ATPase, Na+/K+-ATPase and carbonic anhydrase, all key components of the -exchange system, increased in the gills over larval development. We propose that the ontogeny of branchial occurs as exchange and provide evidence for a novel element to the ionoregulatory hypothesis, the excretion of potentially lethal metabolic ammonia. PMID:25274361

  10. Tralopyril bioconcentration and effects on the gill proteome of the Mediterranean mussel Mytilus galloprovincialis.

    PubMed

    Oliveira, Isabel B; Groh, Ksenia J; Stadnicka-Michalak, Julita; Schönenberger, René; Beiras, Ricardo; Barroso, Carlos M; Langford, Katherine H; Thomas, Kevin V; Suter, Marc J-F

    2016-08-01

    Antifouling (AF) systems are used worldwide as one of the most cost-effective ways of protecting submerged structures against heavy biofouling. The emergence of environmentally friendly AF biocides requires knowledge on their environmental fate and toxicity. In this study we measured the bioconcentration of the emerging AF biocide tralopyril (TP) in the Mediterranean mussel Mytilus galloprovincialis and investigated the effects of TP on the mussel gill proteome following acute (2days) and chronic (30days) exposure, as well as after a 10-day depuration period. The experiments were carried out with 1μg/L TP; blank and solvent (5×10(-5)% DMSO) controls were also included. Proteomics analysis was performed by mass spectrometry-based multidimensional protein identification technology (MudPIT). Differentially expressed proteins were identified using a label-free approach based on spectral counts and G-test. Our results show that TP is rapidly accumulated by mussels at concentrations up to 362ng/g dw (whole tissues), reaching steady-state condition within 13days. Ten days of depuration resulted in 80% elimination of accumulated TP from the organism, suggesting that a complete elimination could be reached with longer depuration times. In total, 46 proteins were found to be regulated in the different exposure scenarios. Interestingly, not only TP but also DMSO alone significantly modulated the protein expression in mussel gills following acute and chronic exposure. Both compounds regulated proteins involved in bioenergetics, immune system, active efflux and oxidative stress, often in the opposite way. Alterations of several proteins, notably several cytoskeletal ones, were still observed after the depuration period. These may reflect either the continuing chemical effect due to incomplete elimination or an onset of recovery processes in the mussel gills. Our study shows that exposure of adult mussels to sublethal TP concentration results in the bioconcentration of this

  11. Relationship between soil erodibility and modeled infiltration rate in different soils

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Fang, Qingqing; Wu, Binbin; Yang, Huicai; Xu, Zongxue

    2015-09-01

    The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Here, the soil erodibility factors (K and Ke in the USLE, Ki and K1 in the WEPP) were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The impacts of compost amendment on the soil erosion characteristics and relationship were also studied. Two contrasting agricultural soils (bare and cultivated fluvo-aquic soils) were used, and different poultry compost contents (control, low and high) were applied to both soils. The results indicated that the runoff rate, sediment yield rate and soil erodibility of the bare soil treatments were generally higher than those of the corresponding cultivated soil treatments. The application of composts generally decreased sediment yield and soil erodibility but did not always decrease runoff. The comparison of measured and modeled infiltration rates indicated that the model represented the infiltration processes well with an N-S coefficient of 0.84 for overall treatments. Significant negative logarithmic correlations have been found between final infiltration rate (FIR) and the four soil erodibility factors, and the relationship between USLE-K and FIR demonstrated the best correlation. The application of poultry composts would not influence the logarithmic relationship between FIR and soil erodibility. Our study provided a useful tool to estimate soil erodibility.

  12. An improved girthometer for studies of gill net selectivity

    USGS Publications Warehouse

    Wydoski, Richard S.; Wolfert, David R.

    1968-01-01

    Gill nets are effective for collecting samples of many fish species. These nets may be highly selective in their catch, depending on the mesh size or sizes used and on the size distribution and body shape of the fish in the population. Early studies related mesh selectivity to length or, in a few instances, to length and weight. Later studies showed that the selectivity of gill nets was related more closely to the girth of the fish than to the length, weight, or a combination of these. The girthometer presented here was designed for rapid and accurate measurement of the fish girth. Both speed and accuracy are important when very large numbers of fish are sampled for mesh-selectivity studies. It is also important that a girthometer be sturdy and rigid enough to provide accurate measurements in spite of rough handling and difficult working conditions.

  13. Enhanced habit formation in Gilles de la Tourette syndrome.

    PubMed

    Delorme, Cécile; Salvador, Alexandre; Valabrègue, Romain; Roze, Emmanuel; Palminteri, Stefano; Vidailhet, Marie; de Wit, Sanne; Robbins, Trevor; Hartmann, Andreas; Worbe, Yulia

    2016-02-01

    Tics are sometimes described as voluntary movements performed in an automatic or habitual way. Here, we addressed the question of balance between goal-directed and habitual behavioural control in Gilles de la Tourette syndrome and formally tested the hypothesis of enhanced habit formation in these patients. To this aim, we administered a three-stage instrumental learning paradigm to 17 unmedicated and 17 antipsychotic-medicated patients with Gilles de la Tourette syndrome and matched controls. In the first stage of the task, participants learned stimulus-response-outcome associations. The subsequent outcome devaluation and 'slip-of-action' tests allowed evaluation of the participants' capacity to flexibly adjust their behaviour to changes in action outcome value. In this task, unmedicated patients relied predominantly on habitual, outcome-insensitive behavioural control. Moreover, in these patients, the engagement in habitual responses correlated with more severe tics. Medicated patients performed at an intermediate level between unmedicated patients and controls. Using diffusion tensor imaging on a subset of patients, we also addressed whether the engagement in habitual responding was related to structural connectivity within cortico-striatal networks. We showed that engagement in habitual behaviour in patients with Gilles de la Tourette syndrome correlated with greater structural connectivity within the right motor cortico-striatal network. In unmedicated patients, stronger structural connectivity of the supplementary motor cortex with the sensorimotor putamen predicted more severe tics. Overall, our results indicate enhanced habit formation in unmedicated patients with Gilles de la Tourette syndrome. Aberrant reinforcement signals to the sensorimotor striatum may be fundamental for the formation of stimulus-response associations and may contribute to the habitual behaviour and tics of this syndrome. PMID:26490329

  14. Optimization of a Cytochrome-P450-Monooxygenase-1A-Mediated EROD Assay in the Cape Hake Species Merluccius capensis and Merluccius paradoxus (Pisces)

    PubMed Central

    De Almeida, Louise; Froneman, William; Pletschke, Brett

    2011-01-01

    Cytochrome P450 monooxygenase 1A (CYP1A) is induced by several planar toxic compounds, for example, polychlorinated biphenyls (PCBs) and the induction of this protein is often measured in terms of CYP1A-mediated 7-ethoxyresorufin-O-deethylase (EROD) activity. This study was aimed at developing this assay in the Cape hake species Merluccius capensis and Merluccius paradoxus (considered one stock). Microsomal fractions were obtained from frozen fish liver samples by differential centrifugation. Fluorimetric and spectrophotometric analysis of the EROD assay resulted in the spectrophotometric (at 572 nm) detection method being selected, as this method resulted in a lower degree of variability and demonstrated higher reproducibility. The activity in the EROD assay was enhanced in the presence of NADPH, and the addition of dicumarol (phase II enzyme inhibitor) to the reaction mixtures prevented the underestimation of this assay by the inhibition of DT-diaphorase. In summary, an EROD assay was established for use in Cape hake species. PMID:22145075

  15. L-alanine uptake in membrane vesicles from Mytilus edulis gills

    SciTech Connect

    Pajor, A.M.; Wright, S.H.

    1986-03-05

    Previous studies have shown that gills from M. edulis can accumulate L-alanine from seawater by a saturable process specific for ..cap alpha..-neutral amino acids. This uptake occurs against chemical gradients in excess of 10/sup 6/ to 1. To further characterize this uptake, membrane vesicles were prepared from M. edulis gill tissue by differential centrifugation. Enrichments of putative enzyme markers (relative to that in combined initial fractions) were as follows: ..gamma..-Glutamyltranspeptidase, 25-30x; Alkaline Phosphatase, 5-6x; K/sup +/-dependent para-Nitrophenyl Phosphatase, 3-5x; Succinate Dehydrogenase 0.1-0.2x. These results suggest that the preparation is enriched in plasma membranes, although histochemical studies will be needed to verify this. The time course of /sup 14/C-L-alanine uptake in the presence of inwardly-directed Na/sup +/ gradient showed a transient overshoot (3-5 fold) at 10 minutes which decreased to equilibrium after six hours. The size of the overshoot and early uptake rates depended on the size of the inwardly-directed Na/sup +/ gradient. No overshoot was seen in the presence of inwardly-directed gradients of LiCl or choline-Cl, or with equilibrium concentrations NaCl or mannitol. A reduced overshoot was seen with a gradient of NaSCN. A small overshoot was seen with an inwardly-directed gradient of KCl. Transport of L-alanine included saturable and diffusive components. Uptake of 6 ..mu..M L-alanine was inhibited more than 80% by 100 ..mu..M ..cap alpha..-zwitterionic amino acids (alanine, leucine, glycine); by 30 to 75% by proline, aspartate and lysine; and less than 20% by a ..beta..-amino acid, taurine. The results of these experiments agree with those from intact gill studies and support the hypothesis that L-alanine is transported into gill epithelial cells by a secondary active transport process involving Na/sup +/.

  16. Famous people with Gilles de la Tourette syndrome?

    PubMed

    Monaco, Francesco; Servo, Serena; Cavanna, Andrea Eugenio

    2009-12-01

    Virtually no neurologist nor psychiatrist today can be unaware of the diagnosis of Gilles de la Tourette syndrome (GTS). Although the eponymous description by Dr. Georges Gilles de la Tourette was published in 1885, familiarity with this syndrome has been achieved only recently. In this article, the two most renown accounts of exceptional individuals retrospectively diagnosed with GTS are critically analyzed: British lexicographer Samuel Johnson and Austrian musician Wolfgang Amadeus Mozart. In both cases, clinical descriptions have been retrieved from written documents predating Gilles de la Tourette's original publication. The case for Samuel Johnson having GTS is strong, mainly based on Boswell's extensive biographical account. Johnson was reported to have a great range of tics and compulsions, including involuntary utterances, repetitive ejaculations, and echo-phenomena. On the other hand, there is circumstantial evidence that Mozart may have had hyperactivity, restlessness, sudden impulses, odd motor behaviors, echo/palilalia, love of nonsense words, and scatology, the latter being documented in autograph letters ("coprographia"). However, the evidence supporting the core features of GTS, i.e., motor and vocal tics, is rather inconsistent. Thus, GTS seems to be an implausible diagnosis in Mozart's medical history and completely unrelated to his undisputed musical genius. PMID:19913652

  17. Reynolds number effects on gill pumping mechanics in mayfly nymphs

    NASA Astrophysics Data System (ADS)

    Sensenig, Andrew; Shultz, Jeffrey; Kiger, Ken

    2006-11-01

    Mayfly nymphs have an entirely aquatic life stage in which they frequently inhabit stagnant water. Nymphs have the capability to generate a ventilation current to compensate for the low oxygen level of the water by beating two linear arrays of plate-like gills that typically line the lateral edge of the abdomen. The characteristic Reynolds number associated with the gill motion changes with animal size, varying over a span of Re = 5 to 100 depending on age and species. The assumption that the system maintains optimal energetic efficiency leads to the prediction that animals transition from rowing to flapping mechanisms with increasing Re, while possibly utilizing a squeeze mechanism to a greater extent at lower Re. To investigate this hypothesis, we capture the motion of the gills through 3D imaging to investigate the effect of Reynolds number on the stroke patterns. PIV is utilized to assess flow rates and viscous dissipation. The effectiveness of the ventilation mechanism at each size has important consequences for the range of oxygen levels, and hence the habitat range, that can be tolerated by that size.

  18. Intracellular Oceanospirillales bacteria inhabit gills of Acesta bivalves.

    PubMed

    Jensen, Sigmund; Duperron, Sébastien; Birkeland, Nils-Kåre; Hovland, Martin

    2010-12-01

    A novel bacterium was discovered in the gills of the large bivalve Acesta excavata (Limidae) from coral reefs on the northeast Atlantic margin near the shelf break of the fishing ground Haltenbanken of Norway, and confirmed present in A. excavata from a rock-wall in the Trondheimsfjord. Purified gill DNA contained one dominant bacterial rRNA operon as indicated from analysis of broad range bacterial PCR amplicons in denaturant gradient gels, in clone libraries and by direct sequencing. The sequences originated from an unknown member of the order Oceanospirillales and its 16S rRNA gene fell within a clade of strictly marine invertebrate-associated Gammaproteobacteria. Visual inspection by fluorescent in situ hybridization and transmission electron microscopy indicated a pleomorphic bacterium with no visible cell wall, located in aggregates inside vacuoles scattered within the gill cells cytoplasm. Intracellular Oceanospirillales exist in bathymodiolin mussels (parasites), Osedax worms and whiteflies (symbionts). This bacterium apparently lives in a specific association with the Acesta. PMID:21044098

  19. In vivo effects of Aphanizomenon flos-aquae DC-1 aphantoxins on gas exchange and ion equilibrium in the zebrafish gill.

    PubMed

    Zhang, Delu; Liu, Siyi; Zhang, Jing; Zhang, Jian Kong; Hu, Chunxiang; Liu, Yongding

    2016-08-01

    Aphantoxins, neurotoxins or paralytic shellfish poisons (PSPs) generated by Aphanizomenon flos-aquae, are a threat to environmental safety and human health in eutrophic waters worldwide. The molecular mechanisms of neurotoxin function have been studied; however, the effects of these neurotoxins on oxidative stress, ion transport, gas exchange, and branchial ultrastructure in fish gills are not fully understood. Aphantoxins extracted from A. flos-aquae DC-1 were detected by high-performance liquid chromatography. The major ingredients were gonyautoxins 1 and 5 and neosaxitoxin, which comprised 34.04%, 21.28%, and 12.77% of the total, respectively. Zebrafish (Danio rerio) were administered A. flos-aquae DC-1 aphantoxins at 5.3 or 7.61μg saxitoxin equivalents (eq)/kg (low and high doses, respectively) by intraperitoneal injection. The activities of Na(+)-K(+)-ATPase (NKA), carbonic anhydrase (CA), and lactate dehydrogenase (LDH), ultrastructural alterations in chloride and epithelial cells, and reactive oxygen species (ROS) and total antioxidative capacity (T-AOC) were investigated in the gills during the first 24h after exposure. Aphantoxins significantly increased the level of ROS and decreased the T-AOC in zebrafish gills from 3 to 12h post-exposure, suggesting an induction of oxidative stress and inhibition of antioxidant capacity. Reduced activities of NKA and CA demonstrated abnormal ion transport and gas exchange in the gills of aphantoxin-treated fish. Toxin administration also resulted in increased LDH activity and ultrastructural alterations in chloride and epithelial cells, suggesting a disruption of function and structure in zebrafish gills. The observed abnormalities in zebrafish gills occurred in a time- and dose-dependent manner. These findings demonstrate that aphantoxins or PSPs may inhibit ion transport and gas exchange, increase LDH activity, and result in ultrastructural damage to the gills through elevations in oxidative stress and reduced

  20. Seasonal variation of oxidative biomarkers in gills and digestive gland of green-lipped mussel Perna viridis from Arabian Sea

    NASA Astrophysics Data System (ADS)

    Verlecar, X. N.; Jena, K. B.; Chainy, G. B. N.

    2008-03-01

    Investigations on seasonal variation in oxidative stress biomarkers were carried out on the natural population of green-lipped mussel Perna viridis collected from Bambolim beach area of Goa. Oxidative stress indices such as lipid peroxidation (LPX), hydrogen peroxide (H 2O 2), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione transferase (GST), glutathione reductase (GR), reduced glutathione (GSH) and ascorbic acid (ASA) were measured in gills and digestive gland of P. viridis during February, May, August and November. The present study reveals two important aspects regarding the antioxidant defence status of tissues of P. viridis. Firstly, antioxidant capacity of tissues of P. viridis exhibits seasonal variation. Secondly, various components of antioxidant capacity such as oxidative stress markers, levels of antioxidant enzymes and small antioxidant molecules vary differently in tissues with respect to different seasons. Although the oxidative stress status of gills and digestive gland of P. viridis expressed in terms of LPX and H 2O 2 was the lowest in February, its level was maximal in gills and digestive gland during May and November, respectively. While activities of SOD and GPX of tissues of P. viridis were found to be low in August, activities of CAT and GR were recorded to be low in February. GST activity in gills although remained high in February, in digestive gland elevated values were recorded in August and November. A seasonal variation in the levels of small antioxidant molecules was also noticed. Among non enzymatic antioxidants ASA content of tissues was maximal in May and August in comparison to February and November, but GSH remained high in November. It therefore appears that environmental factors may play a crucial role in regulating the oxidative stress capacity of tissues of P. viridis.

  1. GETS (GILL EXCHANGE OF TOXIC SUBSTANCES), A SIMULATION MODEL FOR DYNAMIC BIOACCUMULATION OF NONPOLAR ORGANICS BY GILL EXCHANGE: A USER'S GUIDE

    EPA Science Inventory

    A Fortran program that estimates the absorption and depuration of a chemical across fish gills is described. The program is based on a set of diffusion and forced convection differential equations. Gill morphometric parameters are computed by the program via its own internal data...

  2. Functional morphology of the gills of the shortfin mako, Isurus oxyrinchus, a lamnid shark.

    PubMed

    Wegner, Nicholas C; Sepulveda, Chugey A; Olson, Kenneth R; Hyndman, Kelly A; Graham, Jeffrey B

    2010-08-01

    This study examines the functional gill morphology of the shortfin mako, Isurus oxyrinchus, to determine the extent to which its gill structure is convergent with that of tunas for specializations required to increase gas exchange and withstand the forceful branchial flow induced by ram ventilation. Mako gill structure is also compared to that of the blue shark, Prionace glauca, an epipelagic species with lower metabolic requirements and a reduced dependence on fast, continuous swimming to ventilate the gills. The gill surface area of the mako is about one-half that of a comparably sized tuna, but more than twice that of the blue shark and other nonlamnid shark species. Mako gills are also distinguished from those of other sharks by shorter diffusion distances and a more fully developed diagonal blood-flow pattern through the gill lamellae, which is similar to that found in tunas. Although the mako lacks the filament and lamellar fusions of tunas and other ram-ventilating teleosts, its gill filaments are stiffened by the elasmobranch interbranchial septum, and the lamellae appear to be stabilized by one to two vascular sacs that protrude from the lamellar surface and abut sacs of adjacent lamellae. Vasoactive agents and changes in vascular pressure potentially influence sac size, consequently effecting lamellar rigidity and both the volume and speed of water through the interlamellar channels. However, vascular sacs also occur in the blue shark, and no other structural elements of the mako gill appear specialized for ram ventilation. Rather, the basic elasmobranch gill design and pattern of branchial circulation are both conserved. Despite specializations that increase mako gill area and efficacy relative to other sharks, the basic features of the elasmobranch gill design appear to have limited selection for a larger gill surface area, and this may ultimately constrain mako aerobic performance in comparison to tunas. PMID:20623624

  3. Pioneers of movement disorders: Georges Gilles de la Tourette.

    PubMed

    Krämer, H; Daniels, C

    2004-06-01

    Georges Albert Edouard Brutus Gilles de la Tourette (1857-1904), a French neurologist and pupil of Jean Martin Charcot at the Salpêtrière hospital in Paris, has gained common recognition through his description of the 'Maladie des Tics'. This complex neuropsychiatric disorder, later known as the 'Tourette's syndrome', nowadays is accepted as a specific entity of movement disorders. Gilles had started working under Charcot (1825-1893), the first physician to occupy a designated chair of neurology of neuropsychiatric history, in 1884. Then the Salpêtrière hospital was a centre of intensive research with an emphasis on hysteria and hypnosis. Tourette took an interest in hysteria, but also dedicated himself to various other neuropsychiatric disorders and to neuropathology. He published scientific works on epilepsia, neurasthenia and syphilitic myelitis. Although he devoted much time to his neuropsychiatric research and the publication of articles in medical journals, his career did not make significant progress, despite Charcot's unrestricted support. One reason was, that he disregarded questions, answers and problems, which were outside his interest fields. Hence, he was accused for having acquired an extremely filtered and one-sided knowledge. Also, his alienated and critical behaviour, which had not helped him to find many friends over the years, prevented him from professional promotion. In 1893 an assassination attempt on Gilles de la Tourette raised considerable public interest: Gilles was shot in his appartement in the Rue de l'Université 39 by a young woman, who had been his patient in the Salpêtrière and who claimed that she had been hypnotized without her agreement and thereby had lost her mental health. However, the patient was diagnosed with a disease nowadays called paranoid schizophrenia and therefore hypnosis was not attributed to any part of the disease. Due to episodes of melancholia and phases of delusions of grandeur and megalomania Gilles de

  4. in vitro effects of cadmium and lead on ATPases in the gill of the rock crab, Cancer irroratus

    SciTech Connect

    Tucker, R.K.; Matte, A.

    1980-06-01

    In this study with the rock crab, Cancer irroratus, the effects of lead and cadmium on enzymes in the gill are studied. This organ is intimately involved in osmoregulation as well as respiration in the estuarine animal. Metal uptake studies with crustacea have shown high initial concentrations in gill tissue. Sodium-potassium-ATPase is a key enzyme in cellular water balance and in osmoregulation in the whole animal. The membrane bound gill Na/sup +/-K/sup +/ATPase, being intimately exposed to the aqueous environment, seemed an excellent candidate for testing effects of environmentally occurring heavy metals. As part of the enzyme assay procedure, the activity of other ATPases present in the tissue preparations was also determined. Some of this ATPase activity is mirochondrial and important in cellular energy metabolism. While mitochondrial enzyme exposure to environmental heavy metals may be less direct than that of cellular membrane enzyme, their inhibition could have equally detrimental effects on the function of the total organism.

  5. Effect of salinity on the biosynthesis of amines in Litopenaeus vannamei and the expression of gill related ion transporter genes

    NASA Astrophysics Data System (ADS)

    Pan, Luqing; Liu, Hongyu; Zhao, Qun

    2014-06-01

    This study examined the effect of salinity on the expression of Na+/K+-ATPase (NKA) α-subunit and vacuolar-type H+-ATPase (V-ATPase) β-subunit gene in the gill of Litopenaeus vannamei. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) assay showed that the expression of NKA α-subunit and V-ATPase β-subunit gene was significantly influenced by salinity. It was found that the NKA activity significantly varied with salinity in time and dose dependent manner; whereas the V-ATPase activity did not. The abundance of NKA α-subunit gene transcript increased rapidly when the salinity decreased from 26b to 21, and slowly when the salinity decreased from 26 to 31 within the first 24 h. When the salinity decreased from 26 to 21, the transcription of NKA α-subunit gene in gill epithelium was higher at 12 h than that at 0 h, which was consistent with the result of immunoblotting assay of NKA α-subunit. In addition, salinity had a significant time- and dose-dependent effect on the concentration of biogenic amines in both hemolymph and gill. As compared to other parameters, the concentration of dopamine (DA) and 5-hydroxytryptamine (5-HT) varied in different patterns when the salinity decreased from 26 to 21 or increased from 26 to 31, suggesting that DA and 5-HT played different regulatory roles in osmotic adaption and modulation of shrimp when salinity varies.

  6. A new method to determine eroded areas in arid environment using Landsat satellite imagery

    NASA Astrophysics Data System (ADS)

    A, Aydda; Ah, Algouti; Ab, Algouti; M, Essemani; Y, Taghya

    2014-06-01

    Erosion (by water or wind) is an increasing problem for many local authorities and government agencies throughout the world. The identification of eroded areas in arid and humid regions can be very useful for environmental planning and can help reduce soil and sediment degradation in these regions. In this work we present a new method to determine eroded areas in arid environment. In this method were explored lithological data to determine eroded areas. These data were collected in the field using GPS (Global Positioning System) checkpoints and geological maps. For that, two lithological maps of the study areas were analysed to determine lithological data change. Those two maps were obtained from the classification algorithm by applying the maximum likelihood on two Landsat satellite images. After images classification and validation a change detection technique was adopted to determine eroded areas. This method was applied in northern part of Atlantic Sahara desert to confirm their potentiality.

  7. Determining Relative Contributions of Eroded Landscape Sediment and Bank Sediment to the Suspended Load of Streams and Wetlands Using 7Be and 210Pbxs

    NASA Astrophysics Data System (ADS)

    Wilson, C.; Matisoff, G.; Whiting, P.; Kuhnle, R.

    2005-12-01

    The naturally occurring radionuclides, 7Be and 210Pbxs, have been used individually as tracers of sediment particles throughout watersheds. However, use of the two radionuclides together enables eliciting information regarding the major contributors of fine sediment to the suspended load of a stream or wetland. We report on a study that uses these radionuclides to quantify the relative proportion of eroded surface soils, bank material and resuspended bed sediment in the fine suspended sediment load of the Goodwin Creek, MS, and Old Woman Creek, OH watersheds. The eroded surface soil has a unique radionuclide signature relative to the bed sediments in Old Woman Creek and the bank material along Goodwin Creek that allows for the quantification of the relative proportions of the different sediments in the sediment load. In Old Woman Creek, the different signatures are controlled by the differential decay of the two radionuclides. In Goodwin Creek, the different signatures are due to different erosion processes controlling the sediment delivery to streams, namely sheet erosion and bank collapse. The eroded surface soils will have higher activities of the 7Be and 210Pbxs than bed/bank sediments. The fine suspended sediment, which is a mixture of eroded surface soils and resuspended bed sediment or collapsed bank sediment, will have an intermediate radionuclide signature quantified in terms of the relative proportion from both sediments. A simple two-end member mixing model is used to determine the relative proportions of both sediments to the total fine sediment load.

  8. An assessment of the erodibility of Holocene lithounits comprising streambanks in northeastern Kansas, USA

    NASA Astrophysics Data System (ADS)

    Layzell, Anthony L.; Mandel, Rolfe D.

    2014-05-01

    Streambanks are the primary source of sediment for watersheds in the Midwestern USA. In much of this region, deposits of fine-grained Holocene alluvium comprising streambanks have been assigned to a single lithostratigraphic unit, the DeForest Formation. This study examines the stratigraphic relationships and measures the erodibility of the different members of the DeForest Formation in three watersheds in northeastern Kansas. Distinct differences in erodibility, measured in terms of critical shear stress (τc) by a submerged jet-test device, were observed between the different members of the DeForest Formation. The most erodible member is the Camp Creek Member (average τc = 1.0 Pa) while the most resistant is the Gunder Member (average τc = 10.4 Pa). Variability in erodibility between and within the members of the DeForest Formation is attributed to the magnitude of post-depositional soil-forming processes, including the presence of buried soils, as well as the inherent natural variability in the different parent materials. A weak positive correlation was found between percent clay and τc. Resistance to erosion by fluid flow was found to be significantly greater where clay contents exceed 28%. Although the Camp Creek Member was found to be the most erodible, it always occurs, stratigraphically, as the uppermost member. Available bankfull stage indicators suggest that bankfull discharges rarely attain elevations sufficient to erode Camp Creek Member deposits. Therefore, other members of the DeForest Formation are able to exert some control on the rate of bank erosion by hydraulic flow. Furthermore, given the observed differences in lithology, soil development and erodibility, the susceptibility to mass wasting processes is also likely to vary between the different members. Therefore, lithostratigraphic and soil-stratigraphic relationships have important implications for streambank erodibility and are crucial for accurately determining areas prone to streambank

  9. Effects of hypoxia on ionic regulation, glycogen utilization and antioxidative ability in the gills and liver of the aquatic air-breathing fish Trichogaster microlepis.

    PubMed

    Huang, Chun-Yen; Lin, Hui-Chen; Lin, Cheng-Huang

    2015-01-01

    We examined the hypothesis that Trichogaster microlepis, a fish with an accessory air-breathing organ, uses a compensatory strategy involving changes in both behavior and protein levels to enhance its gas exchange ability. This compensatory strategy enables the gill ion-regulatory metabolism to maintain homeostasis during exposure to hypoxia. The present study aimed to determine whether ionic regulation, glycogen utilization and antioxidant activity differ in terms of expression under hypoxic stresses; fish were sampled after being subjected to 3 or 12h of hypoxia and 12h of recovery under normoxia. The air-breathing behavior of the fish increased under hypoxia. No morphological modification of the gills was observed. The expression of carbonic anhydrase II did not vary among the treatments. The Na(+)/K(+)-ATPase enzyme activity did not decrease, but increases in Na(+)/K(+)-ATPase protein expression and ionocyte levels were observed. The glycogen utilization increased under hypoxia as measured by glycogen phosphorylase protein expression and blood glucose level, whereas the glycogen content decreased. The enzyme activity of several components of the antioxidant system in the gills, including catalase, glutathione peroxidase, and superoxidase dismutase, increased in enzyme activity. Based on the above data, we concluded that T. microlepis is a hypoxia-tolerant species that does not exhibit ion-regulatory suppression but uses glycogen to maintain energy utilization in the gills under hypoxic stress. Components of the antioxidant system showed increased expression under the applied experimental treatments. PMID:25218942

  10. Evolution of potentially eroding events along the northern coast of the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Rasilla Álvarez, D.; García Codrón, J. C.

    2009-09-01

    The anthropogenic global warming is expected to result in a rise in sea-level, accompanied by changes in extreme climate events, such as the frequency and intensity of storms. Such scenario would result in an acceleration of coastal erosion. The aim of the present study is to assess the temporal evolution of potentially eroding events along the northern coast of the Iberian Peninsula during the second half of the 20th century, and to investigate changes in forcing processes such as the frequency and magnitude of storm surges and high wave events. To characterize the potentially eroding events, the total elevation of the water level was selected, being calculated as the sum of the contributions of the average water level, wave run up and the storm surges. Potentially eroding events were identified and quantified following a two-step procedure. Through the first step the potential flood induced by a given storm was estimated by simulating its effects on a theoretical beach profile (intermediate) using an empirical parameterization for extreme run-up approach. The second step consisted on characterizing the maximum storm surge registered during a storm. Those parameters were calculated from hindcasted data (storm surge, wave heights and period, wind speed and direction), retrieved from the SIMAR-44 database (Puertos del Estado), and validated against actual tide gauge measurements and buoy data (RedMar and RedExt networks). Analyses of total water levels showed a long term increase since 1958, resulting from the increase of mean sea level; conversely, a reduction of the frequency and the intensity of the storm events were deduced from the analysis of meteorological records. Since the impact of the storms on macro- and meso- tidal coast closely depend on the tides, a storm impact index was computed taking into account the storm surge magnitude, the wave heights and time duration during which a predefined threshold was exceeded by the sea level. The results are

  11. Kinetics of ATP- and Na(+)-gradient driven Ca2+ transport in basolateral membranes from gills of freshwater- and seawater-adapted tilapia.

    PubMed

    Verbost, P M; Schoenmakers, T J; Flik, G; Wendelaar Bonga, S E

    1994-01-01

    Plasma membranes of the gills of freshwater- and seawater-adapted tilapia were analyzed for Ca(2+)-ATPase and Na+/Ca2+ exchange activity. The relative importance of ATP-driven and Na(+)-gradient-driven Ca2+ transport in Ca2+ extrusion was evaluated on the basis of kinetic analyses in vitro. The Na+/Ca2+ exchangers in branchial membranes from freshwater or seawater fish displayed similar kinetics. The ATP-driven Ca2+ pump, however, showed a somewhat lower affinity for Ca2+ in membranes isolated from seawater gills than in membranes from freshwater gills; no difference in Vmax was found. The activity of the exchanger was estimated to be 50% of that of the ATP-driven pump at prevailing cytosolic Ca2+ concentrations (10(-7) mol l-1). Opercular ionocyte densities and branchial Na+/K(+)-ATPase content were not significantly different in fish residing in fresh water or sea water. We conclude that the gills of tilapia living for prolonged periods in fresh water or sea water do not differ in the make-up of their basolateral membrane with regard to Ca(2+)-ATPase, Na+/Ca2+ exchange and Na+/K(+)-ATPase activity. Apparently, the densities of these carriers suffice for calcium and sodium homeostasis under these vastly different ambient conditions. PMID:7964377

  12. Ethoxyresorufin-O-deethylase (EROD) induction by TCDD, PeCDF and PCB 126 in bobwhite quail hepatocytes.

    PubMed

    Jones, Stephanie P; Farmahin, Reza; Kennedy, Sean W

    2014-07-01

    World Health Organization (WHO) toxic equivalency factors are used to calculate toxic equivalent (TEQ) concentrations of complex mixtures of dioxin-like compounds (DLCs), such as polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls (PCBs), for mammals, fish and birds. The TEQ concept assumes that all species of a taxa respond with similar sensitivity to individual DLCs, but several reports do not support this assumption for birds. Our laboratory is conducting research to attempt to uncover the fundamental mechanism(s) underlying the reasons why avian species differ in sensitivity to DLCs. The present study determined concentration-dependent effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) and 3,3',4,4',5-pentachlorobiphenyl (PCB 126) on ethoxyresorufin-O-deethylase (EROD) activity in primary cultures of northern bobwhite quail (Colinus virginianus) hepatocytes. Bobwhite quail were studied because (1) this species is used in the laboratory for toxicity testing and (2) the amino acids at all locations within the ligand binding domain (LBD) of aryl hydrocarbon receptor 1 (AHR1) in bobwhite quail and ring necked pheasant (Phasianus colchicus) are identical. Because earlier work indicated the importance of the identity of amino acids at key sites within the AHR1 LBD, we hypothesized that bobwhite quail and ring necked pheasant hepatocytes should have similar sensitivity to EROD induction by DLCs. ECthreshold-based relative sensitivity of the bobwhite quail compared to chicken for TCDD, PeCDF and PCB 126 was 0.11, 0.17 and 0.02, respectively. The rank order of potency was PeCDF > TCDD > PCB 126. The results confirm that bobwhite quail and ring-necked pheasant hepatocytes have similar sensitivity to EROD induction by TCDD, PeCDF and PCB 126. PMID:24619315

  13. Organ-Specific and Size-Dependent Ag Nanoparticle Toxicity in Gills and Intestines of Adult Zebrafish.

    PubMed

    Osborne, Olivia J; Lin, Sijie; Chang, Chong Hyun; Ji, Zhaoxia; Yu, Xuechen; Wang, Xiang; Lin, Shuo; Xia, Tian; Nel, André E

    2015-10-27

    We studied adult zebrafish to determine whether the size of 20 and 110 nm citrate-coated silver nanoparticles (AgC NPs) differentially impact the gills and intestines, known target organs for Ag toxicity in fish. Following exposure for 4 h, 4 days, or 4 days plus a 7 day depuration period, we obtained different toxicokinetic profiles for different particle sizes, as determined by Ag content of the tissues. Ionic AgNO3 served as a positive control. The gills showed a significantly higher Ag content for the 20 nm particles at 4 h and 4 days than the 110 nm particles, while the values were more similar in the intestines. Both particle types were retained in the intestines even after depuration. These toxicokinetics were accompanied by striking size-dependent differences in the ultrastructural features and histopathology in the target organs in response to the particulates. Ag staining of the gills and intestines confirmed prominent Ag deposition in the basolateral membranes for the 20 nm but not for the 110 nm particles. Furthermore, it was possible to link the site of tissue deposition to disruption of the Na(+)/K(+) ion channel, which is also localized to the basolateral membrane. This was confirmed by a reduction in ATPase activity and immunohistochemical detection of the α subunit of this channel in both target organs, with the 20 nm particles causing significantly higher inhibition and disruption than the larger size particles or AgNO3. These results demonstrate the importance of particle size in determining the hazardous impact of AgNPs in the gills and intestines of adult zebrafish. PMID:26327297

  14. On the mechanism of sodium extrusion across the irrigated gill of sea water-adapted rainbow trout (Salmo gairdneri).

    PubMed

    Kirschner, L B; Greenwald, L; Sanders, M

    1974-08-01

    Sodium efflux (J(out) (Na)) across the irrigated trout gill was rapid in sea water (SW), but only about 25 % as large in fresh water (FW). The difference correlated with a change in the potential difference across the gill (TEP). The latter was about +10 mV (blood positive) in SW, but -40 mV in FW. Both flux and electrical data indicated that gills in this fish are permeable to a variety of cations including Na(+), K(+), Mg(2+), choline, and Tris. They are less permeable to anions; P(Na):P(K):P(Cl) was estimated to be 1:10:0.3, and P(Cl) > P(gluconate). The TEP was shown to be a diffusion potential determined by these permeabilities and the extant ionic gradients in SW, FW as well as in other media. J(out) (Na) appeared to be diffusive in all of the experiments undertaken. Exchange diffusion need not be posited, and the question of whether there is an active component remains open. PMID:4846764

  15. Soil aggregation, erodibility, and erosion rates in mountain soils (NW Alps, Italy)

    NASA Astrophysics Data System (ADS)

    Stanchi, S.; Falsone, G.; Bonifacio, E.

    2015-04-01

    Erosion is a relevant soil degradation factor in mountain agrosilvopastoral ecosystems that can be enhanced by the abandonment of agricultural land and pastures left to natural evolution. The on-site and off-site consequences of soil erosion at the catchment and landscape scale are particularly relevant and may affect settlements at the interface with mountain ecosystems. RUSLE (Revised Universal Soil Loss Equation) estimates of soil erosion consider, among others, the soil erodibility factor (K), which depends on properties involved in structure and aggregation. A relationship between soil erodibility and aggregation should therefore be expected. However, erosion may limit the development of soil structure; hence aggregates should not only be related to erodibility but also partially mirror soil erosion rates. The aim of the research was to evaluate the agreement between aggregate stability and erosion-related variables and to discuss the possible reasons for discrepancies in the two kinds of land use considered (forest and pasture). Topsoil horizons were sampled in a mountain catchment under two vegetation covers (pasture vs. forest) and analyzed for total organic carbon, total extractable carbon, pH, and texture. Soil erodibility was computed, RUSLE erosion rate was estimated, and aggregate stability was determined by wet sieving. Aggregation and RUSLE-related parameters for the two vegetation covers were investigated through statistical tests such as ANOVA, correlation, and regression. Soil erodibility was in agreement with the aggregate stability parameters; i.e., the most erodible soils in terms of K values also displayed weaker aggregation. Despite this general observation, when estimating K from aggregate losses the ANOVA conducted on the regression residuals showed land-use-dependent trends (negative average residuals for forest soils, positive for pastures). Therefore, soil aggregation seemed to mirror the actual topsoil conditions better than soil

  16. Lagrangian approach to understanding the origin of the gill-kinematics switch in mayfly nymphs.

    PubMed

    Chabreyrie, R; Balaras, E; Abdelaziz, K; Kiger, K

    2014-12-01

    The mayfly nymph breathes under water through an oscillating array of plate-shaped tracheal gills. As the nymph grows, the kinematics of these gills change abruptly from rowing to flapping. The classical fluid dynamics approach to consider the mayfly nymph as a pumping device fails in giving clear reasons for this switch. In order to shed some light on this switch between the two distinct kinematics, we analyze the problem under a Lagrangian viewpoint. We consider that a good Lagrangian transport that effectively distributes and stirs water and dissolved oxygen between and around the gills is the main goal of the gill motion. Using this Lagrangian approach, we are able to provide possible reasons behind the observed switch from rowing to flapping. More precisely, we conduct a series of in silico mayfly nymph experiments, where body shape, as well as gill shapes, structures, and kinematics are matched to those from in vivo. In this paper, we show both qualitatively and quantitatively how the change of kinematics enables better attraction, confinement, and stirring of water charged of dissolved oxygen inside the gills area. We reveal the attracting barriers to transport, i.e., attracting Lagrangian coherent structures, that form the transport skeleton between and around the gills. In addition, we quantify how well the fluid particles are stirred inside the gills area, which by extension leads us to conclude that it will increase the proneness of molecules of dissolved oxygen to be close enough to the gills for extraction. PMID:25615123

  17. Lagrangian approach to understanding the origin of the gill-kinematics switch in mayfly nymphs

    NASA Astrophysics Data System (ADS)

    Chabreyrie, R.; Balaras, E.; Abdelaziz, K.; Kiger, K.

    2014-12-01

    The mayfly nymph breathes under water through an oscillating array of plate-shaped tracheal gills. As the nymph grows, the kinematics of these gills change abruptly from rowing to flapping. The classical fluid dynamics approach to consider the mayfly nymph as a pumping device fails in giving clear reasons for this switch. In order to shed some light on this switch between the two distinct kinematics, we analyze the problem under a Lagrangian viewpoint. We consider that a good Lagrangian transport that effectively distributes and stirs water and dissolved oxygen between and around the gills is the main goal of the gill motion. Using this Lagrangian approach, we are able to provide possible reasons behind the observed switch from rowing to flapping. More precisely, we conduct a series of in silico mayfly nymph experiments, where body shape, as well as gill shapes, structures, and kinematics are matched to those from in vivo. In this paper, we show both qualitatively and quantitatively how the change of kinematics enables better attraction, confinement, and stirring of water charged of dissolved oxygen inside the gills area. We reveal the attracting barriers to transport, i.e., attracting Lagrangian coherent structures, that form the transport skeleton between and around the gills. In addition, we quantify how well the fluid particles are stirred inside the gills area, which by extension leads us to conclude that it will increase the proneness of molecules of dissolved oxygen to be close enough to the gills for extraction.

  18. Effects of gill abrasion and experimental infection with Tenacibaculum maritimum on the respiratory physiology of Atlantic salmon Salmo salar affected by amoebic gill disease.

    PubMed

    Powell, Mark D; Harris, James O; Carson, Jeremy; Hill, Jonathan V

    2005-02-28

    The effects of gill abrasion and experimental infection with Tenacibaculum maritimum were assessed in Atlantic salmon Salmo salar with underlying amoebic gill disease. The respiratory and acid-base parameters arterial oxygen tension (P(a)O2), arterial whole blood oxygen content (C(a)O2), arterial pH (pHa), haematocrit and haemoglobin concentrations were measured at intervals over a 48 h recovery period following surgical cannulation of the dorsal aorta. Mortality rates over the recovery period were variable, with gill abrasion and inoculation with T. maritimum causing the highest initial mortality rate and unabraded, uninoculated controls showing the lowest overall mortality rate. Fish with abraded gills tended to show reduced P(a)O2 and lower C(a)O2 compared with unabraded fish. Infection with T. maritimum had no effect on P(a)O2 or C(a)O2. All fish showed an initial alkalosis at 24 h post-surgery/inoculation which was more pronounced in fish inoculated with T. maritimum. There were no significant effects of gill abrasion or infection upon the ratio of oxygen specifically bound to haemoglobin or mean cellular haemoglobin concentration. Histologically, 48 h following surgery, abraded gills showed multifocal hyperplastic lesions with pronounced branchial congestion and telangiectasis, and those inoculated with T. maritimum exhibited focal areas of branchial necrosis and erosion associated with filamentous bacterial mats. All fish examined showed signs of amoebic gill disease with multifocal hyperplastic and spongious lesions with parasome-containing amoeba associated with the gill epithelium. The results suggest that respiratory compromise occurred as a consequence of gill abrasion rather than infection with T. maritimum. PMID:15819432

  19. Respiratory medicine and research at McGill University: A historical perspective

    PubMed Central

    Martin, James G; Schwartzman, Kevin

    2015-01-01

    pathological and clinical observations. Dr Margaret Becklake immigrated to Montreal from South Africa in 1957. Her research focused on occupational lung disease. She established the respiratory epidemiology research unit at McGill. She was renowned for her insistence on the importance of a clearly stated, relevant research question and for her clarity and insight. Dr William Thurlbeck, another South African, had developed an interest in emphysema and chronic bronchitis and applied a structure-function approach in collaboration with Peter Macklem and other respirologists. As chief of the Royal Victoria autopsy service, he used pathological specimens to develop a semiquantitative grading system of gross emphysema severity. He promoted the use of morphometry to quantify structural abnormalities. Dr James Hogg studied the functional consequences of pathological processes for lung function during his PhD studies under the joint supervision of Drs Macklem and Thurlbeck. His contributions to understanding the structural basis for chronic obstructive pulmonary disease (COPD) are numerous, reflecting his transdisciplinary knowledge of respiratory pathology and physiology. He trained other outstanding investigators such as Peter Paré Jr, with whom he founded the Pulmonary Research Laboratory in St Paul’s Hospital in Vancouver (British Columbia) in 1977. A signal event in the evolution of respiratory research at McGill was the construction of the Meakins-Christie Laboratories in 1972. These laboratories were directed by Dr Peter Macklem, a trainee of Dr Becklake’s. The research within the laboratory initially focused on respiratory mechanics, gas distribution within the lung and the contribution of airways of different sizes to the overall mechanical behaviour of the lungs. The effects of cigarette smoking on lung dysfunction, mechanisms of possible loss of lung elastic recoil in asthma and control of bronchomotor tone were all additional areas of active investigation. Dr Macklem

  20. Role of soil erodibility in affecting available nitrogen and phosphorus losses under simulated rainfall

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Wu, Binbin; Zhang, Lei; Jiang, Hong; Xu, Zongxue

    2014-06-01

    The loss of available nutrients and the effects of soil erodibility on available nutrients losses were rarely researched. Here, laboratory simulation experiments were conducted to determine the soil erodibility effects on the available nitrogen (AN) and phosphorus (AP) losses. The impacts of rainfall intensity and slope on AN and AP losses were also studied. Two contrasting agricultural soils (Burozems and Cinnamon) that occur throughout the northern erosion region of China were selected. Two rainfall intensities (60 and 120 mm h-1) and two slopes (10% and 20%) were studied. Overall, greater runoff, sediment and available nutrient losses occurred from the Cinnamon soil due to its greater soil erodibility, which was approximately 2.8 times greater than that of the Burozems soil. The influence of runoff on sediment was positively linear. The absolute slope of the regression line between runoff rate and sediment yield rate was suitable as a soil erodibility indicator. Runoff-associated AN and AP losses were mainly controlled by runoff rate, and were weakly affected by soil erodibility (p > 0.05). However, soil erodibility significantly influenced the sediment-associated AN and AP losses (p < 0.01), and a positive logarithmic correlation best described their relationships. Since the runoff-associated AN and AP losses dominated the total AN and AP losses for both soils, soil erodibility also exhibited negligible influence on the total AN and AP losses (p > 0.05). Increasing rainfall intensity and slope generally increased the runoff, sediment, and available nutrient losses for both soils, but had no significant influences on their relationships. Our results provide a better understanding of soil and nutrient loss mechanisms.

