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1

Quantifying dominance and deleterious effect on human disease genes  

PubMed Central

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

Osada, Naoki; Mano, Shuhei; Gojobori, Jun

2009-01-01

2

Effect of deleterious mutations on life span in Drosophila melanogaster.  

PubMed

Evolutionary theories of aging assume that the accumulation of deleterious mutations will reduce life span. We tested this assumption in Drosophila melanogaster by a newly designed mating scheme, in which mutations accumulate on the Binscy balancer X chromosome in heterozygous females in the absence of selection and recombination. We found that the life span of Binscy/RY(L) males from this cross decreased faster than the life span of their sibling controls over time in two of three runs, and that there was an age-specific increase in mortality in the Binscy/RY(L) males with time in one of three runs. Therefore, the accumulation of deleterious mutations can decrease life span by increasing fragility and can cause age-specific changes in mortality. These results support the evolutionary theory of aging. PMID:17234817

Gong, Yi; Thompson, James N; Woodruff, R C

2006-12-01

3

Dominance Effects of Deleterious and Beneficial Mutations in a Single Gene of the RNA Virus ?6  

PubMed Central

Most of our knowledge of dominance stems from studies of deleterious mutations. From these studies we know that most deleterious mutations are recessive, and that this recessivity arises from a hyperbolic relationship between protein function (i.e., protein concentration or activity) and fitness. Here we investigate whether this knowledge can be used to make predictions about the dominance of beneficial and deleterious mutations in a single gene. We employed a model system – the bacteriophage ?6 – that allowed us to generate a collection of mutations in haploid conditions so that it was not biased toward either dominant beneficial or recessive deleterious mutations. Screening for the ability to infect a bacterial host that does not permit infection by the wildtype ?6, we generated a collection of mutations in P3, a gene involved in attachment to the host and in phage particle assembly. The resulting collection contained mutations with both deleterious and beneficial effects on fitness. The deleterious mutations in our collection had additive effects on fitness and the beneficial mutations were recessive. Neither of these observations were predicted from previous studies of dominance. This pattern is not consistent with the hyperbolic (diminishing returns) relationship between protein function and fitness that is characteristic of enzymatic genes, but could have resulted from a curve of increasing returns.

Joseph, Sarah B.; Peck, Kayla M.; Burch, Christina L.

2014-01-01

4

Simvastatin has deleterious effects on human first trimester placental explants  

Microsoft Academic Search

BACKGROUND: Statins inhibit 3-hydroxy-3-methylglutaryl coenzyme-A reductase (HMG-CoA reductase), the rate-limiting enzyme of the mevalonate pathway, and have been used successfully in the treatment of hypercholester- olaemia. Animal models have provided evidence for the teratogenic effects of statins on pregnancy outcome. Thus statins are contraindicated during pregnancy. However, conflicting data are available from inadvertent use of statins in human pregnancy. Therefore

I. Kenis; S. Tartakover-Matalon; N. Cherepnin; L. Drucker; A. Fishman; M. Pomeranz; M. Lishner

2005-01-01

5

Deleterious effects of magnesium intoxication upon the domestic broiler chick  

SciTech Connect

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.

Lee, S.R.

1984-01-01

6

Sildenafil citrate attenuates the deleterious effects of elevated ammonia.  

PubMed

Ammonia is a bi-product of protein metabolism in the body. It is able to cross the blood-brain barrier and elevated ammonia levels are toxic to the brain. Rats with hyperammonemia showed impaired learning ability and impaired function of the glutamate-nitric oxide-cyclic guanosine monophosphate (glutamate-NO-cGMP) pathway in the brain. Chronic treatment with sildenafil restored learning ability. We therefore tested the hypothesis that sildenafil has a protective effect on the brains of hyperammonemic rats. Hyperammonemia was induced in male rats by daily intraperitoneal (i.p.) injection of ammonium chloride (100?mg/kg body weight) for 8 weeks. Sildenafil citrate was administered intraperitoneally (10?mg/kg body weight/3 days) for 8 weeks. Treatment with sildenafil resulted in a significant reduction in plasma liver enzymes, lipid profile as well as brain lipid peroxidation and caspase-3 mRNA. Meanwhile, plasma NO as well as cGMP, antioxidants and endothelial nitric oxide synthase (eNOS) gene expression were significantly elevated in the brains of hyperammonemic rats. Our results showed that sildenafil exerts a protective effect on the brain by reversing oxidative stress during hyperammonemia and this could be due to (i) cytoprotective, antioxidant and anti-apoptotic effects (ii) increasing cGMP and enhancing the proper metabolism of fats which could suppress oxygen radical generation and thus preventing oxidative damage in the brain. The exact protective mechanism of sildenafil has to be still investigated and further studies are warranted. Consequently, therapeutic modulation of the NO/cGMP pathway might have important clinical applications to improve brain functions in patients with hyperammonemia or clinical hepatic encephalopathy. PMID:23343352

Arafa, Manar H; Atteia, Hebatallah H

2013-07-01

7

Deleterious effects of diluted povidone-iodine on articular cartilage.  

