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Sample records for deleterious ecological effects

  1. Quantifying dominance and deleterious effect on human disease genes

    PubMed Central

    Osada, Naoki; Mano, Shuhei; Gojobori, Jun

    2009-01-01

    Human genes responsible for inherited diseases are important for the understanding of human disease. We investigated the degree of polymorphism and divergence in the human disease genes to elucidate the effect of natural selection on human disease genes. In particular, the effect of disease dominance was incorporated into the analysis. Both dominant disease genes (DDG) and recessive disease genes (RDG) had a higher mutation rate per site and encoded longer proteins than the nondisease genes, which exposed the disease genes to a faster flux of new mutations. Using an unbiased polymorphism dataset, we found that, proportionally, RDG harbor more nonsynonymous polymorphisms compared with DDG. We estimated the selection intensity on the disease genes using polymorphism and divergence data and determined whether the different patterns of polymorphism and divergence between DDG and RDG could be explained by the difference in only dominance. Even after the dominance effect was considered, the selection intensity on RDG was significantly different from DDG, suggesting that the deleterious effect of the dominant and recessive disease mutations are fundamentally different. PMID:19139396

  2. 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

  3. Expected Effect of Deleterious Mutations on Within-Host Adaptation of Pathogens

    PubMed Central

    2015-01-01

    ABSTRACT Adaptation is a common theme in both pathogen emergence, for example, in zoonotic cross-species transmission, and pathogen control, where adaptation might limit the effect of the immune response and antiviral treatment. When such evolution requires deleterious intermediate mutations, fitness ridges and valleys arise in the pathogen's fitness landscape. The effect of deleterious intermediate mutations on within-host pathogen adaptation is examined with deterministic calculations, appropriate for pathogens replicating in large populations with high error rates. The effect of deleterious intermediate mutations on pathogen adaptation is smaller than their name might suggest: when two mutations are required and each individual single mutation is fully deleterious, the pathogen can jump across the fitness valley by obtaining two mutations at once, leading to a proportion of adapted mutants that is 20-fold lower than that in the situation where the fitness of all mutants is neutral. The negative effects of deleterious intermediates are typically substantially smaller and outweighed by the fitness advantages of the adapted mutant. Moreover, requiring a specific mutation order has a substantially smaller effect on pathogen adaptation than the effect of all intermediates being deleterious. These results can be rationalized when the number of routes of mutation available to the pathogen is calculated, providing a simple approach to estimate the effect of deleterious mutations. The calculations discussed here are applicable when the effect of deleterious mutations on the within-host adaptation of pathogens is assessed, for example, in the context of zoonotic emergence, antigenic escape, and drug resistance. IMPORTANCE Adaptation is critical for pathogens after zoonotic transmission into a new host species or to achieve antigenic immune escape and drug resistance. Using a deterministic approach, the effects of deleterious intermediate mutations on pathogen adaptation were calculated while avoiding commonly made simplifications that do not apply to large pathogen populations replicating with high mutation rates. Perhaps unexpectedly, pathogen adaptation does not halt when the intermediate mutations are fully deleterious. The negative effects of deleterious mutations are substantially outweighed by the fitness gains of adaptation. To gain an understanding of the effect of deleterious mutations on pathogen adaptation, a simple approach that counts the number of routes available to the pathogen with and without deleterious intermediate mutations is introduced. This methodology enables a straightforward calculation of the proportion of the pathogen population that will cross a fitness valley or traverse a fitness ridge, without reverting to more complicated mathematical models. PMID:26109724

  4. [Deleterious effects of smoking on the musculoskeletal system].

    PubMed

    Duthon, V B; Ozturk, M; El-Achachi, S; Menetrey, J

    2014-07-16

    Tobacco smoking has important negative effects on the musculoskeletal system: decrease of bone mineral density, increase of the risk of injury, illness, and perioperative complications such as fracture-healing complications and wound complications. Orthopaedic surgeons should inform all patients of the increased risks associated with active smoking in the perioperative period and should encourage them to quit smoking four to eight weeks in advance of the proposed procedure. PMID:25141568

  5. 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.

  6. Deleterious Effects of Mycotoxin Combinations Involving Ochratoxin A

    PubMed Central

    Klari?, Maja egvi?; Rai?, Dubravka; Peraica, Maja

    2013-01-01

    Ochratoxin A (OTA) is a nephrotoxic mycotoxin with carcinogenic properties. Its presence was detected in various foodstuffs all over the world but with significantly higher frequency and concentrations in areas with endemic nephropathy (EN). Even though food is often contaminated with more than one mycotoxin, earlier studies focused on the occurrence and toxicology of only OTA. Only a limited number of surveys showed that OTA co-occurs in food with mycotoxins (citrinin-CIT, penicilic acid, fumonisin B1-FB1, aflatoxins-AF) which exert nephrotoxic, carcinogenic or carcinogen-promoting activity. This review summarises the findings on OTA and its co-occurrence with the mentioned mycotoxins in food as well as experimental data on their combined toxicity. Most of the tested mycotoxin mixtures involving OTA produced additive or synergistic effects in experimental models suggesting that these combinations represent a significant health hazard. Special attention should be given to mixtures that include carcinogenic and cancer-promoting mycotoxins. PMID:24189375

  7. Deleterious effects of nonthermal electrons in shock ignition concept.

    PubMed

    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 μm. 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. PMID:24730956

  8. Illuminating the deleterious effects of light at night

    PubMed Central

    Nelson, Randy J.

    2011-01-01

    Technological advances, while providing many benefits, often create circumstances that differ from the conditions in which we evolved. With the wide-spread adoption of electrical lighting during the 20th century, humans became exposed to bright and unnatural light at night for the first time in their evolutionary history. Electrical lighting has led to the wide-scale practice of 24-hour shift-work and has meant that what were once just daytime activities now run throughout the night; in many ways Western society now functions on a 24-hour schedule. Recent research suggests that this gain in freedom to function throughout the night may also come with significant repercussions. Disruption of our naturally evolved light and dark cycles can result in a wide range of physiological and behavioral changes with potentially serious medical implications. In this article we will discuss several mechanisms through which light at night may exert its effects on cancer, mood, and obesity, as well as potential ways to ameliorate the impact of light at night. PMID:21941596

  9. 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)

  10. Separating multiple, short-term deleterious effects of saline solutions to the growth of cowpea seedlings

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reductions in plant growth due to salinity are of global importance in natural and agricultural landscapes. Short-term (48 h) solution culture experiments studied 404 treatments with seedlings of cowpea (Vigna unguiculata (L.) Walp. cv. Caloona) to examine the multiple deleterious effects of Ca, Mg...

  11. DELETERIOUS RHIZOBACTERIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Deleterious rhizobacteria (DRB) are predominantly saprophytic bacteria that aggressively colonize plant seeds, roots and rhizospheres and readily metabolize organic substances released by plant tissues. Unlike typical phytopathogens, DRB do not invade and parasitize vascular tissues; DRB that inhabi...

  12. 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

  13. Absence of deleterious effects of chronic microwave radiation on the eyes of rhesus monkeys

    SciTech Connect

    McAfee, R.D.; Ortiz-Lugo, R.; Bishop, R.; Gordon, R.

    1983-10-01

    Microwave irradiation of rhesus monkeys' eyes at 9.31 and 2.45 GHz and at an average power density of 150 mW per centimeter square is reported. Irradiation, beginning in 1976, of 17 monkeys (Macaca mulatta) was accomplished without restraint or anesthesia by training the monkeys to irradiate themselves. To data microwave radiation of these monkeys has not resulted in deleterious ocular effects.

  14. Identification of Deleterious SNPs and Their Effects on Structural Level in CHRNA3 Gene.

    PubMed

    Chandramohan, Vivek; Nagaraju, Navya; Rathod, Shrikant; Kaphle, Anubhav; Muddapur, Uday

    2015-08-01

    The aim of our study is to identify probable deleterious genetic variations that can alter the expression and the function of the CHRNA3 gene using in silico methods. Of the 2305 SNPs identified in the CHRNA3 gene, 115 were found to be non-synonymous and 12 and 15 nsSNPs were found to be in the 5' and 3' UTRs, respectively. Further, out of the 115 nsSNPs investigated, eight were predicted to be deleterious by both SIFT and PredictSNP servers. The major mutations predicted to affect the structure of the protein are phenylalanine to valine (Y43V) and lysine to asparagine (K216N) as shown by the trajectory run in molecular dynamics studies. The random transition of the protein structures over the simulation period caused by these mutations hints at how the native state is distorted which could lead to the loss of structural stability and functionality of the nicotinic acetylcholine receptors subunit ?-3 protein. Based on this work, we propose that the nsSNP with SNP id of rs75495285 and rs76821682 will have comparatively more deleterious effects than the other predicted mutations in destabilizing the protein structure. PMID:26002565

  15. The effect of overdominance on characterizing deleterious mutations in large natural populations.

    PubMed Central

    Li, J L; Li, J; Deng, H W

    1999-01-01

    Alternatives to the mutation-accumulation approach have been developed to characterize deleterious genomic mutations. However, they all depend on the assumption that the standing genetic variation in natural populations is solely due to mutation-selection (M-S) balance and therefore that overdominance does not contribute to heterosis. Despite tremendous efforts, the extent to which this assumption is valid is unknown. With different degrees of violation of the M-S balance assumption in large equilibrium populations, we investigated the statistical properties and the robustness of these alternative methods in the presence of overdominance. We found that for dominant mutations, estimates for U (genomic mutation rate) will be biased upward and those for h (mean dominance coefficient) and s (mean selection coefficient), biased downward when additional overdominant mutations are present. However, the degree of bias is generally moderate and depends largely on the magnitude of the contribution of overdominant mutations to heterosis or genetic variation. This renders the estimates of U and s not always biased under variable mutation effects that, when working alone, cause U and s to be underestimated. The contributions to heterosis and genetic variation from overdominant mutations are monotonic but not linearly proportional to each other. Our results not only provide a basis for the correct inference of deleterious mutation parameters from natural populations, but also alleviate the biggest concern in applying the new approaches, thus paving the way for reliably estimating properties of deleterious mutations. PMID:9927478

  16. Effects of chronic hypergravity: from adaptive to deleterious responses in growing mouse skeleton.

    PubMed

    Gnyubkin, Vasily; Guignandon, Alain; Laroche, Norbert; Vanden-Bossche, Arnaud; Normand, Myriam; Lafage-Proust, Marie-Hlne; Vico, Laurence

    2015-10-15

    One of the most important but least studied environmental factors playing a major role in bone physiology is gravity. While the knowledge of deleterious effects of microgravity on the skeleton is expanding, little is known about hypergravity and its osteogenic potential. Centrifugation was used to assess effects of 21-day continuous 2- or 3-g acceleration on femur and L2-vertebra of 7-wk-old male C57BL/6 mice. Under 3 g, body mass growth slowed down, and deleterious skeletal effects were found (P < 0.05 compared with control): cortical thinning, osteoclasts surface increase (+41% in femur, +20% in vertebra), and bone formation rate decrease (-34% in femur, -38% in vertebra). A 2-g centrifugation did not reduce body mass and improved trabecular volume (+18% in femur, +13% in vertebra) and microarchitecture (+32% connectivity density in femur, +9% trabecular thickness in vertebra, P < 0.05 compared with control). Centrifugation at 2 g also decreased osteoclast surfaces (-36% in femur, -16% in vertebra) and increased the extent of mineralized surfaces (+31% in femur, +48% in vertebra, P < 0.05 compare to control). Quantitative immunohistochemistry revealed an increase of dentin matrix acidic phosphoprotein 1 (DMP1) and decrease of sclerostin (+60% and -35% respectively, P < 0.001 compared with control) in the femur cortex of 2-g mice. In the distal femur metaphysis, the number and volume of blood vessels increased by 22 and 44%, respectively (P < 0.05 compared with control). In conclusion, the effects of continuous hypergravity were bone compartment-specific and depended on the gravity level, with a threshold between beneficial 2-g and deleterious 3-g effects. PMID:26228999

  17. Can Platelet-Rich Plasma Protect Rat Achilles Tendons From the Deleterious Effects of Triamcinolone Acetonide?

    PubMed Central

    Muto, Tomoyuki; Kokubu, Takeshi; Mifune, Yutaka; Inui, Atsuyuki; Sakata, Ryosuke; Harada, Yoshifumi; Takase, Fumiaki; Ueda, Yasuhiro; Kuroda, Ryosuke; Kurosaka, Masahiro

    2015-01-01

    Background Triamcinolone acetonide (TA) injections are widely used for tendinitis but have deleterious effects, including tendon degeneration or tendon rupture. Purpose To investigate whether adding platelet-rich plasma (PRP), a blood fraction that participates in tissue repair processes, to TA can prevent its deleterious effects. Study Design Controlled laboratory study. Methods Rat Achilles tendons were injected with TA, TA + PRP, PRP alone, or saline (control). Biomechanical testing and histological analyses were performed on Achilles tendons 1 week after injections. Results The maximum failure loads in the control, TA, TA + PRP, and PRP groups were 31.7 ± 2.3, 19.0 ± 3.6, 31.0 ± 7.1, and 30.2 ± 6.8 N, respectively. The tendon stiffness in the control, TA, TA + PRP, and PRP groups was 12.1 ± 1.8, 7.5 ± 1.8, 11.0 ± 2.8, and 11.3 ± 2.5 N/mm, respectively. The maximum failure load and stiffness were significantly lower in the TA group compared with the other 3 groups. There was no significant difference between the TA + PRP and control groups. Cell invasions, vacuolation, collagen attenuation, and increased type III collagen expression were histologically observed in the TA group; however, these changes were prevented by the simultaneous administration of PRP. Conclusion Administering PRP may prevent deleterious effects caused by TA; therefore, PRP may be used as a protective agent in clinical situations. Clinical Relevance PRP can be useful as a protective agent for sports injury patients receiving local corticosteroid injections. PMID:26673355

  18. One-Nanometer Thin Monolayers Remove the Deleterious Effect of Substrate Defects in Molecular Tunnel Junctions.

    PubMed

    Jiang, Li; Sangeeth, C S Suchand; Yuan, Li; Thompson, Damien; Nijhuis, Christian A

    2015-10-14

    Defects in self-assembled monolayer (SAMs) based junctions cause the largest deviation between predicted and measured values of the tunnelling current. We report the remarkable, seemingly counterintuitive finding that shorter, less-ordered SAMs provide, unlike taller crystalline-like SAMs, higher quality tunnelling barriers on defective substrates, which points to self-repair of liquid-like SAMs on defects. The molecular dynamics show that short-chain molecules can more easily rotate into low-density boundary regions and smoothen out defects than thick solid-like SAMs. Our findings point to an attractive means of removing their deleterious effects simply by using flexible molecules. PMID:26340232

  19. High-protein-low-carbohydrate diet: deleterious metabolic and cardiovascular effects depend on age.

    PubMed

    Bedarida, Tatiana; Baron, Stephanie; Vessieres, Emilie; Vibert, Francoise; Ayer, Audrey; Marchiol-Fournigault, Carmen; Henrion, Daniel; Paul, Jean-Louis; Noble, Florence; Golmard, Jean-Louis; Beaudeux, Jean-Louis; Cottart, Charles-Henry; Nivet-Antoine, Valerie

    2014-09-01

    High-protein-low-carbohydrate (HP-LC) diets have become widespread. Yet their deleterious consequences, especially on glucose metabolism and arteries, have already been underlined. Our previous study (2) has already shown glucose intolerance with major arterial dysfunction in very old mice subjected to an HP-LC diet. The hypothesis of this work was that this diet had an age-dependent deleterious metabolic and cardiovascular outcome. Two groups of mice, young and adult (3 and 6 mo old), were subjected for 12 wk to a standard or to an HP-LC diet. Glucose and lipid metabolism was studied. The cardiovascular system was explored from the functional stage with Doppler-echography to the molecular stage (arterial reactivity, mRNA, immunohistochemistry). Young mice did not exhibit any significant metabolic modification, whereas adult mice presented marked glucose intolerance associated with an increase in resistin and triglyceride levels. These metabolic disturbances were responsible for cardiovascular damages only in adult mice, with decreased aortic distensibility and left ventricle dysfunction. These seemed to be the consequence of arterial dysfunctions. Mesenteric arteries were the worst affected with a major oxidative stress, whereas aorta function seemed to be maintained with an appreciable role of cyclooxygenase-2 to preserve endothelial function. This study highlights for the first time the age-dependent deleterious effects of an HP-LC diet on metabolism, with glucose intolerance and lipid disorders and vascular (especially microvessels) and cardiac functions. This work shows that HP-LC lead to equivalent cardiovascular alterations, as observed in very old age, and underlines the danger of such diet. PMID:25015969

  20. 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

  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. 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

  3. Are There Deleterious Cardiac Effects of Acute and Chronic Endurance Exercise?

    PubMed

    Eijsvogels, Thijs M H; Fernandez, Antonio B; Thompson, Paul D

    2016-01-01

    Multiple epidemiological studies document that habitual physical activity reduces the risk of atherosclerotic cardiovascular disease (ASCVD), and most demonstrate progressively lower rates of ASCVD with progressively more physical activity. Few studies have included individuals performing high-intensity, lifelong endurance exercise, however, and recent reports suggest that prodigious amounts of exercise may increase markers for, and even the incidence of, cardiovascular disease. This review examines the evidence that extremes of endurance exercise may increase cardiovascular disease risk by reviewing the causes and incidence of exercise-related cardiac events, and the acute effects of exercise on cardiovascular function, the effect of exercise on cardiac biomarkers, including "myocardial" creatine kinase, cardiac troponins, and cardiac natriuretic peptides. This review also examines the effect of exercise on coronary atherosclerosis and calcification, the frequency of atrial fibrillation in aging athletes, and the possibility that exercise may be deleterious in individuals genetically predisposed to such cardiac abnormalities as long QT syndrome, right ventricular cardiomyopathy, and hypertrophic cardiomyopathy. This review is to our knowledge unique because it addresses all known potentially adverse cardiovascular effects of endurance exercise. The best evidence remains that physical activity and exercise training benefit the population, but it is possible that prolonged exercise and exercise training can adversely affect cardiac function in some individuals. This hypothesis warrants further examination. PMID:26607287

  4. Female rats are more susceptible to the deleterious effects of paradoxical sleep deprivation on cognitive performance.

    PubMed

    Hajali, Vahid; Sheibani, Vahid; Esmaeili-Mahani, Saeed; Shabani, Mohammad

    2012-03-17

    Paradoxical sleep deprivation (PSD) may alter subsequent learning and memory capacity. There are differences in both the intensity and direction of responses of the male and female species to the same environmental stimuli and experimental conditions. In the present study, we examined the extent of the effects of PSD for 72h on spatial learning and memory, anxiety-like behavior, corticosterone levels, and the body weight in male as well as in intact and ovariectomized (OVX) female Wistar rats. Multiple platform method was used for PSD induction. Spatial learning and memory and anxiety-like behavior were determined using Morris water maze (MWM) task and open field test, respectively. The data showed that PSD could not significantly affect subsequent spatial learning and short-term memory in male rats, while it significantly impaired the performance of the intact and OVX female rats. The PSD-intact and -OVX female rats showed more memory impairment than the PSD-male animals. Those impairments do not appear to be due to elevated stress level, since the plasma corticosterone did not significantly change following PSD induction. The open field data showed that PSD significantly reduced anxiety-like behavior in all experimental groups. In addition, PSD had a reducing effect on the mean body weight of female groups. Such results suggest that the female rats are more vulnerable to the deleterious effects of sleep loss on cognitive performance. PMID:22192378

  5. Doping dose of salbutamol and exercise: deleterious effect on cancellous and cortical bones in adult rats.

    PubMed

    Bonnet, N; Benhamou, C L; Beaupied, H; Laroche, N; Vico, L; Dolleans, E; Courteix, D

    2007-04-01

    Animal studies suggest that bone remodeling is under beta-adrenergic control via the sympathetic nervous system. To our knowledge, the impact of beta-agonist substances, at doping doses, has not been studied in adult rats. The purpose of this study was to examine the effects of salbutamol injections with or without treadmill exercise on trabecular and cortical bone in adult rats. Adult (36 wk of age) female Wistar rats (n = 56) were treated with salbutamol (3 mg.kg(-1).day(-1) sc, 5 days/wk) or vehicle (sham) with or without subsequent treadmill exercise (13 m/min, 60 min/day, 5 days/wk) for 10 wk. Tibial and femoral bone mineral density was analyzed by dual-energy X-ray absorptiometry. Metaphysic trabecular bone structure was analyzed by micro-CT at the time of the animals' death. Bone cell activities were assessed histomorphometrically. After 10 wk, the increase in bone mineral density was less in salbutamol-treated than in sham rats (+3.3% vs. +12.4%, P < 0.05), and trabecular parameters were altered and bone resorption was increased in salbutamol-treated rats compared with controls. The negative effect on bone architecture in salbutamol-treated rats persisted, even with treadmill exercise. These results confirm the deleterious effect of beta(2)-agonists on bone mass during chronic treatment and describe its effects on bone mechanical properties in adult rats. Bone loss occurred independently of a salbutamol-induced anabolic effect on muscle mass and was equally severe in sedentary and exercising rats, despite a beneficial effect of exercise on the extrinsic and intrinsic energy to ultimate strain. These bone effects may have important consequences in athletes who use salbutamol as a doping substance. PMID:17185495

  6. CoA protects against the deleterious effects of caloric overload in Drosophila.

    PubMed

    Palanker Musselman, Laura; Fink, Jill L; Baranski, Thomas J

    2016-03-01

    We developed a Drosophila model of T2D in which high sugar (HS) feeding leads to insulin resistance. In this model, adipose TG storage is protective against fatty acid toxicity and diabetes. Initial biochemical and gene expression studies suggested that deficiency in CoA might underlie reduced TG synthesis in animals during chronic HS feeding. Focusing on the Drosophila fat body (FB), which is specialized for TG storage and lipolysis, we undertook a series of experiments to test the hypothesis that CoA could protect against the deleterious effects of caloric overload. Quantitative metabolomics revealed a reduction in substrate availability for CoA synthesis in the face of an HS diet. Further reducing CoA synthetic capacity by expressing FB-specific RNAi targeting pantothenate kinase (PK orfumble) or phosphopantothenoylcysteine synthase (PPCS) exacerbated HS-diet-induced accumulation of FFAs. Dietary supplementation with pantothenic acid (vitamin B5, a precursor of CoA) was able to ameliorate HS-diet-induced FFA accumulation and hyperglycemia while increasing TG synthesis. Taken together, our data support a model where free CoA is required to support fatty acid esterification and to protect against the toxicity of HS diets. PMID:26805007

  7. Ursolic acid derivative ameliorates streptozotocin-induced diabestic bone deleterious effects in mice

    PubMed Central

    Yu, Su-Guo; Zhang, Cheng-Jie; Xu, Xiu-E; Sun, Ji-Hua; Zhang, Li; Yu, Peng-Fei

    2015-01-01

    Objective: This study was performed to investigate bone deteriorations of diabetic mice in response to the treatment of ursolic acid derivative (UAD). 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: UAD showed a greater increase in bone Ca, BMD and significantly increased FGF-23 and OCN, reduced PTH and CTX in diabetic mice. UAD reversed STZ-induced trabecular deleterious effects and stimulated bone remodeling. The treatment of STZ group with UAD significantly elevated the ratio of OPG/RANKL. Moreover, insulin and IGF-1 showed a negative correlation with both FBG and Hb1Ac in STZ group. We attributed down-regulating the level of Hb1Ac in diabetic mice to that ursolic acid derivative could primely control blood sugar levels. After analyzing of two adipocyte markers, PPAR? and aP2, increased expression in the tibias of diabetic mice, and UAD could improve STZ-induced adipocyte dysfunction. Conclusions: These results demonstrated that UAD could ameliorate STZ-induced bone deterioration through improving adipocyte dysfunction and enhancing new bone formation and inhibiting absorptive function of osteoclast in the bone of diabetic mice. PMID:26097549

  8. mir33 Inhibition Overcomes Deleterious Effects of Diabetes on Atherosclerosis Plaque Regression in Mice

    PubMed Central

    Distel, Emilie; Barrett, Tessa J.; Chung, Kellie; Girgis, Natasha M.; Parathath, Saj; Essau, Christine C.; Murphy, Andrew J.; Moore, Kathryn J.; Fisher, Edward A.

    2014-01-01

    Rationale Diabetes increases cardiovascular disease risk in humans and remains elevated despite cholesterol-lowering therapy with statins. Consistent with this, in mouse models diabetes impairs atherosclerosis plaque regression after aggressive cholesterol-lowering. miR33 is a key negative regulator of the reverse cholesterol transport factors, ABCA1 and HDL, which suggested that its inhibition may overcome this impairment. Objective To assess the effects of miR33 inhibition on atherosclerosis regression in diabetic mice. Methods and Results Reversa mice, which are deficient in the LDL receptor and in which hypercholesterolemia is reversed by conditional inactivation of the microsomal triglyceride transfer protein (Mttp) gene, were placed on an atherogenic diet for 16 weeks, then either made diabetic by STZ injection or kept normoglycemic. Lipid-lowering was induced by Mttp inactivation and mice were treated with anti-miR33 or control oligonucleotides. Whereas regression was impaired in diabetic mice treated with control oligonucleotides, anti-miR33 treatment decreased plaque macrophage content and inflammatory gene expression in these mice. The decreased macrophage content in anti-miR33-treated diabetic mice was associated with a blunting of hyperglycemia-induced monocytosis and reduced monocyte recruitment to the plaque, which was traced to an inhibition of the proliferation of bone marrow monocyte precursors associated with the upregulation of their Abca1. Conclusions miR33 inhibition overcomes deleterious effects of diabetes in atherosclerosis regression in mice, which suggests a therapeutic strategy in diabetic patients, who remain at elevated cardiovascular disease risk despite plasma cholesterol lowering. PMID:25201910

  9. European ACP1*C Allele Has Recessive Deleterious Effects on Early Life Viability

    PubMed Central

    WILDER, JASON A.; HAMMER, MICHAEL F.

    2005-01-01

    The acid phosphatase locus (ACP1) is a classical polymorphism that has been surveyed in hundreds of human populations worldwide. Among individuals of European ancestry, the ACP1*C allele occurs with an average frequency of approximately 0.05, whereas it is nearly absent in all other human populations. It has been hypothesized that this allele is maintained by over dominant selection among European populations. Here, we analyze ACP1 protein polymorphism data from more than 50,000 individuals previously surveyed in 67 populations across Europe as well as inheritance data from more than 6,000 European parentoffspring pairs to assess the signature of natural selection currently acting on this allele. Although we see a significant excess of ACP1*C heterozygotes relative to HardyWeinberg expectations, we find no evidence that natural selection favors ACP1*C heterozygotes. Instead, ACP1*C appears to have a strongly deleterious and recessive fitness effect. We observed only 48.9% of expected homozygous offspring from heterozygous parents and significantly fewer homozygotes than expected within populations. Because parentoffspring pairs indicate a significant deficiency of ACP1*C homozygotes, we infer that viability selection is acting on ACP1*C homozygotes very early in life, perhaps before birth. We estimate that approximately 1.2% of all couples of European ancestry are composed of individuals who both carry the APC1*C allele. As such, selection against ACP1*C homozygotes may represent a nonnegligible contribution to the overall number of spontaneous abortions among women of European ancestry and may cause substantial fertility reductions among some combinations of parental genotypes. PMID:15974295

  10. Endurance exercise training blunts the deleterious effect of high-fat feeding on whole body efficiency

    PubMed Central

    Holloway, Cameron J.; Murray, Andrew J.; Knight, Nicholas S.; Carter, Emma E.; Kemp, Graham J.; Thompson, Campbell H.; Tyler, Damian J.; Neubauer, Stefan; Robbins, Peter A.; Clarke, Kieran

    2011-01-01

    We recently showed that a week-long, high-fat diet reduced whole body exercise efficiency in sedentary men by >10% (Edwards LM, Murray AJ, Holloway CJ, Carter EE, Kemp GJ, Codreanu I, Brooker H, Tyler DJ, Robbins PA, Clarke K. FASEB J 25: 10881096, 2011). To test if a similar dietary regime would blunt whole body efficiency in endurance-trained men and, as a consequence, hinder aerobic exercise performance, 16 endurance-trained men were given a short-term, high-fat (70% kcal from fat) and a moderate carbohydrate (50% kcal from carbohydrate) diet, in random order. Efficiency was assessed during a standardized exercise task on a cycle ergometer, with aerobic performance assessed during a 1-h time trial and mitochondrial function later measured using 31P-magnetic resonance spectroscopy. The subjects then underwent a 2-wk wash-out period, before the study was repeated with the diets crossed over. Muscle biopsies, for mitochondrial protein analysis, were taken at the start of the study and on the 5th day of each diet. Plasma fatty acids were 60% higher on the high-fat diet compared with moderate carbohydrate diet (P < 0.05). However, there was no change in whole body efficiency and no change in mitochondrial function. Endurance exercise performance was significantly reduced (P < 0.01), most probably due to glycogen depletion. Neither diet led to changes in citrate synthase, ATP synthase, or mitochondrial uncoupling protein 3. We conclude that prior exercise training blunts the deleterious effect of short-term, high-fat feeding on whole body efficiency. PMID:21632846

  11. Juvenile idiopathic arthritis activity and function ability: deleterious effects in periodontal disease?

    PubMed

    Pugliese, Camila; van der Vinne, Roberta T A; Campos, Lucia M A; Guardieiro, Priscila R; Saviolli, Cynthia; Bonfá, Eloisa; Pereira, Rosa M R; Viana, Vilma S; Borba, Eduardo F; Silva, Clovis A

    2016-01-01

    The impact of juvenile idiopathic arthritis (JIA) in periodontal diseases is controversial probably due to gender and age heterogeneity. We therefore evaluated a homogeneous female post-pubertal JIA population for these conditions. Thirty-five JIA patients and 35 gender/age comparable healthy controls were evaluated according to demographic data, complete periodontal evaluation, fasting lipoproteins, and anti-lipoprotein lipase antibodies. JIA scores, laboratorial tests, X-rays, and treatment were also assessed. Current age was similar in JIA patients and controls (11.90 ± 2.0 vs. 12.50 ± 3.0 years, p = 0.289). Complete periodontal assessments revealed that gingival index, dental plaque, gingival bleeding, and clinical dental attachment indices were alike in JIA patients and controls (p > 0.05), except for gingival enlargement in former group (p < 0.0001). Further analysis of patients with and without gingivitis revealed that cyclosporine use was more often observed in JIA patients with gingivitis (37 vs. 0 %, p = 0.01), whereas no differences were evidenced in demographic, JIA scores, inflammatory markers, and lipid profile in both groups. Of note, two parameters of periodontal assessment were correlated with JIA scores [gingival index (GI) and Childhood Health Assessment Questionnaire (CHAQ) (r s  = +0.402, p = 0.020)] and plaque index (PI) and visual analog scale (VAS) physician (r s  = +0.430, p = 0.013). In addition, evaluation of dental assessment demonstrated that JIA activity scores had positive correlation with decayed, missing, and filled teeth (DMF-T) and junvenile athritis disease activity score (JADAS) (r s  = +0.364,p = 0.037), VAS physician (r s  = +0.401,p = 0.021) and VAS patient (r s  = +0.364,p = 0.037). We demonstrated, using rigorous criteria, that periodontal and dental condition in JIA is similar to controls. In spite of that, the finding of a correlation with disease parameters provides additional evidence that increased activity and reduced functional ability underlies the deleterious effect of JIA in oral health. PMID:26626632

  12. Systematic Mapping of Protein Mutational Space by Prolonged Drift Reveals the Deleterious Effects of Seemingly Neutral Mutations

    PubMed Central

    Rockah-Shmuel, Liat; Tth-Petrczy, gnes; Tawfik, Dan S.

    2015-01-01

    Systematic mappings of the effects of protein mutations are becoming increasingly popular. Unexpectedly, these experiments often find that proteins are tolerant to most amino acid substitutions, including substitutions in positions that are highly conserved in nature. To obtain a more realistic distribution of the effects of protein mutations, we applied a laboratory drift comprising 17 rounds of random mutagenesis and selection of M.HaeIII, a DNA methyltransferase. During this drift, multiple mutations gradually accumulated. Deep sequencing of the drifted gene ensembles allowed determination of the relative effects of all possible single nucleotide mutations. Despite being averaged across many different genetic backgrounds, about 67% of all nonsynonymous, missense mutations were evidently deleterious, and an additional 16% were likely to be deleterious. In the early generations, the frequency of most deleterious mutations remained high. However, by the 17th generation, their frequency was consistently reduced, and those remaining were accepted alongside compensatory mutations. The tolerance to mutations measured in this laboratory drift correlated with sequence exchanges seen in M.HaeIIIs natural orthologs. The biophysical constraints dictating purging in nature and in this laboratory drift also seemed to overlap. Our experiment therefore provides an improved method for measuring the effects of protein mutations that more closely replicates the natural evolutionary forces, and thereby a more realistic view of the mutational space of proteins. PMID:26274323

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

    PubMed Central

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

    2014-01-01

    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 non-synonymous 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 non-synonymous mutations faster than either modern humans or Neanderthals. To reconcile these findings with patterns that have been interpreted as evidence of 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, and instead are likely to be driven by other population genetic factors. PMID:25581429

  14. Deleterious effects of lard-enriched diet on tissues fatty acids composition and hypothalamic insulin actions.

    PubMed

    Dornellas, A P S; Watanabe, R L H; Pimentel, G D; Boldarine, V T; Nascimento, C M O; Oyama, L M; Ghebremeskel, K; Wang, Y; Bueno, A A; Ribeiro, E B

    2015-12-01

    Altered tissue fatty acid (FA) composition may affect mechanisms involved in the control of energy homeostasis, including central insulin actions. In rats fed either standard chow or a lard-enriched chow (high in saturated/low in polyunsaturated FA, HS-LP) for eight weeks, we examined the FA composition of blood, hypothalamus, liver, and retroperitoneal, epididymal and mesenteric adipose tissues. Insulin-induced hypophagia and hypothalamic signaling were evaluated after intracerebroventricular insulin injection. HS-LP feeding increased saturated FA content in adipose tissues and serum while it decreased polyunsaturated FA content of adipose tissues, serum, and liver. Hypothalamic C20:5n-3 and C20:3n-6 contents increased while monounsaturated FA content decreased. HS-LP rats showed hyperglycemia, impaired insulin-induced hypophagia and hypothalamic insulin signaling. The results showed that, upon HS-LP feeding, peripheral tissues underwent potentially deleterious alterations in their FA composition, whist the hypothalamus was relatively preserved. However, hypothalamic insulin signaling and hypophagia were drastically impaired. These findings suggest that impairment of hypothalamic insulin actions by HS-LP feeding was not related to tissue FA composition. PMID:26525379

  15. Oxidative Stress Is Related to the Deleterious Effects of Heme Oxygenase-1 in an In Vivo Neuroinflammatory Rat Model

    PubMed Central

    Tronel, Claire; Rochefort, Gal Y.; Arlicot, Nicolas; Bodard, Sylvie; Chalon, Sylvie; Antier, Daniel

    2013-01-01

    Heme oxygenase-1 (HO-1) induction is associated with beneficial or deleterious effects depending on the experimental conditions adopted and the neurodegenerative rodent models used. The present study aimed first to evaluate the effects of cerebral HO-1 induction in an in vivo rat model of neuroinflammation by intrastriatal injection of quinolinic acid (QA) and secondly to explore the role played by reactive oxygen species (ROS) and free iron (Fe2+) derived from heme catabolism promoted by HO-1. Chronic I.P. treatment with the HO-1 inductor and substrate hemin was responsible for a significant dose-related increase of cerebral HO-1 production. Brain tissue loss, microglial activation, and neuronal death were significantly higher in rats receiving QA plus hemin (H-QA) versus QA and controls. Significant increase of ROS production in H-QA rat brain was inhibited by the specific HO-1 inhibitor ZnPP which supports the idea that ROS level augmentation in hemin-treated animals is a direct consequence of HO-1 induction. The cerebral tissue loss and ROS level in hemin-treated rats receiving the iron chelator deferoxamine were significantly decreased, demonstrating the involvement of Fe2+in brain ROS production. Therefore, the deleterious effects of HO-1 expression in this in vivo neuroinflammatory model were linked to a hyperproduction of ROS, itself promoted by free iron liberation. PMID:23533686

  16. Mutation accumulation in real branches: fitness assays for genomic deleterious mutation rate and effect in large-statured plants.

    PubMed

    Schultz, Stewart T; Scofield, Douglas G

    2009-08-01

    The genomic deleterious mutation rate and mean effect are central to the biology and evolution of all species. Large-statured plants, such as trees, are predicted to have high mutation rates due to mitotic mutation and the absence of a sheltered germ line, but their size and generation time has hindered genetic study. We develop and test approaches for estimating deleterious mutation rates and effects from viability comparisons within the canopy of large-statured plants. Our methods, inspired by E. J. Klekowski, are a modification of the classic Bateman-Mukai mutation-accumulation experiment. Within a canopy, cell lineages accumulate mitotic mutations independently. Gametes or zygotes produced at more distal points by these cell lineages contain more mitotic mutations than those at basal locations, and within-flower selfs contain more homozygous mutations than between-flower selfs. The resulting viability differences allow demonstration of lethal mutation with experiments similar in size to assays of genetic load and allow estimates of the rate and effect of new mutations with moderate precision and bias similar to that of classic mutation-accumulation experiments in small-statured organisms. These methods open up new possibilities with the potential to provide valuable new insights into the evolutionary genetics of plants. PMID:19548838

  17. Methyl donor supplementation in rats reverses the deleterious effect of maternal separation on depression-like behaviour.

    PubMed

    Paternain, Laura; Martisova, Eva; Campión, Javier; Martínez, J Alfredo; Ramírez, Maria J; Milagro, Fermin I

    2016-02-15

    Adverse early life events are associated with altered stress responsiveness and metabolic disturbances in the adult life. Dietary methyl donor supplementation could be able to reverse the negative effects of maternal separation by affecting DNA methylation in the brain. In this study, maternal separation during lactation reduced body weight gain in the female adult offspring without affecting food intake, and altered total and HDL-cholesterol levels. Also, maternal separation induced a cognitive deficit as measured by NORT and an increase in the immobility time in the Porsolt forced swimming test, consistent with increased depression-like behaviour. An 18-week dietary supplementation with methyl donors (choline, betaine, folate and vitamin B12) from postnatal day 60 also reduced body weight without affecting food intake. Some of the deleterious effects induced by maternal separation, such as the abnormal levels of total and HDL-cholesterol, but especially the depression-like behaviour as measured by the Porsolt test, were reversed by methyl donor supplementation. Also, the administration of methyl donors increased total DNA methylation (measured by immunohistochemistry) and affected the expression of insulin receptor in the hippocampus of the adult offspring. However, no changes were observed in the DNA methylation status of insulin receptor and corticotropin-releasing hormone (CRH) promoter regions in the hypothalamus. In summary, methyl donor supplementation reversed some of the deleterious effects of an early life-induced model of depression in rats and altered the DNA methylation profile in the brain. PMID:26628207

  18. Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations

    PubMed Central

    Kehdy, Fernanda S. G.; Gouveia, Mateus H.; Machado, Moara; Magalhães, Wagner C. S.; Horimoto, Andrea R.; Horta, Bernardo L.; Moreira, Rennan G.; Leal, Thiago P.; Scliar, Marilia O.; Soares-Souza, Giordano B.; Rodrigues-Soares, Fernanda; Araújo, Gilderlanio S.; Zamudio, Roxana; Sant Anna, Hanaisa P.; Santos, Hadassa C.; Duarte, Nubia E.; Fiaccone, Rosemeire L.; Figueiredo, Camila A.; Silva, Thiago M.; Costa, Gustavo N. O.; Beleza, Sandra; Berg, Douglas E.; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H.; Gonçalves, Vanessa F.; Marrero, Andrea R.; Muniz, Yara C.; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C.; Barreto, Mauricio L.; Lima-Costa, M. Fernanda; Pereira, Alexandre C.; Rodrigues, Maíra R.; Tarazona-Santos, Eduardo

    2015-01-01

    While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6–8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes. PMID:26124090

  19. Origin and dynamics of admixture in Brazilians and its effect on the pattern of deleterious mutations.

    PubMed

    Kehdy, Fernanda S G; Gouveia, Mateus H; Machado, Moara; Magalhes, Wagner C S; Horimoto, Andrea R; Horta, Bernardo L; Moreira, Rennan G; Leal, Thiago P; Scliar, Marilia O; Soares-Souza, Giordano B; Rodrigues-Soares, Fernanda; Arajo, Gilderlanio S; Zamudio, Roxana; Sant Anna, Hanaisa P; Santos, Hadassa C; Duarte, Nubia E; Fiaccone, Rosemeire L; Figueiredo, Camila A; Silva, Thiago M; Costa, Gustavo N O; Beleza, Sandra; Berg, Douglas E; Cabrera, Lilia; Debortoli, Guilherme; Duarte, Denise; Ghirotto, Silvia; Gilman, Robert H; Gonalves, Vanessa F; Marrero, Andrea R; Muniz, Yara C; Weissensteiner, Hansi; Yeager, Meredith; Rodrigues, Laura C; Barreto, Mauricio L; Lima-Costa, M Fernanda; Pereira, Alexandre C; Rodrigues, Mara R; Tarazona-Santos, Eduardo

    2015-07-14

    While South Americans are underrepresented in human genomic diversity studies, Brazil has been a classical model for population genetics studies on admixture. We present the results of the EPIGEN Brazil Initiative, the most comprehensive up-to-date genomic analysis of any Latin-American population. A population-based genome-wide analysis of 6,487 individuals was performed in the context of worldwide genomic diversity to elucidate how ancestry, kinship, and inbreeding interact in three populations with different histories from the Northeast (African ancestry: 50%), Southeast, and South (both with European ancestry >70%) of Brazil. We showed that ancestry-positive assortative mating permeated Brazilian history. We traced European ancestry in the Southeast/South to a wider European/Middle Eastern region with respect to the Northeast, where ancestry seems restricted to Iberia. By developing an approximate Bayesian computation framework, we infer more recent European immigration to the Southeast/South than to the Northeast. Also, the observed low Native-American ancestry (6-8%) was mostly introduced in different regions of Brazil soon after the European Conquest. We broadened our understanding of the African diaspora, the major destination of which was Brazil, by revealing that Brazilians display two within-Africa ancestry components: one associated with non-Bantu/western Africans (more evident in the Northeast and African Americans) and one associated with Bantu/eastern Africans (more present in the Southeast/South). Furthermore, the whole-genome analysis of 30 individuals (42-fold deep coverage) shows that continental admixture rather than local post-Columbian history is the main and complex determinant of the individual amount of deleterious genotypes. PMID:26124090

  20. CONTAMINATED SEDIMENTS - ECOLOGICAL EFFECTS RESEARCH

    EPA Science Inventory

    NHEERL's research in this area focuses on ecological effects of bioaccumulative chemicals, such as PCBs. The research is designed with recognition that sites of different size and complexity require bioaccumulation models with correspondingly complex and/or extensive data requir...

  1. 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

  2. Assessing deleterious ecosystem-level effects of environmental pollutants as a means of avoiding evolutionary consequences.

    PubMed Central

    LeBlanc, G A

    1994-01-01

    Recent interest has been expressed in the possible need to develop ways to detect and quantify pollutants that affect evolution. Although environmental pollutants clearly can affect evolutionary processes, the evolutionary changes are a response to ecosystem-level toxicity elicited by the pollutant, rather than a direct effect of the pollutant on evolution. Accordingly, emphasis needs to be placed on assessing the adverse effects of environmental pollutants on ecosystem structure and function in order to avoid subsequent evolutionary consequences. PMID:8033857

  3. 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

  4. 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

  5. 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

  6. Knowledge about the Deleterious Effects of Smoking and Its Relationship to Smoking Cessation among Pregnant Adolescents.