  1. Brushing abrasion of eroded dentin after application of sodium fluoride solutions.

    PubMed

    Attin, T; Zirkel, C; Hellwig, E

    1998-01-01

    The aim of the present in vitro study was to evaluate the influence of sodium fluoride solutions on brushing abrasion of eroded dentin. Dentin specimens were prepared from 60 bovine incisors. The specimens were embedded in acrylic resin, ground flat, polished and subsequently covered with tape exposing an area of 1.8 mm x 10.0 mm in the center of the exposed dentin. The samples were alternatingly stored in a demineralizing solution (5 min) and a remineralizing solution (1 min) for 5 times. The erosive soft drink Sprite light(R) served as a demineralizing solution and artificial saliva was used as a remineralizing solution. Prior to storage in artificial saliva 15 specimens were each treated for 1 min with 250 and 2,000 ppm fluoride solution, respectively. Fifteen specimens were treated with distilled water instead of the fluoride solution (= eroded controls). The remaining samples were neither eroded with the soft drink nor fluoridated (= uneroded controls). After each immersion in artificial saliva the specimens were submitted to abrasion in a toothbrushing machine. After 5 demineralization-remineralization brushing cycles the total amount of tooth wear due to erosion and subsequent abrasion was profilometrically evaluated. Statistical analysis revealed the significantly lowest wear in the uneroded controls and the highest amount of abrasion in the eroded controls. Application of the fluoride solutions increased the wear resistance of the eroded dentin specimens, showing significantly better protection by the high-concentration compared to the low-concentration solution. The susceptibility to abrasion of the eroded dentin specimens treated with the high-concentration fluoride solution did not differ significantly from the uneroded dentin samples. It is concluded that application of 2,000 ppm sodium fluoride solutions immediately before toothbrushing significantly reduces abrasion of eroded dentin in vitro. PMID:9701659

  2. PARP1 Is a TRF2-associated Poly(ADP-Ribose)Polymerase and Protects Eroded Telomeres

    SciTech Connect

    Liu, Yie; Wu, Jun; Schreiber, Valerie; Dunlap, John; Dantzer, Francoise; Wang, Yisong

    2006-01-01

    Poly(ADP-ribose)polymerase 1 (PARP1) is well characterized for its role in base excision repair (BER), where it is activated by and binds to DNA breaks and catalyzes the poly(ADP-ribosyl)ation of several substrates involved in DNA damage repair. Here we demonstrate that PARP1 associates with telomere repeat binding factor 2 (TRF2) and is capable of poly(ADP-ribosyl)ation of TRF2, which affects binding of TRF2 to telomeric DNA. Immunostaining of interphase cells or metaphase spreads shows that PARP1 is detected sporadically at normal telomeres, but it appears preferentially at eroded telomeres caused by telomerase deficiency or damaged telomeres induced by DNA-damaging reagents. Although PARP1 is dispensable in the capping of normal telomeres, Parp1 deficiency leads to an increase in chromosome end-to-end fusions or chromosome ends without detectable telomeric DNA in primary murine cells after induction of DNA damage. Our results suggest that upon DNA damage, PARP1 is recruited to damaged telomeres, where it can help protect telomeres against chromosome end-to-end fusions and genomic instability.

  3. PARP1 is a TRF2-associated poly(ADP-ribose) polymerase and protects eroded telomeres

    SciTech Connect

    Gomez, Marla V; Wu, Jun; Wang, Yisong; Liu, Yie

    2006-01-01

    Poly(ADP-ribose)polymerase 1 (PARP1) is well characterized for its role in base excision repair (BER), where it is activated by and binds to DNA breaks and catalyzes the poly(ADP-ribosyl)ation of several substrates involved in DNA damage repair. Here we demonstrate that PARP1 associates with telomere repeat binding factor 2 (TRF2) and is capable of poly(ADP-ribosyl)ation of TRF2, which affects binding of TRF2 to telomeric DNA. Immunostaining of interphase cells or metaphase spreads shows that PARP1 is detected sporadically at normal telomeres, but it appears preferentially at eroded telomeres caused by telomerase deficiency or damaged telomeres induced by DNA-damaging reagents. Although PARP1 is dispensable in the capping of normal telomeres, Parp1 deficiency leads to an increase in chromosome end-to-end fusions or chromosome ends without detectable telomeric DNA in primary murine cells after induction of DNA damage. Our results suggest that upon DNA damage, PARP1 is recruited to damaged telomeres, where it can help protect telomeres against chromosome end-to-end fusions and genomic instability.

  4. Cold acclimation of NaCl secretion in a eurythermic teleost: mitochondrial function and gill remodeling.

    PubMed

    Barnes, Katelyn R; Cozzi, Regina R F; Robertson, George; Marshall, William S

    2014-02-01

    Active chloride secretion, measured as short-circuit current (Isc) in ionocytes of opercular epithelia (OE) in the eurythermic, euryoxic, and euryhaline killifish or mummichog (Fundulus heteroclitus) was studied in cold (5°C) and warm (20°C) acclimated fish to determine if homeoviscous adaptation aided chloride secretion in the cold. Isolated opercular epithelia were cooled from 30°C to 0.2°C for warm and cold acclimated fish; from 30 to 8°C, Isc decreased with Q10=1.68 for warm and Q10=1.56 for cold acclimated tissues. By Arrhenius plots, there is a critical temperature, 8°C, below which aerobic Isc decreased sharply (Q10=6.90 for warm and 4.23 for cold acclimated tissues), suggesting a shift in mitochondrial efficiency of oxidative phosphorylation. In anaerobic conditions (0.5mM NaCN; N2 saturation), chloride transport continued at a lower rate, and Isc decrease with cooling below 8°C was less pronounced (Q10=2.95 for warm and 3.08 for cold), suggesting a shift in transporter function in plasma membrane. Under anaerobic conditions, NaCl secretion at 20°C was reversibly inhibited by hypotonic shock, indicating normal regulation of transport. Chloride secretion in warm-acclimated fish was supported mostly (75% at 20°C) by aerobic metabolism, whereas that for cold-acclimated fish was lower (55% at 20°C), suggesting a greater reliance on anaerobic metabolism in the cold. Once acclimated to cold, ionocytes may be temporarily incapable of increasing their aerobic ATP supply, even when warmed to 30°C. In cold acclimated fish there was increased polyunsaturated fatty acid composition of gill epithelium (consistent with homeoviscous adaptation) and gill remodeling, wherein epithelial cells filled the interlamellar space (interlamellar cell mass, ILCM) by as much as 70%, thus increasing diffusion distance against passive ion gain. Most ionocytes in these thickened epithelial masses became taller, still connecting basal lamina with the environment, consistent

  5. Seabed erodibility variations on the Louisiana continental shelf before and after the 2011 Mississippi River flood

    NASA Astrophysics Data System (ADS)

    Xu, K.; Corbett, D. R.; Walsh, J. P.; Young, D.; Briggs, K. B.; Cartwright, G. M.; Friedrichs, C. T.; Harris, C. K.; Mickey, R. C.; Mitra, S.

    2014-08-01

    Erodibility is critical to the sediment resuspension process but has not been measured systematically in large river-dominated muddy continental shelves before. During early summer of 2011, the Mississippi River experienced a major flood event. This flood provided a unique opportunity to examine how shelf seabed erodibility responded to a large river flood, and the ultimate fate of flood deposition is important to geological and biogeochemical processes (e.g., stratal formation, carbon sequestration). A total of 106 sediment cores were collected on the Louisiana shelf during five cruises in 2010 and 2011, and a new dataset was used to evaluate the response of the seabed to the recent conditions. The localized flood deposit was mainly within tens of kilometers of river sources, and little sediment accumulated on the middle Louisiana shelf. Seabed erodibility was measured using a dual-core Gust Erosion Microcosm System. The erodibility of sediment collected in April 2011 exceeded that for August 2010 and August 2011. The springtime increase in erodibility seemed to be related to the recent presence of energetic waves that mobilized the seabed. Erodibility was highest on the inner shelf southwest of Atchafalaya Bay, intermediate on the middle shelf, lowest in the Mississippi Canyon, and highly variable on the Mississippi subaqueous delta. These spatial patterns were influenced by proximity to river sources, flood-deposit thicknesses, intensity of wave-driven bed stresses, and bioturbation. The flood-deposit thickness itself, however, was not sufficient to explain all the spatial variations of erodibility after the peak of the Mississippi flood. Comparing values to published data, the depth-varying erodibility on the Louisiana shelf was close to the "low erodibility" level for the York River of Virginia, and similar to the data collected from Baltimore Harbor in Maryland and the main stem of upper Chesapeake Bay. Our findings promote understanding of the resuspension

  6. Prediction of erodibility in Oxisols using iron oxides, soil color and diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Arantes Camargo, Livia; Marques, José, Jr.

    2015-04-01

    The prediction of erodibility using indirect methods such as diffuse reflectance spectroscopy could facilitate the characterization of the spatial variability in large areas and optimize implementation of conservation practices. The aim of this study was to evaluate the prediction of interrill erodibility (Ki) and rill erodibility (Kr) by means of iron oxides content and soil color using multiple linear regression and diffuse reflectance spectroscopy (DRS) using regression analysis by least squares partial (PLSR). The soils were collected from three geomorphic surfaces and analyzed for chemical, physical and mineralogical properties, plus scanned in the spectral range from the visible and infrared. Maps of spatial distribution of Ki and Kr were built with the values calculated by the calibrated models that obtained the best accuracy using geostatistics. Interrill-rill erodibility presented negative correlation with iron extracted by dithionite-citrate-bicarbonate, hematite, and chroma, confirming the influence of iron oxides in soil structural stability. Hematite and hue were the attributes that most contributed in calibration models by multiple linear regression for the prediction of Ki (R2 = 0.55) and Kr (R2 = 0.53). The diffuse reflectance spectroscopy via PLSR allowed to predict Interrill-rill erodibility with high accuracy (R2adj = 0.76, 0.81 respectively and RPD> 2.0) in the range of the visible spectrum (380-800 nm) and the characterization of the spatial variability of these attributes by geostatistics.

  7. Hypothetical Reentry Thermostructural Performance of Space Shuttle Orbiter With Missing or Eroded Thermal Protection Tiles

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Gong, Leslie; Quinn, Robert D.

    2004-01-01

    This report deals with hypothetical reentry thermostructural performance of the Space Shuttle orbiter with missing or eroded thermal protection system (TPS) tiles. The original STS-5 heating (normal transition at 1100 sec) and the modified STS-5 heating (premature transition at 800 sec) were used as reentry heat inputs. The TPS missing or eroded site is assumed to be located at the center or corner (spar-rib juncture) of the lower surface of wing midspan bay 3. For cases of missing TPS tiles, under the original STS-5 heating, the orbiter can afford to lose only one TPS tile at the center or two TPS tiles at the corner (spar-rib juncture) of the lower surface of wing midspan bay 3. Under modified STS-5 heating, the orbiter cannot afford to lose even one TPS tile at the center or at the corner of the lower surface of wing midspan bay 3. For cases of eroded TPS tiles, the aluminum skin temperature rises relatively slowly with the decreasing thickness of the eroded central or corner TPS tile until most of the TPS tile is eroded away, and then increases exponentially toward the missing tile case.

  8. Sex-response differences of immunological and histopathological biomarkers in gill of Prochilodus argenteus from a polluted river in southeast Brazil.

    PubMed

    Procópio, Marcela Santos; Ribeiro, Heder José; Pereira, Luciano Almeida; Oliveira Lopes, Gabriel Augusto; Castro, Antônio Carlos Santana; Rizzo, Elizete; Sato, Yoshimi; Russo, Remo Castro; Corrêa, José Dias

    2014-07-01

    The fish gill is in direct and standing contact with the immediate external environment and, therefore, is highly vulnerable to aquatic pollutants. In this study, Prochilodus argenteus were caught at two different points in São Francisco river. The first point is located near Três Marias dam, while the second is placed downstream the Abaeté river. Chemical approaches showed the presence of metals contamination in the first point. Thus, the main goal of this study was to investigate the possible toxic effects of these contaminants and the likely use of biomarkers on fish gills. Biometric data of length and weight of fish were obtained in order to calculate the condition factor as an organismal biomarker. The histological changes in gills and alterations in mucous and rodlet cells occurrence were detected microscopically and evaluated with quantitative analyses. Myeloperoxidase (MPO) and Eosinophil Peroxidase (EPO) were also assessed in fish gill. The analysis of the water and sediment samples revealed the presence of metals at the two points. As and Cd were detected at higher concentrations at point 1. The presence of lamellar cell hyperplasia, lamellar fusion, lamellar edema and inflammatory foci varied according to the point. Additionally, mucous and rodlet cells and MPO and EPO activities showed variability according to the environmental conditions. Furthermore, with exception of lamellar hyperplasia and eosinophil peroxidase activity, all others parameters showed sex-variation responses. At the first point, male fish showed a chronical inflammation in gills due to the lowest activity of MPO and EPO, as well as low occurrence of inflammatory foci and glycoprotein secretion by mucous cells, while female fish presented an opposite pattern of response to the same environmental conditions. Therefore, we suggest the use of such biomarkers in future monitoring of aquatic systems, taking into account the sex-variation responses. PMID:24795082

  9. Ethoxyresorufin-O-deethylase (EROD) induction in rainbow trout exposed to diluted oil sand wastewater

    SciTech Connect

    Verbeek, A.; Mackay, W.; Birkholz, D.

    1995-12-31

    Toxic industrial wastewaters, such as those from oil sands extraction, must be assessed for their potential sublethal effects before they can be safely disposed in the environment. The induction of ethoxyresorufin-O-deethylase activity was assessed as a potential bioindicator of sublethal stress in rainbow trout exposed to sublethal concentrations of oil sands tailings water. The mixed-function oxygenase system in rainbow trout responded rapidly following a definable concentration-response relationship; however, it proved to be a relatively insensitive indicator of sublethal exposure to oil sands tailings water. Increased activity and maximal induction, as a result of exposure to 0.3 and 0.6 times the LC{sub 50} (Toxic Units), occurred rapidly within 24 hours of exposure. The linearity of the relationship between the concentration of oil sands tailings pond water and ethoxyresorufin-O-deethylase activity, expressed by the following regression equation, In EROD = 3.68 (conc.) + 3.20, had an r{sup 2} value of 0.593. Maximal induction required 0.4--0.8 Toxic Units. The absolute level of maximal induction was only one-fifth to one-sixth of the potential induction as found in response to the positive control, 0.5 mg/kg {beta}-naphthoflavone (i.p.). The authors also present data that suggests that the different levels of induction observed in trout exposed to tailings pond water vs those injected with 0.5 mg/kg {beta}-naphthoflavone (i.p.) may be indicative of two different P450 isoforms, the CYP4Al isoform responding to the organic acidic surfactants in oil sands tailings pond water and the CYP1A1 isoform, the isoform generally associated with most xenobiotic transformation in fish, responding to {beta}-naphthoflavone.

  10. Toxicity of dispersant application: Biomarkers responses in gills of juvenile golden grey mullet (Liza aurata).

    PubMed

    Milinkovitch, Thomas; Godefroy, Joachim; Théron, Michaël; Thomas-Guyon, Hélène

    2011-10-01

    Dispersant use in nearshore areas is likely to increase the exposure of aquatic organisms to petroleum. To measure the toxicity of this controversial response technique, golden grey mullets (Liza aurata) were exposed to mechanically dispersed oil, chemically dispersed oil, dispersant alone in seawater, water-soluble fraction of oil and to seawater as a control treatment. Several biomarkers were assessed in the gills (enzymatic antioxidant activities, glutathione content, lipid peroxidation) and in the gallbladder (polycylic aromatic hydrocarbons metabolites). The significant differences between chemically dispersed oil and water soluble fraction of oil highlight the environmental risk to disperse an oil slick when containment and recovery can be conducted. The lack of significance between chemically and mechanically dispersed oil suggests that dispersant application is no more toxic than the natural dispersion of the oil slick. The results of this study are of interest in order to establish dispersant use policies in nearshore areas. PMID:21592637

  11. ULTRASTRUCTURAL STUDY OF LESIONS IN GILLS OF A MARINE SHRIMP EXPOSED TO CADMIUM

    EPA Science Inventory

    Pathologic black gills of pink shrimp, Penaeus duorarum, exposed to 763 micrograms/l of cadmium chloride for 15 days were studied with transmission electron microscopy and were compared with normal gills of control pink shrimp. Local as well as extensive areas of cell death and n...

  12. Training Researchers in Cultural Psychiatry: The McGill-CIHR Strategic Training Program

    ERIC Educational Resources Information Center

    Kirmayer, Laurence J.; Rousseau, Cecile; Corin, Ellen; Groleau, Danielle

    2008-01-01

    Objectives: The authors aim to summarize the pedagogical approaches and curriculum used in the training of researchers in cultural psychiatry at the Division of Social and Transcultural Psychiatry at McGill University. Method: We reviewed available published and unpublished reports on the history and development of the McGill cultural psychiatry…

  13. Urotensin II and its receptor in the killifish gill: regulators of NaCl extrusion.

    PubMed

    Evans, David H; Hyndman, Kelly A; Cornwell, Emily; Buchanan, Patrick

    2011-12-01

    The peptide urotensin II (UII) and its receptor (UT) mediate cardiovascular and renal effects in both mammals and fishes. In both groups, vasopressor and diuretic responses predominate, although, in mammals, some secondary vasodilatation is found, mediated by secondary release of nitric oxide or prostacyclin. In fishes, gill extrusion of NaCl is inhibited by UII, but a single study has determined that UT is expressed in gill vasculature, not on the epithelium that mediates the transport. To begin to clarify the pathways involved in UII inhibition of gill transport, we have cloned the cDNA encoding UII and UT from the euryhaline killifish (Fundulus heteroclitus L.) gill and spinal cord, quantified UT mRNA expression in various tissues and measured relative expression in gill tissue from fish acclimated to seawater (SW) vs fresh water (FW). We have also localized UT in the gill epithelium, and measured the effect of UII on ion transport across the opercular epithelium. We found that both UII and UT are synthesized in the gill of F. heteroclitus and that gill UT mRNA levels are ~80% higher in SW- vs FW-acclimated individuals. In addition, UII inhibits NaCl transport across the opercular epithelium in a concentration-dependent manner, and this inhibition is at least partially mediated by both nitric oxide and a prostanoid. PMID:22071190

  14. ANALYTICAL METHOD FOR THE DETERMINATION OF PHENYLGLUCURONIDE IN RAINBOW TROUT GILL WATER

    EPA Science Inventory

    Phenylglucuronide (PG), a primary phase II metabolite of phenol, can be excreted by fish through urine and feces, similar to mammals. In addition, it may also be possible to eliminate it through a fish's gills. In order to assess the significance of gill water elimination, analyt...

  15. Determination of the CYP1A-inducing potential of single substances, mixtures and extracts of samples in the micro-EROD assay with H4IIE cells.

    PubMed

    Schiwy, Andreas; Brinkmann, Markus; Thiem, Ines; Guder, Gabriele; Winkens, Kerstin; Eichbaum, Kathrin; Nüßer, Leonie; Thalmann, Beat; Buchinger, Sebastian; Reifferscheid, Georg; Seiler, Thomas-Benjamin; Thoms, Brigitte; Hollert, Henner

    2015-11-01

    This protocol describes a quantitative and robust 96-well-plate-reader-based assay for the measurement of ethoxyresorufin-O-deethylase (EROD) activity using the rat hepatoma cell line H4IIE. The assay can be used to determine the cytochrome P450 subfamily 1A (CYP1A)-inducing potential of single substances, as well as of mixtures and extracts of samples. It is based on the aryl hydrocarbon receptor (AhR)-mediated induction of cytochrome P450 enzymes (subfamily 1A) in cells after exposure to dioxins and dioxin-like compounds. One enzymatic reaction catalyzed by CYP1A is the deethylation of the exogenous substrate 7-ethoxyresorufin to the fluorescent product resorufin, which is measured as EROD activity in the assay. The CYP1A-inducing potential of a sample can be reliably quantified by comparing the EROD activity with the concentration-response curve of the standard substance 2,3,7,8-tetrachlorodibenzo-p-dioxin, which can be detected at concentrations down to the picogram per liter range. A researcher familiar with the procedure can process up to 160 samples with four wells each within 3 d. The series described uses four plates with three concentrations per sample, which can be easily scaled to accommodate different sample sizes. PMID:26448361

  16. Implementation of the century ecosystem model for an eroding hillslope in Mississippi

    USGS Publications Warehouse

    Sharpe, Jodie; Harden, Jennifer W.; Dabney, Seth M.; Ojima, Dennis; Parton, William

    1998-01-01

    The objective of this study was to parameterize and implement the Century ecosystem model for an eroding, cultivated site near Senatobia, in Panola County, Mississippi, in order to understand the loss and replacement of soil organic carbon on an eroding cropland. The sites chosen for this study are located on highly eroded loess soils where USDA has conducted studies on rates of soil erosion. We used USDA sediment data from the study site and historical erosion estimates from the nearby area as model input for soil loss; in addition, inputs for parametization include particle-size data, climate data, and rainfall/runoff data that were collected and reported in companion papers. A cropping scenario was implemented to simulate a research site at the USDA watershed 2 at the Nelson Farm. Model output was compiled for comparison with data collected and reported in companion reports; interpretive comparisons are reported in Harden et al, in press.

  17. Insights into Spatial Sulfur Variation within the Modified Gill-Chamber of the Epibiont-Colonized Hydrothermal Vent Shrimp, Rimicaris exoculata

    NASA Astrophysics Data System (ADS)

    Rempfert, K. R.; Sievert, S. M.; Hansel, C. M.; Webb, S. M.; Thomas, F.

    2013-12-01

    Rimicaris exoculata dominates the megafaunal biomass at numerous Mid-Atlantic hydrothermal vents. Within the gill chamber of the shrimp exists a rich epibiotic community. These shrimp swarm around active black smoker chimneys at the Snake Pit vent site on the Mid-Atlantic Ridge, and have been hypothesized to utilize the mixing zone between ambient seawater and hydrothermal fluid to supply these epibionts with a redox environment suitable for the promotion of chemoautotrophic growth. Investigation of the oxidation state, distribution, and concentration of sulfur of different compartments within the shrimp's gill chamber was conducted using synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy. Principle component analysis of point XANES spectra yielded four reference components indentified as elemental sulfur, sulfate, monosulfide (likely iron sulfide), and an organosulfur thiol compound. Energy specific micro-XRF mapping of these reference components in both the modified mouthparts and inner lining of the carapace enclosing the gill chamber displayed spatial heterogeneity in sulfur oxidation state and coordination. Sulfate, organosulfur thiol compounds, and phosphate tended to correlate with chitin structural features, while elemental sulfur was concentrated in areas where epibionts were observed. DNA extraction and sequencing from epibiont populations within each of the modified mouthparts and carapace was conducted to provide insight into the community structure at each of these distinct areas of the gill chamber. Here we demonstrate the complexity of sulfur speciation and mineralization in association with the host epibiont community composition.

  18. Characterization of copper transport in gill cells of a mangrove crab Ucides cordatus.

    PubMed

    Sá, M G; Zanotto, F P

    2013-11-15

    The branchial epithelium of crustaceans is exposed to the environment and is the first site affected by metal pollution. The aim of this work was to characterize copper (Cu) transport using a fluorescent dye, Phen Green, in gill cells of a hypo-hyper-regulator mangrove crab Ucides cordatus. The results showed that added extracellular CuCl2 (0, 0.025, 0.150, 0.275, 0.550 and 1.110 μM) showed typical Michaelis-Menten transport for Cu in anterior and posterior gill cells (Vmax for anterior and posterior gills: 0.41 ± 0.12 and 1.76 ± 0.27 intracellular Cu in μM × 22.10(4)cells(-1)× 300 s(-1) respectively and Km values: 0.44 ± 0.04 and 0.32 ± 0.13 μM, respectively). Intracellular Cu was significantly higher for posterior gill cells compared to anterior gill cells, suggesting differential accumulation for each gill type. Extracellular Ca at 20mM decreased cellular Cu transport for both anterior and posterior gill cells. Nifedipine and verapamil, calcium channel inhibitors from plasma membrane, decreased Cu transport and affected Km for both gills. These results could be due to a competition between Cu and Ca. Amiloride, a Na/Ca exchanger inhibitor, as well as bafilomycin, a proton pump inhibitor, caused a decrease of intracellular Cu compared to control. Ouabain and KB-R 7943, acting on Na homeostasis, similarly decreased intracellular Cu in both gill cells. Besides that, gill cells exposed to ATP and Cu simultaneously, showed an increase in intracellular copper, which was inhibited by vanadate, an inhibitor of P-type ATPase. These results suggest either the presence of a Cu-ATPase in crab gill cells, responsible for Cu influx, or the effect of a change in electrochemical membrane potential that could also drive Cu to the gill cell interior. Caffeine increased intracellular Cu, suggesting that intracellular Ca could be affecting Cu uptake. Overall the results show that copper uptake in gill cells of crabs is regulated by intracellular Ca, Ca channels and by Na

  19. Gill (Na+ +K+)-ATPase involvement and regulation during salmonid adaptation to salt water.

    PubMed

    Borgatti, A R; Pagliarani, A; Ventrella, V

    1992-08-01

    1. The involvement of gill (Na+ +K+)-ATPase in salmonid adaptation to salt water (SW) is discussed. 2. Gill (Na+ +K+)-ATPase increase during SW adaptation is mainly related to the increased number and complexity of chloride cells deputed to salt extrusion. 3. The temporal relationships between serum peaks of thyroid hormones, cortisol, growth hormone, prolactin and gill (Na+ +K+)-ATPase rise during salmonid smoltification, suggest a hormonal involvement in the enzyme stimulation and thus in the acquirement of SW tolerance. 4. Literature on gill (Na+ +K+)-ATPase response to hormonal treatment is reviewed. The effects produced on gill (Na+ +K+)-ATPase and chloride cells by exogenous hormones point out a complex inter-relationship between the hormones considered. The mechanisms involved in hormonal regulation of the enzyme remain a matter of debate. PMID:1355028

  20. Using stable isotopes to determine sources of eroded carbon in low-order Sierra Nevada catchments

    NASA Astrophysics Data System (ADS)

    McCorkle, E. P.; Berhe, A.; Hunsaker, C. T.; Fogel, M. L.; Hart, S. C.

    2013-12-01

    Recent studies have shown that soil erosion can induce a terrestrial sink for atmospheric carbon dioxide and impose important controls on biogeochemical cycling of other essential elements. However, little information is available on the source of C eroded from different watersheds (i.e., whether most of the eroded material is comprised of litter, soil minerals from topsoil, vs. deep C eroded due to fresh channelization or scouring of stream banks). In order to identify sources of eroded carbon, we compared the C to N ratios and 13C, and 15N stable isotope concentrations of potential source materials to sediments collected in basins at the outlet of low order catchments in the western slopes of the Sierra Nevada. Potential source materials (i.e., surficial organic and mineral soil and stream bank sediments) from three landform positions (crest, back slope, toe slope) were sampled from low- and high-elevation catchments within the Kings River Experimental Watershed. The potential source materials were compared with materials collected from sediment basins at the outlet of the sampled catchments. Preliminary results indicate that the different landform positions have similar concentrations of 13C and 15N, but the stable isotope concentrations of sediments reflect a combination of sources. Further analysis will delineate which pool of carbon is the main contributor to the sediments. Determining the source of the eroded carbon in these catchments is critical for assessing the fate of the eroded C after it is laterally distributed by soil erosion to downslope depositional landforms within the same catchment, or exported out of these catchments.

  1. Mapping Eroded Areas on Mountain Grassland with Terrestrial Photogrammetry and Object-Based Image Analysis

    NASA Astrophysics Data System (ADS)

    Mayr, Andreas; Rutzinger, Martin; Bremer, Magnus; Geitner, Clemens

    2016-06-01

    In the Alps as well as in other mountain regions steep grassland is frequently affected by shallow erosion. Often small landslides or snow movements displace the vegetation together with soil and/or unconsolidated material. This results in bare earth surface patches within the grass covered slope. Close-range and remote sensing techniques are promising for both mapping and monitoring these eroded areas. This is essential for a better geomorphological process understanding, to assess past and recent developments, and to plan mitigation measures. Recent developments in image matching techniques make it feasible to produce high resolution orthophotos and digital elevation models from terrestrial oblique images. In this paper we propose to delineate the boundary of eroded areas for selected scenes of a study area, using close-range photogrammetric data. Striving for an efficient, objective and reproducible workflow for this task, we developed an approach for automated classification of the scenes into the classes grass and eroded. We propose an object-based image analysis (OBIA) workflow which consists of image segmentation and automated threshold selection for classification using the Excess Green Vegetation Index (ExG). The automated workflow is tested with ten different scenes. Compared to a manual classification, grass and eroded areas are classified with an overall accuracy between 90.7% and 95.5%, depending on the scene. The methods proved to be insensitive to differences in illumination of the scenes and greenness of the grass. The proposed workflow reduces user interaction and is transferable to other study areas. We conclude that close-range photogrammetry is a valuable low-cost tool for mapping this type of eroded areas in the field with a high level of detail and quality. In future, the output will be used as ground truth for an area-wide mapping of eroded areas in coarser resolution aerial orthophotos acquired at the same time.

  2. The absence of ion-regulatory suppression in the gills of the aquatic air-breathing fish Trichogaster lalius during oxygen stress.

    PubMed

    Huang, Chun-Yen; Lin, Hsueh-Hsi; Lin, Cheng-Huang; Lin, Hui-Chen

    2015-01-01

    The strategy for most teleost to survive in hypoxic or anoxic conditions is to conserve energy expenditure, which can be achieved by suppressing energy-consuming activities such as ion regulation. However, an air-breathing fish can cope with hypoxic stress using a similar adjustment or by enhancing gas exchange ability, both behaviorally and physiologically. This study examined Trichogaster lalius, an air-breathing fish without apparent gill modification, for their gill ion-regulatory abilities and glycogen utilization under a hypoxic treatment. We recorded air-breathing frequency, branchial morphology, and the expression of ion-regulatory proteins (Na(+)/K(+)-ATPase and vacuolar-type H(+)-ATPase) in the 1(st) and 4(th) gills and labyrinth organ (LO), and the expression of glycogen utilization (GP, glycogen phosphorylase protein expression and glycogen content) and other protein responses (catalase, CAT; carbonic anhydrase II, CAII; heat shock protein 70, HSP70; hypoxia-inducible factor-1α, HIF-1α; proliferating cell nuclear antigen, PCNA; superoxidase dismutase, SOD) in the gills of T. lalius after 3 days in hypoxic and restricted conditions. No morphological modification of the 1(st) and 4(th) gills was observed. The air-breathing behavior of the fish and CAII protein expression both increased under hypoxia. Ion-regulatory abilities were not suppressed in the hypoxic or restricted groups, but glycogen utilization was enhanced within the groups. The expression of HIF-1α, HSP70 and PCNA did not vary among the treatments. Regarding the antioxidant system, decreased CAT enzyme activity was observed among the groups. In conclusion, during hypoxic stress, T. lalius did not significantly reduce energy consumption but enhanced gas exchange ability and glycogen expenditure. PMID:25194989

  3. Na+/K+/2Cl- cotransporter and CFTR gill expression after seawater transfer in smolts (0+) of different Atlantic salmon (Salmo salar) families

    USGS Publications Warehouse

    Mackie, P.M.; Gharbi, K.; Ballantyne, J.S.; McCormick, S.D.; Wright, P.A.

    2007-01-01

    Smoltification involves morphological and physiological changes in the gills that prepare anadromous salmonids to osmoregulate efficiently in seawater. In a previous study, we found that different families of Atlantic salmon (Salmo salar) smolts vary in their ability to osmoregulate when abruptly transferred to cold seawater and that these differences are correlated with gill Na+/K+ ATPase activity. Here we extend these findings to test whether other key transport proteins, namely Na+/K+/2Cl- contransporter (NKCC) and the Cl- channel or cystic fibrosis transmembrane conductance regulator (CFTR), play a significant role in osmoregulatory differences between families. To facilitate molecular analysis of NKCC, we first isolated a gill cDNA containing the complete coding region (1147 aa) of an isoform previously reported as a partial sequence. Phylogenetic analysis showed that this isoform is most closely related to isoforms of the NKCC1a subfamily found in European eel and Mozambique tilapia. In a second step, we quantified NKCC protein abundance as well as mRNA expression levels for NKCC1a and two CFTR isoforms (CFTRI and CFTRII) in 0+ smolts from three families prior to and following seawater transfer. The family with the lowest salinity tolerance also showed significant increases in gill NKCC1a mRNA after seawater transfer. Taken together with our previous study, these data indicate that family differences in expression of transport proteins are in part related to salinity tolerance, although the best indicator of osmoregulatory performance between families may be gill Na+/K+ ATPase activity and CFTR I mRNA levels, rather than Na+/K+ ATPase and NKCC1a mRNA levels or NKCC protein abundance. ?? 2007 Elsevier B.V. All rights reserved.

  4. Erodibility of arable soils in Georgia during the period of storm runoff

    NASA Astrophysics Data System (ADS)

    Gogichaishvili, G. P.

    2012-02-01

    The erodibility of arable soils in Georgia varies from 1.0 to 2.9 t/ha per unit of the rainfall erosivity index. The well-structured brown forest and yellow-brown soils with a high humus content are the most resistant to erosion. The soils in the dry areas of Georgia (gray-cinnamon and cinnamon soils) are the most susceptible to erosion. The first map of the soil erodibility was composed that illustrates the spatial distribution pattern of this parameter in the Georgia territory.

  5. Eroders on a Plane with Three States at a Point. Part I: Deterministic

    NASA Astrophysics Data System (ADS)

    de Santana, L. H.; Ramos, A. D.; Toom, A.

    2015-06-01

    Imagine a huge (in theory, infinite) space, whose elements are called components. We say that we have a configuration, if for every component we have specified its state. All components have one and the same finite set of possible states and one of the elements of is called zero. If all the components of a configuration are zeros, we call it "all zeros". We are especially interested in those configurations, in which only a bounded set of components are in a state different from zero; such a configuration is called an island. Our time is discrete and we may imagine that, due to the forces of nature, at every time step the whole configuration (landscape) is subject to a deterministic uniform local rule such that non-zero components may appear only in the vicinity of already existing non-zero components (like in percolation or contact processes). We say that an operator erodes an island if there is a natural such that "all zeros", that is iterative applications of turn into "all zeros". We call an eroder if it erodes all islands. We look for an algorithm which decides for any whether it is an eroder or not and does it make islands grow or not. In general this problem is algorithmically unsolvable, so we need to restrict our scope; in addition to the afore-mentioned conditions we assume that is monotonic. Studying such processes one has to decide whether time and space are discrete or continuous and in this study we choose discrete time and continuous space just because this case is underrepresented in the literature. But especially important is the set of possible states of every single component. Years ago one of us (A. Toom) presented a rule to decide whether is an eroder for the case when every component has only two possible states. A. Toom also showed that if is an eroder, then it erodes any island in time, which is linear in the diameter of the island. In this work every component has three possible states. It turned out that the difference between two and three

  6. Environmental and developmental effects on external gill loss in the red-eyed tree frog, Agalychnis callidryas.

    PubMed

    Warkentin, K M

    2000-01-01

    I examined the effects of development, hatching, and oxygen availability on external gill loss in red-eyed tree frogs, Agalychnis callidryas. Under natural conditions, the arboreal embryos maintained large external gills until hatching, which occurred from 5-8 d after oviposition. At hatching, when tadpoles entered the water, external gills began to regress. In older hatchlings this process was extremely rapid. Gill circulation was lost on average within 16 min and sometimes within 5 min. Gills often regressed completely in under 2 h. Younger hatchlings reduced gill circulation, shortened and adducted their gills, then resumed normal circulation for some time after hatching; half had completely lost external gills within 24 h. Experimentally increasing the area of egg surface exposed to the air induced loss of external gills in unhatched embryos. Older hatchlings in hypoxic water without access to air maintained their external gills. This suggests that loss of external gills is a response to increased oxygen availability, rather than a response to hatching per se. Extended maintenance of external gills by large, late-hatching embryos may facilitate continued rapid development in closely packed eggs. PMID:11073790

  7. Gill cell culture systems as models for aquatic environmental monitoring.

    PubMed

    Bury, Nic R; Schnell, Sabine; Hogstrand, Christer

    2014-03-01

    A vast number of chemicals require environmental safety assessments for market authorisation. To ensure acceptable water quality, effluents and natural waters are monitored for their potential harmful effects. Tests for market authorisation and environmental monitoring usually involve the use of large numbers of organisms and, for ethical, cost and logistic reasons, there is a drive to develop alternative methods that can predict toxicity to fish without the need to expose any animals. There is therefore a great interest in the potential to use cultured fish cells in chemical toxicity testing. This review summarises the advances made in the area and focuses in particular on a system of cultured fish gill cells grown into an epithelium that permits direct treatment with water samples. PMID:24574380

  8. Analysis of a 16-inch globe valve with eroded walls

    SciTech Connect

    Nitzel, M.E.

    1992-01-01

    During the course of inspection activities at a commercial nuclear power plant varying degrees of wall tinning were observed in several 16-inch globe valves. The wall thinning was observed at several locations on the bridge and bonnet areas of the valves and was thought to be the result of erosion of the wall material. these valves were routinely subjected to leak rate tests as part of the normal inspection and maintenance activities. Erosion of the valve plug seat sufficient to allow leakage would normally be detected by the leak rate testing. However, the question was raised whether severe erosion in the bridge structure would create the potential for a structural failure that would prevent normal closing and seating of the valve. An analytical assessment or scoping analysis'' of one of the valves was undertaken to assess the potential for stresses exceeding yield and to indicate whether a more extensive analysis of the valve would be desirable. a linear-elastic finite element model including the valve body, bonnet region, seat ring, and inlet and outlet bridge structures was developed. The model was subjected to a combination of internal pressure, valve plug seat force, and piping end moments. The results of the analysis indicate that even with erosion more severe than that observed in the actual valves, stress values did not approach yield. From these results it was concluded that yielding of the valve would not be anticipated with the observed erosion levels and that operability of the valves would not be impaired.

  9. Analysis of a 16-inch globe valve with eroded walls

    SciTech Connect

    Nitzel, M.E.

    1992-08-01

    During the course of inspection activities at a commercial nuclear power plant varying degrees of wall tinning were observed in several 16-inch globe valves. The wall thinning was observed at several locations on the bridge and bonnet areas of the valves and was thought to be the result of erosion of the wall material. these valves were routinely subjected to leak rate tests as part of the normal inspection and maintenance activities. Erosion of the valve plug seat sufficient to allow leakage would normally be detected by the leak rate testing. However, the question was raised whether severe erosion in the bridge structure would create the potential for a structural failure that would prevent normal closing and seating of the valve. An analytical assessment or ``scoping analysis`` of one of the valves was undertaken to assess the potential for stresses exceeding yield and to indicate whether a more extensive analysis of the valve would be desirable. a linear-elastic finite element model including the valve body, bonnet region, seat ring, and inlet and outlet bridge structures was developed. The model was subjected to a combination of internal pressure, valve plug seat force, and piping end moments. The results of the analysis indicate that even with erosion more severe than that observed in the actual valves, stress values did not approach yield. From these results it was concluded that yielding of the valve would not be anticipated with the observed erosion levels and that operability of the valves would not be impaired.

  10. Gene expression and cellular localization of ROMKs in the gills and kidney of Mozambique tilapia acclimated to fresh water with high potassium concentration.

    PubMed

    Furukawa, Fumiya; Watanabe, Soichi; Kakumura, Keigo; Hiroi, Junya; Kaneko, Toyoji

    2014-12-01

    Regulation of plasma K(+) levels in narrow ranges is vital to vertebrate animals. Since seawater (SW) teleosts are loaded with excess K(+), they constantly excrete K(+) from the gills. However, the K(+) regulatory mechanisms in freshwater (FW)-acclimated teleosts are still unclear. We aimed to identify the possible K(+) regulatory mechanisms in the gills and kidney, the two major osmoregulatory organs, of FW-acclimated Mozambique tilapia (Oreochromis mossambicus). As a potential molecular candidate for renal K(+) handling, a putative renal outer medullary K(+) channel (ROMK) was cloned from the tilapia kidney and tentatively named "ROMKb"; another ROMK previously cloned from the tilapia gills was thus renamed "ROMKa". The fish were acclimated to control FW or to high-K(+) (H-K) FW for 1 wk, and we assessed physiological responses of tilapia to H-K treatment. As a result, urinary K(+) levels were slightly higher in H-K fish, implying a role of the kidney in K(+) excretion. However, the mRNA expression levels of both ROMKa and ROMKb were very low in the kidney, while that of K(+)/Cl(-) cotransporter 1 (KCC1) was robust. In the gills, ROMKa mRNA was markedly upregulated in H-K fish. Immunofluorescence staining showed that branchial ROMKa was expressed at the apical membrane of type I and type III ionocytes, and the ROMKa immunosignals were more intense in H-K fish than in control fish. The present study suggests that branchial ROMKa takes a central role for K(+) regulation in FW conditions and that K(+) excretion via the gills is activated irrespective of environmental salinity. PMID:25298512

  11. A mechanism for branchial acid excretion in marine fish: identification of multiple Na+/H+ antiporter (NHE) isoforms in gills of two seawater teleosts.

