Sample records for deleterious ecological effects

  1. 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)

  2. 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.

  3. 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 ?m. It is shown that depending on the electron energy distribution and the target density profile the hot electrons can either increase the shock amplitude or preheat the imploding shell. In particular, the exponential electron energy spectrum corresponding to the temperature of 30 keV in the present HiPER target design preheats the deuterium-tritium shell and jeopardizes its compression. Ways of improving the target performance are suggested. PMID:24730956

  4. 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...

  5. 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.

  6. Fitness effects of derived deleterious mutations in four closely related wild tomato species with spatial structure

    PubMed Central

    Tellier, A; Fischer, I; Merino, C; Xia, H; Camus-Kulandaivelu, L; Städler, T; Stephan, W

    2011-01-01

    A key issue in evolutionary biology is an improved understanding of the genetic mechanisms by which species adapt to various environments. Using DNA sequence data, it is possible to quantify the number of adaptive and deleterious mutations, and the distribution of fitness effects of new mutations (its mean and variance) by simultaneously taking into account the demography of a given species. We investigated how selection functions at eight housekeeping genes of four closely related, outcrossing species of wild tomatoes that are native to diverse environments in western South America (Solanum arcanum, S. chilense, S. habrochaites and S. peruvianum). We found little evidence for adaptive mutations but pervasive evidence for strong purifying selection in coding regions of the four species. In contrast, the strength of purifying selection seems to vary among the four species in non-coding (NC) regions (introns). Using FST-based measures of fixation in subdivided populations, we suggest that weak purifying selection has affected the NC regions of S. habrochaites, S. chilense and S. peruvianum. In contrast, NC regions in S. arcanum show a distribution of fitness effects with mutations being either nearly neutral or very strongly deleterious. These results suggest that closely related species with similar genetic backgrounds but experiencing contrasting environments differ in the variance of deleterious fitness effects. PMID:21245893

  7. Cellular and behavioral effects of stilbene resveratrol analogues: implications for reducing the deleterious effects of aging.

    PubMed

    Joseph, James A; Fisher, Derek R; Cheng, Vivian; Rimando, Agnes M; Shukitt-Hale, Barbara

    2008-11-26

    Research suggests that polyphenolic compounds contained in fruits and vegetables that are rich in color may have potent antioxidant and anti-inflammatory activities. The present studies determined if stilbene (e.g., resveratrol) compounds would be efficacious in reversing the deleterious effects of aging in 19 month old Fischer 344 rats. Experiment I utilized resveratrol and six resveratrol analogues and examined their efficacies in preventing dopamine-induced decrements in calcium clearance following oxotremorine-induced depolarization in COS-7 cells transfected with M1 muscarinic receptors (MAChR) that we have shown previously to be sensitive to oxidative stressors. Experiment II utilized the most efficacious analogue (pterostilbene) from experiment I and fed aged rats a diet with a low (0.004%) or a high (0.016%) concentration of pterostilbene. Results indicated that pterostilbene was effective in reversing cognitive behavioral deficits, as well as dopamine release, and working memory was correlated with pterostilbene levels in the hippocampus. PMID:18954071

  8. 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

  9. 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

  10. 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

  11. Morphine has latent deleterious effects on the ventilatory responses to a hypoxic challenge

    PubMed Central

    May, Walter J.; Gruber, Ryan B.; Discala, Joseph F.; Puskovic, Veljko; Henderson, Fraser; Palmer, Lisa A.; Lewis, Stephen J.

    2014-01-01

    The aim of this study was to determine whether morphine depresses the ventilatory responses elicited by a hypoxic challenge (10% O2, 90% N2) in conscious rats at a time when the effects of morphine on arterial blood gas (ABG) chemistry, Alveolar-arterial (A-a) gradient and minute ventilation (VM) had completely subsided. In vehicle-treated rats, each episode of hypoxia stimulated ventilatory function and the responses generally subsided during each normoxic period. Morphine (5 mg/kg, i.v.) induced an array of depressant effects on ABG chemistry, A-a gradient and VM (via decreases in tidal volume). Despite resolution of these morphine-induced effects, the first episode of hypoxia elicited substantially smaller increases in VM than in vehicle-treated rats, due mainly to smaller increases in frequency of breathing. The pattern of ventilatory responses during subsequent episodes of hypoxia and normoxia changed substantially in morphine-treated rats. It is evident that morphine has latent deleterious effects on ventilatory responses elicited by hypoxic challenge. PMID:25045593

  12. Deleterious effects of benomyl and carbendazim on human placental trophoblast cells.

    PubMed

    Zhou, Jinghua; Xiong, Kang; Yang, Ye; Ye, Xiaoqing; Liu, Jing; Li, Feixue

    2015-01-01

    Benomyl and carbendazim are benzimidazole fungicides that are used throughout the world against a wide range of fungal diseases of agricultural products. There is as yet little information regarding the toxicity of benzimidazole fungicides to human placenta. In this study, we utilized human placental trophoblast cell line HTR-8/SVneo (HTR-8) to access the toxic effects of benomyl and carbendazim. Our data showed that these two fungicides decreased cell viability and the percentages of cells in G0/G1 phase, as well as induced apoptosis of HTR-8 cells. The invasion and migration of HTR-8 cells were significantly inhibited by benomyl and carbendazim. We further found that benomyl and carbendazim altered the expression of protease systems (MMPs/TIPMs and uPA/PAI-1) and adhesion molecules (integrin ?5 and ?1) in HTR-8 cells. Our present study firstly shows the deleterious effects of benomyl and carbendazim on placental cells and suggests a potential risk of benzimidazole fungicides to human reproduction. PMID:25530041

  13. Deleterious Effects of Hyperbaric Oxygen Treatment on Mortality and Pathological Changes in Nitrogen-Dioxide-Poisoned Dogs

    Microsoft Academic Search

    Y. Shechter; B. Pelled; G. Alroy; C. Lightig; M. Tirosh

    1975-01-01

    Nitrogen dioxide poisoning was experimentally produced in dogs. PO2, PCO2 and pH were measured in poisoned animals and during treatment with hyperbaric oxygen (OHP) lung lesions in both groups were evaluated. It is concluded that OHP has a deleterious effect both in terms of mortality and pathological changes.

  14. 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.

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

    PubMed

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

    2008-09-16

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

  16. Is It Happening? How to Avoid the Deleterious Effects of Plagiarism and Cheating in Your Courses

    ERIC Educational Resources Information Center

    Hall, Susan E.

    2011-01-01

    Plagiarism can be "plaguing" if it is not discussed, understood, and enforced by the professor right at the beginning of the course and throughout the semester. Students usually don't "have" to cheat or plagiarize; they do so mainly because "they can." Professors who turn a deaf ear or a blind eye to students who plagiarize create deleterious…

  17. Duration of Sexual Harassment and Generalized Harassment in the Workplace Over Ten Years: Effects on Deleterious Drinking Outcomes

    PubMed Central

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

    2012-01-01

    While harassment in the workplace has been linked to deleterious drinking outcomes, researchers have yet to examine the long-term effects of chronic workplace harassment. During a ten year longitudinal mail survey, university employees (N = 2265) were administered measures of sexual harassment, generalized workplace harassment, and problematic drinking. Using growth mixture modeling, two latent classes of workplace harassment emerged: infrequent and chronic. Demographic characteristics (gender, age, and race) predicted the shape of the trajectories and likelihood of class membership. As hypothesized, membership in the chronic harassment classes was linked to future problematic drinking, even after controlling for previous drinking. PMID:21745045

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

    PubMed

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

    2011-01-01

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

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

    PubMed Central

    Tronel, Claire; Rochefort, Gaël 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

  20. 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

  1. 4-Hydroxytamoxifen induces slight uncoupling of mitochondrial oxidative phosphorylation system in relation to the deleterious effects of tamoxifen.

    PubMed

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

    2002-10-15

    The use of tamoxifen (TAM) has been questioned on the chemotherapy and chemoprevention of breast cancer due to several estrogen receptor-independent cytotoxic effects. As an alternative, its more active metabolite 4-hydroxytamoxifen (OHTAM) has been proposed with presumed lower side effects. In this work, the potential OHTAM toxicity on rat liver mitochondrial bioenergetics in relation to the multiple deleterious effects of TAM was evaluated. OHTAM, at concentrations lower than those putatively reached in tissues following the administration of TAM, does not induce significant perturbations on the respiratory control ratio (RCR), ADP/O, transmembrane potential (DeltaPsi), phosphorylative capacity and membrane integrity of mitochondria. However, at high concentrations, OHTAM depresses the DeltaPsi, RCR and ADP/O, affecting the phosphorylation efficiency, as also inferred from the DeltaPsi fluctuations and pH changes associated with ADP phosphorylation. Moreover, OHTAM, at concentrations that stimulate the rate of state 4 respiration in parallel to the decrease in the DeltaPsi and phosphorylation rate, causes mitochondrial swelling and stimulates both ATPase and citrate synthase activities. However, the OHTAM-observed effects, at high concentrations, are not significant relatively to the damaging effects promoted by TAM and suggest alterations to mitochondrial functions due to proton leak across the mitochondrial inner membrane. PMID:12270594

  2. 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

  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. The deleterious effects of salinity stress on leafminers and their freshwater host

    Microsoft Academic Search

    LISA SCHILE; SUSAN MOPPER

    2006-01-01

    Salinity is an important cause of abiotic stress in wetland communities yet little is known about its consequences for freshwater plants and their insect herbivores. The goal of this study was to test the effect of salinity on a leafmining insect, Cerodontha iridiphora , and its herbaceous host plant, Iris hexagona . 2. Leafminer performance was evaluated on irises grown

  5. Hyperfractionation decreases the deleterious effects of conventional radiation fractionation on vertebral growth in animals

    SciTech Connect

    Hartsell, W.F.; Hanson, W.R.; Conterato, D.J.; Hendrickson, F.R.

    1989-06-15

    Craniospinal axis irradiation in the treatment of pediatric tumors is associated with serious long-term sequelae including decreased bone growth (short sitting stature). In this study, an animal model was used to determine the effects of smaller incremental doses of radiation on bone growth. Sprague-Dawley weanling rats were given 25 Gy to the spine in 8 to 9 days, with fraction sizes ranging from 1.0 to 1.8 Gy. The animals receiving smaller doses per fraction (1.0 or 1.25 Gy) showed significantly more growth of the vertebral bodies in the treated fields than animals given larger incremental doses (1.5 or 1.8 Gy). These findings indicate a protective effect on bone growth for hyperfractionated irradiation of vertebral bodies.

  6. 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 ?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

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

    PubMed

    Oumeddour, Abdelkader; Viennois, Emilie; Caira, Françoise; Decourbey, Clélia; Maqdasy, Salwan; Tahraoui, Abdelkrim; Baron, Silvère; Volle, David H; Lobaccaro, Jean-Marc A

    2014-04-11

    Liver X receptors LXR? (NR1H3) and LXR? (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 ER? (NR3A1) and ER? (NR3A2), and Lxr?/?. 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 ?g 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 Lxr?/?; those whose accumulation is repressed by the absence of Lxr?/?. 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 Lxr?/?. Altogether, our study shows that both nuclear receptors Lxr? and Lxr? are not only basally important for testicular physiology but could also have a preventive effect against estrogen-like endocrine disruptors. PMID:24333430

  8. 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

  9. Pretreatment with polyamines alleviate the deleterious effects of diuron in maize leaves.

    PubMed

    Durmu?, Nuran; Bekircan, Tuba

    2015-03-01

    The effects of diuron, a photosystem II inhibiting herbicide, on lipid peroxidation, photosynthetic pigments, soluble protein, proline contents and some antioxidant enzymes in maize leaves were studied and protective effects of polyamines against diuron toxicity were investigated. Diuron significantly increased lipid peroxidation, suggesting oxidative damage in the plants and proline content, while it decreased total chlorophyll, carotenoid and soluble protein levels in the leaves during the experiments. Pretreatment with polyamines statistically decreased lipid peroxidation induced by diuron and spermine (SPM) proved to be the most effective polyamine. Also, pretreatment with polyamines significantly prevented the losses of total chlorophyll, carotenoid and soluble protein induced by diuron. On the other hand, pretreatment with polyamines significantly increased proline contents of the leaves in comparison with the leaves treated with diuron. Superoxide dismutase (SOD), guaiacol peroxidase (GPX) and glutathione reductase (GR) activities increased in the leaves treated with diuron while catalase (CAT ) activity decreased. Pretreatment with spermidine (SPD) did not change significantly SOD activity at 24 and 72 hrs of diuron treatment but prevented the increase in SOD activity induced by diuron at 48 h. However, pretreatment with SPD increased GPX activity at 24 h and GR activity at 48 and 72 hrs. CAT activity in the leaves pretreated with SPD was similar to that of the leaves treated with diuron. Pretreatment with SPM prevented the increase in SOD activity induced by diuron at 48 h but significantly increased it at 72 h of diuron treatment. However, pretreatment with SPM did not significantly change GPX and GR activities during the experiments but reversed the decrease in CAT activity induced by diuron at 72 h. Pretreatment with putrescine (PUT) prevented the increase in SOD activity induced by diuron at 48 and 72 hrs while it increased GPX and GR activities at 48 h of diuron treatment. Also, the decrease in CAT activity induced by diuron at 72 h was completely prevented by PUT. It can be concluded that pretreatment of maize leaves with polyamines reduced the damage produced by diuron and the protective effects of polyamines against diuron toxicity were closely associated with antioxidant system. PMID:25740438

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. 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

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

    PubMed

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

    2012-04-01

    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 (µCT, 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

  16. Deleterious effects of an environmental noise on sleep and contribution of its physical components in a rat model

    Microsoft Academic Search

    J. J Bouyer; J. M Aran; A Courtiere; W Mayo; M Le Moal

    2004-01-01

    Sleep disturbances induced by environmental noise (EN) exposure are now well admitted. However, many contradictory conclusions and discrepancies have been reported, resulting from uncontrolled human factors or the use of artificial noises (pure tone). Thus, the development of an animal model appears to be a useful strategy for determining whether EN is deleterious to sleep. The aims of this study

  17. 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

  18. Ecological Effects in Malaria Vaccine Effectiveness in

    E-print Network

    Doyle, Martin

    Ecological Effects in Malaria Vaccine Effectiveness in Lilongwe, Malawi Cameron Taylor B component to a GlaxoSmithKline phase III trial vaccine trial so that researchers can better understand distribution and the ecological effects of both malaria transmission intensity and vaccine efficacy

  19. WS-SNPs&GO: a web server for predicting the deleterious effect of human protein variants using functional annotation

    PubMed Central

    2013-01-01

    Background SNPs&GO is a method for the prediction of deleterious Single Amino acid Polymorphisms (SAPs) using protein functional annotation. In this work, we present the web server implementation of SNPs&GO (WS-SNPs&GO). The server is based on Support Vector Machines (SVM) and for a given protein, its input comprises: the sequence and/or its three-dimensional structure (when available), a set of target variations and its functional Gene Ontology (GO) terms. The output of the server provides, for each protein variation, the probabilities to be associated to human diseases. Results The server consists of two main components, including updated versions of the sequence-based SNPs&GO (recently scored as one of the best algorithms for predicting deleterious SAPs) and of the structure-based SNPs&GO3d programs. Sequence and structure based algorithms are extensively tested on a large set of annotated variations extracted from the SwissVar database. Selecting a balanced dataset with more than 38,000 SAPs, the sequence-based approach achieves 81% overall accuracy, 0.61 correlation coefficient and an Area Under the Curve (AUC) of the Receiver Operating Characteristic (ROC) curve of 0.88. For the subset of ~6,600 variations mapped on protein structures available at the Protein Data Bank (PDB), the structure-based method scores with 84% overall accuracy, 0.68 correlation coefficient, and 0.91 AUC. When tested on a new blind set of variations, the results of the server are 79% and 83% overall accuracy for the sequence-based and structure-based inputs, respectively. Conclusions WS-SNPs&GO is a valuable tool that includes in a unique framework information derived from protein sequence, structure, evolutionary profile, and protein function. WS-SNPs&GO is freely available at http://snps.biofold.org/snps-and-go. PMID:23819482

  20. 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

    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 (?G D (o)) and functional activity parameters (K m and k cat) of different model proteins in the presence of various concentrations of urea and each non-methylamine osmolyte alone and in combination. We observed that (i) for each protein myo-inositol provides perfect counteraction at 1?2 ([myo-inositol]:[urea]) ratio, (ii) any concentration of sorbitol fails to refold urea denatured proteins if it is six times less than that of urea, and (iii) taurine regulates perfect counteraction in a protein specific manner; 1.5?2.0, 1.2?2.0 and 1.0?2.0 ([taurine]:[urea]) ratios for RNase-A, lysozyme and ?-lactalbumin, respectively. PMID:24039776

  1. Identification and analysis of deleterious human SNPs.

    PubMed

    Yue, Peng; Moult, John

    2006-03-10

    We have developed two methods of identifying which non-synonomous single base changes have a deleterious effect on protein function in vivo. One method, described elsewhere, analyzes the effect of the resulting amino acid change on protein stability, utilizing structural information. The other method, introduced here, makes use of the conservation and type of residues observed at a base change position within a protein family. A machine learning technique, the support vector machine, is trained on single amino acid changes that cause monogenic disease, with a control set of amino acid changes fixed between species. Both methods are used to identify deleterious single nucleotide polymorphisms (SNPs) in the human population. After carefully controlling for errors, we find that approximately one quarter of known non-synonymous SNPs are deleterious by these criteria, providing a set of possible contributors to human complex disease traits. PMID:16412461

  2. Salt potentiates methylamine counteraction system to offset the deleterious effects of urea on protein stability and function.

    PubMed

    Rahman, Safikur; Rehman, Md Tabish; Singh, Laishram R; Warepam, Marina; Ahmad, Faizan; Dar, Tanveer Ali

    2015-01-01

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

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

    PubMed Central

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

    2015-01-01

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

  4. Deleterious effects of selective serotonin reuptake inhibitor treatment on semen parameters in patients with lifelong premature ejaculation.

    PubMed

    Koyuncu, H; Serefoglu, E C; Ozdemir, A T; Hellstrom, W J

    2012-09-01

    Premature ejaculation (PE), the most common sexual dysfunctions in men, is characterized by loss or absence of ejaculatory control. PE can be classified as either a lifelong or acquired condition. Although the prevalence of lifelong PE is rather low in the general male population, recent studies demonstrated that the patients who seek treatment for their rapid ejaculation mostly report lifelong PE. Although no drug for PE has been approved by regulatory bodies, chronic selective serotonin reuptake inhibitors (SSRIs) proved to be effective in treating lifelong PE. Despite the rising use and known effects of antidepressants on ejaculation, only a few reports have evaluated the impact of these drugs on the male fertility. Thus, the aim of this review is to evaluate the efficacy and adverse effects of SSRIs on semen parameters of patients with lifelong PE as well as to assess the safety of this treatment among sexually active couples who desire to have a child. PMID:22573230

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

    E-print Network

    Agrawal, Aneil F.

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

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

    PubMed

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

    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

  7. Unexpected lack of deleterious effects of uranium on physiological systems following a chronic oral intake in adult rat.

    PubMed

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

  10. You have the right to understand: the deleterious effect of stress on suspects' ability to comprehend Miranda.

    PubMed

    Scherr, Kyle C; Madon, Stephanie

    2012-08-01

    Miranda v. Arizona (384 U.S. 436, 1966) required that suspects be explicitly warned of the right to avoid self-incrimination and the right to legal representation. This research was designed to examine whether stress, induced via an accusation of wrong-doing, undermined or enhanced suspects' ability to comprehend their Miranda rights. Participants were randomly assigned to either be accused (n = 15) or not accused (n = 15) of having cheated on an experimental task in a two-cell between-subjects experimental design. Results supported the hypothesis that stress undermines suspects' ability to comprehend their Miranda rights. Participants who were accused of cheating exhibited significantly lower levels of Miranda comprehension than participants who were not accused of cheating. The theoretical processes responsible for these effects and the implications of the findings for police interrogation are discussed. PMID:22849413

  11. 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.

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

    Microsoft Academic Search

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

    2010-01-01

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

  13. ROADS AND THEIR MAJOR ECOLOGICAL EFFECTS

    Microsoft Academic Search

    Richard T. T. Forman; Lauren E. Alexander

    1998-01-01

    A huge road network with vehicles ramifies across the land, representing a sur- prising frontier of ecology. Species-rich roadsides are conduits for few species. Roadkills are a premier mortality source, yet except for local spots, rates rarely limit population size. Road avoidance, especially due to traffic noise, has a greater ecological impact. The still-more-important barrier effect subdivides populations, with demographic

  14. Deleterious GRM1 mutations in schizophrenia.

    PubMed

    Ayoub, Mohammed Akli; Angelicheva, Dora; Vile, David; Chandler, David; Morar, Bharti; Cavanaugh, Juleen A; Visscher, Peter M; Jablensky, Assen; Pfleger, Kevin D G; Kalaydjieva, Luba

    2012-01-01

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

  15. Effect of deleterious nsSNP on the HER2 receptor based on stability and binding affinity with herceptin: a computational approach.

    PubMed

    Rajasekaran, R; George Priya Doss, C; Sudandiradoss, C; Ramanathan, K; Purohit, Rituraj; Sethumadhavan, Rao

    2008-06-01

    In this study, we identified the most deleterious non-synonymous SNP of ERBB2 (HER2) receptors by its stability and investigated its binding affinity with herceptin. Out of 135 SNPs, 10 are nsSNPs in the coding region, in which one of the nsSNP (SNPid rs4252633) is commonly found to be damaged by I-Mutant 2.0, SIFT and PolyPhen servers. With this effort, we modelled the mutant HER2 protein based on this deleterious nsSNP (rs4252633). The modeled mutant showed less stability than native HER 2 protein, based on both total energy of the mutant and stabilizing residues in the mutant protein. This is due to a deviation between the mutant and the native HER2, having an RMSD of about 2.81 A. Furthermore, we compared the binding efficiency of herceptin with native and mutant HER2 receptors. We found that herceptin has a high binding affinity with mutant HER2 receptor, with a binding energy of -24.40 kcal/mol, as compared to the native type, which has a binding energy of -15.26 kcal/mol due to six-hydrogen bonding and two salt bridges exist between herceptin and the mutant type, whereas the native type establishes four hydrogen bonds and two salt bridges with herceptin. This analysis portrays that mutant type has two additional hydrogen bonds with herceptin compared with the native type. Normal mode analysis also showed that the two amino acids, namely Asp596 and Glu598 of mutant HER2, forming additional hydrogen bonding with herceptin, had a slightly higher flexibility than the native type. Based on our investigations, we propose that SNPid rs4252633 could be the most deleterious nsSNP for HER2 receptor, and that herceptin could be the best drug for mutant compared to the native HER2 target. PMID:18510993

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

    EPA Science Inventory

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

  17. 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...

  18. Ecology of estuaries: Anthropogenic effects

    Microsoft Academic Search

    Kennish; Michael J. Kennish

    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

  19. Deleterious amino acid polymorphisms in Arabidopsis thaliana and rice.

    PubMed

    Günther, Torsten; Schmid, Karl J

    2010-06-01

    Plant genetic diversity has been mainly investigated with neutral markers, but large-scale DNA sequencing projects now enable the identification and analysis of different classes of genetic polymorphisms, such as non-synonymous single nucleotide polymorphisms (nsSNPs) in protein coding sequences. Using the SIFT and MAPP programs to predict whether nsSNPs are tolerated (i.e., effectively neutral) or deleterious for protein function, genome-wide nsSNP data from Arabidopsis thaliana and rice were analyzed. In both species, about 20% of polymorphic sites with nsSNPs were classified as deleterious; they segregate at lower allele frequencies than tolerated nsSNPs due to purifying selection. Furthermore, A. thaliana accessions from marginal populations show a higher relative proportion of deleterious nsSNPs, which likely reflects differential selection or demographic effects in subpopulations. To evaluate the sensitivity of predictions, genes from model and crop plants with known functional effects of nsSNPs were inferred with the algorithms. The programs predicted about 70% of nsSNPs correctly as tolerated or deleterious, i.e., as having a functional effect. Forward-in-time simulations of bottleneck and domestication models indicated a high power to detect demographic effects on nsSNP frequencies in sufficiently large datasets. The results indicate that nsSNPs are useful markers for analyzing genetic diversity in plant genetic resources and breeding populations to infer natural/artificial selection and genetic drift. PMID:20198468

  20. 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

  1. 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.

  2. Very slightly deleterious mutations and the molecular clock

    Microsoft Academic Search

    Tomoko Ohta

    1987-01-01

    Summary The model of very slightly deleterious mutations was examined from the standpoint of population genetics in relation to the molecular evolutionary clock. The distribution of selection coefficients of mutants (in terms of amino acid changes) with small effect is thought to be continuous around zero, with an average negative value. The variance of selection coefficients depends upon environmental diversity

  3. The dual action of epigallocatechin gallate (EGCG), the main constituent of green tea, against the deleterious effects of visible light and singlet oxygen-generating conditions as seen in yeast cells.

    PubMed

    Mitrica, Radu; Dumitru, Ioana; Ruta, Lavinia L; Ofiteru, Augustin M; Farcasanu, Ileana C

    2012-01-01

    Green tea extracts (GTEs) as well as their main component, the polyphenol epigallocatechin gallate (EGCG), are known for their versatile antioxidant, antimicrobial, antitumoral or anti-inflammatory effects. In spite of the huge beneficial action, there is increasing evidence that under certain conditions green tea and its components can be detrimental to living organisms. Using Saccharomyces cerevisiae strains with various defects in the response to oxidative stress, we found that GTEs or EGCG act in synergy with visible light, exhibiting either deleterious or protective effects depending on the solvent employed. Similar synergistic effects could be observed under singlet oxygen-generating conditions, such as light exposure in the presence of photosensitizers or UV-A irradiation, therefore solvent variance may represent a powerful tool to modulate the preparation of green tea extracts, depending on the intended target. PMID:22932216

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

    Microsoft Academic Search

    Joel R. Peck

    1994-01-01

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

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

    E-print Network

    Wright, Dawn Jeannine

    Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development the capacity to harvest wave energy off its coast as a clean, renewable resource. An important part of moving this agenda forward must include understanding the potential effects of wave energy technology

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

    E-print Network

    Ecological Effects of Wave Energy Development in the Pacific Northwest A Scientific Workshop Technical Memorandum NMFS-F/SPO-92 #12;#12;Ecological Effects of Wave Energy Development in the Pacific Service; Justin Klure, Oregon Wave Energy Trust; Greg McMurray, Oregon Department of Land Conservation

  7. Effective discharge analysis of ecological processes in streams

    USGS Publications Warehouse

    Doyle, M.W.; Stanley, E.H.; Strayer, D.L.; Jacobson, R.B.; Schmidt, J.C.

    2005-01-01

    [1] Discharge is a master variable that controls many processes in stream ecosystems. However, there is uncertainty of which discharges are most important for driving particular ecological processes and thus how flow regime may influence entire stream ecosystems. Here the analytical method of effective discharge from fluvial geomorphology is used to analyze the interaction between frequency and magnitude of discharge events that drive organic matter transport, algal growth, nutrient retention, macroinvertebrate disturbance, and habitat availability. We quantify the ecological effective discharge using a synthesis of previously published studies and modeling from a range of study sites. An analytical expression is then developed for a particular case of ecological effective discharge and is used to explore how effective discharge varies within variable hydrologic regimes. Our results suggest that a range of discharges is important for different ecological processes in an individual stream. Discharges are not equally important; instead, effective discharge values exist that correspond to near modal flows and moderate floods for the variable sets examined. We suggest four types of ecological response to discharge variability: discharge as a transport mechanism, regulator of habitat, process modulator, and disturbance. Effective discharge analysis will perform well when there is a unique, essentially instantaneous relationship between discharge and an ecological process and poorly when effects of discharge are delayed or confounded by legacy effects. Despite some limitations the conceptual and analytical utility of the effective discharge analysis allows exploring general questions about how hydrologic variability influences various ecological processes in streams. Copyright 2005 by the American Geophysical Union.

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

    Microsoft Academic Search

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

    It is now well established that subthalamic nucleus high-frequency stimulation (STN HFS) alleviates motor problems in Parkinson's disease. However, its efficacy for cognitive function remains a matter of debate. The aim of this study was to assess the effects of STN HFS in rats performing a visual attentional task. Bilateral STN HFS was applied in intact and in bilaterally dopamine

  9. Reversal of the deleterious effects of chronic dietary HFCS-55 intake by PPAR-? agonism correlates with impaired NLRP3 inflammasome activation.

    PubMed

    Collino, Massimo; Benetti, Elisa; Rogazzo, Mara; Mastrocola, Raffaella; Yaqoob, Muhammed M; Aragno, Manuela; Thiemermann, Christoph; Fantozzi, Roberto

    2013-01-15

    Although high-fructose corn syrup (HFCS-55) is the major sweetener in foods and soft-drinks, its potential role in the pathophysiology of diabetes and obesity ("diabesity") remains unclear. Peroxisome-proliferator activated receptor (PPAR)-? agonists have never been tested in models of sugar-induced metabolic abnormalities. This study was designed to evaluate (i) the metabolic and renal consequences of HFCS-55 administration (15% wt/vol in drinking water) for 30 weeks on male C57Bl6/J mice and (ii) the effects of the selective PPAR-? agonist GW0742 (1 mg/kg/day for 16 weeks) in this condition. HFCS-55 caused (i) hyperlipidemia, (ii) insulin resistance, and (iii) renal injury/inflammation. In the liver, HFCS-55 enhanced the expression of fructokinase resulting in hyperuricemia and caused abnormalities in known insulin-driven signaling events. In the kidney, HFCS-55 enhanced the expression of the NLRP3 (nucleotide-binding domain and leucine-rich-repeat-protein 3) inflammasome complex, resulting in caspase-1 activation and interleukin-1? production. All of the above effects of HFCS-55 were attenuated by the specific PPAR-? agonist GW0742. Thus, we demonstrate for the first time that the specific PPAR-? agonist GW0742 attenuates the metabolic abnormalities and the renal dysfunction/inflammation caused by chronic HFCS-55 exposure by preventing upregulation of fructokinase (liver) and activation of the NLRP3 inflammasome (kidney). PMID:23103566

  10. Exercise before and during pregnancy prevents the deleterious effects of maternal high-fat feeding on metabolic health of male offspring.

    PubMed

    Stanford, Kristin I; Lee, Min-Young; Getchell, Kristen M; So, Kawai; Hirshman, Michael F; Goodyear, Laurie J

    2015-02-01

    The intrauterine environment during pregnancy is a critical factor in the development of diabetes and obesity in offspring. To determine the effects of maternal exercise during pregnancy on the metabolic health of offspring, 6-week-old C57BL/6 virgin female mice were fed a chow (21%) or high-fat (60%) diet and divided into four subgroups: trained (housed with running wheels for 2 weeks preconception and during gestation), prepregnancy trained (housed with running wheels for 2 weeks preconception), gestation trained (housed with running wheels during gestation), or sedentary (static cages). Male offspring were chow fed, sedentary, and studied at 8, 12, 24, 36, and 52 weeks of age. Offspring from chow-fed dams that trained both before and during gestation had improved glucose tolerance beginning at 8 weeks of age and continuing throughout the 1st year of life, and at 52 weeks of age had significantly lower serum insulin concentrations and percent body fat compared with all other groups. High-fat feeding of sedentary dams resulted in impaired glucose tolerance, increased serum insulin concentrations, and increased percent body fat in offspring. Remarkably, maternal exercise before and during gestation ameliorated the detrimental effect of a maternal high-fat diet on the metabolic profile of offspring. Exercise before and during pregnancy may be a critical component for combating the increasing rates of diabetes and obesity. PMID:25204976

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

    PubMed

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

    2013-12-01

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

  12. Symbiosis-promoting and deleterious effects of NopT, a novel type 3 effector of Rhizobium sp. strain NGR234.

    PubMed

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

    2008-07-01

    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

  13. Prediction of deleterious functional effects of non-synonymous single nucleotide polymorphisms in human nuclear receptor genes using a bioinformatics approach.

    PubMed

    Liu, Ya-He; Li, Chun Guang; Zhou, Shu-Feng

    2009-12-01

    The nuclear receptor (NR) superfamily represents an important group of regulating factors that control the expression of a number of target genes including those encoding important drug metabolizing enzymes and drug transporters. Single nucleotide polymorphism (SNP) is the most common mutation in the human genome and a large number of SNPs have been identified to date. It is unlikely to examine the functional impact of all these mutations using an experimental approach. As such, we employed two algorithms, Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping (PolyPhen) to predict the impact of non-synonymous SNPs (nsSNPs) on NR activities and disease susceptibility. We identified 442 nsSNPs in a systematic screening of 48 human NR genes. Using SIFT, of 442 amino acid substitutions, 289 (65.38%) were classified as "intolerant". The PolyPhen program classified 269 (60.86%) of them as "probably damaging" or "possibly damaging". The results from the two algorithms were in concordance. Among the 442 mutations, 229 of them have been functionally characterized. SIFT predicted 192 of these nsSNPs as "intolerant", resulting in a correct prediction rate of 83.84%, while PolyPhen gave a prediction rate of 76.86%. For 216 nsSNPs of the androgen receptor gene, 149 nsSNPs have been functionally studied and most (121) of them resulted in a reduction of receptor activity. SIFT sorted 187 out of 216 as "intolerant" (86.57%) and PolyPhen identified 159 out of 216 as "potentially intolerant" (73.61%). These results indicate that both SIFT and PolyPhen are useful and efficient tools to predict the functional effects of nsSNPs of human NR genes. PMID:20050372

  14. Maintenance of Genetic Variability under the Pressure of Neutral and Deleterious Mutations in a Finite Population

    PubMed Central

    Li, Wen-Hsiung

    1979-01-01

    In order to assess the effect of deleterious mutations on various measures of genic variation, approximate formulas have been developed for the frequency spectrum, the mean number of alleles in a sample, and the mean homozygosity; in some particular cases, exact formulas have been obtained. The assumptions made are that two classes of mutations exist, neutral and deleterious, and that selection is strong enough to keep deleterious alleles in low frequencies, the mode of selection being either genic or recessive. The main findings are: (1) If the expected value (q) of the sum of the frequencies of deleterious alleles is about 10% or less, then the presence of deleterious alleles causes only a minor reduction in the mean number of neutral alleles in a sample, as compared to the case of q = 0. Also, the low- and intermediate-frequency parts of the frequency spectrum of neutral alleles are little affected by the presence of deleterious alleles, though the high-frequency part may be changed drastically. (2) The contribution of deleterious mutations to the expected total number of alleles in a sample can be quite large even if q is only 1 or 2%. (3) The mean homozygosity is roughly equal to (1—2q)/(1+?1), where ?1 is twice the number of new neutral mutations occurring in each generation in the total population. Thus, deleterious mutations increase the mean heterozygosity by about 2q/(1+?1). The present results have been applied to study the controversial problem of how deleterious mutations may affect the testing of the neutral mutation hypothesis. PMID:488709

  15. Ecological and evolutionary effects of stickleback on community structure.

    PubMed

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

    2013-01-01

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

  16. Ecological effects of the North Atlantic Oscillation

    Microsoft Academic Search

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

    2001-01-01

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

  17. Spatial heterogeneity in the strength of selection against deleterious alleles and the mutation load.

    PubMed

    Roze, D

    2012-09-01

    According to current estimates of genomic deleterious mutation rates (which are often of the order 0.1-1) the mutation load (defined as a reduction in the average fitness of a population due to the presence of deleterious alleles) may be important in many populations. In this paper, I use multilocus simulations to explore the effect of spatial heterogeneity in the strength of selection against deleterious alleles on the mutation load (for example, it has been suggested that stressful environments may increase the strength of selection). These simulations show contrasted results: in some situations, spatial heterogeneity may greatly reduce the mutation load, due to the fact that migrants coming from demes under stronger selection carry relatively few deleterious alleles, and benefit from a strong advantage within demes under weaker selection (where individuals carry many more deleterious alleles); in other situations, however, deleterious alleles accumulate within demes under stronger selection, due to migration pressure from demes under weaker selection, leading to fitness erosion within those demes. This second situation is more frequent when the productivity of the different demes is proportional to their mean fitness. The effect of spatial heterogeneity is greatly reduced, however, when the response to environmental differences is inconsistent across loci. PMID:22588129

  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. 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

  20. 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

  1. [Ecological effects of utilizing non-timber forest products].

    PubMed

    Yang, Jie; Luan, Xiao-feng

    2011-03-01

    Non-timber forest products (NTFPs) include all plant materials other than timber, such as seeds, flowers, fruits, leaves, roots, bark, latex, resins, and other non-wood plant parts. The significant role of NTFPs in improving local people's lives and forest biodiversity conservation has been widely accepted. However, many studies in past decades indicated that NTFPs utilization had various ecological effects on different levels, from plant individual and population to community and forest ecosystem, depending not only on the plant parts extracted and their biological or ecological attributes, but also on the harvest forms. This paper reviewed the research progress about the effects of the utilization of NTFPs from biological and ecological aspects, and discussed some research problems and research priorities. PMID:21657041

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

    NASA Astrophysics Data System (ADS)

    Good, Benjamin; Desai, Michael

    2013-03-01

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

  3. Pesticide effects on freshwater zooplankton: an ecological perspective

    Microsoft Academic Search

    T Hanazato

    2001-01-01

    The effects of pesticides on zooplankton are reviewed and their ecological significance is discussed. Toxicity is shown to vary depending on animal species, genotype, life stage, and size at birth. Natural stresses such as food shortage, oxygen depletion and odors of potential predators can also affect toxicity. Populations in the growth phase are vulnerable to pesticides but have the potential

  4. Effective discharge analysis of ecological processes in streams

    Microsoft Academic Search

    Martin W. Doyle; Emily H. Stanley; David L. Strayer; Robert B. Jacobson; John C. Schmidt

    2005-01-01

    Discharge is a master variable that controls many processes in stream ecosystems. However, there is uncertainty of which discharges are most important for driving particular ecological processes and thus how flow regime may influence entire stream ecosystems. Here the analytical method of effective discharge from fluvial geomorphology is used to analyze the interaction between frequency and magnitude of discharge events

  5. 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...

  6. 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...

  7. AGRONOMIC AND ECOLOGICAL EFFECTS OF INNOVATIVE AND TRADITIONAL CROPPING SYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recently developed agricultural practices have each been shown to result in improvements in crop productivity, soil quality, and/or environmental conservation. However, few studies have examined the agronomic and ecological effects of these innovative production practices when used as part of a whol...

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

    E-print Network

    542 Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska By Roger J. ReedKernan, Director Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska By ROGER J. REED Literature cited 14 #12;#12;Some Effects of DDT on the Ecology of Salmon Streams in Southeastern Alaska

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

    PubMed

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

    2014-06-13

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

  10. 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…

  11. 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.

  12. Ecological Effects of Serial Impoundment on the Cotter River, Australia

    Microsoft Academic Search

    Susan Nichols; Richard Norris; William Maher; Martin Thoms

    2006-01-01

    This study examines the ecological effects of serial impoundments (three dams) on a rocky upland stream in southeastern Australia.\\u000a Physical, chemical and biological changes were quantified and interpreted within a three-level hierarchy of effects model\\u000a developed previously by Petts [1984, Impounded Rivers. John Wiley and Sons, New York] and the Australian Rivers Assessment\\u000a System (AUSRIVAS) to predict pre-dam biota. First-order

  13. 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 ...