    ERIC Educational Resources Information Center

    Albrecht, Susan A.; Higgins, Linda W.; Lebow, Howard

    2000-01-01

    Examines adolescents' knowledge of the detrimental effects of smoking on pregnant women and fetuses and its relationship to efforts to quit smoking with a sample of pregnant adolescents (N=71). A three-group randomized intervention design -- Teen FreshStart, Teen Freshstart with buddy, and usual care control -- was used. Results show that

  7. 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

  8. 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…

  9. Deleterious effects of soluble amyloid-β oligomers on multiple steps of synaptic vesicle trafficking.

    PubMed

    Park, Joohyun; Jang, Mirye; Chang, Sunghoe

    2013-07-01

    Growing evidence supports a role for soluble amyloid-β oligomer intermediates in the synaptic dysfunction associated with Alzheimer's disease (AD), but the molecular mechanisms underlying this effect remain unclear. We found that acute treatment of cultured rat hippocampal neurons with nanomolar concentrations of Aβ oligomers reduced the recycling pool and increased the resting pool of synaptic vesicles. Endocytosis of synaptic vesicles and the regeneration of fusion-competent vesicles were also severely impaired. Furthermore, the release probability of the readily-releasable pool (RRP) was increased, and recovery of the RRP was delayed. All these effects were prevented by antibody against Aβ. Moreover reduction of the pool size was prevented by inhibiting calpain or CDK5, while the defects in endocytosis were averted by overexpressing phosphatidylinositol-4-phosphate-5-kinase type I-γ, indicating that these two downstream pathways are involved in Aβ oligomers-induced presynaptic dysfunction. PMID:23523634

  10. Feeding on frozen live yeast has some deleterious effects in Drosophila melanogaster.

    PubMed

    Le Bourg, Eric; Gauthier, Tiphaine; Colinet, Herv

    2015-09-01

    Many experiments have shown that dietary restriction, for instance by removing live yeast or modifying the protein/carbohydrate ratio, can modulate lifespan, fecundity, resistance to severe stresses and behaviour in Drosophila melanogaster flies. The present study tested whether feeding flies with frozen yeast rather than with fresh yeast could have some effect on these traits, the other components of the food being similar in the two groups. Freezing altered live yeast quality and flies feeding on frozen yeast lived slightly less (males), were less fecund at older ages, and poorly resisted to some severe stresses (cold and starvation), no negative effect being observed on resistance to heat. It seems that, like in humans, feeding on a low quality food can negatively impact healthspan and that an appropriate food is not only a food with optimal number of calories and appropriate ratios of proteins, carbohydrates, and fat. PMID:26163343

  11. Metabolism of plant polyphenols in the skin: beneficial versus deleterious effects.

    PubMed

    Korkina, Liudmila G; Pastore, Saveria; De Luca, Chiara; Kostyuk, Vladimir A

    2008-10-01

    Polyphenols are produced by all higher plants in order to protect them against biotic and abiotic stress such as UV radiation, temperature changes, infections, wounding, and herbivores. When in contact with human skin, polyphenols exert either curative or damaging action depending on their physical-chemical properties, bioavailability through cutaneous barrier, metabolism in the skin, and individual sensitivity. This review will focus on 1) synthesis and metabolism of polyphenols and their role in the plant physiology, 2) non-enzymatic and enzymatic polyphenol transformation in the skin, 3) polyphenols as inhibitors or inducers of inflammatory response in the skin, and 4) photo-protective versus photo-toxic effects of polyphenols. The potential consequences of these controversial effects on the use of plant polyphenols in dermatology and cosmetology will be also discussed. PMID:18855609

  12. Deleterious effects of a low amount of ethanol on LTP-like plasticity in human cortex.

    PubMed

    Lücke, Caroline; Heidegger, Tonio; Röhner, Mirjam; Toennes, Stefan W; Krivanekova, Lucia; Müller-Dahlhaus, Florian; Ziemann, Ulf

    2014-05-01

    Ingesting ethanol (EtOH) at low doses during social drinking is a common human behavior for its facilitating effects on social interactions. However, low-dose EtOH may have also detrimental effects that so far are underexplored. Here we sought to test the effects of low-dose EtOH on long-term potentiation (LTP)-like plasticity in human motor cortex. Previous cellular experiments showed that low-dose EtOH potentiates extrasynaptic GABAAR and reduces NMDAR-mediated currents, processes that would limit the expression of LTP. Paired associative transcranial magnetic stimulation (PASLTP) was employed in nine healthy subjects for induction of LTP-like plasticity, indexed by a long-term increase in motor-evoked potential input-output curves. Synaptic α1-GABAAR function was measured by saccadic peak velocity (SPV). Very low doses of EtOH (resulting in blood concentrations of <5 mM) suppressed LTP-like plasticity but did not affect SPV when compared with a placebo condition. In contrast, 1 mg of alprazolam, a classical benzodiazepine, or 10 mg of zolpidem, a non-benzodiazepine hypnotic, decreased SPV but did not significantly affect LTP-like plasticity when compared with placebo. This double dissociation of low-dose EtOH vs alprazolam/zolpidem effects is best explained by the putatively high affinity of EtOH but not alprazolam/zolpidem to extrasynaptic GABAARs and to NMDARs. Findings suggest that enhancement of extrasynaptic GABAAR-mediated tonic inhibition and/or reduction of NMDAR-mediated neurotransmission by EtOH blocks LTP-like plasticity in human cortex at very low doses that are easily reached during social drinking. Therefore, low-dose EtOH may jeopardize LTP-dependent processes, such as learning and memory formation. PMID:24385131

  13. Deleterious Effects of a Low Amount of Ethanol on LTP-Like Plasticity in Human Cortex

    PubMed Central

    Lcke, Caroline; Heidegger, Tonio; Rhner, Mirjam; Toennes, Stefan W; Krivanekova, Lucia; Mller-Dahlhaus, Florian; Ziemann, Ulf

    2014-01-01

    Ingesting ethanol (EtOH) at low doses during social drinking is a common human behavior for its facilitating effects on social interactions. However, low-dose EtOH may have also detrimental effects that so far are underexplored. Here we sought to test the effects of low-dose EtOH on long-term potentiation (LTP)-like plasticity in human motor cortex. Previous cellular experiments showed that low-dose EtOH potentiates extrasynaptic GABAAR and reduces NMDAR-mediated currents, processes that would limit the expression of LTP. Paired associative transcranial magnetic stimulation (PASLTP) was employed in nine healthy subjects for induction of LTP-like plasticity, indexed by a long-term increase in motor-evoked potential inputoutput curves. Synaptic ?1-GABAAR function was measured by saccadic peak velocity (SPV). Very low doses of EtOH (resulting in blood concentrations of <5?mM) suppressed LTP-like plasticity but did not affect SPV when compared with a placebo condition. In contrast, 1?mg of alprazolam, a classical benzodiazepine, or 10?mg of zolpidem, a non-benzodiazepine hypnotic, decreased SPV but did not significantly affect LTP-like plasticity when compared with placebo. This double dissociation of low-dose EtOH vs alprazolam/zolpidem effects is best explained by the putatively high affinity of EtOH but not alprazolam/zolpidem to extrasynaptic GABAARs and to NMDARs. Findings suggest that enhancement of extrasynaptic GABAAR-mediated tonic inhibition and/or reduction of NMDAR-mediated neurotransmission by EtOH blocks LTP-like plasticity in human cortex at very low doses that are easily reached during social drinking. Therefore, low-dose EtOH may jeopardize LTP-dependent processes, such as learning and memory formation. PMID:24385131

  14. Liver X receptors interfere with the deleterious effect of diethylstilbestrol on testicular physiology

    SciTech Connect

    Oumeddour, Abdelkader; Viennois, Emilie; Caira, Françoise; Decourbey, Clélia; Maqdasy, Salwan; and others

    2014-04-11

    Highlights: • Part of the neonatal effect of DES on testis needs the presence of Lxrα/β. • Some DES-induced pathways are blocked in Lxr-deficient mice. • Lxr-deficient mice analysis defines DES-target genes protected by Lxr. - Abstract: Liver X receptors LXRα (NR1H3) and LXRβ (NR1H2) are transcription factors belonging to the nuclear receptor superfamily, activated by specific oxysterols, oxidized derivatives of cholesterol. These receptors are involved in the regulation of testis physiology. Lxr-deficient mice pointed to the physiological roles of these nuclear receptors in steroid synthesis, lipid homeostasis and germ cell apoptosis and proliferation. Diethylstilbestrol (DES) is a synthetic estrogen considered as an endocrine disruptor that affects the functions of the testis. Various lines of evidences have made a clear link between estrogens, their nuclear receptors ERα (NR3A1) and ERβ (NR3A2), and Lxrα/β. As LXR activity could also be regulated by the nuclear receptor small heterodimer partner (SHP, NR0A2) and DES could act through SHP, we wondered whether LXR could be targeted by estrogen-like endocrine disruptors such as DES. For that purpose, wild-type and Lxr-deficient mice were daily treated with 0.75 μg DES from days 1 to 5 after birth. The effects of DES were investigated at 10 or 45 days of age. We demonstrated that DES induced a decrease of the body mass at 10 days only in the Lxr-deficient mice suggesting a protective effect of Lxr. We defined three categories of DES-target genes in testis: those whose accumulation is independent of Lxr; those whose accumulation is enhanced by the lack of both Lxrα/β; those whose accumulation is repressed by the absence of Lxrα/β. Lipid accumulation is also modified by neonatal DES injection. Lxr-deficient mice present different lipid profiles, demonstrating that DES could have its effects in part due to Lxrα/β. Altogether, our study shows that both nuclear receptors Lxrα and Lxrβ are not only basally important for testicular physiology but could also have a preventive effect against estrogen-like endocrine disruptors.

  15. Metyrapone Alleviates Deleterious Effects of Maternal Food Restriction on Lung Development and Growth of Rat Offspring

    PubMed Central

    Paek, David S.; Sakurai, Reiko; Saraswat, Aditi; Li, Yishi; Khorram, Omid; Torday, John S.

    2015-01-01

    Maternal food restriction (MFR) causes intrauterine growth restriction, a known risk factor for developing chronic lung disease. However, it is unknown whether this negative outcome is gender specific or preventable by blocking the MFR-induced hyperglucocorticoidism. Using a well-established rat model, we used metyrapone (MTP), an inhibitor of glucocorticoid synthesis, to study the MFR-induced lung changes on postnatal day (p) 21 in a gender-specific manner. From embryonic day 10 until delivery, pregnant dams were fed either an ad libitum diet or a 50% caloric restricted diet with or without MTP supplementation. Postnatally, the offspring were fed ad libitum from healthy dams until p21. Morphometric, Western blot, and immunohistochemical analysis of the lungs demonstrated that MTP mitigated the MFR-mediated decrease in alveolar count, decrease in adipogenic protein peroxisome proliferator-activated receptor γ, increase in myogenic proteins (fibronectin, α-smooth muscle actin, and calponin), increase in Wnt signaling intermediates (lymphoid enhancer-binding factor 1 and β-catenin), and increase in glucocorticoid receptor (GR) levels. The MFR-induced lung phenotype and the effects of MTP were similar in both genders. To elucidate the mechanism of MFR-induced shift of the adipogenic-to-myogenic phenotype, lung fibroblasts were used to independently study the effects of (1) nutrient restriction and (2) excess steroid exposure. Nutrient deprivation increased myogenic proteins, Wnt signaling intermediates, and GR, all changes blocked by protein supplementation. MTP also blocked, likely by normalizing nicotinamide adenine dinucleotide phosphate levels, the corticosterone-induced increase in myogenic proteins, but had no effect on GR levels. In summary, protein restriction and increased glucocorticoid levels appear to be the key players in MFR-induced lung disease, affecting both genders. PMID:24916330

  16. Metyrapone alleviates deleterious effects of maternal food restriction on lung development and growth of rat offspring.

    PubMed

    Paek, David S; Sakurai, Reiko; Saraswat, Aditi; Li, Yishi; Khorram, Omid; Torday, John S; Rehan, Virender K

    2015-02-01

    Maternal food restriction (MFR) causes intrauterine growth restriction, a known risk factor for developing chronic lung disease. However, it is unknown whether this negative outcome is gender specific or preventable by blocking the MFR-induced hyperglucocorticoidism. Using a well-established rat model, we used metyrapone (MTP), an inhibitor of glucocorticoid synthesis, to study the MFR-induced lung changes on postnatal day (p) 21 in a gender-specific manner. From embryonic day 10 until delivery, pregnant dams were fed either an ad libitum diet or a 50% caloric restricted diet with or without MTP supplementation. Postnatally, the offspring were fed ad libitum from healthy dams until p21. Morphometric, Western blot, and immunohistochemical analysis of the lungs demonstrated that MTP mitigated the MFR-mediated decrease in alveolar count, decrease in adipogenic protein peroxisome proliferator-activated receptor ?, increase in myogenic proteins (fibronectin, ?-smooth muscle actin, and calponin), increase in Wnt signaling intermediates (lymphoid enhancer-binding factor 1 and ?-catenin), and increase in glucocorticoid receptor (GR) levels. The MFR-induced lung phenotype and the effects of MTP were similar in both genders. To elucidate the mechanism of MFR-induced shift of the adipogenic-to-myogenic phenotype, lung fibroblasts were used to independently study the effects of (1) nutrient restriction and (2) excess steroid exposure. Nutrient deprivation increased myogenic proteins, Wnt signaling intermediates, and GR, all changes blocked by protein supplementation. MTP also blocked, likely by normalizing nicotinamide adenine dinucleotide phosphate levels, the corticosterone-induced increase in myogenic proteins, but had no effect on GR levels. In summary, protein restriction and increased glucocorticoid levels appear to be the key players in MFR-induced lung disease, affecting both genders. PMID:24916330

  17. 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

  18. Deleterious effects of endotoxin on cultured endothelial cells: an in vitro model of vascular injury

    SciTech Connect

    Yamada, O.; Moldow, C.F.; Sacks, T.; Craddock, P.R.; Boogaerts, M.A.; Jacob, H.S.

    1981-06-01

    The effects of endotoxin-triggered granulocytes on the viability of endothelial cells in vitro was investigated. Endotoxin or its lipid A component caused granulocytes to adhere to and significantly damage cultured endothelial cells. Fresh serum is not necessary but does amplify both adherence and endothelial injury. Much of the endothelial injury was inhibited by free-radical scavengers or by blocking granulocyte adhesion to endothelial cells and appears to result from free radical production by the stimulated granulocyte. Studies in this model suggest a pathogenic role for the endotoxin-triggered granulocyte in the Shwartzman reaction and perhaps related clinical disorders.

  19. 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

  20. Estimation of deleterious genomic mutation parameters in natural populations by accounting for variable mutation effects across loci.

    PubMed Central

    Deng, Hong-Wen; Gao, Guimin; Li, Jin-Long

    2002-01-01

    The genomes of all organisms are subject to continuous bombardment of deleterious genomic mutations (DGM). Our ability to accurately estimate various parameters of DGM has profound significance in population and evolutionary genetics. The Deng-Lynch method can estimate the parameters of DGM in natural selfing and outcrossing populations. This method assumes constant fitness effects of DGM and hence is biased under variable fitness effects of DGM. Here, we develop a statistical method to estimate DGM parameters by considering variable mutation effects across loci. Under variable mutation effects, the mean fitness and genetic variance for fitness of parental and progeny generations across selfing/outcrossing in outcrossing/selfing populations and the covariance between mean fitness of parents and that of their progeny are functions of DGM parameters: the genomic mutation rate U, average homozygous effect s, average dominance coefficient h, and covariance of selection and dominance coefficients cov(h, s). The DGM parameters can be estimated by the algorithms we developed herein, which may yield improved estimation of DGM parameters over the Deng-Lynch method as demonstrated by our simulation studies. Importantly, this method is the first one to characterize cov(h, s) for DGM. PMID:12454090

  1. 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

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

    PubMed

    Delgado-Corts, Mara Jos; Espinosa-Oliva, Ana M; Sarmiento, Manuel; Argelles, Sandro; Herrera, Antonio J; Maurio, Raquel; Villarn, Ruth F; Venero, Jos L; Machado, Alberto; de Pablos, Roco 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

  3. Acetaldehyde content and oxidative stress in the deleterious effects of alcohol drinking on rat uterine horn.

    PubMed

    Buthet, Lara Romina; Maciel, Mara Eugenia; Quintans, Leandro Nstor; Rodrguez de Castro, Carmen; Costantini, Martn Hernn; Fanelli, Silvia Laura; Castro, Jos Alberto; Castro, Gerardo Daniel

    2013-01-01

    After alcohol exposure through a standard Lieber and De Carli diet for 28 days, a severe atrophy in the rat uteirne horn was observed, accompanied by significant alterations in its epithelial cells. Microsomal pathway of acetaldehyde production was slightly increased. Hydroxyl radicals were detected in the cytosolic fraction, and this was attributed to participation of xanthine oxidoreductase. They were also observed in the microsomal fraction in the presence of NADPH generating system. No generation of 1-hydroxyethyl was evidenced. The t-butylhydroperoxide-induced chemiluminescence analysis of uterine horn homogenates revealed a significant increase in the chemiluminiscence emission due to ethanol exposure. In the animals repeatedly exposed to alcohol, sulfhydryl content from uterine horn proteins was decreased, but no significant changes were observed in the protein carbonyl content from the same samples. Minor but significant decreasing changes were observed in the GSH content accompanied by a tendency to decrease in the GSH/GSSG ratio. A highly significant finding was the diminished activity content of glutathione peroxidase. Results suggest that acetaldehyde accumulation plus the oxidative stress may play an additional effect to the alcohol-promoted hormonal changes in the uterus reported by others after chronic exposure to alcohol. PMID:24348548

  4. Acetaldehyde Content and Oxidative Stress in the Deleterious Effects of Alcohol Drinking on Rat Uterine Horn

    PubMed Central

    Buthet, Lara Romina; Maciel, Mara Eugenia; Quintans, Leandro Nstor; Rodrguez de Castro, Carmen; Costantini, Martn Hernn; Castro, Jos Alberto

    2013-01-01

    After alcohol exposure through a standard Lieber and De Carli diet for 28 days, a severe atrophy in the rat uteirne horn was observed, accompanied by significant alterations in its epithelial cells. Microsomal pathway of acetaldehyde production was slightly increased. Hydroxyl radicals were detected in the cytosolic fraction, and this was attributed to participation of xanthine oxidoreductase. They were also observed in the microsomal fraction in the presence of NADPH generating system. No generation of 1-hydroxyethyl was evidenced. The t-butylhydroperoxide-induced chemiluminescence analysis of uterine horn homogenates revealed a significant increase in the chemiluminiscence emission due to ethanol exposure. In the animals repeatedly exposed to alcohol, sulfhydryl content from uterine horn proteins was decreased, but no significant changes were observed in the protein carbonyl content from the same samples. Minor but significant decreasing changes were observed in the GSH content accompanied by a tendency to decrease in the GSH/GSSG ratio. A highly significant finding was the diminished activity content of glutathione peroxidase. Results suggest that acetaldehyde accumulation plus the oxidative stress may play an additional effect to the alcohol-promoted hormonal changes in the uterus reported by others after chronic exposure to alcohol. PMID:24348548

  5. Exposure to prenatal stress has deleterious effects on hippocampal function in a febrile seizure rat model.

    PubMed

    Qulu, Lihle; Daniels, W M U; Mabandla, Musa V

    2015-10-22

    Prenatal stress has been shown to result in the development of a number of neurological disorders in the offspring. Most of these disorders are a result of an altered HPA axis resulting in higher than normal glucocorticoid levels in the affected neonate. This leaves the offspring prone to immune challenges. Therefore the aim of the present study was to investigate the effects of prenatal stress and febrile seizures on behavior and hippocampal function. Pregnant dams were exposed to restraint stress during the third trimester. Following birth, febrile seizures were induced in two week old pups using lipopolysaccharide and kainic acid. A week later, anxiety-like behavior and navigational ability was assessed. Trunk blood was used to measure basal corticosterone concentration and hippocampal tissue was collected and analyzed. Our results show that exposure to prenatal stress increased basal corticosterone concentration. Exposure to prenatal stress exacerbated anxiety-like behavior and impaired the rat's navigational ability. Exposure to prenatal stress resulted in reduced hippocampal mass that was exacerbated by febrile seizures. However, exposure to febrile seizures did not affect hippocampal mass in the absence of prenatal stress. This suggests that febrile seizures are exacerbated by exposure to early life stressors and this may lead to the development of neurological symptoms associated with a malfunctioning hippocampus. PMID:26256254

  6. Antimicrobial photodynamic therapy minimizes the deleterious effect of nicotine in female rats with induced periodontitis.

    PubMed

    Gualberto, Erivan Clementino; Theodoro, Letcia Helena; Longo, Marielln; Novaes, Vivian Cristina Noronha; Nagata, Maria Jos Hitomi; Ervolino, Edilson; Garcia, Valdir Gouveia

    2016-01-01

    The aim of this study was to compare the use of antimicrobial photodynamic therapy (aPDT) as an adjunct to scaling and root planing (SRP) in the treatment of experimentally induced periodontitis in female rats that were systemically treated with or without nicotine. Female rats (n?=?180) were divided into two groups: vehicle administration (Veh) and nicotine administration (Nic). Mini-pumps containing either vehicle or nicotine were implanted in the rats 30days before the induction of experimental periodontitis (EP). EP was induced by placing a cotton ligature around the left mandibular first molar. After 7days, the ligature was removed, and the rats were randomly divided into three treatment subgroups: SRP (only SRP), DL (SRP plus diode laser), and aPDT (SRP plus aPDT). The aPDT consisted of phenothiazine photosensitizer deposition followed by diode laser irradiation. Ten rats from each subgroup were euthanized at 7, 15, and 30days after treatment. Alveolar bone loss (ABL) in the furcation region was evaluated using histological, histometric, and immunohistochemical analyses. The rats that were treated with nicotine showed more ABL compared to those treated with vehicle. In both the Veh and Nic groups, SRP plus aPDT treatment resulted in reduced ABL, smaller numbers of both TRAP- and RANKL-positive cells, and higher numbers of PCNA-positive cells compared to SRP treatment alone. aPDT was an effective adjunctive therapy for the treatment of periodontitis in female rats regardless of whether they received nicotine. PMID:26545755

  7. Deleterious effect of oltipraz on extrahepatic cholestasis in bile duct-ligated mice

    PubMed Central

    Weerachayaphorn, Jittima; Luo, Yuhuan; Mennone, Albert; Soroka, Carol J.; Harry, Kathy; Boyer, James L.

    2014-01-01

    Background & Aims Oltipraz (4-methyl-5(pyrazinyl-2)-1-2-dithiole-3-thione), a promising cancer preventive agent, has an anti-oxidative activity and ability to enhance glutathione biosynthesis, phase II detoxification enzymes and multidrug resistance-associated protein-mediated efflux transporters. Oltipraz can protect against hepatotoxicity caused by carbon tetrachloride, acetaminophen and alpha-naphthylisothiocyanate. Whether oltipraz has hepato-protective effects on obstructive cholestasis is unknown. Methods We administered oltipraz to mice for 5 days prior to bile duct ligation (BDL) for 3 days. Liver histology, liver function markers, bile flow rates and hepatic expression of profibrogenic genes were evaluated. Results Mice pretreated with oltipraz prior to BDL demonstrated higher levels of serum aminotransferases and more severe liver damage than in control mice. Higher bile flow and glutathione secretion rates were observed in unoperated mice treated with oltipraz than in control mice, suggesting that liver necrosis in oltipraz-treated BDL mice may be related partially to increased bile-acid independent flow and biliary pressure. Oltipraz treatment in BDL mice enhanced -smooth muscle actin expression, consistent with activation of hepatic stellate cells and portal fibroblasts. Matrix metalloproteinases (MMP) 9 and 13 and tissue inhibitors of metalloproteinases (TIMP) 1 and 2 levels were increased in the oltipraz -treated BDL group, suggesting that the secondary phase of liver injury induced by oltipraz might be due to excessive MMP and TIMP secretions which induce remodeling of the extracellular matrix. Conclusions Oltipraz treatment exacerbates the severity of liver injury following BDL and should be avoided as therapy for extrahepatic cholestatic disorders due to bile duct obstruction. PMID:23978715

  8. Deleterious effects of plant cystatins against the banana weevil Cosmopolites sordidus.

    PubMed

    Kiggundu, Andrew; Muchwezi, Josephine; Van der Vyver, Christell; Viljoen, Altus; Vorster, Juan; Schlüter, Urte; Kunert, Karl; Michaud, Dominique

    2010-02-01

    The general potential of plant cystatins for the development of insect-resistant transgenic plants still remains to be established given the natural ability of several insects to compensate for the loss of digestive cysteine protease activities. Here we assessed the potential of cystatins for the development of banana lines resistant to the banana weevil Cosmopolites sordidus, a major pest of banana and plantain in Africa. Protease inhibitory assays were conducted with protein and methylcoumarin (MCA) peptide substrates to measure the inhibitory efficiency of different cystatins in vitro, followed by a diet assay with cystatin-infiltrated banana stem disks to monitor the impact of two plant cystatins, oryzacystatin I (OC-I, or OsCYS1) and papaya cystatin (CpCYS1), on the overall growth rate of weevil larvae. As observed earlier for other Coleoptera, banana weevils produce a variety of proteases for dietary protein digestion, including in particular Z-Phe-Arg-MCA-hydrolyzing (cathepsin L-like) and Z-Arg-Arg-MCA-hydrolyzing (cathepsin B-like) proteases active in mildly acidic conditions. Both enzyme populations were sensitive to the cysteine protease inhibitor E-64 and to different plant cystatins including OsCYS1. In line with the broad inhibitory effects of cystatins, OsCYS1 and CpCYS1 caused an important growth delay in young larvae developing for 10 days in cystatin-infiltrated banana stem disks. These promising results, which illustrate the susceptibility of C. sordidus to plant cystatins, are discussed in the light of recent hypotheses suggesting a key role for cathepsin B-like enzymes as a determinant for resistance or susceptibility to plant cystatins in Coleoptera. PMID:20035549

  9. Cooling dialysate during in-center hemodialysis: Beneficial and deleterious effects.

    PubMed

    Toth-Manikowski, Stephanie M; Sozio, Stephen M

    2016-03-01

    The use of cooled dialysate temperatures first came about in the early 1980s as a way to curb the incidence of intradialytic hypotension (IDH). IDH was then, and it remains today, the most common complication affecting chronic hemodialysis patients. It decreases quality of life on dialysis and is an independent risk factor for mortality. Cooling dialysate was first employed as a technique to incite peripheral vasoconstriction on dialysis and in turn reduce the incidence of intradialytic hypotension. Although it has become a common practice amongst in-center hemodialysis units, cooled dialysate results in up to 70% of patients feeling cold while on dialysis and some even experience shivering. Over the years, various studies have been performed to evaluate the safety and efficacy of cooled dialysate in comparison to a standard, more thermoneutral dialysate temperature of 37 °C. Although these studies are limited by small sample size, they are promising in many aspects. They demonstrated that cooled dialysis is safe and equally efficacious as thermoneutral dialysis. Although patients report feeling cold on dialysis, they also report increased energy and an improvement in their overall health following cooled dialysis. They established that cooling dialysate temperatures improves hemodynamic tolerability during and after hemodialysis, even in patients prone to IDH, and does so without adversely affecting dialysis adequacy. Cooled dialysis also reduces the incidence of IDH and has a protective effect over major organs including the heart and brain. Finally, it is an inexpensive measure that decreases economic burden by reducing necessary nursing intervention for issues that arise on hemodialysis such as IDH. Before cooled dialysate becomes standard of care for patients on chronic hemodialysis, larger studies with longer follow-up periods will need to take place to confirm the encouraging outcomes mentioned here. PMID:26981441

  10. A new approach to tag design in dolphin telemetry: Computer simulations to minimise deleterious effects

    NASA Astrophysics Data System (ADS)

    Pavlov, V. V.; Wilson, R. P.; Lucke, K.

    2007-02-01

    Remote-sensors and transmitters are powerful devices for studying cetaceans at sea. However, despite substantial progress in microelectronics and miniaturisation of systems, dolphin tags are imperfectly designed; additional drag from tags increases swim costs, compromises swimming capacity and manoeuvrability, and leads to extra loads on the animal's tissue. We propose a new approach to tag design, elaborating basic principles and incorporating design stages to minimise device effects by using computer-aided design. Initially, the operational conditions of the device are defined by quantifying the shape, hydrodynamics and range of the natural deformation of the dolphin body at the tag attachment site (such as close to the dorsal fin). Then, parametric models of both of the dorsal fin and a tag are created using the derived data. The link between parameters of the fin and a tag model allows redesign of tag models according to expected changes of fin geometry (difference in fin shape related with species, sex, and age peculiarities, simulation of the bend of the fin during manoeuvres). A final virtual modelling stage uses iterative improvement of a tag model in a computer fluid dynamics (CFD) environment to enhance tag performance. This new method is considered as a suitable tool of tag design before creation of the physical model of a tag and testing with conventional wind/water tunnel technique. Ultimately, tag materials are selected to conform to the conditions identified by the modelling process and thus help create a physical model of a tag, which should minimise its impact on the animal carrier and thus increase the reliability and quality of the data obtained.

  11. Deleterious effects of obesity on physical fitness in pre-pubertal children.

    PubMed

    Ceschia, Arianna; Giacomini, Stefano; Santarossa, Simone; Rugo, Miriam; Salvadego, Desy; Da Ponte, Alessandro; Driussi, Caterina; Mihaleje, Martina; Poser, Stefano; Lazzer, Stefano

    2016-03-01

    The prevalence of obesity in children has increased dramatically during the past decades in Europe and understanding physical fitness and its components in children is critical to design and implement effective interventions. The objective of the present study was to analyse the association between physical fitness (aerobic, speed, agility, power, flexibility and balance) and body mass index (BMI) in pre-pubertal children. A total of 2411 healthy schoolchildren (7-11 years) participated in this study. Anthropometric characteristics and body composition were assessed by skinfold thickness. Physical fitness was measured by nine physical fitness tests: endurance running, 20 m running speed, agility, handgrip strength, standing long jump and squat jump, sit and reach, medicine ball forward throw and static balance. No relevant differences were observed between boys and girls regarding anthropometric characteristics, body composition and physical fitness. However, overweight and obese children showed significantly lower physical fitness levels in endurance running, speed and agility (mean: +18.8, +5.5 and +14.5% of time to complete tasks, respectively), lower limb power normalised to body mass (-23.3%) and balance tests (number of falls: +165.5%) than their normal weight counterparts. On the other hand, obesity did not affect handgrip, throwing and flexibility. In conclusion, increased BMI was associated with lower performance capabilities limiting proper motor skill development, which directly affects the ability of children to take on sports skills. Actions undertaken to promote children's wellness and fitness should be prioritised and introduced early in life with the aim of enhancing physical fitness as well as preventing overweight and obesity. PMID:25866877

  12. Cooling dialysate during in-center hemodialysis: Beneficial and deleterious effects

    PubMed Central

    Toth-Manikowski, Stephanie M; Sozio, Stephen M

    2016-01-01

    The use of cooled dialysate temperatures first came about in the early 1980s as a way to curb the incidence of intradialytic hypotension (IDH). IDH was then, and it remains today, the most common complication affecting chronic hemodialysis patients. It decreases quality of life on dialysis and is an independent risk factor for mortality. Cooling dialysate was first employed as a technique to incite peripheral vasoconstriction on dialysis and in turn reduce the incidence of intradialytic hypotension. Although it has become a common practice amongst in-center hemodialysis units, cooled dialysate results in up to 70% of patients feeling cold while on dialysis and some even experience shivering. Over the years, various studies have been performed to evaluate the safety and efficacy of cooled dialysate in comparison to a standard, more thermoneutral dialysate temperature of 37 °C. Although these studies are limited by small sample size, they are promising in many aspects. They demonstrated that cooled dialysis is safe and equally efficacious as thermoneutral dialysis. Although patients report feeling cold on dialysis, they also report increased energy and an improvement in their overall health following cooled dialysis. They established that cooling dialysate temperatures improves hemodynamic tolerability during and after hemodialysis, even in patients prone to IDH, and does so without adversely affecting dialysis adequacy. Cooled dialysis also reduces the incidence of IDH and has a protective effect over major organs including the heart and brain. Finally, it is an inexpensive measure that decreases economic burden by reducing necessary nursing intervention for issues that arise on hemodialysis such as IDH. Before cooled dialysate becomes standard of care for patients on chronic hemodialysis, larger studies with longer follow-up periods will need to take place to confirm the encouraging outcomes mentioned here. PMID:26981441

  13. Reversing the deleterious effects of aging on neuronal communication and behavior: beneficial properties of fruit polyphenolic compounds.

    PubMed

    Joseph, James A; Shukitt-Hale, Barbara; Casadesus, Gemma

    2005-01-01

    Despite elegant research involving molecular biology studies and determination of the genetic mechanisms of aging, practical information on how to forestall or reverse the deleterious effects of aging may be years away. If this is the case, then it is prudent to try to establish other methods that can be used now to alter the course of aging. Numerous epidemiologic studies have indicated that individuals who consume diets containing large amounts of fruits and vegetables may reduce their risk for developing age-related diseases such as Alzheimer disease. Research from our laboratory suggested that dietary supplementation with fruit or vegetable extracts high in antioxidants (eg, blueberry or spinach extracts) might decrease the enhanced vulnerability to oxidative stress that occurs in aging. These reductions might be expressed as improvements in motor and cognitive behavior. Additional research suggested that mechanisms in addition to antioxidant and antiinflammatory activities might be involved in the beneficial effects of these extracts; the most important of these might be their ability to increase cellular signaling and neuronal communication. PMID:15640496

  14. [Reduction of a risk of the deleterious effects of persistent toxic substances on the health of the far north population].

    PubMed

    Dudarev, A A; Mizerniuk, V N; Chupakhin, V S; Lebedev, G B; Chashchin, V P

    2010-01-01

    The paper presents the general principles and procedure of the development and implementation of measures to decrease and prevent environmental pollution with persistent toxic substances (PTS) in the Russian Arctic and, accordingly, to reduce a risk of the deleterious effects of PTS on human health. Based on the results of a study of PTS in the Russian Arctic (from the Kola Peninsula to Chukotka), the authors first systematized the basic lines and actions and formulated specific measures to reduce the North population's exposure to PTSs, such as polychlorinated biphenyls, organic chlorine pesticides (dichlorodiphenyltrichloroethane, hexachlorocyclohexane, hexachlorobenzene, etc.), and heavy metals (mercury, lead, cadmium). A package of measures is aimed at maximally reducing the presence of PTS-containing objects and materials in the north (via detection, collection, and extermination), at neutralizing the soils in settlement lands, at setting up safe water consumption systems, at organizing effective control over the safe use of chemicals and the levels of PTS in raw food materials and foodstuffs, and at working out recommendations on safe procedures for food purchase, storage, and cooking. PMID:20491265

  15. Fructooligosaccharides enhance mineral apparent absorption and counteract the deleterious effects of phytic acid on mineral homeostasis in rats.

    PubMed

    Lopez, H W; Coudray, C; Levrat-Verny, M A; Feillet-Coudray, C; Demign, C; Rmsy, C

    2000-10-01

    Phytic acid (PA) and fructooligosaccharides (FOS) such as inulin are two food components that are able to modify mineral absorption negatively or positively. The influence of PA and FOS on the cecal and apparent mineral absorption as well as on the mineral status (plasma, hepatic, and bone) were investigated in four groups of rats fed one of the experimental diets: a fiber-free (FF) diet, a FF diet containing 7 g/kg PA (FF + PA), a diet containing 100 g/kg inulin (FOS), or a FOS diet containing 7 g/kg PA (FOS + PA). The cecal enlargement together with the acidification of cecal pH in rats adapted to FOS diets led to an improved Ca and Mg cecal absorption. Mineral apparent absorption was significantly enhanced by FOS ingestion (Ca, +20%; Mg, +50%; Fe, +23%; Cu, +45%), whereas PA decreased this factor only for trace elements (Fe, -48%; Zn, -62%; Cu, -31%). These inhibitory effects of a FF + PA diet have repercussions on blood (Mg, -15%; Fe, -12%; transferrin saturation -31%), liver (Mg, -18%; Fe, -42%; Zn, -25%), and bone (Zn, -25%) variables. However, the introduction of FOS into a PA diet counteracted these observed deleterious effects by stimulating bacterial hydrolysis of PA (+60% in rats adapted to FOS + PA compared to those fed the FF + PA diet) and by improving cecal absorption of minerals. PMID:11120448

  16. Deleterious effects of sunscreen titanium dioxide nanoparticles on DNA: efforts to limit DNA damage by particle surface modification

    NASA Astrophysics Data System (ADS)

    Serpone, Nick; Salinaro, Angela; Emeline, A.

    2001-06-01

    Sunlight can have deleterious effects on humans: causes sunburns and is the principal cause of skin cancers. Usage of TiO2 (and ZnO) in sunscreen lotions, widely used as UVA/UVB blockers, and intended to prevent sunburns and to protect consumers from skin cancers (carcinomas and melanomas) is examined. Although used to mineralize many undesired organic pollutants, TiO2 is considered to be a safe physical sunscreen agent because it reflects and scatters both UVB (290-320 nm) and UVA (320-400 nm) sunlight; however, it also absorbs substantial UV radiation which, in aqueous media, yields hydroxyl radial ((DOT)OH) species. These species cause substantial damage to DNA (J. Photochem.Photobio.A:Chem.,111(1997)205). Most importantly, sunlight-illuminated sunscreen TiO2 particles catalyze DNA damage both in vitro and in human cells (FEBS Letters, 418 (1997)87). These results raise concerns on the overall effects of sunscreens and raise the question on the suitability of photoactive TiO2 as a sunscreen component without further studies. The photocatalytically active nature of these metal oxides necessitates some changes since even the TiO2 specimens currently used in suncreams cause significant DNA strand breaks.

  17. Activators of the Glutamate-Dependent Acid Resistance System Alleviate Deleterious Effects of YidC Depletion in Escherichia coli?

    PubMed Central

    Yu, Zhong; Bekker, Martijn; Tramonti, Angela; Cook, Gregory M.; van Ulsen, Peter; Scheffers, Dirk-Jan; de Mattos, Joost Teixeira; De Biase, Daniela; Luirink, Joen

    2011-01-01

    The function of the essential inner membrane protein (IMP) YidC in Escherichia coli has been studied for a limited number of model IMPs and primarily using targeted approaches. These studies suggested that YidC acts at the level of insertion, folding, and quality control of IMPs, both in the context of the Sec translocon and as a separate entity. To further our understanding of YidC's role in IMP biogenesis, we screened a random overexpression library for factors that rescued the growth of cells upon YidC depletion. We found that the overexpression of the GadX and GadY regulators of the glutamate-dependent acid resistance system complemented the growth defect of YidC-depleted cells. Evidence is presented that GadXY overexpression counteracts the deleterious effects of YidC depletion on at least two fronts. First, GadXY prepares the cells for the decrease in respiratory capacity upon the depletion of YidC. Most likely, GadXY-regulated processes reduce the drop in proton-motive force that impairs the fitness of YidC-depleted cells. Second, in GadXY-overproducing cells increased levels of the general chaperone GroEL cofractionate with the inner membranes, which may help to keep newly synthesized inner membrane proteins in an insertion-competent state when YidC levels are limiting. PMID:21216990

  18. Effect of selection against deleterious mutations on the decline in heterozygosity at neutral loci in closely inbreeding populations.

    PubMed Central

    Wang, J; Hill, W G

    1999-01-01

    Transition matrices for selfing and full-sib mating were derived to investigate the effect of selection against deleterious mutations on the process of inbreeding at a linked neutral locus. Selection was allowed to act within lines only (selection type I) or equally within and between lines (type II). For selfing lines under selection type I, inbreeding is always retarded, the retardation being determined by the recombination fraction between the neutral and selected loci and the inbreeding depression from the selected locus, irrespective of the selection coefficient (s) and dominance coefficient (h) of the mutant allele. For selfing under selection type II or full-sib mating under both selection types, inbreeding is delayed by weak selection (small s and sh), due to the associative overdominance created at the neutral locus, and accelerated by strong selection, due to the elevated differential contributions between alternative alleles at the neutral locus within individuals and between lines (for selection type II). For multiple fitness loci under selection, stochastic simulations were run for populations with selfing, full-sib mating, and random mating, using empirical estimates of mutation parameters and inbreeding load in Drosophila. The simulations results are in general compatible with empirical observations. PMID:10545475

  19. 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

  20. C5aR-antagonist significantly reduces the deleterious effect of a blunt chest trauma on fracture healing

    PubMed Central

    Recknagel, Stefan; Bindl, Ronny; Kurz, Julian; Wehner, Tim; Schngraf, Phillip; Ehrnthaller, Christian; Qu, Hongchang; Gebhard, Florian; Huber-Lang, Markus; Lambris, John D.; Claes, Lutz; Ignatius, Anita

    2011-01-01

    Confirming clinical evidence, we recently demonstrated that a blunt chest trauma considerably impaired fracture healing in rats, possibly via the interaction of posttraumatic systemic inflammation with local healing processes, the underlying mechanisms being unknown. An important trigger of systemic inflammation is the complement system, with the potent anaphylatoxin C5a. Therefore, we investigated whether the impairment of fracture healing by a severe trauma resulted from systemically activated complement. Rats received a blunt chest trauma and a femur osteotomy stabilized with an external fixator. To inhibit the C5a dependent posttraumatic systemic inflammation, half of the rats received a C5aR-antagonist intravenously immediately and 12 h after the thoracic trauma. Compared to the controls (control peptide), the treatment with the C5aR-antagonist led to a significantly increased flexural rigidity (three-point-bending test), an improved bony bridging of the fracture gap, and a slightly larger and qualitatively improved callus (?CT, histomorphometry) after 35 days. In conclusion, immunomodulation by a C5aR-antagonist could abolish the deleterious effects of a thoracic trauma on fracture healing, possibly by influencing the function of inflammatory and bone cells locally at the fracture site. C5a could possibly represent a target to prevent delayed bone healing in patients with severe trauma. PMID:21922535

  1. 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; Gusmo, Emeline Pereira; Moreira, Cau Bonucci; Romano, Luis Alberto; Sampaio, Lus Andr

    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

  2. Overexpression of Human and Fly Frataxins in Drosophila Provokes Deleterious Effects at Biochemical, Physiological and Developmental Levels

    PubMed Central

    Soriano, Sirena; Botella, Jos A.; Schneuwly, Stephan; Martnez-Sebastin, Mara J.; Molt, Mara D.

    2011-01-01

    Background Friedreich's ataxia (FA), the most frequent form of inherited ataxias in the Caucasian population, is caused by a reduced expression of frataxin, a highly conserved protein. Model organisms have contributed greatly in the efforts to decipher the function of frataxin; however, the precise function of this protein remains elusive. Overexpression studies are a useful approach to investigate the mechanistic actions of frataxin; however, the existing literature reports contradictory results. To further investigate the effect of frataxin overexpression, we analyzed the consequences of overexpressing human (FXN) and fly (FH) frataxins in Drosophila. Methodology/Principal Findings We obtained transgenic flies that overexpressed human or fly frataxins in a general pattern and in different tissues using the UAS-GAL4 system. For both frataxins, we observed deleterious effects at the biochemical, histological and behavioral levels. Oxidative stress is a relevant factor in the frataxin overexpression phenotypes. Systemic frataxin overexpression reduces Drosophila viability and impairs the normal embryonic development of muscle and the peripheral nervous system. A reduction in the level of aconitase activity and a decrease in the level of NDUF3 were also observed in the transgenic flies that overexpressed frataxin. Frataxin overexpression in the nervous system reduces life span, impairs locomotor ability and causes brain degeneration. Frataxin aggregation and a misfolding of this protein have been shown not to be the mechanism that is responsible for the phenotypes that have been observed. Nevertheless, the expression of human frataxin rescues the aconitase activity in the fh knockdown mutant. Conclusion/Significance Our results provide in vivo evidence of a functional equivalence for human and fly frataxins and indicate that the control of frataxin expression is important for treatments that aim to increase frataxin levels. PMID:21779322

  3. Imipramine protects against the deleterious effects of chronic corticosterone on depression-like behavior, hippocampal reelin expression, and neuronal maturation.