    PubMed

    Claiborne, J B; Blackston, C R; Choe, K P; Dawson, D C; Harris, S P; Mackenzie, L A; Morrison-Shetlar, A I

    1999-02-01

    Both Na+/H+ exchange and the electrogenic extrusion of H+ via an H+-ATPase have been postulated to drive acid excretion across the branchial epithelium of fishes. While the H+-ATPase/Na+ channel system appears to be the predominant mechanism in some freshwater species, it may play a reduced role in seawater and brackish-water animals, where high external Na+ concentrations may thermodynamically favor Na+/H+ exchange driven by a Na+/H+ antiporter (NHE). In this study, we used molecular and immunological methods to assess the role of NHE isoforms in the branchial epithelium of the marine long-horned sculpin (Myoxocephalus octodecimspinosus) and the euryhaline killifish (Fundulus heteroclitus). Northern blot analysis of RNA probed with the human NHE-1 BamHI fragment suggested the presence of homologous gill NHE mRNA in sculpin. RT-PCR on gill RNA isolated from sculpin recovering from metabolic acidosis provided evidence for two distinct NHE isoforms; one with 76 % amino acid homology to mammalian NHE-2, and another 92 % homologous to trout erythrocytic beta-NHE. Killifish also have transcripts with 91 % homology to beta-NHE. Immunological detection using monoclonal antibodies for mammalian NHE-1 revealed a protein antigenically similar to this isoform in the gills of both species. Metabolic acidosis caused an approximately 30-fold decrease in expression of the NHE-1-like protein in sculpin. We speculate that beta-NHE in the gills plays the intracellular 'housekeeping' roles described for mammalian NHE-1. During systemic acidosis, apical gill NHE-2 (which is sensitive to external amiloride and low [Na+]) in parallel with a dramatic suppression of basolateral NHE-1 activity enhances net capdelta H+ transfers to the water. PMID:9882643

  12. The fate of residual carbon in floodplain sediments, originating from eroding peatlands

    NASA Astrophysics Data System (ADS)

    Alderson, Danielle; Evans, Martin; Rothwell, James; Boult, Stephen; Rhodes, Edward

    2016-04-01

    Fluvial systems and their associated sediments have been overlooked as part of global carbon budgets until recently. In the UK, large stores of organic carbon in peatlands are dynamically eroding, with the eventual result being 'off-site' greenhouse gas emissions, which must be incorporated into carbon budgets for management strategies. Evans et al. (2013) concluded peatland fluvial systems are active cyclers of carbon, with 50-90% of particulate organic carbon (POC) exported from peatlands eventually emitted as CO2. Floodplains, although commonly regarded as zones of carbon storage, have been identified as potential hotspots of carbon cycling in the fluvial system with a key process being decomposition of POC. Only 20% of POC may escape mineralisation on floodplains within a peatland catchment (Evans et al., 2013), but studying the composition of the residual carbon has the potential to add to understanding of the drivers of storage versus mineralisation. In this research we have examined stratigraphic records of carbon cycling by focusing on organic matter preserved in a floodplain environment downstream of the Bleaklow Plateau in the Peak District. An OSL date of 640 +/- 90 years BP and a radiocarbon date of 500-310 cal years BP from the sediment cores collected, together with an assessment of the valley morphology using high resolution LiDAR DEM's, indicate potential interaction of post glacial landslide features with the onset of substantial peat erosion, conditioning the landscape to interrupt the transport of carbon down the fluvial network. Floodplain cores have been correlated on the basis of both visual stratigraphy and geochemistry obtained by Itrax core scanning. This data is supported by targeted gas flux data from boreholes using a Gasclam. We present a rudimentary carbon budget for the floodplain of study.

  13. Concentrated flow erodibility for physically-based erosion models: temporal variability in disturbed and undisturbed rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current physically based overland flow erosion models for rangeland application do not separate disturbed and undisturbed conditions in modeling concentrated flow erosion. In this study, concentrated flow simulations on disturbed and undisturbed rangelands were used to estimate the erodibility and t...

  14. ERODIBILITY OF A SOIL DRAINAGE SEQUENCE IN THE LOESS UPLANDS OF MISSISSIPPI

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The susceptibility of loess soils in the lower Mississippi to runoff and erosion losses varies as a function of landscape position and mapping units. This study was conducted to determine the effects of soil drainage on physical and chemical properties that influence erodibility through their contr...

  15. Settling Velocity, Aggregate Stability, and Interrill Erodibility of Soils Varying in Clay Mineralogy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The relation of soil structural stability with soil erodibility depends on the mechanisms of aggregate disruption of different aggregate sizes and the measurement technique. In this study, we evaluated the relationship between settling velocity and stability of aggregates of different sizes, and int...

  16. The effect of evaporation and nutrient enrichment on the erodability of mudflats in a mesotidal estuary

    NASA Astrophysics Data System (ADS)

    Fagherazzi, S.; Viggato, T.; Vieillard, A. M.; Fulweiler, R. W.

    2014-12-01

    Large areas of mesotidal estuaries become subaerial during low tide. Here we study the effect of nutrient enrichment and several meteorological and hydrodynamic parameters on the erodability of mudflat substrates when they are emergent. We tested the impact of nutrient fertilization on tidal flat sediments over a two week period in September 2011 in Plum Island Sound, Massachusetts (USA). High resolution measurements from our experiment indicate that daily nutrient enrichment does not change the erosion threshold of the muddy substrate, nor affect the concentration of chlorophyll a at the surface. Sediment erodability is instead directly related to the potential evaporation rate and to the duration of the subaerial period. Chlorophyll a concentration decreases when evaporation is high, possibly due to the downward migration of diatoms. Sediment concentrations in the water column during submergence strongly depend on bottom shear stresses triggered by tidal currents. Surprisingly, they are also related to the total evaporation that occurred in the previous emergence period. We conclude that subaerial desiccation at low tide decreases the erodability of mudflat sediments. This strengthening effect is not lost during the following submerged period, thus limiting the erosive effect of tidal currents. For the first time we show that not only subaqueous but also subaerial processes control the erodability of mudflats. Global warming and other climatic variations regulating long-term evaporation rates can therefore directly affect the stability of mudflats in mesotidal environments.

  17. Solute Transport in Eroded and Rehabilitated Prairie Landforms. 2. Reactive Solute

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information regarding the impact of varying soil, landscape, and climate conditions on the off-site transport of pesticides is critical to the development of improved pesticide management practices. We quantified the rate of S-metolachlor dissipation after fall and spring application in eroded and r...

  18. Using landscape restoration to increase crop yield on severely eroded hilltops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage is a dominant soil erosion process in cultivated hilly landscapes and is responsible for local soil redistribution with the landscape. Topsoil is lost from upper slope positions and accumulates in lower slope positions and depressions. Ultimately, the loss of topsoil on eroded upper slope po...

  19. Soil Properties and Productivity as Affected by Topsoil Movement within an Eroded Landform

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In hilly landforms subject to long-term cultivation, erosion has denuded upper slope positions of topsoil and accumulated topsoil in lower slope positions. One approach to remediate these eroded landforms is moving soil from areas of topsoil accumulation to areas of topsoil depletion, termed here so...

  20. Soil erodibility: A comparison between the Jet Erosion Test and the Hole Erosion Test

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The erosion behavior of clay soils is important for many applications within water resources (i.e. earthen spillway erosion, river channel erosion, bank stability, and dam, and levee failures). The objective of this study was to compare soil erodibility results of two different erosion testing devi...

  1. Restoration of Degraded/Eroded Soil under Different Management Practices in the Central Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Farmlands in the Central Great Plains Region (CGPR) have lost topsoil through wind and water erosion induced by tillage and poor soil management. These soils are now degraded with low soil quality and productivity. Productivity and quality of degraded/eroded soils can be restored using manure and i...

  2. No-Till Management Effects on Soil Water and Wind Erodibility Parameters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extent to which no-till management improves water and wind erodibility parameters is not well understood. This study assessed changes in aggregate resistance to raindrops, dry aggregate wettability, and dry aggregate stability as well as their relationships with changes in soil organic carbon co...

  3. 7 CFR 1412.68 - Compliance with highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Compliance with highly erodible land and wetland conservation provisions. 1412.68 Section 1412.68 Agriculture Regulations of the Department of Agriculture... and wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  4. 7 CFR 1412.68 - Compliance with highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Compliance with highly erodible land and wetland conservation provisions. 1412.68 Section 1412.68 Agriculture Regulations of the Department of Agriculture... and wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  5. 7 CFR 1412.68 - Compliance with highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Compliance with highly erodible land and wetland conservation provisions. 1412.68 Section 1412.68 Agriculture Regulations of the Department of Agriculture... and wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  6. 7 CFR 1430.225 - Violations of highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Violations of highly erodible land and wetland conservation provisions. 1430.225 Section 1430.225 Agriculture Regulations of the Department of Agriculture... wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  7. 7 CFR 1430.225 - Violations of highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Violations of highly erodible land and wetland conservation provisions. 1430.225 Section 1430.225 Agriculture Regulations of the Department of Agriculture... wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  8. 7 CFR 1430.225 - Violations of highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Violations of highly erodible land and wetland conservation provisions. 1430.225 Section 1430.225 Agriculture Regulations of the Department of Agriculture... wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  9. 7 CFR 1430.225 - Violations of highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 10 2014-01-01 2014-01-01 false Violations of highly erodible land and wetland conservation provisions. 1430.225 Section 1430.225 Agriculture Regulations of the Department of Agriculture... wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  10. 7 CFR 1412.68 - Compliance with highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 10 2013-01-01 2013-01-01 false Compliance with highly erodible land and wetland conservation provisions. 1412.68 Section 1412.68 Agriculture Regulations of the Department of Agriculture... and wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  11. 7 CFR 1430.225 - Violations of highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 10 2012-01-01 2012-01-01 false Violations of highly erodible land and wetland conservation provisions. 1430.225 Section 1430.225 Agriculture Regulations of the Department of Agriculture... wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  12. 7 CFR 1412.68 - Compliance with highly erodible land and wetland conservation provisions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 10 2011-01-01 2011-01-01 false Compliance with highly erodible land and wetland conservation provisions. 1412.68 Section 1412.68 Agriculture Regulations of the Department of Agriculture... and wetland conservation provisions. The provisions of part 12 of this title apply to this part....

  13. Submandibular gland megalith eroding the floor of the mouth: a case report.

    PubMed

    Singh, Sourav; Singh, Smita

    2013-12-01

    Sialolithiasis is the most common pathologic condition affecting the salivary glands. However, large sialoliths (megaliths) are considered rare. The submandibular glands are more susceptible to stone formation than are the other salivary glands. We describe the case of a 55-year-old man with an unusually large sialolith that had eroded the floor of the mouth. PMID:24366709

  14. Influence of FGD gypsum on the properties of a highly erodible soil under conservation tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The performance of conservation tillage practices imposed on highly erodible soils may be improved by the use of amendments with a high solubility rate, and whose dissolution products are translocated at depth in the soil profile faster than normally used agricultural lime and fertilizer products. T...

  15. Erodibility of a mixed mudflat dominated by microphytobenthos and Cerastoderma edule, East Frisian Wadden Sea, Germany

    NASA Astrophysics Data System (ADS)

    Andersen, T. J.; Lanuru, M.; van Bernem, C.; Pejrup, M.; Riethmueller, R.

    2010-04-01

    Sediment erodibility and a range of physical and biological parameters were measured at an intertidal site in the German Wadden Sea area in June, September and November 2002 and February and April 2003 in order to examine the influence of macrozoobenthos and microphytobenthos on sediment erodibility and the temporal variation. The study site was a mixed mudflat situated in the mesotidal Baltrum-Langeoog tidal basin at the East Frisian barrier coast. The mud content at the site was about 35% and the filter-feeding cockle Cerastoderma edule was the dominating macrozoobenthic species (by biomass). The erodibility of the sediment showed strong temporal variation with high erosion thresholds in spring and late summer and significantly lower thresholds during the rest of the study period. The erosion thresholds were strongly dependent on the contents of chlorophyll a (chl a) and colloidal carbohydrates, both indicators of the content of microphytobenthos, in this environment primarily benthic diatoms. The content of microphytobenthos was high in September 2002 and April 2003, and regression analysis indicated that this was the only likely reason for the low erodibility found at these times. A biostabilisation index of about 4.5 was found for a situation with both abundant biofilms and cockles. A direct influence of Cerastoderma edule on erodibility was not observed, in contrast to other recent studies. The presence of C. edule at the site results in biodeposition of fine-grained material and the presence of C. edule will therefore probably increase the content of fine-grained sediments at the surface compared to an abiotic situation. Increasing the amount of fine-grained material in mixed sediments has previously been shown to reduce the erodibility of the sediments and C. edule will therefore in this way indirectly stabilize the bed. However, although C. edule may constitute the main part of the biomass at some intertidal sites, other and more vigorous bioturbators and

  16. Landslides falling onto a shallow erodible substrate or water layer: an experimental and numerical approach

    NASA Astrophysics Data System (ADS)

    Crosta, G. B.; De Blasio, F. V.; Locatelli, M.; Imposimato, S.; Roddeman, D.

    2015-09-01

    Landslides often collapse in areas covered by alluvial deposits forming an erodible layer. This erodible substrate may deform plastically under the intense shear stress of the landslide mass. In other cases, the collapse occurs onto a water basin or tidal flat, creating impulse water waves whilst the landslide may be lubricated by a water layer underneath. In either cases the presence of a medium underneath the landslide will change its dynamics introducing complex processes. While frictional, dry masses and taluses generally hamper the landslide motion. In this work, we present some experiments mimicking the collapse of a landslide onto shallow erodible or water layers. The landslide is simulated with a granular material (sand or gravel) flowing on an incline (35-66°) followed by a horizontal sector covered with a granular bed 1 to 2 cm thick or with a 0.5-1 cm of water. Monitoring evolution in time allows us to describe in detail the process of fluidization of the material at impact, the generation of impact waves, and the erosion process. Concerning impact on a sand layer, the apparent friction coefficient (H/L) is found to increase with the chute slope angle and with the thickness of the erodible layer, and to decrease with the volume. At low slope angles, the material accumulates backwards in a shock wave mode, while at larger slope angles (>45°) it accumulates by prograding forward. A granular avalanche falling from the slope is partially reflected at the sharp slope break where erosion occurs and then propagates initially as a wave partially eroding the superficial material. Folding and thrusting occur within the dense shear flow and the erodible layer. Experiments with a water layer show that the dynamics depends much on the permeability of the granular avalanche. FEM numerical simulations replicate and allow to describe and understand both the spreading and the erosion, and internal deformation recorded in the erodible layer. Experimental findings are

  17. Redox proteomic analysis of mytilus edulis gills: effects of the pharmaceutical diclofenac on a non-target organism.

    PubMed

    Jaafar, Siti Nur Tahirah; Coelho, Ana Varela; Sheehan, David

    2015-10-01

    Veterinary and human pharmaceuticals are an emerging category of chemical pollutants with potential to cause serious toxicity to non-target organisms. Filter-feeding aquatic organisms such as mussels are especially threatened. In this study, the blue mussel, Mytilus edulis, was exposed to two doses (0.2 mg/L and 1 mg/L) of the anti-inflammatory diclofenac. Effects on the gill, the principal feeding organ of mussels, were investigated. It was noted that, while no effect was evident on gill glutathione transferase or catalase activities, there was a tissue-specific increase in glutathione reductase activity and reduction in total protein thiol groups. Two dimensional electrophoresis was performed and some affected proteins identified by in-gel tryptic digestion and peptide mass fingerprinting. Of these, four unique proteins (caspase 3/7-4, heat-shock cognate protein 70, a predicted enolase-like protein, arginine kinase) were found to be oxidized whilst eight unique proteins (β-tubulin, actin, isocitrate dehydrogenase, arginine kinase, heavy metal-binding HIP, cytosolic malate dehydrogenase, proteasome subunit alpha type 2, Mg: bb02e05 (glyceraldehyde-3-phosphate dehydrogenase) and superoxide dismutase) were found to have altered abundance. In addition, bioinformatic analysis suggested putative identities for six hypothetical proteins which either were oxidized or decreased in abundance. These were; 78 kDa glucose-regulated protein precursor, α-enolase, calreticulin, mitochondrial H + -ATPase, palmitoyl protein thioesterase 1 and initiation factor 5a. It is concluded that diclofenac causes significant oxidative stress to gills and that this affects key structural, metabolic and stress-response proteins. PMID:25833337

  18. Trout gill cells in primary culture on solid and permeable supports.

    PubMed

    Leguen, I; Cauty, C; Odjo, N; Corlu, A; Prunet, P

    2007-12-01

    Trout gill cells in primary culture on solid and permeable supports were compared. Cultures were carried out by directly seeding cells on each support after gill dissociation. Most of the cell types present in culture were similar, regardless of culture support (pavement cells, mucous cells (3-4%), but no mitochondria-rich cells). However, insertion of mucous cells in cultured epithelium on permeable support presented a morphology more similar to gills in situ. Gene expression of ion transporters and hormonal receptors indicated similar mRNA levels in both systems. Cortisol inhibited cell proliferation on both supports and maintained or increased the total cell number on solid and permeable membranes, respectively. This inhibition of mitosis associated with an increase or maintenance of total gill cells suggests that cortisol reduced cell degeneration. In the presence of cortisol, transepithelial resistance of cultured gill cells on permeable membranes was increased and maintained for a longer time in culture. In conclusion, gill cells in primary culture on permeable support present: (i) a morphology more similar to epithelium in situ; and (ii) specific responses to cortisol treatment. New findings and differences with previous studies on primary cultures of trout gill cells on permeable membrane are discussed. PMID:17977040

  19. Intraspecific variation in gill morphology of juvenile Nile perch, Lates niloticus, in Lake Nabugabo, Uganda

    USGS Publications Warehouse

    Paterson, Jaclyn A.; Chapman, Lauren J.; Schofield, Pamela J.

    2010-01-01

    Several studies have demonstrated intraspecific variation in fish gill size that relates to variation in dissolved oxygen (DO) availability across habitats. In Lake Nabugabo, East Africa, ecological change over the past 12 years has coincided with a shift in the distribution of introduced Nile perch such that a larger proportion of the population now inhabits waters in or near wetland ecotones where DO is lower than in open waters of the lake. In this study, we compared gill size of juvenile Nile perch between wetland and exposed (open-water) habitats of Lake Nabugabo in 2007, as well as between Nile perch collected in 1996 and 2007. For Nile perch of Lake Nabugabo [<20 cm total length (TL)], there was a significant habitat effect on some gill traits. In general, fish from wetland habitats were characterized by a longer total gill filament length and average gill filament length than conspecifics from exposed habitats. Nile perch collected from wetland areas in 2007 had significantly larger gills (total gill filament length) than Nile perch collected in 1996, but there was no difference detected between Nile perch collected from exposed sites in 2007 and conspecifics collected in 1996.

  20. Microbial proliferation on gill structures of juvenile European lobster ( Homarus gammarus) during a moult cycle

    NASA Astrophysics Data System (ADS)

    Middlemiss, Karen L.; Urbina, Mauricio A.; Wilson, Rod W.

    2015-12-01

    The morphology of gill-cleaning structures is not well described in European lobster ( Homarus gammarus). Furthermore, the magnitude and time scale of microbial proliferation on gill structures is unknown to date. Scanning electron microscopy was used to investigate development of setae in zoea, megalopa and juvenile stages (I-V). Microbes were classified and quantified on gill structures throughout a moult cycle from megalopa (stage IV) to juvenile (stage V). Epipodial serrulate setae, consisting of a naked proximal setal shaft with the distal portion possessing scale-like outgrowths (setules), occur only after zoea stage III. After moulting to megalopa (stage IV), gill structures were completely clean and no microbes were visible on days 1 or 5 postmoult. Microbial proliferation was first evident on day 10 postmoult, with a significant 16-fold increase from day 10 to 15. Rod-shaped bacteria were initially predominant (by day 10); however, by day 15 the microbial community was dominated by cocci-shaped bacteria. This research provides new insights into the morphology of gill-grooming structures, the timing of their development, and the magnitude, timescale and characteristics of gill microbial proliferation during a moult cycle. To some degree, the exponential growth of epibionts on gills found during a moult cycle will likely impair respiratory (gas exchange) and ion regulatory function, yet further research is needed to evaluate the physiological effects of the exponential bacterial proliferation documented here.

  1. Hatching timing, oxygen availability, and external gill regression in the tree frog, Agalychnis callidryas.

    PubMed

    Warkentin, Karen M

    2002-01-01

    The physiological role of the embryonic external gills in anurans is equivocal. In some species, diffusion alone is clearly sufficient to supply oxygen throughout the embryonic period. In others, morphological elaboration and environmental regulation of the external gills suggest functional importance. Since oxygen stress is a common trigger of hatching, I examined the relationships among hatching timing, oxygen stress, and external gill loss. I worked with the red-eyed tree frog, Agalychnis callidryas, a species with arboreal eggs and aquatic tadpoles in which gill regression is associated with hatching, and hatching timing affects posthatching survival with aquatic predators. Both exposure to a hypoxic gas mixture and submergence in water, a natural context in which hypoxic stress can occur, induced early hatching. Exposure to hyperoxic gas mixtures induced regression of external gills, and subsequent exposure to air induced early hatching. Prostaglandin-induced external gill regression also induced hatching, and this effect was partially ameliorated by exposure to hyperoxic gas. Together, these results suggest that external gills enhance the oxygen uptake of embryos and are necessary to extend embryonic development past the onset of hatching competence. PMID:12024291

  2. Cortisol differentially alters claudin isoforms in cultured puffer fish gill epithelia.

    PubMed

    Bui, Phuong; Bagherie-Lachidan, Mazdak; Kelly, Scott P

    2010-04-12

    A primary cultured gill epithelium from the puffer fish Tetraodon nigroviridis was developed to examine the corticosteroid regulation of claudin isoform mRNA abundance in fish gills. Preparations were composed of polygonal epithelial cells exhibiting concentric apical microridges and zonula occludens-1 immunoreactivity along cell margins. No evidence was found to indicate the presence of Na(+)-K(+)-ATPase-immunoreactive or mitochondria-rich cells in cultured preparations. Therefore, epithelia appear to be composed of gill pavement cells (PVCs) only. An RT-PCR profile of 12 salinity responsive gill claudin tight junction (TJ) proteins (Tncldn3a, -3c, -6, -8d, -10d, -10e, -11a, -23b, -27a, -27c, -32a, and -33b) revealed the absence of Tncldn6, -10d and -10e in cultured epithelia, suggesting that these isoforms are not associated with gill PVCs. Cortisol treatment of cultured epithelia dose-dependently increased or decreased mRNA abundance of select claudin isoforms. Transcript abundance of several claudin isoforms was unaffected by cortisol treatment. These data provide evidence for the cell specific distribution of claudins in fish gills and suggest that heterogeneous alterations in the abundance of select claudin isoforms contribute to the corticosteroid regulation of gill permeability. PMID:19969041

  3. Structural changes in gill DNA reveal the effects of contaminants on Puget Sound fish.

    PubMed Central

    Malins, Donald C; Stegeman, John J; Anderson, Jack W; Johnson, Paul M; Gold, Jordan; Anderson, Katie M

    2004-01-01

    Structural differences were identified in gill DNA from two groups of English sole collected from Puget Sound, Washington, in October 2000. One group was from the industrialized Duwamish River (DR) in Seattle and the other from relatively clean Quartermaster Harbor (QMH). Chemical markers of sediment contamination [e.g., polynuclear aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs)] established that the DR was substantially more contaminated than QMH. The levels of these chemicals in the sediments of both sites were consistent with levels of cytochrome P450 1A (CYP1A) expression in the gills of English sole from the same sites. Structural differences in gill DNA between the groups were evinced via statistical models of Fourier transform-infrared (FT-IR) spectra. Marked structural damage was found in the gill DNA of the DR fish as reflected in differences in base functional groups (e.g., C-O and NH2) and conformational properties (e.g., arising from perturbations in vertical base stacking interactions). These DNA differences were used to discriminate between the two fish groups through principal components analysis of mean FT-IR spectra. In addition, logistic regression analysis allowed for the development of a "DNA damage index" to assess the effects of contaminants on the gill. The evidence implies that environmental chemicals contribute to the DNA changes in the gill. The damaged DNA is a promising marker for identifying, through gill biopsies, contaminant effects on fish. PMID:15064153

  4. Evolution of the branchiostegal membrane and restricted gill openings in Actinopterygian fishes.

    PubMed

    Farina, Stacy C; Near, Thomas J; Bemis, William E

    2015-06-01

    A phylogenetic survey is a powerful approach for investigating the evolutionary history of a morphological characteristic that has evolved numerous times without obvious functional implications. Restricted gill openings, an extreme modification of the branchiostegal membrane, are an example of such a characteristic. We examine the evolution of branchiostegal membrane morphology and highlight convergent evolution of restricted gill openings. We surveyed specimens from 433 families of actinopterygians for branchiostegal membrane morphology and measured head and body dimensions. We inferred a relaxed molecular clock phylogeny with branch length estimates based on nine nuclear genes sampled from 285 species that include all major lineages of Actinopterygii. We calculated marginal state reconstructions of four branchiostegal membrane conditions and found that restricted gill openings have evolved independently in at least 11 major actinopterygian clades, and the total number of independent origins of the trait is likely much higher. A principal component analysis revealed that fishes with restricted gill openings occupy a larger morphospace, as defined by our linear measurements, than do fishes with nonrestricted openings. We used a decision tree analysis of ecological data to determine if restricted gill openings are linked to certain environments. We found that fishes with restricted gill openings repeatedly occur under a variety of ecological conditions, although they are rare in open-ocean pelagic environments. We also tested seven ratios for their utility in distinguishing between fishes with and without restricted gill openings, and we propose a simple metric for quantifying restricted gill openings (RGO), defined as a ratio of the distance from the ventral midline to the gill opening relative to half the circumference of the head. Functional explanations for this specialized morphology likely differ within each clade, but its repeated evolution indicates a need

  5. Development a fluvial detachment rate model to predict the erodibility of cohesive soils under the influence of seepage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seepage influences the erodibility of streambanks, streambeds, dams, and embankments. Usually the erosion rate of cohesive soils due to fluvial forces is computed using an excess shear stress model, dependent on two major soil parameters: the critical shear stress (tc) and the erodibility coefficie...

  6. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  7. Does crustacean ethoxyresorufin O-deethylase activity vary during the molting cycle?

    PubMed

    Hotard, Kate; Zou, Enmin

    2013-10-01

    The authors examined fluctuation in microsomal ethoxyresorufin O-deethylase (EROD) activity in the hepatopancreas during the molting cycle of the fiddler crab, Uca pugilator. Results showed that microsomal EROD activity fluctuates significantly during the molting cycle, with the lowest enzymatic activity occurring in the late premolt stage. These results clearly show that molting physiology influences crustacean EROD activity, suggesting that when using crustacean EROD assays in evaluating pollution, only individuals from the same molt stage should be used. The authors propose that the high level of EROD activity in postmolt and intermolt stages is an additional mechanism crustaceans use to prevent any untimely rise in ecdysteroid levels. PMID:23843096

  8. Gilles de la Tourette's criminal women: the many faces of fin de siècle hypnotism.

    PubMed

    Bogousslavsky, Julien; Walusinski, Olivier

    2010-09-01

    Gilles de la Tourette is now known for the disease which now bears his name, but his activities in the management of hysterics and in hypnotism, which gained him most of his lifetime reputation, have been largely forgotten. As one of the closest followers of Jean-Martin Charcot, he always remained faithful to his mentor's views, and was one of the most vehement defenders of La Salpêtrière school during the quarrel with Hippolyte Bernheim and the Nancy school on the question of the specificity of hypnotic susceptibility in hysteria. This controversy became critical during medico-legal assessment of crimes supposedly committed under hypnotic suggestion. Gilles de la Tourette's involvement in criminal hypnotism was striking, as shown by his own experiments, the most famous of which being his suggested poisoning of a colleague by Blanche Wittman, the celebrated Charcot's hysteric patient in the 1887 Brouillet's painting. Gilles de la Tourette also acted as expert in murder trials, and his Epilogue in the Gouffé's trunk case, where he affirmed that no murder in real life could be due to hypnotism, and considered that Gabrielle Bompard, the murderer's accomplice, was not under hypnotic suggestion, had a considerable impact. Finally, he was confronted to the issue of murder under hypnotism in his private life, since in 1893, a former patient, Rose Kamper, came and shot him in the head at his home, claiming that hypnotism sessions had changed her own person, and that she had been hypnotized "at distance". These acts from three very different "hysterical" women highlight the Salpêtrière's theories on hypnotism and their inner contradictions in the fin de siècle ambiance, a few years before Joseph Babinski renewed the concepts on hysteria. PMID:20413214

  9. Use of rare earth oxide tracers to determine source areas for sediment eroded from arable hillslopes

    NASA Astrophysics Data System (ADS)

    Deasy, C.; Quinton, J. N.

    2009-04-01

    Soil erosion from arable hillslopes has both on-site and off-site effects. On-site, erosion and redistribution of sediment can lead to the loss of productive field area and a reduction in organic matter and nutrient content in topsoil. Off-site, the transport and deposition of eroded sediment in downstream waters is associated with turbidity, sedimentation and reduced water quality, as sediments are associated with the transport of nutrients, particularly phosphorus (P) and nitrogen (N), heavy metals and pesticides. Arable land is a major source for these sediments, with studies in the UK estimating the cultivated fields may be responsible for up to 80% of particulate P in rivers. Previous studies at Loddington in Leicestershire, UK have demonstrated that most of the P and much of the N eroded from hillslope is in particulate form, transported in association with sediment suspended in runoff. Results also suggest that tramlines are the principal pathway for erosion from arable fields containing combinable crops. As tramlines are regularly spaced over the whole field, they potentially act as conduits for runoff, sediment and sediment-associated nutrients to be lost from the hillslope. However, it is not yet clear where the source areas are for sediment eroded via this pathway. To understand the movement of sediment on arable hillslopes, a hillslope-scale tracer experiment was undertaken in one year at the same site. The aims of this study were (1) to develop an application method for rare earth oxide tracers suitable for using on a hillslope scale to assess sediment movement over a number of storm events, (2) to determine the erosion rates of different contributing hillslope areas, (3) to determine the relative contributions of sediment eroded from each of these areas in order to assess the importance of different hillslope source areas for soil erosion. Different rare earth oxide tracers were applied in solution using a knapsack sprayer to four areas of the

  10. Relevance of macrozoobenthic grazers to understand the dynamic behaviour of sediment erodibility and microphytobenthos resuspension in sunny summer conditions

    NASA Astrophysics Data System (ADS)

    Orvain, Francis; Guizien, Katell; Lefebvre, Sébastien; Bréret, Martine; Dupuy, Christine

    2014-09-01

    The quantification of overall microphytobenthos productivity should include the export of biomass from the intertidal zone during high tides, which implies refined estimates and concepts of erosion parameters. For the first time, the export of microphytobenthic cells was assessed over an intertidal mudflat in the Marennes-Oléron Bay, France, during a complete spring/neap tide modulation. In the summer of 2008, resuspension rates of chl-a exported only reached 2.5% of the standing stock of benthic diatoms on each day. Sedimentary factors failed to explain any variation regarding bed and microphytobenthos erodibility. During the early fluff layer erosion phase, there were negative effects of grazing activities exerted by motile infauna (Peringia ulvae) on erosion fluxes of chl-a, while there was a related positive correlation with pheopigment proportion. The erosion process plays an important role in this vegetal-herbivore interaction by reinforcing the decline of the microphytobenthic biomass and provoking a catastrophic shift to mass erosion after a sequence of several days of co-occurring intense grazing by snails and chl-a decline. During mass erosion, the biofilm decline explained the variations of sediment erodibility, with a marked negative correlation between bound extracellular polymeric substance (EPS) proteins and critical threshold for bed erosion, in contrast with the commonly observed positive influence of EPS secretion on bed resistance. The complex nature of the effects of EPS by microphytobenthos must be further investigated to unravel their complex role in bioengineering sediments. The increase of protein proportion in EPS could provide specific properties related to hydrophilic features. Nevertheless, the level of grazing pressure by P. ulvae should be so intense that the top-down control must explain this original finding, since there was a positive correlation of proteins in EPS and snail density that could be related to mucus secretion (as a

  11. Finding Eroding Areas and Patterns with GIS, Caesium-137 Tracers, and Community Knowledge in the Ethiopian Highlands

    NASA Astrophysics Data System (ADS)

    Guzman, C. D.; Tilahun, S. A.; Zegeye, A. D.; Yitaferu, B.; Steenhuis, T. S.

    2012-12-01

    While soil erosion has been reducing agricultural productivity in developing countries for decades, its effects and seriousness are gaining more attention, especially with respect to shortening the life of reservoirs for hydroelectric power generation. This has urged policy makers to develop comprehensive sustainable strategies for environmental conservation. To develop such strategies, however, assumptions made within the different areas of knowledge that concurrently study soil conservation must be challenged and verified. A central aim of this study on soil erosion and conservation is to bridge between social science and engineering disciplines by comparing and contrasting estimates and identification of eroding areas and patterns. In Debre Mewi, Ethiopia, we examine spatial and temporal variations in erosion from an agricultural watershed and its subsequent soil nutrient changes using GIS-based erosion prediction tools, the soil-adsorbed radionuclide caesium-137 as a sediment tracer, and community knowledge. We plan to reconcile differences between theoretical formulations, actual measurements, and community perceptions and insight. Sixteen sites are monitored in this small watershed 50 km south of Lake Tana, with characteristic semi-monsoonal rains, during the long (kremt) rainy season for topsoil depth change, water table height, soil nutrients (N, P, K, Mg, Ca), and ceasium-137 inventory. While focus group discussions and transect walks with the community describe spring flow paths, saturated areas, degraded areas and active gullies as primary zones of erosion, GIS-based prediction tools treat steep slopes and cropped land as areas vulnerable to erosion. Cs-137 tracers map the upland mildly sloping areas to be eroding at a greater average rate than any of the mid-slope or toe-slope areas. Finally, from these comparisons, we draw information helpful in understanding why and how sediment concentration and erosion decreases and what impact we can expect to see

  12. Gills as a glutathione-dependent metabolic barrier in Pacific oysters Crassostrea gigas: Absorption, metabolism and excretion of a model electrophile.

    PubMed

    Trevisan, Rafael; Mello, Danielle F; Delapedra, Gabriel; Silva, Danilo G H; Arl, Miriam; Danielli, Naissa M; Metian, Marc; Almeida, Eduardo A; Dafre, Alcir L

    2016-04-01

    The mercapturic acid pathway (MAP) is a major phase II detoxification route, comprising the conjugation of electrophilic substances to glutathione (GSH) in a reaction catalyzed by glutathione S-transferase (GST) enzymes. In mammals, GSH-conjugates are exported from cells, and the GSH-constituent amino acids (Glu/Gly) are subsequently removed by ectopeptidases. The resulting Cys-conjugates are reabsorbed and, finally, a mercapturic acid is generated through N-acetylation. This pathway, though very well characterized in mammals, is poorly studied in non-mammalian biological models, such as bivalve mollusks, which are key organisms in aquatic ecosystems, aquaculture activities and environmental studies. In the present work, the compound 1-chloro-2,4-dinitrobenzene (CDNB) was used as a model electrophile to study the MAP in Pacific oysters Crassostrea gigas. Animals were exposed to 10μM CDNB and MAP metabolites were followed over 24h in the seawater and in oyster tissues (gills, digestive gland and hemolymph). A rapid decay was detected for CDNB in the seawater (half-life 1.7h), and MAP metabolites peaked in oyster tissues as soon as 15min for the GSH-conjugate, 1h for the Cys-conjugate, and 4h for the final metabolite (mercapturic acid). Biokinetic modeling of the MAP supports the fast CDNB uptake and metabolism, and indicated that while gills are a key organ for absorption, initial biotransformation, and likely metabolite excretion, hemolymph is a possible milieu for metabolite transport along different tissues. CDNB-induced GSH depletion (4h) was followed by increased GST activity (24h) in the gills, but not in the digestive gland. Furthermore, the transcript levels of glutamate-cysteine ligase, coding for the rate limiting enzyme in GSH synthesis, and two phase II biotransformation genes (GSTpi and GSTo), presented a fast (4h) and robust (∼6-70 fold) increase in the gills. Waterborne exposure to electrophilic compounds affected gills, but not digestive gland

  13. Structural elements of the gills of the shore crab Carcinus mediterraneus

    NASA Astrophysics Data System (ADS)

    Venezia, L. Dalla; Zago, C.; Siebers, D.; Menetto, A.

    1992-12-01

    Fine structural studies were conducted on the gills of the shore crab Carcinus mediterraneus using scanning electron microscopic techniques. The results obtained show the structural organization of crab gills from whole gills including spiny elements over the 150 lamellae to lamellar components such as cuticles, median shaft, marginal canal, afferent and efferent lamellar vessels and hemolymph cells. Enormous surface enlargement is accomplished by a variety of structural elements which allow rapid circulation of hemolymph. In the form of a relatively small organ, the gills fulfill all the necessary exchanges of specific molecules between the crab and its environment. Aggregations of ca 1-μm particles covering the outer cuticular surfaces are considered to be bacterial colonies of unknown properties and functions.

  14. Amoebic gill infection in coho salmon Oncorhynchus kisutch farmed in Korea.

    PubMed

    Kim, Wi-Sik; Kong, Kyoung-Hui; Kim, Jong-Oh; Oh, Myung-Joo

    2016-08-31

    About 70% mortality occurred in cultured coho salmon Oncorhynchus kisutch at a marine farm in the South Sea of Korea in 2014. Diseased fish showed greyish or pale patches on the gills, with no internal signs of disease. No bacteria or viruses were isolated from diseased fish, but numerous amoebae were found on the gills. Histopathological examinations revealed extensive hyperplastic epithelium and lamellar fusion in the gills. Numerous amoebae were seen between gill filaments. The amoebae had a 630 bp partial 18S rRNA gene fragment specific to Neoparamoeba perurans. Phylogenetic analysis based on partial 18S rRNA gene nucleotide sequences revealed that this Korean amoeba belonged to the N. perurans group. This is the first report of N. perurans infection in Korea. PMID:27596862

  15. Gilles de la Tourette Syndrome: A Review and Implications for Educators.

    ERIC Educational Resources Information Center

    Lemons, Laurie A.; Barber, William H.

    1991-01-01

    Gilles de la Tourette syndrome is a disorder characterized by multiple involuntary motor and verbal tics. This review covers the history, symptoms, diagnostic criteria, past and present treatments, associated disorders, and various educational techniques. (Author/DB)

  16. Ultrastructural effects on gill tissues induced in red tilapia Oreochromis sp. by a waterborne lead exposure.

    PubMed

    Aldoghachi, Mohammed A; Azirun, Mohd Sofian; Yusoff, Ismail; Ashraf, Muhammad Aqeel

    2016-09-01

    Experiments on hybrid red tilapia Oreochromis sp. were conducted to assess histopathological effects induced in gill tissues of 96 h exposure to waterborne lead (5.5 mg/L). These tissues were investigated by light and scanning electron microscopy. Results showed that structural design of gill tissues was noticeably disrupted. Major symptoms were changes of epithelial cells, fusion in adjacent secondary lamellae, hypertrophy and hyperplasia of chloride cells and coagulate necrosis in pavement cells with disappearance of its microridges. Electron microscopic X-ray microanalysis of fish gills exposed to sublethal lead revealed that lead accumulated on the surface of the gill lamella. This study confirmed that lead exposure incited a difference of histological impairment in fish, supporting environmental watch over aquatic systems when polluted by lead. PMID:27579014

  17. Artificial gills for robots: MFC behaviour in water.

    PubMed

    Ieropoulos, Ioannis; Melhuish, Chris; Greenman, John

    2007-09-01

    This paper reports on the first stage in developing microbial fuel cells (MFCs) which can operate underwater by utilizing dissolved oxygen. In this context, the cathodic half-cell is likened to an artificial gill. Such an underwater power generator has obvious potential for autonomous underwater robots. The electrical power from these devices increased proportionately with water flow rate, temperature and salinity. The current output at ambient temperature (null condition) was 32 microA and this increased by 200% (approximately 100 microA) as a result of a corresponding temperature increase (DeltaT) of 52 degrees C. Similarly, the effect of increasing the water flow rate resulted in an increase in the MFC output ranging from 135% to 150%. Furthermore, the same positive effect was recorded when artificial seawater was used instead, in which case the increase in the MFC current output was >100% (from 32 to 65 microA). There was a distinct difference in the MFC performance when operated under low turbulent as opposed to high turbulent flow rates. These findings can be advantageous in the design of underwater autonomous robots. PMID:17848787

  18. 65Zn2+ transport by isolated gill epithelial cells of the American lobster, Homarus americanus.

    PubMed

    Sá, M G; Ahearn, G A; Zanotto, F P

    2009-07-01

    Gills are the first site of impact by metal ions in contaminated waters. Work on whole gill cells and metal uptake has not been reported before in crustaceans. In this study, gill filaments of the American lobster, Homarus americanus, were dissociated in physiological saline and separated into several cell types on a 30, 40, 50, and 80% sucrose gradient. Cells from each sucrose solution were separately resuspended in physiological saline and incubated in 65Zn2+ in order to assess the nature of metal uptake by each cell type. Characteristics of zinc accumulation by each kind of cell were investigated in the presence and absence of 10 mM calcium, variable NaCl concentrations and pH values, and 100 muM verapamil, nifedipine, and the calcium ionophore A23187. 65Zn2+ influxes were hyperbolic functions of zinc concentration (1-1,000 microM) and followed Michaelis-Menten kinetics. Calcium reduced both apparent zinc binding affinity (K (m)) and maximal transport velocity (J (max)) for 30% sucrose cells, but doubled the apparent maximal transport velocity for 80% sucrose cells. Results suggest that calcium, sodium, and protons enter gill epithelial cells by an endogenous broad-specificity cation channel and trans-stimulate metal uptake by a plasma membrane carrier system. Differences in zinc transport observed between gill epithelial cell types appear related to apparent affinity differences of the transporters in each kind of cell. Low affinity cells from 30% sucrose were inhibited by calcium, while high affinity cells from 80% sucrose were stimulated. 65Zn2+ transport was also studied by isolated, intact, gill filament tips. These intact gill fragments generally displayed the same transport properties as did cells from 80% sucrose and provided support for metal uptake processes being an apical phenomenon. A working model for zinc transport by lobster gill cells is presented. PMID:19198852

  19. Pathomorphological changes in gills of fish fingerlings (Cirrhina mrigala) by linear alkyl benzene sulfonate

    SciTech Connect

    Misra, V.; Lal, H.; Chawla, G.; Viswanathan, P.N.

    1985-12-01

    Fish fingerlings (Cirrhina mrigala) exposed to 0.005 ppm (25% of LC50) concentration to detergents (linear alkyl benzene sulfonate) showed marked behavioral changes and distorted appearance of primary and secondary lamellae along with damage to gill epithelium under scanning electron microscopy at various magnifications. Mucosal cells of gills were found to secrete mucus showing primary reactions for membrane damage leading to dysfunction in respiration and osmoregulation.

  20. Prevalence, site and tissue preference of myxozoan parasites infecting gills of cultured fish in Punjab (India).

    PubMed

    Kaur, Harpreet; Katoch, Anu

    2016-02-25

    Native carp species cultured in Indian farms in Punjab (catla Catla catla, rohu Labeo rohita, mrigal Cirrhinus mrigala, exotic carps such as silver carp Hypophthalmichthys molitrix, grass carp Ctenopharyngodon idella, common carp Cyprinus carpio and a catfish Sperata seenghala) were examined for the presence of myxozoan parasites infecting gills. Firstly, the gills were examined under a zoom-stereomicroscope for the presence of plasmodia. The number of plasmodia per gill was counted to determine the index for the intensity of infection. Infected tissues were processed for histology, and 3-4 µm sections of infected gills were stained with haematoxylin & eosin and Luna's method. A total of 19 species of myxosporean were found infecting various cell types in the gills. Of these, 14 species belonged to the genus Myxobolus, 3 species to the genus Thelohanellus and 2 species to the genus Henneguya. Species belonging to the genus Myxobolus formed the interlamellar and intralamellar vascular (LV) type plasmodia, and species belonging to the genus Thelohanellus and Henneguya formed intrafilamental vascular (FV) type plasmodia. Mixed infections comprising 2, 3 or 4 different myxozoan species were noted in individual fish. The most common type of parasitism was polyparasitism due to 4 myxobolids co-occuring in fish with an infection rate of 23.16%. All species caused mild to severe haemorrhagic gill disease with little clinical symptomatology. PMID:26912043

  1. Developmental evidence for serial homology of the vertebrate jaw and gill arch skeleton

    PubMed Central

    Gillis, J. Andrew; Modrell, Melinda S.; Baker, Clare V. H.

