Sample records for deleterious ecological effects

  1. SHORT COMMUNICATION The effect of pathogens on selection against deleterious mutations

    E-print Network

    Agrawal, Aneil F.

    mutations in Drosophila melanogaster. in Drosophila melanogaster JADENE A.YOUNG, CHRISTOPHER P. YOURTH & ANEIL F. AGRAWAL Department of EcologySHORT COMMUNICATION The effect of pathogens on selection against deleterious mutations

  2. Original article The deleterious effects of human erythropoietin

    E-print Network

    Paris-Sud XI, Université de

    contrôle du pro- moteur du gène de la whey acidic protein de lapin chez des lapins transgéniques. Le gèneOriginal article The deleterious effects of human erythropoietin gene driven by the rabbit whey acidic protein gene promoter in transgenic rabbits M Massoud J Attal2 D Thépot H Pointu MG Stinnakre MC

  3. Lidocaine Potentiates the Deleterious Effects of Triamcinolone Acetonide on Tenocytes

    PubMed Central

    Yang, Shu-long; Zhang, Yu-bo; Jiang, Zhi-tao; Li, Zhao-zhu; Jiang, Da-peng

    2014-01-01

    Background Local anesthetics are commonly used for the treatment of a variety of tendinopathies in combination with corticosteroids injection. The goal of this study was to evaluate the effects of lidocaine and triamcinolone acetonide (TA) on cultured rat tenocytes and to determine whether there is a synergistic effect. Material/Methods Rat patellar tendon-derived tenocytes were cultured with or without TA and lidocaine, and the culture without any additive served as the control. Cell morphology and cell viability were evaluated. Expressions of tenocyte-related genes were measured by qRT-PCR. Results TA, when exposed to tenocytes in vitro, significantly decreased cell viability. The cells cultured with TA had a flattened shape. Moreover, the expressions of tenocyte-related genes in tenocytes were markedly decreased in the TA-treated group. We found that 1% lidocaine synergistically increased the deleterious effects of TA. Conclusions Our data provide evidence of the detrimental effects of these drugs on tendon tissues. Injection of TA in combination with 1% lidocaine should be used with caution. PMID:25433272

  4. Relative Effectiveness of Mating Success and Sperm Competition at Eliminating Deleterious Mutations in Drosophila melanogaster

    Microsoft Academic Search

    Sean C. A. Clark; Nathaniel P. Sharp; Locke Rowe; Aneil F. Agrawal

    2012-01-01

    Condition-dependence theory predicts that sexual selection will facilitate adaptation by selecting against deleterious mutations that affect the expression of sexually selected traits indirectly via condition. Recent empirical studies have provided support for this prediction; however, their results do not elucidate the relative effects of pre- and postcopulatory sexual selection on deleterious mutations. We used the Drosophila melanogaster model system to

  5. Effect of drift, selection and recombination on the equilibrium frequency of deleterious mutations.

    PubMed

    John, Sona; Jain, Kavita

    2015-01-21

    We study the stationary state of a population evolving under the action of random genetic drift, selection and recombination in which both deleterious and reverse beneficial mutations can occur. We find that the equilibrium fraction of deleterious mutations decreases as the population size is increased. We calculate exactly the steady state frequency in a nonrecombining population when population size is infinite and for a neutral finite population, and obtain bounds on the fraction of deleterious mutations. We also find that for small and very large populations, the number of deleterious mutations depends weakly on recombination, but for moderately large populations, recombination alleviates the effect of deleterious mutations. An analytical argument shows that recombination decreases disadvantageous mutations appreciably when beneficial mutations are rare as is the case in adapting microbial populations, whereas it has a moderate effect on codon bias where the mutation rates between the preferred and unpreferred codons are comparable. PMID:25451760

  6. TONGUE-PLACED TACTILE BIOFEEDBACK SUPPRESSES THE DELETERIOUS EFFECTS OF MUSCLE FATIGUE ON JOINT POSITION SENSE AT THE ANKLE

    E-print Network

    Paris-Sud XI, Université de

    1 TONGUE-PLACED TACTILE BIOFEEDBACK SUPPRESSES THE DELETERIOUS EFFECTS OF MUSCLE FATIGUE ON JOINT biofeedback. The underlying principle of this biofeedback consisted of supplying individuals experiment was to investigate whether this biofeedback could mitigate the deleterious effect of muscle

  7. Brief report: Labelling effects on the perceived deleterious consequences of pop music listening

    Microsoft Academic Search

    Adrian C. North; David J. Hargreaves

    2005-01-01

    Several correlational studies have supported the claim of conservative protestors that there exists a positive relationship between listening to pop music and adolescent problem behaviours. However, research on the so-called ‘prestige effects’ has shown that experimental participants’ responses to music can be mediated by manipulations of prior information concerning that music. This study investigated whether perceptions of deleterious effects of

  8. Similarity of Deleterious Effects of Divorce on Chinese and American Children.

    ERIC Educational Resources Information Center

    Zhou, Zheng; Bray, Melissa A.; Kehle, Thomas J.; Xin, Tao

    2001-01-01

    Reviews and contrasts the effects of divorce on Chinese children's adjustment to American children of divorce. Results indicate that the deleterious effects of divorce on children's academic and social functioning appear to be similar to that experienced by American children. (Contains 23 references.) (GCP)

  9. Deleterious effects of magnesium intoxication upon the domestic broiler chick

    SciTech Connect

    Lee, S.R.

    1984-01-01

    Dietary levels of 0.6 to 0.8% magnesium in a corn-soy basal were rachitogenic. These rickets appeared most like phosphorus deficiency. Bone Ca/P ratios were numerically quite low implying a lack of transformation from amorphous calcium phosphate to hydroxyapatite. Bone alkaline phosphatase activity was elevated. Additional dietary phosphorus ameliorated, but could not overcome the rachitogenic effects of magnesium. Tibial dyschondroplasia (TD), induced by elevated dietary P, was decreased by high levels of dietary Mg, but with no decrease in plasma phosphorus. Anticoccidial ionophores fed in conjunction with a moderate dietary challenge of Mg (0.48%) produced no clear changes in plasma calcium or Mg, but did interact to reduce body weight. The diarrhea caused by magnesium intoxication is not due to hyperosmotic loads of Mg per se. Rather, Cl was observed to be the major ionic constituent of the gut osmotic load implying different gut ionic fluxes in control versus magnesium intoxicated chicks. These data imply that the cathartic action of Mg is due to hypersecretion of the gut. Effects mediated or modified by the CNS changed in magnesium intoxicated chicks. Such chicks appeared cold and stayed near the heat. When startled, they exhibited extreme avoidance behavior and seizures similar to epilepsy and/or Cl deficiency. Brain tissue Mg content did not concomitantly increase. Whether these effects are due to central signals is unclear.

  10. Deleterious effects of diluted povidone-iodine on articular cartilage.

    PubMed

    von Keudell, Arvind; Canseco, Jose A; Gomoll, Andreas H

    2013-06-01

    A recent study has suggested that irrigation with povidone-iodine solution after knee arthroplasty significantly decreases rates of post-operative surgical site infection. However, there is only limited knowledge of potential chondrotoxic effects on the residual cartilage in patients with partial knee arthroplasties or unresurfaced patella in total knee arthroplasty. Macroscopically normal bovine cartilage explants (n=42) were exposed to different povidone-iodine concentrations for 1, 3 or 6 min, as well as saline control. The viability of superficial chondrocytes was measured by a Live/Dead cytotoxicity assay. Chondrotoxicity correlated positively with the length of exposure, regardless of the concentration. The extent of superficial chondrocyte death was significantly greater at higher concentrations of povidone-iodine solutions. 0.35% povidone-iodine solution was the least chondrotoxic of all concentrations, but still reduced cell viability significantly if applied for longer than 1 min. Our data suggest that povidone-iodine solution at all tested concentrations has a pronounced chondrotoxic effect on the superficial cartilage layer when used for time periods longer than 1 min. PMID:23528554

  11. Potential Deleterious Effects of Vasopressin in Chronic Kidney Disease and Particularly Autosomal Dominant Polycystic Kidney Disease

    Microsoft Academic Search

    E. Meijer; W. E. Boertien; R. Zietse; R. T. Gansevoort

    2011-01-01

    The antidiuretic hormone vasopressin is crucial for regulating free water clearance in normal physiology. However, it has also been hypothesized that vasopressin has deleterious effects on the kidney. Vasopressin is elevated in animals and patients with chronic kidney disease. Suppression of vasopressin activity reduces proteinuria, renal hypertrophy, glomerulosclerosis and tubulointerstitial fibrosis in animal models. The potential detrimental influence of vasopressin

  12. Deleterious effects by mosquitofish (Gambusia affinis) on the endangered fire salamander (Salamandra

    E-print Network

    Blaustein, Leon

    Deleterious effects by mosquitofish (Gambusia affinis) on the endangered fire salamander of amphibians and other aquatic fauna. The mosquito- fish, Gambusia affinis, commonly stocked into amphibian, as is the case of stocking the mosquitofish Gambusia affinis (Courtenay & Meffe, 1989). Introduced biological

  13. Relative Effectiveness of Mating Success and Sperm Competition at Eliminating Deleterious Mutations in

    E-print Network

    Sokolowski, Marla

    Mutations in Drosophila melanogaster. PLoS ONE 7(5): e37351. doi:10.1371/journal.pone.0037351 Editor in Drosophila melanogaster Sean C. A. Clark*, Nathaniel P. Sharp, Locke Rowe, Aneil F. Agrawal Department effects of pre- and postcopulatory sexual selection on deleterious mutations. We used the Drosophila

  14. New Estimates of the Rates and Effects of Mildly Deleterious Mutation in Drosophila melanogaster

    Microsoft Academic Search

    James D. Fry; Peter D. Keightley; Stefanie L. Heinsohn; Sergey V. Nuzhdin

    1999-01-01

    The genomic rate and distribution of effects of deleterious mutations are important parameters in evolutionary theory. The most detailed information comes from the work of Mukai and Ohnishi, who allowed mutations to accumulate on Drosophila melanogaster second chromosomes, shielded from selection and recombination by being maintained heterozygous in males. Averaged over studies, the estimated rate of nonlethal viability mutations per

  15. Deleterious effects of nonthermal electrons in shock ignition concept

    NASA Astrophysics Data System (ADS)

    Nicolaï, Ph.; Feugeas, J.-L.; Touati, M.; Ribeyre, X.; Gus'kov, S.; Tikhonchuk, V.

    2014-03-01

    Shock ignition concept is a promising approach to inertial confinement fusion that may allow obtaining high fusion energy gains with the existing laser technology. However, the spike driving laser intensities in the range of 1-10 PW/cm2 produces the energetic electrons that may have a significant effect on the target performance. The hybrid numerical simulations including a radiation hydrodynamic code coupled to a rapid Fokker-Planck module are used to asses the role of hot electrons in the shock generation and the target preheat in the time scale of 100 ps and spatial scale of 100 ?m. It is shown that depending on the electron energy distribution and the target density profile the hot electrons can either increase the shock amplitude or preheat the imploding shell. In particular, the exponential electron energy spectrum corresponding to the temperature of 30 keV in the present HiPER target design preheats the deuterium-tritium shell and jeopardizes its compression. Ways of improving the target performance are suggested.

  16. Brief report: Labelling effects on the perceived deleterious consequences of pop music listening.

    PubMed

    North, Adrian C; Hargreaves, David J

    2005-06-01

    Several correlational studies have supported the claim of conservative protestors that there exists a positive relationship between listening to pop music and adolescent problem behaviours. However, research on the so-called 'prestige effects' has shown that experimental participants' responses to music can be mediated by manipulations of prior information concerning that music. This study investigated whether perceptions of deleterious effects of pop songs on listeners may be attributable to prior labelling of those stimuli as 'problem music'. Eighty undergraduates were played songs that they were told were either suicide-inducing or life-affirming. Subsequent ratings of the songs indicated that those presented as 'suicide-inducing' were perceived as such, whereas presentation of the same songs in a 'life-affirming' frame led to the perception of them as such. These findings indicate that censorship and the subsequent labelling of certain songs as 'problematic' might itself cause these songs to have deleterious effects on listeners. PMID:15925693

  17. The effect of pathogens on selection against deleterious mutations in Drosophila melanogaster

    Microsoft Academic Search

    JADENE A. YOUNG; CHRISTOPHER P. YOURTH; ANEIL F. AGRAWAL

    2009-01-01

    In natural populations, fitness is reduced by both deleterious mutations and parasites. Few studies have examined interactions between these two factors, particularly at the level of individual genes. We examined how the presence of a bacterial pathogen, Pseudomonas aeruginosa, affected the selection against each of eight deleterious mutations in Drosophila melanogaster. We found that mutations tended to become more deleterious

  18. Deleterious effect of CTLA4-Ig on a Treg-dependent transplant model.

    PubMed

    Riella, L V; Liu, T; Yang, J; Chock, S; Shimizu, T; Mfarrej, B; Batal, I; Xiao, X; Sayegh, M H; Chandraker, A

    2012-04-01

    Blockade of the B7:CD28 costimulatory pathway has emerged as a promising therapy to prevent allograft rejection. However, results from the belatacept phase III clinical trial demonstrated a higher rejection rate when compared to cyclosporine, raising concern about potential deleterious effects of this agent. In this study, we investigated the consequences of B7:CD28 blockade by hCTLA4Ig on regulator T cell (Treg) generation in different major histocompatibility complex (MHC) mismatch transplant models. Administration of hCTLA4Ig significantly decreased the amount of Tregs in B6 WT animals and this effect was predominant in thymus-induced Tregs (Helios(+) ). Although hCTLA4Ig prevented rejection in a fully allogeneic mismatch model, it accelerated rejection in a MHC class-II mismatch model (MST = 26, p < 0.0001), in which long-term allograft survival is dependent on Tregs. This accelerated rejection was associated with a marked reduction in thymus-induced Tregs and led to a higher effector/regulatory T-cell ratio in secondary lymphoid organs and in the allograft. This study confirms the importance of the B7:CD28 pathway in Treg homeostasis in an in vivo transplant model and suggests that hCTLA4Ig therapy may be deleterious in circumstances where engraftment is dependent on Tregs. PMID:22300534

  19. 4-Hydroxytamoxifen induces slight uncoupling of mitochondrial oxidative phosphorylation system in relation to the deleterious effects of tamoxifen

    Microsoft Academic Search

    Carla M. P Cardoso; António J. M Moreno; Leonor M Almeida; José B. A Custódio

    2002-01-01

    The use of tamoxifen (TAM) has been questioned on the chemotherapy and chemoprevention of breast cancer due to several estrogen receptor-independent cytotoxic effects. As an alternative, its more active metabolite 4-hydroxytamoxifen (OHTAM) has been proposed with presumed lower side effects. In this work, the potential OHTAM toxicity on rat liver mitochondrial bioenergetics in relation to the multiple deleterious effects of

  20. No evidence that selection has been less effective at removing deleterious mutations in Europeans than in Africans.

    PubMed

    Do, Ron; Balick, Daniel; Li, Heng; Adzhubei, Ivan; Sunyaev, Shamil; Reich, David

    2015-02-01

    Non-African populations have experienced size reductions in the time since their split from West Africans, leading to the hypothesis that natural selection to remove weakly deleterious mutations has been less effective in the history of non-Africans. To test this hypothesis, we measured the per-genome accumulation of nonsynonymous substitutions across diverse pairs of populations. We find no evidence for a higher load of deleterious mutations in non-Africans. However, we detect significant differences among more divergent populations, as archaic Denisovans have accumulated nonsynonymous mutations faster than either modern humans or Neanderthals. To reconcile these findings with patterns that have been interpreted as evidence of the less effective removal of deleterious mutations in non-Africans than in West Africans, we use simulations to show that the observed patterns are not likely to reflect changes in the effectiveness of selection after the populations split but are instead likely to be driven by other population genetic factors. PMID:25581429

  1. Deleterious effects of maternal ingestion of cocoa upon fetal ductus arteriosus in late pregnancy

    PubMed Central

    Zielinsky, Paulo; Martignoni, Felipe V.; Vian, Izabele

    2014-01-01

    Cocoa powder has twice more antioxidants than red wine and three times more than green tea. Ten percent of its weight is made up of flavonoids. Cocoa has antioxidant and anti-inflammatory effects by downregulating cyclooxigenase-2 receptors expression in the endothelium and enhancing nitric oxide bioavailability. There are evidences that while polyphenols ingestion have cardioprotective effects in the adult, it may have deleterious effect on the fetus if ingested by the mother on the third trimester of pregnancy, causing intrauterine fetal ductus arteriosus (DA) constriction. Polyphenols present in many foods and their anti-inflammatory and antinociceptive activities have been shown to be as or more powerful than those of indomethacin. These effects are dependent on the inhibition of modulation of the arachidonic acid and the synthesis of prostaglandins, especially E-2, which is responsible for fetal DA patency. So, we hypothesized that this same mechanism is responsible for the harmful effect of polyphenol-rich foods, such as cocoa, upon the fetal DA after maternal intake of such substances in the third trimester of pregnancy, thereby rising the perspective of a note of caution for pregnant women diet. PMID:25566077

  2. Deleterious Effects of Amyloid b Oligomers Acting as an Extracellular Scaffold for mGluR5

    E-print Network

    Contractor, Anis

    Neuron Article Deleterious Effects of Amyloid b Oligomers Acting as an Extracellular Scaffold for m.L.K.) DOI 10.1016/j.neuron.2010.04.029 SUMMARY Soluble oligomers of amyloid b (Ab) play a role in the memory impairment characteristic of Alzheimer's disease. Acting as pathogenic ligands, Ab oligomers bind

  3. The quantum Zeno effect immunizes the avian compass against the deleterious effects of exchange and dipolar interactions.

    PubMed

    Dellis, A T; Kominis, I K

    2012-03-01

    Magnetic-sensitive radical-ion-pair reactions are understood to underlie the biochemical magnetic compass used by avian species for navigation. Recent experiments have provided growing evidence for the radical-ion-pair magnetoreception mechanism, while recent theoretical advances have unravelled the quantum nature of radical-ion-pair reactions, which were shown to manifest a host of quantum-information-science concepts and effects, like quantum measurement, quantum jumps and the quantum Zeno effect. We here show that the quantum Zeno effect provides for the robustness of the avian compass mechanism, and immunizes its magnetic and angular sensitivity against the deleterious and molecule-specific exchange and dipolar interactions. PMID:22142839

  4. Erythropoietin promotes deleterious cardiovascular effects and mortality risk in a rat model of chronic sports doping.

    PubMed

    Piloto, Nuno; Teixeira, Helena M; Teixeira-Lemos, Edite; Parada, Belmiro; Garrido, Patrícia; Sereno, José; Pinto, Rui; Carvalho, Lina; Costa, Elísio; Belo, Luís; Santos-Silva, Alice; Teixeira, Frederico; Reis, Flávio

    2009-12-01

    Athletes who abuse recombinant human erythropoietin (rhEPO) consider only the benefit to performance and usually ignore the potential short and long-term liabilities. Elevated haematocrit and dehydratation associated with intense exercise may reveal undetected cardiovascular risk, but the mechanisms underlying it remain to be fully explained. This study aimed to evaluate the cardiovascular effects of rhEPO in rats under chronic aerobic exercise. A ten week protocol was performed in four male Wistar rat groups: control--sedentary; rhEPO--50 IU kg(-1), 3 times/wk; exercised (EX)--swimming for 1 h, 3 times/wk; EX + rhEPO. One rat of the EX + rhEPO group suffered a sudden death episode during the week 8. rhEPO in trained rats promoted erythrocyte count increase, hypertension, heart hypertrophy, sympathetic and serotonergic overactivation. The suddenly died rat's tissues presented brain with vascular congestion; left ventricular hypertrophy, together with a "cardiac-liver", suggesting the hypothesis of heart failure as cause of sudden death. In conclusion, rhEPO doping in rats under chronic exercise promotes not only the expected RBC count increment, suggesting hyperviscosity, but also other serious deleterious cardiovascular and thromboembolic modifications, including mortality risk, which might be known and assumed by all sports authorities, including athletes and their physicians. PMID:19859831

  5. Estimation of the rate and effects of deleterious genomic mutations in finite populations with linkage disequilibrium.

    PubMed

    Li, J; Deng, H-W

    2005-07-01

    Under several assumptions such as infinite population size with unlinked loci at linkage equilibrium (LD) under mutation-selection (M-S) balance, the rate (U), and the average effects (dominance and selection coefficients h and s) of deleterious genomic mutations (DGM) can be estimated by the Deng-Lynch method in some natural populations. However, all natural populations are finite in size and many of them are not large enough to be considered as approximately infinite. In the absence of an analytical estimation approach to characterize DGM in finite populations, we test the robustness and applicability of the Deng-Lynch method in finite populations with computer simulations. The results indicate that the estimation obtained by the Deng-Lynch method in finite populations with LD is generally robust when population size is greater than 400. With constant mutation effects, in outcrossing populations, the estimates U and ? are unbiased or only slightly upwardly biased, and ? is unbiased for most cases. In highly selfing populations, U and ? are upwardly biased, U is no more than 1.5U and ? is less than 1.1 h, and ? is either unbiased or slightly downwardly biased. With variable mutation effects, U ranges from 0.56 to 0.72U, and s ranges from 1.4 to 1.8s. Generally speaking, with the same finite population size, the estimation in outcrossing populations is better than in highly selfing populations. Given that even the order of the magnitude of the parameters of DMG (U in particular) is controversial, our investigation here may provide a basis for using the Deng-Lynch method to characterize DGM in finite populations of size greater than 400 in the presence of LD. PMID:15931248

  6. Multiple deleterious effects of experimentally aged sperm in a monogamous bird.

    PubMed

    White, Joël; Wagner, Richard H; Helfenstein, Fabrice; Hatch, Scott A; Mulard, Hervé; Naves, Liliana C; Danchin, Etienne

    2008-09-16

    Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations. PMID:18779581

  7. Multiple deleterious effects of experimentally aged sperm in a monogamous bird

    USGS Publications Warehouse

    White, J.; Wagner, R.H.; Helfenstein, F.; Hatch, S.A.; Mulard, Hervé; Naves, L.C.; Danchin, E.

    2008-01-01

    Sperm aging is known to be detrimental to reproductive performance. However, this apparently general phenomenon has seldom been studied in an evolutionary context. The negative impact of sperm aging on parental fitness should constitute a strong selective pressure for adaptations to avoid its effects. We studied the impact of sperm aging on black-legged kittiwakes (Rissa tridactyla), a monogamous seabird. Kittiwakes comprise a model system because (i) of evidence that females eject their mates' sperm to prevent fertilization by sperm that would be old and degraded by the time of fertilization and result in reduced reproductive performance and (ii) the lack of extra-pair fertilization in this species makes cryptic female choice an unlikely explanation of postcopulatory sperm ejection by females. We experimentally manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively affected four sequential stages of reproduction: fertilization potential, rate of embryonic development, embryonic mortality, and chick condition at hatching. These results may be produced by a continuum of a single process of sperm aging that differentially affects various aspects of development, depending on the degree of damage incurred to the spermatozoa. The marked impact of sperm age on female fitness may thus drive postcopulatory sperm ejection by females. These results provide experimental evidence of deleterious effects of sperm aging on a nondomestic vertebrate, underlining its taxonomic generality and its potential to select for a wide array of adaptations. ?? 2008 by The National Academy of Sciences of the USA.

  8. Guard crabs alleviate deleterious effects of vermetid snails on a branching coral

    NASA Astrophysics Data System (ADS)

    Stier, A. C.; McKeon, C. S.; Osenberg, C. W.; Shima, J. S.

    2010-12-01

    Stony corals provide important structural habitat for microbes, invertebrates, and fishes, which in some cases has led to the evolution of beneficial interactions that may protect corals from environmental factors such as thermal stress, nutrient limitation, competitors, or predators. For example, guard crabs ( Trapezia spp.) protect corals ( Pocillopora sp.) from attacks by crown-of-thorn seastar and sedimentation. Here, a field experiment demonstrates that guard crabs ( Trapezia serenei) also ameliorate the strong negative effects of the giant vermetid ( Dendropoma maximum) on growth of Pocillopora. This experiment highlights the importance of this crab-coral mutualism: guard crabs facilitate the growth of corals in stressful environments (e.g., where vermetids are abundant), thereby preserving the ecological goods and services (e.g., food and shelter) that these corals may provide to other reef-associated species.

  9. Duration of sexual harassment and generalized harassment in the workplace over ten years: effects on deleterious drinking outcomes.

    PubMed

    McGinley, Meredith; Richman, Judith A; Rospenda, Kathleen M

    2011-01-01

    Although harassment in the workplace has been linked to deleterious drinking outcomes, researchers have yet to examine the long-term effects of chronic workplace harassment. During a 10-year longitudinal mail survey, university employees (N = 2,265) were administered measures of sexual harassment, generalized workplace harassment, and problematic drinking. Using growth mixture modeling, two latent classes of workplace harassment emerged: infrequent and chronic. Demographic characteristics (gender, age, and race) predicted the shape of the trajectories and likelihood of class membership. As hypothesized, membership in the chronic harassment classes was linked to future problematic drinking, even after controlling for previous drinking. PMID:21745045

  10. Comparison of the deleterious effects of binge drinking-like alcohol exposure in adolescent and adult mice.

    PubMed

    Lacaille, Hélène; Duterte-Boucher, Dominique; Liot, Donovan; Vaudry, Hubert; Naassila, Mickael; Vaudry, David

    2015-03-01

    A major cause of alcohol toxicity is the production of reactive oxygen species generated during ethanol metabolism. The aim of this study was to compare the effect of binge drinking-like alcohol exposure on a panel of genes implicated in oxidative mechanisms in adolescent and adult mice. In adolescent animals, alcohol decreased the expression of genes involved in the repair and protection of oxidative DNA damage such as atr, gpx7, or nudt15 and increased the expression of proapoptotic genes such as casp3. In contrast, in the adult brain, genes activated by alcohol were mainly associated with protective mechanisms that prevent cells from oxidative damage. Whatever the age, iterative binge-like episodes provoked the same deleterious effects as those observed after a single binge episode. In adolescent mice, multiple binge ethanol exposure substantially reduced neurogenesis in the dentate gyrus and impaired short-term memory in the novel object and passive avoidance tests. Taken together, our results indicate that alcohol causes deleterious effects in the adolescent brain which are distinct from those observed in adults. These data contribute to explain the greater sensitivity of the adolescent brain to alcohol toxicity. The effects of alcohol exposure were investigated on genes involved in oxidative mechanisms. In adolescent animals, alcohol decreased the expression of genes involved in DNA repair, a potential cause of the observed decrease of neurogenesis. In contrast, in the adult brain, alcohol increased the expression of genes associated with antioxidant mechanisms. Apoptosis was increase in all groups and converged with other biochemical alterations to enhance short-term memory impairment in the adolescent brain. These data contribute to explain the greater sensitivity of the adolescent brain to alcohol toxicity. PMID:25556946

  11. Tongue-placed tactile biofeedback suppresses the deleterious effects of muscle fatigue on joint position sense at the ankle

    E-print Network

    Vuillerme, Nicolas; Chenu, Olivier; Demongeot, Jacques; Payan, Yohan

    2007-01-01

    Whereas the acuity of the position sense at the ankle can be disturbed by muscle fatigue, it recently also has been shown to be improved, under normal ankle neuromuscular state, through the use of an artificial tongue-placed tactile biofeedback. The underlying principle of this biofeedback consisted of supplying individuals with supplementary information about the position of their matching ankle position relative to their reference ankle position through electrotactile stimulation of the tongue. Within this context, the purpose of the present experiment was to investigate whether this biofeedback could mitigate the deleterious effect of muscle fatigue on joint position sense at the ankle. To address this objective, sixteen young healthy university students were asked to perform an active ankle-matching task in two conditions of No-fatigue and Fatigue of the ankle muscles and two conditions of No-biofeedback and Biofeedback. Measures of the overall accuracy and the variability of the positioning were determin...

  12. The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

    PubMed Central

    Mitwally, Mohamed FM; Casper, Robert F; Diamond, Michael P

    2005-01-01

    Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality. PMID:16202169

  13. Alkylating chemotherapy may exert a uniquely deleterious effect upon neo-antigen-targeting anticancer vaccination

    PubMed Central

    Litterman, Adam J; Dudek, Arkadiusz Z; Largaespada, David A

    2013-01-01

    Alkylating chemotherapy exerts both antineoplastic and immunostimulatory effects. However, in addition to depleting regulatory T cells (Treg), alkylating agents also mediate a long lasting antiproliferative effect on responder lymphocytes. Our recent findings indicate that this antiproliferative effect profoundly impairs vaccination-induced immune responses, especially in the case of vaccines that target specific tumor-associated neo-antigens that do not require Treg depletion. PMID:24251080

  14. Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring.

    PubMed

    Gribble, Kristin E; Jarvis, George; Bock, Martha; Mark Welch, David B

    2014-08-01

    While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span. PMID:24661622

  15. Maternal caloric restriction partially rescues the deleterious effects of advanced maternal age on offspring

    PubMed Central

    Gribble, Kristin E; Jarvis, George; Bock, Martha; Mark Welch, David B

    2014-01-01

    While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span. PMID:24661622

  16. The Stigma of Mental Illness and its Deleterious Effects on Psychiatric Treatment and Recovery

    Microsoft Academic Search

    Ashley Doty

    2006-01-01

    In spite of the 1960s social justice movements, discrimination against the mentally ill remains a pervasive problem. The stigma that routinely accompanies the diagnosis of a mental disorder prevents victims suffering in silence from seeking treatment and inhibits the recovery of those patients who have already been diagnosed. This paper examines the nature of this prejudice and its tangible effects,

  17. Brief Report: Labelling Effects on the Perceived Deleterious Consequences of Pop Music Listening

    ERIC Educational Resources Information Center

    North, A.C.; Hargreaves, D.J.

    2005-01-01

    Several correlational studies have supported the claim of conservative protestors that there exists a positive relationship between listening to pop music and adolescent problem behaviours. However, research on the so-called 'prestige effects' has shown that experimental participants' responses to music can be mediated by manipulations of prior…

  18. Genistein Induces Deleterious Effects during Its Acute Exposure in Swiss Mice

    PubMed Central

    Singh, Prabhat; Sharma, Sharad; Kumar Rath, Srikanta

    2014-01-01

    Genistein is a soy derived isoflavone. It has wide variety of therapeutic effects against certain diseases including cancer. Although toxic effects of genistein have been studied, its effect on the gene expression and the reason behind toxicity have not been identified yet. In the present study, genistein was administered to age and body weight matched Swiss mice at the doses of 125, 250, 500 and 1000?mg/kg. The biomarkers of hepatotoxicity in serum, liver histology, oxidative stress parameters in tissue homogenates, and global gene expression were examined. Elevated alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) levels and degenerated liver tissue were observed in 500, and 1000?mg/kg genistein treated groups. Oxidative stress was significant at these doses as considerable increase in lipid peroxidation (LPO) and decrease in total glutathione (GSH) were observed. Gene expression analysis showed 40 differentially expressed genes at twofold change and P < 0.05. Differentially expressed genes were corresponding to different biologically relevant pathways including metabolic and oxidative stress pathways. In 500?mg/kg group, Cyp4a14, Sult1e1, Gadd45g, Cidec, Mycs, and so forth genes were upregulated. These results suggested that the higher dose of genistein can produce several undesirable effects by affecting multiple cellular pathways. PMID:24967385

  19. Deleterious effects of cypermethrin on semen characteristics and testes of dwarf goats ( Capra hircus)

    Microsoft Academic Search

    Maqbool Ahmad; Ijaz Hussain; Ahrar Khan; Najib-ur-Rehman

    2009-01-01

    This study was carried out on 30 male dwarf goats to determine the effects of cypermethrin (CY) on semen characteristics and at tissue level in testes. Animals were divided randomly into five equal groups and each group was dipped with 0%, 0.1%, 0.4%, 0.8% or 1.6% CY, on days 0 and 15. The semen was collected at day 0, then

  20. Mechanisms of the Deleterious Effects of Tamoxifen on Mitochondrial Respiration Rate and Phosphorylation Efficiency

    Microsoft Academic Search

    Carla M. P. Cardoso; José B. A. Custódio; Leonor M. Almeida; António J. M. Moreno

    2001-01-01

    Tamoxifen (TAM), the widely prescribed drug in the prevention and therapy of breast cancer, is a well-known modulator of estrogen receptor (ER) that also inhibits the proliferation of different cell types that lack the ER. However, the ER-independent action mechanisms of TAM and its side effects have not been yet clarified. Mitochondria are essential in supporting the energy-dependent regulation of

  1. Poloxomer 188 Has a Deleterious Effect on Dystrophic Skeletal Muscle Function

    PubMed Central

    Terry, Rebecca L.; Kaneb, Hannah M.; Wells, Dominic J.

    2014-01-01

    Duchenne muscular dystrophy (DMD) is an X-linked, fatal muscle wasting disease for which there is currently no cure and limited palliative treatments. Poloxomer 188 (P188) is a tri-block copolymer that has been proposed as a potential treatment for cardiomyopathy in DMD patients. Despite the reported beneficial effects of P188 on dystrophic cardiac muscle function, the effects of P188 on dystrophic skeletal muscle function are relatively unknown. Mdx mice were injected intraperitoneally with 460 mg/kg or 30 mg/kg P188 dissolved in saline, or saline alone (control). The effect of single-dose and 2-week daily treatment was assessed using a muscle function test on the Tibialis Anterior (TA) muscle in situ in anaesthetised mice. The test comprises a warm up, measurement of the force-frequency relationship and a series of eccentric contractions with a 10% stretch that have previously been shown to cause a drop in maximum force in mdx mice. After 2 weeks of P188 treatment at either 30 or 460 mg/kg/day the drop in maximum force produced following eccentric contractions was significantly greater than that seen in saline treated control mice (P?=?0.0001). Two week P188 treatment at either dose did not significantly change the force-frequency relationship or maximum isometric specific force produced by the TA muscle. In conclusion P188 treatment increases susceptibility to contraction-induced injury following eccentric contractions in dystrophic skeletal muscle and hence its suitability as a potential therapeutic for DMD should be reconsidered. PMID:24642557

  2. Deleterious effects of cypermethrin on semen characteristics and testes of dwarf goats (Capra hircus).

    PubMed

    Ahmad, Maqbool; Hussain, Ijaz; Khan, Ahrar; Najib-ur-Rehman

    2009-07-01

    This study was carried out on 30 male dwarf goats to determine the effects of cypermethrin (CY) on semen characteristics and at tissue level in testes. Animals were divided randomly into five equal groups and each group was dipped with 0%, 0.1%, 0.4%, 0.8% or 1.6% CY, on days 0 and 15. The semen was collected at day 0, then fortnightly till 75 days and evaluated for physical characteristics, sperm morphology and concentration. None of the parameters studied showed any statistical difference on days 0 and 15 of sample collection. From day 30, effect of CY on semen characteristics started to appear and was more pronounced from days 45 to 75. Significantly (P<0.01) decreased ejaculatory volume, motility percentage, mass activity, and concentration of spermatozoa were observed in treated groups as compared to control. With the treatment of CY, pH of semen became more alkaline. Semen color changed from creamy (control) to milky white to straw color in treated bucks. Percentage of abnormal spermatozoa (tailless, bent tails, coiled tailed) was much higher in treated animals than in control. Dead spermatozoa increased significantly (P<0.01) in the treatment groups from days 30 to 75 as compared to the control group. All these changes were dose dependent, being less with low CY dose and more even extensive with high CY dose. Slight to moderate improvement in the above parameters was observed at day 75 nearly in all treated groups. Grossly decreased weight of testis and cyanotic epididymides were observed in bucks treated with 1.6% CY. Histopathologically, degenerative changes and loss of spermatogonia, spermatocyte, Sertoli cells, spermatids, and spermatozoa in seminiferous tubules were also dose dependent. It was concluded that CY caused dose-dependent effects on all parameters studied. High doses of CY (0.8% and 1.6% solution) affected the parameters on semen characteristics, though this effect seems to be transient as improvement in these parameters was observed at day 75; however, CY in goats should be used with great care to avoid over-dosage. PMID:19019642

  3. Zinc therapy improves deleterious effects of chronic copper administration on mice testes: histopathological evaluation.

    PubMed

    Kheirandish, R; Askari, N; Babaei, H

    2014-03-01

    This study was set to investigate whether the adverse effects of long-term copper (Cu) consumption on testicular tissue could be prevented by zinc (Zn) administration. Forty-five mature male mice were randomly divided into one control and two treatment groups. The first treatment group received copper sulphate (Cu experimental group). The second treatment group was given combined treatment of copper sulphate and zinc sulphate (ZC experimental group). Control animals received normal saline using the same volume. Five mice from each group were sacrificed on day 14, 28 and 56 from the beginning of treatments. Left testes were removed for histopathological and histomorphometrical evaluations. Morphometrically, the diameter of seminiferous tubules and Sertoli cell nuclei, epithelial height, meiotic index and the percentage of spermatogenesis in Cu groups showed significant decrease compared to those of the control groups (P < 0.05). A partial improvement was seen in the percentage of spermatogenesis and meiotic index (P < 0.05) in ZC groups, whereas a complete recovery was observed in the rest of parameters in ZC group after 56 days compared to the control group (P > 0.05). Results showed that long-term administration of Cu leads to histological impairments of testis and zinc supplementation might offset these damaging effects. PMID:23137167

  4. BCG and BCG/DNAhsp65 Vaccinations Promote Protective Effects without Deleterious Consequences for Experimental Autoimmune Encephalomyelitis

    PubMed Central

    Zorzella-Pezavento, Sofia Fernanda Gonçalves; Guerino, Clara Pires Fujiara; Chiuso-Minicucci, Fernanda; França, Thais Graziela Donegá; Ishikawa, Larissa Lumi Watanabe; Masson, Ana Paula; Silva, Célio Lopes; Sartori, Alexandrina

    2013-01-01

    A prime-boost strategy conserving BCG is considered the most promising vaccine to control tuberculosis. A boost with a DNA vaccine containing the mycobacterial gene of a heat shock protein (pVAXhsp65) after BCG priming protected mice against experimental tuberculosis. However, anti-hsp65 immunity could worsen an autoimmune disease due to molecular mimicry. In this investigation, we evaluated the effect of a previous BCG or BCG/pVAXhsp65 immunization on experimental autoimmune encephalomyelitis (EAE) development. Female Lewis rats were immunized with BCG or BCG followed by pVAXhsp65 boosters. The animals underwent EAE induction and were daily evaluated for weight loss and clinical score. They were euthanized during recovery phase to assess immune response and inflammatory infiltration at the central nervous system. Previous immunization did not aggravate or accelerate clinical score or weight loss. In addition, this procedure clearly decreased inflammation in the brain. BCG immunization modulated the host immune response by triggering a significant reduction in IL-10 and IFN-? levels induced by myelin basic protein. These data indicated that vaccination protocols with BCG or BCG followed by boosters with pVAXhsp65 did not trigger a deleterious effect on EAE evolution. PMID:24288555

  5. Tanshinol Attenuates the Deleterious Effects of Oxidative Stress on Osteoblastic Differentiation via Wnt/FoxO3a Signaling

    PubMed Central

    Yang, Yajun; Su, Yanjie; Wang, Dongtao; Chen, Yahui; Wu, Tie; Li, Gang; Sun, Xuegang

    2013-01-01

    There is now increasing evidence which suggests a pivotal role for oxidative stress in the development and progression of osteoporosis. We confirm herein the protective effects of natural antioxidant Tanshinol against oxidative stress in osteoblastic differentiation and the underlying mechanism. Our results show that hydrogen peroxide (H2O2) leads to accumulation of reactive oxygen species (ROS), decrease in cell viability, cell cycle arrest and apoptosis in a caspase-3-dependent manner, and inhibition of osteoblastic differentiation. Tanshinol reverses these deleterious consequence triggered by oxidative stress. Moreover, under the condition of oxidative stress, Tanshinol suppresses the activation of FoxO3a transcription factor and expressions of its target genes Gadd45a and catalase (CAT) and simultaneously counteracts the inhibition of Wnt signalling and expressions of target genes Axin2, alkaline phosphatase (ALP), and Osteoprotegerin (OPG). The findings are further consolidated using FoxO3a siRNA interference and overexpression of Tcf4. The results illustrate that Tanshinol attenuates oxidative stress via down-regulation of FoxO3a signaling, and rescues the decrease of osteoblastic differentiation through upregulation of Wnt signal under oxidative stress. The present findings suggest that the beneficial effects of Tanshinol may be adopted as a novel therapeutic approach in recently recognized conditions of niche targeting osteoporosis. PMID:24489983

  6. Deleterious effects of traditional Chinese medicine preparations on the course of psoriasis--a case report.

    PubMed

    Pietrzak, Aldona; Bartosi?ska, Joanna; Dreiher, Jacob; Szepietowski, Jacek C; Gawlik-Dziki, Urszula; Maciejewski, Ryszard; Podhorecka, Monika; Chodorowska, Gra?yna

    2013-01-01

    Psoriasis is a chronic, systemic and difficult to treat condition which negatively affects the patient's quality of life. Frustrated and unsatisfied with the conventional therapies, psoriatic patients start looking for alternative treatment which they believe to be safe and effective. Very common traditional Chinese medicine (TCM) appears to offer various topical and systemic herbal preparations, as well as massages, acupuncture, diet and lifestyle alternations. The presented study concerns a 48-year-old female patient with exacerbated psoriatic skin lesions (tending to become erythrodermic), and certain systemic complications that appeared after taking a TCM herbal medication, Fu Fang Quing Dai Wan, as well as the use of a Chinese herbal bath gel and staying on a diet rich in meat. After in vitro examinations were made of the herbal preparation and its biological properties determined, it was concluded that the TCM herbal preparation should not be considered harmless. Therefore, patients should be made aware of its adverse reactions. PMID:24364460

  7. Synergistic deleterious effect of chronic stress and sodium azide in the mouse hippocampus.

    PubMed

    Delgado-Cortés, María José; Espinosa-Oliva, Ana M; Sarmiento, Manuel; Argüelles, Sandro; Herrera, Antonio J; Mauriño, Raquel; Villarán, Ruth F; Venero, José L; Machado, Alberto; de Pablos, Rocío M

    2015-04-20

    Alzheimer's disease is the most common cause of dementia in the elderly. Although the primary cause of the disease is presently unknown, to date several risk factors have been described. Evidence suggests that one of these risk factors could be chronic stress. The aim of this work is to demonstrate that chronic stress is able to induce Alzheimer's disease features after the administration of nontoxic doses of sodium azide. We found that chronic stress increases the levels of several proteins involved in Alzheimer's disease pathogenesis, such as presenilin 1, presenilin 2, and S100?, besides inducing the aggregation of Tau, ubiquitin, and ?-amyloid proteins in the hippocampus. More important, our work shows a synergistic effect of stress and sodium azide treatment leading to significant neuronal death in the mouse hippocampus. Our results point out that chronic stress is a risk factor contributing to amplify and accelerate Alzheimer's disease features in the hippocampus. PMID:25658758

  8. Identification of the Hammerhead Ribozyme Metal Ion Binding Site Responsible for Rescue of the Deleterious Effect of a Cleavage Site Phosphorothioate

    E-print Network

    Herschlag, Dan

    of the Deleterious Effect of a Cleavage Site Phosphorothioate Shenglong Wang,,§ Katrin Karbstein,,§ Alessio Peracchi referred to as the P9/G10.1 site. Although this metal ion binding site is 20 Å away from the cleavage site that the pro-RP oxygen at the cleavage site is coordinated by a metal ion in the reaction's transition state

  9. Genistein attenuates glucocorticoid-induced bone deleterious effects through regulation Eph/ephrin expression in aged mice

    PubMed Central

    Cheng, Yuan; Wang, Wei-Lin; Liang, Jun-Jun

    2015-01-01

    Objective: This study was performed to investigate bone deteriorations and the involvement of skeletal Eph/ephrin signaling pathway of GIOP aged mice in response to the treatment of genistein. Methods: The biomarkers in serum and urine were measured, tibias were taken for the measurement on gene and protein expression and histomorphology analysis, and femurs were taken for the measurement on bone Ca and three-dimensional architecture of trabecular bone. Results: Genistein showed a greater increase in bone Ca, BMD and significantly increased FGF-23 and OCN, reduced TRACP-5b, PTH and CTX in GIOP mice. Genistein reversed DXM-induced trabecular deleterious effects and stimulated bone remodeling. The treatment of DXM group with genistein significantly elevated the ratio of OPG/RANKL. Moreover, genistein administration down-regulated the mRNA and protein expression of Eph A2 and ephrin A2 in tibia of the GIOP mice. In contrast, the mRNA and protein expression of Eph B4 and ephrin B2 were increased in mice treated by DXM with genistein as compared to the DXM single treatment. Conclusions: DXM-induced trabecular bone micro-structure deterioration in aged mice was involved in the regulation of the Eph receptors and ephrin ligands. Genistein might represent a therapy with bone-forming as well as an anti-resorptive activity in GIOP mice. The underlying mechanism was mediated, at least partially, through regulation Eph/ephrin signaling. PMID:25755727

  10. Deleterious Effects of Minocycline after in vivo Target Deprivation of Thalamocortical Neurons in the Immature, Metallothionein-Deficient Mouse Brain

    PubMed Central

    Potter, Emily G.; Cheng, Ying; Natale, JoAnne E.

    2015-01-01

    Compared to adults, immature metallothionein I & II knockout (MT?/?) mice incur greater neuronal loss and a more rapid rate of microglia accumulation following target deprivation-induced injury. Since minocycline has been proposed to inhibit microglial activation and associated production of neuroinflammatory factors, we investigated its ability to promote neuronal survival in the immature, metallothionein-deficient brain. Following ablation of the visual cortex, 10-day-old MT?/? mice were treated with minocycline or saline and sacrificed 24 or 48 hours after injury. Using stereological methods, the number of microglia and neurons were estimated in the ipsilateral dorsal lateral geniculate nucleus (dLGN) by an investigator blinded to the treatment. No effect on neuronal survival was observed at 24 hours, but 48 hours after injury an unanticipated but significant minocycline-mediated increase in neuronal loss was detected. Further, while failing to inhibit microglial accumulation, minocycline treatment increased the proportion of amoeboid microglia in the ipsilateral dLGN. To understand the molecular mechanisms underlying this neurotoxic response, we identified minocycline-mediated changes in the expression of three potentially pro-apoptotic/ inflammatory genes: growth arrest- and DNA damage-inducible gene 45? (GADD45?); interferon-inducible protein 1 (IFI1) and cytokine induced growth factor (CTGF). We also observed increased mitogen-activated protein kinase (MAPK) p38 phosphorylation with minocycline treatment. Although minocycline inhibited calpain activity at 12 hours post-injury, this effect was not sustained at 24 hours. Together, these results help to explain how minocycline has a deleterious effect on neuronal survival in this injury model. PMID:19115404

  11. Deleterious effects of water-soluble fraction of petroleum, diesel and gasoline on marine pejerrey Odontesthes argentinensis larvae.

    PubMed

    Rodrigues, Ricardo Vieira; Miranda-Filho, Kleber Campos; Gusmão, Emeline Pereira; Moreira, Cauê Bonucci; Romano, Luis Alberto; Sampaio, Luís André

    2010-04-01

    Accidental discharges and oil spills are frequent around the world. Petroleum-derived hydrocarbons are considered one of the main pollutants of aquatic ecosystem. The importance of petroleum and refined fuels is notorious because today's society depends on them. Researches related to the toxic water-soluble fraction (WSF) of petroleum and derivatives to aquatic biota are scarce. For this reason, deleterious effects of WSF of Brazilian petroleum, automotive diesel and unleaded gasoline to marine pejerrey Odontesthes argentinensis larvae were studied employing toxicity tests and histopathological examination. Each WSF was generated in a laboratory by mixing four parts of seawater with one part of pollutant by approximately 22 h. Larvae were exposed during 96 h to different concentrations of WSF of petroleum, diesel, and gasoline, plus a control. After 96 h of exposure to the different WSFs, three larvae were sampled for histopathological studies. The median lethal concentration after 96 h (LC50) of exposure for WSF of petroleum was equal to 70.68%, it was significantly higher (P<0.05) than the values for WSF of diesel and gasoline, which were 13.46% and 5.48%, respectively. The histological examination of pejerrey larvae exposed to WSF of petroleum, diesel and gasoline after 96 h revealed a variety of lesions in the larvae. The gills, pseudobranchs and esophagus presented epithelial hyperplasia, and the liver presented dilatation of hepatic sinusoids, hepatocitomegaly, bi-nucleated and nuclear degeneration of hepatocytes, such as pyknotic nuclei. The acute toxicity of diesel and gasoline is at least fivefold higher than Brazilian petroleum. However, all toxicants induced histopathological abnormalities in pejerrey larvae. The results are of importance since much attention has been paid to large visible surfaces of petroleum spills instead of potential toxic effects of dissolved aromatic hydrocarbons, which are more available to marine biota. PMID:20167351

  12. Harnessing Mechanistic Knowledge on Beneficial Versus Deleterious IFN-I Effects to Design Innovative Immunotherapies Targeting Cytokine Activity to Specific Cell Types

    PubMed Central

    Tomasello, Elena; Pollet, Emeline; Vu Manh, Thien-Phong; Uzé, Gilles; Dalod, Marc

    2014-01-01

    Type I interferons (IFN-I) were identified over 50?years ago as cytokines critical for host defense against viral infections. IFN-I promote anti-viral defense through two main mechanisms. First, IFN-I directly reinforce or induce de novo in potentially all cells the expression of effector molecules of intrinsic anti-viral immunity. Second, IFN-I orchestrate innate and adaptive anti-viral immunity. However, IFN-I responses can be deleterious for the host in a number of circumstances, including secondary bacterial or fungal infections, several autoimmune diseases, and, paradoxically, certain chronic viral infections. We will review the proposed nature of protective versus deleterious IFN-I responses in selected diseases. Emphasis will be put on the potentially deleterious functions of IFN-I in human immunodeficiency virus type 1 (HIV-1) infection, and on the respective roles of IFN-I and IFN-III in promoting resolution of hepatitis C virus (HCV) infection. We will then discuss how the balance between beneficial versus deleterious IFN-I responses is modulated by several key parameters including (i) the subtypes and dose of IFN-I produced, (ii) the cell types affected by IFN-I, and (iii) the source and timing of IFN-I production. Finally, we will speculate how integration of this knowledge combined with advanced biochemical manipulation of the activity of the cytokines should allow designing innovative immunotherapeutic treatments in patients. Specifically, we will discuss how induction or blockade of specific IFN-I responses in targeted cell types could promote the beneficial functions of IFN-I and/or dampen their deleterious effects, in a manner adapted to each disease. PMID:25400632

  13. Deleterious effects in mice of fish-associated methylmercury contained in a diet mimicking the Western populations' average fish consumption.

    PubMed

    Bourdineaud, Jean-Paul; Fujimura, Masatake; Laclau, Muriel; Sawada, Masumi; Yasutake, Akira

    2011-02-01

    Methylmercury (MeHg) is a potent neurotoxin, and human beings are mainly exposed to this pollutant through fish consumption. Only a few contradictory epidemiological studies are currently available examining the impact of fish consumption on human populations. In the present study, we wanted to address whether a diet mimicking the fish consumption of Western populations could result in observable adverse effects in mice, and whether beneficial nutriments from fish were able to counterbalance the deleterious effects of MeHg, if any. In Europe and the United States, fish consumption varies widely between countries, from 11 to 100 g fish/day. A mid-range value of 25 g fish/day corresponds to a fish contribution to the total diet of 1.25% on a dry weight basis. We decided to supplement a vegetarian-based mouse diet with 1.25% of lyophilized salmon flesh (SAL diet), or 1.25% of a blend of lyophilized cod, tuna, and swordfish (CTS diet). Total mercury contents were 1.15±0.15, 2.3±0.1 and 35.75±0.15 ng Hg/g of food pellets for the control, SAL and CTS diets, respectively. After two months feeding, the CTS diet resulted in significant observable effects as compared to the control and SAL diets, encompassing decreased body growth, altered behavioral performance and increased anxiety level, modification of mitochondrial respiratory protein subunit concentrations in kidney and brain structures, modified gene expression patterns in kidneys, liver and muscles, and a decrease of dopamine concentrations in the hypothalamus and striatum. Our findings have health implications, firstly because 1.25% of CTS flesh in the diet corresponds to an average exposure to MeHg below the WHO provisory tolerable weekly intake (PTWI) (1.6 ?g MeHg/kg of body weight/week), and secondly because many people in Western populations, among them women of child-bearing age, are exceeding the PTWI value (for instance, 35% of the French population inhabiting the Atlantic and Mediterranean coasts). PMID:21035857

  14. Molecular docking and molecular dynamics study on the effect of ERCC1 deleterious polymorphisms in ERCC1-XPF heterodimer.

    PubMed

    Priya Doss, C George; Nagasundaram, N

    2014-02-01

    Excision repair cross complementation group 1 (ERCC1) is an important protein in the nucleotide excision repair (NER) pathway, which is responsible for removing DNA adducts induced by platinum based compounds. The heterodimer ERCC1-XPF is one of two endonucleases required for NER. Genetic variations or polymorphisms in ERCC1 gene alter DNA repair capacity. Reduced DNA repair (NER) capacity may result in tumors and enhances cisplatin chemotherapy in cancer patients, which functions by causing DNA damage. Therefore, ERCC1 variants have the potential to be used as a strong candidate biomarker in cancer treatments. In this study we identified five variants V116M, R156Q, A199T, S267P, and R322C of ERCC1 gene as highly deleterious. Further structural and functional analysis has been conducted for ERCC1 protein in the presence of three variants V116M, R156Q, and A199T. Occurrence of theses variations adversely affected the regular interaction between ERCC1 and XPF protein. Analysis of 20 ns molecular dynamics simulation trajectories reveals that the predicted deleterious variants altered the ERCC1-XPF complex stability, flexibility, and surface area. Notably, the number of hydrogen bonds in ERCC1-XPF mutant complexes decreased in the molecular dynamic simulation periods. Overall, this study explores the link between the ERCC1 deleterious variants and cisplatin chemotherapy for various cancers with the help of molecular docking and molecular dynamic approaches. PMID:24158589

  15. Nonmicrowave health and ecological effects: Overview

    NASA Technical Reports Server (NTRS)

    White, M. R.

    1980-01-01

    The potential environmental impacts due to the operation and construction of the Satellite Power System are discussed. The nonmicrowave health and ecological effects encompass impacts on the public, the terrestrial worker, the space worker, the ecology, and agriculture.

  16. Neutralizing antibodies obtained in a persistent immune response are effective against deleterious effects induced by the Thalassophryne nattereri fish venom.

    PubMed

    Piran-Soares, Ana Amélia; Komegae, Evilin Naname; Souza, Valdênia Maria Oliveira; Fonseca, Luiz Alberto; Lima, Carla; Lopes-Ferreira, Mônica

    2007-06-01

    Thalassophryne nattereri envenoming represents a great cost to North and Northeast Brazilian communities in terms of public healths, leisure and tourism. Victims rapidally develop symptoms as pain, local swelling, erythema followed by intense necrosis that persist for long days. The aim of this work was tested the immune competence of neutralizing antibodies in pre-immunized mice against principal toxic activities induced by venom. During the primary antibody response in mice, an elevation of IgG antibody levels was only observed on day 28. After boosting, high antibody levels were detected between days 49 and 70, with a 12-fold increase in IgG level over control values at day 49. We confirmed the in vitro neutralizing capacity of T. nattereri anti-venom against toxic effects and thereafter we show that neutralizing antibodies obtained in a persistent immune response are more effective, inclusive against edematous reaction. After boosting during the secondary response mice with high antibody levels do not present any alterations in venule or arteriole after topical application of venom on cremaster muscle. In addition, CK activity diminished in these mice with high neutralizing antibody levels corroborating the attenuation of the myonecrotic effect by venom. In addition, we determined the presence of high IgG antibodies levels in patients 6 months after injury by T. nattereri. In conclusion, the presence of neutralizing antibodies against to T. nattereri venom in the serum of pre-immunized mice could change the outcome of lesion at site of posterior envenoming. Antigen-specific antibodies of high affinity in consequence to specific immune response, dependent of T lymphocyte activation, could minimize the symptoms of intense and immediate inflammatory reaction caused by T. nattereri venom. These finding prompt us to the possibility of development of immune therapeutic strategies using specific anti-venom as an efficient intervention for protecting human victims. PMID:17391720

  17. Testing the Ability of Non-Methylamine Osmolytes Present in Kidney Cells to Counteract the Deleterious Effects of Urea on Structure, Stability and Function of Proteins

    PubMed Central

    Khan, Sheeza; Bano, Zehra; Singh, Laishram R.; Hassan, Md. Imtaiyaz; Islam, Asimul; Ahmad, Faizan

    2013-01-01

    Human kidney cells are under constant urea stress due to its urine concentrating mechanism. It is believed that the deleterious effect of urea is counteracted by methylamine osmolytes (glycine betaine and glycerophosphocholine) present in kidney cells. A question arises: Do the stabilizing osmolytes, non-methylamines (myo-inositol, sorbitol and taurine) present in the kidney cells also counteract the deleterious effects of urea? To answer this question, we have measured structure, thermodynamic stability (?GDo) and functional activity parameters (Km and kcat) of different model proteins in the presence of various concentrations of urea and each non-methylamine osmolyte alone and in combination. We observed that (i) for each protein myo-inositol provides perfect counteraction at 1?2 ([myo-inositol]:[urea]) ratio, (ii) any concentration of sorbitol fails to refold urea denatured proteins if it is six times less than that of urea, and (iii) taurine regulates perfect counteraction in a protein specific manner; 1.5?2.0, 1.2?2.0 and 1.0?2.0 ([taurine]:[urea]) ratios for RNase-A, lysozyme and ?-lactalbumin, respectively. PMID:24039776

  18. Salt Potentiates Methylamine Counteraction System to Offset the Deleterious Effects of Urea on Protein Stability and Function

    PubMed Central

    Singh, Laishram R.; Warepam, Marina; Ahmad, Faizan; Dar, Tanveer Ali

    2015-01-01

    Cellular methylamines are osmolytes (low molecular weight organic compounds) believed to offset the urea’s harmful effects on the stability and function of proteins in mammalian kidney and marine invertebrates. Although urea and methylamines are found at 2:1 molar ratio in tissues, their opposing effects on protein structure and function have been questioned on several grounds including failure to counteraction or partial counteraction. Here we investigated the possible involvement of cellular salt, NaCl, in urea-methylamine counteraction on protein stability and function. We found that NaCl mediates methylamine counteracting system from no or partial counteraction to complete counteraction of urea’s effect on protein stability and function. These conclusions were drawn from the systematic thermodynamic stability and functional activity measurements of lysozyme and RNase-A. Our results revealed that salts might be involved in protein interaction with charged osmolytes and hence in the urea-methylamine counteraction. PMID:25793733

  19. vol. 174, no. 6 the american naturalist december 2009 Selection, Epistasis, and Parent-of-Origin Effects on Deleterious

    E-print Network

    Agrawal, Aneil F.

    vol. 174, no. 6 the american naturalist december 2009 Selection, Epistasis, and Parent of the distribution of selection coeffi- cients and gene interaction effects (epistasis). Although most aspects and epistasis at the level of individual genes, especially in multicellular organisms. Using Drosophila melano

  20. APPLICATION OF 1- METHYLCYCLOPROPENE REVERSES THE DELETERIOUS EFFECT OF EXOGENOUS ETHYLENE ON FRESH-CUT WATERMELON AND CONTROLS MICROBIAL GROWTH

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of exogenous ethylene, 1- methylcyclopropene (1-MCP), or both on microbial growth on watermelon fruit and watermelon slices were investigated. Freshly harvested seedless watermelons (Citrullus lanatus Thunb. Matsum and Nakai, variety Sugar Heart) were treated with 0, 0.5 or 1 ppm 1- MCP,...