    PubMed

    Fenton, Erin Y; Fournier, Neil M; Lussier, April L; Romay-Tallon, Raquel; Caruncho, Hector J; Kalynchuk, Lisa E

    2015-07-01

    We have hypothesized that a downregulation of reelin and deficient maturation of adult-born hippocampal neurons are important factors in the pathogenesis of depression. This hypothesis is based on previous work showing that depression-like behavior in rats treated with protracted corticosterone develops in concert with decreased dendritic complexity in newborn hippocampal granule neurons and decreased reelin expression in the proliferative subgranular zone of the dentate gyrus. In addition, heterozygous reeler mice with approximately 50% of normal brain levels of reelin are more vulnerable to the depressogenic effects of corticosterone than wild-type mice. The purpose of this experiment was to provide pharmacological validation for the link between reelin, neuronal maturation, and depression by examining whether the deleterious effects of corticosterone on these measures could be prevented by co-administration of the antidepressant imipramine. Rats received corticosterone injections, corticosterone injections plus either 10 or 15mg/kg imipramine injections, or vehicle injections for 21 consecutive days. They were then subjected to the forced swim test to assess depression-like behavior and sacrificed for immunohistochemical examination of immature neuron number and dendritic complexity and the presence of reelin+cells. We found that corticosterone increases depression-like behavior, decreases the number of reelin+cells in the subgranular zone, and decreases the number and complexity of immature neurons in the granule cell layer. All of these behavioral and cellular phenotypes were prevented by imipramine, providing further support for the idea that reelin is involved in the pathogenesis of depression. PMID:25681757

  4. 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

  5. Deleterious effects of freezing on osteogenic differentiation of human adipose-derived stromal cells in vitro and in vivo.

    PubMed

    James, Aaron W; Levi, Benjamin; Nelson, Emily R; Peng, Michelle; Commons, George W; Lee, Min; Wu, Benjamin; Longaker, Michael T

    2011-03-01

    Human adipose-derived stromal cells (hASCs) represent a multipotent stromal cell type with a proven capacity to undergo osteogenic differentiation. Many hurdles exist, however, between current knowledge of hASC osteogenesis and their potential future use in skeletal tissue regeneration. The impact of frozen storage on hASC osteogenic differentiation, for example, has not been studied in detail. To examine the effects of frozen storage, hASCs were harvested from lipoaspirate and either maintained in standard culture conditions or frozen for 2 weeks under standard conditions (90% fetal bovine serum, 10% dimethyl sulfoxide). Next, in vitro parameters of cell morphology (surface electron microscopy [EM]), cell viability and growth (trypan blue; bromodeoxyuridine incorporation), osteogenic differentiation (alkaline phosphatase, alizarin red, and quantitative real-time (RT)-polymerase chain reaction), and adipogenic differentiation (Oil red O staining and quantitative RT-polymerase chain reaction) were performed. Finally, in vivo bone formation was assessed using a critical-sized cranial defect in athymic mice, utilizing a hydroxyapatite (HA)-poly(lactic-co-glycolic acid) scaffold for ASC delivery. Healing was assessed by serial microcomputed tomography scans and histology. Freshly derived ASCs differed significantly from freeze-thaw ASCs in all markers examined. Surface EM showed distinct differences in cellular morphology. Proliferation, and osteogenic and adipogenic differentiation were all significantly hampered by the freeze-thaw process in vitro (*P?deleterious effects of the freeze-thaw process. PMID:20536327

  6. 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.

  7. 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 (ΔGDo) 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 α-lactalbumin, respectively. PMID:24039776

  8. Deleterious Passengers in Adapting Populations

    PubMed Central

    Good, Benjamin H.; Desai, Michael M.

    2014-01-01

    Most new mutations are deleterious and are eventually eliminated by natural selection. But in an adapting population, the rapid amplification of beneficial mutations can hinder the removal of deleterious variants in nearby regions of the genome, altering the patterns of sequence evolution. Here, we analyze the interactions between beneficial driver mutations and linked deleterious passengers during the course of adaptation. We derive analytical expressions for the substitution rate of a deleterious mutation as a function of its fitness cost, as well as the reduction in the beneficial substitution rate due to the genetic load of the passengers. We find that the fate of each deleterious mutation varies dramatically with the rate and spectrum of beneficial mutations and the deleterious substitution rate depends nonmonotonically on the population size and the rate of adaptation. By quantifying this dependence, our results allow us to estimate which deleterious mutations will be likely to fix and how many of these mutations must arise before the progress of adaptation is significantly reduced. PMID:25194161

  9. The rise and fall of deleterious mutation.

    PubMed

    Balbi, Kevin J; Feil, Edward J

    2007-12-01

    It is well established that selection is less efficient in small populations than in large ones. Here we review the impact of this effect by considering the gradual selective purging of deleterious mutation over time. We outline an approach to explore the dynamics of this process, and highlight its profound implications. PMID:17988836

  10. 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 ureas 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 ureas 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

  11. 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,...

  12. The deleterious metabolic and genotoxic effects of the bacterial metabolite p-cresol on colonic epithelial cells.

    PubMed

    Andriamihaja, Mireille; Lan, Annag; Beaumont, Martin; Audebert, Marc; Wong, Ximena; Yamada, Kana; Yin, Yulong; Tom, Daniel; Carrasco-Pozo, Catalina; Gotteland, Martin; Kong, Xiangfeng; Blachier, Franois

    2015-08-01

    p-Cresol that is produced by the intestinal microbiota from the amino acid tyrosine is found at millimolar concentrations in the human feces. The effects of this metabolite on colonic epithelial cells were tested in this study. Using the human colonic epithelial HT-29 Glc(-/+) cell line, we found that 0.8mM p-cresol inhibits cell proliferation, an effect concomitant with an accumulation of the cells in the S phase and with a slight increase of cell detachment without necrotic effect. At this concentration, p-cresol inhibited oxygen consumption in HT-29 Glc(-/+) cells. In rat normal colonocytes, p-cresol also inhibited respiration. Pretreatment of HT-29 Glc(-/+) cells with 0.8mM p-cresol for 1 day resulted in an increase of the state 3 oxygen consumption and of the cell maximal respiratory capacity with concomitant increased anion superoxide production. At higher concentrations (1.6 and 3.2mM), p-cresol showed similar effects but additionally increased after 1 day the proton leak through the inner mitochondrial membrane, decreasing the mitochondrial bioenergetic activity. At these concentrations, p-cresol was found to be genotoxic toward HT-29 Glc(-/+) and also LS-174T intestinal cells. Lastly, a decreased ATP intracellular content was observed after 3 days treatment. p-Cresol at 0.8mM concentration inhibits colonocyte respiration and proliferation. In response, cells can mobilize their "respiratory reserve." At higher concentrations, p-cresol pretreatment uncouples cell respiration and ATP synthesis, increases DNA damage, and finally decreases the ATP cell content. Thus, we have identified p-cresol as a metabolic troublemaker and as a genotoxic agent toward colonocytes. PMID:25881551

  13. Age Shall Not Weary Us: Deleterious Effects of Self-Regulation Depletion Are Specific to Younger Adults

    PubMed Central

    Dahm, Theresa; Neshat-Doost, Hamid Taher; Golden, Ann-Marie; Horn, Elizabeth; Hagger, Martin; Dalgleish, Tim

    2011-01-01

    Self-regulation depletion (SRD), or ego-depletion, refers to decrements in self-regulation performance immediately following a different self-regulation-demanding activity. There are now over a hundred studies reporting SRD across a broad range of tasks and conditions. However, most studies have used young student samples. Because prefrontal brain regions thought to subserve self-regulation do not fully mature until 25 years of age, it is possible that SRD effects are confined to younger populations and are attenuated or disappear in older samples. We investigated this using the Stroop color task as an SRD induction and an autobiographical memory task as the outcome measure. We found that younger participants (<25 years) were susceptible to depletion effects, but found no support for such effects in an older group (4065 years). This suggests that the widely-reported phenomenon of SRD has important developmental boundary conditions casting doubt on claims that it represents a general feature of human cognition. PMID:22039469

  14. 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 μg/L. This value was higher than the WHO value of 30 μg/L, indicating that this WHO guideline for uranium content in drinking water is very protective and might be reconsidered. PMID:24693537

  15. 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…

  16. 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

  17. 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 24months. 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

  18. In Utero Exposure to Low Doses of Bisphenol A Lead to Long-term Deleterious Effects in the Vagina1

    PubMed Central

    Schönfelder, G; Flick, B; Mayr, E; Talsness, C; Paul, M; Chahoud, I

    2002-01-01

    Abstract The origins of the “endocrine disrupter hypothesis” may be traced to reports on adolescent daughters born to women who had taken the highly potent synthetic estrogen, diethylstilbestrol, while pregnant, and who developed a rare form of vaginal cancer and adenocarcinoma. Bisphenol A (BPA) is an estrogenic chemical that is highly employed in the manufacture of a wide range of consumer products. Some observational studies have suggested that the amounts of BPA to which we are exposed could alter the reproductive organs of developing rodents. We examined the influence of BPA at low doses to address the questions of (a) whether in utero exposure affects the vagina of the offspring and (b) which mechanisms cause the toxic effects. Gravid Sprague-Dawley dams were administered either 0.1 (low dose) or 50 mg/kg per day BPA, the no observed effect level, or 0.2 mg/kg per day 17α-ethinyl estradiol by gavage. Striking morphological changes were observed in the vagina of postpubertal offspring leading us to examine vaginal estrogen receptor (ER) expression because BPA binds to the ERα, which is important for growth of the vaginal epithelium. We show that the full -length ERα is not expressed during estrus in the vagina of female offspring exposed to either dose of BPA when compared to the control group, whereas ERα expression does not differ from the control group during the diestrus stage. ERα downregulation seems to be responsible for the observed altered vaginal morphology. PMID:11896564

  19. In vitro drug treatments reduce the deleterious effects of aggregates containing polyAla expanded PHOX2B proteins.

    PubMed

    Di Zanni, Eleonora; Bachetti, Tiziana; Parodi, Sara; Bocca, Paola; Prigione, Ignazia; Di Lascio, Simona; Fornasari, Diego; Ravazzolo, Roberto; Ceccherini, Isabella

    2012-01-01

    Heterozygous in frame duplications of the PHOX2B gene, leading to polyalanine (polyAla) expansions ranging from +5 to +13 residues of a 20-alanine stretch, have been identified in the vast majority of patients affected with Congenital Central Hypoventilation Syndrome (CCHS), a rare neurocristopathy characterized by absence of adequate autonomic control of respiration with decreased sensitivity to hypoxia and hypercapnia. Ventilatory supports such as tracheostomy, nasal mask or diaphragm pacing represent the only options available for affected. We have already shown that the severity of the CCHS phenotype correlates with the length of polyAla expansions, ultimately leading to formation of toxic intracytoplasmic aggregates and impaired PHOX2B mediated transactivation of target gene promoters, such as DBH. At present, there is no specific treatment to reduce cell aggregates and to ameliorate patients' respiration. In this work, we have undertaken in vitro analyses aimed at assessing the effects of molecules on the cellular response to polyAla PHOX2B aggregates. In particular, we tested 17-AAG, ibuprofen, 4-PBA, curcumin, trehalose, congo red and chrysamine G for their ability to i) recover the nuclear localisation of polyAla expanded PHOX2B, ii) rescue of PHOX2B mediated transactivation of the DBH promoter, and iii) clearance of PHOX2B (+13 Ala) aggregates. Our data have suggested that 17-AAG and curcumin are effective in vitro in both rescuing the nuclear localization and transactivation activity of PHOX2B carrying the largest expansion of polyAla and promoting the clearance of aggregates of these mutant proteins inducing molecular mechanisms such as ubiquitin-proteasome (UPS), autophagy and heat shock protein (HSP) systems. PMID:21964250

  20. Bacteriophage administration significantly reduces Shigella colonization and shedding by Shigella-challenged mice without deleterious side effects and distortions in the gut microbiota

    PubMed Central

    Mai, Volker; Ukhanova, Maria; Reinhard, Mary K; Li, Manrong; Sulakvelidze, Alexander

    2015-01-01

    We used a mouse model to establish safety and efficacy of a bacteriophage cocktail, ShigActive™, in reducing fecal Shigella counts after oral challenge with a susceptible strain. Groups of inbred C57BL/6J mice challenged with Shigella sonnei strain S43-NalAcR were treated with a phage cocktail (ShigActive™) composed of 5 lytic Shigella bacteriophages and ampicillin. The treatments were administered (i) 1 h after, (ii) 3 h after, (iii) 1 h before and after, and (iv) 1 h before bacterial challenge. The treatment regimens elicited a 10- to 100-fold reduction in the CFU's of the challenge strain in fecal and cecum specimens compared to untreated control mice, (P < 0.05). ShigActiveTM treatment was at least as effective as treatment with ampicillin but had a significantly less impact on the gut microbiota. Long-term safety studies did not identify any side effects or distortions in overall gut microbiota associated with bacteriophage administration. Shigella phages may be therapeutically effective in a “classical phage therapy” approach, at least during the early stages after Shigella ingestion. Oral prophylactic “phagebiotic” administration of lytic bacteriophages may help to maintain a healthy gut microbiota by killing specifically targeted bacterial pathogens in the GI tract, without deleterious side effects and without altering the normal gut microbiota. PMID:26909243

  1. 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.

  2. 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

  3. 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...

  4. 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...

  5. Leptin deficiency unmasks the deleterious effects of impaired peroxisome proliferator-activated receptor gamma function (P465L PPARgamma) in mice.

    PubMed

    Gray, Sarah L; Nora, Edoardo Dalla; Grosse, Johannes; Manieri, Monia; Stoeger, Tobias; Medina-Gomez, Gema; Burling, Keith; Wattler, Sigrid; Russ, Andreas; Yeo, Giles S H; Chatterjee, V Krishna; O'Rahilly, Stephen; Voshol, Peter J; Cinti, Saverio; Vidal-Puig, Antonio

    2006-10-01

    Peroxisome proliferator-activated receptor (PPAR)gamma is a key transcription factor facilitating fat deposition in adipose tissue through its proadipogenic and lipogenic actions. Human patients with dominant-negative mutations in PPARgamma display lipodystrophy and extreme insulin resistance. For this reason it was completely unexpected that mice harboring an equivalent mutation (P465L) in PPARgamma developed normal amounts of adipose tissue and were insulin sensitive. This finding raised important doubts about the interspecies translatability of PPARgamma-related findings, bringing into question the relevance of other PPARgamma murine models. Here, we demonstrate that when expressed on a hyperphagic ob/ob background, the P465L PPARgamma mutant grossly exacerbates the insulin resistance and metabolic disturbances associated with leptin deficiency, yet reduces whole-body adiposity and adipocyte size. In mouse, coexistence of the P465L PPARgamma mutation and the leptin-deficient state creates a mismatch between insufficient adipose tissue expandability and excessive energy availability, unmasking the deleterious effects of PPARgamma mutations on carbohydrate metabolism and replicating the characteristic clinical symptoms observed in human patients with dominant-negative PPARgamma mutations. Thus, adipose tissue expandability is identified as an important factor for the development of insulin resistance in the context of positive energy balance. PMID:17003330

  6. Protective Effect of Parsley Juice (Petroselinum crispum, Apiaceae) against Cadmium Deleterious Changes in the Developed Albino Mice Newborns (Mus musculus) Brain

    PubMed Central

    Allam, Ahmed A.; Maodaa, Salah N.; Abo-Eleneen, Rasha; Ajarem, Jamaan

    2016-01-01

    Parsley was used as a probe of the current experiment to prevent the behavioral, morphological and biochemical changes in the newborn brain following the administration of cadmium (Cd) to the pregnant mice. The nonanesthetized pregnant mice were given daily parsley juice (Petroselinum crispum) at doses of 20 mg/kg and 10 mg/kg. Pregnant mothers were given Cd at a dose of 30 mg/kg divided into 3 equal times. The newborns have been divided into 6 groups: Group A, mothers did not take treatment; Groups B and C, mothers were treated with low and high dose of parsley, respectively; Group D, mothers were treated only with Cd (perinatal intoxication); Groups E and F, mothers were treated with Cd doses and protected by low and high doses of parsley, respectively. Light microscopy showed that Cd-induced neuronal degeneration by chromatolysis and pyknosis in the brain regions. The low dose of parsley 10 g/kg/day exhibited significant effects in neutralizing and reducing the deleterious changes due to Cd exposure during pregnancy on the behavioral activities, neurotransmitters, oxidative stress, and brain neurons morphology of the mice newborns. PMID:26966507

  7. 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.

  8. Thermal effects on fish ecology

    USGS Publications Warehouse

    Coutant, Charles C.

    1976-01-01

    Of all the environmental factors that influence aquatic organisms, temperature is the most all-pervasive. There is always an environmental temperature while other factors may or may not be present to exert their effects. Fish are, for all practical purposes, thermal conformers, or obligate poikilotherms. That is, they are able to exert little significant influence on maintaining a certain body temperature by specialized metabolic or behavioral means. Their body temperature thus fluctuates nearly in concert with the temperature of their aquatic medium (although particularly large, actively-moving fish such as tuna have deep muscle temperatures slightly higher than the water). Intimate contact at the gills of body fluids with the outside water and the high specific heat of water provide a very efficient heat exchanger that insures this near identity of internal and external temperatures.

  9. Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the adult rat brain.

    PubMed

    Rivera, Patricia; Blanco, Eduardo; Bindila, Laura; Alen, Francisco; Vargas, Antonio; Rubio, Leticia; Pavn, Francisco J; Serrano, Antonia; Lutz, Beat; Rodrguez de Fonseca, Fernando; Surez, Juan

    2015-01-01

    Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of histone-3 (phospho-H3+) and the replicating cell DNA marker 5-bromo-2'-deoxyuridine (BrdU+) in the main neurogenic zones of adult brain: subgranular zone of dentate gyrus (SGZ), subventricular zone of lateral ventricles (SVZ) and hypothalamus. Animals were allowed ad libitum ethanol intake (7.3 1.1 g/kg/day) after a controlled isocaloric pair-feeding period of sucrose and alcoholic diets. Alcohol intake reduced the number of BrdU+ cells in SGZ, SVZ, and hypothalamus. The treatments (URB597, ACEA, JWH133) exerted a differential increase in alcohol consumption over time, but JWH133 specifically counteracted the deleterious effect of ethanol on NPC proliferation in the SVZ and SGZ, and ACEA reversed this effect in the SGZ only. JWH133 also induced an increased number of BrdU+ cells expressing neuron-specific ?3-tubulin in the SVZ and SGZ. These results indicated that the specific activation of CB2 receptors rescued alcohol-induced impaired NPC proliferation, which is a potential clinical interest for the risk of neural damage in alcohol dependence. PMID:26483633

  10. Pharmacological activation of CB2 receptors counteracts the deleterious effect of ethanol on cell proliferation in the main neurogenic zones of the adult rat brain

    PubMed Central

    Rivera, Patricia; Blanco, Eduardo; Bindila, Laura; Alen, Francisco; Vargas, Antonio; Rubio, Leticia; Pavón, Francisco J.; Serrano, Antonia; Lutz, Beat; Rodríguez de Fonseca, Fernando; Suárez, Juan

    2015-01-01

    Chronic alcohol exposure reduces endocannabinoid activity and disrupts adult neurogenesis in rodents, which results in structural and functional alterations. Cannabinoid receptor agonists promote adult neural progenitor cell (NPC) proliferation. We evaluated the protective effects of the selective CB1 receptor agonist ACEA, the selective CB2 receptor agonist JWH133 and the fatty-acid amide-hydrolase (FAAH) inhibitor URB597, which enhances endocannabinoid receptor activity, on NPC proliferation in rats with forced consumption of ethanol (10%) or sucrose liquid diets for 2 weeks. We performed immunohistochemical and stereological analyses of cells expressing the mitotic phosphorylation of histone-3 (phospho-H3+) and the replicating cell DNA marker 5-bromo-2'-deoxyuridine (BrdU+) in the main neurogenic zones of adult brain: subgranular zone of dentate gyrus (SGZ), subventricular zone of lateral ventricles (SVZ) and hypothalamus. Animals were allowed ad libitum ethanol intake (7.3 ± 1.1 g/kg/day) after a controlled isocaloric pair-feeding period of sucrose and alcoholic diets. Alcohol intake reduced the number of BrdU+ cells in SGZ, SVZ, and hypothalamus. The treatments (URB597, ACEA, JWH133) exerted a differential increase in alcohol consumption over time, but JWH133 specifically counteracted the deleterious effect of ethanol on NPC proliferation in the SVZ and SGZ, and ACEA reversed this effect in the SGZ only. JWH133 also induced an increased number of BrdU+ cells expressing neuron-specific β3-tubulin in the SVZ and SGZ. These results indicated that the specific activation of CB2 receptors rescued alcohol-induced impaired NPC proliferation, which is a potential clinical interest for the risk of neural damage in alcohol dependence. PMID:26483633

  11. Properties and modeling of GWAS when complex disease risk is due to non-complementing, deleterious mutations in genes of large effect.

    PubMed

    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

  12. 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

  13. Deleterious background selection with recombination

    SciTech Connect

    Hudson, R.R.; Kaplan, N.L.

    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.

  14. 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...

  15. Developmental expression of Musashi-1 and Musashi-2 RNA-binding proteins during spermatogenesis: analysis of the deleterious effects of dysregulated expression.

    PubMed

    Sutherland, Jessie M; Fraser, Barbara A; Sobinoff, Alexander P; Pye, Victoria J; Davidson, Tara-Lynne; Siddall, Nicole A; Koopman, Peter; Hime, Gary R; McLaughlin, Eileen A

    2014-05-01

    Spermatogenesis is a complex developmental process whereby diploid spermatogenic stem cells become haploid and undergo a series of morphological changes to produce physically mature spermatozoa. Crucial to this process are a number of RNA-binding proteins, responsible for the posttranscriptional control of essential mRNAs and particularly pertinent to the two periods of inactive transcription that occur in spermatogenesis. One such group of RNA-binding proteins is the Musashi family, specifically Musashi-1 (MSI1) and Musashi-2 (MSI2), which act as key translational regulators in various stem cell populations and have been linked with the induction of tumorigenesis. In the present study, we examined the differential expression of mammalian MSI1 and MSI2 during germ cell development in the mouse testis. MSI1 was found to be predominately localized in mitotic gonocytes and spermatogonia, whereas MSI2 was detected in meiotic spermatocytes and differentiating spermatids. Extensive examination of the function of Musashi in spermatogenesis was achieved through the use of two transgenic mouse models with germ cell-specific overexpression of full-length isoforms of Msi1 or Msi2. These models demonstrated that aberrant expression of either Msi1 or Msi2 has deleterious effects on normal spermatogenesis, with Msi2 overexpression resulting in male sterility. Studies undertaken on human testicular seminoma tumors provide further insights into the relevance of MSI1 and MSI2 overexpression as diagnostic markers to human stem cell cancers. Overall this study provides further evidence for the unique functions that RNA-binding protein isoforms occupy within spermatogenesis, and introduces the potential manipulation of the Musashi family proteins to elucidate the mechanisms of posttranscriptional gene expression during germ cell development. PMID:24671879

  16. 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

  17. 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 Seaa region where 3040% 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

  18. 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

  19. Phthalate esters: Testing for ecological effects

    SciTech Connect

    Brown, D.; Thompson, R.; Croudace, C.; Stewart, K.; Williams, N.

    1995-12-31

    Ortho-phthalate esters are produced in high tonnages for use as plasticizers, in particular for PVC. Their physical chemical properties are typically very low water solubility and high octanol/water partition coefficient. This combination of properties presents a number of experimental difficulties in the design and interpretation of ecological effect studies. These difficulties are described and results presented showing techniques for the performance of reproduction studies with the water flea, Daphnia magna, in aqueous solution and with the midge, Chironomus riparius, in sediments. The results which showed no effect for the phthalate esters tested are discussed in the context of other ecotoxicity data obtained on these products.

  20. Pantoea agglomerans: a marvelous bacterium of evil and good.Part I. Deleterious effects: Dust-borne endotoxins and allergens - focus on cotton dust.

    PubMed

    Dutkiewicz, Jacek; Mackiewicz, Barbara; Lemieszek, Marta Kinga; Golec, Marcin; Milanowski, Janusz

    2015-12-13

    The ubiquitous Gram-negative bacterium Pantoea agglomerans (synonyms: Enterobacter agglomerans, Erwinia herbicola) is known both as an epiphytic microbe developing on the surface of plants and as an endophytic organism living inside the plants. The bacterium occurs also abundantly in plant and animal products, in the body of arthropods and other animals, in water, soil, dust and air, and occasionally in humans. From the human viewpoint, the role of this organism is ambiguous, both deleterious and beneficial: on one side it causes disorders in people exposed to inhalation of organic dusts and diseases of crops, and on the other side it produces substances effective in the treatment of cancer and other diseases of humans and animals, suppresses the development of various plant pathogens, promotes plant growth, and appears as a potentially efficient biofertilizer and bioremediator. P. agglomerans was identified as a predominant bacterium on cotton plant grown all over the world, usually as an epiphyte, rarely as pathogen. It is particularly numerous on cotton bract after senescence. During processing of cotton in mills, bacteria and their products are released with cotton dust into air and are inhaled by workers, causing respiratory and general disorders, usually defined as byssinosis. The most adverse substance is endotoxin, a heteropolymer macromolecule present in the outermost part of the cell wall, consisting of lipopolysaccharide (LPS) as a major constituent, phospholipids and protein. The numerous experiments carried out in last quarter of XXth century on laboratory animals and human volunteers supported a convincing evidence that the inhaled endotoxin produced by P. agglomerans causes numerous pathologic effects similar to those elicited by cotton dust, such as influx of free lung cells into airways and activation of alveolar macrophages which secrete mediators (prostaglandins, platelet-activating factor, interleukin-1, tumor necrosis factor) that cause accumulation of platelets in pulmonary capillaries initiating an acute and chronic inflammation resulting in endothelial cell damage and extravasation of cells and fluids into the lung interstitium. These changes cause bronchoconstriction, the decrement of lung function expressed as reduction of forced expiratory volume in one second (FEV1) and/or diffusion capacity, increase in the airway hyperreactivity and subjective symptoms such as fever, airway irritation and chest tightness. The conclusions from these experiments, performed mostly 2-3 decades ago, did not loose their actuality until recently as so far no other cotton dust component was identified as a more important work-related hazard than bacterial endotoxin. Though also other microbial and plant constituents are considered as potential causative agents of byssinosis, the endotoxin produced by Pantoea agglomerans and other Gram-negative bacteria present in cotton dust is still regarded as a major cause of this mysterious disease. PMID:26706959

  1. 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...

  2. Efficient purging of deleterious mutations in plants with haploid selfing

    SciTech Connect

    Szovenyi, Peter; Shaw, Jon; Yang, Xiaohan; Devos, Nicolas

    2014-05-30

    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 non-synonymous 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.

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

    PubMed Central

    Szvnyi, Pter; Devos, Nicolas; Weston, David J.; Yang, Xiaohan; Hock, Zsfia; 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. Potential Ecological Effects of Contaminants in the Exposed Par Pond Sediments

    SciTech Connect

    Paller, M.H.; 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.

  5. Effects of Global Warming on Vibrio Ecology.

    PubMed

    Vezzulli, Luigi; Pezzati, Elisabetta; Brettar, Ingrid; Höfle, Manfred; Pruzzo, Carla

    2015-06-01

    Vibrio-related infections are increasing worldwide both in humans and aquatic animals. Rise in global sea surface temperature (SST), which is approximately 1 °C higher now than 140 years ago and is one of the primary physical impacts of global warming, has been linked to such increases. In this chapter, major known effects of increasing SST on the biology and ecology of vibrios are described. They include the effects on bacterial growth rate, both in the field and in laboratory, culturability, expression of pathogenicity traits, and interactions with aquatic organisms and abiotic surfaces. Special emphasis is given to the effect of ocean warming on Vibrio interactions with zooplankters, which represent one of the most important aquatic reservoirs for these bacteria. The reported findings highlight the biocomplexity of the interactions between vibrios and their natural environment in a climate change scenario, posing the need for interdisciplinary studies to properly understand the connection between ocean warming and persistence and spread of vibrios in sea waters and the epidemiology of the diseases they cause. PMID:26185070

  6. Ecology: Nonlinearity and the Moran effect

    NASA Astrophysics Data System (ADS)

    Blasius, Bernd; Stone, Lewi

    2000-08-01

    The study of synchronization phenomena in ecology is important because it helps to explain interactions between population dynamics and extrinsic environmental variation. Grenfell et al. have examined synchronized fluctuations in the sizes of two populations of feral sheep which, although situated on close but isolated islands, were nevertheless strongly correlated (observed value of the population correlation, rp, 0.685). Using a nonlinear threshold model, they argue that this level of population correlation could only be explained if environmental stochasticity was correlated between the islands, with the environmental correlation, re, higher than 0.9 ``on average'' (Fig. 1a). This unusually high environmental correlation is far greater than would be predicted by the Moran effect, which states that the population correlation will equal the environmental correlation in a linear system. Grenfell et al. imply that a simple nonlinearity in population growth can mask or even destroy the Moran effect. Here we show that these surprising results are an artefact of the techniques used to measure noise correlations and synchronization.

  7. The chemical ecology of Harmonia axyridis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We review the chemical ecology of the ladybird beetle Harmonia axyridis from the perspective of its invasiveness and the deleterious effects it exerts in the regions it has colonised. We outline the nature and quantification of its chemical defence, and discuss the protection this provides from natu...

  8. Acute deleterious effects of cocaine on cardiac conduction, hemodynamics, and ventricular fibrillation threshold: effects of interaction with a selective dopamine D1 antagonist SCH 39166.

    PubMed

    Kanani, P M; Guse, P A; Smith, W M; Barnett, A; Ellinwood, E H

    1998-07-01

    Cocaine has demonstrated cardiotoxicity that has led to sudden death by unknown mechanisms. SCH 39166, a selective dopaminergic D1-receptor antagonist, suppresses the compulsive drug-intake actions of cocaine in primates. This study examined the cumulative toxic effects of cocaine after the long-term administration of SCH 39166. After pretreatment with oral placebo/SCH 39166 for 5 days, an i.v. infusion of 0.25 mg/kg/min of cocaine HCl was delivered to 14 anesthetized dogs, and cardiac conduction, arterial blood pressure, ventricular refractoriness, and arrhythmogenesis were examined. The cocaine infusion was stopped when QRS width increased by 20% from baseline (QRS20). In Coc + Placebo regimen, the QRS and His-Ventricular (HV) intervals showed a dose-dependent lengthening. Initially, the mean blood pressure (MBP) increased followed by a precipitate decrease at a mean dose of 2.03 +/- 0.5 mg/kg of cocaine. At QRS20, the ventricular effective refractory period (ERP) increased significantly, whereas the ventricular fibrillation threshold (VFT) showed a significant reduction from the baseline. In Coc + SCH, the QRS, HV intervals, and ERP increased similarly, but the decrease in MBP was attenuated, and the VFT was increased. A relatively small infusion of cocaine causes a hemodynamic compromise. The His-ventricular conduction delay and lengthened ERP suggest a predominant direct local anesthetic effect. Cocaine additionally decreased the VFT, suggesting an increased susceptibility to VF. SCH 39166 did not potentiate the cardiotoxic effects of cocaine. It displayed a protective trend by suppressing the arrhythmogenic effects and the hemodynamic compromise caused by cocaine. PMID:9676719

  9. 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

    2010-01-01

    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

  10. 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.

  11. 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…

  12. 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

  13. Ecology.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on various ecological topics. The bulletins have these titles: Schoolyard Laboratories, Owls and Predators, The Forest Community, Life in Freshwater Marshes, Camouflage in the Animal World, Life in the Desert, The

  14. Ecology.

    ERIC Educational Resources Information Center

    National Audubon Society, New York, NY.

    This set of teaching aids consists of nine Audubon Nature Bulletins, providing teachers and students with informational reading on various ecological topics. The bulletins have these titles: Schoolyard Laboratories, Owls and Predators, The Forest Community, Life in Freshwater Marshes, Camouflage in the Animal World, Life in the Desert, The…

  15. 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.

  16. 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 ...

  17. Linking effects of anthropogenic debris to ecological impacts

    PubMed Central

    Browne, Mark Anthony; Underwood, A. J.; Chapman, M. G.; Williams, Rob; Thompson, Richard C.; van Franeker, Jan A.

    2015-01-01

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the ‘health’, feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. PMID:25904661

  18. Linking effects of anthropogenic debris to ecological impacts.

    PubMed

    Browne, Mark Anthony; Underwood, A J; Chapman, M G; Williams, Rob; Thompson, Richard C; van Franeker, Jan A

    2015-05-22

    Accelerated contamination of habitats with debris has caused increased effort to determine ecological impacts. Strikingly, most work on organisms focuses on sublethal responses to plastic debris. This is controversial because (i) researchers have ignored medical insights about the mechanisms that link effects of debris across lower levels of biological organization to disease and mortality, and (ii) debris is considered non-hazardous by policy-makers, possibly because individuals can be injured or removed from populations and assemblages without ecological impacts. We reviewed the mechanisms that link effects of debris across lower levels of biological organization to assemblages and populations. Using plastic, we show microplastics reduce the 'health', feeding, growth and survival of ecosystem engineers. Larger debris alters assemblages because fishing-gear and tyres kill animals and damage habitat-forming plants, and because floating bottles facilitate recruitment and survival of novel taxa. Where ecological linkages are not known, we show how to establish hypothetical links by synthesizing studies to assess the likelihood of impacts. We also consider how population models examine ecological linkages and guide management of ecological impacts. We show that by focusing on linkages to ecological impacts rather than the presence of debris and its sublethal impacts, we could reduce threats posed by debris. PMID:25904661

  19. Evidence for a slightly deleterious effect of intron polymorphisms at the EF1alpha gene in the deep-sea hydrothermal vent bivalve Bathymodiolus.

    PubMed

    Faure, B; Bierne, N; Tanguy, A; Bonhomme, F; Jollivet, D

    2007-12-30

    A multilocus analysis was initiated in order to infer the general effect of demography and the indirect effect of positive selection on some chromosome segments in Bathymodiolus. Mussels of the genus Bathymodiolus inhabit the very hostile, fragmented and variable environment of deep-sea hydrothermal vents which is thought to cause recurrent population bottlenecks via extinction/colonisation processes and adaptation to new environmental conditions. In the course of this work we discovered that the assumption of neutrality of non-coding polymorphisms usually made in genome scan experiments was likely to be violated at one of the loci we analysed. The direct effect of slight purifying selection on non-coding polymorphisms shares many resemblances with the indirect effect of positive selection through genetic hitchhiking. Combining polymorphism with divergence data for several closely related species allowed us to obtain different expectations for the direct effect of negative selection and the indirect effect of positive selection. We observed a strong excess of rare non-coding polymorphisms at the second intron of the EF1alpha gene in the two species Bathymodiolus azoricus and Bathymodiolus thermophilus, while two other loci, the mitochondrial COI gene and an intron of the Lysozyme gene, did not exhibit such a deviation. In addition, the divergence rate of the EF1alpha intron was estimated to be unexpectedly low when calibrated using the closure of the Panama Isthmus that interrupted gene flow between the two species. The polymorphism to divergence ratio was similar to the one observed for the other two loci, in accordance to the hypothesis of purifying selection. We conclude that slight purifying selection is likely to act on polymorphic intronic mutations of the EF1alpha second intron and discuss the possible relationship with the specific biology of Bathymodiolus mussels. PMID:17707599

  20. The deleterious effects of high inbreeding on male Drosophila melanogaster attractiveness are observed under competitive but not under non-competitive conditions.

    PubMed

    Valtonen, Terhi M; Roff, Derek A; Rantala, Markus J

    2014-03-01

    In order for the male courtship traits to honestly signal quality they need to be condition-dependent. Moreover, if these traits capture genetic variation in condition they should resemble life-history traits in being subject to strong directional selection and, consequently, suffer strong inbreeding depression. In this study we investigated the effect of high inbreeding on male attractiveness by assessing mating success, mating speed and copulation duration of inbred, outbred and crossbred (constructed by crossing separate, randomly chosen inbred lines) males of Drosophila melanogaster. When set to compete against a standardized competitor and compared to the success rate of the crossbred lines, inbreeding significantly reduced male mating success. Under competition, outbred males initiated copulation significantly sooner than crossbred and inbred males. Under non-competitive conditions, no effect of inbreeding was found on either mating speed or copulation duration. Both mating success and mating speed showed much higher inbreeding depression than male size. PMID:24413901

  1. Deleterious effect of salusin-? in paraventricular nucleus on sympathetic activity and blood pressure via NF-?B signaling in a rat model of obesity hypertension.

    PubMed

    Huang, Xiaodong; Wang, Yanchun; Ren, Kuang

    2015-08-01

    The paraventricular nucleus (PVN) has been shown to play a critical role in regulating blood pressure and sympathetic activity in obesity hypertension (OH). Salusin-? is a bioactive peptide with potential roles in mediating cardiovascular activity. The study was designed to test the hypothesis that salusin-? in the PVN can modulate sympathetic activity and blood pressure in OH. Male Sprague-Dawley rats were used to induce OH by a 12-week feeding of a high-fat diet (42% kcal as fat). Microinjection of salusin-? into the PVN increased the renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP) and heart rate (HR) in a dose-dependent manner, whereas salusin-? antibody elicited significant decreases in RSNA, MAP and HR, and abolished the effects of salusin-? only in the OH rats. As expected, the OH rats had a higher norepinephrine level, which was further increased by salusin-?. Furthermore, salusin-? in the PVN accelerated the nuclear translocation of the p65 subunit of nuclear factor kappa B (NF-KB) and the degradation of IKB-? (an endogenous inhibitor of NF-KB). Pretreatment with pyrrolidine dithiocarbamate (an exogenous inhibitor of NF-KB) decreased RSNA, MAP and HR, and abolished the effects of salusin-? in the PVN in the OH rats. We concluded that salusin-? in the PVN markedly increased sympathetic outflow and blood pressure in diet-induced OH rats via NF-?B signaling. PMID:26380524

  2. Symbiosis-Promoting and Deleterious Effects of NopT, a Novel Type 3 Effector of Rhizobium sp. Strain NGR234?

    PubMed Central

    Dai, Wei-Jun; Zeng, Yong; Xie, Zhi-Ping; Staehelin, Christian

    2008-01-01

    Establishment of symbiosis between certain host plants and nitrogen-fixing bacteria (rhizobia) depends on type 3 effector proteins secreted via the bacterial type 3 secretion system (T3SS). Here, we report that the open reading frame y4zC of strain NGR234 encodes a novel rhizobial type 3 effector, termed NopT (for nodulation outer protein T). Analysis of secreted proteins from NGR234 and T3SS mutants revealed that NopT is secreted via the T3SS. NopT possessed autoproteolytic activity when expressed in Escherichia coli or human HEK 293T cells. The processed NopT exposed a glycine (G50) to the N terminus, which is predicted to be myristoylated in eukaryotic cells. NopT with a point mutation at position C93, H205, or D220 (catalytic triad) showed strongly reduced autoproteolytic activity, indicating that NopT is a functional protease of the YopT-AvrPphB effector family. When transiently expressed in tobacco plants, proteolytically active NopT elicited a rapid hypersensitive reaction. Arabidopsis plants transformed with nopT showed chlorotic and necrotic symptoms, indicating a cytotoxic effect. Inoculation experiments with mutant derivatives of NGR234 indicated that NopT affected nodulation either positively (Phaseolus vulgaris cv. Yudou No. 1; Tephrosia vogelii) or negatively (Crotalaria juncea). We suggest that NopT-related polymorphism may be involved in evolutionary adaptation of NGR234 to particular host legumes. PMID:18487326

  3. 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 μg L(-1)) for S-metolachlor and 100× for irgarol (1.0 μg L(-1)) and diuron (4.0 μg 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 μg L(-1) for irgarol or S-metolachlor, and 0.04 μg 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

  4. SHORT-TERM EFFECTS OF DIURON ON CATFISH POND ECOLOGY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We examined the effects of diuron treatment on catfish pond ecology under commercial culture conditions. Nine weekly treatments of diuron (0.01 mg/L) were applied to nine 0.4-ha experimental ponds; six ponds served as controls. Water and fish samples were collected from all ponds each week for che...

  5. 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. Hammers 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...

  6. 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...

  7. 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...

  8. Estimated ecological effects of triazine use of surface waters

    SciTech Connect

    Mercurio, S.D.

    1996-10-01

    Based on the current intensive use of triazines in agriculture in the northern portions of the Midwest, ecological impacts have been evaluated in surface waters. Considerations from application methods to stream concentrations predict a range of impacts using current toxicity models. Standard {open_quotes}static{close_quotes} LC{sub 50}s predict only algal mortality at peak runoff, while laboratory flow-through systems indicate seasonal impacts on primary stream productivity. Mesocosms further observe indirect effects on numerous species during the year. Microcosm and flow-through wetland mesocosm studies indicate primary effects during the growing season on algal populations, magnified by zooplankton bloom stresses and indirect effects on dissolved oxygen and nutrient concentrations. If the river continuum model is considered in combination with triazine concentrations, clear untoward effects on stream ecosystems occur with current practices. The use of banding application or other remediation techniques for positive ecological and economic gains as proven alternatives to current uses are encouraged.

  9. Ecological effects of mercury in aquatic ecosystems

    SciTech Connect

    Suchanek, T.H.; Richerson, P.J.

    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.

  10. A New Approach to Ecological Risk Assessment: Simulating Effects of Global Warming on Complex Ecological Networks

    NASA Astrophysics Data System (ADS)

    Zhou, Yun; Brose, Ulrich; Kastenberg, William; Martinez, Neo D.

    The field of Ecological Risk Assessment (ERA) has been under development since the 1970s. Early ERA borrowed basic concepts from human health risk assessment (HRA) methodology [NAS 1983]. However, because of the nature of an ecosystem, there is a fundamental difference between HRA and ERA. In an HRA, the only receptor is a single human being and the concerned endpoints are always associated with human health issues, such as the risk of cancer. In ERA, however, entire populations, communities and ecosystems are at risk, and ERA must rigorously assess these more complex and larger scaled concerns. Many investigators have attempted to develop a new paradigm for ERA that can deal with this intrinsic distinction. Currently, a six-step framework is now widely used by the U.S. EPA and its contractors. This new paradigm is characterized by: (1) receptor identification, (2) hazard identification, (3) endpoint identification, (4) exposure assessment, (5) doseresponse assessment and (6) risk characterization [Lipton et al. 1993, Suter 1993]. The six-step framework identifies receptors at risk, possible hazards related to certain receptors, and chooses appropriate assessment and measurement endpoints [Suter 1990]. While the additional receptor and endpoint identifications improve on the traditional framework, single-species laboratory toxicity tests typically estimate ecological responses simply by predicting an environmental concentration associated with a certain stressor divided by the no-observed effect concentration (NOEC) for that stressor. This "Hazard Quotient" (HQ) approach ignores interactions between species that are critical to the functioning of communities and ecosystems.

  11. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  12. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 2 2012-04-01 2012-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  13. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  14. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 2 2011-04-01 2011-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  15. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  16. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Added poisonous or deleterious substances. 509.6...-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  17. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 2 2013-04-01 2013-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  18. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 2 2014-04-01 2014-04-01 false Added poisonous or deleterious substances. 109.6...-PACKAGING MATERIAL General Provisions § 109.6 Added poisonous or deleterious substances. (a) Use of an added... approved under the criteria of section 409 of the act, or when the added poisonous or deleterious...