PubMed

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

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

2013-06-01

8

Deleterious Effects of Mycotoxin Combinations Involving Ochratoxin A  

PubMed Central

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

Klaric, Maja Segvic; Rasic, Dubravka; Peraica, Maja

2013-01-01

9

Deleterious effects of nonthermal electrons in shock ignition concept  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

10

Deleterious effects of nonthermal electrons in shock ignition concept.  

PubMed

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

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

2014-03-01

11

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

ERIC Educational Resources Information Center

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)

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

2001-01-01

12

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

Microsoft Academic Search

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

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

2011-01-01

13

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

PubMed Central

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.

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

2011-01-01

14

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

PubMed

• Reductions in plant growth as a result of salinity are of global importance in natural and agricultural landscapes. • Short-term (48-h) solution culture experiments studied 404 treatments with seedlings of cowpea (Vigna unguiculata cv Caloona) to examine the multiple deleterious effects of calcium (Ca), magnesium (Mg), sodium (Na) or potassium (K). • Growth was poorly related to the ion activities in the bulk solution, but was closely related to the calculated activities at the outer surface of the plasma membrane, {I(z)}?°. The addition of Mg, Na or K may induce Ca deficiency in roots by driving {Ca²+}?° to < 1.6 mM. Shoots were more sensitive than roots to osmolarity. Specific ion toxicities reduced root elongation in the order Ca²+ > Mg²+ > Na+ > K+. The addition of K and, to a lesser extent, Ca alleviated the toxic effects of Na. Thus, Ca is essential but may also be intoxicating or ameliorative. • The data demonstrate that the short-term growth of cowpea seedlings in saline solutions may be limited by Ca deficiency, osmotic effects and specific ion toxicities, and K and Ca alleviate Na toxicity. A multiple regression model related root growth to osmolarity and {I(z)}?° (R²=0.924), allowing the quantification of their effects. PMID:21118262

Kopittke, Peter M; Blamey, F Pax C; Kinraide, Thomas B; Wang, Peng; Reichman, Suzie M; Menzies, Neal W

2011-03-01

15

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

PubMed

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

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

2012-03-17

16

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

PubMed

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

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

2009-12-01

17

Metformin reverts deleterious effects of advanced glycation end-products (AGEs) on osteoblastic cells.  

PubMed

Advanced glycation endproducts (AGEs) are implicated in the complications of diabetes and ageing, affecting several tissues, including bone. Metformin, an insulin-sensitizer drug, reduces the risk of life-threatening macrovascular complications. We have evaluated the hypothesis that metformin can abrogate AGE-induced deleterious effects in osteoblastic cells in culture. In two osteoblast-like cell lines (UMR106 and MC3T3E1), AGE-modified albumin induced cell death, caspase-3 activity, altered intracellular oxidative stress and inhibited alkaline phosphatase activity. Metformin-treatment of osteoblastic cells prevented these AGE-induced alterations. We also assessed the expression of AGE receptors as a possible mechanism by which metformin could modulate the action of AGEs. AGEs-treatment of osteoblast-like cells enhanced RAGE protein expression, and this up-regulation was prevented in the presence of metformin. Although the precise mechanisms involved in metformin signaling are still elusive, our data implicate the AGE-RAGE interaction in the modulation of growth and differentiation of osteoblastic cells. PMID:18273753

Schurman, L; McCarthy, A D; Sedlinsky, C; Gangoiti, M V; Arnol, V; Bruzzone, L; Cortizo, A M

2008-06-01

18

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

PubMed

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

Dellis, A T; Kominis, I K

2012-03-01

19

Long-term consumption of a carbohydrate-restricted diet does not induce deleterious metabolic effects.  