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

    NSDL National Science Digital Library

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

    2003-04-01

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

  15. Enhanced suppression of plant growth through production of L-tryptophan-derived compounds by deleterious rhizobacteria

    Microsoft Academic Search

    Muhammad Sarwar; Robert J. Kremer

    1995-01-01

    Plant-growth-suppressive activity of deleterious rhizobacteria (DRB) may be due to production of metabolites absorbed through roots. Auxins produced in high concentrations in the rhizosphere by DRB contribute to reduced root growth. Selected DRB able to produce excessive amounts of auxin compounds for suppression of weed seedling growth may be effective for biological control of weeds. The objectives to this study

  16. Ecology of estuaries

    SciTech Connect

    Kennish, M.J. (Rutgers--the State Univ., New Brunswick, NJ (United States))

    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.

  17. 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

  18. 21 CFR 509.6 - Added poisonous or deleterious substances.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS UNAVOIDABLE CONTAMINANTS IN ANIMAL FOOD AND FOOD-PACKAGING MATERIAL General Provisions § 509.6 Added poisonous or deleterious...

  19. The inevitability of unconditionally deleterious substitutions during adaptation.

    PubMed

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

    2014-05-01

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

  20. PHYSIOLOGICAL A;'IlD CHEMICAL ECOLOGY Effects of Sessile Whitefly Nymphs (Homoptera: Aleyrodidae) on

    E-print Network

    Inbar, Moshe

    PHYSIOLOGICAL A;'IlD CHEMICAL ECOLOGY Effects of Sessile Whitefly Nymphs (Homoptera: Aleyrodidae. These generalist herbivores belong to different feeding guilds. Sessile whitefly nymphs complete their development

  1. Statistical Ecology and Environmental Statistics for Cost-Effective Ecological Synthesis and Environmental Analysis

    Microsoft Academic Search

    Ganapati P. Patil

    Ecology is undergoing some major changes in response to changing times of societal concerns coupled with remote sensing information and computer technology. Both theoretical and applied ecology are using more of statistical thought processes and procedures with advancing software and hardware to satisfy public policy and research, variously incorporating sample survey data, intensive site-specific data, and re- mote sensing image

  2. Pesticide effects on freshwater zooplankton: an ecological perspective.

    PubMed

    Hanazato, T

    2001-01-01

    The effects of pesticides on zooplankton are reviewed and their ecological significance is discussed. Toxicity is shown to vary depending on animal species, genotype, life stage, and size at birth. Natural stresses such as food shortage, oxygen depletion and odors of potential predators can also affect toxicity. Populations in the growth phase are vulnerable to pesticides but have the potential to recover rapidly from the damage. Pesticides may affect the population dynamics by controlling individual survival and reproduction, and by altering the sex ratio. Furthermore, toxic chemicals may control predation risk by changing swimming behavior and body morphology, and this in turn influences the population dynamics. Many zooplankton display morphological and behavioral responses to predators when exposed to their odor-producing chemicals. However, pesticides induce a maladaptive response to predator odor, and this poses an ecological risk. The following patterns are recognized as effects of pesticides at the community and ecosystem levels: (1) induction of dominance by small species; (2) an increase of species richness and diversity; and (3) elongation of the food chain and reduction of energy transfer efficiency from primary producers to top predators. PMID:11202648

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

    PubMed

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

    2015-03-01

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

  4. Some Parameters of Teacher Effectiveness as Assessed by an Ecological Approach

    ERIC Educational Resources Information Center

    Scott, Myrtle

    1977-01-01

    This experiment explored the applicability of naturalistic methods of ecological psychology to the study of teacher behavior. Some differences were found between teachers who had been identified as effective or ineffective. The ecological methodology is thought to be a fruitful one for the study of teacher effectiveness. (Author/JKS)

  5. GLOBAL CHANGE ECOLOGY -ORIGINAL RESEARCH Local effects of a global problem: modelling the risk of parasite-

    E-print Network

    Poulin, Robert

    cascading effects through ecological networks such as food webs (Ottersen et al. 2001; Stenseth et al. 2002GLOBAL CHANGE ECOLOGY - ORIGINAL RESEARCH Local effects of a global problem: modelling the risk to make realistic predictions about these conse- quences. Here, we adapt a simulation model developed

  6. Epistasis between deleterious mutations and the evolution of

    E-print Network

    Bonhoeffer, Sebastian

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

  7. On the average coefficient of dominance of deleterious spontaneous mutations.

    PubMed Central

    García-Dorado, A; Caballero, A

    2000-01-01

    T. Mukai and co-workers in the late 1960s and O. Ohnishi in the 1970s carried out a series of experiments to obtain direct estimates of the average coefficient of dominance (h) of minor viability mutations in Drosophila melanogaster. The results of these experiments, although inconsistent, have been interpreted as indicating slight recessivity of deleterious mutations, with h approximately 0.4. Mukai obtained conflicting results depending on the type of heterozygotes used, some estimates suggesting overdominance and others partial dominance. Ohnishi's estimates, based on the ratio of heterozygous to homozygous viability declines, were more consistent, pointing to the above value. However, we have reanalyzed Ohnishi's data, estimating h by the regression method, and obtained a much smaller estimate of approximately 0.1. This significant difference can be due partly to the different weighting implicit in the estimates, but we suggest that this is not the only explanation. We propose as a plausible hypothesis that a putative nonmutational decline in viability occurring in the first half of Ohnishi's experiment (affecting both homozygotes and heterozygotes) has biased upward the estimates from the ratio, while it would not bias the regression estimates. This hypothesis also explains the very high h approximately 0.7 observed in Ohnishi's high-viability chromosomes. By constructing a model of spontaneous mutations using parameters in the literature, we investigate the above possibility. The results indicate that a model of few mutations with moderately large effects and h approximately 0.2 is able to explain the observed estimates and the distributions of homozygous and heterozygous viabilities. Accounting for an expression of mutations in genotypes with the balancer chromosome Cy does not alter the conclusions qualitatively. PMID:10924491

  8. 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.

  9. 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.

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

    E-print Network

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

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

    PubMed

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

    2012-11-01

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

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

    E-print Network

    Juliano, Steven A.

    concentrate on the best-studied invasive mosquito, Aedes albopictus, evaluating the application of basic ecological theory to invasions by Aedes albopictus. We develop a model based on observations of Aedes­host systems. Keywords Aedes albopictus, apparent competition, Culicidae, disease ecology, disease vectors

  13. 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…

  14. Prediction of the deleterious nsSNPs in ABCB transporters.

    PubMed

    Li, Yanhong; Wang, Yonghua; Li, Yan; Yang, Ling

    2006-12-22

    The non-synonymous SNPs (nsSNPs) in coding regions, neutral or deleterious, could lead to the alteration of the function or structure of proteins. We have developed the computational models to analyze the deleterious nsSNPs in the transporters and predict ones in ABCB (ATP-binding cassette B) transporters of interest. The RPLS (ridge partial least square) and LDA (linear discriminant analysis) methods were applied to the problem, by training on a selection of datasets from a specified source, i.e., human transporters. The best combination of datasets and prediction attributes was ascertained. The prediction accuracy of the theoretical RPLS model for the training and testing sets is 84.8% and 80.4%, respectively (LDA: 84.3% and 80.4%), which indicates the models are reasonable and may be helpful for pharmacogenetics studies. PMID:17141228

  15. [Environmental behavior and ecological effect of polydimethylsiloxane: a review].

    PubMed

    Yang, Shang-Yuan; Li, Xin; Yang, Jia; Shen, Chao-Feng; Yu, Hua-Dong; Lu, Kang

    2012-08-01

    Polydimethylsiloxane (PDMS) is widely used in industrial products, medical and health care products, and personal care products. In the treatment process of sewage, PDMS can be hardly biodegraded but enter the environment mainly through the discharge of excess sludge, and only a small amount of PDMS adsorbed on the suspended solids or sludge particle surface is discharged into water body and sediment with treated sewage. There is no enough evidence to verify that PDMS can vertically migrate in sediment. The degradation of PDMS in sediment is very slow, but PDMS can be degraded in different types of soils. PDMS has less risk to aquatic ecosystem, and no apparent acute toxicity to benthos. In soil environment, PDMS and its degradation products have no significant effects on the soil microorganisms, soil animals, and crops. Though a few studies indicated that PDMS and its degradation products have relatively low ecological toxicity in various environments, it is still very important to clarify the potential threat of PDMS to the environment because of the increasingly large number of PDMS being produced and used. PMID:23189715

  16. Ecological effects after an alum treatment in Spring Lake, Michigan.

    PubMed

    Steinman, Alan D; Ogdahl, Mary

    2008-01-01

    A whole-lake alum treatment was applied to eutrophic Spring Lake during October and November 2005. Eight months later, an ecological assessment of the lake was performed and compared with data collected in 2003 and 2004. Field measurements showed reduced soluble reactive phosphorus (SRP) and total phosphorus (TP) concentrations in the water column the summer after the alum application, but chlorophyll levels and irradiance profiles were not significantly affected. Total macroinvertebrate density declined significantly in 2006 compared with 2004, with chaoborids and oligochaetes experiencing the greatest reductions. Internal phosphorus release rates, measured using sediment cores incubated in the laboratory, ranged from -0.052 to 0.877 mg TP m(-2) d(-1) under anaerobic conditions. These internal loading rates were significantly lower than those measured in 2003 at three out of four sites. Mean porewater SRP concentrations were lower in 2006 than in 2003, but this difference was statistically significant only under aerobic conditions. The NaOH-extractable SRP fraction in the sediment was also significantly lower in 2006 compared with 2003, whereas the HCl-extractable SRP sediment fraction showed the opposite pattern. Overall, these results indicate that the alum treatment effectively reduced internal P loading in Spring Lake. However, water column phosphorus concentrations remain high in this system, presumably due to high external loading levels, and may account for the high chlorophyll levels. An integrated watershed management approach that includes reducing internal and external inputs of P is necessary to address the cultural eutrophication of Spring Lake. PMID:18178875

  17. 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...

  18. 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...

  19. COMMUNITY ECOLOGY -ORIGINAL PAPER Individual and combined effects of multiple pathogens on Pacific

    E-print Network

    Rohr, Jason

    COMMUNITY ECOLOGY - ORIGINAL PAPER Individual and combined effects of multiple pathogens on Pacific often encounter multiple pathogens simultaneously, which can lead to additive, antagonistic host populations. However, ecologists and managers often overlook the influence of pathogen combi

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

    E-print Network

    Tiegs, Scott

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

  1. 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...

  2. Extraordinary Sex Ratios: Cultural Effects on Ecological Consequences

    PubMed Central

    Molnár, Ferenc; Caraco, Thomas; Korniss, Gyorgy

    2012-01-01

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

  3. Extraordinary sex ratios: cultural effects on ecological consequences.

    PubMed

    Molnár, Ferenc; Caraco, Thomas; Korniss, Gyorgy

    2012-01-01

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

  4. Effects of Roads and Traffic on Wildlife Populations and Landscape Function Road Ecology is Moving toward Larger Scales

    Microsoft Academic Search

    Ree van R; J. A. G. Jaeger; Grift van der E. A; A. P. Clevenger

    2011-01-01

    Road ecology has developed into a significant branch of ecology with steady growth in the number of refereed journal articles, books, conferences, symposia, and “best practice” guidelines being produced each year. The main objective of this special issue of Ecology and Society is to highlight the need for studies that document the population, community, and ecosystem-level effects of roads and

  5. Flow effects on benthic stream invertebrates and ecological processes

    NASA Astrophysics Data System (ADS)

    Koprivsek, Maja; Brilly, Mitja

    2010-05-01

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

  6. Climate Change Has Cascading Ecological Effects on Mountain Ecosystems

    NASA Astrophysics Data System (ADS)

    Fagre, D. B.

    2007-12-01

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

  7. Cascading climate effects and related ecological consequences during past centuries

    NASA Astrophysics Data System (ADS)

    Naef-Daenzer, B.; Luterbacher, J.; Nuber, M.; Rutishauser, T.; Winkel, W.

    2012-06-01

    The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using path analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea - Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within animal populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and population dynamics on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the path model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, and consequently, tit population minima during the "Maunder Minimum" (1650-1720) and the Little Ice Age Type Event I (1810-1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, an unprecedented increase of the population. A verification of the structural equation model against two independent data series corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large scale climate conditions substantially affect major life-history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.

  8. Magnesium hydroxide as a complementary aluminium-free phosphate binder to moderate doses of oral calcium in uraemic patients on chronic haemodialysis: lack of deleterious effect on bone mineralisation.

    PubMed

    Morinière, P; Vinatier, I; Westeel, P F; Cohemsolal, M; Belbrik, S; Abdulmassih, Z; Hocine, C; Marie, A; Leflon, P; Roche, D

    1988-01-01

    To control hyperphosphataemia without hyperaluminaemia, A1(OH)3, which was given in addition to high doses of oral calcium, was replaced by Mg(OH)2 for 6 months in 20 haemodialysed patients and for 20 months in 12. The treatment during the control period was 110 +/- 91 mmol/day of oral calcium element given as CaCO3 and/or Calcium Sorbisterit and 1.05 +/- 1.47 g/day of A1(OH)3. Haemodialysis treatment was 4 h, thrice weekly. To prevent hypermagnesaemia, dialysate magnesium was decreased from 0.75 mmol/l to 0.375 mmol/l. After a control period of 3 months, Mg(OH)2 was given at a mean dose of 2.6 +/- 2 g/day and oral calcium supplements were decreased to 76 mmol/day. Two subsequent bone histomorphometry studies were performed at 8 month intervals in four patients and at 20 month intervals in seven patients. The results show a good control of plasma calcium (mean +/- SD: 2.43 +/- 0.1 mumol/l); phosphate (1.76 +/- 0.4 to 1.66 +/- 0.3 mmol/l); aluminum (1.3 +/- 0.1 mumol/l to 0.6 +/- 0.1 mumol/l); alkaline phosphatase (135 +/- 65 to 125 +/- 40 IU); and PTH fragments (PTH C terminal decreased from 260 +/- 214 to 185 +/- 182 pg/ml, PTH medium from 4185 +/- 5113 to 2270 +/- 4880 pg/ml). Plasma magnesium increased from 0.96 +/- 0.2 to 1.54 +/- 0.2 mmol/l. Bone histomorphometry shows no change in mineralisation, and a borderline decrease of resorption parameters. The main side-effects are (1) diarrhoea, which was well controlled by transient treatment with karaya gum, and (2) an increased need for potassium binders.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3146723

  9. Compensatory mutations occur within the electrostatic interaction range of deleterious mutations in protein structure.

    PubMed

    Bhattacherjee, Amrita; Mallik, Saurav; Kundu, Sudip

    2015-01-01

    A compensatory mutation (CM) counter balances lethal effects of a deleterious mutation (DM), ensuring the persistence of both through natural selection. However, little is known about the biological aspects of CMs those restore the structural alterations of proteins caused by slightly DMs. Here, by analyzing the evolution of the UDP-glycosyltransferase 73B4 protein among monocot-dicot plants, we investigate the occurrence of CMs around slightly DMs in 3D space. Our results illustrate that CMs exhibit significantly higher tendency to occur within the range of electrostatic interaction around the slightly DMs, compared to occurring randomly in the protein. PMID:25399321

  10. 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

  11. The socioeconomic effects of uranium development in south Texas: a human ecological approach

    E-print Network

    Hopkins, Pamela Chris

    1982-01-01

    THE SOCIOECONOMIC FFFECTS OF URANIUM DEVELOPMENT IN SOUTH TEXAS: A HUMAN ECOLOGICAL APPROACH A Thesis by PAMELA CHRIS HOPKINS Submitted to tne Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1962 Major Subject: Sociology THE SOCIOECONOMIC EFFECTS OF URANIUM DEVELOPMENT IN SOUTH TEXAS: A HUMAN ECOLOGICAL APPROACH A Thesis by PAMELA CHRIS HOPKINS Approved as to style and content by: (Chairman of Committee...

  12. The socioeconomic effects of uranium development in south Texas: a human ecological approach 

    E-print Network

    Hopkins, Pamela Chris

    1982-01-01

    THE SOCIOECONOMIC FFFECTS OF URANIUM DEVELOPMENT IN SOUTH TEXAS: A HUMAN ECOLOGICAL APPROACH A Thesis by PAMELA CHRIS HOPKINS Submitted to tne Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree... of MASTER OF SCIENCE August 1962 Major Subject: Sociology THE SOCIOECONOMIC EFFECTS OF URANIUM DEVELOPMENT IN SOUTH TEXAS: A HUMAN ECOLOGICAL APPROACH A Thesis by PAMELA CHRIS HOPKINS Approved as to style and content by: (Chairman of Committee...

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

    Microsoft Academic Search

    AIMEE J. WELDON; NICK M. HADDAD

    2005-01-01

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

  14. The effects of the environment and ecology projects on lake management and water quality

    Microsoft Academic Search

    Cengiz Koç

    2008-01-01

    In this study, the characteristics, benefits, and effects of the environment and ecology project, which has been implemented\\u000a in Turkey for the first time to restore the natural life that has been spoilt and the ecological balance of Lake Bafa located\\u000a in Great Meander Basin, are searched. Moreover, the water samples taken from the stations that were spotted in the

  15. 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.

  16. Dimension effects of enclosures on ecological processes in pelagic systems

    Microsoft Academic Search

    Gry Mine Berg; Patricia M. Glibert; Chung-Chi Chen

    1999-01-01

    Several characteristics inherent to experimental ecosystems were examined for their influence on ecological processes in five cylindrical indoor benthic-pelagic enclosures of different size and shape. Ecosystem development diverged significantly among the mesocosm dimensions even though environmental parameters such as surface photosynthetically available radiation (400-700 nm), turbulence intensity, water exchange rate, and nutrient input were held constant across systems. Here we

  17. Original article The deleterious effects of human erythropoietin

    E-print Network

    Paris-Sud XI, Université de

    cells irrespectively of their sex, they could not reproduce and no milk could be obtained from them. These animals died prematurely. In these animals, the EPO gene was there- fore expressed at a low but supraphysiological level in organs other than the mammary gland. These experiments show that transgenic animals

  18. Some Parameters of Teacher Effectiveness as Assessed by an Ecological Approach.

    ERIC Educational Resources Information Center

    Scott, Myrtle

    1969-01-01

    To identify parameters of teacher effectiveness, this study uses an ecological approach. Since setting, which includes not only physical surroundings but also the dynamic of activity, has a coercive effect on behavior, a teacher's ability to establish appropriate settings should be an accurate measure of effectiveness. Five head teachers in a…

  19. Review of Ecological Effects of Roads on Terrestrial and Aquatic Communities

    Microsoft Academic Search

    Stephen C. Trombulak; Christopher A. Frissell

    2000-01-01

    Roads are a widespread and increasing feature of most landscapes. We reviewed the scientific liter- ature on the ecological effects of roads and found support for the general conclusion that they are associated with negative effects on biotic integrity in both terrestrial and aquatic ecosystems. Roads of all kinds have seven general effects: mortality from road construction, mortality from collision

  20. Ecology 2005 19, 648655

    E-print Network

    Altwegg, Res

    Functional Ecology 2005 19, 648­655 © 2005 British Ecological Society 648 Blackwell Publishing, Ltd virginianum, trait-mediated indirect effects Functional Ecology (2005) 19, 648­655 doi: 10.1111/j.1365

  1. Predicting deleterious non-synonymous single nucleotide polymorphisms in signal peptides based on hybrid sequence attributes.

    PubMed

    Qin, Wenli; Li, Yizhou; Li, Juan; Yu, Lezheng; Wu, Di; Jing, Runyu; Pu, Xuemei; Guo, Yanzhi; Li, Menglong

    2012-02-01

    Signal peptides play a crucial role in various biological processes, such as localization of cell surface receptors, translocation of secreted proteins and cell-cell communication. However, the amino acid mutation in signal peptides, also called non-synonymous single nucleotide polymorphisms (nsSNPs or SAPs) may lead to the loss of their functions. In the present study, a computational method was proposed for predicting deleterious nsSNPs in signal peptides based on random forest (RF) by incorporating position specific scoring matrix (PSSM) profile, SignalP score and physicochemical properties. These features were optimized by the maximum relevance minimum redundancy (mRMR) method. Then, a cost matrix was used to minimize the effect of the imbalanced data classification problem that usually occurred in nsSNPs prediction. The method achieved an overall accuracy of 84.5% and the area under the ROC curve (AUC) of 0.822 by Jackknife test, when the optimal subset included 10 features. Furthermore, on the same dataset, we compared our predictor with other existing methods, including R-score-based method and D-score-based methods, and the result of our method was superior to those of the two methods. The satisfactory performance suggests that our method is effective in predicting the deleterious nsSNPs in signal peptides. PMID:22277674

  2. Effects of air pollution on biogenic volatiles and ecological interactions

    Microsoft Academic Search

    Quinn S. McFrederick; Jose D. Fuentes; T’ai Roulston; James C. Kathilankal; Manuel Lerdau

    2009-01-01

    Chemical signals play important roles in ecological interactions but are vulnerable to perturbation by air pollution. In polluted\\u000a air masses, signals may travel shorter distances before being destroyed by chemical reactions with pollutants, thus losing\\u000a their specificity. To determine which scent-mediated interactions are likely to be affected, we review existing literature\\u000a to build a picture of what chemicals are commonly

  3. International Association for Ecology Genetic and Environmental Effects on Wing Polymorphisms in Two Tropical Earwigs

    E-print Network

    Bermingham, Eldredge

    of wing polymorphisms depends on knowledge of the adaptive values of the differ- ent morphs (AndersonInternational Association for Ecology Genetic and Environmental Effects on Wing Polymorphisms:253-255 (JCCOlOglU ? Springer-Verlag 1987 Genetic and environmental effects on wing polymorphisms in two tropical

  4. Effects of nitrogen fertiliser and pesticide management on floodwater ecology in a wetland ricefield

    Microsoft Academic Search

    Ian C. Simpson; Pierre A. Roger; Roberto Oficial; Ian F. Grant

    1994-01-01

    We investigated the effects of N fertiliser and pesticide applications on the population dynamics of benthic molluscs in a tropical wetland rice field. Populations were monitored for two consecutive dry seasons in selected treatments during a study on the effects of agricultural practices on the floodwater ecology of tropical rice fields. The most abundant species recorded in the ricefields were

  5. POPULATION ECOLOGY CO2 and O3 Effects on Paper Birch (Betulaceae: Betula papyrifera)

    E-print Network

    POPULATION ECOLOGY CO2 and O3 Effects on Paper Birch (Betulaceae: Betula papyrifera) Phytochemistry performance. KEY WORDS Betula papyrifera, Orgyia leucostigma whitemarked tussock moth, CO2, Aspen- FACE, O3 investigated the independent and interactive effects of CO2 and O3 on foliar quality of paper birch (Betula

  6. Journal of Applied Ecology (1987) 24, 63-73 EFFECTS OF FELINE PANLEUCOPAENIA ON THE

    E-print Network

    Pretoria, University of

    1987-01-01

    Journal of Applied Ecology (1987) 24, 63-73 EFFECTS OF FELINE PANLEUCOPAENIA ON THE POPULATIONTect the cat population but is no longer spreading effectively. FPL was independent of feline herpes (FVR the susceptible and isolated population ofcats, feline parvo virus was introduced during 1977 in an attempt

  7. Ecological effects of atmospheric releases from synthetic fuels processes. [Phytotoxicity of selected gas-stream emissions

    Microsoft Academic Search

    J. H. Shinn; J. R. Kercher

    1978-01-01

    The primary ecological effects of exposure to synthetic fuels gas-stream emissions are discussed. The primary impacts will be on vegetation due to a combination of phytotoxic gases. Little is known about the effects of potential trace gas emissions such as COS, CSâ, hydrocarbons, and volatile metals, but the most important phytoactive gases are COâ and HâS. With the aid of

  8. Applied Soil Ecology 21 (2002) 3148 Effects of mulching and fertilization on soil nutrients, microbial

    E-print Network

    Michel Jr., Frederick C.

    2002-01-01

    Applied Soil Ecology 21 (2002) 31­48 Effects of mulching and fertilization on soil nutrients, and improve plant health. However, little is known about how mulches affect soil or rhizosphere microbial effects on organic matter content, soil respiration, microbial biomass N, soil pH, cation

  9. 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...

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

    E-print Network

    Wisenden, Brian D.

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

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

    PubMed

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

    2013-06-01

    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

  12. Profiling deleterious non-synonymous SNPs of smoker's gene CYP1A1.

    PubMed

    Ramesh, A Sai; Khan, Imran; Farhan, Md; Thiagarajan, Padma

    2013-01-01

    CYP1A1 gene belongs to the cytochrome P450 family and is known better as smokers' gene due to its hyperactivation as a consequence of long term smoking. The expression of CYP1A1 induces polycyclic aromatic hydrocarbon production in the lungs, which when over expressed, is known to cause smoking related diseases, such as cardiovascular pathologies, cancer, and diabetes. Single nucleotide polymorphisms (SNPs) are the simplest form of genetic variations that occur at a higher frequency, and are denoted as synonymous and non-synonymous SNPs on the basis of their effects on the amino acids. This study adopts a systematic in silico approach to predict the deleterious SNPs that are associated with disease conditions. It is inferred that four SNPs are highly deleterious, among which the SNP with rs17861094 is commonly predicted to be harmful by all tools. Hydrophobic (isoleucine) to hydrophilic (serine) amino acid variation was observed in the candidate gene. Hence, this investigation aims to characterize a candidate gene from 159 SNPs of CYP1A1. PMID:23733671

  13. 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...

  14. A microcosm approach for evaluating the effects of the fungicides benomyl and captan on soil ecological processes and plant growth

    Microsoft Academic Search

    Shu-Kang Chen; Clive A. Edwards; Scott Subler

    2001-01-01

    The effects of benomyl and captan on soil ecological processes were tested in integrated terrestrial microcosms containing agricultural soil, organic amendments and wheat seedlings. The effects of the two fungicides on important soil ecological processes were evaluated by measuring soil microbial activity and biomass, including soil substrate-induced respiration (SIR), soil enzyme activity (dehydrogenase, urease and acid phosphatase) and microbial biomass

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

    E-print Network

    Schweik, Charles M.

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

  16. 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

  17. [Effects of land use structure change on regional ecological health--taking Shapingba County as an example].

    PubMed

    Wang, Cheng; Wei, Chaofu; Gao, Ming; Luo, Guanglian; Jiang, Wei

    2005-12-01

    Land resource is the carrier for the exchange of matter, energy and information flows, while the change velocity and the intensity of land use has strong effects on the ecological processes such as matter circulation, energy flow, and biologic diversity. Land use structure change will alter the type, area, and spatial distribution of ecosystem, and in the meantime, result in the changes of regional ecological health. Employing the principles and methods of landscape ecology, and through endowing relative ecological value to land use type, this paper analyzed the charaeteristics of recent 10 years land use change in Shapingba County of Chongqing, and discussed the effects of land use change on regional ecological health, aimed to provide scientific references for land use planning and sustainable land resource utilization. The results indicated that transformation often occurred among different land use types, and the land use structure in each transformation phase differed quite obviously. Under different land use structure, there was a great disparity in relative ecological value of sub-ecosystems, which played various roles in regional ecological health. In general, the regional relative ecological value embodied both increase and decrease. In the future, the relative ecological value of sub-ecosystem would represent three tendencies, i.e., increase first and decrease then, continuous decrease, and continuous increase. The situation of regional ecological health would gradually become better. PMID:16515175

  18. POPULATION ECOLOGY Environmentally Based Maternal Effects on Development Time in the

    E-print Network

    Savalli, Udo M.

    in response to food stress (e.g., Fox et al. 1996, Fox and Savalli 1998). Phenotypic plasticity in body sizePOPULATION ECOLOGY Environmentally Based Maternal Effects on Development Time in the Seed Beetle) reared at high density ( 20 eggs per seed) matured at a substantially smaller adult body size than

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

    Microsoft Academic Search

    Julio A. Camargo; Álvaro Alonso

    2006-01-01

    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

  20. Original Article The effect of ecological harshness on perceptions of the ideal female body size

    E-print Network

    Cooper, Brenton G.

    Original Article The effect of ecological harshness on perceptions of the ideal female body size Keywords: Life history theory Mortality Socioeconomic differences Body fat Pubertal timing Ideal body size of female body weight ideals? The current research uses insights from life history theory and female

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

    E-print Network

    Jackson, Don

    Micropterus salmoides and smallmouth bass M. dolomieu are two widely introduced species of fish prized environments, angling for bass, in particular largemouth bass Micropterus salmoides and smallmouth bass M1 Ecological Effects of Micropterus Introductions: the Dark Side of Black Bass DONALD A. JACKSON

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

    E-print Network

    Wu, Jianguo "Jingle"

    2002-01-01

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

  3. Ecological effects of PDMS-augmented sludge amended to agricultural microcosms

    Microsoft Academic Search

    D. A. Tolle; C. L. Frye; R. G. Lehmann; T. C. Zwick

    1995-01-01

    The potential ecological effects of polydimethylsiloxane (PDMS)-augmented sewage sludge resulting from use of the sludge as an agricultural amendment were evaluated in a preliminary pot test and a definitive test in intact, agricultural soil-core microcosms. Seed germination and early seedling survival were evaluated in the pot study. The parameters investigated in microcosms included soil microorganism populations, crop productivity, and nutrient

  4. ECOLOGY AND POPULATION BIOLOGY Effects of Aggregation Size and Host Plant on the Survival of an

    E-print Network

    Campbell, Diane

    ECOLOGY AND POPULATION BIOLOGY Effects of Aggregation Size and Host Plant on the Survival of an Ant-Tended Membracid (Hemiptera: Membracidae): Potential Roles in Selecting for Generalized Host Plant Use JENNIFER S in host plant use from specialists to extreme generalists. Potential factors that may inßuence relative

  5. DETECTING THE ECOLOGICAL EFFECTS OF ENVIRONMENTAL IMPACTS: A CASE STUDY OF KELP FOREST INVERTEBRATES

    Microsoft Academic Search

    Absfrucr. Detecting the environmental impacts of human activities on natural communities is a central problem in applied ecology. It is a difficult problem because one must separate human perturbations from the considerable natural temporal variability displayed by most populations. In addition, most human perturbations are generally unique and thus unreplicated. This raises the problem of deciding whether observed local effects

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

    E-print Network

    Fagherazzi, Sergio

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

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

    E-print Network

    Nacional de San Luis, Universidad

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

  8. 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...

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

    E-print Network

    Bronikowski, Anne

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

  10. POPULATION ECOLOGY Landscape context outweighs local habitat quality in its effects on

    E-print Network

    Cronin, James T.

    POPULATION ECOLOGY Landscape context outweighs local habitat quality in its effects on herbivore quality), patch geometry (e.g., patch size and isolation), and more recently land- scape context (e- tions on previously vacant patches and to sustain populations in sink habitats. Most studies

  11. COMMUNITY ECOLOGY -ORIGINAL PAPER Differential effects of habitat isolation and landscape composition

    E-print Network

    Richner, Heinz

    COMMUNITY ECOLOGY - ORIGINAL PAPER Differential effects of habitat isolation and landscape in the landscape and three levels of isolation from the next woody habitat (patch isolation) on trap nesting bees was negatively affected by patch isolation and positively affected by the amount of woody habitat

  12. The ecological effects of naphthenic acids and salts on phytoplankton from the Athabasca oil sands region

    Microsoft Academic Search

    Sherwin S. Leung; Mike D. MacKinnon; Ralph E. H. Smith

    2003-01-01

    To better elucidate the ecological effects of naphthenic acids and major ions liberated in oil sands development, the summer-time composition of phytoplankton communities in ten water bodies near Fort McMurray (northeastern Alberta) was studied in 1997. The water bodies varied in degree of process water influence, and in age, size and ancillary chemical characteristics. Community biomass of phytoplankton was not

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

    E-print Network

    Harrison, Susan

    Ecological contingency in the effects of climatic warming on forest herb communities Susan change in understory herb communities over a 60-y period (1949/1951­2007/ 2009) in a complex montane,500­2,100 m above sea level). In lower montane forests, regardless of land-use history, we found multiple herb

  14. ECOSYSTEM ECOLOGY -ORIGINAL PAPER Pacific salmon effects on stream ecosystems: a quantitative

    E-print Network

    Tiegs, Scott

    ECOSYSTEM ECOLOGY - ORIGINAL PAPER Pacific salmon effects on stream ecosystems: a quantitative during their annual spawning runs, leading researchers to classify these fish as ecosystem engineers-analysis to evaluate potential sources of variability among studies in stream ecosystem responses to salmon. Results

  15. 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...

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

    E-print Network

    Reynolds, John D.

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

  17. Ecological effects of urban stormwater runoff on benthic macroinvertebrates inhabiting the Green River, Massachusetts

    Microsoft Academic Search

    Joel M. Pratt; Robert A. Coler; Paul J. Godfrey

    1981-01-01

    Although it has been demonstrated that urban stormwater can alter the quality of receiving waters, the corresponding impact on aquatic biota remains essentially undocumented. A year-long intensive study, therefore, was implemented to monitor and describe the ecological effects exerted by urban runoff on benthic macroinvertebrates.

  18. Fermented liquid feed and fermented grain to piglets effect on gastrointestinal ecology and growth performance

    Microsoft Academic Search

    N. Canibe; B. B. Jensen

    2007-01-01

    A study was carried out to determine the microbial and nutritional characteristics of dry feed, liquid feed containing fermented liquid cereal grain, and fermented liquid compound feed, and their effect on gastrointestinal ecology and growth performance of piglets. Three dietary treatments were designed: dry feed (DRY); fermented liquid cereal grain feed (FLG); and fermented liquid feed (FLF). The FLF was

  19. ECOSYSTEM ECOLOGY The effects of tree rhizodeposition on soil exoenzyme activity,

    E-print Network

    Schmidt, Steven K.

    ECOSYSTEM ECOLOGY The effects of tree rhizodeposition on soil exoenzyme activity, dissolved organic), and microbial biomass C and N. We found that rhi- zodeposition is high in the spring, when the soils are still, and organic phosphorus are not affected by springtime increases in soil microbial biomass associated

  20. Ecological Engineering 25 (2005) 153167 Lessons learned: An assessment of the effectiveness of a National

    E-print Network

    2005-01-01

    Ecological Engineering 25 (2005) 153­167 Lessons learned: An assessment of the effectiveness lessons learned about the function of a national review Committee (National Technical Review Committee of the Mississippi Delta). Lessons learned are based on responses to five questions to the NTRC. What was the best

  1. Design and analysis of experiments testing for biodiversity effects in ecology

    E-print Network

    Design and analysis of experiments testing for biodiversity effects in ecology R. A. Baileya is that a nested family of plausible models is fitted. The results of three experiments suggest that biodiversity are discussed. Keywords: Biodiversity, Design of experiments, Family of models, Hasse diagram 2008 MSC: 62K99

  2. 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…

  3. POPULATION ECOLOGY -ORIGINAL PAPER The effects of sex, age and breeding success on breeding dispersal

    E-print Network

    Laaksonen, Toni

    POPULATION ECOLOGY - ORIGINAL PAPER The effects of sex, age and breeding success on breeding-Verlag 2008 Abstract We modelled breeding dispersal of an insec- tivorous bird, the pied flycatcher (Ficedula, breeding success and environmental pollution on breeding dispersal distances of F. hypoleuca females

  4. The effects of different gender harvesting practices on mangrove ecology and conservation in Cameroon

    Microsoft Academic Search

    Njisuh Z. Feka; Mario G. Manzano; Farid Dahdouh-Guebas

    2011-01-01

    Wood harvesting is an important source of income and a direct threat to mangrove forests in West-Central Africa. To understand the effects of this activity on mangrove ecology, it is necessary to assess harvesting practices of local communities. Knowledge on those is scarce for this region; we therefore examined implications of gender roles on the sustainability of mangrove forests in

  5. Impact: toward a framework for understanding the ecological effects of invaders

    Microsoft Academic Search

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

    1999-01-01

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

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

    E-print Network

    Losos, Jonathan B.

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

  7. Ecological Modelling 171 (2004) 2133 Bottom-up and top-down effects in food chains

    E-print Network

    Vermont, University of

    2004-01-01

    Ecological Modelling 171 (2004) 21­33 Bottom-up and top-down effects in food chains depend analysis of trophic-level interactions within the standard energy-based linear food-chain model, or (2) 21­33 Section 3: General analytical approach for a press-perturbed food chain. Section 4: Response

  8. Computational analyses and prediction of guanylin deleterious SNPs.

    PubMed

    Porto, William F; Franco, Octávio L; Alencar, Sérgio A

    2015-07-01

    Human guanylin, coded by the GUCA2A gene, is a member of a peptide family that activates intestinal membrane guanylate cyclase, regulating electrolyte and water transport in intestinal and renal epithelia. Deregulation of guanylin peptide activity has been associated with colon adenocarcinoma, adenoma and intestinal polyps. Besides, it is known that mutations on guanylin receptors could be involved in meconium ileus. However, there are no previous works regarding the alterations driven by single nucleotide polymorphisms in guanylin peptides. A comprehensive in silico analysis of missense SNPs present in the GUCA2A gene was performed taking into account 16 prediction tools in order to select the deleterious variations for further evaluation by molecular dynamics simulations (50ns). Molecular dynamics data suggest that the three out of five variants (Cys104Arg, Cys112Ser and Cys115Tyr) have undergone structural modifications in terms of flexibility, volume and/or solvation. In addition, two nonsense SNPs were identified, both preventing the formation of disulfide bonds and resulting in the synthesis of truncated proteins. In summary the structural analysis of missense SNPs is important to decrease the number of potential mutations to be in vitro evaluated for associating them with some genetic diseases. In addition, data reported here could lead to a better understanding of structural and functional aspects of guanylin peptides. PMID:25899674

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

    E-print Network

    Keightley, Peter

    by scanning 20 million bases of DNA from three sets of mutation accumulation lines by using denaturing high and become fixed at random. However, this method will underestimate U because many deleterious mutationsLETTERS Direct estimation of per nucleotide and genomic deleterious mutation rates in Drosophila

  10. Antagonistic coevolution with parasites increases the cost of host deleterious mutations

    E-print Network

    Buckling, Angus

    Antagonistic coevolution with parasites increases the cost of host deleterious mutations Angus. The significance of host deleterious mutations when hosts and parasites antagonistically coevolve (reciprocal is by definition costly to hosts, but may sometimes provide benefits. For example, parasites that have already

  11. 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

  12. The Cummulative Ecological Effects of Normal Offshore Petroleum Operations Contrasted With Those Resulting From Continental Shelf Oil Spills

    Microsoft Academic Search

    J. M. Sharp; S. G. Appan

    1982-01-01

    Assessments of the cumulative ecological effects of chronic sublethal discharges from normal (non-spill) offshore petroleum operations have been based on (1) model studies, (2) controlled laboratory and microcosm experiments, (3) studies of spills of crude oil and its refined products and of severe organic pollution, and (4) ecological field studies in areas of intensive petroleum operations. Methods (2) and (3)

  13. CUMULATIVE ECOLOGICAL AND SOCIOECONOMIC EFFECTS OF FOREST POLICIES IN COASTAL OREGON

    Microsoft Academic Search

    Thomas A. Spies; K. Norman Johnson; Kelly M. Burnett; Janet L. Ohmann; Brenda C. McComb; Gordon H. Reeves; Pete Bettinger; Jeffrey D. Kline; Brian Garber-Yonts

    2007-01-01

    Forest biodiversity policies in multi-ownership landscapes are typically developed in an uncoordinated fashion with little consideration of their interactions or possible unintended cumulative effects. We conducted an assessment of some of the ecological and socioeconomic effects of recently enacted forest management policies in the 2.3-million-ha Coast Range Physiographic Province of Oregon. This mountainous area of conifer and hardwood forests includes

  14. Warfare Ecology

    NSDL National Science Digital Library

    Gary E. Machlis (University of Idaho; )

    2008-09-01

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

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

    PubMed Central

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

    2003-01-01

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

  16. Computational identification and structural analysis of deleterious functional SNPs in MLL gene causing acute leukemia.