  19. 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

  20. 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

  1. Visual Search in Ecological and Non-Ecological Displays: Evidence for a Non-Monotonic Effect of Complexity on Performance

    PubMed Central

    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

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

    PubMed

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

    2008-07-15

    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

  3. 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

  4. 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 ...

  5. Predicting ecological effects of pollutants: A role for marine mesocosms

    SciTech Connect

    Ward, T.J.

    1994-12-31

    The major uncertainty in predicting the ecological effects of a pollutant is the relationship between dose and the ecological response. Mesocosms may be used to simulate population-level biological processes and to estimate the nature and shape of dose-related responses to pollutants, for use in predictive evaluations of pollutant impacts. To ensure that responses observed in mesocosm tests are representative it is necessary to confirm that the simulated processes operate at rates similar to those found in the field. Pilot experiments were conducted in small marine mesocosms simulating major processes in two local habitat types: unvegetated sand and sand colonized by the brown macroalga Sargassum. The results showed that for a range of variates (such as the % of egg-bearing harpacticoid copepods, or the chlorophyll a concentration in surface sediments) the mean values for measurements in the tanks over a 9 week period did not consistently converge or diverge from those in the field. Also, for a number of the variates, a modelled decrease of more than about 60% in the mean could be detected with greater than 80% statistical power. This indicates that the effects of a pollutant could be detected with acceptable power. Use of a combination of such variates based on different functional or taxonomic groups for pollutant effects testing could greatly decrease uncertainty about the predicted effects of pollutants discharged to these habitats.

  6. 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

  7. 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

  8. Effect of Ecological Restoration on Body Condition of a Predator

    PubMed Central

    González-Tokman, Daniel; Martínez-Garza, Cristina

    2015-01-01

    Ecological restoration attempts to recover the structure and function of ecosystems that have been degraded by human activities. A crucial test of ecosystem recovery would be to determine whether individuals in restored environments are as healthy as those in conserved environments. However, the impact of restoration on physiology of terrestrial animals has never been tested. Here, we evaluated the effect of two restoration methods on body condition measured as body size, body mass, lipid and muscle content of the spider Nephila clavipes in a tropical dry forest that has suffered chronic disturbance due to cattle grazing. We used experimental plots that had been excluded from disturbance by cattle grazing during eight years. Plots were either planted with native trees (i. e. maximal intervention), or only excluded from disturbance (i. e. minimal intervention), and were compared with control conserved (remnants of original forest) and disturbed plots (where cattle is allowed to graze). We predicted (1) better body condition in spiders of conserved and restored sites, compared to disturbed sites, and (2) better body condition in plots with maximal intervention than in plots with minimal intervention. The first prediction was not supported in males or females, and the second prediction was only supported in females: body dry mass was higher in planted than in conserved plots for spiders of both sexes and also higher that in disturbed plots for males, suggesting that plantings are providing more resources. We discuss how different life histories and environmental pressures, such as food availability, parasitism, and competition for resources can explain our contrasting findings in male and female spiders. By studying animal physiology in restoration experiments it is possible to understand the mechanistic basis of ecological and evolutionary processes that determine success of ecological restoration. PMID:26226363

  9. Effect of Ecological Restoration on Body Condition of a Predator.

    PubMed

    Gonzlez-Tokman, Daniel; Martnez-Garza, Cristina

    2015-01-01

    Ecological restoration attempts to recover the structure and function of ecosystems that have been degraded by human activities. A crucial test of ecosystem recovery would be to determine whether individuals in restored environments are as healthy as those in conserved environments. However, the impact of restoration on physiology of terrestrial animals has never been tested. Here, we evaluated the effect of two restoration methods on body condition measured as body size, body mass, lipid and muscle content of the spider Nephila clavipes in a tropical dry forest that has suffered chronic disturbance due to cattle grazing. We used experimental plots that had been excluded from disturbance by cattle grazing during eight years. Plots were either planted with native trees (i. e. maximal intervention), or only excluded from disturbance (i. e. minimal intervention), and were compared with control conserved (remnants of original forest) and disturbed plots (where cattle is allowed to graze). We predicted (1) better body condition in spiders of conserved and restored sites, compared to disturbed sites, and (2) better body condition in plots with maximal intervention than in plots with minimal intervention. The first prediction was not supported in males or females, and the second prediction was only supported in females: body dry mass was higher in planted than in conserved plots for spiders of both sexes and also higher that in disturbed plots for males, suggesting that plantings are providing more resources. We discuss how different life histories and environmental pressures, such as food availability, parasitism, and competition for resources can explain our contrasting findings in male and female spiders. By studying animal physiology in restoration experiments it is possible to understand the mechanistic basis of ecological and evolutionary processes that determine success of ecological restoration. PMID:26226363

  10. 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.; Burris, J.A.

    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.

  11. Ecology of estuaries

    SciTech Connect

    Kennish, M.J. )

    1992-01-01

    Ecology of Estuaries: Anthropogenic Effects represents the most definitive and comprehensive source of reference information available on the human impact on estuarine ecosystems. The book discusses both acute and insidious pollution problems plaguing these coastal ecotones. It also provides a detailed examination of the deleterious and pervasive effects of human activities on biotic communities and sensitive habitat areas in estuaries. Specific areas covered include organic loading, oil pollution, polynuclear aromatic hydrocarbons, chlorinated hydrocarbons, heavy metals, dredging and dredge-spoil disposal, radionuclides, as well as other contaminants and processes. The diverse components of these anthropogenic influences are assembled in an organized framework and presented in a clear and concise style that will facilitate their understanding.

  12. Deleterious Mutations, Apparent Stabilizing Selection and the Maintenance of Quantitative Variation

    PubMed Central

    Kondrashov, A. S.; Turelli, M.

    1992-01-01

    Apparent stabilizing selection on a quantitative trait that is not causally connected to fitness can result from the pleiotropic effects of unconditionally deleterious mutations, because as N. Barton noted, ``... individuals with extreme values of the trait will tend to carry more deleterious alleles ....'' We use a simple model to investigate the dependence of this apparent selection on the genomic deleterious mutation rate, U; the equilibrium distribution of K, the number of deleterious mutations per genome; and the parameters describing directional selection against deleterious mutations. Unlike previous analyses, we allow for epistatic selection against deleterious alleles. For various selection functions and realistic parameter values, the distribution of K, the distribution of breeding values for a pleiotropically affected trait, and the apparent stabilizing selection function are all nearly Gaussian. The additive genetic variance for the quantitative trait is kQa(2), where k is the average number of deleterious mutations per genome, Q is the proportion of deleterious mutations that affect the trait, and a(2) is the variance of pleiotropic effects for individual mutations that do affect the trait. In contrast, when the trait is measured in units of its additive standard deviation, the apparent fitness function is essentially independent of Q and a(2); and ?, the intensity of selection, measured as the ratio of additive genetic variance to the ``variance'' of the fitness curve, is very close to s = U/k, the selection coefficient against individual deleterious mutations at equilibrium. Therefore, this model predicts appreciable apparent stabilizing selection if s exceeds about 0.03, which is consistent with various data. However, the model also predicts that ? must equal V(m)/V(G), the ratio of new additive variance for the trait introduced each generation by mutation to the standing additive variance. Most, although not all, estimates of this ratio imply apparent stabilizing selection weaker than generally observed. A qualitative argument suggests that even when direct selection is responsible for most of the selection observed on a character, it may be essentially irrelevant to the maintenance of variation for the character by mutation-selection balance. Simple experiments can indicate the fraction of observed stabilizing selection attributable to the pleiotropic effects of deleterious mutations. PMID:1427047

  13. 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

  14. Genetic variation in response to an indirect ecological effect

    PubMed Central

    Astles, Philip A; Moore, Allen J; Preziosi, Richard F

    2005-01-01

    Indirect ecological effects (IEEs) are widespread and often as strong as the phenotypic effects arising from direct interactions in natural communities. Indirect effects can influence competitive interactions, and are thought to be important selective forces. However, the extent that selection arising from IEEs results in long-term evolutionary change depends on genetic variation underlying the phenotypic response—that is, a genotype-by-IEE interaction. We provide the first data on genetic variation in the response of traits to an IEE, and illustrate how such genetic variation might be detected and analysed. We used a model tri-trophic system to investigate the effect of host plants on two populations of predatory ladybirds through a clonal aphid herbivore. A split-family experimental design allowed us to estimate the effects of aphid host plant on ladybird traits (IEE) and the extent of genetic variation in ladybird predators for response to these effects (genotype-by-indirect environmental effect interaction). We found significant genetic variation in the response of ladybird phenotypes to the indirect effect of host plant of their aphid prey, demonstrating the potential for evolutionary responses to selection arising from the prey host. PMID:16321778

  15. Biogeochemical and Ecological Effects of Nitrogen Deposition in Western North America

    NASA Astrophysics Data System (ADS)

    Fenn, M. E.

    2003-12-01

    The unique geographic, demographic, climatic and edaphic conditions of the West determine N deposition rates and biogeochemical and ecological responses to N deposition. In the western United States large regions are exposed to low N deposition levels with interspersed hotspots of elevated N deposition near urban areas or large agricultural emissions sources. Nitrogen emissions also contribute to ozone formation and regional haze and visibility impairment, the latter an effect that is observed in remote sites including several high profile national parks and wilderness areas. Recent studies suggest that N enrichment impacts are generally more important in western terrestrial systems than soil acidification effects. In the Pacific Northwest, California and Colorado sensitive organisms such as lichens and phytoplankton demonstrate deleterious biological effects with N deposition levels as low as 3-8 kg ha-1 yr-1. Increased streamwater nitrate export has been reported from southern California forests and chaparral catchments, high elevation watersheds in the Colorado Front Range, and in the most exposed regions of the southwestern Sierra Nevada. Evidence suggests that in some regions N deposition alters plant community composition, decreases mycorrhizal diversity, and also increases biomass accumulation, carbon allocation patterns and fire frequency. Several factors predispose Western semiarid ecosystems to N saturation as will be demonstrated by the San Bernardino Mountains case study (southern California). Edaphic conditions generally favor high nitrification rates relative to N mineralization. Nitrate from nitrification and atmospheric deposition accumulates in soil and on plant surfaces during prolonged dry periods. Under conditions of chronic N deposition, the N cycle becomes highly open in nature as excess N is exported in runoff and as gaseous emissions from soil. Actively nitrifying soils and temporal asynchrony between the period of plant N demand and nitrate availability are the key factors resulting in large N losses. As a result of this asynchrony, N limitation of tree growth occurs notwithstanding the advanced degree of N saturation. The combined effects of ozone and N deposition also cause major changes in plant carbon allocation and accumulation in the ecosystem, particularly under conditions of fire suppression.

  16. Parental effects in ecology and evolution: mechanisms, processes and implications

    PubMed Central

    Badyaev, Alexander V.; Uller, Tobias

    2009-01-01

    As is the case with any metaphor, parental effects mean different things to different biologists—from developmental induction of novel phenotypic variation to an evolved adaptation, and from epigenetic transference of essential developmental resources to a stage of inheritance and ecological succession. Such a diversity of perspectives illustrates the composite nature of parental effects that, depending on the stage of their expression and whether they are considered a pattern or a process, combine the elements of developmental induction, homeostasis, natural selection, epigenetic inheritance and historical persistence. Here, we suggest that by emphasizing the complexity of causes and influences in developmental systems and by making explicit the links between development, natural selection and inheritance, the study of parental effects enables deeper understanding of developmental dynamics of life cycles and provides a unique opportunity to explicitly integrate development and evolution. We highlight these perspectives by placing parental effects in a wider evolutionary framework and suggest that far from being only an evolved static outcome of natural selection, a distinct channel of transmission between parents and offspring, or a statistical abstraction, parental effects on development enable evolution by natural selection by reliably transferring developmental resources needed to reconstruct, maintain and modify genetically inherited components of the phenotype. The view of parental effects as an essential and dynamic part of an evolutionary continuum unifies mechanisms behind the origination, modification and historical persistence of organismal form and function, and thus brings us closer to a more realistic understanding of life's complexity and diversity. PMID:19324619

  17. 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…

  18. 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

  19. ENVIRONMENTAL EFFECTS OF INCREASED COAL UTILIZATION ECOLOGICAL EFFECTS OF GASEOUS EMISSIONS FROM COAL COMBUSTION

    EPA Science Inventory

    This report is provided for the 'Health and Environmental Effects of Coal Utilization' Committee which was created by the request of the DOE in response to the President's Environmental Message. It evaluates ecological environmental effects of gaseous emissions and aerosols of va...

  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. Improving the Assessment of the Outcome of Nonsynonymous SNVs with a Consensus Deleteriousness Score, Condel

    PubMed Central

    González-Pérez, Abel; López-Bigas, Nuria

    2011-01-01

    Several large ongoing initiatives that profit from next-generation sequencing technologies have driven—and in coming years will continue to drive—the emergence of long catalogs of missense single-nucleotide variants (SNVs) in the human genome. As a consequence, researchers have developed various methods and their related computational tools to classify these missense SNVs as probably deleterious or probably neutral polymorphisms. The outputs produced by each of these computational tools are of different natures and thus difficult to compare and integrate. Taking advantage of the possible complementarity between different tools might allow more accurate classifications. Here we propose an effective approach to integrating the output of some of these tools into a unified classification; this approach is based on a weighted average of the normalized scores of the individual methods (WAS). (In this paper, the approach is illustrated for the integration of five tools.) We show that this WAS outperforms each individual method in the task of classifying missense SNVs as deleterious or neutral. Furthermore, we demonstrate that this WAS can be used not only for classification purposes (deleterious versus neutral mutation) but also as an indicator of the impact of the mutation on the functionality of the mutant protein. In other words, it may be used as a deleteriousness score of missense SNVs. Therefore, we recommend the use of this WAS as a consensus deleteriousness score of missense mutations (Condel). PMID:21457909

  2. 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...

  3. A catalog of neutral and deleterious polymorphism in yeast.

    PubMed

    Doniger, Scott W; Kim, Hyun Seok; Swain, Devjanee; Corcuera, Daniella; Williams, Morgan; Yang, Shiaw-Pyng; Fay, Justin C

    2008-08-01

    The abundance and identity of functional variation segregating in natural populations is paramount to dissecting the molecular basis of quantitative traits as well as human genetic diseases. Genome sequencing of multiple organisms of the same species provides an efficient means of cataloging rearrangements, insertion, or deletion polymorphisms (InDels) and single-nucleotide polymorphisms (SNPs). While inbreeding depression and heterosis imply that a substantial amount of polymorphism is deleterious, distinguishing deleterious from neutral polymorphism remains a significant challenge. To identify deleterious and neutral DNA sequence variation within Saccharomyces cerevisiae, we sequenced the genome of a vineyard and oak tree strain and compared them to a reference genome. Among these three strains, 6% of the genome is variable, mostly attributable to variation in genome content that results from large InDels. Out of the 88,000 polymorphisms identified, 93% are SNPs and a small but significant fraction can be attributed to recent interspecific introgression and ectopic gene conversion. In comparison to the reference genome, there is substantial evidence for functional variation in gene content and structure that results from large InDels, frame-shifts, and polymorphic start and stop codons. Comparison of polymorphism to divergence reveals scant evidence for positive selection but an abundance of evidence for deleterious SNPs. We estimate that 12% of coding and 7% of noncoding SNPs are deleterious. Based on divergence among 11 yeast species, we identified 1,666 nonsynonymous SNPs that disrupt conserved amino acids and 1,863 noncoding SNPs that disrupt conserved noncoding motifs. The deleterious coding SNPs include those known to affect quantitative traits, and a subset of the deleterious noncoding SNPs occurs in the promoters of genes that show allele-specific expression, implying that some cis-regulatory SNPs are deleterious. Our results show that the genome sequences of both closely and distantly related species provide a means of identifying deleterious polymorphisms that disrupt functionally conserved coding and noncoding sequences. PMID:18769710

  4. 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 ...

  5. 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...

  6. 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

  7. A computational approach to determine susceptibility to cancer by evaluating the deleterious effect of nsSNP in XRCC1 gene on binding interaction of XRCC1 protein with ligase III.

    PubMed

    Singh, Preety Kadian; Mistry, Kinnari N

    2016-01-15

    Several reports suggest that non-synonymous single nucleotide polymorphisms affect the function of XRCC1 which impairs DNA repair capacity and thus increases risk to diseases like cancer. In our study, we predicted the most damaging nsSNPs using a computational approach and analysed its functional impact on the XRCC1 and LIG3 interaction. SNP rs2307166 was predicted to be deleterious using eight software programs: SIFT, PolyPhen, PANTHER, PhD-SNP, nsSNPAnalyzer, SNPS&GO, SNAP and I-Mutant. Protein structural analysis was performed using Swiss PDB viewer, and PyMOL. Xenoview was used for molecular dynamic simulation and energy minimisation. Finally, PatchDock and FireDock were used to analyse the interactions of XRCC1 and LIG3. By comparing the results we found that the mutant protein has less binding energy and the interacting amino acids than native protein. In silico analysis predicted rs2307166 to be more damaging than three other extensively studied SNPs. Identification of this SNP will help in determining the susceptibility of the individual to cancer, their prognosis and further treatment. PMID:26449312

  8. Extraordinary Sex Ratios: Cultural Effects on Ecological Consequences

    PubMed Central

    Molnr, 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 Fishers 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

  9. Bottlenecks and selective sweeps during domestication have increased deleterious genetic variation in dogs.

    PubMed

    Marsden, Clare D; Ortega-Del Vecchyo, Diego; O'Brien, Dennis P; Taylor, Jeremy F; Ramirez, Oscar; Vilà, Carles; Marques-Bonet, Tomas; Schnabel, Robert D; Wayne, Robert K; Lohmueller, Kirk E

    2016-01-01

    Population bottlenecks, inbreeding, and artificial selection can all, in principle, influence levels of deleterious genetic variation. However, the relative importance of each of these effects on genome-wide patterns of deleterious variation remains controversial. Domestic and wild canids offer a powerful system to address the role of these factors in influencing deleterious variation because their history is dominated by known bottlenecks and intense artificial selection. Here, we assess genome-wide patterns of deleterious variation in 90 whole-genome sequences from breed dogs, village dogs, and gray wolves. We find that the ratio of amino acid changing heterozygosity to silent heterozygosity is higher in dogs than in wolves and, on average, dogs have 2-3% higher genetic load than gray wolves. Multiple lines of evidence indicate this pattern is driven by less efficient natural selection due to bottlenecks associated with domestication and breed formation, rather than recent inbreeding. Further, we find regions of the genome implicated in selective sweeps are enriched for amino acid changing variants and Mendelian disease genes. To our knowledge, these results provide the first quantitative estimates of the increased burden of deleterious variants directly associated with domestication and have important implications for selective breeding programs and the conservation of rare and endangered species. Specifically, they highlight the costs associated with selective breeding and question the practice favoring the breeding of individuals that best fit breed standards. Our results also suggest that maintaining a large population size, rather than just avoiding inbreeding, is a critical factor for preventing the accumulation of deleterious variants. PMID:26699508

  10. Purging Deleterious Mutations under Self Fertilization: Paradoxical Recovery in Fitness with Increasing Mutation Rate in Caenorhabditis elegans

    PubMed Central

    Morran, Levi T.; Ohdera, Aki H.; Phillips, Patrick C.

    2010-01-01

    Background The accumulation of deleterious mutations can drastically reduce population mean fitness. Self-fertilization is thought to be an effective means of purging deleterious mutations. However, widespread linkage disequilibrium generated and maintained by self-fertilization is predicted to reduce the efficacy of purging when mutations are present at multiple loci. Methodology/Principal Findings We tested the ability of self-fertilizing populations to purge deleterious mutations at multiple loci by exposing obligately self-fertilizing populations of Caenorhabditis elegans to a range of elevated mutation rates and found that mutations accumulated, as evidenced by a reduction in mean fitness, in each population. Therefore, purging in obligate selfing populations is overwhelmed by an increase in mutation rate. Surprisingly, we also found that obligate and predominantly self-fertilizing populations exposed to very high mutation rates exhibited consistently greater fitness than those subject to lesser increases in mutation rate, which contradicts the assumption that increases in mutation rate are negatively correlated with fitness. The high levels of genetic linkage inherent in self-fertilization could drive this fitness increase. Conclusions Compensatory mutations can be more frequent under high mutation rates and may alleviate a portion of the fitness lost due to the accumulation of deleterious mutations through epistatic interactions with deleterious mutations. The prolonged maintenance of tightly linked compensatory and deleterious mutations facilitated by self-fertilization may be responsible for the fitness increase as linkage disequilibrium between the compensatory and deleterious mutations preserves their epistatic interaction. PMID:21217820

  11. 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 Glinica 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.

  12. Computational evaluation of cellular metabolic costs successfully predicts genes whose expression is deleterious

    PubMed Central

    Wagner, Allon; Zarecki, Raphy; Reshef, Leah; Gochev, Camelia; Sorek, Rotem; Gophna, Uri; Ruppin, Eytan

    2013-01-01

    Gene suppression and overexpression are both fundamental tools in linking genotype to phenotype in model organisms. Computational methods have proven invaluable in studying and predicting the deleterious effects of gene deletions, and yet parallel computational methods for overexpression are still lacking. Here, we present Expression-Dependent Gene Effects (EDGE), an in silico method that can predict the deleterious effects resulting from overexpression of either native or foreign metabolic genes. We first test and validate EDGE’s predictive power in bacteria through a combination of small-scale growth experiments that we performed and analysis of extant large-scale datasets. Second, a broad cross-species analysis, ranging from microorganisms to multiple plant and human tissues, shows that genes that EDGE predicts to be deleterious when overexpressed are indeed typically down-regulated. This reflects a universal selection force keeping the expression of potentially deleterious genes in check. Third, EDGE-based analysis shows that cancer genetic reprogramming specifically suppresses genes whose overexpression impedes proliferation. The magnitude of this suppression is large enough to enable an almost perfect distinction between normal and cancerous tissues based solely on EDGE results. We expect EDGE to advance our understanding of human pathologies associated with up-regulation of particular transcripts and to facilitate the utilization of gene overexpression in metabolic engineering. PMID:24198337

  13. 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…

  14. Deleterious oral habits in children with hearing impairment

    PubMed Central

    SUHANI, RALUCA DIANA; SUHANI, MIHAI FLAVIU; MUNTEAN, ALEXANDRINA; MESAROS, MICHAELA; BADEA, MINDRA EUGENIA

    2015-01-01

    Background and aims Deleterious oral habits represent a serious public health issue. The information available about this problem in children with hearing impairment is insufficient. The purpose of this study was to investigate the prevalence of deleterious oral habits among children with hearing impairment and comparing results against children without hearing impairment. Method This epidemiological study was carried out in a sample size of 315 children. We used a random sampling technique that included 150 children with hearing impairment and 165 without hearing impairment. All subjects were submitted to a clinical examination. The parents/legal guardians were asked to complete a questionnaire regarding the deleterious habits of their children. Results The data collected indicated a higher prevalence of deleterious oral habits among children with hearing impairment: 53.3% as opposed to 40.6% among children without hearing impairment. There was a higher incidence of malocclusion in children with hearing impairment (79.3%) compared to children without hearing impairment (57%). Conclusions This study highlighted the need to establish protocols for preventive orthodontic treatment at an early age, in order to reduce the deleterious oral habits and prevent malocclusion. Dental institutions/clinicians need to implement oral care programs including proper oral education aiming to promote oral health. PMID:26609277

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. Obstruction of adaptation in diploids by recessive, strongly deleterious alleles

    PubMed Central

    Assaf, Zoe June; Petrov, Dmitri A.; Blundell, Jamie R.

    2015-01-01

    Recessive deleterious mutations are common, causing many genetic disorders in humans and producing inbreeding depression in the majority of sexually reproducing diploids. The abundance of recessive deleterious mutations in natural populations suggests they are likely to be present on a chromosome when a new adaptive mutation occurs, yet the dynamics of recessive deleterious hitchhikers and their impact on adaptation remains poorly understood. Here we model how a recessive deleterious mutation impacts the fate of a genetically linked dominant beneficial mutation. The frequency trajectory of the adaptive mutation in this case is dramatically altered and results in what we have termed a “staggered sweep.” It is named for its three-phased trajectory: (i) Initially, the two linked mutations have a selective advantage while rare and will increase in frequency together, then (ii), at higher frequencies, the recessive hitchhiker is exposed to selection and can cause a balanced state via heterozygote advantage (the staggered phase), and (iii) finally, if recombination unlinks the two mutations, then the beneficial mutation can complete the sweep to fixation. Using both analytics and simulations, we show that strongly deleterious recessive mutations can substantially decrease the probability of fixation for nearby beneficial mutations, thus creating zones in the genome where adaptation is suppressed. These mutations can also significantly prolong the number of generations a beneficial mutation takes to sweep to fixation, and cause the genomic signature of selection to resemble that of soft or partial sweeps. We show that recessive deleterious variation could impact adaptation in humans and Drosophila. PMID:25941393

  20. Effect of localization on the stability of mutualistic ecological networks

    PubMed Central

    Suweis, Samir; Grilli, Jacopo; Banavar, Jayanth R.; Allesina, Stefano; Maritan, Amos

    2015-01-01

    The relationships between the core–periphery architecture of the species interaction network and the mechanisms ensuring the stability in mutualistic ecological communities are still unclear. In particular, most studies have focused their attention on asymptotic resilience or persistence, neglecting how perturbations propagate through the system. Here we develop a theoretical framework to evaluate the relationship between the architecture of the interaction networks and the impact of perturbations by studying localization, a measure describing the ability of the perturbation to propagate through the network. We show that mutualistic ecological communities are localized, and localization reduces perturbation propagation and attenuates its impact on species abundance. Localization depends on the topology of the interaction networks, and it positively correlates with the variance of the weighted degree distribution, a signature of the network topological heterogeneity. Our results provide a different perspective on the interplay between the architecture of interaction networks in mutualistic communities and their stability. PMID:26674106

  1. Effect of localization on the stability of mutualistic ecological networks.

    PubMed

    Suweis, Samir; Grilli, Jacopo; Banavar, Jayanth R; Allesina, Stefano; Maritan, Amos

    2015-01-01

    The relationships between the core-periphery architecture of the species interaction network and the mechanisms ensuring the stability in mutualistic ecological communities are still unclear. In particular, most studies have focused their attention on asymptotic resilience or persistence, neglecting how perturbations propagate through the system. Here we develop a theoretical framework to evaluate the relationship between the architecture of the interaction networks and the impact of perturbations by studying localization, a measure describing the ability of the perturbation to propagate through the network. We show that mutualistic ecological communities are localized, and localization reduces perturbation propagation and attenuates its impact on species abundance. Localization depends on the topology of the interaction networks, and it positively correlates with the variance of the weighted degree distribution, a signature of the network topological heterogeneity. Our results provide a different perspective on the interplay between the architecture of interaction networks in mutualistic communities and their stability. PMID:26674106

  2. Sex ratio variation shapes the ecological effects of a globally introduced freshwater fish.

    PubMed

    Fryxell, David C; Arnett, Heather A; Apgar, Travis M; Kinnison, Michael T; Palkovacs, Eric P

    2015-10-22

    Sex ratio and sexual dimorphism have long been of interest in population and evolutionary ecology, but consequences for communities and ecosystems remain untested. Sex ratio could influence ecological conditions whenever sexual dimorphism is associated with ecological dimorphism in species with strong ecological interactions. We tested for ecological implications of sex ratio variation in the sexually dimorphic western mosquitofish, Gambusia affinis. This species causes strong pelagic trophic cascades and exhibits substantial variation in adult sex ratios. We found that female-biased populations induced stronger pelagic trophic cascades compared with male-biased populations, causing larger changes to key community and ecosystem responses, including zooplankton abundance, phytoplankton abundance, productivity, pH and temperature. The magnitude of such effects indicates that sex ratio is important for mediating the ecological role of mosquitofish. Because both sex ratio variation and sexual dimorphism are common features of natural populations, our findings should encourage broader consideration of the ecological significance of sex ratio variation in nature, including the relative contributions of various sexually dimorphic traits to these effects. PMID:26490793

  3. [Application and effectiveness of soil bioengineering in ecological restoration of stream bank].

    PubMed

    Li, Xiaoping; Zhang, Liquan

    2006-09-01

    Soil bioengineering is a kind of engineering by using living plant materials to construct the structures with some engineering and ecological functions, which can provide an effective means for the slope stabilization and site restoration of stream banks. In this paper, the principles of soil bioengineering, basic planting methods, live stakes, live fascines, brush layering, and integrated technologies were discussed in brief, and the first demo project of soil engineering in ecological restoration of stream bank in our country was introduced. After 10-month project implementation, significant effectiveness was obtained on slope stability, habitat improvement, and ecological restoration of stream banks. It was concluded that the approach could be widely applied in ecological restoration of all kinds of slopes in China. PMID:17147185

  4. 21 CFR 109.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Added poisonous or deleterious substances. 109.6 Section 109.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION UNAVOIDABLE CONTAMINANTS IN FOOD FOR HUMAN CONSUMPTION AND...

  5. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Added poisonous or deleterious substances. 509.6 Section 509.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS UNAVOIDABLE CONTAMINANTS IN ANIMAL FOOD AND...

  6. Prevention of deleterious deposits in a coal liquefaction system

    DOEpatents

    Carr, Norman L.; Prudich, Michael E.; King, Jr., William E.; Moon, William G.

    1984-07-03

    A process for preventing the formation of deleterious coke deposits on the walls of coal liquefaction reactor vessels involves passing hydrogen and a feed slurry comprising feed coal and recycle liquid solvent to a coal liquefaction reaction zone while imparting a critical mixing energy of at least 3500 ergs per cubic centimeter of reaction zone volume per second to the reacting slurry.

  7. 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...

  8. 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

  9. 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

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

    SciTech Connect

    Pardal, J.M.

    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.

  11. 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 ecologicalsoilgeomorphic 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.

  12. Hitchhiking of Deleterious Alleles and the Cost of Adaptation in Partially Selfing Species

    PubMed Central

    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

  13. 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

  14. Prevalence of deleterious ATM germline mutations in gastric cancer patients.

    PubMed

    Huang, Dong-Sheng; Tao, Hou-Quan; He, Xu-Jun; Long, Ming; Yu, Sheng; Xia, Ying-Jie; Wei, Zhang; Xiong, Zikai; Jones, Sian; He, Yiping; Yan, Hai; Wang, Xiaoyue

    2015-12-01

    Besides CDH1, few hereditary gastric cancer predisposition genes have been previously reported. In this study, we discovered two germline ATM mutations (p.Y1203fs and p.N1223S) in a Chinese family with a history of gastric cancer by screening 83 cancer susceptibility genes. Using a published exome sequencing dataset, we found deleterious germline mutations of ATM in 2.7% of 335 gastric cancer patients of different ethnic origins. The frequency of deleterious ATM mutations in gastric cancer patients is significantly higher than that in general population (p=0.0000435), suggesting an association of ATM mutations with gastric cancer predisposition. We also observed biallelic inactivation of ATM in tumors of two gastric cancer patients. Further evaluation of ATM mutations in hereditary gastric cancer will facilitate genetic testing and risk assessment. PMID:26506520

  15. Prevalence of deleterious ATM germline mutations in gastric cancer patients

    PubMed Central

    He, Xu-Jun; Long, Ming; Yu, Sheng; Xia, Ying-Jie; Wei, Zhang; Xiong, Zikai; Jones, Sian; He, Yiping; Yan, Hai; Wang, Xiaoyue

    2015-01-01

    Besides CDH1, few hereditary gastric cancer predisposition genes have been previously reported. In this study, we discovered two germline ATM mutations (p.Y1203fs and p.N1223S) in a Chinese family with a history of gastric cancer by screening 83 cancer susceptibility genes. Using a published exome sequencing dataset, we found deleterious germline mutations of ATM in 2.7% of 335 gastric cancer patients of different ethnic origins. The frequency of deleterious ATM mutations in gastric cancer patients is significantly higher than that in general population (p=0.0000435), suggesting an association of ATM mutations with gastric cancer predisposition. We also observed biallelic inactivation of ATM in tumors of two gastric cancer patients. Further evaluation of ATM mutations in hereditary gastric cancer will facilitate genetic testing and risk assessment. PMID:26506520

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

    SciTech Connect

    Peck, J.R.

    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.

  17. Simulation of deleterious processes in a static-cell diode pumped alkali laser

    NASA Astrophysics Data System (ADS)

    Oliker, Benjamin Q.; Haiducek, John D.; Hostutler, David A.; Pitz, Greg A.; Rudolph, Wolfgang; Madden, Timothy J.

    2014-02-01

    The complex interactions in a diode pumped alkali laser (DPAL) gain cell provide opportunities for multiple deleterious processes to occur. Effects that may be attributable to deleterious processes have been observed experimentally in a cesium static-cell DPAL at the United States Air Force Academy [B.V. Zhdanov, J. Sell, R.J. Knize, "Multiple laser diode array pumped Cs laser with 48 W output power," Electronics Letters, 44, 9 (2008)]. The power output in the experiment was seen to go through a "roll-over"; the maximum power output was obtained with about 70 W of pump power, then power output decreased as the pump power was increased beyond this point. Research to determine the deleterious processes that caused this result has been done at the Air Force Research Laboratory utilizing physically detailed simulation. The simulations utilized coupled computational fluid dynamics (CFD) and optics solvers, which were three-dimensional and time-dependent. The CFD code used a cell-centered, conservative, finite-volume discretization of the integral form of the Navier-Stokes equations. It included thermal energy transport and mass conservation, which accounted for chemical reactions and state kinetics. Optical models included pumping, lasing, and fluorescence. The deleterious effects investigated were: alkali number density decrease in high temperature regions, convective flow, pressure broadening and shifting of the absorption lineshape including hyperfine structure, radiative decay, quenching, energy pooling, off-resonant absorption, Penning ionization, photoionization, radiative recombination, three-body recombination due to free electron and buffer gas collisions, ambipolar diffusion, thermal aberration, dissociative recombination, multi-photon ionization, alkali-hydrocarbon reactions, and electron impact ionization.

  18. 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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A legacy effect refers to the impact that previous conditions have on current processes or properties. Ecological legacies in drylands result from feedbacks among biotic, soil, and geomorphic processes that operate at multiple spatial and temporal scales. Legacy effects depend on (1) the magnitude o...

  20. [Scale effect of Li-Xiang Railway construction impact on landscape pattern and its ecological risk].

    PubMed

    Wang, De-zhi; Qiu, Peng-hua; Fang, Yuan-min

    2015-08-01

    As a large corridor project, plateau railway has multiple points and passes various sensitive environments along the railway. The determination of the scope of impact on ecological environment from railway construction is often controversial in ecological impact assessment work. Taking the Tangbu-Jiantang section of Li-Xiang Railway as study object, and using present land use map (1:10000) in 2012 and DEM as data sources, corridor cutting degree index ( CCI) and cumulative effect index of corridor (CCEI) were established by topology, buffer zone and landscape metrics methods. Besides, the ecological risk index used for railway construction was improved. By quantitative analysis of characteristics of the spatio-temporal change of landscape pattern and its evolution style at different spatial scales before and after railway construction, the most appropriate evaluation scale of the railway was obtained. Then the characteristics of the spatio-temporal variation of ecological risk within this scale before and after railway construction were analyzed. The results indicated that the cutting model and degree of railway corridor to various landscape types could be effectively reflected by CCI, and the exposure and harm relations between risk sources and risk receptors of railway can be measured by CCEI. After the railway construction, the railway corridor would cause a great deal of middle cutting effect on the landscape along the railroad, which would influence wood land and grassland landscape most greatly, while would cause less effect of edge cutting and internal cutting. Landscape indices within the 600 m buffer zone demonstrated the most obvious scale effect, therefore, the 600 m zone of the railway was set as the most suitable range of ecological impact assessment. Before railway construction, the low ecological risk level covered the biggest part of the 600 m assessment zone. However, after the railway construction, the ecological risk increased significantly, and the most part of the study area was at the moderate ecological risk level. The ecological risk presented ring-shaped and multi-kernel patterns, and was lower in the southern part than in the northern part of the study area. PMID:26685614

  1. 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.

  2. Exploring the effects of ecological activities during exposure to optical prisms in healthy individuals

    PubMed Central

    Fortis, Paola; Ronchi, Roberta; Calzolari, Elena; Gallucci, Marcello; Vallar, Giuseppe

    2013-01-01

    Prism adaptation improves a wide range of manifestations of left spatial neglect in right-brain-damaged patients. The typical paradigm consists in repeated pointing movements to visual targets, while patients wear prism goggles that displace the visual scene rightwards. Recently, we demonstrated the efficacy of a novel adaptation procedure, involving a variety of every-day visuo-motor activities. This ecological procedure proved to be as effective as the repetitive pointing adaptation task in ameliorating symptoms of spatial neglect, and was better tolerated by patients. However, the absence of adaptation and aftereffects measures for the ecological treatment did not allow for a full comparison of the two procedures. This is important in the light of recent findings showing that the magnitude of prism-induced aftereffects may predict recovery from spatial neglect. Here, we investigated prism-induced adaptation and aftereffects after ecological and pointing adaptation procedures. Forty-eight neurologically healthy participants (young and aged groups) were exposed to rightward shifting prisms while they performed the ecological or the pointing procedures, in separate days. Before and after prism exposure, participants performed proprioceptive, visual, and visual-proprioceptive tasks to assess prism-induced aftereffects. Participants adapted to the prisms during both procedures. Importantly, the ecological procedure induced greater aftereffects in the proprioceptive task (for both the young and the aged groups) and in the visual-proprioceptive task (young group). A similar trend was found for the visual task in both groups. Finally, participants rated the ecological procedure as more pleasant, less monotonous, and more sustainable than the pointing procedure. These results qualify ecological visuo-motor activities as an effective prism-adaptation procedure, suitable for the rehabilitation of spatial neglect. PMID:23408549

  3. Human effects on ecological connectivity in aquatic ecosystems: Integrating scientific approaches to support management and mitigation.

    PubMed

    Crook, David A; Lowe, Winsor H; Allendorf, Frederick W; Erős, Tibor; Finn, Debra S; Gillanders, Bronwyn M; Hadwen, Wade L; Harrod, Chris; Hermoso, Virgilio; Jennings, Simon; Kilada, Raouf W; Nagelkerken, Ivan; Hansen, Michael M; Page, Timothy J; Riginos, Cynthia; Fry, Brian; Hughes, Jane M

    2015-11-15

    Understanding the drivers and implications of anthropogenic disturbance of ecological connectivity is a key concern for the conservation of biodiversity and ecosystem processes. Here, we review human activities that affect the movements and dispersal of aquatic organisms, including damming of rivers, river regulation, habitat loss and alteration, human-assisted dispersal of organisms and climate change. Using a series of case studies, we show that the insight needed to understand the nature and implications of connectivity, and to underpin conservation and management, is best achieved via data synthesis from multiple analytical approaches. We identify four key knowledge requirements for progressing our understanding of the effects of anthropogenic impacts on ecological connectivity: autecology; population structure; movement characteristics; and environmental tolerance/phenotypic plasticity. Structuring empirical research around these four broad data requirements, and using this information to parameterise appropriate models and develop management approaches, will allow for mitigation of the effects of anthropogenic disturbance on ecological connectivity in aquatic ecosystems. PMID:25917446

  4. 75 FR 8338 - EPA Science Advisory Board Staff Office Notification of a Meeting of the Ecological Effects...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... overall validity and utility of the estimated changes in ecological effects from air pollution between the... a public meeting of the Ecological Effects Subcommittee (EES) of the Advisory Council on Clean Air... effects of modeled air quality scenarios developed to support the Second Section 812 Benefit-Cost...

  5. Deleterious Alleles in the Human Genome Are on Average Younger Than Neutral Alleles of the Same Frequency

    PubMed Central

    Kiezun, Adam; Pulit, Sara L.; Francioli, Laurent C.; van Dijk, Freerk; Swertz, Morris; Boomsma, Dorret I.; van Duijn, Cornelia M.; Slagboom, P. Eline; van Ommen, G. J. B.; Wijmenga, Cisca; de Bakker, Paul I. W.; Sunyaev, Shamil R.

    2013-01-01

    Large-scale population sequencing studies provide a complete picture of human genetic variation within the studied populations. A key challenge is to identify, among the myriad alleles, those variants that have an effect on molecular function, phenotypes, and reproductive fitness. Most non-neutral variation consists of deleterious alleles segregating at low population frequency due to incessant mutation. To date, studies characterizing selection against deleterious alleles have been based on allele frequency (testing for a relative excess of rare alleles) or ratio of polymorphism to divergence (testing for a relative increase in the number of polymorphic alleles). Here, starting from Maruyama's theoretical prediction (Maruyama T (1974), Am J Hum Genet USA 6:669–673) that a (slightly) deleterious allele is, on average, younger than a neutral allele segregating at the same frequency, we devised an approach to characterize selection based on allelic age. Unlike existing methods, it compares sets of neutral and deleterious sequence variants at the same allele frequency. When applied to human sequence data from the Genome of the Netherlands Project, our approach distinguishes low-frequency coding non-synonymous variants from synonymous and non-coding variants at the same allele frequency and discriminates between sets of variants independently predicted to be benign or damaging for protein structure and function. The results confirm the abundance of slightly deleterious coding variation in humans. PMID:23468643

  6. 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.

  7. Effect of Computer-Assisted Instruction on Secondary School Students' Achievement in Ecological Concepts

    ERIC Educational Resources Information Center

    Nkemdilim, Egbunonu Roseline; Okeke, Sam O. C.

    2014-01-01

    This study investigated the effects of computer-assisted instruction (CAI) on students' achievement in ecological concepts. Quasi-experimental design, specifically the pre-test post test non-equivalent control group design was adopted. The sample consisted of sixty-six (66) senior secondary year two (SS II) biology students, drawn from two…

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

    ERIC Educational Resources Information Center

    etin, Glcan; Ertepinar, Hamide; Geban, mer

    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

  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. The Effect of Environmental Education on the Ecological Literacy of First-Year College Students

    ERIC Educational Resources Information Center

    Bruyere, Brett L.

    2008-01-01

    This article assesses the viability of a value-attitude-behavior hierarchy within the context of four environmentally responsible behavior types of first-year college students. The research also studies the effect of knowledge on attitude and behavior, and discusses the implications of the results for understanding the ecological literacy of

  11. Effect of Computer-Assisted Instruction on Secondary School Students' Achievement in Ecological Concepts

    ERIC Educational Resources Information Center

    Nkemdilim, Egbunonu Roseline; Okeke, Sam O. C.

    2014-01-01

    This study investigated the effects of computer-assisted instruction (CAI) on students' achievement in ecological concepts. Quasi-experimental design, specifically the pre-test post test non-equivalent control group design was adopted. The sample consisted of sixty-six (66) senior secondary year two (SS II) biology students, drawn from two

  12. Community-Based Eco-Education: Sound Ecology and Effective Education.

    ERIC Educational Resources Information Center

    Niesenbaum, Richard A.; Gorka, Barbara

    2001-01-01

    Reports on the development of a college-level eco-educational course that attempts to capitalize on the ecological and educational strengths of ecotourism by establishing a partnership with a local community. Makes suggestions for establishing community partnerships for effective international eco-educational program development. (Contains 15

  13. 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.

  14. 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…

  15. Community-Based Eco-Education: Sound Ecology and Effective Education.

    ERIC Educational Resources Information Center

    Niesenbaum, Richard A.; Gorka, Barbara

    2001-01-01

    Reports on the development of a college-level eco-educational course that attempts to capitalize on the ecological and educational strengths of ecotourism by establishing a partnership with a local community. Makes suggestions for establishing community partnerships for effective international eco-educational program development. (Contains 15…

  16. 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...

  17. INFLUENCE OF SIZE ON FATE AND ECOLOGICAL EFFECTS OF KEPONE IN PHYSICAL MODELS

    EPA Science Inventory

    Three different sizes of marine microcosms were used to study the influence of two features of spatial scale on the chemical fate and ecological effects of the pesticide Kepone. ncreasing the size of microcosms reduced the ratio of wall surface area to volume of contained sea wat...