    2013-01-01

    Gegenbaur’s classical hypothesis of jaw-gill arch serial homology is widely cited, but remains unsupported by either paleontological evidence (e.g. a series of fossils reflecting the stepwise transformation of a gill arch into a jaw) or developmental genetic data (e.g. shared molecular mechanisms underlying segment identity in the mandibular, hyoid and gill arch endoskeletons). Here we show that nested expression of Dlx genes – the “Dlx code” that specifies upper and lower jaw identity in mammals and teleosts – is a primitive feature of the mandibular, hyoid and gill arches of jawed vertebrates. Using fate-mapping techniques, we demonstrate that the principal dorsal and ventral endoskeletal segments of the jaw, hyoid and gill arches of the skate Leucoraja erinacea derive from molecularly equivalent mesenchymal domains of combinatorial Dlx gene expression. Our data suggest that vertebrate jaw, hyoid and gill arch cartilages are serially homologous, and were primitively patterned dorsoventrally by a common Dlx blueprint. PMID:23385581

  2. From catchment to fish: Impact of anthropogenic pressures on gill histopathology.

    PubMed

    Fonseca, A R; Sanches Fernandes, L F; Fontainhas-Fernandes, A; Monteiro, S M; Pacheco, F A L

    2016-04-15

    Gill histopathology was investigated in barbel (Luciobarbus bocagei) and nase (Pseudochondrostoma sp.) in sub-catchments of Paiva River (Portugal) located upstream and downstream of a Waste Water Treatment Plant (WWTP). Multivariate statistical analyses were performed to set up correlations between the species sample (n=24) and injury types (8). The results discriminate well edema and vasodilatation between reference (upstream) and disturbed (downstream) samples. Using a watershed model, time series of physico-chemical parameters and heavy metal concentrations were calibrated and validated for the entire Paiva River basin as to investigate the relationship between water quality and the gill histopathology results. Increased concentrations of heavy metal downstream, specifically of zinc and lead, coincided with a higher severity of histopathological alterations in the fish gills. Significant but less evident relationship between water quality parameters and severity of gill injuries in the analyzed fish species were also observed for fecal coliforms, water temperature and manganese. Notwithstanding the location of the samples upstream and downstream of the WWTP, contamination of Paiva River and its effect on gill injuries cannot be disconnected from other punctual and diffuse pollution sources acting in different sectors within the watershed, namely agriculture and forest management. The severity of histopathological alterations in the fish gills reflected differences in the type and concentration of contaminants in Paiva River, and consequently can be viewed as valuable indicator of water quality. PMID:26851883

  3. Ultrastructural alterations in the gills of Labeo rohita fingerlings exposed to thermal extremes.

    PubMed

    Das, T; Sahu, N P; Chakraborty, S K; Chatterjee, N; Mohammed, M S; Dalvi, R S; Baruah, K; Pal, A K

    2014-02-01

    This study aimed to determine the cellular alterations in the gill of Labeo rohita exposed to lethal temperature maxima (LTM ax ) and lethal temperature minima (LTM in ) by means of transmission electron microscopy (TEM). Acclimation of advanced fingerlings of L. rohita was carried out at 26°C for 30 days. Acclimated fish were subjected to a constant rate of increase or decrease in temperature (0.3°C/min) until the LTM ax and LTM in values were reached. Dissected gills were processed for TEM, both at the end of acclimation period at ambient temperature (26°C) and at lethal temperatures. Results indicated that at ambient temperature, the gill tissues appeared normal. However, significant changes were observed at lethal temperatures. The gill tissues at lethal temperature maxima showed severely damaged lamellae, with more vacuolated space. At lethal temperature minima, gill tissues showed increased density of mitochondria. Our prima-facie report indicated that L. rohita exposed to lethal temperatures exhibited marked ultrastructural changes in the gills. PMID:23480531

  4. Mapping erodibility in dust source regions based on geomorphology, meteorology, and remote sensing

    NASA Astrophysics Data System (ADS)

    Parajuli, Sagar Prasad; Yang, Zong-Liang; Kocurek, Gary

    2014-09-01

    Mineral dust in the atmosphere has implications for Earth's radiation budget, biogeochemical cycles, hydrological cycles, human health, and visibility. Currently, the simulated vertical mass flux of dust differs greatly among the existing dust models. While most of the models utilize an erodibility factor to characterize dust sources, this factor is assumed to be static, without sufficient characterization of the highly heterogeneous and dynamic nature of dust source regions. We present a high-resolution land cover map of the Middle East and North Africa (MENA) in which the terrain is classified by visually examining satellite images obtained from Google Earth Professional and Environmental Systems Research Institute Basemap. We show that the correlation between surface wind speed and Moderate Resolution Imaging Spectroradiometer deep blue aerosol optical depth (AOD) can be used as a proxy for erodibility, which satisfactorily represents the spatiotemporal distribution of soil-derived dust sources. This method also identifies agricultural dust sources and eliminates the satellite-observed dust component that arises from long-range transport, pollution, and biomass burning. The erodible land cover of the MENA region is grouped into nine categories: (1) bedrock: with sediment, (2) sand deposit, (3) sand deposit: on bedrock, (4) sand deposit: stabilized, (5) agricultural and urban area, (6) fluvial system, (7) stony surface, (8) playa/sabkha, and (9) savanna/grassland. Our results indicate that erodibility is linked to the land cover type and has regional variation. An improved land cover map, which explicitly accounts for sediment supply, availability, and transport capacity, may be necessary to represent the highly dynamic nature of dust sources in climate models.

  5. Phosphorus Characterization and Contribution from Eroding Streambank Soils of Vermont's Lake Champlain Basin.

    PubMed

    Ishee, Eulaila R; Ross, Donald S; Garvey, Kerrie M; Bourgault, Rebecca R; Ford, Charlotte R

    2015-11-01

    Streambank erosion is an important contributor to sediment and nutrient export. This study determined total P (TP), soil-test P (Modified Morgan's, MM-P), and the degree of P saturation (DPS) in eroding riparian soils along four Lake Champlain Basin stream corridors. We investigated the relationship between these data and soil texture and with a series of GIS-derived landscape metrics. We also quantified the potential P load from eroding streambanks using remote sensing. Soil samples were taken from 76 erosion features to a depth of 90 cm on four streams in Chittenden County, Vermont. Mean concentrations of TP and MM-P were similar among the watersheds and through depth. Neither TP, MM-P, nor DPS were well related to texture. Metrics from available spatial databases for parent material, soil series, and landscape position were somewhat useful in predicting TP and MM-P. Eroding streambank soil from 2004 through 2007 in the four streams was estimated to contain from 0.5 to 3.9 Mg of TP and 1.4 to 10.9 kg MM-P. The mean DPS in each watershed was <18% and, along with low MM-P concentrations, suggests that eroded streambanks may act as sinks rather than sources of P. The portion of total nonpoint P export potentially contributed by streambank erosion ranged from 6% in the stream with the lowest erosion rate to 30% in the stream with the highest erosion rate. Based on TP values, the P contribution of these streambanks could be considerable, and more information is needed on their actual contribution to bioavailable P in receiving waters. PMID:26641326

  6. The erodibility of upland soils and the design of preafforestation drainage networks in the United Kingdom

    NASA Astrophysics Data System (ADS)

    Carling, Paul A.; Glaister, Mark S.; Flintham, Tim P.

    1997-12-01

    Hydraulic thresholds for erosion of fourteen upland mineral and organic soils were determined in a hydraulic flume. These soils are from areas to be afforested in the United Kingdom. Some of the group are erosion resistant but others are susceptible to erosion once denuded of vegetation; for example, by preafforestation ploughing. These threshold data were required to calibrate a hydraulic model for effective design of preafforestation drainage networks on a variety of soils. However, simple field measures of soil properties indicative of erosion potential would be of value to the forestry industry for management purposes. Consequently, hydraulic threshold data were related by linear regression methods to basic soil properties, including organic content, grain size, bulk density, compression strength and penetration resistance.The investigation concluded that four peat soils are not eroded by clear water velocities up to 5·7 m s-1, although a mineral bedload might induce erosion at lesser current speeds. Penetration resistance is a good field indicator of the degree of humification of the peat soils. Although selected physical parameters contribute resistance to water erosion, an increased organic content is pre-eminent in reducing erosion susceptibility in both organic and mineral soils. Although compressive strength was not indicative of soil erodibility, field measurements of penetration resistance on a variety of soils could be related to hydraulic thresholds of erosion; albeit through the construction of discriminant functions interpolated by eye. Consequently, organic content (laboratory) or penetration resistance (field) might form the basis of classifying upland soils in terms of erodibility.Mineral soils differ widely in terms of their erodibility, so that subject to further consideration, the use of ploughing for forestry cultivation might be appropriate in wider circumstances than presently recommended by the Forests and Water Guidelines. Ploughing

  7. A conservative treatment approach using direct composite resins for anterior teeth eroded by lemon sucking.

    PubMed

    Passos, Vanara Florencio; de Souza, Andre Mattos Brito; Rodrigues, Lidiany Karla Azevedo; Bombonatti, Juliana Campos Fraga Soares; Santiago, Sergio Lima

    2013-08-01

    An excessively acidic diet results in the progressive deterioration of dental health, with functional, esthetic, and biological consequences. Previously, rehabilitation required placing numerous full crowns and root canal treatments; however, with improved adhesive techniques, a more conservative approach may be utilized to preserve tooth structure. This article describes 2 cases that utilized conservative dental treatments (involving direct composite resins with minimal preparation of the tooth structure) to treat eroded dentition induced by lemon sucking. PMID:23928446

  8. Pedological Properties of the Eroding Coastline along the Beaufort Sea, Alaska

    NASA Astrophysics Data System (ADS)

    Ping, C.; Dou, F.; Fortier, D.; Jorgenson, T.; Kanevskiy, M.; Lynn, L. A.; Michaelson, G. J.; Shur, Y. L.

    2006-12-01

    The objectives of this National Science Foundation project are to monitor erosion rates, estimate the amount and fate of the organic carbon in the tundra soils and underlying permafrost eroded into the Arctic Ocean along the arctic coastline of Alaska. Five major types of coastline were identified along the Beaufort Sea coast; bay/inlet, delta, exposed bluffs, lagoon, and tapped basins. The lagoon coastal type is the major coastal type and accounts more than half of the coastline of the Beaufort Sea, followed by exposed bluffs, and delta. Both bay/inlet and tapped basins are of minor distribution. A total of fifty study sites were selected from detailed study and sampling to represent the major coastline types along the Beaufort Sea coast. At each site, pedological study was carried out along with geocryological study. In addition, the physiographic characteristics, coastal bluff elevation, and vegetation community were recorded. The coastal bluffs are 1 to 3 meters high in the western half of the coastline and reach 12 meters on the eastern half of the coastline. Descriptions of soil stratigraphy along the coast from Barrow to the Canadian boundary have confirmed the general classification of marine silts, eolian sands, and slightly pebbly sand deposits. The active layers along the bluffs ranged from few cm to over one meter deep as compared to soils 1 to 5 meters inland. Generally there was an organic horizon of 2-8 cm thick overlying an organic rich mineral horizon of eolian origin of 15-20 cm thick. Below this A and B horizon sequence there was a buried organic horizon that resulted from thaw-lake sequences from the early- middle Holocene. Below this buried organics there was a mixed organic and mineral horizon due to cryoturbation; organic materials were frost-churned into the underlying gleyed horizons. The cryoturbated organic matter reaches to 2 - 3 meters depths and all of Holocene age with C-14 dates younger than 8000 years. The basal dates of the peat

  9. Air jet erosion test on plasma sprayed surface by varying erodent impingement pressure and impingement angle

    NASA Astrophysics Data System (ADS)

    Behera, Ajit; Behera, Asit; Mishra, S. C.; Pani, S.; Parida, P.

    2015-02-01

    Fly-ash premixed with quartz and illmenite powder in different weight proportions are thermal sprayed on mild steel and copper substrates at various input power levels of the plasma torch ranging from 11 kW to 21 kW DC. The erosion test has done using Air Jet erosion test Reg (As per ASTM G76) with silica erodent typically 150-250 pm in size. Multiple tests were performed at increasing the time duration from 60 sec to 180 sec with increasing pressure (from 1 bar to 2.5 bar) and angle (60° & 90°). This study reveals that the impact velocity and impact angle are two most significant parameters among various factors influencing the wear rate of these coatings. The mechanisms and microstructural changes that arise during erosion wear are studied by using SEM. It is found that, when erodent are impacting the fresh un-eroded surface, material removal occurs by the continuous evolution of craters on the surface. Upper layer splats are removed out after 60 sec and second layer splat erosion starts. Based on these observations Physical models are developed. Some graphs plotted between mass loss-rate versus time period/impact Pressure/impact Angle gives good correlation with surface features observed.

  10. Mineralization rate of eroded organic C in Andosols of the Canary Islands.

    PubMed

    Mora, Juan Luis; Guerra, José Asterio; Armas, Cecilia María; Rodríguez-Rodríguez, Antonio; Arbelo, Carmen Dolores; Notario, Jesús Santiago

    2007-05-25

    The aim of this paper is to determine the biological dynamism of the organic C forms bonded to soil particles mobilized by water erosion in Andosols of the Canary Islands, to evaluate their susceptibility towards mineralization processes and the role of sediments as sources or sinks of atmospheric CO(2) in these soils. The study was carried out in Tenerife (Canary Islands) on three 200 m(2) experimental plots of the RESEL Programme on silic Andosols under forest, 3 years after being subjected to clear-cutting. Eroded sediments were collected for analysis from five significant winter rainfall episodes. For each event, samples of surface (0-5 cm) soil in situ were also collected. CO(2)-C was measured by incubation in all the samples, as well as microbial biomass-linked C. The results obtained show an enrichment in the eroded sediments of microbial biomass (7.5+/-1.6 g kg(-1) vs. 3.8+/-1.5 g kg(-1)) and of potentially mineralizable C (1419 mg CO(2)-C kg(-1) vs. 386 mg CO(2)-C kg(-1)). In addition, there was twice as much mineralization of C compounds in eroded sediments as in the soil surface horizon. PMID:17292946

  11. The effects of flocculation and bed erodibility on modeling cohesive sediment resuspension

    NASA Astrophysics Data System (ADS)

    Son, Minwoo; Hsu, Tian-Jian

    2011-03-01

    Flocculation and bed erodibility are two main processes causing the transport of cohesive sediments to be more complicated than typical noncohesive sediments. Earlier flocculation models assume a constant fractal dimension and/or a constant floc yield strength. However, recent studies have shown that considering both the fractal dimension and the floc yield strength to be variable is critical to the prediction of temporal evolution of floc size. Due to consolidation, it is also well established that critical bed shear stress of a mud bed cannot be parameterized as a constant. This study further investigates how flocculation models with different degrees of complexity and bed erodibility can affect the resulting cohesive sediment resuspension driven by tidal flows. A one-dimensional vertical numerical model for sediment transport is revised to incorporate modules for flocculation and bed erodibility. Model results are compared with data measured in the Ems/Dollard estuary. Model study suggests that it is important to incorporate variable critical shear stress in order to properly model the supply of sediment from the bed. When flocculation is neglected or incorporated incompletely, numerical model predicts nearly zero sediment concentration during slack water and very steep concentration gradient, which are inconsistent with the observed data. When the fractal dimension and the floc yield strength are both considered to be variable, the numerical model predicts much smaller settling velocity and hence captures the more well-mixed condition consistent with field observations.

  12. Erodibility of cohesive streambeds in the loess area of the midwestern USA

    NASA Astrophysics Data System (ADS)

    Hanson, G. J.; Simon, A.

    2001-01-01

    Excess stress parameters, critical shear stress (c) and erodibility coefficient (kd), for degrading channels in the loess areas of the midwestern USA are presented based on in situ jet-testing measurements. Critical shear stress and kd are used to define the erosion resistance of the streambed. The jet-testing apparatus applies hydraulic stresses to the bed and the resulting scour due to the impinging jet is related to the excess stress parameters. Streams tested were primarily silt-bedded in texture with low densities, which is typical of loess soils. Results indicate that there is a wide variation in the erosion resistance of streambeds, spanning six orders of magnitude for c and four orders of magnitude for kd. Erosion resistance was observed to vary within a streambed, from streambed to streambed, and from region to region. An example of the diversity of materials within a river system is the Yalobusha River Basin in Mississippi. The median value of c for the two primary bed materials, Naheola and Porters Creek Clay Formations, was 1·31 and 256 Pa, respectively. Streambeds composed of the Naheola Formation are readily eroded over the entire range of shear stresses, whereas only the deepest flows generate boundary stresses great enough to erode streambeds composed of the Porters Creek Clay Formation. Therefore, assessing material resistance and location is essential in classifying and modelling streambed erosion processes of these streams.

  13. Frijolito Watershed: Integrated investigations of a rapidly eroding pinyon-juniper hillslope

    SciTech Connect

    Wilcox, B.P.; Pitlick, J.; Allen, C.D.

    1995-12-31

    The dramatic acceleration of erosion associated with the expansion of pinyon-juniper woodlands over the past 100 years has been widely recognized, but few process-based studies of this phenomenon have been undertaken. In an attempt to identify the underlying causes, and the factors that affect erosion processes, we have initiated an interdisciplinary study of a rapidly eroding pinyon-juniper woodland in northern New Mexico. Since July 1993, we have collected data on runoff, erosion, and weather conditions from a 1-ha catchment study area and have conducted surveys of topography, soils, and vegetation. Our preliminary results indicate that although runoff makes up less than 10% of the annual water budget, runoff events - which are frequent in the summer - are capable of moving large amounts of sediment. We estimate that between July 1993 and October 1994, between 25,000 and 50,000 kg of sediment has eroded and been transported from the catchment. The information gained from such studies is essential to our ability to formulate effective strategies for managing these rapidly eroding woodlands.

  14. Impacts of peatland restoration on dissolved carbon loss from eroded upland peatlands in the UK

    NASA Astrophysics Data System (ADS)

    Evans, M.; Stimson, A.; Allott, T. E. H. A.; Holland, N.

    2012-04-01

    Upland blanket peatlands in the UK are severely degraded by extensive gully erosion. Large areas have experienced complete vegetation loss. In the last decade landscape scale approaches to the restoration of eroded and bare peat have been developed in the Peak District National Park in northern England. Bare peat is re-vegetated with a nurse crop of grasses established by the aerial application of lime, seed, and fertiliser. The approach has successfully re-vegetated large areas of eroded bog a nd has been shown to dramatically reduce particulate carbon losses in runoff. The impacts of the treatment on water quality and dissolved carbon loss have not previously been fully assessed. This paper reports results from a small catchment study assessing the impacts of restoration practice in the Peak District. Data from five small catchments are presented one re-vegetated, one intact and three eroded/bare catchments. Bi-weekly water samples have been taken from the catchments between January 2011 and February 2012 and during July 2012 two of the bare sites were treated with lime, seed, and fertiliser. The data show that there are significant spikes in nutrient flux post treatment and marked effects on dissolved carbon which include initial spikes in in DOC concentration but longer term reductions in DOC concentration. Monitoring is ongoing at these sites but the evidence to date points to at least a short term benefit in DOC flux reduction from this form of peatland restoration.

  15. Element ratios between digestive gland and gill tissues of the Antarctic bivalve Laternula elliptica as a proxy for element uptake from different environmental sources

    NASA Astrophysics Data System (ADS)

    Poigner, H.; Monien, D.; Monien, P.; Kriews, M.; Brumsack, H.-J.; Wilhelms-Dick, D.; Abele, D.

    2012-04-01

    Trace metals in bivalve carbonate shells are frequently used as environmental or paleoclimate proxies. Carbonate mineralogy and animals' physiology affect the incorporation of elements from different environmental sources into bivalve shells. Generally, metals from particulate matter are assimilated via the digestive tract; whereas dissolved metals are absorbed via gills. Therefore, measurements of element concentrations deposited in the shell matrix do not necessarily allow inference with respect to the assimilation pathways. In this study, we used element ratios between digestive gland (DG) and gills (cDG/cGill) of the Circum-Antarctic clam Laternula elliptica to identify predominating assimilation pathways and potential sources of bio-available metals. This normalization between tissues of each individual eliminates the effects of individual age and physiological condition (e.g. accumulation over lifetime, metabolic activity) on metal assimilation. These effects also minimize the reproducibility, when absolute element concentrations are compared between individuals from different locations. Therefore, an additional normalization is required. We favored "ellipsoid shell volume" over shell length or soft tissue weight as more conservative approximation for intra- and intersite comparisons. Metal concentrations in DG, gills, and hemolymph of the bivalve L. elliptica, collected at Potter Cove (King George Island, Antarctic Peninsula), were analyzed by means of inductively coupled plasma - optical emission spectroscopy and mass spectrometry after total acid digestion. The element ratios (cDG/cGill) indicate a predominant assimilation of Al, Ca, Fe, K, Mn, and Mg from the dissolved phase. These high Al and Fe concentrations in gill tissues and hemolymph are in contrast to the low solubility of Al and Fe in seawater. But high dissolved Fe concentrations in pore waters (up to 1400 μg L-1 due to suboxic sediment conditions) and glacial melt waters enriched in dissolved

  16. Oxidative damage in gills and liver in Nile tilapia (Oreochromis niloticus) exposed to diazinon.

    PubMed

    Toledo-Ibarra, G A; Díaz Resendiz, K J G; Ventura-Ramón, G H; González-Jaime, F; Vega-López, A; Becerril-Villanueva, E; Pavón, L; Girón-Pérez, M I

    2016-10-01

    Agricultural activity demands the use of pesticides for plague control and extermination. In that matter, diazinon is one of the most widely used organophosphorus pesticides (OPs). Despite its benefits, the use of OPs in agricultural activities can also have negative effects since the excessive use of these substances can represent a major contamination problem for water bodies and organisms that inhabit them. The aim of this paper was to evaluate oxidative damage in lipids and proteins of Nile tilapia (Oreochromis niloticus) exposed acutely to diazinon (0.97, 1.95 and 3.95ppm) for 12 or 24h. The evaluation of oxidative damage was determined by quantifying lipid hydroperoxides (Fox method) and oxidized proteins (DNPH method). The data from this study suggest that diazinon induces a concentration-dependent oxidative damage in proteins, but not lipids, of the liver and gills of Nile tilapia. Furthermore, the treatment leads to a decrease in the concentration of total proteins, which can have serious consequences in cell physiology and fish development. PMID:27174646

  17. Oxidative stress, genotoxicity and histopathology biomarker responses in Mugil cephalus and Dicentrarchus labrax gill exposed to persistent pollutants. A field study in the Bizerte Lagoon: Tunisia.

    PubMed

    Ameur, Walid Ben; El Megdiche, Yassine; de Lapuente, Joaquin; Barhoumi, Badreddine; Trabelsi, Souad; Ennaceur, Soukaina; Camps, Lydia; Serret, Joan; Ramos-López, David; Gonzalez-Linares, Javier; Touil, Soufiane; Driss, Mohamed Ridha; Borràs, Miquel

    2015-09-01

    The use of biomarkers has become an important tool for modern environmental assessment as they can help to predict pollutants involved in the monitoring program. Despite the importance of fish gill in several functions (gaseous exchange, osmotic and ionic regulation, acid-base balance and nitrogenous waste) its use in coastal water biomonitoring focusing on protection and damage is scarce. This field study investigates biochemical (catalase, superoxide dismutase, lipid peroxidation), molecular (DNA integrity) and morphological (histology) parameters in gill of mullet (Mugil cephalus) and sea bass (Dicentrarchus labrax) and originating from Bizerte lagoon (a coastal lagoon impacted by different anthropogenic activities) and from the Mediterranean Sea (a reference site). Remarkable alterations in the activities of oxidative stress enzymes and DNA integrity in the tissue of the two studied fish species were detected in Bizerte Lagoon. The study of histopathological alterations of gills in both two fish species from Bizerte Lagoon suggest thickening of primary lamellae, cellular hyperplasia, aneurism, curving, shortening and fusion of secondary lamellae. The adopted approach, considering simultaneously protection responses and damaging effects, revealed its usefulness on the pollution assessment. PMID:25912422

  18. Insights into the mechanisms underlying mercury-induced oxidative stress in gills of wild fish (Liza aurata) combining (1)H NMR metabolomics and conventional biochemical assays.

    PubMed

    Cappello, Tiziana; Brandão, Fátima; Guilherme, Sofia; Santos, Maria Ana; Maisano, Maria; Mauceri, Angela; Canário, João; Pacheco, Mário; Pereira, Patrícia

    2016-04-01

    Oxidative stress has been described as a key pathway to initiate mercury (Hg) toxicity in fish. However, the mechanisms underlying Hg-induced oxidative stress in fish still need to be clarified. To this aim, environmental metabolomics in combination with a battery of conventional oxidative stress biomarkers were applied to the gills of golden grey mullet (Liza aurata) collected from Largo do Laranjo (LAR), a confined Hg contaminated area, and São Jacinto (SJ), selected as reference site (Aveiro Lagoon, Portugal). Higher accumulation of inorganic Hg and methylmercury was found in gills of fish from LAR relative to SJ. Nuclear magnetic resonance (NMR)-based metabolomics revealed changes in metabolites related to antioxidant protection, namely depletion of reduced glutathione (GSH) and its constituent amino acids, glutamate and glycine. The interference of Hg with the antioxidant protection of gills was corroborated through oxidative stress endpoints, namely the depletion of glutathione peroxidase and superoxide dismutase activities at LAR. The increase of total glutathione content (reduced glutathione+oxidized glutathione) at LAR, in parallel with GSH depletion aforementioned, indicates the occurrence of massive GSH oxidation under Hg stress, and an inability to carry out its regeneration (glutathione reductase activity was unaltered) or de novo synthesis. Nevertheless, the results suggest the occurrence of alternative mechanisms for preventing lipid peroxidative damage, which may be associated with the enhancement of membrane stabilization/repair processes resulting from depletion in the precursors of phosphatidylcholine (phosphocholine and glycerophosphocholine), as highlighted by NMR spectroscopy. However, the observed decrease in taurine may be attributable to alterations in the structure of cell membranes or interference in osmoregulatory processes. Overall, the novel concurrent use of metabolomics and conventional oxidative stress endpoints demonstrated to be

  19. Heavy metals distribution in muscle, liver, kidney and gill of European catfish (Silurus glanis) from Italian Rivers.

    PubMed

    Squadrone, S; Prearo, M; Brizio, P; Gavinelli, S; Pellegrino, M; Scanzio, T; Guarise, S; Benedetto, A; Abete, M C

    2013-01-01

    The accumulation of heavy metals in freshwaters has direct consequences to man and ecosystem. Thus, in this study, the concentrations of mercury, cadmium, lead, arsenic and chromium in organs of the predator European catfish (Silurus glanis) were investigated. Samples were collected annually in five sites covering the area of the Po River (North Italy) between 2007 and 2009. Metals were differently distributed in the various organs, the highest concentrations of Hg were found in muscle and liver, Cd in kidney, Pb in gill and liver, as in muscle, and of Cr in gill and liver. Our survey found Hg exceeding the Maximum Levels (MLs) of 0.5 ppm in 18% of samples, while Pb and Cd were lower than the MLs set by European regulations in muscle tissues (1881/2006/EC and 629/2008/EC). Hg concentrations were significantly related to sampling stations studied, according to the presence of many industrial activities in the catchment area of Bormida and Tanaro Rivers. The finding that Hg did not fit food fish legislation limits indicated that S. glanis flesh might not be utilised for human consumption. A close monitoring of metals pollution is strongly recommended especially in piscivorous fish, cause their bioaccumulation capacity. PMID:22901372

  20. Attachment ability of a clamp-bearing fish parasite, Diplozoon paradoxum (Monogenea), on gills of the common bream, Abramis brama.

    PubMed

    Wong, Wey-Lim; Gorb, Stanislav N

    2013-08-15

    Monogeneans, which are mainly fish ectoparasites, use various types of haptoral (posterior) attachment apparatus to secure their attachment onto their hosts. However, it remains unclear how strongly a monogenean can attach onto its host. In the present study, we aimed for the first time to (1) measure pull-off forces required to detach a pair of clamp-bearing monogeneans, Diplozoon paradoxum, from gills of Abramis brama and (2) determine the contribution of muscles to the clamp movements. A mean force of 6.1±2.7 mN (~246 times the animals' weight) was required to dislodge a paired D. paradoxum vertically from the gills. There were significant differences (P<0.05, Tukey test) between the widths of clamp openings in D. paradoxum treated in three different solutions: the widest clamp openings were observed in the monogeneans treated in 100 mmol l(-1) potassium chloride solution (58.26±13.44 μm), followed by those treated in 20 mmol l(-1) magnesium chloride solution (37.91±7.58 μm), and finally those treated in filtered lake water (20.16±8.63 μm). This suggests that the closing of the clamps is probably not due to the continuous contraction of extrinsic muscles but is caused by the elasticity of the clamp material and that muscle activity is required for clamp opening. PMID:23580722

  1. Simulation of acid-base condition and copper speciation in the fish gill microenvironment.

    PubMed

    Tao, S; Wen, Y; Long, A; Dawson, R; Cao, J; Xu, F

    2001-05-01

    pH, alkalinity, and mucus content in the fish gill microenvironment of carp (Cyprinus carpio) were measured by exposing fish to copper at various water pH levels using an apparatus which separates inspired and expired water. The relationship between pH levels inside and outside of the gill microenvironment, between pH and alkalinity, and between mucus secretion, pH, and copper exposure concentration were modeled. Copper speciation in the surrounding water and in the fish gill microenvironment was simulated using MINTEQA2 chemical equilibrium calculation software. The results of the modeling for pH, alkalinity, and mucus calculation were then adopted as inputs for purposes of parameter identification in the speciation modeling. The differences observed in the copper species distribution between that of the fish gill microenvironment and the surrounding water were based on the speciation modeling. The change in copper bioavailability for fish uptake was also examined. The results indicate the presence of an experimental pH balance point at 6.9, where the pH in the fish gill microenvironment is identical to that of the surrounding water. The observed deviation range in pH levels between that found at the gills and that of the surrounding water varied from -0.4 to 0.8 units. A sinusoidal model was developed for calculation of gill pH based on the pH of the surrounding water. Models calculating alkalinity either in the gill microenvironment or in the surrounding water and for estimating mucus secretion were also developed. The results of the chemical equilibrium calculations demonstrate that, within a pH range of 6-9, the dominant species of copper in bulk solution shifted from free ions to that of the hydroxo complex. With respect to the fish gill microenvironment, the dominant species found under acidic conditions were the mucus copper complex and free ions. Because of the influence of mucus complexation and pH change, bioavailable copper species in the fish gill

  2. Cohesive Sediment Erodibility and Evolution of a Mud Deposit on the Palos Verdes Shelf

    NASA Astrophysics Data System (ADS)

    Sherwood, C. R.; Ferre, B.; Murray, C. J.; Sanford, L. P.; Warner, J. C.; Wiberg, P. L.

    2006-12-01

    We have added a cohesive-sediment erodibility algorithm to ROMS, a three-dimensional numerical model for circulation and sediment transport. The new code implements an algorithm developed by Sanford ("Modeling a dynamically varying mixed sediment bed with erosion, deposition, bioturbation, consolidation, and armoring", Computers and Geosciences, in review.) The algorithm assumes that cohesive sediment has a critical stress for erosion that varies (typically increasing) with depth in the sediment, determined by various physical and biological properties or processes. Erosion and deposition alter this profile, but it is reestablished over a characteristic time scale which is longer than typical resuspension events (a few days) but probably less than a year. The critical stress profile limits the amount of sediment that can be eroded during to the mass available at the maximum stress applied during the event. Because the critical stress profile varies with time, the response to events depends on the history of sediment disturbance and recovery. The shapes of the critical stress profiles can vary both horizontally and vertically. In this pilot application, the shapes of the profiles were determined from geostatistical modeling of field data collected on a mud deposit on the Palos Verdes Shelf off Los Angeles. The data include about 30 traditional grain-size measurements, 10 erosion-chamber experiments, and 160 measurements of the penetration depths of a sediment-profiling camera. The penetration depths were highly correlated (r=0.84) with the slope of the erodibility profiles determined by the erosion chamber. Maps of erodibility (i.e., slope and offset of the critical stress profiles) on the Palos Verdes Shelf were made with Gaussian simulation and collocated cokriging of the erosion-chamber data conditioned on the camera-penetration data. These and maps of bottom grain-size distribution were used to initialize the bed sediment in ROMS. Model runs were made for the

  3. McPHAC: McGill Planar Hydrogen Atmosphere Code

    NASA Astrophysics Data System (ADS)

    Haakonsen, Christian Bernt; Turner, Monica L.; Tacik, Nick A.; Rutledge, Robert E.

    2012-10-01

    The McGill Planar Hydrogen Atmosphere Code (McPHAC) v1.1 calculates the hydrostatic equilibrium structure and emergent spectrum of an unmagnetized hydrogen atmosphere in the plane-parallel approximation at surface gravities appropriate for neutron stars. McPHAC incorporates several improvements over previous codes for which tabulated model spectra are available: (1) Thomson scattering is treated anisotropically, which is shown to result in a 0.2%-3% correction in the emergent spectral flux across the 0.1-5 keV passband; (2) the McPHAC source code is made available to the community, allowing it to be scrutinized and modified by other researchers wishing to study or extend its capabilities; and (3) the numerical uncertainty resulting from the discrete and iterative solution is studied as a function of photon energy, indicating that McPHAC is capable of producing spectra with numerical uncertainties <0.01%. The accuracy of the spectra may at present be limited to ~1%, but McPHAC enables researchers to study the impact of uncertain inputs and additional physical effects, thereby supporting future efforts to reduce those inaccuracies. Comparison of McPHAC results with spectra from one of the previous model atmosphere codes (NSA) shows agreement to lsim1% near the peaks of the emergent spectra. However, in the Wien tail a significant deficit of flux in the spectra of the previous model is revealed, determined to be due to the previous work not considering large enough optical depths at the highest photon frequencies. The deficit is most significant for spectra with T eff < 105.6 K, though even there it may not be of much practical importance for most observations.

  4. [Psychopathological study on Gilles de la Tourette's Syndrome].

    PubMed

    Suzuki, M

    1996-01-01

    Ten cases of Gilles de la Tourette's Syndrome (GTS) are reported. Average age of onset of the syndrome was 6.3 years old. Many of them were eldest children. 40% of them were caused by hereditary factor, and 40% of them had some abnormalities at their birth, for verbal tics including coprolalia. The GTS were classified into two types, Type I and Type II, from psychopathological point of view. Type I is "sadistic self-conversion type" and Type II is "masochistic personality type." Type I have an experience of attacks from others first, and, then, the desire of sadism aroused by the others converts to themselves after the others are abandoned from their mind, but it remains the stage of self-injurious. Principal mechanisms of Type I are "turning round the desire upon oneself" and "identification of oneself to the aggression." Type II have basically masochistic personality. They desire to be loved by others, but frustration that they feel they are not loved by others arouse the tic symptoms that violate the prohibition. With the tic symptoms, they can gain "punishment" and "pleasure" at the same time. Their symptoms of tics have the meaning of "masochistic provocation." They have the mechanism of "avoidance of anxiety by demanding to be loved by others." Both types have a common psychopathology, that is, they can not grasp objects (self or others) as a whole. It is suggested that patients with the GTS stopped their growth at pre-sexual stage. There exists a phase of self-injurious tics and that of other-injurious (provocately) tics during the progress of the symptoms of complex motor tics and verbal tics (coprolalia). The phase when both tics turn over each other was also observed. Echo-phenomena were seen only for patients of Type I. It is suggested that the degree of organic dysfunction of the brain and spectrum of masochism are almost coincident. PMID:8935828

  5. Genome scan for linkage to Gilles de la Tourette syndrome

    SciTech Connect

    Barr, C.L.; Livingston, J.; Williamson, R.

    1994-09-01

    Gilles de la Tourette Syndrome (TS) is a familial, neuropsychiatric disorder characterized by chronic, intermittent motor and vocal tics. In addition to tics, affected individuals frequently display symptoms such as attention-deficit hyperactivity disorder and/or obsessive compulsive disorder. Genetic analyses of family data have suggested that susceptibility to the disorder is most likely due to a single genetic locus with a dominant mode of transmission and reduced penetrance. In the search for genetic linkage for TS, we have collected well-characterized pedigrees with multiple affected individuals on whom extensive diagnostic evaluations have been done. The first stage of our study is to scan the genome systematically using a panel of uniformly spaced (10 to 20 cM), highly polymorphic, microsatellite markers on 5 families segregating TS. To date, 290 markers have been typed and 3,660 non-overlapping cM of the genome have been excluded for possible linkage under the assumption of genetic homogeneity. Because of the possibility of locus heterogeneity overall summed exclusion is not considered tantamount to absolute exclusion of a disease locus in that region. The results from each family are carefully evaluated and a positive lod score in a single family is followed up by typing closely linked markers. Linkage to TS was examined by two-point analysis using the following genetic model: single autosomal dominant gene with gene frequency .003 and maximum penetrance of .99. An age-of-onset correction is included using a linear function increasing from age 2 years to 21 years. A small rate of phenocopies is also incorporated into the model. Only individuals with TS or CMT according to DSM III-R criteria were regarded as affected for the purposes of this summary. Additional markers are being tested to provide coverage at 5 cM intervals. Moreover, we are currently analyzing the data non-parametrically using the Affected-Pedigree-Member Method of linkage analysis.

  6. Soil aggregates, organic matter turnover and carbon balance in a Mediterranean eroded vineyard

    NASA Astrophysics Data System (ADS)

    Novara, Agata; Lo Papa, Giuseppe; Dazzi, Carmelo; Gristina, Luciano; Cerdà, Artemi

    2014-05-01

    The carbon cycle is being affected by the human impacts (Novara et al., 2011; Yan-Gui et al., 2013), and one of those is the intensification in the soil erosion in agriculture land (Cerdà et al., 2009; García Orenes et al., 2009). Vineyards also are affected by the human activities (Fernández Calviño, 2012). Vineyards in Sicily are cultivated on 110.000 ha, 10% of which on >10% slope. Deficiencies of soil organic matter are typical of the semi arid Mediterranean environment especially where traditional intensive cropping practices are adopted (Novara et al., 2012; 2013). These practices in vineyards could lead soil to intensive erosion processes (Novara et al., 2011). The fate of SOC under erosion processes is difficult to understand because of the influence of the erosion impact on SOC pathway, which depends on the different features of the process involved (detachment, transport and/or deposition). Soil erosion must be considered a net C source (Lal, 2003), as eroded soils have lower net primary productivity (NPP) (Dick and Gregorich, 2004) caused by reduction in the effective rooting depth and all in all determining decline in soil quality. Breakdown of aggregates and soil dispersion expose SOM to microbial/enzymatic processes and chemical soil properties (Dimoyiannis, 2012; Kocyigit and Demirci, 2012). Moreover the light fraction, transported by runoff, is labile and easily mineralized determining CO2 emission in the atmosphere (Jacinthe and Lal, 2004). Therefore, the carbon pool is lower in eroded than in un-eroded soil scapes and the rate of mineralization of soil organic matter is higher in sediments than in original soil. In this survey we show a research conducted on a slope sequence of three soil profiles in an irrigated vineyard located in Sambuca di Sicilia, Italy (UTM33-WGS84: 4169367N; 325011E). The SOC content was measured at depth intervals of 10 cm up to a depth of 60 cm in each pedon. Wet aggregate-size fractions with no prior chemical

  7. Natural Mineral Particles Are Cytotoxic to Rainbow Trout Gill Epithelial Cells In Vitro

    PubMed Central

    de Capitani, Christian; Burkhardt-Holm, Patricia; Pietsch, Constanze

    2014-01-01

    Worldwide increases in fluvial fine sediment are a threat to aquatic animal health. Fluvial fine sediment is always a mixture of particles whose mineralogical composition differs depending on the sediment source and catchment area geology. Nonetheless, whether particle impact in aquatic organisms differs between mineral species remains to be investigated. This study applied an in vitro approach to evaluate cytotoxicity and uptake of four common fluvial mineral particles (quartz, feldspar, mica, and kaolin; concentrations: 10, 50, 250 mg L−1) in the rainbow trout epithelial gill cell line RTgill-W1. Cells were exposed for 24, 48, 72, and 96 h. Cytotoxicity assays for cell membrane integrity (propidium iodide assay), oxidative stress (H2DCF-DA assay), and metabolic activity (MTT assay) were applied. These assays were complemented with cell counts and transmission electron microscopy. Regardless of mineral species, particles ≤2 µm in diameter were taken up by the cells, suggesting that particles of all mineral species came into contact and interacted with the cells. Not all particles, however, caused strong cytotoxicity: Among all assays the tectosilicates quartz and feldspar caused sporadic maximum changes of 0.8–1.2-fold compared to controls. In contrast, cytotoxicity of the clay particles was distinctly stronger and even differed between the two particle types: mica induced concentration-dependent increases in free radicals, with consistent 1.6–1.8-fold-changes at the 250 mg L−1 concentration, and a dilated endoplasmic reticulum. Kaolin caused concentration-dependent increases in cell membrane damage, with consistent 1.3–1.6-fold increases at the 250 mg L−1 concentration. All effects occurred in the presence or absence of 10% fetal bovine serum. Cell numbers per se were marginally affected. Results indicate that (i.) natural mineral particles can be cytotoxic to gill epithelial cells, (ii.) their cytotoxic potential differs between mineral species

  8. In vitro effect of various xenobiotics on trout gill cell volume regulation after hypotonic shock.

    PubMed

    Leguen, I; Prunet, P

    2001-08-01

    Their functions and localisation can expose gill cells to volume changes. To maintain their vital functions, these gill cells must regulate their own volume after cellular swelling or shrinkage. Recently, we showed that rainbow trout pavement gill cells in primary culture have the capacity to regulate their own volume after cellular swelling induced by hypotonic shock. This so-called regulatory volume decrease (RVD) is associated with intracellular calcium increase, which occurs as a transient peak followed by a plateau when maintained a hypotonic condition. Return to an isotonic medium restores baseline [Ca2+]i level. In this study, the effect of different xenobiotics on cellular swelling induced RVD and its calcium signal was investigated in trout pavement gill cells in primary culture. These cells were exposed to different pollutants after confluent epithelium was obtained. After 36 h in xenobiotics exposure in vitro, cellular volume and intracellular calcium concentration were measured. Nonylphenol poly- and di-ethoxylate were lethal at concentrations of 10 and 100 microM, respectively. With 10 microM of the diethoxylate form, cells did not die but, unlike non-treated cells, burst during hypotonic shock (2/3rd strength Ringer solution). With 1 microM nonylphenol polyethoxylate (NPnEO), RVD and [Ca2+]i were reduced. Copper (10 and 100 microM) had no significant effect on gill cell volume regulation. However, the heavy metal modified calcium response to hypotonic shock by inhibiting return to baseline level under isotonic conditions. 10 microM prochloraz and 2,4-dichloroaniline had no effect on cell morphology, volume and [Ca2+]i concentration. With 100 microM, however, prochloraz was lethal and dichloroaniline increased baseline [Ca2+]i. These results indicate that the effects observed on gill cells are consistent with the known toxic properties of the molecules tested, thus confirming the validity of primary culture to investigate the toxic effects of

  9. Gill Morphology and Oxygen Diffusion Distance in Juvenile Striped Killifish, Fundulus majalis

    NASA Astrophysics Data System (ADS)

    McEnroe, M.; Rivera, L.; La Fortune, B.; Miller, A.