  1. Deleterious Effects of Supplementation with Dehydroepiandrosterone Sulphate or Dexamethasone on Rat Insulin-Secreting Cells Under In Vitro Culture Condition

    Microsoft Academic Search

    Hui-Kang Liu; Brian D. Green; Neville H. McClenaghan; Jannie T. McCluskey; Peter R. Flatt

    2006-01-01

    Dehydroepiandrosterone (DHEA) and glucocorticoids are steroid hormones synthesised in the adrenal cortex. Administration of\\u000a DHEA, its sulphate derivative, DHEAS, and more controversially dexamethasone (DEX), a synthetic glucocorticoid, have beneficial\\u000a effects in diabetic animals. Cultivating BRIN-BD11 cells for 3 days with either DHEAS (30 ?M) or DEX (100 nM), reduced total\\u000a cell number and reduced cell viability and cellular insulin content. DHEAS-treated cells had

  2. Unexpected Lack of Deleterious Effects of Uranium on Physiological Systems following a Chronic Oral Intake in Adult Rat

    PubMed Central

    Dublineau, Isabelle; Souidi, Maâmar; Gueguen, Yann; Lestaevel, Philippe; Bertho, Jean-Marc; Manens, Line; Delissen, Olivia; Grison, Stéphane; Paulard, Anaïs; Monin, Audrey; Kern, Yseult; Rouas, Caroline; Loyen, Jeanne; Gourmelon, Patrick; Aigueperse, Jocelyne

    2014-01-01

    Uranium level in drinking water is usually in the range of microgram-per-liter, but this value may be as much as 100 to 1000 times higher in some areas, which may raise question about the health consequences for human populations living in these areas. Our purpose was to improve knowledge of chemical effects of uranium following chronic ingestion. Experiments were performed on rats contaminated for 9 months via drinking water containing depleted uranium (0.2, 2, 5, 10, 20, 40, or 120?mg/L). Blood biochemical and hematological indicators were measured and several different types of investigations (molecular, functional, and structural) were conducted in organs (intestine, liver, kidneys, hematopoietic cells, and brain). The specific sensitivity of the organs to uranium was deduced from nondeleterious biological effects, with the following thresholds (in mg/L): 0.2 for brain, >2 for liver, >10 for kidneys, and >20 for intestine, indicating a NOAEL (No-Observed-Adverse-Effect Level) threshold for uranium superior to 120?m?g/L. Based on the chemical uranium toxicity, the tolerable daily intake calculation yields a guideline value for humans of 1350??g/L. This value was higher than the WHO value of 30??g/L, indicating that this WHO guideline for uranium content in drinking water is very protective and might be reconsidered. PMID:24693537

  3. N-acetylcycsteine attenuates the deleterious effects of radiation therapy on inci-sional wound healing in rats

    PubMed Central

    Tascilar, O; Çakmak, GK; Emre, AU; Bakkal, H; Kandemir, N; Turkcu, UO; Demir, EO

    2014-01-01

    Background: During preoperative radiotherapy, effective doses of ionizing radiation occasionally cause wound complications after subsequent surgery. This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on anastomotic healing of irradiated rats. Material & Methods: Forty Wistar albino rats were randomized into four groups containing 10 rats each. A 3 cm long surgical full-thickness midline laparotomy was performed to all groups (Groups 1-4). Group 1 was designed as a control group without radiation therapy and NAC treatment. Groups 2, 3 and 4 received a single abdominal dose of 10 Gy irradiation before laparotomy and groups 3 and 4 received oral and intraperitoneal NAC, respectively. Results: Group comparisons demonstrated that breaking strength was significantly higher in NAC treated rats. A statistically significant difference was determined in terms of superoxide dismutase (SOD), malondealdehyde (MDA) and glutation (GSH) values between groups (p<0.001). Nevertheless, advanced oxidation protein products (AOPP) levels were found to be similar between groups (p=0.163). Serum GSH and SOD levels were significantly higher in groups 3 and 4 when compared to group 2 (p < 0.05). Similarly, there was a significant increase in serum MDA concentration, predicting lipid peroxidation, in group 2 when compared to groups 1, 3 and 4 (p < 0.05). There was not a significant difference between Groups 3 and 4 regarding GSH, MDA, SOD, and AOPP levels. Histopathological analysis revealed that NAC administration, either orally or intraperitoneally, leads to a better incisional healing in terms of inflammation, granulation, collagen deposition, reepithelization and neovascularization. Conclusion: The present study supports the hypothesis that NAC administration alleviates the negative effects of radiotherapy on incisional wound healing by means of reducing oxidative stress markers and improving histologic parameters independent of the route of administration. PMID:25125946

  4. CpG-C oligodeoxynucleotides limit the deleterious effects of beta-adrenoceptor stimulation on NK cytotoxicity and metastatic dissemination.

    PubMed

    Goldfarb, Yael; Benish, Marganit; Rosenne, Ella; Melamed, Rivka; Levi, Ben; Glasner, Ariella; Ben-Eliyahu, Shamgar

    2009-04-01

    Suppression of natural killer (NK) cell activity is common after stress, has been reported to predict malignant recurrence in cancer patients, and was shown to underlie metastatic dissemination in animal models. We have previously reported that catecholamines play a major role in NK cell suppression, particularly in the context of physiologic stress and surgery. In the current study using Fisher 344 rats, we examined the prophylactic use of different regimens of type-C CpG oligodeoxynucleotides (CpG-C ODN) on NK activity and metastatic dissemination in the context of pharmacologic stress (using metaproterenol for beta-adrenoceptor stimulation). Our results indicated that the beneficial effects of CpG-C ODN were more profound under pharmacologic stress than under baseline conditions. A bolus of CpG-C ODN (330 microg/kg, intraperitoneally) 24 hours before metaproterenol-challenge was most effective at reducing lung tumor retention of an experimental syngeneic mammary adenocarcinoma (MADB106), although having no observable side effects. Depletion of NK cells revealed their key role in improving baseline levels of resistance to metastatic dissemination after CpG-C ODN administration. When NK cell cytotoxicity was assessed in the circulation and the marginating-pulmonary immune compartments, we found that CpG-C ODN protected individual NK cells from metaproterenol-induced suppression in both compartments. Moreover, in the critical marginating-pulmonary compartment, CpG-C ODN also elevated baseline cytotoxicity per NK cell against MADB106 tumor cells, and increased NK cell numbers in nonstressed rats. Overall, prophylactic CpG-C ODN treatment can improve immunocompetence and potentially reduce metastatic dissemination, especially in clinical settings characterized by enhanced sympathetic stress responses. PMID:19242372

  5. Effectiveness of porcine dermal collagen in giant hernia closure in patients with deleterious fascia constitution after orthotopic liver transplantation.

    PubMed

    Werkgartner, Georg; Cerwenka, Herwig; Rappl, Thomas; Kniepeiss, Daniela; Kornprat, Peter; Iberer, Florian; Bacher, Heinz; Wagner, Mathias; Mischinger, Hans J; Wagner, Doris

    2015-02-01

    Incisional hernias (IHs) occur universally after orthotopic liver transplantation (OLT). This study aimed to investigate the effectiveness of porcine dermal collagen (PDC) as a closing aid in giant hernias after OLT in a prospective trial. If direct closure (DC) was not feasible due to the hernia size and abdominal wall constitution, a PDC mesh was implanted. All patients from the PDC and DC groups were followed prospectively for 24 months. IH recurrence rates served as the primary endpoint, and the development of infections and wound healing disorders served as the secondary endpoints. Recurrence rate was 21% (4/19) in DC patients and 12% (2/16) in PDC patients (P = 0.045). Implant site infections occurred in five of PDC and one of DC patients (P < 0.05). All of them were managed with antibiotics; two of the PDC patients required surgical drainage. Histological analysis of PDC mesh biopsies indicated good angiogenesis and integration of the PDC into the abdominal wall. PDC was effective in our study for incisional hernia repair, and our results compared favourably with those of patients in whom direct hernia closure was feasible. PMID:25269850

  6. Deleterious effect of suboptimal diet on rest-activity cycle in Anastrepha ludens manifests itself with age

    PubMed Central

    Chiu, Joanna C.; Kaub, Kevin; Zou, Sige; Liedo, Pablo; Altamirano-Robles, Leopoldo; Ingram, Donald; Carey, James R.

    2013-01-01

    Activity patterns and sleep-wake cycles are among the physiological processes that change most prominently as animals age, and are often good indicators of healthspan. In this study, we used the video-based high-resolution Behavioral Monitoring System (BMS) to monitor the daily activity cycle of tephritid fruit flies Anastrepha ludens over their lifetime. Surprisingly, there was no dramatic change in activity profile with respect to age if flies were consistently fed with a nutritionally balanced diet. However, if flies were fed with sugar-only diet, their activity profile decreased in amplitude at old age, suggesting that suboptimal diet affected activity patterns, and its detrimental effect may not manifest itself until the animal ages. Moreover, by simulating different modes of behavior monitoring with a range of resolution and comparing the resulting conclusions, we confirmed the superior performance of video-based monitoring using high-resolution BMS in accurately representing activity patterns in an insect model. PMID:23639915

  7. Deleterious effects of supplementation with dehydroepiandrosterone sulphate or dexamethasone on rat insulin-secreting cells under in vitro culture condition.

    PubMed

    Liu, Hui-Kang; Green, Brian D; McClenaghan, Neville H; McCluskey, Jannie T; Flatt, Peter R

    2006-02-01

    Dehydroepiandrosterone (DHEA) and glucocorticoids are steroid hormones synthesised in the adrenal cortex. Administration of DHEA, its sulphate derivative, DHEAS, and more controversially dexamethasone (DEX), a synthetic glucocorticoid, have beneficial effects in diabetic animals. Cultivating BRIN-BD11 cells for 3 days with either DHEAS (30 muM) or DEX (100 nM), reduced total cell number and reduced cell viability and cellular insulin content. DHEAS-treated cells had poor glucose responsiveness and regulated insulin release, coupled with reduced basal insulin release. In contrast, DEX-treated cells lacked responsiveness to glucose and membrane depolarisation, and both protein kinase A (PKA) and protein kinase C (PKC) secretory pathways were desensitised. Therefore, we conclude that this steroid hormone and synthetic glucocorticoid are not beneficial to pancreatic beta-cells in vitro. PMID:16779665

  8. Lack of deleterious effect of slow-release sodium fluoride treatment on cortical bone histology and quality in osteoporotic patients

    NASA Technical Reports Server (NTRS)

    Zerwekh, J. E.; Antich, P. P.; Sakhaee, K.; Prior, J.; Gonzales, J.; Gottschalk, F.; Pak, C. Y.

    1992-01-01

    We evaluated the effects of intermittent slow-release sodium fluoride (SRNaF) and continuous calcium citrate therapy on cortical bone histology, reflection ultrasound velocity (material strength) and back-scattered electron image analysis (BEI) in 26 osteoporotic patients before and following therapy. All measurements were made on transiliac crest bone biopsies obtained before and following 2 years of therapy in each patient. For all 26 patients there were no significant changes in cortical bone histomorphometric parameters. In 15 patients in whom bone material quality was assessed by reflection ultrasound, there was no change in velocity (4000 +/- 227 SD to 4013 +/- 240 m/s). BEI disclosed no mineralization defects or the presence of woven bone. Mean atomic number (density) of bone increased slightly, but significantly (9.261 +/- 0.311 to 9.457 +/- 0.223, P = 0.031). While these changes are less marked than those observed for cancellous bone, they indicate that this form of therapy does not adversely affect cortical bone remodelling.

  9. Ecological Engineering Practices for the Reduction of Excess Nitrogen in Human-Influenced Landscapes: A Guide for Watershed Managers

    EPA Science Inventory

    Excess nitrogen (N) in freshwater systems, estuaries, and coastal areas has well-documented deleterious effects on ecosystems. Ecological engineering practices (EEPs) may be effective at decreasing nonpoint source N leaching to surface and groundwater. However, few studies have s...

  10. Deleterious effects of reactive metabolites

    PubMed Central

    2010-01-01

    A number of drugs have been withdrawn from the market or severely restricted in their use because of unexpected toxicities that become apparent only after the launch of new drug entities. Circumstantial evidence suggests that, in most cases, reactive metabolites are responsible for these unexpected toxicities. In this review, a general overview of the types of reactive metabolites and the consequences of their formation are presented. The current approaches to evaluate bioactivation potential of new compounds with particular emphasis on the advantages and limitation of these procedures will be discussed. Reasonable reasons for the excellent safety record of certain drugs susceptible to bioactivation will also be explored and should provide valuable guidance in the use of reactive-metabolite assessments when nominating drug candidates for development. This will, in turn, help us to design and bring safer drugs to the market. PMID:20972370

  11. EEG theta/beta ratio as a potential biomarker for attentional control and resilience against deleterious effects of stress on attention.

    PubMed

    Putman, Peter; Verkuil, Bart; Arias-Garcia, Elsa; Pantazi, Ioanna; van Schie, Charlotte

    2014-06-01

    Anxious stress compromises cognitive executive performance. This occurs, for instance, in cognitive performance anxiety (CPA), in which anxiety about one's cognitive performance causes that performance to actually deteriorate (e.g., test anxiety). This is thought to result from a prefrontal cortically (PFC) mediated failure of top-down attentional control over stress-induced automatic processing of threat-related information. In addition, stress-induced increased catecholamine influx into the PFC may directly compromise attentional function. Previous research has suggested that the ratio between resting state electroencephalographic (EEG) low- and high-frequency power (the theta/beta ratio) is related to trait attentional control, which might moderate these effects of stress on attentional function. The goals of the present study were to test the novel prediction that theta/beta ratio moderates the deleterious effects of CPA-like anxious stress on state attentional control and to replicate a previous finding that the theta/beta ratio is related to self-reported trait attentional control. After recording of baseline frontal EEG signals, 77 participants performed a stress induction or a control procedure. Trait attentional control was assessed with the Attentional Control Scale, whereas stress-induced changes in attentional control and anxiety were measured with self-report visual analogue scales. The hypothesized moderating influence of theta/beta ratio on the effects of stress on state attentional control was confirmed. Theta/beta ratio explained 28% of the variance in stress-induced deterioration of self-reported attentional control. The negative relationship between theta/beta ratio and trait attentional control was replicated (r = -.33). The theta/beta ratio reflects, likely prefrontally mediated, attentional control, and should be a useful biomarker for the study of CPA and other anxiety-cognition interactions. PMID:24379166

  12. Properties and Modeling of GWAS when Complex Disease Risk Is Due to Non-Complementing, Deleterious Mutations in Genes of Large Effect

    PubMed Central

    Thornton, Kevin R.; Foran, Andrew J.; Long, Anthony D.

    2013-01-01

    Current genome-wide association studies (GWAS) have high power to detect intermediate frequency SNPs making modest contributions to complex disease, but they are underpowered to detect rare alleles of large effect (RALE). This has led to speculation that the bulk of variation for most complex diseases is due to RALE. One concern with existing models of RALE is that they do not make explicit assumptions about the evolution of a phenotype and its molecular basis. Rather, much of the existing literature relies on arbitrary mapping of phenotypes onto genotypes obtained either from standard population-genetic simulation tools or from non-genetic models. We introduce a novel simulation of a 100-kilobase gene region, based on the standard definition of a gene, in which mutations are unconditionally deleterious, are continuously arising, have partially recessive and non-complementing effects on phenotype (analogous to what is widely observed for most Mendelian disorders), and are interspersed with neutral markers that can be genotyped. Genes evolving according to this model exhibit a characteristic GWAS signature consisting of an excess of marginally significant markers. Existing tests for an excess burden of rare alleles in cases have low power while a simple new statistic has high power to identify disease genes evolving under our model. The structure of linkage disequilibrium between causative mutations and significantly associated markers under our model differs fundamentally from that seen when rare causative markers are assumed to be neutral. Rather than tagging single haplotypes bearing a large number of rare causative alleles, we find that significant SNPs in a GWAS tend to tag single causative mutations of small effect relative to other mutations in the same gene. Our results emphasize the importance of evaluating the power to detect associations under models that are genetically and evolutionarily motivated. PMID:23437004

  13. The Pattern and Distribution of Deleterious Mutations in Maize

    PubMed Central

    Mezmouk, Sofiane; Ross-Ibarra, Jeffrey

    2013-01-01

    Most nonsynonymous mutations are thought to be deleterious because of their effect on protein sequence and are expected to be removed or kept at low frequency by the action of natural selection. Nonetheless, the effect of positive selection on linked sites or drift in small or inbred populations may also impact the evolution of deleterious alleles. Despite their potential to affect complex trait phenotypes, deleterious alleles are difficult to study precisely because they are often at low frequency. Here, we made use of genome-wide genotyping data to characterize deleterious variants in a large panel of maize inbred lines. We show that, despite small effective population sizes and inbreeding, most putatively deleterious SNPs are indeed at low frequencies within individual genetic groups. We find that genes associated with a number of complex traits are enriched for deleterious variants. Together, these data are consistent with the dominance model of heterosis, in which complementation of numerous low-frequency, weak deleterious variants contribute to hybrid vigor. PMID:24281428

  14. The pattern and distribution of deleterious mutations in maize.

    PubMed

    Mezmouk, Sofiane; Ross-Ibarra, Jeffrey

    2014-01-01

    Most nonsynonymous mutations are thought to be deleterious because of their effect on protein sequence and are expected to be removed or kept at low frequency by the action of natural selection. Nonetheless, the effect of positive selection on linked sites or drift in small or inbred populations may also impact the evolution of deleterious alleles. Despite their potential to affect complex trait phenotypes, deleterious alleles are difficult to study precisely because they are often at low frequency. Here, we made use of genome-wide genotyping data to characterize deleterious variants in a large panel of maize inbred lines. We show that, despite small effective population sizes and inbreeding, most putatively deleterious SNPs are indeed at low frequencies within individual genetic groups. We find that genes associated with a number of complex traits are enriched for deleterious variants. Together, these data are consistent with the dominance model of heterosis, in which complementation of numerous low-frequency, weak deleterious variants contribute to hybrid vigor. PMID:24281428

  15. Marine reserves: Fish life history and ecological traits matter

    Microsoft Academic Search

    Joachim Claudet; Craig W. Osenberg; Paolo Domenici; F. Badalamenti; M. Milazzo; J. M. Falcón; I. Bertocci; L. Benedetti-Cecchi; J. A. García-Charton; R. Goñi; J. A. Borg; A. Forcada; G. A. de Lucia; Á Pérez-Ruzafa; P. Afonso; A. Brito; I. Guala; L. Le Diréach; P. Sanchez-Jerez; P. J. Somerfield; S. Planes

    2010-01-01

    Marine reserves are assumed to protect a wide range of species from deleterious effects stemming from exploitation. However, some species, due to their ecological characteristics, may not respond positively to protection. Very little is known about the effects of life history and ecological traits (e.g., mobility, growth, and habitat) on responses of fish species to marine reserves. Using 40 data

  16. Fructose supplementation worsens the deleterious effects of short-term high-fat feeding on hepatic steatosis and lipid metabolism in adult rats.

    PubMed

    Crescenzo, Raffaella; Bianco, Francesca; Coppola, Paola; Mazzoli, Arianna; Tussellino, Margherita; Carotenuto, Rosa; Liverini, Giovanna; Iossa, Susanna

    2014-09-01

    The purpose of the present study was to examine the short-term effect of high-fat or high-fat-high-fructose feeding on hepatic lipid metabolism and mitochondrial function in adult sedentary rats. Adult male rats were fed a high-fat or high-fat-high-fructose diet for 2 weeks. Body and liver composition, hepatic steatosis, plasma lipid profile and hepatic insulin sensitivity, together with whole-body and hepatic de novo lipogenesis, were assessed. Hepatic mitochondrial mass, functionality, oxidative stress and antioxidant defense were also measured. Rats fed the high-fat-high-fructose diet exhibited significantly higher plasma triglycerides, non-esterified fatty acids, insulin and indexes of hepatic insulin resistance compared with rats fed a low-fat or a high-fat diet. Hepatic triglycerides and ceramide, as well as the degree of steatosis and necrosis, were significantly higher, while liver p-Akt was significantly lower, in rats fed high-fat-high-fructose diet than in rats fed high-fat diet. A significant increase in non-protein respiratory quotient and hepatic fatty acid synthase and stearoyl CoA desaturase activity was found in rats fed the high-fat-high-fructose diet compared with those fed the high-fat diet. Significantly lower mitochondrial oxidative capacity but significantly higher oxidative stress was found in rats fed high-fat and high-fat-high-fructose diets compared with rats fed low-fat diet, while mitochondrial mass significantly increased only in rats fed high-fat-high-fructose diet. In conclusion, short-term consumption of a Western diet, rich in saturated fats and fructose, is more conducive to the development of liver steatosis and deleterious to glucose homeostasis than a high-fat diet. PMID:24972835

  17. Deleterious background selection with recombination

    SciTech Connect

    Hudson, R.R. [Univ. of California, Irvine, CA (United States); Kaplan, N.L. [National Institute of Environmental Health Sciences, Research Triangle Park, NC (United States)

    1995-12-01

    An analytic expression for the expected nucleotide diversity is obtained for a neutral locus in a region with deleterious mutation and recombination. Our analytic results are used to predict levels of variation for the entire third chromosome of Drosophila melanogaster. The predictions are consistent with the low levels of variation that have been observed at loci near the centromeres of the third chromosome of D. melanogaster. However, the low levels of variation observed near the tips of this chromosome are not predicted using currently available estimates of the deleterious mutation rate and of selection coefficients. If considerably smaller selection coefficients are assumed, the low observed levels of variation at the tips of the third chromosome are consistent with the background selection model. 33 refs., 4 figs., 1 tab.

  18. Ecological Correlates of Effective Foster Care

    ERIC Educational Resources Information Center

    Henderson, Daphne; Scannapieco, Maria

    2006-01-01

    Providing effective foster care is a major undertaking that continues to plague this country. The ultimate goal of substitute care is to provide child victims of maltreatment with a safe and nurturing home environment. The goal of this theory driven research project was to identify ecological factors correlated with effective non-kin family foster…

  19. An assessment of the ecological effects of acidic deposition

    Microsoft Academic Search

    John W. Huckabee; Jack S. Mattice; Louis F. Pitelka; Donald B. Porcella; Robert A. Goldstein

    1989-01-01

    Research on the ecological effects of acidic deposition has yielded information that currently permits a partial assessment of these effects. Establishing a relationship between deposition of acidity and ecological effects is a difficult, lengthy process; the complexity of ecosystems requires an integrated mechanism-level approach in order to obtain quantitative and predictive information. Known ecological effects of acidic deposition appear in

  20. OVERVIEW OF CLIMATE INFORMATION NEEDS FOR ECOLOGICAL EFFECTS MODELS

    EPA Science Inventory

    Atmospheric scientists engaged in climate change research require a basic understanding of how ecological effects models incorporate climate. This report provides an overview of existing ecological models that might be used to model climate change effects on vegetation. ome agric...

  1. DIRECTORY OF SHORT TERM TESTS FOR HEALTH AND ECOLOGICAL EFFECTS

    EPA Science Inventory

    The directory provides basic information on the short term tests for health and ecological effects being performed by various U.S. EPA Laboratories through the Office of Health and Ecological Effects. The test systems are cross-indexed....

  2. Deleterious GRM1 Mutations in Schizophrenia

    PubMed Central

    Vile, David; Chandler, David; Morar, Bharti; Cavanaugh, Juleen A.; Visscher, Peter M.; Jablensky, Assen; Pfleger, Kevin D. G.; Kalaydjieva, Luba

    2012-01-01

    We analysed a phenotypically well-characterised sample of 450 schziophrenia patients and 605 controls for rare non-synonymous single nucleotide polymorphisms (nsSNPs) in the GRM1 gene, their functional effects and family segregation. GRM1 encodes the metabotropic glutamate receptor 1 (mGluR1), whose documented role as a modulator of neuronal signalling and synaptic plasticity makes it a plausible schizophrenia candidate. In a recent study, this gene was shown to harbour a cluster of deleterious nsSNPs within a functionally important domain of the receptor, in patients with schizophrenia and bipolar disorder. Our Sanger sequencing of the GRM1 coding regions detected equal numbers of nsSNPs in cases and controls, however the two groups differed in terms of the potential effects of the variants on receptor function: 6/6 case-specific and only 1/6 control-specific nsSNPs were predicted to be deleterious. Our in-vitro experimental follow-up of the case-specific mutants showed that 4/6 led to significantly reduced inositol phosphate production, indicating impaired function of the major mGluR1signalling pathway; 1/6 had reduced cell membrane expression; inconclusive results were obtained in 1/6. Family segregation analysis indicated that these deleterious nsSNPs were inherited. Interestingly, four of the families were affected by multiple neuropsychiatric conditions, not limited to schizophrenia, and the mutations were detected in relatives with schizophrenia, depression and anxiety, drug and alcohol dependence, and epilepsy. Our findings suggest a possible mGluR1 contribution to diverse psychiatric conditions, supporting the modulatory role of the receptor in such conditions as proposed previously on the basis of in vitro experiments and animal studies. PMID:22448230

  3. Efficient Purging of Deleterious Mutations in Plants with Haploid Selfing

    PubMed Central

    Szövényi, Péter; Devos, Nicolas; Weston, David J.; Yang, Xiaohan; Hock, Zsófia; Shaw, Jonathan A.; Shimizu, Kentaro K.; McDaniel, Stuart F.; Wagner, Andreas

    2014-01-01

    In diploid organisms, selfing reduces the efficiency of selection in removing deleterious mutations from a population. This need not be the case for all organisms. Some plants, for example, undergo an extreme form of selfing known as intragametophytic selfing, which immediately exposes all recessive deleterious mutations in a parental genome to selective purging. Here, we ask how effectively deleterious mutations are removed from such plants. Specifically, we study the extent to which deleterious mutations accumulate in a predominantly selfing and a predominantly outcrossing pair of moss species, using genome-wide transcriptome data. We find that the selfing species purge significantly more nonsynonymous mutations, as well as a greater proportion of radical amino acid changes which alter physicochemical properties of amino acids. Moreover, their purging of deleterious mutation is especially strong in conserved regions of protein-coding genes. Our observations show that selfing need not impede but can even accelerate the removal of deleterious mutations, and do so on a genome-wide scale. PMID:24879432

  4. Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development in the Pacific Northwest

    E-print Network

    Wright, Dawn Jeannine

    Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development) develop an initial assessment of the potential impacting agents and ecological effects of wave energy are currently unknown. Benthic Habitat · Wave energy development can have a large

  5. ECOLOGICAL EFFECTS OF GENE FLOW.

    EPA Science Inventory

    The Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Government Performance Results Act (GPRA, goal number four for Safe Communities), constitute the statutory authority and strategic framework respectively, for Agency research on non-target effects of pestici...

  6. Ecology of estuaries: Anthropogenic effects

    SciTech Connect

    Kennish, M.J.

    1992-01-01

    Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated hydrocarbons; heavy metals; radionuclides) biological impacts; waste management; impacts of power plants; dredging and spoil disposal; case studies, primarily Chesapeake Bay. The book serves as a text and as a reference.

  7. Cascading ecological effects of eliminating fishery discards.

    PubMed

    Heath, Michael R; Cook, Robin M; Cameron, Angus I; Morris, David J; Speirs, Douglas C

    2014-01-01

    Discarding by fisheries is perceived as contrary to responsible harvesting. Legislation seeking to end the practice is being introduced in many jurisdictions. However, discarded fish are food for a range of scavenging species; so, ending discarding may have ecological consequences. Here we investigate the sensitivity of ecological effects to discarding policies using an ecosystem model of the North Sea--a region where 30-40% of trawled fish catch is currently discarded. We show that landing the entire catch while fishing as usual has conservation penalties for seabirds, marine mammals and seabed fauna, and no benefit to fish stocks. However, combining landing obligations with changes in fishing practices to limit the capture of unwanted fish results in trophic cascades that can benefit birds, mammals and most fish stocks. Our results highlight the importance of considering the broader ecosystem consequences of fishery management policy, since species interactions may dissipate or negate intended benefits. PMID:24820200

  8. Cascading ecological effects of eliminating fishery discards

    PubMed Central

    Heath, Michael R.; Cook, Robin M.; Cameron, Angus I.; Morris, David J.; Speirs, Douglas C.

    2014-01-01

    Discarding by fisheries is perceived as contrary to responsible harvesting. Legislation seeking to end the practice is being introduced in many jurisdictions. However, discarded fish are food for a range of scavenging species; so, ending discarding may have ecological consequences. Here we investigate the sensitivity of ecological effects to discarding policies using an ecosystem model of the North Sea—a region where 30–40% of trawled fish catch is currently discarded. We show that landing the entire catch while fishing as usual has conservation penalties for seabirds, marine mammals and seabed fauna, and no benefit to fish stocks. However, combining landing obligations with changes in fishing practices to limit the capture of unwanted fish results in trophic cascades that can benefit birds, mammals and most fish stocks. Our results highlight the importance of considering the broader ecosystem consequences of fishery management policy, since species interactions may dissipate or negate intended benefits. PMID:24820200

  9. EN-006 Ecology March 2001 Effects of Alternative Silvicultural Treatments

    E-print Network

    EN-006 Ecology March 2001 Effects of Alternative Silvicultural Treatments on the Diversity and protecting the ecological diversity of the forest. STUDY AREA The Roberts Creek Study Forest was established a previous forest. Extension Note Research Disciplines: Ecology ~ Geology ~ Geomorphology ~ Hydrology

  10. Deleterious mutation prediction in the secondary structure of RNAs

    PubMed Central

    Barash, Danny

    2003-01-01

    Methods for computationally predicting deleterious mutations have recently been investigated for proteins, mainly by probabilistic estimations in the context of genomic research for identifying single nucleotide polymorphisms that can potentially affect protein function. It has been demonstrated that in cases where a few homologs are available, ab initio predicted structures modeled by the Rosetta method can become useful for including structural information to improve the deleterious mutation prediction methods for proteins. In the field of RNAs where very few homologs are available at present, this analogy can serve as a precursor to investigate a deleterious mutation prediction approach that is based on RNA secondary structure. When attempting to develop models for the prediction of deleterious mutations in RNAs, useful structural information is available from folding algorithms that predict the secondary structure of RNAs, based on energy minimization. Detecting mutations with desired structural effects among all possible point mutations may then be valuable for the prediction of deleterious mutations that can be tested experimentally. Here, a method is introduced for the prediction of deleterious mutations in the secondary structure of RNAs. The mutation prediction method, based on subdivision of the initial structure into smaller substructures and construction of eigenvalue tables, is independent of the folding algorithms but relies on their success to predict the folding of small RNA structures. Application of this method to predict mutations that may cause structural rearrangements, thereby disrupting stable motifs, is given for prokaryotic transcription termination in the thiamin pyrophosphate and S-adenosyl-methionine induced riboswitches. Ribo switches are mRNA structures that have recently been found to regulate transcription termination or translation initiation in bacteria by conformation rearrangement in response to direct metabolite binding. Predicting deleterious mutations on riboswitches may succeed to systematically intervene in bacterial genetic control. PMID:14602917

  11. Potential Ecological Effects of Contaminants in the Exposed Par Pond Sediments

    SciTech Connect

    Paller, M.H. [Westinghouse Savannah River Company, AIKEN, SC (United States); Wike, L.D.

    1996-08-01

    Sediment and small mammal samples were collected from the exposed sediments of Par Pond in early 1995, shortly before the reservoir was refilled after a 4-year drawdown. Sampling was confined to elevations between 58 and 61 meters (190 and 200 feet) above mean sea level, which includes the sediments likely to be exposed if the Par Pond water level is permitted to fluctuate naturally. Both soil and small mammal samples were analyzed for a number of radionuclides and metals. Some of the soil samples were also analyzed for organic contaminants. The objective of the study was to determine if contaminant levels in the Par Pond sediments were high enough to cause deleterious ecological effects.

  12. Ecological effects on effective population size in an annual plant.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nutrient-limited soil can be a strong selective force on plant populations. In addition, ecological factors such as competitive interactions have been shown to have an effect on effective population size (Ne). Both Ne and selection are indicators of population evolutionary processes: selection can...

  13. Nonequilibrium model for estimating parameters of deleterious mutations

    NASA Astrophysics Data System (ADS)

    Gordo, Isabel; Dionisio, Francisco

    2005-03-01

    Deleterious mutations are of extreme evolutionary importance because, even though they are eliminated by natural selection, their continuous pressure creates a pool of variability in natural populations. They are of potential relevance for the existence of several features in evolution, such as sexual reproduction, and pose a risk to small asexual populations. Despite their extreme importance, the deleterious mutation rate and the effects of each mutation on fitness are poorly known quantities. Here we analyze a simple model that can be applied to simple experiments, in microorganisms, aiming at the quantification of these values.

  14. Exogenous antioxidants - Double-edged swords in cellular redox state: Health beneficial effects at physiologic doses versus deleterious effects at high doses:

    PubMed

    Bouayed, Jaouad; Bohn, Torsten

    2010-07-01

    The balance between oxidation and antioxidation is believed to be critical in maintaining healthy biological systems. Under physiological conditions, the human antioxidative defense system including e.g. superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione (GSH), and others, allows the elimination of excess reactive oxygen species (ROS) including, among others superoxide anions (O2•-), hydroxyl radicals (OH•), alkoxyl radicals (RO•), and peroxyradicals (ROO•). However, our endogenous antioxidant defense systems are incomplete without exogenous originating reducing compounds such as vitamin C, vitamin E, carotenoids and polyphenols, playing an essential role in many antioxidant mechanisms in living organisms. Therefore, there is continuous demand for exogenous antioxidants in order to prevent oxidative stress, representing a disequilibrium redox state in favor of oxidation. However, high doses of isolated compounds may be toxic, owing to prooxidative effects at high concentrations, or their potential to react with beneficial concentrations of ROS normally present at physiological conditions that are required for optimal cellular functioning. This review aims to examine the double-edged effects of dietary originating antioxidants with a focus on the most abundant compounds, especially polyphenols, vitamin C, vitamin E and carotenoids. Different approaches to enrich our body with exogenous antioxidants such as via synthetic antioxidants, diets rich in fruits and vegetables, and taking supplements will be reviewed, and experimental and epidemiological evidences discussed, highlighting that antioxidants at physiological doses are generally safe, exhibiting interesting health beneficial effects. PMID:20972369

  15. Ecological Effects of Wave Energy Development in the Pacific Northwest

    E-print Network

    Ecological Effects of Wave Energy Development in the Pacific Northwest A Scientific Workshop Technical Memorandum NMFS-F/SPO-92 #12;#12;Ecological Effects of Wave Energy Development in the Pacific......................................................................................................7 The Technology: Wave Energy Development on the West Coast Mirko Previsic, re vision consulting

  16. A Ruby in the Rubbish: Beneficial Mutations, Deleterious Mutations and the Evolution of Sex

    Microsoft Academic Search

    Joel R. Peck

    1994-01-01

    This study presents a mathematical model in which a single beneficial mutation arises in a very large population that is subject to frequent deleterious mutations. The results suggest that, if the population is sexual, then the deleterious mutations will have little effect on the ultimate fate of the beneficial mutation. However, if most offspring are produced asexually, then the probability

  17. Palytoxin and Analogs: Biological and Ecological Effects

    PubMed Central

    Ramos, Vítor; Vasconcelos, Vítor

    2010-01-01

    Palytoxin (PTX) is a potent marine toxin that was originally found in soft corals from tropical areas of the Pacific Ocean. Soon after, its occurrence was observed in numerous other marine organisms from the same ecological region. More recently, several analogs of PTX were discovered, remarkably all from species of the dinoflagellate genus Ostreopsis. Since these dinoflagellates are also found in other tropical and even in temperate regions, the formerly unsuspected broad distribution of these toxins was revealed. Toxicological studies with these compounds shows repeatedly low LD50 values in different mammals, revealing an acute toxic effect on several organs, as demonstrated by different routes of exposure. Bioassays tested for some marine invertebrates and evidences from environmental populations exposed to the toxins also give indications of the high impact that these compounds may have on natural food webs. The recognition of its wide distribution coupled with the poisoning effects that these toxins can have on animals and especially on humans have concerned the scientific community. In this paper, we review the current knowledge on the effects of PTX and its analogs on different organisms, exposing the impact that these toxins may have in coastal ecosystems. PMID:20714422

  18. SPS microwave health and ecological effects: Program area overview

    NASA Technical Reports Server (NTRS)

    Cahill, D. F.

    1980-01-01

    The potential microwave health and ecological effects due to the operations of the Satellite Power System are discussed. An outline of the research needed to insure public acceptance of the program is presented.

  19. EVOLUTIONARY AND ECOLOGICAL EFFECTS OF MULTIGENERATIONAL EXPOSURES TO ANTHROPOGENIC STRESSORS

    EPA Science Inventory

    Biological and ecological responses to stress are dictated by duration and frequency, as well as instantaneous magnitude. Conditional compensatory responses at the physiological and behavioral levels, referred to as ?acclimation', may mitigate effects on individuals experiencing ...

  20. Bilateral high-frequency stimulation of the subthalamic nucleus on attentional performance: transient deleterious effects and enhanced motivation in both intact and parkinsonian rats

    PubMed Central

    Baunez, Christelle; Christakou, Anastasia; Chudasama, Yogita; Forni, Claude; Robbins, Trevor W.

    2007-01-01

    It is now well established that subthalamic nucleus high-frequency stimulation (STN HFS) alleviates motor problems in Parkinson's disease. However, its efficacy for cognitive function remains a matter of debate. The aim of this study was to assess the effects of STN HFS in rats performing a visual attentional task. Bilateral STN HFS was applied in intact and in bilaterally dopamine (DA)-depleted rats. In all animals, STN HFS had a transient debilitating effect on all the variables measured in the task. In DA-depleted rats, STN HFS did not alleviate the deficits induced by the DA lesion such as omissions and latency to make correct responses, but induced perseverative approaches to the food magazine, an indicator of enhanced motivation. In sham-operated controls, STN HFS significantly reduced accuracy and induced perseverative behaviour, mimicking partially the effects of bilateral STN lesions in the same task. These results are in line with the hypothesis that STN HFS only partially mimics inactivation of STN produced by lesioning and confirm the motivational exacerbation induced by STN inactivation. PMID:17331214

  1. Bilateral high-frequency stimulation of the subthalamic nucleus on attentional performance: transient deleterious effects and enhanced motivation in both intact and parkinsonian rats.

    PubMed

    Baunez, Christelle; Christakou, Anastasia; Chudasama, Yogita; Forni, Claude; Robbins, Trevor W

    2007-02-01

    It is now well established that subthalamic nucleus high-frequency stimulation (STN HFS) alleviates motor problems in Parkinson's disease. However, its efficacy for cognitive function remains a matter of debate. The aim of this study was to assess the effects of STN HFS in rats performing a visual attentional task. Bilateral STN HFS was applied in intact and in bilaterally dopamine (DA)-depleted rats. In all animals, STN HFS had a transient debilitating effect on all the variables measured in the task. In DA-depleted rats, STN HFS did not alleviate the deficits induced by the DA lesion such as omissions and latency to make correct responses, but induced perseverative approaches to the food magazine, an indicator of enhanced motivation. In sham-operated controls, STN HFS significantly reduced accuracy and induced perseverative behaviour, mimicking partially the effects of bilateral STN lesions in the same task. These results are in line with the hypothesis that STN HFS only partially mimics inactivation of STN produced by lesioning and confirm the motivational exacerbation induced by STN inactivation. PMID:17331214

  2. The role of the interactome in the maintenance of deleterious variability in human populations.

    PubMed

    Garcia-Alonso, Luz; Jiménez-Almazán, Jorge; Carbonell-Caballero, Jose; Vela-Boza, Alicia; Santoyo-López, Javier; Antiñolo, Guillermo; Dopazo, Joaquin

    2014-01-01

    Recent genomic projects have revealed the existence of an unexpectedly large amount of deleterious variability in the human genome. Several hypotheses have been proposed to explain such an apparently high mutational load. However, the mechanisms by which deleterious mutations in some genes cause a pathological effect but are apparently innocuous in other genes remain largely unknown. This study searched for deleterious variants in the 1,000 genomes populations, as well as in a newly sequenced population of 252 healthy Spanish individuals. In addition, variants causative of monogenic diseases and somatic variants from 41 chronic lymphocytic leukaemia patients were analysed. The deleterious variants found were analysed in the context of the interactome to understand the role of network topology in the maintenance of the observed mutational load. Our results suggest that one of the mechanisms whereby the effect of these deleterious variants on the phenotype is suppressed could be related to the configuration of the protein interaction network. Most of the deleterious variants observed in healthy individuals are concentrated in peripheral regions of the interactome, in combinations that preserve their connectivity, and have a marginal effect on interactome integrity. On the contrary, likely pathogenic cancer somatic deleterious variants tend to occur in internal regions of the interactome, often with associated structural consequences. Finally, variants causative of monogenic diseases seem to occupy an intermediate position. Our observations suggest that the real pathological potential of a variant might be more a systems property rather than an intrinsic property of individual proteins. PMID:25261458

  3. The role of the interactome in the maintenance of deleterious variability in human populations

    PubMed Central

    Garcia-Alonso, Luz; Jiménez-Almazán, Jorge; Carbonell-Caballero, Jose; Vela-Boza, Alicia; Santoyo-López, Javier; Antiñolo, Guillermo; Dopazo, Joaquin

    2014-01-01

    Recent genomic projects have revealed the existence of an unexpectedly large amount of deleterious variability in the human genome. Several hypotheses have been proposed to explain such an apparently high mutational load. However, the mechanisms by which deleterious mutations in some genes cause a pathological effect but are apparently innocuous in other genes remain largely unknown. This study searched for deleterious variants in the 1,000 genomes populations, as well as in a newly sequenced population of 252 healthy Spanish individuals. In addition, variants causative of monogenic diseases and somatic variants from 41 chronic lymphocytic leukaemia patients were analysed. The deleterious variants found were analysed in the context of the interactome to understand the role of network topology in the maintenance of the observed mutational load. Our results suggest that one of the mechanisms whereby the effect of these deleterious variants on the phenotype is suppressed could be related to the configuration of the protein interaction network. Most of the deleterious variants observed in healthy individuals are concentrated in peripheral regions of the interactome, in combinations that preserve their connectivity, and have a marginal effect on interactome integrity. On the contrary, likely pathogenic cancer somatic deleterious variants tend to occur in internal regions of the interactome, often with associated structural consequences. Finally, variants causative of monogenic diseases seem to occupy an intermediate position. Our observations suggest that the real pathological potential of a variant might be more a systems property rather than an intrinsic property of individual proteins. PMID:25261458

  4. Brain tissue oxidative damage as a possible mechanism for the deleterious effect of a chronic high dose of estradiol on learning and memory in ovariectomized rats.

    PubMed

    Khodabandehloo, Fatimeh; Hosseini, Mahmoud; Rajaei, Ziba; Soukhtanloo, Mohammad; Farrokhi, Esmaeil; Rezaeipour, Mohsen

    2013-05-01

    In addition to antioxidative effects, estrogens also exert pro-oxidative actions. The effect of chronic administration of a high dose of estradiol valerate on Morris water maze tasks and brain tissues oxidative damage was investigated. The Sham-Est and OVX-Est groups were treated with estradiol valerate (4 mg/kg) for 12 weeks. Escape latency and traveled path in the Sham-Est and OVX-Est groups were significantly higher than in the Sham and OVX groups (p<0.01 and p<0.001). In the probe trial, the animals of the Sham-Est and OVX-Est groups spent lower time in Q1 compared to Sham and OVX groups (p<0.05 and p<0.001). In Sham-Est and OVX-Est groups, the brain tissue total thiol concentration was significantly lower, and malondialdehyde (MDA) concentrations were higher than in the Sham and OVX groups (p<0.05 and p<0.001). It is concluded that administration of high exogenous levels of estradiol impairs performance and enhances oxidative stress. PMID:23689409

  5. Indole-3-carbinol attenuates the deleterious gestational effects of bisphenol A exposure on the prostate gland of male F1 rats.

    PubMed

    Brandt, Joyce Zalotti; Silveira, Lívia Teresa R; Grassi, Tony Fernando; Anselmo-Franci, Janete A; Fávaro, Wagner José; Felisbino, Sérgio Luis; Barbisan, Luis Fernando; Scarano, Wellerson Rodrigo

    2014-01-01

    Bisphenol A (BPA) is a chemical that has been investigated for it potential to cause prostate diseases. In this study, pregnant Sprague-Dawley rats were treated with 25 or 250 ?g/kg BPA from gestational day (GD) 10 to GD21 with or without concurrent indole-3-carbinol (I3C) feeding. I3C is a phytochemical, and it affords chemoprotection against many types of neoplasia. Male F1 rats from different litters were euthanized on post-natal day (PND) 21 and PND180. BPA-treated groups showed a significant increase in histopathological lesions, but I3C feeding reversed many of these changes, mainly at PND180. Maternal I3C feeding increased prostate epithelial apoptosis in the BPA-treated groups and across age groups. Furthermore, I3C induced partial normalization of the prostate histoarchitecture. The results pointed to a protective effect of maternal I3C feeding during pregnancy in the BPA-exposed male offspring, thereby indicating reduction in the harmful effects of gestational BPA imprinting on the prostate. PMID:24257414

  6. Ecological and Evolutionary Effects of Stickleback on Community Structure

    PubMed Central

    Des Roches, Simone; Shurin, Jonathan B.; Schluter, Dolph; Harmon, Luke J.

    2013-01-01

    Species’ ecology and evolution can have strong effects on communities. Both may change concurrently when species colonize a new ecosystem. We know little, however, about the combined effects of ecological and evolutionary change on community structure. We simultaneously examined the effects of top-predator ecology and evolution on freshwater community parameters using recently evolved generalist and specialist ecotypes of three-spine stickleback (Gasterosteus aculeatus). We used a mesocosm experiment to directly examine the effects of ecological (fish presence and density) and evolutionary (phenotypic diversity and specialization) factors on community structure at lower trophic levels. We evaluated zooplankton biomass and composition, periphyton and phytoplankton chlorophyll-a concentration, and net primary production among treatments containing different densities and diversities of stickleback. Our results showed that both ecological and evolutionary differences in the top-predator affect different aspects of community structure and composition. Community structure, specifically the abundance of organisms at each trophic level, was affected by stickleback presence and density, whereas composition of zooplankton was influenced by stickleback diversity and specialization. Primary productivity, in terms of chlorophyll-a concentration and net primary production was affected by ecological but not evolutionary factors. Our results stress the importance of concurrently evaluating both changes in density and phenotypic diversity on the structure and composition of communities. PMID:23573203

  7. Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African Buffalo: a plausible new mechanism for a high frequency anomaly.

    PubMed

    van Hooft, Pim; Greyling, Ben J; Getz, Wayne M; van Helden, Paul D; Zwaan, Bas J; Bastos, Armanda D S

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important implications for our understanding not only of the evolutionary and ecological dynamics of sex-ratio distorters and suppressors, but also of the functioning of deleterious and sexually-antagonistic alleles, and their impact on population viability. PMID:25372610

  8. Positive Selection of Deleterious Alleles through Interaction with a Sex-Ratio Suppressor Gene in African Buffalo: A Plausible New Mechanism for a High Frequency Anomaly

    PubMed Central

    van Hooft, Pim; Greyling, Ben J.; Getz, Wayne M.; van Helden, Paul D.; Zwaan, Bas J.; Bastos, Armanda D. S.

    2014-01-01

    Although generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this body-condition-associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important implications for our understanding not only of the evolutionary and ecological dynamics of sex-ratio distorters and suppressors, but also of the functioning of deleterious and sexually-antagonistic alleles, and their impact on population viability. PMID:25372610

  9. Ecological Effects of the War in Vietnam

    ERIC Educational Resources Information Center

    Orians, Gordon H.; Pfeiffer, E. W.

    1970-01-01

    Research report on the severe ecological consequences of the defoliation program by American military forces in Vietnam. A significant fraction of mature trees in most forests are killed by single application of herbicides and almost completely killed by repeated sprayings. AAAS is urged to set up an international research program on the…

  10. Ecological effects of the North Atlantic Oscillation

    Microsoft Academic Search

    Geir Ottersen; Benjamin Planque; Andrea Belgrano; Eric Post; Philip C. Reid; Nils C. Stenseth

    2001-01-01

    Climatic oscillations as reflected in atmospheric modes such as the North Atlantic Oscillation (NAO) may be seen as a proxy for regulating forces in aquatic and terrestrial ecosystems. Our review highlights the variety of climate processes related to the NAO and the diversity in the type of ecological responses that different biological groups can display. Available evidence suggests that the

  11. [Effect of ecological factors on citrus fruit quality].

    PubMed

    Bao, Jiangfeng; Xia, Renxue; Peng, Shu'ang

    2004-08-01

    This paper summarized the research advance on the physiological foundation of citrus fruit's major quality factors such as color formation and organic acid and sugar accumulation, and analyzed the effects of main ecological factors such as temperature, sunshine, water, soil, terrain and landforms on them. The existing problems and the research prospects of citrus ecology were expounded, and a useful proposal on the quality sub-distribution of citrus in China was put forward. PMID:15574012

  12. Phytoremediation Potential of Maná-Cubiu (Solanum sessiliflorum Dunal) for the Deleterious Effects of Methylmercury on the Reproductive System of Rats

    PubMed Central

    Frenedoso da Silva, Raquel; Missassi, Gabriela; dos Santos Borges, Cibele; Silva de Paula, Eloísa; Hornos Carneiro, Maria Fernanda; Barbosa Junior, Fernando; De Grava Kempinas, Wilma

    2014-01-01

    Methylmercury, organic form of mercury, can increase the number of abnormal sperm and decrease sperm concentration and testosterone levels possibly due to the damage caused by reactive species to germ and Leydig cells. Maná-cubiu (Solanum sessiliflorum Dunal) is a native fruit from Amazon rich in iron, zinc, niacin, pectin, and citric acid, used in foods, beverages, and medicinal purposes, since it has been useful for treatment of various diseases caused by oxidative stress or nutritional deficiency. Therefore, this study evaluated the phytoremediation potential of this fruit on damages caused by exposure to MeHg on sperm quantity and quality and the histological aspect of the testis and epididymis. Wistar male rats (n = 20) were randomly allocated into four groups: Control group (received distilled water), MeHg group (140??g/Kg), Solanum group (1% of fruit Maná-cubiu on chow), and Solanum plus MeHg group (same treatment as MeHg and Solanum group). The organs were weighted, histopathology; sperm morphology and counts were obtained. The results showed reduction in body weight gain, testis weights, reduced sperm production, and increased histopathological abnormalities in the MeHg-treated group. However, treatment with Solanum plus MeHg revealed a protective effect of this fruit on damages caused by MeHg. PMID:24772420

  13. Deleterious effect of the Qo inhibitor compound resistance-conferring mutation G143A in the intron-containing cytochrome b gene and mechanisms for bypassing it.

    PubMed

    Vallières, Cindy; Trouillard, Martin; Dujardin, Geneviève; Meunier, Brigitte

    2011-03-01

    The mutation G143A in the inhibitor binding site of cytochrome b confers a high level of resistance to fungicides targeting the bc(1) complex. The mutation, reported in many plant-pathogenic fungi, has not evolved in fungi that harbor an intron immediately after the codon for G143 in the cytochrome b gene, intron bi2. Using Saccharomyces cerevisiae as a model organism, we show here that a codon change from GGT to GCT, which replaces glycine 143 with alanine, hinders the splicing of bi2 by altering the exon/intron structure needed for efficient intron excision. This lowers the levels of cytochrome b and respiratory growth. We then investigated possible bypass mechanisms that would restore the respiratory fitness of a resistant mutant. Secondary mutations in the mitochondrial genome were found, including a point mutation in bi2 restoring the correct exon/intron structure and the deletion of intron bi2. We also found that overexpression of nuclear genes MRS2 and MRS3, encoding mitochondrial metal ion carriers, partially restores the respiratory growth of the G143A mutant. Interestingly, the MRS3 gene from the plant-pathogenic fungus Botrytis cinerea, overexpressed in an S. cerevisiae G143A mutant, had a similar compensatory effect. These bypass mechanisms identified in yeast could potentially arise in pathogenic fungi. PMID:21278281

  14. Environmental concentrations of irgarol, diuron and S-metolachlor induce deleterious effects on gametes and embryos of the Pacific oyster, Crassostrea gigas.

    PubMed

    Mai, Huong; Morin, Bénédicte; Pardon, Patrick; Gonzalez, Patrice; Budzinski, Hélène; Cachot, Jérôme

    2013-08-01

    Irgarol and diuron are the most representative "organic booster biocides" that replace organotin compounds in antifouling paints, and metolachlor is one of the most extensively used chloroacetamide herbicides in agriculture. The toxicity of S-metolachlor, irgarol and diuron was evaluated in Pacific oyster (Crassostrea gigas) gametes or embryos exposed to concentrations of pesticides ranging from 0.1× to 1000×, with 1× corresponding to environmental concentrations of the three studied pesticides in Arcachon Bay (France). Exposures were performed on (1) spermatozoa alone (2) oocytes alone and (3) both spermatozoa and oocytes, and adverse effects on fertilization success and offspring development were recorded. The results showed that the fertilizing capacity of spermatozoa was significantly affected after gamete exposure to pesticide concentrations as low as 1× of irgarol and diuron and 10× of metolachlor. The offspring obtained from pesticide-exposed spermatozoa displayed a dose-dependent increase in developmental abnormalities. In contrast, treating oocytes with pesticide concentrations up to 10× did not alter fertilization rate and offspring quality. However, a significant decline in fertilization success and increase in abnormal D-larvae prevalence were observed at higher concentrations 10× (0.1 ?g L(-1)) for S-metolachlor and 100× for irgarol (1.0 ?g L(-1)) and diuron (4.0 ?g L(-1)). Irgarol, diuron and S-metolachlor also induced a dose-dependent increase in abnormal D-larvae prevalence when freshly fertilized embryos were treated with pesticide concentrations as low as concentration of 1× (0.01 ?g L(-1) for irgarol or S-metolachlor, and 0.04 ?g L(-1) for diuron). The two bioassays on C. gigas spermatozoa and embryos displayed similar sensitivities to the studied pesticides while oocytes were less sensitive. Diuron, irgarol and S-metolachlor induced spermiotoxicity and embryotoxicity at environmentally relevant concentrations and therefore might be a threat to oyster recruitment in coastal areas facing chronic inputs of pesticides. PMID:23727205

  15. On the accumulation of deleterious mutations during range expansions.

    PubMed

    Peischl, S; Dupanloup, I; Kirkpatrick, M; Excoffier, L

    2013-12-01

    We investigate the effect of spatial range expansions on the evolution of fitness when beneficial and deleterious mutations cosegregate. We perform individual-based simulations of 1D and 2D range expansions and complement them with analytical approximations for the evolution of mean fitness at the edge of the expansion. We find that deleterious mutations accumulate steadily on the wave front during range expansions, thus creating an expansion load. Reduced fitness due to the expansion load is not restricted to the wave front, but occurs over a large proportion of newly colonized habitats. The expansion load can persist and represent a major fraction of the total mutation load for thousands of generations after the expansion. The phenomenon of expansion load may explain growing evidence that populations that have recently expanded, including humans, show an excess of deleterious mutations. To test the predictions of our model, we analyse functional genetic diversity in humans and find patterns that are consistent with our model. PMID:24102784

  16. Ecological traps in changing environments: Ecological and evolutionary consequences of a behaviourally mediated Allee effect

    Microsoft Academic Search

    Hanna Kokko; William J. Sutherland

    Species usually have to use indirect cues when assessing habitat quality. This means that it is possible for humans to alter habitats in a way that causes a discrepancy between the cues and the true quality of different habitats. This phenomenon is called an 'ecological trap'. Here we show that the trap may lead to a behaviourally mediated Allee effect,

  17. EPA'S ECOLOGICAL EFFECTS BRANCH: PLANNING FOR AN UNCERTAIN FUTURE

    EPA Science Inventory

    The seminar will address two topics: 1) a brief overview of Dr. Hammer?s professional experiences that preceded his appointment with the Environmental Protection Agency; and 2) a summary of current projects being planned by the Ecological Effects Branch of the Environmental Prote...

  18. Some Sociological and Ecological Effects . of the Conservation Reserve Program

    E-print Network

    . This study was supportedby the FederalAid to Wild- life Restoration Fund. Pmject W-75-R.Study Number 7537Some Sociological and Ecological Effects . of the Conservation Reserve Program in the Northern Cooperative FIsh &Wildlife Research Unit South DakDtaState UniversityJ Brooldngs,SD Abstract.-TheConservation

  19. REVIEWS AND SYNTHESES Ecology of invasive mosquitoes: effects on resident

    E-print Network

    Juliano, Steven A.

    *Correspondence: E-mail: sajulian@ilstu.edu Abstract Investigations of biological invasions focus on patterns: 558­574 I N T R O DU C T I O N Invasion biology focuses on patterns and processes relatedREVIEWS AND SYNTHESES Ecology of invasive mosquitoes: effects on resident species and on human

  20. The ecological effects of biological invasions on birds

    Microsoft Academic Search

    Gan Xiaojing; Bo Li; Jiakuan Chen; Zhijun Ma

    2007-01-01

    Biological invasion is recognized as one of the greatest threats to the global biodiversity because invasive exotic species not only alter the local environments but also have serious ecological effects on native species. Birds are positioned at high trophic level within the food web in the ecosystem, and thus any changes within the system can affect the birds in one

  1. Effects of aging on microbial ecology in swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Emissions and availability of nutrients from manure depends on activities of resident microorganisms; however, the effects of diet, animal genetics or treatments on the microbial ecology of pig manure is largely unknown. Stainless steel tanks with total manure capacity of 900 L were designed to all...

  2. Status and Ecological Effects of the World's Largest Carnivores

    E-print Network

    Wilmers, Chris

    Status and Ecological Effects of the World's Largest Carnivores William J. Ripple,* James A. Estes and large body size, these carnivores often require large prey and expansive habitats. These food, in addition to human intolerance, renders them vulnerable to extinction. Large carnivores face enormous

  3. ECOLOGICAL EFFECTS OF NITROGEN DEPOSITION IN THE WESTERN UNITED STATES

    EPA Science Inventory

    Article synthesizes existing studies (biological, ecological, biogeochemical) on the effects of nitrogen deposition to aquatic and terrestrial ecosystems in the western United States. In the western U.S, vast acreages of land are exposed to low levels of atmospheric deposition, w...