PubMed

Carbohydrate (CHO)-restricted diets have been recommended for weight loss and to prevent obesity, but their long-term effects have not been fully elucidated. This study was designed to evaluate the effect of long-term (>1 year) consumption of a low-CHO high-fat diet ("The optimal diet," developed by Dr Kwa?niewski referenced herein) on lipid profile, glycemic control, and cardiovascular disease risk factors in healthy subjects. Of 31 "optimal" dieters enrolled in the study (17 women and 14 men, aged 51.7+/-16.6 years), 22 declared adherence to the diet for more than 3 years. Average energy intake and principal nutrients consumed were assessed from 6-day dietary records provided by the participants. In most dieters, concentrations of beta-hydroxybutyrate, free fatty acids, total cholesterol, and low-density lipoprotein cholesterol exceeded the upper limits of the reference ranges for nonstarved subjects. The metabolic profiles of most subjects were positive for several indicators, including relatively low concentrations of triacylglycerols, high levels of high-density lipoprotein cholesterol (HDL-C), and normal ratios of low-density lipoprotein cholesterol/HDL-C and total cholesterol/HDL-C. In most subjects, plasma concentrations of glucose, insulin, glucagon, cortisol, homocysteine, glycerol, and C-reactive protein were within reference ranges. Notably, in all but one subject, the homeostasis model assessment index of insulin resistance remained below the threshold for diagnosis of insulin resistance. These results indicate that long-term (>1 year) compliance with a low-CHO high-fat "optimal diet" does not induce deleterious metabolic effects and does not increase the risk for cardiovascular disease, as evidenced by maintenance of adequate glycemic control and relatively low values for conventional cardiovascular risk factors. PMID:19083495

Grieb, Pawe?; K?apci?ska, Barbara; Smol, Ewelina; Pilis, Tomasz; Pilis, Wies?aw; Sadowska-Krepa, Ewa; Sobczak, Andrzej; Bartoszewicz, Zbigniew; Nauman, Janusz; Sta?czak, Kinga; Langfort, Józef

2008-12-01

20

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

ERIC Educational Resources Information Center

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

Hall, Susan E.

2011-01-01

21

Deleterious effects of khat addiction on semen parameters and sperm ultrastructure.  

PubMed

The semen parameters and sperm ultrastructural morphology have been described in semen samples from two groups of Yemeni subjects. The first 'exposed' group comprised 65 khat addicts, while the second control group included 50 non-khat addict subjects. The mean age was 39.94 +/- 13.85 and 35.72 +/- 11.35 years in the exposed and control groups respectively, without a significant difference. The mean duration of khat addiction among the addicts was 25.34 +/- 12.96 years (range 6.00-48.00). Statistically significant differences were detected between the semen parameters of the two groups. Such parameters, including semen volume, sperm count, sperm motility, motility index and percentage of normal spermatozoa, were lower among addicts. Significant negative correlation was also found between the duration of khat consumption and all semen parameters (r ranged from -0.30 to -0.74). At the transmission electron microscopy level, a counting system was incorporated to compare the numbers of normal spermatozoa with deformed and dead spermatozoa in ultrathin plastic sections. The total mean percentage of deformed spermatozoa was approximately 65%. Different patterns of sperm deformation were demonstrated, and included both the head and flagella in complete spermatozoa, aflagellate heads, headless flagella and multiple heads and flagella. Deformed heads showed aberrated nuclei with immature nuclear chromatin and polymorphic intranuclear inclusions; these were associated with acrosomal defects. The deformed flagella demonstrated numeric aberrations of the axonemal 9 + 2 configuration and structural defects of their associated elements. Persistent cytoplasmic droplets were observed frequently. This study has shown for the first time the deleterious effects of khat addiction on semen parameters in general and sperm morphology in particular of all addicts, especially those who have consumed khat for longer periods of time. PMID:8530655

el-Shoura, S M; Abdel Aziz, M; Ali, M E; el-Said, M M; Ali, K Z; Kemeir, M A; Raoof, A M; Allam, M; Elmalik, E M

1995-09-01

22

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

PubMed Central

We recently showed that a week-long, high-fat diet reduced whole body exercise efficiency in sedentary men by >10% (Edwards LM, Murray AJ, Holloway CJ, Carter EE, Kemp GJ, Codreanu I, Brooker H, Tyler DJ, Robbins PA, Clarke K. FASEB J 25: 1088–1096, 2011). To test if a similar dietary regime would blunt whole body efficiency in endurance-trained men and, as a consequence, hinder aerobic exercise performance, 16 endurance-trained men were given a short-term, high-fat (70% kcal from fat) and a moderate carbohydrate (50% kcal from carbohydrate) diet, in random order. Efficiency was assessed during a standardized exercise task on a cycle ergometer, with aerobic performance assessed during a 1-h time trial and mitochondrial function later measured using 31P-magnetic resonance spectroscopy. The subjects then underwent a 2-wk wash-out period, before the study was repeated with the diets crossed over. Muscle biopsies, for mitochondrial protein analysis, were taken at the start of the study and on the 5th day of each diet. Plasma fatty acids were 60% higher on the high-fat diet compared with moderate carbohydrate diet (P < 0.05). However, there was no change in whole body efficiency and no change in mitochondrial function. Endurance exercise performance was significantly reduced (P < 0.01), most probably due to glycogen depletion. Neither diet led to changes in citrate synthase, ATP synthase, or mitochondrial uncoupling protein 3. We conclude that prior exercise training blunts the deleterious effect of short-term, high-fat feeding on whole body efficiency.