    2010-12-01

    Striped killifish (Fundulus majalis) are an important estuarine forage fish. Larvae and juveniles utilize shallow marsh pools which become warm (>30 C) and hypoxic (DO < 2mg/l) in summer. To investigate potential morphological adaptations to this environment we studied gill morphology. Gill surface area (GSA) and oxygen diffusion distance are important parameters for oxygen uptake, as expressed by Fick's Equation for diffusion. To measure these parameters fish (N=20, 20-50 mm TL) were collected from marsh pools and adjacent Long Island Sound in late summer, weighed, and measured. The gills were fixed in Karnovsky’s solution. For scanning electron microscopy (SEM) they were rinsed, dehydrated in a graded ETOH series, and critically point dried, sputter-coated and were observed with ISR-SR-50 SEM. Gill morphology (number of filaments, filament length, lamellar density, and lamellar size) were quantified using SEM. Total gill surface area (GSA) was calculated using the method of Hughes (1984); GSA = L* n* bl where L = sum of filament lengths, n = number of lamellae/mm, and bl = bilateral lamellar surface area. To measure oxygen diffusion distance from water to blood, samples were embedded in Araldite 502/Embed 812 TM plastic medium for transmission electron microscopy (TEM). Stained (uranyl acetate and calcinated lead citrate) thin sections were examined using a FEI/Philips Morgagni 268 transmission electron microscope (TEM). Gill lamellar diffusion distance was measured using the technique of Matey et al., 2008 and found to be low (1.0 µm ± 0.4; mean ± SD; N= 17). Gill structure and oxygen diffusion distance will be compared to other fishes from normoxic and hypoxic environments.

  10. Alterations in gill structure in tropical reef fishes as a result of elevated temperatures.

    PubMed

    Bowden, A J; Gardiner, N M; Couturier, C S; Stecyk, J A W; Nilsson, G E; Munday, P L; Rummer, J L

    2014-09-01

    Tropical regions are expected to be some of the most affected by rising sea surface temperatures (SSTs) because seasonal temperature variations are minimal. As temperatures rise, less oxygen dissolves in water, but metabolic requirements of fish and thus, the demand for effective oxygen uptake, increase. Gill remodelling is an acclimation strategy well documented in freshwater cyprinids experiencing large seasonal variations in temperature and oxygen as well as an amphibious killifish upon air exposure. However, no study has investigated whether tropical reef fishes remodel their gills to allow for increased oxygen demands at elevated temperatures. We tested for gill remodelling in five coral reef species (Acanthochromis polyacanthus, Chromis atripectoralis, Pomacentrus moluccensis, Dascyllus melanurus and Cheilodipterus quinquelineatus) from populations in northern Papua New Guinea (2° 35.765' S; 150° 46.193' E). Fishes were acclimated for 12-14 days to 29 and 31°C (representing their seasonal range) and 33 and 34°C to account for end-of-century predicted temperatures. We measured lamellar perimeter, cross-sectional area, base thickness, and length for five filaments on the 2nd gill arches and qualitatively assessed 3rd gill arches via scanning electron microscopy (SEM). All species exhibited significant differences in the quantitative measurements made on the lamellae, but no consistent trends with temperature were observed. SEM only revealed alterations in gill morphology in P. moluccensis. The overall lack of changes in gill morphology with increasing temperature suggests that these near-equatorial reef fishes may fail to maintain adequate O2 uptake under future climate scenarios unless other adaptive mechanisms are employed. PMID:24862962

  11. The toxicological impacts of some heavy metals on carbonic anhydrase from gilthead sea bream (Sparus aurata) gills.

    PubMed

    Kaya, Elif Duygu; Söyüt, Hakan; Beydemir, Şükrü

    2015-03-01

    It is known that heavy metals have toxic effects on fish. Insufficient measures are a serious problem in our country and around the world. This problem can threaten human health in areas where it is common for people to obtain nutrition from local bodies of water. In this study, the toxicological impacts of some heavy metals were investigated on carbonic anhydrase activity in gilthead gills. Carbonic anhydrase (CA) was purified from gilthead sea bream (Sparus aurata) gills with a specific activity of 2872.92 EU mg(-1) and a yield of 32.84% using affinity chromatography. The overall purification was approximately ∼ 84-fold. SDS-polyacrylamide gel electrophoresis showed a single band, and the MW was approximately 30.5 kDa (Soyut et al., 2008, 2012; Soyut and Beydemir, 2008, 2012; Kaya et al., 2013). The kinetic and characteristic properties of CA such as the optimum pH, stable pH, optimum temperature, activation energy (Ea), activation enthalpy (ΔH), Q10, Km and Vmax were determined. Cadmium (Cd(2+)), copper (Cu(2+)), nickel (Ni(2+)) and silver (Ag(+)) inhibited CA activity in in vitro conditions. Ki values were calculated for these metals. Ki values were 31.20mM for cadmium (Cd(2+)), 161.96 mM for copper (Cu(2+)), 10.79 mM for nickel (Ni(2+)) and 0.0082 mM for silver (Ag(+)) based on Lineweaver-Burk plots. Except for cadmium, heavy metals had the same inhibition mechanism. Cadmium was competitive, and the others were noncompetitive. PMID:25769102

  12. Impact of detergents on the protein histochemistry of various cell types of the gill epithelium of Rita rita.

    PubMed

    Roy, D

    1988-04-01

    Fish, Rita rita, were exposed to an anionic detergent, dodecylbenzene sodium sulfonate, 6.9 mg per litre of tap water (96-hr LC50 of the detergent). A gradual decrease in the protein constituents of the major cell types, viz, the epithelial cells and the goblet mucous cells in the epithelium lining the gill arch, gill filament, and club cells present only in the gill arch epithelium has been observed by using a series of histochemical techniques. PMID:3378537

  13. In vivo exposure of the marine clam Ruditapes philippinarum to zinc oxide nanoparticles: responses in gills, digestive gland and haemolymph.

    PubMed

    Marisa, Ilaria; Matozzo, Valerio; Munari, Marco; Binelli, Andrea; Parolini, Marco; Martucci, Alessandro; Franceschinis, Erica; Brianese, Nicola; Marin, Maria Gabriella

    2016-08-01

    Potential nanoparticle (NP) toxicity poses a growing concern in marine coastal environments. Among NPs, zinc oxide nanoparticles (nZnO) are widely used in many common products that ultimately become deposited in coastal habitats from multiple non-point sources. In this study, we evaluated the in vivo effects of nZnO in the clam Ruditapes philippinarum. Animals were exposed to nZnO (1 and 10 μg/L) and ZnCl2 (10 μg/L) for 7 days. ZnCl2 was used to compare the effects of the NPs to those of Zn(2+) and to ascertain whether nZnO toxicity is attributable to the release of ions into the aquatic medium. At differing time intervals during the exposure, several biochemical and cellular responses were evaluated in the clam gills, digestive gland, and haemolymph. The results showed that nZnO, at concentrations close to the predicted environmental levels, significantly affected various parameters in clam tissues. Significant increases in catalase and superoxide dismutase activities and a decreasing trend of glutathione S-transferase activity indicated the involvement of oxidative stress in nZnO toxicity. In clams exposed to ZnCl2, slight variations in antioxidant enzyme activities were detected with respect to nZnO-treated clams. However, no damage to lipids, proteins or DNA was revealed in all exposure conditions, suggesting a protection of antioxidant enzymes in the tissues. Of the various haemolymph parameters measured, haemocyte proliferation increased significantly, in ZnCl2-treated clams in particular. Under nZnO (10 μg/L) and ZnCl2 exposure, DNA damage in haemocytes was also revealed, but it was lower in clams exposed to ZnCl2. A decreasing trend in gill AChE activity of treated clams proposed a possible role of zinc ions in nZnO toxicity. However, the dissimilar modulation of the responses in the nZnO- and ZnCl2-exposed clams suggested different mechanisms of action, with nZnO toxicity possibly depending not only on the release of zinc ions but also on NP

  14. Characterization of angiotensin I-converting enzyme from anterior gills of the mangrove crab Ucides cordatus.

    PubMed

    Bersanetti, Patrícia A; Nogueira, Regina F; Marcondes, Marcelo F; Paiva, Paulo B; Juliano, Maria A; Juliano, Luiz; Carmona, Adriana K; Zanotto, Flavia P

    2015-03-01

    Angiotensin I-converting enzyme (ACE) is a well-known metallopeptidase that is found in vertebrates, invertebrates and bacteria. We isolated from the anterior gill of the crab Ucides cordatus an isoform of ACE, here named crab-ACE, which presented catalytic properties closely resembling to those of mammalian ACE. The enzyme was purified on Sepharose-lisinopril affinity chromatography to apparent homogeneity and a band of about 72 kDa could be visualized after silver staining and Western blotting. Assays performed with fluorescence resonance energy transfer (FRET) selective ACE substrates Abz-FRK(Dnp)P-OH, Abz-SDK(Dnp)P-OH and Abz-LFK(Dnp)-OH, allowed us to verify that crab-ACE has hydrolytic profile very similar to that of the ACE C-domain. In addition, we observed that crab-ACE can hydrolyze the ACE substrates, angiotensin I and bradykinin. The enzyme was strongly inhibited by the specific ACE inhibitor lisinopril (Ki of 1.26 nM). However, in contrast to other ACE isoforms, crab-ACE presented a very particular optimum pH, being the substrate Abz-FRK(Dnp)-P-OH hydrolyzed efficiently at pH 9.5. Other interesting characteristic of crab-ACE was that the maximum hydrolytic activity was reached at around 45°C. The description of an ACE isoform in Ucides cordatus is challenging and may contribute to a better understanding of the biochemical function of this enzyme in invertebrates. PMID:25544039

  15. DNA Damage and Transcriptional Changes in the Gills of Mytilus galloprovincialis Exposed to Nanomolar Doses of Combined Metal Salts (Cd, Cu, Hg)

    PubMed Central

    Varotto, Laura; Domeneghetti, Stefania; Rosani, Umberto; Manfrin, Chiara; Cajaraville, Miren P.; Raccanelli, Stefano; Pallavicini, Alberto; Venier, Paola

    2013-01-01

    Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarkers in parallel. Focusing on the mussel gills, first target of toxic water contaminants and actively proliferating tissue, we detected significant dose-related increases of cells with micronuclei and other nuclear abnormalities in the treated mussels, with differences in the bioconcentration of the three metals determined in the mussel flesh by atomic absorption spectrometry. Gene expression profiles, determined in the same individual gills in parallel, revealed some transcriptional changes at the 50 nM dose, and substantial increases of differentially expressed genes at the 100 and 200 nM doses, with roughly similar amounts of up- and down-regulated genes. The functional annotation of gill transcripts with consistent expression trends and significantly altered at least in one dose point disclosed the complexity of the induced cell response. The most evident transcriptional changes concerned protein synthesis and turnover, ion homeostasis, cell cycle regulation and apoptosis, and intracellular trafficking (transcript sequences denoting heat shock proteins, metal binding thioneins, sequestosome 1 and proteasome subunits, and GADD45 exemplify up-regulated genes while transcript sequences denoting actin, tubulins and the apoptosis inhibitor 1 exemplify down-regulated genes). Overall, nanomolar doses of co-occurring free metal ions have induced significant structural and functional changes in the mussel gills: the intensity of response to the stimulus measured in laboratory supports the additional validation of molecular markers of metal exposure to be used in Mussel Watch programs. PMID:23355883

  16. A Stenohaline Medaka, Oryzias woworae, Increases Expression of Gill Na(+), K(+)-ATPase and Na(+), K(+), 2Cl(-) Cotransporter 1 to Tolerate Osmotic Stress.

    PubMed

    Juo, Jiun-Jang; Kang, Chao-Kai; Yang, Wen-Kai; Yang, Shu-Yuan; Lee, Tsung-Han

    2016-08-01

    The present study aimed to evaluate the osmoregulatory mechanism of Daisy's medaka, O. woworae,as well as demonstrate the major factors affecting the hypo-osmoregulatory characteristics of euryhaline and stenohaline medaka. The medaka phylogenetic tree indicates that Daisy's medaka belongs to the celebensis species group. The salinity tolerance of Daisy's medaka was assessed. Our findings revealed that 20‰ (hypertonic) saltwater (SW) was lethal to Daisy's medaka. However, 62.5% of individuals survived 10‰ (isotonic) SW with pre-acclimation to 5‰ SW for one week. This transfer regime, "Experimental (Exp.) 10‰ SW", was used in the following experiments. After 10‰ SW-transfer, the plasma osmolality of Daisy's medaka significantly increased. The protein abundance and distribution of branchial Na(+), K(+)-ATPase (NKA) and Na(+), K(+), 2Cl(-) cotransporter 1 (NKCC1) were also examined after transfer to 10‰ SW for one week. Gill NKA activity increased significantly after transfer to 10‰ SW. Meanwhile, elevation of gill NKA αα-subunit protein-abundance was found in the 10‰ SW-acclimated fish. In gill cross-sections, more and larger NKA-immunoreactive (NKA-IR) cells were observed in the Exp. 10‰ SW medaka. The relative abundance of branchial NKCC1 protein increased significantly after transfer to 10‰ SW. NKCC1 was distributed in the basolateral membrane of NKA-IR cells of the Exp. 10‰ SW group. Furthermore, a higher abundance of NKCC1 protein was found in the gill homogenates of the euryhaline medaka, O. dancena, than in that of the stenohaline medaka, O. woworae. PMID:27498801

  17. DNA damage and transcriptional changes in the gills of mytilus galloprovincialis exposed to nanomolar doses of combined metal salts (Cd, Cu, Hg).

    PubMed

    Varotto, Laura; Domeneghetti, Stefania; Rosani, Umberto; Manfrin, Chiara; Cajaraville, Miren P; Raccanelli, Stefano; Pallavicini, Alberto; Venier, Paola

    2013-01-01

    Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarkers in parallel. Focusing on the mussel gills, first target of toxic water contaminants and actively proliferating tissue, we detected significant dose-related increases of cells with micronuclei and other nuclear abnormalities in the treated mussels, with differences in the bioconcentration of the three metals determined in the mussel flesh by atomic absorption spectrometry. Gene expression profiles, determined in the same individual gills in parallel, revealed some transcriptional changes at the 50 nM dose, and substantial increases of differentially expressed genes at the 100 and 200 nM doses, with roughly similar amounts of up- and down-regulated genes. The functional annotation of gill transcripts with consistent expression trends and significantly altered at least in one dose point disclosed the complexity of the induced cell response. The most evident transcriptional changes concerned protein synthesis and turnover, ion homeostasis, cell cycle regulation and apoptosis, and intracellular trafficking (transcript sequences denoting heat shock proteins, metal binding thioneins, sequestosome 1 and proteasome subunits, and GADD45 exemplify up-regulated genes while transcript sequences denoting actin, tubulins and the apoptosis inhibitor 1 exemplify down-regulated genes). Overall, nanomolar doses of co-occurring free metal ions have induced significant structural and functional changes in the mussel gills: the intensity of response to the stimulus measured in laboratory supports the additional validation of molecular markers of metal exposure to be used in Mussel Watch programs. PMID:23355883

  18. Altered structural connectivity of cortico-striato-pallido-thalamic networks in Gilles de la Tourette syndrome

    PubMed Central

    Marrakchi-Kacem, Linda; Lecomte, Sophie; Valabregue, Romain; Poupon, Fabrice; Guevara, Pamela; Tucholka, Alan; Mangin, Jean-François; Vidailhet, Marie; Lehericy, Stephane; Hartmann, Andreas; Poupon, Cyril

    2015-01-01

    Gilles de la Tourette syndrome is a childhood-onset syndrome characterized by the presence and persistence of motor and vocal tics. A dysfunction of cortico-striato-pallido-thalamo-cortical networks in this syndrome has been supported by convergent data from neuro-pathological, electrophysiological as well as structural and functional neuroimaging studies. Here, we addressed the question of structural integration of cortico-striato-pallido-thalamo-cortical networks in Gilles de la Tourette syndrome. We specifically tested the hypothesis that deviant brain development in Gilles de la Tourette syndrome could affect structural connectivity within the input and output basal ganglia structures and thalamus. To this aim, we acquired data on 49 adult patients and 28 gender and age-matched control subjects on a 3 T magnetic resonance imaging scanner. We used and further implemented streamline probabilistic tractography algorithms that allowed us to quantify the structural integration of cortico-striato-pallido-thalamo-cortical networks. To further investigate the microstructure of white matter in patients with Gilles de la Tourette syndrome, we also evaluated fractional anisotropy and radial diffusivity in these pathways, which are both sensitive to axonal package and to myelin ensheathment. In patients with Gilles de la Tourette syndrome compared to control subjects, we found white matter abnormalities in neuronal pathways connecting the cerebral cortex, the basal ganglia and the thalamus. Specifically, striatum and thalamus had abnormally enhanced structural connectivity with primary motor and sensory cortices, as well as paracentral lobule, supplementary motor area and parietal cortices. This enhanced connectivity of motor cortex positively correlated with severity of tics measured by the Yale Global Tics Severity Scale and was not influenced by current medication status, age or gender of patients. Independently of the severity of tics, lateral and medial orbito

  19. Hagfish: Champions of CO2 tolerance question the origins of vertebrate gill function

    PubMed Central

    Baker, Daniel W.; Sardella, Brian; Rummer, Jodie L.; Sackville, Michael; Brauner, Colin J.

    2015-01-01

    The gill is widely accepted to have played a key role in the adaptive radiation of early vertebrates by supplanting the skin as the dominant site of gas exchange. However, in the most basal extant craniates, the hagfishes, gills play only a minor role in gas exchange. In contrast, we found hagfish gills to be associated with a tremendous capacity for acid-base regulation. Indeed, Pacific hagfish exposed acutely to severe sustained hypercarbia tolerated among the most severe blood acidoses ever reported (1.2 pH unit reduction) and subsequently exhibited the greatest degree of acid-base compensation ever observed in an aquatic chordate. This was accomplished through an unprecedented increase in plasma [HCO3−] (>75 mM) in exchange for [Cl−]. We thus propose that the first physiological function of the ancestral gill was acid-base regulation, and that the gill was later co-opted for its central role in gas exchange in more derived aquatic vertebrates. PMID:26057989

  20. Effects of gill-net trauma, barotrauma, and deep release on postrelease mortality of Lake Trout

    USGS Publications Warehouse

    Ng, Elizabeth L.; Fredericks, Jim P.; Quist, Michael C.

    2015-01-01

    Unaccounted postrelease mortality violates assumptions of many fisheries studies, thereby biasing parameter estimates and reducing efficiency. We evaluated effects of gill-net trauma, barotrauma, and deep-release treatment on postrelease mortality of lake trout Salvelinus namaycush. Lake trout were captured at depths up to 65 m with gill nets in Priest Lake, Idaho, and held in a large enclosure for 10–12 d. Postrelease mortality was the same for surface-release–and deep-release–treated fish (41%). Mixed-effects logistic regression models were used to evaluate effects of intrinsic and environmental factors on the probability of mortality. Presence of gill-net trauma and degree of barotrauma were associated with increased probability of postrelease mortality. Smaller fish were also more likely to suffer postrelease mortality. On average, deep-release treatment did not reduce postrelease mortality, but effectiveness of treatment increased with fish length. Of the environmental factors evaluated, only elapsed time between lifting the first and last anchors of a gill-net gang (i.e., lift time) was significantly related to postrelease mortality. Longer lift times, which may allow ascending lake trout to acclimate to depressurization, were associated with lower postrelease mortality rates. Our study suggests that postrelease mortality may be higher than previously assumed for lake trout because mortality continues after 48 h. In future studies, postrelease mortality could be reduced by increasing gill-net lift times and increasing mesh size used to increase length of fish captured.

  1. Gills of hydrothermal vent annelids: Structure, ultrastructure and functional implications in two alvinellid species

    NASA Astrophysics Data System (ADS)

    Jouin, Claude; Gaill, Françoise

    The anatomy, fine structure, diffusion distances and respiratory surface areas of the gills of two species of the polychaete family Alvinellidae have been investigated. Each gill consists of a stem on which are inserted two opposite rows of respiratory elements: flat sickle-shaped lamellae in Alvinella pompejana and cylindrical filaments in Paralvinella grasslei. Both lamellae and filaments have a ciliated mucous epidermis, a central layer of supporting and muscle cells and are devoid of coelomic cavity. Each respiratory element possesses one afferent and one efferent marginal vessel, united to each other distally, and connected proximally to separate longitudinal vessels running in the stem. Superficial parallel blood spaces connect the marginal vessels across the lamella or filament. Deeper, between the basal laminae of the epidermis and that of the central cell layer, a blood sinus is also present. The marginal vessels and the superficial blood spaces actually are intraepidermal extensions of this deep blood sinus. The diffusion distances are very small owing to the intraepidermal position of the respiratory blood spaces. The specific gill surface areas in A. pompejana and P. grasslei are the largest known today in polychaetes, respectively 12 and 47 cm 2 per g wet weight. The distinctive features of the gills are possibly related to a low oxygen content of the ambient seawater. Numerous crystalline granules scattered in the gill epidermis suggest that this epithelium has a detoxifying function.

  2. Experimental induction of gill disease in Atlantic salmon Salmo salar smolts with Tenacibaculum maritimum.

    PubMed

    Powell, Mark; Carson, Jeremy; van Gelderen, Rebecca

    2004-11-01

    An experimentally induced bacterial infection of marine Atlantic salmon Salmo salar smolt gills was developed using strains of Tenacibaculum maritimum originally isolated from disease outbreaks in Tasmania. The gills of salmon were inoculated with a high concentration of bacteria (4 x 10(11) cells per fish) of either strain 00/3280 or 89/4747 T. maritimum. Gentle abrasion of the gills was used to enhance the progression of gill disease. One strain (00/3280) was highly pathogenic, causing morbidity and mortality within 24 h post-inoculation, and produced acute focal branchial necrosis associated with significant increases in plasma osmolality and lactate concentration compared with controls (non-inoculated) or strain 89/4747-inoculated fish. There were no differences in the whole body net ammonium flux between control (non-inoculated) and strain 00/3820-inoculated fish. Gill abrasion resulted in acute telangiectasis and focal lamellar hyperplasia in all fish regardless of bacterial inoculation. This work provides the basis of a challenge model suitable for investigating the pathophysiological processes associated with acute branchial necrosis in marine fish, suggesting that osmoregulatory and possibly respiratory dysfunction are the primary consequences of infection. PMID:15609873

  3. Prolactin regulates transcription of the ion uptake Na+/Cl− cotransporter (ncc) gene in zebrafish gill

    PubMed Central

    Breves, Jason P.; Serizier, Sandy B.; Goffin, Vincent; McCormick, Stephen D.; Karlstrom, Rolf O.

    2013-01-01

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na+/Cl− cotransporter (ncc; slc12a10.2), Na+/H+ exchanger (nhe3b; slc9a3.2), and epithelial Ca2+ channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl− uptake in zebrafish for the first time. PMID:23395804

  4. Prolactin regulates transcription of the ion uptake Na+/Cl- cotransporter (ncc) gene in zebrafish gill

    USGS Publications Warehouse

    Breves, Jason P.; Serizier, Sandy B.; Goffin, Vincent; McCormick, Stephen D.; Karlstrom, Rolf O.

    2013-01-01

    Prolactin (PRL) is a well-known regulator of ion and water transport within osmoregulatory tissues across vertebrate species, yet how PRL acts on some of its target tissues remains poorly understood. Using zebrafish as a model, we show that ionocytes in the gill directly respond to systemic PRL to regulate mechanisms of ion uptake. Ion-poor conditions led to increases in the expression of PRL receptor (prlra), Na+/Cl− cotransporter (ncc; slc12a10.2), Na+/H+ exchanger (nhe3b; slc9a3.2), and epithelial Ca2+ channel (ecac; trpv6) transcripts within the gill. Intraperitoneal injection of ovine PRL (oPRL) increased ncc and prlra transcripts, but did not affect nhe3b or ecac. Consistent with direct PRL action in the gill, addition of oPRL to cultured gill filaments stimulated ncc in a concentration-dependent manner, an effect blocked by a pure human PRL receptor antagonist (Δ1-9-G129R-hPRL). These results suggest that PRL signaling through PRL receptors in the gill regulates the expression of ncc, thereby linking this pituitary hormone with an effector of Cl− uptake in zebrafish for the first time.

  5. Gill histopathology of Maria-da-toca Hypleurochilus fissicornis by metacercariae of Bucephalus margaritae (Digenea: Bucephalidae).

    PubMed

    Silva, Renato Z; da Costa Marchiori, Natalia; Magalhães, Aimê Rachel M; Cousin, João Carlos B; Romano, Luis Alberto; Pereira, Joaber

    2016-06-01

    Gills of Maria-da-toca Hypleurochilus fissicornis collected at Ponta do Sambaqui-Florianópolis island-Brazil, were analyzed to describe the histopathology caused by metacercaria of Bucephalus margaritae. Gills were submitted to the routine histological techniques for embedding in paraffin and permanent mounting in Balsam and stereoscopic analysis. Metacercariae showed a branchial infection site pattern for encystations. The branchial infection site pattern is half-basalward in the primary branchial filament with amplitude of the infection of 1-3 metacercaria. Cysts occurred within branchial abductor muscle and cartilaginous and osseous tissues of the gills. Each metacercariae had a contentional hyaline parasitic capsule and melanin-like pigmentation. The half-apicalward region of the primary branchial filaments showed several dysplasia degrees, cartilage and osseous degeneration (pyknosis), thrombosis and immune exudated cells (mainly lymphocytes). Cytopathologies as thickening of the epithelium lining of the secondary branchial filaments were a response of the branchial infection site pattern of the metacercaria. Interlamellar obliteration and fusion of the lamellae due to the hypertrophy and hyperplasia of the epithelial lining as well as chloride cells occurred. Pyknosis of pillar cells and epithelial lining cells from the secondary branchial filaments were also present. Bucephalosis in H. fissicornis gills is no-hemorrhagic and no-fatal branchitis, but could compromises the gill functions and could permits the secondary opportunistic infections. PMID:27413297

  6. The Gilles de la Tourette syndrome: the current status.

    PubMed

    Robertson, Mary May

    2012-10-01

    Gilles de la Tourette syndrome (GTS) is characterised by multiple motor and one or more vocal/phonic tics. GTS was once thought to be rare, but many relatively recent studies suggest that the prevalence is about 1% of the worldwide community, apart from in Sub-Saharan Black Africa. Comorbidity and coexistent psychopathology are common, occurring in about 90% of clinical cohorts and individuals in the community. The most common comorbidities are attention deficit hyperactivity disorder, obsessive-compulsive behaviours, and disorder, and autistic spectrum disorders, while the most common coexisting psychopathologies are depression, anxiety and behavioural disorders such as oppositional defiant and conduct disorder. There has been an increasing amount of evidence to show that the quality of life in young people is reduced when compared with normative data or healthy control populations. It is widely accepted that most cases of GTS are inherited, but the genetic mechanisms appear much more complex than previously understood, as evidenced by many recent studies; indeed, there have been suggestions of 'general neurodevelopmental genes' which affect the brain development after which the 'specific GTS gene(s)' may further affect the phenotype. Other aetiopathogenetic suggestions have included environmental factors such as neuro-immunological factors, infections, prenatal and peri-natal difficulties and androgen influences. Few studies have addressed aetiology and phenotype, but initial results are exciting. The search for endophenotypes has followed subsequently. Intriguing neuroanatomical and brain circuitry abnormalities have now been suggested in GTS; the most evidence is for cortical thinning and a reduction in the size of the caudate nucleus. Thorough assessment is imperative and multidisciplinary management is the ideal. Treatment should be 'symptom targeted', and in mild cases, psycho-education and reassurance for the patient and the family may be sufficient

  7. Chemical transfers along slowly eroding catenas developed on granitic cratons in southern Africa

    USGS Publications Warehouse

    Khomo, Lesego; Bern, Carleton R.; Hartshorn, Anthony S.; Rogers, Kevin H.; Chadwick, Oliver A.

    2013-01-01

    A catena is a series of distinct but co-evolving soils arrayed along a slope. On low-slope, slowly eroding catenas the redistribution of mass occurs predominantly as plasma, the dissolved and suspended constituents in soil water. We applied mass balance methods to track how redistribution via plasma contributed to physical and geochemical differentiation of nine slowly eroding (~ 5 mm ky− 1) granitic catenas. The catenas were arrayed in a 3 × 3 climate by relief matrix and located in Kruger National Park, South Africa. Most of the catenas contained at least one illuviated soil profile that had undergone more volumetric expansion and less mass loss, and these soils were located in the lower halves of the slopes. By comparison, the majority of slope positions were eluviated. Soils from the wetter climates (550 and 730 mm precipitation yr− 1) generally had undergone greater collapse and lost more mass, while soils in the drier climate (470 mm yr− 1) had undergone expansion and lost less mass. Effects of differences in catena relief were less clear. Within each climate zone, soil horizon mass loss and strain were correlated, as were losses of most major elements, illustrating the predominant influence of primary mineral weathering. Nevertheless, mass loss and volumetric collapse did not become extreme because of the skeleton of resistant primary mineral grains inherited from the granite. Colloidal clay redistribution, as traced by the ratio of Ti to Zr in soil, suggested clay losses via suspension from catena eluvial zones. Thus illuviation of colloidal clays into downslope soils may be crucial to catena development by restricting subsurface flow there. Our analysis provides quantitative support for the conceptual understanding of catenas in cratonic landscapes and provides an endmember reference point in understanding the development of slowly eroding soil landscapes.

  8. Landslides as weathering reactors; links between physical erosion and weathering in rapidly eroding mountain belts

    NASA Astrophysics Data System (ADS)

    Emberson, R.; Hovius, N.; Galy, A.

    2014-12-01

    The link between physical erosion and chemical weathering is generally modelled with a surface-blanketing weathering zone, where the supply of fresh minerals is tied to the average rate of denudation. In very fast eroding environments, however, sediment production is dominated by landsliding, which acts in a stochastic fashion across the landscape, contrasting strongly with more uniform denudation models. If physical erosion is a driver of weathering at the highest erosion rates, then an alternative weathering model is required. Here we show that landslides can be effective 'weathering reactors'. Previous work modelling the effect of landslides on chemical weathering (Gabet 2007) considered the fresh bedrock surfaces exposed in landslide scars. However, fracturing during the landslide motion generates fresh surfaces, the total surface area of which exceeds that of the exposed scar by many orders of magnitude. Moreover, landslides introduce concavity into hillslopes, which acts to catch precipitation. This is funnelled into a deposit of highly fragmented rock mass with large reactive surface area and limited hydraulic conductivity (Lo et al. 2007). This allows percolating water reaction time for chemical weathering; any admixture of macerated organic debris could yield organic acid to further accelerate weathering. In the South island of New Zealand, seepage from recent landslide deposits has systematically high solute concentrations, far outstripping concentration in runoff from locations where soils are present. River total dissolved load in the western Southern Alps is highly correlated with the rate of recent (<35yrs) landsliding, suggesting that landslides are the dominant locus of weathering in this rapidly eroding landscape. A tight link between landsliding and weathering implies that localized weathering migrates through the landscape with physical erosion; this contrasts with persistent and ubiquitous weathering associated with soil production. Solute

  9. Influence of biochar and terra preta substrates on wettability and erodibility of soils

    NASA Astrophysics Data System (ADS)

    Smetanova, A.; Dotterweich, M.; Diehl, D.; Ulrich, U.; Fohrer, N.

    2012-04-01

    Biochar (BC) and terra preta substrates (TPS) have recently been promoted as soil amendments suitable for soil stabilization, soil amelioration and long-term carbon sequestration. BC is a carbon-enriched substance produced by thermal decomposition of organic material. TPS is composed of liquid and solid organic matter, including BC, altered by acid-lactic fermentation. Their effect on wettability, soil erodibility and nutrient discharge through overland flow was studied by laboratory experiments. At water contents between 0 and 100% BC is water repellent, while TPS changes from a wettable into a repellent state. The 5 and 10 vol % mixtures of BC and 10 and 20 vol% mixtures of TPS with sand remain mainly wettable during drying but repellency maxima are shifted to higher water contents with respect to pure sand and are mainly of subcritical nature. The runoff response was dominated by infiltration properties of the substrates rather than their wettability.Only one mixtures (20% TPS) produced more runoff than sandy-loamy soil on a 15% slope at an intensity of 25 mm•h-1. The 10% BC decreased runoff by up to 40%. At higher rainfall intensities (45 and 55 mm•h-1) the 10% TPS7 was up to 35% less erodible than 10% BC. Despite the TPS containing more nutrients, nutrient discharge varied between types of nutrients, slopes, rainfall intensities and mixtures. The application of a 1 cm layer onto the soil surface instead of 10% mixtures is not recommended due to high nutrient concentrations in the runoff and the wettability of pure substrates. The usage of 10% BC in lowland areas with low frequency and low-intensity precipitation and 10% TPS7 in areas with higher rainfall intensities appears to be appropriate and commendable according to current results. However, together with reversibility of repellency, it needs to undergo further examination in the field under different environmental and land use conditions Key words: biochar, terra preta substrate, wettability

  10. Wind erodibility response of physical and biological crusts to rain and flooding

    NASA Astrophysics Data System (ADS)

    Aubault, H.; Bullard, J. E.; Strong, C. L.; Ghadiri, H.; McTainsh, G. H.

    2015-12-01

    Soil surface crusts are important controllers of the small-scale wind entrainment processes that occur across all dust source regions globally. The crust type influences water and wind erosion by impacting infiltration, runoff, threshold wind velocity and surface storage capacity of both water and loose erodible material. The spatial and temporal patterning of both physical and biological crusts is known to change with rainfall and flooding. However, little is known about the impact of differing water quantity (from light rainfall through to flooding) on soil crusting characteristics (strength, roughness, sediment loss). This study compares the response of two soil types (loamy sand - LS, sandy loam - SL) with and without BSCs to three different rainfall events (2mm, 8mm, 15mm). Two BSC treatments were used one that simulated a young cyanobacteria dominated crust and an older flood induced multi species biological crust. For both soil types, soil surface strength increased with increasing rainfall amount with LS having consistently higher resistance to rupture than SL. Regardless of texture, soils with BSCs were more resistant and strength did not change in response to rainfall impact. Soil loss due to wind erosion was substantially higher on bare LS (4 times higher) and SL (3 times higher) soils compared with those with BSCs. Our results also show that young biological crust (formed by the rainfall event) have reduced soil erodibility with notably greater strength, roughness and reduced sediment losses when compared to soils with physical crust. Interestingly though, the erodibility of the old BSC did not differ greatly from that of the young BSC with respect to strength, roughness and sediment loss. This raises questions regarding the rapid soil surface protection offered by young colonising cyanobacteria crusts. Further analyses exploring the role of biological soil crusts on surface response to rainfall and wind saltation impact are ongoing.

  11. Microstructure and far infrared emission properties of tourmaline powders eroded by hydrochloric acid.

    PubMed

    Liang, Jinsheng; Li, Juan; Meng, Junping; Ding, Yan; Xue, Gang

    2010-03-01

    The microstructure and far infrared emission properties of tourmaline powders eroded by hydrochloric acid were investigated. The indexes including crystal structure, unit cell volume, microstructure and infrared spectra were characterized by X-ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The results show that the crystal structure was not changed; however, the unit cell volume decreased, the angularities of tourmaline particles became smooth, and there appeared nanohollows on their surfaces. The infrared emission properties were enhanced at proper concentrations of hydrochloric acid solutions. PMID:20355630

  12. Terrestrial photography as method to identify sediment sources in eroding rills

    NASA Astrophysics Data System (ADS)

    Wirtz, Stefan; Remke, Alexander; Wengel, René; Seeger, Manuel; Ries, Johannes B.

    2013-04-01

    One weak point in available studies on erosion processes in eroding rills is the lack of information about the real source of transported sediment. So far, such sources can only be identified by observation during the event or the experiment. Quantification is not possible by this way, additionally only large and clear visible changes are considered. In this study we present a method to quantify even small topographical changes in eroding rills during experiments or real rainfall events. We tested the suitability of DEMs created from terrestrial stereo photographies before and after application of artificial runoff to quantify eroded, transported and sedimented material in the rill. In 1 m intervals, pairs of photos are taken along the tested rills. The setup ensures that both cameras are moved with a constant parallax. The height of only about 1 m above ground level ensures that even low quantities of moved material can be identified. Based on technical data of the camera and the shot level, the theoretical accuracy of the images is below 1 mm horizontal ground resolution. The camera carrier bases on a rotating tower crane which has been developed from a customary survey tripod. The stereo images are combined with free-hand photographies from different angles of view to reach overhangs in rill sidewalls and ensure a fully 3D representation of the rill. In the analyses of the photographies 2 different kinds of software are used: The standard software Leica Photogrammetry Suite requires stereo images and ground control points whereas the open source software package is able to handle either stereo images as well as free-hand photographies. Ground control points are not needed, the software identifies point clusters which are to find in overlapping images. Using these feature-points, spatial marks are positioned which are used to match and rectify the single images to get an apposite panorama. By this way images from very different angles of view can be combined. The

  13. Numerical simulation of evolutionary erodible bedforms using the particle finite element method

    NASA Astrophysics Data System (ADS)

    Bravo, Rafael; Becker, Pablo; Ortiz, Pablo

    2016-07-01

    This paper presents a numerical strategy for the simulation of flows with evolutionary erodible boundaries. The fluid equations are fully resolved in 3D, while the sediment transport is modelled using the Exner equation and solved with an explicit Lagrangian procedure based on a fixed 2D mesh. Flow and sediment are coupled in geometry by deforming the fluid mesh in the vertical direction and in velocities with the experimental sediment flux computed using the Meyer Peter Müller model. A comparison with real experiments on channels is performed, giving good agreement.

  14. Antimicrobial peptide, hdMolluscidin, purified from the gill of the abalone, Haliotis discus.

    PubMed

    Seo, Jung-Kil; Go, Hye-Jin; Kim, Chan-Hee; Nam, Bo-Hye; Park, Nam Gyu

    2016-05-01

    A 4.7 kDa antimicrobial peptide was purified from the acidified gill extract of the Abalone, Haliotis discus, by cation-exchange and C18 reversed-phase high performance liquid chromatography (HPLC). Comparison of the amino acid sequences and molecular weight of this peptide with those of other known antimicrobial peptides revealed that this antimicrobial peptide have high sequence homology with that of cgMolluscidin and was designated hdMolluscidin. hdMolluscidin is composed of 46 amino acid residues containing several dibasic residue repeats like KK or K-R. hdMolluscidin showed potent antimicrobial activity against both Gram-positive bacteria including Bacillus subtilis and Staphylococcus aureus (minimal effective concentrations [MECs]; 0.8-19.0 μg/mL) and Gram-negative bacteria including Aeromonas hydrophila, Escherichia coli, Pseudomonas aeruginosa, Salmonella enterica, Shigella flexneri, and Vibrio parahemolyticus ([MECs]; 1.0-4.0 μg/mL) without hemolytic activity. However, hdMolluscidin did not show any significant activity against Candida albicans. The secondary structural prediction suggested that hdMolluscidin might not form an ordered or an amphipathic structure. hdMolluscidin did not show membrane permeabilization or leakage ability. The full-length hdMolluscidin cDNA contained 566-bp, including a 5'-untranslated region (UTR) of 63-bp, a 3'-UTR of 359-bp, and an open reading frame of 144-bp encoding 47 amino acids (containing Met). cDNA study of hdMolluscidin suggests that it is expressed as a mature peptide. Our results indicate that hdMolluscidin could relate to the innate immune defenses in abalone and it may not act directly on bacterial membrane. PMID:27033467

  15. Quantification of Process in AN Actively Eroding Gully-Mass Movement Complex, Waipaoa Catchment, New Zealand

    NASA Astrophysics Data System (ADS)

    Fuller, I. C.; Taylor, R.; Massey, C. I.; Marden, M.

    2012-12-01

    Tarndale Gully is a major fluvio-mass movement gully complex in the headwaters of the Waipaoa catchment, contributing c.3% of the Waipaoa sediment yield (Marden et al., 2008). Using a combination of airborne LiDAR (2005) and Terrestrial Laser Scanning (2007, 2008, 2010, 2011), this paper quantifies sediment delivery processes and slope-channel connectivity in this major contributor to the Waipaoa sediment cascade over a seven year period. Building on previous work, which inferred connectivity characteristics using RTK-dGPS surveys of the fan fed by the gully-mass movement complex (Fuller & Marden, 2011), acquisition of terrain data from high-resolution surveys of the whole gully-fan system provides new insights into slope process and slope-channel linkages operating in the complex. Raw terrain data from the airborne and ground-based laser scans were converted into raster DEMs in Arc-GIS using inverse distance weighting interpolation to a vertical accuracy between surveys of < ±0.1m. Using GIS maths functions, grid elevations in each successive DEM were subtracted from the previous DEM to provide models of change across the gully and fan complex. Deposition equates to positive vertical change, while erosion to negative vertical change in these models. Total annualised erosion equates to an average of 125,000m3 generated from the gully-mass movement complex, which is a product of debris flow, slumping and surface erosion by runoff (gullying in the conventional sense). Erosion rates from the gully complex appear to have been consistent year to year between 2005 and 2011. While the average annual volume of sediment exported to the stream system equates to 57,328 m3, this figure varies from 25,000 m3 to 110,000 m3 with no distinct correlation to rainfall. Fluctuations in stored sediment volumes account for this variation, where a critical mass in the upper fan initiates downstream progradation of sediment, building-up the lower fan. When an unknown threshold is reached, the erosion of the lower fan at its junction with the Te Weraroa Stream initiates headward excavation of this accumulated fan sediment. Rainfall data collected throughout the catchment for the period of this study, when compared with a 90 year long-term record from the catchment, suggest that 2005-2011 is not particularly exceptional in terms of storms or annual rainfall. Accordingly, since there have been no large rainfall events recorded during the period of this study, the erosion values and sediment transfer processes reported here can be considered to represent background conditions in the development and operation of this geomorphic system. References Fuller, I.C. & Marden, M. 2011. Slope-channel coupling in steepland terrain: a field-based conceptual model from the Tarndale gully and fan, Waipaoa catchment, New Zealand, Geomorphology, 128, 105-115. Marden, M. et al. 2008. Gully erosion and sediment load: Waipaoa, Waiapu and Uawa Rivers, eastern North Island, New Zealand. In: Schmidt, J. et al. (Eds), Sediment Dynamics in Changing Environments, IAHS Pub. 325, Wallingford, UK, pp. 339-350.

  16. A surface-eroding poly(1,3-trimethylene carbonate) coating for fully biodegradable magnesium-based stent applications: toward better biofunction, biodegradation and biocompatibility.

    PubMed

    Wang, Juan; He, Yonghui; Maitz, Manfred F; Collins, Boyce; Xiong, Kaiqin; Guo, Lisha; Yun, Yeoheung; Wan, Guojiang; Huang, Nan

    2013-11-01

    Biodegradable magnesium-based materials have a high potential for cardiovascular stent applications; however, there exist concerns on corrosion control and biocompatibility. A surface-eroding coating of poly(1,3-trimethylene carbonate) (PTMC) on magnesium (Mg) alloy was studied, and its dynamic degradation behavior, electrochemical corrosion, hemocompatibility and histocompatibility were investigated. The PTMC coating effectively protected the corrosion of the Mg alloy in the dynamic degradation test. The corrosion current density of the PTMC-coated alloy reduced by three orders and one order of magnitude compared to bare and poly(ε-caprolactone) (PCL)-coated Mg alloy, respectively. Static and dynamic blood tests in vitro indicated that significantly fewer platelets were adherent and activated, and fewer erythrocytes attached on the PTMC-coated surface and showed less hemolysis than on the controls. The PTMC coating after 16 weeks' subcutaneous implantation in rats maintained ~55% of its original thickness and presented a homogeneously flat surface demonstrating surface erosion, in contrast to the PCL coated control, which exhibited non-uniform bulk erosion. The Mg alloy coated with PTMC showed less volume reduction and fewer corrosion products as compared to the controls after 52 weeks in vivo. Excessive inflammation, necrosis and hydrogen gas accumulation were not observed. The homogeneous surface erosion of the PTMC coating from exterior to interior (surface-eroding behavior) and its charge neutral degradation products contribute to its excellent protective performance. It is concluded that PTMC is a promising candidate for a surface-eroding coating applied to Mg-based implants. PMID:23467041

  17. Effects of in ovo 2,3,7,8-TCDD exposure on hepatic ethoxyresorufin O-deethylase (EROD) induction and growth-related parameters in avian species

    SciTech Connect

    Janz, D.M.; Bellward, G.D.