  4. Disease ecology. Ecological and evolutionary effects of fragmentation on infectious disease dynamics.

    PubMed

    Jousimo, Jussi; Tack, Ayco J M; Ovaskainen, Otso; Mononen, Tommi; Susi, Hanna; Tollenaere, Charlotte; Laine, Anna-Liisa

    2014-06-13

    Ecological theory predicts that disease incidence increases with increasing density of host networks, yet evolutionary theory suggests that host resistance increases accordingly. To test the combined effects of ecological and evolutionary forces on host-pathogen systems, we analyzed the spatiotemporal dynamics of a plant (Plantago lanceolata)-fungal pathogen (Podosphaera plantaginis)relationship for 12 years in over 4000 host populations. Disease prevalence at the metapopulation level was low, with high annual pathogen extinction rates balanced by frequent (re-)colonizations. Highly connected host populations experienced less pathogen colonization and higher pathogen extinction rates than expected; a laboratory assay confirmed that this phenomenon was caused by higher levels of disease resistance in highly connected host populations. PMID:24926021

  5. Characteristics of neutral and deleterious protein-coding variation among individuals and populations.

    PubMed

    Fu, Wenqing; Gittelman, Rachel M; Bamshad, Michael J; Akey, Joshua M

    2014-10-01

    Whole-genome and exome data sets continue to be produced at a frenetic pace, resulting in massively large catalogs of human genomic variation. However, a clear picture of the characteristics and patterns of neutral and deleterious variation within and between populations has yet to emerge, given that recent large-scale sequencing studies have often emphasized different aspects of the data and sometimes appear to have conflicting conclusions. Here, we comprehensively studied characteristics of protein-coding variation in high-coverage exome sequence data from 6,515 European American (EA) and African American (AA) individuals. We developed an unbiased approach to identify putatively deleterious variants and investigated patterns of neutral and deleterious single-nucleotide variants and alleles between individuals and populations. We show that there are substantial differences in the composition of genotypes between EA and AA populations and that small but statistically significant differences exist in the average number of deleterious alleles carried by EA and AA individuals. Furthermore, we performed extensive simulations to delineate the temporal dynamics of deleterious alleles for a broad range of demographic models and use these data to inform the interpretation of empirical patterns of deleterious variation. Finally, we illustrate that the effects of demographic perturbations, such as bottlenecks and expansions, often manifest in opposing patterns of neutral and deleterious variation depending on whether the focus is on populations or individuals. Our results clarify seemingly disparate empirical characteristics of protein-coding variation and provide substantial insights into how natural selection and demographic history have patterned neutral and deleterious variation within and between populations. PMID:25279984

  6. Characteristics of Neutral and Deleterious Protein-Coding Variation among Individuals and Populations

    PubMed Central

    Fu, Wenqing; Gittelman, Rachel M.; Bamshad, Michael J.; Akey, Joshua M.

    2014-01-01

    Whole-genome and exome data sets continue to be produced at a frenetic pace, resulting in massively large catalogs of human genomic variation. However, a clear picture of the characteristics and patterns of neutral and deleterious variation within and between populations has yet to emerge, given that recent large-scale sequencing studies have often emphasized different aspects of the data and sometimes appear to have conflicting conclusions. Here, we comprehensively studied characteristics of protein-coding variation in high-coverage exome sequence data from 6,515 European American (EA) and African American (AA) individuals. We developed an unbiased approach to identify putatively deleterious variants and investigated patterns of neutral and deleterious single-nucleotide variants and alleles between individuals and populations. We show that there are substantial differences in the composition of genotypes between EA and AA populations and that small but statistically significant differences exist in the average number of deleterious alleles carried by EA and AA individuals. Furthermore, we performed extensive simulations to delineate the temporal dynamics of deleterious alleles for a broad range of demographic models and use these data to inform the interpretation of empirical patterns of deleterious variation. Finally, we illustrate that the effects of demographic perturbations, such as bottlenecks and expansions, often manifest in opposing patterns of neutral and deleterious variation depending on whether the focus is on populations or individuals. Our results clarify seemingly disparate empirical characteristics of protein-coding variation and provide substantial insights into how natural selection and demographic history have patterned neutral and deleterious variation within and between populations. PMID:25279984

  7. Quantifying genetic diversity under a broad spectrum of deleterious mutations

    NASA Astrophysics Data System (ADS)

    Good, Benjamin; Desai, Michael

    2013-03-01

    Recent studies have shown that selection against deleterious mutations may play a major role in shaping observed patterns of sequence variation in natural populations. However, our understanding of these patterns remains limited, since selection creates correlations along the genome that are difficult to disentangle from each other. Previous theoretical work has focused on the qualitative effects of selection on sequence diversity, using simplified models in which all selected mutations have the same fitness cost. Yet is known that deleterious mutations follow a wide distribution in most organisms, so it is necessary to extend our theoretical predictions to this more general case before we can make quantitative connections with existing data. The evolutionary dynamics of this regime are complicated: extant mutant lineages represent large, correlated fluctuations away from the background expectation, which hinders efforts to apply existing methods based on deterministic or ``mean-field'' approximations. Here, we will describe recent progress towards this goal, which is based on a ``coarse-graining'' of the underlying distribution of fitnesses in the population.

  8. Sex-chromosome turnovers induced by deleterious mutation load.

    PubMed

    Blaser, Olivier; Grossen, Christine; Neuenschwander, Samuel; Perrin, Nicolas

    2013-03-01

    In sharp contrast with mammals and birds, many cold-blooded vertebrates present homomorphic sex chromosomes. Empirical evidence supports a role for frequent turnovers, which replace nonrecombining sex chromosomes before they have time to decay. Three main mechanisms have been proposed for such turnovers, relying either on neutral processes, sex-ratio selection, or intrinsic benefits of the new sex-determining genes (due, e.g., to linkage with sexually antagonistic mutations). Here, we suggest an additional mechanism, arising from the load of deleterious mutations that accumulate on nonrecombining sex chromosomes. In the absence of dosage compensation, this load should progressively lower survival rate in the heterogametic sex. Turnovers should occur when this cost outweighs the benefits gained from any sexually antagonistic genes carried by the nonrecombining sex chromosome. We use individual-based simulations of a Muller's ratchet process to test this prediction, and investigate how the relevant parameters (effective population size, strength and dominance of deleterious mutations, size of nonrecombining segment, and strength of sexually antagonistic selection) are expected to affect the rate of turnovers. PMID:23461315

  9. Ecological Effects of Nitrogen Deposition in the Western United States

    NSDL National Science Digital Library

    MARK E. FENN, JILL S. BARON, EDITH B. ALLEN, HEATHER M. RUETH, KOREN R. NYDICK, LINDA GEISER, WILLIAM D. BOWMAN, JAMES O. SICKMAN, THOMAS MEIXNER, DALE W. JOHNSON, and PETER NEITLICH (; )

    2003-04-01

    This peer-reviewed article from BioScience is about nitrogen deposition in the western United States. In the western United States vast acreages of land are exposed to low levels of atmospheric nitrogen (N) deposition, with interspersed hotspots of elevated N deposition downwind of large, expanding metropolitan centers or large agricultural operations. Biological response studies in western North America demonstrate that some aquatic and terrestrial plant and microbial communities are significantly altered by N deposition. Greater plant productivity is counterbalanced by biotic community changes and deleterious effects on sensitive organisms (lichens and phytoplankton) that respond to low inputs of N (3 to 8 kilograms N per hectare per year). Streamwater nitrate concentrations are elevated in high-elevation catchments in Colorado and are unusually high in southern California and in some chaparral catchments in the southwestern Sierra Nevada. Chronic N deposition in the West is implicated in increased fire frequency in some areas and habitat alteration for threatened species. Between hotspots, N deposition is too low to cause noticeable effects or has not been studied.

  10. A METHOD TO INCORPORATE ECOLOGY INTO RESIDENCE TIME OF CHEMICALS IN EMBAYMENTS: LOCAL EFFECT TIME

    EPA Science Inventory

    Residence times are classically defined by the physical and chemical aspects of water bodies rather than by their ecological implications. Therefore, a more clear and direct connection between the residence times and ecological effects is necessary to quantitatively relate these ...

  11. ASTER: AN INTEGRATION OF THE AQUIRE DATABASE AND THE QSAR SYSTEM FOR USE IN ECOLOGICAL RISK ASSESSMENT

    EPA Science Inventory

    Ecological risk assessments are used by the U.S. Environmental Protection Agency (USEPA) and other governmental agencies to assist in determining the probability and magnitude of deleterious effects of hazardous chemicals on plants and animals. hese assessments are important step...

  12. ASTER: AN INTEGRATION OF THE AQUIRE DATABASE AND THE QSAR SYSTEM FOR USE IN ECOLOGICAL RISK ASSESSMENTS

    EPA Science Inventory

    Ecological risk assessments are used by the U.S. Environmental Protection Agency (USEPA) and other governmental agencies to assist in determining the probability and magnitude of deleterious effects of hazardous chemicals on plants and animals. hese assessments are important step...

  13. Oil spill studies: review of ecological effects

    SciTech Connect

    Teal, J.M.; Howarth, R.W.

    1984-01-01

    The authors studied oil spills that have occurred since the National Academy of Sciences 1975 report, ''Petroleum in the Marine Environment'' or that occurred prior to that report but about which significant new information has since been acquired. The spills studied were from the barge Florida, and tankers Arrow, Argo Merchant, Amoco Cadiz, and Tsesis and blowouts from the Bravo and Ixtoc I platforms. These ''best'' studies yield only limited insight into effects because they lack controls and have a high degree of natural variability. The Tsesis, Florida, and Amoco Cadiz cases are exceptional since they occurred in areas of ongoing research programs and had nearby areas suitable for controls. Oil spills have produced measureable effects on ecosystems that have not been readily predictable from laboratory studies on isolated organisms. However, ecosystem-level interactions are poorly understood even without the complications resulting from effects of pollution. These generalizations emerge: oil regularly reaches sediments after a spill; oil in anoxic sediments is persistent; oil regularly contaminates zooplankton and benthic invertebrates; fish are also contaminated, but to a lesser extent; oil contamination decreases the abundance and diversity of benthic communities.

  14. Downstream ecological effects of dams: A geomorphic perspective

    SciTech Connect

    Ligon, F.K. [EA Engineering, Science, and Technology, Lafayette, CA (United States); Dietrich, W.E. [Univ. of California, Berkeley, CA (United States); Trush, W.J. [Humboldt State Univ., Arcata, CA (United States)

    1995-03-01

    The damming of a river changes the flow of water, sediment, nutrients, energy, and biota, interrupting and altering most of a river`s ecological processes. This article discusses the importance of geomorphological analysis in river conservation and management. To illustrate how subtle geomorphological adjustments may profoundly influence the ecological relationships downstream from dames, three case studies are presented. Then a geomorphically based approach for assessing and possibly mitigating some of the environmental effects of dams by tailoring dam designed and operation is outlined. The cases are as follows: channel simplification and salmon decline on the McKenzie River in Oregon; Channel incision and reduced floodplain inundation on the Oconee river in Georgia; Increased stability of a braided river in New Zealand`s south island. 41 refs., 10 figs., 1 tab.

  15. Ecological and socioeconomic effects of China's policies for ecosystem services

    PubMed Central

    Liu, Jianguo; Li, Shuxin; Ouyang, Zhiyun; Tam, Christine; Chen, Xiaodong

    2008-01-01

    To address devastating environmental crises and to improve human well-being, China has been implementing a number of national policies on payments for ecosystem services. Two of them, the Natural Forest Conservation Program (NFCP) and the Grain to Green Program (GTGP), are among the biggest programs in the world because of their ambitious goals, massive scales, huge payments, and potentially enormous impacts. The NFCP conserves natural forests through logging bans and afforestation with incentives to forest enterprises, whereas the GTGP converts cropland on steep slopes to forest and grassland by providing farmers with grain and cash subsidies. Overall ecological effects are beneficial, and socioeconomic effects are mostly positive. Whereas there are time lags in ecological effects, socioeconomic effects are more immediate. Both the NFCP and the GTGP also have global implications because they increase vegetative cover, enhance carbon sequestration, and reduce dust to other countries by controlling soil erosion. The future impacts of these programs may be even bigger. Extended payments for the GTGP have recently been approved by the central government for up to 8 years. The NFCP is likely to follow suit and receive renewed payments. To make these programs more effective, we recommend systematic planning, diversified funding, effective compensation, integrated research, and comprehensive monitoring. Effective implementation of these programs can also provide important experiences and lessons for other ecosystem service payment programs in China and many other parts of the world. PMID:18621700

  16. Visual search in ecological and non-ecological displays: evidence for a non-monotonic effect of complexity on performance.

    PubMed

    Chassy, Philippe; Gobet, Fernand

    2013-01-01

    Considerable research has been carried out on visual search, with single or multiple targets. However, most studies have used artificial stimuli with low ecological validity. In addition, little is known about the effects of target complexity and expertise in visual search. Here, we investigate visual search in three conditions of complexity (detecting a king, detecting a check, and detecting a checkmate) with chess players of two levels of expertise (novices and club players). Results show that the influence of target complexity depends on level of structure of the visual display. Different functional relationships were found between artificial (random chess positions) and ecologically valid (game positions) stimuli: With artificial, but not with ecologically valid stimuli, a "pop out" effect was present when a target was visually more complex than distractors but could be captured by a memory chunk. This suggests that caution should be exercised when generalising from experiments using artificial stimuli with low ecological validity to real-life stimuli. PMID:23320084

  17. Ecological effects of mercury in aquatic ecosystems

    SciTech Connect

    Suchanek, T.H.; Richerson, P.J. [Univ. of California, Davis, CA (United States). Division of Environmental Studies

    1994-12-31

    As a result of former mining operations, roughly 100 tons of mercury were released into Clear Lake, California. In 1992 the authors conducted a baseline survey designed to evaluate the levels and potential effects of mercury within this aquatic ecosystem. Both surficial sediments and cores confirm a clear exponential decline in total mercury and methyl mercury as a function of distance from the mine site. The ratio of methyl/total mercury in surficial sediments, however, increases exponentially as a function of distance from the mine. Declines in total mercury in water were not as steep as for sediments. Plankton, oligochaetes and chironomids also exhibited exponential declines in total mercury but not methyl mercury as a function of distance from the mine. Patterns of invertebrate population and community level parameters will be discussed in relation to mercury and other potential pollutants. Fish showed increasing mercury levels with increasing body size and the following species specific differences: carp < silversides < channel catfish < largemouth bass. Some higher than expected levels of methyl mercury were found at sites distant from the mine. An hypothesis to explain these methyl mercury distributions as a function of bioavailability will be presented.

  18. Long Runs of Homozygosity Are Enriched for Deleterious Variation

    E-print Network

    Rosenberg, Noah

    to the main- tenance of deleterious variants. Here, we use exome sequencing to examine ROH in relation to the distribution of deleterious variation in 27 individuals of varying levels of apparent inbreeding from 6 human genetics.1­15 In humans, it has been argued that an individual genome can contain tens to hundreds

  19. Substitution Processes in Molecular Evolution. 111. Deleterious Alleles

    Microsoft Academic Search

    John H. Gillespie

    1994-01-01

    The substitution processes for various models of deleterious alleles are examined using computer simulations and mathematical analyses. Most of the work focuses on the house-ofcards model, which is a popular model of deleterious allele evolution. The rate of substitution is shown to be a concave function of the strength of selection as measured by a = 2Nu, where N is

  20. Estimate of the genomic mutation rate deleterious to overall fitness in E. coll

    NASA Astrophysics Data System (ADS)

    Kibota, Travis T.; Lynch, Michael

    1996-06-01

    MUTATIONS are a double-edged sword: they are the ultimate source of genetic variation upon which evolution depends, yet most mutations affecting fitness (viability and reproductive success) appear to be harmful1. Deleterious mutations of small effect can escape natural selection, and should accumulate in small populations2-4. Reduced fitness from deleterious-mutation accumulation may be important in the evolution of sex5-7, mate choice8,9, and diploid life-cycles10, and in the extinction of small populations11,12. Few empirical data exist, however. Minimum estimates of the genomic deleterious-mutation rate for viability in Drosophila melanogaster are surprisingly high1,13,14, leading to the conjecture that the rate for total fitness could exceed 1.0 mutation per individual per generation5,6. Here we use Escherichia coli to provide an estimate of the genomic deleterious-mutation rate for total fitness in a microbe. We estimate that the per-microbe rate of deleterious mutations is in excess of 0.0002.

  1. ECOLOGICAL TAX REFORM: Estimated Environmental and Employment Effects in British Columbia

    E-print Network

    i ECOLOGICAL TAX REFORM: Estimated Environmental and Employment Effects in British Columbia by Amy APPROVAL #12;iii Abstract Ecological tax reform involves implementing taxes on actions or outcome of actions which harm the environment. Although several European countries have implemented ecological tax

  2. Nontarget effects of an introduced biological control agent on deer mouse ecology

    Microsoft Academic Search

    Dean E. Pearson; Kevin S. McKelvey; Leonard F. Ruggiero

    2000-01-01

    Release of exotic insects as biological control agents is a common approach to controlling exotic plants. Though controversy\\u000a has ensued regarding the deleterious direct effects of biological control agents to non-target species, few have examined\\u000a the indirect effects of a ”well-behaved” biological control agent on native fauna. We studied a grassland in west-central\\u000a Montana infested with spotted knapweed (Centaurea maculosa)

  3. Identification of deleterious mutations within three human genomes

    PubMed Central

    Chun, Sung; Fay, Justin C.

    2009-01-01

    Each human carries a large number of deleterious mutations. Together, these mutations make a significant contribution to human disease. Identification of deleterious mutations within individual genome sequences could substantially impact an individual's health through personalized prevention and treatment of disease. Yet, distinguishing deleterious mutations from the massive number of nonfunctional variants that occur within a single genome is a considerable challenge. Using a comparative genomics data set of 32 vertebrate species we show that a likelihood ratio test (LRT) can accurately identify a subset of deleterious mutations that disrupt highly conserved amino acids within protein-coding sequences, which are likely to be unconditionally deleterious. The LRT is also able to identify known human disease alleles and performs as well as two commonly used heuristic methods, SIFT and PolyPhen. Application of the LRT to three human genomes reveals 796–837 deleterious mutations per individual, ?40% of which are estimated to be at <5% allele frequency. However, the overlap between predictions made by the LRT, SIFT, and PolyPhen, is low; 76% of predictions are unique to one of the three methods, and only 5% of predictions are shared across all three methods. Our results indicate that only a small subset of deleterious mutations can be reliably identified, but that this subset provides the raw material for personalized medicine. PMID:19602639

  4. Potential Biological and Ecological Effects of Flickering Artificial Light

    PubMed Central

    Inger, Richard; Bennie, Jonathan; Davies, Thomas W.; Gaston, Kevin J.

    2014-01-01

    Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered. PMID:24874801

  5. Ecological effects of contaminants and remedial actions in Bear Creek

    SciTech Connect

    Southworth, G.R.; Loar, J.M.; Ryon, M.G.; Smith, J.G.; Stewart, A.J. (Oak Ridge National Lab., TN (United States)); Burris, J.A. (C. E. Environmental, Inc., Tallahassee, FL (United States))

    1992-01-01

    Ecological studies of the Bear Creek watershed, which drains the area surrounding several Oak Ridge Y-12 Plant waste disposal facilities, were initiated in May 1984 and are continuing at present. These studies consisted of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek, and they were followed by a presently ongoing monitoring phase that involves reduced sampling intensities. The characterization phase utilized two approaches: (1) instream sampling of benthic invertebrate and fish communities in Bear Creek to identify spatial and temporal patterns in distribution and abundance and (2) laboratory bioassays on water samples from Bear Creek and selected tributaries to identify potential sources of toxicity to biota. The monitoring phase of the ecological program relates to the long-term goals of identifying and prioritizing contaminant sources and assessing the effectiveness of remedial actions. It continues activities of the characterization phase at less frequent intervals. The Bear Greek Valley is a watershed that drains the area surrounding several closed Oak Ridge Y-12 Plant waste disposal facilities. Past waste disposal practices in Bear Creek Valley resulted in contamination of Bear Creek and consequent ecological damage. Extensive remedial actions have been proposed at waste sites, and some of the have been implemented or are now underway. The proposed study plan consists of an initial, detailed characterization of the benthic invertebrate and fish communities in Bear Creek in the first year followed by a reduction in sampling intensity during the monitoring phase of the plan. The results of sampling conducted from May 1984 through early 1989 are presented in this report.

  6. The inevitability of unconditionally deleterious substitutions during adaptation.

    PubMed

    McCandlish, David M; Epstein, Charles L; Plotkin, Joshua B

    2014-05-01

    Studies on the genetics of adaptation from new mutations typically neglect the possibility that a deleterious mutation might fix. Nonetheless, here we show that, in many regimes, the first mutation to fix is most often deleterious, even when fitness is expected to increase in the long term. In particular, we prove that this phenomenon occurs under weak mutation for any house-of-cards model with an equilibrium distribution. We find that the same qualitative results hold under Fisher's geometric model. We also provide a simple intuition for the surprising prevalence of unconditionally deleterious substitutions during early adaptation. Importantly, the phenomenon we describe occurs on fitness landscapes without any local maxima and is therefore distinct from "valley crossing." Our results imply that the common practice of ignoring deleterious substitutions leads to qualitatively incorrect predictions in many regimes. Our results also have implications for the substitution process at equilibrium and for the response to a sudden decrease in population size. PMID:24410330

  7. Status and ecological effects of the world's largest carnivores.

    PubMed

    Ripple, William J; Estes, James A; Beschta, Robert L; Wilmers, Christopher C; Ritchie, Euan G; Hebblewhite, Mark; Berger, Joel; Elmhagen, Bodil; Letnic, Mike; Nelson, Michael P; Schmitz, Oswald J; Smith, Douglas W; Wallach, Arian D; Wirsing, Aaron J

    2014-01-10

    Large carnivores face serious threats and are experiencing massive declines in their populations and geographic ranges around the world. We highlight how these threats have affected the conservation status and ecological functioning of the 31 largest mammalian carnivores on Earth. Consistent with theory, empirical studies increasingly show that large carnivores have substantial effects on the structure and function of diverse ecosystems. Significant cascading trophic interactions, mediated by their prey or sympatric mesopredators, arise when some of these carnivores are extirpated from or repatriated to ecosystems. Unexpected effects of trophic cascades on various taxa and processes include changes to bird, mammal, invertebrate, and herpetofauna abundance or richness; subsidies to scavengers; altered disease dynamics; carbon sequestration; modified stream morphology; and crop damage. Promoting tolerance and coexistence with large carnivores is a crucial societal challenge that will ultimately determine the fate of Earth's largest carnivores and all that depends upon them, including humans. PMID:24408439

  8. Substitution processes in molecular evolution. III. Deleterious alleles.

    PubMed

    Gillespie, J H

    1994-11-01

    The substitution processes for various models of deleterious alleles are examined using computer simulations and mathematical analyses. Most of the work focuses on the house-of-cards model, which is a popular model of deleterious allele evolution. The rate of substitution is shown to be a concave function of the strength of selection as measured by alpha = 2N sigma, where N is the population size and sigma is the standard deviation of fitness. For alpha < 1, the house-of-cards model is essentially a neutral model; for alpha > 4, the model ceases to evolve. The stagnation for large alpha may be understood by appealing to the theory of records. The house-of-cards model evolves to a state where the vast majority of all mutations are deleterious, but precisely one-half of those mutations that fix are deleterious (the other half are advantageous). Thus, the model is not a model of exclusively deleterious evolution as is frequently claimed. It is argued that there are no biologically reasonable models of molecular evolution where the vast majority of all substitutions are deleterious. Other models examined include the exponential and gamma shift models, the Hartl-Dykhuizen-Dean (HDD) model, and the optimum model. Of all those examined, only the optimum and HDD models appear to be reasonable candidates for silent evolution. None of the models are viewed as good candidates for protein evolution, as none are both biologically reasonable and exhibit the variability in substitutions commonly observed in protein sequence data. PMID:7851786

  9. Physiological Ecology of Freshwater Mussel Communities: Effects of Temperature on Community Structure and Ecological Services.

    NASA Astrophysics Data System (ADS)

    Spooner, D. E.; Vaughn, C. C.

    2005-05-01

    Recent work suggests that freshwater mussel communities significantly influence stream ecosystem function through benthic-pelagic coupling of energy and nutrients. Mussel beds increase sediment organic matter and benthic algal production, facilitating the abundance and diversity of co-occurring benthic invertebrates. The magnitude of these effects appear to be regulated by abiotic factors such as temperature and flow, which influence hydraulic residence time and biological rates of reaction. We are using an integrative approach to examine the role of temperature on measures of physiological condition (metabolic rate, glycogen concentration, RNA: DNA) and measures of ecosystem services (nutrient excretion, biodeposition and clearance rate). Eight different species of unionids were removed from a mussel bed in the Little River, OK and acclimated to four temperatures (5, 15, 25, and 35C) for two weeks prior to the experiment. Measures of condition and ecosystem services were taken for all species at each temperature. Data collected to date suggest that there is significant variation in species-specific thermal performance. These performance curves influence resource acquisition, potentially shaping community structure (species dominance) and subsequent ecological function.

  10. Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska

    E-print Network

    542 Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska By Roger J. ReedKernan, Director Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska By ROGER J. REED insects 3 Water samples 3 Marine clams and plankton 3 Insecticide application 4 Insecticide analyses 4

  11. On the Likelihood of Single-Walled Carbon Nanotubes Causing Adverse Marine Ecological Effects

    EPA Science Inventory

    This brief article discusses the ecological effects of single-walled carbon nanotubes (SWNTs)in the marine environment. Based on new research and a review of the scientific literature, the paper concludes that SWNTs are unlikely to cause adverse ecological effects in the marine ...

  12. The Ecology of Infectious Disease: Effects of Host Diversity and Community Composition on Lyme Disease Risk

    E-print Network

    Cochran-Stafira, D. Liane

    The Ecology of Infectious Disease: Effects of Host Diversity and Community Composition on Lyme ecology of infectious disease: Effects of host diversity and community composition on Lyme disease risk to Lyme- disease-bearing ticks. We tested the DilutionEffectmodel, which predictsthat high species

  13. Inbreeding load, average dominance and the mutation rate for mildly deleterious alleles in Mimulus guttatus.

    PubMed Central

    Willis, J H

    1999-01-01

    The goal of this study is to provide information on the genetics of inbreeding depression in a primarily outcrossing population of Mimulus guttatus. Previous studies of this population indicate that there is tremendous inbreeding depression for nearly every fitness component and that almost all of this inbreeding depression is due to mildly deleterious alleles rather than recessive lethals or steriles. In this article I assayed the homozygous and heterozygous fitnesses of 184 highly inbred lines extracted from a natural population. Natural selection during the five generations of selfing involved in line formation essentially eliminated major deleterious alleles but was ineffective in purging alleles with minor fitness effects and did not appreciably diminish overall levels of inbreeding depression. Estimates of the average degree of dominance of these mildly deleterious alleles, obtained from the regression of heterozygous fitness on the sum of parental homozygous fitness, indicate that the detrimental alleles are partially recessive for most fitness traits, with h approximately 0.15 for cumulative measures of fitness. The inbreeding load, B, for total fitness is approximately 1.0 in this experiment. These results are consistent with the hypothesis that spontaneous mildly deleterious mutations occur at a rate >0.1 mutation per genome per generation. PMID:10581293

  14. Ecological Effects and In-situ Detection of Particulate Contaminants in Aqueous Environments

    E-print Network

    Fuller, Christopher Byron

    2012-07-16

    The ecological effects and mechanistic efficiency of chemical oil spill countermeasures must be evaluated prior to their ethical application during real spill response scenarios. Equally important is the ability to monitor the effectiveness of any...

  15. Ecological effects on gut bacterial communities in wild bumblebee colonies.

    PubMed

    Koch, Hauke; Cisarovsky, Gabriel; Schmid-Hempel, Paul

    2012-11-01

    1. Animal hosts harbour diverse and often specific bacterial communities (microbiota) in their gut. These microbiota can provide crucial services to the host such as aiding in digestion of food and immune defence. However, the ecological factors correlating with and eventually shaping these microbiota under natural conditions are poorly understood. 2. Bumblebees have recently been shown to possess simple and highly specific microbiota. We here examine the dynamics of these microbiota in field colonies of the bumblebee Bombus terrestris over one season. The gut bacteria were assessed with culture-independent methods, that is, with terminal restriction fragment length profiles of the 16S rRNA gene. 3. To further understand the factors that affect the microbiota, we experimentally manipulated field-placed colonies in a fully factorial experiment by providing additional food or by priming the workers' immune system by injecting heat-killed bacteria. We furthermore looked at possible correlates of diversity and composition of the microbiota for (i) natural infections with the microbial parasites Crithidia bombi and Nosema bombi, (ii) bumblebee worker size, (iii) colony identity, and (iv) colony age. 4. We found an increase in diversity of the microbiota in individuals naturally infected with either C. bombi or N. bombi. Crithidia bombi infections, however, appear to be only indirectly linked with higher microbial diversity when comparing colonies. The treatments of priming the immune system with heat-killed bacteria and additional food supply, as well as host body size, had no effect on the diversity or composition of the microbiota. Host colony identity had only a weak effect on the composition of the microbiota at the level of resolution of our method. We found both significant increases and decreases in the relative abundance of selected bacterial taxa over the season. 5. We present the first study on the ecological dynamics of gut microbiota in bumblebees and identify parasite infections, colony identity and colony age as important factors influencing the diversity and composition of the bacterial communities. The absence of an effect of our otherwise effective experimental treatments suggests a remarkable ability of the host to maintain a homoeostasis in this community under widely different environments. PMID:22708631

  16. Ecological and Evolutionary Effects of Dispersal on Freshwater Zooplankton

    ERIC Educational Resources Information Center

    Allen, Michael R.

    2009-01-01

    A recent focus on contemporary evolution and the connections between communities has sought to more closely integrate ecology with evolutionary biology. Studies of coevolutionary dynamics, life history evolution, and rapid local adaptation demonstrate that ecological circumstances can dictate evolutionary trajectories. Thus, variation in species…

  17. Limited Dispersal, Deleterious Mutations and the Evolution of Sex

    PubMed Central

    Peck, J. R.

    1996-01-01

    This study presents a mathematical model that allows for some offspring to be dispersed at random, while others stay close to their mothers. A single genetic locus is assumed to control fertility, and this locus is subject to the occurrence of deleterious mutations. It is shown that, at equilibrium, the frequency of deleterious mutations in the population is inversely related to the rate of dispersal. This is because dispersal of offspring leads to enhanced competition among adults. The results also show that sexual reproduction can lead to a decrease in the equilibrium frequency of deleterious mutations. The reason for this relationship is that sex involves the dispersal of genetic material, and thus, like the dispersal of offspring, sex enhances competition among adults. The model is described using the example of a hermaphroditic plant population. However, the results should apply to animal populations as well. PMID:8849911

  18. A synthesis of the "Ecological Effects of Reservoir Operations at Blue Mesa Reservoir" Project

    E-print Network

    Bureau of Reclamation Technical Service Center Ecological Planning and Assessment Group Denver, Colorado June 2005 #12;2 RECLAMATION A synthesis of the "Ecological Effects of Reservoir Operations at Blue Mesa: U.S. Department of the Interior Bureau of Reclamation By: Dr. Brett M. Johnson and Dr. Marci L

  19. Alien species in fresh waters: ecological effects, interactions with other stressors, and prospects for the

    E-print Network

    Alien species in fresh waters: ecological effects, interactions with other stressors, and prospects dozens of alien species. 2. Invasions are highly nonrandom with respect to the taxonomic identity, which probably have been underestimated as an ecological force. 4. The number of alien species

  20. Ecological effects of small-scale cutting of Philippine mangrove forests

    E-print Network

    Walters, Bradley B.

    Ecological effects of small-scale cutting of Philippine mangrove forests Bradley B. Walters of mangrove forests in the Philippines. Information for the study was obtained through the application of extensive bio-ecological assessments of forests and interviews of forest users. Cut mangrove forests were

  1. The evolution of selfing is accompanied by reduced efficacy of selection and purging of deleterious mutations.

    PubMed

    Arunkumar, Ramesh; Ness, Rob W; Wright, Stephen I; Barrett, Spencer C H

    2015-03-01

    The transition from outcrossing to selfing is predicted to reduce the genome-wide efficacy of selection because of the lower effective population size (Ne) that accompanies this change in mating system. However, strongly recessive deleterious mutations exposed in the homozygous backgrounds of selfers should be under strong purifying selection. Here, we examine estimates of the distribution of fitness effects (DFE) and changes in the magnitude of effective selection coefficients (Nes) acting on mutations during the transition from outcrossing to selfing. Using forward simulations, we investigated the ability of a DFE inference approach to detect the joint influence of mating system and the dominance of deleterious mutations on selection efficacy. We investigated predictions from our simulations in the annual plant Eichhornia paniculata, in which selfing has evolved from outcrossing on multiple occasions. We used range-wide sampling to generate population genomic datasets and identified nonsynonymous and synonymous polymorphisms segregating in outcrossing and selfing populations. We found that the transition to selfing was accompanied by a change in the DFE, with a larger fraction of effectively neutral sites (Nes < 1), a result consistent with the effects of reduced Ne in selfers. Moreover, an increased proportion of sites in selfers were under strong purifying selection (Nes > 100), and simulations suggest that this is due to the exposure of recessive deleterious mutations. We conclude that the transition to selfing has been accompanied by the genome-wide influences of reduced Ne and strong purifying selection against deleterious recessive mutations, an example of purging at the molecular level. PMID:25552275

  2. Influence of the grain size on deleterious phase precipitation in superduplex stainless steel UNS S32750

    SciTech Connect

    Pardal, J.M. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica, Rua Passo da Patria, 156-CEP 24210-240, Niteroi/Brazil (Brazil); Tavares, S.S.M. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica, Rua Passo da Patria, 156-CEP 24210-240, Niteroi/Brazil (Brazil)], E-mail: ssmtavares@terra.com.br; Fonseca, M. Cindra; Souza, J.A. de; Corte, R.R.A. [Universidade Federal Fluminense, Departamento de Engenharia Mecanica, Rua Passo da Patria, 156-CEP 24210-240, Niteroi/Brazil (Brazil); Abreu, H.F.G. de [Universidade Federal do Ceara, Departamento de Engenharia Metalugica e de Materiais, Campus do Pici Bl. 702, Fortaleza, CE, CEP 60.455-760 (Brazil)

    2009-03-15

    In the present work, the effect of grain size on deleterious phase precipitation in a superduplex stainless steel was investigated. The materials studied were heat treated isothermally at 800 deg. C, 850 deg. C and 900 deg. C for times up to 120 min. Hardness tests, light optical microscopy, scanning electron microscopy and X-ray diffraction were carried out to detect sigma and other harmful precipitate phases. The ferritic and austenitic grain sizes in the solution treated condition of the two steels analyzed were measured by electron backscattered diffraction (EBSD). Cyclic polarization corrosion tests were performed to evaluate the effect of grain size on the corrosion resistance. The results presented show that the precipitation of deleterious phases such as {chi}, {sigma} and {gamma}{sub 2}, which can occur during welding and forming operations, is retarded by grain growth.

  3. [Assessment of ecological environment effects of coastal development in Hebei Province, China].

    PubMed

    Cui, Li-Tuo; Li, Zhi-Wei

    2014-07-01

    Through the analysis of the development activities and the ecological environment in coastal of Hebei Province, China, an index system for evaluating the ecological environment effect, composed of 28 indices, was set up by the pressure, state and response subsystems. Using the comprehensive index evaluation method, the integrated effects of ecological environment index (EI) was calculated and its grading criterion was founded. The results showed that the ecological environment effect of Hebei Province coastal development varied from being relatively small, normal and then relatively large from 1984 to 2010, and its acceptance degree evolved from being acceptable to being unacceptable. Because the resource and environment pressures caused by coastal development were serious and a delay existed in the state relative to the response, the improvement of various measures in the response subsystem did not show a positive effect on the state, and the environmental quality of ocean showed a degrading trend. Due to the differences in coastal development pattern and strength, the ecological environment effect of development activities showed some spatial differences. The ecological environment effect of Qinhuangdao coastal development was the minimum, followed by Cangzhou and Tangshan. Cangzhou and Tangshan had reached unacceptable levels and needed to further strengthen the restoration and protection of ecological environment. PMID:25345059

  4. Hitchhiking of deleterious alleles and the cost of adaptation in partially selfing species.

    PubMed

    Hartfield, Matthew; Glémin, Sylvain

    2014-01-01

    Self-fertilization is generally seen to be disadvantageous in the long term. It increases genetic drift, which subsequently reduces polymorphism and the efficiency of selection, which also challenges adaptation. However, high selfing rates can increase the fixation probability of recessive beneficial mutations, but existing theory has generally not accounted for the effect of linked sites. Here, we analyze a model for the fixation probability of deleterious mutants that hitchhike with selective sweeps in diploid, partially selfing populations. Approximate analytical solutions show that, conditional on the sweep not being lost by drift, higher inbreeding rates increase the fixation probability of the deleterious allele, due to the resulting reduction in polymorphism and effective recombination. When extending the analysis to consider a distribution of deleterious alleles, as well as the average fitness increase after a sweep, we find that beneficial alleles generally need to be more recessive than the previously assumed dominance threshold (h < 1/2) for selfing to be beneficial from one-locus theory. Our results highlight that recombination aiding the efficiency of selection on multiple loci amplifies the fitness benefits of outcrossing over selfing, compared to results obtained from one-locus theory. This effect additionally increases the parameter range under which obligate outcrossing is beneficial over partial selfing. PMID:24240529

  5. DELETERIOUS RHIZOBACTERIA ENHANCE THE ACTION OF NATURAL HERBICIDAL PRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizobacteria have been shown to suppress weed growth in field tests. The efficacy of these bacteria in weed biological control schemes potentially could be enhanced if combined with other herbicidal agents. This study compared the relative inhibitory action of the deleterious rhizobacterium (DRB) P...

  6. Epistasis between deleterious mutations and the evolution of

    E-print Network

    Bonhoeffer, Sebastian

    Epistasis between deleterious mutations and the evolution of recombination Roger D. Kouyos* , Olin¨tsstrasse 16, 8092, Zu¨ rich, Switzerland Epistasis and the evolution of recombination are closely intertwined: epistasis generates linkage disequilibria (i.e. statistical associations between alleles), whereas recom

  7. HISTORICAL ANALYSIS OF ECOLOGICAL EFFECTS: A USEFUL EDUCATIONAL TOOL

    EPA Science Inventory

    An historical analysis that presents the ecological consequences of development can be a valuable educational tool for citizens, students, and environmental managers. In highly impacted areas, the cumulative impacts of multiple stressors can result in complex environmental condit...

  8. Cells that produce deleterious autoreactive antibodies are vulnerable to suicide.

    PubMed

    Niu, Haitao; Leung, Danny T M; Ma, Chun Hung; Law, Eric C Y; Tam, Frankie C H; Lim, Pak-Leong

    2008-08-01

    It is puzzling how autoreactive B cells that escape self-tolerance mechanisms manage to produce Abs that target vital cellular processes without succumbing themselves to the potentially deleterious effects of these proteins. We report that censorship indeed exists at this level: when the Ab synthesis in the cell is up-regulated in IL-6-enriched environments (e.g., adjuvant-primed mouse peritoneum), the cell dies of the increased intracellular binding between the Ab and the cellular autoantigen. In the case in which telomerase is the autoantigen, mouse hybridoma cells synthesizing such an autoantibody, which appeared to grow well in culture, could not grow in syngeneic BALB/c mice to form ascites, but grew nevertheless in athymic siblings. Culture experiments demonstrated that peritoneal cell-derived IL-6 (and accessory factors) affected the growth and functions of the hybridoma cells, including the induction of mitochondria-based apoptosis. Electron microscopy revealed an abundance of Abs in the nuclear chromatin of IL-6-stimulated cells, presumably piggy-backed there by telomerase from the cytosol. This nuclear presence was confirmed by light microscopy analysis of isolated nuclei. In two other cases, hybridoma cells synthesizing an autoantibody to GTP or osteopontin also showed similar growth inhibition in vivo. In all cases, Ab function was crucial to the demise of the cells. Thus, autoreactive cells, which synthesize autoantibodies to certain intracellular Ags, live delicately between life and death depending on the cytokine microenvironment. Paradoxically, IL-6, which is normally growth-potentiating for B cells, is proapoptotic for these cells. The findings reveal potential strategies and targets for immunotherapy. PMID:18641365

  9. Most of rare missense alleles in humans are deleterious:implications for evolution of complex disease and associationstudies

    SciTech Connect

    Kryukov, Gregory V.; Pennacchio, Len A.; Sunyaev, Shamil R.

    2006-10-24

    The accumulation of mildly deleterious missense mutations inindividual human genomes has been proposed to be a genetic basis forcomplex diseases. The plausibility of this hypothesis depends onquantitative estimates of the prevalence of mildly deleterious de novomutations and polymorphic variants in humans and on the intensity ofselective pressure against them. We combined analysis of mutationscausing human Mendelian diseases, human-chimpanzee divergence andsystematic data on human SNPs and found that about 20 percent of newmissense mutations in humans result in a loss of function, while about 27percent are effectively neutral. Thus, more than half of new missensemutations have mildly deleterious effects. These mutations give rise tomany low frequency deleterious allelic variants in the human populationas evident from a new dataset of 37 genes sequenced in over 1,500individual human chromosomes. Surprisingly, up to 70 percent of lowfrequency missense alleles are mildly deleterious and associated with aheterozygous fitness loss in the range 0.001-0.003. Thus, the low allelefrequency of an amino acid variant can by itself serve as a predictor ofits functional significance. Several recent studies have reported asignificant excess of rare missense variants in disease populationscompared to controls in candidate genes or pathways. These studies wouldbe unlikely to work if most rare variants were neutral or if rarevariants were not a significant contributor to the genetic component ofphenotypic inheritance. Our results provide a justification for thesetypes of candidate gene (pathway) association studies and imply thatmutation-selection balance may be a feasible mechanism for evolution ofsome common diseases.

  10. Designing impact assessments for evaluating ecological effects of agricultural conservation practices on streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation practices are regularly implemented within agricultural watersheds throughout the United States without evaluating their ecological impacts. Scientific evaluations documenting how habitat and aquatic biota within streams respond to these practices are needed for evaluating the effects o...

  11. Landscape Sources, Ecological Effects, and Management of Nutrients in Lakes of Northeastern USA

    EPA Science Inventory

    Lakes face escalating pressures associated with land cover change and growing human populations. Ecological responses provide context for identifying stressor severity, land use impacts, and management effectiveness. We used EPA National Lakes Assessment data and GIS to develop i...

  12. LANDSCAPE-SCALE EFFECTS OF TOXIC EVENTS FOR ECOLOGICAL RISK ASSESSMENT

    EPA Science Inventory

    The effect of spatial heterogeneity on response of organisms has rarely been considered in ecological risk assessment or in ecotoxicological studies. ncreased and widespread use of agricultural pesticides has been linked with population declines of plants, invertebrate and verteb...

  13. Environmental variability and the ecological effects of spawning Pacific salmon on stream biofilm

    E-print Network

    Tiegs, Scott

    Environmental variability and the ecological effects of spawning Pacific salmon on stream biofilm by resource subsidies and disturbance by ecosystem engineering) on benthic biofilm. 2. We sampled seven, stream environmental characteristics and their influence on responses of benthic biofilm [mean

  14. Fashion Merchandising & Retail Studies, BS IPC: 2013 School of Human Ecology EFFECTIVE: 2013

    E-print Network

    Selmic, Sandra

    Fashion Merchandising & Retail Studies, BS IPC: 2013 School of Human Ecology EFFECTIVE: 2013 STUDENT: CWID#: DATE ENTERED: ADVISOR: GENERAL EDUCATION REQUIREMENTS: FASHION MERCHANDISING & RETAIL the following: Accounting, Art, Fashion Merchandising & Retail Studies. All must be approved by academic advisor

  15. An Overview of Stream Ecological Responses to Urban Effects and Management Practices in New England

    EPA Science Inventory

    Many recent studies have found large changes in ecological conditions related to small increases in watershed development. Future development and restoration practices will benefit from better documenting the effectiveness of management practices. We present (1) a brief summary o...

  16. Extraordinary Sex Ratios: Cultural Effects on Ecological Consequences

    PubMed Central

    Molnár, Ferenc; Caraco, Thomas; Korniss, Gyorgy

    2012-01-01

    We model sex-structured population dynamics to analyze pairwise competition between groups differing both genetically and culturally. A sex-ratio allele is expressed in the heterogametic sex only, so that assumptions of Fisher’s analysis do not apply. Sex-ratio evolution drives cultural evolution of a group-associated trait governing mortality in the homogametic sex. The two-sex dynamics under resource limitation induces a strong Allee effect that depends on both sex ratio and cultural trait values. We describe the resulting threshold, separating extinction from positive growth, as a function of female and male densities. When initial conditions avoid extinction due to the Allee effect, different sex ratios cannot coexist; in our model, greater female allocation always invades and excludes a lesser allocation. But the culturally transmitted trait interacts with the sex ratio to determine the ecological consequences of successful invasion. The invading female allocation may permit population persistence at self-regulated equilibrium. For this case, the resident culture may be excluded, or may coexist with the invader culture. That is, a single sex-ratio allele in females and a cultural dimorphism in male mortality can persist; a low-mortality resident trait is maintained by father-to-son cultural transmission. Otherwise, the successfully invading female allocation excludes the resident allele and culture and then drives the population to extinction via a shortage of males. Finally, we show that the results obtained under homogeneous mixing hold, with caveats, in a spatially explicit model with local mating and diffusive dispersal in both sexes. PMID:22952669

  17. Under the radar: mitigating enigmatic ecological impacts.

    PubMed

    Raiter, Keren G; Possingham, Hugh P; Prober, Suzanne M; Hobbs, Richard J

    2014-11-01

    Identifying the deleterious ecological effects of developments, such as roads, mining, and urban expansion, is essential for informing development decisions and identifying appropriate mitigation actions. However, there are many types of ecological impacts that slip 'under the radar' of conventional impact evaluations and undermine the potential for successful impact mitigation (including offsets). These 'enigmatic' impacts include those that are small but act cumulatively; those outside of the area directly considered in the evaluation; those not detectable with the methods, paradigms, or spatiotemporal scales used to detect them; those facilitated, but not directly caused, by development; and synergistic impact interactions. Here, we propose a framework for conceptualising enigmatic impacts and discuss ways to address them. PMID:25269749

  18. Flow effects on benthic stream invertebrates and ecological processes

    NASA Astrophysics Data System (ADS)

    Koprivsek, Maja; Brilly, Mitja

    2010-05-01

    Flow is the main abiotic factor in the streams. Flow affects the organisms in many direct and indirect ways. The organisms are directly affected by various hydrodynamic forces and mass transfer processes like drag forces, drift, shear stress, food and gases supply and washing metabolites away. Indirect effects on the organisms are determining and distribution of the particle size and structure of the substrate and determining the morphology of riverbeds. Flow does not affect only on individual organism, but also on many ecological effects. To expose just the most important: dispersal of the organisms, habitat use, resource acquisition, competition and predator-prey interactions. Stream invertebrates are adapted to the various flow conditions in many kinds of way. Some of them are avoiding the high flow with living in a hyporeic zone, while the others are adapted to flow with physical adaptations (the way of feeding, respiration, osmoregulation and resistance to draught), morphological adaptations (dorsoventrally flattened shape of organism, streamlined shape of organism, heterogeneous suckers, silk, claws, swimming hair, bristles and ballast gravel) or with behaviour. As the flow characteristics in a particular stream vary over a broad range of space and time scales, it is necessary to measure accurately the velocity in places where the organisms are present to determine the actual impact of flow on aquatic organisms. By measuring the mean flow at individual vertical in a single cross-section, we cannot get any information about the velocity situation close to the bottom of the riverbed where the stream invertebrates are living. Just measuring the velocity near the bottom is a major problem, as technologies for measuring the velocity and flow of natural watercourses is not adapted to measure so close to the bottom. New researches in the last two decades has shown that the thickness of laminar border layer of stones in the stream is only a few 100 micrometers, what is not enough to make a shelter for stream invertebrates. It serves as a shelter only for microorganisms, but the stream invertebrates have to avoid the swift flow or adapt to flow with adaptations described above. To understand what conditions are subject to aquatic organisms and how to adapt, it is essential. Both, knowledge of fluid dynamics in natural watercourses and ecology are needed to understand to what conditions the stream invertebrates are exposed and how they cope with them. Some investigations of near bed flow will be performed on the Glinšica stream. The acoustic Doppler velocimeter SonTek will be adapted to measure so close to the bed as possible. It is expected we should be able to measure the velocities just 0,5 cm above the bed surface. We intend to measure the velocities on a natural and on a regulated reach and then compare the results.

  19. Climate Change Has Cascading Ecological Effects on Mountain Ecosystems

    NASA Astrophysics Data System (ADS)

    Fagre, D. B.

    2007-12-01

    Evidence that ecosystems of the Northern Rocky Mountains are responding to climate change abounds. Alpine glaciers, as iconic landscape features, are disappearing rapidly with some glaciers losing one half of their area in five years. A model developed in the 1990s to predict future rates of melt has proved too conservative when compared to recent measurements. The largest glaciers in Glacier National Park are almost 10 years ahead of schedule in their retreat. The cascading ecological effects of losing glaciers in high-elevation watersheds includes shifts in distribution and dominance of temperature-sensitive stream macroinvertebrates as stream volume dwindles (or disappears) in later summer months and water temperatures increase. Critical spawning areas for threatened bull trout (Salvelinus confluentus) will be lost without the consistent supply of cold water that melting snow and ice provide and raise management questions regarding the efficacy of recovery efforts. Snowpacks are documented as becoming smaller and melting earlier in the spring, facilitating the invasion of subalpine meadows by trees and reducing habitat for current alpine wildlife. Even vital ecosystem disturbances, such as periodic snow avalanches that clear mountain slope forests, have been shown by tree-ring studies to be responsive to climatic trends and are likely to become less prevalent. Monitoring of high-elevation mountain environments is difficult and has largely been opportunistic despite the fact that these areas have experienced three times the temperature increases over the past century when compared to lowland environments. A system of alpine observatories is sorely needed. Tighter integration of mountains studies, and comparisons among diverse mountain systems of the western U.S. has been initiated by the USGS-sponsored Western Mountain Initiative and the Consortium for Integrated Climate Research in Western Mountains to begin addressing this need.

  20. Effects of road age and distance on plant biodiversity: a case study in the Yellow River Delta of China

    Microsoft Academic Search

    Sheng-Lan Zeng; Ting-Ting Zhang; Yu Gao; Zu-Tao Ouyang; Jia-Kuan Chen; Bo Li; Bin Zhao

    2011-01-01

    A majority of ecological studies of roads have usually focused on their deleterious effect, and these preconceptions have\\u000a hampered a full evaluation of ecological functions of roads. We examined the effect of road disturbance on plant communities\\u000a by investigating roadside vegetation in the protogenic road ecosystem of the Yellow River Delta (YRD), China. Specifically,\\u000a we examined the effect of distance

  1. The ecological effectiveness of agri-environment schemes in different agricultural landscapes in The Netherlands

    Microsoft Academic Search

    DAVID KLEIJN; FRANK BERENDSE; RUBEN SMIT; NIELS GILISSEN; JOHN SMIT; BASTIAAN BRAK; ROLF GROENEVELD

    2004-01-01

    Agri-environment schemes are an instrument used by western European countries to counteract the negative effects of contemporary agriculture on biodiversity, but not much is known about their effectiveness. We investigated the ecological effects of Dutch agri-environment schemes aimed at promoting botanical diversity or meadow birds, and we tested whether the effectiveness of the schemes depends on landscape type or structure.

  2. Limited dispersal, deleterious mutations and the evolution of sex

    SciTech Connect

    Peck, J.R. [Univ. of Sussex, Brighton (United Kingdom)

    1996-03-01

    This study presents a mathematical model that allows for some offspring to be dispersed at random, while others stay close to their mothers. A single genetic locus is assumed to control fertility, and this locus is subject to the occurrence of deletions mutations. It is shown that, at equilibrium, the frequency of deleterious mutations in the population is inversely related to the rate of dispersal. The results also show that sexual reproduction can lead to a decrease in the equilibrium frequency of deleterious mutations. The reason for this relationship is that sex involves the dispersal of genetic material, and thus, like the dispersal of offspring, sex enhances competition among adults. The model is described using the example of a hermaphroditic plant population. However, the results should apply to animal populations as well. 36 refs., 1 fig.

  3. Amino acid composition of proteins reduces deleterious impact of mutations

    PubMed Central

    Hormoz, Sahand

    2013-01-01

    The evolutionary origin of amino acid occurrence frequencies in proteins (composition) is not yet fully understood. We suggest that protein composition works alongside the genetic code to minimize impact of mutations on protein structure. First, we propose a novel method for estimating thermodynamic stability of proteins whose sequence is constrained to a fixed composition. Second, we quantify the average deleterious impact of substituting one amino acid with another. Natural proteome compositions are special in at least two ways: 1) Natural compositions do not generate more stable proteins than the average random composition, however, they result in proteins that are less susceptible to damage from mutations. 2) Natural proteome compositions that result in more stable proteins (i.e. those of thermophiles) are also tuned to have a higher tolerance for mutations. This is consistent with the observation that environmental factors selecting for more stable proteins also enhance the deleterious impact of mutations. PMID:24108121

  4. On Ohta's hypothesis: Most amino acid substitutions are deleterious

    Microsoft Academic Search

    John H. Gillespie

    1995-01-01

    Ohta's hypothesis that most amino acid substitutions are deleterious grew out of a class of population-genetics models called shift models. Recently, shift models have been shown to be biologically unreasonable and have been replaced by a more plausible house-of-cards model. In this paper, the simplest form of the house-of-cards models is shown to be incompatible with most of the major

  5. Environmental effects of increased coal utilization: ecological effects of gaseous emissions from coal combustion.

    PubMed Central

    Glass, N R

    1979-01-01

    This report is limited to an evaluation of the ecological and environmental effects of gaseous emissions and aerosols of various types which result from coal combustion. It deals with NOx, SOx, fine particulate, photochemical oxidant and acid precipitation as these pollutants affect natural and managed resources and ecosystems. Also, synergistic effects involving two or more pollutants are evaluated as well as ecosystem level effects of gaseous pollutants. There is a brief summary of the effects on materials and atmospheric visibility of increased coal combustion. The economic implications of ecological effects are identified to the extent they can be determined within acceptable limits. Aquatic and terrestrial effects are distinguished where the pollutants in question are clearly problems in both media. At present, acid precipitation is most abundant in the north central and northeastern states. Total SOx and NOx emissions are projected to remain high in these regions while increasing relatively more in the western than in the eastern regions of the country. A variety of ecological processes are affected and altered by air pollution. Such processes include community succession and retrogression, nutrient biogeochemical cycling, photosynthetic activity, primary and secondary productivity, species diversity and community stability. Estimates of the non health-related cost of air pollutants range from several hundred million dollars to $1.7 billion dollars per year. In general, these estimates include only those relatively easily measured considerations such as the known losses to cultivate crops from acute air pollution episodes or the cost of frequent repainting required as a result of air pollution. No substantial nationwide estimates of losses to forest productivity, natural ecosystem productivity which is tapped by domestic grazing animals and wildlife, and other significant dollar losses are available. PMID:44247

  6. Ecological Effects of Weather Modification: A Problem Analysis.

    ERIC Educational Resources Information Center

    Cooper, Charles F.; Jolly, William C.

    This publication reviews the potential hazards to the environment of weather modification techniques as they eventually become capable of producing large scale weather pattern modifications. Such weather modifications could result in ecological changes which would generally require several years to be fully evident, including the alteration of…

  7. Landscape ecology: the effect of pattern on process

    Microsoft Academic Search

    Monica Goigel Turner

    1989-01-01

    Consideration of spatial dynamics in many areas of ecology has received increased attention during the past decade. For example, the role of disturbance in creating and maintaining a spatial mosaic in the rocky intertidal zone was studied. Patch size could be predicted very well by using a model based on past patterns of disturbance and on measured patterns of mussel

  8. Ecological effects of introduced tree species in Britain

    Microsoft Academic Search

    G. F. Peterken

    2001-01-01

    Non-native trees have been introduced to Britain and native trees have been redistributed for over 2000 years, but most species were introduced in the last 400 years, and the ecological consequences have not yet been fully manifested. Introduction has been followed by various forms of adaptation to British conditions: (i) genetic changes in the trees themselves, (ii) assimilation into forest

  9. THE EFFECTS OF PATCH SHAPE ON INDIGO BUNTINGS:; EVIDENCE FOR AN ECOLOGICAL TRAP

    Microsoft Academic Search

    AIMEE J. WELDON; NICK M. HADDAD

    2005-01-01

    Weldon, Aimee, J., and Nick M. Haddad. 2005. The effect of patch shape on indigo buntings: Evidence for an ecological trap. Ecology 86(6):1422-1431.;\\u000a;\\u000aAbstract. Habitat loss and fragmentation have led to a widespread increase in the;\\u000aproportion of edge habitat in the landscape. Disturbance-dependent bird species are widely;\\u000aassumed to benefit from these edges. However, anthropogenic edges may concentrate

  10. LineUp: Identifying Deleterious Mutations Using Protein Domain Alignment - Brady Bernard, TCGA Scientific Symposium 2014

    Cancer.gov

    Home News and Events Multimedia Library Videos LineUp: Identifying Deleterious Mutations Using Protein Domain Alignment - Brady Bernard LineUp: Identifying Deleterious Mutations Using Protein Domain Alignment - Brady Bernard, TCGA Scientific Symposium

  11. Increasing Public Access to Scientific Research through Stakeholder Involvement: Ecological Effects of Sea Level Rise in the Northern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Hagen, S. C.; Stephens, S. H.; DeLorme, D. E.; Ruple, D.; Graham, L.

    2013-12-01

    Sea level rise (SLR) has the potential to have a myriad of deleterious effects on coastal ecology and human infrastructure. Stakeholders, including managers of coastal resources, must be aware of potential consequences of SLR and adjust their plans accordingly to protect and preserve the resources under their care. Members of the public, particularly those who live or work in coastal areas, should also be informed about the results of scientific research on the effects of SLR. However, research results are frequently published in venues or formats to which resource managers and the broader public have limited access. It is imperative for scientists to move beyond traditional publication venues in order to more effectively disseminate the results of their research (Dennison, W. 2007, Estu. Coast. Shelf Sci. 77, 185). One potentially effective way to advance public access to research is to incorporate stakeholder involvement into the research project process in order to target study objectives and tailor communication products toward stakeholder needs (Lemos, M. & Morehouse, B. 2005, Glob. Env. Chg. 15, 57). However, it is important to manage communication and clarify participant expectations during this type of research (Gawith, M. et al. 2009, Glob. Env. Chg. 19, 113). This presentation describes the process being undertaken by an ongoing 5-year multi-disciplinary NOAA-funded project, Ecological Effects of Sea Level Rise in the Northern Gulf of Mexico (EESLR-NGOM), to improve accessibility and utility of scientific research results through stakeholder engagement. The EESLR-NGOM project is assessing the ecological risks from SLR along the Mississippi, Alabama and Florida Panhandle coasts, coastal habitats, and floodplains. It has incorporated stakeholder involvement throughout the research process so as to better target and tailor the emerging research products to meet resource managers' needs, as well as to facilitate eventual public dissemination of results. An important component of the EESLR-NGOM project is annual stakeholder committee workshops that engage regional coastal resource managers. These workshops are designed to identify managers' concerns about the scientific project objectives, solicit input on the content and format of the emerging research products, identify gaps in products and target audiences, and connect this project to other ongoing SLR research and extension efforts. We describe how this innovative project process has functioned to shape scientific objectives, the eventual SLR impact decision support tools, and other products that will help managers and the public use the project's results most effectively.

  12. Effect of coal mining on regional ecological footprint based on GIS

    NASA Astrophysics Data System (ADS)

    Chen, Qiu-ji; Kong, Yun-feng; Zhang, Hong-bo

    2006-10-01

    Coal mining has brought a plenty of benefit and matter for human kind, and greatly improved the development of economy and society. At the same time, however, it has also lead to the environment damage, which has affected the regional sustainable development. In this paper, we take the Luxi Coal Mine, Shandong Province as an example, based on the GIS, to study the effect on the sustainable development due to coal mining with the theory of ecological footprint. The research result show that coal mining inevitably affects the ecological footprint of coal mining area. In order to minimize the ecological deficit, measures shall be taken during coal mining period to reduce the environment damage by coal mining, adopting new reclamation method to protect the ecological producing land and avoiding cultivated land degraded.