    PubMed

    George Priya Doss, C; Rajasekaran, R; Sethumadhavan, Rao

    2010-09-01

    A promising application of the huge amounts of data from the Human Genome Project currently available offers new opportunities for identifying the genetic predisposition and developing a better understanding of complex diseases such as cancers. The main focus of cancer genetics is the study of mutations that are causally implicated in tumorigenesis. The identification of such causal mutations does not only provide insight into cancer biology but also presents anticancer therapeutic targets and diagnostic markers. In this study, we evaluated the Single Nucleotide Polymorphisms (SNPs) that can alter the expression and the function in MLL gene through computational methods. We applied an evolutionary perspective to screen the SNPs using a sequence homologybased SIFT tool, suggested that 10 non-synonymous SNPs (nsSNPs) (50%) were found to be deleterious. Structure based approach PolyPhen server suggested that 5 nsSNPS (25%) may disrupt protein function and structure. PupaSuite tool predicted the phenotypic effect of SNPs on the structure and function of the affected protein. Structure analysis was carried out with the major mutations that occurred in the native protein coded by MLL gene is at amino acid positions Q1198P and K1203Q. The solvent accessibility results showed that 7 residues changed from exposed state in the native type protein to buried state in Q1198P mutant protein and remained unchanged in the case of K1203Q. From the overall results obtained, nsSNP with id (rs1784246) at the amino acid position Q1198P could be considered as deleterious mutation in the acute leukemia caused by MLL gene. PMID:20658337

  17. Theoretically exploring direct and indirect chemical effects across ecological and exposure scenarios using mechanistic fate and effects modelling.

    PubMed

    De Laender, F; Morselli, M; Baveco, H; Van den Brink, P J; Di Guardo, A

    2015-01-01

    Predicting ecosystem response to chemicals is a complex problem in ecotoxicology and a challenge for risk assessors. The variables potentially influencing chemical fate and exposure define the exposure scenario while the variables determining effects at the ecosystem level define the ecological scenario. In absence of any empirical data, the objective of this paper is to present simulations by a fugacity-based fate model and a differential equation-based ecosystem model to theoretically explore how direct and indirect effects on invertebrate shallow pond communities vary with changing ecological and exposure scenarios. These simulations suggest that direct and indirect effects are larger in mesotrophic systems than in oligotrophic systems. In both trophic states, interaction strength (quantified using grazing rates) was suggested a more important driver for the size and recovery from direct and indirect effects than immigration rate. In general, weak interactions led to smaller direct and indirect effects. For chemicals targeting mesozooplankton only, indirect effects were common in (simple) food-chains but rare in (complex) food-webs. For chemicals directly affecting microzooplankton, the dominant zooplankton group in the modelled community, indirect effects occurred both in food-chains and food-webs. We conclude that the choice of the ecological and exposure scenarios in ecotoxicological modelling efforts needs to be justified because of its influence on the prevalence and magnitude of the predicted effects. Overall, more work needs to be done to empirically test the theoretical expectations formulated here. PMID:25454235

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

    PubMed Central

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

    2013-01-01

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

  19. 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.

  20. 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.

  1. Experimental Study on the Effect of Habitat Isolation on River Ecology

    Microsoft Academic Search

    Xuehua Duan; Zhaoyin Wang

    \\u000a Field investigations and an experiment were conducted in the Juma River, in the suburbs of Beijing, to study the effect of\\u000a habitat fragmentation on river ecology using benthic macroinvertebrates as indicator species. Three experimental plots were\\u000a isolated from a relatively undisturbed stream habitat with sheet iron. Benthic assemblages were measured by sampling periodically.\\u000a The results indicate that the abundance, taxa

  2. 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...

  3. 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,…

  4. ECOLOGICAL EFFECTS OF PESTICIDES ON NON-TARGET SPECIES

    EPA Science Inventory

    This report was done in 1971 when there was no single source of data on the environmental effects of pesticides. It is a comprehensive compilation of published data. The judgments on what to include and what not to include are those of the author, though many individuals in the F...

  5. ECOLOGICAL EFFECTS OF EXPERIMENTAL ACIDIFICATION ON A STREAM ECOSYSTEM

    EPA Science Inventory

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

  6. Deleterious mutations can surf to high densities on the wave front of an expanding population.

    PubMed

    Travis, Justin M J; Münkemüller, Tamara; Burton, Olivia J; Best, Alex; Dytham, Calvin; Johst, Karin

    2007-10-01

    There is an increasing recognition that evolutionary processes play a key role in determining the dynamics of range expansion. Recent work demonstrates that neutral mutations arising near the edge of a range expansion sometimes surf on the expanding front leading them rather than that leads to reach much greater spatial distribution and frequency than expected in stationary populations. Here, we extend this work and examine the surfing behavior of nonneutral mutations. Using an individual-based coupled-map lattice model, we confirm that, regardless of its fitness effects, the probability of survival of a new mutation depends strongly upon where it arises in relation to the expanding wave front. We demonstrate that the surfing effect can lead to deleterious mutations reaching high densities at an expanding front, even when they have substantial negative effects on fitness. Additionally, we highlight that this surfing phenomenon can occur for mutations that impact reproductive rate (i.e., number of offspring produced) as well as mutations that modify juvenile competitive ability. We suggest that these effects are likely to have important consequences for rates of spread and the evolution of spatially expanding populations. PMID:17703053

  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. Effects of noise on some dynamical models in ecology.

    PubMed

    Schaffer, W M; Ellner, S; Kot, M

    1986-01-01

    We investigate effects of random perturbations on the dynamics of one-dimensional maps (single species difference equations) and of finite dimensional flows (differential equations for n species). In particular, we study the effects of noise on the invariant measure, on the "correlation" dimension of the attractor, and on the possibility of detecting the nonlinear deterministic component by applying reconstruction techniques to the time series of population abundances. We conclude that adding noise to maps with a stable fixed-point obscures the underlying determinism. This turns out not to be the case for systems exhibiting complex periodic or chaotic motion, whose essential properties are more robust. In some cases, adding noise reveals deterministic structure which otherwise could not be observed. Simulations suggest that similar results hold for flows whose attractor is almost two-dimensional. PMID:3805908

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

    Microsoft Academic Search

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

    1998-01-01

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

  10. SySAP: a system-level predictor of deleterious single amino acid polymorphisms.

    PubMed

    Huang, Tao; Wang, Chuan; Zhang, Guoqing; Xie, Lu; Li, Yixue

    2012-01-01

    Single amino acid polymorphisms (SAPs), also known as non-synonymous single nucleotide polymorphisms (nsSNPs), are responsible for most of human genetic diseases. Discriminate the deleterious SAPs from neutral ones can help identify the disease genes and understand the mechanism of diseases. In this work, a method of deleterious SAP prediction at system level was established. Unlike most existing methods, our method not only considers the sequence and structure information, but also the network information. The integration of network information can improve the performance of deleterious SAP prediction. To make our method available to the public, we developed SySAP (a System-level predictor of deleterious Single Amino acid Polymorphisms), an easy-to-use and high accurate web server. SySAP is freely available at http://www.biosino.org/ SySAP/ and http://lifecenter.sgst.cn/SySAP/. PMID:22183811

  11. High Deleterious Genomic Mutation Rate in Stationary Phase of Escherichia coli 

    E-print Network

    Loewe, Laurence; Textor, Volker; Scherer, Siegfried

    2003-01-01

    In natural habitats, bacteria spend most of their time in some form of growth arrest. Little is known about deleterious mutations in such stages, and consequently there is limited understanding of what evolutionary events ...

  12. 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.

  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. 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

  15. [Effect of ecological organic fertilizer on tomato bacterial wilt and soil microbial diversities].

    PubMed

    Cai, Yanfei; Liao, Zongwen; Zhang, Jia'en; Kong, Weidong; He, Chengxin

    2003-03-01

    The effects of ecological organic fertilizer (EOF) on tomato bacterial wilt and soil microbial community were studied through field trial and fatty acid methyl esters (FAMEs) analysis. The results showed that the incidence rate of tomato bacterial wilt was 100% in continuous cropped soil, and significantly reduced to 39% and 50% when applying EOF at 1.0 kg.m-2 and 0.5 kg.m-2, respectively. There was no significant difference between two fertilization treatments. The fatty acid fingerprints of soil microbial community were greatly changed, and the relative contents of cyc17:0 cited as biomarker for GN bacteria, c18:2 w6 as biomarker for fungi and c16:1 11c as biomarker for arbuscular mycorrhizal (AM) fungi all increased when applying EOF. The minimum distance of cluster analysis was 1.08 between control and treatments of applying ecological organic fertilizer, and 0.70 between different fertilization treatments. Applying EOF could adjust soil microbial community structure, benefit for soil beneficial microbes, and develop stability and disease suppression of soil ecological system, and hence, improve soil quality. PMID:12836539

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

    PubMed

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

    2009-08-01

    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

  17. Long-Term Low Carbohydrate Diet Leads to Deleterious Metabolic Manifestations in Diabetic Mice

    PubMed Central

    Handa, Keiko; Inukai, Kouichi; Onuma, Hirohisa; Kudo, Akihiko; Nakagawa, Fumiyuki; Tsugawa, Kazue; Kitahara, Atsuko; Moriya, Rie; Takahashi, Kazuto; Sumitani, Yoshikazu; Hosaka, Toshio; Kawakami, Hayato; Oyadomari, Seiichi; Ishida, Hitoshi

    2014-01-01

    We investigated long-term effects of low carbohydrate diets on wild type mice, streptozotocin-injected and KKAy obese diabetic mice. These mice were pair-fed three different types of diets, standard chow (SC, C?P?F?=?63?15?22), a low carbohydrate (LC, C?P?F?=?38?25?37) diet and a severely carbohydrate restricted (SR, C?P?F?=?18?45?37) diet for 16 weeks. Despite comparable body weights and serum lipid profiles, wild type and diabetic mice fed the low carbohydrate diets exhibited lower insulin sensitivity and this reduction was dependent on the amount of carbohydrate in the diet. When serum fatty acid compositions were investigated, monounsaturation capacity, i.e. C16:1/C16:0 and C18:1/C18:0, was impaired in all murine models fed the low carbohydrate diets, consistent with the decreased expression of hepatic stearoyl-CoA desaturase-1 (SCD1). Interestingly, both the hepatic expressions and serum levels of fibroblast growth factor 21 (FGF21), which might be related to longevity, were markedly decreased in both wild type and KKAy mice fed the SR diet. Taking into consideration that fat compositions did not differ between the LC and SR diets, we conclude that low carbohydrate diets have deleterious metabolic effects in both wild type and diabetic mice, which may explain the association between diets relatively low in carbohydrate and the elevated risk of cardiovascular events observed in clinical studies. PMID:25170869

  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. Ecological Applications, Scott V. Ollinger et al. Ozone Effects on Forest Productivity 7(4), 1997, pp. 1237-1251

    E-print Network

    New Hampshire, University of

    . Interannual variation in predicted ozone effects was small due to concurrent fluctuations in ozone and climateEcological Applications, Scott V. Ollinger et al. Ozone Effects on Forest Productivity 7(4), 1997, pp. 1237-1251 1 SIMULATING OZONE EFFECTS ON FOREST PRODUCTIVITY: INTERACTIONS AMONG LEAF-, CANOPY

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

    E-print Network

    Garrett, Karen A.

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

  2. Exploration of deleterious single nucleotide polymorphisms in late-onset Alzheimer disease susceptibility genes.

    PubMed

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

    2013-01-10

    Non-synonymous single nucleotide polymorphisms (nsSNPs) are considered as biomarkers to disease susceptibility. In the present study, nsSNPs in CLU, PICALM and BIN1 genes were screened for their functional impact on concerned proteins and their plausible role in Alzheimer disease (AD) susceptibility. Initially, SNPs were retrieved from dbSNP database, followed by identification of potentially deleterious nsSNPs and prediction of their effect on proteins by PolyPhen and SIFT. Protein stability and the probability of mutation occurrence were predicted using I-Mutant and PANTHER respectively. SNPs3D and FASTSNP were used for the functional analysis of nsSNPs. The functional impact on the 3D structure of proteins was evaluated by SWISSPDB viewer and NOMAD-Ref server. On analysis, 3 nsSNPs with IDs rs12800974 (T158P) of PICALM and rs11554585 (R397C) and rs11554585 (N106D) of BIN1 were predicted to be functionally significant with higher scores of I-Mutant, SIFT, PolyPhen, PANTHER, FASTSNP and SNPs3D. The mutant models of these nsSNPs also showed very high energies and RMSD values compared to their native structures. Current study proposes that the three nsSNPs identified in this study constitute a unique resource of potential genetic factors for AD susceptibility. PMID:22960267

  3. 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

  4. Ecology 2005 19, 699706

    E-print Network

    Traveset, Anna

    vegetation, ornithocory, saurochory, seed emergence rate Functional Ecology (2005) 19, 699­706 doi: 10.1111/jFunctional Ecology 2005 19, 699­706 © 2005 British Ecological Society 699 -Blackwell Publishing, Ltd. Effect of seed passage through birds and lizards on emergence rate of mediterranean species

  5. 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

  6. Possible deleterious hormonal changes associated with low-sodium diets.

    PubMed

    Clark, Jaime L; Rech, Leslie; Chaity, Nazia; Sihag, Jyoti; Taylor, Carla G; Aliani, Michel

    2015-01-01

    The average salt intake of people in Canada, the United States, and Europe is about 3,400 mg of sodium per day, which exceeds the recommended intake levels set by various health organizations. The World Health Organization recommends a worldwide reduction of sodium intake to less than 2,000 mg per day. Most research to date has focused on the negative effects of high-sodium intake; however, little information is available on the metabolic effects of low-sodium intakes. This review focuses on the hormonal changes associated with low-sodium diets, especially the hormones involved in metabolism and cardiovascular and renal function. Based largely on rodent studies, low-sodium diets have been associated with changes in glycemic control, energy metabolism, cardiovascular disease risk, cholesterol concentrations, inflammation, and functioning of the renin-angiotensin-aldosterone system. Overall, research has revealed mixed results regarding the impact of dietary sodium intake on various hormones. Further research is required to assess the effects of sodium reduction on hormones and their associated pathways in order to determine the likelihood of any unintended effects. PMID:26024055

  7. 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.

  8. Fire Ecology

    NSDL National Science Digital Library

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

  9. 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.

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

    E-print Network

    Kratochvíl, Lukas

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

  11. Effects of ionizing radiation upon natural populations and ecosystems. Final report. [Ecological perspectives in land use planning

    Microsoft Academic Search

    1976-01-01

    Accomplishments throughout a 10-year period summarized include: a study of the effects of radiation from a ..gamma.. source on the ecology of the El Verde rain forest in Puerto Rico, with emphasis on the role of secondary succession in the recovery of forest ecosystems following irradiation; the effects of light and temperature on gaseous exchange in trees using ¹CO as

  12. 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 ...

  13. 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.

  14. Raising highly desirable lipoprotein versus lowering deleterious lipoprotein.

    PubMed

    Cheung, Bernard My; Kumana, Cyrus R

    2010-03-01

    Evaluation of: Taylor AJ, Villines TC, Stanek EJ et al. Extended-release niacin or ezetimibe and carotid intima-media thickness. N. Engl. J. Med. 361(22), 2113-2122 (2009). Epidemiological evidence suggests that elevated low-density lipoprotein cholesterol (LDL-C) and reduced high-density lipoprotein cholesterol (HDL-C) are both factors causing coronary heart disease. These authors compared extended-release niacin, which raises HDL-C, with ezetimibe, which lowers LDL-C, in a study named Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies (ARBITER 6-HALTS). The study was terminated early and only 208 patients were included in the analysis. Ezetimibe decreased LDL-C by 19.2%, to 66 mg/dl (1.7 mmol/l), whereas niacin increased HDL-C by 18.4%. Ezetimibe did not reduce carotid intima-media thickness, whereas niacin decreased it significantly. Moreover, major adverse cardiovascular events occurred in 5% of the ezetimibe group but only 1% of the niacin group (p = 0.04). The study suggests that niacin may be more effective than ezetimibe as an adjunct to statin in regressing atherosclerosis and in preventing cardiovascular events. This small study of short duration reported a very large treatment effect, so the findings need to be confirmed in a larger longer trial. Nevertheless, it provides the evidence that we now have an additional class of drugs besides statins that can reduce atherosclerosis and cardiovascular events. PMID:22111565

  15. 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)

  16. 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 test–retest 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 learn–test 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

  17. Face adaptation effects show strong and long-lasting transfer from lab to more ecological contexts.

    PubMed

    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 test-retest 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 learn-test 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

  18. 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

  19. 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

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

    PubMed

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

    2014-11-19

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

  1. 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.

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

    E-print Network

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

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

    E-print Network

    West, Stuart

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

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

    Microsoft Academic Search

    ALEXEY S. KONDRASHOV

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

  5. Ecology 2001 15, 772781

    E-print Network

    Janzen, Fredric

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

  6. 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

  7. Selective pressures at a codon-level predict deleterious mutations in human disease genes.

    PubMed

    Arbiza, Leonardo; Duchi, Serena; Montaner, David; Burguet, Jordi; Pantoja-Uceda, David; Pineda-Lucena, Antonio; Dopazo, Joaquín; Dopazo, Hernán

    2006-05-19

    Deleterious mutations affecting biological function of proteins are constantly being rejected by purifying selection from the gene pool. The non-synonymous/synonymous substitution rate ratio (omega) is a measure of selective pressure on amino acid replacement mutations for protein-coding genes. Different methods have been developed in order to predict non-synonymous changes affecting gene function. However, none has considered the estimation of selective constraints acting on protein residues. Here, we have used codon-based maximum likelihood models in order to estimate the selective pressures on the individual amino acid residues of a well-known model protein: p53. We demonstrate that the number of residues under strong purifying selection in p53 is much higher than those that are strictly conserved during the evolution of the species. In agreement with theoretical expectations, residues that have been noted to be of structural relevance, or in direct association with DNA, were among those showing the highest signals of purifying selection. Conversely, those changing according to a neutral, or nearly neutral mode of evolution, were observed to be irrelevant for protein function. Finally, using more than 40 human disease genes, we demonstrate that residues evolving under strong selective pressures (omega<0.1) are significantly associated (p<0.01) with human disease. We hypothesize that non-synonymous change on amino acids showing omega<0.1 will most likely affect protein function. The application of this evolutionary prediction at a genomic scale will provide an a priori hypothesis of the phenotypic effect of non-synonymous coding single nucleotide polymorphisms (SNPs) in the human genome. PMID:16584746

  8. 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).

  9. 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.

  10. Maximum power, ecological function and efficiency of an irreversible Carnot cycle. A cost and effectiveness optimization

    E-print Network

    Aragon-Gonzalez, G; Leon-Galicia, A; Morales-Gomez, J R

    2007-01-01

    In this work we include, for the Carnot cycle, irreversibilities of linear finite rate of heat transferences between the heat engine and its reservoirs, heat leak between the reservoirs and internal dissipations of the working fluid. A first optimization of the power output, the efficiency and ecological function of an irreversible Carnot cycle, with respect to: internal temperature ratio, time ratio for the heat exchange and the allocation ratio of the heat exchangers; is performed. For the second and third optimizations, the optimum values for the time ratio and internal temperature ratio are substituted into the equation of power and, then, the optimizations with respect to the cost and effectiveness ratio of the heat exchangers are performed. Finally, a criterion of partial optimization for the class of irreversible Carnot engines is herein presented.

  11. Transport, transformation and ecological effects of phosphorus smokes in an environmental wind tunnel

    SciTech Connect

    Van Voris, P.; Cataldo, D.A.; Garland, T.R.; Ligotke, M.W.; Rogers, J.E.; McFadden, K.M.; Carlile, D.W.; Li, S.W.

    1985-04-01

    An evaluation of the terrestrial transport, transformations and ecological effects of phosphorus (red phosphorus-butyl rubber (RP/BR)), smoke/obscurant was performed to characterize the effects on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of representative of soils of those sites; and (3) soil microbiological communities. The influence and interactions of smoke/obscurant concentration relative humidity and wind speed was assessed. Toxicity symptoms for plants from repeated or a single exposure included leaf tip burn, leaf curl, leaf abscission and drop, floral abortion, chlorosis, neucrotic spotting, wilting, dessication and dieback for ponderosa pine, short needle pine, sagebrush, a native grass (Blando Brome) and bushbean. Soils data suggest an increase in the mobility of selected trace elements after exposure; however, this effect appears to be ameliorated with time. This phenomenon is influenced by soil type, which is a reflection of the buffering capacity of the exposed soil (i.e., Burbank, Quallayute, Shawano, and Yamac) as well as the concentration and duration of exposure. Increased mobility of trace elements is also evidenced in the trace element content of plants grown on soils after exposure to RP/BR smoke. Soil Microbial Community effects show a reduction in the production of nitrate after soil is exposed to RP/BR smoke. This indicates a reduction in ammonium oxidizing bacterial populations, specifically Nitrosomonas and probably Nitrobacter. For the most part most of the plant, soil and soil microbial effects are transient.

  12. Does Parenting Mediate the Effects of Exposure to Violence on Violent Behavior? An Ecological-Transactional Model of Community Violence

    ERIC Educational Resources Information Center

    Spano, Richard; Vazsonyi, Alexander T.; Bolland, John

    2009-01-01

    Three waves of longitudinal data from a high poverty sample of 1544 African American youth were used to test an ecological-transactional model of violence. SEM analyses were conducted to determine whether parenting (Time 2) mediated the effects of exposure to violence (Time 1) on violent behaviors (Time 3). Findings supported the specified model.…

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

    Microsoft Academic Search

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

    2011-01-01

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

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

    EPA Science Inventory

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

  15. EcologicalEntomology (1989) 14,209-218 Effects of changing photoperiods in the life cycle regulation

    E-print Network

    Nylin, Sören

    1989-01-01

    EcologicalEntomology (1989) 14,209-218 Effects of changing photoperiods in the life cycle unclear (Tauber et al., 1986). From hibernation v i To hibernation FIG.1. The life cycle of Polygonia c regulation of the comma butterfly, Polygonia c-album (Nymphalidae) SOREN NYLIN Department of

  16. Similarity of microbial and meiofaunal community analyses for mapping ecological effects of heavy-metal contamination in soil

    Microsoft Academic Search

    Richard J. Ellis; J. George Best; John C. Fry; Philip Morgan; Barry Neish; Marcus W. Trett; Andrew J. Weightman

    2002-01-01

    The effect of long-term heavy-metal contamination on soil microbial and meiofaunal communities was assessed with a view to determining whether analysis of these communities could be used for ecological assessment of contaminated sites. Thirty soil cores were taken from an industrial site formerly used for the burning of waste from an explosives factory. The predominant contaminants in the soil were

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

    EPA Science Inventory

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

  18. Isotopes reveal limited effects of middle Pleistocene climate change on the ecology of mid-sized mammals

    E-print Network

    Paytan, Adina

    fossils from the Pit Locality of Porcupine Cave, to evaluate how two taxa responded to climatic events- ronment around Porcupine Cave during the middle Pleistocene, similar to what is present around the cave climatic change had a negligible effect on the ecology of the sampled individuals around Porcupine Cave

  19. Effect of feeding fermented liquid feed and fermented grain on gastrointestinal ecology and growth performance in piglets

    Microsoft Academic Search

    N. Canibe; O. Højberg; J. H. Badsberg; B. B. Jensen

    2010-01-01

    To investigate the microbial and nutri- tional characteristics of dry feed, liquid feed containing fermented liquid cereal grains, and fermented liquid feed, and their effect on gastrointestinal ecology and growth performance, 120 piglets from 40 litters were used and housed in pens with 5 animals in each. The 3 dietary treatments (all nonheated and nonpelleted diets) were: a dry meal

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

    Microsoft Academic Search

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

    1994-01-01

    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

  1. 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.

  2. Effects of light quality on the physiology and the ecology of planktonic green sulfur bacteria in lakes

    Microsoft Academic Search

    X. Vila; C. A. Abella

    1994-01-01

    The effect of light quality on the selection of natural populations of Green Sulfur Bacteria (Chlorobiaceae) is considered to be a classic factor in the determination of their ecological niches. From the comparison among phototrophic bacterial populations of lakes, it is shown that brown and green pigmented groups of Chlorobiaceae have a differential distribution depending on depth. Statistical analyses prove

  3. Effect of water, tillage and herbicide on ecology of weed communities in intensive wet-seeded rice system

    Microsoft Academic Search

    R. M. Bhager; S. I. Bhuiyan; K. Moody; L. E. Estorninos

    1999-01-01

    Quantitative information on shifts in weed flora brought about by changing soil and water management practices can provide valuable indications for future weed control strategies. This study designed to address quantitative effects on weed ecology as a result of changing water regime, tillage intensity and herbicide dose, was carried out on a farmers field in village Baluga, Talavera, Nueva Ecija,

  4. 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...

  5. Inclusion of soil arsenic bioaccessibility in ecological risk assessment and comparison with biological effects.

    PubMed

    Saunders, Jared R; Knopper, Loren D; Koch, Iris; Reimer, Kenneth J

    2011-12-15

    The purpose of this study was to conduct an ecological risk assessment (ERA) for meadow voles (Microtus pennslvanicus) found at three arsenic contaminated sites in Nova Scotia, Canada (as well as two background locations) and to compare the numeric results to measured biomarkers of exposure and effect. The daily intake of arsenic by meadow voles was determined by three separate calculations: estimated daily intake (EDI), bioaccessible estimated daily intake (BEDI, with bioaccessibility of soil included), and actual daily intake (ADI, which is calculated with arsenic concentrations in the stomach contents). The median bioaccessibility of arsenic in soils from the contaminated locations was significantly greater than at background locations. The bioaccessible arsenic concentration in soil from all samples (both contaminated and background) was significantly less than the total concentration. Use of site-specific bioaccessibility (hazard quotients=38 at Upper Seal Harbour (USH); 60 at Lower Seal Harbour (LSH); and 120 at Montague tailings (MONT)) and stomach arsenic contents (hazard quotients=2.1 at USH; 7.9 at LSH; and 6.7 at MONT) in the ERA resulted in lower numeric risk than compared to risk calculated with 100% bioavailability (hazard quotient=180 at USH; 75 at LSH; and 680 at MONT). Further, the use of bioaccessibility on the calculation of risk was aligned with biomarker results (changes in glutathione and micronucleated erythrocytes) in voles captured at the sites. This study provides evidence that using site-specific bioaccessibility in ERAs may provide a more realistic level of conservatism, thereby enhancing the accuracy of predicting risk to wildlife receptors. Furthermore, when numeric risk assessments are combined with site-specific biological data (i.e., biomarkers of exposure and effect), both lines of evidence can be used to make informed decisions about ecological risk and site management. PMID:22078367

  6. 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

  7. Hsp90 is important for fecundity, longevity, and buffering of cryptic deleterious variation in wild fly populations

    PubMed Central

    2012-01-01

    Background In the laboratory, the Drosophila melanogaster heat shock protein Hsp90 can buffer the phenotypic effects of genetic variation. Laboratory experiments either manipulate Hsp90 activity pharmacologically, or they induce mutations with strong effects in the gene Hsp83, the single-copy fly gene encoding Hsp90. It is unknown whether observations from such laboratory experiments are relevant in the wild. Results We here study naturally occurring mutations in Hsp83, and their effects on fitness and phenotypic buffering in flies derived from wild populations. We examined more than 4500 flies from 42 Drosophila populations distributed world-wide for insertions or deletions of mobile DNA in or near the Hsp83 gene. The insertions we observed occur at low population frequencies, and reduce Hsp83 gene expression. In competition experiments, mutant flies performed much more poorly than wild-type flies. Mutant flies were also significantly less fecund and shorter-lived than wild-type flies, as well as less well buffered against cryptic deleterious variation, as we show through inbreeding experiments. Specifically, in Hsp83 mutant flies female fecundity dropped to much lower levels after inbreeding than in wild-type flies. At even slightly elevated temperatures, inbred mutant Hsp83 populations went extinct, whereas inbred wild-type populations persisted. Conclusions Our work shows that Hsp90, a regulator of the stress response and of signaling, helps buffer deleterious variation in fruit flies derived from wild population, and that its buffering role becomes even more important under heat stress. PMID:22369091

  8. Systematic Study of the Genetic Response of a Variable Virus to the Introduction of Deleterious Mutations in a Functional Capsid Region?

    PubMed Central

    Luna, Eva; Rodríguez-Huete, Alicia; Rincón, Verónica; Mateo, Roberto; Mateu, Mauricio G.

    2009-01-01

    We have targeted the intersubunit interfaces in the capsid of foot-and-mouth disease virus to investigate the genetic response of a variable virus when individual deleterious mutations are systematically introduced along a functionally defined region of its genome. We had previously found that the individual truncation (by mutation to alanine) of 28 of the 42 amino acid side chains per protomer involved in interactions between capsid pentameric subunits severely impaired infectivity. We have now used viral RNAs individually containing each of those 28 deleterious mutations (or a few others) to carry out a total of 96 transfections of susceptible cells, generally followed by passage(s) of the viral progeny in cell culture. The results revealed a very high frequency of fixation in the capsid of second-site, stereochemically diverse substitutions that compensated for the detrimental effect of primary substitutions at many different positions. Most second-site substitutions occurred at or near the capsid interpentamer interfaces and involved residues that are spatially very close to the originally substituted residue. However, others occurred far from the primary substitution, and even from the interpentamer interfaces. Remarkably, most second-site substitutions involved only a few capsid residues, which acted as “second-site hot spots.” Substitutions at these hot spots compensated for the deleterious effects of many different replacements at diverse positions. The remarkable capacity of the virus to respond to the introduction of deleterious mutations in the capsid with the frequent fixation of diverse second-site mutations, and the existence of second-site hot spots, may have important implications for virus evolution. PMID:19625409

  9. 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.

  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. 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

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

    PubMed Central

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

    2007-01-01

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

  13. A novel deleterious PTEN mutation in a patient with early-onset bilateral breast cancer

    PubMed Central

    2014-01-01

    Background An early age at Breast Cancer (BC) onset may be a hallmark of inherited predisposition, but BRCA1/2 mutations are only found in a minority of younger BC patients. Among the others, a fraction may carry mutations in rarer BC genes, such as TP53, STK11, CDH1 and PTEN. As the identification of women harboring such mutations allows for targeted risk-management, the knowledge of associated manifestations and an accurate clinical and family history evaluation are warranted. Case presentation We describe the case of a woman who developed an infiltrating ductal carcinoma of the right breast at the age of 32, a contralateral BC at age 36 and another BC of the right breast at 40. When she was 39 years-old, during a dermatological examination, mucocutaneous features suggestive of Cowden Syndrome, a disorder associated to germ-line PTEN mutations, were noticed. PTEN genetic testing revealed the novel c.71A > T (p.Asp24Val) mutation, whose deleterious effect, suggested by conservation data and in silico tools, was definitely demonstrated by the incapacity of mutant PTEN to inhibit Akt phosphorylation when used to complement PTEN-null cells. In BC tissue, despite the absence of LOH or somatic mutations of PTEN, Akt phosphorylation was markedly increased in comparison to normal tissue, thus implying additional somatic events into the deregulation of the PI3K/Akt/mTOR pathway and, presumably, into carcinogenesis. Hence, known oncogenic mutations in PIK3CA (exons 10 and 21) and AKT1 (exon 2) were screened in tumor DNA with negative results, which suggests that the responsible somatic event(s) is a different, uncommon one. Conclusion This case stresses the importance of clinical/genetic assessment of early-onset BC patients in order to identify mutation carriers, who are at high risk of new events, so requiring tailored management. Moreover, it revealed a novel PTEN mutation with pathogenic effect, pointing out, however, the need for further efforts to elucidate the molecular steps of PTEN-associated carcinogenesis. PMID:24498881

  14. Is mitochondrial tRNA Cys G5821A a deleterious mutation?

    PubMed

    Wei, Lijuan; Gao, Wengen; Ma, Yafei; Cao, Quanxing; Zhang, Xianfen

    2015-04-01

    Although there are increasing reports showed a positive link between mitochondrial tRNACys G5821A mutation and mitochondrial diseases. However, its role remained controversial. In this paper, we took a comprehensive data analysis concerning this mutation and clinical diseases. Our data indicated that this mutation lacked an evolutionary conservation and did not get involved in the thermodynamic change of tRNACys gene. Therefore, based on these observations, we proposed that G5821A mutation is not deleterious mutation. PMID:24621223

  15. Prediction of deleterious non-synonymous SNPs based on protein interaction network and hybrid properties.

    PubMed

    Huang, Tao; Wang, Ping; Ye, Zhi-Qiang; Xu, Heng; He, Zhisong; Feng, Kai-Yan; Hu, Lele; Cui, Weiren; Wang, Kai; Dong, Xiao; Xie, Lu; Kong, Xiangyin; Cai, Yu-Dong; Li, Yixue

    2010-01-01

    Non-synonymous SNPs (nsSNPs), also known as Single Amino acid Polymorphisms (SAPs) account for the majority of human inherited diseases. It is important to distinguish the deleterious SAPs from neutral ones. Most traditional computational methods to classify SAPs are based on sequential or structural features. However, these features cannot fully explain the association between a SAP and the observed pathophysiological phenotype. We believe the better rationale for deleterious SAP prediction should be: If a SAP lies in the protein with important functions and it can change the protein sequence and structure severely, it is more likely related to disease. So we established a method to predict deleterious SAPs based on both protein interaction network and traditional hybrid properties. Each SAP is represented by 472 features that include sequential features, structural features and network features. Maximum Relevance Minimum Redundancy (mRMR) method and Incremental Feature Selection (IFS) were applied to obtain the optimal feature set and the prediction model was Nearest Neighbor Algorithm (NNA). In jackknife cross-validation, 83.27% of SAPs were correctly predicted when the optimized 263 features were used. The optimized predictor with 263 features was also tested in an independent dataset and the accuracy was still 80.00%. In contrast, SIFT, a widely used predictor of deleterious SAPs based on sequential features, has a prediction accuracy of 71.05% on the same dataset. In our study, network features were found to be most important for accurate prediction and can significantly improve the prediction performance. Our results suggest that the protein interaction context could provide important clues to help better illustrate SAP's functional association. This research will facilitate the post genome-wide association studies. PMID:20689580

  16. 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

  17. 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

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

    PubMed

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

    2010-01-01

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

  19. Ecological effects of overshooting stabilization targets for greenhouse gases for California plant species

    NASA Astrophysics Data System (ADS)

    Ries, L. P.; Hannah, L.; Thorne, J.; Seo, C.

    2008-12-01

    Stabilization of global greenhouse gas (GHG) concentrations at or below 350 ppm may be required to avoid catastrophic changes to the climate system. Although the level of stabilization is a primary concern, the pathway to reaching the target should also be considered as some pathways in reaching these goals could have more "dangerous impacts" than others. Since atmospheric GHG stands at 385pppm, achieving a 350ppm target will require overshoot - an exceedance of the target for several decades, followed by a gradual decline back to target levels. The UN Framework Convention on Climate Change aims to stabilize greenhouse gas concentrations to avoid dangerous interference with the climate. The EU has set a goal of 2 C warming. However the current trajectory of greenhouse gas emissions and associated temperature change suggest we are in danger of exceeding these goals and are committed to a certain degree of warming. Ecosystems are one benchmark of acceptable change in international policy, so are a relevant test of the value of low stabilization targets. The biological consequences of overshoot are unknown. Here we simulate the ecological effects of an overshoot strategy for the first time, for a series of California plants. We find that the portion of the species' range defined by the bioclimatic envelope is an important factor in determining the effects of an overshoot scenario and varies between species.

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

    NASA Astrophysics Data System (ADS)

    Xie, Jiancang; Zhu, Jiwei; Wang, Tao

    2010-05-01

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

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

    PubMed

    Camargo, Julio A; Alonso, Alvaro

    2006-08-01

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

  2. Sublethal effects and predator-prey interactions: implications for ecological risk assessment.

    PubMed

    Brooks, Amy C; Gaskell, Paul N; Maltby, Lorraine L

    2009-11-01

    Ecological risk assessments tend to focus on contaminant effects on single species in isolation. However, additional effects from interactions between species (e.g., predator-prey interactions) may also occur in natural systems. The present study investigated the consequences of sublethal contaminant effects in prey on predator-prey interactions, particularly the interaction between prey behavioral changes and predation by predators with different hunting strategies. Ambush (Ischnura elegans Vander Linden [Insecta, Odonata]) and active (Notonecta glauca Linnaeus [Insecta, Heteroptera]) predator species were used in conjunction with three prey species (Asellus aquaticus Linnaeus [Crustacea, Isopoda], Cloion dipterum Linnaeus [Insecta, Ephemeroptera], and Chironomus riparius Meigen [Insecta, Diptera]). Immobilized prey demonstrated the importance of prey behavior for determining predation rates for both single- and multiple-prey species. Chironomus riparius was less responsive following exposure to cadmium, becoming more vulnerableto attack by the active but not the ambush predator. Some evidence was also observed for reduced general activity in C. dipterum following cadmium exposure. Sublethal exposure of prey did not affect the prey choice of active predators, possibly because of prey behavioral changes being insufficient to influence their relative availabilities. However, cadmium exposure of prey did alter their susceptibility to ambush predators. There was a reduced proportion of C. dipterum and an increased proportion of A. aquaticus in the diet of ambush predators, possibly because of reduced activity in C. dipterum affecting their relative encounter rates with predators. Sublethal exposures can therefore result in reduced prey survival that would not be predicted by single-species toxicity tests. PMID:19572771

  3. Effects of the antibiotic enrofloxacin on the ecology of tropical eutrophic freshwater microcosms.

    PubMed

    Rico, Andreu; Dimitrov, Mauricio R; Van Wijngaarden, René P A; Satapornvanit, Kriengkrai; Smidt, Hauke; Van den Brink, Paul J

    2014-02-01

    The main objective of the present study was to assess the ecological impacts of the fluoroquinolone antibiotic enrofloxacin on the structure and functioning of tropical freshwater ecosystems. Enrofloxacin was applied at a concentration of 1, 10, 100 and 1,000 ?g/L for 7 consecutive days in 600-L outdoor microcosms in Thailand. The ecosystem-level effects of enrofloxacin were monitored on five structural (macroinvertebrates, zooplankton, phytoplankton, periphyton and bacteria) and two functional (organic matter decomposition and nitrogen cycling) endpoint groups for 4 weeks after the last antibiotic application. Enrofloxacin was found to dissipate relatively fast from the water column (half-dissipation time: 11.7h), and about 11% of the applied dose was transformed into its main by-product ciprofloxacin after 24h. Consistent treatment-related effects on the invertebrate and primary producer communities and on organic matter decomposition could not be demonstrated. Enrofloxacin significantly affected the structure of leaf-associated bacterial communities at the highest treatment level, and reduced the abundance of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in the sediments, with calculated NOECs of 10 and <1 ?g/L, respectively. The ammonia concentration in the microcosm water significantly increased in the highest treatment level, and nitrate production was decreased, indicating a potential impairment of the nitrification function at concentrations above 100 ?g/L. The results of this study suggest that environmentally relevant concentrations of enrofloxacin are not likely to result in direct or indirect toxic effects on the invertebrate and primary producer communities, nor on important microbially mediated functions such as nitrification. PMID:24380725

  4. 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.