    1994-12-31

    The effects of early in ovo TCDD exposure on CYP1A1 induction and indices of growth were determined in domestic chicken (Gallus gallus) and pigeon (Columba livia) hatchlings. TCDD (in corn oil) was injected into the air sac of eggs on embryonic day 4 (E4) (chickens, 0.1 {mu}g/kg egg; pigeons, 1.0 {mu}g/kg egg), and on E14 (pigeons, 3.0 {mu}g/kg egg). In chickens, hepatic EROD was induced 13, 15, 34, and 43-fold above control activities on E19, day of hatch (DO), day 2 after hatch (D2), and D4, respectively. Plasma thyroid hormone (T{sub 3} T{sub 4}) concentrations, which are known to peak during the perinatal period in chickens, were not affected by TCDD treatment when measured on E17, E19, D0, D2, and D4. In pigeons injected on E4, EROD was induced 15 and 6-fold on D0 and D7, respectively. There were significant decreases in yolk-free body weight, crown-rump, tibia, culmen, and wing lengths, and an elevated liver to body weight ratio (LSI) in TCDD-treated pigeons raised to D7 (p < 0.01). In pigeons injected on E14 (3{mu}g/kg), EROD was induced 14 and 10-fold on D0 and D7, respectively. Crown-rump and culmen lengths were decreased (p < 0.05) and LSI was increased (p < 0.01) on D0. There were significant decreases in all morphological parameters, and an increased LSI on D7 (p < 0.01) in TCDD-treated birds. These techniques will be used in further studies to investigate possible mechanisms of TCDD embryotoxicity in wild avian species, such as the great blue heron (Ardea herodias).

  18. Mechanisms of Toxicity of Ag Nanoparticles in Comparison to Bulk and Ionic Ag on Mussel Hemocytes and Gill Cells

    PubMed Central

    Katsumiti, Alberto; Gilliland, Douglas; Arostegui, Inmaculada; Cajaraville, Miren P.

    2015-01-01

    Silver nanoparticles (Ag NPs) are increasingly used in many products and are expected to end up in the aquatic environment. Mussels have been proposed as marine model species to evaluate NP toxicity in vitro. The objective of this work was to assess the mechanisms of toxicity of Ag NPs on mussel hemocytes and gill cells, in comparison to ionic and bulk Ag. Firstly, cytotoxicity of commercial and maltose stabilized Ag NPs was screened in parallel with the ionic and bulk forms at a wide range of concentrations in isolated mussel cells using cell viability assays. Toxicity of maltose alone was also tested. LC50 values were calculated and the most toxic Ag NPs tested were selected for a second step where sublethal concentrations of each Ag form were tested using a wide array of mechanistic tests in both cell types. Maltose-stabilized Ag NPs showed size-dependent cytotoxicity, smaller (20 nm) NPs being more toxic than larger (40 and 100 nm) NPs. Maltose alone provoked minor effects on cell viability. Ionic Ag was the most cytotoxic Ag form tested whereas bulk Ag showed similar cytotoxicity to the commercial Ag NPs. Main mechanisms of action of Ag NPs involved oxidative stress and genotoxicity in the two cell types, activation of lysosomal AcP activity, disruption of actin cytoskeleton and stimulation of phagocytosis in hemocytes and increase of MXR transport activity and inhibition of Na-K-ATPase in gill cells. Similar effects were observed after exposure to ionic and bulk Ag in the two cell types, although generally effects were more marked for the ionic form. In conclusion, results suggest that most observed responses were due at least in part to dissolved Ag. PMID:26061169

  19. Reexamination of the gill withdrawal reflex of Aplysia californica Cooper (Gastropoda; Opisthobranchia).

    PubMed

    Leonard, J L; Edstrom, J; Lukowiak, K

    1989-06-01

    The gill withdrawal reflex (GWR), an important model system for neural mechanisms of learning, varies in form and amplitude within as well as between preparations and is therefore a heterogeneous collection of action patterns, not a reflex. At least 4 action patterns occur in response to mechanical stimulation of the siphon. It is often impossible to categorize a particular movement unambiguously. All may occur spontaneously. Gill movements may be described as combinations of 10 actions; 4 involving vein movements are described here. All actions and action patterns can occur in preparations lacking the central nervous system. Some vein movements may generate considerable force without markedly altering gill area. It is suggested that this explains why some early studies failed to identify the important role of the peripheral nervous system in the GWR. Studies based on the assumption that the GWR involves a single type of movement controlled by cells of the parietovisceral ganglion require reevaluation. PMID:2544202

  20. Effect of cadmium on protein synthesis in gill tissue of marine mollusc Mytilus edulis

    SciTech Connect

    Veldhuizen-Tsoerkan, M.B.; van der Mast, C.A.; Zandee, D.I. )

    1988-09-01

    Mussels have a high capacity to accumulate cadmium and other heavy metals without notable toxic effects. However, they have recently found that cadmium is toxic to M. edulis at a relatively low concentration, as anoxic survival time of the animals was significantly shortened after two weeks of exposure to 50 ppb Cd. Based on this finding, a research was started to study the toxic effects of cadmium at a macromolecular level (proteins, RNA). Mussels were exposed to 250 ppb Cd for short periods. Then excised gills were incubated with {sup 35}s-methionine for 4 hours. In the gill tissue of 7 and 15 days Cd-exposed animals, a significantly decrease in the incorporation rate of the introduced label was found of 30 and 37%, respectively. Two-dimensional gel electrophoresis was used to analyze the de novo synthesized gill tissue proteins.

  1. Ultrastructural observations on feeding appendages and gills of Alvinella pompejana (Annelida, Polychaeta)

    NASA Astrophysics Data System (ADS)

    Storch, V.; Gaill, F.

    1986-09-01

    The feeding appendages of Alvinella pompejana obtained from a deep-sea hydrothermal vent environment are described. They are characterized by a ciliated groove, the cells of which have a very distinctive ultrastructure, by groups of bipolar receptor cells and by several kinds of gland cells. Among these, one cell type is in an upside down position suggesting a function completely different from other epidermal secretory cells. The gills differ considerably from the feeding appendages on the basis of their ultrastructure. Their epidermis is very irregular in height; basal infoldings give the blood access to a space coming very near to the external medium. The blood vascular system is open. On the other hand, the gills of Amphicteis gunneri are not effective sites of gas exchange, since their columnar epithelium is underlain with muscle cells. The cells composing the feeding appendages and gills of Alvinella pompejana are characterized by ultrastructurally very different mitochondria.

  2. Cytokine Responses in Gills of Capoeta umbla as Biomarkers of Environmental Pollution.

    PubMed

    Danabas, Durali; Yildirim, Nuran Cikcikoglu; Yildirim, Numan; Onal, Ayten Oztufekci; Uslu, Gulsad; Unlu, Erhan; Danabas, Seval; Ergin, Cemil; Tayhan, Nilgun

    2016-03-01

    Immunological biomarkers reflect the effects of exposure to environmental contaminants. In this study, the suitability and sensitivity of cytokine responses, interleukin1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α) in gill tissues of Capoeta umbla (Heckel, 1843), collected from different regions, as early warning indices of environmental pollution and ecosystem health was evaluated. Fish and water samples were taken from ten stations in March and September 2011 and 2012. Tumor necrosis factor-α, IL-1β and IL-6 levels were determined in samples of the gill tissues by using an ELISA kit. Significant variations of TNF-α, IL-1β and IL-6 levels observed between stations and seasons. The results of this study show that seasonal variations of cytokine responses in gills of Capoeta umbla are sensitive to the contaminants present in Uzuncayir Dam Lake (Tunceli, Turkey) water and are valuable biomarkers for environmental pollution and ecosystem health. PMID:26931532

  3. Histopathological effects of atrazine on gills of Caspian kutum Rutilus frisii kutum fingerlings.

    PubMed

    Khoshnood, Zahra; Jamili, Shahla; Khodabandeh, Saber

    2015-04-01

    The use of chemical pesticides has increased environmental pollution and affects fishes as non-target organisms. To investigate the toxic effects of the widely used herbicide atrazine on Caspian kutum Rutilus frisii kutum fingerlings, fish were exposed to a sublethal concentration of half LC50 for 96 h. The main alterations visible in the gill tissue were detachment of the epithelium of the lamellae, necrosis, lamellar fusion, hyperplasia, club shaped lamellae, collapse of the lamellae, shrinkage and curling of the lamellae, and ultrastructural alterations such as necrosis of the apical microridges of the pavement cells. Results also showed that the gill ionocytes were fewer in number and larger in size in the atrazine-exposed fish. Atrazine appears to be highly toxic to Caspian kutum fingerlings even at a sublethal concentration (12.47 mg l(-1)) and acute exposure. This toxicity could affect gill respiration and ion regulation function of fingerlings by damaging tissue, pavement cells, and ionocytes. PMID:25850400

  4. Gill ectoparasites of Barbus martorelli (Teleostean: Cyprinidae) from a tropical watercourse (Cameroon, Africa): conflict or coexistence?

    PubMed Central

    Tombi, J.; Bilong Bilong, C.F.; Morand, S.

    2011-01-01

    The structure and stability of parasite communities have been mainly explained by high diversity and strong interactions among parasite species. During 16 months, 558 Barbus martorelli gill infracommunities were studied in a tropical zone to determine whether parasite infrapopulations interact. Three levels were retained: the infracommunity level, the gill filament level, and the filament fraction level. Single species infections in Barbus martorelli were very rare and only concerned the core species: Dactylogyrus bopeleti, D. insolitus, D. simplex and Myxobolus barbi. Mixed infections appeared as a general rule in this fish species. Interspecific interactions at all three levels were statistically non significant. Our results suggest that Barbus martorelli gill parasites are non interactive (isolationist). PMID:21395208

  5. Erodibility of Titan ice bedrock constrained by laboratory measurements of ice strength and erosion by sediment impacts

    NASA Astrophysics Data System (ADS)

    Sklar, L. S.; Collins, G. C.; Litwin, K. L.; Polito, P. J.; Zygielbaum, B. R.

    2012-12-01

    Saturn's moon Titan has a remarkably earth-like surface morphology, with branching fluvial networks draining elevated terrain. A paucity of impact craters suggests fluvial dissection is active and that the pace of landscape evolution is rapid. A key limitation on modeling rates of incision by Titan's rivers of liquid methane has been a lack of information on the erodibility of water-ice bedrock at ultra-cold temperatures. Here we report results from laboratory measurements of ice resistance to tensile fracture and rates of erosion of Titan bedrock analogs by low-velocity sediment impacts. We apply these experimental results to modeling fluvial incision, and explore constraints on rates and frequency of channel cutting on Titan. We made test samples of polycrystalline ice with a narrow and wide size distribution of seed ice grains. For some samples we added solid impurities composed of basalt, urea, and ammonium-sulfate, to account for the possibility that Titan's ice bedrock also contains silicates from meteors, organic polymers derived from Titan's atmosphere, and ammonia-based compounds formed by cryovolcanism. The experiments were conducted in a walk-in freezer and environmental chamber, where we varied temperature between 260 and 110 K using dry ice and liquid nitrogen (LN). For terrestrial rocks, resistance to erosion by sediment impacts depends on the kinetic energy required to detach a unit volume, which has been shown to scale with the square of tensile strength. We measured the tensile strength of Titan bedrock analogs using the Brazilian splitting test and found that strength increases with decreasing temperature at 7 kPa/K, for all ice types tested. Ice at Titan temperatures is thus roughly twice as strong as at terrestrial conditions; ice is strengthened by increasing impurity concentrations, finer grain-size distributions, and lower porosity. To replicate erosion of ice bedrock by bedload sediment impacts, we filled a 55-gallon drum with various ice

  6. Endosulfan acute toxicity in Bufo bufo gills: ultrastructural changes and nitric oxide synthase localization.

    PubMed

    Bernabò, Ilaria; Brunelli, Elvira; Berg, Cecilia; Bonacci, Antonella; Tripepi, Sandro

    2008-02-18

    Endosulfan is an organochlorine pesticide used in agriculture for a wide range of crops. Endosulfan concentrations of up to 0.7 mg/L can be found in ponds and streams near sprayed agricultural fields. We investigated the short-term toxicity of endosulfan in common toad (Bufo bufo) tadpoles after 24, 48, and 96 h of exposure. Acute toxicity was evaluated at nominal concentrations ranging from 0.01 to 0.6 mg/L: concentrations that could be found after the application of pesticide. Our results show that 0.43 mg/L of endosulfan caused 50% mortality (LC(50)). The effects of a sublethal endosulfan concentration (0.2mg/L) on gill apparatus morphology were evaluated by scanning and transmission electron microscopy. Immunohistochemical methods were also applied to detect the expression pattern of the inducible isoform of nitric oxide synthase (iNOS) in the gills using the confocal laser scanner microscope. Exposure to 0.2mg/L of endosulfan caused an apparent increase in mucus production, the occurrence of secretory vesicles and lamellar bodies, a widening of intercellular spaces and additionally there was evidence of an inflammatory response in the gill apparatus. The morphological alterations occurred after 24h and were more pronounced after 48 and 96 h of exposure. Altered morphology and increased mucus secretion indicate impaired gas exchange and osmoregulation in the gills. In addition, there was an increase of iNOS expression after 24 and 48 h which may reflect hypoxia and inflammation in the gill epithelium. Our results clearly indicate that short-term exposure to a sublethal concentration of endosulfan, near the high end of the environmental range, disrupts gill morphology and function in B. bufo tadpoles. PMID:18243363

  7. Deficiency of dietary niacin impaired gill immunity and antioxidant capacity, and changes its tight junction proteins via regulating NF-κB, TOR, Nrf2 and MLCK signaling pathways in young grass carp (Ctenopharyngodon idella).

    PubMed

    Li, Shun-Quan; Feng, Lin; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

    2016-08-01

    To investigate the effects of dietary niacin on gill immunity, tight junction proteins, antioxidant system and related signaling molecules mRNA expression, young grass carp (Ctenopharyngodon idella) were fed six diets containing graded levels of niacin (3.95-55.01 mg/kg diet) for 8 weeks. The study indicated that niacin deficiency decreased lysozyme and acid phosphatase activities, and complement 3 content, and caused oxidative damage that might be partly due to the decreased copper, zinc superoxide dismutase, catalase, glutathione reductase, glutathione peroxidase and glutathione-S-transferase activities and reduced glutathione content in fish gills (P < 0.05). Moreover, the relative mRNA levels of antimicrobial peptides (liver expressed antimicrobial peptide 2 and Hepcidin), anti-inflammatory cytokines (interleukin 10 and transforming growth factor β1), tight junction proteins (Occludin, zonula occludens 1, Claudin-15 and -3), signaling molecules (inhibitor of κBα (IκBα), target of rapamycin (TOR), ribosomal protein S6 kinase 1 (S6K1) and NF-E2-related factor 2 (Nrf2)) and antioxidant enzymes were significantly decreased (P < 0.05) in niacin-deficient diet group. Conversely, the mRNA levels of pro-inflammatory cytokines (tumor necrosis factor α, interleukin 8, interferon γ2, and interleukin 1β), signaling molecules (nuclear factor kappa B p65, IκB kinase α, IκB kinase β, IκB kinase γ, Kelch-like-ECH-associated protein 1b, myosin light chain kinase and p38 mitogen-activated protein kinase (p38 MAPK) were significantly increased (P < 0.05) in fish gills fed niacin-deficient diet. Interestingly, the varying niacin levels of 3.95-55.01 mg/kg diet had no effect on the mRNA level of Kelch-like-ECH-associated protein 1a, Claudin-c and -12 in fish gills (P > 0.05). In conclusion, niacin deficiency decreased gill immunity, impaired gill antioxidant system, as well as regulated mRNA expression of gill tight junction proteins and related signaling

  8. Remote Sensing Analysis of a Rapidly Eroding Sea Cliff at Point Grey, British Columbia

    NASA Astrophysics Data System (ADS)

    Westin, A. M.; Francioni, M.; Kremsater, R.; Stead, D.; Clague, J. J.

    2015-12-01

    A range of remote sensing tools can be used to document hazardous and sensitive environments. Presented at this time are the first results of an ongoing study of a rapidly eroding, steep sea cliff in Vancouver, British Columbia. The sea cliff is formed in a 70-m-thick sequence of outwash sands and silts (Quadra Sand) deposited during the early part of the last glaciation, known locally as the Fraser Glaciation. The sea cliff is unstable and retreating due to wave attack, groundwater seepage, and shallow-seated landslides. If no measures are taken to stem wave erosion, the sea cliff will likely retreat faster with rising seas over the remainder of this century. The beach below the cliff is a popular recreational location, thus a hard engineering solution to the erosion problem might be unacceptable to Vancouver residents. We have used conventional photogrammetry, structures from motion, thermal imaging, and terrestrial full waveform laser scanning to provide base-line spatial data for the most rapidly eroding section of the cliff. Here, we present some of our results and discuss the challenges that we faced in characterizing this large soil slope.

  9. Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershed

    NASA Astrophysics Data System (ADS)

    Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.

    2015-04-01

    The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

  10. Persistence of soil organic matter in eroding versus depositional landform positions

    USGS Publications Warehouse

    Berhe, Asmeret Asefaw; Harden, Jennifer W.; Torn, Margaret S.; Kleber, Markus; Burton, Sarah D.; Harte, John

    2012-01-01

    Soil organic matter (SOM) processes in dynamic landscapes are strongly influenced by soil erosion and sedimentation. We determined the contribution of physical isolation of organic matter (OM) inside aggregates, chemical interaction of OM with soil minerals, and molecular structure of SOM in controlling storage and persistence of SOM in different types of eroding and depositional landform positions. By combining density fractionation with elemental and spectroscopic analyses, we showed that SOM in depositional settings is less transformed and better preserved than SOM in eroding landform positions. However, which environmental factors exert primary control on storage and persistence of SOM depended on the nature of the landform position considered. In an annual grassland watershed, protection of SOM by physical isolation inside aggregates and chemical association of organic matter (complexation) with soil minerals, as assessed by correlation with radiocarbon concentration, were more effective in the poorly drained, lowest-lying depositional landform positions, compared to well-drained landform positions in the upper parts of the watershed. Results of this study demonstrated that processes of soil erosion and deposition are important mechanisms of long-term OM stabilization.

  11. Solute transport in eroded and rehabilitated prairie landforms. 1. Nonreactive solute.

    PubMed

    Papiernik, Sharon K; Koskinen, William C; Yates, Scott R

    2009-08-26

    Information regarding solute and water transport as affected by soil properties, topography, and climatic conditions is required to improve and validate transport models. This study evaluated the dissipation of bromide applied to the soil surface in the fall and spring to undisturbed (eroded) and rehabilitated landforms, in which topsoil was moved from depositional areas to the eroded upper slope. Despite large changes in soil properties, the amount and center of mass of bromide remaining in the top 1 m of soil was the same in undisturbed and rehabilitated plots. Approximately 60% of the fall-applied bromide was lost during the winter and early spring, presumably due to leaching and runoff. The center of mass of spring-applied bromide remained at depths of <30 cm. At the end of the experiment, 33% of the spring-applied bromide was detected in soil and 56% in corn plants. These results suggest that little bromide was leached out of the root zone in the spring and that plant uptake was a major route of bromide dissipation during the growing season. PMID:19653694

  12. Solute transport in eroded and rehabilitated prairie landforms. 2. Reactive solute.

    PubMed

    Papiernik, Sharon K; Koskinen, William C; Yates, Scott R

    2009-08-26

    The impact of varying soil, landscape, and climate conditions on the off-site transport of pesticides must be determined to develop improved pesticide management practices. This study quantified the rate of S-metolachlor dissipation after fall and spring application in eroded and rehabilitated landforms in which topsoil was moved from the lower slope to the upper slope. Fall-applied metolachlor provided no control of annual grasses because approximately 80% was removed from the root zone during the winter and early spring, presumably by leaching and runoff. S-Metolachlor dissipated in the spring with a DT(50) of 24-29 days. These results suggest that fall-applied metolachlor may not provide economic weed control and presents an increased risk of water contamination. Although landscape position and bulk soil movement within the landform had a large impact on soil properties, no significant differences in metolachlor dissipation between different landscape positions and between eroded and rehabilitated landforms were observed. PMID:19653695

  13. SUMO-Dependent Relocalization of Eroded Telomeres to Nuclear Pore Complexes Controls Telomere Recombination.

    PubMed

    Churikov, Dmitri; Charifi, Ferose; Eckert-Boulet, Nadine; Silva, Sonia; Simon, Marie-Noelle; Lisby, Michael; Géli, Vincent

    2016-05-10

    In budding yeast, inactivation of telomerase and ensuing telomere erosion cause relocalization of telomeres to nuclear pore complexes (NPCs). However, neither the mechanism of such relocalization nor its significance are understood. We report that proteins bound to eroded telomeres are recognized by the SUMO (small ubiquitin-like modifier)-targeted ubiquitin ligase (STUbL) Slx5-Slx8 and become increasingly SUMOylated. Recruitment of Slx5-Slx8 to eroded telomeres facilitates telomere relocalization to NPCs and type II telomere recombination, a counterpart of mammalian alternative lengthening of telomeres (ALT). Moreover, artificial tethering of a telomere to a NPC promotes type II telomere recombination but cannot bypass the lack of Slx5-Slx8 in this process. Together, our results indicate that SUMOylation positively contributes to telomere relocalization to the NPC, where poly-SUMOylated proteins that accumulated over time have to be removed. We propose that STUbL-dependent relocalization of telomeres to NPCs constitutes a pathway in which excessively SUMOylated proteins are removed from "congested" intermediates to ensure unconventional recombination. PMID:27134164

  14. Spatial variability of soil properties and soil erodibility in the Alqueva dam watershed, Portugal

    NASA Astrophysics Data System (ADS)

    Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.

    2015-01-01

    The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this, three areas representative of different land uses (agroforestry grassland, Lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while K factor increased with intensive cultivation. The HJ-biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

  15. Dr Anthony Dobell, Legendary McGill Trailblazer: May 7, 1927, to June 17, 2015.

    PubMed

    Mulder, David S

    2015-12-01

    Anthony R. C. Dobell died on June 17, 2015, at the age of 88. Dobell was the first Canadian president of the Society of Thoracic Surgeons. He was a pioneer in the development of pediatric and adult cardiac surgery at McGill University. He was inspired by Dr John Gibbon during his residency training at Jefferson Medical College in Philadelphia. He developed a McGill-based residency in Cardiothoracic Surgery and always took pride in the legacy of more than 40 residents scattered throughout North America. PMID:26652547

  16. Hyperparasitism of trichodinid ciliates on monogenean gill flukes of two marine fish.

    PubMed

    Colorni, A; Diamant, A

    2005-06-01

    Two unusual cases of hyperparasitism of trichodinid ciliates on monogenean gill flukes are described from southern Israel (Red Sea). The first case occurred in cultured European sea bass Dicentrarchus labrax infected by Diplectanum aequans, while the second was observed in a feral devil firefish Pterois miles infected by Haliotrema sp. In both cases, the trichodinids heavily co-infested the host fish gills. The flukes were completely coated by the ciliates, which gave them a cobblestone appearance, but no damage to their tegument was apparent. Both cases are most likely a result of accidental hyperparasitism, brought about by perturbed environmental conditions. PMID:16060271

  17. Isolation and partial characterization of a novel virus from different carp species suffering gill necrosis - ultrastructure and morphogenesis.

    PubMed

    Granzow, H; Fichtner, D; Schütze, H; Lenk, M; Dresenkamp, B; Nieper, H; Mettenleiter, T C

    2014-06-01

    Two isolates of a novel enveloped RNA virus were obtained from carp and koi carp with gill necrosis. Both isolates behaved identically and could be propagated in different cyprinid cell lines forming large syncytia. The virus was sensitive to lipid solvents and neither exhibited haemadsorption/haemagglutination nor reverse transcriptase activity. Mature virus particles displayed a spherical shape with diameter of 100-350 nm after negative staining and 100-300 nm in ultrathin sections, covered by short projections of 8-10 nm in length. Maturation of virus progeny was shown to occur by budding and envelopment of the filamentous helical nucleocapsids at the cell surface. A detailed comparison of ultrastructure and morphogenesis of the novel virus isolates with selected arena-, ortho- and paramyxoviruses as possible candidates for evaluation of taxonomic classification yielded no consistency in all phenotypic features. Thus, on the basis of ultrastructure the novel virus isolates could not be assigned unequivocally to any established virus family. PMID:23865968

  18. Reconstruction of eroded and deposited sediment volumes in the floodplains of the embanked River Waal, the Netherlands, for the period 1650 - 1850 AD

    NASA Astrophysics Data System (ADS)

    Hobo, Noortje; Makaske, Bart; Middelkoop, Hans

    2010-05-01

    The embanked floodplains of the River Waal developed as a result of stepwise downstream migration of meander bends between confining dykes. Accretion in the upstream limb of the outer bend - enhanced by groynes and trees - and erosion in the downstream limb have resulted in a series of successively developed sand bars, separated by secondary channels. On top of the sand bars and the secondary channel fills, fine-grained overbank sediments were deposited. Downstream migration ceased around 1850 AD, when the river bed was fixed by large-scale construction of groynes, and only overbank deposition continued. Eroded and deposited sediment volumes associated with downstream migration are affected by human activities. Goal of the present research is to estimate a sediment budget for a 12-km-long section along the River Waal, by quantifying the amount of erosion and deposition. We estimated these volumes for time slices of 50 years, between 1650 and 1850 AD, in order to be able to assess the variable impact of human interference during this period. To estimate erosion, we created geomorphological maps for all time slices, based on maps dating from the 17th century to present. In these maps, distinction is made between sand bars, residual channels, and older deposits (all sediments deposited before 1650 AD). Comparison between all maps allowed us to calculate the eroded area per time slice. Eroded volumes were hence estimated by multiplying the eroded area by the average river depth at that period, which is assumed to be the erosion depth. For estimation of deposition we used lithological cross-sections. These cross-sections are positioned such that every sand bar and every residual channel is represented in at least one cross-section. In every cross-section isochrones were drawn, based on OSL datings, chronologic interpretation of heavy metal profiles, and the historical maps. These isochrones are used to calculate the thickness of the sand bars, the residual channel fills

  19. Granular flows on erodible layers: type and evolution of flow and deposit structures

    NASA Astrophysics Data System (ADS)

    Crosta, G.; De Blasio, F.; De Caro, M.; Volpi, G.; Frattini, P.

    2012-04-01

    The interaction of a fast moving landslide mass with the basal layer over which movement takes place has been discussed in previous contributions. Nevertheless, the evolution of the structures within the moving mass and the erodible layer are still to be described in detail (Hungr and Evans, 2004; Crosta et al., 1992, 2006, 2009, 2011; Dufresne et al., 2010; Mangeney et al., 2010) and modeling results (Crosta et al., 2006, 2009, 2011; Mangeney et al., 2010). We present some of the results from a campaign of laboratory experiments aimed at studying the evolution of a granular flow at the impact with and during the successive spreading over a cohesionless erodible layer. We performed these test to study the processes and to collect data and evidences to compare them with the results of numerical simulations and to verify capabilities of numerical codes. The laboratory setup consists of an inclined slope and an horizontal sector where release and transport, and deposition take place, respectively. Materials used for the tests are: a uniform rounded siliceous sand (Hostun sand; 0.125-0.5 mm) commonly adopted in lab tests because free of scale effects, and a gravel made of angular elements (12 mm in ave. size). Both the materials have been tested in dry conditions. Different slope angles have been tested (40, 45, 50, 55, 50, 66°) as well as different thicknesses of the erodible layer (0, 0.5, 1, 2 cm) and volumes of the released material (1.5, 3, 5, 9.6 liters). Tests have been monitored by means of a high speed camera and the pre- and post-failure geometries have been surveyed by means of a laser scanner. Deposit description allowed also the computation of volumes and the characterization of the different structures developed and frozen into the deposit. Experiments allowed us to observe the extreme processes occurring during the movement and the mise en place of the deposits. In particular, we observe the formation of a clear wave-like feature developing during the

  20. Sediment erodability in sediment transport modelling: Can we account for biota effects?

    NASA Astrophysics Data System (ADS)

    Le Hir, P.; Monbet, Y.; Orvain, F.

    2007-05-01

    Sediment erosion results from hydrodynamic forcing, represented by the bottom shear stress (BSS), and from the erodability of the sediment, defined by the critical erosion shear stress and the erosion rate. Abundant literature has dealt with the effects of biological components on sediment erodability and concluded that sediment processes are highly sensitive to the biota. However, very few sediment transport models account for these effects. We provide some background on the computation of BSS, and on the classical erosion laws for fine sand and mud, followed by a brief review of biota effects with the aim of quantifying the latter into generic formulations, where applicable. The effects of macrophytes, microphytobenthos, and macrofauna are considered in succession. Marine vegetation enhances the bottom dissipation of current energy, but also reduces shear stress at the sediment-water interface, which can be significant when the shoot density is high. The microphytobenthos and secreted extracellular polymeric substances (EPS) stabilise the sediment, and an increase of up to a factor of 5 can be assigned to the erosion threshold on muddy beds. However, the consequences with respect to the erosion rate are debatable since, once the protective biofilm is eroded, the underlying sediment probably has the same erosion behaviour as bare sediment. In addition, the development of benthic diatoms tends to be seasonal, so that stabilising effects are likely to be minimal in winter. Macrofaunal effects are characterised by extreme variability. For muddy sediments, destabilisation seems to be the general trend; this can become critical when benthic communities settle on consolidated sediments that would not be eroded if they remained bare. Biodeposition and bioresuspension fluxes are mentioned, for comparison with hydrodynamically induced erosion rates. Unlike the microphytobenthos, epifaunal benthic organisms create local roughness and are likely to change the BSS generated

  1. Stable isotopes and chemical composition at different spatial scales indicate sink function of eroded OC in a tropical catchment

    NASA Astrophysics Data System (ADS)

    Chaplot, V.; Rumpel, C.; Fontaine, S.; Bouahom, B.; Valentin, C.

    2009-04-01

    Our objective was to evaluate the fate of eroded carbon at landscape level in a steep slope area of the Mekong basin submitted to traditional slash-and-burn (SAB) agriculture. We monitored carbon erosion at different spatial scales ranging from 1m² (micro-plot level) installed within a hillslope to 1×107 m² (watershed). Samples were taken throughout the 2003 rainy season, in order to quantitatively assess the fate of eroded OC. Laboratory analysis of the chemical composition of eroded OC by analysis for its elemental, istotopic (13C, 15N, 14C) and bulk chemical composition were performed to assess potential microbial decomposition of eroded sediment during transport and sedimentation. Our data show, that 92.7% of eroded OC were sedimented at a distance lower that 1.5m from its source. Analysis of the composition of eroded organic matter at different scales showed a significant decrease of the C/N ratio and an enrichment of 13C and 15N isotopes, which occurred within the hillslope and in first order reaches. These changes were interpreted as resulting from OC decomposition and used to assess the CO2 emissions, which might have occurred during the erosion process. Our results indicate, that within the hillslope, potential CO2 emissions with 0.43 gCm-2y-1 would be 3.3 times higher than the OC exports by water erosion but represented about 10% only of the OC deposited. Potential CO2 emissions during the transport from the hillslope to the watershed outlet would represent 14% of total eroded OC. Based on these results, we suggest that erosion induced OC sequestration amounts to 43 gCm-2y-1 in the hillslope and, 33 gCm-2y-1 at the watershed level.

  2. Effects of salinity on the accumulation of hemocyte aggregates and bacteria in the gills of Callinectes sapidus, the Atlantic blue crab, injected with Vibrio campbellii.

    PubMed

    Ikerd, Jennifer L; Burnett, Karen G; Burnett, Louis E

    2015-05-01

    In addition to respiration and ion regulation, crustacean gills accumulate and eliminate injected particles, along with hemocyte aggregates that form in response to those particles. Here we report that the dose of Vibrio campbellii previously shown to induce a decrease in respiration and hemolymph flow across the gill in the Atlantic blue crab, Callinectes sapidus, also triggered the formation of aggregates containing four or more hemocytes in the gills, compared with saline-injected controls. More bacteria were trapped and rendered non-culturable per unit weight by anterior respiratory gills than posterior gills specialized for ion regulation. Further, more bacteria accumulated in the anterior gills of animals held at 30 ppt than those at 10 ppt. Thus, the role of the gills in immune defense comes at an energetic cost to this and likely to other crustaceans; this cost is influenced by acclimation salinity and the position and specialized function of individual gills. PMID:25541183

  3. Temporal variation in the antioxidant defence system and lipid peroxidation in the gills and mantle of hydrothermal vent mussel Bathymodiolus azoricus

    NASA Astrophysics Data System (ADS)

    Company, Rui; Serafim, Angela; Cosson, Richard; Fiala-Médioni, Aline; Dixon, David; João Bebianno, Maria

    2006-07-01

    Hydrothermal vent mussels are exposed continually to toxic compounds, including high metal concentrations and other substances like dissolved sulphide, methane and natural radioactivity. Fluctuations in these parameters appear to be common because of the characteristic instability of the hydrothermal environment. Temporal variation in the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidases (Total GPx), selenium dependent glutathione peroxidases (Se-GPx)), metallothioneins and lipid peroxidation (LPO) in the gills and mantle of the mussel Bathymodiolus azoricus from Menez-Gwen hydrothermal vent site was evaluated and related to the accumulated metal concentrations (Ag, Cu, Cd, Fe, Mn and Zn) in the tissues. Maximum antioxidant enzyme activities in the gills were detected in the beginning of summer, followed by a gradual decrease throughout the following months. One year after, the levels of antioxidant enzyme activities were similar to those reported one year before. LPO in this tissue exhibited a similar temporal variation trend. A different pattern of temporal variation in antioxidant enzyme activities was observed in the mantle, with a gradual increase from summer to the end of autumn (November). LPO in the mantle exhibited an almost reverse trend of temporal variation to that of antioxidant enzyme activities in this tissue. Antioxidant defences in the gills of B. azoricus were significantly enhanced with increasing concentrations of Ag, Cu and Mn, while negative relationships between antioxidant enzymes and Cd, Cu, Mn and Zn concentrations in the mantle were observed, suggesting different pathways of reactive oxygen species (ROS) production and that these tissues responded differently to the metal accumulation. However, temporal variation in biomarkers of defence and damage were in general similar to coastal bivalve species and can be associated with temporal variations of the physiological status due to reproduction

  4. Modulation of immune response, physical barrier and related signaling factors in the gills of juvenile grass carp (Ctenopharyngodon idella) fed supplemented diet with phospholipids.

    PubMed

    Feng, Lin; Chen, Yong-Po; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Zhao, Juan; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

    2016-01-01

    This study was conducted to investigate the effects of dietary phospholipids (PL) on the gill immune response and physical barrier of juvenile grass carp (Ctenopharyngodon idella). A total of 1080 juvenile grass carp with an average initial weight of 9.34 ± 0.03 g were fed six semi-purified diets containing 0.40% (unsupplemented control group), 1.43%, 2.38%, 3.29%, 4.37% and 5.42% PL for 2 months. Compared with the control group, optimal PL supplementation increased (P < 0.05): (1) the lysozyme activity, acid phosphatase activity, complement component 3 (C3) content, liver expressed antimicrobial peptide 1 (LEAP-1) and LEAP-2 mRNA expression; (2) the relative mRNA expression of interleukin 10, transforming growth factor β1, inhibitor factor κBα (IκBα) and target of rapamycin (TOR); (3) the activities of anti-superoxide anion (ASA), anti-hydroxyl radical (AHR), copper/zinc superoxide dismutase (SOD1), catalase (CAT), glutathione peroxidase (GPx) and glutathione reductase (GR), glutathione content and mRNA levels of SOD1, CAT, GPx, GR and NF-E2-related factor 2 (Nrf2) genes; (4) the transcription abundance of occludin, claudin b, claudin c, claudin 12 and zonula occludens 1 genes. At the same time, appropriate PL supplementation decreased (P < 0.05): (1) tumor necrosis factor α, interleukin 1β, nuclear factor κB p65 (NF-κB p65), IκB kinase β (IKKβ) and IκB kinase γ (IKKγ) mRNA expression; (2) malondialdehyde (MDA), protein carbonyl (PC) and reactive oxygen species (ROS) content and the relative mRNA expression of Kelch-like-ECH-associated protein 1a (Keap1a) and Keap1b; (3) the transcription abundance of myosin light chain kinase (MLCK) and p38 mitogen-activated protein kinase (p38 MAPK) genes. In conclusion, the positive effect of PL on gill health is associated with the improvement of the immunity, antioxidant status and tight junction barrier of fish gills. Finally, based on ACP activity, C3 content, PC content and ASA activity in the gills

  5. The effect of a desensitizer and CO2 laser irradiation on bond performance between eroded dentin and resin composite

    PubMed Central

    Ding, Meng; Shin, Sang-Wan; Kim, Min-Soo

    2014-01-01

    PURPOSE This study was aimed to evaluate effect of the desensitizing pretreatments on the micro-tensile bond strengths (µTBS) to eroded dentin and sound dentin. MATERIALS AND METHODS Forty-two extracted molars were prepared to form a flat dentin surface, and then they were divided into two groups. Group I was stored in distilled water while group II was subjected to a pH cycling. Each group was then subdivided into three subgroups according to desensitizing pretreatment used: a) pretreatment with desensitizer (Gluma); b) pretreatment with CO2 Laser (Ultra Dream Pluse); c) without any pretreatment. All prepared surfaces were bonded with Single Bond 2 and built up with resin composite (Filtek Z250). The micro-tensile bond test was performed. Fracture modes were evaluated by stereomicroscopy. Pretreated surfaces and bonded interfaces were characterized by scanning electron microscope (SEM). The data obtained was analyzed by two-way ANOVA (α=0.05). RESULTS For both sound and eroded dentin, samples treated with desensitizer showed the greatest µTBS, followed by samples without any treatment. And samples treated with CO2 laser showed the lowest µTBS. SEM study indicated that teeth with eroded dentin appeared prone to debonding, as demonstrated by existence of large gaps between adhesive layers and dentin. CONCLUSION Pretreatment with Gluma increased the µTBS of Single Bond 2 for eroded and sound teeth. CO2 laser irradiation weakened bond performance for sound teeth but had no effect on eroded teeth. PMID:25006379

  6. Permeability properties and occludin expression in a primary cultured model gill epithelium from the stenohaline freshwater goldfish.

    PubMed

    Chasiotis, Helen; Kelly, Scott P

    2011-05-01

    Techniques for the primary culture of fish gill epithelia on permeable supports have provided 'reconstructed' gill models appropriate for the study of gill permeability characteristics in vitro. Models developed thus far have been derived from euryhaline fish species that can tolerate a wide range of environmental salinity. This study reports on procedures for the primary culture of a model gill epithelium derived from goldfish, a stenohaline freshwater (FW) fish that cannot tolerate high environmental salt concentrations. The reconstructed goldfish gill epithelium was cultured on permeable filter inserts and using electron microscopy and immunocytochemical techniques, was determined to be composed exclusively of gill pavement cells. When cultured under symmetrical conditions (i.e. with culture medium bathing both apical and basolateral surfaces), epithelial preparations generated appreciable transepithelial resistance (TER) (e.g. 1,150 ± 46 Ωcm(2)) within 36-42 h post-seeding in inserts. When apical medium was replaced with FW (asymmetrical conditions to mimic conditions that occur in vivo), epithelia exhibited increased TER and elevated paracellular permeability. Changes in permeability occurred in association with altered occludin-immunoreactive band position by western blot and no change in occludin mRNA abundance. We contend that the goldfish gill model will provide a useful in vitro tool for examining the molecular components of a stenohaline fish gill epithelium that participate in the regulation of gill permeability. The model will allow molecular observations to be made together with assessment of changing physiological properties that relate to permeability. Together, this will allow further insight into mechanisms that regulate gill permeability in fishes. PMID:21085969

  7. Demonstrating Theory in Practice: Examples of the McGill Model of Nursing.

    ERIC Educational Resources Information Center

    Gaudine, Alice P.

    2001-01-01

    A workshop on the McGill Model of Nursing, which depicts nurses' role in developing and maintaining family health, was attended by 147 nurses. Increases in self-efficacy, behavior, and performance related to implementing the model were evident 6 months after the workshop. (SK)

  8. Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills.

    PubMed

    Wiik-Nielsen, J; Mo, T A; Kolstad, H; Mohammad, S N; Hytterød, S; Powell, M D

    2016-09-01

    Amoebic gill disease (AGD) caused by the ectoparasite Paramoeba perurans affects several cultured marine fish species worldwide. In this study, the morphology and ultrastructure of P. perurans in vitro and in vivo was investigated using scanning and transmission electron microscopy (SEM and TEM, respectively). Amoebae cultures contained several different morphologies ranging from a distinct rounded cell structure and polymorphic cells with pseudopodia of different lengths and shapes. SEM studies of the gills of AGD-affected Atlantic salmon, Salmo salar L., revealed the presence of enlarged swellings in affected gill filaments and fusion of adjacent lamellae. Spherical amoebae appeared to embed within the epithelium, and subsequently leave hemispherical indentations with visible fenestrations in the basolateral surface following their departure. These fenestrated structures corresponded to the presence of pseudopodia which could be seen by TEM to penetrate into the epithelium. The membrane-membrane interface contained an amorphous and slightly fibrous matrix. This suggests the existence of cellular glycocalyces and a role for extracellular products in mediating pathological changes in amoebic gill disease. PMID:26775899

  9. ALPHA METHYLGLUCOSIDE TRANSPORT BY THE GILL OF THE OYSTER 'OSTREA EDULIS'

    EPA Science Inventory

    The present study defines the mechanism of glucose transport in the isolated gill of oysters, using the European flat oyster, Ostrea edulis, as a representative species. The specific objectives were: (1) identify a non-metabolized transport analog, (2) determine the effects of kn...

  10. 78 FR 53666 - Drawbridge Operation Regulation; Wolf River, Gills Landing and Winneconne, WI

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-30

    ... Operation Regulation; Wolf River, Gills Landing and Winneconne, WI'' in the Federal Register (78 FR 27336... Acronyms CFR Code of Federal Regulations DHS Department of Homeland Security FR Federal Register NPRM... SECURITY Coast Guard 33 CFR Part 117 RIN 1625-AA09 Drawbridge Operation Regulation; Wolf River,...

  11. Gill net saturation by lake trout in Michigan waters of Lake Superior

    USGS Publications Warehouse

    Hansen, Michael J.; Schorfhaar, Richard G.; Selgeby, James H.

    1998-01-01

    We conducted experimental fishing for lake trout Salvelinus namaycush in Michigan waters of Lake Superior to determine the importance of soak time on catch per effort (CPE) in numbers per kilometer of standard gill net. We modeled CPE as a nonlinear function of the number of nights between setting and lifting (soak time), in which the nets fill at a certain rate toward some maximum after which the nets cannot hold more fish. We found that lake trout CPE increased with soak time at a rate that varied with lake trout density toward a saturation level that was independent of lake trout density. The CPE values of nets soaked 2–5 nights divided by the CPE of nets soaked 1 night were significantly lower than would be expected had CPE increased as a linear function of the number of nights soaked. We derived a means for correcting gill-net CPE values for differing soak times to a common base of 1 night soaked. We concluded that it is inappropriate to assume lake trout catches in gill nets will increase in direct proportion to the number of nights soaked and recommend that CPE of lake trout in gill nets be corrected for soak time.