  13. Ecological effects of soil contamination at Aberdeen Proving Ground, Maryland

    SciTech Connect

    Kuperman, R.G.; Dunn, C.P. (Argonne National Laboratory, IL (United States))

    1994-06-01

    Assessment of the ecological condition of contaminated soil was conducted in portions of the U.S. Army's Aberdeen Proving Ground, Maryland as part of an ecological risk assessment. This area is covered by open fields, woods and nontidal marshes. Chemicals disposed of in open burning pits included methylphosphonothioic acid, dichlorodiethyl sulfide, and titanium tetrachloride and sulfur trioxide/chlorosulfonic acid. Previous soil analysis showed extensive surface soil contamination with metals, nitrate, PCBs and pesticides. This assessment included characterizing soil biota, biologically-mediated processes in soil and aboveground biomass. Field surveys of the soil invertebrate communities showed significant reductions in the total abundance of animals, reductions in the abundance of several taxonomic and functional groups of soil invertebrates, and changes in the activity of epigeic arthropods in contaminated areas when compared with the local [open quotes]background[close quotes] area. Laboratory toxicity tests also demonstrated that microbial activity and success of egg hatching of ground beetle Harpalus pensylvanicus were reduced in contaminated soils. These results suggest that impacts to soil ecosystems should be explicitly considered in ecological risk assessment.

  14. Legacy effects in linked ecological-soil-geomorphic systems of drylands

    USGS Publications Warehouse

    Monger, Curtis; Sala, Osvaldo E.; Duniway, Michael C.; Goldfus, Haim; Meir, Isaac A.; Poch, Rosa M.; Throop, Heather L.; Vivoni, Enrique R.

    2015-01-01

    A legacy effect refers to the impacts that previous conditions have on current processes or properties. Legacies have been recognized by many disciplines, from physiology and ecology to anthropology and geology. Within the context of climatic change, ecological legacies in drylands (eg vegetative patterns) result from feedbacks between biotic, soil, and geomorphic processes that operate at multiple spatial and temporal scales. Legacy effects depend on (1) the magnitude of the original phenomenon, (2) the time since the occurrence of the phenomenon, and (3) the sensitivity of the ecological–soil–geomorphic system to change. Here we present a conceptual framework for legacy effects at short-term (days to months), medium-term (years to decades), and long-term (centuries to millennia) timescales, which reveals the ubiquity of such effects in drylands across research disciplines.

  15. Ecological modeling for the extrapolation of ecotoxicological effects measured during in situ assays in Gammarus.

    PubMed

    Coulaud, Romain; Geffard, Olivier; Coquillat, Amandine; Quéau, Hervé; Charles, Sandrine; Chaumot, Arnaud

    2014-06-01

    Evaluating the effects of chemical contamination on populations and ecological communities still constitutes a challenging necessity in environmental management. However, the toxic effects of contaminants are commonly measured by means of organism-level responses. Linking such effects measures with ecological models is a promising way to determine population-level impacts. In this way, population models are currently increasingly used in predictive risk assessment procedures, but their use in environmental diagnostic framework remains limited due to their lack of ecological realism. The present study with the crustacean Gammarus fossarum, a sentinel species in freshwater monitoring, combines a dual field and laboratory experimental approach with a population modeling framework. In this way, we developed an ecologically relevant periodic matrix population model for Gammarus. This model allowed us to capture the population dynamics in the field, and to understand the particular pattern of demographic sensitivities induced by Gammarus life-history phenology. The model we developed provided a robust population-level assessment of in situ-based effects measures recorded during a biomonitoring program on a French watershed impacted by past mining activities. Thus, our study illustrates the potential of population modeling when seeking to decipher the role of environmental toxic contamination in ecological perturbations. PMID:24805228

  16. Release of genetically engineered insects: a framework to identify potential ecological effects

    PubMed Central

    David, Aaron S; Kaser, Joe M; Morey, Amy C; Roth, Alexander M; Andow, David A

    2013-01-01

    Genetically engineered (GE) insects have the potential to radically change pest management worldwide. With recent approvals of GE insect releases, there is a need for a synthesized framework to evaluate their potential ecological and evolutionary effects. The effects may occur in two phases: a transitory phase when the focal population changes in density, and a steady state phase when it reaches a new, constant density. We review potential effects of a rapid change in insect density related to population outbreaks, biological control, invasive species, and other GE organisms to identify a comprehensive list of potential ecological and evolutionary effects of GE insect releases. We apply this framework to the Anopheles gambiae mosquito – a malaria vector being engineered to suppress the wild mosquito population – to identify effects that may occur during the transitory and steady state phases after release. Our methodology reveals many potential effects in each phase, perhaps most notably those dealing with immunity in the transitory phase, and with pathogen and vector evolution in the steady state phase. Importantly, this framework identifies knowledge gaps in mosquito ecology. Identifying effects in the transitory and steady state phases allows more rigorous identification of the potential ecological effects of GE insect release. PMID:24198955

  17. Effective discharge analysis of ecological processes in streams Martin W. Doyle,1

    E-print Network

    Stanley, Emily

    .1. Discharge Analysis in River Sciences [2] One of the most influential paradigms of fluvial geomorphologyEffective discharge analysis of ecological processes in streams Martin W. Doyle,1 Emily H. Stanley ecosystems. Here the analytical method of effective discharge from fluvial geomorphology is used to analyze

  18. THE YEAR IN ECOLOGY AND CONSERVATION BIOLOGY, 2009 Effects of Air Pollution on Ecosystems

    E-print Network

    Weathers, Kathleen C.

    THE YEAR IN ECOLOGY AND CONSERVATION BIOLOGY, 2009 Effects of Air Pollution on Ecosystems change, and invasive species as prime threats to biodiversity conservation. Although air pollution. In this synthesis, the state of scientific knowledge on the effects of air pollution on plants and animals

  19. POPULATION ECOLOGY Effects of Corn Plants and Corn Pollen on Monarch Butterfly

    E-print Network

    Hufbauer, Ruth A.

    POPULATION ECOLOGY Effects of Corn Plants and Corn Pollen on Monarch Butterfly (Lepidoptera of exposure of their offspring to natural and artiÞcial toxins. Pollen from Bt-corn hybrids represents a novel. The effect of corn plant proximity and corn pollen presence on the oviposition behavior of the monarch

  20. Effects of the Trematode Uvulifer ambloplitis on Juvenile Bluegill Sunfish, Lepomis macrochirus: Ecological Implications

    E-print Network

    Wisenden, Brian D.

    Effects of the Trematode Uvulifer ambloplitis on Juvenile Bluegill Sunfish, Lepomis macrochirus the following article: Effects of the Trematode Uvulifer ambloplitis on Juvenile Bluegill Sunfish, Lepomis macrochirus: Ecological Implications A. Dennis Lemly; Gerald W. Esch The Journal of Parasitology, Vol. 70, No

  1. Pantothenol protects rats against some deleterious effects of gamma radiation.

    PubMed

    Slyshenkov, V S; Omelyanchik, S N; Moiseenok, A G; Trebukhina, R V; Wojtczak, L

    1998-04-01

    Rats were exposed to gamma radiation from a 60Co source, receiving 0.25 Gy at weekly intervals. During 2 d before each irradiation, the animals received daily intragastric doses of 26 mg pantothenol or 15 mg beta-carotene per kg body weight. One hour after the third irradiation session, the animals were killed and their livers were analyzed. In animals not supplied with pantothenol, the irradiation resulted in a significant decrease of total liver lipids and a 50% decrease in phospholipids. Liver cholesterol was decreased by about 20%. Irradiation produced lipid peroxidation as expressed by doubling of the amounts of conjugated dienes and ketone dienes and of thiobarbituric acid reactive compounds. The amount of CoA in liver was decreased by 24% and that of reduced glutathione by 40%. The NAD+/NADH ratio was increased by 60% and the activity of NADP-dependent malate dehydrogenase (decarboxylating) was decreased by 26%. The amount of pantothenic acid and its derivatives (expressed as pantolactone-generating compounds) in blood decreased by about 80%. In rats to which pantothenol was administered, the content of pantothenic acid in blood was tripled compared to nonirradiated (control) rats, and all the biochemical parameters measured in liver were the same as in nonirradiated animals. PMID:9607598

  2. Deleterious Effects of Psychotherapy and Counseling in the Schools

    ERIC Educational Resources Information Center

    Nicholson, Heather; Foote, Catherine; Grigerick, Sarah

    2009-01-01

    Providing individual and group counseling has become an identified role for school psychologists working in the school setting. There is an extensive research base that highlights positive outcomes and supports the use of a variety of counseling methods when working with children and adolescents. However, there may exist a host of other outcomes,…

  3. RNA chaperones buffer deleterious mutations in E. coli

    PubMed Central

    Rudan, Marina; Schneider, Dominique; Warnecke, Tobias; Krisko, Anita

    2015-01-01

    Both proteins and RNAs can misfold into non-functional conformations. Protein chaperones promote native folding of nascent polypeptides and refolding of misfolded species, thereby buffering mutations that compromise protein structure and function. Here, we show that RNA chaperones can also act as mutation buffers that enhance organismal fitness. Using competition assays, we demonstrate that overexpression of select RNA chaperones, including three DEAD box RNA helicases (DBRHs) (CsdA, SrmB, RhlB) and the cold shock protein CspA, improves fitness of two independently evolved Escherichia coli mutator strains that have accumulated deleterious mutations during short- and long-term laboratory evolution. We identify strain-specific mutations that are deleterious and subject to buffering when introduced individually into the ancestral genotype. For DBRHs, we show that buffering requires helicase activity, implicating RNA structural remodelling in the buffering process. Our results suggest that RNA chaperones might play a fundamental role in RNA evolution and evolvability. DOI: http://dx.doi.org/10.7554/eLife.04745.001 PMID:25806682

  4. EPA/OFFICE OF RESEARCH AND DEVELOPMENT'S NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY/WESTERN ECOLOGY DIVISION INTERNET SITE

    EPA Science Inventory

    The Western Ecology Division (WED) is one of four ecological effects divisions of the National Health and Environmental Effects Research Laboratory. The four divisions are distributed bio-geographically. WED's mission is 1) to provide EPA with national scientific leadership for t...

  5. Ecological effects of invasive alien insects Marc Kenis Marie-Anne Auger-Rozenberg Alain Roques Laura Timms

    E-print Network

    Schweik, Charles M.

    Ecological effects of invasive alien insects Marc Kenis Ã? Marie-Anne Auger-Rozenberg Ã? Alain Roques identified 403 primary research publications that investigated the ecological effects of invasive alien, preda- tion or parasitism. Alien species may also affect native species and communities through more com

  6. Allelic Expression of Deleterious Protein-Coding Variants across Human Tissues

    PubMed Central

    Kukurba, Kimberly R.; Zhang, Rui; Li, Xin; Smith, Kevin S.; Knowles, David A.; How Tan, Meng; Piskol, Robert; Lek, Monkol; Snyder, Michael; MacArthur, Daniel G.; Li, Jin Billy; Montgomery, Stephen B.

    2014-01-01

    Personal exome and genome sequencing provides access to loss-of-function and rare deleterious alleles whose interpretation is expected to provide insight into individual disease burden. However, for each allele, accurate interpretation of its effect will depend on both its penetrance and the trait's expressivity. In this regard, an important factor that can modify the effect of a pathogenic coding allele is its level of expression; a factor which itself characteristically changes across tissues. To better inform the degree to which pathogenic alleles can be modified by expression level across multiple tissues, we have conducted exome, RNA and deep, targeted allele-specific expression (ASE) sequencing in ten tissues obtained from a single individual. By combining such data, we report the impact of rare and common loss-of-function variants on allelic expression exposing stronger allelic bias for rare stop-gain variants and informing the extent to which rare deleterious coding alleles are consistently expressed across tissues. This study demonstrates the potential importance of transcriptome data to the interpretation of pathogenic protein-coding variants. PMID:24786518

  7. GLOBAL CHANGE AND CONSERVATION ECOLOGY Effects of an increase in summer precipitation on leaf, soil,

    E-print Network

    Bentley, Lisa Patrick

    Á Ecosystem fluxes Á Precipitation manipulation Introduction Changes in the global climate systemGLOBAL CHANGE AND CONSERVATION ECOLOGY Effects of an increase in summer precipitation on leaf, soil, and ecosystem fluxes of CO2 and H2O in a sotol grassland in Big Bend National Park, Texas Lisa Patrick Æ Jessica

  8. Uncovering the diversification history of marine tetrapods: ecology influences the effect of geological sampling biases

    E-print Network

    Cambridge, University of

    , and multiple regression models. These indicate that shallow marine diversity was driven by changes to `escape' from periodic extinctions driven by major marine regressions, which affected shallow marine taxaUncovering the diversification history of marine tetrapods: ecology influences the effect

  9. Assessing the Effectiveness of a Computer Simulation for Teaching Ecological Experimental Design

    ERIC Educational Resources Information Center

    Stafford, Richard; Goodenough, Anne E.; Davies, Mark S.

    2010-01-01

    Designing manipulative ecological experiments is a complex and time-consuming process that is problematic to teach in traditional undergraduate classes. This study investigates the effectiveness of using a computer simulation--the Virtual Rocky Shore (VRS)--to facilitate rapid, student-centred learning of experimental design. We gave a series of…

  10. Salt marsh geomorphology: Physical and ecological effects on landform Keywords: salt marsh geomorphology; AGU Chapman Conference

    E-print Network

    Fagherazzi, Sergio

    Editorial Salt marsh geomorphology: Physical and ecological effects on landform Keywords: salt marsh geomorphology; AGU Chapman Conference Evidence that the three-dimensional structure of salt marsh, and the ratio of marsh edge:marsh interior have all been shown to affect the distribution and density of salt

  11. ECOSYSTEM ECOLOGY The effects of tree establishment on water and salt dynamics

    E-print Network

    Nacional de San Luis, Universidad

    ECOSYSTEM ECOLOGY The effects of tree establishment on water and salt dynamics in naturally salt an imprint on salt accumulation and distribution patterns. We explored how the conversion of native grasslands to oak plantations affected the abundance and distribution of salts on soils and groundwater

  12. GLOBAL CHANGE ECOLOGY -ORIGINAL RESEARCH Ecosystems effects 25 years after Chernobyl: pollinators,

    E-print Network

    Mousseau, Timothy A.

    GLOBAL CHANGE ECOLOGY - ORIGINAL RESEARCH Ecosystems effects 25 years after Chernobyl: pollinators, pollinator abundance, fruit abundance and abundance of frugivores. Given that the Chernobyl disaster happened of a suppressed pollinator community on ecosystem functioning. Keywords Chernobyl Á Ecosystem functioning Á Fruits

  13. GLOBAL CHANGE ECOLOGY -ORIGINAL RESEARCH Ecosystems effects 25 years after Chernobyl: pollinators,

    E-print Network

    Mousseau, Timothy A.

    GLOBAL CHANGE ECOLOGY - ORIGINAL RESEARCH Ecosystems effects 25 years after Chernobyl: pollinators, fruit abundance and abundance of frugivores. Given that the Chernobyl disaster happened 25 years ago of a suppressed pollinator community on ecosystem functioning. Keywords Chernobyl Á Ecosystem functioning Á Fruits

  14. Effects of biological pit additives on microbial ecology of stored pig manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of biological pit additives on microbial ecology in stored pig manure were investigated using a dynamic manure storage system, which allowed for continual addition of swine feces and urine. After 13 weeks of manure collection and storage, four treatments were added to tanks (900 L capaci...

  15. International Association for Ecology Prey Nutritional Quality and the Effectiveness of Chemical Defenses against Tropical Reef

    E-print Network

    Duffy, J. Emmett

    International Association for Ecology Prey Nutritional Quality and the Effectiveness of Chemical. http://www.jstor.org #12;Oecologia (1992) 90:333-339 ~ZZ Z ? Oecologia Prey nutritional quality- vertebrates produce both secondary chemicals and min- eral or fibrous skeletal materials that can reduce

  16. Effects of Conceptual Change Text Based Instruction on Ecology, Attitudes toward Biology and Environment

    ERIC Educational Resources Information Center

    Çetin, Gülcan; Ertepinar, Hamide; Geban, Ömer

    2015-01-01

    The purpose of this study is to investigate the effects of the conceptual change text based instruction on ninth grade students' understanding of ecological concepts, and attitudes toward biology and environment. Participants were 82 ninth grade students in a public high school in the Northwestern Turkey. A treatment was employed over a…

  17. Impact: Toward a Framework for Understanding the Ecological Effects of Invaders

    Microsoft Academic Search

    I. M. Parker; D. Simberloff; W. M. Lonsdale; K. Goodell; M. Wonham; P. M. Kareiva; M. H. Williamson; B. Von Holle; P. B. Moyle; J. E. Byers; L. Goldwasser

    1999-01-01

    Although ecologists commonly talk about the impacts of nonindigenous species, little formal attention has been given to defining what we mean by impact, or connecting ecological theory with particular measures of impact. The resulting lack of generalizations regarding invasion impacts is more than an academic problem; we need to be able to distinguish invaders with minor effects from those with

  18. Pleistocene and ecological effects on continental-scale genetic differentiation in the bobcat (Lynx rufus)

    E-print Network

    Bronikowski, Anne

    of genetic structure. Keywords: bobcat, landscape genetics, Lynx rufus, phylogeography, Pleistocene, suturePleistocene and ecological effects on continental-scale genetic differentiation in the bobcat (Lynx rufus) DAWN M. REDING,* ANNE M. BRONIKOWSKI,* WARREN E. JOHNSON and WILLIAM R. CLARK* *Department

  19. BOOK REVIEW OF "ECOLOGICAL EFFECTS OF ROADS"

    EPA Science Inventory

    Throughout the world, roads have become a permanent part of our environment. The ecological effects of roads and traffic are as consequential as other topical issues such as losses in biological diversity and damage by exotic and invasive species. However, this issue has usuall...

  20. Variable ecological effects of hurricanes: The importance of seasonal timing for survival

    E-print Network

    Losos, Jonathan B.

    Variable ecological effects of hurricanes: The importance of seasonal timing for survival University, St. Louis, MO 63130 Contributed by Thomas W. Schoener, October 24, 2003 Two recent hurricanes populations inhabiting exactly the same islands. The hurricanes differed in two ways: one struck during

  1. Ecological Effects of Micropterus Introductions: the Dark Side of Black Bass

    E-print Network

    Jackson, Don

    Micropterus salmoides and smallmouth bass M. dolomieu are two widely introduced species of fish prized1 Ecological Effects of Micropterus Introductions: the Dark Side of Black Bass DONALD A. JACKSON environments, angling for bass, in particular largemouth bass Micropterus salmoides and smallmouth bass M

  2. Research Plan for Study of Biological and Ecological Effects of the Solar Power Satellite Transmission System

    NASA Technical Reports Server (NTRS)

    Newsom, B. D.

    1978-01-01

    A programmatic research plan for a three year study is presented to generate knowledge on effects of the continuous wave 2.45 GHz microwave power transmission that the Solar Power Satellite might have on biological and ecological elements, within and around the rectenna receiving site.

  3. Persistent ecological effects of a salmon-derived nutrient pulse on stream invertebrate communities

    E-print Network

    Reynolds, John D.

    Persistent ecological effects of a salmon-derived nutrient pulse on stream invertebrate communities salmon density, stream habitats, and the abundance and diversity of stream invertebrates ten months after salmon spawning, across 21 streams in central British Columbia, Canada. Total invertebrate abundance

  4. Wildfire-contingent effects of fuel treatments can promote ecological resilience in seasonally dry conifer forests

    E-print Network

    North, Malcolm

    ARTICLE Wildfire-contingent effects of fuel treatments can promote ecological resilience suppression has made many seasonally dry conifer forests more susceptible to high-severity wildfires, which resilience to recurring wildfire events. To address this question, we established 664 plots across 12

  5. PHYSIOLOGICAL AND CHEMICAL ECOLOGY Effects of Paper Birch Condensed Tannin on Whitemarked Tussock

    E-print Network

    PHYSIOLOGICAL AND CHEMICAL ECOLOGY Effects of Paper Birch Condensed Tannin on Whitemarked Tussock Marshall, condensed tannin on larval performance of the whitemarked tussock moth, Orgyia leucostigma (J. E diets: control (no condensed tannin), moderate condensed tannin (8.8% dry mass), and high condensed

  6. Ecological Modelling 153 (2002) 131142 Temperature sensitivity of soil respiration and its effects on

    E-print Network

    Wu, Jianguo "Jingle"

    Ecological Modelling 153 (2002) 131­142 Temperature sensitivity of soil respiration and its effects of the nonlinearity in temperature sensitivity of soil respiration, several commonly used ecosystem models produce substantially different estimates of soil respiration with the same or similar model input. In this paper we

  7. Combined effects of muscular dystrophy, ecological stress, and selenium on blood antioxidant status in broiler chickens.

    PubMed

    Georgieva, Nedyalka V; Stoyanchev, Krasimir; Bozakova, Nadia; Jotova, Ivanka

    2011-09-01

    The results obtained in this study demonstrated that experimentally induced alimentary muscular dystrophy (MD) in Cobb 500 broiler chickens resulted in increased plasma concentrations of malondialdehyde (MDA), deviations in activities of erythrocyte antioxidant enzymes Cu,Zn-SOD (decrease), and CAT (increase) as well as reduction in plasma concentrations of trace elements Cu, Zn, and Se in affected birds. These data evidenced the presence of oxidative stress in birds with MD, reared both under conditions of ecological comfort and ecological stress. The increased MDA and ??? levels and the reduced Cu,Zn-SOD, Cu, Zn, and Se concentrations in healthy chickens reared under unfavorable microclimatic conditions such as higher air temperature and humidity, higher ammonia concentrations, and lower light intensity were indicative about an induced ecological stress. After the 10-day oral treatment with a selenium-containing preparation, the levels of MDA, Cu,Zn-SOD, CAT, Cu, Zn, and Se attained their normal values in chickens with MD, reared under ecologically comfortable conditions. According to our results, ecological stress was shown to exert independently a significant adverse effect upon the levels of the studied parameters and possibly to be a cause for their slower and not complete normalization despite the selenium therapy in experimental broiler chickens. PMID:20668960

  8. Ecological significance of residual exposures and effects from the Exxon Valdez oil spill.

    PubMed

    Harwell, Mark A; Gentile, John H

    2006-07-01

    An ecological significance framework is used to assess the ecological condition of Prince William Sound (PWS), Alaska, USA, in order to address the current management question: 17 y following the Exxon Valdez oil spill (EVOS), are there any remaining and continuing ecologically significant exposures or effects on the PWS ecosystem caused by EVOS? We examined the extensive scientific literature funded by the Exxon Valdez Trustees or by ExxonMobil to assess exposures and effects from EVOS. Criteria to assess ecological significance include whether a change in a valued ecosystem component (VEC) is sufficient to affect the structure, function, and/or health of the system and whether such a change exceeds natural variability. The EVOS occurred on 24 March 1989, releasing over 250,000 barrels of crude oil into PWS. Because PWS is highly dynamic, the residual oil was largely eliminated in the first few years, and now only widely dispersed, highly weathered, or isolated small pockets of residual contamination remain. Many other sources of polycyclic aromatic hydrocarbons (PAHs) exist in PWS from past or present human activities or natural oil seeps. Multiple-lines-of-evidence analyses indicate that residual PAHs from EVOS no longer represent an ecologically significant exposure risk to PWS. To assess the ecological significance of any residual effects from EVOS, we examined the literature on more than 20 VECs, including primary producers, filter feeders, fish and bird primary consumers, fish and bird top predators, a bird scavenger, mammalian primary consumers and top predators, biotic communities, ecosystem-level properties of trophodynamics and biogeochemical processes, and landscape-level properties of habitat mosaic and wilderness quality. None of these has any ecologically significant effects that are detectable at present, with the exception of 1 pod of orcas and possibly 1 subpopulation of sea otters; however, in both those cases, PWS-wide populations appear to have fully recovered. Many other stressors continue to affect PWS adversely, including climate and oceanographic variability, increased tourism and shipping, invasive species, the 1964 earthquake, and overexploitation of marine resources, with associated cascading effects on populations of PWS fish and predators. We conclude that the PWS ecosystem has now effectively recovered from EVOS. PMID:16869437

  9. Low Impact of Germline Transposition on the Rate of Mildly Deleterious Mutation in Caenorhabditis elegans

    PubMed Central

    Bégin, Mattieu; Schoen, Daniel J.

    2006-01-01

    Little is known about the role of transposable element (TE) insertion in the production of mutations with mild effects on fitness, the class of mutations thought to be central to the evolution of many basic features of natural populations. We propagated mutation-accumulation (MA) lines of two RNAi-deficient strains of Caenorhabditis elegans that exhibit germline transposition. We show here that the impact of TE activity was to raise the level of mildly deleterious mutation by 2- to 8.5-fold, as estimated from fecundity, longevity, and body length measurements, compared to that observed in a parallel MA experiment with a control strain characterized by a lack of germline transposition. Despite this increase, the rate of mildly deleterious mutation was between one and two orders of magnitude lower than the rate of TE accumulation, which was approximately two new insertions per genome per generation. This study suggests that high rates of TE activity do not necessarily translate into high rates of detectable nonlethal mutation. PMID:17057249

  10. Defending Ecology

    NSDL National Science Digital Library

    Brian Margolis

    2000-02-01

    Incorporating the issue of non-native species into science curricula is an effective way to protect our deteriorating environment while teaching students fundamental principles of ecology. In addition, the ubiquitous nature of the problem allows students

  11. Effects of silvicultural activity on ecological processes in floodplain forests of the southern United States: a review of existing reports

    Microsoft Academic Search

    B. G. Lockaby; J. A. Stanturf; M. G. Messina

    1997-01-01

    Activities associated with timber harvesting have occurred within floodplain forests in the southern United States for nearly two hundred years. However, it is only in the last ten years that any information has become available about the effects of harvesting on the ecological functions of this valuable resource. Hydrology is the driving influence behind all ecological processes in floodplains, and

  12. Warfare Ecology

    NSDL National Science Digital Library

    Gary E. Machlis (University of Idaho; )

    2008-09-01

    Among human activities causing ecological change, war is both intensive and far-reaching. Yet environmental research related to warfare is limited in depth and fragmented by discipline. Here we (1) outline a field of study called "warfare ecology," (2) provide a taxonomy of warfare useful for organizing the field, (3) review empirical studies, and (4) propose research directions and policy implications that emerge from the ecological study of warfare. Warfare ecology extends to the three stages of warfare - preparations, war, and postwar activities - and treats biophysical and socioeconomic systems as coupled systems. A review of empirical studies suggests complex relationships between warfare and ecosystem change. Research needs include the development of theory and methods for examining the cascading effects of warfare on specific ecosystems. Policy implications include greater incorporation of ecological science into military planning and improved rehabilitation of postwar ecosystem services, leading to increased peace and security.

  13. Ecological and physiological/toxicological effects of petroleum on aquatic birds

    USGS Publications Warehouse

    Stickel, L.F.; Dieter, M.P.; Tait, H.D.; Hall, C.

    1979-01-01

    The physiological and ecological effects of oil on waterbirds were examined in a series of laboratory and field experiments. Chemical methodology was developed in support of these studies. Research conducted from 1 July 1975 to 30 September 1978 by the US Fish and Wildlife Service about the effects of petroleum on aquatic birds is summarized. The following assessments were made: effects of oiling on hatchability of eggs; effects of oil ingestion on physiological condition and survival of birds; effects of oil ingestion on reproduction in birds; accumulation and loss of oil by birds; and development of analytical methods for identification and quantification of oil breakdown products in tissues and eggs of ducks.

  14. Ecological effects, transport, and fate of mercury: a general review

    Microsoft Academic Search

    Dean W. Boening

    2000-01-01

    Mercury at low concentrations represents a major hazard to microorganisms. Inorganic mercury has been reported to produce harmful effects at 5 ?g\\/l in a culture medium. Organomercury compounds can exert the same effect at concentrations 10 times lower than this. The organic forms of mercury are generally more toxic to aquatic organisms and birds than the inorganic forms. Aquatic plants

  15. Use of QSARs in international decision-making frameworks to predict ecologic effects and environmental fate of chemical substances.

    PubMed Central

    Cronin, Mark T D; Walker, John D; Jaworska, Joanna S; Comber, Michael H I; Watts, Christopher D; Worth, Andrew P

    2003-01-01

    This article is a review of the use, by regulatory agencies and authorities, of quantitative structure-activity relationships (QSARs) to predict ecologic effects and environmental fate of chemicals. For many years, the U.S. Environmental Protection Agency has been the most prominent regulatory agency using QSARs to predict the ecologic effects and environmental fate of chemicals. However, as increasing numbers of standard QSAR methods are developed and validated to predict ecologic effects and environmental fate of chemicals, it is anticipated that more regulatory agencies and authorities will find them to be acceptable alternatives to chemical testing. PMID:12896861

  16. The effect of dam operation on the hydrology and ecology of a tropical riverine floodplain system

    NASA Astrophysics Data System (ADS)

    Köck, Florian; Blaser, Wilma J.; Shanungu, Griffin

    2014-05-01

    Worldwide, dam operation has been changing the flow regimes of many rivers with significant impact on riverine ecosystems. At the same time, dam management itself provides the key to better control the specifics of this hydraulic alteration and hence to mitigate negative effects of river regulation. In our study we aimed at substantiating the ecological basis for an adapted dam management for the case of a seasonally inundated riverine floodplain system in Zambia, Southern Africa. We quantified dam-induced alterations and investigated the relationship between an altered flow regime and altered ecological conditions in the floodplain. For this, we adapted the "Indicators of Hydraulic Alterations" to seasonal tropical river systems and used them to analyze both the pristine and the regulated hydrological regime, namely the inflow to the floodplain, water level in the floodplain and modeled flooded area in the ecologically most valuable part of the floodplain. We checked the reliability of the adapted indicators and demonstrated how dam operation reduces the correlation between them, making it undesirable to further reduce the number of indicators. Using the limited ecological data available we then identified critical hydrological situations that put at risk the functioning of the dam-impacted, flood-dependent grazing ecosystem and investigated the potential of an adapted dam operation for managing these situations. We formulated targets for an adapted dam operation and assessed the potential and the limitations for achieving these targets, where possible giving water management and monitoring recommendations.

  17. Environmental and Ontogenetic Effects on Intraspecific Trait Variation of a Macrophyte Species across Five Ecological Scales

    PubMed Central

    Zhong, Jiayou; Cao, Te; Ni, Leyi; Xie, Ping

    2013-01-01

    Although functional trait variability is increasingly used in community ecology, the scale- and size-dependent aspects of trait variation are usually disregarded. Here we quantified the spatial structure of shoot height, branch length, root/shoot ratio and leaf number in a macrophyte species Potamogeton maackianus, and then disentangled the environmental and ontogenetic effects on these traits. Using a hierarchical nested design, we measured the four traits from 681 individuals across five ecological scales: lake, transect, depth stratus, quadrat and individual. A notable high trait variation (coefficient variation: 48–112%) was observed within species. These traits differed in the spatial structure, depending on environmental factors of different scales. Shoot height and branch length were most responsive to lake, transect and depth stratus scales, while root/shoot ratio and leaf number to quadrat and individual scales. The trait variations caused by environment are nearly three times higher than that caused by ontogeny, with ontogenetic variance ranging from 21% (leaf number) to 33% (branch length) of total variance. Remarkably, these traits showed non-negligible ontogenetic variation (0–60%) in each ecological scale, and significant shifts in allometric trajectories at lake and depth stratus scales. Our results highlight that environmental filtering processes can sort individuals within species with traits values adaptive to environmental changes and ontogenetic variation of functional traits was non-negligible across the five ecological scales. PMID:23626856

  18. THE EFFECTS OF PATCH SHAPE ON INDIGO BUNTINGS: EVIDENCE FOR AN ECOLOGICAL TRAP

    SciTech Connect

    AIMEE J. WELDON; NICK M. HADDAD

    2005-01-01

    Weldon, Aimee, J., and Nick M. Haddad. 2005. The effect of patch shape on indigo buntings: Evidence for an ecological trap. Ecology 86(6):1422-1431. Abstract. Habitat loss and fragmentation have led to a widespread increase in the proportion of edge habitat in the landscape. Disturbance-dependent bird species are widely assumed to benefit from these edges. However, anthropogenic edges may concentrate nest predators while retaining habitat cues that birds use to select breeding habitat. This may lead birds to mistakenly select dangerous habitat?a phenomenon known as an ??ecological trap.?? We experimentally demonstrated how habitat shape, and thus amount of edge, can adversely affect nest site selection and reproductive success of a disturbance-dependent bird species, the Indigo Bunting (Passerina cyanea). We did so within a landscape-scale experiment composed of equal-area habitat patches that differed in their amount of edge. Indigo Buntings preferentially selected edgy patches, which contained 50% more edge than more compact rectangular patches. Further, buntings fledged significantly fewer young per pair in edgy patches than in rectangular patches. These results provide the first experimental evidence that edges can function as ecological traps.

  19. Endocrine dysfunction in sepsis: a beneficial or deleterious host response?

    PubMed

    Gheorghi??, Valeriu; Barbu, Alina Elena; Gheorghiu, Monica Livia; C?runtu, Florin Alexandru

    2015-03-01

    Sepsis is a systemic, deleterious inflammatory host response triggered by an infective agent leading to severe sepsis, septic shock and multi-organ failure. The host response to infection involves a complex, organized and coherent interaction between immune, autonomic, neuroendocrine and behavioral systems. Recent data have confirmed that disturbances of the autonomic nervous and neuroendocrine systems could contribute to sepsis-induced organ dysfunction. Through this review, we aimed to summarize the current knowledge about the endocrine dysfunction as response to sepsis, specifically addressed to vasopressin, copeptin, cortisol, insulin and leptin. We searched the following readily accessible, clinically relevant databases: PubMed, UpToDate, BioMed Central. The immune system could be regarded as a "diffuse sensory organ" that signals the presence of pathogens to the brain through different pathways, such as the vagus nerve, endothelial activation/dysfunction, cytokines and neurotoxic mediators and the circumventricular organs, especially the neurohypophysis. The hormonal profile changes substantially as a consequence of inflammatory mediators and microorganism products leading to inappropriately low levels of vasopressin, sick euthyroid syndrome, reduced adrenal responsiveness to ACTH, insulin resistance, hyperglycemia as well as hyperleptinemia. In conclusion, clinical diagnosis of this "pan-endocrine illness" is frequently challenging due to the many limiting factors. The most important benefits of endocrine markers in the management of sepsis may be reflected by their potential to be used as biomarkers in different scoring systems to estimate the severity of the disease and the risk of death. PMID:25763364

  20. Endocrine dysfunction in sepsis: a beneficial or deleterious host response?

    PubMed Central

    Gheorghi??, Valeriu; Barbu, Alina Elena; Gheorghiu, Monica Livia; C?runtu, Florin Alexandru

    2015-01-01

    Sepsis is a systemic, deleterious inflammatory host response triggered by an infective agent leading to severe sepsis, septic shock and multi-organ failure. The host response to infection involves a complex, organized and coherent interaction between immune, autonomic, neuroendocrine and behavioral systems. Recent data have confirmed that disturbances of the autonomic nervous and neuroendocrine systems could contribute to sepsis-induced organ dysfunction. Through this review, we aimed to summarize the current knowledge about the endocrine dysfunction as response to sepsis, specifically addressed to vasopressin, copeptin, cortisol, insulin and leptin. We searched the following readily accessible, clinically relevant databases: PubMed, UpToDate, BioMed Central. The immune system could be regarded as a “diffuse sensory organ” that signals the presence of pathogens to the brain through different pathways, such as the vagus nerve, endothelial activation/dysfunction, cytokines and neurotoxic mediators and the circumventricular organs, especially the neurohypophysis. The hormonal profile changes substantially as a consequence of inflammatory mediators and microorganism products leading to inappropriately low levels of vasopressin, sick euthyroid syndrome, reduced adrenal responsiveness to ACTH, insulin resistance, hyperglycemia as well as hyperleptinemia. In conclusion, clinical diagnosis of this “pan-endocrine illness” is frequently challenging due to the many limiting factors. The most important benefits of endocrine markers in the management of sepsis may be reflected by their potential to be used as biomarkers in different scoring systems to estimate the severity of the disease and the risk of death. PMID:25763364

  1. Community responses to contaminants: using basic ecological principles to predict ecotoxicological effects.

    PubMed

    Clements, William H; Rohr, Jason R

    2009-09-01

    Community ecotoxicology is defined as the study of the effects of contaminants on patterns of species abundance, diversity, community composition, and species interactions. Recent discoveries that species diversity is positively associated with ecosystem stability, recovery, and services have made a community-level perspective on ecotoxicology more important than ever. Community ecotoxicology must explicitly consider both present and impending global change and shift from a purely descriptive to a more predictive science. Greater consideration of the ecological factors and threshold responses that determine community resistance and resilience should improve our ability to predict how and when communities will respond to, and recover from, xenobiotics. A better understanding of pollution-induced community tolerance, and of the costs of this tolerance, should facilitate identifying contaminant-impacted communities, thus forecasting the ecological consequences of contaminant exposure and determining the restoration effectiveness. Given the vast complexity of community ecotoxicology, simplifying assumptions, such as the possibility that the approximately 100,000 registered chemicals could be reduced to a more manageable number of contaminant classes with similar modes of action, must be identified and validated. In addition to providing a framework for predicting contaminant fate and effects, food-web ecology can help to identify communities that are sensitive to contaminants, contaminants that are particularly insidious to communities, and species that are crucial for transmitting adverse effects across trophic levels. Integration of basic ecological principles into the design and implementation of ecotoxicological research is essential for predicting contaminant effects within the context of rapidly changing, global environmental conditions. PMID:19358627

  2. Fixation of a deleterious allele at one of two "duplicate" loci by mutation pressure and random drift.

    PubMed Central

    Kimura, M; King, J L

    1979-01-01

    We consider a diploid population and assume two gene loci with two alleles each, A and a at one locus and B and b at the second locus. Mutation from wild-type alleles A and B to deleterious alleles a and b occurs with mutation rates va and vb, respectively. We assume that alleles are completely recessive and that only the double recessive genotype aabb shows a deleterious effect with relative fitness 1-epsilon. Then, it can be shown that if va greater than vb mutant a becomes fixed in the population by mutation pressure and a mutation-selection balance is ultimately attained with respect to the B/b locus alone. The main aim of this paper is to investigate the situation in which va = vb exactly. In this case a neutral equilibrium is attained and either locus can drift to fixation for the mutant allele. Diffusion models are developed to treat the stochastic process involved whereby the deleterious mutant eventually becomes fixed in one of the two duplicated loci by random sampling drift in finite populations. In particular, the equation for the average time until fixation of mutant a or b is derived, and this is solved numerically for some combinations of parameters 4Nev and 4Ne epsilon, where v is the mutation rate (va = vb = v) and Ne is the effective size of the population. Monte Carlo experiments have been performed (using a device termed "pseudo sampling variable") to supplement the numerical analysis. PMID:288072

  3. The effects of an experimental chlorate product on the microbial ecology in Gallus gallus var. domesticus.

    E-print Network

    McReynolds, Jackson Lee

    2004-09-30

    THE EFFECTS OF AN EXPERIMENTAL CHLORATE PRODUCT ON THE MICROBIAL ECOLOGY IN GALLUS GALLUS VAR. DOMESTICUS A Dissertation by JACKSON LEE MCREYNOLDS Submitted to the Office of Graduate Studies of Texas A&M University.... DOMESTICUS A Dissertation by JACKSON LEE MCREYNOLDS Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Approved as to style and content by...

  4. Evaluating the effects of embodied energy in international trade on ecological footprint in China

    Microsoft Academic Search

    Li Hong; Zhang Pei Dong; He Chunyu; Wang Gang

    2007-01-01

    Based on sub-sectoral level of economy and detailed traded items, embodied energy (EE) in international trade flow in China is estimated during 1996–2004, and the effects of EE on sustainability are quantified by using one of the most popular indicators—Ecological footprint (EF). A framework of EF method, which is more relevant to realism of specific country, is proposed in this

  5. Sustainable ecological development reducing negative effects of road maintenance salts

    Microsoft Academic Search

    Pranas Baltrenas; Agne Kazlauskiene

    2009-01-01

    To ensure traffic safety in winter, large amounts of technical salts (chlorides) are applied on roads. De?icing salts directly or indirectly contaminate the road environment and have a negative effect on the components of road environment. The analysis of the situation raises a question: how to ensure traffic safety in wintertime applying salts and achieve sustainable development. The article presents

  6. EFFECT OF DIFFERENT POLLUTANTS ON ECOLOGICALLY IMPORTANT POLYCHAETE WORMS

    EPA Science Inventory

    The procedures for culturing marine polychaetous annelids from egg to egg under laboratory conditions were described. A manual was prepared detailing the procedures used in culturing 12 species of polychaetes. The effects of heavy metals and the water soluble fractions of petrole...

  7. ECOLOGICAL EFFECTS OF EXPERIMENTAL ACIDIFICATION ON A STREAM ECOSYSTEM

    EPA Science Inventory

    The report describes the quantitative effects of experimentally increasing the acidity of a mountain stream ecosystem to pH levels frequently found in incident precipitation in the northeastern United States. The field experiment was designed to test the hypothesis that such acid...

  8. Flow effects on benthic stream invertebrates and ecological processes

    Microsoft Academic Search

    Maja Koprivsek; Mitja Brilly

    2010-01-01

    Flow is the main abiotic factor in the streams. Flow affects the organisms in many direct and indirect ways. The organisms are directly affected by various hydrodynamic forces and mass transfer processes like drag forces, drift, shear stress, food and gases supply and washing metabolites away. Indirect effects on the organisms are determining and distribution of the particle size and

  9. Appendix 30 Fire Effects on Key Ecological Processes in Forested

    E-print Network

    paragraphs on fire effects on forest succession are from Stickney (1982) Forest Succession ...the severity survivors derive from plants already established at the time of disturbance, it is possible...to determine becomes more favorable as a site for germination and establishment of colonizer plants. Increases

  10. Looking beneath the surface to determine what makes DNA damage deleterious.

    PubMed

    Greenberg, Marc M

    2014-08-01

    Apurinic/apyrimidinic and oxidized abasic sites are chemically reactive DNA lesions that are produced by a variety of damaging agents. The effects of these molecules that lack a Watson-Crick base on polymerase enzymes are well documented. More recently, multiple consequences of the electrophilic nature of abasic lesions have been revealed. Members of this family of DNA lesions have been shown to inactivate repair enzymes and undergo spontaneous transformation into more deleterious forms of damage. Abasic site reactivity provides insight into the chemical basis for the cytotoxicity of DNA damaging agents that produce them and are valuable examples of how looking beneath the surface of seemingly simple molecules can reveal biologically relevant chemical complexity. PMID:24762292

  11. EVALUATION OF METHODS FOR DETECTING ECOLOGICAL EFFECTS FROM GENETICALLY ENGINEERED MICROORGANISMS AND PEST CONTROL AGENTS IN TERRESTRIAL SYSTEMS

    EPA Science Inventory

    This report summarizes and evaluates research from several laboratories that deals with the detection of ecological effects induced through exposure of microbes or plants to genetically engineered microorganisms (GEMS) and microbial pest control agents (MPCAS) . The development o...

  12. The charcoal effect in Boreal forests: mechanisms and ecological consequences

    Microsoft Academic Search

    D. A. Wardle; O. Zackrisson; M.-C. Nilsson

    1998-01-01

    Wildfire is the principal disturbance regime in northern Boreal forests, where it has important rejuvenating effects on soil\\u000a properties and encourages tree seedling regeneration and growth. One possible agent of this rejuvenation is fire-produced\\u000a charcoal, which adsorbs secondary metabolites such as humus phenolics produced by ericaceous vegetation in the absence of\\u000a fire, which retard nutrient cycling and tree seedling growth.

  13. Oil spill studies: A review of ecological effects

    SciTech Connect

    Teal, J.M.; Howarth, R.W.

    1984-01-01

    The authors reviewed seven particularly well known and/or studied oil spills that have occurred since the National Academy of Sciences 1975 report, ''Petroleum in the Marine Environment'' or that occurred prior to that report but about which significant new information has since been acquired. The spills studied were from the barge Florida, and tankers Arrow, Argo Merchant, Amoco Cadiz, and Tsesis and blowouts from the Bravo and Ixtoc I platforms. These ''best'' studies yield only limited insight into effects because they lack controls and have a high degree of natural variability. The Tsesis, Florida, and Amoco Cadiz cases are exceptional since they occurred in areas of ongoing research programs and had nearby areas suitable for controls. Oil spills have produced measurable effects on ecosystems that have not been readily predictable from laboratory studies on isolated organisms. However, ecosystemlevel interactions are poorly understood even without the complications resulting from effects of pollution. These generalizations emerge: oil regularly reaches sediments after a spill; oil in anoxic sediments is persistent; oil regularly contaminates zooplankton and benthic invertebrates; fish are also contaminated, but to a lesser extent; oil contamination decreases the abundance and diversity of benthic communities.

  14. Host community structure and infestation by ixodid ticks: repeatability, dilution effect and ecological specialization.

    PubMed

    Krasnov, Boris R; Stanko, Michal; Morand, Serge

    2007-11-01

    Abundance of a species in a location results from the interplay between the intrinsic properties of that species and the extrinsic properties, both biotic and abiotic, of the local habitat. Intrinsic factors promote among-population stability in abundance, whereas extrinsic factors generate variation among populations of a species. We studied (a) repeatability and (b) the effect of abundance and species richness of small mammals on the level of their infestation by larvae and nymphs of Ixodes ricinus (ecological generalist) and Ixodes trianguliceps (ecological specialist). We asked if tick infestation parameters are characteristic (=repeatable) for a particular host species or a particular stage of a particular tick species. We also asked how abundance and diversity of hosts affect the level of tick infestation on a particular host species. We predicted that the dilution effect (decrease in tick infestation levels with an increase of host abundance and/or species richness) will be better expressed in an ecological generalist, I. ricinus, than in an ecological specialist, I. trianguliceps. We found that (a) tick abundance, prevalence and aggregation were generally repeatable within tick species/stage; (b) tick abundance and prevalence, but not the aggregation level, were repeatable within host species; (c) the proportion of variance among samples explained by the differences between tick species and stages (as opposed to within-tick species and stage) was higher than that explained by the differences between host species (as opposed to within host species); and (d) the relationship between tick infestation parameters and host abundance and diversity revealed the dilution effect for I. ricinus but not for I. trianguliceps. PMID:17684769

  15. Surveying Hydrology, Ecology, and Climate Effects of Northern Peatlands

    NASA Astrophysics Data System (ADS)

    Slater, Lee; Comas, Xavier; Reeve, Andrew; Jol, Harry

    2007-10-01

    Peatlands Geophysics Workshop, Orono, Maine, 11-15 June 2007 Northern peatlands comprise the largest wetland complex worldwide, covering approximately 4 million square kilometers across Eurasia and North America. They form a critical component of the global carbon (C) cycle by acting as net sources of CH4 but net sinks of CO2. Studies of northern peatlands have increased in recent years due to uncertainties in (1) mechanisms and rates of carbon gas exchange between peatlands and the atmosphere, and (2) the effect of northern-latitude climate warming on peatland-atmosphere carbon gas fluxes.

  16. Estimating the Cumulative Ecological Effect of Local Scale Landscape Changes in South Florida

    USGS Publications Warehouse

    Hogan, Dianna M.; Labiosa, William; Pearlstine, Leonard; Hallac, David; Strong, David; Hearn, Paul; Bernknopf, Richard

    2012-01-01

    Ecosystem restoration in south Florida is a state and national priority centered on the Everglades wetlands. However, urban development pressures affect the restoration potential and remaining habitat functions of the natural undeveloped areas. Land use (LU) planning often focuses at the local level, but a better understanding of the cumulative effects of small projects at the landscape level is needed to support ecosystem restoration and preservation. The South Florida Ecosystem Portfolio Model (SFL EPM) is a regional LU planning tool developed to help stakeholders visualize LU scenario evaluation and improve communication about regional effects of LU decisions. One component of the SFL EPM is ecological value (EV), which is evaluated through modeled ecological criteria related to ecosystem services using metrics for (1) biodiversity potential, (2) threatened and endangered species, (3) rare and unique habitats, (4) landscape pattern and fragmentation, (5) water quality buffer potential, and (6) ecological restoration potential. In this article, we demonstrate the calculation of EV using two case studies: (1) assessing altered EV in the Biscayne Gateway area by comparing 2004 LU to potential LU in 2025 and 2050, and (2) the cumulative impact of adding limestone mines south of Miami. Our analyses spatially convey changing regional EV resulting from conversion of local natural and agricultural areas to urban, industrial, or extractive use. Different simulated local LU scenarios may result in different alterations in calculated regional EV. These case studies demonstrate methods that may facilitate evaluation of potential future LU patterns and incorporate EV into decision making.

  17. Biomarker-based biomonitoring for evaluating health and ecological effects on environmental contamination

    SciTech Connect

    McCarthy, J.F.; Shugart, L.R.; Jimenez, B.D.

    1991-01-01

    This paper describes a research approach for assessing the biological and ecological significance of contaminants present in the environment. The approach uses wild animals and introduced caged animals near hazardous waste sites as (1) sentinels of bioavailable contaminants, (2) predictors of adverse ecological effects, and (3) surrogates to estimate the potential exposure and risks to humans living near these sites. Evidence of exposure in animals on the site provides a temporally-integrated measure of bioavailable contaminant levels and is therefore much more relevant to the potential risk to humans than is the analytically measurable concentration of contaminants in the soil, water, or air. The research approach utilizes biomarkers (biochemical, molecular and cellular indicators of exposure) and measures of body burden of persistent compounds (such as polychlorinated biphenyls; PCBs) in wild animals captured on a hazardous waste disposal site and in adjacent uncontaminated reference areas to identify and quantify the potential for exposure to bioavailable contaminants. Unexposed animals confined at sites confirm the potential for environmental exposure. Relationships between biomarker response and adverse ecological effects are determined from measures of animal health and population structure. The potential risk to humans is extrapolated from the animal exposure data using pharmacodynamic models. 76 refs., 8 figs., 4 tabs.

  18. Estimating the cumulative ecological effect of local scale landscape changes in south Florida.

    PubMed

    Hogan, Dianna M; Labiosa, William; Pearlstine, Leonard; Hallac, David; Strong, David; Hearn, Paul; Bernknopf, Richard

    2012-02-01

    Ecosystem restoration in south Florida is a state and national priority centered on the Everglades wetlands. However, urban development pressures affect the restoration potential and remaining habitat functions of the natural undeveloped areas. Land use (LU) planning often focuses at the local level, but a better understanding of the cumulative effects of small projects at the landscape level is needed to support ecosystem restoration and preservation. The South Florida Ecosystem Portfolio Model (SFL EPM) is a regional LU planning tool developed to help stakeholders visualize LU scenario evaluation and improve communication about regional effects of LU decisions. One component of the SFL EPM is ecological value (EV), which is evaluated through modeled ecological criteria related to ecosystem services using metrics for (1) biodiversity potential, (2) threatened and endangered species, (3) rare and unique habitats, (4) landscape pattern and fragmentation, (5) water quality buffer potential, and (6) ecological restoration potential. In this article, we demonstrate the calculation of EV using two case studies: (1) assessing altered EV in the Biscayne Gateway area by comparing 2004 LU to potential LU in 2025 and 2050, and (2) the cumulative impact of adding limestone mines south of Miami. Our analyses spatially convey changing regional EV resulting from conversion of local natural and agricultural areas to urban, industrial, or extractive use. Different simulated local LU scenarios may result in different alterations in calculated regional EV. These case studies demonstrate methods that may facilitate evaluation of potential future LU patterns and incorporate EV into decision making. PMID:22037616

  19. Estimating the Cumulative Ecological Effect of Local Scale Landscape Changes in South Florida

    NASA Astrophysics Data System (ADS)

    Hogan, Dianna M.; Labiosa, William; Pearlstine, Leonard; Hallac, David; Strong, David; Hearn, Paul; Bernknopf, Richard

    2012-02-01

    Ecosystem restoration in south Florida is a state and national priority centered on the Everglades wetlands. However, urban development pressures affect the restoration potential and remaining habitat functions of the natural undeveloped areas. Land use (LU) planning often focuses at the local level, but a better understanding of the cumulative effects of small projects at the landscape level is needed to support ecosystem restoration and preservation. The South Florida Ecosystem Portfolio Model (SFL EPM) is a regional LU planning tool developed to help stakeholders visualize LU scenario evaluation and improve communication about regional effects of LU decisions. One component of the SFL EPM is ecological value (EV), which is evaluated through modeled ecological criteria related to ecosystem services using metrics for (1) biodiversity potential, (2) threatened and endangered species, (3) rare and unique habitats, (4) landscape pattern and fragmentation, (5) water quality buffer potential, and (6) ecological restoration potential. In this article, we demonstrate the calculation of EV using two case studies: (1) assessing altered EV in the Biscayne Gateway area by comparing 2004 LU to potential LU in 2025 and 2050, and (2) the cumulative impact of adding limestone mines south of Miami. Our analyses spatially convey changing regional EV resulting from conversion of local natural and agricultural areas to urban, industrial, or extractive use. Different simulated local LU scenarios may result in different alterations in calculated regional EV. These case studies demonstrate methods that may facilitate evaluation of potential future LU patterns and incorporate EV into decision making.

  20. Intestinal nutrient absorption - A biomarker for deleterious heavy metals in aquatic environments

    SciTech Connect

    Farmanfarmaian, A. (Rutgers, The State Univ. of New Jersey, Piscataway (USA))

    1988-09-01

    The deleterious effects of heavy metals on absorptive processes at the membrane surface will be summarized. Among the deleterious heavy metal chlorides (HgCl{sub 2}, CH{sub 3}HgCl, CdCl{sub 2}, CoCl{sub 2}, SrCl{sub 2}) tested HgCl{sub 2}, CH{sub 3}HgCl, and CdCl{sub 2} inhibit the absorption of several amino acids and sugars (L-leucine, L-methionine, L-isoleucine, L-lysine, cyclolencine, D-glucose, and D-galactose). The dose dependent inhibition of L-leucine uptake by HgCl{sub 2} is shown in a number of fish from different collection sites representing nektonic plankton feeders as well as demersal carnivores. The same type of data is shown for both HgCl{sub 2} and HC{sub 3}HgCl in the case of the commercially important summer flounder. Since the overall rate of intestinal absorption of amino acids and sugars involves the three processes of simple diffusion, protein-mediated facilitated diffusions, and protein-mediated sodium dependent active transport, the inhibition of the overall rate may not be sensitive enough as a biomarker. However, the active component, which alone accumulates essential amino acids in the tissue, appears to be very sensitive and can be used as a biomarker. The terminal tissue-to-medium (T/M) ratio of L-leucine concentration shows a 2-3 fold accumulation in the absence of mercury. Since the diffusional components can at best equilibrate L-leucine across the membrane % inhibition of the active component can be calculated after subtracting 1 from the experimental T/M values. The resulting inhibition is very sever ranging from approximately 50-100% for HgCl{sub 2} and 20-70% for CH{sub 3}HgCl over a range of 5-20 ppm of mercury.

  1. Water cycles in closed ecological systems: effects of atmospheric pressure

    NASA Technical Reports Server (NTRS)

    Rygalov, Vadim Y.; Fowler, Philip A.; Metz, Joannah M.; Wheeler, Raymond M.; Bucklin, Ray A.; Sager, J. C. (Principal Investigator)

    2002-01-01

    In bioregenerative life support systems that use plants to generate food and oxygen, the largest mass flux between the plants and their surrounding environment will be water. This water cycle is a consequence of the continuous change of state (evaporation-condensation) from liquid to gas through the process of transpiration and the need to transfer heat (cool) and dehumidify the plant growth chamber. Evapotranspiration rates for full plant canopies can range from 1 to 10 L m-2 d-1 (1 to 10 mm m-2 d-1), with the rates depending primarily on the vapor pressure deficit (VPD) between the leaves and the air inside the plant growth chamber. VPD in turn is dependent on the air temperature, leaf temperature, and current value of relative humidity (RH). Concepts for developing closed plant growth systems, such as greenhouses for Mars, have been discussed for many years and the feasibility of such systems will depend on the overall system costs and reliability. One approach for reducing system costs would be to reduce the operating pressure within the greenhouse to reduce structural mass and gas leakage. But managing plant growth environments at low pressures (e.g., controlling humidity and heat exchange) may be difficult, and the effects of low-pressure environments on plant growth and system water cycling need further study. We present experimental evidence to show that water saturation pressures in air under isothermal conditions are only slightly affected by total pressure, but the overall water flux from evaporating surfaces can increase as pressure decreases. Mathematical models describing these observations are presented, along with discussion of the importance for considering "water cycles" in closed bioregenerative life support systems.

  2. Experimental evidence that ecological effects of an invasive fish are reduced at high densities.

    PubMed

    Kornis, Matthew S; Carlson, Jedchada; Lehrer-Brey, Gabrielle; Vander Zanden, M Jake

    2014-05-01

    Understanding the relationship between invasive species density and ecological impact is a pressing topic in ecology, with implications for environmental management and policy. Although it is widely assumed that invasive species impact will increase with density, theory suggests interspecific competition may diminish at high densities due to increased intraspecific interactions. To test this theory, we experimentally examined intra- and interspecific interactions between a globally invasive fish, round goby (Neogobius melanostomus), and three native species at different round goby densities in a tributary of the Laurentian Great Lakes. Eighteen 2.25 m(2) enclosures were stocked with native fish species at natural abundances, while round gobies were stocked at three different densities: 0 m(-2), 2.7 m(-2), and 10.7 m(-2). After 52 days, native fish growth rate was significantly reduced in the low density goby treatment, while growth in the high density goby treatment mirrored the goby-free treatment for two of three native species. Invertebrate density and gut content weight of native fishes did not differ among treatments. Conversely, gut content weight and growth of round gobies were lower in the high goby density treatment, suggesting interactions between round gobies and native fishes are mediated by interference competition amongst gobies. Our experiment provides evidence that invasive species effects may diminish at high densities, possibly due to increased intraspecific interactions. This is consistent with some ecological theory, and cautions against the assumption that invasive species at moderate densities have low impact. PMID:24532212

  3. K. A. Garrett and C. M. Cox. Applied biodiversity science: Managing emerging diseases in agriculture and linked natural systems using 1 ecological principles. Pages 368-386 in Infectious disease ecology: The effects of ecosystems on disease and of disease

    E-print Network

    Garrett, Karen A.

    K. A. Garrett and C. M. Cox. Applied biodiversity science: Managing emerging diseases in agriculture and linked natural systems using 1 ecological principles. Pages 368-386 in Infectious disease ecology: The effects of ecosystems on disease and of disease on ecosystems. R. Ostfeld, F. Keesing, and V

  4. Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities.

    PubMed

    Fabricius, K E; De'ath, G; Noonan, S; Uthicke, S

    2014-01-22

    The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO2 (425-1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO2 tolerances derived from laboratory experiments. High CO2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs. PMID:24307670

  5. Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities

    PubMed Central

    Fabricius, K. E.; De'ath, G.; Noonan, S.; Uthicke, S.