  18. Pantoea agglomerans: a mysterious bacterium of evil and good. Part II. Deleterious effects: Dust-borne endotoxins and allergens - focus on grain dust, other agricultural dusts and wood dust.

    PubMed

    Dutkiewicz, Jacek; Mackiewicz, Barbara; Lemieszek, Marta Kinga; Golec, Marcin; Skórska, Czesława; Góra-Florek, Anna; Milanowski, Janusz

    2016-03-01

    Pantoea agglomerans, a Gram-negative bacterium developing in a variety of plants as epiphyte or endophyte is particularly common in grain and grain dust, and has been identified by an interdisciplinary group from Lublin, eastern Poland, as a causative agent of work-related diseases associated with exposure to grain dust and other agricultural dusts. The concentration of P. agglomerans in grain as well as in the settled grain and flour dust was found to be high, ranging from 10(4) -10(8) CFU/g, while in the air polluted with grain or flour dust it ranged from 10(3) -10(5) CFU/m(3) and formed 73.2-96% of the total airborne Gram-negative bacteria. The concentration of P. agglomerans was also relatively high in the air of the facilities processing herbs and other plant materials, while it was lower in animal farms and in wood processing facilities. Pantoea agglomerans produces a biologically-potent endotoxin (cell wall lipopolysaccharide, LPS). The significant part of this endotoxin occurs in dusts in the form of virus-sized globular nanoparticles measuring 10-50 nm that could be described as the 'endotoxin super-macromolecules'. A highly significant relationship was found (R=0.804, P=0.000927) between the concentration of the viable P. agglomerans in the air of various agricultural and wood industry settings and the concentration of bacterial endotoxin in the air, as assessed by the Limulus test. Although this result may be interfered by the presence of endotoxin produced by other Gram-negative species, it unequivocally suggests the primary role of the P. agglomerans endotoxin as an adverse agent in the agricultural working environment, causing toxic pneumonitis (ODTS). Numerous experiments by the inhalation exposure of animals to various extracts of P. agglomerans strains isolated from grain dust, including endotoxin isolated with trichloroacetic acid (LPS-TCA), endotoxin nanoparticles isolated in sucrose gradient (VECN), and mixture of proteins and endotoxin obtained by extraction of bacterial mass in saline (CA-S), showed the ability of these extracts to evoke inflammatory and fibrotic changes in the lungs, to stimulate alveolar macrophages to produce superoxide anion (O2(-) ), interleukin-1 (IL-1) and chemotactic factors for other macrophages and neutrophils, and to increase the pulmonary concentrations of toll-like receptors and chemokines. The most potent properties showed the CA-S which may be attributed to the allergenic properties of P. agglomerans proteins enhanced by the presence of the autologous endotoxin. The results of these experiments are in accord with the clinical studies which revealed a high reactivity of the agricultural and grain industry workers to allergenic extracts of P. agglomerans, and the presence in these populations of hypersensitivity pneumonitis and asthma cases caused by this bacterium. P. agglomerans has been also identified as a potential causative agent of allergic dermatitis in farmers and of allergic pulmonary disorders in cattle. In conclusion, similar to the cotton industry, also in the grain industry and in agriculture, Pantoea agglomerans should be regarded as one of the major causative agents of work-related diseases, caused by the adverse effects of protein allergens and endotoxin produced by this bacterium. PMID:27007514

  19. Effect of new antimicrobial agents on the ecological balance of human microflora.

    PubMed

    Rashid, Mamun-Ur; Weintraub, Andrej; Nord, Carl Erik

    2012-04-01

    The human normal microflora is relatively stable at each ecological habitat under normal circumstances and acts as a barrier against colonization by potentially pathogenic microorganisms and against overgrowth of already present opportunistic microorganisms. Administration of antimicrobial agents causes disturbances in the ecological balance between the host and the normal microflora. The risk of emergence and spread of resistant strains between patients and dissemination of resistant determinants between microorganisms is reduced if colonization resistance is not disturbed by antimicrobial agents. In this article, the potential ecological effects of administration of new antimicrobial agents on the intestinal and oropharyngeal microflora are summarized. The review is based on clinical studies published during the past 10 years. PMID:22155131

  20. 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

  1. 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...

  2. Environmental chemical mixtures: Assessing ecological exposure and effects in streams

    EPA Science Inventory

    This product is a USGS fact sheet that describes a collaborative effort between USGS and US EPA to characterize exposures to chemical mixtures and associated biological effects for a diverse range of US streams representing varying watershed size, land-use patterns, and ecotypes.

  3. ECOLOGICAL EFFECTS OF AEROSOL DRIFT FROM A SALTWATER COOLING SYSTEM

    EPA Science Inventory

    The local terrestrial effects of salt aerosol drift from powered spray modules and a mechanical draft cooling tower at Turkey Point, Florida were evaluated through field and controlled exposure studies. Indigenous vegetation, soil and fresh water were sampled over a year long per...

  4. 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...

  5. The Ecological Effects in Acculturation of Puerto Rican Migrants.

    ERIC Educational Resources Information Center

    Lopez-Ramirez, Norma Iris

    Various studies discuss the influences on and effects of the process of adjustment to a new environment among Puerto Rican migrants to the United States mainland. In confronting cultural differences, Puerto Ricans may experience culture shock and identity problems and suffer disassociation leading to schizophrenia and hysteria, stress,

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

    PubMed

    Boening, D W

    2000-06-01

    Mercury at low concentrations represents a major hazard to microorganisms. Inorganic mercury has been reported to produce harmful effects at 5 microg/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 are affected by mercury in water at concentrations of 1 mg/l for inorganic mercury and at much lower concentrations of organic mercury. Aquatic invertebrates widely vary in their susceptibility to mercury. In general, organisms in the larval stage are most sensitive. Methyl mercury in fish is caused by bacterial methylation of inorganic mercury, either in the environment or in bacteria associated with fish gills or gut. In aquatic matrices, mercury toxicity is affected by temperature, salinity, dissolved oxygen and water hardness. A wide variety of physiological, reproductive and biochemical abnormalities have been reported in fish exposed to sublethal concentrations of mercury. Birds fed inorganic mercury show a reduction in food intake and consequent poor growth. Other (more subtle) effects in avian receptors have been reported (i.e., increased enzyme production, decreased cardiovascular function, blood parameter changes, immune response, kidney function and structure, and behavioral changes). The form of retained mercury in birds is more variable and depends on species, target organ and geographical site. With few exceptions, terrestrial plants (woody plants in particular) are generally insensitive to the harmful effects of mercury compounds. PMID:10789973

  7. Ecological toxicology and human health effects of heptachlor.

    PubMed

    Fendick, E A; Mather-Mihaich, E; Houck, K A; St Clair, M B; Faust, J B; Rockwell, C H; Owens, M

    1990-01-01

    The chlorinated cyclodiene heptachlor was registered in 1952 as an agricultural and domestic insecticide. By early 1984, registration for all purposes, except subterranean termite control and for limited use in the control of fire ants, had been cancelled. This restriction of use arose primarily from concerns over the environmental persistance and bioaccumulation potential of the organochlorine pesticides. Currently, sale of heptachlor has been voluntarily suspended over questions about its carcinogenic potential, and the absence of safe and effective application methods. As a persistent organochlorine pesticide, heptachlor residues are detected in all components of the environment. In historical use, heptachlor was directly applied to terrestrial systems, while air and water were secondarily contaminated via volatilization and land run-off, respectively. Within each environmental compartment, heptachlor undergoes a variety of metabolic and abiotic transformations. In vivo studies indicate that heptachlor epoxide is the predominant metabolite, formed as a product of the mixed-function oxidase system, while 1-hydroxychlordene is the major soil metabolite. For quantification, heptachlor and its metabolites are extracted from air, soil and sediment, water, or biological materials using various organic solvents and analyzed by gas chromatography or thin-layer chromatography. Residue reports comprise most of the literature concerning the effects of heptachlor on the biota. In many such reports, toxic effects cannot be conclusively attributed to heptachlor exposure. Toxicity to organisms seems more dependent on acute exposure, while the chronic effects of low level exposure to heptachlor are poorly defined. Maximal terrestrial residues coincide with temporal and spatial proximity to application; peak residues in aquatic systems on the other hand, correlate to periods of maximum run-off. The lipophilic nature of both heptachlor and heptachlor epoxide results in the potential for significant bioaccumulation in all lipid-type compartments in the environment. The toxic effects of heptachlor are not specific for any one organ system. The liver and the central nervous system are most significantly affected by heptachlor, although effects can also be seen in the reproductive, hematopoietic, immune, and renal systems. An important consideration is the relation of relevant environmental exposure levels to toxicity. The concentrations necessary to elicit results in laboratory experiments do not translate directly to the same results upon environmental exposure, nor do experimental laboratory animal models absolutely equate with native-state organisms or with humans.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2403688

  8. Ecological effects and environmental fate of solid rocket exhaust

    NASA Technical Reports Server (NTRS)

    Nimmo, B.; Stout, I. J.; Mickus, J.; Vickers, D.; Madsen, B.

    1974-01-01

    Specific target processes were classified as to the chemical, chemical-physical, and biological reactions and toxic effects of solid rocket emissions within selected ecosystems at Kennedy Space Center. Exposure of Citris seedlings, English peas, and bush beans to SRM exhaust under laboratory conditions demonstrated reduced growth rates, but at very high concentrations. Field studies of natural plant populations in three diverse ecosystems failed to reveal any structural damage at the concentration levels tested. Background information on elemental composition of selected woody plants from two terrestrial ecosystems is reported. LD sub 50 for a native mouse (peromysous gossypinus) exposed to SRM exhaust was determined to be 50 ppm/g body weight. Results strongly indicate that other components of the SRM exhaust act synergically to enhance the toxic effects of HCl gas when inhaled. A brief summary is given regarding the work on SRM exhaust and its possible impact on hatchability of incubating bird eggs.

  9. Global ecology

    SciTech Connect

    Southwick, C.H.

    1985-01-01

    A general description of the earth as a biosphere is presented. Divergent views of near-future world scenarios are presented; the Global 2000 report, and the analysis of Simon and Kahn. The basic principles and trends in global ecology are outlined, and the basic pollution and environmental degradation problems are discussed. Humanistic considerations which affect global ecology (population control, the effects of largescale nuclear war, and third-world socio-economics) are discussed.

  10. The special effects of hypnosis and hypnotherapy: A contribution to an ecological model of therapeutic change.

    PubMed

    Mende, Matthias

    2006-04-01

    There is ample evidence that hypnosis enhances the effectiveness of psychotherapy and produces some astounding effects of its own. In this paper, the effective components and principles of hypnosis and hypnotherapy are analyzed. The "special" hypnotic and hypnotherapeutic effects are linked to the fact that the ecological requirements of therapeutic change are taken into account implicitly and/or explicitly when working with hypnotic trances in a therapeutic setting. The hypnotic situation is described--theoretically and in case examples--as a therapeutic modality that gratifies and aligns the basic emotional needs to feel autonomous, related, competent, and oriented. It is shown how the hypnotic relationship can help promote a sound ecological balance between these needs--a balance that is deemed to be a necessary prerequisite for salutogenesis. Practical implications for planning hypnotherapeutic interventions are discussed. PMID:16581689

  11. Effects of season on ecological processes in extensive earthen tilapia ponds in Southeastern Brazil.

    PubMed

    Favaro, E G P; Sipaúba-Tavares, L H; Milstein, A

    2015-11-01

    In Southeastern Brazil tilapia culture is conducted in extensive and semi-intensive flow-through earthen ponds, being water availability and flow management different in the rainy and dry seasons. In this region lettuce wastes are a potential cheap input for tilapia culture. This study examined the ecological processes developing during the rainy and dry seasons in three extensive flow-through earthen tilapia ponds fertilized with lettuce wastes. Water quality, plankton and sediment parameters were sampled monthly during a year. Factor analysis was used to identify the ecological processes occurring within the ponds and to construct a conceptual graphic model of the pond ecosystem functioning during the rainy and dry seasons. Processes related to nitrogen cycling presented differences between both seasons while processes related to phosphorus cycling did not. Ecological differences among ponds were due to effects of wind protection by surrounding vegetation, organic loading entering, tilapia density and its grazing pressure on zooplankton. Differences in tilapia growth among ponds were related to stocking density and ecological process affecting tilapia food availability and intraspecific competition. Lettuce wastes addition into the ponds did not produce negative effects, thus this practice may be considered a disposal option and a low-cost input source for tilapia, at least at the amounts applied in this study. PMID:26602348

  12. Evaluation of model predictions of the ecological effects of 4-nonylphenol -- before and after model refinement

    SciTech Connect

    Hanratty, M.P.; Liber, K.

    1994-12-31

    The Littoral Ecosystem Risk Assessment Model (LERAM) is a bioenergetic ecosystem effects model. It links single species toxicity data to a bioenergetic model of the trophic structure of an ecosystem in order to simulate community and ecosystem level effects of chemical stressors. LERAM was used in 1992 to simulate the ecological effects of diflubenzuron. When compared to the results from a littoral enclosure study, the model exaggerated the cascading of effects through the trophic levels of the littoral ecosystem. It was hypothesized that this could be corrected by making minor changes in the representation of the littoral food web. Two refinements of the model were therefore performed: (1) the plankton and macroinvertebrate model populations [eg., predatory Copepoda, herbivorous Insecta, green phytoplankton, etc.] were changed to better represent the habitat and feeding preferences of the endemic taxa; and (2) the method for modeling the microbial degradation of detritus (and the resulting nutrient remineralization) was changed from simulating bacterial populations to simulating bacterial function. Model predictions of the ecological effects of 4-nonylphenol were made before and after these refinements. Both sets of predictions were then compared to the results from a littoral enclosure study of the ecological effects of 4-nonylphenol. The changes in the LERAM predictions were then used to determine the success of the refinements, to guide. future research, and to further define LERAM`s domain of application.

  13. 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.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

    Kck, 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.

  16. Chemical mixtures and environmental effects: a pilot study to assess ecological exposure and effects in streams

    USGS Publications Warehouse

    Buxton, Herbert T.; Reilly, Timothy J.; Kuivila, Kathryn M.; Kolpin, Dana W.; Bradley, Paul M.; Villeneuve, Daniel L.; Mills, Marc A.

    2015-01-01

    Assessment and management of the risks of exposure to complex chemical mixtures in streams are priorities for human and environmental health organizations around the world. The current lack of information on the composition and variability of environmental mixtures and a limited understanding of their combined effects are fundamental obstacles to timely identification and prevention of adverse human and ecological effects of exposure. This report describes the design of a field-based study of the composition and biological activity of chemical mixtures in U.S. stream waters affected by a wide range of human activities and contaminant sources. The study is a collaborative effort by the U.S. Geological Survey and the U.S. Environmental Protection Agency. Scientists sampled 38 streams spanning 24 States and Puerto Rico. Thirty-four of the sites were located in watersheds impacted by multiple contaminant sources, including industrial and municipal wastewater discharges, crop and animal agricultural runoff, urban runoff, and other point and nonpoint contaminant sources. The remaining four sites were minimally development reference watersheds. All samples underwent comprehensive chemical and biological characterization, including sensitive and specific direct analysis for over 700 dissolved organic and inorganic chemicals and field parameters, identification of unknown contaminants (environmental diagnostics), and a variety of bioassays to evaluate biological activity and toxicity.

  17. Effects of algae growth on cadmium remobilization and ecological risk in sediments of Taihu Lake.

    PubMed

    Ni, Lixiao; Li, Dandan; Su, Lili; Xu, Jiajun; Li, Shiyin; Ye, Xiang; Geng, Hong; Wang, Peifang; Li, Yi; Li, Yiping; Acharya, Kumud

    2016-05-01

    Indoor simulation experiment with 2.76 L microcosms using sediment from Taihu Lake were conducted to investigate the relationship between algae bloom and heavy metals release into a lake aquatic environment. The results showed that Microcystic aeruginosa (M. aeruginosa) growth can enhance cadmium (Cd) mobilization from sediments to overlying water due to increasing pH and DO content of overlying water and changing the redox condition of surface sediment (0-2 cm) from weak oxidation to weak reduction. The dissolved Cd concentration in overlying water can be decreased during algal growth process. The remobilization of Cd from sediment can effectively reduce the ecological risk of total Cd in sediments. The results of this study showed that both Igeo and Er(i) can be used to effectively evaluate the ecological risk of heavy metal Cd in different fractions. PMID:26923240

  18. 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

  19. The Accumulation of Deleterious Mutations as a Consequence of Domestication and Improvement in Sunflowers and Other Compositae Crops.

    PubMed

    Renaut, Sebastien; Rieseberg, Loren H

    2015-09-01

    For populations to maintain optimal fitness, harmful mutations must be efficiently purged from the genome. Yet, under circumstances that diminish the effectiveness of natural selection, such as the process of plant and animal domestication, deleterious mutations are predicted to accumulate. Here, we compared the load of deleterious mutations in 21 accessions from natural populations and 19 domesticated accessions of the common sunflower using whole-transcriptome single nucleotide polymorphism data. Although we find that genetic diversity has been greatly reduced during domestication, the remaining mutations were disproportionally biased toward nonsynonymous substitutions. Bioinformatically predicted deleterious mutations affecting protein function were especially strongly over-represented. We also identify similar patterns in two other domesticated species of the sunflower family (globe artichoke and cardoon), indicating that this phenomenon is not due to idiosyncrasies of sunflower domestication or the sunflower genome. Finally, we provide unequivocal evidence that deleterious mutations accumulate in low recombining regions of the genome, due to the reduced efficacy of purifying selection. These results represent a conundrum for crop improvement efforts. Although the elimination of harmful mutations should be a long-term goal of plant and animal breeding programs, it will be difficult to weed them out because of limited recombination. PMID:25939650

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. Ecological effects of perorally administered pivmecillinam on the normal vaginal microflora.

    PubMed

    Sullivan, Asa; Fianu-Jonasson, Aino; Landgren, Britt-Marie; Nord, Carl Erik

    2005-01-01

    The knowledge of the effects of antimicrobial agents on the normal vaginal microflora is limited. The objective of the present study was to study the ecological impact of pivmecillinam on the normal vaginal microflora. In 20 healthy women, the estimated day of ovulation was determined during three subsequent menstrual cycles. Microbiological and clinical examinations were performed on the estimated day of ovulation and on day 3 in all cycles and also on day 7 after ovulation in cycles 1 and 2. Anaerobic and facultative anaerobic gram-positive rods, mainly species of lactobacilli and actinomycetes, dominated the microflora. One woman was colonized on the third day of administration with a resistant Escherichia coli strain, and Candida albicans was detected in one woman on days 3 and 7 in cycle 2. No other major changes in the normal microflora occurred during the study. Administration of pivmecillinam had a minor ecological impact on the normal vaginal microflora. PMID:15616292

  5. Fate, effect, and ecological risk of mercury from historic releases in the Danvers Estuary (Massachusetts)

    SciTech Connect

    Mauahan, J.; Raddatz, A.

    1995-12-31

    High concentrations (up to 400 mg/kg) of mercury were initially detected in intertidal sediments adjacent to a manufacturing area. Based on the potential for ecological risk from exposure to the sediments, a detailed investigation was initiated to determine the distribution, fate and ecological effects of the mercury. The program consisted of collecting undisturbed sediment cores from an area radiating out from the high concentration area approximately 300 meters. The cores were analyzed for total mercury, grain size, total organic carbon, and methylmercury. Blue mussels (Mytilus edulis) were also collected and analyzed for total mercury. Sediments and mussels were also collected from areas of the estuary approximately 1 km away and unaffected by historic mercury releases to serve as an estimate of background concentrations. Concentrations of total mercury, methylmercury and mercury in M. edulis tissue showed very similar distribution patterns and a strong statistical correlation (r{sup 2} of approximately 0.8). The elevated concentrations (10 to 20 mg/kg) were confined to an area with a radius less than 30 meters and dropped off very abruptly. Beyond 30 meters, concentrations were equal to or less than concentrations considered to represent background both from reference samples and sampling reported in the literature. The results were compared to ecological effects levels or benchmarks developed for the investigation. Levels outside the 30 meter radius were determined to pose no imminent hazard or risk or harm (as defined by the Massachusetts Contingency Plan and the benchmarks developed for the project). There was no imminent hazard from the sediments within the 30 meter radius but the comparison to benchmarks within the area indicated risk of ecological harm.

  6. 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...

  7. Ecological effects assessment of industrial sludge for microarthropods and decomposition in a spruce plantation.

    PubMed

    Krogh, P H; Pedersen, M B

    1997-03-01

    Effects of dried, granulated industrial sludge-containing residues of organic pesticides and precursors were assessed for microarthropod fauna and the decomposition of a spruce forest floor. The investigation was highly realistic, using large plots of about 1/2 ha, and the application was done with professional equipment. The ecological effects of the sludge were compared with the ecological effects of an inorganic fertilizer. Decreases in abundance of the microarthropods ranged from 20 to 80% of the control level after 1 year. Isotoma notabilis Schffer was the only species that exhibited stimulation at twice the control level due to the sludge. The least affected collembolan species was Lepidocyrtus cyaneus Tullberg, a member of the surface-dwelling life forms. Sensitive species were Isotoma anglicana Lubbock and Isotomiella minor Schffer. In subhabitats with almost no application of sludge due to a heterogeneous horizontal distribution, the microarthropods were still affected to the same degree as those in the zones of maximum application. Laboratory tests with Folsomia candida Willem gave results similar to the effects on field populations concerning the sludge but revealed no adverse effects of the fertilizer. Decomposition was stimulated to the same extent in the field by the two types of fertilizer but in the laboratory the sludge caused the largest stimulation. The effects on the microarthropod fauna are suggested to be the result of a combination of direct toxicity and changes in the microbial community due to fertilizers. PMID:9126433

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

    PubMed Central

    Gheorghiţă, Valeriu; Barbu, Alina Elena; Gheorghiu, Monica Livia; Căruntu, 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

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

    PubMed

    Gheorghiţă, Valeriu; Barbu, Alina Elena; Gheorghiu, Monica Livia; Căruntu, 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

  10. Purging deleterious mutations in conservation programmes: combining optimal contributions with inbred matings

    PubMed Central

    de Cara, M Á R; Villanueva, B; Toro, M Á; Fernández, J

    2013-01-01

    Conservation programmes aim at minimising the loss of genetic diversity, which allows populations to adapt to potential environmental changes. This can be achieved by calculating how many offspring every individual should contribute to the next generation to minimise global coancestry. However, an undesired consequence of this strategy is that it maintains deleterious mutations, compromising the viability of the population. In order to avoid this, optimal contributions could be combined with inbred matings, to expose and eliminate recessive deleterious mutations by natural selection in a process known as purging. Although some populations that have undergone purging experienced reduced inbreeding depression, this effect is not consistent across species. Whether purging by inbred matings is efficient in conservation programmes depends on the balance between the loss of diversity, the initial decrease in fitness and the reduction in mutational load. Here we perform computer simulations to determine whether managing a population by combining optimal contributions with inbred matings improves its long-term viability while keeping reasonable levels of diversity. We compare the management based on genealogical information with management based on molecular data to calculate coancestries. In the scenarios analysed, inbred matings never led to higher fitness and usually maintained lower diversity than random or minimum coancestry matings. Replacing genealogical with molecular coancestry can maintain a larger genetic diversity but can also lead to a lower fitness. Our results are strongly dependent on the mutational model assumed for the trait under selection, the population size during management and the reproductive rate. PMID:23321706

  11. Predicting the impact of deleterious single point mutations in SMAD gene family using structural bioinformatics approach.

    PubMed

    George Priya Doss, C; Nagasundaram, N; Tanwar, Himani

    2012-06-01

    Functional alteration in SMAD proteins leads to dis-regulation of its mechanism results in possibilities of high risk diseases like fibrosis, cancer, juvenile polyposis etc. Studying single nucleotide polymorphism (SNP) in SMAD genes helps understand the malfunction of these proteins. In this study, we focused on deleterious effects of nsSNPs in both structural and functional level using publically available bioinformatics tools. We have mainly focused on identifying deleterious nsSNPs in both structural and functional level in SMAD genes by using SIFT, PolyPhen, SNPs&GO, I-Mutant 3.0, MUpro and PANTHER. Structure analysis was carried out with the major mutation that occurred in the native protein coded by SMAD genes and its amino acid positions (R358W, K306S, R310G, S433R and R361C). SRide was used to check the stability of the native and mutant modelled proteins. In addition, we used MAPPER to identify SNPs present in transcription factor binding sites. These findings demonstrate that the in silico approaches can be used efficiently to identify potential candidate SNPs in large scale analysis. PMID:22843233

  12. 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

  13. Environmental monitoring and ecological risk assessment for pesticide contamination and effects in Lake Pamvotis, northwestern Greece.

    PubMed

    Hela, Dimitra G; Lambropoulou, Dimitra A; Konstantinou, Ioannis K; Albanis, Triantafyllos A

    2005-06-01

    Monitoring of pesticide residues in water and sediments was conducted as a basis for subsequent ecotoxicological risk assessment for the shallow eutrophic Lake Pamvotis, northwestern Greece. During a one-year study period, atrazine, desethylatrazine (DEA), simazine, diazinon, malathion, oxamyl, carbofuran, and ethion were detected in water and atrazine, desethylatrazine, diazinon, and s-ethyl dipropylthiocarbamate (EPTC) in sediments, all at ppb concentration level. Temporal variation in pesticide concentrations was observed. Highest residue levels for most pesticides in both water and sediment matrices occurred in the May to July period with the exception of atrazine and DEA, which show highest levels in water during the September to November period. The ecological risk associated with pesticide contamination was assessed using two different methods: The toxic unit method, which provides a first indication of the relative contribution of detected pesticides to the total toxicity and a probabilistic approach, and the inverse method of Van Straalen and Denneman, which is used to quantify the ecological risk. The maximum percentage of the ecological risk was 10.3 and 51.8% for water and 17.2 and 70.6% for sediment, based on acute and chronic level, respectively. These results show that pesticides exert a significant pressure on the aquatic system of Lake Pamvotis, especially for the chronic-effect level. Simple quotient methods should be coupled with higher-tier risk assessment, especially if restoration activities on lake ecosystems are to be undertaken for sustainable development. PMID:16117136

  14. Population demographic models in ecological risk assessment: Interpreting effects and predicting contaminant risk

    SciTech Connect

    Dillon, T.M.

    1994-12-31

    Ecological risk can be assessed at different levels of biological organization: biochemical, whole animal, populations and communities. Each level is characterized by varying degrees of contaminant sensitivity, response time, causal linkage and ecological interpretation. Whole animal bioassays are used in research and regulatory programs to assess contaminant impacts. In many ways, bioassays represent a compromise between the need for rapid, sensitive testing and the desire to measure ecologically important endpoints. Population demographic models represent a tool for interpreting bioassay results. They integrate life-history information and project population-level contaminant effects. Four important research issues must be addressed before demographic models can be fully utilized in this manner. Assumptions and extrapolations accompanying many models must be critically examined; e.g. assumption of no density-dependence and spatial/temporal extrapolations. Laboratory-based models must be calibrated with field-derived demographic models. Population models must be coupled with exposure models to characterize contaminant risk. Finally, field verification studies must be conducted to evaluate the accuracy of demographic model predictions.

  15. Life history plasticity magnifies the ecological effects of a social wasp invasion

    PubMed Central

    Wilson, Erin E.; Mullen, Lynne M.; Holway, David A.

    2009-01-01

    An unresolved question in ecology concerns why the ecological effects of invasions vary in magnitude. Many introduced species fail to interact strongly with the recipient biota, whereas others profoundly disrupt the ecosystems they invade through predation, competition, and other mechanisms. In the context of ecological impacts, research on biological invasions seldom considers phenotypic or microevolutionary changes that occur following introduction. Here, we show how plasticity in key life history traits (colony size and longevity), together with omnivory, magnifies the predatory impacts of an invasive social wasp (Vespula pensylvanica) on a largely endemic arthropod fauna in Hawaii. Using a combination of molecular, experimental, and behavioral approaches, we demonstrate (i) that yellowjackets consume an astonishing diversity of arthropod resources and depress prey populations in invaded Hawaiian ecosystems and (ii) that their impact as predators in this region increases when they shift from small annual colonies to large perennial colonies. Such trait plasticity may influence invasion success and the degree of disruption that invaded ecosystems experience. Moreover, postintroduction phenotypic changes may help invaders to compensate for reductions in adaptive potential resulting from founder events and small population sizes. The dynamic nature of biological invasions necessitates a more quantitative understanding of how postintroduction changes in invader traits affect invasion processes. PMID:19625616

  16. Detecting the ecological effects of environmental impacts: A case study of kelp forest invertebrates

    SciTech Connect

    Schroeter, S.C.; Dixon, J.D. Univ. of Southern California, Los Angeles, CA ); Kastendiek, J. Univ. of Southern California, Los Angeles, CA ); Smith, R.O. Univ. of Southern California, Los Angeles, CA ); Bence, J.R. )

    1993-05-01

    Detecting the environmental impacts of human activities on natural communities is a central problem in applied ecology. One must separate human perturbations, usually unique events, from considerable natural temporal variability in most populations. These problems can be successfully addressed with the Before-After/Control-Impact (BACI) sampling design, in which Impact and Control sites are sampled contemporaneously and repeatedly in periods Before and After the human perturbation. In this case, the ecological effects of the cooling water discharge from a coastal nuclear power plant in southern California was examined. The results suggest some general lessons applicable in many ecological contexts. In systems where plants and animals are long-lived and recruit sporadically, the rates of change in density are often so low that sampling more than a few times per year will introduce serial correlations in the data. As a result, for studies of few years duration, few samples will be taken. A small sample size means that the tests of the underlying assumptions underlying, e.g., independence and additivity, will have low power. This injects uncertainty into the conclusions. Small sample size also means detecting any but very large effects will be low. In our study, sampling periods of 2-3 yr both Before and After the impact were not long enough to detect a halving or doubling of populations. We concluded that there were significant environmental impacts because: (1) the effect size was generally very large ([approx] -75%); (2) there was a consistent pattern among species; (3) there were two Impact sites, and effects were larger at the site nearest the discharge; (4) the observed effects accorded with physical changes that could be linked with the source of impact; and (5) a number of alternative mechanisms, unrelated to the source of impact, were examined and rejected. 37 figs., 6 figs., 10 tabs.

  17. Environmental Stress, Bottom-up Effects, and Community Dynamics: Integrating Molecular-Physiological and Ecological Approaches.

    PubMed

    Menge, Bruce A; Olson, Annette M; Dahlhoff, Elizabeth P

    2002-08-01

    Environmental stress and nutrient/productivity models predict the responses of community structure along gradients of physical conditions and bottom-up effects. Although both models have succeeded in helping to understand variation in ecological communities, most tests have been qualitative. Until recently, two roadblocks to more quantitative tests in marine environments have been a lack of (1) inexpensive, field-deployable technology for quantifying (e.g.) temperature, light, salinity, chlorophyll, and productivity, and (2) methods of quantifying the sub-organismal mechanisms linking environmental conditions to their ecological expression. The advent of inexpensive remote-sensing technology, adoption of molecular techniques such as quantification of heat-shock proteins and RNA:DNA ratios, and the formation of interdisciplinary alliances between ecologists and physiologists has begun to overcome these roadblocks. An integrated eco-physiological approach focuses on the determinants of: distributional limits among microhabitat patches and along (local-scale) environmental gradients (e.g., zonation); among-site (mesoscale) differences in community pattern; and geographic (macroscale) differences in ecosystem structure. These approaches promise new insights into the physiological mechanisms underlying variation in processes such as species interactions, physical disturbance, survival and growth. Here, we review two classes of models for community dynamics, and present examples of ecological studies of these models in consumer-prey systems. We illustrate the power of new molecular tools to characterize the sub-organismal responses of some of the same consumers and prey to thermal stress and food concentration. Ecological and physiological evidence tends to be consistent with model predictions, supporting our argument that we are poised to make major advances in the mechanistic understanding of community dynamics along key environmental gradients. PMID:21708788

  18. Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

    PubMed

    Turley, Nash E; Johnson, Marc T J

    2015-07-01

    Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6 larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology. PMID:25740334

  19. Winter Ecology.

    ERIC Educational Resources Information Center

    Birkeland, Karl W.; Halfpenny, James C.

    1987-01-01

    Discusses some of the ecological variables involved with plant and animal survival during the winter months. Addresses the effects of changing climatic conditions on habitats, foot-loading indexes, and the overall concept of adaptation. Provides some simple teaching activities dealing with winter survival. (TW)

  20. Cadmium in aquatic microcosms: Implications for screening the ecological effects of toxic substances

    NASA Astrophysics Data System (ADS)

    Hendrix, Paul F.; Langner, Christine L.; Odum, Eugene P.

    1982-11-01

    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 4×4 factorial experiment dealing with the interactive effects of cadmium and nutrients in static microcosms. Phase II was a 2×4 factorial experiment using flowthrough microcosms to study temporal aspects of system behavior in response to nutrient loading and chronic versus acute cadmium perturbations. Nutrient enrichment resulted in increased biomass and metabolic activity in both static and flowthrough microcosms. Cadmium treatments generally resulted in a decrease in abundance of grazing crustaceans and a subsequent increase in community respiration, suggesting a change in community structure from a grazing to a detritus food chain. Of the variables measured, community metabolism, community composition, and output/input ratios of nitrate-nitrogen were the most useful indicators of system response to cadmium. Nutrient enrichment significantly influenced cadmium effects with respect to most of the variables measured; high levels of enrichment reduced the effects of cadmium. For screening the ecological effects of toxic chemicals, a series of experiments is proposed, including 1) relatively simple static microcosms, 2) flow through microcosms, and 3) more detailed but selective studies in microcosms derived from specific ecosystems. Each step yields increasingly more information and serves as a guide for subsequent experiments; in addition, each step more closely approximates natural ecosystems.

  1. Diversity, decoys and the dilution effect: how ecological communities affect disease risk.

    PubMed

    Johnson, P T J; Thieltges, D W

    2010-03-15

    Growing interest in ecology has recently focused on the hypothesis that community diversity can mediate infection levels and disease ('dilution effect'). In turn, biodiversity loss--a widespread consequence of environmental change--can indirectly promote increases in disease, including those of medical and veterinary importance. While this work has focused primarily on correlational studies involving vector-borne microparasite diseases (e.g. Lyme disease, West Nile virus), we argue that parasites with complex life cycles (e.g. helminths, protists, myxosporeans and many fungi) offer an excellent additional model in which to experimentally address mechanistic questions underlying the dilution effect. Here, we unite recent ecological research on the dilution effect in microparasites with decades of parasitological research on the decoy effect in macroparasites to explore key questions surrounding the relationship between community structure and disease. We find consistent evidence that community diversity significantly alters parasite transmission and pathology under laboratory as well as natural conditions. Empirical examples and simple transmission models highlight the diversity of mechanisms through which such changes occur, typically involving predators, parasite decoys, low competency hosts or other parasites. However, the degree of transmission reduction varies among diluting species, parasite stage, and across spatial scales, challenging efforts to make quantitative, taxon-specific predictions about disease. Taken together, this synthesis highlights the broad link between community structure and disease while underscoring the importance of mitigating ongoing changes in biological communities owing to species introductions and extirpations. PMID:20190121

  2. Deleterious c-Cbl Exon Skipping Contributes to Human Glioma.

    PubMed

    Seong, Min Woo; Ka, Seung Hyeun; Park, Ji Ho; Park, Jong Ho; Yoo, Hee Min; Yang, Seung Wook; Park, Jung Mi; Park, Dongeun; Lee, Soon Tae; Seol, Jae Hong; Chung, Chin Ha

    2015-06-01

    c-Cbl, a RING-type ubiquitin E3 ligase, downregulates various receptor tyrosine kinases (e.g., epidermal growth factor receptor (EGFR)), leading to inhibition of cell proliferation. Moreover, patients with myeloid neoplasm frequently harbor c-Cbl mutations, implicating the role of c-Cbl as a tumor suppressor. Recently, we have shown that c-Cbl downregulates ?Pix-mediated cell migration and invasion, and the lack of c-Cbl in the rat C6 and human A172 glioma cells is responsible for their malignant behavior. Here, we showed that c-Cbl exon skipping occurs in the glioma cells and the brain tissues from glioblastoma patients lacking c-Cbl. This exon skipping resulted in generation of two types of c-Cbl isoforms: type I lacking exon-9 and type II lacking exon-9 and exon-10. However, the c-Cbl isoforms in the cells and tissues could not be detected as they were rapidly degraded by proteasome. Consequently, C6 and A172 cells showed sustained EGFR activation. However, no splice site mutation was found in the region from exon-7 to exon-11 of the c-Cbl gene in C6 cells and a glioblastoma tissue lacking c-Cbl. In addition, c-Cbl exon skipping could be induced when cells transfected with a c-Cbl mini-gene were grown to high density or under hypoxic stress. These results suggest that unknown alternations (e.g., mutation) of splicing machinery in C6 and A172 cells and the glioblastoma brain tissues are responsible for the deleterious exon skipping. Collectively, these findings indicate that the c-Cbl exon skipping contributes to human glioma and its malignant behavior. PMID:26152360

  3. Mechanistic effect modeling for ecological risk assessment: where to go from here?

    PubMed

    Grimm, Volker; Martin, Benjamin T

    2013-07-01

    Mechanistic effect models (MEMs) consider the mechanisms of how chemicals affect individuals and ecological systems such as populations and communities. There is an increasing awareness that MEMs have high potential to make risk assessment of chemicals more ecologically relevant than current standard practice. Here we discuss what kinds of MEMs are needed to improve scientific and regulatory aspects of risk assessment. To make valid predictions for a wide range of environmental conditions, MEMs need to include a sufficient amount of emergence, for example, population dynamics emerging from what individual organisms do. We present 1 example where the life cycle of individuals is described using Dynamic Energy Budget theory. The resulting individual-based population model is thus parameterized at the individual level but correctly predicts multiple patterns at the population level. This is the case for both control and treated populations. We conclude that the state-of-the-art in mechanistic effect modeling has reached a level where MEMs are robust and predictive enough to be used in regulatory risk assessment. Mechanistic effect models will thus be used to advance the scientific basis of current standard practice and will, if their development follows Good Modeling Practice, be included in a standardized way in future regulatory risk assessments. PMID:23564619

  4. Restoring fish ecological quality in estuaries: Implication of interactive and cumulative effects among anthropogenic stressors.

    PubMed

    Teichert, Nils; Borja, Angel; Chust, Guillem; Uriarte, Ainhize; Lepage, Mario

    2016-01-15

    Estuaries are subjected to multiple anthropogenic stressors, which have additive, antagonistic or synergistic effects. Current challenges include the use of large databases of biological monitoring surveys (e.g. the European Water Framework Directive) to help environmental managers prioritizing restoration measures. This study investigated the impact of nine stressor categories on the fish ecological status derived from 90 estuaries of the North East Atlantic countries. We used a random forest model to: 1) detect the dominant stressors and their non-linear effects; 2) evaluate the ecological benefits expected from reducing pressure from stressors; and 3) investigate the interactions among stressors. Results showed that largest restoration benefits were expected when mitigating water pollution and oxygen depletion. Non-additive effects represented half of pairwise interactions among stressors, and antagonisms were the most common. Dredged sediments, flow changes and oxygen depletion were predominantly implicated in non-additive interactions, whereas the remainder stressors often showed additive impacts. The prevalence of interactive impacts reflects a complex scenario for estuaries management; hence, we proposed a step-by-step restoration scheme focusing on the mitigation of stressors providing the maximum of restoration benefits under a multi-stress context. PMID:26520263

  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. 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 atm) 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

  7. A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems.

    PubMed

    Rosi-Marshall, E J; Snow, D; Bartelt-Hunt, S L; Paspalof, A; Tank, J L

    2015-01-23

    Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment. PMID:25062553

  8. Association between loci with deleterious alleles and distorted sex ratios in an inbred line of tilapia (Oreochromis aureus).

    PubMed

    Shirak, A; Palti, Y; Cnaani, A; Korol, A; Hulata, G; Ron, M; Avtalion, R R

    2002-01-01

    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 were mapped previously to different linkage groups and were shown to be associated with genes with deleterious alleles in this line. A restricted maximum likelihood model was used for analysis of major effects and their interactions on sex ratio and viability. This model was based on selective mortality of genders, ignoring effects of possible sex-determining genes. The results showed that deleterious genes linked to UNH216 and UNH231 exert higher lethality in females than in males (P < .0005 and P < .05, respectively). UNH159 was not associated directly with sex ratio distortion, but acts strongly as a modifier of sex ratio in combination with UNH216 and UNH231. Each of the three loci was found to have a significant effect on viability (P < .05) in the maximum likelihood analysis. The deleterious single-locus effects act strongly against females, while most of the epistatic interactions exert higher lethality in males. This contradiction results in a close to 1:1 sex ratio at maturity. The genetic mechanism and significance of such a balance between genders are still unknown. A detailed analysis of sex-specific lethality may be applied by screening in appropriate series of matings and fine mapping with additional markers. Our data suggest that UNH216 and UNH231 are linked to sex ratio distortion genes and that UNH159 may be linked to a modifier of these genes. PMID:12407213

  9. Carnivore repatriation and holarctic prey: narrowing the deficit in ecological effectiveness.

    PubMed

    Berger, Joel

    2007-08-01

    The continuing global decline of large carnivores has catalyzed great interest in reintroduction to restore populations and to reestablish ecologically functional relationships. I used variation in the distribution of four Holarctic prey species and their behavior as proxies to investigate the pace and intensity by which responses are lost or reinvigorated by carnivore repatriation. By simulating the presence of wolves (Canis lupus), tigers (Panthera tigris), and brown bears (Ursus arctos) at 19 transcontinental sites, I assayed three metrics of prey performance in areas with no large terrestrial carnivores (the polar islands of Greenland and Svalbard), extant native carnivores (Eastern Siberian Shield, boreal Canada, and Alaska); and repatriated carnivores (the Yellowstone region and Rocky Mountains). The loss and reestablishment of large carnivores changed the ecological effectiveness of systems by (1) dampening immediate group benefits, diminishing awareness, and diminishing flight reaction in caribou (Rangifer tarandus) where predation was eliminated and (2) reinstituting sensitivity to carnivores by elk (Cervus elaphus) and moose (Alces alces) in the Yellowstone region to levels observed in Asian elk when sympatric with Siberian tigers and wolves or in Alaskan moose sympatric with wolves. Behavioral compensation to reintroduced carnivores occurred within a single generation, but only the vigilance reaction of bison (Bison bison) in Yellowstone exceeded that of their wolf-exposed conspecifics from boreal Canada. Beyond these overt responses by prey, snow depth and distance to suitably vegetated habitat was related to heightened vigilance in moose and elk, respectively, but only at sites with carnivores. These findings are insufficient to determine whether similar patterns might apply to other species or in areas with alien predators, and they suggest that the presumed excessive vulnerability of nave prey to repatriated carnivores may be ill-founded. Although behavior offers a proxy to evaluate ecological effectiveness, a continuing challenge will be to understand how nave prey respond to novel or introduced predators. PMID:17650259

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. [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

  17. Effect of antimicrobial agents on the ecological balance of human microflora.

    PubMed

    Sullivan, A; Edlund, C; Nord, C E

    2001-09-01

    The normal microflora acts as a barrier against colonisation of potentially pathogenic microorganisms and against overgrowth of already present opportunistic microorganisms. Control of growth of opportunistic microorganisms is termed colonisation resistance. Administration of antimicrobial agents, therapeutically or as prophylaxis, causes disturbances in the ecological balance between the host and the normal microflora. Most studies on the impact of antimicrobial agents on normal microflora have been carried out on the intestinal flora. Less is known on the effects on oropharyngeal, skin, and vaginal microflora. Disturbances in the microflora depend on the properties of the agents as well as of the absorption, route of elimination, and possible enzymatic inactivation and/or binding to faecal material of the agents. The clinically most common disturbances in the intestinal microflora are diarrhoea and fungal infections that usually cease after the end of treatment. A well-balanced microflora prevents establishment of resistant microbial strains. By using antimicrobial agents that do not disturb colonisation resistance, the risk of emergence and spread of resistant strains between patients and dissemination of resistant determinants between microorganisms is reduced. In this article, the potential ecological effects of administration of antimicrobial agents on the intestinal, oropharyngeal, and vaginal microflora are summarised. The review is based on clinical studies published during the past 10 years. PMID:11871461

  18. Non-Dioxin-Like PCBs: Effects and Consideration in Ecological Risk Assessments

    EPA Science Inventory

    This response document was written in response to a request received by ORD’s Ecological Risk Assessment Support Center (ERASC) from the Ecological Risk Assessment Forum (ERAF). The purpose of this report is to o provide ecological risk assessors with a concise summary of the sta...