  12. Electronic Thesis Initiative: Pilot Project of McGill University, Montreal

    ERIC Educational Resources Information Center

    Park, Eun G.; Zou, Qing; McKnight, David

    2007-01-01

    Purpose: To set up a protocol for electronic thesis and dissertation (ETD) submission for the electronic thesis initiative pilot project at McGill University in Montreal, Canada. Design/methodology/approach: An electronic thesis and dissertation submission protocol was implemented and tested. To test authoring tools, we had 50 students submit…

  13. Characterization of cadmium plasma membrane transport in gills of a mangrove crab Ucides cordatus.

    PubMed

    Ortega, P; Custódio, M R; Zanotto, F P

    2014-12-01

    Membrane pathway for intracellular cadmium (Cd(2+)) accumulation is not fully elucidated in many organisms and has not been studied in crab gill cells. To characterize membrane Cd(2+) transport of anterior and posterior gill cells of Ucides cordatus, a hypo-hyper-regulating crab, a change in intracellular Cd(2+) concentration under various experimental conditions was examined by using FluoZin, a fluorescent probe. The membrane Cd(2+) transport was estimated by the augmentation of FluoZin fluorescence induced by extracellular application of CdCl2 and different inhibitors. Addition of extracellular calcium (Ca(2+)) to the cells affected little the fluorescence of FluoZin, confirming that Cd(2+) was the main ion increasing intracellular fluorescence. Ca(2+) channels blockers (nimodipine and verapamil) decreased Cd(2+) influx as well as vanadate, a Ca(2+)-ATPase blocker. Chelating intracellular Ca(2+) (BAPTA) decreased Cd(2+) influx in gill cells, while increasing intracellular Ca(2+) (caffeine) augmented Cd influx. Cd(2+) and ATP added at different temporal conditions were not effective at increasing intracellular Cd(2+) accumulation. Ouabain (Na(+)/K(+)-ATPase inhibitor) increased Cd(2+) influx probably through a change in intracellular Na and/or a change in cell membrane potential. Routes of Cd(2+) influx, a non-essential metal, through the gill cell plasma membrane of crabs are suggested. PMID:25456216

  14. Biomemetic pumping by gill plate arrays: Reynolds number effects in mayfly nymphs

    NASA Astrophysics Data System (ADS)

    Sensenig, Andrew; Shultz, Jeffrey; Kiger, Ken

    2007-11-01

    Mayfly nymphs are entirely aquatic and must alter behavior and metabolism to accommodate changes in ambient dissolved oxygen levels. Many species can generate a ventilation current to compensate for low oxygen levels by beating two linear arrays of plate-like gills that line the lateral edge of the abdomen. The characteristic Reynolds number associated with the gill motion changes with animal size, varying over a span of Re = 5 to 100 depending on age and species. Thus mayflies provide a novel system model for studying ontological changes in pumping mechanisms associated with transitions from a viscous- to inertia-dominated flow. Indeed, observation of other animals and theoretical analysis[1] indicate that a bifurcation should exist for inertial thrust generation by a reciprocal flapper for Reynolds numbers on the order of 10-20. In the ongoing work, the gill kinematics and resulting fluid motion is recorded experimentally through the use of high-speed stereo imaging and cinematographic planar PIV. Results show that the gills transition from a strongly asymmetric motion at Re=5 to a more reciprocal motion by Re=21. Details of the hydrodynamic mechanisms and pumping effectiveness will be discussed. [1] Childress, S. & Dudley, R. (2004), J. Fluid Mech. 498, 257--288.

  15. We Walked Very Warily. A History of Women at McGill.

    ERIC Educational Resources Information Center

    Gillett, Margaret

    Nineteenth-century assumptions about the nature of women, her educability, her role in society, and debates about coeducation are examined in this record of the efforts of the first women students to gain entrance in McGill University in Canada. The introduction offers historical background, ideas of women, and the opening of higher education to…

  16. RESPIRATORY-CARDIOVASCULAR PHYSIOLOGY AND CHLOROETHANE GILL FLUX IN THE CHANNEL CATFISH ICTALRUS PUNCTATUS

    EPA Science Inventory

    A fish respirometer-metabolism chamber was used to obtain in ivo respiratory-cardiovascular and chloroethane gill flux data on transected channel catfish (Ictalrus punctatus). ethods used for spinal transection, attachment of an oral membrane (respiratory mask), placement and att...

  17. Evolution of gilled mushrooms and puffballs inferred from ribosomal DNA sequences

    PubMed Central

    Hibbett, David S.; Pine, Elizabeth M.; Langer, Ewald; Langer, Gitta; Donoghue, Michael J.

    1997-01-01

    Homobasidiomycete fungi display many complex fruiting body morphologies, including mushrooms and puffballs, but their anatomical simplicity has confounded efforts to understand the evolution of these forms. We performed a comprehensive phylogenetic analysis of homobasidiomycetes, using sequences from nuclear and mitochondrial ribosomal DNA, with an emphasis on understanding evolutionary relationships of gilled mushrooms and puffballs. Parsimony-based optimization of character states on our phylogenetic trees suggested that strikingly similar gilled mushrooms evolved at least six times, from morphologically diverse precursors. Approximately 87% of gilled mushrooms are in a single lineage, which we call the “euagarics.” Recently discovered 90 million-year-old fossil mushrooms are probably euagarics, suggesting that (i) the origin of this clade must have occurred no later than the mid-Cretaceous and (ii) the gilled mushroom morphology has been maintained in certain lineages for tens of millions of years. Puffballs and other forms with enclosed spore-bearing structures (Gasteromycetes) evolved at least four times. Derivation of Gasteromycetes from forms with exposed spore-bearing structures (Hymenomycetes) is correlated with repeated loss of forcible spore discharge (ballistospory). Diverse fruiting body forms and spore dispersal mechanisms have evolved among Gasteromycetes. Nevertheless, it appears that Hymenomycetes have never been secondarily derived from Gasteromycetes, which suggests that the loss of ballistospory has constrained evolution in these lineages. PMID:9342352

  18. Structural Changes in the Somatosensory System Correlate with Tic Severity in Gilles de la Tourette Syndrome

    ERIC Educational Resources Information Center

    Thomalla, Gotz; Siebner, Hartwig R.; Jonas, Melanie; Baumer, Tobias; Biermann-Ruben, Katja; Hummel, Friedhelm; Gerloff, Christian; Muller-Vahl, Kirsten; Schnitzler, Alfons; Orth, Michael; Munchau, Alexander

    2009-01-01

    Gilles de la Tourette syndrome (GTS) is a neuropsychiatric disorder characterized by multiple motor and vocal tics. Previous structural MRI studies have identified regional abnormalities in grey matter, especially in the basal ganglia. These findings are consistent with the assumption of alterations in cortico-striato-thalamo-cortical circuits and…

  19. RESPIRATORY-CARDIOVASCULAR PHYSIOLOGY AND XENOBIOTIC GILL FLUX IN THE LAKE TROUT (SALVELINUS NAMAYCUSH)

    EPA Science Inventory

    An in vivo respirometer-metabolism chamber was used to obtain respiratory-cardiovascular physiology under normoxic and hypoxic conditions, and xenobiotic gill absorption (flux) data on adult lake trout (Salvelinus namaycush) over a 48-h exposure period at 11? 1?C.

  20. Nonlethal gill biopsy does not affect juvenile chinook salmon implanted with radio transmitters

    USGS Publications Warehouse

    Martinelli-Liedtke, T. L.; Shively, R.S.; Holmberg, G.S.; Sheer, M.B.; Schrock, R.M.

    1999-01-01

    Using gastric and surgical transmitter implantation, we compared radio-tagged juvenile chinook salmon Oncorhynchus tshawytscha (T(O)) with tagged fish also having a gill biopsy (T(B)) to determine biopsy effects on fish implanted with radio transmitters. We found no evidence during the 21-d period to suggest that a gill biopsy reduced survival, growth, or gross condition of the tagged-biopsy group, regardless of transmitter implantation technique. We recorded 100% survival of all treatment groups. Relative growth rates of T(O) and T(B) fish did not differ significantly. Leukocrit and lysozyme levels were not significantly different among groups, suggesting that no signs of infection were present. Our findings suggest that small chinook salmon can tolerate the combination of transmitter implantation and gill biopsy without compromising condition relative to fish receiving only the transmitter. We believe a gill biopsy can be used in field telemetry studies, especially when physiological data are needed in addition to behavioral data.

  1. Histological evaluation of sodium percarbonate exposure on the gills of rainbow trout.

    PubMed

    Forwood, James M; Harris, James O; Landos, Matt; Deveney, Marty R

    2015-06-01

    Ichthyophthirius multifiliis is a recurring problem in Australian rainbow trout Oncorhynchus mykiss farms and requires strategically timed, repeat treatments for effective management. Sodium percarbonate (SPC) is permitted for use in Australia, with host safety margins based on the toxicity of acute exposures to hydrogen peroxide (HP), the active product released when SPC is added to water. The effects of exposure to HP released by SPC, of repeated doses and of doses exceeding 100 mg l-1 on rainbow trout are unknown. We exposed juvenile rainbow trout (mean weight: 30.5 ± 9 g) to repeated doses of 50, 150 and 250 mg l-1 SPC for 1 h on Days 1, 2, 7 and 8 of a treatment regime. The effect of SPC was assessed by histological evaluation of structural changes in gill tissue. Survival was 100% in all groups, but some fish exposed to 250 mg l-1 SPC displayed impaired swimming performance, and on Day 9 after the final treatment, oedema was present in 9.8% of lamella, which was significantly higher than the mean occurrence of 1.7, 4.2 and 1.3% in fish treated with 0, 50 and 150 mg l-1 SPC, respectively. These changes resolved within 24 h of the cessation of treatment. We conclude that SPC is safe to use on rainbow trout in doses of ≤150 mg l-1 at 17°C, however caution is advised at doses approaching 250 mg l-1. Water temperature, fish age, fish size and maturity, intensity of parasite infection and stocking density could alter the sensitivity of rainbow trout to SPC treatments. PMID:26036833

  2. Environmental monitoring of urban streams using a primary fish gill cell culture system (FIGCS).

    PubMed

    Schnell, Sabine; Bawa-Allah, Kafilat; Otitoloju, Adebayo; Hogstrand, Christer; Miller, Thomas H; Barron, Leon P; Bury, Nic R

    2015-10-01

    The primary fish gill cell culture system (FIGCS) is an in vitro technique which has the potential to replace animals in whole effluent toxicity tests. In the current study FIGCS were transported into the field and exposed to filtered (0.2μm) river water for 24h from 4 sites, on 2 different sampling dates. Sites 1 and 2 are situated in an urban catchment (River Wandle, London, UK) with site 1 downstream of a sewage treatment work; site 3 is located in a suburban park (River Cray, Kent, UK), and site 4 is more rural (River Darent, Kent, UK). The change in transepithelial electrical resistance (TER), the expression of the metal responsive genes metallothionein A (mta) and B (mtb), cytochrome P450 1A1 (cyp1a1) and 3A27 (cyp3a27), involved in phase 1 metabolism, were assessed following exposure to sample water for 24h. TER was comparable between FIGCS exposed to 0.2μm filtered river water and those exposed to synthetic moderately soft water for 24h. During the first sampling time, there was an increase in mta, cyp1a1 and cyp3a27 gene expression in epithelium exposed to water from sites 1 and 2, and during the second sampling period an increase in cyp3a27 gene expression at sites 1 and 4. Urban river water is a complex mixture of contaminants (e.g., metals, pesticides, pharmaceuticals and polyaromatic hydrocarbons) and the increase in the expression of genes encoding mta, cyp1a1 and cyp3a27 in FIGCS is indicative of the presence of biologically active pollutants. PMID:26093110

  3. Effects of titanium dioxide nanoparticle exposure in Mytilus galloprovincialis gills and digestive gland.

    PubMed

    Gornati, Rosalba; Longo, Arturo; Rossi, Federica; Maisano, Maria; Sabatino, Giuseppe; Mauceri, Angela; Bernardini, Giovanni; Fasulo, Salvatore

    2016-08-01

    Despite the wide use of nanoscale materials in several fields, some aspects of the nanoparticle behavior have to be still investigated. In this work, we faced the aspect of environmental effects of increasing concentrations of TiO2NPs using the Mytilus galloprovincialis as an animal model and carrying out a multidisciplinary approach to better explain the results. Bioaccumulation suggested that the gills and digestive gland are the most sensitive organs to TiO2NP exposure. Histological observations have evidenced an altered tissue organization and a consistent infiltration of hemocytes, as a consequence of the immune system activation, even though an increase in lipid peroxidation is uncertain and DNA damage became relevant only at high exposure dose (10 mg/L) or for longer exposure time (96 h). However, the over expression of SOD1 mRNA strengthen the concept that the toxicity of TiO2NPs could occur indirectly by ROS production. TEM analysis showed the presence of multilamellar bodies, RER fragmentation, and cytoplasmic vacuolization within relevant presence of dense granules, residual bodies, and lipid inclusions. These findings support the evidence of an initial inflammatory response by the cells of the target organs leading to apoptosis. In conclusion, we can state that certainly the exposure to TiO2NPs has affected our animal model from cellular to molecular levels. Interestingly, the same responses are caused by lower TiO2NP concentration and longer exposure time as well as higher doses and shorter exposure. We do not know if some of the conditions detected are reversible, then further studies are required to clarify this aspect. PMID:26846715

  4. Calcium transport and homeostasis in gill cells of a freshwater crab Dilocarcinus pagei.

    PubMed

    Granado e Sá, Marina; Baptista, B B; Farah, L S; Leite, V P; Zanotto, F P

    2010-03-01

    Crustaceans present a very interesting model system to study the process of calcification and calcium (Ca(2+)) transport because of molting-related events and the deposition of CaCO(3) in the new exoskeleton. Dilocarcinus pagei, a freshwater crab endemic to Brazil, was studied to understand Ca(2+) transport in whole gill cells using a fluorescent probe. Cells were dissociated, all of the gill cell types were loaded with fluo-3 and intracellular Ca(2+) change was monitored by adding Ca as CaCl(2) (0, 0.1, 0.25, 0.50, 1.0 and 5 mM), with a series of different inhibitors. For control gill cells, Ca(2+) transport followed Michaelis-Menten kinetics with K(m) = 0.42 +/- 0.04 mM and V(max) = 0.50 +/- 0.02 microM (Ca(2+) change x initial intracellular Ca(-1) x 180 s(-1); N = 14, r (2) = 0.99). Verapamil (a Ca(2+) channel inhibitor) and amiloride (a Na(+)/Ca(2+) exchanger [NCX] inhibitor) completely reduced intracellular Ca(2+) transport, while nifedipine, another Ca(2+) channel inhibitor, did not. Vanadate, a plasma membrane Ca(2+)-ATPase inhibitor (PMCA), increased intracellular Ca(2+) in gill cells through a decrease in the efflux of Ca(2+). Ouabain increased intracellular Ca(2+), similar to the effect of KB-R, a specific NCX inhibitor for Ca(2+) in the influx mode. Alterations in extracellular [Na] in the saline did not affect intracellular Ca(2+) transport. Caffeine, responsible for inducing Ca release from sarcoplasmic reticulum in vertebrate muscle, increased intracellular Ca(2+) compared to control, suggesting an effect of this inhibitor in gill epithelial cells of Dilocarcinus pagei, probably through release of intracellular stores. We also demonstrate here that intracellular Ca(2+) in gill cells of Dilocarcinus pagei was kept relatively constant in face of an extracellular Ca concentration of 50-fold, suggesting that crustaceans are able to display Ca(2+) homeostasis through various Ca(2+) intracellular sequestration mechanisms and/or plasma membrane Ca(2+) influx

  5. Evaporites, surface roughness, and inundation in a playa dust source; implications of surface composition for erodibility

    NASA Astrophysics Data System (ADS)

    Tollerud, H.; Fantle, M.

    2013-12-01

    An understanding of fundamental controls on dust emission is critical in order to predict and model geochemical fluxes in the Earth system. Crucial parameters for dust emission include surface properties such as roughness, strength, and composition, which affect the erodibility of surface sediments. Accordingly, knowledge of the processes that govern surface properties is vital for predicting geochemical dust fluxes. In this study, we examine the spatial distribution of mineralogy within a playa dust source (Black Rock Desert, NV, USA) and its association with the spatial distribution of annual inundation, and employ a numerical model to assess the importance of transport by inundation for producing the distribution of mineralogy that we observe. Additionally, we experimentally investigate the effect of evaporite mineralogy on the development of surface roughness in a playa analog surface. We hypothesize that evaporite minerals in playa surface crusts reduce erodibility by contributing to sediment aggregation, promoting smoothing of the surface and a decrease in the availability of particles for saltation. Heterogeneity in surface mineralogy will then affect erodibility. Thus, it is useful to identify controls on the distribution of mineralogy (specifically evaporites) across a playa dust source. In particular, a connection between inundation and surface heterogeneity suggests that inundation could influence erodibility. Semi-quantitative X-ray diffraction analysis of surface sediments from the Black Rock Desert shows that evaporite content is variable; halite content varies from 0-40 wt%, and calcite from 2-15 wt%, with average sediment compositions of 30% quartz, 45% clay, and 10% plagioclase. Average calcite content is lower (7.6%) for sites within the inundated area of the previous year's playa lake (detected using MODIS satellite imagery; band 6, 1640 nm) than for sites outside this area (average calcite content 9.5%). Sites inundated the previous year are

  6. Loess Plateau check dams can potentially sequester eroded soil organic carbon

    NASA Astrophysics Data System (ADS)

    Zhang, Haicheng; Liu, Shuguang; Yuan, Wenping; Dong, Wenjie; Xia, Jiangzhou; Cao, Yaojun; Jia, Yanwei

    2016-06-01

    Check dams are special soil and water conservation structures in the Loess Plateau, China. They play an important role in intercepting sediments and soil organic carbon (SOC). However, the decomposition of intercepted SOC and the environmental regulations at check dams have not been investigated. We conducted several paired field experiments at both check dams and slope lands in the Yanhe Watershed of the Loess Plateau to examine the characteristics of SOC decomposition at check dams. On average, the SOC mineralization rate in slope lands was approximately three times higher than in check dams. Increased soil moisture and compaction in check dams can constrain carbon mineralization by limiting the oxygen availability of SOC and can isolate substrate carbon from heterotrophic microorganisms. Our results indicate that check dams display a considerable potential for eroded SOC sequestration via reducing the soil respiration rate and highlight the important implications of lateral carbon redistribution and human engineering projects when estimating regional or global ecosystem carbon cycles.

  7. Changes in barrier health status of the gill for grass carp (Ctenopharyngodon idella) during valine deficiency: Regulation of tight junction protein transcript, antioxidant status and apoptosis-related gene expression.

    PubMed

    Feng, Lin; Luo, Jian-Bo; Jiang, Wei-Dan; Liu, Yang; Wu, Pei; Jiang, Jun; Kuang, Sheng-Yao; Tang, Ling; Zhang, Yong-An; Zhou, Xiao-Qiu

    2015-08-01

    This study investigated the effects of dietary valine on tight junction protein transcription, antioxidant status and apoptosis on grass carp gills (Ctenopharyngodon idella). Fish were fed six different experimental diets containing graded levels of valine (4.3, 8.0, 10.6, 13.1, 16.7, 19.1 g/kg). The results indicated that valine deficiency decreased Claudin b, Claudin 3, Occludin and ZO-1 transcription and increased Claudin 15 expression in the fish gill (P < 0.05). These effects were partly due to the down-regulation of interleukin 10 (IL-10), transforming growth factor β1 (TGF-β1) and IκB α and the up-regulation of relative mRNA expression of interleukin 1β (IL-1β), interleukin 8 (IL-8), tumor necrosis factor-α (TNF-α) and nuclear factor κB P65 (NF-κB P65) (P < 0.05). However, valine deficiency and valine supplementation did not have a significant effect on Claudin c and Claudin 12 expression in grass carp gills (P > 0.05). Valine deficiency also disrupted antioxidant status in the gill by decreasing anti-superoxide radicals and hydroxyl radical capacity, glutathione contents and the activities and mRNA levels of Cu/Zn superoxide dismutase (SOD1), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) (P < 0.05). These results may be ascribed to the down-regulation of NF-E2-related factor 2 (Nrf2), target of rapamycin (TOR) and ribosomal protein S6 kinase 1 (S6K1) and the up-regulation of Kelch-like-ECH-associated protein 1 (Keap1) (P < 0.05). Additionally, valine deficiency induced DNA fragmentation via the up-regulation of Caspase 3, Caspase 8 and Caspase 9 expressions (P < 0.05). These results may be ascribed to the improvement in ROS levels in the fish gill (P < 0.05). Taken together, the results showed that valine deficiency impaired the structural integrity of fish gill by disrupted fish antioxidant defenses and regulating the expression of tight junction protein, cytokines, antioxidant

  8. Topographic roughness as a signature of the emergence of bedrock in eroding landscapes

    NASA Astrophysics Data System (ADS)

    Milodowski, D. T.; Mudd, S. M.; Mitchard, E. T. A.

    2015-10-01

    Rock is exposed at the Earth surface when rates of erosion locally exceed rates of soil production. The thinning of soils and emergence of bedrock has implications spanning geomorphology, ecology and hydrology. Soil-mantled hillslopes are typically shaped by diffusion-like sediment transport processes that act to smooth topography through time, generating the familiar smooth, convex hillslope profiles that are common in low relief landscapes. Other processes, however, can roughen the landscape. Bedrock emergence can produce rough terrain; in this contribution we exploit the contrast between rough patches of bedrock outcrop and smooth, diffusion-dominated soil to detect bedrock outcrops. Specifically, we demonstrate that the local variability of surface normal vectors, measured from 1 m resolution airborne LiDAR data, can be used as a topographic signature to identify areas within landscapes where rock exposure is present. We then use this roughness metric to investigate the transition from soil-mantled to bedrock hillslopes as erosion rates increase in two transient landscapes, Bald Rock Basin, which drains into the Middle Fork Feather River, California, and Harrington Creek, a tributary of the Salmon River, Idaho. Rather than being abrupt, as predicted by traditional soil production models, in both cases the transition from fully soil-mantled to bedrock hillslopes is gradual and spatially heterogeneous, with rapidly eroding hillslopes supporting a patchwork of bedrock and soil that is well documented by changes in topographic roughness, highlighting the utility of this metric for testing hypotheses concerning the emergence of bedrock and adding to a growing body of evidence that indicates the persistence of partial soil mantles in steep, rapidly eroding landscapes.

  9. Crop Performance and Soil Properties in Two Artificially-Eroded Soils in North-Central Alberta

    SciTech Connect

    Izaurralde, R Cesar C.; Malhi, S. S.; Nyborg, M.; Solberg, E. D.; Quiroga Jakas, Maria C.

    2006-09-01

    Field experiments were conducted from 1991 to 1995 at Josephburg (Orthic Black Chernozem, Typic Cryoboroll) and Cooking Lake (Orthic Gray Luvisol, Typic Cryoboralf), Alberta, to determine impact of topsoil removal on selected soil properties, N-mineralization potential and crop yield, and effectiveness of various amendments for restoring the productivity of eroded soils. The simulated-erosion levels were established in the autumn of 1990 by removing 20 cm topsoil in 5-cm depth increments. The four amendments were: control, addition of 5 cm of topsoil, fertilizers to supply 100 kg N ha-1 and 20 kg P ha-1, and cattle manure at 75 Mg ha-1. Topsoil and manure were applied once in the autumn of 1990, while fertilizers were applied annually from 1991 to 1995. Available N and P, total C, N and P, and N-mineralization potential decreased, while bulk density increased with increasing depth of topsoil removal. Tiller number, plant height, spike density, thousand kernel weight, and leaf area index decreased with simulated erosion. Grain yield reductions due to simulated soil erosion were either linear or curvilinear functions of nutrient removal. Application of N and P fertilizers and manure improved grain yield and reduced the impact of yield loss due to erosion. Return of 5 cm of topsoil also increased grain yield, but to a lesser extent than manure or fertilizers. Grain yields were maximized when fertilizers were also applied to organic amendment treatments. In conclusion, the findings suggest the importance of integrated use of organic amendments and chemical fertilizers for best crop yields on severely-eroded soils.

  10. Restoration of drastically eroded land using coal fly ash and poultry biosolid.

    PubMed

    Punshon, Tracy; Adriano, Domy C; Weber, John T

    2002-09-16

    A 3-year field study was conducted at a 12 ha soil-borrow area adjacent to the Columbia Metropolitan Airport, South Carolina to investigate the restorative effects of co-application of coal fly ash (FA) and a poultry biosolid (PB). FA was applied at 0, 22, 280, 560 and 1120 Mg (tonne) ha(-1), and PB at 5 and 10 Mg ha(-1). The area was seeded with erosion-control species Atlantic Coastal panic grass (Panicum amarum var amarum L.), sericea (Lespedeza cuneata var. appalow [Dumont] G. Don.) and weeping love grass (Eragrostis curvula Wolf.). Plant biomass and elemental composition were analyzed in sequential harvests. Soil and groundwater quality characteristics including pH, EC and elemental composition were also monitored throughout the study. In addition, the effect of amendments on the water holding capacity and bulk density of the soil was investigated. Amendment addition significantly increased plant biomass production by a maximum of 26% using 1120 Mg ha(-1) FA and 10 Mg ha(-1) PB. Application of the highest rate of FA significantly increased the plant tissue concentrations of Mn, As, Se and B. Soil pH was initially increased from 4.6 to 6.1 by amendments. Soil salinity was increased in the initial year only. Amended soils had higher concentrations of Ca, Mg, P and K, higher organic matter content and water holding capacity than unamended soil. Concentrations of plant-essential trace elements (B, Cu and Zn) that were marginally deficient in the unamended eroded soil increased to within typical soil concentrations following amendment with FA and PB. Groundwater quality was unaffected throughout the study. The co-application of FA and PB successfully promoted the revegetation of the eroded borrow area with no apparent adverse environmental side effects. PMID:12398338

  11. Variability of rock erodibility in bedrock-floored stream channels based on abrasion mill experiments

    NASA Astrophysics Data System (ADS)

    Small, Eric E.; Blom, Tevis; Hancock, Gregory S.; Hynek, Brian M.; Wobus, Cameron W.

    2015-08-01

    We quantify variations in rock erodibility, Kr, within channel cross sections using laboratory abrasion mill experiments on bedrock surfaces extracted from streams with sandstone bedrock in Utah and basaltic bedrock in the Hawaiian Islands. Samples were taken from the thalweg and channel margins, the latter at a height that is inundated annually. For each sample, a sequence of abrasion mill experiments was completed to quantify variations in erosion rate with erosion depth. Erosion rate data from these experiments shows two things. First, the erosion rate from channel margin samples is greater than for thalweg samples, with the greatest difference observed for the rock surface that was exposed in the stream channel. Second, erosion rate decreases with depth beneath the original rock surface, by an order of magnitude in most cases. The erosion rate becomes steady at depths of 1-3 mm for channel margin samples and 0.1-0.4 mm for thalweg samples. Because only rock properties and microtopography vary throughout the sequence of mill experiments, these results suggest that Kr of the bedrock surface exposed in stream channels is higher at the margins than near the channel center and that Kr decreases over depths of ~1 mm. The simplest explanation for these patterns is that Kr is enhanced, at the bedrock surface and along the channel margins, due to the effects of weathering on rock strength and surface roughness. We hypothesize that a balance exists between weathering-enhanced erodibility and episodic incision to allow channel margins to lower at rates similar to the thalweg.

  12. Sustainable soil management practices and quality of potato grown on erodible lands.

    PubMed

    Antonious, G F; Lee, C M; Snyder, J C

    2001-07-01

    Land productivity can decline when top soil is lost. In Kentucky, limited resource farmers often produce vegetable crops on erodible lands. The objectives of this study were 1) to quantify the impact of three soil management practices (SMPs) on quantity of potato produced on erodible land, 2) to evaluate the impact of pyrethrin and azadirachtin insecticides on potato tuber quality, and 3) to assess the impact of yard waste compost on the chemical composition (ascorbic acid, free sugars, phenol contents) of potato tubers. Potatoes (Solanum tuberosum L. cv. Kennebec) were grown in a silty loam soil of 10% slope. Plots (n= 18) were 3.7 m wide and 22 m long (10% slope), with metal borders of 20 cm above ground level. Two botanical insecticides, Multi-Purpose Insecticide (containing pyrethrin 0.2%) and Neemix 4EC (containing 0.25% azadirachtin) were sprayed twice on potato foliage during each of two growing seasons (1997 and 1999) at the recommended rates of 6 lbs and 2 gallons.acre(-1), respectively. The SMPs were tall fescue strips (FS) intercropped between each two potato rows, soil mixed with yard waste compost (COM) and no-mulch (NM) treatment (roto-tilled bare soil). The experimental designwas a 2 x 3 x 3 factorial with main factors of two insecticides and three SMPs replicated three times. Average potato yield was lowest in NM and FS and highest in COM treatments. Yield obtained from the bottom of the plots was greater than that obtained from the top of plots. Tuber defects (rot, scab, sun green, hollow heart, necrosis, and vascular discoloration) were significantly different between the two growing seasons. The two insecticidal treatments did not have much influence on potato yield or tuber defects. Tubers obtained from tall fescue treatments had low levels of ascorbic acid and reducing sugars compared to compost treatments. PMID:11495021

  13. Intrusion level of granitic massifs along the Hercynian belt: balancing the eroded crust

    NASA Astrophysics Data System (ADS)

    Vigneresse, J. L.

    1999-06-01

    Hercynian granitoid intrusions form a long (3200 km) belt comparable in size to other batholiths in the world. Six massifs have been selected which encompass Cabeza de Araya (Extremadura, Spain), Guitiriz (Galicia, Spain), Pontivy and Mortagne (Brittany, France), La Marche (Massif Central, France) and Fichtelgebirge (Bavaria, Germany). Detailed gravity surveys over these massifs and subsequent inversion provide their shape at depth. Correlation of the deeper zones with internal structures determine the place of the root zones. The shape of the massifs is examined along the strike of the chain. The emplacement of individual massifs is controlled by local tectonics. Most granites are not deeply rooted, but one massif (Cabeza de Araya, Spain) shows a root zone presently as deep as 14 km. Most have about half of their volume in the first 3 km below the present surface. Estimates of the magma volume transferred result in 1500 km 3 issued from one specific feeder, yielding a total of 70,000 km 3 of magma intruded all along the chain. The depth of emplacement of the granitic massifs does not show any significant trend along the strike of the chain. The shallower massifs in the French Massif Central correspond to more deeply eroded areas in the center of the chain. Their root zone, as well as the change in the dip of the walls, are presently observed at depths ranging between 4 and 6 km in Hercynian granites. Both variations are interpreted as being related to the brittle/ductile transition at the time of emplacement. Gross thermal considerations place the transition at its former place during magma emplacement, indicating that the upper crust has not been eroded by more than 6-8 km. This estimate severely contrasts with models involving a doubled crust.

  14. Measuring Carbon and Nitrogen Eroded From Burned Forests In The Western U.S

    NASA Astrophysics Data System (ADS)

    Pierson, D. N.; Robichaud, P. R.; Rhoades, C.

    2013-12-01

    Post-wildfire upland landscapes and downstream aquatic resources are influenced by carbon (C) and nitrogen (N) losses due to soil erosion. As opposed to bulk soil erosion, few studies have quantified C and N losses after severe wildfire. We measured erosion of C and N for four to six years following eight wildfires in the western U.S. and compared C and N losses from untreated, burned hillslopes and small catchments with those from adjacent areas that received various erosion mitigation treatments. Losses of C, N and sediment were greatest the first two years and declined in subsequent years. Cumulative losses from untreated, burned areas were 16 - 4,700 kg C/ha and 0.7 - 185 kg N/ha over the study period. Individual storm events were responsible for > 50% of the total C and N lost. Across wildfire locations, median sediment C and N concentration ranged from 0.11 - 0.36 %N and 2.3 - 9.8 %C. Post-fire erosion control treatments reduced C, N and sediment losses by 65-75% compared to untreated areas and generally increased the concentrations of C and N in eroded material. The total C and N lost in post-fire erosion was < 20% of the estimated amount lost from organic and mineral soil layers during combustion and < 5% of the estimated amount remaining in mineral soils after combustion. The additional N lost with soil erosion is unlikely to impair the productivity of recovering forests, but the eroded N may have consequences on downstream water quality and aquatic habitat.

  15. Regulation of gill claudin paralogs by salinity, cortisol and prolactin in Mozambique tilapia (Oreochromis mossambicus).

    PubMed

    Tipsmark, Christian K; Breves, Jason P; Rabeneck, D Brett; Trubitt, Rebecca T; Lerner, Darren T; Grau, E Gordon

    2016-09-01

    In euryhaline teleosts, reorganization of gill tight junctions during salinity acclimation involves dynamic expression of specific claudin (Cldn) paralogs. We identified four transcripts encoding Cldn tight junction proteins in the tilapia gill transcriptome: cldn10c, cldn10e, cldn28a and cldn30. A tissue distribution experiment found cldn10c and cldn10e expression levels in the gill to be 100-fold higher than any other tissues examined. cldn28a and cldn30 levels in the gill were 10-fold greater than levels in other tissues. Expression of these genes in Mozambique tilapia was examined during acclimation to fresh water (FW), seawater (SW), and in response to hormone treatments. Transfer of tilapia from FW to SW elevated cldn10c and cldn10e, while cldn28a and cldn30 were stimulated following transfer from SW to FW. In hypophysectomized tilapia transferred to FW, pituitary extirpation induced reduced expression of cldn10c, cldn10e and cldn28a; these effects were mitigated equally by either prolactin or cortisol replacement. In vitro experiments with gill filaments showed that cortisol stimulated expression of all four cldns examined, suggesting a direct action of cortisol in situ. Our data indicate that elevated cldn10c and cldn10e expression is important during acclimation of tilapia to SW possibly by conferring ion specific paracellular permeability. On the other hand, expression of cldn28a and cldn30 appears to contribute to reorganization of branchial epithelium during FW acclimation. Hormone treatment experiments showed that particular FW- and SW-induced cldns are controlled by cortisol and prolactin. PMID:27210417

  16. Histopathological changes in gill and liver of Capoeta capoeta living in the Karasu River, Erzurum.

    PubMed

    Dane, Hatice; Şişman, Turgay

    2015-07-01

    The contamination of surface waters by different pollutants is an important problem worldwide. In this study, the histopathological effects of water pollution were investigated on freshwater fish species Capoeta capoeta caught from the Karasu River. Fish were caught at three different sites in the Karasu River, namely, Aşkale, Dumlu, and Serçeme. The histological changes in gill and liver of fish were detected microscopically and evaluated with quantitative analyses. In addition, heavy metals have also been determined in surface water samples from these sites. Results showed that the Aşkale site was polluted by different kinds of heavy metals. In Aşkale site, some heavy metals such as Cd, Al, As, Pb, and Mn levels were mostly detected at concentrations above than the accepted values by the Turkish Standards Institute. The presence of gill and liver histological alterations were assessed by the degree of tissue change (DTC). In gill filaments, hypertrophy and hyperplasia of the gill epithelium, lamellar epithelial lifting, lamellae shortening, vasodilatation, lamellar disorganization, blood congestion, fusion, and aneurysm were observed. In the liver, the changes included an increase in the number and size of melanomacrophage aggregates, nonhomogenous parenchyma, proliferation of the hepatopancreas, sinusoidal dilatation, vacuolization, hypertrophy of the hepatocytes, congestion and degeneration of central vein, blood congestion, pyknotic nucleus, focal necrosis, and hepatic granuloma. The histological lesions were comparatively most severe in liver. The DTC means were varied from slight to moderate of gill and moderate to severe of liver tissue in the Aşkale site, thus the site is considered to be of low quality. Some pathological alterations were observed in the Serçeme site, although their distribution was lower than sites Dumlu and especially Aşkale. The least DTC means of the Serçeme site demonstrated their good environmental quality. The results

  17. Identification of Methanotrophic Lipid Biomarkers in Cold-Seep Mussel Gills: Chemical and Isotopic Analysis

    NASA Technical Reports Server (NTRS)

    Jahnke, Linda L.; Summons, Roger E.; Dowling, Lesley M.; Zahiralis, Karen D.

    1995-01-01

    A lipid analysis of the tissues of a cold-seep mytilid mussel collected from the Louisiana slope of the Gulf of Mexico was used in conjunction with a compound-specific isotope analysis to demonstrate the presence of methanotrophic symbionts in the mussel gill tissue and to demonstrate the host's dependence on bacterially synthesized metabolic intermediates. The gill tissue contained large amounts of group-specific methanotrophic biomarkers, bacteriohopanoids, 4-methylsterols, lipopolysaccharide-associated hydroxy fatty acids, and type I-specific 16:1 fatty acid isomers with bond positions at delta-8, delta-10, and delta-ll. Only small amounts of these compounds were detected in the mantle or other tissues of the host animal. A variety of cholesterol and 4-methylsterol isomers were identified as both free and steryl esters, and the sterol double bond positions suggested that the major bacterially derived gill sterol(11.0% 4(alpha)-methyl-cholesta-8(14), 24-dien-3(beta)-ol) was converted to host cholesterol (64.2% of the gill sterol was cholest-5-en-3(beta)-ol). The stable carbon isotope values for gill and mantle preparations were, respectively, -59.0 and -60.4 per thousand for total tissue, -60.6 and -62.4 per thousand for total lipids, -60.2 and -63.9 per thousand for phospholipid fatty acids, and -71.8 and -73.8 per thousand for sterols. These stable carbon isotope values revealed that the relative fractionation pattern was similar to the patterns obtained in pure culture experiments with methanotrophic bacteria further supporting the conversion of the bacterial methyl-sterol pool.

  18. Copper binding affinity of rainbow trout (Oncorhynchus mykiss) and brook trout (Salvelinus fontinalis) gills: Implications for assessing bioavailable metal

    SciTech Connect

    MacRae, R.K.; Smith, D.E.; Swoboda-Colberg, N.; Meyer, J.S.; Bergman, H.L. . Dept. of Zoology and Physiology)

    1999-06-01

    In this study, the authors determined the conditional stability constant (log K[prime]) of copper for the gills of rainbow trout (Oncorhynchus mykiss; RBT) and brook trout (Salvelinus fontinalis; BT). Using toxicity-based complexation bioassays, which measure the effect of competing organic ligands on copper toxicity, the RBT gill copper log K[prime] range was 6.4 to 7.2. Using a Scatchard analysis of gill Cu accumulation, the RBT log K[prime] was 7.50 and the BT log K[prime] was 7.25. The close agreement in RBT log K[prime] values between these two methods suggests that measurement of gill copper accumulation is an acceptable alternative for determining a toxicity-based gill copper binding affinity. The results also suggest that there is either a single gill copper binding component or, more realistically, multiple components with similar binding properties that function collectively to define a single toxicologically relevant copper conditional stability constant. These results suggest analytical approaches to measuring bioavailable metal concentrations, such as geochemical modeling where biological ligands are included in speciation calculations, may adequately simulate complex biological ligands. A method to convert gill copper accumulation to a bioavailable water criterion is also discussed.

  19. A kinetic study of the gill (Na+, K+)-ATPase, and its role in ammonia excretion in the intertidal hermit crab, Clibanarius vittatus.

    PubMed

    Gonçalves, Rúbia R; Masui, Douglas C; McNamara, John C; Mantelatto, Fernando L M; Garçon, Daniela P; Furriel, Rosa P M; Leone, Francisco A

    2006-11-01

    To better comprehend the role of gill ion regulatory mechanisms, the modulation by Na(+), K(+), NH(4)(+) and ATP of (Na(+), K(+))-ATPase activity was examined in a posterior gill microsomal fraction from the hermit crab, Clibanarius vittatus. Under saturating Mg(2+), Na(+) and K(+) concentrations, two well-defined ATP hydrolyzing sites were revealed. ATP was hydrolyzed at the high-affinity sites at a maximum rate of V=19.1+/-0.8 U mg(-1) and K(0.5)=63.8+/-2.9 nmol L(-1), obeying cooperative kinetics (n(H)=1.9); at the low-affinity sites, hydrolysis obeyed Michaelis-Menten kinetics with K(M)=44.1+/-2.6 mumol L(-1) and V=123.5+/-6.1 U mg(-1). Stimulation by Na(+) (V=149.0+/-7.4 U mg(-1); K(M)=7.4+/-0.4 mmol L(-1)), Mg(2+) (V=132.0+/-5.3 U mg(-1); K(0.5)=0.36+/-0.02 mmol L(-1)), NH(4)(+) (V=245.6+/-9.8 U mg(-1); K(M)=4.5+/-0.2 mmol L(-1)) and K(+) (V=140.0+/-4.9 U mg(-1); K(M)=1.5+/-0.1 mmol L(-1)) followed a single saturation curve and, except for Mg(2+), obeyed Michaelis-Menten kinetics. Under optimal ionic conditions, but in the absence of NH(4)(+), ouabain (K(I)=117.3+/-3.5 mumol L(-1)) and orthovanadate inhibited up to 67% of the ATPase activity. The inhibition studies performed suggest the presence of F(0)F(1), V- and P-ATPases, but not Na(+)-, K(+)- or Ca(2+)-ATPases as contaminants in the gill microsomal preparation. (Na(+), K(+))-ATPase activity was synergistically modulated by NH(4)(+) and K(+). At 20 mmol L(-1) K(+), a maximum rate of V=290.8+/-14.5 U mg(-1) was seen as NH(4)(+) concentration was increased up to 50 mmol L(-1). However, at fixed NH(4)(+) concentrations, no additional stimulation was found for increasing K(+) concentrations (V=135.2+/-4.1 U mg(-1) and V=236.6+/-9.5 U mg(-1) and for 10 and 30 mmol L(-1) NH(4)(+), respectively). This is the first report to detail ionic modulation of gill (Na(+), K(+))-ATPase in C. vittatus, revealing an asymmetrical, synergistic stimulation of the enzyme by K(+) and NH(4)(+), as yet undescribed for other (Na

  20. Is the Bangweulu Basin in Zambia the Eroded Remnant of a Large, Multiring Impact Crater?

    NASA Astrophysics Data System (ADS)

    Master, S.

    1993-07-01

    The Bangweulu Basin (BB) (ca. 29 degrees-31 degrees E, 10 degrees-12 degrees S) is a roughly circular depression, ~150 km in diameter, on the Bangweulu Block of Zambia. The basin, about 1148 m ASL, is occupied by Lakes Bangweulu (~85 km long) and Kampolombo (~20 km long) and the Bangweulu Swamps [1,2]. The basement consists partly of granitoids (~1.8 Ga) together with ~1.1-Ga Katangan cover rocks. To the north, cover rocks of the Mporokoso Group (~1.8-1.3 Ga) form the arcuate Luongo Fold Belt [3], partly defining the perimeter of the outermost ring (R = 125 km) of the Bangweulu structure. Drainage into the BB is centripetal, with one outlet in the south, draining into a tributary of the Luapula River, which then curves in a broad arc toward the north, along the Zambia-Zaire border, before entering Lake Mweru. Rivers entering the BB include the Luansenshi, which rises in the north and flows in an arc to the southeast and south before joining the Chambeshi River, which flows southwest, west, and northwest before entering Lake Bangweulu. There is an arcuate watershed in the west (at R = 100 km), to the west of which rivers drain to the southwest and west into the Luapula River. Several elongate curved sliver-like islands, including Mbawala (~30 x 4 km) and Chisi, are present in Lake Bangweulu. The curvature of the islands follows the arcuate northwest boundary of the lake in a concentric manner. Unlike all the other major lakes in Zambia and surrounding areas (Mweru, Tanganyika, Rukwa, Malawi, and Kariba), which occupy seismically active rift structures [4,5], the Bangweulu Basin is generally aseismic, and is unrelated to rifting. There is a positive aeromagnetic intensity anomaly over the central Bangweulu depression, and there is also a magnetic anomaly density high over the central part of the BB, surrounded by a concentric low [6]. A roughly circular anomaly, outlined by the -140 mgal contour, of the regional Bouguer gravity field is centerd on Lake Bangweulu

  1. Claudins in a primary cultured puffer fish (Tetraodon nigroviridis) gill epithelium model alter in response to acute seawater exposure.