    2014-01-01

    The ecological effects of ocean acidification (OA) from rising atmospheric carbon dioxide (CO2) on benthic marine communities are largely unknown. We investigated in situ the consequences of long-term exposure to high CO2 on coral-reef-associated macroinvertebrate communities around three shallow volcanic CO2 seeps in Papua New Guinea. The densities of many groups and the number of taxa (classes and phyla) of macroinvertebrates were significantly reduced at elevated CO2 (425–1100 µatm) compared with control sites. However, sensitivities of some groups, including decapod crustaceans, ascidians and several echinoderms, contrasted with predictions of their physiological CO2 tolerances derived from laboratory experiments. High CO2 reduced the availability of structurally complex corals that are essential refugia for many reef-associated macroinvertebrates. This loss of habitat complexity was also associated with losses in many macroinvertebrate groups, especially predation-prone mobile taxa, including crustaceans and crinoids. The transition from living to dead coral as substratum and habitat further altered macroinvertebrate communities, with far more taxa losing than gaining in numbers. Our study shows that indirect ecological effects of OA (reduced habitat complexity) will complement its direct physiological effects and together with the loss of coral cover through climate change will severely affect macroinvertebrate communities in coral reefs. PMID:24307670

  6. Pleistocene and ecological effects on continental-scale genetic differentiation in the bobcat (Lynx rufus).

    PubMed

    Reding, Dawn M; Bronikowski, Anne M; Johnson, Warren E; Clark, William R

    2012-06-01

    The potential for widespread, mobile species to exhibit genetic structure without clear geographic barriers is a topic of growing interest. Yet the patterns and mechanisms of structure--particularly over broad spatial scales--remain largely unexplored for these species. Bobcats occur across North America and possess many characteristics expected to promote gene flow. To test whether historical, topographic or ecological factors have influenced genetic differentiation in this species, we analysed 1 kb mtDNA sequence and 15 microsatellite loci from over 1700 samples collected across its range. The primary signature in both marker types involved a longitudinal cline with a sharp transition, or suture zone, occurring along the Great Plains. Thus, the data distinguished bobcats in the eastern USA from those in the western half, with no obvious physical barrier to gene flow. Demographic analyses supported a scenario of expansion from separate Pleistocene refugia, with the Great Plains representing a zone of secondary contact. Substructure within the two main lineages likely reflected founder effects, ecological factors, anthropogenic/topographic effects or a combination of these forces. Two prominent topographic features, the Mississippi River and Rocky Mountains, were not supported as significant genetic barriers. Ecological regions and environmental correlates explained a small but significant proportion of genetic variation. Overall, results implicate historical processes as the primary cause of broad-scale genetic differentiation, but contemporary forces seem to also play a role in promoting and maintaining structure. Despite the bobcat's mobility and broad niche, large-scale landscape changes have contributed to significant and complex patterns of genetic structure. PMID:22548482

  7. Effective Ecological Restoration of Collapsed Ecosystems - Linking Soil, Water and Society

    NASA Astrophysics Data System (ADS)

    Petursdottir, Thorunn; Finger, David

    2014-05-01

    All natural resources, utilized by humans are embedded in complex social-ecological systems (SESs). To maintain the systems' sustainability, the SESs needs to be managed within their resilience optimum, considering both social and ecological elements. Throughout the centuries the humankind has often failed in doing so. Overexploitation of natural resources has thus widely disrupted equilibrium within the respective SESs, driving unforeseen changes of ecosystems worldwide. Anthropogenic factors such as poor institutional structure on resource utilization and weak policies in combination to environmental factors like droughts, fires or other unpredictable events have ruptured ecosystems' resilience and caused global degradation on a scale that currently threatens the Earth's welfare. As an example it's worth to mention that up to 40% of the world's agricultural land is severely degraded mainly due to unsustainable landuse. Once an ecosystem, or part/s of it, have collapsed, ecological restoration is almost always necessary to overcome the threshold/s that may prevent the system from self-recovering. It also re-activates the system's environmental cycles like the water, carbon and nutrient circulation. Although soil is the fundamental body of terrestrial ecosystems, water availability is of equal importance and should be taken more into consideration in restoration than currently is done. Based on that, we will focus on how to best manage effective large-scale ecological restoration (LSER) of collapsed ecosystems and link it to water catchment areas. LSER is a fundamental social-ecological activity that substantially can improve ecosystem condition, human livelihood and if well organized, facilitate improved management of natural resources. By definition, restoration of ecological integrity and functions is the fundamental basis for all restoration activities. But to achieve long-term sustainability of LSER activities the initial set of rules/policies established by the stakeholders or the government must be congruent with local condition in context to regional, national and even global perspectives. The related parties need to be in agreement to the content of the existing policies related to large-scale restoration and collectively work on achieving their targets. The actors must operate in line with the existing laws and legislation. Furthermore, all the multiple layers of the governance system need to cooperate internally in a transparent and decentralized way on attaining LSER targets; through for instance local restoration projects and improved land management. To assess if the policies are facilitating the expected LSER progress, a monitoring and evaluation system should also be in place. Researches indicate that incoherency within the governance system and lack of social cohesion can significantly reduce the expected outcome of restoration projects. Here we will present an ecological restoration model based on a SES framework that can be used to analyse the SESs the restoration activities will take place within. The model can also be used to organize restoration projects on different scales, to identify potential leverage points or gaps within the SES and to design a tailor-made monitoring and evaluation program.

  8. Ecological uses of tourmaline

    Microsoft Academic Search

    K. Shigenobu; T. Matsumura; T. Nakamura; H. Ishii; Y. Nishi

    1999-01-01

    Tourmaline is very famous as the birthstone of October. It is also generally known as a mineral with piezoelectricity and pyroelectricity. Furthermore, tourmaline is expected as one of the ecological and intelligent materials. Thus, the authors introduce the effects of tourmaline on ecological properties. Furthermore, tourmaline enhances the growth rate of plants. From an ecological paint of view, they introduce

  9. Fire Ecology

    NSDL National Science Digital Library

    Forest fires have become a regular summertime occurrence in North America, sparking debate about the proper role of fire on the land. The following websites examine fires and fire ecology in different ecosystems, regions, and time periods. The first site (1), from the USGS-Western Ecological Research Center shares information about fire ecology research in the California shrublands, Sierra Nevada forests, and Mohave and Sonoran deserts. The second site (2) features the Fire Ecology Center at Texas Tech University. The Fire Ecology Center focuses on the role of fire in grassland ecosystems and their website contains information on current research, publications, managing pastures, managing problem plants, and more. The third site (3), from the USGS-Northern Prairie Wildlife Research Center contains "an annotated bibliography on fire in North American wetland ecosystems and a subject index of all fire-related literature that has appeared in Wildlife Review." Hosted by Yellowstone National Park, the fourth site (4) addresses wildland fires in Yellowstone. The Park website presents brief sections on Fire Ecology, Fire Monitoring, Prescribed Fire, and Fire Effects -- to name a few. The fifth (5) site, from the Canadian Forest Service, provides information about forest fires in Canada including weekly fire statistics, fire research, daily fire maps, a fire database, and more. Part of a great site on the land use history of the Colorado Plateau from Northern Arizona University, the sixth site (6) offers a brief overview of wildfire history and ecology on the Plateau with links to information about ponderosa pine fire ecology, reintroduction of fire to forest ecosystems, and fire ecology research studies. The seventh site (7), from DiscoverySchool.com, contains a lesson plan on forest fire ecology for grade levels 9-12. The lesson spans two class periods and the site provides objectives, materials needed, discussion questions, academic standards, and more. The final (8) website, from the Why Files, "examines the role of fire in natural systems, and the role of science in understanding wildfires." The eleven-page website follows a kid-friendly narrative format and includes a bibliography and glossary.

  10. Ecological impacts of umbrella effects of radiation on the individual members.

    PubMed

    Doi, Masahiro; Kawaguchi, Isao

    2007-01-01

    In order to study the interactions in a model aquatic microcosm, an individual-based computer simulation model was developed. The microcosm consists of Euglena gracilis as an autotroph algae, Tetrahymena thermophila as a heterotroph protozoa and Escherichia coli as a saprotroph bacteria. There exists a strong interaction between Tetrahymena and E. coli as the first is the predator of the second. Ecological toxicity tests were conducted to test the population level impacts of the biological effects of radiation and toxicants on the lethality and mobility factors that influence directly or indirectly growth and reproduction. Radiological effects on lethality of E. coli individuals were translated to the reduction of the equilibrium population of Tetrahymena. A synergistic effect at the community level was also observed by the simulation of a combined exposure of radiation and a toxicant which reduced the feeding efficiency of Tetrahymena. PMID:17459541

  11. Ecological effects of nitrogen and sulfur air pollution in the US: what do we know?

    USGS Publications Warehouse

    Greaver, Tara L.; Sullivan, Timothy J.; Herrick, Jeffrey D.; Barber, Mary C.; Baron, Jill S.; Cosby, Bernard J.; Deerhake, Marion E.; Dennis, Robin L.; Dubois, Jean-Jacque B.; Goodale, Christine L.; Herlihy, Alan T.; Lawrence, Gregory B.; Liu, Lingli; Lynch, Jason A.; Novak, Kristopher J.

    2012-01-01

    Four decades after the passage of the US Clean Air Act, air-quality standards are set to protect ecosystems from damage caused by gas-phase nitrogen (N) and sulfur (S) compounds, but not from the deposition of these air pollutants to land and water. Here, we synthesize recent scientific literature on the ecological effects of N and S air pollution in the US. Deposition of N and S is the main driver of ecosystem acidification and contributes to nutrient enrichment in many natural systems. Although surface-water acidification has decreased in the US since 1990, it remains a problem in many regions. Perturbations to ecosystems caused by the nutrient effects of N deposition continue to emerge, although gas-phase concentrations are generally not high enough to cause phytotoxicity. In all, there is overwhelming evidence of a broad range of damaging effects to ecosystems in the US under current air quality conditions.

  12. Cascading ecological effects of low-level phosphorus enrichment in the Florida Everglades

    USGS Publications Warehouse

    Gaiser, E.E.; Trexler, J.C.; Richards, J.H.; Childers, D.L.; Lee, D.; Edwards, A.L.; Scinto, L.J.; Jayachandran, K.; Noe, G.B.; Jones, R.D.

    2005-01-01

    Few studies have examined long-term ecological effects of sustained low-level nutrient enhancement on wetland biota. To determine sustained effects of phosphorus (P) addition on Everglades marshes we added P at low levels (5, 15, and 30 ??g L-1 above ambient) for 5 yr to triplicate 100-m flow-through channels in pristine marsh. A cascade of ecological responses occurred in similar sequence among treatments. Although the rate of change increased with dosing level, treatments converged to similar enriched endpoints, characterized most notably by a doubling of plant biomass and elimination of native, calcareous periphyton mats. The full sequence of biological changes occurred without an increase in water total P concentration, which remained near ambient levels until Year 5. This study indicates that Everglades marshes have a near-zero assimilative capacity for P without a state change, that ecosystem responses to enrichment accumulate over time, and that downstream P transport mainly occurs through biota rather than the water column.

  13. [Effect of ridge & terraced ecological rice farming on rice photosynthetic characteristics and yield].

    PubMed

    Zheng, Hua-Bin; Liu, Jian-Xia; Yao, Lin; He, Hui; Huang, Huang

    2014-09-01

    Taking super hybrid rice Y-liangyou 1, and hybrid rice Xianyou 63 and conventional rice Huanghuazhan as test materials, a field experiment was conducted in Changsha City of Hunan Province in 2011 and 2012 to investigate the effects of ridge & terraced ecological rice farming (RT) and bed ecological rice farming (B) on rice grain yield and photosynthetic characteristics. Compared with conventional rice farming (CK) , yield of Y-liangyou 1 in the RT was increased significantly by 28.7%, the effective panicles per unit area and spikelets per panicle were increased by 16.1% and 6.8%, respectively. Yields of Xianyou 63 and Huanghuazhan in the RT and B were 24.3% and 19.7%, 12.0% and 16.2% higher than those of CK, respectively. Leaf area index, dry matter accumulation before and after full-heading, total dry matter accumulation of Y-liangyou 1 in the RT was higher than that of CK. Number of spikelets/leaf area, number of filled grains/leaf area, grain mass/leaf area of Y-liangyou 1 in the RT were 8.1%, 14.8% and 15.8% higher than those of CK, respectively, the photosynthetic potential was increased by 32.2% while the net assimilation rate was declined by 9.3%. PMID:25757311

  14. [Ecological effect of different types land consolidation in Hubei Province of China].

    PubMed

    Gu, Xiao-Kun

    2012-08-01

    A model for estimating the ecosystem services value under effects of land consolidation was built to quantitatively evaluate the ecological effects of three different types of land consolidation projects in Jianghan Plain, middle hilly region, and western mountainous area of Hubei Province. With the implementation of the projects, the total value of ecosystem services in Jianghan Plain was decreased by 0.3%, among which, the values of food production service and other three services increased but those of water conservation and other four services decreased. In hilly region, the total value of ecosystem services was decreased by 14.6%, with the value of food production service increased by 55.2% and those of other eight services all decreased. In mountainous area, the total value of ecosystem services was decreased by 19.9%, with the value of food production service increased by 24.9% while the values of other eight services all decreased. In the land consolidation in the middle hilly region and western mountainous area of Hubei Province, there was an obvious conversion process 'from ecology to production' in the ecosystem services value. PMID:23189708

  15. The Effect of an Ecological Imagery Program on Soccer Performance of Elite Players

    PubMed Central

    Seif-Barghi, Tohid; Kordi, Ramin; Memari, Amir-Hossein; Mansournia, Mohammad-Ali; Jalali-Ghomi, Majid

    2012-01-01

    Purpose Despite the acknowledged impact of imagery on performance, ecologically sound studies investigating imagery and its effects on performance subcomponents in real games are surprisingly limited. The aim of this study was to investigate the effects of imagery training on passing improvement in elite soccer players. Methods Sixty nine soccer players taking part in the national championship leagues in four age categories including U16, U19, U21 and over 21 were randomly assigned to the imagery and control groups. Interventional group participants completed an 8 week video-aided, cognitive imagery program on how to make a perfect soccer pass. Results Performance analysis through close video analysis showed that successful pass rate increased significantly in the intervention group compared to control (OR = 1.19, P=0.002, 95%CI = 1.06-1.33). Further analysis revealed that the results are statistically significant in U16 and U21 but not other categories. Conclusions We concluded that successful soccer passing through real competitions as a multidimensional and critical open skill could be enhanced by an ecologically sound method of mental imagery. PMID:22942993

  16. Ecologically relevant geomorphic attributes of streams are impaired by even low levels of watershed effective imperviousness

    NASA Astrophysics Data System (ADS)

    Vietz, Geoff J.; Sammonds, Michael J.; Walsh, Christopher J.; Fletcher, Tim D.; Rutherfurd, Ian D.; Stewardson, Michael J.

    2014-02-01

    Urbanization almost inevitably results in changes to stream morphology. Understanding the mechanisms for such impacts is a prerequisite to minimizing stream degradation and achieving restoration goals. However, investigations of urban-induced changes to stream morphology typically use indicators of watershed urbanization that may not adequately represent degrading mechanisms and commonly focus on geomorphic attributes such as channel dimensions that may be of little significance to the ecological goals for restoration. We address these shortcomings by testing if a measure characterizing urban stormwater drainage system connections to streams (effective imperviousness, EI) is a better predictor of change to ecologically relevant geomorphic attributes than a more general measure of urban density (total imperviousness, TI). We test this for 17 sites in independent watersheds across a gradient of urbanization. We found that EI was a better predictor of all geomorphic variables tested than was TI. Bank instability was positively correlated with EI, while width/depth (a measure of channel incision), bedload sediment depth, and frequency of bars, benches, and large wood were negatively correlated. Large changes in all geomorphic variables were detected at very low levels of EI (< 2-3%). Excess urban stormwater runoff, as represented by EI, drives geomorphic change in urban streams, highlighting the dominant role of the stormwater drainage system in efficiently transferring stormwater runoff from impervious surfaces to the stream, as found for ecological indicators. It is likely that geomorphic condition of streams in urbanizing watersheds, particularly those attributes of ecological relevance, can only be maintained if excess urban stormwater flows are kept out of streams through retention and harvesting. The extent to which EI can be reduced within urban and urbanizing watersheds, through techniques such as distributed stormwater harvesting and infiltration, and the components of the hydrologic regime to be addressed, requires further investigation. Urbanization influences stream morphology more than any other land use (Douglas, 2011): it alters hydrology and sediment inputs leading to deepening and widening of streams (Chin, 2006). Concomitantly, urbanization often directly impairs stream morphology through channel and riparian zone interventions, e.g., culverts (Hawley et al., 2012), rock protection (Vietz et al., 2012b), and constricted floodplains (Gurnell et al., 2007). These changes to channel geomorphology in turn contribute to poor in-stream ecological condition (Morley and Karr, 2002; Walsh et al., 2005b; Gurnell et al., 2007; Elosegi et al., 2010).The common conception is that channels undergo gross morphologic alterations if > 10-20% of their watershed is covered by impervious surfaces (total imperviousness, TI; Bledsoe and Watson, 2001; Chin, 2006; Table 1). Many of these studies may, however, underestimate the influence of urbanization by using insensitive channel metrics and assessing streams in early stages of urbanization. Most importantly, TI, as a measure of urban density, may not adequately represent the way in which urbanization alters the master variables of flow and sediment within a watershed.Hydrologists have long recognized that, rather than the proportion of impervious cover within a watershed, it is the proportion that is directly connected to the stream through stormwater drainage systems that may be a better predictor of urban-induced hydrologic change (Leopold, 1968). Referred to as effective imperviousness (EI) the proportion of impervious cover directly connected to the stream through stormwater drainage systems may also be a better predictor of geomorphic response than is TI. Over the last decade a direct measure of EI has been found to be a better predictor of ecological response in urban streams (Walsh et al., 2012), but use of such a metric has not found its way into geomorphic studies even though TI has been found to be ineffective (e.g., Bledsoe et al.,

  17. SYNTHESIS Ecological impacts of invasive alien plants: a meta-analysis of their effects on species, communities and ecosystems

    E-print Network

    Kratochvíl, Lukas

    REVIEW AND SYNTHESIS Ecological impacts of invasive alien plants: a meta-analysis of their effects-analysis of 199 articles reporting 1041 field studies that in total describe the impacts of 135 alien plant taxa on resident species, communities and ecosystems. Across studies, alien plants had a significant effect in 11

  18. Ecological effects of crude oil residues on the functional diversity of soil microorganisms in three weed rhizospheres

    Microsoft Academic Search

    Qian-ru ZHANG; Qi-xing ZHOU; Li-ping REN; Yong-guan ZHU; Shu-lan SUN

    2006-01-01

    Ecological effects of crude oil residues on weed rhizospheres are still vague. The quantitative and diversity changes and metabolic responses of soil-bacterial communities in common dandelion (Taraxacum officinale), jerusalem artichoke (Silphium perfoliatum L.) and evening primrose (Acalypha australis L.) rhizospheric soils were thus examined using the method of carbon source utilization. The results indicated that there were various toxic effects

  19. Literature Review on the Effects of Prescription Fire on theEcology of Site 300

    SciTech Connect

    Preston, R

    2011-03-14

    Lawrence Livermore National Laboratory has historically conducted prescription burns across approximately 2,000 acres of Site 300 on an annual basis to safeguard test facilities and operations from the risk of wildfire encroachment. Prescription burns began in 1960, and although fire frequency varies among the designated burn areas, all have been burned at least once. A patchwork of native perennial grassland communities and associated special-status plant and animal populations occur onsite in many areas that have been receiving these treatments. Because the size and locations of prescription burns may shift in coming years, an evaluation is warranted to determine how these shifts may affect listed biota, including rare plants, and the distinct ecological conditions present on the site. This report presents the results of a literature review conducted by ICF International (ICF) to collect basic information on native perennial grasslands in California, the influence of fire on these grasslands, and management tools for restoring and maintaining them. The objective of this study was to review the scientific literature on California native grasslands and summarize the current state of knowledge pertaining to the possible effects -- both beneficial and detrimental -- of prescribed fire on the ecology of Site 300. The results of this review are intended to inform future management practices that may be carried out at Site 300 to maintain the plant and wildlife communities and to ensure that the ecological conditions benefit the special-status species that inhabit the Site. This review is also intended to identify a study approach to investigate changes over the next 10 years in the burned areas and in areas where burning will be discontinued.

  20. Deleterious myocardial consequences induced by intermittent hypoxia are reversed by erythropoietin.

    PubMed

    Ramond, A; Ribuot, C; Lévy, P; Joyeux-Faure, M

    2007-06-15

    The aim of this work was to investigate the effects of different recombinant human erythropoietin (rhEPO) doses on the infarction development and if rhEPO could protect against the deleterious consequences induced by a previous intermittent hypoxia (IH, FiO(2) 5%, 4h). First, isolated rat hearts were submitted to an ischemia-reperfusion. rhEPO was infused before or after ischemia, at different doses. Secondly, rats were exposed to of IH. Twenty-four hours later, hearts underwent the ischemia-reperfusion protocol. For some hearts, 5Uml(-1) rhEPO was infused as previously. We observed that rhEPO has a dose-dependant effect on infarct size since it was significantly reduced by rhEPO infusions before or after ischemia. We also showed that 4h of IH induced a higher sensitivity to the infarction which was prevented by rhEPO. In conclusion, rhEPO administration before or after ischemia can protect isolated rat myocardium in a dose dependent manner and efficiently prevents the higher sensitivity to the infarction induced by previous intermittent hypoxia. PMID:17161979

  1. Enhancing knowledge of rangeland ecological processes with benchmark ecological sites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A benchmark ecological site is one that has the greatest potential to yield data and information about ecological functions, processes, and the effects of management or climate changes on a broad area or critical ecological zone. A benchmark ecological site represents other similar sites in a major ...

  2. The genetics of indirect ecological effects—plant parasites and aphid herbivores

    PubMed Central

    Rowntree, Jennifer K.; Zytynska, Sharon E.; Frantz, Laurent; Hurst, Ben; Johnson, Andrew; Preziosi, Richard F.

    2014-01-01

    When parasitic plants and aphid herbivores share a host, both direct and indirect ecological effects (IEEs) can influence evolutionary processes. We used a hemiparasitic plant (Rhinanthus minor), a grass host (Hordeum vulgare) and a cereal aphid (Sitobion avenae) to investigate the genetics of IEEs between the aphid and the parasitic plant, and looked to see how these might affect or be influenced by the genetic diversity of the host plants. Survival of R. minor depended on the parasite's population of origin, the genotypes of the aphids sharing the host and the genetic diversity in the host plant community. Hence the indirect effects of the aphids on the parasitic plants depended on the genetic environment of the system. Here, we show that genetic variation can be important in determining the outcome of IEEs. Therefore, IEEs have the potential to influence evolutionary processes and the continuity of species interactions over time. PMID:24782886

  3. The genetics of indirect ecological effects-plant parasites and aphid herbivores.

    PubMed

    Rowntree, Jennifer K; Zytynska, Sharon E; Frantz, Laurent; Hurst, Ben; Johnson, Andrew; Preziosi, Richard F

    2014-01-01

    When parasitic plants and aphid herbivores share a host, both direct and indirect ecological effects (IEEs) can influence evolutionary processes. We used a hemiparasitic plant (Rhinanthus minor), a grass host (Hordeum vulgare) and a cereal aphid (Sitobion avenae) to investigate the genetics of IEEs between the aphid and the parasitic plant, and looked to see how these might affect or be influenced by the genetic diversity of the host plants. Survival of R. minor depended on the parasite's population of origin, the genotypes of the aphids sharing the host and the genetic diversity in the host plant community. Hence the indirect effects of the aphids on the parasitic plants depended on the genetic environment of the system. Here, we show that genetic variation can be important in determining the outcome of IEEs. Therefore, IEEs have the potential to influence evolutionary processes and the continuity of species interactions over time. PMID:24782886

  4. Demography of birds in a neotropical forest: Effects of allometry, taxonomy, and ecology

    USGS Publications Warehouse

    Brawn, J.D.; Karr, J.R.; Nichols, J.D.

    1995-01-01

    Comparative demographic studies of terrestrial vertebrates have included few samples of species from tropical forests. We analyzed 9 yr of mark-recapture data and estimated demographic parameters for 25 species of birds inhabiting lowland forests in central Panama. These species were all songbirds (Order Passeriformes) ranging in mass from 7 to 57 g. Using Jolly-Seber stochastic models for open populations, we estimated annual survival rate, population size, and recruitment between sampling periods for each species. We then explored relationships between these parameters and attributes such as body size, phylogenetic affiliation, foraging guild, and social behavior. Larger birds had comparatively long life-spans and low recruitment, but body size was not associated with population size. After adjusting for effects of body size, we found no association between phylogenetic affiliation and any demographic trait. Ecological attributes, especially foraging guild, were more clearly associated with interspecific variation in all demographic traits. Ant-followers had comparatively long life-spans, but species that participate in flocks did not live longer than solitary species. The allometric associations we observed were consistent with those demonstrated in other studies of vertebrates; thus. these relationships appear to be robust. Our finding that ecological factors were more influential than phylogenetic affiliation contrasts with comparative studies of temperate-zone birds and suggests that the relative importance of environmental vs. historical factors varies geographically.

  5. Ecology of invasive mosquitoes: effects on resident species and on human health

    PubMed Central

    Juliano, Steven A.; Lounibos, L. Philip

    2007-01-01

    Investigations of biological invasions focus on patterns and processes that are related to introduction, establishment, spread and impacts of introduced species. This review focuses on the ecological interactions operating during invasions by the most prominent group of insect vectors of disease, mosquitoes. First, we review characteristics of non-native mosquito species that have established viable populations, and those invasive species that have spread widely and had major impacts, testing whether biotic characteristics are associated with the transition from established non-native to invasive. Second, we review the roles of interspecific competition, apparent competition, predation, intraguild predation and climatic limitation as causes of impacts on residents or as barriers to invasion. We concentrate on the best-studied invasive mosquito, Aedes albopictus, evaluating the application of basic ecological theory to invasions by Aedes albopictus. We develop a model based on observations of Aedes albopictus for effects of resource competition and predation as barriers to invasion, evaluating which community and ecosystem characteristics favour invasion. Third, we evaluate the ways in which invasive mosquitoes have contributed to outbreaks of human and animal disease, considering specifically whether invasive mosquitoes create novel health threats, or modify disease transmission for existing pathogen–host systems. PMID:17637849

  6. [Effects of ecological factors on the dough extensograph parameters of different winter wheat cultivars].

    PubMed

    Zhang, Xue-lin; Wang, Chen-yang; Guo, Tian-cai; Wang, Yong-hua; Zhu, Yun-ji

    2009-12-01

    In 2000-2001 and 2001-2002, six representative winter wheat cultivars Yumai 34, Gaomai 8901, Yumai 49, Yumai 70, Luoyang 8716, and Yumai 50 were consecutively grown at five locations (Xinyang, Zhumadian, Xuchang, Wuzhi, and Tangyin) with latitudes varying from 32 degrees N to 36 degrees N in Henan Province, aimed to understand the relationships of winter wheat dough extensograph parameters with genetic and ecological factors. The dough extensograph parameters were more affected by genetic factors than by ecological factors. Cultivars Yumai 34 and Gaomai 8901 had significantly higher maximum resistance and extension area than the other four test cultivars, and significant differences in the dough extensograph parameters were observed between the cultivars grown in the south region (Xinyang and Zhumadian) and in the north region (Wuzhi and Tangyin) of the Province. The change patterns of dough extensograph parameters with latitude differed in 2000-2001 and in 2001-2002, and the effects of climatic factors on the dough extensograph parameters varied with year. In 2001-2002, the precipitation at the stage from grain-filling to maturing affected the dough extensograph parameters significantly. Our results suggested that in order to improve the dough extensograph parameters of winter wheat, local meteorological conditions should be taken into full consideration in the soil water management at late-maturing stage. PMID:20353064

  7. Ecological effects of pharmaceuticals in aquatic systems--impacts through behavioural alterations.

    PubMed

    Brodin, Tomas; Piovano, Susanna; Fick, Jerker; Klaminder, Jonatan; Heynen, Martina; Jonsson, Micael

    2014-11-19

    The study of animal behaviour is important for both ecology and ecotoxicology, yet research in these two fields is currently developing independently. Here, we synthesize the available knowledge on drug-induced behavioural alterations in fish, discuss potential ecological consequences and report results from an experiment in which we quantify both uptake and behavioural impact of a psychiatric drug on a predatory fish (Perca fluviatilis) and its invertebrate prey (Coenagrion hastulatum). We show that perch became more active while damselfly behaviour was unaffected, illustrating that behavioural effects of pharmaceuticals can differ between species. Furthermore, we demonstrate that prey consumption can be an important exposure route as on average 46% of the pharmaceutical in ingested prey accumulated in the predator. This suggests that investigations of exposure through bioconcentration, where trophic interactions and subsequent bioaccumulation of exposed individuals are ignored, underestimate exposure. Wildlife may therefore be exposed to higher levels of behaviourally altering pharmaceuticals than predictions based on commonly used exposure assays and pharmaceutical concentrations found in environmental monitoring programmes. PMID:25405968

  8. Growth response of weed and crop seedlings to deleterious rhizobacteria

    Microsoft Academic Search

    Jianmei Li; Robert J. Kremer

    2006-01-01

    Selected bacterial isolates previously demonstrated to be suppressive toward weed species in the laboratory were tested for effectiveness under greenhouse conditions. Rhizobacteria varied in ability to inhibit growth of host or nonhost weed species. Some bacterial isolates caused ?75% growth inhibition, while some isolates did not express inhibitory effects under greenhouse conditions. Host specificity of rhizobacteria also varied, with some

  9. Evaluating Ecological Effects in a Semi-arid Aquatic System Using Three Lines of Evidence

    NASA Astrophysics Data System (ADS)

    Tardiff, M. F.; Ford-Schmid, R.; Hickmott, D. D.

    2003-12-01

    One mission of Los Alamos National Laboratory has been to develop explosives, machine explosive charges, and test explosive components for the United States nuclear weapons program. Effluents containing high explosives and metals from machining and photographic facilities were discharged to Canon de Valle for forty years at rates up to ten million gallons per year, making up as much as half of the canyon's flow. Discharges to the canyon were discontinued in 1996. Canon de Valle has an interrupted stream that supports an herbaceous ground cover and a multi-layer canopy of conifers, oak and aspen. An ecological screening assessment and problem formulation identified barium, cadmium, copper, manganese and silver as metals of potential ecological concern for the aquatic system in the canyon. Additionally, potential impacts associated with high explosives in the aquatic system are unknown because aquatic community screening values are not available. Two field studies were designed and implemented to assess the adverse effects in the canyon's aquatic system. The first field study consisted of benthic macro-invertebrate surveys that were conducted in Canon de Valle and three reference streams. The survey was then repeated in Canon de Valle four years later to assess trends in the benthic macro-invertebrate community. The second field study consisted of toxicity testing with {it Chironomus tentans} using three locations in the Canon de Valle and one location in a reference canyon. Two rounds of toxicity testing were conducted. Each round was supported with sediment and water sampling at each location for contaminant analysis. The data from the contaminant analysis of water and sediments will be presented along with the results of the benthic macro-invertebrate surveys and the toxicity tests. An example of identifying the contaminants associated with reduced survival in a toxicity test will presented, the utility of benthic macro-invertebrate community metrics as indicators of adverse ecological effects will be discussed, and the relative importance of these three lines of evidence for assessing adverse effects in the canyon's aquatic system will be discussed.

  10. Ecological and biomedical effects of effluents from near-term electric vehicle storage battery cycles

    SciTech Connect

    Not Available

    1980-05-01

    An assessment of the ecological and biomedical effects due to commercialization of storage batteries for electric and hybrid vehicles is given. It deals only with the near-term batteries, namely Pb/acid, Ni/Zn, and Ni/Fe, but the complete battery cycle is considered, i.e., mining and milling of raw materials, manufacture of the batteries, cases and covers; use of the batteries in electric vehicles, including the charge-discharge cycles; recycling of spent batteries; and disposal of nonrecyclable components. The gaseous, liquid, and solid emissions from various phases of the battery cycle are identified. The effluent dispersal in the environment is modeled and ecological effects are assessed in terms of biogeochemical cycles. The metabolic and toxic responses by humans and laboratory animals to constituents of the effluents are discussed. Pertinent environmental and health regulations related to the battery industry are summarized and regulatory implications for large-scale storage battery commercialization are discussed. Each of the seven sections were abstracted and indexed individually for EDB/ERA. Additional information is presented in the seven appendixes entitled; growth rate scenario for lead/acid battery development; changes in battery composition during discharge; dispersion of stack and fugitive emissions from battery-related operations; methodology for estimating population exposure to total suspended particulates and SO/sub 2/ resulting from central power station emissions for the daily battery charging demand of 10,000 electric vehicles; determination of As air emissions from Zn smelting; health effects: research related to EV battery technologies. (JGB)

  11. The toxins of Lyngbya majuscula and their human and ecological health effects.

    PubMed

    Osborne, N J; Webb, P M; Shaw, G R

    2001-11-01

    Lyngbya majuscula is a benthic filamentous marine cyanobacterium, which in recent years appears to have been increasing in frequency and size of blooms in Moreton Bay, Queensland. It has a worldwide distribution throughout the tropics and subtropics in water to 30m. It has been found to contain a variety of chemicals that exert a range of biological effects, including skin, eye and respiratory irritation. The toxins lyngbyatoxin A and debromoaplysiatoxin appear to give the most widely witnessed biological effects in relation to humans, and experiments involving these two toxins show the formation of acute dermal lesions. Studies into the epidemiology of the dermatitic, respiratory and eye effects of the toxins of this organism are reviewed and show that Lyngbya induced dermatitis has occurred in a number of locations. The effects of aerosolised Lyngbya in relation to health outcomes were also reported. Differential effects of bathing behaviour after Lyngbya exposure were examined in relation to the severity of health outcomes. The potential for Lyngbya to exhibit differential toxicologies due to the presence of varying proportions of a range of toxins is also examined. This paper reviews the present state of knowledge on the effects of Lyngbya majuscula on human health, ecosystems and human populations during a toxic cyanobacterial bloom. The potential exists for toxins from Lyngbya majuscula affecting ecological health and in particular marine reptiles. PMID:11757852

  12. The role of deleterious mutations in the stability of hybridogenetic water frog complexes

    PubMed Central

    2014-01-01

    Background Some species of water frogs originated from hybridization between different species. Such hybrid populations have a particular reproduction system called hybridogenesis. In this paper we consider the two species Pelophylax ridibundus and Pelophylax lessonae, and their hybrids Pelophylax esculentus. P. lessonae and P. esculentus form stable complexes (L-E complexes) in which P. esculentus are hemiclonal. In L-E complexes all the transmitted genomes by P. esculentus carry deleterious mutations which are lethal in homozygosity. Results We analyze, by means of an individual based computational model, L-E complexes. The results of simulations based on the model show that, by eliminating deleterious mutations, L-E complexes collapse. In addition, simulations show that particular female preferences can contribute to the diffusion of deleterious mutations among all P. esculentus frogs. Finally, simulations show how L-E complexes react to the introduction of translocated P. ridibundus. Conclusions The conclusions are the following: (i) deleterious mutations (combined with sexual preferences) strongly contribute to the stability of L-E complexes; (ii) female sexual choice can contribute to the diffusion of deleterious mutations; and (iii) the introduction of P. ridibundus can destabilize L-E complexes. PMID:24885008

  13. Ecology 2001 15, 772781

    E-print Network

    Janzen, Fredric

    -words: Chelydra serpentina, maternal behaviour, maternal effects, offspring survival Functional Ecology (2001) 15 in the Common Snapping Turtle, Chelydra serpen- tina. Using eight simultaneous experimental releases of neonates

  14. Ecological effects of a major oil spill on Panamanian coastal marine communities

    SciTech Connect

    Jackson, J.B.C.; Cubit, J.D.; Keller, B.D.; Batista, V.; Burns, K.; Caffey, H.M.; Caldwell, R.L.; Garrity, S.D.; Getter, C.D.; Gonzalez, C.; Guzman, H.M.; Kaufmann, K.W.; Knap, A.H.; Levings, S.C.; Marshall, M.J.; Steger, R.; Thompson, R.C.; Weil, E. (Smithsonian Tropical Research Institute, Balboa (Panama))

    1989-01-06

    In 1986 more than 8 million liters of crude oil spilled into a complex region of mangroves, seagrasses, and coral reefs just east of the Caribbean entrance to the Panama Canal. This was the largest recorded spill into coastal habitats in the tropical Americas. Many populations of plants and animals in both oiled and unoiled sites had been studied previously, thereby providing an unprecedented measure of ecological variation before the spill. Documentation of the spread of oil and its biological effects begun immediately. Intertidal mangroves, seagrasses, algae, and associated invertebrates were covered by oil and died soon after. More surprisingly, there was also extensive mortality of shallow subtidal reef corals and infauna of seagrass beds. After 1.5 years only some organisms in areas exposed to the open sea have recovered.

  15. The Ecological Genetics of Introduced Populations of the Giant Toad BUFO MARINUS. II. Effective Population Size

    PubMed Central

    Easteal, Simon

    1985-01-01

    The allele frequencies are described at ten polymorphic enzyme loci (of a total of 22 loci sampled) in 15 populations of the neotropical giant toad, Bufo marinus, introduced to Hawaii and Australia in the 1930s. The history of establishment of the ten populations is described and used as a framework for the analysis of allele frequency variances. The variances are used to determine the effective sizes of the populations. The estimates obtained (390 and 346) are reasonably precise, homogeneous between localities and much smaller than estimates of neighborhood size obtained previously using ecological methods. This discrepancy is discussed, and it is concluded that the estimates obtained here using genetic methods are the more reliable. PMID:3922852

  16. Causes and ecological effects of resuspended contaminated sediments (RCS) in marine environments.

    PubMed

    Roberts, David A

    2012-04-01

    Sediments act as a net sink for anthropogenic contaminants in marine ecosystems and contaminated sediments may have a range of toxicological effects on benthic fauna and associated species. When resuspended, however, particulate-bound contaminants may be remobilised into the water column and become bioavailable to an additional assemblage of species. Such resuspension occurs through a range of natural and anthropogenic processes each of which may be thought of as pulsed disturbances resulting in pulsed exposures to contaminants. Thus, it is important to understand not only the toxicological responses of organisms to resuspended contaminated sediments (RCS), but also the frequency, magnitude and duration of sediment disturbance events. Such information is rarely collected together with toxicological data. Rather, the majority of published studies (>50% of the articles captured in this review) have taken the form of fixed-duration laboratory-based exposures with individual species. While this research has clearly demonstrated that resuspension of contaminated sediments can liberate sediment-bound contaminants leading to toxicity and bioaccumulation under controlled conditions, the potential for ecological effects in the field is often unclear. Monitoring studies suggest that recurrent natural disturbances such as tides and waves may cause the majority of contaminant release in many environments. However, various processes also act to limit the spatial and temporal scales across which contaminants are remobilised to the most toxic dissolved state. Various natural and anthropogenic disturbances of contaminated sediments have been linked to both community-level and sub-lethal responses in exposed populations of invertebrates and fish in the field. Together these findings suggest that resuspension of contaminated sediments is a frequently recurring ecological threat in contaminated marine habitats. Further consideration of how marine communities respond to temporally variable exposures to RCS is required, as well as research into the relative importance of various disturbances under field conditions. PMID:22244126

  17. Environmental assessment for the satellite power system-concept development and evaluation program-microwave health and ecological effects

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Potential health and ecological effects of the microwave beam from the microwave power transmission system (MPTS) of the satellite power system (SPS) are discussed. A detailed critical review of selected scientific articles from the published literature on the biological effects of nonionizing electromagnetic radiation is provided followed by an assessment of the possible effects of the SPS, based on exposure values for the reference system.

  18. POTENTIAL ECOLOGICAL AND NONTARGET EFFECTS OF TRANSGENIC PLANT GENE PRODUCTS ON AGRICULTURE, SILVICULTURE, AND NATURAL ECOSYSTEMS: GENERAL INTRODUCTION

    EPA Science Inventory

    A symposium was held at the University of Maryland Nov. 30 - Dec. 2, 1992, to discuss transgenic plant risk assessment issues for measurement and identification of potential ecological and nontarget organism effects. he goal was to identify available scientific information and hi...

  19. International Association for Ecology Neighborhood Size in a Beetle Pollinated Tropical Aroid: Effects of Low Density and

    E-print Network

    Thomson, James D.

    - mated from pollinator movements over 3 years in a scarab beetle-pollinated clonai herb, DieffenbachiaInternational Association for Ecology Neighborhood Size in a Beetle Pollinated Tropical Aroid:461-466 (JCCOlOgltt ? Springer-Verlag 1988 Neighborhood size in a beetle pollinated tropical aroid: effects

  20. SHORT-TERM TESTS FOR HEALTH AND ECOLOGICAL EFFECTS. PART 1: PROGRAM OVERVIEW. PART II: DIRECTORY OF TESTS

    EPA Science Inventory

    The report is the proceedings of an Office of Health and Ecological Effects (OHEE), U.S. Environmental Protection Agency workshop held at the Research Triangle Park, North Carolina, in January of 1978. The proceedings consists of eight papers. The first paper is the keynote addre...

  1. DEVELOPMENT OF PROTEIN PROFILE TECHNOLOGY TO EVALUATE ECOLOGICAL EFFECTS OF ENVIRONMENTAL CHEMICALS USING A SMALL FISH MODEL

    EPA Science Inventory

    Hemmer, Michael J., Robert T. Hudson and Calvin C. Walker. In press. Development of Protein Profile Technology to Evaluate Ecological Effects of Environmental Chemicals Using a Small Fish Model (Abstract). To be presented at the EPA Science Forum: Healthy Communities and Ecosyste...

  2. The effect of ecologically relevant variations in light level on the performance of Mongolian gerbils on two visual tasks

    Microsoft Academic Search

    Magdalena E. Krysiak; Kaitlyn R. Bankieris; Qura Abid; Guan Hua Kui; Hillary R. Rodman

    2011-01-01

    Tests of rodent visual capacities are typically performed under standard laboratory illumination. However, light level can have subtle and complex effects on behavior in rodents. We tested Mongolian gerbils (Meriones unguiculatus) – a species that shows individual differences in activity pattern – on visual tasks at three ecologically relevant levels of ambient illuminance: approximating moonlight (1lx), dawn or dusk (10lx),

  3. Lawrence Livermore National Laboratory interests and capabilities for research on the ecological effects of global climatic and atmospheric change

    SciTech Connect

    Amthor, J.S.; Houpis, J.L.; Kercher, J.R.; Ledebuhr, A.; Miller, N.L.; Penner, J.E.; Robison, W.L.; Taylor, K.E.

    1994-09-01

    The Lawrence Livermore National Laboratory (LLNL) has interests and capabilities in all three types of research that must be conducted in order to understand and predict effects of global atmospheric and climatic (i.e., environmental) changes on ecological systems and their functions (ecosystem function is perhaps most conveniently defined as mass and energy exchange and storage). These three types of research are: (1) manipulative experiments with plants and ecosystems; (2) monitoring of present ecosystem, landscape, and global exchanges and pools of energy, elements, and compounds that play important roles in ecosystem function or the physical climate system, and (3) mechanistic (i.e., hierarchic and explanatory) modeling of plant and ecosystem responses to global environmental change. Specific experimental programs, monitoring plans, and modeling activities related to evaluation of ecological effects of global environmental change that are of interest to, and that can be carried out by LLNL scientists are outlined. Several projects have the distinction of integrating modeling with empirical studies resulting in an Integrated Product (a model or set of models) that DOE or any federal policy maker could use to assess ecological effects. The authors note that any scheme for evaluating ecological effects of atmospheric and climatic change should take into account exceptional or sensitive species, in particular, rare, threatened, or endangered species.

  4. There Is Water Everywhere: How News Framing Amplifies the Effect of Ecological Worldviews on Preference for Flooding Protection Policy

    Microsoft Academic Search

    Timothy K. F. Fung; Dominique Brossard; Isabella Ng

    2011-01-01

    The purpose of this study is to examine the interactive effect of worldviews and media frames on policy preference. Using flooding as a case study, we examine the interplay of ecological worldviews and news framed as either emphasizing harmony with nature or mastery over nature on individuals' preference for flood protection policy. A total of 255 undergraduate students participated in

  5. Unexpected Ecological Effects of Distributing the Exotic Weevil, Larinus planus (F.), for the Biological Control of Canada Thistle

    Microsoft Academic Search

    Svaa M. Louda; Charles W. O'Brien

    2002-01-01

    Rhinocyllus conicus , a weevil introduced for biological control of exotic weeds, has had major non- target ecological effects on native thistles. Some practitioners have argued that this is an isolated case. We re- port, however, that another Eurasian weevil ( Larinus planus ), currently being distributed in North America for the control of Canada thistle ( Cirsium arvense ),

  6. DESIGN AND PERFORMANCE OF A FIELD EXPOSURE SYSTEM FOR EVALUATION OF THE ECOLOGICAL EFFECTS OF SO2 ON NATIVE GRASSLAND

    EPA Science Inventory

    The report describes the design and performance of two replicate field exposure systems for evaluating the ecological effects of chronic SO2 exposure on 0.5 ha plots of native Montana grassland. The SO2 was supplied at a constant rate to each plot through a network of 2.5-cm insi...

  7. Evaluation of Ecological Interface Design for Nuclear Process Control: Situation Awareness Effects

    Microsoft Academic Search

    Catherine M. Burns; Gyrd Skraaning Jr.; Greg A. Jamieson; Nathan Lau; Jordanna Kwok; Robin Welch; Gisle Andresen

    2008-01-01

    Objective: We determine whether an ecological interface display for nuclear power plant operations supports improved situation awareness over traditional and user-centered displays in a realistic environment. Background: Ecological interface design (EID) has not yet been fully evaluated with real operators facing realistic scenarios. Method: Ecological displays were evaluated alongside traditional and user-centered “advanced” displays in a full-scope nuclear power plant

  8. The Genomic Load of Deleterious Mutations: Relevance to Death in Infancy and Childhood

    PubMed Central

    Morris, James Alfred

    2015-01-01

    The human diploid genome has approximately 40,000 functioning conserved genes distributed within 6 billion base pairs of DNA. Most individuals carry a few heterozygous deleterious mutations and this leads to an increased risk of recessive disease in the offspring of cousin unions. Rare recessive disease is more common in the children of cousin marriages than in the general population, even though <1% of marriages in the Western World are between first cousins. But more than 90% of the children of cousin marriages do not have recessive disease and are as healthy as the rest of the population. A mathematical model based on these observations generates simultaneous equations linking the mean number of deleterious mutations in the genome of adults (M), the mean number of new deleterious mutations arising in gametogenesis and passed to the next generation (N) and the number of genes in the human diploid genome (L). The best estimates are that M is <7 and N is approximately 1. The nature of meiosis indicates that deleterious mutations in zygotes will have a Poisson distribution with a mean of M?+?N. There must be strong selective pressure against zygotes at the upper end of the Poisson distribution otherwise the value of M would rise with each generation. It is suggested that this selection is based on synergistic interaction of heterozygous deleterious mutations acting in large complex highly redundant and robust genetic networks. To maintain the value of M in single figures over many thousands of generations means that the zygote loss must be of the order of 30%. Most of this loss will occur soon after conception but some will occur later; during fetal development, in infancy and even in childhood. Selection means genetic death and this is caused by disease to which the deleterious mutations predispose. In view of this genome sequencing should be undertaken in all infant deaths in which the cause of death is not ascertained by standard techniques. PMID:25852684

  9. The change of land use and ecological environmental effect in the mining city based on GIS and RS

    NASA Astrophysics Data System (ADS)

    Chen, Qiuji

    2009-10-01

    Land use/cover change (LUCC) research is an important research area of global environment change, but the research on the coal mining area is little. Taking the typical mining city -Jiaozuo City in Henan Province as a case with multi-temporal remote sensing images as major data resources and combining social and economic statistic data, the change of land use of Jiaozuo City in recently ten years was systematically studied, and then the ecological environmental effect caused by land use change was analyzed based on the theories of ecological services value. The research result shows that the condition in mining city was deteriorating and measures shall be taken to improve ecological environment. The studied result can provide scientific basis for ecosystem construction and strategic decisions for sustainable development of mining city.

  10. Predicted no-effect concentrations for mercury species and ecological risk assessment for mercury pollution in aquatic environment.

    PubMed

    Du, Meng; Wei, Dongbin; Tan, Zhuowei; Lin, Aiwu; Du, Yuguo

    2015-02-01

    Mercury (Hg) exists in different chemical forms presenting varied toxic potentials. It is necessary to explore an ecological risk assessment method for different mercury species in aquatic environment. The predicted no-effect concentrations (PNECs) for Hg(II) and methyl mercury (MeHg) in the aqueous phase, calculated using the species sensitivity distribution method and the assessment factor method, were 0.39 and 6.5×10(-3)?g/L, respectively. The partition theory of Hg between sediment and aqueous phases was considered, along with PNECs for the aqueous phase to conduct an ecological risk assessment for Hg in the sediment phase. Two case studies, one in China and one in the Western Black Sea, were conducted using these PNECs. The toxicity of mercury is heavily dependent on their forms, and their potential ecological risk should be respectively evaluated on the basis of mercury species. PMID:25662241

  11. Ecological effects and animal risk assessment of radiation pollution in Russia and former USSR

    SciTech Connect

    Krivolutsky, D. [Russian Academy of Sciences, Moscow (Russian Federation). Inst. of Ecology and Evolution Problems

    1995-12-31

    The ecological after-effects of long-term radiation pollution, animal biodiversity changes and life-cycle assessment of model species of soil invertebrates mammals, birds, reptiles have been studied in 1968-1994 in the former USSR (Russia, Ukraine, Kazachstan). There has been observed an initial reduction of animal biodiversity community structure in Kyshtym (south Ural) and Chernobyl polluted areas and a low return to the former ecosystems. The secondary changes and side-effects for the active migrants (insects, birds, mammals) have been registered. The most valid bioindicators and biomarkers of radioactive pollution may be stable populations of reptiles, birds, earthworms, centipede, microarthropods. The radioactive soil pollution exerts the greatest impact on the permanent soil dwelling animals. As direct effects it has been seen the appreciable reduction of population density disturbance of the breeding process, degradation of species diversity community structure. In fact a soil with high level {sup 90}Sr and a radiation 1--3 R/day containing 10-fold reduction of population soil inhabit millipedes earthworms, insect larvae, Enchytraeidae aranea. The accumulation of radionuclides by terrestrial and soil animals effects of trophic levels, zoogenical radionuclides migration have been studied in polluted ecosystems of South Ural and Chernobyl.

  12. Ecology, Microbial

    SciTech Connect

    Konopka, Allan

    2009-03-19

    Microbial ecology is a relatively young discipline within the field of microbiology. Its modern history spans just the past 60 years, and the field is defined by its emphasis on understanding the interactions of microbes with their environment, rather than their behavior under artificial laboratory conditions. Because microbes are ubiquitous, microbial ecologists study a broad diversity of habitats that range from aquatic to terrestrial to plant- or animal-associated. This has made it a challenge to identify unifying principles within the field. One approach is to recognize that although the activity of microbes in nature have effects at the macroscale, they interact with their physical, chemical and biological milieu at a scale of micrometers. At this scale, several different microbial ecosystems can be defined, based upon association with particles, the presence of environmental gradients and the continuous availability of water. Principles applicable to microbial ecology reflect not only their population ecology and physiological ecology, but also their broad versatility and quantitative importance in the biosphere as biogeochemical catalysts and capacity for rapid physiological and evolutionary responses.

  13. Ecology, Microbial

    SciTech Connect

    Konopka, Allan

    2009-05-15

    Microbial ecology is a relatively young discipline within the field of microbiology. Its modern history spans just the past 60 years, and the field is defined by its emphasis on understanding the interactions of microbes with their environment, rather than their behavior under artificial laboratory conditions. Because microbes are ubiquitous, microbial ecologists study a broad diversity of habitats that range from aquatic to terrestrial to plant- or animal-associated. This has made it a challenge to identify unifying principles within the field. One approach is to recognize that although the activity of microbes in nature have effects at the macroscale, they interact with their physical, chemical and biological milieu at a scale of micrometers. At this scale, several different microbial ecosystems can be defined, based upon association with particles, the presence of environmental gradients and the continuous availability of water. Principles applicable to microbial ecology reflect not only their population ecology and physiological ecology, but also their broad versatility and quantitative importance in the biosphere as biogeochemical catalysts and capacity for rapid physiological and evolutionary responses.

  14. Effective sociodemographic population assessment of elusive species in ecology and conservation management.

    PubMed

    Head, Josephine S; Boesch, Christophe; Robbins, Martha M; Rabanal, Luisa I; Makaga, Loïc; Kühl, Hjalmar S

    2013-09-01

    Wildlife managers are urgently searching for improved sociodemographic population assessment methods to evaluate the effectiveness of implemented conservation activities. These need to be inexpensive, appropriate for a wide spectrum of species and straightforward to apply by local staff members with minimal training. Furthermore, conservation management would benefit from single approaches which cover many aspects of population assessment beyond only density estimates, to include for instance social and demographic structure, movement patterns, or species interactions. Remote camera traps have traditionally been used to measure species richness. Currently, there is a rapid move toward using remote camera trapping in density estimation, community ecology, and conservation management. Here, we demonstrate such comprehensive population assessment by linking remote video trapping, spatially explicit capture-recapture (SECR) techniques, and other methods. We apply it to three species: chimpanzees Pan troglodytes troglodytes, gorillas Gorilla gorilla gorilla, and forest elephants Loxodonta cyclotis in Loango National Park, Gabon. All three species exhibited considerable heterogeneity in capture probability at the sex or group level and density was estimated at 1.72, 1.2, and 1.37 individuals per km(2) and male to female sex ratios were 1:2.1, 1:3.2, and 1:2 for chimpanzees, gorillas, and elephants, respectively. Association patterns revealed four, eight, and 18 independent social groups of chimpanzees, gorillas, and elephants, respectively: key information for both conservation management and studies on the species' ecology. Additionally, there was evidence of resident and nonresident elephants within the study area and intersexual variation in home range size among elephants but not chimpanzees. Our study highlights the potential of combining camera trapping and SECR methods in conducting detailed population assessments that go far beyond documenting species diversity patterns or estimating single species population size. Our study design is widely applicable to other species and spatial scales, and moderately trained staff members can collect and process the required data. Furthermore, assessments using the same method can be extended to include several other ecological, behavioral, and demographic aspects: fission and fusion dynamics and intergroup transfers, birth and mortality rates, species interactions, and ranging patterns. PMID:24101982

  15. Administrative Ecology

    ERIC Educational Resources Information Center

    McGarity, Augustus C., III; Maulding, Wanda

    2007-01-01

    This article discusses how all four facets of administrative ecology help dispel the claims about the "impossibility" of the superintendency. These are personal ecology, professional ecology, organizational ecology, and community ecology. Using today's superintendency as an administrative platform, current literature describes a preponderance of…

  16. A review of fire effects on vegetation and soils in the Great Basin region: response and ecological site characteristics

    USGS Publications Warehouse

    Miller, Richard F.; Chambers, Jeanne C.; Pyke, David A.; Pierson, Fred B.; Williams, C. Jason

    2013-01-01

    This review synthesizes the state of knowledge on fire effects on vegetation and soils in semi-arid ecosystems in the Great Basin Region, including the central and northern Great Basin and Range, Columbia River Basin, and the Snake River Plain. We summarize available literature related to: (1) the effects of environmental gradients, ecological site, and vegetation characteristics on resilience to disturbance and resistance to invasive species; (2) the effects of fire on individual plant species and communities, biological soil crusts, seed banks, soil nutrients, and hydrology; and (3) the role of fire severity, fire versus fire surrogate treatments, and post-fire grazing in determining ecosystem response. From this, we identify knowledge gaps and present a framework for predicting plant successional trajectories following wild and prescribed fires and fire surrogate treatments. Possibly the three most important ecological site characteristics that influence a site’s resilience (ability of the ecological site to recover from disturbance) and resistance to invasive species are soil temperature/moisture regimes and the composition and structure of vegetation on the ecological site just prior to the disturbance event.

  17. Ecology of Harmful Algae

    NASA Astrophysics Data System (ADS)

    Roelke, Daniel L.

    2007-07-01

    Edna Graneli and Jefferson T. Turner, Editors;Ecological Studies Series, Vol. 189; Springer; ISBN 3540322094; 413 pp.; 2006; $195 Harmful algal blooms (HABs) affect commercially and recreationally important species, human health, and ecosystem functioning. Hallmark events are the visually stunning blooms where waters are discolored and filled with ichthyotoxin-producing algae that lead to large fish kills. Of most concern, however, are HABs that pose a threat to human health. For example, some phycotoxins bioaccumulate in the guts and tissues of commercially and recreationally important species that when consumed by humans, may result in nausea, paralysis, memory loss, and even death. In addition to the deleterious impacts of phycotoxins, HABs can be problematic in other ways. For example, the decay of blooms often leads to low dissolved oxygen in subsurface waters. Blooms also reduce light penetration into the water column. Both processes disrupt ecosystems and in some cases have completely destroyed benthic communities.

  18. Divergent ecological effects of oceanographic anomalies on terrestrial ecosystems of the Mexican Pacific coast

    PubMed Central

    Caso, Margarita; González-Abraham, Charlotte; Ezcurra, Exequiel

    2007-01-01

    Precipitation pulses are essential for the regeneration of drylands and have been shown to be related to oceanographic anomalies. However, whereas some studies report increased precipitation in drylands in northern Mexico during El Niño years, others report increased drought in the southern drylands. To elucidate the effect of oceanographic/atmospheric anomalies on moisture pulses along the whole Pacific coast of Mexico, we correlated the average Southern Oscillation Index values with total annual precipitation for 117 weather stations. We also analyzed this relationship for three separate rainfall signals: winter-spring, summer monsoon, and fall precipitation. The results showed a distinct but divergent seasonal pattern: El Niño events tend to bring increased rainfall in the Mexican northwest but tend to increase aridity in the ecosystems of the southern tropical Pacific slope. The analysis for the separated rainfall seasons showed that El Niño conditions produce a marked increase in winter rainfall above 22° latitude, whereas La Niña conditions tend to produce an increase in the summer monsoon-type rainfall that predominates in the tropical south. Because these dryland ecosystems are dependent on rainfall pulses for their renewal, understanding the complex effect of ocean conditions may be critical for their management in the future. Restoration ecology, grazing regimes, carrying capacities, fire risks, and continental runoff into the oceans could be predicted from oceanographic conditions. Monitoring the coupled atmosphere–ocean system may prove to be important in managing and mitigating the effects of large-scale climatic change on coastal drylands in the future. PMID:17563355

  19. Ecological contingency in the effects of climatic warming on forest herb communities

    PubMed Central

    Harrison, Susan; Damschen, Ellen I.; Grace, James B.

    2010-01-01

    Downscaling from the predictions of general climate models is critical to current strategies for mitigating species loss caused by climate change. A key impediment to this downscaling is that we lack a fully developed understanding of how variation in physical, biological, or land-use characteristics mediates the effects of climate change on ecological communities within regions. We analyzed change in understory herb communities over a 60-y period (1949/1951–2007/2009) in a complex montane landscape (the Siskiyou Mountains, Oregon) where mean temperatures have increased 2 °C since 1948, similar to projections for other terrestrial communities. Our 185 sites included primary and secondary-growth lower montane forests (500–1.200 m above sea level) and primary upper montane to subalpine forests (1,500–2,100 m above sea level). In lower montane forests, regardless of land-use history, we found multiple herb-community changes consistent with an effectively drier climate, including lower mean specific leaf area, lower relative cover by species of northern biogeographic affinity, and greater compositional resemblance to communities in southerly topographic positions. At higher elevations we found qualitatively different and more modest changes, including increases in herbs of northern biogeographic affinity and in forest canopy cover. Our results provide community-level validation of predicted nonlinearities in climate change effects. PMID:20974978

  20. Pelagic habitat of seabirds in the eastern tropical Pacific: effects of foraging ecology on habitat selection

    Microsoft Academic Search

    L. Ignacio Vilchis; Lisa T. Ballance; Paul C. Fiedler

    2006-01-01

    A central tenet of ecology is the quantification of species-habitat relationships in order to explain spatial variability in the distribution and abundance patterns of animals. We quantified habitat preferences for 6 tropical seabird species representing a phylogenetically and ecologically diverse group within the eastern tropical Pacific (ETP). Seabird censuses were conducted aboard NOAA research vessels from August to November of

  1. Effects of ecological compensation meadows on arthropod diversity in adjacent intensively managed grassland

    Microsoft Academic Search

    Matthias Albrecht; Bernhard Schmid; Martin K. Obrist; Beatrice Schüpbach; David Kleijn; Peter Duelli

    2010-01-01

    An important goal of ecological compensation areas (ECAs) is to increase biodiversity in adjacent intensively managed farmland and the agricultural landscape at large. We tested whether this goal can be achieved in the case of the agri-environmental restoration scheme implemented for Swiss grassland using five large arthropod taxa (bees, true bugs, orthopterans, ground beetles and spiders) representing different ecological and

  2. Human Ecology Human ecology Research

    E-print Network

    Wang, Z. Jane

    Human Ecology Impact of Human ecology Research Bonus Issue FROM SCHOLARSHIP TO POLICY MAKING OF HUMAN ECOLOGY APRIL 2005/VOLUME 33, NUMBER 1 #12;Human Ecology Volume 33, Number 1 April 2005 The New York State College of Human Ecology at Cornell University Lisa Staiano-Coico, Ph.D. Rebecca Q

  3. White Paper: Summary of the NOAA Workshop - Ecological Effect of Sea Level Rise in the Florida Panhandle and Coastal Alabama: Research and Modeling Needs

    EPA Science Inventory

    The Center for Sponsored Coastal Ocean Research (CSCOR) is addressing current and future impacts to ecological systems due to the long term effect of sea level rise due to climate change and subsidence on coastal ecosystems through the peer-reviewed research program, the Ecologic...