  5. 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

  6. Significance and Effect of Ecological Rehabilitation Project in Inland River Basins in Northwest China

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Pérez, Francisco L.

    1989-06-01

    The effect of giant Andean stem-rosettes ( Coespeletia lutescens) on air and soil temperatures was studied in the Páramo 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 7.0°C higher than in the open. This substantially reduced the intensity of nightly freezing. Soil temperature minima at 20 cm depth were 2.4° to 4.2°C 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.

  8. 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...

  9. Exploring the effects of local development regulations on ecological landscape structure 

    E-print Network

    Kim, Jin Ki

    2005-08-29

    An ecological approach to land-use planning is essential to maintain the long-term sustainability of ecosystem benefits, services, and resources. Concern about environmental quality and the long-term livability of urban ...

  10. 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.

  11. Effects of pyrite sludge pollution on soil enzyme activities: ecological dose-response model.

    PubMed

    Hinojosa, M Belén; Carreira, José A; Rodríguez-Maroto, José M; García-Ruíz, Roberto

    2008-06-25

    A laboratory study was conducted to evaluate the response of soil enzyme activities (acid and alkaline phosphatase, beta-glucosidase, arylsulfatase, urease and dehydrogenase) to different levels of trace elements pollution in soils representative of the area affected by the pyrite sludge mining spill of Aznalcóllar (Guadiamar basin, SW Spain). Three uncontaminated soils from the study area were mixed with different loads of pyrite sludge to resemble field conditions and criteria applied for reclamation practices following the pollution incident: 0% ("reference" or background level), 1.3% ("attention level", further monitoring required), 4% ("intervention level", further cleaning and liming required) and 13% (ten times the "attention level"). Enzyme activities were analysed 4, 7, 14, 21, 34 and 92 days after pollutant addition and those measured after 92 days were used to calculate the ecological dose value (ED50). Soil enzyme activities and pH decreased after the pyrite sludge addition with respect to the "reference level" (0% pyrite sludge), whereas soil bioavailable (DTPA-extractable) trace elements concentration increased. Arylsulfatase, beta-glucosidase and phosphatase activities were reduced by more than 50% at 1.3% pyrite sludge dose. Arylsulfasate was the most sensitive soil enzyme (in average, ED50=0.99), whereas urease activity showed the lowest inhibition (in average, ED50=7.87) after pyrite sludge addition. Our results showed that the ecological dose concept, applied to enzyme activities, was satisfactory to quantify the effect of a multi-metalic pollutant (pyrite sludge) on soil functionality, and would provide manageable data to establish permissible limits of trace elements in polluted soils. Additionally, we evaluate the recovery of enzyme activities after addition of sugar-beet lime (calcium carbonate) to each experimentally polluted soil. The amount of lime added to each soil was enough to raise the pH to the original value (equal to control soil), resembling field remediation practices. After lime amendment, soil recovery was still incomplete in terms of bioavailable trace elements. However, the recovery of soil enzyme activities varied widely, ranging from 0 to 100% depending on soil type and the specific enzyme. PMID:18395245

  12. Fermented and nonfermented liquid feed to growing pigs: Effect on aspects of gastrointestinal ecology and growth performance

    Microsoft Academic Search

    N. Canibe; B. B. Jensen

    2010-01-01

    The effect of feeding dry feed (DF), non- fermented liquid feed (NFLF), and fermented liquid feed(FLF)togrowingpigsonaspectsofgastrointestinal ecology and on performance was investigated. Nonfer- mented liquid feed was prepared by mixing feed and water at a ratio of 1:2.5 immediately before feeding. Fermented liquid feed was prepared by mixing feed and water in the same ratio as NFLF, and stored in

  13. 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...

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

    USGS Publications Warehouse

    McKnight, D.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.

  15. 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,…

  16. Perspectives in Plant Ecology,

    E-print Network

    Traveset, Anna

    been many studies of ecological and evolutionary as- pects of frugivory and seed dispersal by ani- malsPerspectives in Plant Ecology, Evolution and Systematics Vol. 1/2, pp. 151­190 © Gustav Fischer Verlag, 1998 Effect of seed passage through vertebrate frugivores' guts on germination: a review Anna

  17. Effects of ecological flooding on the temporal and spatial dynamics of carabid beetles (Coleoptera, Carabidae) and springtails (Collembola) in a polder habitat

    PubMed Central

    Lessel, Tanja; Marx, Michael Thomas; Eisenbeis, Gerhard

    2011-01-01

    Abstract Within the scope of the Integrated Rhine Program an ecological flood gate and channel was inserted into the polder “Ingelheim” to enhance animal and plant diversity. In 2008, carabid beetles and springtails were collected, using pitfall traps, to measure the effects of ecological flooding and a strong precipitation event at a flood-disturbed and a dry location in this area. At both localities, xerophilic and mesophilic carabid beetle species were dominant throughout the study period. The total number of individuals of hygrophilic species was comparatively constant, while species number increased, partly due to the changed moisture conditions caused by ecological flooding and strong precipitation. Carabid beetle diversity and evenness decreased marginally when ecological flooding was absent. Springtails represent a less mobile arthropod order, and as such the impact of ecological flooding was stronger. An increase in both numbers of species and individuals of hygrophilic and hygrotolerant species occurred in the flood-disturbed location after ecological flooding. After the sites at both locations had dried, the number of individuals belonging to these species declined rapidly. In contrast to carabid species, the strong precipitation event showed no influence on hygrophilic springtail species. Thus, collembolan diversity and evenness decreased markedly in the absence of flooding. We showed that ecological flooding has an influence on the spatial and temporal dynamics of different arthropod groups that inhabit the polder “Ingelheim”. These findings demonstrate the importance of using different arthropod groups as bioindicators in determining the ecological value of a particular polder design. PMID:21738425

  18. Ecological effect of ceftazidime/avibactam on the normal human intestinal microbiota.

    PubMed

    Rashid, Mamun-Ur; Rosenborg, Staffan; Panagiotidis, Georgios; Löfdal, Karin Söderberg; Weintraub, Andrej; Nord, Carl Erik

    2015-07-01

    Ceftazidime/avibactam is a new combination of the antibiotic ceftazidime with the novel, non-?-lactam ?-lactamase inhibitor avibactam. The purpose of the present study was to investigate the effect of ceftazidime/avibactam on the human intestinal microbiota following intravenous (i.v.) administration. Twelve healthy volunteers received ceftazidime/avibactam by i.v. infusion (2000mg ceftazidime and 500mg avibactam) given over 2h every 8h on Days 1-6 (inclusive) and a single dose on Day 7. Faecal samples were collected on Day-1 (pre-dose), during administration on Days 2, 5 and 7 and post-dose on Days 9, 14 and 21. Samples were cultured on non-selective and selective media. The number of Escherichia coli and other enterobacteria decreased significantly during administration of ceftazidime/avibactam, whereas the number of enterococci increased. Lactobacilli, bifidobacteria, clostridia and Bacteroides decreased significantly during ceftazidime/avibactam administration. The effects on lactobacilli, bifidobacteria and Bacteroides were similar in the 12 volunteers, whilst clostridia showed different ecological patterns among the volunteers. Toxigenic Clostridium difficile strains were detected in five volunteers during the study. In four of the volunteers, loose stools were reported as adverse events. Plasma samples were collected on Days -1, 2, 5 and 7. Ceftazidime and avibactam concentrations in plasma (ceftazidime 0-224.2mg/L of plasma and avibactam 0-70.5mg/L of plasma) and faeces (ceftazidime 0-468.2mg/kg of faeces and avibactam 0-146.0mg/kg of faeces) were found by bioassay. New colonising resistant clostridia were found in five volunteers and lactobacilli were found in three volunteers. PMID:25979639

  19. Increased burden of de novo predicted deleterious variants in complex congenital diaphragmatic hernia.

    PubMed

    Yu, Lan; Sawle, Ashley D; Wynn, Julia; Aspelund, Gudrun; Stolar, Charles J; Arkovitz, Marc S; Potoka, Douglas; Azarow, Kenneth S; Mychaliska, George B; Shen, Yufeng; Chung, Wendy K

    2015-08-15

    Congenital diaphragmatic hernia (CDH) is a serious birth defect that accounts for 8% of all major birth anomalies. Approximately 40% of cases occur in association with other anomalies. As sporadic complex CDH likely has a significant impact on reproductive fitness, we hypothesized that de novo variants would account for the etiology in a significant fraction of cases. We performed exome sequencing in 39 CDH trios and compared the frequency of de novo variants with 787 unaffected controls from the Simons Simplex Collection. We found no significant difference in overall frequency of de novo variants between cases and controls. However, among genes that are highly expressed during diaphragm development, there was a significant burden of likely gene disrupting (LGD) and predicted deleterious missense variants in cases (fold enrichment = 3.2, P-value = 0.003), and these genes are more likely to be haploinsufficient (P-value = 0.01) than the ones with benign missense or synonymous de novo variants in cases. After accounting for the frequency of de novo variants in the control population, we estimate that 15% of sporadic complex CDH patients are attributable to de novo LGD or deleterious missense variants. We identified several genes with predicted deleterious de novo variants that fall into common categories of genes related to transcription factors and cell migration that we believe are related to the pathogenesis of CDH. These data provide supportive evidence for novel genes in the pathogenesis of CDH associated with other anomalies and suggest that de novo variants play a significant role in complex CDH cases. PMID:26034137

  20. SDS, a structural disruption score for assessment of missense variant deleteriousness.

    PubMed

    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

  1. Journal of Animal Ecology 2005

    E-print Network

    Elkinton, Joseph

    Journal of Animal Ecology 2005 74, 1005­1019 © 2005 British Ecological Society Blackwell Publishing, Ltd. Predation of beech seed by mice: effects of numerical and functional responses WENDY A. RUSCOE Zealand; Department of Entomology, and Graduate Program in Ecology and Evolutionary Biology, University

  2. Eco-genetic model to explore fishing-induced ecological and evolutionary effects on growth and maturation schedules

    PubMed Central

    Wang, Hui-Yu; Höök, Tomas O

    2009-01-01

    Eco-genetic individual-based models involve tracking the ecological dynamics of simulated individual organisms that are in part characterized by heritable parameters. We developed an eco-genetic individual-based model to explore ecological and evolutionary interactions of fish growth and maturation schedules. Our model is flexible and allows for exploration of the effects of heritable growth rates (based on von Bertalanffy and biphasic growth patterns), heritable maturation schedules (based on maturation reaction norm concepts), or both on individual- and population-level traits. In baseline simulations with rather simple ecological trade-offs and over a relatively short time period (<200 simulation years), simulated male and female fish evolve differential genetic growth and maturation. Further, resulting patterns of genetically determined growth and maturation are influenced by mortality rate and density-dependent processes, and maturation and growth parameters interact to mediate the evolution of one another. Subsequent to baseline simulations, we conducted experimental simulations to mimic fisheries harvest with two size-limits (targeting large or small fish), an array of fishing mortality rates, and assuming a deterministic or stochastic environment. Our results suggest that fishing with either size-limit may induce considerable changes in life-history trait expression (maturation schedules and growth rates), recruitment, and population abundance and structure. However, targeting large fish would cause more adverse genetic effects and may lead to a population less resilient to environmental stochasticity. PMID:25567890

  3. 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...

  4. Evolution- and structure-based computational strategy reveals the impact of deleterious missense mutations on MODY 2 (maturity-onset diabetes of the young, type 2).

    PubMed

    George, Doss C Priya; Chakraborty, Chiranjib; Haneef, S A Syed; Nagasundaram, Nagarajan; Chen, Luonan; Zhu, Hailong

    2014-01-01

    Heterozygous mutations in the central glycolytic enzyme glucokinase (GCK) can result in an autosomal dominant inherited disease, namely maturity-onset diabetes of the young, type 2 (MODY 2). MODY 2 is characterised by early onset: it usually appears before 25 years of age and presents as a mild form of hyperglycaemia. In recent years, the number of known GCK mutations has markedly increased. As a result, interpreting which mutations cause a disease or confer susceptibility to a disease and characterising these deleterious mutations can be a difficult task in large-scale analyses and may be impossible when using a structural perspective. The laborious and time-consuming nature of the experimental analysis led us to attempt to develop a cost-effective computational pipeline for diabetic research that is based on the fundamentals of protein biophysics and that facilitates our understanding of the relationship between phenotypic effects and evolutionary processes. In this study, we investigate missense mutations in the GCK gene by using a wide array of evolution- and structure-based computational methods, such as SIFT, PolyPhen2, PhD-SNP, SNAP, SNPs&GO, fathmm, and Align GVGD. Based on the computational prediction scores obtained using these methods, three mutations, namely E70K, A188T, and W257R, were identified as highly deleterious on the basis of their effects on protein structure and function. Using the evolutionary conservation predictors Consurf and Scorecons, we further demonstrated that most of the predicted deleterious mutations, including E70K, A188T, and W257R, occur in highly conserved regions of GCK. The effects of the mutations on protein stability were computed using PoPMusic 2.1, I-mutant 3.0, and Dmutant. We also conducted molecular dynamics (MD) simulation analysis through in silico modelling to investigate the conformational differences between the native and the mutant proteins and found that the identified deleterious mutations alter the stability, flexibility, and solvent-accessible surface area of the protein. Furthermore, the functional role of each SNP in GCK was identified and characterised using SNPeffect 4.0, F-SNP, and FASTSNP. We hope that the observed results aid in the identification of disease-associated mutations that affect protein structure and function. Our in silico findings provide a new perspective on the role of GCK mutations in MODY2 from an evolution-based structure-centric point of view. The computational architecture described in this paper can be used to predict the most appropriate disease phenotypes for large-genome sequencing projects and to provide individualised drug therapy for complex diseases such as diabetes. PMID:24578721

  5. Toxic effects of Cadmium on the garden snail (Helix aspersa)

    SciTech Connect

    Russell, L.K. (Northrop Services Inc., Corvallis, OR); DeHaven, J.I.; Botts, R.P.

    1981-05-01

    Spreading treated municipal wastes on agricultural and forest lands is becoming an established method of disposal. However, there is concern about the deleterious effects of toxicants, particularly cadmium, in the sludges. Cadmium concentrations in sewage sludge have been reported as high as 1500 ppM. The work reported here is a part of a larger project to investigate the ecological effects of municipal wastes on forest lands. Snails, Helix aspersa, were chosen to examine the entrance of cadmium into terrestrial food chains. This experiment was designed to determine cadmium accumulation, acute toxicity, and behavioral, reproductive and growth responses with increasing levels of cadmium.

  6. 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.

  7. Mekong River fish conservation zones in southern Laos: assessing effectiveness using local ecological knowledge.

    PubMed

    Baird, Ian G; Flaherty, Mark S; Baird, Ian G

    2005-09-01

    Small-scale fisheries are important in Laos, where rural people heavily depend upon Mekong River and tributary fish stocks for their livelihoods. Increasing pressures from human exploitation and habitat disturbance, however, have raised serious concerns about the potential depletion of various species. This has led to the establishment of large numbers of Fish Conservation Zones (FCZs) or "no-take" fish sanctuaries in southern Laos based on a "community-based fisheries co-management" framework. This study uses the local ecological knowledge (LEK) of fishers to assess the effectiveness of village-managed FCZs in enhancing fish stocks in the mainstream Mekong River in Khong District, Champasak Province. Focus group interviews about species that are believed to have benefited from different FCZs are compared with parameters such as FCZ area, age, depth, localized gradient, water velocity, and the presence of wetland forests nearby. The results suggest that no one aspect is likely to account for variations in fish stocks; rather, it is the interaction between numerous factors that has the largest impact. Secondly, the results indicate that microhabitat diversity and protection are critical for maintaining and enhancing Mekong fisheries. Deep-water pools are particularly important as dry season refuges for many fish species, and FCZ depth may be the single most important environmental factor affecting the success of FCZs in the Mekong River. FCZs have the most potential to benefit relatively sedentary species, but may also benefit highly migratory species, given the right conditions. This study shows that integrated approaches to stock assessment that employ LEK and scientific fisheries management have considerable potential for improving Mekong capture-fisheries management. PMID:16132441

  8. Computational and structural investigation of deleterious functional SNPs in breast cancer BRCA2 gene.

    PubMed

    Rajasekaran, R; Doss, George Priya; Sudandiradoss, C; Ramanathan, K; Rituraj, Purohit; Sethumadhavan, Rao

    2008-05-01

    In this work, we have analyzed the genetic variation that can alter the expression and the function in BRCA2 gene using computational methods. Out of the total 534 SNPs, 101 were found to be non synonymous (nsSNPs). Among the 7 SNPs in the untranslated region, 3 SNPs were found in 5' and 4 SNPs were found in 3' un-translated regions (UTR). Of the nsSNPs 20.7% were found to be damaging by both SIFT and PolyPhen server among the 101 nsSNPs investigated. UTR resource tool suggested that 2 SNPs in the 5' UTR region and 4 SNPs in the 3' UTR regions might change the protein expression levels. The mutation from asparagine to isoleucine at the position 3124 of the native protein of BRCA2 gene was most deleterious by both SIFT and PolyPhen servers. A structural analysis of this mutated protein and the native protein was made which had an RMSD value of 0.301 nm. Based on this work, we proposed that this most deleterious nsSNP with an SNPid rs28897759 is an important candidate for the cause of breast cancer by BRCA2 gene. PMID:18724707

  9. Adapting to Climate Change on Western Public Lands: Addressing the Ecological Effects of Domestic, Wild, and Feral Ungulates

    NASA Astrophysics Data System (ADS)

    Beschta, Robert L.; Donahue, Debra L.; DellaSala, Dominick A.; Rhodes, Jonathan J.; Karr, James R.; O'Brien, Mary H.; Fleischner, Thomas L.; Deacon Williams, Cindy

    2013-02-01

    Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an altered environment. Historical and contemporary livestock production—the most widespread and long-running commercial use of public lands—can alter vegetation, soils, hydrology, and wildlife species composition and abundances in ways that exacerbate the effects of climate change on these resources. Excess abundance of native ungulates (e.g., deer or elk) and feral horses and burros add to these impacts. Although many of these consequences have been studied for decades, the ongoing and impending effects of ungulates in a changing climate require new management strategies for limiting their threats to the long-term supply of ecosystem services on public lands. Removing or reducing livestock across large areas of public land would alleviate a widely recognized and long-term stressor and make these lands less susceptible to the effects of climate change. Where livestock use continues, or where significant densities of wild or feral ungulates occur, management should carefully document the ecological, social, and economic consequences (both costs and benefits) to better ensure management that minimizes ungulate impacts to plant and animal communities, soils, and water resources. Reestablishing apex predators in large, contiguous areas of public land may help mitigate any adverse ecological effects of wild ungulates.

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

    Microsoft Academic Search

    S. C. Schroeter; J. D. Dixon; J. Kastendiek; R. O. Smith; J. R. Bence

    1993-01-01

    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

  11. A review of the ecological effects of river regulation in Australia

    Microsoft Academic Search

    K. F. Walker

    1985-01-01

    Responses to hydrologic change are an important theme in lotic ecology, and data for Australian rivers are accumulating in a rapid, butad hoc manner. Thia paper arranges recent contributions according to the major drainage divisions, which provide reasonably coherent environmental units. The east coastal rivers are exploited for storage, power generation and waste disposal, and Tasmanian rivers are regulated to

  12. Cascading effects of introduced Nile perch (Lates niloticus) on the foraging ecology of Nile tilapia

    E-print Network

    Chapman, Lauren J.

    - indigenous fish species in the Lake Victoria Basin of East Africa has been followed by dramatic ecological 2000; Pringle 2005). Although many fish stocks in Lake Victoria had declined prior to expansion followed that observed in Lake Victoria (Ogutu- Ohwayo 1993; Chapman et al. 1996a,b). Four non- indigenous

  13. ECOLOGICAL ENDPOINT MODELING FOR TMDLS: EFFECTS OF SEDIMENT ON FISH POPULATIONS

    EPA Science Inventory

    Sediment is one of the primary stressors of concern for Total Maximum Daily Loads (TMDLs) for streams, and often it is a concern because of its impact on ecological endpoints. A modeling approach relating sediment to stream fish population dynamics is presented. Equations are d...

  14. The Ecological and Population Validity of Reading Interventions for Adolescents: Can Effectiveness Be Generalized?

    ERIC Educational Resources Information Center

    Reed, Deborah K.; McCray Sorrells, Audrey; Cole, Heather A.; Takakawa, Nara N.

    2013-01-01

    This article examined the ecological and population validity of research on reading interventions for adolescents in Grades 6 through 12. The 26 studies meeting selection criteria were analyzed to determine the characteristics of the students, interventionists, classroom structures, and school environments used, as well as whether there were…

  15. 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 ...

  16. 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...

  17. ECOLOGICAL INDICATORS

    EPA Science Inventory

    An international symposium on ecological indicators was developed to explore both the potential of ecological indicators and the issues surrounding their development and implementation. his symposium presented state-of-the-science information on the identification, application re...

  18. 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)

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

    PubMed

    Velki, Mirna; Hackenberger, Branimir K; Lon?ari?, Zeljka; Hackenberger, Davorka K

    2014-06-01

    Earthworms from different ecological categories--epigeic Eisenia andrei and Lumbricus rubellus, endogeic Octolasion lacteum and anecic Lumbricus terrestris--were exposed in a microcosmic system to three commonly used insecticides. The effects of the insecticides were evaluated by measuring the following molecular biomarkers-the activities of AChE, CES, CAT, GST and the concentration of GSH. The results showed that environmentally relevant doses of organophosphates dimethoate and pirimiphos-methyl significantly affected the measured biomarkers, whereas pyrethroid deltamethrin did not affect the earthworms at the recommended agricultural dose. Considering the ecological category of earthworms, the results were inhomogeneous and species-specific differences in the biomarker responses were recorded. Since the biomarker responses of the investigated earthworm species were different after exposure to organophosphates in a microcosm compared to the exposure via standardized toxicity tests, two types of species sensitivity should be distinguished-physiological and environmental sensitivity. In addition, the hormetic effect of organophosphates on AChE and CES activities was recorded. The detection of hormesis in a microcosm is of great importance for future environmental research and soil biomonitoring, since in a realistic environment pollutants usually occur at low concentrations that could cause a hormetic effect. The results demonstrate the importance of the application of microcosmic systems in the assessment of the effects of environmental pollutants and the necessity of taking into account the possible differences between physiological and environmental species sensitivity. PMID:24650551

  20. Deleterious impact of Pseudomonas aeruginosa on cystic fibrosis transmembrane conductance regulator function and rescue in airway epithelial cells.

    PubMed

    Trinh, Nguyen Thu Ngan; Bilodeau, Claudia; Maillé, Émilie; Ruffin, Manon; Quintal, Marie-Claude; Desrosiers, Martin-Yvon; Rousseau, Simon; Brochiero, Emmanuelle

    2015-06-01

    The epithelial response to bacterial airway infection, a common feature of lung diseases such as chronic obstructive pulmonary disease and cystic fibrosis, has been extensively studied. However, its impact on cystic fibrosis transmembrane conductance regulator (CFTR) channel function is not clearly defined. Our aims were, therefore, to evaluate the effect of Pseudomonas aeruginosa on CFTR function and expression in non-cystic fibrosis airway epithelial cells, and to investigate its impact on ?F508-CFTR rescue by the VRT-325 corrector in cystic fibrosis cells. CFTR expression/maturation was evaluated by immunoblotting and its function by short-circuit current measurements. A 24-h exposure to P. aeruginosa diffusible material (PsaDM) reduced CFTR currents as well as total and membrane protein expression of the wildtype (wt) CFTR protein in CFBE-wt cells. In CFBE-?F508 cells, PsaDM severely reduced CFTR maturation and current rescue induced by VRT-325. We also confirmed a deleterious impact of PsaDM on wt-CFTR currents in non-cystic fibrosis primary airway cells as well as on the rescue of ?F508-CFTR function induced by VRT-325 in primary cystic fibrosis cells. These findings show that CFTR function could be impaired in non-cystic fibrosis patients infected by P. aeruginosa. Our data also suggest that CFTR corrector efficiency may be affected by infectious components, which should be taken into account in screening assays of correctors. PMID:25792634

  1. Ecological Footprint

    NSDL National Science Digital Library

    2007-01-01

    Students explore their own Ecological Footprint in the context of how many Earths it would take if everyone used the same amount of resources they did. They compare this to the Ecological Footprint of individuals in other parts of the world and to the Ecological footprint of a family member when they were the student's age.

  2. Quantifying rare, deleterious variation in 12 human cytochrome P450 drug-metabolism genes in a large-scale exome dataset

    PubMed Central

    Gordon, Adam S.; Tabor, Holly K.; Johnson, Andrew D.; Snively, Beverly M.; Assimes, Themistocles L.; Auer, Paul L.; Ioannidis, John P.A.; Peters, Ulrike; Robinson, Jennifer G.; Sucheston, Lara E.; Wang, Danxin; Sotoodehnia, Nona; Rotter, Jerome I.; Psaty, Bruce M.; Jackson, Rebecca D.; Herrington, David M.; O'Donnell, Christopher J.; Reiner, Alexander P.; Rich, Stephen S.; Rieder, Mark J.; Bamshad, Michael J.; Nickerson, Deborah A.

    2014-01-01

    The study of genetic influences on drug response and efficacy (‘pharmacogenetics’) has existed for over 50 years. Yet, we still lack a complete picture of how genetic variation, both common and rare, affects each individual's responses to medications. Exome sequencing is a promising alternative method for pharmacogenetic discovery as it provides information on both common and rare variation in large numbers of individuals. Using exome data from 2203 AA and 4300 Caucasian individuals through the NHLBI Exome Sequencing Project, we conducted a survey of coding variation within 12 Cytochrome P450 (CYP) genes that are collectively responsible for catalyzing nearly 75% of all known Phase I drug oxidation reactions. In addition to identifying many polymorphisms with known pharmacogenetic effects, we discovered over 730 novel nonsynonymous alleles across the 12 CYP genes of interest. These alleles include many with diverse functional effects such as premature stop codons, aberrant splicesites and mutations at conserved active site residues. Our analysis considering both novel, predicted functional alleles as well as known, actionable CYP alleles reveals that rare, deleterious variation contributes markedly to the overall burden of pharmacogenetic alleles within the populations considered, and that the contribution of rare variation to this burden is over three times greater in AA individuals as compared with Caucasians. While most of these impactful alleles are individually rare, 7.6–11.7% of individuals interrogated in the study carry at least one newly described potentially deleterious alleles in a major drug-metabolizing CYP. PMID:24282029

  3. 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.

  4. 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.

  5. Effects of carcinogenic versus non-carcinogenic AHR-active PAHs and their mixtures: lessons from ecological relevance.

    PubMed

    Martins, Marta; Santos, José M; Diniz, Mário S; Ferreira, Ana M; Costa, Maria H; Costa, Pedro M

    2015-04-01

    Polycyclic aromatic hydrocarbons (PAHs) are priority environmental mutagens and carcinogens that occur in the aquatic environment as mixtures rather than the individual compounds for which guidelines are issued. The present work aimed at understanding the interaction effects between carcinogenic and non-carcinogenic PAHs in a model marine fish (Dicentrarchus labrax) in realistic scenarios. Laboratory assays under ecologically-relevant parameters were conducted for 28 days with sediments spiked with low-moderate concentrations (250-800ngg(-1)) of two model PAHs, phenanthrene (non-carcinogenic) and benzo[b]fluoranthene (carcinogenic to experimental animals). Both PAHs induced hepatic histopathological changes that indicate metabolic failure and inflammation, especially in animals exposed to mixtures. Phenanthrene elicited biochemical changes better related to oxidative stress (lipid peroxidation, glutathione and glutathione S-transferase activity) and CYP function, whereas B[b]F disrupted metabolic responses and defences to toxicological challenge. Conversely, mixed PAHs yielded lesions and responses that, altogether, are compatible with the AHR dependent pathway (the basis of PAH mutagenicity), potentially generating supra-additive effects. Nonetheless, the low, ecologically-relevant, concentrations of PAHs diluted dose and time-response relations. Overall, although seemingly predicting the risk of individual PAHs, environmental guidelines may not apply to mixtures by underestimating adverse effects, which calls for a redefinition of standards when determining the true risk of toxicants under realistic circumstances. PMID:25704830

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

    PubMed

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

    2011-11-01

    Tests of rodent visual capacities are typically performed under standard laboratory illumination. However, light level can have subtle and complex effects on behavior in rodents. We tested Mongolian gerbils (Meriones unguiculatus) - a species that shows individual differences in activity pattern - on visual tasks at three ecologically relevant levels of ambient illuminance: approximating moonlight (1 lx), dawn or dusk (10 lx), and low daylight (100 lx). A jumping task and a grating discrimination quantified depth perception and grating acuity, respectively. Illuminance variations had important effects on behavior. Gerbils jumped faster in lower light on the depth discrimination task, but were also less accurate than in bright light. Daytime activity levels (possibly reflecting variations in activity pattern) mediated these effects, with animals that were awake during a lower proportion of daytime hours exhibiting a trend toward jumping faster with lower light level as compared to more day-active gerbils. Moreover, while illuminance did not affect acuity overall, it interacted with activity levels in a complex way: in both the darkest and lowest light levels, animals that were awake during a greater proportion of daytime hours showed higher acuity levels than animals that were less active during the day. These results indicate that gerbils show behavioral profiles in vision tasks that represent an interaction between visual ability and illuminance-sensitive motivational or emotional actors, perhaps including chronotype. Thus, the most ecologically relevant assessments of the visual performance of rodents will likely be achieved by testing at species-specific preferred light levels. PMID:21906663

  7. 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

  8. Relative Effectiveness of Expository and Field Trip Methods of Teaching on Students' Achievement in Ecology

    ERIC Educational Resources Information Center

    Hamilton-Ekeke, Joy-Telu

    2007-01-01

    The study was a pre-test treatment post-test control design. Three educational districts from the Niger Delta region of Nigeria were treated as clusters. Twenty boys and 20 girls were randomly selected, making up a total of 40 students, in each of Group A, Group B, and Group C. Students in Group A were taught ecology by taking them to the school…

  9. 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

  10. Computational screening and molecular dynamic simulation of breast cancer associated deleterious non-synonymous single nucleotide polymorphisms in TP53 gene.

    PubMed

    Chitrala, Kumaraswamy Naidu; Yeguvapalli, Suneetha

    2014-01-01

    Breast cancer is one of the most common cancers among the women around the world. Several genes are known to be responsible for conferring the susceptibility to breast cancer. Among them, TP53 is one of the major genetic risk factor which is known to be mutated in many of the breast tumor types. TP53 mutations in breast cancer are known to be related to a poor prognosis and chemo resistance. This renders them as a promising molecular target for the treatment of breast cancer. In this study, we present a computational based screening and molecular dynamic simulation of breast cancer associated deleterious non-synonymous single nucleotide polymorphisms in TP53. We have predicted three deleterious coding non-synonymous single nucleotide polymorphisms rs11540654 (R110P), rs17849781 (P278A) and rs28934874 (P151T) in TP53 with a phenotype in breast tumors using computational tools SIFT, Polyphen-2 and MutDB. We have performed molecular dynamics simulations to study the structural and dynamic effects of these TP53 mutations in comparison to the wild-type protein. Results from our simulations revealed a detailed consequence of the mutations on the p53 DNA-binding core domain that may provide insight for therapeutic approaches in breast cancer. PMID:25105660

  11. The virus of my virus is my friend: ecological effects of virophage with alternative modes of coinfection.

    PubMed

    Taylor, Bradford P; Cortez, Michael H; Weitz, Joshua S

    2014-08-01

    Virophages are viruses that rely on the replication machinery of other viruses to reproduce within eukaryotic hosts. Two different modes of coinfection have been posited based on experimental observation. In one mode, the virophage and the virus enter the host independently. In the other mode, the virophage adheres to the virus so both virophage and virus enter the host together. Here we ask: what are the ecological effects of these different modes of coinfection? In particular, what ecological effects are common to both infection modes, and what are the differences particular to each mode? We develop a pair of biophysically motivated ODE models of viral-host population dynamics, corresponding to dynamics arising from each mode of infection. We find that both modes of coinfection allow for the coexistence of the virophage, virus, and host either at a stable fixed point or through cyclical dynamics. In both models, virophage tends to be the most abundant population and their presence always reduces the viral abundance and increases the host abundance. However, we do find qualitative differences between models. For example, via extensive sampling of biologically relevant parameter space, we only observe bistability when the virophage and the virus enter the host together. We discuss how such differences may be leveraged to help identify modes of infection in natural environments from population level data. PMID:24662503

  12. 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

  13. RAGE: The beneficial and deleterious effects by diverse mechanisms of actions

    Microsoft Academic Search

    Sun-Ho Han; Yoon Hee Kim; Inhee Mook-Jung

    2011-01-01

    Receptor for advanced glycation endproducts (RAGE) is a transmembrane protein that belongs to the immunoglobulin superfamily.\\u000a RAGE is expressed ubiquitously-high in lung and moderate to low in a wide range of cells-in a tightly regulated manner at\\u000a various stages of development. RAGE is a pattern recognition receptor that binds to multiple ligands, including amphoterin,\\u000a members of the S100\\/calgranulin family, the

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

    E-print Network

    Blaustein, Leon

    of amphibians and other aquatic fauna. The mosquito- fish, Gambusia affinis, commonly stocked into amphibian breeding sites for mosquito control worldwide, has recently been found in some breeding sites of the endangered fire salamander Salamandra infraimmaculata in northern Israel. A comparison of Salamandra larvae

  15. NSAID-induced deleterious effects on the proximal and mid small bowel in seronegative spondyloarthropathy patients

    PubMed Central

    Rimba?, Mihai; Marinescu, M?d?lina; Voiosu, Mihail Radu; B?icu?, Cristian R?svan; Caraiola, Simona; Nicolau, Adriana; Ni?escu, Doina; Badea, Georgeta Camelia; Pârvu, Magda Ileana

    2011-01-01

    AIM: To investigate the small bowel of seronegative spondyloarthropathy (SpA) patients in order to ascertain the presence of mucosal lesions. METHODS: Between January 2008 and June 2010, 54 consecutive patients were enrolled and submitted to avideo capsule endoscopy (VCE) examination. History and demographic data were taken, as well as the history of non-steroidal anti-inflammatory drug (NSAID) consumption. After reading each VCE recording, a capsule endoscopy scoring index for small bowel mucosal inflammatory change (Lewis score) was calculated. Statistical analysis of the data was performed. RESULTS: The Lewis score for the whole cohort was 397.73. It was higher in the NSAID consumption subgroup (P = 0.036). The difference in Lewis score between NSAID users and non-users was reproduced for the first and second proximal tertiles of the small bowel, but not for its distal third (P values of 0.036, 0.001 and 0.18, respectively). There was no statistical significant difference between the groups with regard to age or sex of the patients. CONCLUSION: The intestinal inflammatory involvement of SpA patients is more prominent in NSAID users for the proximal/mid small bowel, but not for its distal part. PMID:21448355

  16. Deleterious Thermal Effects Due To Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    NASA Technical Reports Server (NTRS)

    Moran, Robert P.

    2013-01-01

    A review of literature associated with Pebble Bed and Particle Bed reactor core research has revealed a systemic problem inherent to reactor core concepts which utilize randomized rather than structured coolant channel flow paths. For both the Pebble Bed and Particle Bed Reactor designs; case studies reveal that for indeterminate reasons, regions within the core would suffer from excessive heating leading to thermal runaway and localized fuel melting. A thermal Computational Fluid Dynamics model was utilized to verify that In both the Pebble Bed and Particle Bed Reactor concepts randomized coolant channel pathways combined with localized high temperature regions would work together to resist the flow of coolant diverting it away from where it is needed the most to cooler less resistive pathways where it is needed the least. In other words given the choice via randomized coolant pathways the reactor coolant will take the path of least resistance, and hot zones offer the highest resistance. Having identified the relationship between randomized coolant channel pathways and localized fuel melting it is now safe to assume that other reactor concepts that utilize randomized coolant pathways such as the foam core reactor are also susceptible to this phenomenon.

  17. Deleterious Thermal Effects due to Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    NASA Technical Reports Server (NTRS)

    Moran, Robert P.

    2013-01-01

    Reactor fuel rod surface area that is perpendicular to coolant flow direction (+S) i.e. perpendicular to the P creates areas of coolant stagnation leading to increased coolant temperatures resulting in localized changes in fluid properties. Changes in coolant fluid properties caused by minor increases in temperature lead to localized reductions in coolant mass flow rates leading to localized thermal instabilities. Reductions in coolant mass flow rates result in further increases in local temperatures exacerbating changes to coolant fluid properties leading to localized thermal runaway. Unchecked localized thermal runaway leads to localized fuel melting. Reactor designs with randomized flow paths are vulnerable to localized thermal instabilities, localized thermal runaway, and localized fuel melting.

  18. Upper limit of the rate and per generation effects of deleterious genomic mutations

    E-print Network

    Pfrender, Michael

    of Orthopedic Surgery and Basic Medical Sciences, University of Missouri ­ Kansas City, Kansas City, MO 64108 and Basic Medical Sciences, University of Missouri ­ Kansas City, 2411 Holmes Street. Room M3-C03, Kansas

  19. Trimetazidine Reverses Deleterious Effects of Ischemia-Reperfusion in the Isolated Perfused Pig Kidney Model

    Microsoft Academic Search

    Thierry Hauet; Denis Mothes; Jean-Michel Goujon; Thierry Germonville; Jean Claude Caritez; Michel Carretier; Michel Eugene; Jean-Paul Tillement

    1998-01-01

    Background: Delayed graft function has remained an important complication after renal transplantation. Methods: The purpose of this study was to evaluate Euro-Collins (EC) plus trimetazidine (TMZ) in comparison with standard EC solution after 24- or 48-hour cold storage. The normothermic isolated perfused pig kidney technique combined with proton nuclear magnetic spectroscopy was used. Results: The study verified that TMZ plus

  20. Deleterious Effects of High Concentrations of (-)-Epigallocatechin-3Gallate and Atorvastatin in Mice With Colon Inflammation

    Microsoft Academic Search

    Fei Guan; Anna B. Liu; Guangxun Li; Zhihong Yang; Yuhai Sun; Chung S. Yang; Jihyeung Ju

    2012-01-01

    Epigallocatechin-3-gallate (EGCG), atorvastatin (ATST), and their combination have been previously shown to inhibit colon carcinogenesis in animal models. We further investigated their inhibitory activities in azoxymethane (AOM) and dextran sulfate sodium (DSS)-treated Balb\\/cJ mice and CD-1 mice in 2 slightly different models. The mice were maintained on the AIN93M diet, or a similar diet containing 0.03%, 0.1%, or 0.3% EGCG;

  1. The expected effect of deleterious mutations on within-host adaptation of pathogens

    E-print Network

    Fonville, Judith M.