  19. Non-Dioxin-Like PCBs: Effects and Consideration in Ecological Risk Assessments

    EPA Science Inventory

    This response document was written in response to a request received by ORDs Ecological Risk Assessment Support Center (ERASC) from the Ecological Risk Assessment Forum (ERAF). The purpose of this report is to o provide ecological risk assessors with a concise summary of the sta...

  20. Do Deleterious Mutations Act Synergistically? Metabolic Control Theory Provides a Partial Answer

    PubMed Central

    Szathmary, E.

    1993-01-01

    Metabolic control theory is used to derive conditions under which two deleterious mutations affecting the dynamics of a metabolic pathway act synergistically. It is found that two mutations tend to act mostly synergistically when they reduce the activity of the same enzyme. If the two mutations affect different enzymes, the conclusion depends on the way that fitness is determined by aspects of the pathway. The cases analyzed are: selection for (1) maximal flux, (2) maximal equilibrium concentration (pool size) of an intermediate, (3) optimal flux, (4) optimal pool size. The respective types of epistasis found are: (1) antagonistic, (2) partly synergistic, (3-4) synergism is likely to predominate over antagonism. This results in somewhat different predictions concerning the effect of metabolic mutations on fitness in prokaryotes and eukaryotes. The fact that bacteria are largely clonal but have often a mosaic gene structure is consistent with expectations from the model. PMID:8417983

  1. Southeast Asian primate communities: the effects of ecology and Pleistocene refuges on species richness.

    PubMed

    Hassel-Finnegan, Heather; Borries, Carola; Zhao, Qing; Phiapalath, Phaivanh; Koenig, Andreas

    2013-12-01

    We examined historical and ecological factors affecting current primate biodiversity in Southeast Asia. In Africa, Madagascar and South America, but not Southeast Asia, primate species richness is positively associated with average rainfall and distance from the equator (latitude). We predicted that Southeast Asia's non-conformance may be due to the effect of dispersed Pleistocene refuges (locations of constricted tropical forests during glacial maxima which today are at least 305 m in altitude). Based on 45 forested sites (13 on large islands; 32 on the mainland) of at least 100 km(2) to minimize recent human impact, we determined correlations between extant primate species richness and rainfall, latitude and supplementary ecological variables, while controlling for refuges and islands. We found that refuge sites had significantly higher primate species richness than non-refuges (t = -2.76, P < 0.05), and distance from the nearest Pleistocene refuge was negatively correlated with species richness for non-refuge sites (r = -0.51, P < 0.05). There was no difference in species richness between sites on large islands and the mainland (t = -1.4, P = 0.16). The expected positive relationship between rainfall and species richness was not found (r = 0.17, P = 0.28). As predicted, primate species richness was negatively correlated with latitude (r = -0.39, P < 0.05) and positively correlated with mean temperature (r = 0.45, P < 0.05). General linear models indicated that a site's latitude (F1,38 = 6.18, P < 0.05) and Pleistocene refuge classification (F1,42 = 5.96, P < 0.05) were the best predictors of species richness. Both ecological and historical factors contribute to present day primate species richness in Southeast Asia, making its biodiversity less of an outlier than previously believed. PMID:24344966

  2. 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.

  3. 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

  4. 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…

  5. 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.

  6. 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.

  7. Environmental stress increases selection against and dominance of deleterious mutations in inbred families of the Pacific oyster Crassostrea gigas.

    PubMed

    Plough, Louis V

    2012-08-01

    The deleterious effects of inbreeding are well documented and of major concern in conservation biology. Stressful environments have generally been shown to increase inbreeding depression; however, little is known about the underlying genetic mechanisms of the inbreeding-by-stress interaction and to what extent the fitness of individual deleterious mutations is altered under stress. Using microsatellite marker segregation data and quantitative trait locus (QTL) mapping methods, I performed a genome scan for deleterious mutations affecting viability (viability or vQTL) in two inbred families of the Pacific oyster Crassostrea gigas, reared in a stressful, nutrient-poor diet and a favourable, nutrient-rich diet, which had significant effects on growth and survival. Twice as many vQTL were detected in the stressful diet compared with the favourable diet, resulting primarily from substantially greater mortality of homozygous genotypes. At vQTL, estimates of selection (s) and dominance (h) were greater in the stressful environment (= 0.86 vs. 0.54 and = 0.35 vs. 0.18, in stressful and nonstressful diets, respectively). There was no evidence of interaction between vQTL. Individual vQTL differed across diets in selection only, or in both selection and dominance, and some vQTL were not affected by diet. These results suggest that stress-associated increases in selection against individual deleterious alleles underlie greater inbreeding depression with stress. Furthermore, the finding that inbreeding-by-environment interaction appears, to some extent, to be locus specific, helps to explain previous observations of lineage-specific expression of inbreeding depression and environment-specific purging, which have important implications for conservation and evolutionary biology. PMID:22747636

  8. Mechanisms of nonlethal predator effect on cohort size variation: ecological and evolutionary implications.

    PubMed

    Peacor, Scott D; Schiesari, Luis; Werner, Earl E

    2007-06-01

    Understanding the factors responsible for generating size variation in cohorts of organisms is important for predicting their population and evolutionary dynamics. We group these factors into two broad classes: those due to scaling relationships between growth and size (size-dependent factors), and those due to individual trait differences other than size (size-independent factors; e.g., morphology, behavior, etc.). We develop a framework predicting that the nonlethal presence of predators can have a strong effect on size variation, the magnitude and sign of which depend on the relative influence of both factors. We present experimental results showing that size-independent factors can strongly contribute to size variation in anuran larvae, and that the presence of a larval dragonfly predator reduced expression of these size-independent factors. Further, a review of a number of experiments shows that the effect of this predator on relative size variation of a cohort ranged from negative at low growth rates to positive at high growth rates. At high growth rates, effects of size-dependent factors predominate, and predator presence causes an increase in the scaling of growth rate with size (larger individuals respond less strongly to predator presence than small individuals). Thus predator presence led to an increase in size variation. In contrast, at low growth rates, size-independent factors were relatively more important, and predator presence reduced expression of these size-independent factors. Consequently, predator presence led to a decrease in size variation. Our results therefore indicate a further mechanism whereby nonlethal predator effects can be manifest on prey species performance. These results have strong implications for both ecological and evolutionary processes. Theoretical studies indicate that changes in cohort size variation can have profound effects on population dynamics and stability, and therefore the mere presence of a predator could have important ecological consequences. Further, changes in cohort size variation can have important evolutionary implications through changes in trait heritability. PMID:17601145

  9. Resource type influences the effects of reserves and connectivity on ecological functions.

    PubMed

    Yabsley, Nicholas A; Olds, Andrew D; Connolly, Rod M; Martin, Tyson S H; Gilby, Ben L; Maxwell, Paul S; Huijbers, Chantal M; Schoeman, David S; Schlacher, Thomas A

    2016-03-01

    Connectivity is a pivotal feature of landscapes that affects the structure of populations and the functioning of ecosystems. It is also a key consideration in conservation planning. But the potential functional effects of landscape connectivity are rarely evaluated in a conservation context. The removal of algae by herbivorous fish is a key ecological function on coral reefs that promotes coral growth and recruitment. Many reef herbivores are harvested and some use other habitats (like mangroves) as nurseries or feeding areas. Thus, the effects of habitat connectivity and marine reserves can jointly promote herbivore populations on coral reefs, thereby influencing reef health. We used a coral reef seascape in eastern Australia to test whether seascape connectivity and reserves influence herbivory. We measured herbivore abundance and rates of herbivory (on turf algae and macroalgae) on reefs that differed in both their level of connectivity to adjacent mangrove habitats and their level of protection from fishing. Reserves enhanced the biomass of herbivorous fish on coral reefs in all seascape settings and promoted consumption of turf algae. Consumption of turf algae was correlated with the biomass of surgeonfish that are exploited outside reserves. By contrast, both reserve status and connectivity influenced herbivory on macroalgae. Consumption of macroalgae was greatest on fished reefs that were far from mangroves and was not strongly correlated with any fish species. Our findings demonstrate that landscape connectivity and reserve status can jointly affect the functioning of ecosystems. Moreover, we show that reserve and connectivity effects can differ markedly depending on resource type (in this case turf algae vs. macroalgae). The effectiveness of conservation initiatives will therefore depend on our ability to understand how these multiple interactive effects structure the distribution of ecological functions. These findings have wider implications for the spatial conservation of heterogeneous environments and strengthen the case that the impact of conservation on ecosystem functioning is contingent on how reserves are positioned in landscapes. PMID:26476209

  10. Ecological effects of pharmaceuticals in aquatic systems—impacts through behavioural alterations

    PubMed Central

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

    2014-01-01

    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

  11. 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.

  12. Face Adaptation Effects Show Strong and Long-Lasting Transfer from Lab to More Ecological Contexts

    PubMed Central

    Carbon, Claus-Christian; Ditye, Thomas

    2012-01-01

    A review on recent experiments on figural face aftereffects reveals that adaptation effects in famous faces can last for hours up to days. Such adaptations seem to be highly reliable regarding testretest designs as well as regarding the generalizability of adaptation across different adaptation routines and adaptations toward different kinds of facial properties. However, in the studies conducted so far, adaptation and the subsequent test phase were carried out in typical laboratory environments. Under these circumstances, it cannot be ruled out that the observed effects are, in fact, episodic learntest compatibility effects. To test for ecological validity in adaptation effects we used an adaptation paradigm including environmental and social properties that differed between adaptation and test phase. With matched samples (n1?=?n2?=?54) we found no main effects of experimental setting compatibility resulting from varying where the tests where conducted (environmental condition) nor any interaction with effects of stimulus compatibility resulting from varying stimulus similarity between adaptation and test phase using the same picture, different pictures of the same person, or different persons (transfer). This indicates that these adaptation effects are not artificial or merely lab-biased effects. Adaptation to face stimuli may document representational adaptations and tuning mechanisms that integrate new visual input in a very fast, reliable, and sustainable way. PMID:22291676

  13. Fast Growing Plantations for Wood Production - Integration of Ecological Effects and Economic Perspectives.

    PubMed

    Bredemeier, Michael; Busch, Gerald; Hartmann, Linda; Jansen, Martin; Richter, Falk; Lamersdorf, Norbert P

    2015-01-01

    Biomass crops are perceived as a feasible means to substitute sizeable amounts of fossil fuel in the future. A prospect of CO2 reduction (resp. CO2 neutrality) is credited to biomass fuels, and thus a potential contribution to mitigate climate change. Short rotation coppices (SRCs) with fast growing poplar and willow trees are an option for producing high yields of woody biomass, which is suitable for both energetic and material use. One negative effect that comes along with the establishment of SRC may be a decrease in groundwater recharge, because high rates of transpiration and interception are anticipated. Therefore, it is important to measure, analyze, and model the effects of SRC-planting on landscape water budgets. To analyze the effects on the water budget, a poplar SRC plot was studied by measuring hydrological parameters to be used in the hydrological model WaSim. Results reveal very low or even missing ground water recharge for SRC compared to agricultural land use or grassland, especially succeeding dry years. However, this strong effect on plot level is moderated on the larger spatial scale of catchment level, for which the modeling was also performed. In addition to water, nutrient fluxes and budgets were studied. Nitrogen is still a crucial issue in today's agriculture. Intensive fertilization or increased applications of manure from concentrated livestock breeding are often leading to high loads of nitrate leaching, or enhanced N2O emissions to the atmosphere on arable crop fields. SRC or agroforestry systems on former crop land may offer an option to decrease such N losses, while simultaneously producing woody biomass. This is mainly due to the generally smaller N requirements of woody vegetation, which usually entail no need for any fertilization. The trees supply deep and permanent rooting systems, which can be regarded as a "safety net" to prevent nutrient leaching. Thus, SRC altogether can help to diminish N eutrophication. It is important to offer viable and attractive economic perspectives to farmers and other land managers besides of the potential ecological benefits of SRCs. For this reason, an integrated tool for scenario analysis was developed within the BEST project ("BEAST - Bio-Energy Allocation and Scenario Tool"). It combines ecological assessments with calculations of economic revenue as a basis for a participative regional dialog on sustainable land use and climate protection goals. Results show a substantial capacity for providing renewable energy from economically competitive arable SRC sites while generating ecological synergies. PMID:26106595

  14. Fast Growing Plantations for Wood Production – Integration of Ecological Effects and Economic Perspectives

    PubMed Central

    Bredemeier, Michael; Busch, Gerald; Hartmann, Linda; Jansen, Martin; Richter, Falk; Lamersdorf, Norbert P.

    2015-01-01

    Biomass crops are perceived as a feasible means to substitute sizeable amounts of fossil fuel in the future. A prospect of CO2 reduction (resp. CO2 neutrality) is credited to biomass fuels, and thus a potential contribution to mitigate climate change. Short rotation coppices (SRCs) with fast growing poplar and willow trees are an option for producing high yields of woody biomass, which is suitable for both energetic and material use. One negative effect that comes along with the establishment of SRC may be a decrease in groundwater recharge, because high rates of transpiration and interception are anticipated. Therefore, it is important to measure, analyze, and model the effects of SRC-planting on landscape water budgets. To analyze the effects on the water budget, a poplar SRC plot was studied by measuring hydrological parameters to be used in the hydrological model WaSim. Results reveal very low or even missing ground water recharge for SRC compared to agricultural land use or grassland, especially succeeding dry years. However, this strong effect on plot level is moderated on the larger spatial scale of catchment level, for which the modeling was also performed. In addition to water, nutrient fluxes and budgets were studied. Nitrogen is still a crucial issue in today’s agriculture. Intensive fertilization or increased applications of manure from concentrated livestock breeding are often leading to high loads of nitrate leaching, or enhanced N2O emissions to the atmosphere on arable crop fields. SRC or agroforestry systems on former crop land may offer an option to decrease such N losses, while simultaneously producing woody biomass. This is mainly due to the generally smaller N requirements of woody vegetation, which usually entail no need for any fertilization. The trees supply deep and permanent rooting systems, which can be regarded as a “safety net” to prevent nutrient leaching. Thus, SRC altogether can help to diminish N eutrophication. It is important to offer viable and attractive economic perspectives to farmers and other land managers besides of the potential ecological benefits of SRCs. For this reason, an integrated tool for scenario analysis was developed within the BEST project (“BEAST – Bio-Energy Allocation and Scenario Tool”). It combines ecological assessments with calculations of economic revenue as a basis for a participative regional dialog on sustainable land use and climate protection goals. Results show a substantial capacity for providing renewable energy from economically competitive arable SRC sites while generating ecological synergies. PMID:26106595

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

    SciTech Connect

    Farmanfarmaian, A. )

    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.

  16. Screening and Evaluation of Deleterious SNPs in APOE Gene of Alzheimer's Disease

    PubMed Central

    Masoodi, Tariq Ahmad; Al Shammari, Sulaiman A.; Al-Muammar, May N.; Alhamdan, Adel A.

    2012-01-01

    Introduction. Apolipoprotein E (APOE) is an important risk factor for Alzheimer's disease (AD) and is present in 30–50% of patients who develop late-onset AD. Several single-nucleotide polymorphisms (SNPs) are present in APOE gene which act as the biomarkers for exploring the genetic basis of this disease. The objective of this study is to identify deleterious nsSNPs associated with APOE gene. Methods. The SNPs were retrieved from dbSNP. Using I-Mutant, protein stability change was calculated. The potentially functional nonsynonymous (ns) SNPs and their effect on protein was predicted by PolyPhen and SIFT, respectively. FASTSNP was used for functional analysis and estimation of risk score. The functional impact on the APOE protein was evaluated by using Swiss PDB viewer and NOMAD-Ref server. Results. Six nsSNPs were found to be least stable by I-Mutant 2.0 with DDG value of >−1.0. Four nsSNPs showed a highly deleterious tolerance index score of 0.00. Nine nsSNPs were found to be probably damaging with position-specific independent counts (PSICs) score of ≥2.0. Seven nsSNPs were found to be highly polymorphic with a risk score of 3-4. The total energies and root-mean-square deviation (RMSD) values were higher for three mutant-type structures compared to the native modeled structure. Conclusion. We concluded that three nsSNPs, namely, rs11542041, rs11542040, and rs11542034, to be potentially functional polymorphic. PMID:22530123

  17. Screening and Evaluation of Deleterious SNPs in APOE Gene of Alzheimer's Disease.

    PubMed

    Masoodi, Tariq Ahmad; Al Shammari, Sulaiman A; Al-Muammar, May N; Alhamdan, Adel A

    2012-01-01

    Introduction. Apolipoprotein E (APOE) is an important risk factor for Alzheimer's disease (AD) and is present in 30-50% of patients who develop late-onset AD. Several single-nucleotide polymorphisms (SNPs) are present in APOE gene which act as the biomarkers for exploring the genetic basis of this disease. The objective of this study is to identify deleterious nsSNPs associated with APOE gene. Methods. The SNPs were retrieved from dbSNP. Using I-Mutant, protein stability change was calculated. The potentially functional nonsynonymous (ns) SNPs and their effect on protein was predicted by PolyPhen and SIFT, respectively. FASTSNP was used for functional analysis and estimation of risk score. The functional impact on the APOE protein was evaluated by using Swiss PDB viewer and NOMAD-Ref server. Results. Six nsSNPs were found to be least stable by I-Mutant 2.0 with DDG value of >-1.0. Four nsSNPs showed a highly deleterious tolerance index score of 0.00. Nine nsSNPs were found to be probably damaging with position-specific independent counts (PSICs) score of ≥2.0. Seven nsSNPs were found to be highly polymorphic with a risk score of 3-4. The total energies and root-mean-square deviation (RMSD) values were higher for three mutant-type structures compared to the native modeled structure. Conclusion. We concluded that three nsSNPs, namely, rs11542041, rs11542040, and rs11542034, to be potentially functional polymorphic. PMID:22530123

  18. 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)

  19. 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 ...

  20. The effect of antimicrobial agents on the ecology of the human intestinal microflora.

    PubMed

    Nord, C E

    1993-06-01

    The most common and significant cause of disturbances in the normal intestinal microflora is the administration of antimicrobial agents. The microflora can be influenced by antimicrobial agents because of incomplete absorption of any orally administered antimicrobial agent, secretion of an antimicrobial agent in the bile, or secretion from the intestinal mucosa. Administration of these agents may seriously disturb the balance of the normal intestinal microflora. This disturbance can cause bacterial overgrowth and emergence of resistant microorganisms which may lead to serious infections and also encourage transfer of resistance factors among bacteria. The ecological effects of penicillins, cephalosporins, monobactams, carbapenems, macrolides, clindamycin, tetracyclines, nitroimidazoles and quinolones on the human intestinal microflora are presented in this review article. PMID:8212506

  1. 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. )

    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.

  2. 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

  3. [Ecological Effects of Algae Blooms Cluster: The Impact on Chlorophyll and Photosynthesis of the Water Hyacinth].

    PubMed

    Liu, Guo-feng; He, Jun; Yang, Yi-zhong; Han, Shi-qun

    2015-08-01

    The response of chlorophyll and photosynthesis of water hyacinth leaves in different concentrations of clustered algae cells was studied in the simulation experiment, and the aim was to reveal the mechanism of the death of aquatic plants during algae blooms occurred through studying the physiological changes of the macrophytes, so as to play the full function of the ecological restoration of the plants. And results showed the dissolved oxygen quickly consumed in root zone of aquatic plants after algae blooms gathered and showed the lack of oxygen (DO < 0.2 g x L(-1)); and the ORP was lower than -100 mV after 1 d, and it declined to -200 mV at the end of the experiment. There were lots of nutrients releasing to the water after the algae cell died and concentration of DTN in treatment 1 and 2 were 44.49 mg x L(-1) and 111.32 mg x L(-1), and the content of DTP were 2.57 mg x L(-1) and 9.10 mg x L(-1), respectively. The NH4+ -N concentrations were as high as 32.99 mg x L(-1) and 51.22 mg x L(-1), and the root zone with the anoxia, strong reducing, higher nutrients environment had a serious stress effects to the aquatic plants. The macrophytes photosynthesis reduced quickly and the plant body damaged with the intimidation of higher NH4+ -N concentration (average content was 45.6 mg x L(-1)) and hypoxia after algae cell decomposed. The average net photosynthesis rate, leaf transpiration rate of the treatment 2 reduced to 3.95 micromol (M2 x S)(-1), 0.088 micromol x (m2 x s)(-1), and only were 0.18 times, 0.11 times of the control group, respectively, at the end of the experiment, the control group were 22 micromol x (m2 x s)(-1), 0.78 micromol x (M2 x s)(-1). Results indicated the algae bloom together had the irreversible damage to the aquatic plants. Also it was found large amounts of new roots and the old roots were dead in the treatment 1, but roots were all died in the treatment 2, and leaves were yellow and withered. Experiment results manifested that the serious environment caused by the algae blooms together was the main reason of the death of aquatic plants during the summer. So in the practice of ecological restoration, it should avoid the harm to the plant after the algae bloom cells gathered and decomposed, so as to play the purification function of the plant in the ecological rehabilitation project. PMID:26592017

  4. 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

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

    SciTech Connect

    Krivolutsky, D.

    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.

  6. Differential effects of ephemeral colonization by arbuscular mycorrhizal fungi in two Cuscuta species with different ecology.

    PubMed

    Behdarvandi, Behrang; Guinel, Frédérique C; Costea, Mihai

    2015-10-01

    Seedlings of parasitic Cuscuta species are autotrophic but can survive only a short period of time, during which they must locate and attach to a suitable host. They have an ephemeral root-like organ considered not a "true" root by most studies. In the present study, two species with contrasting ecology were examined: Cuscuta gronovii, a North American riparian species, and Cuscuta campestris, an invasive dodder that thrives in disturbed habitats. The morphology, structure, and absorptive capability of their root-like organ were compared, their potential for colonization by two species of arbuscular mycorrhizal fungi (AMF) was assessed, and the effect of the AMF on seedling growth and survival was determined. The root of both species absorbed water and interacted with AMF, but the two species exhibited dissimilar growth and survival patterns depending on the colonization level of their seedlings. The extensively colonized seedlings of C. gronovii grew more and survived longer than non-colonized seedlings. In contrast, the scarce colonization of C. campestris seedlings did not increase their growth or longevity. The differential growth responses of the AMF-colonized and non-colonized Cuscuta species suggest a mycorrhizal relationship and reflect their ecology. While C. gronovii roots have retained a higher ability to interact with AMF and are likely to take advantage of fungal communities in riparian habitats, the invasive C. campestris has largely lost this ability possibly as an adaptation to disturbed ecosystems. These results indicate that dodders have a true root, even if much reduced and ephemeral, that can interact with AMF. PMID:25720736

  7. Prediction of Deleterious Nonsynonymous Single-Nucleotide Polymorphism for Human Diseases

    PubMed Central

    Jiang, Rui

    2013-01-01

    The identification of genetic variants that are responsible for human inherited diseases is a fundamental problem in human and medical genetics. As a typical type of genetic variation, nonsynonymous single-nucleotide polymorphisms (nsSNPs) occurring in protein coding regions may alter the encoded amino acid, potentially affect protein structure and function, and further result in human inherited diseases. Therefore, it is of great importance to develop computational approaches to facilitate the discrimination of deleterious nsSNPs from neutral ones. In this paper, we review databases that collect nsSNPs and summarize computational methods for the identification of deleterious nsSNPs. We classify the existing methods for characterizing nsSNPs into three categories (sequence based, structure based, and annotation based), and we introduce machine learning models for the prediction of deleterious nsSNPs. We further discuss methods for identifying deleterious nsSNPs in noncoding variants and those for dealing with rare variants. PMID:23431257

  8. 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.

  9. Effects of College Major on Ecological Worldviews: A Comparison of Business, Science, and Other Students.

    ERIC Educational Resources Information Center

    Ridener, Larry R.

    1999-01-01

    Social science, science, and business majors and undecided students (n=168) received environmental-sociology instruction based on constructivism. Ecology attitudes of science and social science students changed the most. Science majors had higher scores than did business majors on the Ecological Worldview Scale. (SK)

  10. Biobehavioral mechanisms of topiramate's effects on alcohol use: an investigation pairing laboratory and ecological momentary assessments.

    PubMed

    Miranda, Robert; MacKillop, James; Treloar, Hayley; Blanchard, Alexander; Tidey, Jennifer W; Swift, Robert M; Chun, Thomas; Rohsenow, Damaris J; Monti, Peter M

    2016-01-01

    Topiramate reduces drinking, but little is known about the mechanisms that precipitate this effect. This double-blind randomized placebo-controlled study assessed the putative mechanisms by which topiramate reduces alcohol use among 96 adult non-treatment-seeking heavy drinkers in a laboratory-based alcohol cue reactivity assessment and in the natural environment using ecological momentary assessment methods. Topiramate reduced the quantity of alcohol heavy drinkers consumed on drinking days and reduced craving while participants were drinking but did not affect craving outside of drinking episodes in either the laboratory or in the natural environment. Topiramate did not alter the stimulant or sedative effects of alcohol ingestion during the ascending limb of the blood alcohol curve. A direct test of putative mechanisms of action using multilevel structural equation mediation models showed that topiramate reduced drinking indirectly by blunting alcohol-induced craving. These findings provide the first real-time prospective evidence that topiramate reduces drinking by reducing alcohol's priming effects on craving and highlight the importance of craving as an important treatment target of pharmacotherapy for alcoholism. PMID:25353306

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

    PubMed Central

    Caso, Margarita; Gonzlez-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 Nio 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 Nio 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 Nio conditions produce a marked increase in winter rainfall above 22 latitude, whereas La Nia 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 atmosphereocean 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

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

    USGS Publications Warehouse

    Harrison, S.; Damschen, E.I.; Grace, J.B.

    2010-01-01

    Downscalingfromthe predictions ofgeneral climatemodels 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 howvariation 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 complexmontane landscape (the SiskiyouMountains, 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 herbcommunity 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 andmoremodest changes, including increases in herbs of northern biogeographic affinity and in forest canopy cover. Our results provide communitylevel validation of predicted nonlinearities in climate change effects.

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

    USGS Publications Warehouse

    Harrison, Susan; Damschen, Ellen Ingman; 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 (1949/19512007/2009) 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 (5001.200 m above sea level) and primary upper montane to subalpine forests (1,5002,100 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.

  14. 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

  15. 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., 2012). A direct measure of EI - one that specifically accounts for the drainage from each impervious surface rather than using a generic reduction factor (e.g., Booth and Jackson, 1997; Wang et al., 2001) - has not previously been used in geomorphic investigations. In this paper, we advance on past studies by testing if EI is a stronger predictor than TI for urban-induced channel change.A second limitation of previous studies of urban-induced morphologic change is the common focus on channel dimensions (Chin, 2006). These are important for infrastructure and flood protection but do not necessarily have a strong mechanistic link to stream ecosystems. While some notable exceptions exist (Finkenbine et al., 2000; McBride and Booth, 2005), other geomorphic attributes are rarely investigated.This study examines how urbanization of a watershed can result in the impairment of a suite of geomorphic attributes of relevance to aquatic ecosystem condition, such as large wood, sediment availability, and structural and hydraulic complexity (of the bed, bank, and water column), represented by the following variables:

  16. 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.

  17. Animal behaviour shapes the ecological effects of ocean acidification and warming: moving from individual to community-level responses.

    PubMed

    Nagelkerken, Ivan; Munday, Philip L

    2016-03-01

    Biological communities are shaped by complex interactions between organisms and their environment as well as interactions with other species. Humans are rapidly changing the marine environment through increasing greenhouse gas emissions, resulting in ocean warming and acidification. The first response by animals to environmental change is predominantly through modification of their behaviour, which in turn affects species interactions and ecological processes. Yet, many climate change studies ignore animal behaviour. Furthermore, our current knowledge of how global change alters animal behaviour is mostly restricted to single species, life phases and stressors, leading to an incomplete view of how coinciding climate stressors can affect the ecological interactions that structure biological communities. Here, we first review studies on the effects of warming and acidification on the behaviour of marine animals. We demonstrate how pervasive the effects of global change are on a wide range of critical behaviours that determine the persistence of species and their success in ecological communities. We then evaluate several approaches to studying the ecological effects of warming and acidification, and identify knowledge gaps that need to be filled, to better understand how global change will affect marine populations and communities through altered animal behaviours. Our review provides a synthesis of the far-reaching consequences that behavioural changes could have for marine ecosystems in a rapidly changing environment. Without considering the pervasive effects of climate change on animal behaviour we will limit our ability to forecast the impacts of ocean change and provide insights that can aid management strategies. PMID:26700211

  18. Climate and Land Use Change Effects on Ecological Resources in Three Watersheds: A Synthesis Report (Final Report)

    EPA Science Inventory

    Cover of the Synthesis Report on Climate and Land Use Change <span class=Effects on Ecological Resources in Three Wa...

  19. 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...

  20. 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...

  1. Climate and Land Use Change Effects on Ecological Resources in Three Watersheds: A Synthesis Report (Final Report)

    EPA Science Inventory

    Cover of the Synthesis Report on Climate and Land Use Change <span class=Effects on Ecological Resources in Three Wa...

  2. 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 6.510(-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

  3. [Effects of global climate change on the ecological characteristics and biogeochemical significance of marine viruses--A review].

    PubMed

    Yang, Yunlan; Cai, Lanlan; Zhang, Rui

    2015-09-01

    As the most abundance biological agents in the oceans, viruses can influence the physiological and ecological characteristics of host cells through viral infections and lysis, and affect the nutrient and energy cycles of the marine food chain. Thus, they are the major players in the ocean biogeochemical processes. The problems caused by global climate changes, such as sea-surface warming, acidification, nutrients availability, and deoxygenation, have the potential effects on marine viruses and subsequently their ecological and biogeochemical function in the ocean. Here, we reviewed the potential impacts of global climate change on the ecological characteristics (e. g. abundance, distribution, life cycle and the host-virus interactions) and biogeochemical significance (e. g. carbon cycling) of marine viruses. We proposed that marine viruses should not be ignored in the global climate change study. PMID:26762022

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

    SciTech Connect

    Not Available

    1980-11-01

    This report is concerned with the potential health and ecological effects of the microwave beam from the microwave power transmission system (MPTS) of the satellite power system (SPS). The report is written in the form of a detailed critical review of selected scientific articles from the published literature on the biological effects of nonionizing electromagnetic radiation, followed by an assessment of the possible effects of the SPS, based on exposure values for the reference system (US DOE and NASA, 1978).

  5. 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.

  6. 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.

  7. Transboundary socio-ecological effects of a Marine Protected Area in the Southwest Atlantic.

    PubMed

    Lopes, Priscila F M; Silvano, Renato A M; Nora, Vinicius A; Begossi, Alpina

    2013-12-01

    Marine Protected Areas (MPAs) have been regarded as an alternative to protect natural resources and to improve fisheries. However, MPAs may also have negative socio-economic consequences on fishing communities. We aimed to check the effectiveness of a socially conflicting MPA in Brazil by assessing target reef fish biomass in islands inside (n=6) and outside (n=6) the MPA, fisheries' productivity (biomass), catch per unit of effort (CPUE), and fishers' socio-economic status (mainly fishers' income) in three fishing communities subjected to different degrees of influence (close, average, and long distance) of the MPA. The CPUE was higher in the fishing community that was further away from the MPA, fish biomass was higher in the islands located inside the MPA in the southern region and in the islands located outside the MPA in the northern region, while fishers were making the most money closest to the MPA, where conflicts are the highest, probably from practicing very intensive fisheries. This integrated approach showed that the studied MPA has not delivered ecological benefits, such as higher CPUE or more fish, while higher income closer to the MPA could not be clearly attributed to its effects. PMID:24213995

  8. The Subjective Effects of Alcohol-Tobacco Co-Use: An Ecological Momentary Assessment Investigation

    PubMed Central

    Piasecki, Thomas M.; Jahng, Seungmin; Wood, Phillip K.; Robertson, Brandon M.; Epler, Amee J.; Cronk, Nikole J.; Rohrbaugh, John W.; Heath, Andrew C.; Shiffman, Saul; Sher, Kenneth J.

    2011-01-01

    Alcohol and tobacco use covary at multiple levels of analysis, and co-use of the two substances may have profound health consequences. In order to characterize the motivationally relevant processes contributing to co-use, the current study used Ecological Momentary Assessment (EMA) to examine the subjective consequences of naturally occurring simultaneous use of alcohol and tobacco. Current smokers who reported frequently drinking alcohol (N = 259) monitored their daily experiences for 21 days using electronic diaries. Participants responded to prompted assessments and also initiated recordings when they smoked a cigarette or completed the first drink in a drinking episode. Momentary reports of smoking and alcohol consumption were associated with one another, and these effects remained after adjustment for occasion- and person-level covariates. When participants consumed alcohol, they reported increased pleasure and decreased punishment from the last cigarette. Smoking was associated with small increases in pleasure from the last drink. Ratings of buzzed and dizzy were synergistically affected by co-use of alcohol and tobacco. Co-use was also followed by higher levels of craving for both alcohol and tobacco. Results point to the importance of reward and incentive processes in ongoing drug use and suggest that alcohol intensifies real-time reports of the motivational consequences of smoking more strongly than smoking affects corresponding appraisals of alcohol effects. PMID:21443289

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

    PubMed Central

    2014-01-01

    Background Interactions 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. Results Our 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. Conclusions Previous 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

  10. Using observation-level random effects to model overdispersion in count data in ecology and evolution

    PubMed Central

    2014-01-01

    Overdispersion is common in models of count data in ecology and evolutionary biology, and can occur due to missing covariates, non-independent (aggregated) data, or an excess frequency of zeroes (zero-inflation). Accounting for overdispersion in such models is vital, as failing to do so can lead to biased parameter estimates, and false conclusions regarding hypotheses of interest. Observation-level random effects (OLRE), where each data point receives a unique level of a random effect that models the extra-Poisson variation present in the data, are commonly employed to cope with overdispersion in count data. However studies investigating the efficacy of observation-level random effects as a means to deal with overdispersion are scarce. Here I use simulations to show that in cases where overdispersion is caused by random extra-Poisson noise, or aggregation in the count data, observation-level random effects yield more accurate parameter estimates compared to when overdispersion is simply ignored. Conversely, OLRE fail to reduce bias in zero-inflated data, and in some cases increase bias at high levels of overdispersion. There was a positive relationship between the magnitude of overdispersion and the degree of bias in parameter estimates. Critically, the simulations reveal that failing to account for overdispersion in mixed models can erroneously inflate measures of explained variance (r2), which may lead to researchers overestimating the predictive power of variables of interest. This work suggests use of observation-level random effects provides a simple and robust means to account for overdispersion in count data, but also that their ability to minimise bias is not uniform across all types of overdispersion and must be applied judiciously. PMID:25320683

  11. 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 landLubotan 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.

  12. 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...

  13. Using species ecological traits to understand the disturbance effects of fine sediment in river channels

    NASA Astrophysics Data System (ADS)

    Gibbins, C.; Buendia, C.; Vericat, D.; Batalla, R. J.

    2012-12-01

    A large volume of researched is now published under the banner of eco-hydrology (or hydro-ecology). However, much of this work either lacks ecological data (i.e. it is essentially hydrology or fluvial geomorphology, with post-hoc discussion of ecological implications) or the links between the hydrology and the ecology are established using only correlative approaches. Specifically, eco-hydrology research has been criticized for failing to present mechanistic or ecological explanations for observed correlations and patterns. Such criticisms have lead to heated debate and calls for the ecology to feature more prominently in eco-hydrology research. In this paper we use species ecological traits to establish causal links between the fine sediment content of natural river channels and the structure of their invertebrate assemblages. Spatial variation in assemblage taxonomic composition across the study catchment followed a nested pattern, with species found in taxon poor locations being a subset of those found in taxon rich ones. These patterns of nestedness were significantly related to the fine sediment content of the bed. Trait analysis of the species data suggests that fine sediment selects for specific morphological, behavioural and life-history traits, with species lacking such traits rapidly disappearing from locations with excessive fines. Thus, the prevalence of different adaptive traits explains mechanistically the observed patterns of nestedness. We show how multiple traits can be incorporated into metrics that can be used as assessment or monitoring tools. These metrics have the advantage that they represent relationships between organisms and their environment in ways that explicitly capture the underlying ecological mechanisms.

  14. Ecological Misconceptions.

    ERIC Educational Resources Information Center

    Munson, Bruce H.

    1994-01-01

    Presents a summary of the research literature on students' ecological conceptions and the implications of misconceptions. Topics include food webs, ecological adaptation, carrying capacity, ecosystem, and niche. (Contains 35 references.) (MKR)

  15. 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.

  16. 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.

  17. Ecological effects of contaminants in McCoy Branch, 1991--1993

    SciTech Connect

    Ryon, M.G.

    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.

  18. 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

  19. Open top culverts as an alternative drainage system to minimize ecological effects in earth roads.

    NASA Astrophysics Data System (ADS)

    Garca, Jose L.; Elorrieta, Jose; Robredo, Jose C.; Garca, Ricardo; Garca, 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.

  20. Some effects of giant Andean stem-rosettes on ground microclimate, and their ecological significance

    NASA Astrophysics Data System (ADS)

    Prez, Francisco L.

    1989-06-01

    The effect of giant Andean stem-rosettes ( Coespeletia lutescens) on air and soil temperatures was studied in the Pramo de Piedras Blancas (Venezuela) at 4265 and 4385 m altitude during the dry season, which is the coldest season in this tropical mountain area. Maximum air temperatures beneath a plant canopy were only slightly higher than in the open. Minimum temperatures below the stem-rosettes were 4.7 to 7.0C higher than in the open. This substantially reduced the intensity of nightly freezing. Soil temperature minima at 20 cm depth were 2.4 to 4.2C higher below plants, but maxima were somewhat lower than in bare soil. These microclimatic alterations are ecologically significant for stemprosette seedlings, which should have a higher probability of survival due to the reduced frequency of frost and needle ice formation below large plants. Warmer soils at night should also result in greater water uptake by seedlings during the early morning hours, thus reducing dry-season mortality.

  1. 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.

  2. Ecological effects of the insecticide imidacloprid and a pollutant from antidandruff shampoo in experimental rice fields.

    PubMed

    Sanchez-Bayo, Francisco; Goka, Kouichi

    2006-06-01

    Ecological changes caused by the insecticide imidacloprid and a pollutant from antidandruff shampoos (zinc pyrithione) were monitored in experimental paddies throughout a cultivation period. A total of 88 species were observed, with 54 of them aquatic. Plankton, nekton, benthic, and terrestrial communities from imidacloprid fields had significantly less abundance of organisms compared with control and shampoo-treated fields, either for the entire period or during early stages. The absence of Chironomus yoshimatsui and typical paddy ostracods from imidacloprid fields was most remarkable; as a consequence, green algae blooms (Spirogyra sp.) developed, which in turn hampered the establishment of weeds. Such changes occurred while residues of imidacloprid in water were present at levels greater than 1 microg/L. The overall diversity was similar in all fields and increased constantly until the end of the study. Phytophagous insects dominated in early communities, gradually giving way to predators and scavengers during late stages, but imidacloprid fields had a lower proportion of the latter trophic group. Multivariate analyses helped to describe and differentiate the communities between treatments and control. Hazard- and risk-assessment methods overestimated the effects of zinc pyrithione but failed to predict imidacloprid impacts, probably because of deficiencies in the exposure and relevant toxicity data used. PMID:16764489

  3. Biological control via "ecological" damping: An approach that attenuates non-target effects.

    PubMed

    Parshad, Rana D; Quansah, Emmanuel; Black, Kelly; Beauregard, Matthew

    2016-03-01

    In this work we develop and analyze a mathematical model of biological control to prevent or attenuate the explosive increase of an invasive species population, that functions as a top predator, in a three-species food chain. We allow for finite time blow-up in the model as a mathematical construct to mimic the explosive increase in population, enabling the species to reach "disastrous", and uncontrollable population levels, in a finite time. We next improve the mathematical model and incorporate controls that are shown to drive down the invasive population growth and, in certain cases, eliminate blow-up. Hence, the population does not reach an uncontrollable level. The controls avoid chemical treatments and/or natural enemy introduction, thus eliminating various non-target effects associated with such classical methods. We refer to these new controls as "ecological damping", as their inclusion dampens the invasive species population growth. Further, we improve prior results on the regularity and Turing instability of the three-species model that were derived in Parshad et al. (2014). Lastly, we confirm the existence of spatiotemporal chaos. PMID:26767801

  4. 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

  5. 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…

  6. 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

  7. 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

  8. Ecological effects of sulfur dioxide, fluorides, and minor air pollutants: recent trends and research needs.

    PubMed

    Cape, J Neil; Fowler, David; Davison, Alan

    2003-06-01

    The regulation of the emissions of 'traditional' primary air pollutants (fluorides, sulfur dioxide) has changed the pattern of exposure of ecological systems, with greatly reduced exposure close to sources, but with a smaller effect in some remote areas. Measurements show that recovery is occurring at some sites, in fresh water chemistry (reduced acidity) and in sensitive biota (sustainable fish populations). However, the pattern of change in exposure has not always been simply related to emission reductions. An understanding of responses to recent changes will improve our predictions of the response to future emission changes, both locally and globally. As exposure to 'traditional' pollutants is reduced, the potential for other pollutants to have effects becomes more evident. In the aqueous phase, we need to understand the role of soluble and suspended organics, but this also means explicit recognition of the possibility of phase exchange, and the role of photolytic reactions on plant, soil, and water surfaces. Do highly reactive free radicals in the atmosphere, formed by the action of sunlight on volatile organic compounds, have direct effects on plants? Organic compounds and heavy metals may be bioactive as gases and particles, but for many potentially toxic compounds, the experimental evidence for biotic response is very limited. To evaluate the potential effects of pollutants, we need to understand the pathways by which airborne pollutants enter and react within ecosystems. For vegetation, we have to consider bidirectional fluxes, and distinguish among uptake through stomata, through leaf surfaces, or through roots. There are several challenges for the future. (1) Can we devise experiments that permit exposure of vegetation to gases, particles, and/or aqueous pollutants at 'realistic' concentrations? (2) Can we include the potential interactions with photolytically derived free radicals, and the dynamics of exchange? (3) How do we allow for responses to pollutant mixtures, or the simultaneous exposure to pollutants in gas, particle, and aqueous phases? The recognition of the importance of the dynamic exchange of pollutants between phases will be the key to the development of effective experimental approaches to evaluating cause-effect relationships between pollutant mixtures and ecosystem responses. PMID:12676208

  9. Ecological energetics of the desert tortoise (Gopherus Agassizii): Effects of rainfall and drought

    SciTech Connect

    Peterson, C.C.

    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.

  10. 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...