  4. Recurrent loss of sex is associated with accumulation of deleterious mutations in oenothera.

    PubMed

    Hollister, Jesse D; Greiner, Stephan; Wang, Wei; Wang, Jun; Zhang, Yong; Wong, Gane Ka-Shu; Wright, Stephen I; Johnson, Marc T J

    2015-04-01

    Sexual reproduction is nearly universal among eukaryotes. Theory predicts that the rarity of asexual eukaryotic species is in part caused by accumulation of deleterious mutations and heightened extinction risk associated with suppressed recombination and segregation in asexual species. We tested this prediction with a large data set of 62 transcriptomes from 29 species in the plant genus Oenothera, spanning ten independent transitions between sexual and a functionally asexual genetic system called permanent translocation heterozygosity. Illumina short-read sequencing and de novo transcript assembly yielded an average of 16.4 Mb of sequence per individual. Here, we show that functionally asexual species accumulate more deleterious mutations than sexual species using both population genomic and phylogenetic analysis. At an individual level, asexual species exhibited 1.8× higher heterozygosity than sexual species. Within species, we detected a higher proportion of nonsynonymous polymorphism relative to synonymous variation within asexual compared with sexual species, indicating reduced efficacy of purifying selection. Asexual species also exhibited a greater proportion of transcripts with premature stop codons. The increased proportion of nonsynonymous mutations was also positively correlated with divergence time between sexual and asexual species, consistent with Muller's ratchet. Between species, we detected repeated increases in the ratio of nonsynonymous to synonymous divergence in asexual species compared with sexually reproducing sister taxa, indicating increased accumulation of deleterious mutations. These results confirm that an important advantage of sex is that it facilitates selection against deleterious alleles, which might help to explain the dearth of extant asexual species. PMID:25534028

  5. DELETERIOUS MUTATIONS AS AN EVOLUTIONARY FACTOR. 11. FACULTATIVE APOMIXIS AND SELFING

    Microsoft Academic Search

    ALEXEY S. KONDRASHOV

    A population with U deleterious mutations per genome per generation is considered in which only those individuals that carry less than a critical number K of mutations are viable. Besides a large number of loci subject to mutation and selection, the genome contains one or two special loci responsible for the mode of reproduction. Amphimixis us. apomixis and amphimixis us.

  6. Direct estimation of per nucleotide and genomic deleterious mutation rates in Drosophila

    E-print Network

    Keightley, Peter

    LETTERS Direct estimation of per nucleotide and genomic deleterious mutation rates in Drosophila sequences5 and fitness traits are discordant6­8 . Here we directly estimate u in Drosophila melanogaster , Brian Charlesworth1 & Peter D. Keightley1 Spontaneous mutations are the source of genetic variation

  7. Copyright 1998 by the Genetics Society of America Testing for Epistasis Between Deleterious Mutations

    E-print Network

    West, Stuart

    Copyright © 1998 by the Genetics Society of America Testing for Epistasis Between Deleterious leads to a greater decrease in log fitness than the last (synergistic epistasis), then the evolution, there is a severe shortage of relevant data. Three relatively simple experimental methods to test for epistasis

  8. Parasites and deleterious mutations: interactions influencing the evolutionary maintenance of sex

    E-print Network

    hypothesis (Kondrashov, 1988, 1993), requires synergistic epistasis among deleterious muta- tions. However, experimental tests for epistasis in a range of taxa show that this is by no means a common situation (de al., 2005; Martin et al., 2007). Often no epistasis or antagonistic epistasis is observed and

  9. A Dietary Test of Putative Deleterious Sterols for the Aphid Myzus persicae

    E-print Network

    Behmer, Spencer T.

    A Dietary Test of Putative Deleterious Sterols for the Aphid Myzus persicae Sophie Bouvaine1, College Station, Texas, United States of America Abstract The aphid Myzus persicae displays high mortality resistance to the aphids, M. persicae were reared on chemically-defined diets with different steroid contents

  10. Macrophage Migration Inhibitory Factor Inhibition Is Deleterious for High-Fat Diet-Induced Cardiac Dysfunction

    PubMed Central

    Montaigne, David; Marechal, Xavier; Ballot, Caroline; Hassoun, Sidi Mohamed; Decoster, Brigitte; Neviere, Remi; Lancel, Steve

    2013-01-01

    Aims Development of metabolic syndrome is associated with impaired cardiac performance, mitochondrial dysfunction and pro-inflammatory cytokine increase, such as the macrophage migration inhibitory factor MIF. Depending on conditions, MIF may exert both beneficial and deleterious effects on the myocardium. Therefore, we tested whether pharmacological inhibition of MIF prevented or worsened metabolic syndrome-induced myocardial dysfunction. Methods and Results C57BL/6J mice were fed for ten weeks with 60% fat-enriched diet (HFD) or normal diet (ND). MIF inhibition was obtained by injecting mice twice a week with ISO-1, for three consecutive weeks. Then, triglycerides, cholesterol, fat mass, glucose intolerance, insulin resistance, ex vivo cardiac contractility, animal energetic substrate utilization assessed by indirect calorimetry and mitochondrial respiration and biogenesis were evaluated. HFD led to fat mass increase, dyslipidemia, glucose intolerance and insulin resistance. ISO-1 did not alter these parameters. However, MIF inhibition was responsible for HFD-induced cardiac dysfunction worsening. Mouse capacity to increase oxygen consumption in response to exercise was reduced in HFD compared to ND, and further diminished in ISO-1-treated HFD group. Mitochondrial respiration was reduced in HFD mice, treated or not with ISO-1. Compared to ND, mitochondrial biogenesis signaling was upregulated in the HFD as demonstrated by mitochondrial DNA amount and PGC-1? expression. However, this increase in biogenesis was blocked by ISO-1 treatment. Conclusion MIF inhibition achieved by ISO-1 was responsible for a reduction in HFD-induced mitochondrial biogenesis signaling that could explain majored cardiac dysfunction observed in HFD mice treated with MIF inhibitor. PMID:23536817

  11. Malarial pathocoenosis: beneficial and deleterious interactions between malaria and other human diseases

    PubMed Central

    Faure, Eric

    2014-01-01

    In nature, organisms are commonly infected by an assemblage of different parasite species or by genetically distinct parasite strains that interact in complex ways. Linked to co-infections, pathocoenosis, a term proposed by M. Grmek in 1969, refers to a pathological state arising from the interactions of diseases within a population and to the temporal and spatial dynamics of all of the diseases. In the long run, malaria was certainly one of the most important component of past pathocoenoses. Today this disease, which affects hundreds of millions of individuals and results in approximately one million deaths each year, is always highly endemic in over 20% of the world and is thus co-endemic with many other diseases. Therefore, the incidences of co-infections and possible direct and indirect interactions with Plasmodium parasites are very high. Both positive and negative interactions between malaria and other diseases caused by parasites belonging to numerous taxa have been described and in some cases, malaria may modify the process of another disease without being affected itself. Interactions include those observed during voluntary malarial infections intended to cure neuro-syphilis or during the enhanced activations of bacterial gastro-intestinal diseases and HIV infections. Complex relationships with multiple effects should also be considered, such as those observed during helminth infections. Moreover, reports dating back over 2000 years suggested that co- and multiple infections have generally deleterious consequences and analyses of historical texts indicated that malaria might exacerbate both plague and cholera, among other diseases. Possible biases affecting the research of etiological agents caused by the protean manifestations of malaria are discussed. A better understanding of the manner by which pathogens, particularly Plasmodium, modulate immune responses is particularly important for the diagnosis, cure, and control of diseases in human populations. PMID:25484866

  12. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids.

    PubMed

    Singh, Akanksha; Braun, Julia; Decker, Emilia; Hans, Sarah; Wagner, Agnes; Weisser, Wolfgang W; Zytynska, Sharon E

    2014-10-21

    BackgroundInteractions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations.ResultsOur data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass.ConclusionsPrevious work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved. PMID:25331082

  13. Plant volatile organic compounds (VOCs) in ozone (O3) polluted atmospheres: the ecological effects.

    PubMed

    Pinto, Delia M; Blande, James D; Souza, Silvia R; Nerg, Anne-Marja; Holopainen, Jarmo K

    2010-01-01

    Tropospheric ozone (O3) is an important secondary air pollutant formed as a result of photochemical reactions between primary pollutants, such as nitrogen oxides (NOx), and volatile organic compounds (VOCs). O3 concentrations in the lower atmosphere (troposphere) are predicted to continue increasing as a result of anthropogenic activity, which will impact strongly on wild and cultivated plants. O3 affects photosynthesis and induces the development of visible foliar injuries, which are the result of genetically controlled programmed cell death. It also activates many plant defense responses, including the emission of phytogenic VOCs. Plant emitted VOCs play a role in many eco-physiological functions. Besides protecting the plant from abiotic stresses (high temperatures and oxidative stress) and biotic stressors (competing plants, micro- and macroorganisms), they drive multitrophic interactions between plants, herbivores and their natural enemies e.g., predators and parasitoids as well as interactions between plants (plant-to-plant communication). In addition, VOCs have an important role in atmospheric chemistry. They are O3 precursors, but at the same time are readily oxidized by O3, thus resulting in a series of new compounds that include secondary organic aerosols (SOAs). Here, we review the effects of O3 on plants and their VOC emissions. We also review the state of current knowledge on the effects of ozone on ecological interactions based on VOC signaling, and propose further research directions. PMID:20084432

  14. The Study on Ecological Treatment of Saline Lands to Mitigate the Effects of Climate Change

    NASA Astrophysics Data System (ADS)

    Xie, Jiancang; Zhu, Jiwei; Wang, Tao

    2010-05-01

    The soil water and salt movement is influenced strongly by the frequent droughts, floods and climate change. Additionally, as continued population growth, large-scale reclaiming of arable land and long-term unreasonable irrigation, saline land is increasing at the rate of 1,000,000~15,000,000 mu each year all over the world. In the tradition management, " drainage as the main " measure has series of problem, which appears greater project, more occupation of land, harmful for water saving and downstream pollution. To response the global climate change, it has become the common understanding, which promote energy-saving and environment protection, reflect the current model, explore the ecological management model. In this paper, we take severe saline land—Lubotan in Shaanxi Province as an example. Through nearly 10 years harnessing practice and observing to meteorology, hydrology, soil indicators of climate, we analyze the influence of climate change to soil salinity movement at different seasons and years, then put forward and apply a new model of saline land harnessing to mitigate the Effects of Climate Change and self-rehabilitate entironment. This model will be changed "drainage" to "storage", through the establishment engineering of " storage as the main ", taken comprehensive measures of " project - biology - agriculture ", we are changing saline land into arable land. Adapted to natural changes of climate, rainfall, irrigation backwater, groundwater level, reduced human intervention to achieve system dynamic equilibrium. During the ten years, the salt of plough horizon has reduced from 0.74% to 0.20%, organic matter has increased from 0.7% to 0.92%, various indicators of soil is begining to go better. At the same time, reduced the water for irrigation, drainage pollution and investment costs. Through the model, reformed severe saline land 18,900 mu, increased new cultivated land 16,500 mu, comprehensive efficient significant, ensured the coordinated development of " water - biology - environment " in the region. Model application and promotion can treat saline-alkali and add cultivated land effectively, at the same time, ease the pressure for urban construction land, promote energy saving and emission reducting and ecological restoration, so we can construct a resource-saving and environment-friendly society, realize sustainable development of the population, resources and environment.

  15. Effect of dissolved humic acid on the Pb bioavailability in soil solution and its consequence on ecological risk.

    PubMed

    An, Jinsung; Jho, Eun Hea; Nam, Kyoungphile

    2015-04-01

    Current risk characterization in ecological risk assessment does not consider bioavailability of heavy metals, which highly depends on physicochemical properties of environmental media. This study was set to investigate the effect of humic acid (HA), used as a surrogate of organic matter, on Pb toxicity and the subsequent effect on risk characterization in ecological risk assessment. Pb toxicity was assessed using Microtox(®) in the presence and absence of two different forms of HA, particulate HA (pHA) and dissolved HA (dHA). With increasing contact time, the EC10 values increased (i.e., the toxic effects decreased) and the dissolved Pb concentrations of the filtrates decreased. The high correlation (R=0.88, p<0.001) between toxic effects determined using both the mixture and its filtrate as exposure media leads us to conclude that the Pb toxicity highly depends on the soluble fraction. Also, reduced Pb toxicity with increasing dHA concentrations, probably due to formation of Pb-dHA complexes, indicated that Pb toxicity largely comes from free Pb ions. Overall, this study shows the effect of HA on metal toxicity alleviation, and emphasizes the need for incorporating the bioavailable heavy metal concentrations in environmental media as a point of exposure in ecological risk assessment. PMID:25590817

  16. Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment.

    PubMed

    Camargo, Julio A; Alonso, Alvaro

    2006-08-01

    We provide a global assessment, with detailed multi-scale data, of the ecological and toxicological effects generated by inorganic nitrogen pollution in aquatic ecosystems. Our synthesis of the published scientific literature shows three major environmental problems: (1) it can increase the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) it can stimulate or enhance the development, maintenance and proliferation of primary producers, resulting in eutrophication of aquatic ecosystems; (3) it can reach toxic levels that impair the ability of aquatic animals to survive, grow and reproduce. Inorganic nitrogen pollution of ground and surface waters can also induce adverse effects on human health and economy. Because reductions in SO2 emissions have reduced the atmospheric deposition of H2SO4 across large portions of North America and Europe, while emissions of NOx have gone unchecked, HNO3 is now playing an increasing role in the acidification of freshwater ecosystems. This acidification process has caused several adverse effects on primary and secondary producers, with significant biotic impoverishments, particularly concerning invertebrates and fishes, in many atmospherically acidified lakes and streams. The cultural eutrophication of freshwater, estuarine, and coastal marine ecosystems can cause ecological and toxicological effects that are either directly or indirectly related to the proliferation of primary producers. Extensive kills of both invertebrates and fishes are probably the most dramatic manifestation of hypoxia (or anoxia) in eutrophic and hypereutrophic aquatic ecosystems with low water turnover rates. The decline in dissolved oxygen concentrations can also promote the formation of reduced compounds, such as hydrogen sulphide, resulting in higher adverse (toxic) effects on aquatic animals. Additionally, the occurrence of toxic algae can significantly contribute to the extensive kills of aquatic animals. Cyanobacteria, dinoflagellates and diatoms appear to be major responsible that may be stimulated by inorganic nitrogen pollution. Among the different inorganic nitrogenous compounds (NH4+, NH3, NO2-, HNO2NO3-) that aquatic animals can take up directly from the ambient water, unionized ammonia is the most toxic, while ammonium and nitrate ions are the least toxic. In general, seawater animals seem to be more tolerant to the toxicity of inorganic nitrogenous compounds than freshwater animals, probably because of the ameliorating effect of water salinity (sodium, chloride, calcium and other ions) on the tolerance of aquatic animals. Ingested nitrites and nitrates from polluted drinking waters can induce methemoglobinemia in humans, particularly in young infants, by blocking the oxygen-carrying capacity of hemoglobin. Ingested nitrites and nitrates also have a potential role in developing cancers of the digestive tract through their contribution to the formation of nitrosamines. In addition, some scientific evidences suggest that ingested nitrites and nitrates might result in mutagenicity, teratogenicity and birth defects, contribute to the risks of non-Hodgkin's lymphoma and bladder and ovarian cancers, play a role in the etiology of insulin-dependent diabetes mellitus and in the development of thyroid hypertrophy, or cause spontaneous abortions and respiratory tract infections. Indirect health hazards can occur as a consequence of algal toxins, causing nausea, vomiting, diarrhoea, pneumonia, gastroenteritis, hepatoenteritis, muscular cramps, and several poisoning syndromes (paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning). Other indirect health hazards can also come from the potential relationship between inorganic nitrogen pollution and human infectious diseases (malaria, cholera). Human sickness and death, extensive kills of aquatic animals, and other negative effects, can have elevated costs on human economy, with the recreation and tourism industry suffering the most impo

  17. [Occurrence form and ecological effect of selenium in soil and surface water of Kailuan Coalfield of Tangshan].

    PubMed

    Zhang, Xiu-Zhi; Ma, Zhong-She; Wang, Yin-Nan; Wang, Zhi-Jun; Xie, Wei-Ming

    2012-10-01

    Mining induced generally adverse effect to the environmental ecosystems. This paper studied the beneficial element Se produced in the process of coal mining and burning. The occurrence form of Se in soil and surface water influx into the mine water and the enrichment of Se by crops such as wheat, maize and rice were analyzed. The results indicated that organic and residual forms are the dominant forms of Se in soil, with the soluble form accounting for only 1%. Se4+ and Se6+ accounted for 23.89% and 32.99% in total soluble Se in soil, respectively. In the surface water influx into the mine water, the percentages were 37.78% and 40.24%, respectively. The mean contents of Se in wheat, maize and rice were 0.169 mg x kg(-1), 0.094 mg x kg(-1) and 0.26 mg x kg(-1), respectively. Rice was irrigated using the mine water, which did not only solve the problem of waste water, but also produced Se-enriched rice, moreover, the contents of deleterious elements were not high. Therefore, making full use of the Se-enriched resource in the mining area would weaken the adverse effect of mining. PMID:23233966

  18. The Ecological Road-Effect Zone of a Massachusetts (U.S.A.) Suburban Highway

    Microsoft Academic Search

    Richard T. T. Forman; Robert D. Deblinger

    2000-01-01

    Ecological flows and biological diversity trace broad patterns across the landscape, whereas trans- portation planning for human mobility traditionally focuses on a narrow strip close to a road or highway. To help close this gap we examined the \\

  19. POPULATION ECOLOGY Interactions of Elevated CO2 and Nitrogen Fertilization: Effects on

    E-print Network

    Trumble, John T.

    for agricultural use of transgenic plants, but also for the ecological consequences of transfer of Bt toxins, CO2, cotton ATMOSPHERIC CARBON DIOXIDE levels have increased from 270 to 280 l/liter in preindustrial

  20. DESIGN OF FIELD EXPERIMENTS TO DETERMINE THE ECOLOGICAL EFFECTS OF PETROLEUM IN INTERTIDAL ECOSYSTEMS

    EPA Science Inventory

    Is it possible to design field experiments that will yield ecologically and statistically significant information about how oil affects intertidal ecosystems. What classes of experimental design and technical approach are most likely to generate optimal information on these effec...

  1. Evolutionary Ecology, 1992, 6, 360-382 Evolution in heterogeneous environments" effects of

    E-print Network

    Brown, Joel S.

    in the adaptive surface to occupy new peaks (hence, Sewell Wright's shifting balance theory). Frequency to occupy both peaks. Keywords: habitat selection; migration; ESS; fitness set; frequency-dependent selection; evolution of specialization; landscape ecology; adaptive surface Introduction Evolutionary

  2. Significance and effect of ecological rehabilitation project in inland river basins in northwest China.

    PubMed

    Wang, Yu; Feng, Qi; Chen, Lijuan; Yu, Tengfei

    2013-07-01

    The Ecological Water Transfer and Rehabilitation Project in the arid inland area of northwest China is an important measure in restoring a deteriorated ecosystem. However, the sustainability of the project is affected by many socio-economic factors. This article examines the attitudes of the local populace toward the project, its impact on the livelihood of the people, and the positive effects of water-efficient agricultural practices in Ejina County. Related data were collected through questionnaire surveys and group discussions. The results identified three critical issues that may influence the sustainability of the project in the study area. The first issue relates to the impact of the project on the livelihood of local herdsmen. The potential for the sustainability of the project is compromised because the livelihood of the herdsmen greatly depends on the compensation awarded by the project. The second issue is that the project did not raise the water resource utilization ratio, which may undermine its final purpose. Finally, the compensation provided by the project considers losses in agriculture, but neglects the externalities and public benefit of eco-water. Thus, appropriate compensation mechanisms should be established and adopted according to local economic, environmental, and social conditions. Some recommendations for improving the sustainability of the project are provided based on the results of this study. PMID:23716005

  3. Proximal ecological effects of the 1980 eruptions of Mount St. Helens

    NASA Technical Reports Server (NTRS)

    Swanson, F. J.

    1988-01-01

    The diversity of ecosystems and volcanic processes involved in the 1980 eruptions of Mount St. Helens, southwest Washington, provide an excellent setting for examining effects of volcanic events on ecosystems. These eruptions included a lateral blast, debris avalanche, mudflows, pyroclastic flows, and airfall tephra. Affected ecosystems within 30 km of the vent were lakes, streams, upland and riparian forest, and meadows. Ecological disturbances imposed by the Mount St. Helens events were predominantly physical, rather than climatic or chemical which are the dominant classes of disturbances considered in analysis of global catastrophes. Analysis of ecosystem response to disturbance should be based on consideration of composition and structure of the predisturbance system in terms that represent potential survivability of organisms, mechanisms in the primary disturbance, initial survivors, secondary disturbances arising from the primary disturbance and the biological responses to secondary disturbances, invasion of the site by new propagules, interactions among secondary disturbance processes and surviving and invading organisms. Predicting ecosystem response to disturbance is enchanced by considering the mechanisms of disturbance rather than type of disturbance. In the 1980 Mount St. Helens events, the disturbance types, involved primarily the mechanisms of sedimentation, heating, and shear stress. Each disturbance type involved one or more mechanisms. Ecosystem response varied greatly across the landscape. Analysis of ecosystem response to disturbance, regardless of type, should include detailed consideration of the properties of individual species, primary and secondary disturbance mechanisms, and their distributions across landscapes.

  4. Ecological effects of contaminants in McCoy Branch, 1991--1993

    SciTech Connect

    Ryon, M.G. [ed.] [ed.

    1996-09-01

    The 1984 Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA) required assessment of all current and former solid waste management units. Following guidelines under RCRA and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), a remedial investigation (RI) was required of the Y-12 Plant for their filled coal ash pond (FCAP) and associated areas on McCoy Branch. The RI process was initiated and assessments were presented. Because the disposal of coal ash in the ash pond, McCoy Branch, and Rogers Quarry was not consistent with the Tennessee Water Quality Act, several remediation steps were implemented between 1986 and 1994 for McCoy Branch to address disposal problems. The required ecological risk assessments of McCoy Branch watershed included provisions for biological monitoring of the watershed. The objectives of the biological monitoring were to (1) document changes in biological quality of McCoy Branch after completion of a pipeline bypassing upper McCoy Branch and further, after termination of all discharges to Rogers Quarry, (2) provide guidance on the need for additional remediation, and (3) evaluate the effectiveness of implemented remedial actions. The data from the biological monitoring program may also determine whether the goals of protection of human health and the environment of McCoy Branch are being accomplished.

  5. Open top culverts as an alternative drainage system to minimize ecological effects in earth roads.

    NASA Astrophysics Data System (ADS)

    García, Jose L.; Elorrieta, Jose; Robredo, Jose C.; García, Ricardo; García, Fernando; Gimenez, Martin C.

    2013-04-01

    During the last fifteen years a research team from School of Forestry at the Technical University of Madrid (Spain) has developed several competitive research projects regarding forest roads and open top culverts. A first approach was established with a prototype of 7 meters length in a hydraulic channel at the laboratory determining main parameters of different open top culverts in relation to different sizes of gravels and the self washing properties relationship with different slopes up to 8 %. The curves obtained may help to properly install these drainage systems avoiding maintenance costs. In addition more targeted pilot studies were developed in different forest earth roads in center and north Spain. The construction of the stations under study was financed by the U.P.M and the R&D National Plan. The main outcomes relates the low variation of humidity in a 20 m. wide range at both sides of the open top culverts and several considerations relating the angle of installation, the spacing of such drainage systems and the benefits against rilling along the roads. Also the erosion produced downhill was established and some construction methods to avoid adverse ecological effects. The diffusion of results includes congresses and a small booklet with a great acceptance in forestry services. Also a patent (ES 2 262 437) of an advanced model has been registered.

  6. Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level

    NASA Astrophysics Data System (ADS)

    Riedel, B.; Pados, T.; Pretterebner, K.; Schiemer, L.; Steckbauer, A.; Haselmair, A.; Zuschin, M.; Stachowitsch, M.

    2013-08-01

    Coastal hypoxia and anoxia have become a global key stressor to marine ecosystems, with almost 500 dead zones recorded wordwide. By triggering cascading effects from the individual organism to the community and ecosystem-level, oxygen depletions threat marine biodiversity and can alter ecosystem structure and function. By integrating both physiological function and ecological processes, animal behaviour is ideal for assessing the stress state of benthic macrofauna to low dissolved oxygen. The initial response of organisms can serve as an early-warning signal, while the successive behavioural reactions of key species indicate hypoxia levels and help assess community degradation. Here we document the behavioural responses of a representative spectrum of benthic macrofauna in the natural setting in the Northern Adriatic Sea, Mediterranean. We experimentally induced small-scale anoxia with a benthic chamber in 24 m depth to overcome the difficulties in predicting the onset of hypoxia, which often hinders full documentation in the field. The behavioural reactions were documented with a time-lapse camera. Oxygen depletion elicited significant and repeatable changes in general (visibility, locomotion, body movement and posture, location) and species-specific reactions in virtually all organisms (302 individuals from 32 species and 2 species groups). Most atypical (stress) behaviours were associated with specific oxygen thresholds: arm-tipping in the ophiuroid Ophiothrix quinquemaculata, for example, with the onset of mild hypoxia (< 2 mL O2 L-1), the emergence of polychates on the sediment surface with moderate hypoxia (< 1 mL O2 L-1), the emergence of the infaunal sea urchin Schizaster canaliferus on the sediment with severe hypoxia (< 0.5 mL O2 L-1) and heavy body rotations in sea anemones with anoxia. Other species changed their activity patterns, i.e. circadian rhythm in the hermit crab Paguristes eremita or the bioherm-associated crab Pisidia longimana. Intra- and interspecific reactions were weakened or changed: decapods ceased defensive and territorial behaviour, and predator-prey interactions and relationships shifted. This nuanced scale of resolution is a useful tool to interpret present benthic community status (behaviour) and past mortalities (community composition, e.g. survival of tolerant species). This information on the sensitivity (onset of stress response), tolerance (mortality, survival), and characteristics (i.e. life habit, functional role) of key species also helps predict potential future changes in benthic structure and ecosystem functioning. This integrated approach can transport complex ecological processes to the public and decision-makers and help define specific monitoring, assessment and conservation plans.

  7. Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level

    NASA Astrophysics Data System (ADS)

    Riedel, B.; Pados, T.; Pretterebner, K.; Schiemer, L.; Steckbauer, A.; Haselmair, A.; Zuschin, M.; Stachowitsch, M.

    2014-03-01

    Coastal hypoxia and anoxia have become a global key stressor to marine ecosystems, with almost 500 dead zones recorded worldwide. By triggering cascading effects from the individual organism to the community- and ecosystem level, oxygen depletions threaten marine biodiversity and can alter ecosystem structure and function. By integrating both physiological function and ecological processes, animal behaviour is ideal for assessing the stress state of benthic macrofauna to low dissolved oxygen. The initial response of organisms can serve as an early warning signal, while the successive behavioural reactions of key species indicate hypoxia levels and help assess community degradation. Here we document the behavioural responses of a representative spectrum of benthic macrofauna in the natural setting in the Northern Adriatic Sea (Mediterranean). We experimentally induced small-scale anoxia with a benthic chamber in 24 m depth to overcome the difficulties in predicting the onset of hypoxia, which often hinders full documentation in the field. The behavioural reactions were documented with a time-lapse camera. Oxygen depletion elicited significant and repeatable changes in general (visibility, locomotion, body movement and posture, location) and species-specific reactions in virtually all organisms (302 individuals from 32 species and 2 species groups). Most atypical (stress) behaviours were associated with specific oxygen thresholds: arm-tipping in the ophiuroid Ophiothrix quinquemaculata, for example, with the onset of mild hypoxia (< 2 mL O2 L-1), the emergence of polychaetes on the sediment surface with moderate hypoxia (< 1 mL O2 L-1), the emergence of the infaunal sea urchin Schizaster canaliferus on the sediment with severe hypoxia (< 0.5 mL O2 L-1) and heavy body rotations in sea anemones with anoxia. Other species changed their activity patterns, for example the circadian rhythm in the hermit crab Paguristes eremita or the bioherm-associated crab Pisidia longimana. Intra- and interspecific reactions were weakened or changed: decapods ceased defensive and territorial behaviour, and predator-prey interactions and relationships shifted. This nuanced scale of resolution is a useful tool to interpret present benthic community status (behaviour) and past mortalities (community composition, e.g. survival of tolerant species). This information on the sensitivity (onset of stress response), tolerance (mortality, survival), and characteristics (i.e. life habit, functional role) of key species also helps predict potential future changes in benthic structure and ecosystem functioning. This integrated approach can transport complex ecological processes to the public and decision-makers and help define specific monitoring, assessment and conservation plans.

  8. Effects of pyrite sludge pollution on soil enzyme activities: ecological dose-response model.

    PubMed

    Hinojosa, M Belén; Carreira, José A; Rodríguez-Maroto, José M; García-Ruíz, Roberto

    2008-06-25

    A laboratory study was conducted to evaluate the response of soil enzyme activities (acid and alkaline phosphatase, beta-glucosidase, arylsulfatase, urease and dehydrogenase) to different levels of trace elements pollution in soils representative of the area affected by the pyrite sludge mining spill of Aznalcóllar (Guadiamar basin, SW Spain). Three uncontaminated soils from the study area were mixed with different loads of pyrite sludge to resemble field conditions and criteria applied for reclamation practices following the pollution incident: 0% ("reference" or background level), 1.3% ("attention level", further monitoring required), 4% ("intervention level", further cleaning and liming required) and 13% (ten times the "attention level"). Enzyme activities were analysed 4, 7, 14, 21, 34 and 92 days after pollutant addition and those measured after 92 days were used to calculate the ecological dose value (ED50). Soil enzyme activities and pH decreased after the pyrite sludge addition with respect to the "reference level" (0% pyrite sludge), whereas soil bioavailable (DTPA-extractable) trace elements concentration increased. Arylsulfatase, beta-glucosidase and phosphatase activities were reduced by more than 50% at 1.3% pyrite sludge dose. Arylsulfasate was the most sensitive soil enzyme (in average, ED50=0.99), whereas urease activity showed the lowest inhibition (in average, ED50=7.87) after pyrite sludge addition. Our results showed that the ecological dose concept, applied to enzyme activities, was satisfactory to quantify the effect of a multi-metalic pollutant (pyrite sludge) on soil functionality, and would provide manageable data to establish permissible limits of trace elements in polluted soils. Additionally, we evaluate the recovery of enzyme activities after addition of sugar-beet lime (calcium carbonate) to each experimentally polluted soil. The amount of lime added to each soil was enough to raise the pH to the original value (equal to control soil), resembling field remediation practices. After lime amendment, soil recovery was still incomplete in terms of bioavailable trace elements. However, the recovery of soil enzyme activities varied widely, ranging from 0 to 100% depending on soil type and the specific enzyme. PMID:18395245

  9. Marine reserves: fish life history and ecological traits matter.

    PubMed

    Claudet, J; Osenberg, C W; Domenici, P; Badalamenti, F; Milazzo, M; Falcón, J M; Bertocci, I; Benedetti-Cecchi, L; García-Charton, J A; Goñi, R; Borg, J A; Forcada, A; De Lucia, G A; Perez-Ruzafa, A; Afonso, P; Brito, A; Guala, I; Le Diréach, L; Sanchez-Jerez, P; Somerfield, P J; Planes, S

    2010-04-01

    Marine reserves are assumed to protect a wide range of species from deleterious effects stemming from exploitation. However, some species, due to their ecological characteristics, may not respond positively to protection. Very little is known about the effects of life history and ecological traits (e.g., mobility, growth, and habitat) on responses of fish species to marine reserves. Using 40 data sets from 12 European marine reserves, we show that there is significant variation in the response of different species of fish to protection and that this heterogeneity can be explained, in part, by differences in their traits. Densities of targeted size-classes of commercial species were greater in protected than unprotected areas. This effect of protection increased as the maximum body size of the targeted species increased, and it was greater for species that were not obligate schoolers. However, contrary to previous theoretical findings, even mobile species with wide home ranges benefited from protection: the effect of protection was at least as strong for mobile species as it was for sedentary ones. Noncommercial bycatch and unexploited species rarely responded to protection, and when they did (in the case of unexploited bentho-pelagic species), they exhibited the opposite response: their densities were lower inside reserves. The use of marine reserves for marine conservation and fisheries management implies that they should ensure protection for a wide range of species with different life-history and ecological traits. Our results suggest this is not the case, and instead that effects vary with economic value, body size, habitat, depth range, and schooling behavior. PMID:20437967

  10. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    Microsoft Academic Search

    D. A. Cataldo; M. W. Ligotke; H. Jr. Bolton; R. J. Fellows; P. Van Voris; B. D. McVeety; Shu-mei W. Li; K. M. McFadden

    2009-01-01

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of

  11. Social Support and Social-ecological Resources as Mediators of Lifestyle Intervention Effects for Type 2 Diabetes

    Microsoft Academic Search

    Manuel Barrera; Deborah J. Toobert; Karyn L. Angell; Russell E. Glasgow; David P. Mackinnon

    2006-01-01

    A study was conducted to determine if an intervention could change social support and social-ecological resources of post-menopausal women diagnosed with type 2 diabetes, and if those changes mediated the intervention’s effects on health behaviors and outcomes. Women (N = 279) were randomly assigned to receive a comprehensive 6-month Mediterranean Lifestyle Program (MLP) or usual care from their physicians (UC).

  12. Ecological energetics of the desert tortoise (Gopherus Agassizii): Effects of rainfall and drought

    SciTech Connect

    Peterson, C.C. [Univ. of California, Los Angeles, CA (United States)

    1996-09-01

    To elucidate ecological effects of variation in the temporal distribution of a limiting resource (water in the Mojave Desert), energetics of two free-living populations of desert tortoises (Gopherus [=Xerobates] agassizii) were studied concurrently over 18 mo with use of doubly-labeled water. Field metabolic rates (FMR) and feeding rates were highly variable. This variability was manifested at several levels, including seasonal changes within populations, year-to-year differences within populations, and differences between populations. Underlying observed patterns and contrasts was considerable variation among individuals. Much of the variation in energetic variables was associated with a single climatic variable, rainfall. Seasonal, annual, and interpopulation differences in FMR and foraging rates corresponded to differences in availability of free-standing water from rainstorms. Some differences among individuals were apparently due to differences in proclivity or ability to drink. Tortoises had very low FMRs relative to other reptiles, allowed them to tolerate long periods of chronic energy shortage during a drought. Calculations suggested that tortoises experienced a net loss of energy shortage during a drought and tortoises experienced a net loss of energy on their spring diet of succulent annual plants. If so, tortoises require drier forage to accrue an energy profit, emphasizing reliance on drinking rainwater. Further, it suggests that growth (as protein deposition) and net acquisition of energy may be temporally decoupled in desert tortoises, with potential consequences for geographic variation in life history. Energy acquisition and expenditure in desert tortoises are strongly constrained by the contingencies of rainfall, both indirectly through effects on availability and quality of food, and directly through reliance on free-standing water for drinking, which is apparently necessary for achieving a net annual energy profit. 61 refs., 5 figs., 5 tabs.

  13. Political ecology and ecological resilience

    Microsoft Academic Search

    Garry Peterson

    2000-01-01

    The biosphere is increasingly dominated by human action. Consequently, ecology must incorporate human behavior. Political ecology, as long as it includes ecology, is a powerful framework for integrating natural and social dynamics. In this paper I present a resilience-oriented approach to political ecology that integrates system dynamics, scale, and cross-scale interactions in both human and natural systems. This approach suggests

  14. A novel deleterious PTEN mutation in a patient with early-onset bilateral breast cancer

    PubMed Central

    2014-01-01

    Background An early age at Breast Cancer (BC) onset may be a hallmark of inherited predisposition, but BRCA1/2 mutations are only found in a minority of younger BC patients. Among the others, a fraction may carry mutations in rarer BC genes, such as TP53, STK11, CDH1 and PTEN. As the identification of women harboring such mutations allows for targeted risk-management, the knowledge of associated manifestations and an accurate clinical and family history evaluation are warranted. Case presentation We describe the case of a woman who developed an infiltrating ductal carcinoma of the right breast at the age of 32, a contralateral BC at age 36 and another BC of the right breast at 40. When she was 39 years-old, during a dermatological examination, mucocutaneous features suggestive of Cowden Syndrome, a disorder associated to germ-line PTEN mutations, were noticed. PTEN genetic testing revealed the novel c.71A > T (p.Asp24Val) mutation, whose deleterious effect, suggested by conservation data and in silico tools, was definitely demonstrated by the incapacity of mutant PTEN to inhibit Akt phosphorylation when used to complement PTEN-null cells. In BC tissue, despite the absence of LOH or somatic mutations of PTEN, Akt phosphorylation was markedly increased in comparison to normal tissue, thus implying additional somatic events into the deregulation of the PI3K/Akt/mTOR pathway and, presumably, into carcinogenesis. Hence, known oncogenic mutations in PIK3CA (exons 10 and 21) and AKT1 (exon 2) were screened in tumor DNA with negative results, which suggests that the responsible somatic event(s) is a different, uncommon one. Conclusion This case stresses the importance of clinical/genetic assessment of early-onset BC patients in order to identify mutation carriers, who are at high risk of new events, so requiring tailored management. Moreover, it revealed a novel PTEN mutation with pathogenic effect, pointing out, however, the need for further efforts to elucidate the molecular steps of PTEN-associated carcinogenesis. PMID:24498881

  15. Incorporating ecologically relevant measures of pesticide effect for estimating the compatibility of pesticides and biocontrol agents.

    PubMed

    Stark, John D; Vargas, Roger; Banks, John E

    2007-08-01

    The compatibility of biological control agents with pesticides is a central concern in integrated pest management programs. The most common assessments of compatibility consist of simple comparisons of acute toxicity among pest species and select biocontrol agents. A more sophisticated approach, developed by the International Organisation of Biological Control (IOBC), is based on a tiered hierarchy made up of threshold values for mortality and sublethal effects that is used to determine the compatibility of pesticides and biological control agents. However, this method is unable to capture longer term population dynamics, which is often critical to the success of biological control and pest suppression. In this article, we used the delay in population growth index, a measure of population recovery, to investigate the potential impacts that the threshold values for levels of lethal and sublethal effects developed by the IOBC had on three biocontrol agents: sevenspotted lady beetle, Coccinella septempunctata L.; the aphid parasitoid Diaeretiella rapae (M'Intosh), and Fopius arisanus (Sonan), a parasitoid of tephritid flies. Based on life histories of these economically important natural enemies, we established a delay of 1-generation time interval as sufficient to disrupt biological control success. We found that delays equivalent to 1-generation time interval were caused by mortality as low as 50% or reductions of offspring as low as 58%, both values in line with thresholds developed by the IOBC. However, combinations of mortality and reduction of offspring lower than these values (from 32 to 43% each) over a simulated 4-mo period caused significant population delays. Furthermore, the species used in these simulations reacted differently to the same levels of effect. The parasitoid D. rapae was the most susceptible species, followed by F. arisanus and C. septempunctata. Our results indicate that it is not possible to generalize about potential long-term impacts of pesticides on biocontrol agents because susceptibility is influenced by differences in life history variables. Additionally, populations of biocontrol agents may undergo significant damage when mortality approaches 50% or when there is mortality of -30% and a 30% reduction in offspring caused by a sublethal effect. Our results suggest that more ecologically relevant measures of effect such as delays in population growth may advance our knowledge of pesticide impacts on populations of beneficial species. PMID:17849847

  16. The road to rack and ruin: selecting deleterious mitochondrial DNA variants.

    PubMed

    Holt, Ian J; Speijer, Dave; Kirkwood, Thomas B L

    2014-07-01

    Mitochondria constitute the major energy-producing compartment of the eukaryotic cell. These organelles contain many molecules of DNA that contribute only a handful of proteins required for energy production. Mutations in the DNA of mitochondria were identified as a cause of human disease a quarter of a century ago, and they have subsequently been implicated in ageing. The process whereby deleterious variants come to dominate a cell, tissue or human is the subject of debate. It is likely to involve multiple, often competing, factors, as selection pressures on mitochondrial DNA can be both indirect and intermittent, and are subjected to rapid change. Here, we assess the different models and the prospects for preventing the accumulation of deleterious mitochondrial DNA variants with time. PMID:24864317

  17. Exome Sequencing of Only Seven Qataris Identifies Potentially Deleterious Variants in the Qatari Population

    PubMed Central

    Rodriguez-Flores, Juan L.; Fuller, Jennifer; Hackett, Neil R.; Salit, Jacqueline; Malek, Joel A.; Al-Dous, Eman; Chouchane, Lotfi; Zirie, Mahmoud; Jayoussi, Amin; Mahmoud, Mai A.; Crystal, Ronald G.; Mezey, Jason G.

    2012-01-01

    The Qatari population, located at the Arabian migration crossroads of African and Eurasia, is comprised of Bedouin, Persian and African genetic subgroups. By deep exome sequencing of only 7 Qataris, including individuals in each subgroup, we identified 2,750 nonsynonymous SNPs predicted to be deleterious, many of which are linked to human health, or are in genes linked to human health. Many of these SNPs were at significantly elevated deleterious allele frequency in Qataris compared to other populations worldwide. Despite the small sample size, SNP allele frequency was highly correlated with a larger Qatari sample. Together, the data demonstrate that exome sequencing of only a small number of individuals can reveal genetic variations with potential health consequences in understudied populations. PMID:23139751

  18. Prediction of deleterious non-synonymous SNPs based on protein interaction network and hybrid properties.

    PubMed

    Huang, Tao; Wang, Ping; Ye, Zhi-Qiang; Xu, Heng; He, Zhisong; Feng, Kai-Yan; Hu, Lele; Cui, Weiren; Wang, Kai; Dong, Xiao; Xie, Lu; Kong, Xiangyin; Cai, Yu-Dong; Li, Yixue

    2010-01-01

    Non-synonymous SNPs (nsSNPs), also known as Single Amino acid Polymorphisms (SAPs) account for the majority of human inherited diseases. It is important to distinguish the deleterious SAPs from neutral ones. Most traditional computational methods to classify SAPs are based on sequential or structural features. However, these features cannot fully explain the association between a SAP and the observed pathophysiological phenotype. We believe the better rationale for deleterious SAP prediction should be: If a SAP lies in the protein with important functions and it can change the protein sequence and structure severely, it is more likely related to disease. So we established a method to predict deleterious SAPs based on both protein interaction network and traditional hybrid properties. Each SAP is represented by 472 features that include sequential features, structural features and network features. Maximum Relevance Minimum Redundancy (mRMR) method and Incremental Feature Selection (IFS) were applied to obtain the optimal feature set and the prediction model was Nearest Neighbor Algorithm (NNA). In jackknife cross-validation, 83.27% of SAPs were correctly predicted when the optimized 263 features were used. The optimized predictor with 263 features was also tested in an independent dataset and the accuracy was still 80.00%. In contrast, SIFT, a widely used predictor of deleterious SAPs based on sequential features, has a prediction accuracy of 71.05% on the same dataset. In our study, network features were found to be most important for accurate prediction and can significantly improve the prediction performance. Our results suggest that the protein interaction context could provide important clues to help better illustrate SAP's functional association. This research will facilitate the post genome-wide association studies. PMID:20689580

  19. Prediction of Deleterious Non-Synonymous SNPs Based on Protein Interaction Network and Hybrid Properties

    PubMed Central

    Xu, Heng; He, Zhisong; Feng, Kai-Yan; Hu, LeLe; Cui, WeiRen; Wang, Kai; Dong, Xiao; Xie, Lu; Kong, Xiangyin; Cai, Yu-Dong; Li, Yixue

    2010-01-01

    Non-synonymous SNPs (nsSNPs), also known as Single Amino acid Polymorphisms (SAPs) account for the majority of human inherited diseases. It is important to distinguish the deleterious SAPs from neutral ones. Most traditional computational methods to classify SAPs are based on sequential or structural features. However, these features cannot fully explain the association between a SAP and the observed pathophysiological phenotype. We believe the better rationale for deleterious SAP prediction should be: If a SAP lies in the protein with important functions and it can change the protein sequence and structure severely, it is more likely related to disease. So we established a method to predict deleterious SAPs based on both protein interaction network and traditional hybrid properties. Each SAP is represented by 472 features that include sequential features, structural features and network features. Maximum Relevance Minimum Redundancy (mRMR) method and Incremental Feature Selection (IFS) were applied to obtain the optimal feature set and the prediction model was Nearest Neighbor Algorithm (NNA). In jackknife cross-validation, 83.27% of SAPs were correctly predicted when the optimized 263 features were used. The optimized predictor with 263 features was also tested in an independent dataset and the accuracy was still 80.00%. In contrast, SIFT, a widely used predictor of deleterious SAPs based on sequential features, has a prediction accuracy of 71.05% on the same dataset. In our study, network features were found to be most important for accurate prediction and can significantly improve the prediction performance. Our results suggest that the protein interaction context could provide important clues to help better illustrate SAP's functional association. This research will facilitate the post genome-wide association studies. PMID:20689580

  20. Comparison and integration of deleteriousness prediction methods for nonsynonymous SNVs in whole exome sequencing studies.

    PubMed

    Dong, Chengliang; Wei, Peng; Jian, Xueqiu; Gibbs, Richard; Boerwinkle, Eric; Wang, Kai; Liu, Xiaoming

    2015-04-15

    Accurate deleteriousness prediction for nonsynonymous variants is crucial for distinguishing pathogenic mutations from background polymorphisms in whole exome sequencing (WES) studies. Although many deleteriousness prediction methods have been developed, their prediction results are sometimes inconsistent with each other and their relative merits are still unclear in practical applications. To address these issues, we comprehensively evaluated the predictive performance of 18 current deleteriousness-scoring methods, including 11 function prediction scores (PolyPhen-2, SIFT, MutationTaster, Mutation Assessor, FATHMM, LRT, PANTHER, PhD-SNP, SNAP, SNPs&GO and MutPred), 3 conservation scores (GERP++, SiPhy and PhyloP) and 4 ensemble scores (CADD, PON-P, KGGSeq and CONDEL). We found that FATHMM and KGGSeq had the highest discriminative power among independent scores and ensemble scores, respectively. Moreover, to ensure unbiased performance evaluation of these prediction scores, we manually collected three distinct testing datasets, on which no current prediction scores were tuned. In addition, we developed two new ensemble scores that integrate nine independent scores and allele frequency. Our scores achieved the highest discriminative power compared with all the deleteriousness prediction scores tested and showed low false-positive prediction rate for benign yet rare nonsynonymous variants, which demonstrated the value of combining information from multiple orthologous approaches. Finally, to facilitate variant prioritization in WES studies, we have pre-computed our ensemble scores for 87 347 044 possible variants in the whole-exome and made them publicly available through the ANNOVAR software and the dbNSFP database. PMID:25552646

  1. Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a polder habitat

    PubMed Central

    Lessel, Tanja; Marx, Michael Thomas; Eisenbeis, Gerhard

    2011-01-01

    Abstract Within the scope of the Integrated Rhine Program an ecological flood gate and channel was inserted into the polder “Ingelheim” to enhance animal and plant diversity. In 2008, carabid beetles and springtails were collected, using pitfall traps, to measure the effects of ecological flooding and a strong precipitation event at a flood-disturbed and a dry location in this area. At both localities, xerophilic and mesophilic carabid beetle species were dominant throughout the study period. The total number of individuals of hygrophilic species was comparatively constant, while species number increased, partly due to the changed moisture conditions caused by ecological flooding and strong precipitation. Carabid beetle diversity and evenness decreased marginally when ecological flooding was absent. Springtails represent a less mobile arthropod order, and as such the impact of ecological flooding was stronger. An increase in both numbers of species and individuals of hygrophilic and hygrotolerant species occurred in the flood-disturbed location after ecological flooding. After the sites at both locations had dried, the number of individuals belonging to these species declined rapidly. In contrast to carabid species, the strong precipitation event showed no influence on hygrophilic springtail species. Thus, collembolan diversity and evenness decreased markedly in the absence of flooding. We showed that ecological flooding has an influence on the spatial and temporal dynamics of different arthropod groups that inhabit the polder “Ingelheim”. These findings demonstrate the importance of using different arthropod groups as bioindicators in determining the ecological value of a particular polder design. PMID:21738425

  2. DESIGNING PESTICIDE METABOLIC PATHWAY/DEGRADATE DATABASES FOR REGISTRANT SUBMITTED HEALTH EFFECTS/ECOLOGICAL EFFECTS DATA

    EPA Science Inventory

    OPPTS requires information on the toxic effects of pesticide metabolites as well as the parent chemical. Currently, OPP receives metabolic maps with registrant study data submissions, but there is no efficient way to access previously submitted maps on similar chemicals to help w...

  3. The evolution of XY recombination: sexually antagonistic selection versus deleterious mutation load.

    PubMed

    Grossen, Christine; Neuenschwander, Samuel; Perrin, Nicolas

    2012-10-01

    Recombination arrest between X and Y chromosomes, driven by sexually antagonistic genes, is expected to induce their progressive differentiation. However, in contrast to birds and mammals (which display the predicted pattern), most cold-blooded vertebrates have homomorphic sex chromosomes. Two main hypotheses have been proposed to account for this, namely high turnover rates of sex-determining systems and occasional XY recombination. Using individual-based simulations, we formalize the evolution of XY recombination (here mediated by sex reversal; the "fountain-of-youth" model) under the contrasting forces of sexually antagonistic selection and deleterious mutations. The shift between the domains of elimination and accumulation occurs at much lower selection coefficients for the Y than for the X. In the absence of dosage compensation, mildly deleterious mutations accumulating on the Y depress male fitness, thereby providing incentives for XY recombination. Under our settings, this occurs via "demasculinization" of the Y, allowing recombination in XY (sex-reversed) females. As we also show, this generates a conflict with the X, which coevolves to oppose sex reversal. The resulting rare events of XY sex reversal are enough to purge the Y from its load of deleterious mutations. Our results support the "fountain of youth" as a plausible mechanism to account for the maintenance of sex-chromosome homomorphy. PMID:23025605

  4. Somatic deleterious mutation rate in a woody plant: estimation from phenotypic data

    PubMed Central

    Bobiwash, K; Schultz, S T; Schoen, D J

    2013-01-01

    We conducted controlled crosses in populations of the long-lived clonal shrub, Vaccinium angustifolium (lowbush blueberry) to estimate inbreeding depression and mutation parameters associated with somatic deleterious mutation. Inbreeding depression level was high, with many plants failing to set fruit after self-pollination. We also compared fruit set from autogamous pollinations (pollen collected from within the same inflorescence) with fruit set from geitonogamous pollinations (pollen collected from the same plant but from inflorescences separated by several meters of branch growth). The difference between geitonogamous versus autogamous fitness within single plants is referred to as ‘autogamy depression' (AD). AD can be caused by somatic deleterious mutation. AD was significantly different from zero for fruit set. We developed a maximum-likelihood procedure to estimate somatic mutation parameters from AD, and applied it to geitonogamous and autogamous fruit set data from this experiment. We infer that, on average, approximately three sublethal, partially dominant somatic mutations exist within the crowns of the plants studied. We conclude that somatic mutation in this woody plant results in an overall genomic deleterious mutation rate that exceeds the rate measured to date for annual plants. Some implications of this result for evolutionary biology and agriculture are discussed. PMID:23778990

  5. Deleterious mutations and the genetic variance of male fitness components in Mimulus guttatus.

    PubMed Central

    Kelly, John K

    2003-01-01

    Deleterious mutations are relevant to a broad range of questions in genetics and evolutionary biology. I present an application of the "biometric method" for estimating mutational parameters for male fitness characters of the yellow monkeyflower, Mimulus guttatus. The biometric method rests on two critical assumptions. The first is that experimental inbreeding changes genotype frequencies without changing allele frequencies; i.e., there is no genetic purging during the experiment. I satisfy this condition by employing a breeding design in which the parents are randomly extracted, fully homozygous inbred lines. The second is that all genetic variation is attributable to deleterious mutations maintained in mutation-selection balance. I explicitly test this hypothesis using likelihood ratios. Of the three deleterious mutation models tested, the first two are rejected for all characters. The failure of these models is due to an excess of additive genetic variation relative to the expectation under mutation-selection balance. The third model is not rejected for either of two log-transformed male fitness traits. However, this model imposes only "weak conditions" and is not sufficiently detailed to provide estimates for mutational parameters. The implication is that, if biometric methods are going to yield useful parameter estimates, they will need to consider mutational models more complicated than those typically employed in experimental studies. PMID:12871916

  6. The ecological effects of thermopeaking in Alpine streams in flume simulations

    NASA Astrophysics Data System (ADS)

    Maiolini, Bruno; Carolli, Mauro; Bruno, M. Cristina; Siviglia, Annunziato

    2010-05-01

    In Alpine areas, the temporal patterns of hydropower plants operations can have consequences for the water bodies which receive downstream releases in the form of "hydropeaking", typically consisting in sharp releases of turbinated water in the river reaches below dams. Hydropeaking may significantly affect also the thermal regime of rivers: typically power plants fed by hypolimnetic releases from large dams cause a reduction in summer temperature and an increase in winter temperatures for long distances downstream. Very few studies have addressed the effects of the short-term temperature fluctuations related to hydropeaking (i.e., thermopeaking) on aquatic fauna, although they can be a major cause of riverine habitat degradation posing serious threats to aquatic communities. In the Adige River watershed, warm thermopeaking occurs from September to January and results in additional (up to 4°C) heating to the natural dial fluctuations; cold thermopeaking occurs from March to July and cools down the temperature (up to 6°C), in contrast with the natural trend that would result in heating during the day. The biological effects of thermopeaking are difficult to study in nature, because they are associated with hydropeaking, which is known to cause a high catastrophic drift due to the increased intensity of bed scour. However, controlled simulations of thermopeaking events could be performed in artificial flumes. We used artificial flumes which had proved to perform discharge manipulations which simulate hydropeaking events, and conducted four simulations, two warm thermopeakings in early and late winter, and two cold-thermopeakings, in early and late summer, respectively. The impact of thermopeaking on benthic macroinvertebrates was assessed by collecting those organisms which are displaced from the substrate and drift in the water column. Displacement can be active (i.e., part of the behavioural repertoire of certain insect species), or passive (i.e., catastrophic and generated by any disturbance). Drifting invertebrates were collected at time intervals before the simulation, and at continuous, short-time intervals during the simulation in order to follow the changes in drift over a short time period during the simulation. We assessed the effects of thermopreaking on the benthos community by answering to the following questions: 1) Do thermal alterations induce an increase in drift of benthic invertebrates? 3) Do a reduction or an increase in water temperature have different effects of invertebrate drift? Benthic invertebrates responded more to the cold thermopeaking simulations, with differences among taxa with different life strategies and ecological requirements.

  7. Historical ecology: using unconventional data sources to test for effects of global environmental change.

    PubMed

    Vellend, Mark; Brown, Carissa D; Kharouba, Heather M; McCune, Jenny L; Myers-Smith, Isla H

    2013-07-01

    Predicting the future ecological impact of global change drivers requires understanding how these same drivers have acted in the past to produce the plant populations and communities we see today. Historical ecological data sources have made contributions of central importance to global change biology, but remain outside the toolkit of most ecologists. Here we review the strengths and weaknesses of four unconventional sources of historical ecological data: land survey records, "legacy" vegetation data, historical maps and photographs, and herbarium specimens. We discuss recent contributions made using these data sources to understanding the impacts of habitat disturbance and climate change on plant populations and communities, and the duration of extinction-colonization time lags in response to landscape change. Historical data frequently support inferences made using conventional ecological studies (e.g., increases in warm-adapted species as temperature rises), but there are cases when the addition of different data sources leads to different conclusions (e.g., temporal vegetation change not as predicted by chronosequence studies). The explicit combination of historical and contemporary data sources is an especially powerful approach for unraveling long-term consequences of multiple drivers of global change. Despite the limitations of historical data, which include spotty and potentially biased spatial and temporal coverage, they often represent the only means of characterizing ecological phenomena in the past and have proven indispensable for characterizing the nature, magnitude, and generality of global change impacts on plant populations and communities. PMID:23804553

  8. Eco-genetic model to explore fishing-induced ecological and evolutionary effects on growth and maturation schedules

    PubMed Central

    Wang, Hui-Yu; Höök, Tomas O

    2009-01-01

    Eco-genetic individual-based models involve tracking the ecological dynamics of simulated individual organisms that are in part characterized by heritable parameters. We developed an eco-genetic individual-based model to explore ecological and evolutionary interactions of fish growth and maturation schedules. Our model is flexible and allows for exploration of the effects of heritable growth rates (based on von Bertalanffy and biphasic growth patterns), heritable maturation schedules (based on maturation reaction norm concepts), or both on individual- and population-level traits. In baseline simulations with rather simple ecological trade-offs and over a relatively short time period (<200 simulation years), simulated male and female fish evolve differential genetic growth and maturation. Further, resulting patterns of genetically determined growth and maturation are influenced by mortality rate and density-dependent processes, and maturation and growth parameters interact to mediate the evolution of one another. Subsequent to baseline simulations, we conducted experimental simulations to mimic fisheries harvest with two size-limits (targeting large or small fish), an array of fishing mortality rates, and assuming a deterministic or stochastic environment. Our results suggest that fishing with either size-limit may induce considerable changes in life-history trait expression (maturation schedules and growth rates), recruitment, and population abundance and structure. However, targeting large fish would cause more adverse genetic effects and may lead to a population less resilient to environmental stochasticity. PMID:25567890

  9. [Effect of temperature on proteinase activities of enteral microbiota and intestinal mucosa of fish of different ecological group].

    PubMed

    Kuz'mina, V V; Shalygin, M V; Skvortsova, E G

    2012-01-01

    Effect of temperature on proteinases activities of enteral microbiota and of intestinal mucosa was studied in five fish species (roach Rutilus rutilus, crucian carp Carassius carassius, common perch Perca fluviatilis, pike-perch Zander lucioperca, and pike Esox lucius) belonging by the nutrition type to different ecological groups. Essential differences of temperature characteristics of proteinases of intestinal mucosa and of enteral microbiota are revealed in fish belonging by the nutrition type to different ecologic groups. The character of the t0-function of proteinases of intestinal mucosa and enteral microbiota by casein and hemoglobin as a rule is different. The highest values of relative proteinases activities for casein in the zone of low temperatures (38 and 45.3 % of the maximal activity) are found at study of proteinases of enteral microbiota in common perch and crucian carp. The latter indicates a significant adaptability of the enteral microbiota proteinases of common perch and crucial carp to functioning at low temperatures. PMID:22645973

  10. Journal of Animal Ecology 2007

    E-print Network

    Steve Kemp

    ­mark­recapture, conservation, genetic drift, migration, Ne. Journal of Animal Ecology (2007) 76, 790­800 doi: 10.1111/j.1365Journal of Animal Ecology 2007 76, 790­800 © 2007 The Authors. Journal compilation © 2007 British Ecological Society Blackwell Publishing Ltd Effective population sizes and migration rates in fragmented

  11. Community metabolism of aquatic Closed Ecological Systems: Effects of nitrogen sources

    NASA Astrophysics Data System (ADS)

    Taub, Frieda B.