    2015-06-24

    of another mutation, 75 the landscape contains a fitness ridge. Such fitness valleys and ridges are 76 commonplace in virology, as will be illustrated with examples drawn from the 77 influenza field. 78 79 During zoonotic overspill infections of an avian...

  2. Deleterious Effects of Sleep-Disordered Breathing on the Heart and Vascular System

    Microsoft Academic Search

    H. Erhan Dincer; William O’Neill

    2006-01-01

    Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing, affecting 5–15% of the population. It is characterized by intermittent episodes of partial or complete obstruction of the upper airway during sleep that disrupts normal ventilation and sleep architecture, and is typically associated with excessive daytime sleepiness, snoring, and witnessed apneas. Patients with obstructive sleep apnea present risk

  3. Predictive ecology: systems approaches

    PubMed Central

    Evans, Matthew R.; Norris, Ken J.; Benton, Tim G.

    2012-01-01

    The world is experiencing significant, largely anthropogenically induced, environmental change. This will impact on the biological world and we need to be able to forecast its effects. In order to produce such forecasts, ecology needs to become more predictive—to develop the ability to understand how ecological systems will behave in future, changed, conditions. Further development of process-based models is required to allow such predictions to be made. Critical to the development of such models will be achieving a balance between the brute-force approach that naively attempts to include everything, and over simplification that throws out important heterogeneities at various levels. Central to this will be the recognition that individuals are the elementary particles of all ecological systems. As such it will be necessary to understand the effect of evolution on ecological systems, particularly when exposed to environmental change. However, insights from evolutionary biology will help the development of models even when data may be sparse. Process-based models are more common, and are used for forecasting, in other disciplines, e.g. climatology and molecular systems biology. Tools and techniques developed in these endeavours can be appropriated into ecological modelling, but it will also be necessary to develop the science of ecoinformatics along with approaches specific to ecological problems. The impetus for this effort should come from the demand coming from society to understand the effects of environmental change on the world and what might be performed to mitigate or adapt to them. PMID:22144379

  4. Environmental Effects on a Breeding Pair of Eagles- A Lesson on Habitats and Ecology

    NSDL National Science Digital Library

    Nancy Beuhner (Deubrook Area Schools)

    2008-08-01

    The purpose of this lesson is to simulate feeding practices of breeding eagles in a helpful or stressful situation to Grade 10 high school students. This activity works well near the end of a unit on Ecology. Students should have a basic understanding of biotic and abiotic factors, populations, niches, habitats and feeding relationships because once the activity is completed, students will be able to identify these characteristics of bald eagles. This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

  5. General Ecology

    NSDL National Science Digital Library

    This tutorial explains how environmental conditions and organism interactions determine animal and tree distribution and abundance. There are definitions of important ecological terms such as ecology, interactions, and abundance; descriptions of the environmental conditions needed for rainforests and how they provide habitat for many species; and an explanation of the spawning process. The tutorial also introduces food chain concepts and the unique ecology of riparian habitats. A quiz is also available.

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

    Microsoft Academic Search

    D. M. Tompkinsl; A. W. Sainsbury; P. Nettleton; D. Buxton; J. Gurnell

    2002-01-01

    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 pre- dation 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

  7. 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.

  8. 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

  9. Accumulation of Slightly Deleterious Mutations in the Mitochondrial Genome: a Hallmark of Animal Domestication

    PubMed Central

    Hughes, Austin L.

    2012-01-01

    The hypothesis that domestication lead to a relaxation of purifying selection on mitochondrial (mt) genomes was tested by comparative analysis of mt genes from dog, pig, chicken, and silkworm. The three vertebrate species showed mt genome phylogenies in which domestic and wild isolates were intermingled, whereas the domestic silkworm (Bombyx mori) formed a distinct cluster nested within its closest wild relative (B. mandarina). In spite of these differences in phylogenetic pattern, significantly greater proportions of nonsynonymous SNPs than of synonymous SNPs were unique to the domestic populations of all four species. Likewise, in all four species, significantly greater proportions of RNA-encoding SNPs than of synonymous SNPs were unique to the domestic populations. Thus, domestic populations were characterized by an excess of unique polymorphisms in two categories generally subject to purifying selection: nonsynonymous sites and RNA-encoding sites. Many of these unique polymorphisms thus seem likely to be slightly deleterious; the latter hypothesis was supported by the generally lower gene diversities of polymorphisms unique to domestic populations in comparison to those of polymorphisms shared by domestic and wild populations. PMID:23237775

  10. Partition dataset according to amino acid type improves the prediction of deleterious non-synonymous SNPs

    SciTech Connect

    Yang, Jing; Li, Yuan-Yuan [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China) [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China); Shanghai Center for Bioinformation Technology, Shanghai 200235 (China); Li, Yi-Xue, E-mail: yxli@sibs.ac.cn [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China) [School of Biotechnology, East China University of Science and Technology, Shanghai 200237 (China); Shanghai Center for Bioinformation Technology, Shanghai 200235 (China); Ye, Zhi-Qiang, E-mail: yezq@pkusz.edu.cn [Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055 (China) [Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, Peking University Shenzhen Graduate School, Shenzhen 518055 (China); Key Laboratory of Systems Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031 (China)

    2012-03-02

    Highlights: Black-Right-Pointing-Pointer Proper dataset partition can improve the prediction of deleterious nsSNPs. Black-Right-Pointing-Pointer Partition according to original residue type at nsSNP is a good criterion. Black-Right-Pointing-Pointer Similar strategy is supposed promising in other machine learning problems. -- Abstract: Many non-synonymous SNPs (nsSNPs) are associated with diseases, and numerous machine learning methods have been applied to train classifiers for sorting disease-associated nsSNPs from neutral ones. The continuously accumulated nsSNP data allows us to further explore better prediction approaches. In this work, we partitioned the training data into 20 subsets according to either original or substituted amino acid type at the nsSNP site. Using support vector machine (SVM), training classification models on each subset resulted in an overall accuracy of 76.3% or 74.9% depending on the two different partition criteria, while training on the whole dataset obtained an accuracy of only 72.6%. Moreover, the dataset was also randomly divided into 20 subsets, but the corresponding accuracy was only 73.2%. Our results demonstrated that partitioning the whole training dataset into subsets properly, i.e., according to the residue type at the nsSNP site, will improve the performance of the trained classifiers significantly, which should be valuable in developing better tools for predicting the disease-association of nsSNPs.

  11. A Selective Sweep on a Deleterious Mutation in CPT1A in Arctic Populations

    PubMed Central

    Clemente, Florian J.; Cardona, Alexia; Inchley, Charlotte E.; Peter, Benjamin M.; Jacobs, Guy; Pagani, Luca; Lawson, Daniel J.; Antão, Tiago; Vicente, Mário; Mitt, Mario; DeGiorgio, Michael; Faltyskova, Zuzana; Xue, Yali; Ayub, Qasim; Szpak, Michal; Mägi, Reedik; Eriksson, Anders; Manica, Andrea; Raghavan, Maanasa; Rasmussen, Morten; Rasmussen, Simon; Willerslev, Eske; Vidal-Puig, Antonio; Tyler-Smith, Chris; Villems, Richard; Nielsen, Rasmus; Metspalu, Mait; Malyarchuk, Boris; Derenko, Miroslava; Kivisild, Toomas

    2014-01-01

    Arctic populations live in an environment characterized by extreme cold and the absence of plant foods for much of the year and are likely to have undergone genetic adaptations to these environmental conditions in the time they have been living there. Genome-wide selection scans based on genotype data from native Siberians have previously highlighted a 3 Mb chromosome 11 region containing 79 protein-coding genes as the strongest candidates for positive selection in Northeast Siberians. However, it was not possible to determine which of the genes might be driving the selection signal. Here, using whole-genome high-coverage sequence data, we identified the most likely causative variant as a nonsynonymous G>A transition (rs80356779; c.1436C>T [p.Pro479Leu] on the reverse strand) in CPT1A, a key regulator of mitochondrial long-chain fatty-acid oxidation. Remarkably, the derived allele is associated with hypoketotic hypoglycemia and high infant mortality yet occurs at high frequency in Canadian and Greenland Inuits and was also found at 68% frequency in our Northeast Siberian sample. We provide evidence of one of the strongest selective sweeps reported in humans; this sweep has driven this variant to high frequency in circum-Arctic populations within the last 6–23 ka despite associated deleterious consequences, possibly as a result of the selective advantage it originally provided to either a high-fat diet or a cold environment. PMID:25449608

  12. Excess of de novo deleterious mutations in genes associated with glutamatergic systems in nonsyndromic intellectual disability.

    PubMed

    Hamdan, Fadi F; Gauthier, Julie; Araki, Yoichi; Lin, Da-Ting; Yoshizawa, Yuhki; Higashi, Kyohei; Park, A-Reum; Spiegelman, Dan; Dobrzeniecka, Sylvia; Piton, Amélie; Tomitori, Hideyuki; Daoud, Hussein; Massicotte, Christine; Henrion, Edouard; Diallo, Ousmane; Shekarabi, Masoud; Marineau, Claude; Shevell, Michael; Maranda, Bruno; Mitchell, Grant; Nadeau, Amélie; D'Anjou, Guy; Vanasse, Michel; Srour, Myriam; Lafrenière, Ronald G; Drapeau, Pierre; Lacaille, Jean Claude; Kim, Eunjoon; Lee, Jae-Ran; Igarashi, Kazuei; Huganir, Richard L; Rouleau, Guy A; Michaud, Jacques L

    2011-03-11

    Little is known about the genetics of nonsyndromic intellectual disability (NSID). We hypothesized that de novo mutations (DNMs) in synaptic genes explain an important fraction of sporadic NSID cases. In order to investigate this possibility, we sequenced 197 genes encoding glutamate receptors and a large subset of their known interacting proteins in 95 sporadic cases of NSID. We found 11 DNMs, including ten potentially deleterious mutations (three nonsense, two splicing, one frameshift, four missense) and one neutral mutation (silent) in eight different genes. Calculation of point-substitution DNM rates per functional and neutral site showed significant excess of functional DNMs compared to neutral ones. De novo truncating and/or splicing mutations in SYNGAP1, STXBP1, and SHANK3 were found in six patients and are likely to be pathogenic. De novo missense mutations were found in KIF1A, GRIN1, CACNG2, and EPB41L1. Functional studies showed that all these missense mutations affect protein function in cell culture systems, suggesting that they may be pathogenic. Sequencing these four genes in 50 additional sporadic cases of NSID identified a second DNM in GRIN1 (c.1679_1681dup/p.Ser560dup). This mutation also affects protein function, consistent with structural predictions. None of these mutations or any other DNMs were identified in these genes in 285 healthy controls. This study highlights the importance of the glutamate receptor complexes in NSID and further supports the role of DNMs in this disorder. PMID:21376300

  13. Excess of De Novo Deleterious Mutations in Genes Associated with Glutamatergic Systems in Nonsyndromic Intellectual Disability

    PubMed Central

    Hamdan, Fadi F.; Gauthier, Julie; Araki, Yoichi; Lin, Da-Ting; Yoshizawa, Yuhki; Higashi, Kyohei; Park, A-Reum; Spiegelman, Dan; Dobrzeniecka, Sylvia; Piton, Amélie; Tomitori, Hideyuki; Daoud, Hussein; Massicotte, Christine; Henrion, Edouard; Diallo, Ousmane; Shekarabi, Masoud; Marineau, Claude; Shevell, Michael; Maranda, Bruno; Mitchell, Grant; Nadeau, Amélie; D'Anjou, Guy; Vanasse, Michel; Srour, Myriam; Lafrenière, Ronald G.; Drapeau, Pierre; Lacaille, Jean Claude; Kim, Eunjoon; Lee, Jae-Ran; Igarashi, Kazuei; Huganir, Richard L.; Rouleau, Guy A.; Michaud, Jacques L.

    2011-01-01

    Little is known about the genetics of nonsyndromic intellectual disability (NSID). We hypothesized that de novo mutations (DNMs) in synaptic genes explain an important fraction of sporadic NSID cases. In order to investigate this possibility, we sequenced 197 genes encoding glutamate receptors and a large subset of their known interacting proteins in 95 sporadic cases of NSID. We found 11 DNMs, including ten potentially deleterious mutations (three nonsense, two splicing, one frameshift, four missense) and one neutral mutation (silent) in eight different genes. Calculation of point-substitution DNM rates per functional and neutral site showed significant excess of functional DNMs compared to neutral ones. De novo truncating and/or splicing mutations in SYNGAP1, STXBP1, and SHANK3 were found in six patients and are likely to be pathogenic. De novo missense mutations were found in KIF1A, GRIN1, CACNG2, and EPB41L1. Functional studies showed that all these missense mutations affect protein function in cell culture systems, suggesting that they may be pathogenic. Sequencing these four genes in 50 additional sporadic cases of NSID identified a second DNM in GRIN1 (c.1679_1681dup/p.Ser560dup). This mutation also affects protein function, consistent with structural predictions. None of these mutations or any other DNMs were identified in these genes in 285 healthy controls. This study highlights the importance of the glutamate receptor complexes in NSID and further supports the role of DNMs in this disorder. PMID:21376300

  14. Reduction of Lysyl Hydroxylase 3 Causes Deleterious Changes in the Deposition and Organization of Extracellular Matrix*

    PubMed Central

    Risteli, Maija; Ruotsalainen, Heli; Salo, Antti M.; Sormunen, Raija; Sipilä, Laura; Baker, Naomi L.; Lamandé, Shireen R.; Vimpari-Kauppinen, Leena; Myllylä, Raili

    2009-01-01

    Lysyl hydroxylase 3 (LH3) is a multifunctional enzyme possessing lysyl hydroxylase, collagen galactosyltransferase, and glucosyltransferase (GGT) activities. We report here an important role for LH3 in the organization of the extracellular matrix (ECM) and cytoskeleton. Deposition of ECM was affected in heterozygous LH3 knock-out mouse embryonic fibroblasts (MEF+/?) and in skin fibroblasts collected from a member of a Finnish epidermolysis bullosa simplex (EBS) family known to be deficient in GGT activity. We show the GGT deficiency to be due to a transcriptional defect in one LH3 allele. The ECM abnormalities also lead to defects in the arrangement of the cytoskeleton in both cell lines. Ultrastructural abnormalities were observed in the skin of heterozygous LH3 knock-out mice indicating that even a moderate decrease in LH3 has deleterious consequences in vivo. The LH3 null allele in the EBS family member and the resulting abnormalities in the organization of the extracellular matrix, similar to those found in MEF+/?, may explain the correlation between the severity of the phenotype and the decrease in GGT activity reported in this family. PMID:19696018

  15. An Application of a Mixed-Effects Location Scale Model for Analysis of Ecological Momentary Assessment (EMA) Data

    PubMed Central

    Hedeker, Donald; Mermelstein, Robin J.; Demirtas, Hakan

    2008-01-01

    Summary For longitudinal data, mixed models include random subject effects to indicate how subjects influence their responses over repeated assessments. The error variance and the variance of the random effects are usually considered to be homogeneous. These variance terms characterize the within-subjects (i.e., error variance) and between-subjects (i.e., random-effects variance) variation in the data. In studies using ecological momentary assessment (EMA), up to 30 or 40 observations are often obtained for each subject, and interest frequently centers around changes in the variances, both within and between subjects. In this article, we focus on an adolescent smoking study using EMA where interest is on characterizing changes in mood variation. We describe how covariates can influence the mood variances, and also extend the standard mixed model by adding a subject-level random effect to the within-subject variance specification. This permits subjects to have influence on the mean, or location, and variability, or (square of the) scale, of their mood responses. Additionally, we allow the location and scale random effects to be correlated. These mixed-effects location scale models have useful applications in many research areas where interest centers on the joint modeling of the mean and variance structure. PMID:17970819

  16. 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

  17. Soil Ecology

    NASA Astrophysics Data System (ADS)

    Killham, Ken

    1994-04-01

    Soil Ecology is designed to meet the increasing challenge faced by today's environmental scientists, ecologists, agriculturalists, and biotechnologists for an integrated approach to soil ecology. It emphasizes the interrelations among plants, animals, and microbes, by first establishing the fundamental physical and chemical properties of the soil habitat and then functionally characterizing the major components of the soil biota and some of their most important interactions. The fundamental principles underpinning soil ecology are established and this then enables an integrated approach to explore and understand the processes of soil nutrient (carbon, nitrogen, and phosphorus) cycling and the ecology of extreme soil conditions such as soil-water stress. Two of the most topical aspects of applied soil ecology are then selected. First, the ecology of soil pollution is examined, focusing on acid deposition and radionuclide pollution. Second, manipulation of soil ecology through biotechnology is discussed, illustrating the use of pesticides and microbial inocula in soils and pointing toward the future by considering the impact of genetically modified inocula on soil ecology.

  18. Predicting the impact of deleterious mutations in the protein kinase domain of FGFR2 in the context of function, structure, and pathogenesis--a bioinformatics approach.

    PubMed

    C, George Priya Doss; Rajith, B; Chakraborty, Chiranjib

    2013-08-01

    Fibroblast growth factor receptor 2 (FGFR2) controls a wide range of biological functions by regulating the cellular proliferation, survival, migration and differentiation. A growing body of preclinical data demonstrated that deregulation of the FGFR signalling through genetic modification was observed in various types of cancers. However, the extent to which genetic modifications interfere with gene regulation and their involvement in cancer susceptibility remains largely unknown. In this work, we performed in silico profiling of harmful non-synonymous single nucleotide polymorphisms (SNPs) in the protein kinase domain of FGFR2. Tolerance index, position-specific independent count score, change in free energy score (??G), Eris and FoldX indicated that seven mutations were found to be deleterious and may alter the protein function and structure. Furthermore, based on physico-chemical properties, two mutations K659N and R747H were found to be most deleterious in protein kinase domain and taken for further structural analysis. Docking study showed a complete loss of binding affinity followed by interference in hydrogen bonding and surrounding residues due to K659N and R747H mutations. In order to elucidate the mechanism behind the impact of mutation that can generate a ripple effect throughout the protein structure and ultimately affect the function, in-depth molecular dynamics simulation and principal component analysis were performed. The obtained results indicate that K659N and R747H mutations have a distinct effect on the dynamic behaviour of FGFR2 protein. Our strategy may be helpful for understanding SNP effects on proteins with function and their role in human genetic diseases and for the development of novel pharmacological strategies. PMID:23754559

  19. [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

  20. The Effects of Ecology-Based Summer Nature Education Program on Primary School Students' Environmental Knowledge, Environmental Affect and Responsible Environmental Behavior

    ERIC Educational Resources Information Center

    Erdogan, Mehmet

    2011-01-01

    The purpose of the study was to assess the effects of ecology-based nature education program on elementary school students' environmental knowledge, environmental affect, and responsible environmental behavior. A total number of 64 elementary school students including 26 females and 38 males who participated in summer natural education organized…

  1. Ecological Entomology (199I) 16, 1-9 The effect of host-plant quality on the survival of larvae and

    E-print Network

    Pierce, Naomi E.

    Ecological Entomology (199I) 16, 1-9 The effect of host-plant quality on the survival of larvae and unfertilized plants. 4.In the presence of ants, over a 10-day period, larvae on fertilized plants survived better than larvae on unfertilized plants. In the absence of ants larvae survived equally on fertilized

  2. Post-Doctoral Fellow Landscape Ecology / Movement Ecology

    E-print Network

    Haddad, Nick

    Post-Doctoral Fellow Landscape Ecology / Movement Ecology The Corridor Research Group Job to hire a Post-Doctoral Fellow to lead a large-scale experiment examining the effects of fragmentation Site, near Aiken, South Carolina. The Post-Doctoral Fellow will coordinate this collaborative research

  3. BRCA1/2 mutation analysis in 41 ovarian cell lines reveals only one functionally deleterious BRCA1 mutation.

    PubMed

    Stordal, Britta; Timms, Kirsten; Farrelly, Angela; Gallagher, Danielle; Busschots, Steven; Renaud, Mickaël; Thery, Julien; Williams, Deborah; Potter, Jennifer; Tran, Thanh; Korpanty, Greg; Cremona, Mattia; Carey, Mark; Li, Jie; Li, Yang; Aslan, Ozlem; O'Leary, John J; Mills, Gordon B; Hennessy, Bryan T

    2013-06-01

    Mutations in BRCA1/2 increase the risk of developing breast and ovarian cancer. Germline BRCA1/2 mutations occur in 8.6-13.7% of unselected epithelial ovarian cancers, somatic mutations are also frequent. BRCA1/2 mutated or dysfunctional cells may be sensitive to PARP inhibition by synthetic lethality. The aim of this study is to comprehensively characterise the BRCA1/2 status of a large panel of ovarian cancer cell lines available to the research community to assist in biomarker studies of novel drugs and in particular of PARP inhibitors. The BRCA1/2 genes were sequenced in 41 ovarian cell lines, mRNA expression of BRCA1/2 and gene methylation status of BRCA1 was also examined. The cytotoxicity of PARP inhibitors olaparib and veliparib was examined in 20 cell lines. The cell line SNU-251 has a deleterious BRCA1 mutation at 5564G > A, and is the only deleterious BRCA1/2 mutant in the panel. Two cell lines (UPN-251 and PEO1) had deleterious mutations as well as additional reversion mutations that restored the protein functionality. Heterozygous mutations in BRCA1/2 were relatively common, found in 14.6% of cell lines. BRCA1 was methylated in two cell lines (OVCAR8, A1847) and there was a corresponding decrease in gene expression. The BRCA1 methylated cell lines were more sensitive to PARP inhibition than wild-type cells. The SNU-251 deleterious mutant was more sensitive to PARP inhibition, but only in a long-term exposure to correct for its slow growth rate. Cell lines derived from metastatic disease are significantly more resistant to veliparib (2.0 fold p = 0.03) compared to those derived from primary tumours. Resistance to olaparib and veliparib was correlated Pearsons-R 0.5393, p = 0.0311. The incidence of BRCA1/2 deleterious mutations 1/41 cell lines derived from 33 different patients (3.0%) is much lower than the population incidence. The reversion mutations and high frequency of heterozygous mutations suggest that there is a selective pressure against BRCA1/2 in cell culture similar to the selective pressure seen in the clinic after treatment with chemotherapy. PARP inhibitors may be useful in patients with BRCA1 deleterious mutations or gene methylation. PMID:23415752

  4. Proportionally more deleterious genetic variation in European than in African populations.

    PubMed

    Lohmueller, Kirk E; Indap, Amit R; Schmidt, Steffen; Boyko, Adam R; Hernandez, Ryan D; Hubisz, Melissa J; Sninsky, John J; White, Thomas J; Sunyaev, Shamil R; Nielsen, Rasmus; Clark, Andrew G; Bustamante, Carlos D

    2008-02-21

    Quantifying the number of deleterious mutations per diploid human genome is of crucial concern to both evolutionary and medical geneticists. Here we combine genome-wide polymorphism data from PCR-based exon resequencing, comparative genomic data across mammalian species, and protein structure predictions to estimate the number of functionally consequential single-nucleotide polymorphisms (SNPs) carried by each of 15 African American (AA) and 20 European American (EA) individuals. We find that AAs show significantly higher levels of nucleotide heterozygosity than do EAs for all categories of functional SNPs considered, including synonymous, non-synonymous, predicted 'benign', predicted 'possibly damaging' and predicted 'probably damaging' SNPs. This result is wholly consistent with previous work showing higher overall levels of nucleotide variation in African populations than in Europeans. EA individuals, in contrast, have significantly more genotypes homozygous for the derived allele at synonymous and non-synonymous SNPs and for the damaging allele at 'probably damaging' SNPs than AAs do. For SNPs segregating only in one population or the other, the proportion of non-synonymous SNPs is significantly higher in the EA sample (55.4%) than in the AA sample (47.0%; P < 2.3 x 10(-37)). We observe a similar proportional excess of SNPs that are inferred to be 'probably damaging' (15.9% in EA; 12.1% in AA; P < 3.3 x 10(-11)). Using extensive simulations, we show that this excess proportion of segregating damaging alleles in Europeans is probably a consequence of a bottleneck that Europeans experienced at about the time of the migration out of Africa. PMID:18288194

  5. Prediction of deleterious non-synonymous single-nucleotide polymorphisms of human uridine diphosphate glucuronosyltransferase genes.

    PubMed

    Di, Yuan Ming; Chan, Eli; Wei, Ming Qian; Liu, Jun-Ping; Zhou, Shu-Feng

    2009-09-01

    UDP glucuronosyltransferases (UGTs) are an important class of Phase II enzymes involved in the metabolism and detoxification of numerous xenobiotics including therapeutic drugs and endogenous compounds (e.g. bilirubin). To date, there are 21 human UGT genes identified, and most of them contain single-nucleotide polymorphisms (SNPs). Non-synonymous SNPs (nsSNPs) of the human UGT genes may cause absent or reduced enzyme activity and polymorphisms of UGT have been found to be closely related to altered drug clearance and/or drug response, hyperbilirubinemia, Gilbert's syndrome, and Crigler-Najjar syndrome. However, it is unlikely to study the functional impact of all identified nsSNPs in humans using laboratory approach due to its giant number. We have investigated the potential for bioinformatics approach for the prediction of phenotype based on known nsSNPs. We have identified a total of 248 nsSNPs from human UGT genes. The two algorithms tools, sorting intolerant from tolerant (SIFT) and polymorphism phenotyping (PolyPhen), were used to predict the impact of these nsSNPs on protein function. SIFT classified 35.5% of the UGT nsSNPs as "deleterious"; while PolyPhen identified 46.0% of the UGT nsSNPs as "potentially damaging" and "damaging". The results from the two algorithms were highly associated. Among 63 functionally characterized nsSNPs in the UGTs, 24 showed altered enzyme expression/activities and 45 were associated with disease susceptibility. SIFT and Polyphen had a correct prediction rate of 57.1% and 66.7%, respectively. These findings demonstrate the potential use of bioinformatics techniques to predict genotype-phenotype relationships which may constitute the basis for future functional studies. PMID:19572200

  6. 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.

  7. The Ecological Impact of Biofuels

    E-print Network

    Kammen, Daniel M.

    The Ecological Impact of Biofuels Joseph E. Fargione,1 Richard J. Plevin,2 and Jason D. Hill3 1 land-use change Abstract The ecological impact of biofuels is mediated through their effects on land, air, and water. In 2008, about 33.3 million ha were used to produce food- based biofuels

  8. 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…

  9. Journal of Animal Ecology 2003

    E-print Network

    Richner, Heinz

    Journal of Animal Ecology 2003 72, 633­639 © 2003 British Ecological Society Blackwell Publishing, if parasite infestation levels fluctuate over the nestling period, parasitized young may show reduced growth- tionships, and to investigate the effect of parasites on host development over the entire growing period

  10. 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

    2015-06-01

    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. 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. 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. 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. 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

  11. Effects of wind energy development on nesting ecology of greater prairie-chickens in fragmented grasslands.

    PubMed

    McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

    2014-08-01

    Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before-after control-impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (? = 0.03, 95% CI = -1.2-1.3) or nest survival (? = -0.3, 95% CI = -0.6-0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. PMID:24628394

  12. Breeding ecology of Horned Puffins (Fratercula corniculata) in Alaska: annual variation and effects of El Niño

    USGS Publications Warehouse

    Harding, A.M.A.; Piatt, J.F.; Hamer, K.C.

    2003-01-01

    Both within and among seabird species, different aspects of breeding biology may respond to changes in prey availability in distinct ways, and the identification of species-specific breeding parameters that are sensitive to food availability is useful for monitoring purposes. We present data from a 5-year study (1995?1999) of the breeding ecology of Horned Puffins (Fratercula corniculata) in Alaska. The El Niño ? Southern Oscillation event of 1997?1998 provided an opportunity to examine the sensitivity of various breeding parameters to a reduction in prey availability caused by the anomalous oceanographic conditions of 1998. Horned Puffins were able to maintain high fledging success (83?97%) over the 5 years of the study, despite the poor local feeding conditions in 1998. The rate of increase in chick mass was lowest in 1998, and evidence suggests that chicks also fledged at the youngest ages in that year. The impacts of reduced food availability on growth varied among body structures, suggesting differential allocation of energy and nutrients. There was no variation among years in either chick diet or the mass of food loads delivered by adults. We suggest that rates of chick growth, specifically mass increase, may be a good parameter to measure for use in monitoring Horned Puffins.

  13. Effects of aircraft noise and sonic booms on fish and wildlife: results of a survey of u. s. fish and wildlife service endangered species and ecological services field offices, refuges, hatcheries, and research centers

    Microsoft Academic Search

    D. N. Gladwin; D. A. Asherin; K. M. Manci

    1988-01-01

    The National Ecology Research Center (Center), as part of an ongoing research study on the effects of low-altitude aircraft operations on fish and wildlife, conducted a survey in January 1987 of all U.S. Fish and Wildlife Service (Service) regional directors, research center directors, Ecological Services and Endangered Species field offices supervisors, refuge manager, and hatchery manager. The objective of the

  14. 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

  15. The Landscape Ecology of Invasive Spread

    Microsoft Academic Search

    2002-01-01

    Although habitat loss, fragmentation, and invasive species collectively pose the greatest threats to biodiversity, little theoretical or empirical research has addressed the effects of landscape structure—or spa- tial pattern more generally—on the spread of invasive species. Landscape ecology is the study of how spatial pattern affects ecological process. Thus, a landscape ecology of invasive spread involves understanding how spatial pattern,

  16. Phytoplankton Ecology

    NSDL National Science Digital Library

    This site describes phytoplankton ecology research by marine ecologists at Mote Marine Laboratory (MML), an independent, nonprofit research organization based in Sarasota, Florida. The emphasis of MML's phytoplankton ecology research is the photophysiology of marine algae -- with recent emphasis on the ability to predict and possibly mitigate blooms of the toxic marine dinoflagellate, Gymnodinium breve. The no-frills phytoplankton ecology homepage describes research and offers data (maps, figures, tables) from 1998 and 1999 projects on Red Tide transects, Nutrient and chlorophyll concentrations, and Ecology and Oceanography of Harmful Algal Blooms (ECOHAB) transect data, among several others. The site also offers general information on Red Tides, Red Tide conditions in Southwest Florida, a chronology of historic Red Tide events, and links to related resources.

  17. Numerical ecology validates a biogeographical distribution and gender-based effect on mucosa-associated bacteria along the human colon

    Microsoft Academic Search

    Daniel Aguirre de Cárcer; Páraic Ó Cuív; Tingting Wang; Seungha Kang; Daniel Worthley; Vicki Whitehall; Iain Gordon; Chris McSweeney; Barbara Leggett; Mark Morrison

    2011-01-01

    We applied constrained ordination numerical ecology methods to data produced with a human intestinal tract-specific phylogenetic microarray (the Aus-HIT Chip) to examine the microbial diversity associated with matched biopsy tissue samples taken from the caecum, transverse colon, sigmoid colon and rectum of 10 healthy patients. Consistent with previous studies, the profiles revealed a marked intersubject variability; however, the numerical ecology

  18. Campus Ecology

    NSDL National Science Digital Library

    National Wildlife Federation

    This website from the National Wildlife Federation showcases environmental conservation projects that have been successfully undertaken by various universities. The site features example projects and resources for doing your own campus project. Topics include building design, energy, environmental literacy, habitat restoration, water, transportation and waste reduction. Links to the online Campus Ecology Yearbook and the Campus Ecology Research Station and other resources are also included.

  19. Geographical Distribution of Adolescent Body Height with Respect to Effective Day Length in Japan: An Ecological Analysis

    PubMed Central

    Yokoya, Masana; Shimizu, Hideyasu; Higuchi, Yukito

    2012-01-01

    The height of Japanese youth raised in the northern region tends to be greater than that of youth raised in the southern region; therefore, a geographical gradient in youth body height exists. Although this gradient has existed for about 100 years, the reasons for it remain unclear. Consideration of the nutritional improvement, economic growth, and intense migration that has occurred in this period indicates that it is probably the result of environmental rather than nutritional or genetic factors. To identify possible environmental factors, ecological analysis of prefecture-level data on the body size of 8- to 17-year-old youth averaged over a 13-year period (1996 to 2008) and Japanese mesh climatic data on the climatic variables of temperature, solar radiation, and effective day length (duration of photoperiod exceeding the threshold of light intensity) was performed. The geographical distribution of the standardized height of Japanese adolescents was found to be inversely correlated to a great extent with the distribution of effective day length at a light intensity greater than 4000 lx. The results of multiple regression analysis of effective day length, temperature, and weight (as an index of food intake) indicated that a combination of effective day length and weight was statistically significant as predictors of height in early adolescence; however, only effective day length was statistically significant as a predictor of height in late adolescence. Day length may affect height by affecting the secretion of melatonin, a hormone that inhibits sexual and skeletal maturation, which in turn induces increases in height. By affecting melatonin production, regional differences in the duration of the photoperiod may lead to regional differences in height. Exposure to light intensity greater than 4000 lx appears to be the threshold at which light intensity begins to affect the melatonin secretion of humans who spend much of their time indoors. PMID:23227226

  20. Hydrothermal carbonization of biomass residues: mass spectrometric characterization for ecological effects in the soil-plant system.

    PubMed

    Jandl, Gerald; Eckhardt, Kai-Uwe; Bargmann, Inge; Kücke, Martin; Greef, Jörg-Michael; Knicker, Heike; Leinweber, Peter

    2013-01-01

    Hydrochars, technically manufactured by hydrothermal carbonization (HTC) of biomass residues, are recently tested in high numbers for their suitability as feedstock for bioenergy production, the bioproduct industry, and as long-term carbon storage in soil, but ecological effects in the soil-plant system are not sufficiently known. Therefore, we investigated the influence of different biomass residues and process duration on the molecular composition of hydrochars, and how hydrochar addition to soils affected the germination of spring barley ( L.) seeds. Samples from biomass residues and the corresponding hydrochars were analyzed by pyrolysis-field ionization mass spectrometry (Py-FIMS) and gaseous emissions from the germination experiments with different soil-hydrochar mixtures by gas chromatography/mass spectrometry (GC/MS). The molecular-level characterization of various hydrochars by Py-FIMS clearly showed that the kind of biomass residue influenced the chemical composition of the corresponding hydrochars more strongly than the process duration. In addition to various detected possible toxic substances, two independent mass spectrometric methods (Py-FIMS and GC/MS) indicated long C-chain aliphatic compounds which are typically degraded to the C-unit ethylene that can evoke phytotoxic effects in high concentrations. This showed for the first time possible chemical compounds to explain toxic effects of hydrochars on plant growth. It is concluded that the HTC process did not result in a consistent product with defined chemical composition. Furthermore, possible toxic effects urgently need to be investigated for each individual hydrochar to assess effects on the soil organic matter composition and the soil biota before hydrochar applications as an amendment on agricultural soils. PMID:23673755

  1. Effect of sulfate and lactate loading rates on the respiration process and microbial population changes measured by ecological indices.

    PubMed

    García-Saucedo, C; Fernández, F J; Cuervo-López, F M; Gómez, J

    2015-01-01

    In a sulfate reducing process, increasing loading rates and sulfide accumulation may induce population changes resulting in decreasing effectiveness of the process. Thus, the relationship between microbial metabolism changes and population dynamics was studied. An upflow anaerobic sludge blanket reactor was operated at different sulfate loading rates (SLR), from 290 to 981 mg SO4 - S/L d at a constant carbon/sulfur ratio of 0.75. When the SLR was increased, the total organic carbon and sulfate consumption efficiencies decreased to nearly 30% and 25%, respectively. The acetate and propionate yields increased with increasing SLR and 385 ± 7 mg sulfide-S/L d was reached. The ecological indices, determined by random amplified polymorphic DNA and denaturing gradient gel electrophoresis techniques, diversity and evenness were found to be constant, and similarity coefficient values remained higher than 76%. The results suggest that the microbial population changes were negligible compared with metabolic changes when SLR was increased. The sulfide accumulation did not modify the microbial diversity. The sequencing of 16S rRNA genes showed strains related to sulfate reducing, fermentation, and methanogenesis processes. The results indicated that the decreasing of effectiveness, under the experimental conditions tested, was dependent more on operational parameters than microbial changes. PMID:25607675

  2. Antimicrobial Active Clothes Display No Adverse Effects on the Ecological Balance of the Healthy Human Skin Microflora

    PubMed Central

    Hoefer, Dirk; Hammer, Timo R.

    2011-01-01

    The progressive public use of antimicrobial clothes has raised issues concerning skin health. A placebo-controlled side-to-side study was run with antimicrobial clothes versus fabrics of similar structure but minus the antimicrobial activity, to evaluate possible adverse effects on the healthy skin microflora. Sixty volunteers were enrolled. Each participant received a set of form-fitting T-shirts constructed in 2 halves: an antibacterial half, displaying activities of 3–5 log-step reductions due to silver-finishes or silver-loaded fibres and a nonantibacterial control side. The microflora of the scapular skin was analyzed weekly for opportunistic and pathogenic microorganisms over six weeks. The antibacterial halves did not disturb the microflora in number or composition, whereas a silver-containing deodorant displayed a short-term disturbance. Furthermore, parameters of skin morphology and function (TEWL, pH, moisture) did not show any significant shifts. In summary, antimicrobial clothes did not show adverse effects on the ecological balance of the healthy skin microflora. PMID:22363849

  3. Ecological risk assessment in a large river-reservoir. 7: Environmental contaminant accumulation and effects in great blue heron

    SciTech Connect

    Halbrook, R.S. [Southern Illinois Univ., Carbondale, IL (United States); Brewer, R.L. Jr.; Buehler, D.A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Forestry, Wildlife and Fisheries

    1999-04-01

    Past plant operations and waste disposal on the Oak Ridge Reservation (ORR) have introduced an assortment of potentially harmful contaminants into the surrounding environment. Elevated concentrations of mercury (Hg) and PCBs have been found in fish collected from aquatic systems on the ORR, and a screening level risk assessment has identified piscivorous wildlife downstream from the ORR as being at risk. As a component of an ecological risk assessment of a large river-reservoir system, the great blue heron (Ardea herodias) was chosen as an endpoint species to evaluate potential adverse effects of contaminants on piscivorous wildlife using aquatic systems on or downstream of the ORR. Eggs and chick liver, muscle, and fat samples were collected from two heron colonies located on and two colonies located off the ORR. Samples were analyzed for PCBs, mercury, chromium, and arsenic to determine if differences existed among colonies. Mean mercury and PCB concentrations were greater in eggs and chick tissues collected from colonies located on the ORR. However, no biologically significant differences were observed in fecundity or in egg physical measurements or chick physiological measurements between study locations. The results of this study do not indicate that the contaminant burdens in great blue heron chicks and eggs have a detrimental effect on heron populations utilizing aquatic habitats on the ORR.

  4. Investigations on the Effects of Dietary Essential Oils and Different Husbandry Conditions on the Gut Ecology in Piglets after Weaning

    PubMed Central

    Janczyk, P.; Pieper, R.; Urubschurov, V.; Wendler, K. R.; Souffrant, W. B.