  11. Handbook for Ecology Action.

    ERIC Educational Resources Information Center

    Eber, Ronald

    This handbook has been compiled to aid concerned individuals and ecology groups more adequately define their goals, initiate good programs, and take effective action. It examines the ways a group of working individuals can become involved in action programs for ecological change. Part 1 deals with organization, preliminary organizing, structuring,

  12. Disentangling the effects of geographic and ecological isolation on genetic differentiation.

    PubMed

    Bradburd, Gideon S; Ralph, Peter L; Coop, Graham M

    2013-11-01

    Populations can be genetically isolated both by geographic distance and by differences in their ecology or environment that decrease the rate of successful migration. Empirical studies often seek to investigate the relationship between genetic differentiation and some ecological variable(s) while accounting for geographic distance, but common approaches to this problem (such as the partial Mantel test) have a number of drawbacks. In this article, we present a Bayesian method that enables users to quantify the relative contributions of geographic distance and ecological distance to genetic differentiation between sampled populations or individuals. We model the allele frequencies in a set of populations at a set of unlinked loci as spatially correlated Gaussian processes, in which the covariance structure is a decreasing function of both geographic and ecological distance. Parameters of the model are estimated using a Markov chain Monte Carlo algorithm. We call this method Bayesian Estimation of Differentiation in Alleles by Spatial Structure and Local Ecology (BEDASSLE), and have implemented it in a user-friendly format in the statistical platform R. We demonstrate its utility with a simulation study and empirical applications to human and teosinte data sets. PMID:24102455

  13. 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...

  14. 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

  15. 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.

  16. Effects of a herbicide-insecticide mixture in freshwater microcosms: risk assessment and ecological effect chain.

    PubMed

    Van den Brink, Paul J; Crum, Steven J H; Gylstra, Ronald; Bransen, Fred; Cuppen, Jan G M; Brock, Theo C M

    2009-01-01

    Effects of chronic application of a mixture of the herbicide atrazine and the insecticide lindane were studied in indoor freshwater plankton-dominated microcosms. The macroinvertebrate community was seriously affected at all but the lowest treatment levels, the zooplankton community at the three highest treatment levels, with crustaceans, caddisflies and dipterans being the most sensitive groups. Increased abundance of the phytoplankton taxa Cyclotella sp. was found at the highest treatment level. Threshold levels for lindane, both at population and community level, corresponded well with those reported in the literature. Atrazine produced fewer effects than expected, probably due to decreased grazer stress on the algae as a result of the lindane application. The safety factors set by the Uniform Principles for individual compounds were also found to ensure protection against chronic exposure to a mixture of a herbicide and insecticide at community level, though not always at the population level. PMID:18757125

  17. Extracellular localization of galectin-3 has a deleterious role in joint tissues.

    PubMed

    Janelle-Montcalm, Audre; Boileau, Christelle; Poirier, Franoise; Pelletier, Jean-Pierre; Guvremont, Mlanie; Duval, Nicolas; Martel-Pelletier, Johanne; Reboul, Pascal

    2007-01-01

    In this study we examine the extracellular role of galectin-3 (gal-3) in joint tissues. Following intra-articular injection of gal-3 or vehicle in knee joints of mice, histological evaluation of articular cartilage and subchondral bone was performed. Further studies were then performed using human osteoarthritic (OA) chondrocytes and subchondral bone osteoblasts, in which the effect of gal-3 (0 to 10 microg/ml) was analyzed. Osteoblasts were incubated in the presence of vitamin D3 (50 nM), which is an inducer of osteocalcin, encoded by an osteoblast terminal differentiation gene. Genes of interest mainly expressed in either chondrocytes or osteoblasts were analyzed with real-time RT-PCR and enzyme immunoassays. Signalling pathways regulating osteocalcin were analyzed in the presence of gal-3. Intra-articular injection of gal-3 induced knee swelling and lesions in both cartilage and subchondral bone. On human OA chondrocytes, gal-3 at 1 microg/ml stimulated ADAMTS-5 expression in chondrocytes and, at higher concentrations (5 and 10 microg/ml), matrix metalloproteinase-3 expression. Experiments performed with osteoblasts showed a weak but bipolar effect on alkaline phosphatase expression: stimulation at 1 microg/ml or inhibition at 10 microg/ml. In the absence of vitamin D3, type I collagen alpha 1 chain expression was inhibited by 10 microg/ml of gal-3. The vitamin D3 induced osteocalcin was strongly inhibited in a dose-dependent manner in the presence of gal-3, at both the mRNA and protein levels. This inhibition was mainly mediated by phosphatidylinositol-3-kinase. These findings indicate that high levels of extracellular gal-3, which could be encountered locally during the inflammatory process, have deleterious effects in both cartilage and subchondral bone tissues. PMID:17326835

  18. Extracellular localization of galectin-3 has a deleterious role in joint tissues

    PubMed Central

    Janelle-Montcalm, Audre; Boileau, Christelle; Poirier, Franoise; Pelletier, Jean-Pierre; Guvremont, Mlanie; Duval, Nicolas; Martel-Pelletier, Johanne; Reboul, Pascal

    2007-01-01

    In this study we examine the extracellular role of galectin-3 (gal-3) in joint tissues. Following intra-articular injection of gal-3 or vehicle in knee joints of mice, histological evaluation of articular cartilage and subchondral bone was performed. Further studies were then performed using human osteoarthritic (OA) chondrocytes and subchondral bone osteoblasts, in which the effect of gal-3 (0 to 10 ?g/ml) was analyzed. Osteoblasts were incubated in the presence of vitamin D3 (50 nM), which is an inducer of osteocalcin, encoded by an osteoblast terminal differentiation gene. Genes of interest mainly expressed in either chondrocytes or osteoblasts were analyzed with real-time RT-PCR and enzyme immunoassays. Signalling pathways regulating osteocalcin were analyzed in the presence of gal-3. Intra-articular injection of gal-3 induced knee swelling and lesions in both cartilage and subchondral bone. On human OA chondrocytes, gal-3 at 1 ?g/ml stimulated ADAMTS-5 expression in chondrocytes and, at higher concentrations (5 and 10 ?g/ml), matrix metalloproteinase-3 expression. Experiments performed with osteoblasts showed a weak but bipolar effect on alkaline phosphatase expression: stimulation at 1 ?g/ml or inhibition at 10 ?g/ml. In the absence of vitamin D3, type I collagen alpha 1 chain expression was inhibited by 10 ?g/ml of gal-3. The vitamin D3induced osteocalcin was strongly inhibited in a dose-dependent manner in the presence of gal-3, at both the mRNA and protein levels. This inhibition was mainly mediated by phosphatidylinositol-3-kinase. These findings indicate that high levels of extracellular gal-3, which could be encountered locally during the inflammatory process, have deleterious effects in both cartilage and subchondral bone tissues. PMID:17326835

  19. Toward a sustainable future: Addressing the long-term effects of motor vehicle transportation on climate and ecology. Special report

    SciTech Connect

    1997-11-01

    Contents: Executive Summary; Sustainability and Transportation; Trends and Outlook in Motor Vehicle Transportation; Carbon Dioxide Buildup and Motor Vehicle Transportation; Cumulative Ecological Effects of Vehicle Emissions and Infrastructure; Summary Assessment and Implications for Research and Policy Making; Appendixes; Assumptions, Calculations, and Data Sources for Baseline and Hypothetical Scenarios; Federal Research on Alternative Transportation Fuels and Vehicles; Statement of David G. Burwell, and Study Committee Biographical Information.

  20. 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.

  1. Climate change effects on runoff, catchment phosphorus loading and lake ecological state, and potential adaptations.

    PubMed

    Jeppesen, Erik; Kronvang, Brian; Meerhoff, Mariana; Sndergaard, Martin; Hansen, Kristina M; Andersen, Hans E; Lauridsen, Torben L; Liboriussen, Lone; Beklioglu, Meryem; Ozen, Arda; Olesen, Jrgen E

    2009-01-01

    Climate change may have profound effects on phosphorus (P) transport in streams and on lake eutrophication. Phosphorus loading from land to streams is expected to increase in northern temperate coastal regions due to higher winter rainfall and to a decline in warm temperate and arid climates. Model results suggest a 3.3 to 16.5% increase within the next 100 yr in the P loading of Danish streams depending on soil type and region. In lakes, higher eutrophication can be expected, reinforced by temperature-mediated higher P release from the sediment. Furthermore, a shift in fish community structure toward small and abundant plankti-benthivorous fish enhances predator control of zooplankton, resulting in higher phytoplankton biomass. Data from Danish lakes indicate increased chlorophyll a and phytoplankton biomass, higher dominance of dinophytes and cyanobacteria (most notably of nitrogen fixing forms), but lower abundance of diatoms and chrysophytes, reduced size of copepods and cladocerans, and a tendency to reduced zooplankton biomass and zooplankton:phytoplankton biomass ratio when lakes warm. Higher P concentrations are also seen in warm arid lakes despite reduced external loading due to increased evapotranspiration and reduced inflow. Therefore, the critical loading for good ecological state in lakes has to be lowered in a future warmer climate. This calls for adaptation measures, which in the northern temperate zone should include improved P cycling in agriculture, reduced loading from point sources, and (re)-establishment of wetlands and riparian buffer zones. In the arid Southern Europe, restrictions on human use of water are also needed, not least on irrigation. PMID:19704137

  2. [Field investigation on ecological effect of windbreak and soil erosion reduction from sandy grasslands].

    PubMed

    Zhang, Hua; Li, Feng-rui; Fu, Qian-ke; L, Zi-jun

    2004-03-01

    Through field observation of the variation of vegetational characteristics and sand transported rate in sandy grasslands at different levels of desertification during the spring erosive period, the ecological effects of windbreak and soil erosion reduction from sandy grasslands of the Horqin Sandy Land were studied. The results showed that vegetational coverage varied obviously from 0.3% in the shifting sand land of the severe desertification to 16% in the fixed sand land of the least desertification in mid May. Increases in vegetational coverage led to a corresponding increase in surface roughness length from 0.013 cm in the shifting sand land to 0.111 cm in the fixed sand land, thus resulting in an increase in friction velocity from 0.272 m.s-1 in the shifting sand land to 0.823 m.s-1 in the fixed sand land and a decrease in mean wind speed near the surfaces from 7.0 m.s-1 in the shifting sand land to 3.8 m.s-1 in the fixed sand land. This in turn led to a reduction in the total sand transported rate within the height of 0-20 cm from 88.8 g.(h.cm2)-1 in the shifting sand land to 1.6 g.(h.cm2)-1 in the fixed sand land. When the experimental data were analyzed by regressing the total sand transported rate (Q) against vegetational coverage (VC), a model of predictive regression was developed: Q = 3.93 + 93.66e-0.60VC(R2 = 0.893, p < 0.0001, n = 40). PMID:15202248

  3. 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

  4. GENERIC ECOLOGICAL ASSESSMENT ENDPOINTS (GEAE) FOR ECOLOGICAL RISK ASSESSMENT

    EPA Science Inventory

    Ecological risk assessment is a process for evaluating the likelihood that adverse ecological effects may occur or are occurring as a result of exposure to one or more stressors. A critical early step in conducting an ecological risk assessment is to select assessment endpoints. ...

  5. 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 important economic impacts, at least locally. It is concluded that levels of total nitrogen lower than 0.5-1.0 mg TN/L could prevent aquatic ecosystems (excluding those ecosystems with naturally high N levels) from developing acidification and eutrophication, at least by inorganic nitrogen pollution. Those relatively low TN levels could also protect aquatic animals against the toxicity of inorganic nitrogenous compounds since, in the absence of eutrophication, surface waters usually present relatively high concentrations of dissolved oxygen, most inorganic reactive nitrogen being in the form of nitrate. Additionally, human health and economy would be safer from the adverse effects of inorganic nitrogen pollution. PMID:16781774

  6. The ecological effect of acid conditions and precipitation of hydrous metal oxides in a Rocky Mountain stream

    USGS Publications Warehouse

    McKnight, Diane M.; Feder, G.L.

    1984-01-01

    Periphyton and benthic invertebrates assemblages were studied at the confluence of two Rocky Mountain streams, Deer Creek and the Snake River near Montezuma, Colorado. Upstream from the confluence the Snake River is acidic and enriched in dissolved trace metals, while Deer Creek is a typical Rocky Mountain stream. In the Snake River, downstream from the confluence, the pH increases and hydrous metal oxides precipitate and cover the streambed. The algal and benthic invertebrate communities in the upstream reaches of the Snake River and in Deer Creek were very different. A liverwort, Scapania undulata var. undulata, was abundant in the Snake River, and although periphyton were very sparse, there were as many benthic invertebrates as in Deer Creek. Downstream from the confleunce, the precipitation of hydrous metal oxides greatly decreased the abundance of periphyton and benthic invertebrates. This study shows that in streams metal precipitates covering the streambed may have a more deleterious effect on stream communities than high metal-ion activities. ?? 1984 Dr. W. Junk Publishers.

  7. Complex Deleterious Interactions Associated with Malic Enzyme May Contribute to Reproductive Isolation in the Copepod Tigriopus californicus

    PubMed Central

    Willett, Christopher S.

    2011-01-01

    Dobzhansky-Muller incompatibilities can result from the interactions of more than a single pair of interacting genes and there are several different models of how such complex interactions can be structured. Previous empirical work has identified complex conspecific epistasis as a form of complex interaction that has contributed to postzygotic reproductive isolation between taxa, but other forms of complexity are also possible. Here, I probe the genetic basis of reproductive isolation in crosses of the intertidal copepod Tigriopus californicus by looking at the impact of markers in genes encoding metabolic enzymes in F2 hybrids. The region of the genome associated with the locus ME2 is shown to have strong, repeatable impacts on the fitness of hybrids in crosses and epistatic interactions with another chromosomal region marked by the GOT2 locus in one set of crosses. In a cross between one of these populations and a third population, these two regions do not appear to interact despite the continuation of a large effect of the ME2 region itself in both crosses. The combined results suggest that the ME2 chromosomal region is involved in incompatibilities with several unique partners. If these deleterious interactions all stem from the same factor in this region, that would suggest a different form of complexity from complex conspecific epistasis, namely, multiple independent deleterious interactions stemming from the same factor. Confirmation of this idea will require more fine-scale mapping of the interactions of the ME2 region of the genome. PMID:21731664

  8. A case of early onset rectal cancer of Lynch syndrome with a novel deleterious PMS2 mutation.

    PubMed

    Nomura, Sachio; Fujimoto, Yoshiya; Yamamoto, Noriko; Sato, Yuri; Ashihara, Yuumi; Kita, Mizuho; Yamaguchi, Junya; Ishikawa, Yuichi; Ueno, Masashi; Arai, Masami

    2015-10-01

    Heterozygous deleterious mutation of the PMS2 gene is a cause of Lynch syndrome, an autosomal dominant cancer disease. However, the frequency of PMS2 mutation is rare compared with that of the other causative genes; MSH2, MLH1 and MSH6. PMS2 mutation has so far only been reported once from a Japanese facility. Detection of PMS2 mutation is relatively complicated due to the existence of 15 highly homologous pseudogenes, and its gene conversion event with the pseudogene PMS2CL. Therefore, for PMS2 mutation analysis, it is crucial to clearly distinguish PMS2 from its pseudogenes. We report here a novel deleterious 11 bp deletion mutation of exon 11 of PMS2 distinguished from PMS2CL in a 34-year-old Japanese female with rectal cancer. PMS2 mutated at c.1492del11 results in a truncated 500 amino acid protein rather than the wild-type protein of 862 amino acids. This is supported by the fact that, although there is usually concordance between MLH1 and PMS2 expression, cells were immunohistochemically positive for MLH1, whereas PMS2 could not be immunohistochemically stained using an anti-C-terminal PMS2 antibody, or effective PMS2 mRNA degradation with NMD caused by the frameshift mutation. PMID:26232782

  9. Modeling hydrodynamics, water quality, and benthic processes to predict ecological effects in Narragansett Bay

    EPA Science Inventory

    The environmental fluid dynamics code (EFDC) was used to study the three dimensional (3D) circulation, water quality, and ecology in Narragansett Bay, RI. Predictions of the Bay hydrodynamics included the behavior of the water surface elevation, currents, salinity, and temperatur...

  10. 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...

  11. 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 ...

  12. Conflict Resolution Style Among Mexican Children: Examining Urbanization and Ecology Effects.

    ERIC Educational Resources Information Center

    Kagan, Spencer; And Others

    1981-01-01

    Tested the hypothesis that a consequence of increased urbanization is increased competitiveness. Measured Mexican children's preferred responses to conflict. Results did not support the urban-rural dichotomy but suggested the need for a more differentiated classification of the social ecology of settings. (Author/MK)

  13. Effects of feed additives and mixed eimeria species infection on intestinal microbial ecology of broilers.

    PubMed

    Hume, M E; Clemente-Hernndez, S; Oviedo-Rondn, E O

    2006-12-01

    Evaluation of digestive microbial ecology is necessary to understand effects of growth-promoting feed. In the current study, the dynamics of intestinal microbial communities (MC) were examined in broilers fed diets supplemented with a combination of antibiotic (bacitracin methylene disalicylate) and ionophore (Coban 60), and diets containing 1 of 2 essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated uninfected control; 2) unmedicated infected control; 3) feed additives monensin (bacitracin methylene disalicylate) + monensin (Coban 60; AI); 4) EO blend CP; and 5) EO blend CA. Additives were mixed into a basal feed mixture, and EO were adjusted to 100 ppm. Chicks were infected by oral gavage at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before and 7 d after challenge; 2 samples each were pooled to give a final number of 6 samples total; and all pooled samples were frozen until used for DNA extraction. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of PCR amplicon or band patterns indicated MC differences due to intestinal location, feed additives, and cocci challenge. Essential oil blends CP and CA affected MC in all gut sections. Each EO had different effects over MC, and they differed in most instances from the AI group. The cocci challenge caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). Diets supplemented with CP supported higher SC between pre- and postchallenge MC (89.9, 83.3, and 76.4%) than AI (81.8., 57.4, and 60.0%). We concluded that mixed coccidia challenge caused drastic shifts in MC. These EO blends modulated MC better than AI, avoiding drastic shifts after a mixed challenge. PMID:17135664

  14. [Effects of nitrogen deposition on leaf physiological and ecological characteristics of Lindera aggregata seedlings].

    PubMed

    Wang, Qiang; Jin, Ze-Xin; Peng, Li-Qiong

    2012-10-01

    From June 2010 to July 2011, a pot experiment was conducted to explore the effects of nitrogen deposition on the leaf physiological and ecological characteristics of Lindera aggregate seedlings. Three levels of NH4NO3, i. e., low-N (2 g x m(-2) x a(-1)), medium-N (8 g x m(-2) x a(-1)), and high-N (32 g x m(-2) x a(-1)) , were added to simulate nitrogen deposition, and the seedling leaf photosynthesis, relative chlorophyll content, chlorophyll fluorescence parameters, membrane lipid peroxidation, and antioxidant enzyme activities were determined. After one-year treatment, the daily mean values of the net photosynthetic rate (P)n)) and the maximum net photosynthetic rate (P(n max)) at low, medium and high levels of NH4 NO3 addition were 47.0%, 117.8% and 41.2%, and 82.6%, 191.3% and 152.2% higher than those of the control (no NH4 NO3 addition), respectively, with the highest values at medium level of NH4NO3 addition. The intercellular CO2 concentration, daily mean stomatal conductance, light saturation point, and apparent quantum yield in the three treatments of NH4NO3 addition were all higher than those of the control, and the dark respiration rate was the highest in treatment high-N. The relative chlorophyll content was the highest in treatment medium-N, followed by in treatment high-N, and had no significant difference between treatment low-N and the control. The chlorophyll fluorescence parameters varied with the levels of NH4NO3 addition. The PS II primary chemical efficiency (F(v)/F(m)) and PS II potential activity (F(v)/F(o)) were the lowest in treatment high-N, the superoxide dismutase activity was higher in nitrogen addition treatments than in the control, and the peroxidase activity, malonydialdehyde content, and membrane permeability were the highest in treatment high-N. All the results suggested that nitrogen deposition enhanced the photosynthetic ability of L. aggregata seedlings, with the most obvious effects in treatment medium-N, and altered the other physiological traits of the seedlings to different degrees. PMID:23359938

  15. 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

  16. Parapoxvirus causes a deleterious disease in red squirrels associated with UK population declines.

    PubMed

    Tompkins, Daniel M; Sainsbury, A W; Nettleton, P; Buxton, D; Gurnell, J

    2002-03-01

    The disease implications of novel pathogens need to be considered when investigating the ecological impact of species translocations on native fauna. Traditional explanations based on competition or predation may often not be the whole story. Evidence suggests that an emerging infectious disease, caused by a parapoxvirus, may be a significant component of the impact that the introduced grey squirrel has had on UK red squirrel populations. Here we validate the potential role of parapoxvirus by proving that the virus is highly pathogenic in the red squirrel while having no detectable effect on grey squirrel health. PMID:11886647

  17. The effects of intercooling and regeneration on the thermo-ecological performance analysis of an irreversible-closed Brayton heat engine with variable-temperature thermal reservoirs

    NASA Astrophysics Data System (ADS)

    Salim Sogut, Oguz; Ust, Yasin; Sahin, Bahri

    2006-11-01

    A thermo-ecological performance analysis of an irreversible intercooled and regenerated closed Brayton heat engine exchanging heat with variable-temperature thermal reservoirs is presented. The effects of intercooling and regeneration are given special emphasis and investigated in detail. A comparative performance analysis considering the objective functions of an ecological coefficient of performance, an ecological function proposed by Angulo-Brown and power output is also carried out. The results indicate that the optimal total isentropic temperature ratio and intercooling isentropic temperature ratio at the maximum ecological coefficient of performance conditions (ECOPmax) are always less than those of at the maximum ecological function ( \\dot {E}_{\\max } ) and the maximum power output conditions ( \\dot {W}_{\\max } ) leading to a design that requires less investment cost. It is also concluded that a design at ECOPmax conditions has the advantage of higher thermal efficiency and a lesser entropy generation rate, but at the cost of a slight power loss.

  18. 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

  19. ECOLOGICAL RISK ASSESSMENT WORKSHOP

    EPA Science Inventory

    As ecological risk assessment evolves, it is moving beyond focus on single species toward addressing multiple species and their interactions, and from assessing effects of simple chemical toxicity to the cumulative impacts of multiple interacting chemical, physical, and biologica...

  20. 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...

  1. 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.

  2. 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 (β-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.

  3. 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.

  4. Ecological restoration and its effects on a regional climate: the source region of the Yellow River, China.

    PubMed

    Li, Zhouyuan; Liu, Xuehua; Niu, Tianlin; Kejia, De; Zhou, Qingping; Ma, Tianxiao; Gao, Yunyang

    2015-05-19

    The source region of the Yellow River, China, experienced degradation during the 1980s and 1990s, but effective ecological restoration projects have restored the alpine grassland ecosystem. The local government has taken action to restore the grassland area since 1996. Remote sensing monitoring results show an initial restoration of this alpine grassland ecosystem with the structural transformation of land cover from 2000 to 2009 as low- and high-coverage grassland recovered. From 2000 to 2009, the low-coverage grassland area expanded by over 25% and the bare soil area decreased by approximately 15%. To examine the relationship between ecological structure and function, surface temperature (Ts) and evapotranspiration (ET) levels were estimated to study the dynamics of the hydro-heat pattern. The results show a turning point in approximately the year 2000 from a declining ET to a rising ET, eventually reaching the 1990 level of approximately 1.5 cm/day. We conclude that grassland coverage expansion has improved the regional hydrologic cycle as a consequence of ecological restoration. Thus, we suggest that long-term restoration and monitoring efforts would help maintain the climatic adjustment functions of this alpine grassland ecosystem. PMID:25894303

  5. Effects on the ecological health of a stream community due to wastewater treatment plant modifications

    SciTech Connect

    Murray, M.S.; Yates, L.T.; Danis, C.M.

    1994-12-31

    A residential community`s wastewater treatment plant effluent is the only point source discharge to the upper watershed of a small eastern Pennsylvania trout stream. Surveys of water quality, benthic macroinvertebrate and fish populations were conducted prior to, and for a two year period subsequent to installation of a Sequencing Batch Reactor (SBR) system in the community`s wastewater treatment plant. Evaluation of water chemistry, benthic macroinvertebrate community composition, and fish populations indicated that the ecological health of the stream improved almost immediately upon implementation of SBR treatment, but declined when the plant experienced nitrification problems. The plant resumed normal function for a time, followed by additional nitrification difficulties. The study includes an evaluation of the sensitivity of standard aquatic ecological indicators to an intermittent stressor. In particular, a comparison of benthic macroinvertebrate community indices is presented.

  6. 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.

  7. 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

  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. 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

  10. The ecological effects of individual exposures and nonlinear disease dynamics in populations.

    PubMed Central

    Koopman, J S; Longini, I M

    1994-01-01

    To describe causally predictive relationships, model parameters and the data used to estimate them must correspond to the social context of causal actions. Causes may act directly upon the individual, during a contact between individuals, or upon a group dynamic. Assuming that outcomes in different individuals are independent puts the causal action directly upon individuals. Analyses making this assumption are thus inappropriate for infectious diseases, for which risk factors alter the outcome of contacts between individuals. Transmission during contact generates nonlinear infection dynamics. These dynamics can so attenuate exposure-infection relationships at the individual level that even risk factors causing the vast majority of infections can be missed by individual-level analyses. On the other hand, these dynamics amplify causal associations between exposure and infection at the ecological level. The amplification and attenuation derive from chains of transmission initiated by exposed individuals but involving unexposed individuals. A study of household exposure to the only vector of dengue in Mexico illustrates the phenomenon. An individual-level analysis demonstrated almost no association between exposure and infection. Ecological analysis, in contrast, demonstrated a strong association. Transmission models that are devoid of any sources of the ecological fallacy are used to illustrate how nonlinear dynamics generate such results. PMID:8179058

  11. 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

  12. Disease ecology across soil boundaries: effects of below-ground fungi on above-ground host-parasite interactions.

    PubMed

    Tao, Leiling; Gowler, Camden D; Ahmad, Aamina; Hunter, Mark D; de Roode, Jacobus C

    2015-10-22

    Host-parasite interactions are subject to strong trait-mediated indirect effects from other species. However, it remains unexplored whether such indirect effects may occur across soil boundaries and connect spatially isolated organisms. Here, we demonstrate that, by changing plant (milkweed Asclepias sp.) traits, arbuscular mycorrhizal fungi (AMF) significantly affect interactions between a herbivore (the monarch butterfly Danaus plexippus) and its protozoan parasite (Ophryocystis elektroscirrha), which represents an interaction across four biological kingdoms. In our experiment, AMF affected parasite virulence, host resistance and host tolerance to the parasite. These effects were dependent on both the density of AMF and the identity of milkweed species: AMF indirectly increased disease in monarchs reared on some species, while alleviating disease in monarchs reared on other species. The species-specificity was driven largely by the effects of AMF on both plant primary (phosphorus) and secondary (cardenolides; toxins in milkweeds) traits. Our study demonstrates that trait-mediated indirect effects in disease ecology are extensive, such that below-ground interactions between AMF and plant roots can alter host-parasite interactions above ground. In general, soil biota may play an underappreciated role in the ecology of many terrestrial host-parasite systems. PMID:26468247

  13. 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 productionthe most widespread and long-running commercial use of public landscan 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.

  14. Effect of Classification Procedure on the Performance of Numerically Defined Ecological Regions

    NASA Astrophysics Data System (ADS)

    Snelder, Ton; Lehmann, Anthony; Lamouroux, Nicolas; Leathwick, John; Allenbach, Karin

    2010-05-01

    Ecological regionalizations define geographic regions exhibiting relative homogeneity in ecological (i.e., environmental and biotic) characteristics. Multivariate clustering methods have been used to define ecological regions based on subjectively chosen environmental variables. We developed and tested three procedures for defining ecological regions based on spatial modeling of a multivariate target pattern that is represented by compositional dissimilarities between locations (e.g., taxonomic dissimilarities). The procedures use a “training dataset” representing the target pattern and models this as a function of environmental variables. The model is then extrapolated to the entire domain of interest. Environmental data for our analysis were drawn from a 400 m grid covering all of Switzerland and consisted of 12 variables describing climate, topography and lithology. Our target patterns comprised land cover composition of each grid cell that was derived from interpretation of aerial photographs. For Regionalization 1 we used conventional cluster analysis of the environmental variables to define 60 hierarchically organized levels comprising from 5 to 300 regions. Regionalization 1 provided a base-case for comparison with the model-based regionalizations. Regionalization 2, 3 and 4 also comprised 60 hierarchically organized levels and were derived by modeling land cover composition for 4000 randomly selected “training” cells. Regionalization 2 was based on cluster analysis of environmental variables that were transformed based on a Generalized Dissimilarity Model (GDM). Regionalization 3 and 4 were defined by clustering the training cells based on their land cover composition followed by predictive modeling of the distribution of the land cover clusters using Classification and Regression Tree (CART) and Random Forest (RF) models. Independent test data (i.e. not used to train the models) were used to test the discrimination of land cover composition at all hierarchical levels of the regionalizations using the classification strength ( CS) statistic . CS for all the model-based regionalizations was significantly higher than for Regionalization 1. Regionalization 3 and 4 performed significantly better than Regionalization 2 at finer hierarchical levels (many regions) and Regionalization 4 performed significantly better than Regionalization 3 for coarse levels of detail (few regions). Compositional modeling can significantly increase the performance of numerically defined ecological regionalizations. CART and RF-based models appear to produce stronger regionalizations because discriminating variables are able to change at each hierarchic level.

  15. Effect of classification procedure on the performance of numerically defined ecological regions.

    PubMed

    Snelder, Ton; Lehmann, Anthony; Lamouroux, Nicolas; Leathwick, John; Allenbach, Karin

    2010-05-01

    Ecological regionalizations define geographic regions exhibiting relative homogeneity in ecological (i.e., environmental and biotic) characteristics. Multivariate clustering methods have been used to define ecological regions based on subjectively chosen environmental variables. We developed and tested three procedures for defining ecological regions based on spatial modeling of a multivariate target pattern that is represented by compositional dissimilarities between locations (e.g., taxonomic dissimilarities). The procedures use a "training dataset" representing the target pattern and models this as a function of environmental variables. The model is then extrapolated to the entire domain of interest. Environmental data for our analysis were drawn from a 400 m grid covering all of Switzerland and consisted of 12 variables describing climate, topography and lithology. Our target patterns comprised land cover composition of each grid cell that was derived from interpretation of aerial photographs. For Regionalization 1 we used conventional cluster analysis of the environmental variables to define 60 hierarchically organized levels comprising from 5 to 300 regions. Regionalization 1 provided a base-case for comparison with the model-based regionalizations. Regionalization 2, 3 and 4 also comprised 60 hierarchically organized levels and were derived by modeling land cover composition for 4000 randomly selected "training" cells. Regionalization 2 was based on cluster analysis of environmental variables that were transformed based on a Generalized Dissimilarity Model (GDM). Regionalization 3 and 4 were defined by clustering the training cells based on their land cover composition followed by predictive modeling of the distribution of the land cover clusters using Classification and Regression Tree (CART) and Random Forest (RF) models. Independent test data (i.e. not used to train the models) were used to test the discrimination of land cover composition at all hierarchical levels of the regionalizations using the classification strength (CS) statistic. CS for all the model-based regionalizations was significantly higher than for Regionalization 1. Regionalization 3 and 4 performed significantly better than Regionalization 2 at finer hierarchical levels (many regions) and Regionalization 4 performed significantly better than Regionalization 3 for coarse levels of detail (few regions). Compositional modeling can significantly increase the performance of numerically defined ecological regionalizations. CART and RF-based models appear to produce stronger regionalizations because discriminating variables are able to change at each hierarchic level. PMID:20300935

  16. 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.

  17. Application of microcosmic system for assessment of insecticide effects on biomarker responses in ecologically different earthworm species.

    PubMed

    Velki, Mirna; Hackenberger, Branimir K; Lončarić, 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

  18. 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.

  19. The road to rack and ruin: selecting deleterious mitochondrial DNA variants

    PubMed Central

    Holt, Ian J.; Speijer, Dave; Kirkwood, Thomas B. L.

    2014-01-01

    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

  20. Iron transport-mediated antagonism between plant growth-promoting and plant-deleterious Pseudomonas strains.

    PubMed

    Buyer, J S; Leong, J

    1986-01-15

    Both plant growth-promoting Pseudomonas B10 and its yellow-green, fluorescent iron transport agent (siderophore) pseudobactin enhance potato growth and biologically control certain soil-borne fungal diseases in part by depriving specific root-colonizing endemic microorganisms including phytopathogens of iron(III), thus inhibiting their growth. The present study examines this mode of iron deprivation. The growth inhibition of certain bean-deleterious fluorescent pseudomonads by specific bean-beneficial fluorescent pseudomonads is due in part to the inability of susceptible strains to utilize siderophores from beneficial strains to transport iron(III). Conversely, deleterious strains which were able to utilize siderophores from beneficial strains were not inhibited. The ability of a given pseudomonad to utilize another pseudomonad's siderophore may depend upon its possessing a specific outer membrane receptor protein for that pseudomonad's ferric siderophore. Siderophore-mediated competition for iron in microbial systems appears to be a widespread phenomenon. PMID:2934391

  1. Ringed-seal winter ecology and effects of noise disturbance. Final report

    SciTech Connect

    Kelly, B.P.; Quakenbush, L.T.; Rose, J.R.

    1986-12-01

    The ecological importance of lair use and the responses of individual ringed seals to noise disturbance were studied telemetrically over three years. The objectives were: to determine the number of subnivean lairs utilized by individual ringed seals and the spatial distribution of those lairs; to determine the patterns of daily and seasonal use of subnivean lairs by ringed seals; to determine the thermal advantage realized by ringed seals occupying subnivean lairs; and to determine how lair occupancy is affected by noise disturbances, including seismic exploration.

  2. An ecological approach to learning with technology: responding to tensions within the "wow-effect" phenomenon in teaching practices

    NASA Astrophysics Data System (ADS)

    Herro, Danielle

    2016-02-01

    This review explores Anne Kamstrupp's "The Wow-effect in Science Teacher Education" by examining her theorized "wow-effect" as a teaching enactment that may serve to engage students, but often fails to provide deep understanding of science content. My response extends her perspective of socio-materiality as means to understand the "wow-effect" by suggesting social constructivism provides a more accurate lens to disentangle the phenomenon. I react to her position that tension fields within the phenomenon include the relationship between new and old technologies, boredom and engagement, and active and sedentary learning. In this conversation, I point to a new way of conceptualizing using digital media in the classroom as ecology of learning that may serve to decrease problems associated with the "wow-effect".

  3. 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.

  4. Extrapolation of available acute and chronic toxicity test data to population-level effects for ecological risk management of chemicals.

    PubMed

    Lin, Bin-Le; Meng, Yaobin

    2009-07-01

    An extrapolation approach is proposed using available acute (median lethal or effect concentration) and chronic (no-observed-effect concentration) toxicity test data at the organism level to derive a reference value contributing to the development of predicted-no-effect concentration on population persistence for population-level ecological risk assessment of chemicals. A matrix population model of wild medaka (Oryzias latipes) was employed as the tool to integrate the available organism-level toxicity test data on reproduction and survival into a finite population growth rate (lambda) that provides information regarding the status of the population persistence. After demonstrating the approach using the acute and chronic toxicity test data of alcohol ethyxolate on fish to calculate the reference value defined as the concentration at lambda = 1 (C(lambda=1)), the proposed approach was then evaluated by a comparison of the C(lambda=1) value derived by the extrapolation approach to those C(lambda=1) values calculated by two other approaches, in which different amounts of toxicity information contained in the same full life-cycle toxicity test data set on 4-nonylphenol were employed. It was concluded that this extrapolation approach is widely applicable and is promising for performing population-level ecological risk assessment on a more general basis that can support reasonable chemical management. PMID:19239318

  5. 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

  6. Ecological Distribution of Indicator Species and Effective Edaphical Factors on the Northern Iran Lowland Forests

    NASA Astrophysics Data System (ADS)

    Kooch, Y.; Bahmanyar, H. Jalilvand M. A.; Pormajidian, M. R.

    The objectives of this research were to identify the ecological species groups and study the relationship between topographic and edaphic factors with plant species to determine the main factors affecting the separation of vegetation types in Khanikan lowland forests of Mazandaran province (North of Iran). Vegetation was sampled with randomized-systematic method. Vegetation data including density and cover percentage were estimated quantitatively within each quadrate and using the two-way indicator species analysis (TWINSPAN). Vegetation was classified into different groups. The topographic conditions were recorded in quadrate locations. Soil samples were taken from organic horizon (litter layer) and mineral layers (0-10, 10-20 and 20-30 cm). Soil acidity, bulk density, saturation moisture, electrical conductivity, organic carbon, total nitrogen, cation exchangeable capacity, available phosphorous, soil texture, lime, biomass of earthworms, litter carbon and litter nitrogen were measured. Multivariate techniques were used to analyze the collected data. The results indicated that the vegetation distribution patters were mainly related to soil characteristics such as pH, bulk density, texture, phosphorous, organic carbon, nitrogen and CEC. Totally, considering the habitat conditions and ecological needs, each plant species has a significant relation with soil properties.

  7. 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

  8. Ecological restoration and effect investigation of a river wetland in a semi-arid region, China

    NASA Astrophysics Data System (ADS)

    Xu, S.; Jiang, X.; Liu, Y.; Fu, Y.; Zhao, Q.

    2015-05-01

    River wetlands are heavily impacted by human intervention. The degradation and loss of river wetlands has made the restoration of river ecosystems a top priority. How to rehabilitate rivers and their services has been a research focus. The main goal of it is to restore the river wetland ecosystems with ecological methods. The Gudong River was selected as a study site in Chaoyang city in this study. Based on the analysis of interference factors in the river wetland degradation, a set of restoration techniques were proposed and designed for regional water level control, including submerged dikes, ecological embankments, revegetation and dredging. The restoration engineering has produced good results in water quality, eco-environment, and landscape. Monthly reports of the Daling River show that the water quality of Gudong River was better than Grade III in April 2013 compared with Grade V in May 2012. The economic benefit after restoration construction is 1.71 million RMB per year, about 1.89 times that before. The ratio of economic value, social value and eco-environmental value is 1:4:23.

  9. 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.

  10. 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.

  11. 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

  12. Ecology has contrasting effects on genetic variation within species versus rates of molecular evolution across species in water beetles

    PubMed Central

    Fujisawa, Tomochika; Vogler, Alfried P.; Barraclough, Timothy G.

    2015-01-01

    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

  13. Effectiveness of birds, butterflies, dragonflies, damselflies and invertebrates as indicators of freshwater ecological integrity

    NASA Astrophysics Data System (ADS)

    Chama, Lackson; Siachoono, Stanford

    2015-04-01

    Human activities such as mining and agriculture are among the major threats to biodiversity globally. Discharges from these activities have been shown to negatively affect ecological processes, leading to ecosystem degradation and species loss across biomes. Freshwater systems have been shown to be particularly vulnerable, as discharges tend to spread rapidly here than in other ecosystems. Hence, there is need to routinely monitor the quality of these systems if impacts of discharges from human activities are to be minimised. Besides the use of conventional laboratory techniques, several studies have recently shown that organisms such as birds, butterflies, dragonflies, damselflies and invertebrates are also good indicators of ecological integrity and should therefore be used as alternatives to monitoring the quality of various ecosystems. However, most of these studies have only studied one or two of these organisms against ecosystem health, and it remains unclear whether all of them respond similarly to changes in different drivers of environmental change. We investigated the response of the diversity of birds, butterflies, dragonflies, damselflies and invertebrates to changing water quality along the Kafue River in Zambia. Sampling was done at 13 different sampling points stretching over a distance of 60Km along the river. At each point, both the diversity of each organism and the water quality were assessed. Water quality was determined by testing its temperature, pH, redox, electrical conductivity, turbidity and copper parameters. We then tested how the diversity of each organism responded to changes in these water parameters. All water parameters varied significantly across sampling points. The diversity of birds and damselflies remained unaffected by any of the water parameters used. However, the diversity of butterflies reduced with increasing pH, turbidity and copper, albeit it remained unaffected by other water parameters. The diversity of dragonflies reduced with increasing redox, electrical conductivity and turbidity, but remained unaffected by other water parameters. The diversity of invertebrates reduced with increasing redox and copper, but remained unaffected by other water parameters. Generally, these results suggest that these organisms, especially butterflies, dragonflies and invertebrates can indeed be used as indicators of changing water quality and ecological integrity in particular. However, their use is limited to specific, rather than, all water parameters. Therefore, the decision as to which organisms to use should largely depend on which water quality parameters are to be tested. Key words: temperature; pH; redox; electrical conductivity; turbidity; copper

  14. 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...

  15. Targeted Deep Sequencing in Multiple-Affected Sibships of European Ancestry Identifies Rare Deleterious Variants in PTPN22 That Confer Risk for Type 1 Diabetes.

    PubMed

    Ge, Yan; Onengut-Gumuscu, Suna; Quinlan, Aaron R; Mackey, Aaron J; Wright, Jocyndra A; Buckner, Jane H; Habib, Tania; Rich, Stephen S; Concannon, Patrick

    2016-03-01

    Despite finding more than 40 risk loci for type 1 diabetes (T1D), the causative variants and genes remain largely unknown. Here, we sought to identify rare deleterious variants of moderate-to-large effects contributing to T1D. We deeply sequenced 301 protein-coding genes located in 49 previously reported T1D risk loci in 70 T1D cases of European ancestry. These cases were selected from putatively high-risk families that had three or more siblings diagnosed with T1D at early ages. A cluster of rare deleterious variants in PTPN22 was identified, including two novel frameshift mutations (ss538819444 and rs371865329) and two missense variants (rs74163663 and rs56048322). Genotyping in 3,609 T1D families showed that rs56048322 was significantly associated with T1D and that this association was independent of the T1D-associated common variant rs2476601. The risk allele at rs56048322 affects splicing of PTPN22, resulting in the production of two alternative PTPN22 transcripts and a novel isoform of LYP (the protein encoded by PTPN22). This isoform competes with the wild-type LYP for binding to CSK and results in hyporesponsiveness of CD4(+) T cells to antigen stimulation in T1D subjects. These findings demonstrate that in addition to common variants, rare deleterious variants in PTPN22 exist and can affect T1D risk. PMID:26631741

  16. An ecological study for Sri Lanka about health effects of coconut.

    PubMed

    Athauda, L K; Wickremasinghe, A R; Kumarendran, B; Kasturiratne, A

    2015-09-01

    An ecological correlation study was conducted to determine the association between consumption of coconut products and cardiovascular disease (CVD) deaths in Sri Lanka. Data on coconut consumption patterns from 1961 to 2006 were abstracted from the FAO database, and mortality data from reports of the Department of Census and Statistics, and UN databases. Correlational and regression analyses were carried out. There was no increase in the per capita consumption of coconut products from 1961 to 2006 (range 54.1-76.2kg/ capita/year). The CVD death rates and the proportionate mortality rate due to CVD increased from 1961 to 2006. CVD death rates were significantly associated with per capita GDP, percentage of urban population, and elderly dependency ratio but not consumption of coconut products after adjusting for the other variables (R2=0.94). The results do not provide evidence at the population level that consumption of coconut products increases mortality due to cardiovascular diseases. PMID:26520863

  17. Disease effects on lobster fisheries, ecology, and culture: overview of DAO Special 6.

    PubMed

    Behringer, Donald C; Butler, Mark J; Stentiford, Grant D

    2012-08-27

    Lobsters are prized by commercial and recreational fishermen worldwide, and their populations are therefore buffeted by fishery practices. But lobsters also remain integral members of their benthic communities where predator-prey relationships, competitive interactions, and host-pathogen dynamics push and pull at their population dynamics. Although lobsters have few reported pathogens and parasites relative to other decapod crustaceans, the rise of diseases with consequences for lobster fisheries and aquaculture has spotlighted the importance of disease for lobster biology, population dynamics and ecology. Researchers, managers, and fishers thus increasingly recognize the need to understand lobster pathogens and parasites so they can be managed proactively and their impacts minimized where possible. At the 2011 International Conference and Workshop on Lobster Biology and Management a special session on lobster diseases was convened and this special issue of Diseases of Aquatic Organisms highlights those proceedings with a suite of articles focused on diseases discussed during that session. PMID:23186696

  18. [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

  19. Use of marine fouling communities to evaluate the ecological effects of pollution. Final report

    SciTech Connect

    Johnston, R.K.