    2009-10-01

    To investigate the effect of nitrogen sources on Closed Ecological Systems (CESs), three nitrogen sources (NaNO 3, sodium nitrate; NH 4Cl, ammonium chloride; and NH 4NO 3, ammonium nitrate) were each tested in freshwater CESs consisting of a chemically defined medium, three species of green algae ( Ankistrodesmus, S cenedesmus, and Selenastrum), the grazer Daphnia magna, and associated microbes, under 12 h light/12 h dark cycles. It had been hypothesized that the development of high pH in earlier CESs was the result of nitrate utilization, and that ammonium might result in acid conditions, while ammonium nitrate might result in more moderate pH. The three nitrogen sources supported similar densities of algae (estimated by in vivo fluorescence) and similar Daphnia populations. The experiments showed that pH levels rapidly increased when grazers were absent or at low abundances irrespective of the nitrogen source. Consequently, it is hypothesized that carbon cycles, rather than nitrogen sources, are responsible for the pH dynamics. Oxygen diurnal (light:dark) cycles tended to come into balance more quickly than pH. It may be more feasible to convert O 2 data to energy units (using "oxycalorific" values) than CO 2 data since CO 2 dynamics may include other chemical reactions than just photosynthesis and respiration. The feasibility of sustaining grazer populations for at least several weeks in small, simple CESs was demonstrated, along with the ability to monitor algae-grazer dynamics, and the recording of O 2 and pH measurements.

  12. Fate and ecological effects of decabromodiphenyl ether in a field lysimeter.

    PubMed

    Du, Wenchao; Ji, Rong; Sun, Yuanyuan; Zhu, Jianguo; Wu, Jichun; Guo, Hongyan

    2013-08-20

    Flame-retardant polybrominated diphenyl ethers (PBDEs) are environmental contaminants. Deca-BDE is increasingly used commercially, but little is known about the long-term fate and impact of its major component, decabromodiphenyl ether (BDE-209), on the soil environment. In this study, we investigated the fate and ecological effect of BDE-209 over 4 years in outdoor lysimeters in a field planted with a rice-wheat rotation. BDE-209 and six lower-brominated PBDEs (BDE-28, -47, -99, -153, -154, and -183) were detected in soil layers of the test lysimeter. We calculated an average BDE-209 migration rate of 1.54 mg·m(-2)·yr(-1). In samples collected in May 2008, November 2008, November 2009, November 2010, and November 2011, 95.5%, 94.3%, 108.1%, 33.8%, and 35.5% of the spiked BDE-209 were recovered, respectively. We predicted the major pathway for debromination of BDE-209 in soil to be: BDE-209?BDE-183?BDE-153/BDE-154?BDE-99?BDE-47?BDE-28. In plants, BDE-209 and seven lower-brominated PBDEs (BDE-28, -47, -99, -100, -153, -154, and -183) were detected. BDE-100 was mainly derived from the debromination of BDE-154 in plants, but sources of other lower-brominated PBDEs were still difficult to determine. In soils containing BDE-209 for 4 years, soil urease activity increased, and soil protease activity slightly decreased. Our results provide important insights for understanding the behavior of BDE-209 in agricultural soils. PMID:23899302

  13. Infectious disease ecology: Effects of ecosystems on disease and of disease on ecosystems: A Review

    E-print Network

    Peterson, A. Townsend

    2009-11-01

    to grow and reproduce. This is also a positive feedback process. It is the essence of life. But ecology (as I know it) is about something different. It deals with the world within which an organism exists, which determines how much space and food... regulates its numbers. It is the sub- stance of ecology. Strangely, Ulanowicz seems little concerned with this process. He is interested, mainly, in the flow of energy. Like most other ecologists, however, I am not really concerned with the energetics...

  14. Effects of Changes in Lugu Lake Water Quality on Schizothorax Yunnansis Ecological Habitat Based on HABITAT Model

    NASA Astrophysics Data System (ADS)

    Huang, Wei; Mynnet, Arthur

    Schizothorax Yunnansis is an unique fish species only existing in Lugu Lake, which is located in the southwestern China. The simulation and research on Schizothorax Yunnansis habitat environment have a vital significance to protect this rare fish. With the development of the tourism industry, there bring more pressure on the environmental protection. The living environment of Schizothorax Yunnansis is destroyed seriously because the water quality is suffering the sustaining pollution of domestic sewage from the peripheral villages. This paper analyzes the relationship between water quality change and Schizothorax Yunnansis ecological habitat and evalutes Schizothorax Yunnansis's ecological habitat impact based on HABITAT model. The results show that when the TP concentration in Lugu Lake does not exceed Schizothorax Yunnansis's survival threshold, Schizothorax Yunnansis can get more nutrients and the suitable habitat area for itself is increased. Conversely, it can lead to TP toxicity in the Schizothorax Yunnansis and even death. Therefore, unsuitable habitat area for Schizothorax Yunnansis is increased. It can be seen from the results that HABITAT model can assist in ecological impact assessment studies by translating results of hydrological, water quality models into effects on the natural environment and human society.

  15. Cellular and Behavioral Effects of Stilbene Resveratrol Analogs: Implications for Reducing the Deleterious Effects of Aging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is a plethora of research that suggests that polyphenolic compounds contained in fruits and vegetables that are rich in color may have potent antioxidant and anti-inflammatory activities. In several previous studies, we found that crude blueberry (BB) extract significantly attenuated age-relat...

  16. Effects of ecological factors and human activities on nonpoint source pollution in the upper reach of the Yangtze River and its management strategies

    NASA Astrophysics Data System (ADS)

    Ding, X. W.; Shen, Z. Y.; Liu, R. M.; Chen, L.; Lin, M.

    2014-01-01

    The effects of ecological and human activities on nonpoint source (NPS) pollution are key issues for sustainable water resources management. In this study, the Improved Export Coefficient Model and the Revised Universal Soil Loss Equation were adopted to estimate the annual loads of NPS pollutants during the period from 1960 through 2003 in the upper reach of the Yangtze River (URYR). Ecological factors and human activities affecting NPS pollution were distinguished and their respective effects were assessed. Variations of the dominant cause (between ecological factors and human activities) were presented. Furthermore, the combined effect of them on NPS pollution were successfully revealed. The results showed that the annual loads raised from ecological factors of dissolved nitrogen (DN) and dissolved phosphorus (DP) were relatively steady from 1960 to 2003. But those of sediment, absorbed nitrogen (AN) and absorbed phosphorus (AP) decreased during that period. In terms of the annual loads caused by human activities, those of dissolved pollutants increased from 1960 to 2000 and then fell. Those of sediment as well as absorbed pollutants peaked in 1980 and then decreased. Simultaneously, the dominant cause of DN loads shifted from ecological factors to human activities after 1980 while DP loads were mainly contributed by human activities. However, sediment, dissolved pollutants were primarily exported by ecological factors. Finally, strategies for managing anthropogenic activities were proposed and their effects on NPS pollution reduction were also depicted quantitatively.

  17. Adapting to Climate Change on Western Public Lands: Addressing the Ecological Effects of Domestic, Wild, and Feral Ungulates

    NASA Astrophysics Data System (ADS)

    Beschta, Robert L.; Donahue, Debra L.; DellaSala, Dominick A.; Rhodes, Jonathan J.; Karr, James R.; O'Brien, Mary H.; Fleischner, Thomas L.; Deacon Williams, Cindy

    2013-02-01

    Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an altered environment. Historical and contemporary livestock production—the most widespread and long-running commercial use of public lands—can alter vegetation, soils, hydrology, and wildlife species composition and abundances in ways that exacerbate the effects of climate change on these resources. Excess abundance of native ungulates (e.g., deer or elk) and feral horses and burros add to these impacts. Although many of these consequences have been studied for decades, the ongoing and impending effects of ungulates in a changing climate require new management strategies for limiting their threats to the long-term supply of ecosystem services on public lands. Removing or reducing livestock across large areas of public land would alleviate a widely recognized and long-term stressor and make these lands less susceptible to the effects of climate change. Where livestock use continues, or where significant densities of wild or feral ungulates occur, management should carefully document the ecological, social, and economic consequences (both costs and benefits) to better ensure management that minimizes ungulate impacts to plant and animal communities, soils, and water resources. Reestablishing apex predators in large, contiguous areas of public land may help mitigate any adverse ecological effects of wild ungulates.

  18. Adapting to climate change on Western public lands: addressing the ecological effects of domestic, wild, and feral ungulates.

    PubMed

    Beschta, Robert L; Donahue, Debra L; DellaSala, Dominick A; Rhodes, Jonathan J; Karr, James R; O'Brien, Mary H; Fleischner, Thomas L; Deacon Williams, Cindy

    2013-02-01

    Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an altered environment. Historical and contemporary livestock production-the most widespread and long-running commercial use of public lands-can alter vegetation, soils, hydrology, and wildlife species composition and abundances in ways that exacerbate the effects of climate change on these resources. Excess abundance of native ungulates (e.g., deer or elk) and feral horses and burros add to these impacts. Although many of these consequences have been studied for decades, the ongoing and impending effects of ungulates in a changing climate require new management strategies for limiting their threats to the long-term supply of ecosystem services on public lands. Removing or reducing livestock across large areas of public land would alleviate a widely recognized and long-term stressor and make these lands less susceptible to the effects of climate change. Where livestock use continues, or where significant densities of wild or feral ungulates occur, management should carefully document the ecological, social, and economic consequences (both costs and benefits) to better ensure management that minimizes ungulate impacts to plant and animal communities, soils, and water resources. Reestablishing apex predators in large, contiguous areas of public land may help mitigate any adverse ecological effects of wild ungulates. PMID:23151970

  19. A review of the ecological effects of river regulation in Australia

    Microsoft Academic Search

    K. F. Walker

    1985-01-01

    Responses to hydrologic change are an important theme in lotic ecology, and data for Australian rivers are accumulating in a rapid, butad hoc manner. Thia paper arranges recent contributions according to the major drainage divisions, which provide reasonably coherent environmental units. The east coastal rivers are exploited for storage, power generation and waste disposal, and Tasmanian rivers are regulated to

  20. Designing sampling protocols for evaluating ecological effects of conservation practices on agricultural streams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous evaluations of the influence of conservation practices on agricultural streams have focused on water chemistry. Ecological assessments documenting how the habitat and aquatic biota within agricultural streams respond to conservation practices are lacking despite a critical need for this inf...

  1. ECOLOGICAL ENDPOINT MODELING FOR TMDLS: EFFECTS OF SEDIMENT ON FISH POPULATIONS

    EPA Science Inventory

    Sediment is one of the primary stressors of concern for Total Maximum Daily Loads (TMDLs) for streams, and often it is a concern because of its impact on ecological endpoints. A modeling approach relating sediment to stream fish population dynamics is presented. Equations are d...

  2. Effects of ecological succession on surface mineral horizons in Japanese volcanic ash soil

    Microsoft Academic Search

    Yasuo Iimura; Mari Fujimoto; Mitsuru Hirota; Kenji Tamura; Teruo Higashi; Koyo Yonebayashi; Nobuhide Fujitake

    2010-01-01

    Japanese volcanic ash soils have very thick and dark-colored A horizons with large amounts of black humic acids which are characterized by their extremely high aromatic structure and stabilities such as black carbon. Nevertheless, the disappearance of the melanic epipedon with a decreasing aromatic C and increasing alkyl C proportion of humic acids was observed in ecological succession for only

  3. Ecological Modelling 132 (2000) 175190 Edge effects in fragmented landscapes: a generic model for

    E-print Network

    Chen, Jiquan

    for delineating area of edge influences (D-AEI) Daolan Zheng *, Jiquan Chen School of Forestry and Wood Products@geog.umd.edu (D. Zheng). 0304-3800/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S0304-3800(00)00254-4 #12;D. Zheng, J. Chen / Ecological Modelling 132 (2000) 175­190176 al., 1993

  4. MICROCOSMS AS TEST SYSTEMS FOR THE ECOLOGICAL EFFECTS OF TOXIC SUBSTANCES: AN APPRAISAL WITH CADMIUM

    EPA Science Inventory

    A two-phase set of experiments was conducted to address some of the problems inherent in ecological screening of toxic substances in aquatic microcosms. Phase I was a 4 x 4 factorial experiment (four levels of cadmium versus four levels of nutrient enrichment) on the interactive ...

  5. The stingray AUV: A small and cost-effective solution for ecological monitoring

    Microsoft Academic Search

    Christopher Barngrover; Ryan Kastner; Thomas Denewiler; Greg Mills

    2011-01-01

    Underwater vehicles have recently become more useful in ecological monitoring, largely in part to advanced processing capabilities enabled by modern computers. Most underwater vehicles are torpedo shaped and non-holonomically controlled, which makes them efficient, but they lack precise maneuverability. Some cube-shaped vehicles are used when more exact navigation is necessary; however they cannot take advantage of gliding motions and hydrodynamic

  6. Cascading effects of introduced Nile perch (Lates niloticus) on the foraging ecology of Nile tilapia

    E-print Network

    Chapman, Lauren J.

    - indigenous fish species in the Lake Victoria Basin of East Africa has been followed by dramatic ecological 2000; Pringle 2005). Although many fish stocks in Lake Victoria had declined prior to expansion followed that observed in Lake Victoria (Ogutu- Ohwayo 1993; Chapman et al. 1996a,b). Four non- indigenous

  7. Exploring the effects of local development regulations on ecological landscape structure

    E-print Network

    Kim, Jin Ki

    2005-08-29

    An ecological approach to land-use planning is essential to maintain the long-term sustainability of ecosystem benefits, services, and resources. Concern about environmental quality and the long-term livability of urban areas is now a driving force...

  8. COMMUNITY AND ECOSYSTEM ECOLOGY Effects of Natural Forest Fragmentation on a

    E-print Network

    Gillespie, Rosemary

    of human intrusion. Activities asso- ciated with human-related habitat fragmentation can attract invasive for human uses. Therefore, understanding the ecological and evolutionary impli- cations of fragmentation observations (but see Watson 2003). In addition, because most of the fragmentation under study is human induced

  9. The Three-Dimensional Ecological Planning: An Effective Approach to Control the Urban Sprawl

    Microsoft Academic Search

    Huang Leichang; Fan Zhengqiu; Wang Xiangrong; Guxun; Li Ruixuan; Cao Fucun; Ye Shuhong

    2008-01-01

    Urban sprawl caused quantities of environmental and social problems, the conflicts between the requirements of urbanization and the limited carrying capacities of resources and vulnerable environments are increasingly fierce. The sustainable development of the city has become an important topic. And ecological planning is the optimum method for the realization of this sustainability. This paper, aiming to control the urban

  10. Rainfall in arid zones: possible effects of climate change on the population ecology of blue cranes

    Microsoft Academic Search

    Res Altwegg; Mark D. Anderson

    2009-01-01

    Summary 1. Understanding the demographic mechanisms through which climate affects population dynamics is critical for predicting climate change impacts on biodiversity. In arid habitats, rainfall is the most important forcing climatic factor. Rainfall in arid zones is typically variable and unpredictable, and we therefore hypothesise that its seasonality and variability may be as important for the population ecology of arid

  11. ECOLOGICAL AND NONHUMAN BIOLOGICAL EFFECTS OF SOLAR UV-B RADIATION

    EPA Science Inventory

    Recent studies regarding the impact of UV-B radiation upon ecological and nonhuman biological systems is the subject of the report. For years scientists and laymen alike have causally noted the impact of solar ultraviolet radiation upon the non-human component of the biosphere. S...

  12. Ecological Footprint

    NSDL National Science Digital Library

    Connecticut Energy Education

    Students explore their own Ecological Footprint in the context of how many Earths it would take if everyone used the same amount of resources they did. They compare this to the Ecological Footprint of individuals in other parts of the world and to the Ecological footprint of a family member when they were the student's age.

  13. Ecological Footprint

    NSDL National Science Digital Library

    2007-01-01

    Students explore their own Ecological Footprint in the context of how many Earths it would take if everyone used the same amount of resources they did. They compare this to the Ecological Footprint of individuals in other parts of the world and to the Ecological footprint of a family member when they were the student's age.

  14. Backyard Ecology.

    ERIC Educational Resources Information Center

    Elser, Monica; Musheno, Birgit; Saltz, Charlene

    2003-01-01

    Describes the Ecology Explorers, the community education component of Arizona State University's Central Arizona Phoenix Long-Term Ecological Research project, which offers teacher internship programs that link university researchers, K-12 teachers, and students in studying urban ecology. Explains that student neighborhoods are dynamic ecosystems…

  15. Overview of the effects of the coal fuel cycle on hydrology, water quality and use, and aquatic ecology

    SciTech Connect

    Cushman, R.M.; Gough, S.B.; Moran, M.S.

    1980-05-01

    Literature is summarized for the effects of the coal fuel cycle (mining, mine-site processing, transportation, storage, onsite processing, combustion, and waste collection and disposal) on water resources. Aspects considered include surface- and ground-water hydrology, water quality and use, and aquatic ecology. Water use is discussed with regard to both availability and water quality constraints on use. Requirements of the recently enacted Surface Mining Control and Reclamation Act are introduced where appropriate. For the combustion step in the fuel cycle, only those effects which are specific to coal as a fuel are addressed. Effects not specific to coal use (such as thermal effects, impingement, and entrainment resulting from cooling water withdrawal and use) are not considered. Reference is made to more exhaustive studies of the topics reviewed. A summary of the major environmental effects of the coal fuel cycle is given below.

  16. Using Ecological Theory to Evaluate the Effectiveness of an Indigenous Community Intervention: A Study of Sexual Assault Nurse Examiner (SANE) Programs

    Microsoft Academic Search

    Rebecca Campbell; Debra Patterson; Giannina Fehler-Cabral

    2010-01-01

    In recent years, there has been renewed interest among community psychologists in indigenous interventions, which are programs\\u000a created by local practitioners (rather than researchers) already rooted in their communities. Indigenous interventions have\\u000a strong ecological validity, but their effectiveness is often unknown because so few are rigorously evaluated. The goal of\\u000a this project was to use Kelly and Trickett’s ecological theory

  17. ECOLOGICAL FORECASTING FOR WATERSHEDS

    EPA Science Inventory

    To effectively manage watersheds, the assessment of watershed ecological response to physicochemical stressors such as nutrients, sediments, pathogens, and toxics over broad spatial and temporal scales is needed. Assessments at this level of complexity requires the development of...

  18. Application of microcosmic system for assessment of insecticide effects on biomarker responses in ecologically different earthworm species.

    PubMed

    Velki, Mirna; Hackenberger, Branimir K; Lon?ari?, Zeljka; Hackenberger, Davorka K

    2014-06-01

    Earthworms from different ecological categories--epigeic Eisenia andrei and Lumbricus rubellus, endogeic Octolasion lacteum and anecic Lumbricus terrestris--were exposed in a microcosmic system to three commonly used insecticides. The effects of the insecticides were evaluated by measuring the following molecular biomarkers-the activities of AChE, CES, CAT, GST and the concentration of GSH. The results showed that environmentally relevant doses of organophosphates dimethoate and pirimiphos-methyl significantly affected the measured biomarkers, whereas pyrethroid deltamethrin did not affect the earthworms at the recommended agricultural dose. Considering the ecological category of earthworms, the results were inhomogeneous and species-specific differences in the biomarker responses were recorded. Since the biomarker responses of the investigated earthworm species were different after exposure to organophosphates in a microcosm compared to the exposure via standardized toxicity tests, two types of species sensitivity should be distinguished-physiological and environmental sensitivity. In addition, the hormetic effect of organophosphates on AChE and CES activities was recorded. The detection of hormesis in a microcosm is of great importance for future environmental research and soil biomonitoring, since in a realistic environment pollutants usually occur at low concentrations that could cause a hormetic effect. The results demonstrate the importance of the application of microcosmic systems in the assessment of the effects of environmental pollutants and the necessity of taking into account the possible differences between physiological and environmental species sensitivity. PMID:24650551

  19. Effects of human activities on the ecological processes of river biofilms in a highly urbanized river

    NASA Astrophysics Data System (ADS)

    Hung, R.; Li, M.

    2013-12-01

    Many anthropogenic disturbances and their effects of aquatic ecosystem are difficult to quantify in urbanized rivers. In past, specific taxa analysis of community structure was a common approach in river health monitoring studies. However, it is still difficult to understand stream ecosystem integrity without considering ecosystem processes. The complex species composition and metabolism of a river biofilm have the capacity to interact and/or modulate their surrounding environment. Because of their short life cycles, species richness, and worldwide distribution, structure and function of river biofilm communities are sensitive to change in environmental conditions. Therefore, biofilms are widely used as early warning systems of water pollution for water quality monitoring studies. In this study, we used river biofilms as a bioindicator by examining their extracellular enzyme activities and photosynthesis efficiency to understand human activities on the ecological processes of river ecosystem in a highly urbanized river. We sampled four sites along the Keelung River, Taiwan, based on different intensities of anthropogenic disturbances including water pollution index, population densities, land use types and types of stream habitats. Two study sites are heavily influenced by human activities and the others are not. The activities of extracellular enzymes within the biofilm play an important function for organic matter decomposition and nutrient cycling. We measured seven extracellular enzyme activities (?-d-glucosidase, phosphatase, leucine-aminopeptidase, sulfatase, peroxidase, polyphenol oxidase, and esterase) to examine specific enzyme activity changes at four study sites monthly. In addition, relative proportion of each extracellular enzyme activity on total enzyme activities was calculated in order to examine the relationship between functional biofilm profiles and different urban intensities. Among four study sites, leucine-aminopeptidase and esterase activities constituted nearly 50% of total enzyme activities. Peroxidase and polyphenol oxidase activities were about 30% of total enzyme activities. Some extracellular enzyme activities showed seasonal variation. For example, phosphatase, peroxidase, and polyphenol oxidase activities were higher in the summer than in the winter, whereas esterase activity was lower in the summer than in the winter. The algal and cyanobacterial assemblages of river biofilms provide the main site of primary productivity in river ecosystem. Through chlorophyll a fluorescence detection, we examined the efficiency of transformation energy in photosynthesis of river biofilms. Measurements of biofilm photosynthetic efficiency showed to be below the normal level of photosynthetic efficiency among four study sites. By combining these two aspects, we discussed how biofilms were affected by different anthropogenic disturbances and hope to contribute a better understanding of river ecosystem processes for river health monitoring program.

  20. The effects of ecological restoration on CO2 fluxes from a climatically marginal upland blanket bog

    NASA Astrophysics Data System (ADS)

    Dixon, Simon; Qassim, Suzane; Rowson, James; Worrall, Fred; Evans, Martin

    2013-04-01

    A legacy of gully incision, deposition of industrially-derived aerial pollutants, inappropriate management and wildfire has left large expanses of the topographic Bleaklow Plateau (Peak District National Park, England, UK) bare of vegetation and susceptible to massive erosion of the peat soils. The consequence of such degradation has been to decrease the capacity of the peatland on the plateau to provide important ecosystem services including; loss of net C sink function, discolouration of surface waters, mobilisation to surface waters of stored heavy metals and infilling of upland reservoirs with peat-derived sediment. In response to on-going and worsening degradation a programme of ecological restoration has been undertaken. Restoration methods include: seeding with a lawn grass mix; liming; fertilisation; slope stabilisation; and gully blocking. This talk will present data from a five-year, observational-study of CO2 fluxes from eight sites, with four sites sampling different restoration treatments and four sampling bare and least disturbed areas. The results of the analysis reveal that sites with revegetation alongside slope stabilisation were most productive and were the largest net (daylight hours) sinks of CO2. Unrestored, bare sites, while having relatively low gross fluxes of CO2 were the largest net sources of CO2. Revegetation without slope stabilisation took longer (~18 months) to show an impact on CO2 flux in comparison to the sites with slope stabilisation. Binary logistic regression indicated that a ten centimetre increase in water table depth decreases the odds of observing a net CO2 sink, on a given site, by up to 30%. Sites with slope stabilisation were between 5-8x more likely to be net CO2 sinks than the bare sites. Sites without slope stabilisation were only 2-2.3x more likely to be net CO2 sinks compared to the bare sites. The most important conclusion of this research is that revegetation appears to be effective at increasing the likelihood of net CO2 behaviour on degraded, climatically marginal blanket peat, with revegetation alongside slope stabilisation having the greatest impact.

  1. Ecological Effects of Sea Level Rise: Advancing coastal management through integrated research and engagement

    NASA Astrophysics Data System (ADS)

    Kidwell, D. M.

    2012-12-01

    Rising sea level represents a significant threat to coastal communities and ecosystems through land loss, altered habitats, and increased vulnerability to coastal storms and inundation. This threat is exemplified in the northern Gulf of Mexico where low topography, expansive marshes, and a prevalence of tropical storms have already resulted in extensive coastal impacts. The development of robust predictive capabilities that incorporate complex biological processes with physical dynamics are critical for informed planning and restoration efforts for coastal ecosystems. Looking to build upon existing predictive modeling capabilities and allow for use of multiple model (i.e., ensemble) approaches, NOAA initiated the Ecological Effects of Sea Level Rise program in 2010 to advance physical/biological integrative modeling capabilities in the region with a goal to provide user friendly predictive tools for coastal ecosystem management. Focused on the northern Gulf of Mexico, this multi-disciplinary project led by the University of Central Florida will use in situ field studies to parameterize physical and biological models. These field studies will also result in a predictive capability for overland sediment delivery and transport that will further enhance marsh, oyster, and submerged aquatic vegetation models. Results from this integrated modeling effort are envisioned to inform management strategies for reducing risk, restoration and breakwater guidelines, and resource sustainability for project planning, among other uses. In addition to the science components, this project incorporates significant engagement of the management community through a management applications principle investigator and an advisory management committee. Routine engagement between the science team and the management committee, including annual workshops, are focused on ensuring the development of applicable, relevant, and useable products and tools at the conclusion of this project. Particular attention has been given to forecast and sea level rise prediction timelines and rates and methods for delivering tools and products to stakeholders and managers. Targeted manager focus groups are also being used to provide additional guidance to the science team. This presentation will provide an overview of the project with particular attention to the lessons learned through the implementation of this large-scale research project and engagement with the coastal management community.

  2. SDS, a structural disruption score for assessment of missense variant deleteriousness

    PubMed Central

    Preeprem, Thanawadee; Gibson, Greg

    2014-01-01

    We have developed a novel structure-based evaluation for missense variants that explicitly models protein structure and amino acid properties to predict the likelihood that a variant disrupts protein function. A structural disruption score (SDS) is introduced as a measure to depict the likelihood that a case variant is functional. The score is constructed using characteristics that distinguish between causal and neutral variants within a group of proteins. The SDS score is correlated with standard sequence-based deleteriousness, but shows promise for improving discrimination between neutral and causal variants at less conserved sites. The prediction was performed on 3-dimentional structures of 57 gene products whose homozygous SNPs were identified as case-exclusive variants in an exome sequencing study of epilepsy disorders. We contrasted the candidate epilepsy variants with scores for likely benign variants found in the EVS database, and for positive control variants in the same genes that are suspected to promote a range of diseases. To derive a characteristic profile of damaging SNPs, we transformed continuous scores into categorical variables based on the score distribution of each measurement, collected from all possible SNPs in this protein set, where extreme measures were assumed to be deleterious. A second epilepsy dataset was used to replicate the findings. Causal variants tend to receive higher sequence-based deleterious scores, induce larger physico-chemical changes between amino acid pairs, locate in protein domains, buried sites or on conserved protein surface clusters, and cause protein destabilization, relative to negative controls. These measures were agglomerated for each variant. A list of nine high-priority putative functional variants for epilepsy was generated. Our newly developed SDS protocol facilitates SNP prioritization for experimental validation. PMID:24795746

  3. Rare deleterious mutations of the gene EFR3A in autism spectrum disorders

    PubMed Central

    2014-01-01

    Background Whole-exome sequencing studies in autism spectrum disorder (ASD) have identified de novo mutations in novel candidate genes, including the synaptic gene Eighty-five Requiring 3A (EFR3A). EFR3A is a critical component of a protein complex required for the synthesis of the phosphoinositide PtdIns4P, which has a variety of functions at the neural synapse. We hypothesized that deleterious mutations in EFR3A would be significantly associated with ASD. Methods We conducted a large case/control association study by deep resequencing and analysis of whole-exome data for coding and splice site variants in EFR3A. We determined the potential impact of these variants on protein structure and function by a variety of conservation measures and analysis of the Saccharomyces cerevisiae Efr3 crystal structure. We also analyzed the expression pattern of EFR3A in human brain tissue. Results Rare nonsynonymous mutations in EFR3A were more common among cases (16 / 2,196?=?0.73%) than matched controls (12 / 3,389?=?0.35%) and were statistically more common at conserved nucleotides based on an experiment-wide significance threshold (P?=?0.0077, permutation test). Crystal structure analysis revealed that mutations likely to be deleterious were also statistically more common in cases than controls (P?=?0.017, Fisher exact test). Furthermore, EFR3A is expressed in cortical neurons, including pyramidal neurons, during human fetal brain development in a pattern consistent with ASD-related genes, and it is strongly co-expressed (P?deleterious mutations in EFR3A were found to be associated with ASD using an experiment-wide significance threshold. Synaptic phosphoinositide metabolism has been strongly implicated in syndromic forms of ASD. These data for EFR3A strengthen the evidence for the involvement of this pathway in idiopathic autism. PMID:24860643

  4. E-MAIL CATHERINE F. FROCK PHONE frock@wisc.edu Ecosystem and Landscape Ecology 608-265-8001 (lab)

    E-print Network

    Turner, Monica G.

    ____________________________________________________________________________________________________________________________________________________________________________ RESEARCH INTERESTS Wildlife ecology, human impacts on wildlife, landscape ecology, habitat connectivity - Concentration: Ecology, Evolution, and Conservation Biology - Honors thesis: Effects of human landscape, behavioral ecology, interspecies interactions, conservation biology, climate change, movement ecology, high

  5. Geomorphic and ecological effects of Hurricanes Katrina and Rita on coastal Louisiana marsh communities

    USGS Publications Warehouse

    Piazza, Sarai C.; Steyer, Gregory D.; Cretini, Kari F.; Sasser, Charles E.; Visser, Jenneke M.; Holm, Guerry O.; Sharp, Leigh Anne; Evers, D. Elaine; Meriwether, John R.

    2011-01-01

    Hurricanes Katrina and Rita made landfall in 2005, subjecting the coastal marsh communities of Louisiana to various degrees of exposure. We collected data after the storms at 30 sites within fresh (12), brackish/intermediate (12), and saline (6) marshes to document the effects of saltwater storm surge and sedimentation on marsh community dynamics. The 30 sites were comprised of 15 pairs. Most pairs contained one site where data collection occurred historically (that is, prestorms) and one Coastwide Reference Monitoring System site. Data were collected from spring 2006 to fall 2007 on vegetative species composition, percentage of vegetation cover, aboveground and belowground biomass, and canopy reflectance, along with discrete porewater salinity, hourly surface-water salinity, and water level. Where available, historical data acquired before Hurricanes Katrina and Rita were used to compare conditions and changes in ecological trajectories before and after the hurricanes. Sites experiencing direct and indirect hurricane influences (referred to in this report as levels of influence) were also identified, and the effects of hurricane influence were tested on vegetation and porewater data. Within fresh marshes, porewater salinity was greater in directly impacted areas, and this heightened salinity was reflected in decreased aboveground and belowground biomass and increased cover of disturbance species in the directly impacted sites. At the brackish/intermediate marsh sites, vegetation variables and porewater salinity were similar in directly and indirectly impacted areas, but porewater salinity was higher than expected throughout the study. Interestingly, directly impacted saline marsh sites had lower porewater salinity than indirectly impacted sites, but aboveground biomass was greater at the directly impacted sites. Because of the variable and site-specific nature of hurricane influences, we present case studies to help define postdisturbance baseline conditions in fresh, brackish/ intermediate, and saline marshes. In fresh marshes, the mechanism of hurricane influence varied across the landscape. In the western region, saltwater storm surge inundated freshwater marshes and remained for weeks, effectively causing damage that reset the vegetation community. This is in contrast to the direct physical disturbance of the storm surge in the eastern region, which flipped and relocated marsh mats, thereby stressing the vegetation communities and providing an opportunity for disturbance species to colonize. In the brackish/intermediate marsh, disturbance species took advantage of the opportunity provided by shifting species composition caused by physical and saltwater-induced perturbations, although this shift is likely to be short lived. Saline marsh sites were not negatively impacted to a severe degree by the hurricanes. Species composition of vegetation in saline marshes was not affected, and sediment deposition appeared to increase vegetative productivity. The coastal landscape of Louisiana is experiencing high rates of land loss resulting from natural and anthropogenic causes and is experiencing subsidence rates greater than 10.0 millimeters per year (mm yr-1); therefore, it is important to understand how hurricanes influence sedimentation and soil properties. We document long-term vertical accretion rates and accumulation rates of organic matter, bulk density, carbon and nitrogen. Analyses using caesium-137 to calculate long-term vertical accretion rates suggest that accretion under impounded conditions is less than in nonimpounded conditions in the brackish marsh of the chenier plain. Our data also support previous studies indicating that accumulation rates of organic matter explain much of the variability associated with vertical accretion in brackish/intermediate and saline marshes. In fresh marshes, more of the variability associated with vertical accretion was explained by mineral accumulation than in the other mars

  6. Evolution- and Structure-Based Computational Strategy Reveals the Impact of Deleterious Missense Mutations on MODY 2 (Maturity-Onset Diabetes of the Young, Type 2)

    PubMed Central

    George, Doss C. Priya; Chakraborty, Chiranjib; Haneef, SA Syed; NagaSundaram, Nagarajan; Chen, Luonan; Zhu, Hailong

    2014-01-01

    Heterozygous mutations in the central glycolytic enzyme glucokinase (GCK) can result in an autosomal dominant inherited disease, namely maturity-onset diabetes of the young, type 2 (MODY 2). MODY 2 is characterised by early onset: it usually appears before 25 years of age and presents as a mild form of hyperglycaemia. In recent years, the number of known GCK mutations has markedly increased. As a result, interpreting which mutations cause a disease or confer susceptibility to a disease and characterising these deleterious mutations can be a difficult task in large-scale analyses and may be impossible when using a structural perspective. The laborious and time-consuming nature of the experimental analysis led us to attempt to develop a cost-effective computational pipeline for diabetic research that is based on the fundamentals of protein biophysics and that facilitates our understanding of the relationship between phenotypic effects and evolutionary processes. In this study, we investigate missense mutations in the GCK gene by using a wide array of evolution- and structure-based computational methods, such as SIFT, PolyPhen2, PhD-SNP, SNAP, SNPs&GO, fathmm, and Align GVGD. Based on the computational prediction scores obtained using these methods, three mutations, namely E70K, A188T, and W257R, were identified as highly deleterious on the basis of their effects on protein structure and function. Using the evolutionary conservation predictors Consurf and Scorecons, we further demonstrated that most of the predicted deleterious mutations, including E70K, A188T, and W257R, occur in highly conserved regions of GCK. The effects of the mutations on protein stability were computed using PoPMusic 2.1, I-mutant 3.0, and Dmutant. We also conducted molecular dynamics (MD) simulation analysis through in silico modelling to investigate the conformational differences between the native and the mutant proteins and found that the identified deleterious mutations alter the stability, flexibility, and solvent-accessible surface area of the protein. Furthermore, the functional role of each SNP in GCK was identified and characterised using SNPeffect 4.0, F-SNP, and FASTSNP. We hope that the observed results aid in the identification of disease-associated mutations that affect protein structure and function. Our in silico findings provide a new perspective on the role of GCK mutations in MODY2 from an evolution-based structure-centric point of view. The computational architecture described in this paper can be used to predict the most appropriate disease phenotypes for large-genome sequencing projects and to provide individualised drug therapy for complex diseases such as diabetes. PMID:24578721

  7. Effects of fragmentation on the spatial ecology of the California Kingsnake (Lampropeltis californiae)

    USGS Publications Warehouse

    Anguiano, Michael P.; Diffendorfer, James E.

    2015-01-01

    We investigated the spatial ecology of the California Kingsnake (Lampropeltis californiae) in unfragmented and fragmented habitat with varying patch sizes and degrees of exposure to urban edges. We radiotracked 34 Kingsnakes for up to 3 yr across four site types: interior areas of unfragmented ecological reserves, the urbanized edge of these reserves, large habitat fragments, and small habitat fragments. There was no relationship between California Kingsnake movements and the degree of exposure to urban edges and fragmentation. Home range size and movement patterns of Kingsnakes on edges and fragments resembled those in unfragmented sites. Average home-range size on each site type was smaller than the smallest fragment in which snakes were tracked. The persistence of California Kingsnakes in fragmented landscapes may be related directly to their small spatial movement patterns, home-range overlap, and ability to use urban edge habitat.

  8. Effects of ground water exchange on the hydrology and ecology of surface water.

    PubMed

    Hayashi, Masaki; Rosenberry, Donald O

    2002-01-01

    Ground water exchange affects the ecology of surface water by sustaining stream base flow and moderating water-level fluctuations of ground water-fed lakes. It also provides stable-temperature habitats and supplies nutrients and inorganic ions. Ground water input of nutrients can even determine the trophic status of lakes and the distribution of macrophytes. In streams the mixing of ground water and surface water in shallow channel and bankside sediments creates a unique environment called the hyporheic zone, an important component of the lotic ecosystem. Localized areas of high ground water discharge in streams provide thermal refugia for fish. Ground water also provides moisture to riparian vegetation, which in turn supplies organic matter to streams and enhances bank resistance to erosion. As hydrologists and ecologists interact to understand the impact of ground water on aquatic ecology, a new research field called "ecohydrology" is emerging. PMID:12019646

  9. Relative Effectiveness of Expository and Field Trip Methods of Teaching on Students' Achievement in Ecology

    ERIC Educational Resources Information Center

    Hamilton-Ekeke, Joy-Telu

    2007-01-01

    The study was a pre-test treatment post-test control design. Three educational districts from the Niger Delta region of Nigeria were treated as clusters. Twenty boys and 20 girls were randomly selected, making up a total of 40 students, in each of Group A, Group B, and Group C. Students in Group A were taught ecology by taking them to the school…

  10. The Effect of Inappropriate Calibration: Three Case Studies in Molecular Ecology

    PubMed Central

    Ho, Simon Y. W.; Saarma, Urmas; Barnett, Ross; Haile, James; Shapiro, Beth

    2008-01-01

    Time-scales estimated from sequence data play an important role in molecular ecology. They can be used to draw correlations between evolutionary and palaeoclimatic events, to measure the tempo of speciation, and to study the demographic history of an endangered species. In all of these studies, it is paramount to have accurate estimates of time-scales and substitution rates. Molecular ecological studies typically focus on intraspecific data that have evolved on genealogical scales, but often these studies inappropriately employ deep fossil calibrations or canonical substitution rates (e.g., 1% per million years for birds and mammals) for calibrating estimates of divergence times. These approaches can yield misleading estimates of molecular time-scales, with significant impacts on subsequent evolutionary and ecological inferences. We illustrate this calibration problem using three case studies: avian speciation in the late Pleistocene, the demographic history of bowhead whales, and the Pleistocene biogeography of brown bears. For each data set, we compare the date estimates that are obtained using internal and external calibration points. In all three cases, the conclusions are significantly altered by the application of revised, internally-calibrated substitution rates. Collectively, the results emphasise the importance of judicious selection of calibrations for analyses of recent evolutionary events. PMID:18286172

  11. Cumulative effects of restoration efforts on ecological characteristics of an open water area within the Upper Mississippi River

    USGS Publications Warehouse

    Gray, B.R.; Shi, W.; Houser, J.N.; Rogala, J.T.; Guan, Z.; Cochran-Biederman, J. L.

    2011-01-01

    Ecological restoration efforts in large rivers generally aim to ameliorate ecological effects associated with large-scale modification of those rivers. This study examined whether the effects of restoration efforts-specifically those of island construction-within a largely open water restoration area of the Upper Mississippi River (UMR) might be seen at the spatial scale of that 3476ha area. The cumulative effects of island construction, when observed over multiple years, were postulated to have made the restoration area increasingly similar to a positive reference area (a proximate area comprising contiguous backwater areas) and increasingly different from two negative reference areas. The negative reference areas represented the Mississippi River main channel in an area proximate to the restoration area and an open water area in a related Mississippi River reach that has seen relatively little restoration effort. Inferences on the effects of restoration were made by comparing constrained and unconstrained models of summer chlorophyll a (CHL), summer inorganic suspended solids (ISS) and counts of benthic mayfly larvae. Constrained models forced trends in means or in both means and sampling variances to become, over time, increasingly similar to those in the positive reference area and increasingly dissimilar to those in the negative reference areas. Trends were estimated over 12- (mayflies) or 14-year sampling periods, and were evaluated using model information criteria. Based on these methods, restoration effects were observed for CHL and mayflies while evidence in favour of restoration effects on ISS was equivocal. These findings suggest that the cumulative effects of island building at relatively large spatial scales within large rivers may be estimated using data from large-scale surveillance monitoring programs. Published in 2010 by John Wiley & Sons, Ltd.

  12. Inherited deleterious variants in GALNT12 are associated with CRC susceptibility.

    PubMed

    Clarke, Erica; Green, Roger C; Green, Jane S; Mahoney, Krista; Parfrey, Patrick S; Younghusband, H Banfield; Woods, Michael O

    2012-07-01

    A recent report detailed the occurrence of both somatic and constitutional variants in the GALNT12 gene, located at 9q22.33, in some colorectal cancer (CRC) patients. In this study, we investigate the occurrence of inherited deleterious variants in GALNT12 in 118 families referred to a cancer genetics clinic. We discovered two deleterious variants (c.907G>A (p.Asp303Asn); c.1187A>G (p.Tyr396Cys)) in 4/118 probands. The variants, which were not found in 149 control individuals (P = 0.0376), cosegregate with CRC and/or adenomatous polyps in other family members. The probability by chance that cosegregation of c.907G>A with CRC and/or adenomatous polyps occurred, in the two pedigrees combined, was 1.56%. Although this study does not provide irrefutable evidence that GALNT12 variants are highly penetrant alleles that predispose to CRC in the majority of unexplained hereditary CRC families, it does provide additional evidence to support an important role of these variants in a proportion of this considerable high-risk group. PMID:22461326

  13. Metabolic ecology.

    PubMed

    Humphries, Murray M; McCann, Kevin S

    2014-01-01

    Ecological theory that is grounded in metabolic currencies and constraints offers the potential to link ecological outcomes to biophysical processes across multiple scales of organization. The metabolic theory of ecology (MTE) has emphasized the potential for metabolism to serve as a unified theory of ecology, while focusing primarily on the size and temperature dependence of whole-organism metabolic rates. Generalizing metabolic ecology requires extending beyond prediction and application of standardized metabolic rates to theory focused on how energy moves through ecological systems. A bibliometric and network analysis of recent metabolic ecology literature reveals a research network characterized by major clusters focused on MTE, foraging theory, bioenergetics, trophic status, and generalized patterns and predictions. This generalized research network, which we refer to as metabolic ecology, can be considered to include the scaling, temperature and stoichiometric models forming the core of MTE, as well as bioenergetic equations, foraging theory, life-history allocation models, consumer-resource equations, food web theory and energy-based macroecology models that are frequently employed in ecological literature. We conclude with six points we believe to be important to the advancement and integration of metabolic ecology, including nomination of a second fundamental equation, complementary to the first fundamental equation offered by the MTE. PMID:24028511

  14. A synthesis of the ecological effects of air pollution from nitrogen and sulfur in the U.S

    USGS Publications Warehouse

    Greaver, T.L.; Sullivan, T.; Herrick, J.D.; Barber, M.; Baron, J.; Cosby, B.; Deerharke, M.; Dennis, R.; Dubois, J.J.D.; Goodale, C.; Herlihy, A.; Lawrence, G.; Liu, L.; Lynch, J.; Novak, K.

    2012-01-01

    Four decades after the passage of the US Clean Air Act, air-quality standards are set to protect ecosystems from damage caused by gas-phase nitrogen (N) and sulfur (S) compounds, but not from the deposition of these air pollutants to land and water. Here, we synthesize recent scientific literature on the ecological effects of N and S air pollution in the US. Deposition of N and S is the main driver of ecosystem acidification and contributes to nutrient enrichment in many natural systems. Although surface-water acidification has decreased in the US since 1990, it remains a problem in many regions. Perturbations to ecosystems caused by the nutrient effects of N deposition continue to emerge, although gas-phase concentrations are generally not high enough to cause phytotoxicity. In all, there is overwhelming evidence of a broad range of damaging effects to ecosystems in the US under current air quality conditions.

  15. Ecology has contrasting effects on genetic variation within species versus rates of molecular evolution across species in water beetles.

    PubMed

    Fujisawa, Tomochika; Vogler, Alfried P; Barraclough, Timothy G

    2015-01-22

    Comparative analysis is a potentially powerful approach to study the effects of ecological traits on genetic variation and rate of evolution across species. However, the lack of suitable datasets means that comparative studies of correlates of genetic traits across an entire clade have been rare. Here, we use a large DNA-barcode dataset (5062 sequences) of water beetles to test the effects of species ecology and geographical distribution on genetic variation within species and rates of molecular evolution across species. We investigated species traits predicted to influence their genetic characteristics, such as surrogate measures of species population size, latitudinal distribution and habitat types, taking phylogeny into account. Genetic variation of cytochrome oxidase I in water beetles was positively correlated with occupancy (numbers of sites of species presence) and negatively with latitude, whereas substitution rates across species depended mainly on habitat types, and running water specialists had the highest rate. These results are consistent with theoretical predictions from nearly-neutral theories of evolution, and suggest that the comparative analysis using large databases can give insights into correlates of genetic variation and molecular evolution. PMID:25621335

  16. The spatial ecology of Eastern Hognose Snakes (Heterodon platirhinos): habitat selection, home range size, and the effect of roads on movement

    E-print Network

    Blouin-Demers, Gabriel

    edits came back to me quicker than the speed of light and often before a (much needed) night's sleep range size, and the effect of roads on movement patterns Laura Elizabeth Robson Thesis management and recovery. I conducted a radiotelemetry study to examine the spatial ecology and the effects

  17. General Ecology

    NSDL National Science Digital Library

    This tutorial explains how environmental conditions and organism interactions determine animal and tree distribution and abundance. There are definitions of important ecological terms such as ecology, interactions, and abundance; descriptions of the environmental conditions needed for rainforests and how they provide habitat for many species; and an explanation of the spawning process. The tutorial also introduces food chain concepts and the unique ecology of riparian habitats. A quiz is also available.

  18. The effects of ecology and evolutionary history on robust capuchin morphological diversity.

    PubMed

    Wright, Kristin A; Wright, Barth W; Ford, Susan M; Fragaszy, Dorothy; Izar, Patricia; Norconk, Marilyn; Masterson, Thomas; Hobbs, David G; Alfaro, Michael E; Lynch Alfaro, Jessica W

    2015-01-01

    Recent molecular work has confirmed the long-standing morphological hypothesis that capuchins are comprised of two distinct clades, the gracile (untufted) capuchins (genus Cebus, Erxleben, 1777) and the robust (tufted) capuchins (genus Sapajus Kerr, 1792). In the past, the robust group was treated as a single, undifferentiated and cosmopolitan species, with data from all populations lumped together in morphological and ecological studies, obscuring morphological differences that might exist across this radiation. Genetic evidence suggests that the modern radiation of robust capuchins began diversifying ?2.5 Ma, with significant subsequent geographic expansion into new habitat types. In this study we use a morphological sample of gracile and robust capuchin craniofacial and postcranial characters to examine how ecology and evolutionary history have contributed to morphological diversity within the robust capuchins. We predicted that if ecology is driving robust capuchin variation, three distinct robust morphotypes would be identified: (1) the Atlantic Forest species (Sapajus xanthosternos, S. robustus, and S. nigritus), (2) the Amazonian rainforest species (S. apella, S. cay and S. macrocephalus), and (3) the Cerrado-Caatinga species (S. libidinosus). Alternatively, if diversification time between species pairs predicts degree of morphological difference, we predicted that the recently diverged S. apella, S. macrocephalus, S. libidinosus, and S. cay would be morphologically comparable, with greater variation among the more ancient lineages of S. nigritus, S. xanthosternos, and S. robustus. Our analyses suggest that S. libidinosus has the most derived craniofacial and postcranial features, indicative of inhabiting a more terrestrial niche that includes a dependence on tool use for the extraction of imbedded foods. We also suggest that the cranial robusticity of S. macrocephalus and S. apella are indicative of recent competition with sympatric gracile capuchin species, resulting in character displacement. PMID:25194323

  19. [Formation of iron plaque on root surface and its effect on plant nutrition and ecological environment].

    PubMed

    He, Chun'e; Liu, Xuejun; Zhang, Fusuo

    2004-06-01

    This paper illustrated the conditions of iron plaque formation on root surface, the morphology, mineralogical composition and deposition site of the plaque, and its function as a Fe reservoir in supplying Fe nutrient and affecting the uptake of other nutrients such as phosphorus and zinc. The environmental and ecological role of the plaque in inhibiting the uptake and translocation of heavy metals such as Cu, Ni, Cd and As through absorption or co-precipitation was called external tolerance mechanism, while its competition with heavy metals for metabolically sensitive sites in plants was called internal tolerance mechanisms. These two mechanisms help plant survive in high acidic and low carbon environment. PMID:15362637

  20. Global Ecology

    SciTech Connect

    Southwich, C.H.

    1985-01-01

    Global Ecology is a collection of recent papers and original essays which explore the biosphere - its nature, extent, functional properties and current condition. The essays consider ecological principles and problems on a worldwide basis and grapple with difficult questions concerning man's future prospects. Many chapters however, while acknowledging dangerous and discouraging trends, point in positive directions if science and human affairs can be properly utilized and managed. The book provides supplementary material for use with standard textbooks of ecology or environmental science; it may also be used as the basis for an entire course in global ecology.

  1. DELETERIOUS IMPACT OF ?-AMINOBUTYRIC ACID TYPE A RECEPTOR PREFERRING GENERAL ANESTHETIC WHEN USED IN THE PRESENCE OF PERSISTENT INFLAMMATION

    PubMed Central

    Boegel, Kevin; Gyulai, Ferenc E.; Moore, Kerry; Gold, Michael S.

    2011-01-01

    Background Experimental data suggest ?-aminobutyric acid-A receptor preferring general anesthetics (GA) may increase post-operative pain in patients with persistent inflammation (PI). This study was designed to begin to test this prediction. Methods Groups of rats were defined by the presence of inflammation, surgical intervention and/or the type of GA used for a three-hour period of anesthesia. PI was induced with complete Freund's adjuvant. The surgical intervention was a plantar incision. Three mechanistically distinct GAs were used: pentobarbital, ketamine/xylazine and isoflurane. Ongoing pain and hypersensitivity was assessed with guarding behavior analysis and the von Frey test, respectively. Results There was no influence of GA type on the magnitude or time course of recovery from post-operative hypersensitivity in the absence of PI. In the presence of PI, however, recovery from hypersensitivity was significantly slower in the pentobarbital group than in ketamine/xylazine or isoflurane groups. The pentobarbital effect was significant within three days of surgery, and persisted through the remainder of the testing period. A comparable delay in recovery was observed in pentobarbital-anesthetized inflamed rats not subjected to hindpaw incision. The time to 50% recovery in pentobarbital treated inflamed groups was almost double that in the other groups. No differences were observed between ketamine/xylazine and isoflurane. Pentobarbital exposure did not increase guarding scores. Conclusions These results suggest that ?-aminobutyric acid-A receptor preferring GAs may have deleterious consequences when used in the presence of PI. PMID:21841466

  2. Migration intensity has no effect on peak HIV prevalence: an ecological study

    PubMed Central

    2014-01-01

    Background Correctly identifying the determinants of generalized HIV epidemics is crucial to bringing down ongoing high HIV incidence in these countries. High rates of migration are believed to be an important determinant of HIV prevalence. This study has two aims. Firstly, it evaluates the ecological association between levels of internal and international migration and national peak HIV prevalence using thirteen variables from a variety of sources to capture various aspects of internal and international migration intensity. Secondly, it examines the relationship between circular migration and HIV at an individual and population-level in South Africa. Methods Linear regression was used to analyze the association between the various measures of migration intensity and peak national HIV prevalence for 141 countries and HIV prevalence by province and ethnic group in South Africa. Results No evidence of a positive ecological association between national migration intensity and HIV prevalence was found. This remained the case when the analyses were limited to the countries of sub-Saharan Africa. On the whole, countries with generalized HIV epidemics had lower rates of internal and external migration. Likewise, no association was found between migration and HIV positivity at an individual or group-level in South Africa. Conclusion These results do not support the thesis that migration measured at the country level plays a significant role in determining peak HIV prevalence. PMID:24961725

  3. Quantifying rare, deleterious variation in 12 human cytochrome P450 drug-metabolism genes in a large-scale exome dataset.

    PubMed

    Gordon, Adam S; Tabor, Holly K; Johnson, Andrew D; Snively, Beverly M; Assimes, Themistocles L; Auer, Paul L; Ioannidis, John P A; Peters, Ulrike; Robinson, Jennifer G; Sucheston, Lara E; Wang, Danxin; Sotoodehnia, Nona; Rotter, Jerome I; Psaty, Bruce M; Jackson, Rebecca D; Herrington, David M; O'Donnell, Christopher J; Reiner, Alexander P; Rich, Stephen S; Rieder, Mark J; Bamshad, Michael J; Nickerson, Deborah A

    2014-04-15

    The study of genetic influences on drug response and efficacy ('pharmacogenetics') has existed for over 50 years. Yet, we still lack a complete picture of how genetic variation, both common and rare, affects each individual's responses to medications. Exome sequencing is a promising alternative method for pharmacogenetic discovery as it provides information on both common and rare variation in large numbers of individuals. Using exome data from 2203 AA and 4300 Caucasian individuals through the NHLBI Exome Sequencing Project, we conducted a survey of coding variation within 12 Cytochrome P450 (CYP) genes that are collectively responsible for catalyzing nearly 75% of all known Phase I drug oxidation reactions. In addition to identifying many polymorphisms with known pharmacogenetic effects, we discovered over 730 novel nonsynonymous alleles across the 12 CYP genes of interest. These alleles include many with diverse functional effects such as premature stop codons, aberrant splicesites and mutations at conserved active site residues. Our analysis considering both novel, predicted functional alleles as well as known, actionable CYP alleles reveals that rare, deleterious variation contributes markedly to the overall burden of pharmacogenetic alleles within the populations considered, and that the contribution of rare variation to this burden is over three times greater in AA individuals as compared with Caucasians. While most of these impactful alleles are individually rare, 7.6-11.7% of individuals interrogated in the study carry at least one newly described potentially deleterious alleles in a major drug-metabolizing CYP. PMID:24282029

  4. Ecological effects on streams from forest fertilization; literature review and conceptual framework for future study in the western Cascades

    USGS Publications Warehouse

    Anderson, C.W.

    2002-01-01

    Studies of the responses of stream biota to fertilization have been rare and have targeted either immediate, toxicity-based responses or used methods insensitive to ongoing ecological processes. This report reviews water-quality studies following forest fertilizations, emphasizing Cascade streams in the Pacific Northwest and documented biological responses in those streams. A conceptual model predicting potential ecological response to fertilization, which includes effects on algal growth and primary production, is presented. In this model, applied fertilizer nitrogen reaching streams is mostly exported during winter. However, some nitrogen retained in soils or stream and riparian areas may become available to aquatic biota during spring and summer. Biological responses may be minimal in small streams nearest to application because of light limitation, but may be elevated downstream where light is sufficient to allow algal growth. Ultimately, algal response could be greatest in downstream reaches, although ambient nutrient concentrations remain low due to uptake and benthic nutrient recycling. Ground-water flow paths and hyporheic processing could be critical in determining the fate of applied nitrogen. A framework is provided for testing this response in the Little River watershed, a tributary to the North Umpqua River, Oregon, at basic and intensive levels of investigation.

  5. The Effects of Local Ecological Knowledge, Minimum-Impact Knowledge, and Prior Experience on Visitor Perceptions of the Ecological Impacts of Backcountry Recreation

    NASA Astrophysics Data System (ADS)

    D'Antonio, Ashley; Monz, Christopher; Newman, Peter; Lawson, Steve; Taff, Derrick

    2012-10-01

    An on-site visitor survey instrument was developed to examine visitor perceptions of resource impacts resulting from backcountry hiking activities. The survey was conducted in the Bear Lake Corridor of Rocky Mountain National Park, CO and examined visitor characteristics that may influence visitor perceptions of specific resource conditions. Findings indicate that visitors are more perceptive of recreation-related resource impacts that are the result of undesirable behavior and, while visitors do perceive resource impacts, visitors tend to be more affected by crowding. Factors such as local ecological knowledge and knowledge of minimal-impact practices positively influence visitor perceptions of resource impacts. These findings support the use of visitor education on ecological knowledge and minimum-impact as a means of increasing visitor awareness of recreation impact issues.

  6. Deleterious mutations at the mitochondrial ND3 gene in South American marsh rats (Holochilus).

    PubMed Central

    Kennedy, P; Nachman, M W

    1998-01-01

    Statistical analyses of DNA sequences have revealed patterns of nonneutral evolution in mitochondrial DNA of mice, humans, and Drosophila. Here we report patterns of mitochondrial sequence evolution in South American marsh rats (genus Holochilus). We sequenced the complete mitochondrial ND3 gene in 82 Holochilus brasiliensis and 21 H. vulpinus to test the neutral prediction that the ratio of nonsynonymous to synonymous nucleotide changes is the same within and between species. Within H. brasiliensis we observed a greater number of amino acid polymorphisms than expected based on interspecific comparisons. This contingency table analysis suggests that many amino acid polymorphisms are mildly deleterious. Several tests of the frequency distribution also revealed departures from a neutral, equilibrium model, and these departures were observed for both nonsynonymous and synonymous sites. In general, an excess of rare sites was observed, consistent with either a recent selective sweep or with populations not at mutation-drift equilibrium. PMID:9725852

  7. Ecological Autobiography.

    ERIC Educational Resources Information Center

    Wilson, Ruth A.

    1995-01-01

    Discusses the use of the ecological autobiography as a tool for enhancing an understanding of one's self and the human-earth relationship. Presents a five-step process for developing one's own ecological autobiography and suggestions on how to make the development of autobiographical essays a part of environmental education programs. Contains 28…

  8. Ecological Consultancy

    ERIC Educational Resources Information Center

    Wilson, Scott McG.; Tattersfield, Peter

    2004-01-01

    This is the first of a new regular feature on careers, designed to provide those who teach biology with some inspiration when advising their students. In this issue, two consultant ecologists explain how their career paths developed. It is a misconception that there are few jobs in ecology. Over the past 20 or 30 years ecological consultancy has…

  9. [Ecological effect of hygroscopic and condensate water on biological soil crusts in Shapotou region of China].