    2009-01-01

    Essential oils (EO) are being considered as possible alternatives to in-feed antibiotic growth promoters in pig nutrition. The effects of an EO mixture consisting of limonene, eugenol and pinene (10.0, 2.0, and 4.8 mg/kg diet, resp.) on gut physiology and ecology were studied in piglets. The experiment was conducted at low (commercial farm) and high hygienic conditions (experimental farm), to elucidate interactions between EO supplementation and husbandry methods. Piglets were weaned at 28 days of age, when they were offered either a control diet (C) or C with EO. Four piglets were sacrificed in each group on day 29, 30, 33 and 39. Digesta from the third distal part of the small intestine and from the colon were sampled and analysed for pH, dry matter, lactic acid, short chain fatty acids and ammonia concentrations. Enterobacteria, enterococci, lactobacilli and yeast counts were obtained by plating. Genomic DNA was extracted from digesta and polymerase chain reaction—denaturing gradient gel electrophoresis was performed. Individual microbial communities were identified at each farm. Age affected the intestinal parameters. No effects of the EO with exception for a significant reduction in colon bacterial diversity at 39 days of age could be recorded at experimental farm. PMID:20016670

  5. 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.

  6. 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...

  7. The ecology of infectious disease: Effects of host diversity and community composition

    E-print Network

    prevalence of ticks by diluting the effects of the ubiquitous white-footed mouse (Peromyscus leucopus by diluting the effects of the most competent disease reservoir, the ubiquitous white-footed mouse (Peromyscus leucopus). As habitats are degraded by frag- mentation or other anthropogenic forces, some members

  8. Identifying Hazards in Complex Ecological Systems. Part 2: Infection Modes and Effects Analysis for Biological Invasions

    Microsoft Academic Search

    Keith R. Hayes

    2002-01-01

    This paper describes a rigorous and systematic hazard analysis, called infection modes and effects analysis (named after its industrial counterpart failure modes and effect analysis (FMEA)), which was used to investigate the potential spread of marine organisms by human vectors. The analysis was conducted using small craft as a model system and implemented through nine workshops targeted at owners and

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

    E-print Network

    . 31(1): 10Ð14 (2002) ABSTRACT This research tested the effects of paper birch, Betula papyrifera leucostigma, Betula papyrifera, whitemarked tussock moth, condensed tannin, paper birch CONDENSED TANNINS. Smith), to evaluate the effects of paper birch, Betula papyrifera Marshall, condensed tannin on in- sect

  10. [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

  11. Experimental terrestrial soil-core microcosm test protocol. A method for measuring the potential ecological effects, fate, and transport of chemicals in terrestrial ecosystems

    SciTech Connect

    Van Voris, P.; Tolle, D.A.; Arthur, M.F.

    1985-06-01

    In order to protect the environment properly and have a realistic appraisal of how a chemical will act in the environment, tests of ecological effects and chemical fate must be performed on complex assemblages of biotic and abiotic components (i.e., microcosms) as well as single species. This protocol is one which could be added to a series of tests recently developed as guidelines for Section 4 of the Toxic Substances Control Act (P.L. 94-469; U.S.C., Section 2601-2629). The terrestrial soil-core microcosm is designed to supply site-specific and possibly regional information on the probable chemical fate and ecological effects resulting from release of a chemical substance to a terrestrial ecosystem. The EPA will use the data resulting from this test system to compare the potential hazards of a chemical with others that have been previously evaluated.

  12. Hydrologic and Ecological Effects of Watershed Urbanization: Implication for Watershed Management in Hillslope Regions

    E-print Network

    Sung, Chan Yong

    2011-08-08

    = 0.764) ........................................ 73 1 CHAPTER I INTRODUCTION Background Riparian forests buffer harmful effects from surrounding areas (Basnyat et al., 2000; Groffman et al., 2002; Mitsch and Gosselink, 2007...

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

    EPA Science Inventory

    While neutral theory and models have stimulated considerable literature, less well investigated is the effect of topology on neutral metacommunity model simulations. We implemented a neutral metacommunity model using two different stream network topologies, a widely branched netw...

  14. 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...

  15. Effects of Wind Energy Development on Nesting Ecology of Greater Prairie-Chickens in Fragmented Grasslands

    PubMed Central

    McNew, Lance B; Hunt, Lyla M; Gregory, Andrew J; Wisely, Samantha M; Sandercock, Brett K

    2014-01-01

    Wind energy is targeted to meet 20% of U.S. energy needs by 2030, but new sites for development of renewable energy may overlap with important habitats of declining populations of grassland birds. Greater Prairie-Chickens (Tympanuchus cupido) are an obligate grassland bird species predicted to respond negatively to energy development. We used a modified before–after control–impact design to test for impacts of a wind energy development on the reproductive ecology of prairie-chickens in a 5-year study. We located 59 and 185 nests before and after development, respectively, of a 201 MW wind energy facility in Greater Prairie-Chicken nesting habitat and assessed nest site selection and nest survival relative to proximity to wind energy infrastructure and habitat conditions. Proximity to turbines did not negatively affect nest site selection (? = 0.03, 95% CI = ?1.2–1.3) or nest survival (? = ?0.3, 95% CI = ?0.6–0.1). Instead, nest site selection and survival were strongly related to vegetative cover and other local conditions determined by management for cattle production. Integration of our project results with previous reports of behavioral avoidance of oil and gas facilities by other species of prairie grouse suggests new avenues for research to mitigate impacts of energy development. Efectos del Desarrollo de la Energía Eólica sobre la Ecología de Anidación de Gallinas de la Gran Pradera en Pastizales Fragmentados Resumen Se calcula que la energía eólica aportará el 20% de las necesidades energéticas de los Estados Unidos para el 2030, pero nuevos sitios para el desarrollo de energía renovable pueden traslaparse con hábitats importantes de poblaciones declinantes de aves de pastizal. La gallina de la Gran Pradera (Tympanuchus cupido) es una especie de ave obligada de pastizal que se pronostica responderá negativamente al desarrollo energético. Usamos un diseño ADCI modificado para probar los impactos del desarrollo de la energía eólica sobre la ecología reproductiva de las gallinas en un estudio de 5 años. Ubicamos 59 y 185 nidos antes y después del desarrollo, respectivamente, de una instalación de energía eólica de 201 MW en el hábitat de anidación de las gallinas y estudiamos la selección de sitio de anidación y la supervivencia de nidos en relación con la proximidad a la infraestructura y las condiciones de hábitat. La proximidad con las turbinas no afectó negativamente a la selección de sitios de anidación (? = -0.3, 95% CI = -0.6–0.1). En su lugar, la selección de sitios de anidación y la supervivencia estuvieron fuertemente relacionadas con la cobertura vegetal y otras condiciones locales determinadas por el manejo de la producción de ganado. La integración de los resultados de nuestro proyecto con reportes previos de la evitación conductual de instalaciones de petróleo y gas por otras especies de pastizales sugiere nuevas vías para que la investigación mitigue los impactos del desarrollo energético. PMID:24628394

  16. Ecological effects of combined pollution associated with e-waste recycling on the composition and diversity of soil microbial communities.

    PubMed

    Liu, Jun; He, Xiao-Xin; Lin, Xue-Rui; Chen, Wen-Ce; Zhou, Qi-Xing; Shu, Wen-Sheng; Huang, Li-Nan

    2015-06-01

    The crude processing of electronic waste (e-waste) has led to serious contamination in soils. While microorganisms may play a key role in remediation of the contaminated soils, the ecological effects of combined pollution (heavy metals, polychlorinated biphenyls, and polybrominated diphenyl ethers) on the composition and diversity of microbial communities remain unknown. In this study, a suite of e-waste contaminated soils were collected from Guiyu, China, and the indigenous microbial assemblages were profiled by 16S rRNA high-throughput sequencing and clone library analysis. Our data revealed significant differences in microbial taxonomic composition between the contaminated and the reference soils, with Proteobacteria, Acidobacteria, Bacteroidetes, and Firmicutes dominating the e-waste-affected communities. Genera previously identified as organic pollutants-degrading bacteria, such as Acinetobacter, Pseudomonas, and Alcanivorax, were frequently detected. Canonical correspondence analysis revealed that approximately 70% of the observed variation in microbial assemblages in the contaminated soils was explained by eight environmental variables (including soil physiochemical parameters and organic pollutants) together, among which moisture content, decabromodiphenyl ether (BDE-209), and copper were the major factors. These results provide the first detailed phylogenetic look at the microbial communities in e-waste contaminated soils, demonstrating that the complex combined pollution resulting from improper e-waste recycling may significantly alter soil microbiota. PMID:25919421

  17. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan. Topical report, October 1990--August 1992

    SciTech Connect

    Rastorfer, J.R. [Chicago State Univ., IL (United States). Dept. of Biological Sciences; Van Dyke, G.D.; Zellmer, S.D.; Wilkey, P.L. [Argonne National Lab., IL (United States)

    1995-04-01

    This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth wetland sites mapped Lenawee soils were selected in Midland County, Michigan: Site 1, a younger stand subjected to recent selective logging, and Site 2, a more mature stand. The collection of ecological data to analyze plant succession on the right-of-way (ROW) and the effects of the developing ROW plant communities on adjacent forest communities was initiated in 1989. Cover class estimates were made for understory and ROW plant species on the basis of 1 {times} 1{minus}m quadrats. Individual stem diameters and species counts were recorded for overstory plants in 10{minus}m quadrats. Although long-term studies have not been completed, firm baseline data were established for comparative analyses with future sampling. Current data indicate that vegetation became well-established on the ROW within one year and subsequently increased in coverage. About 65% of the species were wetland indicators, and the dominants included seeded and natural invading species; nevertheless, some elements of the original flora regenerated and persist. The plants of the ecotone understories of both sites changed from their original composition as a result of the installation of the gas pipeline. Although some forest species persist at both sites, the ecotone of Site I was influenced more by the seeded species, whereas the natural invaders were more important at Site 2.

  18. Biodegradation of dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) with plant and nutrients and their effects on the microbial ecological kinetics.

    PubMed

    Sun, Guangdong; Zhang, Xu; Hu, Qing; Zhang, Heqing; Zhang, Dayi; Li, Guanghe

    2015-02-01

    Four pilot-scale test mesocosms were conducted for the remediation of organochlorine pesticides (OCPs)-contaminated aged soil. The results indicate that the effects on degradation of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were in the following order: nutrients/plant bioaugmentation (81.18 % for HCHs; 85.4 % for DDTs) > nutrients bioaugmentation > plant bioaugmentation > only adding water > control, and nutrients/plant bioaugmentation greatly enhanced the degradation of HCHs (81.18 %) and DDTs (85.4 %). The bacterial community structure, diversity and composition were assessed by 454-pyrosequencing of 16S recombinant RNA (rRNA), whereas the abundance of linA gene was determined by quantitative polymerase chain reaction. Distinct differences in bacterial community composition, structure, and diversity were a function of remediation procedure. Predictability of HCH/DDT degradation in soils was also investigated. A positive correlation between linA gene abundance and the removal ratio of HCHs was indicated by correlation analyses. A similar relationship was also confirmed between the degradation of HCHs/DDTs and the abundance of some assemblages (Gammaproteobacteria and Flavobacteria). Our results offer microbial ecological insight into the degradation of HCHs and DDTs in aged contaminated soil, which is helpful for the intensification of bioremediation through modifying plant-microbe patterns, and cessation of costly and time-consuming assays. PMID:25213654

  19. Dispositional Drinking Motives: Associations with Appraised Alcohol Effects and Alcohol Consumption in an Ecological Momentary Assessment Investigation

    PubMed Central

    Piasecki, Thomas M.; Cooper, M. Lynne; Wood, Phillip K.; Sher, Kenneth J.; Shiffman, Saul; Heath, Andrew C.

    2014-01-01

    Alcohol use can be understood as a strategic behavior, such that people choose to drink based on the anticipated affective changes produced by drinking relative to those produced by alternative behaviors. This study investigated whether people who report drinking for specific reasons via the Drinking Motives Questionnaire-Revised (DMQ-R, Cooper, 1994) actually experience the alcohol effects they purportedly seek. As a secondary goal, we examined relations between drinking motives and indices of the amount of alcohol consumed. Data were drawn from 3,272 drinking episodes logged by 393 community-recruited drinkers during a 21-day Ecological Momentary Assessment investigation. After accounting for selected covariates, DMQ-R enhancement motives uniquely predicted real-time reports of enhanced drinking pleasure. DMQR coping motives were associated with reports of increased drinking-contingent relief and punishment. Enhancement motives uniquely predicted consuming more drinks per episode and higher peak intra-episode estimated blood alcohol concentration. The findings extend the evidence for the validity of the DMQ-R motive scores by demonstrating that internal drinking motives (enhancement and coping) are related to the experienced outcomes of drinking in the manner anticipated by theory. PMID:24274049

  20. METHODS FOR DETERMINING EXPOSURE TO AND POTENTIAL ECOLOGICAL EFFECTS OF GENE FLOW FROM GENETICALLY MODIFIED CROPS TO COMPATIBLE RELATIVES

    EPA Science Inventory

    SCIENCE QUESTIONS: -Does gene flow occur from genetically modified (GM) crop plants to compatible plants? -How can it be measured? -Are there ecological consequences of GM crop gene flow to plant communities? RESEARCH: The objectives ...

  1. Overview: the impact of avermectins on pastureland ecology.

    PubMed

    Strong, L

    1993-06-01

    Avermectins, a relatively new class of broad spectrum pesticides, are used widely to control livestock parasites. Following treatment, avermectins are eliminated in the livestock faeces where they also have a wide range of harmful affects upon certain characteristic insects that breed in dung, few of which are pests, and many of which are beneficial. The effects range from acute toxicity in larvae and adults, through disruption of metamorphosis, to interference with reproduction. Different methods of drug administration lead to different concentrations of drug residues in the faeces, which in turn influence the responses of non-target organisms. Higher Diptera are particularly sensitive to drug residues and show a wide range of responses from death of larvae to developmental abnormalities in the adults. Larvae and immature adults of Coleoptera show some mortality in the dung of recently treated animals, while delayed effects upon reproduction and physiology have been observed in adults feeding on dung at longer post-treatment times. Although the impact of lethal doses has been described in some species, the effects of sub-lethal doses have hardly been recognised at the present time. Correlated with the deleterious effect upon dung-breeding insects, a retardation in the rate of loss of biomass of dung pats from avermectin-treated cattle has been observed following the various forms of drug administration. Differences in methodology, inappropriate statistics, and/or extremes of climatic conditions prevailing at the time of testing, explain the results of those studies where such delays have not been observed. It is short-sighted to consider only dung dispersal in relation to avermectin usage, a practice that overlooks the impact on the insects themselves and their diverse roles in pastureland ecology. PMID:8346644

  2. Short-rotation plantations of balsam poplars, aspen and willows on former arable land in the Federal Republic of Germany. III. Soil ecological effects

    Microsoft Academic Search

    A Jug; F Makeschin; K. E Rehfuess; C Hofmann-Schielle

    1999-01-01

    As part of an interdisciplinary research program, soil ecological effects of short-rotation forestry were studied at three experimental plantations on former arable soils in southern (Abbachhof=ABB), central (Canstein=CAN) and northern (Wildeshausen=WIL) Germany between 1983 and 1996. The methodological approach included a partly factorial fertilization trial with the nutrients N, P, K, Mg and Ca. Representative treatments and plots of those

  3. Potential effects of large linear pipeline construction on soil and vegetation in ecologically fragile regions.

    PubMed

    Xiao, Jun; Wang, Ya-Feng; Shi, Peng; Yang, Lei; Chen, Li-Ding

    2014-11-01

    Long-distance pipeline construction results in marked human disturbance of the regional ecosystem and brings into question the safety of pipeline construction with respect to the environment. Thus, the direct environmental impact and proper handling of such large projects have received much attention. The potential environmental effects, however, have not been fully addressed, particularly for large linear pipeline projects, and the threshold of such effects is unclear. In this study, two typical eco-fragile areas in western China, where large linear construction projects have been conducted, were chosen as the case study areas. Soil quality indices (SQI) and vegetation indices (VI), representing the most important potential effects, were used to analyze the scope of the effect of large pipeline construction on the surrounding environment. These two indices in different buffer zones along the pipeline were compared against the background values. The analysis resulted in three main findings. First, pipeline construction continues to influence the nearby eco-environment even after a 4-year recovery period. During this period, the effect on vegetation due to pipeline construction reaches 300 m beyond the working area, and is much larger in distance than the effect on soil, which is mainly confined to within 30 m either side of the pipeline, indicating that vegetation is more sensitive than soil to this type of human disturbance. However, the effect may not reach beyond 500 m from the pipeline. Second, the scope of the effect in terms of distance on vegetation may also be determined by the frequency of disturbance and the intensity of the pipeline construction. The greater the number of pipelines in an area, the higher the construction intensity and the more frequent the disturbance. Frequent disturbance may expand the effect on vegetation on both sides of the pipeline, but not on soil quality. Third, the construction may eliminate the stable, resident plant community. During the recovery period, the plant community in the work area of the pipeline is replaced by some species that are rare or uncommon in the resident plant community because of human disturbance, thereby increasing the plant diversity in the work area. In terms of plant succession, the duration of the recovery period has a direct effect on the composition and structure of the plant community. The findings provide a theoretical basis and scientific foundation for improving the environmental impact assessment (EIA) of oil and gas pipeline construction as it pertains to the desert steppe ecosystem, and provide a reference point for recovery and management of the eco-environment during the pipeline construction period. PMID:25112841

  4. The effect of physical drivers on ecosystem indices derived from ecological network analysis: Comparison across estuarine ecosystems

    NASA Astrophysics Data System (ADS)

    Niquil, Nathalie; Chaumillon, Eric; Johnson, Galen A.; Bertin, Xavier; Grami, Boutheina; David, Valérie; Bacher, Cédric; Asmus, Harald; Baird, Daniel; Asmus, Ragnhild

    2012-08-01

    The structure and function of estuarine food webs change in response to both natural and anthropogenic stresses. The construction of quantitative food webs and their analysis by means of Ecological Network Analysis provides outputs that have been used in many studies to assess system development, stress, robustness, resilience and maturity. Here we attempt to relate to the physical characteristics of the environment, ecosystem indices derived from Ecological Network Analysis. Ten models of food webs were gathered, across a selection of soft-bottom estuaries representative of a large morphological and hydrodynamic diversity, from wave-dominated to mixed energy tide-dominated systems. The selection allowed the comparison of their derived Ecological Network Analysis indices, because of similarities of accuracy in the representation of detritus and bacteria, and because models took into account all trophic levels up to top-predators. In order to obtain comparable physical characteristics, global models were used for a homogeneous description of tide and tidal prisms. Spearman correlations, hierarchical ascendant clustering and Redundancy Analysis were applied to examine the relationship between Ecological Network Analysis indices and physical characteristics. The set of four physical variables selected (catchment area, tidal range at neap tide, index of tide-wave domination and latitude in absolute value) explained 67% of the structure of the Ecological Network Analysis indices. This implies that the physical forcing related to climate, hydrodynamics and morphology is essential for determining the ecological emergent properties of the food web. In the European policy context of determining the 'good ecological status' of coastal ecosystems, it implies that the use of Ecological Network Analysis indices for basing the determination of operational indicators should be done, taking into account this context of a strong influence of physical factors.

  5. Acidity, nutrients, and minerals in atmospheric precipitation over Florida: deposition patterns, mechanisms and ecological effects

    SciTech Connect

    Brezonik, P.L.; Hendry, C.D. Jr.; Edgerton, E.S.; Schulze, R.L.; Crisman, T.L.

    1983-06-01

    A monitoring network of 21 bulk and 4 wet/dry collectors located throughout Florida measured spatial and temporal trends during a one-year period from May 1978 to April 1979. The project summary notes that statewide deposition rates of nitrogen and phosphorus were below the loading rates associated with eutrophication, although nutrient concentrations were higher during the summer. Overall, pH appears to have relatively small effects (in the range 4.7-6.8) on community structure in soft-water Florida lakes. More dramatic effects could occur under more acidic conditions in the future. 4 references, 5 figures, 1 table.

  6. December, 2004 Journal of Vector Ecology 277 Effects of interspecific competition, predation, and their interaction on

    E-print Network

    but not in an additive way. In addition, mosquito larvae in the presence of predators and competitors took two days 1992). These predators often reduce the survival of mosquito larvae (Blaustein et al. 1995, Fincke et can also be important and has been shown to have large effects on mosquito larvae. Mosquitoes compete

  7. Ecological Effects of Metals in Streams on a Defense Materials Processing Site in South Carolina, USA

    Microsoft Academic Search

    Michael H. Paller; Susan A. Dyer

    2010-01-01

    The Savannah River Site (SRS) is a 780 km U.S. Department of Energy facility near Aiken, South Carolina, established in 1950 to produce nuclear materials. SRS streams are “integrators” that potentially receive water transportable contaminants from all sources within their drainage basins, necessitating a watershed approach to organize contaminant distribution data and characterize the effects of multiple contaminants on aquatic

  8. COMPARATIVE EFFECTS OF LEAFY SPURGE ON RUMEN BACTERIAL ECOLOGY OF THE BOVINE AND OVINE.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Euphorbia esula (Leafy spurge ;LS), is a forb native to Eurasia and is considered an invasive plant species in the Northern Great Plains. Domesticated species of ruminants including goats and sheep graze leafy spurge with minimal adverse effects; however, cattle avoid areas infested with LS. When...

  9. Ecological effects of an invasive social wasp on Hawaiian arthropod communities

    E-print Network

    Wilson, Erin Elizabeth

    2009-01-01

    insect colonies may magnify top-down effects of predation aspredation and scavenging by DNA gut-content analysis: a case study using a soil insectpredation and scavenging by DNA gut-content analysis: a case study using a soil insect

  10. RESEARCH AT THE GULF ECOLOGY DIVISION ON THE EFFECTS OF LOW DISSOLVED OXYGEN ON ESTUARINE ANIMALS

    EPA Science Inventory

    Concerns about hypoxia and its effects on saltwater organisms are increasing as environmental conditions in the inshore and nearshore marine environments are better understood. Along the Gulf of Mexico coast, periods of very low dissolved oxygen (D.O.) concentrations have been re...

  11. Emergency Post-fire Rehabilitation Treatment Effects on Burned Area Ecology and Long-term Restoration

    Microsoft Academic Search

    Peter R. Robichaud; Sarah A. Lewis; Robert E. Brown; Louise E. Ashmun

    2009-01-01

    The predicted continuation of strong drying and warming trends in the southwestern Unit- ed States underlies the associated prediction of increased frequency, area, and severity of wildfires in the coming years. As a result, the management of wildfires and fire effects on public lands will continue to be a major land management priority for the foreseeable fu- ture. Following fire

  12. Salinity and Temperature Effects on Physiological Responses of Vibrio fischeri from Diverse Ecological Niches

    E-print Network

    McFall-Ngai, Margaret

    Salinity and Temperature Effects on Physiological Responses of Vibrio fischeri from Diverse isolates possessed the least variation in growth throughout the entire salinity gradient, whereas isolates. fischeri strains were also measured under a range of salinity and temperature combinations. Symbiotic V

  13. Effects of wastewater treatment plant effluent on bat foraging ecology in an urban stream system

    Microsoft Academic Search

    M. C. Kalcounis-Rueppell; V. H. Payne; S. R. Huff; A. L. Boyko

    2007-01-01

    Wastewater treatment plant (WWTP) effluent in the Cape Fear River Basin headwaters in North Carolina, USA, has influenced stream water quality and aquatic components of the stream food web. To examine effects of WWTP effluent on terrestrial predators in this system we determined prey availability, bat community structure, and bat foraging and commuting behavior at sites above and below WWTPs.

  14. CLIMATE AND LAND USE CHANGE EFFECTS ON ECOLOGICAL RESOURCES IN THREE WATERSHEDS: A SYNTHESIS REPORT

    EPA Science Inventory

    This report is a synthesis of three watershed case-study assessments conducted by GCRP to advance the capability of management decisions. The report compares and contrasts methods and processes employed by the three case study teams to learn effective analytic, project managemen...

  15. Ecological and statistical evaluation of effects of pesticides in freshwater model ecosystems

    Microsoft Academic Search

    Brink van den P. J

    1999-01-01

    Aquatic risk assessment of pesticidesThe first tier in the aquatic risk assessment procedure consists of a comparison between a Predicted Environmental Concentration (PEC) with a No Effect Concentration (NEC). A requirement for registration is that the PEC should not exceed the NEC. The NEC is calculated from the toxicity of the pesticide for defined standard test species (viz. algae Daphnia

  16. Developing tools to eradicate ecologically destructive ants on Rose Atoll: effectiveness and attractiveness of formicidal baits

    USGS Publications Warehouse

    Peck, Robert; Banko, Paul; Pendleton, Frank

    2014-01-01

    A key factor contributing to the decline in the population of Pisonia grandis on Rose Atoll is an infestation of the non-native scale, Pulvinaria urbicola (Homoptera: Coccidae). Ants, in facultative relationships with scale insects, may facilitate scale population growth and increase their effect on plant hosts. Three ant species found on Rose Atoll, Tetramorium bicarinatum, T. simillimum, and Pheidole oceanica, are capable of tending Pulvinaria on Pisonia and may have contributed to the demise of the trees on the atoll. Replicated trials conducted on Rose Atoll during 17–21 March 2013 tested the effectiveness and relative attractiveness of five formicidal baits potentially to be used to eradicate these ants on the atoll. Three baits contained toxins (hydramethylnon in Amdro® and Maxforce®, indoxacarb in Provaunt®) and two baits contained an insect growth regulator (IGR; pyriproxyfen in Distance® and s-methoprene in Tango®). Amdro, Distance, and Maxforce are granular baits while Provaunt and Tango were mixed with adjuvants to form a gel-like matrix. Results varied among ant species and baits, but Provaunt was highly effective against workers of both Tetramorium species while Amdro and Maxforce were highly effective against T. simillimum and P. oceanica. Limited time on the island prevented the evaluation of the effectiveness of the IGR baits. The relative attractiveness of the baits generally mirrored their ability to kill worker ants. Tetramorium simillimum was attracted to all five baits; T. bicarinatum was attracted to Provaunt, Distance, and Tango; and P. oceanica was attracted to the three granular baits. These results and the small area of Rose Atoll suggest that island-wide application of formicidal baits may result in eradication of these ants, but an application strategy targeting all three species would more likely succeed with the use of multiple baits.

  17. Landscape ecology

    Microsoft Academic Search

    Dean L. Urban; R. V. ONeill; Herman H. Shugart

    1987-01-01

    In this paper the authors outline an approach to landscape study that employs a hierarchical paradigm of pattern and behavior. Although emphasis is on forested landscapes, we can generalize a theory of landscape ecology. Attention is focused on the wide range of phenomena in a natural terrestrial landscape by considering the apparent complexity of landscape dynamics and illustrating how a

  18. Antimicrobial Resistance and Virulence: a Successful or Deleterious Association in the Bacterial World?

    PubMed Central

    Beceiro, Alejandro; Tomás, María

    2013-01-01

    SUMMARY Hosts and bacteria have coevolved over millions of years, during which pathogenic bacteria have modified their virulence mechanisms to adapt to host defense systems. Although the spread of pathogens has been hindered by the discovery and widespread use of antimicrobial agents, antimicrobial resistance has increased globally. The emergence of resistant bacteria has accelerated in recent years, mainly as a result of increased selective pressure. However, although antimicrobial resistance and bacterial virulence have developed on different timescales, they share some common characteristics. This review considers how bacterial virulence and fitness are affected by antibiotic resistance and also how the relationship between virulence and resistance is affected by different genetic mechanisms (e.g., coselection and compensatory mutations) and by the most prevalent global responses. The interplay between these factors and the associated biological costs depend on four main factors: the bacterial species involved, virulence and resistance mechanisms, the ecological niche, and the host. The development of new strategies involving new antimicrobials or nonantimicrobial compounds and of novel diagnostic methods that focus on high-risk clones and rapid tests to detect virulence markers may help to resolve the increasing problem of the association between virulence and resistance, which is becoming more beneficial for pathogenic bacteria. PMID:23554414

  19. Watershed Ecology and the Effects of Construction on Erosion and Water Quality

    NSDL National Science Digital Library

    Norman Leonard (Pike High School)

    2007-08-01

    The purpose of the lab is to allow middle and high school students to begin to understand their place in their watershed, explore erosion, water quality assessment and the impact of construction sites through both field work and inquiry-based experiments. Students should have prior knowledge of the water cycle. Upon completion of this activity, students will be able to describe the impact that erosion has on water quality, including the effects of soil types and potential effects of the watershed. This teaching resource was developed by a K-12 science teacher in the American Physiological SocietyÂ?s 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

  20. Residuals cannot distinguish between ecological effects of habitat amount and fragmentation: implications for the debate

    Microsoft Academic Search

    Nicola Koper; Fiona K. A. Schmiegelow; Evelyn H. Merrill

    2007-01-01

    Habitat amount and fragmentation usually covary in natural and simulated landscapes. A common way of distinguishing between\\u000a their effects is to take the residuals of the fragmentation index or indices regressed on habitat amount, as the index of\\u000a habitat fragmentation. We used data on prairie songbird relative abundances from southern Alberta, Canada to compare this\\u000a approach with the reverse: taking

  1. ECOLOGICAL EFFECTS OF METALS IN STREAMS ON A DEFENSE MATERIALS PROCESSING SITE IN SOUTH CAROLINA, USA

    Microsoft Academic Search

    M. Paller; S. Dyer

    2009-01-01

    The Savannah River Site (SRS) is a 780 km² U.S. Department of Energy facility near Aiken SC established in 1950 to produce nuclear materials. SRS streams are 'integrators' that potentially receive water transportable contaminants from all sources within their watersheds necessitating a GIS-based watershed approach to organize contaminant distribution data and accurately characterize the effects of multiple contaminant sources on

  2. The effect of petroleum operations on the phytoplankton ecology of the Louisiana coastal waters 

    E-print Network

    Fucik, K

    1974-01-01

    of oil into water (oil drilling platforms, refinery effluents, etc. ) with those in nearby areas 1'ree from these activities; and (2) a comparison of short term effects of low concentrations of oil on those biological functions which are likely... and salinity at each of two stations designated the Platform and Control stations. Water samples were also collected for the enumeration and identification of phytoplankton populations in the study area, The drilling operations have apparently had a...

  3. Ecological effects of lime treatment of acidified lakes and rivers in Sweden

    Microsoft Academic Search

    Fritz Eriksson; Einar Hörnström; Per Mossberg; Per Nyberg

    1983-01-01

    Effects on the aquatic biota of lime (CaCO3) application in acidified lakes and streams were studied in a number of waters. After treatment, lime-sensitive species of mosses (Sphagnum spp.) decreased, but species such as Potamogeton natans and Myriophyllum alterniflorum seemed to be favoured. A few years after liming species composition and diversity of phytoplankton, zooplankton and benthic insect larvae were

  4. [Effects of several ecological factors on the hatching of Sepiella maindroni wild and cultured eggs].

    PubMed

    Jiang, Xia-min; Lu, Zhu-run; He, Hai-jun; Ye, Pei-lei; Ying, Zhen; Wang, Chun-lin

    2010-05-01

    This paper compared the differences between Sepiella maindroni wild and cultured eggs, and studied the effects of temperature, salinity, hatching density, and egg type on the hatching rate and hatching time of the eggs. Wild eggs had better quality than cultured eggs. Among cultured eggs, small and black eggs had the best quality. For wild eggs, the optimum hatching temperature was 27 degrees C - 29 degrees C, and the optimum hatching salinity was 24.5-32.0. Hatching density had no significant effects on the hatching rate of wild eggs. For culturd Fol eggs, their hatching rate was 6.7% 30.0% when the temperature was 19 degrees C - 29 degrees C. No cultured eggs were hatched when the temperature was higher than 33 degrees C or lower than 17 degrees C. When the salinity was 19.5-32.0, the hatching rate of cultured eggs was 18.3%-25.0%. No hatching was observed when the salinity was below 17.0. Hatching density had no significant effects on the hatching rate of cultured eggs when air was provided, but the hatching rate was significantly affected when no air was provided. PMID:20707120

  5. Nanomaterials: biological effects and some aspects of applications in ecology and agriculture

    NASA Astrophysics Data System (ADS)

    Starodub, Nickolaj F.; Shavanova, Kateryna E.; Taran, Marina V.; Katsev, Andrey M.; Safronyuk, Sergey L.; Son'ko, Roman V.; Bisio, Chiara; Guidotti, Matteo

    2014-10-01

    Nanosized materials have shown a relevant potential for practical application in a broad number of research fields, in industrial production and in everyday life. However, these substances acquire new properties and therefore may be biologically very active. This raise questions their potential toxic effects on living organisms. In some cases the nanosized materials or nano-composites possess distinct positive properties in enhancing the adaptation of plants in unfavorable conditions and in decreasing the negative effect of some chemical substances. The information about the positive and negative effects of nano-materials as well as the data concerned to the innovative approaches used by authors for the rapid assessment of the total toxicity with the exploitation of bacteria, Daphnia and plants are given. In last case a special attention is paid to the control of natural bioluminescence and chemoluminescence of living medium of organisms, the energy of the seed germination and the efficiency of the photosynthetic apparatus in growing plants by the estimation of chlorophyll fluorescence by the special "Floratest" biosensor. Three specific clases of nano-materials are analysed: a) nano-particles ZnO, Ag2O, FeOx, TiO2 and others, b) colloidal suspension of the same compounds, and c) nanostructured layered clay materials (acid saponites and Nb-containing saponite clays). The next features are analyzed: the biocidal activity (for nanoparticles), the improvement of the nutrition of plants on calcareous soils (for colloidal structures), the activity and performances as heterogeneous catalysts (for Nb-containing saponites, as selective oxidation catalysts for toxic organosulfur compounds into non-noxious products). The chemical and physical characterization of the nanosized materials described here was studied by different spectrophotometric and microscopic techniques, including AFM and SEM.

  6. Evaluation of ecological and in vitro effects of boron on prostate cancer risk (United States)

    Microsoft Academic Search

    Wade T. Barranco; Paul F. Hudak; Curtis D. Eckhert

    2007-01-01

    Objective  To determine: (1) the correlation of prostate cancer incidence and mortality with groundwater boron and selenium concentrations;\\u000a and (2) the impact of boron on prostate cancer cell proliferation during co-treatment with alternative chemo-preventative\\u000a agents, along with boron pre-treatment effects on cell sensitivity to ionizing radiation.\\u000a \\u000a \\u000a \\u000a Methods  For regression analysis, data on prostate cancer incidence and mortality were obtained from the Texas

  7. Prediction of deleterious non-synonymous single nucleotide polymorphisms of genes related to ethanol-induced toxicity.

    PubMed

    Wang, Lin-Lin; Li, Yong; Zhou, Shu-Feng

    2009-06-01

    Non-synonymous single nucleotide polymorphisms (nsSNPs) that cause amino acid changes are believed to have a large impact on protein function. It is important to distinguish those deleterious nsSNPs that affect protein function from those that are functionally neutral. Ethanol causes organ toxicity with involvement of a number of genes encoding functional proteins. We have identified 1509 alcohol-responsive genes after a systemic search of previous human studies, with 580 being up-regulated and 847 down-regulated. The samples for gene expression analysis of ethanol exposure are from the brain, liver, and cultured human cells. These genes mainly encode proteins involved in nucleic acid binding, transcription, and signal transduction. These ethanol-responsive genes also correlated with other biological pathways, such as angiogenesis, integrin signalling pathway, and inflammation. The number of nsSNPs in the 1509 validated alcohol-responsive genes was 9207. Using the PolyPhen and SIFT algorithms, 41.5% nsSNPs were predicted to be deleterious. These findings provide some insights into the molecular targets of ethanol-induced toxicity and how genetic mutation would affect the toxicity phenotype. A better understanding of the relationship between genotype and phenotype of nsSNPs of ethanol-responsive genes will provide useful hints for further research on alcohol-induced toxicity and potential therapy. PMID:19429251

  8. Extremes in ecology: Avoiding the misleading effects of sampling variation in summary analyses

    USGS Publications Warehouse

    Link, W.A.; Sauer, J.R.

    1996-01-01

    Surveys such as the North American Breeding Bird Survey (BBS) produce large collections of parameter estimates. One's natural inclination when confronted with lists of parameter estimates is to look for the extreme values: in the BBS, these correspond to the species that appear to have the greatest changes in population size through time. Unfortunately, extreme estimates are liable to correspond to the most poorly estimated parameters. Consequently, the most extreme parameters may not match up with the most extreme parameter estimates. The ranking of parameter values on the basis of their estimates are a difficult statistical problem. We use data from the BBS and simulations to illustrate the potential misleading effects of sampling variation in rankings of parameters. We describe empirical Bayes and constrained empirical Bayes procedures which provide partial solutions to the problem of ranking in the presence of sampling variation.

  9. Physiological and ecological effects of increasing temperature on fish production in lakes of Arctic Alaska

    USGS Publications Warehouse

    Carey, Michael P.; Zimmerman, Christian E.

    2014-01-01

    Lake ecosystems in the Arctic are changing rapidly due to climate warming. Lakes are sensitive integrators of climate-induced changes and prominent features across the Arctic landscape, especially in lowland permafrost regions such as the Arctic Coastal Plain of Alaska. Despite many studies on the implications of climate warming, how fish populations will respond to lake changes is uncertain for Arctic ecosystems. Least Cisco (Coregonus sardinella) is a bellwether for Arctic lakes as an important consumer and prey resource. To explore the consequences of climate warming, we used a bioenergetics model to simulate changes in Least Cisco production under future climate scenarios for lakes on the Arctic Coastal Plain. First, we used current temperatures to fit Least Cisco consumption to observed annual growth. We then estimated growth, holding food availability, and then feeding rate constant, for future projections of temperature. Projected warmer water temperatures resulted in reduced Least Cisco production, especially for larger size classes, when food availability was held constant. While holding feeding rate constant, production of Least Cisco increased under all future scenarios with progressively more growth in warmer temperatures. Higher variability occurred with longer projections of time mirroring the expanding uncertainty in climate predictions further into the future. In addition to direct temperature effects on Least Cisco growth, we also considered changes in lake ice phenology and prey resources for Least Cisco. A shorter period of ice cover resulted in increased production, similar to warming temperatures. Altering prey quality had a larger effect on fish production in summer than winter and increased relative growth of younger rather than older age classes of Least Cisco. Overall, we predicted increased production of Least Cisco due to climate warming in lakes of Arctic Alaska. Understanding the implications of increased production of Least Cisco to the entire food web will be necessary to predict ecosystem responses in lakes of the Arctic.