    1990-06-01

    The ecological consequences of pollution were evaluated by measuring the biological responses of marine fouling communities to increasing levels of pollution in San Diego Bay, California. Measurements of a gradient of increasing levels of copper and organotin compounds were made using anodic stripping voltammetry and inductively coupled plasma spectroscopy for copper and hydride derivation with atomic spectroscopy detection for the organotin compounds tributyltin (TBT), dibutyltin, and monobutyltin. The copper gradient increased by a factor of 4.2 and the TBT gradient increased by a factor of 8.75. Differences in community structures were correlated with distinctly higher concentrations of toxic chemicals present at locations along the gradient. A portable microcosm system was used to study the community responses to different concentrations of TBT in controlled environments. The microcosm study was inconclusive because there was very low settlement of fouling organisms in the microcosm tanks relative to their settlement and colonization in the bay.

  20. Effect of temporal and spatial variability on the classification of the Ecological Quality Status using the CARLIT Index.

    PubMed

    Cavallo, Marianna; Torras, Xavier; Mascaró, Oriol; Ballesteros, Enric

    2016-01-15

    Methodologies developed by European Member States to assess the environmental quality of their coastal waters under the EU Water Framework Directive (WFD, 2000/60/EC) may have an associated source of uncertainty. Here we identify and quantify the level of uncertainty in the CARLIT (Cartography of littoral and upper-sublittoral communities) methodology to test its effectiveness and reliability. The outcomes show that the effect of temporal variability (among years) within each water body is low when CARLIT is performed every year along the entire rocky coast. The spatial variability within a water body is also low. According to these results, CARLIT could be performed every 3years across all the water body or, alternatively, every year considering at least 60% of each water body, without a significant reduction of the confidence in the classification of the Ecological Quality Status (EQS). PMID:26639652

  1. Studying the Confounding Effects of Socio-Ecological Conditions in Retrospective Clinical Research: A Use Case of Social Stress

    PubMed Central

    Breitenstein, Matthew K.; Pathak, Jyotishman; Simon, Gyorgy

    2015-01-01

    Socio-ecological Conditions (SECs) are important to include in clinical research models as they have been known to impact the health of patients. However, current clinical research models account for these factors only in an unsatisfyingly rudimentary way. In this study, we developed an SEC Index that captured the latent and direct effects of social stress, one of the many kinds of SEC, on patients general health as measured by the Charlson Comorbidity Index. We demonstrated that the above SEC Index had a significant effect in a clinical model, a patient-level model with the specific clinical outcome of breast cancer prevalence. Further, we demonstrated that including the SEC Index of social stress into the clinical models significantly increased their performance. Our study demonstrated a viable approach that is interchangeable to include any SEC of interest, to more appropriately account for SECs in clinical research models. PMID:26306230

  2. 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.

  3. Sediment-phosphorus dynamics can shift aquatic ecology and cause downstream legacy effects after wildfire in large river systems.

    PubMed

    Emelko, Monica B; Stone, Micheal; Silins, Uldis; Allin, Don; Collins, Adrian L; Williams, Chris H S; Martens, Amanda M; Bladon, Kevin D

    2016-03-01

    Global increases in the occurrence of large, severe wildfires in forested watersheds threaten drinking water supplies and aquatic ecology. Wildfire effects on water quality, particularly nutrient levels and forms, can be significant. The longevity and downstream propagation of these effects as well as the geochemical mechanisms regulating them remain largely undocumented at larger river basin scales. Here, phosphorus (P) speciation and sorption behavior of suspended sediment were examined in two river basins impacted by a severe wildfire in southern Alberta, Canada. Fine-grained suspended sediments (<125 μm) were sampled continuously during ice-free conditions over a two-year period (2009-2010), 6 and 7 years after the wildfire. Suspended sediment samples were collected from upstream reference (unburned) river reaches, multiple tributaries within the burned areas, and from reaches downstream of the burned areas, in the Crowsnest and Castle River basins. Total particulate phosphorus (TPP) and particulate phosphorus forms (nonapatite inorganic P, apatite P, organic P), and the equilibrium phosphorus concentration (EPC0 ) of suspended sediment were assessed. Concentrations of TPP and the EPC0 were significantly higher downstream of wildfire-impacted areas compared to reference (unburned) upstream river reaches. Sediments from the burned tributary inputs contained higher levels of bioavailable particulate P (NAIP) - these effects were also observed downstream at larger river basin scales. The release of bioavailable P from postfire, P-enriched fine sediment is a key mechanism causing these effects in gravel-bed rivers at larger basin scales. Wildfire-associated increases in NAIP and the EPC0 persisted 6 and 7 years after wildfire. Accordingly, this work demonstrated that fine sediment in gravel-bed rivers is a significant, long-term source of in-stream bioavailable P that contributes to a legacy of wildfire impacts on downstream water quality, aquatic ecology, and drinking water treatability. PMID:26313547

  4. 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 (β = 0.03, 95% CI = −1.2–1.3) or nest survival (β = −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 (β = -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

  5. 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/

  6. Ecological niche

    SciTech Connect

    Shugart, H.H.

    1980-01-01

    The ecological niche of an organism is the set of environmental conditions under which the particular functions of the organism could be expected to assure its survival. It comprises both the set of conditions where the organism lives (often termed the habitat of the organism) and the functional role of the organism in the ecosystem. Recent works in niche theory have enabled ecologists to develop predictions and actual applications. The history of the niche concept, applications of niche theory, and ecological differences between similar species are discussed.

  7. 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

  8. 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

  9. Effective coordination and cooperation between ecological risk assessments and natural resource damage assessments: a new synthesis.

    PubMed

    Gouguet, Ronald G; Charters, David W; Champagne, Larry F; Davis, Mark; Desvouges, William; Durda, Judi L; Hyatt, William H; Jacobson, Rachel; Kapustka, Larry; Longoria, Rose M

    2009-10-01

    Although ecological risk assessments (ERAs) and natural resource damage assessments (NRDAs) are performed under different statutory and regulatory authorities, primarily the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), as currently practiced, the activities typically overlap. ERAs performed as part of the response process (typically by the US Environmental Protection Agency [USEPA]) should be closely coordinated with the natural resource trustees' (trustees') NRDAs. Trustees should actively participate in the early stages of the remedial investigation (RI) and work with USEPA, including the potentially responsible parties (PRPs), when appropriate, to coordinate NRDA data needs with those of the RI. Close coordination can present opportunities to avoid inefficiencies, such as unnecessary resampling or duplicate data gathering, and provide the opportunity to fulfill both process requirements with a few well-designed investigations. Early identification of opportunities for practical combined assessment can save money and time as the restoration process proceeds and facilitate a cooperative resolution of the entire site's CERCLA liability. The Society of Environmental Toxicology and Chemistry (SETAC) convened an invited workshop (August 2008) to address coordination between ERA and NRDA efforts. This paper presents the findings and conclusions of the Framework Work Group, which considered technical issues common to each process, while mindful of the current legal and policy landscape, and developed recommendations for future practice. PMID:19545190

  10. Effect of infrastructure design on commons dilemmas in social-ecological system dynamics.

    PubMed

    Yu, David J; Qubbaj, Murad R; Muneepeerakul, Rachata; Anderies, John M; Aggarwal, Rimjhim M

    2015-10-27

    The use of shared infrastructure to direct natural processes for the benefit of humans has been a central feature of human social organization for millennia. Today, more than ever, people interact with one another and the environment through shared human-made infrastructure (the Internet, transportation, the energy grid, etc.). However, there has been relatively little work on how the design characteristics of shared infrastructure affect the dynamics of social-ecological systems (SESs) and the capacity of groups to solve social dilemmas associated with its provision. Developing such understanding is especially important in the context of global change where design criteria must consider how specific aspects of infrastructure affect the capacity of SESs to maintain vital functions in the face of shocks. Using small-scale irrigated agriculture (the most ancient and ubiquitous example of public infrastructure systems) as a model system, we show that two design features related to scale and the structure of benefit flows can induce fundamental changes in qualitative behavior, i.e., regime shifts. By relating the required maintenance threshold (a design feature related to infrastructure scale) to the incentives facing users under different regimes, our work also provides some general guidance on determinants of robustness of SESs under globalization-related stresses. PMID:26460043

  11. Ecological consequences of the bold-shy continuum: the effect of predator boldness on prey risk.

    PubMed

    Ioannou, C C; Payne, M; Krause, J

    2008-08-01

    Although the existence of different personality traits within and between animal populations has been relatively well established, the ecological implications of this variation remain neglected. In this study we tested whether differences in the boldness of pairs of three-spined sticklebacks led to differential predation risk in their prey, Chironomidae larvae. Bolder pairs, those that left a refuge and crossed the tank mid-line sooner, ate a greater proportion of prey in 10 min than less bold fish (therefore prey were at a greater per capita risk). Fish crossed the mid-line more rapidly when a larger number of prey were presented, suggesting they accepted greater risk in return for a larger foraging reward. Perception of predation risk also affected the differences between fish in boldness, as larger fish crossed the mid-line sooner after leaving the refuge (larger fish are less at risk from predation). Hence, an interesting trophic interaction occurs, where the risk experienced by the chironomid larvae is determined by the risk perceived by their predators. Through the variation generated by boldness, a form of behaviourally mediated trophic cascade can occur within (as well as between) communities. PMID:18481092

  12. 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 (β = 0.03, 95% CI = -1.2-1.3) or nest survival (β = -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

  13. Aspen Ecology in Rocky Mountain National Park: Age Distribution, Genetics, and the Effects of Elk Herbivory

    SciTech Connect

    Tuskan, Gerald A; Yin, Tongming

    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.

  14. 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).

  15. Defending Ecology.

    ERIC Educational Resources Information Center

    Margolis, Brian

    2000-01-01

    Explains how non-native species' problems in the ecosystem can introduce fundamental ecological principles in the classroom. Provides background information on damages caused by non-native species. Discusses how educators can use this environmental issue in the classroom and gives the example of zebra mussels. Lists instructional strategies for…

  16. Trash Ecology

    ERIC Educational Resources Information Center

    Lind, Georgia J.

    2004-01-01

    A hands on activity involving density, frequency and biomass using transects, quadrats and a local good deed by cleaning up the neighborhood while practicing important techniques in ecology is detailed. The activity is designed for KCC-STEP, whose primary goal is to expand the scientific knowledge and research experiences of their students, who…

  17. Trash Ecology

    ERIC Educational Resources Information Center

    Lind, Georgia J.

    2004-01-01

    A hands on activity involving density, frequency and biomass using transects, quadrats and a local good deed by cleaning up the neighborhood while practicing important techniques in ecology is detailed. The activity is designed for KCC-STEP, whose primary goal is to expand the scientific knowledge and research experiences of their students, who

  18. Defending Ecology.

    ERIC Educational Resources Information Center

    Margolis, Brian

    2000-01-01

    Explains how non-native species' problems in the ecosystem can introduce fundamental ecological principles in the classroom. Provides background information on damages caused by non-native species. Discusses how educators can use this environmental issue in the classroom and gives the example of zebra mussels. Lists instructional strategies for

  19. Inferring time-variable effects of nutrient enrichment on marine ecosystems using inverse modelling and ecological network analysis.

    PubMed

    Luong, Anh D; De Laender, Frederik; Olsen, Yngvar; Vadstein, Olav; Dewulf, Jo; Janssen, Colin R

    2014-09-15

    We combined data from an outdoor mesocosm experiment with carbon budget modelling and an ecological network analysis to assess the effects of continuous nutrient additions on the structural and functional dynamics of a marine planktonic ecosystem. The food web receiving no nutrient additions was fuelled by detritus, as zooplankton consumed 7.2 times more detritus than they consumed algae. Nutrient supply instantly promoted herbivory so that it was comparable to detritivory at the highest nutrient addition rate. Nutrient-induced food web restructuring reduced carbon cycling and decreased the average number of compartments a unit flow of carbon crosses before dissipation. Also, the efficiency of copepod production, the link to higher trophic levels harvestable by man, was lowered up to 35 times by nutrient addition, but showed signs of recovery after 9 to 11 days. The dependency of the food web on exogenous input was not changed by the nutrient additions. PMID:24992463

  20. Environmental Variables Shaping the Ecological Niche of Thaumarchaeota in Soil: Direct and Indirect Causal Effects

    PubMed Central

    Hong, Jin-Kyung; Cho, Jae-Chang

    2015-01-01

    To find environmental variables (EVs) shaping the ecological niche of the archaeal phylum Thaumarchaeota in terrestrial environments, we determined the abundance of Thaumarchaeota in various soil samples using real-time PCR targeting thaumarchaeotal 16S rRNA gene sequences. We employed our previously developed primer, THAUM-494, which had greater coverage for Thaumarchaeota and lower tolerance to nonthaumarchaeotal taxa than previous Thaumarchaeota-directed primers. The relative abundance estimates (RVs) of Thaumarchaeota (RTHAUM), Archaea (RARCH), and Bacteria (RBACT) were subjected to a series of statistical analyses. Redundancy analysis (RDA) showed a significant (p < 0.05) canonical relationship between RVs and EVs. Negative causal relationships between RTHAUM and nutrient level–related EVs were observed in an RDA biplot. These negative relationships were further confirmed by correlation and regression analyses. Total nitrogen content (TN) appeared to be the EV that affected RTHAUM most strongly, and total carbon content (TC), which reflected the content of organic matter (OM), appeared to be the EV that affected it least. However, in the path analysis, a path model indicated that TN might be a mediator EV that could be controlled directly by the OM. Additionally, another path model implied that water content (WC) might also indirectly affect RTHAUM by controlling ammonium nitrogen (NH4+-N) level through ammonification. Thus, although most directly affected by NH4+-N, RTHAUM could be ultimately determined by OM content, suggesting that Thaumarchaeota could prefer low-OM or low-WC conditions, because either of these EVs could subsequently result in low levels of NH4+-N in soil. PMID:26241328

  1. Deleterious Germline BLM Mutations and the Risk for Early-onset Colorectal Cancer

    PubMed Central

    de Voer, Richarda M.; Hahn, Marc-Manuel; Mensenkamp, Arjen R.; Hoischen, Alexander; Gilissen, Christian; Henkes, Arjen; Spruijt, Liesbeth; van Zelst-Stams, Wendy A.; Marleen Kets, C.; Verwiel, Eugene T.; Nagtegaal, Iris D.; Schackert, Hans K.; van Kessel, Ad Geurts; Hoogerbrugge, Nicoline; Ligtenberg, Marjolijn J.L.; Kuiper, Roland P.

    2015-01-01

    Bloom syndrome is an autosomal recessive disorder characterized by chromosomal instability and increased cancer risk, caused by biallelic mutations in the RECQL-helicase gene BLM. Previous studies have led to conflicting conclusions as to whether carriers of heterozygous BLM mutations have an increased risk to develop colorectal cancer (CRC). We recently identified two carriers of a pathogenic BLM mutation in a cohort of 55 early-onset CRC patients (?45 years of age), suggesting an overrepresentation compared to the normal population. Here, we performed targeted sequencing using molecular inversion probes to screen an additional cohort of 185 CRC patients (?50 years of age) and 532 population-matched controls for deleterious BLM mutations. In total, we identified three additional CRC patients (1.6%) and one control individual (0.2%) that carried a known pathogenic BLM mutation, suggesting that these mutations are enriched in early-onset CRC patients (P?=?0.05516). A comparison with local and publically available databases from individuals without suspicion for hereditary cancer confirmed this enrichment (P?=?0.003534). Analysis of family members of the five BLM mutation carriers with CRC suggests an incomplete penetrance for CRC development. Therefore, these data indicate that carriers of deleterious BLM mutations are at increased risk to develop CRC, albeit with a moderate-to-low penetrance. PMID:26358404

  2. In-Silico Computing of the Most Deleterious nsSNPs in HBA1 Gene

    PubMed Central

    AbdulAzeez, Sayed; Borgio, J. Francis

    2016-01-01

    Background ?-Thalassemia (?-thal) is a genetic disorder caused by the substitution of single amino acid or large deletions in the HBA1 and/or HBA2 genes. Method Using modern bioinformatics tools as a systematic in-silico approach to predict the deleterious SNPs in the HBA1 gene and its significant pathogenic impact on the functions and structure of HBA1 protein was predicted. Results and Discussion A total of 389 SNPs in HBA1 were retrieved from dbSNP database, which includes: 201 non-coding synonymous (nsSNPs), 43 human active SNPs, 16 intronic SNPs, 11 mRNA 3? UTR SNPs, 9 coding synonymous SNPs, 9 5? UTR SNPs and other types. Structural homology-based method (PolyPhen) and sequence homology-based tool (SIFT), SNPs&Go, PROVEAN and PANTHER revealed that 2.4% of the nsSNPs are pathogenic. Conclusions A total of 5 nsSNPs (G60V, K17M, K17T, L92F and W15R) were predicted to be responsible for the structural and functional modifications of HBA1 protein. It is evident from the deep comprehensive in-silico analysis that, two nsSNPs such as G60Vand W15R in HBA1 are highly deleterious. These 2 pathogenic nsSNPs can be considered for wet-lab confirmatory analysis. PMID:26824843

  3. Deleterious Germline BLM Mutations and the Risk for Early-onset Colorectal Cancer.

    PubMed

    de Voer, Richarda M; Hahn, Marc-Manuel; Mensenkamp, Arjen R; Hoischen, Alexander; Gilissen, Christian; Henkes, Arjen; Spruijt, Liesbeth; van Zelst-Stams, Wendy A; Kets, C Marleen; Verwiel, Eugene T; Nagtegaal, Iris D; Schackert, Hans K; van Kessel, Ad Geurts; Hoogerbrugge, Nicoline; Ligtenberg, Marjolijn J L; Kuiper, Roland P

    2015-01-01

    Bloom syndrome is an autosomal recessive disorder characterized by chromosomal instability and increased cancer risk, caused by biallelic mutations in the RECQL-helicase gene BLM. Previous studies have led to conflicting conclusions as to whether carriers of heterozygous BLM mutations have an increased risk to develop colorectal cancer (CRC). We recently identified two carriers of a pathogenic BLM mutation in a cohort of 55 early-onset CRC patients (?45 years of age), suggesting an overrepresentation compared to the normal population. Here, we performed targeted sequencing using molecular inversion probes to screen an additional cohort of 185 CRC patients (?50 years of age) and 532 population-matched controls for deleterious BLM mutations. In total, we identified three additional CRC patients (1.6%) and one control individual (0.2%) that carried a known pathogenic BLM mutation, suggesting that these mutations are enriched in early-onset CRC patients (P?=?0.05516). A comparison with local and publically available databases from individuals without suspicion for hereditary cancer confirmed this enrichment (P?=?0.003534). Analysis of family members of the five BLM mutation carriers with CRC suggests an incomplete penetrance for CRC development. Therefore, these data indicate that carriers of deleterious BLM mutations are at increased risk to develop CRC, albeit with a moderate-to-low penetrance. PMID:26358404

  4. 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.

  5. 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.

  6. [Ecological and radio-ecological effects from long-term use of the lake Kyzyl-Tash as a cooling reservoir by the nuclear fuel cycle facility].

    PubMed

    Smagin, A I

    2010-01-01

    This review introduces long-term study findings on ecological and radiation induced regime of the water reservoir - lake Kyzyl-Tash (R-2) - used as a heat sink of nuclear-power reactors in the Southern Urals from 1948 through 2008. It was exhibited that water reservoir exploitation by the nuclear fuel cycle facility "Mayak" PA resulted in hydrological, thermal, hydrochemical and radiological ecosystem regimes changes. The central radioactive substances depot in the water reservoir was determined to be the upper 20-30 cm bed silt layers, contamination density of which in 1980-1990s amounted on average approximately 0.2 PBq/km2 (about 5 kKu/km2). Some regularities of radionuclide distribution in bed sediments and biota were ascertained. Dose estimates from ionizing exposure to fish inhabited the water reservoir were experimentally made. Dose contribution was mainly due to incorporated beta-emitters amounted up to 2-3 Gy/y in 1980s. The leading role in the reservoir life belonged to phytoplankton with its algal nuisance periodicity constituting 5-6 years for blue-green and diatomic algae, and 2-3 years for green algae. During periods of the highest development pressure phytoplankton productive capacity in the reservoir was by an order of magnitude greater compared to control water reservoirs of the region. Combined long-term impact of radiological and chemical factors did not cause irreversible changes either in fish populations or ecological system in general. It can be proved by the fact that during 1970-1980s the water reservoir R-2 was inhabited by such cleanness indicators as crawfish (Astacus leptodactylus) and shellfish (Anodonta cygnea L.). On reducing of thermal and chemical pressure in the end of 1980s some processes observed gave evidence of ecosystem restoration in the lake Kyzyl-Tash. At the present moment the situation of the water reservoir exploiting as a heat sink is stabilized with preserved self-cleaning capacity. PMID:20968056

  7. Evaluation of the Effect of Ecologic on Root Knot Nematode, Meloidogyne incognita, and Tomato Plant, Lycopersicon esculenum

    PubMed Central

    Ladner, Debora C.; Tchounwou, Paul B.; Lawrence, Gary W.

    2008-01-01

    Nonchemical methods and strategies for nematode management including cultural methods and engineered measures have been recommended as an alternative to methyl bromide (a major soil fumigant), due to its role in the depletion of the ozone layer. Hence, an international agreement has recently been reached calling for its reduced consumption and complete phasing out. This present research evaluates the potential of Ecologic, a biological, marine shell meal chitin material, as a soil amendment management agent for root knot nematode, Meloidogyne incognita, control, and its effect on the growth of Floradel tomato plant, Lycopersicon esculentum. To accomplish this goal, studies were conducted during which, experimental pots were set up in greenhouse environments using sterilized soil inoculated with 5,000 root-knot eggs per 1500 g soil. There were 4 treatments and 5 replications. Treatments were: No chitin; 50 g chitin; 100 g chitin; and 200 g chitin. A two-week wait period following Ecologic amendment preceded Floradel tomato planting to allow breakdown of the chitin material into the soil. Fresh and dry weights of shoot and root materials were taken as growth end-points. A statistically significant difference (p ? 0.05) was obtained with regard to the growth rate of L. esculentum at 100 g chitin treatment compared to the control with no chitin. Mean fresh weights of Floradel tomato were 78.0 22.3g, 81.0 20.3g, 109.0 25.4g and 102.0 33.3g at 0, 50, 100 and 200g chitin, respectively. The analysis of root knot nematode concentrations indicated a substantial effect on reproduction rate associated with chitin amendment. Study results showed a significant decrease in both root knot nematode eggs and juveniles (J2) at 100g and 200g Ecologic chitin levels, however, an increase in nematode concentrations was recorded at the 50g Ecologic chitin level (p ? 0.05). The mean amounts of J2 population, as expressed per 1500cm3 soil, were 49,933 38,819, 86,050 25248, 103 133 and 103 133 for 0, 50, 100 and 200g chitin, respectively. Similarly, the mean numbers of root knot nematode eggs (per 1500cm3 of soil) were 40,759 36,712, 66,048 39,730, 9,904 16,591 and 9,257 17,204. Root gall rating was also significantly lower (p ? 0.05) at the 100g and 200g chitin levels compared to the control. Percent gall ratings were 3.3 1.0%, 3.2 1.0%, 1.0 0.5%, and 1.0% 0.6% for amendment levels of 0, 50, 100, and 200g chitin, respectively. PMID:18678924

  8. Effect of dam parity on litter performance, transfer of passive immunity, and progeny microbial ecology.

    PubMed

    Carney-Hinkle, E E; Tran, H; Bundy, J W; Moreno, R; Miller, P S; Burkey, T E

    2013-06-01

    Litter performance and progeny health status may be decreased in progeny derived from primiparous sows but improve with increasing parity. The objective was to evaluate litter performance, the production and passive transfer of Ig, and fecal microbial populations in progeny derived from first parity (P1) compared with fourth parity (P4) dams. Litter performance was recorded for P1 (n = 19) and P4 (n = 24) dams including number of pigs/litter (total born, born live, stillbirths, mummified fetuses, prewean mortality, and pigs weaned) and average litter and piglet BW at birth (d 0), d 7, d 14, and at weaning (average d 19). Blood samples were collected from all dams on d 90 and 114 of gestation and d 0 of lactation. Colostrum and milk samples were collected from each dam on d 0, 7, and 14 of lactation for quantification of IgG and IgA. Blood and fecal samples were collected from each litter (n = 6 pigs/litter) on d 1, 7, and 14 after parturition. Circulating IgG and IgA concentrations were quantified in all blood samples. Denaturing gradient gel electrophoresis (DGGE) was used to characterize similarity and diversity of fecal microbes among progeny. Progeny of P1 dams had decreased average litter BW at d 7 (25.7 vs. 30.0 kg; P < 0.03) and decreased average piglet BW throughout the experiment (d 0, 7, 14, and 19; P < 0.001) compared with P4 progeny. No parity day interactions were observed with respect to immunoglobulin or microbial analyses. Concentrations of IgA tended to be greater (P = 0.09) in samples of colostrum and milk obtained from P4 compared with P1 dams. Serum IgG concentrations were greater (P < 0.02) in P4 progeny compared with P1 progeny. Results of DGGE revealed that P1 progeny had increased (P < 0.001) microbial similarity on d 7 and decreased (P < 0.03) microbial similarity on d 14 compared with P4 progeny. Progeny of P1 dams tended (P = 0.07) to have a greater Shannon's diversity index compared with P4 progeny on d 1, and P1 progeny had a greater (P < 0.03) Shannon's diversity index compared with P4 progeny on d 7. Litter performance, passive transfer of immunity, and progeny microbial ecology were affected by dam parity. PMID:23482585

  9. Will the effects of sea-level rise create ecological traps for Pacific Island seabirds?

    USGS Publications Warehouse

    Reynolds, Michelle H.; Courtot, Karen; Berkowitz, Paul; Storlazzi, Curt; Moore, Janet; Flint, Elizabeth

    2015-01-01

    More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross,Phoebastria immutabilis; black-footed albatross,P.nigripes; and Bonin petrel,Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels.

  10. Effectiveness of post-fire seeding at the Fitzner-Eberhardt Arid Land Ecology Reserve, Washington

    USGS Publications Warehouse

    Wirth, Troy A.; Pyke, David A.

    2011-01-01

    In August 2007, the Milepost 17 and Wautoma fires burned a combined total of 77,349 acres (31,302 hectares) of the Fitzner-Eberhardt Arid Land Ecology Reserve (ALE), part of the Hanford Reach National Monument administered by the U.S. Fish and Wildlife Service (USFWS) Mid-Columbia National Wildlife Refuge. In 2009, the USFWS implemented a series of seeding and herbicide treatments to mitigate potential negative consequences of these fires, including mortality of native vegetation, invasion of Bromus tectorum (cheatgrass), and soil erosion. Treatments included combinations of seeding (drill and aerial), herbicides, and one of six different mixtures of species. Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) also was planted by hand in a small area in the southern end of the fire perimeter. Due to differences in plant communities prior to the fire and the multiple treatments applied, treatments were grouped into five treatment associations including mid-elevation aerial seedings, low-elevation aerial seedings, low-elevation drill seedings, high-elevation drill seeding, and no seeding treatments. Data collected at the mid-elevation aerial seedings indicate that the seeding did not appear to increase the density of seedlings compared to the non-seeded area in 2010. At the low-elevation aerial seedings, there were significantly more seedlings at seeded areas as compared to non-seeded areas. Low densities of existing perennial plants probably fostered a low-competition environment enabling seeds to germinate and emerge in 2010 during adequate moisture. Low-elevation drill seedings resulted in significant emergence of seeded grasses in 2009 and 2010 and forbs in 2010. This was likely due to adequate precipitation and that the drill seeding assured soil-to-seed contact. At the high-elevation drill seeding, which was implemented in 2009, there were a high number of seedlings in 2010. Transplanting of A. tridentata following the fires resulted in variable survival rates that warrant further testing; however, transplants located closer to washes tended to have the highest survival rates. Overall, the low-elevation aerial and drill seedings, and the high-elevation drill seedings resulted in significant numbers of seedlings. Further research is needed on methods that provide land managers with critical information about whether or not to seed post-fire areas including status of pre-fire vegetation and estimates of plant mortality due to fire.

  11. Will the Effects of Sea-Level Rise Create Ecological Traps for Pacific Island Seabirds?

    PubMed Central

    Reynolds, Michelle H.; Courtot, Karen N.; Berkowitz, Paul; Storlazzi, Curt D.; Moore, Janet; Flint, Elizabeth

    2015-01-01

    More than 18 million seabirds nest on 58 Pacific islands protected within vast U.S. Marine National Monuments (1.9 million km2). However, most of these seabird colonies are on low-elevation islands and sea-level rise (SLR) and accompanying high-water perturbations are predicted to escalate with climate change. To understand how SLR may impact protected islands and insular biodiversity, we modeled inundation and wave-driven flooding of a globally important seabird rookery in the subtropical Pacific. We acquired new high-resolution Digital Elevation Models (DEMs) and used the Delft3D wave model and ArcGIS to model wave heights and inundation for a range of SLR scenarios (+0.5, +1.0, +1.5, and +2.0 m) at Midway Atoll. Next, we classified vegetation to delineate habitat exposure to inundation and identified how breeding phenology, colony synchrony, and life history traits affect species-specific sensitivity. We identified 3 of 13 species as highly vulnerable to SLR in the Hawaiian Islands and quantified their atoll-wide distribution (Laysan albatross, Phoebastria immutabilis; black-footed albatross, P. nigripes; and Bonin petrel, Pterodroma hypoleuca). Our models of wave-driven flooding forecast nest losses up to 10% greater than passive inundation models at +1.0 m SLR. At projections of + 2.0 m SLR, approximately 60% of albatross and 44% of Bonin petrel nests were overwashed displacing more than 616,400 breeding albatrosses and petrels. Habitat loss due to passive SLR may decrease the carrying capacity of some islands to support seabird colonies, while sudden high-water events directly reduce survival and reproduction. This is the first study to simulate wave-driven flooding and the combined impacts of SLR, groundwater rise, and storm waves on seabird colonies. Our results highlight the need for early climate change planning and restoration of higher elevation seabird refugia to prevent low-lying protected islands from becoming ecological traps in the face of rising sea levels. PMID:26398209

  12. Functional Molecular Ecological Networks

    PubMed Central

    Zhou, Jizhong; Deng, Ye; Luo, Feng; He, Zhili; Tu, Qichao; Zhi, Xiaoyang

    2010-01-01

    Biodiversity and its responses to environmental changes are central issues in ecology and for society. Almost all microbial biodiversity research focuses on “species” richness and abundance but not on their interactions. Although a network approach is powerful in describing ecological interactions among species, defining the network structure in a microbial community is a great challenge. Also, although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity are well established, its influences on belowground microbial communities, especially microbial interactions, are poorly understood. Here, a random matrix theory (RMT)-based conceptual framework for identifying functional molecular ecological networks was developed with the high-throughput functional gene array hybridization data of soil microbial communities in a long-term grassland FACE (free air, CO2 enrichment) experiment. Our results indicate that RMT is powerful in identifying functional molecular ecological networks in microbial communities. Both functional molecular ecological networks under eCO2 and ambient CO2 (aCO2) possessed the general characteristics of complex systems such as scale free, small world, modular, and hierarchical. However, the topological structures of the functional molecular ecological networks are distinctly different between eCO2 and aCO2, at the levels of the entire communities, individual functional gene categories/groups, and functional genes/sequences, suggesting that eCO2 dramatically altered the network interactions among different microbial functional genes/populations. Such a shift in network structure is also significantly correlated with soil geochemical variables. In short, elucidating network interactions in microbial communities and their responses to environmental changes is fundamentally important for research in microbial ecology, systems microbiology, and global change. PMID:20941329

  13. Direct and indirect effects of light environment generate ecological trade-offs in herbivore performance and parasitism.

    PubMed

    Stoepler, Teresa M; Lill, John T

    2013-10-01

    A variety of ecological factors influence host use by parasitoids, including both abiotic and biotic factors. Light environment is one important abiotic parameter that differs among habitats and influences a suite of plant nutritional and resistance traits that in turn affect herbivore performance. However, the extent to which these bottom-up effects "cascade up" to affect higher trophic levels and the relative importance of direct and indirect effects of sunlight on tritrophic interactions are unclear. The objective of this study was to test how light environment (light gap vs. shaded forest understory) and leaf type (sun vs. shade leaves) affect the performance and incidence of parasitism of two species of moth larvae, Euclea delphinii and Acharia stimulea (Limacodidae). We manipulated the leaf phenotype of potted white oak saplings by growing them in either full sun or full shade throughout leaf expansion to produce sun and shade leaves, respectively. These saplings were then placed in light gap and adjacent shaded understory habitats in the forest in a full-factorial design, and stocked with sentinel larvae that were exposed to parasitism ("exposed" experiments). We reared additional larvae in sleeve cages (protected from parasitism) to isolate light environment and leaf phenotype treatment effects on larval performance in the absence of enemies ("bagged" experiments). In the exposed experiments, light environment strongly affected the likelihood of parasitism, while leaf phenotype did not. Euclea delphinii larvae were up to 6.6 times more likely to be parasitized in light gaps than in shaded understory habitats. This pattern was consistent for both tachinid fly and wasp parasitoids across two separate experiments. However, the larval performance of both species in the bagged experiments was maximized in the shade-habitat/sun-leaf treatment, a habitat/leaf-type combination that occurs infrequently in nature. Taken together, our results suggest that the direct effects of light environment on the incidence of parasitism supersede any indirect effects resulting from altered leaf quality and reveal inherent ecological trade-offs for herbivores confronted with choosing between sunny (high leaf quality, harsh environment, high parasitism) and shaded (reduced leaf quality less harsh environment, reduced parasitism) habitats. PMID:24358715

  14. Effects of dietary supplementation with fermented ginkgo leaves on antioxidant capacity, intestinal morphology and microbial ecology in broiler chicks.

    PubMed

    Zhang, X H; Sun, Z Y; Cao, F L; Ahmad, H; Yang, X H; Zhao, L G; Wang, T

    2015-01-01

    1. The purpose of this study was to evaluate the effects of supplementing diets with three types of fermented Ginkgo-leaves (FGL) on growth, antioxidant capacity, intestinal morphology and microbial ecology in broiler chicks. 2. A total of 300 d-old broilers were randomly allocated to 4 dietary treatments with 6 replications of 10 birds each. Birds were fed on basal diets (Control) or basal diets supplemented with 0.5% FGL with Candida utilis (CF group), Aspergillus niger (AF group) or their combined fermentation (CAF group), respectively, for a 42 d feeding trial. 3. AF and CAF supplementation improved body weight gain (BWG) (22-42 d) and feed conversion ratio (22-42 d and 1-42 d). Concentrations of serum ?-tocopherol in CAF group, as well as hepatic ?-tocopherol in the three FGL groups were increased, while hepatic reactive oxygen species (ROS) levels were greatly decreased in group AF and CAF. Chickens in AF and CAF groups had decreased hepatic protein carbonyls and malondialdehyde (MDA), as well as jejunal and ileal protein carbonyls. The total superoxide dismutase (T-SOD) activities and glutathione (GSH) of both jejunum and ileum of the CAF group were higher than the other groups. 4. Duodenal and jejunal villous height of birds fed on the AF and CAF diets were increased, while jejunal crypt depth (CD) was decreased. Furthermore, birds fed on AF and CAF supplemented diets had increased ileal lactobacilli populations. Decreased ileal and caecal Escherichia coli and Salmonellas populations was found for the birds fed on CAF supplemented diets. 5. The present study may indicate that the improved feed efficiency and intestinal functions in the group supplemented with AF and CAF are directly connected with the improved antioxidant capacity and intestinal microbial ecology. PMID:25868615

  15. 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

  16. [A review on road ecology].

    PubMed

    Li, Yuehui; Hu, Yuanman; Li, Xiuzhen; Xiao, Duning

    2003-03-01

    Roads are a widespread and increasing feature of most landscapes, and have great ecological effects, e.g., increased mortality of animals and plants and habitat loss from road construction, alteration of the physical and chemical environment, and changes in roadsides vegetation. The great impact on animal population includes road-kills, limiting population, road avoidance causing home arrange shift, modification of movement pattern and barrier effect subdividing habitat and populations. Roads alter landscape spatial pattern and interrupt horizontal ecological flows strongly. These impacts can be assayed by indices of road density, road-effect zone and road location. Furthermore, important applications of road ecology to planning, conservation and management are essential and potential. Road ecology presents us a surprising frontier of ecology. PMID:12836559

  17. Ecological Stewardship in Art Education.

    ERIC Educational Resources Information Center

    Lankford, E. Louis

    1997-01-01

    Discusses the philosophical underpinnings and inherent values, actions, and outcomes of accepting and implementing stewardship as a focus for education in art and ecology. Defines three elements of ecological stewardship: moral commitment, understanding the effect of actions, and demonstrating respect. Describes a series of interdisciplinary

  18. Molecular ecology of aquatic microbes

    SciTech Connect

    1994-12-31

    Abstracts of reports are presented from a meeting on Molecular Ecology of Aquatic Microbes. Topics included: opportunities offered to aquatic ecology by molecular biology; the role of aquatic microbes in biogeochemical cycles; characterization of the microbial community; the effect of the environment on aquatic microbes; and the targeting of specific biological processes.

  19. Family Wellness: An Ecological Perspective.

    ERIC Educational Resources Information Center

    Fannin, Ronald A.

    Bronfenbrenner's (1979) concept of human ecology emphasizes the effect of the environment, both physical and psychological, on individual development. Bronfenbrenner's contexts which affect the development of the individual (microsystem, mesosystem, exosystem, macrosystem) can also be defined for the family in an ecological model of family

  20. Weakly Deleterious Mutations and Low Rates of Recombination Limit the Impact of Natural Selection on Bacterial Genomes

    PubMed Central

    Arkin, Adam P.

    2015-01-01

    ABSTRACT Free-living bacteria are usually thought to have large effective population sizes, and so tiny selective differences can drive their evolution. However, because recombination is infrequent, “background selection” against slightly deleterious alleles should reduce the effective population size (Ne) by orders of magnitude. For example, for a well-mixed population with 1012 individuals and a typical level of homologous recombination (r/m = 3, i.e., nucleotide changes due to recombination [r] occur at 3 times the mutation rate [m]), we predict that Ne is <107. An argument for high Ne values for bacteria has been the high genetic diversity within many bacterial “species,” but this diversity may be due to population structure: diversity across subpopulations can be far higher than diversity within a subpopulation, which makes it difficult to estimate Ne correctly. Given an estimate of Ne, standard population genetics models imply that selection should be sufficient to drive evolution if Ne × s is >1, where s is the selection coefficient. We found that this remains approximately correct if background selection is occurring or when population structure is present. Overall, we predict that even for free-living bacteria with enormous populations, natural selection is only a significant force if s is above 10−7 or so. PMID:26670382

  1. Physiological and behavioural effects of imidacloprid on two ecologically relevant earthworm species (Lumbricus terrestris and Aporrectodea caliginosa).

    PubMed

    Dittbrenner, Nils; Triebskorn, Rita; Moser, Isabelle; Capowiez, Yvan

    2010-11-01

    Earthworms play key roles in soils and sub-lethal effects of environmental toxicants on these organisms should be taken seriously, since they might have detrimental effects on higher ecological levels. In laboratory experiments we have assessed sub-lethal effects (body mass change and cast production) of imidacloprid on two earthworm species commonly found in different agricultural soils (Lumbricus terrestris and Aporrectodea caliginosa). After 7 days of exposure in contaminated soil, a significant loss of body mass was found in both species exposed to imidacloprid concentrations as low as 0.66 mg kg(-1) dry soil. These losses ranged from 18.3 to 39% for A. caliginosa and from 7.4 to 32.4% for L. terrestris, respectively. Changes in cast production, a new biomarker previously validated using L. terrestris, was assessed by soil sieving using the recommended mesh size (5.6 mm) for L. terrestris and three different mesh sizes for A. caliginosa (5.6, 4 and 3.15 mm). The 4 mm mesh size proved to be the most suitable sieve size for A. caliginosa. Cast production increased by 26.2% in A. caliginosa and by 28.1% in L. terrestris at the lowest imidacloprid concentration tested (0.2 mg kg(-1) dry soil), but significantly decreased at higher concentrations (equal to and above 0.66 mg kg(-1) dry soil) in both earthworm species after the 7 days exposure experiment. These decreases in cast production ranged from 44.5 to 96.9% in A. caliginosa and from 42.4 to 95.7% in L. terrestris. The EC(50) for cast production were 0.84 (L. terrestris) and 0.76 mg kg(-1) dry soil (A. caliginosa), respectively. The detected sub-lethal effects were found close to the predicted environmental concentration (PEC) of imidacloprid, which is in the range of 0.33-0.66 mg kg(-1) dry soil. The biomarkers used in the present study, body mass change and changes in cast production, may be of ecological relevance and have shown high sensitivity for imidacloprid exposure of earthworms. The measurement of changes in cast production should be considered for inclusion in current standard tests. PMID:20821048

  2. The effect of pro-ecological procedures and insect foraging on the total content of phenol compounds in winter wheat.

    PubMed

    Lamparski, Robert; Balcerek, Maciej; Modnicki, Daniel; Kotwica, Karol; Wawrzyniak, Maria

    2015-06-01

    In laboratory conditions, the effect of pro-ecological procedures (application of effective microorganisms and Asahi SL biostimulator) and foraging by insects [cereal leaf beetle (Oulema melanopa L.) and bird cherry-oat aphid (Rhopalosiphum padi (L.)] on the total content of phenolic compounds in winter wheat, was studied. Correlations between the total content of phenolic compounds (determined by the Folin-Ciocalteau colorimetric method) expressed as the amount of pyrogallol in wheat plants: undamaged, damaged by O. melanopa, damaged by R. padi, the length of feeding scar left by cereal leaf beetle and the number of pricks made by actively feeding insects of bird cherry-oat aphid were analysed. The wheat was treated by EM inoculant and a biostimulator. The mode of application of the preparations used had a significant effect on level the total phenolic compounds in the undamaged wheat and the wheat exposed to foraging by the above-mentioned insects. The plants not exposed to insects foraging contained greater amounts of phenolic compounds than those exposed to the insects. The correlation between the total content of phenols in the wheat damaged by the insects in the 'no-choice' conditions, proved insignificant. PMID:26081273

  3. 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...

  4. The Mozart Effect: Musical Phenomenon or Musical Preference? A More Ecologically Valid Reconsideration

    ERIC Educational Resources Information Center

    Cassity, Hope Daniels; Henley, Tracy B.; Markley, Robert P.

    2007-01-01

    The "Mozart effect" is the reported phenomenon of increased spatial abilities after listening to that composer's music. However, subsequent research suggests that the Mozart effect may be an artifactual consequence of heightened arousal and mood rather than the music of Mozart per se (e.g., Thompson, Schellenberg, & Husain, 2001). The present

  5. The Mozart Effect: Musical Phenomenon or Musical Preference? A More Ecologically Valid Reconsideration

    ERIC Educational Resources Information Center

    Cassity, Hope Daniels; Henley, Tracy B.; Markley, Robert P.

    2007-01-01

    The "Mozart effect" is the reported phenomenon of increased spatial abilities after listening to that composer's music. However, subsequent research suggests that the Mozart effect may be an artifactual consequence of heightened arousal and mood rather than the music of Mozart per se (e.g., Thompson, Schellenberg, & Husain, 2001). The present…

  6. Positive Classroom Ecology.

    ERIC Educational Resources Information Center

    Conoley, Jane Close

    1988-01-01

    Educational environments that reduce the likelihood of acting out and promote positive cognitive, social, and emotional development are useful not only to behavior disordered youngsters, but to all students. Forces that facilitate and inhibit the establishment of positive classroom ecologies are outlined, and components of effective instruction

  7. 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...

  8. Effects of stream topology on ecological community results from neutral models

    EPA Science Inventory