    PubMed

    Pan, Yan-Xia; Wang, Xin-Ping; Zhang, Ya-Feng; Hu, Rui

    2013-03-01

    By the method of field experiment combined with laboratory analysis, this paper studied the ecological significance of hygroscopic and condensate water on the biological soil crusts in the vegetation sand-fixing area in Shapotou region of China. In the study area, 90% of hygroscopic and condensate water was within the 3 cm soil depth, which didn' t affect the surface soil water content. The hygroscopic and condensate water generated at night involved in the exchange process of soil surface water and atmosphere water vapor, made up the loss of soil water due to the evaporation during the day, and made the surface soil water not reduced rapidly. The amount of the generated hygroscopic and condensate water had a positive correlation with the chlorophyll content of biological soil crusts, indicating that the hygroscopic and condensate water could improve the growth activity of the biological soil crusts, and thus, benefit the biomass accumulation of the crusts. PMID:23755477

  10. Effects of environmental change on zoonotic disease risk: an ecological primer.

    PubMed

    Estrada-Peña, Agustín; Ostfeld, Richard S; Peterson, A Townsend; Poulin, Robert; de la Fuente, José

    2014-04-01

    Impacts of environmental changes on zoonotic disease risk are the subject of speculation, but lack a coherent framework for understanding environmental drivers of pathogen transmission from animal hosts to humans. We review how environmental factors affect the distributions of zoonotic agents and their transmission to humans, exploring the roles they play in zoonotic systems. We demonstrate the importance of capturing the distributional ecology of any species involved in pathogen transmission, defining the environmental conditions required, and the projection of that niche onto geography. We further review how environmental changes may alter the dispersal behaviour of populations of any component of zoonotic disease systems. Such changes can modify relative importance of different host species for pathogens, modifying contact rates with humans. PMID:24636356

  11. Workshop on Closed System Ecology

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Self maintaining laboratory scale ecological systems completely isolated from exchanges of matter with external systems were demonstrated. These research tools are discussed in terms of their anticipated value in understanding (1) global ecological material and energy balances, (2) the dynamics of stability and instability in ecosystems, (3) the effects of man-made substances and structures on ecosystems, and (4) the precise requirements for dynamic control of controlled ecology life support systems (CELSS).

  12. Computational Screening and Molecular Dynamic Simulation of Breast Cancer Associated Deleterious Non-Synonymous Single Nucleotide Polymorphisms in TP53 Gene

    PubMed Central

    Chitrala, Kumaraswamy Naidu; Yeguvapalli, Suneetha

    2014-01-01

    Breast cancer is one of the most common cancers among the women around the world. Several genes are known to be responsible for conferring the susceptibility to breast cancer. Among them, TP53 is one of the major genetic risk factor which is known to be mutated in many of the breast tumor types. TP53 mutations in breast cancer are known to be related to a poor prognosis and chemo resistance. This renders them as a promising molecular target for the treatment of breast cancer. In this study, we present a computational based screening and molecular dynamic simulation of breast cancer associated deleterious non-synonymous single nucleotide polymorphisms in TP53. We have predicted three deleterious coding non-synonymous single nucleotide polymorphisms rs11540654 (R110P), rs17849781 (P278A) and rs28934874 (P151T) in TP53 with a phenotype in breast tumors using computational tools SIFT, Polyphen-2 and MutDB. We have performed molecular dynamics simulations to study the structural and dynamic effects of these TP53 mutations in comparison to the wild-type protein. Results from our simulations revealed a detailed consequence of the mutations on the p53 DNA-binding core domain that may provide insight for therapeutic approaches in breast cancer. PMID:25105660

  13. Ethical issues surrounding do not attempt resuscitation orders: decisions, discussions and deleterious effects

    Microsoft Academic Search

    Zoë Fritz; Jonathan Fuld

    2010-01-01

    Since their introduction as ‘no code’ in the 1980s and their later formalisation to ‘do not resuscitate’ orders, such directions to withhold potentially life-extending treatments have been accompanied by multiple ethical issues. The arguments for when and why to instigate such orders are explored, including a consideration of the concept of futility, allocation of healthcare resources, and reaching a balance

  14. Oral N-acetylcysteine has a deleterious effect in acute iron intoxication in rats.

    PubMed

    Abu-Kishk, Ibrahim; Kozer, Eran; Goldstein, Lee H; Weinbaum, Sarit; Bar-Haim, Adina; Alkan, Yoav; Petrov, Irena; Evans, Sandra; Siman-Tov, Yariv; Berkovitch, Matitiahu

    2010-01-01

    Acute iron intoxication is associated with depletion of reduced glutathione in hepatocytes and changes in the glutathione system enzymes. We hypothesized that treatment with N-acetylcysteine (NAC), a glutathione reducing agent and an antioxidant, would reduce mortality in acute iron intoxication. We used a rat model to test this hypothesis. Male rats were assigned to 4 groups. Group 1 received 400 mg/kg elemental iron by oral gavage, group 2 received the same dose of iron followed by NAC, group 3 received NAC only, whereas group 4 received distilled water. Iron and liver transaminases in the blood, and glutathione system enzymes in the liver and erythrocytes were measured. Mortality in group 2 was significantly higher after 2, 6, and 24 hours compared with group 1 (P < .001). No deaths were observed in groups 3 and 4. Serum iron levels were significantly higher in group 2 rats compared to group 1 rats (P < .001). Hepatic and erythrocyte glutathione system enzymes were significantly lower among rats in group 2 compared to rats in group 1. The administration of NAC probably increased the absorption of iron through the gastrointestinal tract, causing higher serum iron levels with significant hepatic damage. These results indicate that in a rat model of acute iron intoxication, orally administered NAC may increase mortality. PMID:20006194

  15. Infective Endocarditis Due to Staphylococcus aureus Deleterious Effect of Anticoagulant Therapy

    Microsoft Academic Search

    Pilar Tornos; Benito Almirante; Sonia Mirabet; Gaieta Permanyer; Albert Pahissa; Jordi Soler-Soler

    1999-01-01

    Background: The use of anticoagulant therapy in pa- tients with infective endocarditis (IE) is a controversial issue. Objective: To study the impact of anticoagulant therapy on the clinical outcome, mortality, and cause of death in a series of patients with native and prosthetic left- sided Staphylococcus aureus IE. Methods: This report is based on all consecutive cases of IE diagnosed

  16. Optical spectroscopy and prevention of deleterious cerebral vascular effects of ethanol by magnesium ions

    Microsoft Academic Search

    Randall L. Barbour; Asefa Gebrewold; Bella T. Altura; Burton M. Altura

    2002-01-01

    Previously, it has been suggested that acute ethanol (alcohol) administration can result in concentration-dependent vasoconstriction and decreased cerebral blood flow. Here, we present in vivo results using rapid (240 nm\\/min) optical backscatter measurements, with an intact cranial preparation in the rat, indicating that acute infusion of ethanol directly into the rat brain rapidly produces dose-dependent vasoconstriction of the cerebral microcirculation

  17. Multiple deleterious effects of experimentally aged sperm in a monogamous bird

    E-print Network

    Richner, Heinz

    the impact of sperm aging on black-legged kittiwakes (Rissa tridac- tyla), a monogamous seabird. Kittiwakes manipulated the age of the sperm fertilizing kittiwake eggs by fitting males with anti-insemination rings for variable periods of time preceding egg-laying. We found evidence that sperm aging negatively af- fected

  18. Trimetazidine Reverses Deleterious Effects of Ischemia-Reperfusion in the Isolated Perfused Pig Kidney Model

    Microsoft Academic Search

    Thierry Hauet; Denis Mothes; Jean-Michel Goujon; Thierry Germonville; Jean Claude Caritez; Michel Carretier; Michel Eugene; Jean-Paul Tillement

    1998-01-01

    Background: Delayed graft function has remained an important complication after renal transplantation. Methods: The purpose of this study was to evaluate Euro-Collins (EC) plus trimetazidine (TMZ) in comparison with standard EC solution after 24- or 48-hour cold storage. The normothermic isolated perfused pig kidney technique combined with proton nuclear magnetic spectroscopy was used. Results: The study verified that TMZ plus

  19. RAGE: The beneficial and deleterious effects by diverse mechanisms of actions

    Microsoft Academic Search

    Sun-Ho Han; Yoon Hee Kim; Inhee Mook-Jung

    2011-01-01

    Receptor for advanced glycation endproducts (RAGE) is a transmembrane protein that belongs to the immunoglobulin superfamily.\\u000a RAGE is expressed ubiquitously-high in lung and moderate to low in a wide range of cells-in a tightly regulated manner at\\u000a various stages of development. RAGE is a pattern recognition receptor that binds to multiple ligands, including amphoterin,\\u000a members of the S100\\/calgranulin family, the

  20. Deleterious Thermal Effects due to Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    NASA Technical Reports Server (NTRS)

    Moran, Robert P.

    2013-01-01

    Reactor fuel rod surface area that is perpendicular to coolant flow direction (+S) i.e. perpendicular to the P creates areas of coolant stagnation leading to increased coolant temperatures resulting in localized changes in fluid properties. Changes in coolant fluid properties caused by minor increases in temperature lead to localized reductions in coolant mass flow rates leading to localized thermal instabilities. Reductions in coolant mass flow rates result in further increases in local temperatures exacerbating changes to coolant fluid properties leading to localized thermal runaway. Unchecked localized thermal runaway leads to localized fuel melting. Reactor designs with randomized flow paths are vulnerable to localized thermal instabilities, localized thermal runaway, and localized fuel melting.

  1. Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    NASA Technical Reports Server (NTRS)

    Moran, Robert P.

    2013-01-01

    A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

  2. An Ecological Risk Assessment Framework for Effects of Onsite Wastewater Treatment Systems and Other Localized Sources of Nutrients on Aquatic Ecosystems

    Microsoft Academic Search

    Rebecca A. Efroymson; Daniel S. Jones; Arthur J. Gold

    2007-01-01

    An ecological risk assessment framework for onsite wastewater treatment systems and other localized sources of nutrients is presented, including problem formulation, characterization of exposure, characterization of effects, and risk characterization. The framework is most pertinent to the spatial scale of residential treatment systems located adjacent to small ponds, streams, or lagoons and some parts of shallow estuaries. Freshwater and estuarine

  3. Survival in a long-lived territorial migrant: effects of life-history traits and ecological conditions in wintering and breeding areas

    E-print Network

    Carrete, Martina

    of global climate change. Survival rate is one of the principal demographic parameters determiningSurvival in a long-lived territorial migrant: effects of life-history traits and ecological explain variability in survival in a migratory Spanish population of a long-lived territorial species

  4. Ecology 2006 94, 815824

    E-print Network

    Berkowitz, Alan R.

    Ecological Society Blackwell Publishing Ltd Predictability of ecosystem engineering effects on species patches, the presence of patches created by an ecosystem engineer should increase species richness landscape-level effect of ecosystem engineering on species richness is growing (Wright et al. 2002; Lill

  5. Aquatic Ecology Aquatic ecology group studies ecological interactions

    E-print Network

    Aquatic Ecology Aquatic ecology group studies ecological interactions between biota and their environment in freshwater and marine ecosystems. The group focuses particularly on the ecological interactions and their underlying ecological processes necessary to sustain ecosystem structure and function in their natural state

  6. Ecological Footprints

    NSDL National Science Digital Library

    Ever wondered what sort of impact your everyday existence has on the planet? The University of Texas at Austin offers this information as part of their training in Natural Resource Management. An ecological footprint is defined here as "the area on the surface of Earth that each person appropriates in order to live," including many kinds of ecological services -- from food, air, water, and living space, to the recycling of wastes. This site offers an introduction to the concept of Ecological Footprints, including links to spreadsheets for calculation, national footprints, and related scientific articles.

  7. Ecological Inference

    NASA Astrophysics Data System (ADS)

    King, Gary; Rosen, Ori; Tanner, Martin A.

    2004-09-01

    This collection of essays brings together a diverse group of scholars to survey the latest strategies for solving ecological inference problems in various fields. The last half-decade has witnessed an explosion of research in ecological inference--the process of trying to infer individual behavior from aggregate data. Although uncertainties and information lost in aggregation make ecological inference one of the most problematic types of research to rely on, these inferences are required in many academic fields, as well as by legislatures and the Courts in redistricting, by business in marketing research, and by governments in policy analysis.

  8. Effective Management of Ocean Biogeochemistry and Ecological Data: the BCO-DMO Story

    NASA Astrophysics Data System (ADS)

    Chandler, C. L.; Groman, R. C.; Allison, M. D.; Wiebe, P. H.; Glover, D. M.; Gegg, S. R.

    2012-04-01

    Data availability expectations of the research community, environmental management decision makers, and funding agency representatives are changing. Consequently, data management practices in many science communities are changing as well. In an effort to improve access to data generated by ocean biogeochemistry and ecological researchers funded by the United States (US) National Science Foundation (NSF) Division of Ocean Sciences (OCE), the Biological and Chemical Oceanography Data Management Office (BCO-DMO) was created in late 2006. Currently, the main BCO-DMO objective is to ensure availability of data resulting from select OCE and Office of Polar Programs (OPP) research awards granted by the US NSF. An important requirement for the BCO-DMO data management system is that it provides open access to data that are supported by sufficient metadata to enable data discovery and accurate reuse. The office manages and serves all types of oceanographic data (in situ, experimental, model results) generated during the research process and contributed by the originating investigators from large national programs and medium-sized collaborative research projects, as well as researchers with single investigator awards. BCO-DMO staff members have made strategic use of standards and use of terms from controlled vocabularies while balancing the need to maintain flexible data ingest systems that accommodate the heterogeneous nature of ocean biogeochemistry and ecological research data. Many of the discrete ocean biogeochemistry data sets managed by BCO-DMO are still acquired manually, often with prototype sensor systems. Data sets such as these that are not "born-digital" present a significant management challenge. Use of multiple levels of term-mappings and development of an ontology has enabled BCO-DMO to incorporate a semantically enabled faceted search into the data access system that will improve data access through enhanced data discovery. BCO-DMO involves an ongoing collaboration between data managers and marine scientists funded by the US NSF. BCO-DMO staff members work with investigators throughout the data life cycle, beginning with the data management plan that is part of the original proposal, during cruise planning and experimental design, through data reporting to meet funding agency requirements and finally to submission of final data sets for publication and final archive in a permanent data center. It is important to note that support from and continued active involvement of the NSF program managers has been a significant contributor to the success of this developing system. URL: http://bco-dmo.org/

  9. Are large-scale manipulations of streamflow for ecological outcomes effective either as experiments or management actions? (Invited)

    NASA Astrophysics Data System (ADS)

    Konrad, C. P.; Olden, J.

    2013-12-01

    Dams impose a host of impacts on freshwater and estuary ecosystems. In recent decades, dam releases for ecological outcomes have been increasingly implemented to mitigate for these impacts and are gaining global scope. Many are designed and conducted using an experimental framework. A recent review of large-scale flow experiments (FE) evaluates their effectiveness and identifies ways to enhance their scientific and management value. At least 113 large-scale flow experiments affecting 98 river systems globally have been documented over the last 50 years. These experiments span a range of flow manipulations from single pulse events to comprehensive changes in flow regime across all seasons and different water year types. Clear articulation of experimental objectives, while not universally practiced, was crucial for achieving management outcomes and changing dam operating policies. We found a strong disparity between the recognized ecological importance of a multi faceted flow regimes and discrete flow events that characterized 80% of FEs. Over three quarters of FEs documented both abiotic and biotic outcomes, but only one third examined multiple trophic groups, thus limiting how this information informs future dam management. Large-scale flow experiments represent a unique opportunity for integrated biophysical investigations for advancing ecosystem science. Nonetheless, they must remain responsive to site-specific issues regarding water management, evolving societal values and changing environmental conditions and, in particular, can characterize the incremental benefits from and necessary conditions for changing dam operations to improve ecological outcomes. This type of information is essential for understanding the full context of value based trade-offs in benefits and costs from different dam operations that can serve as an empirical basis for societal decisions regarding water and ecosystem management. FE may be the best approach available to managers for resolving critical uncertainties that impede decision making in adaptive settings, for example, when we lack sufficient understanding to model biophysical responses to alternative operations. Integrated long term monitoring of biotic abiotic responses and defining clear management based objectives highlight ways for improving the efficiency and value of FEs.

  10. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    SciTech Connect

    Tuskan, Gerald A [ORNL; Yin, Tongming [ORNL

    2008-10-01

    Lack of aspen (Populus tremuloides) recruitment and canopy replacement of aspen stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado has been a cause of concern for more than 70 years (Packard, 1942; Olmsted, 1979; Stevens, 1980; Hess, 1993; R.J. Monello, T.L. Johnson, and R.G. Wright, Rocky Mountain National Park, 2006, written commun.). These aspen stands are a significant resource since they are located close to the park's road system and thus are highly visible to park visitors. Aspen communities are integral to the ecological structure of montane and subalpine landscapes because they contain high native species richness of plants, birds, and butterflies (Chong and others, 2001; Simonson and others, 2001; Chong and Stohlgren, 2007). These low-elevation, winter range stands also represent a unique component of the park's plant community diversity since most (more than 95 percent) of the park's aspen stands grow in coniferous forest, often on sheltered slopes and at higher elevations, while these winter range stands are situated on the low-elevation ecotone between the winter range grasslands and some of the park's drier coniferous forests.

  11. Effects of wind energy development on nesting ecology of greater prairie-chickens in fragmented grasslands.

    PubMed

    McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

    2014-08-01

    Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before-after control-impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (? = 0.03, 95% CI = -1.2-1.3) or nest survival (? = -0.3, 95% CI = -0.6-0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. PMID:24628394

  12. Conservation Ecology

    NSDL National Science Digital Library

    1997-01-01

    Conservation Ecology is a new, exclusively electronic, peer-reviewed scientific journal of the Resilience Alliance, with content ranging from the applied to the theoretical. Topics covered by the journal include: "the conservation of ecosystems, landscapes, species, populations, and genetic diversity; the restoration of ecosystems and habitats; and the management of resources." This site includes the full text version of the articles (including past issues), as well as instructions on how to submit papers and how to subscribe. Subscriptions to Conservation Ecology are free of charge and all materials are available for browsing without cost. Edited by ecosystem ecology expert, Dr. C. S. Holling, Conservation Ecology breaks new ground in an important, emerging science.

  13. Urban Ecology

    NSDL National Science Digital Library

    When people think about the concept and idea of ecology, they may not immediately picture a bustling urban street or a network of interconnected bike paths. Since 1975, a group of architects and activists have been thinking about exactly those things in terms of urban ecology (and a good deal more to boot), coupling it with a conviction that urban ecology can draw on ecology, public participation and urban planning "to help design and build healthier cities." Given these ideas, it seems logical that this organization has its roots in the Bay Area, and continues to offer up interesting plans and proposals, many of which can be found on the website. One such document is the Walkable Streets Toolkit, which is designed for use by communities that seek to make their streets more pedestrian friendly. Additionally, visitors will want to look at current and past editions of The Urban Ecologist, which is the group's quarterly newsletter.

  14. Phytoplankton Ecology

    NSDL National Science Digital Library

    This site describes phytoplankton ecology research by marine ecologists at Mote Marine Laboratory (MML), an independent, nonprofit research organization based in Sarasota, Florida. The emphasis of MML's phytoplankton ecology research is the photophysiology of marine algae -- with recent emphasis on the ability to predict and possibly mitigate blooms of the toxic marine dinoflagellate, Gymnodinium breve. The no-frills phytoplankton ecology homepage describes research and offers data (maps, figures, tables) from 1998 and 1999 projects on Red Tide transects, Nutrient and chlorophyll concentrations, and Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) transect data, among several others. The site also offers general information on Red Tides, Red Tide conditions in Southwest Florida, a chronology of historic Red Tide events, and links to related resources.

  15. Identifying reefs of hope and hopeful actions: contextualizing environmental, ecological, and social parameters to respond effectively to climate change.

    PubMed

    McClanahan, T R; Cinner, J E; Graham, N A J; Daw, T M; Maina, J; Stead, S M; Wamukota, A; Brown, K; Venus, V; Polunin, N V C

    2009-06-01

    Priorities for conservation, management, and associated activities will differ based on the interplay between nearness of ecosystems to full recovery from a disturbance (pristineness), susceptibility to climate change (environmental susceptibility [ES]), and capacity of human communities to cope with and adapt to change (social adaptive capacity [AC]). We studied 24 human communities and adjacent coral reef ecosystems in 5 countries of the southwestern Indian Ocean. We used ecological measures of abundance and diversity of fishes and corals, estimated reef pristineness, and conducted socioeconomic household surveys to determine the AC of communities adjacent to selected coral reefs. We also used Web-based oceanographic and coral mortality data to predict each site's ES to climate warming. Coral reefs of Mauritius and eastern Madagascar had low ES and consequently were not predicted to be affected strongly by warm water, although these sites were differentiated by the AC of the human community. The higher AC in Mauritius may increase the chances for successful self-initiated recovery and protective management of reefs of this island. In contrast, Madagascar may require donor support to build AC as a prerequisite to preservation efforts. The Seychelles and Kenya had high ES, but their levels of AC and disturbance differed. The high AC in the Seychelles could be used to develop alternatives to dependence on coral reef resources and reduce the effects of climate change. Pristineness weighted toward measures of fish recovery was greatest for Kenya's marine protected areas; however, most protected areas in the region were far from pristine. Conservation priorities and actions with realistic chances for success require knowledge of where socioecological systems lie among the 3 axes of environment, ecology, and society. PMID:19245493

  16. Campus Ecology

    NSDL National Science Digital Library

    National Wildlife Federation

    This website from the National Wildlife Federation showcases environmental conservation projects that have been successfully undertaken by various universities. The site features example projects and resources for doing your own campus project. Topics include building design, energy, environmental literacy, habitat restoration, water, transportation and waste reduction. Links to the online Campus Ecology Yearbook and the Campus Ecology Research Station and other resources are also included.

  17. Warfare Ecology

    Microsoft Academic Search

    Gary E. Machlis; Thor Hanson

    \\u000a Among human activities causing ecological change, war is both intensive and far-reaching. Yet environmental research related\\u000a to warfare is limited in depth and fragmented by discipline. Here we (1) outline a field of study called “warfare ecology,”\\u000a (2) provide a taxonomy of warfare useful for organizing the field, (3) review empirical studies, and (4) propose research\\u000a directions and policy implications

  18. ASSSOCIATION BETWEEN LOCI WITH DELETERIOUS ALLELES AND DISTORTED SEX RATIOS IN AN INBRED LINE OF TILAPIA (OREOCHOMIS AUREUS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three microsatellite markers (UNH159, UNH231, and UNH216) were examined for association with both deleterious genes and sex ratio distortions in a full-sib family of 222 progeny from the fourth generation of a meiogynogenetic tilapia line (Oreochromis aureus). The three markers previously were mappe...

  19. Common sex-linked deleterious alleles in a plant parasitic fungus alter infection success but show no pleiotropic advantage

    Microsoft Academic Search

    T. GIRAUD; O. JONOT; J. A. SHYKOFF

    2005-01-01

    Microbotryum violaceum is a fungus that causes the sterilizing anther smut disease in Caryophyllaceae. Its diploid teliospores normally produce equal proportions of haploid sporidia of its two mating types. However natural populations contain high frequencies of individuals producing sporidia of only one mating type ('biased strains'). This mating type-ratio bias is caused by deleterious alleles at haploid phase ('haplo-lethals') linked

  20. The Ecological Impact of Biofuels

    E-print Network

    Kammen, Daniel M.

    The Ecological Impact of Biofuels Joseph E. Fargione,1 Richard J. Plevin,2 and Jason D. Hill3 1 land-use change Abstract The ecological impact of biofuels is mediated through their effects on land, air, and water. In 2008, about 33.3 million ha were used to produce food- based biofuels

  1. Journal of Animal Ecology 2004

    E-print Network

    Engen, Steinar

    Journal of Animal Ecology 2004 73, 925­934 © 2004 British Ecological Society Time to extinction Curie, Bat. A, 177, quai St Bernard, Case 237, F-75252 Paris Cedex 5, France; ¶Department of Animal consider the effects on the estimated time to extinction and whether density regulation acts only

  2. Ecological Engineering in Water Resources

    Microsoft Academic Search

    Kirk R. Barrett

    1999-01-01

    Ecological engineering is a relatively unfamiliar; cost-effective strategy for tackling the “second generation” of water resource problems. It can be defined as the design, construction, operation, and management of landscape\\/aquatic structures and associated plant and animal communities to benefit humanity and nature. It is introduced by comparing it with “conventional” engineering, including case studies with cost and performance data. Ecological

  3. Chemical Modulation of Mutant mGlu1 Receptors Derived from Deleterious GRM1 Mutations Found in Schizophrenics

    PubMed Central

    2014-01-01

    Schizophrenia is a complex and highly heterogeneous psychiatric disorder whose precise etiology remains elusive. While genome-wide association studies (GWAS) have identified risk genes, they have failed to determine if rare coding single nucleotide polymorphisms (nsSNPs) contribute in schizophrenia. Recently, two independent studies identified 12 rare, deleterious nsSNPS in the GRM1 gene, which encodes the metabotropic glutamate receptor subtype 1 (mGlu1), in schizophrenic patients. Here, we generated stable cell lines expressing the mGlu1 mutant receptors and assessed their pharmacology. Using both the endogenous agonist glutamate and the synthetic agonist DHPG, we found that several of the mutant mGlu1 receptors displayed a loss of function that was not due to a loss in plasma membrane expression. Due to a lack of mGlu1 positive allosteric modulators (PAM) tool compounds active at human mGlu1, we optimized a known mGlu4 PAM/mGlu1 NAM chemotype into a series of potent and selective mGlu1 PAMs by virtue of a double “molecular switch”. Employing mGlu1 PAMs from multiple chemotypes, we demonstrate that the mutant receptors can be potentiated by small molecules and in some cases efficacy restored to that comparable to wild type mGlu1 receptors, suggesting deficits in patients with schizophrenia due to these mutations may be amenable to intervention with an mGlu1 PAM. However, in wild type animals, mGlu1 negative allosteric modulators (NAMs) are efficacious in classic models predictive of antipsychotic activity, whereas we show that mGlu1 PAMs have no effect to slight potentiation in these models. These data further highlight the heterogeneity of schizophrenia and the critical role of patient selection strategies in psychiatric clinical trials to match genotype with therapeutic mechanism. PMID:25137254

  4. Compliance to a Cell Phone-Based Ecological Momentary Assessment Study: The Effect of Time and Personality Characteristics

    ERIC Educational Resources Information Center

    Courvoisier, Delphine S.; Eid, Michael; Lischetzke, Tanja

    2012-01-01

    Ecological momentary assessment (EMA) is a method that is now widely used to study behavior and mood in the settings in which they naturally occur. It maximizes ecological validity and avoids the limitations of retrospective self-reports. Compliance patterns across time have not been studied. Consistent compliance patterns could lead to data not…

  5. Ontogenetic patterns in bluefish (Pomatomus saltatrix) feeding ecology and the effect on mercury biomagnification.

    PubMed

    Szczebak, Joseph T; Taylor, David L

    2011-06-01

    In this study, bluefish (Pomatomus saltatrix; age 0-7, n?=?632) and their prey (forage fish, macroinvertebrates, zooplankton; n?=?2,005) were collected from the Narragansett Bay estuary (RI, USA), and total Hg concentration was measured in white muscle and whole-body tissues, respectively. Bluefish Hg concentrations were analyzed relative to fish length, prey Hg content, and ontogenetic shifts in habitat use and foraging ecology, the latter assessed using stomach content analysis (n?=?711) and stable nitrogen (?(15)N) and carbon (?(13)C) isotope measurements (n?=?360). Diet and ?(13)C analysis showed that age 0 bluefish consumed both benthic and pelagic prey (silversides, sand shrimp, planktonic crustaceans; ?(13)C?=?-?16.52‰), whereas age 1?+ bluefish fed almost exclusively on pelagic forage fish (Atlantic menhaden, herring; ?(13)C?=?-?17.33‰). Bluefish total Hg concentrations were significantly correlated with length (mean Hg?=?0.041 and 0.254?ppm wet wt for age 0 and age 1?+ bluefish, respectively). Furthermore, Hg biomagnification rates were maximal during bluefish early life stages and decelerated over time, resulting in relatively high Hg concentrations in age 0 fish. Rapid Hg accumulation in age 0 bluefish is attributed to these individuals occupying a comparable trophic level to age 1?+ bluefish (?(15)N?=?15.58 and 16.09‰; trophic level?=?3.55 and 3.71 for age 0 and age 1?+ bluefish, respectively), as well as juveniles having greater standardized consumption rates of Hg-contaminated prey. Finally, bluefish larger than 30?cm total length consistently had Hg levels above the U.S. Environmental Protection Agency criterion of 0.3?ppm. As such, frequent consumption of bluefish could pose a human health risk, and preferentially consuming smaller bluefish may be an inadequate strategy for minimizing human dietary exposure to Hg. PMID:21381087

  6. An association-adjusted consensus deleterious scheme to classify homozygous Mis-sense mutations for personal genome interpretation

    PubMed Central

    2013-01-01

    Background Personal genome analysis is now being considered for evaluation of disease risk in healthy individuals, utilizing both rare and common variants. Multiple scores have been developed to predict the deleteriousness of amino acid substitutions, using information on the allele frequencies, level of evolutionary conservation, and averaged structural evidence. However, agreement among these scores is limited and they likely over-estimate the fraction of the genome that is deleterious. Method This study proposes an integrative approach to identify a subset of homozygous non-synonymous single nucleotide polymorphisms (nsSNPs). An 8-level classification scheme is constructed from the presence/absence of deleterious predictions combined with evidence of association with disease or complex traits. Detailed literature searches and structural validations are then performed for a subset of homozygous 826 mis-sense mutations in 575 proteins found in the genomes of 12 healthy adults. Results Implementation of the Association-Adjusted Consensus Deleterious Scheme (AACDS) classifies 11% of all predicted highly deleterious homozygous variants as most likely to influence disease risk. The number of such variants per genome ranges from 0 to 8 with no significant difference between African and Caucasian Americans. Detailed analysis of mutations affecting the APOE, MTMR2, THSB1, CHIA, ?MyHC, and AMY2A proteins shows how the protein structure is likely to be disrupted, even though the associated phenotypes have not been documented in the corresponding individuals. Conclusions The classification system for homozygous nsSNPs provides an opportunity to systematically rank nsSNPs based on suggestive evidence from annotations and sequence-based predictions. The ranking scheme, in-depth literature searches, and structural validations of highly prioritized mis-sense mutations compliment traditional sequence-based approaches and should have particular utility for the development of individualized health profiles. An online tool reporting the AACDS score for any variant is provided at the authors’ website. PMID:24365473

  7. Discriminating between deleterious and neutral non-frameshifting indels based on protein interaction networks and hybrid properties.

    PubMed

    Zhang, Ning; Huang, Tao; Cai, Yu-Dong

    2015-02-01

    More than ten thousand coding variants are contained in each human genome; however, our knowledge of the way genetic variants underlie phenotypic differences is far from complete. Small insertions and deletions (indels) are one of the most common types of human genetic variants, and indels play a significant role in human inherited disease. To date, we still lack a comprehensive understanding of how indels cause diseases. Therefore, identification and analysis of such deleterious variants is a key challenge and has been of great interest in the current research in genome biology. Increasing numbers of computational methods have been developed for discriminating between deleterious indels and neutral indels. However, most of the existing methods are based on traditional sequential or structural features, which cannot completely explain the association between indels and the resulting induced inherited disease. In this study, we establish a novel method to predict deleterious non-frameshifting indels based on features extracted from both protein interaction networks and traditional hybrid properties. Each indel was coded by 1,246 features. Using the maximum relevance minimum redundancy method and the incremental feature selection method, we obtained an optimal feature set containing 42 features, of which 21 features were derived from protein interaction networks. Based on the optimal feature set, an 88 % accuracy and a 0.76 MCC value were achieved by a Random Forest as evaluated by the Jackknife cross-validation test. This method outperformed existing methods of predicting deleterious indels, and can be applied in practice for deleterious non-frameshifting indel predictions in genome research. The analysis of the optimal features selected in the model revealed that network interactions play more important roles and could be informative for better illustrating an indel's function and disease associations than traditional sequential or structural features. These results could shed some light on the genetic basis of human genetic variations and human inherited diseases. PMID:25248637

  8. Protecting exons from deleterious R-loops: a potential advantage of having introns

    PubMed Central

    Niu, Deng-Ke

    2007-01-01

    Background Accumulating evidence indicates that the nascent RNA can invade and pair with one strand of DNA, forming an R-loop structure that threatens the stability of the genome. In addition, the cost and benefit of introns are still in debate. Results At least three factors are likely required for the R-loop formation: 1) sequence complementarity between the nascent RNA and the target DNA, 2) spatial juxtaposition between the nascent RNA and the template DNA, and 3) accessibility of the template DNA and the nascent RNA. The removal of introns from pre-mRNA reduces the complementarity between RNA and the template DNA and avoids the spatial juxtaposition between the nascent RNA and the template DNA. In addition, the secondary structures of group I and group II introns may act as spatial obstacles for the formation of R-loops between nearby exons and the genomic DNA. Conclusion Organisms may benefit from introns by avoiding deleterious R-loops. The potential contribution of this benefit in driving intron evolution is discussed. I propose that additional RNA polymerases may inhibit R-loop formation between preceding nascent RNA and the template DNA. This idea leads to a testable prediction: intermittently transcribed genes and genes with frequently prolonged transcription should have higher intron density. Reviewers This article was reviewed by Dr. Eugene V. Koonin, Dr. Alexei Fedorov (nominated by Dr. Laura F Landweber), and Dr. Scott W. Roy (nominated by Dr. Arcady Mushegian). PMID:17459149

  9. Selective propagation of functional mitochondrial DNA during oogenesis restricts the transmission of a deleterious mitochondrial variant.

    PubMed

    Hill, Jahda H; Chen, Zhe; Xu, Hong

    2014-04-01

    Although mitochondrial DNA (mtDNA) is prone to mutation and few mtDNA repair mechanisms exist, crippling mitochondrial mutations are exceedingly rare. Recent studies have demonstrated strong purifying selection in the mouse female germline. However, the mechanisms underlying positive selection of healthy mitochondria remain to be elucidated. We visualized mtDNA replication during Drosophila melanogaster oogenesis, finding that mtDNA replication commenced before oocyte determination during the late germarium stage and was dependent on mitochondrial fitness. We isolated a temperature-sensitive lethal mtDNA allele, mt:CoI(T300I), which resulted in reduced mtDNA replication in the germarium at the restrictive temperature. Additionally, the frequency of the mt:CoI(T300I) allele in heteroplasmic flies was decreased, both during oogenesis and over multiple generations, at the restrictive temperature. Furthermore, we determined that selection against mt:CoI(T300I) overlaps with the timing of selective replication of mtDNA in the germarium. These findings establish a previously uncharacterized developmental mechanism for the selective amplification of wild-type mtDNA, which may be evolutionarily conserved to limit the transmission of deleterious mutations. PMID:24614072

  10. Partition dataset according to amino acid type improves the prediction of deleterious non-synonymous SNPs

    SciTech Connect

    Yang, Jing; Li, Yuan-Yuan [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China) [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China); Shanghai Center for Bioinformation Technology, Shanghai 200235 (China); Li, Yi-Xue, E-mail: yxli@sibs.ac.cn [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China) [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China); Shanghai Center for Bioinformation Technology, Shanghai 200235 (China); Ye, Zhi-Qiang, E-mail: yezq@pkusz.edu.cn [Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055 (China) [Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055 (China); Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031 (China)

    2012-03-02

    Highlights: Black-Right-Pointing-Pointer Proper dataset partition can improve the prediction of deleterious nsSNPs. Black-Right-Pointing-Pointer Partition according to original residue type at nsSNP is a good criterion. Black-Right-Pointing-Pointer Similar strategy is supposed promising in other machine learning problems. -- Abstract: Many non-synonymous SNPs (nsSNPs) are associated with diseases, and numerous machine learning methods have been applied to train classifiers for sorting disease-associated nsSNPs from neutral ones. The continuously accumulated nsSNP data allows us to further explore better prediction approaches. In this work, we partitioned the training data into 20 subsets according to either original or substituted amino acid type at the nsSNP site. Using support vector machine (SVM), training classification models on each subset resulted in an overall accuracy of 76.3% or 74.9% depending on the two different partition criteria, while training on the whole dataset obtained an accuracy of only 72.6%. Moreover, the dataset was also randomly divided into 20 subsets, but the corresponding accuracy was only 73.2%. Our results demonstrated that partitioning the whole training dataset into subsets properly, i.e., according to the residue type at the nsSNP site, will improve the performance of the trained classifiers significantly, which should be valuable in developing better tools for predicting the disease-association of nsSNPs.

  11. Mercury: Aspects of its ecology and environmental toxicity. [physiological effects of mercury compound contamination of environment

    NASA Technical Reports Server (NTRS)

    Siegel, S. M.

    1973-01-01

    A study was conducted to determine the effects of mercury pollution on the environment. The possible sources of mercury contamination in sea water are identified. The effects of mercury on food sources, as represented by swordfish, are analyzed. The physiological effects of varying concentrations of mercury are reported. Emphasis is placed on the situation existing in the Hawaiian Islands.

  12. Stimulatory effects of tannins and cholic acid on tryptic hydrolysis of proteins: Ecological implications

    Microsoft Academic Search

    Simon Mole; Peter G. Waterman

    1985-01-01

    The biochemical basis for considering tannins as digestion inhibitors has been reexamined. Both stimulatory and inhibitory effects of tannins on tryptic hydrolysis are reported. We show how stimulation may result from tannin-induced structural changes in the substrate protein, effectively denaturing it. The surfactant and bile constituent cholic acid also produced similar stimulatory effects. These results have considerable implications for normal

  13. Review article. Studying climate effects on ecology through the use of climate indices: the North Atlantic Oscillation, El Niño Southern Oscillation and beyond.

    PubMed Central

    Stenseth, Nils Chr; Ottersen, Geir; Hurrell, James W; Mysterud, Atle; Lima, Mauricio; Chan, Kung-Sik; Yoccoz, Nigel G; Adlandsvik, Bjørn

    2003-01-01

    Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet. PMID:14561270

  14. June 26, 2006 Ecology and Political Upheaval

    E-print Network

    June 26, 2006 Ecology and Political Upheaval Small changes in climate can cause wars, topple always discussed in political and military terms, has roots in an ecological crisis directly arising from supplies. Public debates tend to neglect powerful ecological effects because we focus on politics

  15. Hydrothermal carbonization of biomass residues: mass spectrometric characterization for ecological effects in the soil-plant system.

    PubMed

    Jandl, Gerald; Eckhardt, Kai-Uwe; Bargmann, Inge; Kücke, Martin; Greef, Jörg-Michael; Knicker, Heike; Leinweber, Peter

    2013-01-01

    Hydrochars, technically manufactured by hydrothermal carbonization (HTC) of biomass residues, are recently tested in high numbers for their suitability as feedstock for bioenergy production, the bioproduct industry, and as long-term carbon storage in soil, but ecological effects in the soil-plant system are not sufficiently known. Therefore, we investigated the influence of different biomass residues and process duration on the molecular composition of hydrochars, and how hydrochar addition to soils affected the germination of spring barley ( L.) seeds. Samples from biomass residues and the corresponding hydrochars were analyzed by pyrolysis-field ionization mass spectrometry (Py-FIMS) and gaseous emissions from the germination experiments with different soil-hydrochar mixtures by gas chromatography/mass spectrometry (GC/MS). The molecular-level characterization of various hydrochars by Py-FIMS clearly showed that the kind of biomass residue influenced the chemical composition of the corresponding hydrochars more strongly than the process duration. In addition to various detected possible toxic substances, two independent mass spectrometric methods (Py-FIMS and GC/MS) indicated long C-chain aliphatic compounds which are typically degraded to the C-unit ethylene that can evoke phytotoxic effects in high concentrations. This showed for the first time possible chemical compounds to explain toxic effects of hydrochars on plant growth. It is concluded that the HTC process did not result in a consistent product with defined chemical composition. Furthermore, possible toxic effects urgently need to be investigated for each individual hydrochar to assess effects on the soil organic matter composition and the soil biota before hydrochar applications as an amendment on agricultural soils. PMID:23673755

  16. Geographical Distribution of Adolescent Body Height with Respect to Effective Day Length in Japan: An Ecological Analysis

    PubMed Central

    Yokoya, Masana; Shimizu, Hideyasu; Higuchi, Yukito

    2012-01-01

    The height of Japanese youth raised in the northern region tends to be greater than that of youth raised in the southern region; therefore, a geographical gradient in youth body height exists. Although this gradient has existed for about 100 years, the reasons for it remain unclear. Consideration of the nutritional improvement, economic growth, and intense migration that has occurred in this period indicates that it is probably the result of environmental rather than nutritional or genetic factors. To identify possible environmental factors, ecological analysis of prefecture-level data on the body size of 8- to 17-year-old youth averaged over a 13-year period (1996 to 2008) and Japanese mesh climatic data on the climatic variables of temperature, solar radiation, and effective day length (duration of photoperiod exceeding the threshold of light intensity) was performed. The geographical distribution of the standardized height of Japanese adolescents was found to be inversely correlated to a great extent with the distribution of effective day length at a light intensity greater than 4000 lx. The results of multiple regression analysis of effective day length, temperature, and weight (as an index of food intake) indicated that a combination of effective day length and weight was statistically significant as predictors of height in early adolescence; however, only effective day length was statistically significant as a predictor of height in late adolescence. Day length may affect height by affecting the secretion of melatonin, a hormone that inhibits sexual and skeletal maturation, which in turn induces increases in height. By affecting melatonin production, regional differences in the duration of the photoperiod may lead to regional differences in height. Exposure to light intensity greater than 4000 lx appears to be the threshold at which light intensity begins to affect the melatonin secretion of humans who spend much of their time indoors. PMID:23227226

  17. Investigations on the Effects of Dietary Essential Oils and Different Husbandry Conditions on the Gut Ecology in Piglets after Weaning

    PubMed Central

    Janczyk, P.; Pieper, R.; Urubschurov, V.; Wendler, K. R.; Souffrant, W. B.

    2009-01-01

    Essential oils (EO) are being considered as possible alternatives to in-feed antibiotic growth promoters in pig nutrition. The effects of an EO mixture consisting of limonene, eugenol and pinene (10.0, 2.0, and 4.8 mg/kg diet, resp.) on gut physiology and ecology were studied in piglets. The experiment was conducted at low (commercial farm) and high hygienic conditions (experimental farm), to elucidate interactions between EO supplementation and husbandry methods. Piglets were weaned at 28 days of age, when they were offered either a control diet (C) or C with EO. Four piglets were sacrificed in each group on day 29, 30, 33 and 39. Digesta from the third distal part of the small intestine and from the colon were sampled and analysed for pH, dry matter, lactic acid, short chain fatty acids and ammonia concentrations. Enterobacteria, enterococci, lactobacilli and yeast counts were obtained by plating. Genomic DNA was extracted from digesta and polymerase chain reaction—denaturing gradient gel electrophoresis was performed. Individual microbial communities were identified at each farm. Age affected the intestinal parameters. No effects of the EO with exception for a significant reduction in colon bacterial diversity at 39 days of age could be recorded at experimental farm. PMID:20016670

  18. Ecological risk assessment in a large river-reservoir. 7: Environmental contaminant accumulation and effects in great blue heron

    SciTech Connect

    Halbrook, R.S. [Southern Illinois Univ., Carbondale, IL (United States); Brewer, R.L. Jr.; Buehler, D.A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Forestry, Wildlife and Fisheries

    1999-04-01

    Past plant operations and waste disposal on the Oak Ridge Reservation (ORR) have introduced an assortment of potentially harmful contaminants into the surrounding environment. Elevated concentrations of mercury (Hg) and PCBs have been found in fish collected from aquatic systems on the ORR, and a screening level risk assessment has identified piscivorous wildlife downstream from the ORR as being at risk. As a component of an ecological risk assessment of a large river-reservoir system, the great blue heron (Ardea herodias) was chosen as an endpoint species to evaluate potential adverse effects of contaminants on piscivorous wildlife using aquatic systems on or downstream of the ORR. Eggs and chick liver, muscle, and fat samples were collected from two heron colonies located on and two colonies located off the ORR. Samples were analyzed for PCBs, mercury, chromium, and arsenic to determine if differences existed among colonies. Mean mercury and PCB concentrations were greater in eggs and chick tissues collected from colonies located on the ORR. However, no biologically significant differences were observed in fecundity or in egg physical measurements or chick physiological measurements between study locations. The results of this study do not indicate that the contaminant burdens in great blue heron chicks and eggs have a detrimental effect on heron populations utilizing aquatic habitats on the ORR.

  19. Towards a synthesis of frameworks in nutritional ecology: interacting effects of protein, carbohydrate and phosphorus on field cricket fitness.

    PubMed

    Harrison, Sarah J; Raubenheimer, David; Simpson, Stephen J; Godin, Jean-Guy J; Bertram, Susan M

    2014-10-01

    Phosphorus has been identified as an important determinant of nutrition-related biological variation. The macronutrients protein (P) and carbohydrates (C), both alone and interactively, are known to affect animal performance. No study, however, has investigated the importance of phosphorus relative to dietary protein or carbohydrates, or the interactive effects of phosphorus with these macronutrients, on fitness-related traits in animals. We used a nutritional geometry framework to address this question in adult field crickets (Gryllus veletis). Our results showed that lifespan, weight gain, acoustic mate signalling and egg production were maximized on diets with different P : C ratios, that phosphorus did not positively affect any of these fitness traits, and that males and females had different optimal macronutrient intake ratios for reproductive performance. When given a choice, crickets selected diets that maximized both lifespan and reproductive performance by preferentially eating diets with low P : C ratios, and females selected diets with a higher P : C ratio than males. Conversely, phosphorus intake was not regulated. Overall, our findings highlight the importance of disentangling the influences of different nutrients, and of quantifying both their individual and interactive effects, on animal fitness traits, so as to gain a more integrative understanding of their nutritional ecology. PMID:25143029

  20. Designing for ecology : the ecological park

    E-print Network

    Power, Andres M

    2006-01-01

    This thesis aims to define a) what an ecological park is, and b) whether it is a new model in park design. Reference to the literature on landscape ecology is used to analyze the natural ecological merit of these parks, ...

  1. Ecological effects of feral biofuel crops in constructed oak savannah communities - June 2012

    EPA Science Inventory

    The effects of elevated temperatures and drought on constructed oak savannahs were studied to determine the interactive effects of potentially invasive feral biofuel species and climate change on native grassland communities. A total of 12 sunlit mesocosm were used. Each mesoco...

  2. Identifying Hazards in Complex Ecological Systems. Part 2: Infection Modes and Effects Analysis for Biological Invasions

    Microsoft Academic Search

    Keith R. Hayes

    2002-01-01

    This paper describes a rigorous and systematic hazard analysis, called infection modes and effects analysis (named after its industrial counterpart failure modes and effect analysis (FMEA)), which was used to investigate the potential spread of marine organisms by human vectors. The analysis was conducted using small craft as a model system and implemented through nine workshops targeted at owners and

  3. Ecological heterogeneity and the evaluation of the effects of marine reserves

    Microsoft Academic Search

    Jose Antonio Garc??a Charton; Ángel Pérez Ruzafa

    1999-01-01

    In recent decades marine reserves have been established throughout the world as a management tool for compensating the effects of overfishing on coastal marine stocks. Despite the growing literature about the expected response of populations and communities to protection from fisheries, and the number of studies measuring some of these effects, most of the mechanisms supposed to work in a

  4. Effects on the ecological integrity of a soft-bottom habitat from a trawling disturbance

    Microsoft Academic Search

    Pamela J. Sparks-McConkey; Les Watling

    2001-01-01

    The effects of trawling disturbance on a soft-sediment system were investigated with a manipulative field experiment in an area that had been closed to shrimp trawling activities for 20 years. The area was also chosen for its weak natural physical agents i.e. no scouring of sediments by storm events or tidal flow, allowing a quantitative assessment of the effects of

  5. ECOLOGICAL EFFECTS OF COMBINED ORGANIC OR INORGANIC POLLUTION ON SOIL MICROBIAL ACTIVITIES

    Microsoft Academic Search

    PING GONG; TIE-HENG SUN; GÜNTER BEUDERT; HERMANN H. HAHN

    1997-01-01

    Combined effects of organic or inorganic pollutants on soil microbial activities were investigated in field plots grown with four types of covering plants. It was derived from this study that combined effects were dependent not only on the type and dose of pollutants, addition of soda lime, plant type and season variation, but also on test parameters. When jointly added,

  6. Ecological Modelling 152 (2002) 205211 The effectiveness of various rabies spatial vaccination

    E-print Network

    Bohrer, Gil

    whether a non-uniform spread of oral rabies vaccination could be more effective in eradicating the disease densities vary over space, non-uniform spreading of oral rabies vaccination may, under certain circumstances. Introduction Oral rabies vaccination (ORV) is currently con- sidered the most effective method of curtailing

  7. Ecological resistance to the invasion of a freshwater clam, Corbicula fluminea : fish predation effects

    Microsoft Academic Search

    James V. Robinson; Gary A. Wellborn

    1988-01-01

    Fish predation is shown to have a twenty nine fold effect on the abundance of the invasive freshwater clam, Corbicula fluminea, in a Texas reservoir. This predation has prevented the clam from establishing the high densities commonly reported for it elsewhere. The high magnitude of the fish effect is attributed to Corbicula being an invader to this reservoir and not

  8. Review: Bucephalus minimus, a deleterious trematode parasite of cockles Cerastoderma spp.

    PubMed

    Magalhães, L; Freitas, R; de Montaudouin, X

    2015-04-01

    Trematodes are the most prevalent and abundant macroparasites in coastal waters. They display a complex life cycle with alternation of free-living and parasitic stages generally involving three host species. The most deleterious stage is in the first intermediate host (a mollusc) where the parasite penetrates as miracidium larvae and asexually multiplicates in sporocysts/rediae to provide cercariae larvae. However, due to basic low prevalence in ecosystems, this system remains difficult to study. Taking the example of the cockle (Cerastoderma edule), an exploited bivalve along North-Eastern Atlantic coasts, and Bucephalus minimus, its most prevalent parasite as first intermediate host, we summarised the 51 most relevant papers (1887-2015). Besides, a 16-year monthly monitoring was performed at Banc d'Arguin (Atlantic coast of France), and allowed to obtain a sufficient number of infected cockles (276 out of 5,420 individuals) in order to provide new information concerning this parasite/host system. Sporocysts (diameter 80-500 ?m) and developing cercariae (length 300-500 ?m) are not visible before cockle reaches 16-mm shell length and then prevalence increases with host size. Seasonality of infection was not observed but variation of prevalence was significant among years and negatively correlated to the temperature of the former year, which could correspond to the period of infection by miracidium. Seven other species of trematode were identified in cockles as second intermediate host. For six of them, metacercariae abundance per individual was 2 to 12 folds higher in B. minimus-infected cockles, exacerbating the potential negative impact on host. From the parasite point of view, metacercariae can be considered as hitchhikers, taking advantage of the abnormal migration of B. minimus-infected cockles to the sediment surface where they become more vulnerable to predators that are also the final hosts of many of these parasites. PMID:25681142

  9. Effects of Wind Energy Development on Nesting Ecology of Greater Prairie-Chickens in Fragmented Grasslands

    PubMed Central

    McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

    2014-01-01

    Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before–after control–impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (? = 0.03, 95% CI = ?1.2–1.3) or nest survival (? = ?0.3, 95% CI = ?0.6–0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. Efectos del Desarrollo de la Energía Eólica sobre la Ecología de Anidación de Gallinas de la Gran Pradera en Pastizales Fragmentados Resumen Se calcula que la energía eólica aportará el 20% de las necesidades energéticas de los Estados Unidos para el 2030, pero nuevos sitios para el desarrollo de energía renovable pueden traslaparse con hábitats importantes de poblaciones declinantes de aves de pastizal. La gallina de la Gran Pradera (Tympanuchus cupido) es una especie de ave obligada de pastizal que se pronostica responderá negativamente al desarrollo energético. Usamos un diseño ADCI modificado para probar los impactos del desarrollo de la energía eólica sobre la ecología reproductiva de las gallinas en un estudio de 5 años. Ubicamos 59 y 185 nidos antes y después del desarrollo, respectivamente, de una instalación de energía eólica de 201 MW en el hábitat de anidación de las gallinas y estudiamos la selección de sitio de anidación y la supervivencia de nidos en relación con la proximidad a la infraestructura y las condiciones de hábitat. La proximidad con las turbinas no afectó negativamente a la selección de sitios de anidación (? = -0.3, 95% CI = -0.6–0.1). En su lugar, la selección de sitios de anidación y la supervivencia estuvieron fuertemente relacionadas con la cobertura vegetal y otras condiciones locales determinadas por el manejo de la producción de ganado. La integración de los resultados de nuestro proyecto con reportes previos de la evitación conductual de instalaciones de petróleo y gas por otras especies de pastizales sugiere nuevas vías para que la investigación mitigue los impactos del desarrollo energético. PMID:24628394

  10. COMMUNITY ECOLOGY -ORIGINAL RESEARCH Direct versus indirect effects of habitat fragmentation

    E-print Network

    With, Kimberly A.

    richness than interior cells. Frag- mentation per se did not have a direct effect on local-scale diversity patches. Thus, although frag- mentation typically entails habitat loss, habitat loss can occur in ways

  11. Hydrologic and Ecological Effects of Watershed Urbanization: Implication for Watershed Management in Hillslope Regions

    E-print Network

    Sung, Chan Yong

    2011-08-08

    In this study, I examined the effect of watershed urbanization on the invasion of alien woody species in riparian forests. This study was conducted in three major steps: 1) estimating the degree of watershed urbanization using impervious surface...

  12. GROUP REPORT: PHYSIOLOGICAL AND ECOLOGICAL EFFECTS OF ACIDIFICATION ON AQUATIC BIOTA

    EPA Science Inventory

    Acidification affects all components of biological communities in lakes and streams: microbes, algae, macrophytes, invertebrates, fish, amphibians, and other vertebrates that rely on aquatic ecosystems for habitat or food. echanisms of effect are both direct (toxic responses to c...

  13. Effects of stream topology on ecological community results from neutral models

    EPA Science Inventory

    While neutral theory and models have stimulated considerable literature, less well investigated is the effect of topology on neutral metacommunity model simulations. We implemented a neutral metacommunity model using two different stream network topologies, a widely branched netw...

  14. Ecological effects of combined organic or inorganic pollution on soil microbial activities

    Microsoft Academic Search

    Ping Gong; Tie-Heng Sun; Günter Beudert; Hermann H. Hahn

    1997-01-01

    Combined effects of organic or inorganic pollutants on soil microbial activities were investigated in field plots grown with\\u000a four types of covering plants. It was derived from this study that combined effects were dependent not only on the type and\\u000a dose of pollutants, addition of soda lime, plant type and season variation, but also on test parameters. When jointly added,

  15. Community ecology of invasions: direct and indirect effects of multiple invasive species on aquatic communities.

    PubMed

    Preston, Daniel L; Henderson, Jeremy S; Johnson, Pieter T J

    2012-06-01

    With many ecosystems now supporting multiple nonnative species from different trophic levels, it can be challenging to disentangle the net effects of invaders within a community context. Here, we combined wetland surveys with a mesocosm experiment to examine the individual and combined effects of nonnative fish predators and nonnative bullfrogs on aquatic communities. Among 139 wetlands, nonnative fish (bass, sunfish, and mosquitofish) negatively influenced the probability of occupancy of Pacific treefrogs (Pseudacris regilla), but neither invader correlated strongly with occupancy by California newts (Taricha torosa), western toads (Anaxyrus boreas), or California red-legged frogs (Rana draytonii). In mesocosms, mosquitofish dramatically reduced the abundance of zooplankton and palatable amphibian larvae (P. regilla and T. torosa), leading to increases in nutrient concentrations and phytoplankton (through loss of zooplankton), and rapid growth of unpalatable toad larvae (through competitive release). Bullfrog larvae reduced the growth of native anurans but had no effect on survival. Despite strong effects on natives, invaders did not negatively influence one another, and their combined effects were additive. Our results highlight how the net effects of multiple nonnative species depend on the trophic level of each invader, the form and magnitude of invader interactions, and the traits of native community members. PMID:22834365

  16. Plant Ecology An Introduction

    E-print Network

    Cochran-Stafira, D. Liane

    1 Plant Ecology An Introduction Ecology as a Science Study of the relationships between living and causes of the abundance and distribution of organisms Ecology as a Science We'll use the perspective of terrestrial plants Basic ecology - ecological principles Applied ecology - application of principles

  17. Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions.

    PubMed

    Xiao, Jun; Wang, Ya-Feng; Shi, Peng; Yang, Lei; Chen, Li-Ding

    2014-11-01

    Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period. PMID:25112841

  18. Ecological effects of cell-level processes: genome size, functional traits and regional abundance of herbaceous plant species

    PubMed Central

    Herben, Tomáš; Suda, Jan; Klimešová, Jitka; Mihulka, Stanislav; ?íha, Pavel; Šímová, Irena

    2012-01-01

    Background and Aims Genome size is known to be correlated with a number of phenotypic traits associated with cell sizes and cell-division rates. Genome size was therefore used as a proxy for them in order to assess how common plant traits such as height, specific leaf area and seed size/number predict species regional abundance. In this study it is hypothesized that if there is residual correlation between genome size and abundance after these traits are partialled out, there must be additional ecological effects of cell size and/or cell-division rate. Methods Variation in genome size, plant traits and regional abundance were examined in 436 herbaceous species of central European flora, and relationships were sought for among these variables by correlation and path analysis. Key Results Species regional abundance was weakly but significantly correlated with genome size; the relationship was stronger for annuals (R2 = 0·145) than for perennials (R2 = 0·027). In annuals, genome size was linked to abundance via its effect on seed size, which constrains seed number and hence population growth rate. In perennials, it weakly affected (via height and specific leaf area) competitive ability. These relationships did not change qualitatively after phylogenetic correction. In both annuals and perennials there was an unresolved effect of genome size on abundance. Conclusions The findings indicate that additional predictors of regional abundance should be sought among variables that are linked to cell size and cell-division rate. Signals of these cell-level processes remain identifiable even at the landscape scale, and show deep differences between perennials and annuals. Plant population biology could thus possibly benefit from more systematic use of indicators of cell-level processes. PMID:22628380

  19. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES

    EPA Science Inventory

    SCIENCE QUESTIONS: -Does gene flow occur from genetically modified (GM) crop plants to compatible plants? -How can it be measured? -Are there ecological consequences of GM crop gene flow to plant communities? RESEARCH: The objectives ...

  20. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan. Topical report, October 1990--August 1992

    SciTech Connect

    Rastorfer, J.R. [Chicago State Univ., IL (United States). Dept. of Biological Sciences; Van Dyke, G.D.; Zellmer, S.D.; Wilkey, P.L. [Argonne National Lab., IL (United States)

    1995-04-01

    This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth wetland sites mapped Lenawee soils were selected in Midland County, Michigan: Site 1, a younger stand subjected to recent selective logging, and Site 2, a more mature stand. The collection of ecological data to analyze plant succession on the right-of-way (ROW) and the effects of the developing ROW plant communities on adjacent forest communities was initiated in 1989. Cover class estimates were made for understory and ROW plant species on the basis of 1 {times} 1{minus}m quadrats. Individual stem diameters and species counts were recorded for overstory plants in 10{minus}m quadrats. Although long-term studies have not been completed, firm baseline data were established for comparative analyses with future sampling. Current data indicate that vegetation became well-established on the ROW within one year and subsequently increased in coverage. About 65% of the species were wetland indicators, and the dominants included seeded and natural invading species; nevertheless, some elements of the original flora regenerated and persist. The plants of the ecotone understories of both sites changed from their original composition as a result of the installation of the gas pipeline. Although some forest species persist at both sites, the ecotone of Site I was influenced more by the seeded species, whereas the natural invaders were more important at Site 2.