  10. Physiological and ecological effects of increasing temperature on fish production in lakes of Arctic Alaska.

    PubMed

    Carey, Michael P; Zimmerman, Christian E

    2014-05-01

    Lake ecosystems in the Arctic are changing rapidly due to climate warming. Lakes are sensitive integrators of climate-induced changes and prominent features across the Arctic landscape, especially in lowland permafrost regions such as the Arctic Coastal Plain of Alaska. Despite many studies on the implications of climate warming, how fish populations will respond to lake changes is uncertain for Arctic ecosystems. Least Cisco (Coregonus sardinella) is a bellwether for Arctic lakes as an important consumer and prey resource. To explore the consequences of climate warming, we used a bioenergetics model to simulate changes in Least Cisco production under future climate scenarios for lakes on the Arctic Coastal Plain. First, we used current temperatures to fit Least Cisco consumption to observed annual growth. We then estimated growth, holding food availability, and then feeding rate constant, for future projections of temperature. Projected warmer water temperatures resulted in reduced Least Cisco production, especially for larger size classes, when food availability was held constant. While holding feeding rate constant, production of Least Cisco increased under all future scenarios with progressively more growth in warmer temperatures. Higher variability occurred with longer projections of time mirroring the expanding uncertainty in climate predictions further into the future. In addition to direct temperature effects on Least Cisco growth, we also considered changes in lake ice phenology and prey resources for Least Cisco. A shorter period of ice cover resulted in increased production, similar to warming temperatures. Altering prey quality had a larger effect on fish production in summer than winter and increased relative growth of younger rather than older age classes of Least Cisco. Overall, we predicted increased production of Least Cisco due to climate warming in lakes of Arctic Alaska. Understanding the implications of increased production of Least Cisco to the entire food web will be necessary to predict ecosystem responses in lakes of the Arctic. PMID:24963391

  11. Physiological and ecological effects of increasing temperature on fish production in lakes of Arctic Alaska

    PubMed Central

    Carey, Michael P; Zimmerman, Christian E

    2014-01-01

    Lake ecosystems in the Arctic are changing rapidly due to climate warming. Lakes are sensitive integrators of climate-induced changes and prominent features across the Arctic landscape, especially in lowland permafrost regions such as the Arctic Coastal Plain of Alaska. Despite many studies on the implications of climate warming, how fish populations will respond to lake changes is uncertain for Arctic ecosystems. Least Cisco (Coregonus sardinella) is a bellwether for Arctic lakes as an important consumer and prey resource. To explore the consequences of climate warming, we used a bioenergetics model to simulate changes in Least Cisco production under future climate scenarios for lakes on the Arctic Coastal Plain. First, we used current temperatures to fit Least Cisco consumption to observed annual growth. We then estimated growth, holding food availability, and then feeding rate constant, for future projections of temperature. Projected warmer water temperatures resulted in reduced Least Cisco production, especially for larger size classes, when food availability was held constant. While holding feeding rate constant, production of Least Cisco increased under all future scenarios with progressively more growth in warmer temperatures. Higher variability occurred with longer projections of time mirroring the expanding uncertainty in climate predictions further into the future. In addition to direct temperature effects on Least Cisco growth, we also considered changes in lake ice phenology and prey resources for Least Cisco. A shorter period of ice cover resulted in increased production, similar to warming temperatures. Altering prey quality had a larger effect on fish production in summer than winter and increased relative growth of younger rather than older age classes of Least Cisco. Overall, we predicted increased production of Least Cisco due to climate warming in lakes of Arctic Alaska. Understanding the implications of increased production of Least Cisco to the entire food web will be necessary to predict ecosystem responses in lakes of the Arctic. PMID:24963391

  12. Evaluation of terrestrial microcosms for assessing the fate and effects of genetically engineered microorganisms on ecological processes

    SciTech Connect

    Fredrickson, J.K.; Bentjen, S.A.; Bolton, H. Jr.; Li, S.W.; Ligotke, M.W.; McFadden, K.M.; Van Voris, P.

    1989-04-01

    This project evaluates and modifies the existing US Environmental Protection Agency's Office of Pesticides and Toxic Substances (EPA/OPTS) terrestrial microcosm test system and test protocols such that they can be used to determine the environmental fate and ecological hazards of genetically engineered microorganisms (GEMs). The intact soil-core microcosm represents terrestrial ecosystems, and when coupled with appropriate test protocols, such microcosms may be appropriate to define and limit risks associated with the intentional release of GEMs. The terrestrial microcosm test system was used to investigate the survival and transport of two model GEMs (Azospirillum lipoferum and Pseudomonas sp. Tn5 mutants) to various trophic levels and niches and through intact soil cores. Subsequent effects on nutrient cycling and displacement of indigenous microorganisms were evaluated. The model organisms were a diazotrophic root-colonizing bacterium (A. lipoferum) and a wheat root growth-inhibiting rhizobacterium (Pseudomonas sp.). The transposable element Tn5 was used as a genetic marker for both microorganisms in two separate experiments. The organisms were subjected to transposon mutagenesis using a broad host-range-mobilizable suicide plasmid. The transposon Tn5 conferred levels of kanamycin resistance up to 500 ..mu..g/ml (Pseudomonas sp.), which allowed for selection of the bacteria from environmental samples. The presence of Tn5 DNA in the genome of the model GEMs also allowed the use of Tn5 gene probes to confirm and enumerate the microorganisms in different samples from the microcosms. Two types of root growth-inhibiting Pseudomonas sp. Tn5 mutants were obtained and used in microcosm studies: those that lacked the ability to inhibit either wheat root growth or the growth of other microorganisms in vitro (tox/sup /minus//) and those which retained these properties (tox/sup +/). 53 refs., 7 figs., 6 tabs.

  13. Effects of food supplementation on the physiological ecology of female Western diamond-backed rattlesnakes (Crotalus atrox).

    PubMed

    Taylor, Emily N; Malawy, Michael A; Browning, Dawn M; Lemar, Shea V; DeNardo, Dale F

    2005-06-01

    Food availability is an important factor in the life histories of organisms because it is often limiting and thus can affect growth, mass change, reproduction, and behaviors such as thermoregulation, locomotion, and mating. Experimental studies in natural settings allow researchers to examine the effects of food on these parameters while animals are free to behave naturally. The wide variation among organisms in energy demands and among environmental food resources suggest that responses to changes in food availability may vary among organisms. Since most supplemental feeding field experiments have been conducted on species with high energy demands, we conducted a supplemental feeding study on free-ranging, female Western diamond-backed rattlesnakes (Crotalus atrox), a species with low energy demands and infrequent reproductive investment. Snakes were offered thawed rodents 1-4 times per week. Over two active seasons, we collected data on surface activity, home range size, growth, mass change, and reproduction of supplementally fed and control snakes. Fed and control snakes did not differ in surface activity levels (proportion of time encountered above versus below ground) or home range size. Fed snakes grew and gained mass faster, and had a dramatically higher occurrence of reproduction than control snakes. Also, fed snakes were in better body condition following reproduction than snakes that were not fed. However, litter characteristics such as offspring number and size were not increased by feeding, suggesting that these characteristics may be fixed. These data experimentally demonstrate that food availability can directly impact some life history traits (i.e., growth and reproduction for C. atrox), but not others (i.e., surface activity and home range size for C. atrox). The relationship between food availability and life history traits is affected in a complex way by ecological traits and physiological constraints, and thus interspecific variation in this relationship is likely to be high. PMID:15800735

  14. Type A behavior: an ecological approach.

    PubMed

    Margolis, L H; McLeroy, K R; Runyan, C W; Kaplan, B H

    1983-09-01

    The recognized association between Type A behavior and coronary heart disease has prompted efforts to alter the behavior's deleterious components in both individuals who have experienced myocardial infarction and those who are at risk for that disease. Utilizing concepts from psychology, sociology, history, and other disciplines and material from scholarly and popular literature, this paper suggests that instead of singularly concentrating on components at the level of the individual, it is important to view Type A behavior from an ecological perspective, with attention directed at the interpersonal, institutional, and cultural environments of individuals. This perspective will enhance understanding of Type A behavior and possibly stimulate interventions at the primary as well as secondary and tertiary prevention levels. PMID:6663613

  15. An ecological risk assessment of the acute and chronic effects of the herbicide clopyralid to rainbow trout (Oncorhynchus mykiss).

    PubMed

    Fairchild, J F; Allert, A L; Feltz, K P; Nelson, K J; Valle, J A

    2009-11-01

    Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide frequently used to control invasive, noxious weeds in the northwestern United States. Clopyralid exhibits low acute toxicity to fish, including the rainbow trout (Oncorhynchus mykiss) and the threatened bull trout (Salvelinus confluentus). However, there are no published chronic toxicity data for clopyralid and fish that can be used in ecological risk assessments. We conducted 30-day chronic toxicity studies with juvenile rainbow trout exposed to the acid form of clopyralid. The 30-day maximum acceptable toxicant concentration (MATC) for growth, calculated as the geometric mean of the no observable effect concentration (68 mg/L) and the lowest observable effect concentration (136 mg/L), was 96 mg/L. No mortality was measured at the highest chronic concentration tested (273 mg/L). The acute:chronic ratio, calculated by dividing the previously published 96-h acutely lethal concentration (96-h ALC(50); 700 mg/L) by the MATC was 7.3. Toxicity values were compared to a four-tiered exposure assessment profile assuming an application rate of 1.12 kg/ha. The Tier 1 exposure estimation, based on direct overspray of a 2-m deep pond, was 0.055 mg/L. The Tier 2 maximum exposure estimate, based on the Generic Exposure Estimate Concentration model (GEENEC), was 0.057 mg/L. The Tier 3 maximum exposure estimate, based on previously published results of the Groundwater Loading Effects of Agricultural Management Systems model (GLEAMS), was 0.073 mg/L. The Tier 4 exposure estimate, based on published edge-of-field monitoring data, was estimated at 0.008 mg/L. Comparison of toxicity data to estimated environmental concentrations of clopyralid indicates that the safety factor for rainbow trout exposed to clopyralid at labeled use rates exceeds 1000. Therefore, the herbicide presents little to no risk to rainbow trout or other salmonids such as the threatened bull trout. PMID:19777152

  16. An ecological risk assessment of the exposure and effects of 2,4-D acid to rainbow trout (Onchorhyncus mykiss).

    PubMed

    Fairchild, J F; Feltz, K P; Allert, A L; Sappington, L C; Nelson, K J; Valle, J A

    2009-05-01

    Numerous state and federal agencies are increasingly concerned with the rapid expansion of invasive, noxious weeds across the United States. Herbicides are frequently applied as weed control measures in forest and rangeland ecosystems that frequently overlap with critical habitats of threatened and endangered fish species. However, there is little published chronic toxicity data for herbicides and fish that can be used to assess ecological risk of herbicides in aquatic environments. We conducted 96-h flowthrough acute and 30-day chronic toxicity studies with swim-up larvae and juvenile rainbow trout (Onchorhyncus mykiss) exposed to the free acid form of 2,4-D. Juvenile rainbow trout were acutely sensitive to 2,4-D acid equivalent at 494 mg/L (95% confidence interval [CI] 334-668 mg/L; 96-h ALC(50)). Accelerated life-testing procedures, used to estimate chronic mortality from acute data, predicted that a 30-day exposure of juvenile rainbow trout to 2,4-D would result in 1% and 10% mortality at 260 and 343 mg/L, respectively. Swim-up larvae were chronically more sensitive than juveniles using growth as the measurement end point. The 30-day lowest observable effect concentration (LOEC) of 2,4-D on growth of swim-up larvae was 108 mg/L, whereas the 30-day no observable effect concentration (NOEC) was 54 mg/L. The 30-day maximum acceptable toxicant concentration (MATC) of 2,4-D for rainbow trout, determined as the geometric mean of the NOEC and the LOEC, was 76 mg/L. The acute:chronic ratio was 6.5 (i.e., 494/76). We observed no chronic effects on growth of juvenile rainbow trout at the highest concentration tested (108 mg/L). Worst-case aquatic exposures to 2,4-D (4 mg/L) occur when the herbicide is directly applied to aquatic ecosystems for aquatic weed control and resulted in a 30-day safety factor of 19 based on the MATC for growth (i.e., 76/4). Highest nontarget aquatic exposures to 2,4-D applied following terrestrial use is calculated at 0.136 mg/L and resulted in a 30-day safety factor of 559 (e.g., 76/0.163). Assessment of the exposure and response data presented herein indicates that use of 2,4-D acid for invasive weed control in aquatic and terrestrial habitats poses no substantial risk to growth or survival of rainbow trout or other salmonids, including the threatened bull trout (Salvelinus confluentus). PMID:19165410

  17. An ecological risk assessment of the exposure and effects of 2,4-D acid to rainbow trout (Onchorhyncus mykiss)

    USGS Publications Warehouse

    Fairchild, J.F.; Feltz, K.P.; Allert, A.L.; Sappington, L.C.; Nelson, K.J.; Valle, J.A.

    2009-01-01

    Numerous state and federal agencies are increasingly concerned with the rapid expansion of invasive, noxious weeds across the United States. Herbicides are frequently applied as weed control measures in forest and rangeland ecosystems that frequently overlap with critical habitats of threatened and endangered fish species. However, there is little published chronic toxicity data for herbicides and fish that can be used to assess ecological risk of herbicides in aquatic environments. We conducted 96-h flowthrough acute and 30-day chronic toxicity studies with swim-up larvae and juvenile rainbow trout (Onchorhyncus mykiss) exposed to the free acid form of 2,4-D. Juvenile rainbow trout were acutely sensitive to 2,4-D acid equivalent at 494 mg/L (95% confidence interval [CI] 334-668 mg/L; 96-h ALC50). Accelerated life-testing procedures, used to estimate chronic mortality from acute data, predicted that a 30-day exposure of juvenile rainbow trout to 2,4-D would result in 1% and 10% mortality at 260 and 343 mg/L, respectively. Swim-up larvae were chronically more sensitive than juveniles using growth as the measurement end point. The 30-day lowest observable effect concentration (LOEC) of 2,4-D on growth of swim-up larvae was 108 mg/L, whereas the 30-day no observable effect concentration (NOEC) was 54 mg/L. The 30-day maximum acceptable toxicant concentration (MATC) of 2,4-D for rainbow trout, determined as the geometric mean of the NOEC and the LOEC, was 76 mg/L. The acute:chronic ratio was 6.5 (i.e., 494/76). We observed no chronic effects on growth of juvenile rainbow trout at the highest concentration tested (108 mg/L). Worst-case aquatic exposures to 2,4-D (4 mg/L) occur when the herbicide is directly applied to aquatic ecosystems for aquatic weed control and resulted in a 30-day safety factor of 19 based on the MATC for growth (i.e., 76/4). Highest nontarget aquatic exposures to 2,4-D applied following terrestrial use is calculated at 0.136 mg/L and resulted in a 30-day safety factor of 559 (e.g., 76/0.163). Assessment of the exposure and response data presented herein indicates that use of 2,4-D acid for invasive weed control in aquatic and terrestrial habitats poses no substantial risk to growth or survival of rainbow trout or other salmonids, including the threatened bull trout (Salvelinus confluentus). ?? 2009 US Government.

  18. Is ecosystem structure the target of concern in ecological effect assessments?

    PubMed

    De Laender, Frederik; De Schamphelaere, Karel A C; Vanrolleghem, Peter A; Janssen, Colin R

    2008-05-01

    The species sensitivity distribution, a technique currently used to derive water-quality standards of chemicals, is associated with a set of inadequately tested assumptions. One of these assumptions is that ecosystem structure is as or more sensitive than ecosystem function, i.e., that structure is the target of concern. In this paper, we tested this assumption for a simple freshwater ecosystem exposed to different toxicants. Using an ecosystem model, we calculated no observed effect concentrations (NOECs) for ecosystem structure (ecosystem structure-NOECs) and function (ecosystem function-NOECs) for each of 1000 hypothetical toxicants. For 979 of these toxicants, the ecosystem structure-NOEC was lower than or equal to the ecosystem function-NOEC, indicating that the tested assumption can be considered valid. For 239 of these 979 toxicants, both NOECs were equal. For half of the 1000 toxicants, the structure of lower trophic levels (i.e., phytoplankton) appears to be more sensitive than the structure of higher trophic levels (i.e., fish). As such, ecosystem structure-NOECs are primarily determined by the sensitivity of the structure of lower trophic levels. In contrast, ecosystem functions associated with higher trophic levels (e.g., total ingestion by fish) are more sensitive than functions associated with lower trophic levels (e.g., total photosynthesis by phytoplankton) for 749 toxicants. PMID:18258280

  19. Ecological Effects of Roads on the Plant Diversity of Coastal Wetland in the Yellow River Delta

    PubMed Central

    Li, Yunzhao; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

    2014-01-01

    The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of ?T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0–20?m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing ?-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20?m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion. PMID:25147872

  20. Ecological effects of pipeline construction through deciduous forested wetlands, Midland County, Michigan

    SciTech Connect

    Zellmer, S.D. (Argonne National Lab., IL (United States)); Rastorfer, J.R. (Chicago State Univ., IL (United States). Dept. of Biological Sciences ANL/CSU Cooperative Herbarium, Chicago, IL (United States)); Van Dyke, G.D. (Trinity Christian Coll., Palos Heights, IL (United States). Dept. of Biology)

    1991-07-01

    Implementation of recent federal and state regulations promulgated to protect wetlands makes information on effects of gas pipeline rights-of-way (ROWs) in wetlands essential to the gas pipeline industry. This study is designed to record vegetational changes induced by the construction of a large-diameter gas pipeline through deciduous forested wetlands. Two second-growth forested wetland sites mapped as Lenawee soils, one mature and one subjected to recent selective logging, were selected in Midland County, Michigan. Changes in the adjacent forest and successional development on the ROW are being documented. Cover-class estimates are being made for understory and ROW plant species using 1 {times}1-m quadrats. Counts are also being made for all woody species with stems < 2 cm in diameter at breast height (dbh) in the same plots used for cover-class estimates. Individual stem diameters and species counts are being recorded for all woody understory and overstory plants with stems {ge}2 cm dbh in 10 {times} 10-m plots. Although analyses of the data have not been completed, preliminary analyses indicate that some destruction of vegetation at the ROW forest edge may have been avoidable during pipeline construction. Rapid regrowth of many native wetland plant species on the ROW occurred because remnants of native vegetation and soil-bearing propagules of existing species survived on the ROW after pipeline construction and seeding operations. 91 refs., 11 figs., 3 tabs.

  1. Effects of waterlogging on seed germination of three Mediterranean oak species: Ecological implications

    NASA Astrophysics Data System (ADS)

    Pérez-Ramos, Ignacio M.; Marañón, Teodoro

    2009-05-01

    Soil water saturation during prolonged periods of time generates a negative impact on nearly all terrestrial plants. In Mediterranean woodlands, precipitation can be very abundant during the wet season, inducing temporary soil waterlogging, coinciding with the seed dispersal and germination time of many species. We investigated the effects of waterlogging on seed germination and early root growth of three coexisting oak species ( Quercus canariensis, Q. suber and Q. pyrenaica), by completely flooding of seeds for various periods of time. The three oak species showed a certain level of tolerance to waterlogging, only being affected those seeds subjected for long periods of submersion (over 30 days). Waterlogging during prolonged periods of time decreased the probability of seed germination in the three oak species, lengthened the time to germination, and hampered root development in two of the studied species. The main differences between oak species occurred in terms of root growth ( Q. canariensis being the less affected, and Q. suber the most); these differential responses could be related to a species rank of waterlogging tolerance. Thus inter-specific differences in germination responses to waterlogging could contribute to explain, at least partially, species habitat and distribution patterns across landscapes. Seed mass also played an important role on different aspects of germination, though its relative importance varied as function of species and waterlogging treatment. The tolerance to stress induced by waterlogging increased with seed mass, but only in the case of Q. canariensis.

  2. Ecological effects of roads on the plant diversity of coastal wetland in the Yellow River Delta.

    PubMed

    Li, Yunzhao; Yu, Junbao; Ning, Kai; Du, Siyao; Han, Guangxuan; Qu, Fanzhu; Wang, Guangmei; Fu, Yuqin; Zhan, Chao

    2014-01-01

    The 26 sample sites in 7 study plots adjacent to asphalt road and earth road in coastal wetland in the Yellow River Delta were selected to quantify plant diversity using quadrat sampling method in plant bloom phase of July and August 2012. The indice of ? T and Jaccard's coefficient were applied to evaluate the species diversity. The results showed that the plant diversities and alien plants were high in the range of 0-20 m to the road verge. There were more exotics and halophytes in plots of asphalt roadside than that of earth roadside. However, proportion of halophytes in habitats of asphalt roadsides was lower than that of earth roadside. By comparing ?-diversity, there were more common species in the asphalt roadsides than that in the earth roadsides. The similarity of plant communities in studied plots of asphalt roadsides and earth roadsides increased with increasing the distance to road verge. The effect range of roads for plant diversity in study region was about 20 m to road verge. Our results indicate that the construction and maintenance of roads in wetland could increase the plant species diversities of communities and risk of alien species invasion. PMID:25147872

  3. Effect of Lineage-Specific Metabolic Traits of Lactobacillus reuteri on Sourdough Microbial Ecology

    PubMed Central

    Lin, Xiaoxi B.

    2014-01-01

    This study determined the effects of specific metabolic traits of Lactobacillus reuteri on its competitiveness in sourdoughs. The competitiveness of lactobacilli in sourdough generally depends on their growth rate; acid resistance additionally contributes to competitiveness in sourdoughs with long fermentation times. Glycerol metabolism via glycerol dehydratase (gupCDE) accelerates growth by the regeneration of reduced cofactors; glutamate metabolism via glutamate decarboxylase (gadB) increases acid resistance by generating a proton motive force. Glycerol and glutamate metabolisms are lineage-specific traits in L. reuteri; therefore, this study employed glycerol dehydratase-positive sourdough isolates of human-adapted L. reuteri lineage I, glutamate decarboxylase-positive strains of rodent-adapted L. reuteri lineage II, as well as mutants with deletions in gadB or gupCDE. The competitivenesses of the strains were quantified by inoculation of wheat and sorghum sourdoughs with defined strains, followed by propagation of doughs with a 10% inoculum and 12-h or 72-h fermentation cycles. Lineage I L. reuteri strains dominated sourdoughs propagated with 12-h fermentation cycles; lineage II L. reuteri strains dominated sourdoughs propagated with 72-h fermentation cycles. L. reuteri 100-23?gadB was outcompeted by its wild-type strain in sourdoughs fermented with 72-h fermentation cycles; L. reuteri FUA3400?gupCDE was outcompeted by its wild-type strain in sourdoughs fermented with both 12-h and 72-h fermentation cycles. Competition experiments with isogenic pairs of strains resulted in a constant rate of strain displacement of the less competitive mutant strain. In conclusion, lineage-specific traits of L. reuteri determine the competitiveness of this species in sourdough fermentations. PMID:25015888

  4. Effects of spatial subsidies and habitat structure on the foraging ecology and size of geckos

    USGS Publications Warehouse

    Briggs, Amy A.; Young, Hillary S.; McCauley, Douglas J.; Hathaway, Stacie A.; Dirzo, Rodolfo; Fisher, Robert N.

    2012-01-01

    While it is well established that ecosystem subsidies—the addition of energy, nutrients, or materials across ecosystem boundaries—can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species (Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ trongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length.

  5. Energy effectiveness and the ecology of work: Links to productivity and well-being

    SciTech Connect

    Heerwagen, J.; Johnson, J.A.; Brothers, P.; Little, R.; Rosenfeld, A.

    1998-07-01

    In general, research on the positive outcomes of buildings lags behind research on problems and discomforts. A similar state exists in the field of medicine. The medical profession knows far more about what makes us sick than what makes us healthy. However, they also know that the mere absence of bad habits does not by itself promotes good health. Healthiness derives from a very different set of characteristics--including one's social network, psychological hardiness, general outlook on life, and a perceived sense of control over life situations. Research and theory in environmental psychology suggests that a similar situation exists in buildings. That is, the mere absence of discomforts and problems may not by itself produce high states of well being and performance. Realization of well-being and performance benefits may depend upon the degrees to which a building directly or indirectly affects psychological and cognitive functioning and physical health. An accumulating body of research in cognitive neuroscience, health psychology, and organizational behavior suggests that the physical environment can play a role in cultivating high states of well being and performance. While some of these features and attributes are directly related to energy efficient design, others have more indirect, and less obvious, linkages. In this paper, the authors look at research on factors affecting human performance, with an emphasis on information and knowledge based work. The paper includes a discussion about the effects of building design features on performance, well being, and comfort. They explore the energy linkages, both direct and indirect, in the final section of the paper.

  6. Effects of Spatial Subsidies and Habitat Structure on the Foraging Ecology and Size of Geckos

    PubMed Central

    McCauley, Douglas J.; Hathaway, Stacie A.; Dirzo, Rodolfo; Fisher, Robert N.

    2012-01-01

    While it is well established that ecosystem subsidies—the addition of energy, nutrients, or materials across ecosystem boundaries—can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species (Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ strongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length. PMID:22899995

  7. Copycat effects after media reports on suicide: a population-based ecologic study.

    PubMed

    Niederkrotenthaler, Thomas; Till, Benedikt; Kapusta, Nestor D; Voracek, Martin; Dervic, Kanita; Sonneck, Gernot

    2009-10-01

    This study aimed to investigate whether the risk of increased suicide occurrence after reports on suicide is associated with the social characteristics of the reported suicides and whether this varies with similarity between the reported suicides and suicides in the population. We collected reports on all 179 individual suicides named in the 13 largest Austrian nationwide newspapers from 1996 to 2006. Information on social status and sociodemographic characteristics of the reported suicides, on certainty of labelling the death as a suicide, and on the suicide methods applied were extracted from the articles. We conducted logistic regression analyses, with the increase of post-report suicides within 28 days after the reports as dependent variable. In model 1, the increase of suicides that matched the reported individual suicide with regard to age group, sex and suicide method was used as outcome variable. In model 2, the increase of suicides that were different from the reported suicide with regard to these characteristics was the outcome. In model 3, the post-report increase of total suicides was the dependent variable. Celebrity status of the reported suicide, age of the reported suicide between 30 and 64 years, and definitive labelling as a suicide were associated with an increased risk of a post-report increase of similar suicides; criminality (i.e. the individual was reported as suspected or convicted of crime) of the reported suicide was associated with a lower risk of a post-report increase. In dissimilar suicides, none of the variables was associated with a post-report increase of suicides. Celebrity status of the reported suicide was the only predictor of a post-report increase of total suicides. The findings support the hypothesis that social variables of reported suicides impact the risk of post-report copycat behaviour. Evidence of copycat effects seemed to be strongest in suicides that were similar to the respective model with regard to age group, sex, and suicide method. PMID:19682782

  8. Ecological study of effect of breast feeding on infant mortality in Latin America

    PubMed Central

    Betrán, Ana P; de Onís, Mercedes; Lauer, Jeremy A; Villar, José

    2001-01-01

    Objective To estimate the effect of exclusive breast feeding and partial breast feeding on infant mortality from diarrhoeal disease and acute respiratory infections in Latin America. Design Attributable fraction analysis of national data on infant mortality and breast feeding. Setting Latin America and the Caribbean. Main outcome measures Mortality from diarrhoeal disease and acute respiratory infections and nationally representative breastfeeding rates. Results 55% of infant deaths from diarrhoeal disease and acute respiratory infections in Latin America are preventable by exclusive breast feeding among infants aged 0-3 months and partial breast feeding throughout the remainder of infancy. Among infants aged 0-3 months, 66% of deaths from these causes are preventable by exclusive breast feeding; among infants aged 4-11 months, 32% of such deaths are preventable by partial breast feeding. 13.9% of infant deaths from all causes are preventable by these breastfeeding patterns. The annual number of preventable deaths is about 52?000 for the region. Conclusions Exclusive breast feeding of infants aged 0-3 months and partial breast feeding throughout the remainder of infancy could substantially reduce infant mortality in Latin America. Interventions to promote breast feeding should target younger infants. What is already known on this topicInfant mortality is lower among breast fed than non-breast fed infantsThe reductions are greatest for deaths from diarrhoeal disease and acute respiratory infectionsWhat this study addsExclusive breast feeding of infants aged 0-3 months and partial breast feeding for the remainder of the first year would prevent about 52?000 infant deaths a year in Latin AmericaThis corresponds to 13.9% of infant deaths from all causesPromotion of breast feeding has an important role in increasing survival of infants PMID:11498485

  9. Ecology 2005 93, 853862

    E-print Network

    Bermingham, Eldredge

    role for species-specific processes. Key-words: community ecology, dispersal assembly, Panama, seed addition experiment, seed limitation, seed size, seedling ecology, seedling recruitment, tropical ecologyJournal of Ecology 2005 93, 853­862 © 2005 British Ecological Society Blackwell Publishing, Ltd

  10. Tectonic ecology.

    PubMed

    Muir Wood, R

    1987-09-01

    Earthquakes and volcanic eruptions affect ecosystems on a variety of scales. Trees are particularly susceptible to land movements associated with major fault activity and dendrological studies offer ways of dating past earthquakes, thereby assisting in the prediction of future events. Major eruptions and the largest earthquakes can cause damage that affects patterns of ecological diversity across wide areas, offering a possible measure of earthquake frequency from community composition. PMID:21227867

  11. The effects of climate change on fungal diversity patterns in the UK and Greece: Contrasting trends and ecological interpretations

    NASA Astrophysics Data System (ADS)

    Damialis, A.; Gange, A. C.; Mohammad, A. B.; Halley, J. M.

    2013-05-01

    It is well known that climate change has been affecting the ecology of living organisms. However, very little research has been done concerning alterations in fungal ecology. The changes in climate are expected to have an impact on fungal biodiversity patterns. Such changes in turn might have implications for public health since the spores of certain fungal taxa (e.g. Alternaria, Cladosporium) cause respiratory problems in sensitised individuals, with symptoms manifested even as acute respiratory failure. The objectives of this study were: a) to perform a comprehensive analysis of trends in long-term time series of fungal fruiting and sporulation variables for a wide range of fungal taxa, b) to investigate the response of fungal abundance and diversity to environmental variability. Data from two different geoclimatic areas were used: a) England, UK from more than 350 fungal species belonging to 10 different functional groups and with phenological records of fungal fruiting (start, end and duration) since 1950, b) Thessaloniki, Greece for 14 airborne fungal types with quantitative records (total annual concentration) and phenological records (start, peak, end, duration) of the atmospheric spore season since 1987. In parallel, various meteorological factors were examined in both areas in order to elucidate the relationship between climate and fungal diversity patterns. Long-term trends were found in most cases: these were particularly pronounced in the UK, where more than 300 species (~82%) displayed trends. Of these, ~77% were towards an earlier beginning and ~81% towards a later ending of the fruiting season; overall, an extension of the fruiting season seems to occur in more than 200 species. On a per-functional-group basis, except for manure, soil and mycorrhizal deciduous fungal species, all the other (137 species) exhibited earlier first fruiting dates and extended seasons. On the other hand, in Greece, although a tendency was observed towards lower yearly spore concentration (86% of the total) and later and shorter spore season (86% and 71% of the total, respectively), most cases only approached statistical significance. However, in both study areas the sole meteorological factor to change significantly over the last decades was minimum air temperature, and especially in the case of Thessaloniki, Greece. We observed a persistent correlation of this factor with fungal data, which frequently revealed a lag-effect of several decades. Particularly in the longer time-series of fungal fruiting in the UK, several fungal functional groups and species displayed a persistent 'memory' lasting up to four decades in the past as observed through patterns of variance growth. Biodiversity in the two study areas exhibits contrasting patterns over time with diversity increasing with time in the UK and decreasing in Greece, which suggests a more nuanced role for climate change as a driver of fungal diversity.

  12. Fermented and nonfermented liquid feed to growing pigs: effect on aspects of gastrointestinal ecology and growth performance.

    PubMed

    Canibe, N; Jensen, B B

    2003-08-01

    The effect of feeding dry feed (DF), nonfermented liquid feed (NFLF), and fermented liquid feed (FLF) to growing pigs on aspects of gastrointestinal ecology and on performance was investigated. Nonfermented liquid feed was prepared by mixing feed and water at a ratio of 1:2.5 immediately before feeding. Fermented liquid feed was prepared by mixing feed and water in the same ratio as NFLF, and stored in a tank at 20 degrees C for 4 d, after which half the volume was removed twice daily at each feeding and replaced with the same volume of feed and water mixture. A total of 60 pigs (initial BW of 30.7 kg) from 20 litters was used. Twenty pigs, housed individually, were allotted to each of the diets and fed restrictively. Five pigs from each diet were sacrificed at an average BW of 112 kg and digesta from the gastrointestinal tract (GI-tract) was obtained to examine variables describing some aspects of the gastrointestinal ecology. Fermented liquid feed contained high levels of lactic acid bacteria (9.4 log cfu/g) and lactic acid (approximately 169 mmol/kg), low levels of enterobacteria (<3.2 log cfu/g), and had a low pH (4.4). Nonfermented liquid feed contained 7.2 log cfu/g of lactic acid bacteria, and 6.2 log cfu/g of enterobacteria, which indicated that fermentation had started in the feed. The pigs fed FLF had the lowest levels of enterobacteria along the GI-tract (<3.2 to 5.0 log cfu/g), and those fed NFLF the highest levels (5.7 to 6.6 log cfu/g; P < or = 0.02). Fermented liquid feed caused a decrease in gastric pH from 4.4 and 4.6 for DF and NLF, to 4.0 (P = 0.003), and increased numerically the gastric concentration of lactic acid (P = 0.17) from 50 to 60 mmol/kg in the DF and NFLF treatments to 113 mmol/kg in the FLF treatment. The animals fed NFLF showed the highest weight gain (995 g/d) and feed intake (2.14 kg/d), and those fed FLF the lowest values (weight gain, 931 g/d; feed intake, 1.96 kg/d; P = 0.003 for weight gain, and P < 0.001 for feed intake). The results from the present study indicate that feeding FLF as prepared here may be a valid feeding strategy to decrease the levels of enterobacteria in the GI-tract of growing pigs, whereas feeding liquid feed that has started to ferment (high levels of enterobacteria and high pH as with NFLF) increases the presence of these undesirable bacteria. Nonetheless, higher daily feed intake and body weight gain are obtained when feeding NFLF compared with feeding FLF or DF. PMID:12926784

  13. Effects of fire on the nutritional ecology of selected ungulates in the southern Black Hills, South Dakota

    E-print Network

    Dakota By Teresa J. Zimmerman A thesis submitted in partial fulfillment of the requirements family, Wayne and Jeanette Zimmerman, Ronny, Cindi, Ashley, and Clay Jackson, and Sheri Zimmerman. Words ON THE NUTRITIONAL ECOLOGY OF SELECTED UNGULATES IN THE SOUTHERN BLACK HILLS, SOUTH DAKOTA Teresa J. Zimmerman 2004

  14. Department of Ecology & Evolutionary

    E-print Network

    Wilmers, Chris

    physiology Ingrid M. Parker * Plant ecology, plant-pathogen interactions, biological invasions Eric Palkovacs-animal interactions Kathleen Kay * Plant evolutionary ecology A. Marm Kilpatrick * Disease ecology, population biology

  15. Ecology 2005 93, 431440

    E-print Network

    , phenotypic plasticity, population age, reproductive value, senescence, succession Journal of Ecology (2005. Plastic changes in seed dispersal along ecological succession: theoretical predictions from and evolutionary relevance of plastic changes in seed dispersal along ecological succession. Our model describes

  16. NORMATIVE SCIENCE: A CORRUPTING INFLUENCE IN ECOLOGICAL POLICY

    EPA Science Inventory

    Effectively resolving the typical ecological policy issue requires providing an array of scientific information to decision-makers. In my experience, the ability of scientists (and scientific information) to constructively inform ecological policy deliberations has been diminish...

  17. Exome sequencing of senescence-accelerated mice (SAM) reveals deleterious mutations in degenerative disease-causing genes

    PubMed Central

    2013-01-01

    Background Senescence-accelerated mice (SAM) are a series of mouse strains originally derived from unexpected crosses between AKR/J and unknown mice, from which phenotypically distinct senescence-prone (SAMP) and -resistant (SAMR) inbred strains were subsequently established. Although SAMP strains have been widely used for aging research focusing on their short life spans and various age-related phenotypes, such as immune dysfunction, osteoporosis, and brain atrophy, the responsible gene mutations have not yet been fully elucidated. Results To identify mutations specific to SAMP strains, we performed whole exome sequencing of 6 SAMP and 3 SAMR strains. This analysis revealed 32,019 to 38,925 single-nucleotide variants in the coding region of each SAM strain. We detected Ogg1 p.R304W and Mbd4 p.D129N deleterious mutations in all 6 of the SAMP strains but not in the SAMR or AKR/J strains. Moreover, we extracted 31 SAMP-specific novel deleterious mutations. In all SAMP strains except SAMP8, we detected a p.R473W missense mutation in the Ldb3 gene, which has been associated with myofibrillar myopathy. In 3 SAMP strains (SAMP3, SAMP10, and SAMP11), we identified a p.R167C missense mutation in the Prx gene, in which mutations causing hereditary motor and sensory neuropathy (Dejerine-Sottas syndrome) have been identified. In SAMP6 we detected a p.S540fs frame-shift mutation in the Il4ra gene, a mutation potentially causative of ulcerative colitis and osteoporosis. Conclusions Our data indicate that different combinations of mutations in disease-causing genes may be responsible for the various phenotypes of SAMP strains. PMID:23586671

  18. Ecology, 79(1), 1998, pp. 315327 1998 by the Ecological Society of America

    E-print Network

    and some effect on egg size. There were no effects on larval body or juvenile rudiment that resembled315 Ecology, 79(1), 1998, pp. 315­327 1998 by the Ecological Society of America EFFECTS OF MATERNAL, 620 University Road, Friday Harbor, Washington 98250-9299 USA Abstract. Maternal nutritional stress

  19. Ecology Explorers

    NSDL National Science Digital Library

    This Web site from the Center for Environmental Studies at Arizona State University was developed as part of the Central Arizona-Phoenix Long-term Ecological Research Project (CAP LTER), but can be used by any classrooms interested in exploring urban ecosystems that surround them. Students and teachers learn about the scientific method and several data collection protocols that they can use right in their schoolyard. The site is attractive and easy to navigate; information is explained clearly and logically. A number of lesson plans for a variety of K-12 age groups will help teachers incorporate activities from this Web site into their classroom.

  20. Migration Ecology

    NSDL National Science Digital Library

    Alerstam, Thomas

    This site from the University of Lund, Sweden, introduces various research studies in the field of Migration Ecology including research information on "Orientation and navigation," "Flight," "Migration patterns," and "Energetics." The mission of the group is "to forward, by research and teaching, the understanding of adaptive values and evolutionary possibilities and limitations in animal migration, -flight, -orientation and energetics." Many of the group's publications are available for free as PDFs, and the site offers a simple search mechanism to help visitors find the publications they are seeking.

  1. Cross-modal priming effect based on short-term experience of ecologically unrelated audio-visual information: an event-related potential study.

    PubMed

    Liu, B; Wu, G; Meng, X

    2012-10-25

    In the present study, we aimed to identify whether cross-modal priming effect based on short-term experience of ecologically unrelated audio-visual information existed. In the experiment, we employed ecologically unrelated pictures and sounds as visual and auditory stimuli. Participants were required to learn the associations between pictures and sounds in the study phase, and then finished the following experiment adopting a cross-modal priming paradigm. The result showed that the processing of sound was facilitated by a priming picture if an audio-visual pair was presented in the study phase. Enhanced induced gamma-band activity (GBA) was also found under the Match condition, and we suggested that induced GBA reflected the association between auditory and visual information to form supra-modal representation, which is top-down modulated by short-term experience of audio-visual information. Event-related potential (ERP) analysis revealed an N400 effect under the Mismatch condition compared to the Match condition, and source reconstruction of N400 effect showed that the biggest difference of activity between two conditions was localized in middle temporal gyrus (MTG), suggesting that MTG played an important role in the mapping process of auditory information onto a temporal semantic network. PMID:22698696

  2. Evaluate and characterize mechanisms controlling transport, fate, and effects of army smokes in the aerosol wind tunnel: Transport, transformations, fate, and terrestrial ecological effects of hexachloroethane obscurant smokes

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McVeety, B.D.; Li, Shu-mei W.; McFadden, K.M.