    PubMed

    Bui, Phuong; Kelly, Scott P

    2015-11-01

    Gill epithelium permeability and qualitative/quantitative aspects of gill claudin (cldn) tight junction (TJ) protein transcriptomics were examined with a primary cultured model gill epithelium developed using euryhaline puffer fish (Tetraodon nigroviridis) gills. The model was prepared using seawater-acclimated fish gills and was cultured on permeable cell culture filter supports. The model is composed of 1-2 confluent layers of gill pavement cells (PVCs), with the outer layer exhibiting prominent apical surface microridges and TJs between adjacent cells. During development of electrophysiological characteristics, the model exhibits a sigmoidal increase in transpithelial resistance (TER) and plateaus around 30 kΩcm(2). At this point paracellular movement of [(3)H]polyethylene glycol (PEG) 4000 was low at ~1.75 cm s(-1)×10(-7). When exposed to apical seawater (SW) epithelia exhibit a marked decrease in TER while PEG flux remained unchanged for at least 6 h. In association with this, transcript encoding cldn TJ proteins cldn3c, -23b, -27a, -27c, -32a and -33b increased during the first 6 h while cldn11a decreased. This suggests that these proteins are involved in maintaining barrier properties between gill PVCs of SW fishes. Gill cldn mRNA abundance also altered 6 and 12 h following abrupt SW exposure of puffer fish, but in a manner that differed qualitatively and quantitatively from the cultured model. This most likely reflects the cellular heterogeneity of whole tissue and/or the contribution of the endocrine system in intact fish. The current study provides insight into the physiological and transcriptomic response of euryhaline fish gill cells to a hyperosmotic environment. PMID:26239219

  2. Oxygen utilization and the branchial pressure gradient during ram ventilation of the shortfin mako, Isurus oxyrinchus: is lamnid shark-tuna convergence constrained by elasmobranch gill morphology?

    PubMed

    Wegner, Nicholas C; Lai, N Chin; Bull, Kristina B; Graham, Jeffrey B

    2012-01-01

    Ram ventilation and gill function in a lamnid shark, the shortfin mako, Isurus oxyrinchus, were studied to assess how gill structure may affect the lamnid-tuna convergence for high-performance swimming. Despite differences in mako and tuna gill morphology, mouth gape and basal swimming speeds, measurements of mako O(2) utilization at the gills (53.4±4.2%) and the pressure gradient driving branchial flow (96.8±26.1 Pa at a mean swimming speed of 38.8±5.8 cm s(-1)) are similar to values reported for tunas. Also comparable to tunas are estimates of the velocity (0.22±0.03 cm s(-1)) and residence time (0.79±0.14 s) of water though the interlamellar channels of the mako gill. However, mako and tuna gills differ in the sites of primary branchial resistance. In the mako, approximately 80% of the total branchial resistance resides in the septal channels, structures inherent to the elasmobranch gill that are not present in tunas. The added resistance at this location is compensated by a correspondingly lower resistance at the gill lamellae accomplished through wider interlamellar channels. Although greater interlamellar spacing minimizes branchial resistance, it also limits lamellar number and results in a lower total gill surface area for the mako relative to tunas. The morphology of the elasmobranch gill thus appears to constrain gill area and, consequently, limit mako aerobic performance to less than that of tunas. PMID:22162850

  3. Mass-height profile and total mass transport of wind eroded aeolian sediments from rangelands of the Indian Thar Desert

    NASA Astrophysics Data System (ADS)

    Mertia, R. S.; Santra, Priyabrata; Kandpal, B. K.; Prasad, R.

    2010-11-01

    Wind erosion is an active land degradation process in the Indian Thar Desert and severe dust storm events during hot summer months in the region are very common. Assessment of soil loss due to dust storm events from major land use systems of the Indian Thar Desert is highly essential for proper environmental planning. Characterization of the mass-height profile of wind eroded aeolian sediment is an important step to compute soil loss/mass transport but was not previously studied in the region. In the present study, aeolian mass fluxes (kg m -2) at different heights from soil surface were measured at two major rangelands in the Indian Thar Desert: Overgrazing rangeland at Jaisalmer (26°55'N and 70°57'E), and controlled grazing rangeland at Chandan (27°01'N and 71°01'E). Evaluation of several mass-height profile models revealed that a power decay function [ q( z) = az-b, where q( z) is the measured mass flux at an height of z (m) from soil surface; a and b are parameters of the equation] was best to characterize the mass-height relationship of aeolian sediments from the Indian Thar Desert. The average mass transport rate (kg m -1 day -1) or the total soil loss during hot summer months was significantly higher at the overgrazed rangeland site than at the controlled grazing rangeland site. Therefore, protection of existing rangelands, which comprise about 80% geographical area of the Indian Thar Desert may check the land degradation process due to wind erosion.

  4. Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth bass (Micropterus salmoides)

    USGS Publications Warehouse

    Walsh, Heather L.; Iwanowicz, Luke R.; Glenney, Gavin W.; Iwanowicz, Deborah D.; Blazer, Vicki

    2012-01-01

    Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii n. sp. was found in largemouth and smallmouth bass. Small, spherical, white plasmodia of M. branchiarum from smallmouth bass were observed grossly in the gills; these plasmodia had an average length of 320.3 µm and width of 246.1 µm. The development of the plasmodia is intralamellar in the secondary lamellae of the gills. Mature spores were pyriform in shape with a length of 12.8 ± 1.4 (8.1–15.1) µm and width of 6.9 ± 1.1 (4.0–9.0) µm. Analysis of SSU rDNA identified M. branchiarum in a sister-group to 3 species of Henneguya, although morphologically caudal appendages were absent. Myxobolus micropterii observed in the gills of largemouth and smallmouth bass had larger, ovoid, cream-colored plasmodia with an average length of 568.1 µm and width of 148.1 µm. The cysts developed at the distal end of the gill filament within the primary lamellae. The mature spores were ovoid in shape with a length of 10.8 ± 0.7 (9.2–12.2) µm and width of 10.6 ± 0.6 (9.0–11.8) µm. SSU rDNA analysis placed M. micropterii in a sister group with Henneguya lobosa and Myxobolus oliveirai. The highest prevalence of M. branchiarum was observed in the gills of bass collected from the Cowpasture River (50.9%). Prevalence was 44.6% in bass from the Potomac River and only 4.3% in bass collected from the Shenandoah River. A seasonal study of M. branchiarum, which included both infected and uninfected smallmouth bass, determined that a significantly higher intensity was observed in the spring than in the summer (P < 0.001) or fall (P  =  0.004). In an analysis excluding uninfected

  5. Description of two new gill myxozoans from smallmouth (Micropterus dolomieu) and largemouth (Micropterus salmoides) bass.

    PubMed

    Walsh, Heather L; Iwanowicz, Luke R; Glenney, Gavin W; Iwanowicz, Deborah D; Blazer, Vicki S

    2012-04-01

    Two previously undescribed species of myxozoan parasites were observed in the gills of bass inhabiting the Potomac and James River basins. They are described using morphological characteristics and small-subunit (SSU) rDNA gene sequences. Both were taxonomically identified as new species of Myxobolus; Myxobolus branchiarum n. sp. was found exclusively in smallmouth bass, and Myxobolus micropterii n. sp. was found in largemouth and smallmouth bass. Small, spherical, white plasmodia of M. branchiarum from smallmouth bass were observed grossly in the gills; these plasmodia had an average length of 320.3 µm and width of 246.1 µm. The development of the plasmodia is intralamellar in the secondary lamellae of the gills. Mature spores were pyriform in shape with a length of 12.8 ± 1.4 (8.1-15.1) µm and width of 6.9 ± 1.1 (4.0-9.0) µm. Analysis of SSU rDNA identified M. branchiarum in a sister-group to 3 species of Henneguya , although morphologically caudal appendages were absent. Myxobolus micropterii observed in the gills of largemouth and smallmouth bass had larger, ovoid, cream-colored plasmodia with an average length of 568.1 µm and width of 148.1 µm. The cysts developed at the distal end of the gill filament within the primary lamellae. The mature spores were ovoid in shape with a length of 10.8 ± 0.7 (9.2-12.2) µm and width of 10.6 ± 0.6 (9.0-11.8) µm. SSU rDNA analysis placed M. micropterii in a sister group with Henneguya lobosa and Myxobolus oliveirai . The highest prevalence of M. branchiarum was observed in the gills of bass collected from the Cowpasture River (50.9%). Prevalence was 44.6% in bass from the Potomac River and only 4.3% in bass collected from the Shenandoah River. A seasonal study of M. branchiarum , which included both infected and uninfected smallmouth bass, determined that a significantly higher intensity was observed in the spring than in the summer (P < 0.001) or fall (P  =  0.004). In an analysis excluding uninfected bass, a

  6. Interrill Erodibility of P and C on conventially and organically farmed Devon soils

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.

    2012-04-01

    Soil erosion can have significant off-site effects on water quality and thus human and habitat health. Apart from sedimentation, the transfer of nutrients, both dissolved and particulate, is a major concern. The particulate transfer of nutrients from agricultural land can occur either by rill or interrill erosion. Rill erosion is non-selective and affects only a limited extent of agricultural land. Interrill processes such as crusting, splash and raindrop-impacted wash, on the other hand, act on all cropland and affect the quality of the water from all areas generating runoff. A significant amount of phosphorus (P) is contained in the surface soil layer transformed by interrill processes annually. In the EU, the P content of a crusted (2 mm) surface layer corresponds to 4 to 40 kg ha-1 of P on arable land (1.094 mil km2). Therefore, the role of interrill processes and erosion for regional nutrient cycling requires close attention. Interrill erosion is a complex phenomenon, involving the detachment, transport and deposition of soil particles by raindrop impacted flow. Resistance to interrill erosion varies between soils depending on their physical, chemical and mineralogical properties. In addition, significant changes in soil resistance to interrill erosion occur during storms as a result of changes in surface roughness, cohesion and particle size. As a consequence, erosion on interrill areas is selective, moving the most easily detached small and/or light soil particles which are often enriched in clay, P and organic C. Commonly, the risk of erosion associated with organically farmed soils is lower than those farmed in a conventional way. This is attributed to greater aggregate stability and thus greater infiltration and lower erodibility. Erosion of nutrients on organically farmed soils is therefore considered to be reduced by the same order of magnitude than the amount of eroded soil compared to conventionally farmed soils. However, the selective nature of

  7. Asteroid surface archaeology: Identification of eroded impact structures by spectral properties on (4) Vesta

    NASA Astrophysics Data System (ADS)

    Hoffmann, M.; Nathues, A.; Schäfer, M.; Schmedemann, N.; Vincent, J.; Russell, C.

    2014-07-01

    Introduction: Vesta's surface material is characterized as a deep regolith [1,2], mobilized by countless impacts. The almost catastrophic impact near Vesta's south pole, which has created the Rheasilvia basin, and the partly overlapping older impact of similar size, Veneneia, have not only reshaped the areas of their interior (roughly 50 % of the Vesta surface), but also emplaced each time a huge ejecta blanket of similar size, thus covering the whole remaining surface. In this context, pristine and even younger morphologic features have been erased. However, the spectral signatures of the early differentiation and alteration products by impacts have partially remained in situ. While near the north pole several large old eroded impact features are visible, the equatorial zone close to the basin rims seems to be void of those. Since it is unlikely, that this zone has been entirely avoided by large projectiles, in this area the results of such impacts may have left morphologically not detectable remnants: Individual distribution of particle sizes and altered photometric properties, excavated layers, shock metamorphism, melt generation inside particles and on macroscopic scales, and emplacement of exogenous projectile material. An analysis by color ratio images and spatial profiles of diagnostic spectral parameters reveals such features. Results: Based on local spectroscopic evidence we have detected eroded impact features of three categories: 1) Small craters with diameters of a few kilometers, 2) Large craters or, if even larger, incipient impact basins, 3) Sub-global ejecta blankets. The eastern part of Feralia Planitia, diameter 140 km, has little evidence of a round outline in the shape model, but it features spectral gradients towards its center. A feature of similar size, centered north of Lucaria Tholus becomes only visible by a similar spectra gradient and a circular outline in specific spectral ratio mosaics. These features seem to be related to the

  8. Comparison of soil erodibility factors in USLE, RUSLE2, EPIC and Dg models based on a Chinese soil erodibiity database.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erodibility (K-value) is a key parameter in erosion prediction and is important for conservation planning in the face of a rising need for protecting the limited land resources. This study investigated the predictive capability of the K-value estimated by Universal Soil Loss Equation (USLE), Re...

  9. Mineral-organic matter associations in eroding hillslopes: findings from headwater catchments in the Southern Sierra Nevada (Invited)

    NASA Astrophysics Data System (ADS)

    Berhe, A.; Stacy, E.; McCorkle, E. P.; Johnson, D. W.; Hunsaker, C. T.; Hart, S. C.

    2013-12-01

    Mineral-organic matter (OM) associations--physical encapsulation of OM inside soil aggregates and chemical bonding and complexation of organic functional groups with soil minerals--determine the proportion of soil organic matter (SOM) that is redistributed and mineralized during and after erosional transport of sediments downhill, as well as the stability of the eroded SOM post-deposition. The susceptibility of SOM to decomposition and its stabilization mechanisms can change during and after erosion as a result of: aggregate breakdown or detachment due to kinetic energy of raindrops and/or shearing during lateral transport, and reconfiguration of mineral-OM associations through formation of new and strengthening of existing mineral-OM associations in depositional environments that are enriched in carbon (C) and reactive soil minerals. The goal of this study was to determine how concentration, nature and distribution of SOM in soil fractions vary between eroding slopes and sediments exported from eroding catchments. Free organic particles exported from eroding watersheds typically represent <30% of total carbon mobilized by erosion, compared to <20% mobilized as aggregate protected C and <30% as C complexed with Fe and Al oxides. Our results show that there is large variability in nature of exported material across eight headwater catchments that is not directly related to watershed size or climatic variability. In addition, we quantified the rate at which different OM fractions are preferentially transported and can be potentially lost through decomposition during lateral transport.

  10. Measuring the erodibility of cohesive soils influenced by seepage forces using a laboratory jet erosion test device

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seepage influences the erodibility of streambanks, streambeds, dams, and embankments. However, the interaction between fluvial and seepage mechanisms in cohesive soils is still poorly understood. Usually the erosion rate of cohesive soils due to fluvial forces is computed using an excess shear str...

  11. Estimating concentrated flow erodibility parameters from pre- and post-fire rangeland field data for physically-based erosion modeling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In physically based soil erosion models a concentrated flow erodibility parameter is necessary to run the model. This parameter is usually set to a relatively insignificant value when applying models on rangeland ecosystems as soil erosion induced by concentrated flow on these ecosystems tends to be...

  12. Metolachlor dissipation following fall and spring application to eroded and rehabilitated landscapes of the US Corn Belt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the effects of landscape position and soil properties on the rate of metolachlor dissipation and weed control efficacy of fall- and spring-applied metolachlor in eroded and rehabilitated landforms in the midwestern United States. Soil-landscape rehabilitation result...

  13. 7 CFR Exhibit M to Subpart G of... - Implementation Procedures for the Conservation of Wetlands and Highly Erodible Land Affecting...

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Security Act of 1985, Pub. L. 99-198. The purposes of these Subtitles are to: Reduce soil loss due to wind... Program loans” means Farm Operating Loans, Farm Ownership Loans, Emergency Loans, and Soil and Water Loans... erodible land is predominant, as determined by the Soil Conservation Service (SCS), is or would be used...

  14. 7 CFR Exhibit M to Subpart G of... - Implementation Procedures for the Conservation of Wetlands and Highly Erodible Land Affecting...

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Security Act of 1985, Pub. L. 99-198. The purposes of these Subtitles are to: Reduce soil loss due to wind... Program loans” means Farm Operating Loans, Farm Ownership Loans, Emergency Loans, and Soil and Water Loans... erodible land is predominant, as determined by the Soil Conservation Service (SCS), is or would be used...

  15. 7 CFR Exhibit M to Subpart G of... - Implementation Procedures for the Conservation of Wetlands and Highly Erodible Land Affecting...

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Security Act of 1985, Pub. L. 99-198. The purposes of these Subtitles are to: Reduce soil loss due to wind... Program loans” means Farm Operating Loans, Farm Ownership Loans, Emergency Loans, and Soil and Water Loans... erodible land is predominant, as determined by the Soil Conservation Service (SCS), is or would be used...

  16. 7 CFR Exhibit M to Subpart G of... - Implementation Procedures for the Conservation of Wetlands and Highly Erodible Land Affecting...

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Security Act of 1985, Pub. L. 99-198. The purposes of these Subtitles are to: Reduce soil loss due to wind... Program loans” means Farm Operating Loans, Farm Ownership Loans, Emergency Loans, and Soil and Water Loans... erodible land is predominant, as determined by the Soil Conservation Service (SCS), is or would be used...

  17. 7 CFR Exhibit M to Subpart G of... - Implementation Procedures for the Conservation of Wetlands and Highly Erodible Land Affecting...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Security Act of 1985, Pub. L. 99-198. The purposes of these Subtitles are to: Reduce soil loss due to wind... Program loans” means Farm Operating Loans, Farm Ownership Loans, Emergency Loans, and Soil and Water Loans... erodible land is predominant, as determined by the Soil Conservation Service (SCS), is or would be used...

  18. Fine gravel controls hydrologic and erodibility responses to trampling disturbance for coarse-textured soils with weak cyanobacterial crusts.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We compared short-term effects of lug-soled boot trampling disturbance on water infiltration and soil erodibility on coarse-textured soils covered by a mixture of fine gravel and coarse sand over weak cyanobacterially-dominated biological soil crusts. Trampling significantly reduced final infiltrati...

  19. Low sorption and fast dissipation of the herbicide saflufenacil in surface soils and subsoils of an eroded prairie landscape

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Saflufenacil partitioning and dissipation was evaluated in soils from an eroded prairie landscape to provide information on its expected environmental fate. Saflufenacil Kd values followed trends in soil organic carbon content. In surface soils, Kd values ranged from 0.05 to 0.2 L kg-1 in the deposi...

  20. Physical Model and numerical modeling of earth-surface flows on erodible beds

    NASA Astrophysics Data System (ADS)

    Ouyang, Chaojun; He, Siming; Zhou, Gordan

    2015-04-01

    The bed sediment erosion and depositional processes along the channel play a significant role in geo-hazards like debris flows, landslides and dam failures. Large quantities of theoretical, experimental and field researches have shown that the final debris flow volume could possibly be several-fold beyond its initial volume as it incorporates material from the basal beds. A number of catastrophic events imply the damage is still generally underestimated, especially in the area influenced by strong earthquake such as Wenchuan 5.12 earthquake in 2008. An increasing number of researchers have been dedicated to using depth-integrated Na-vier-Stokes equations to determine the runout distance and final deposition volume of land-slides or debris flows over erodible beds. Nevertheless, it has been found out that the role of mass and momentum exchange at flow-bed boundaries in conservation equations was im-properly exhibited in some literatures, as reviewed by Iverson and Ouyang (2014). In addition, it is also illustrated that erosion or deposition rates at the interface between layers must satisfy three jump conditions which are similar to Rankine-Hugoniot conditions in gas dynamics. Here, several basal entrainment models satisfying the momentum jump conditions are proposed. Coupled mass and momentum equations integrated with sediment transport and morphological evolution are presented. A time and space second-order MacCormack-TVD finite difference method, which does not require the knowledge of the characteristic speeds of the system, is programmed to solve the coupled equations. A series of numerical simulations compared with theoretical solution and laboratory experiments were carried out to verify the accuracy and its robustness. Numerical comparisons with USGS flume experiment and Hongchun gully debris flow in Wenchuan earthquake-induced area are well carried out. It is exhibited the momentum exchange term between the flows and the basal materials has a sig

  1. Erosion characteristics of an erodible tablet incorporated in a time-delayed capsule device.

    PubMed

    McConville, Jason T; Ross, Alistair C; Florence, Alastair J; Stevens, Howard N E

    2005-01-01

    A time-delayed oral drug delivery device was investigated in which an erodible tablet (ET), sealing the mouth of an insoluble capsule, controlled the lag-time prior to drug release. The time-delayed capsule (TDC) lag-time may be altered by manipulation of the excipients used in the preparation of the ET. Erosion rates and drug release profiles from TDCs were investigated with four different excipient admixtures with lactose: calcium sulphate dihydrate (CSD), dicalcium phosphate (DCP), hydroxypropylmethyl cellulose (HPMC; Methocel K100LV grade) and silicified microcrystalline cellulose (SMCC; Prosolv 90 grade). Additionally, the compressibility of different insoluble coated capsules was tested at different moisture levels to determine their overall integrity and suitability for oral delivery. Erosion rates of CSD, DCP, and SMCC displayed a nonlinear relationship to their concentration, while HPMC indicated rapid first-order erosion followed by zero-order erosion, the onset of which was dependent on the HPMC concentration. Capsule integrity was confirmed to be most suitable for oral delivery when the insoluble ethyl cellulose coat was applied to a hard gelatin capsule using an organic spray coating process. T50% drug release times varied between 245 (+/-33.4) and 393 (+/-40.8) minutes for 8% and 20% DCP, respectively, T50% release times of 91 (+/-22.1) and 167 (+/-34.6) were observed for 8% and 20% CSD; both formulations showed incidence of premature drug release. The SMCC formulations showed high variability due to lamination effects. The HPMC formulations had T50% release times of 69 (+/-13.9), 213 (+/-25.4), and 325 (+/-30.3) minutes for 15%, 24%, and 30% HPMC concentrations respectively, with no premature drug release. In conclusion, HPMC showed the highest reproducibility for a range of time-delayed drug release from the assembled capsule formulation. The method of capsule coating was confirmed to be important by investigation of the overall capsule integrity at

  2. Effects of non-erodible particles on aeolian erosion: Wind-tunnel simulations of a sand oblong storage pile

    NASA Astrophysics Data System (ADS)

    Furieri, B.; Russeil, S.; Santos, J. M.; Harion, J. L.

    2013-11-01

    Non-erodible particles have strong influence on the aeolian erosion phenomena. An oblong stockpile model of sand (bimodal granulometry) was implemented to perform wind-tunnel experiments as similar literature works have only carried out experimental investigations on a flat bed of particles. Thus, the influence of the fluid flow structures around the complex obstacle will be analysed. The tested configurations consisted of two different values of non-erodible particles cover rate (10% and 20%), and three free stream velocities (6, 7 and 8 m s-1). Good repeatability was found. The results showed that the largest amount of particles emitted was for the highest wind velocity and the smallest cover rate. The temporal decreasing of emitted mass flux was found steeper for larger amount of non-erodible particles and higher velocity. The mass flux of particles decreases very strongly in the first four minutes of measurements and the cover rate influences this downward sloping. The same analysis applies for the effects of the free stream velocity. The qualitative analysis (high quality photographic system) of the stockpile surface gradual change has shown that non-erodible particles aggregation induces a pavement effect on some areas of the pile. This analysis indicated typical wind erosion zones: high wall friction on the crest line and lateral sides; low wall friction on the windward wall near the ground and on the recirculation downstream the leeward wall. The results and discussions presented here allows for the understanding of the impact of non-erodible particle on dust emissions.

  3. In vitro assay for the toxicity of silver nanoparticles using heart and gill cell lines of Catla catla and gill cell line of Labeo rohita.

    PubMed

    Taju, G; Abdul Majeed, S; Nambi, K S N; Sahul Hameed, A S

    2014-04-01

    Silver nanoparticles (Ag-NPs) are used in commercial products for their antimicrobial properties. The Ag-NPs in some of these products are likely to reach the aquatic environment, thereby posing a health concern for humans and aquatic species. The silver nanoparticles were synthesized and characterized using, UV-vis spectra, Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) analysis. Acute toxicity tests on fish were conducted by exposing Catla catla and Labeo rohita for 96h to AgNO3 and Ag-NPs under static conditions. The cytotoxic effect of AgNO3 and Ag-NPs in Sahul India C. catla heart cell line (SICH), Indian C. catla gill cell line (ICG) and L. rohita gill cell line (LRG) was assessed using MTT and neutral red (NR) assay. Linear correlations between each in vitro EC50 and the in vivo LC50 data were highly significant. DNA damage and nuclear fragmentation (condensation) were assessed by comet assay and Hoechst staining, respectively in SICH, ICG and LRG cells exposed to Ag-NPs. The results of antioxidant parameter obtained show significantly increased lipid peroxidation (LPO) level and decreased level of GSH, SOD and CAT in SICH, ICG and LRG cell lines after exposure to increasing Ag-NPs in a concentration-dependent manner. This work proves that fish cell lines could be used as an alternative to whole animals using cytotoxicity tests, genotoxicity tests and oxidative stress assessment after exposure to nanoparticles. PMID:24524868

  4. A case of complete loss of gill parasites in the invasive cichlid Oreochromis mossambicus.

    PubMed

    Firmat, Cyril; Alibert, Paul; Mutin, Guillaume; Losseau, Michèle; Pariselle, Antoine; Sasal, Pierre

    2016-09-01

    This study investigates the recent evolution of a rich parasite community associated with one of the world's most invasive species, the cichlid fish Oreochromis mossambicus. Populations from the species' native range (Mozambique) are compared to a population from New Caledonia (Wester Pacific), an island where the species was introduced in 1954. The results support the complete local extinction of the gill parasite community in the course of the invasion process. Up to six gill parasite species per locality were documented in the O. mossambicus native range, and previous surveys consistently reported at least one parasite species introduced along African cichlid species established out of Africa. The absence of parasites in New Caledonia is therefore exceptional. This can be attributed to local factors, such as a strong initial population bottleneck, the likely absence of multiple host introductions, and the frequent occurrence of brackish watersheds that might enhance the probability for natural deparasitation. PMID:27334451

  5. Comparative analysis of gill transcriptomes of two freshwater crayfish, Cherax cainii and C. destructor.

    PubMed

    Ali, Muhammad Yousuf; Pavasovic, Ana; Amin, Shorash; Mather, Peter B; Prentis, Peter J

    2015-08-01

    We undertook deep sequencing of gill transcriptomes from two freshwater crayfish, Cherax cainii and Cherax destructor, in order to generate genomic resources for future genomics research. Over 83 and 100 million high quality (quality score (Q)≥30) paired-end Illumina reads (150 bp) were assembled into 147,101 and 136,622 contigs in C. cainii and C. destructor, respectively. A total of 24,630 and 23,623 contigs received significant BLASTx hits and allowed the identification of multiple gill expressed candidate genes associated with pH and salinity balance. These functionally annotated transcripts will provide a resource to facilitate comparative genomic research in the genus Cherax, and in particular allow insights into respiratory and osmoregulatory physiology of this group of animals. PMID:25797793

  6. Effects of bacteria on the growth of an amoeba infecting the gills of turbot.

    PubMed

    Paniagua, E; Paramá, A; Iglesias, R; Sanmartín, M L; Leiro, J

    2001-05-01

    We analysed the influence of various bacteria on the in vitro growth of trophozoites of a Platyamoeba strain isolated from diseased gill tissues of cultured turbot. Little or no growth was shown by amoebae cultured in the presence of (1) the turbot-pathogenic bacteria Vibrio anguillarum, Aeromonas salmonicida or Streptococcus sp., (2) Pasteurella piscicida or Vibrio vulnificus (pathogenic for some fishes but not turbot), or (3) the non-pathogenic 'environmental' bacteria Vibrio campbelli, Vibrio fluvialis or Pseudomonas dondorofii. The only bacteria which were successfully utilized as food sources were Aeromonas hydrophila (pathogenic for some fishes but not turbot) and the non-pathogens Vibrio natriegens, Pseudomonas nautica and Escherichia coli. These results suggest that the colonization of the gills of cultured turbot by the epizoic amoeba Platyamoeba may be an indicator of faecal contamination. PMID:11411647

  7. Long-term Follow-up of a Case of Gilles de la Tourette's syndrome

    PubMed Central

    Das, Soumitra; Kartha, Arjun; Purushothaman, Sumesh Thoppil

    2016-01-01

    Gilles de la Tourette's syndrome is a combined vocal and multiple motor tic disorder. Here, we present a case of Tourette's syndrome who attended our psychiatric causality with severe depression and suicidal ideation. On reviewing follow-up records of 23 years, we come to know about the academic decline and nicotine dependence in the early childhood. He also developed co-morbid obsessive compulsive disorder (OCD) along with severe depression. He was agitated and self-injurious. We diagnosed him as Gilles de la Tourette's syndrome with co-morbid OCD, depression, nicotine dependence. The patient was treated with haloperidol, sertraline, and clonidine when he developed mixed switch that necessitated us to stop sertraline. Hence, he was treated with a mood stabilizer and he remitted. Here, we want to show how Tourette's syndrome can take a longer course with different co-morbidities in a single person's life. As per our knowledge, such presentation is relatively rare in Indian literature. PMID:27335527

  8. Absence of histophatological response to cadmium in gill and digestive diverticula of the mussel, Mytilus edulis

    SciTech Connect

    Giraud, A.S.; Webster, L.K.; Fabris, J.G.; Collett, L.C.; Yeomans, N.D.

    1986-01-01

    The blue mussel (Mytilus edulis) has been proposed for use as a sentinel organism to monitor the effects of marine pollution (Goldberg et al., 1978). Recently, there has been interest in quantifying histopathological changes in mussel tissues, as one indicator of pollution-induced stress. Cadmium is a common and toxic aquatic pollutant. Gill and digestive diverticula have been shown to be major sites of cadmium detoxification. In these same tissues, histopathological changes have been demonstrated after exposure to crude oil and to an oil dispersant. However, whether similar morphological changes are induced by heavy metals, such as cadmium, is not known. In this study, the authors have assessed the cellular effects of sublethal concentrations of cadmium on the gill and digestive diverticula of Mytilus.

  9. Long-term Follow-up of a Case of Gilles de la Tourette's syndrome.

    PubMed

    Das, Soumitra; Kartha, Arjun; Purushothaman, Sumesh Thoppil

    2016-01-01

    Gilles de la Tourette's syndrome is a combined vocal and multiple motor tic disorder. Here, we present a case of Tourette's syndrome who attended our psychiatric causality with severe depression and suicidal ideation. On reviewing follow-up records of 23 years, we come to know about the academic decline and nicotine dependence in the early childhood. He also developed co-morbid obsessive compulsive disorder (OCD) along with severe depression. He was agitated and self-injurious. We diagnosed him as Gilles de la Tourette's syndrome with co-morbid OCD, depression, nicotine dependence. The patient was treated with haloperidol, sertraline, and clonidine when he developed mixed switch that necessitated us to stop sertraline. Hence, he was treated with a mood stabilizer and he remitted. Here, we want to show how Tourette's syndrome can take a longer course with different co-morbidities in a single person's life. As per our knowledge, such presentation is relatively rare in Indian literature. PMID:27335527

  10. Experimental lead nitrate poisoning: microscopic and ultrastructural study of the gills of tench (Tinca tinca, L.).

    PubMed Central

    Roncero, V; Vincente, J A; Redondo, E; Gãzquez, A; Duran, E

    1990-01-01

    A microscopic, ultrastructural, and morphometric study was made of the gills of tench (Tinca tinca, L.) subjected to acute experimental lead nitrate poisoning. Twenty-one adult tench were subjected to poisoning and a further 22 were used as controls. Lesions were characterized by the appearance of edema and epithelial hyperplasia and necrosis, both in cells forming part of the filtration barrier and in those in the interlamellar space. These processes developed in the course of the experiment, leading to the death of tench after 12 to 15 days of exposure to 75 ppm lead nitrate, at which point the concentrations of lead in the gills had reached their maximum. Images FIGURE 1. FIGURE 2. FIGURE 5. FIGURE 6. FIGURE 7. FIGURE 8. FIGURE 9. FIGURE 10. FIGURE 11. FIGURE 12. FIGURE 13. FIGURE 14. FIGURE 15. FIGURE 16. FIGURE 17. FIGURE 18. FIGURE 19. PMID:2088740

  11. Recurrent amoebic gill infestation in rainbow trout cultured in a semiclosed water recirculation system

    USGS Publications Warehouse

    Noble, A.C.; Herman, R.L.; Noga, E.J.; Bullock, G.L.

    1997-01-01

    Five lots of commercially purchased juvenile rainbow trout Oncorhynchus mykiss (17-44 g) stocked in a continuous-production water recirculation system became infested with gilt amoebae. The amoebae were introduced into the recirculation system, as evidenced by their presence on gills of fish held in quarantine tanks. Based on their morphology, as seen in histological sections and by electron microscopy, the amoebae appeared to be more closely related to the family Cochliopodiidae than to other taxa of free living amoebae. Attempts to culture the amoebae in different media, at different temperatures of incubation, and in fish cell culture were not successful. Initial treatment of the recirculation system with formalin at 167 parts per million (ppm) for 1 h eliminated amoebae from the gills. Subsequent treatments of the entire system with formalin at 50-167 ppm reduced the intensity of further infestations.

  12. Testate amoeba Rhogostoma minus Belar, 1921, associated with nodular gill disease of rainbow trout, Oncorhynchus mykiss (Walbaum).

    PubMed

    Dyková, I; Tyml, T

    2016-05-01

    The case study targeted to determine the aetiology of nodular gill disease (NGD) of farmed rainbow trout. The methods included microscopical examination of gill material in fresh, culturing of isolated organisms, histology, transmission electron microscopy and molecular biology identification. The results revealed an intravital colonization of fish gills by the testate amoeba Rhogostoma minus Belar, 1921. Rhogostoma infection was found in all fish examined microscopically (15/15); in contrast, naked amoebae related to fully developed NGD lesions were found in minority of these fish (5/15). They belonged to four genera, Acanthamoeba, Vermamoeba, Naegleria and Vannella. Results presented in this study contribute to the mosaic of findings that contrary to amoebic gill disease of marine fish turn attention to the possibility of the heterogeneous, multi-amoeba-species and multifactorial aetiology of NGD. PMID:25952929

  13. Marine sediment and interstitial water: Effects on bioavailability of cadmium to gills of the clam Protothaca staminea

    SciTech Connect

    Hardy, J.T.; Schmidt, R.L.; Apts, C.W.

    1981-12-01

    A study was made to determine first, the kinetics of cadmium sorption on a natural marine sediment and second, the degree to which this sorption as well as interstitial water might effect bioavailability of cadmium to gills of the clam Protothaca staminea. Surface sediment from Sequim Bay, Washington was labelled with Cd 109 and total cadmium concentration determined by radioassay. Gills were added to three types of exposures: 1) control (0.45 um filtered seawater, 2) sediment interstitial water and 3) washed sediment. Prepared samples of gills were counted in a liquid scintillation counter. Results show that addition of a small quantity of washed sediment to the exposure system reduced cadmium accumulation by gills to only 17% of the control. Interstitial water had no significant effect. 1 table, 3 figures (JMT)

  14. Ammonia excretion and expression of transport proteins in the gills and skin of the intertidal fish Lipophrys pholis.

    PubMed

    Souza-Bastos, Luciana R; Páscoa, Maria Inês; Freire, Carolina A; Wilson, Jonathan M

    2014-01-01

    Intertidal pools are intensely challenging environments, due to rapid and extreme fluctuations in water conditions during the tidal cycle. Emersion is another challenge intertidal fishes may face. Mechanisms of ammonia excretion and ion regulation were studied in the resident amphibious blennid Lipophrys pholis. The ammonia transporters Rhcg1 and Rhcg2 were cloned and characterized. Fish were challenged for 24h to 1) emersion, 2) fresh water (FW), and 3) high environmental ammonia (HEA; 1mM NH4Cl), or 4) ammonia loading (1.5μmol/g NH4HCO3). When air exposed, L. pholis maintained aquatic ammonia excretion rates (JAmm) while branchial Na(+)/K(+)-ATPase (NKA) activity increased, but no changes at the protein or mRNA levels of transporters were noted. In FW, JAmm decreased and osmotic problems were encountered. Skin NKA activity decreased, branchial Rhcg2, and skin Rhcg1 and Rhcg2 increased. Exposure to HEA only increased branchial Rhcg2 levels. Although internal ammonia loading only led to a modest non-significant increase in JAmm, skin NKA (activity and α-subunit), carbonic anhydrase protein levels, and branchial Rhcg1 levels increased. In summary, variable responses were observed involving both gill and skin but given the instability of its habitat, the constitutive expression of transporters is likely also of importance. PMID:24055759

  15. Structural and functional changes in gill mitochondrial membranes from the Mediterranean mussel Mytilus galloprovincialis exposed to tri-n-butyltin.

    PubMed

    Fiorini, Rosamaria; Pagliarani, Alessandra; Nesci, Salvatore; Pirini, Maurizio; Tucci, Elisabetta; Ventrella, Vittoria

    2012-04-01

    The use of tributyltin (TBT) as a biocide in antifouling paints leads to a ruinous input of this contaminant in the aquatic environment. Human exposure to TBT mainly occurs through ingestion of contaminated seafood such as filter-feeding mollusks. Tributyltin is known to act as a membrane-active toxicant on several targets, but especially on the mitochondria, and by several mechanisms. The effects of tributyltin on fatty acid composition, on Mg-adenosine triphosphatase (ATPase) activities, and on the membrane physical state were investigated in gill mitochondrial membranes from cultivated mussels Mytilus galloprovincialis exposed to 0.5 µg/L and 1.0 µg/L TBT and unexposed for 120 h. The higher TBT exposure dose induced a decrease in the total and n-3 polyunsaturated fatty acids (PUFAs), especially 22:6 n-3, and an activation of the oligomycin-sensitive Mg-ATPase. Both TBT concentrations decreased mitochondrial membrane polarity detected by Laurdan steady-state fluorescence spectroscopy. These findings may help cast light on the multiple modes of action of this toxicant. PMID:22374617

  16. Evaluating the Hypoxia Response of Ruffe and Flounder Gills by a Combined Proteome and Transcriptome Approach.

    PubMed

    Tiedke, Jessica; Borner, Janus; Beeck, Hendrik; Kwiatkowski, Marcel; Schmidt, Hanno; Thiel, Ralf; Fabrizius, Andrej; Burmester, Thorsten

    2015-01-01

    Hypoxia has gained ecological importance during the last decades, and it is the most dramatically increasing environmental factor in coastal areas and estuaries. The gills of fish are the prime target of hypoxia and other stresses. Here we have studied the impact of the exposure to hypoxia (1.5 mg O2/l for 48 h) on the protein expression of the gills of two estuarine fish species, the ruffe (Gymnocephalus cernua) and the European flounder (Platichthys flesus). First, we obtained the transcriptomes of mixed tissues (gills, heart and brain) from both species by Illumina next-generation sequencing. Then, the gill proteomes were investigated using two-dimensional gel electrophoresis and mass spectrometry. Quantification of the normalized proteome maps resulted in a total of 148 spots in the ruffe, of which 28 (18.8%) were significantly regulated (> 1.5-fold). In the flounder, 121 spots were found, of which 27 (22.3%) proteins were significantly regulated. The transcriptomes were used for the identification of these proteins, which was successful for 15 proteins of the ruffe and 14 of the flounder. The ruffe transcriptome dataset comprised 87,169,850 reads, resulting in an assembly of 72,108 contigs (N50 = 1,828 bp). 20,860 contigs (26.93%) had blastx hits with E < 1e-5 in the human sequences in the RefSeq database, representing 14,771 unique accession numbers. The flounder transcriptome with 78,943,030 reads assembled into 49,241 contigs (N50 = 2,106 bp). 20,127 contigs (40.87%) had a hit with human proteins, corresponding to 14,455 unique accession numbers. The regulation of selected genes was confirmed by quantitative real-time RT-PCR. Most of the regulated proteins that were identified by this approach function in the energy metabolism, while others are involved in the immune response, cell signalling and the cytoskeleton. PMID:26273839

  17. 156 cases of Gilles de la Tourette's syndrome treated by acupuncture.

    PubMed

    Wu, L; Li, H; Kang, L

    1996-09-01

    The principle of clearing Yangming and nourishing the kidney and heart was adopted in the treatment of 156 cases of Gilles de la Tourette's Syndrome with acupuncture. The total effective rate was 92.3%, and the cure rate in children aged 11-15 years was markedly higher than that in children 6-10 years of age. Among 84 cases with abnormal EEG, the pathological waves in 54 disappeared or ameliorated after the treatment. PMID:9389122

  18. Mortality, accumulation, and distribution of zinc in the gill system of the dogfish following zinc treatment

    SciTech Connect

    Crespo, S.; Blasch, J.

    1980-06-01

    Besides being an essential element, Zn has been shown to be toxic to aquatic organisms. Acute lethalities of Zn salts to teleosts have been reported, but few data regarding Zn toxicity to elasmobranchs can be found. To evaluate the effect of Zn on elasmobranchs and to compare the data with those on teleosts this paper studies Zn toxicity and the accumulation of the metal in the gills of the dogfish Scyliorhinus canicula exposed to 180 and 80 ppM of zinc.

  19. The effects of salinity on naphthenic acid toxicity to yellow perch: gill and liver histopathology.

    PubMed

    Nero, V; Farwell, A; Lee, L E J; Van Meer, T; MacKinnon, M D; Dixon, D G

    2006-10-01

    Naphthenic acids (NAs) are naturally occurring saturated linear and cyclic carboxylic acids found in petroleum, including the bitumen contained in the Athabasca Oil Sands deposit in Alberta, Canada. The processing of these oil sands leads to elevated concentrations of NAs, as well as increased salinity from produced waters as a result of ions leaching from the ores, the process aids, and the water associated with the deeper aquifers. These changes can result in waters that challenge reclamation of impacted waters associated with oil sands development. Laboratory tests examined the effects of salinity on NA toxicity using local young-of-the-year yellow perch exposed to a commercially available mixture of NAs (CNA) and an NA mixture that was extracted from oil sands process-affected water (ENA), with and without the addition of sodium sulfate (Na(2)SO(4)). Gill and liver histopathological changes were evaluated in the surviving fish after 3 weeks of exposure. At 6.8 mg/L ENA and 3.6 mg/L CNA, 100% mortality was observed, both with and without the addition of salt. Exposure of yellow perch to 25% of the NA required to give an LC100 (0.9 mg/L CNA; 1. 7 mg/L ENA) resulted in high levels of gill proliferative (epithelial, mucous, and chloride cell) changes, a response that was increased with the addition of 1g/L salt (Na2SO4) for the ENA. The significance of these changes was a reduced gill surface area, which likely caused a reduction in both the transport of NAs within the fish and the exchange of vital respiratory gases. While the gills were affected, no liver alterations were identified following NA or NA+salt exposures. Differences in the chemical composition of the NAs tested may explain the differences in the lethality and histopathology of yellow perch. PMID:16129489

  20. Evaluating the Hypoxia Response of Ruffe and Flounder Gills by a Combined Proteome and Transcriptome Approach

    PubMed Central

    Tiedke, Jessica; Borner, Janus; Beeck, Hendrik; Kwiatkowski, Marcel; Schmidt, Hanno; Thiel, Ralf; Fabrizius, Andrej; Burmester, Thorsten

    2015-01-01

    Hypoxia has gained ecological importance during the last decades, and it is the most dramatically increasing environmental factor in coastal areas and estuaries. The gills of fish are the prime target of hypoxia and other stresses. Here we have studied the impact of the exposure to hypoxia (1.5 mg O2/l for 48 h) on the protein expression of the gills of two estuarine fish species, the ruffe (Gymnocephalus cernua) and the European flounder (Platichthys flesus). First, we obtained the transcriptomes of mixed tissues (gills, heart and brain) from both species by Illumina next-generation sequencing. Then, the gill proteomes were investigated using two-dimensional gel electrophoresis and mass spectrometry. Quantification of the normalized proteome maps resulted in a total of 148 spots in the ruffe, of which 28 (18.8%) were significantly regulated (> 1.5-fold). In the flounder, 121 spots were found, of which 27 (22.3%) proteins were significantly regulated. The transcriptomes were used for the identification of these proteins, which was successful for 15 proteins of the ruffe and 14 of the flounder. The ruffe transcriptome dataset comprised 87,169,850 reads, resulting in an assembly of 72,108 contigs (N50 = 1,828 bp). 20,860 contigs (26.93%) had blastx hits with E < 1e-5 in the human sequences in the RefSeq database, representing 14,771 unique accession numbers. The flounder transcriptome with 78,943,030 reads assembled into 49,241 contigs (N50 = 2,106 bp). 20,127 contigs (40.87%) had a hit with human proteins, corresponding to 14,455 unique accession numbers. The regulation of selected genes was confirmed by quantitative real-time RT-PCR. Most of the regulated proteins that were identified by this approach function in the energy metabolism, while others are involved in the immune response, cell signalling and the cytoskeleton. PMID:26273839