    1989-09-01

    The terrestrial transport, chemical fate, and ecological effects of hexachloroethane (HC) smoke were evaluated under controlled wind tunnel conditions. The primary objectives of this research program are to characterize and assess the impacts of smoke and obscurants on: (1) natural vegetation characteristic of US Army training sites in the United States; (2) physical and chemical properties of soils representative of these training sites; and (3) soil microbiological and invertebrate communities. Impacts and dose/responses were evaluated based on exposure scenarios, including exposure duration, exposure rate, and sequential cumulative dosing. Key to understanding the environmental impacts of HC smoke/obscurants is establishing the importance of environmental parameters such as relative humidity and wind speed on airborne aerosol characteristics and deposition to receptor surfaces. Direct and indirect biotic effects were evaluated using five plant species and two soil types. HC aerosols were generated in a controlled atmosphere wind tunnel by combustion of hexachloroethane mixtures prepared to simulate normal pot burn rates and conditions. The aerosol was characterized and used to expose plant, soil, and other test systems. Particle sizes of airborne HC ranged from 1.3 to 2.1 {mu}m mass median aerodynamic diameter (MMAD), and particle size was affected by relative humidity over a range of 20% to 85%. Air concentrations employed ranged from 130 to 680 mg/m{sup 3}, depending on exposure scenario. Chlorocarbon concentrations within smokes, deposition rates for plant and soil surfaces, and persistence were determined. The fate of principal inorganic species (Zn, Al, and Cl) in a range of soils was assessed.

  3. Energy and ecology

    SciTech Connect

    Gates, D.M.

    1985-01-01

    The use of any renewable or nonrenewable energy form has ecological and environmental consequences. To comprehend these consequences, we must first understand the technology of each energy form: solar, biomass, coal, petroleum, nuclear, and such alternative energy sources as ocean thermal energy conversion, geothermal, wind, hydroelectric, ocean tidal, and ocean wave. The author examines the ecological principles, the food chains, and the effects of physical factors, biogeochemical cycles, and population growth. Separate chapters deal with the atmosphere, individual energy sources, carbon dioxide and climate change, electric power generation, and alternative energy sources. Intended for the lay reader, the book offers a multi-disciplinary awareness of the dangers of energy misuse and overexploitation while encouraging a sensible, sensitive stewardship. 234 references, 106 figures, 23 tables.

  4. Emphasizing the ecology in parasite community ecology

    E-print Network

    Pedersen, Amy B.

    Emphasizing the ecology in parasite community ecology Amy B. Pedersen1 and Andy Fenton2 1 Institute of parasites. However, the significance of interactions between species and the processes that shape within-host parasite communities remain unclear. Studies of parasite community ecology are often descriptive, focusing

  5. Ecological effects and management aspects of an exotic tree species: the case of lodgepole pine in Sweden

    Microsoft Academic Search

    Ola Engelmark; Kjell Sjöberg; Bengt Andersson; Ola Rosvall; Göran I. Ågren; William L. Baker; Pia Barklund; Christer Björkman; Don G. Despain; Björn Elfving; Richard A. Ennos; Margareta Karlman; Magnus F. Knecht; Dennis H. Knight; Nick J. Ledgard; Åke Lindelöw; Christer Nilsson; George F. Peterken; Sverker Sörlin; Martin T. Sykes

    2001-01-01

    The North American tree Pinus contorta var. latifolia was experimentally introduced in Sweden already in the 1920s, and has been used in Swedish forestry on a large scale since the 1970s. These plantations now cover 565,000ha, mainly in the northern area.In this paper we summarize and discuss existing ecological knowledge of this species introduction. With regard to long-term sustainability we

  6. Effect of Methodological and Ecological Approaches on Heterogeneity of Nest-Site Selection of a Long-Lived Vulture

    PubMed Central

    Moreno-Opo, Rubén; Fernández-Olalla, Mariana; Margalida, Antoni; Arredondo, Ángel; Guil, Francisco

    2012-01-01

    The application of scientific-based conservation measures requires that sampling methodologies in studies modelling similar ecological aspects produce comparable results making easier their interpretation. We aimed to show how the choice of different methodological and ecological approaches can affect conclusions in nest-site selection studies along different Palearctic meta-populations of an indicator species. First, a multivariate analysis of the variables affecting nest-site selection in a breeding colony of cinereous vulture (Aegypius monachus) in central Spain was performed. Then, a meta-analysis was applied to establish how methodological and habitat-type factors determine differences and similarities in the results obtained by previous studies that have modelled the forest breeding habitat of the species. Our results revealed patterns in nesting-habitat modelling by the cinereous vulture throughout its whole range: steep and south-facing slopes, great cover of large trees and distance to human activities were generally selected. The ratio and situation of the studied plots (nests/random), the use of plots vs. polygons as sampling units and the number of years of data set determined the variability explained by the model. Moreover, a greater size of the breeding colony implied that ecological and geomorphological variables at landscape level were more influential. Additionally, human activities affected in greater proportion to colonies situated in Mediterranean forests. For the first time, a meta-analysis regarding the factors determining nest-site selection heterogeneity for a single species at broad scale was achieved. It is essential to homogenize and coordinate experimental design in modelling the selection of species' ecological requirements in order to avoid that differences in results among studies would be due to methodological heterogeneity. This would optimize best conservation and management practices for habitats and species in a global context. PMID:22413023

  7. Improved probability of detection of ecological “surprises”

    PubMed Central

    Lindenmayer, D. B.; Likens, G. E.; Krebs, C. J.; Hobbs, R. J.

    2010-01-01

    Ecological “surprises” are defined as unexpected findings about the natural environment. They are critically important in ecology because they are catalysts for questioning and reformulating views of the natural world, help shape assessments of the veracity of a priori predictions about ecological trends and phenomena, and underpin questioning of effectiveness of resource management. Despite the importance of ecological surprises, major gaps in understanding remain about how studies might be done differently or done better to improve the ability to identify them. We outline the kinds of ecological surprises that have arisen from long-term research programs that we lead in markedly different ecosystems around the world. Based on these case studies, we identify important lessons to guide both existing studies and new investigations to detect ecological surprises more readily, better anticipate unusual ecological phenomena, and take proactive steps to plan for and alleviate “undesirable” ecological surprises. Some of these lessons include: (i) maintain existing, and instigate new, long-term studies; (ii) conduct a range of kinds of parallel and concurrent research in a given target area; (iii) better use past literature and conceptual models of the target ecosystem in posing good questions and developing hypotheses and alternative hypotheses; and (iv) increase the capacity for ecological research to take advantage of opportunities arising from major natural disturbances. We argue that the increased anticipatory capability resulting from these lessons is critical given that ecological surprises may become more prevalent because of climate change and multiple and interacting environmental stressors. PMID:21098660

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

    NASA Astrophysics Data System (ADS)

    Passeport, Elodie; Vidon, Philippe; Forshay, Kenneth J.; Harris, Lora; Kaushal, Sujay S.; Kellogg, Dorothy Q.; Lazar, Julia; Mayer, Paul; Stander, Emilie K.

    2013-02-01

    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 synthesized current knowledge about the functioning principles, performance, and cost of common EEPs used to mitigate N pollution at the watershed scale. Our review describes seven EEPs known to decrease N to help watershed managers select the most effective techniques from among the following approaches: advanced-treatment septic systems, low-impact development (LID) structures, permeable reactive barriers, treatment wetlands, riparian buffers, artificial lakes and reservoirs, and stream restoration. Our results show a broad range of N-removal effectiveness but suggest that all techniques could be optimized for N removal by promoting and sustaining conditions conducive to biological transformations (e.g., denitrification). Generally, N-removal efficiency is particularly affected by hydraulic residence time, organic carbon availability, and establishment of anaerobic conditions. There remains a critical need for systematic empirical studies documenting N-removal efficiency among EEPs and potential environmental and economic tradeoffs associated with the widespread use of these techniques. Under current trajectories of N inputs, land use, and climate change, ecological engineering alone may be insufficient to manage N in many watersheds, suggesting that N-pollution source prevention remains a critical need. Improved understanding of N-removal effectiveness and modeling efforts will be critical in building decision support tools to help guide the selection and application of best EEPs for N management.

  9. Ecological Perspectives in Teaching Research.

    ERIC Educational Resources Information Center

    Siedentop, Daryl

    2002-01-01

    Provides an overview of the field of teacher effectiveness research, describing the approaches one professor and his students have taken in their programmatic research examining teacher effectiveness from an ecological perspective of classroom life. The paper emphasizes methodologies, explaining that good data are the key to successful research,…

  10. Reproduction of Pseudocalanus newmani (Copepoda: Calanoida) is deleteriously affected by diatom blooms A field study

    NASA Astrophysics Data System (ADS)

    Halsband-Lenk, Claudia; Pierson, James J.; Leising, Andrew W.

    2005-11-01

    Copepod secondary production has traditionally been linked to the spring diatom bloom in temperate and high latitudes, but laboratory studies have recently challenged this view and have shown either reduced fecundity or viability of offspring when copepods were fed high concentrations of - mostly unialgal - diatoms. However, field evidence that diatoms affect copepod reproduction is still scarce. We analyzed the reproductive response of a common, small calanoid copepod of the boreal Pacific, Pseudocalanus newmani, to spring diatom blooms in Dabob Bay, a semi-enclosed fjord of Puget Sound, Washington, USA. Abundance patterns, egg production rates, egg hatching success, and naupliar viability of the egg-carrying copepod were examined between February and early May in the years 2002-2004. The population underwent strong variations in abundance during both years, with high abundance of all stages from February to mid-March, but dramatically decreasing individual numbers later in spring. A recovery to higher numbers occurred in July. While egg production rates were independent of chlorophyll concentrations, the reproductive success of P. newmani was negatively affected by certain phytoplankton bloom conditions. Hatching success and - more markedly - naupliar survival were reduced following peaks of Thalassiosira species that were producing anti-mitotic aldehydes, but were high during periods when phytoplankton blooms were more diverse or dominated by other prey taxa including diatoms. As a consequence, recruitment of the naupliar population was considerably affected by the Thalassiosira blooms. This study shows for the first time that the so-called diatom effect operates in nature when all prerequisites - (1) high concentration of aldehyde producers, (2) few prey alternatives, and (3) feeding of copepods on these algae - are given. However, the effect was transient in Dabob Bay and may be so in other pelagic ecosystems. It remains to discern the potential sources of mortality, such as toxicity, malnutrition, predation, and/or advection, that may have caused the strong decline of the Pseudocalanus population during April.

  11. Screening and structural evaluation of deleterious Non-Synonymous SNPs of ePHA2 gene involved in susceptibility to cataract formation.

    PubMed

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

    2012-01-01

    Age-related cataract is clinically and genetically heterogeneous disorder affecting the ocular lens, and the leading cause of vision loss and blindness worldwide. Here we screened nonsynonymous single nucleotide polymorphisms (nsSNPs) of a novel gene, EPHA2 responsible for age related cataracts. The SNPs were retrieved from dbSNP. Using I-Mutant, protein stability change was calculated. The potentially functional nsSNPs 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 EPHA2 protein was evaluated by using SWISSPDB viewer and NOMAD-Ref server. Our analysis revealed 16 SNPs as nonsynonymous out of which 6 nsSNPs, namely rs11543934, rs2291806, rs1058371, rs1058370, rs79100278 and rs113882203 were found to be least stable by I-Mutant 2.0 with DDG value of > -1.0. nsSNPs, namely rs35903225, rs2291806, rs1058372, rs1058370, rs79100278 and rs113882203 showed a highly deleterious tolerance index score of 0.00 by SIFT server. Four nsSNPs namely rs11543934, rs2291806, rs1058370 and rs113882203 were found to be probably damaging with PSIC score of ? 2. 0 by Polyp hen server. Three nsSNPs namely, rs11543934, rs2291806 and rs1058370 were found to be highly polymorphic with a risk score of 3-4 with a possible effect of Non-conservative change and splicing regulation by FASTSNP. The total energy and RMSD value was higher for the mutant-type structure compared to the native type structure. We concluded that the nsSNP namely rs2291806 as the potential functional polymorphic that is likely to have functional impact on the EPHA2 gene. PMID:22829731

  12. Ecology 2004 18, 404413

    E-print Network

    Kerkhoff, Andrew J.

    predictions and fundamental insights. EQUILIBRIUM WATER BALANCE AND THE ECOLOGICAL OPTIMALITY HYPOTHESESFunctional Ecology 2004 18, 404­413 © 2004 British Ecological Society 404 Blackwell Publishing, Ltd. An ecological evaluation of Eagleson's optimality hypotheses A. J. KERKHOFF,* S. N. MARTENS* and B. T. MILNE

  13. Ecology 2002 90, 714727

    E-print Network

    Bermingham, Eldredge

    , seed- ling establishment Journal of Ecology (2002) 90, 714­727 Introduction Limits to seed dispersal Society, Journal of Ecology, 90, 714­727 in experimental manipulations of seed dispersal, and dueJournal of Ecology 2002 90, 714­727 © 2002 British Ecological Society Blackwell Science, Ltd Role

  14. Ecology 2004 92, 372383

    E-print Network

    Moles, Angela

    , seed mass, seedling emergence, seedling establishment Journal of Ecology (2004) 92, 372-mail amoles@bio.mq.edu.au). #12;373 Seedling survival and seed size © 2004 British Ecological Society, Journal of Journal of Ecology 2004 92, 372­383 © 2004 British Ecological Society Blackwell Publishing, Ltd

  15. Toward an Ecological Economics

    Microsoft Academic Search

    J. R. Stanfield; HERMAN E. DALY

    1983-01-01

    Costanza, R. and Daly, H.E., 1987. Toward an ecological economics. Ecol. Modelling, 38: 1-7. Integrating ecology and economics is increasingly important as humanity's impact on the natural world increases. Current paradigms in both fields are too narrow (and seem to be getting narrower). This paper introduces and summarizes this special issue of Ecological Modeling devoted to ecological economics. There are

  16. Reframing the Grazing Debate: Evaluating Ecological Sustainability

    E-print Network

    Sisk, Thomas D.

    of livestock grazing in bioregional food production and the effect of that grazing on ecological sustainability estimates of meat production and water use in Arizona. To address the latter, we present data from a longReframing the Grazing Debate: Evaluating Ecological Sustainability and Bioregional Food Production

  17. Developing effective policies for the sustainable development of ecological agriculture in China: the case study of Jinshan County with a systems dynamics modelB

    Microsoft Academic Search

    Tian Shia; Roderic Gill

    This paper focuses on a search for concrete policy measures to facilitate the overall sustainability of ecological agricultural development at a county level. For this purpose, a system dynamics model (AISEEM) has been developed to explore the potential long-term ecological, economic, institutional and social interactions of ecological agricultural development through a case study of Jinshan County in China. The model

  18. Ecology, 83(10), 2002, pp. 27822797 2002 by the Ecological Society of America

    E-print Network

    Plotkin, Joshua B.

    of spatial isolation gen- erated by dispersal limitation. Disentangling the effects of habitat vs. geographic2782 Ecology, 83(10), 2002, pp. 2782­2797 2002 by the Ecological Society of America HABITAT the effects of habitat vs. geographic distance. Using floristic, topographic, and soil nutrient data from 105

  19. Mural Ecology: An Interesting Alternative or a Useful Adjunct.

    ERIC Educational Resources Information Center

    Kinchin, Ian M.

    1986-01-01

    Suggests mural ecology as an alternative to studying other habitats, providing examples of zonation patterns, food webs, effects of physical factors, and influence of man on mural communities. Also suggests incorporating these topics into ecology courses, offering ideas for field work and comparing mural to traditional ecological studies.…

  20. Reduced production of the deleterious hydroxyl free radical during the final reperfusion of isolated rabbit heart with the use of an improved sodium lactobionate-based cardioplegic medium.

    PubMed

    Charloux, C; Ishii, K; Paul, M; Loisance, D; Astier, A

    1994-01-01

    The production of free radicals during the reperfusion of hearts after prolonged ischemia might be responsible for the deleterious effects observed. Several strategies have attempted to limit this production or trap the radicals produced. This study aimed to evaluate the efficacy of a sodium lactobionate-based solution supplemented with 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, a stable nitroxide free radical, in scavenging hydroxyl radicals produced during the reperfusion of the isolated rabbit heart. 4-Hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl was administered just before the end of the storage period (6 hours) in a cardioplegic solution, either crystalloid solution or sodium lactobionate-based solution. The production of hydroxyl radicals was assessed through the production of dihydroxybenzoic acid, a reaction compound of hydroxyl radicals with salicylate. Two main isomers of dihydroxybenzoic acid were found in the coronary effluents: 2,3 and 2,5 dihydroxybenzoic acid. The production was 40-fold lower when the hearts received sodium lactobionate-based solution than when they received crystalloid solution (p < 0.001). The presence of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl had no influence on the production of hydroxyl radicals. The production of hydroxyl radicals was maximal during the first minute of the reperfusion. Iron ions, directly involved in the production of hydroxyl radicals, were shown to be complexed by sodium lactobionate in vitro. These results underlie the important role of lactobionate in the prevention of the reperfusion injury and the inefficacy of 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl to decrease the production of hydroxyl radicals. PMID:8061025

  1. Quantifying the deleterious role of strong correlations in La1 -xCaxMnO3 at the magnetocaloric transition

    NASA Astrophysics Data System (ADS)

    Turcaud, J. A.; Pereira, A. M.; Cohen, L. F.

    2015-04-01

    Here we study orthorhombic L a1 -xC axMn O3(LCMO ) where x =0.2 ,0.25 , and 0.3 measuring the magnetization, the magneto-Seebeck, and magnetovolume contraction as a function of temperature and magnetic field to examine the influence of lattice, spin, and electronic degrees of freedom. Making the assumption that these contributions are independent of each other allows us to isolate the purely magnetic contribution to the total entropy change. This is compared directly with the value predicted from a mean-field plus Bean-Rodbell model. The model allows the first order character of the transition to be determined, as well as assigning numeric values to the number of magnetic ions that make up preformed magnetic clusters, and to the magnitude of the spread in TC. We quantify how the clusters, the TC spread values, and the electronic contribution, impact deleteriously on the available entropy change in fixed magnetic field, as the first order nature of the transition strengthens.

  2. Selective propagation of functional mtDNA during oogenesis restricts the transmission of a deleterious mitochondrial variant

    PubMed Central

    Hill, Jahda H.; Chen, Zhe; Xu, Hong

    2014-01-01

    Though mitochondrial DNA is prone to mutation and few mtDNA repair mechanisms exist1, crippling mitochondrial mutations are exceedingly rare2. Recent studies demonstrated strong purifying selection in the mouse female germline3,4. However, the mechanisms underlying the positive selection of healthy mitochondria remain to be elucidated. We visualized mtDNA replication during Drosophila oogenesis. We found that mtDNA replication commenced prior to oocyte determination during the late germarium stage, and was dependent on mitochondrial fitness. We isolated a temperature-sensitive lethal mtDNA mutation, mt:CoIT300I, which displayed reduced mtDNA replication in the germarium at the restrictive temperature. Additionally, the frequency of mt:CoIT300I in heteroplasmic flies was decreased both through oogenesis and over multiple generations at the restrictive temperature. Furthermore, we determined that selection against mt:CoIT300I overlaps with the timing of selective replication of mtDNA in the germarium. These findings establish a previously uncharacterized developmental mechanism for selective amplification of healthy mtDNA, which may be evolutionarily conserved to limit transmission of deleterious mutations. PMID:24614072

  3. Exploration of deleterious single nucleotide polymorphisms in the components of human P bodies: an in silico approach.

    PubMed

    Venkatesh, Thejaswini; Suresh, Padmanaban S

    2013-10-10

    P bodies are 100-300 nm sized organelles involved in mRNA silencing and degradation. A total of 60 human proteins have been reported to localize to P bodies. Several human SNPs contribute to complex diseases by altering the structure and function of the proteins. Also, SNPs alter various transcription factors binding, splicing and miRNA regulatory sites. Owing to the essential functions of P bodies in mRNA regulation, we explored computationally the functional significance of SNPs in 7 P body components such as XRN1, DCP2, EDC3, CPEB1, GEMIN5, STAU1 and TRIM71. Computational analyses of non-synonymous SNPs of these components was initiated using well utilized publicly available software programs such as the SIFT, followed by PolyPhen, PANTHER, MutPred, I-Mutant-2.0 and PhosSNP 1.0. Functional significance of noncoding SNPs in the regulatory regions were analysed using FastSNP. Utilizing miRSNP database, we explored the role of SNPs in the context that alters the miRNA binding sites in the above mentioned genes. Our in silico studies have identified various deleterious SNPs and this cataloguing is essential and gives first hand information for further analysis by in vitro and in vivo methods for a better understanding of maintenance, assembly and functional aspects of P bodies in both health and disease. PMID:23892092

  4. Seeking balance: decision support needs of women without cancer and a deleterious BRCA1 or BRCA2 mutation.

    PubMed

    Underhill, Meghan L; Crotser, Cheryl B

    2014-06-01

    Recommendations for women with a deleterious BRCA1 or BRCA2 gene mutation include complex medical approaches related to cancer risk reduction and detection. Current science has not yet fully elucidated decision support needs that women face when living with medical consequences associated with known hereditary cancer risk. The purpose of this study was to describe health communication and decision support needs in healthy women with BRCA1/2 gene mutations. The original researchers completed an interpretive secondary qualitative data analysis of 23 phenomenological narratives collected between 2008 and 2010. The Ottawa Decision Support and Patient Centered Communication frameworks guided the study design and analysis. Women described a pattern wherein breast and ovarian cancer risk, health related recommendations and decisions, and personal values were prioritized over time based on life contexts. Knowing versus acting on cancer risk was not a static process but an ongoing balancing act of considering current and future personal and medical values, further compounded by the complexity of recommendations. Women shared stories of anticipatory, physical and psychosocial consequences of the decision making experience. The findings have potential to generate future research questions and guide intervention development. Importantly, findings indicate a need for ongoing, long-term, support from genetics professionals and decision support interventions, which challenges the current practice paradigm. PMID:24271037

  5. A deleterious effect associated with UNH159 is attenuated in twin embryos of an inbred line of tilapia (Oreochromis aureus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Offspring of a highly inbred gynogenetic line of Oreochromis aureus displayed 12-fold increase in twinning rate compared to the outbred population. Asymmetric conjoined twins which consist of a normal embryo attached to a malformed-atrophic twin were frequently encountered in both gynogenetic (90.7%...

  6. Deleterious effects of a nonPST bioactive compound(s) from Alexandrium tamarense on bivalve hemocytes

    E-print Network

    Brest, Université de

    by other harmful algae are known to cause immobilization, cellular deformation and lysis of co to be ingested whole by hemocytes and would most likely be exposed to intracellular toxins only after the algae are concentrated by the bivalves as they feed during algal blooms, pose a serious health risk to human consumers

  7. Groundwater-ocean interaction and its effects on coastal ecological processes - are there groundwater-dependant ecosystems in the coastal zone?

    NASA Astrophysics Data System (ADS)

    Stieglitz, T. C.

    2013-05-01

    Hydrological land-ocean connectivity is an important driver of coastal ecosystems. Rivers are obvious and visible pathways for terrestrial runoff. The critical role of surface water discharge from rivers to coastal ecosystems has been well documented. Hidden from view, 'downstream' effects of coastal (supra-tidal, intertidal and submarine) groundwater discharge are far less well understood. Whilst hydrological and geochemical processes associated with coastal groundwater discharge have received an increasing amount of scientific attention over the past decade or so, the effects of groundwater flow on productivity, composition, diversity and functioning of coastal ecosystems along the world's shorelines have received little attention to date. Coastal groundwater discharge includes both terrestrial (fresh) groundwater fluxes and the recirculation of seawater through sediments, analogous to hyporheic flow in rivers. I will present an overview over relevant coastal hydrological processes, and will illustrate their ecological effects on examples from diverse tropical coastal ecosystems, e.g. (1) perennial fresh groundwater discharge from coastal sand dune systems permitting growth of freshwater-dependent vegetation in the intertidal zone of the Great Barrier Reef (Australia), (2) recirculation of seawater through mangrove forest floors directly affecting tree health and providing a pathway for carbon export from these ecosystems, (3) the local hydrology of groundwater-fed coastal inlets on Mexico's Yucatan peninsula affecting the movement behaviour of and habitat use by the queen conch Strombus gigas, an economically important species in the Caribbean region. These examples for hydrological-ecological coupling in the coastal zone invite the question if we should not consider these coastal ecosystems to be groundwater-dependent, in analogy to groundwater-dependency in freshwater aquatic systems.

  8. Journal of Applied Ecology 2006

    E-print Network

    Elmore, Andrew J.

    Ecological Society Blackwell Publishing Ltd Decline in alkali meadow vegetation cover in California: the effects of groundwater extraction and drought ANDREW J. ELMORE,* SARA J. MANNING, JOHN F. MUSTARD vegetation is threatened by groundwater extraction. This is particularly true for alkali meadow vegetation

  9. Social Studies: Ecology and Survival.

    ERIC Educational Resources Information Center

    Liftin, Elaine

    Designed as an elective course of study for grades seven through nine, this curriculum guide provides a study of the political, economic, and social aspects of ecological problems in the community, state, or nation. The focus is on the causes and effects of pollution and alternative courses of governmental and student (citizen) action. A suggested…

  10. Health Behavior in Ecological Context

    ERIC Educational Resources Information Center

    Simons-Morton, Bruce

    2013-01-01

    Health is best understood within an ecological context. Accordingly, health promotion involves processes that foster supportive environments and healthful behavior. Thus, effective health promotion programs are typically multilevel, focusing not only on the population at risk but also on the environmental conditions that contribute so importantly…

  11. High concentrations of protein test substances may have non-toxic effects on Daphnia magna: implications for regulatory study designs and ecological risk assessments for GM crops.

    PubMed

    Raybould, Alan; Burns, Andrea; Hamer, Mick

    2014-01-01

    Laboratory testing for possible adverse effects of insecticidal proteins on non-target organisms (NTOs) is an important part of many ecological risk assessments for regulatory decision-making about the cultivation of insect-resistant genetically modified (IRGM) crops. To increase confidence in the risk assessments, regulatory guidelines for effects testing specify that representative surrogate species for NTOs are exposed to concentrations of insecticidal proteins that are in excess of worst-case predicted exposures in the field. High concentrations in effects tests are achieved by using protein test substances produced in microbes, such as Escherichia coli. In a study that exposed Daphnia magna to a single high concentration of a microbial test substance containing Vip3Aa20, the insecticidal protein in MIR162 maize, small reductions in growth were observed. These effects were surprising as many other studies strongly suggest that the activity of Vip3Aa20 is limited to Lepidoptera. A plausible explanation for the effect on growth is that high concentrations of test substance have a non-toxic effect on Daphnia, perhaps by reducing its feeding rate. A follow-up study tested that hypothesis by exposing D. magna to several concentrations of Vip3Aa20, and a high concentration of a non-toxic protein, bovine serum albumin (BSA). Vip3Aa20 and BSA had sporadic effects on the reproduction and growth of D. magna. The pattern of the effects suggests that they result from non-toxic effects of high concentrations of protein, and not from toxicity. The implications of these results for regulatory NTO effects testing and ERA of IRGM crops are discussed. PMID:25523175

  12. Three dimensional printing as an effective method of producing anatomically accurate models for studies in thermal ecology.

    PubMed

    Watson, Charles M; Francis, Gamal R

    2015-07-01

    Hollow copper models painted to match the reflectance of the animal subject are standard in thermal ecology research. While the copper electroplating process results in accurate models, it is relatively time consuming, uses caustic chemicals, and the models are often anatomically imprecise. Although the decreasing cost of 3D printing can potentially allow the reproduction of highly accurate models, the thermal performance of 3D printed models has not been evaluated. We compared the cost, accuracy, and performance of both copper and 3D printed lizard models and found that the performance of the models were statistically identical in both open and closed habitats. We also find that 3D models are more standard, lighter, durable, and inexpensive, than the copper electroformed models. PMID:25965016

  13. Evolutionary ecology. Cycles of species replacement emerge from locally induced maternal effects on offspring behavior in a passerine bird.

    PubMed

    Duckworth, Renée A; Belloni, Virginia; Anderson, Samantha R

    2015-02-20

    An important question in ecology is how mechanistic processes occurring among individuals drive large-scale patterns of community formation and change. Here we show that in two species of bluebirds, cycles of replacement of one by the other emerge as an indirect consequence of maternal influence on offspring behavior in response to local resource availability. Sampling across broad temporal and spatial scales, we found that western bluebirds, the more competitive species, bias the birth order of offspring by sex in a way that influences offspring aggression and dispersal, setting the stage for rapid increases in population density that ultimately result in the replacement of their sister species. Our results provide insight into how predictable community dynamics can occur despite the contingency of local behavioral interactions. PMID:25700519

  14. The ecology of religious beliefs.

    PubMed

    Botero, Carlos A; Gardner, Beth; Kirby, Kathryn R; Bulbulia, Joseph; Gavin, Michael C; Gray, Russell D

    2014-11-25

    Although ecological forces are known to shape the expression of sociality across a broad range of biological taxa, their role in shaping human behavior is currently disputed. Both comparative and experimental evidence indicate that beliefs in moralizing high gods promote cooperation among humans, a behavioral attribute known to correlate with environmental harshness in nonhuman animals. Here we combine fine-grained bioclimatic data with the latest statistical tools from ecology and the social sciences to evaluate the potential effects of environmental forces, language history, and culture on the global distribution of belief in moralizing high gods (n = 583 societies). After simultaneously accounting for potential nonindependence among societies because of shared ancestry and cultural diffusion, we find that these beliefs are more prevalent among societies that inhabit poorer environments and are more prone to ecological duress. In addition, we find that these beliefs are more likely in politically complex societies that recognize rights to movable property. Overall, our multimodel inference approach predicts the global distribution of beliefs in moralizing high gods with an accuracy of 91%, and estimates the relative importance of different potential mechanisms by which this spatial pattern may have arisen. The emerging picture is neither one of pure cultural transmission nor of simple ecological determinism, but rather a complex mixture of social, cultural, and environmental influences. Our methods and findings provide a blueprint for how the increasing wealth of ecological, linguistic, and historical data can be leveraged to understand the forces that have shaped the behavior of our own species. PMID:25385605

  15. Effects of season and agro-ecological zone on the microbial quality of raw milk along the various levels of the value chain in Uganda.

    PubMed

    Grimaud, Patrice; Sserunjogi, Mohamed; Wesuta, Milton; Grillet, Nelly; Kato, Moses; Faye, Bernard

    2009-08-01

    Dairy production in Uganda is pasture-based and traditional Ankole cattle make up 80% of the cattle herd, reared in both pastoral and agro-pastoral ecological zones. Regardless of the zone, milk quality is lowest in production basin during the dry season when ambient temperatures are highest and water is scarce. Poor hygiene and quality management contributed to the deterioration of raw milk quality during its storage and delivery to the final consumer, and concealed the seasonal effect when milk reached urban consumption areas. Poor milk quality is a challenge for the Ugandan Dairy Development Authorities who wish to make the milk value chain safe. This study provides baseline information for the implementation of an HACCP-based system to ensure the hygienic quality of milk from the farm to the market place. PMID:19016339

  16. An Ecological Momentary Assessment of the Effects of Weight and Shape Social Comparisons on Women With Eating Pathology, High Body Dissatisfaction, and Low Body Dissatisfaction

    PubMed Central

    Leahey, Tricia M.; Crowther, Janis H.; Ciesla, Jeffrey A.

    2012-01-01

    This research examined the effects of naturally occurring appearance comparisons on women’s affect, body satisfaction, and compensatory cognitions and behaviors. Using ecological momentary assessment, women with high body dissatisfaction and eating pathology (EPHB), high body dissatisfaction (HB), or low body dissatisfaction (LB) recorded their reactions to appearance-focused social comparisons. EPHB and HB women made more upward appearance comparisons than LB women. All women experienced negative emotions and cognitions after upward comparisons, including increased guilt, body dissatisfaction, and thoughts of dieting. EPHB women were most negatively affected by comparisons; they experienced more intense negative emotions, more thoughts of dieting/exercising, and an increase in eating-disordered behavior after upward comparisons. HB women experienced more negative affective consequences and thoughts of dieting than LB women. Results are consistent with social comparison theory and provide important information that may be used to inform eating disorder treatment and prevention efforts. PMID:21496506

  17. Effects of Local Habitat Variation on the Behavioral Ecology of Two Sympatric Groups of Brown Howler Monkey (Alouatta clamitans).

    PubMed

    Jung, Linda; Mourthe, Italo; Grelle, Carlos E V; Strier, Karen B; Boubli, Jean P

    2015-01-01

    Although the brown howler monkey (Alouatta clamitans) is a relatively well-studied Neotropical primate, its behavioral and dietary flexibility at the intra-population level remains poorly documented. This study presents data collected on the behavior and ecology of two closely located groups of brown howlers during the same period at the RPPN Feliciano Miguel Abdala in southeastern Brazil. One group occupied a primary valley habitat, henceforth the Valley Group (VG), and the other group occupied a regenerating hillside habitat, the Hill Group (HG). We hypothesized differences in the behavior and ecological parameters between these sympatric groups due to the predicted harsher conditions on the hillside, compared to the valley. We measured several habitat parameters within the home range of both groups and collected data on the activity budget, diet and day range lengths, from August to November 2005, between dawn and dusk. In total, behavioral data were collected for 26 (318 h) and 28 (308 h) sampling days for VG and HG, respectively. As we predicted, HG spent significantly more time feeding and consumed less fruit and more leaves than VG, consistent with our finding that the hillside habitat was of lower quality. However, HG also spent less time resting and more time travelling than VG, suggesting that the monkeys had to expend more time and energy to obtain high-energy foods, such as fruits and flowers that were more widely spaced in their hill habitat. Our results revealed that different locations in this forest vary in quality and raise the question of how different groups secure their home ranges. Fine-grained comparisons such as this are important to prioritize conservation and management areas within a reserve. PMID:26147203

  18. Effects of Local Habitat Variation on the Behavioral Ecology of Two Sympatric Groups of Brown Howler Monkey (Alouatta clamitans)

    PubMed Central

    Grelle, Carlos E. V.; Strier, Karen B.; Boubli, Jean P.

    2015-01-01

    Although the brown howler monkey (Alouatta clamitans) is a relatively well-studied Neotropical primate, its behavioral and dietary flexibility at the intra-population level remains poorly documented. This study presents data collected on the behavior and ecology of two closely located groups of brown howlers during the same period at the RPPN Feliciano Miguel Abdala in southeastern Brazil. One group occupied a primary valley habitat, henceforth the Valley Group (VG), and the other group occupied a regenerating hillside habitat, the Hill Group (HG). We hypothesized differences in the behavior and ecological parameters between these sympatric groups due to the predicted harsher conditions on the hillside, compared to the valley. We measured several habitat parameters within the home range of both groups and collected data on the activity budget, diet and day range lengths, from August to November 2005, between dawn and dusk. In total, behavioral data were collected for 26 (318 h) and 28 (308 h) sampling days for VG and HG, respectively. As we predicted, HG spent significantly more time feeding and consumed less fruit and more leaves than VG, consistent with our finding that the hillside habitat was of lower quality. However, HG also spent less time resting and more time travelling than VG, suggesting that the monkeys had to expend more time and energy to obtain high-energy foods, such as fruits and flowers that were more widely spaced in their hill habitat. Our results revealed that different locations in this forest vary in quality and raise the question of how different groups secure their home ranges. Fine-grained comparisons such as this are important to prioritize conservation and management areas within a reserve. PMID:26147203

  19. Ecological Complexity of Coral Recruitment Processes: Effects of Invertebrate Herbivores on Coral Recruitment and Growth Depends Upon Substratum Properties and Coral Species

    PubMed Central

    Davies, Sarah W.; Matz, Mikhail V.; Vize, Peter D.

    2013-01-01

    Background The transition from planktonic planula to sessile adult corals occurs at low frequencies and post settlement mortality is extremely high. Herbivores promote settlement by reducing algal competition. This study investigates whether invertebrate herbivory might be modulated by other ecological factors such as substrata variations and coral species identity. Methodology/Principal Findings The experiment was conducted at the Flower Garden Banks, one of the few Atlantic reefs not experiencing considerable degradation. Tiles of differing texture and orientation were kept in bins surrounded by reef (24 m). Controls contained no herbivores while treatment bins contained urchins (Diadema antillarum) or herbivorous gastropods (Cerithium litteratum). Juvenile corals settling naturally were monitored by photography for 14 months to evaluate the effects of invertebrate herbivory and substratum properties. Herbivory reduced algae cover in urchin treatments. Two genera of brooding coral juveniles were observed, Agaricia and Porites, both of which are common but not dominant on adjacent reef. No broadcast spawning corals were observed on tiles. Overall, juveniles were more abundant in urchin treatments and on vertical, rough textured surfaces. Although more abundant, Agaricia juveniles were smaller in urchin treatments, presumably due to destructive overgrazing. Still, Agaricia growth increased with herbivory and substrata texture-orientation interactions were observed with reduced growth on rough tiles in control treatments and increased growth on vertical tiles in herbivore treatments. In contrast to Agaricia, Porites juveniles were larger on horizontal tiles, irrespective of herbivore treatment. Mortality was affected by substrata orientation with vertical surfaces increasing coral survival. Conclusions/Significance We further substantiate that invertebrate herbivores play major roles in early settlement processes of corals and highlight the need for deeper understanding of ecological interactions modulating these effects. The absence of broadcast-spawning corals, even on a reef with consistently high coral cover, continues to expose the recruitment failure of these reef-building corals throughout the Caribbean. PMID:24039807

  20. Genetic mosaic analysis of a deleterious mitochondrial DNA mutation in Drosophila reveals novel aspects of mitochondrial regulation and function

    PubMed Central

    Chen, Zhe; Qi, Yun; French, Stephanie; Zhang, Guofeng; Garcia, Raúl Covian; Balaban, Robert; Xu, Hong

    2015-01-01

    Various human diseases are associated with mitochondrial DNA (mtDNA) mutations, but heteroplasmy—the coexistence of mutant and wild-type mtDNA—complicates their study. We previously isolated a temperature-lethal mtDNA mutation in Drosophila, mt:CoIT300I, which affects the cytochrome c oxidase subunit I (CoI) locus. In the present study, we found that the decrease in cytochrome c oxidase (COX) activity was ascribable to a temperature-dependent destabilization of cytochrome a heme. Consistently, the viability of homoplasmic flies at 29°C was fully restored by expressing an alternative oxidase, which specifically bypasses the cytochrome chains. Heteroplasmic flies are fully viable and were used to explore the age-related and tissue-specific phenotypes of mt:CoIT300I. The proportion of mt:CoIT300I genome remained constant in somatic tissues along the aging process, suggesting a lack of quality control mechanism to remove defective mitochondria containing a deleterious mtDNA mutation. Using a genetic scheme that expresses a mitochondrially targeted restriction enzyme to induce tissue-specific homoplasmy in heteroplasmic flies, we found that mt:CoIT300I homoplasmy in the eye caused severe neurodegeneration at 29°C. Degeneration was suppressed by improving mitochondrial Ca2+ uptake, suggesting that Ca2+ mishandling contributed to mt:CoIT300I pathogenesis. Our results demonstrate a novel approach for Drosophila mtDNA genetics and its application in modeling mtDNA diseases. PMID:25501370