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

2011-01-01

23

Deleterious cognitive and motoric effects of haloperidol in an adolescent with cerebral palsy: a case report.  

PubMed

This case report describes a 15-year-old male patient with spastic diplegic cerebral palsy, Gross Motor Function Classification System Level III, who developed severe new cognitive and motoric impairments after the administration of haloperidol. He received this dopamine antagonist and typical antipsychotic medication for an acute postoperative episode of agitation. He improved when he received the dopamine agonists amantadine and carbidopa/levodopa. This case suggests that dopamine blockade may be deleterious for individuals with cerebral palsy. Potential explanations for the events observed in this case are also presented. PMID:24332231

Mortimer, Diane; Gelfius, Carl D; Potts, Michelle A

2013-12-01

24

Preinoculation of lettuce and onion with VA mycorrhizal fungi reduces deleterious effects of soil salinity  

Microsoft Academic Search

The hypothesis that inoculation of transplants with vesicular-arbuscular mycorrhizal (VAM) fungi before planting into saline soils alleviates salt effects on growth and yield was tested on lettuce (Lactuca sativa L.) and onion (Allium cepa L.). A second hypothesis was that fungi isolated from saline soil are more effective in counteracting salt effects than those from nonsaline soil. VAM fungi from

Isabella C. Cantrell; Robert G. Linderman

2001-01-01

25

Skeletal site-specific effects of whole body vibration in mature rats: from deleterious to beneficial frequency-dependent effects.  

PubMed

Whole body vibration (WBV) is receiving increasing interest as an anti-osteoporotic prevention strategy. In this context, selective effects of different frequency and acceleration magnitude modalities on musculoskeletal responses need to be better defined. Our aim was to investigate the bone effects of different vibration frequencies at constant g level. Vertical WBV was delivered at 0.7 g (peak acceleration) and 8, 52 or 90 Hz sinusoidal vibration to mature male rats 10 min daily for 5 days/week for 4 weeks. Peak accelerations measured by skin or bone-mounted accelerometers at L2 vertebral and tibia crest levels revealed similar values between adjacent skin and bone sites. Local accelerations were greater at 8 Hz compared with 52 and 90 Hz and were greater in vertebra than tibia for all the frequencies tested. At 52 Hz, bone responses were mainly seen in L2 vertebral body and were characterized by trabecular reorganization and stimulated mineral apposition rate (MAR) without any bone volume alteration. At 90 Hz, axial and appendicular skeletons were affected as were the cortical and trabecular compartments. Cortical thickness increased in femur diaphysis (17%) along with decreased porosity; trabecular bone volume increased at distal femur metaphysis (23%) and even more at L2 vertebral body (32%), along with decreased SMI and increased trabecular connectivity. Trabecular thickness increased at the tibia proximal metaphysis. Bone cellular activities indicated a greater bone formation rate, which was more pronounced at vertebra (300%) than at long bone (33%). Active bone resorption surfaces were unaffected. At 8 Hz, however, hyperosteoidosis with reduced MAR along with increased resorption surfaces occurred in the tibia; hyperosteoidosis and trend towards decreased MAR was also seen in L2 vertebra. Trabecular bone mineral density was decreased at femur and tibia. Thus the most favorable regimen is 90 Hz, while deleterious effects were seen at 8 Hz. We concluded that the skeleton is frequency-scalable, thus highlighting the importance of WBV regimen conditions and suggesting that cautions are required for frequencies less than 10 Hz, at least in rats. PMID:23545229

Pasqualini, Marion; Lavet, Cédric; Elbadaoui, Mohamed; Vanden-Bossche, Arnaud; Laroche, Norbert; Gnyubkin, Vasily; Vico, Laurence

2013-07-01

26

Silicon alleviates deleterious effects of high salinity on the halophytic grass Spartina densiflora.  

PubMed

The non-essential element silicon is known to improve plant fitness by alleviating the effects of biotic and abiotic stresses, particularly in crops. However, its possible role in the exceptional tolerance of halophytes to salinity has not been investigated. This study reports the effect of Si supply on the salinity tolerance of the halophytic grass Spartina densiflora; plants were treated with NaCl (0-680 mM), with or without silicon addition of 500 ?M, in a glasshouse experiment. Plant responses were examined using growth analysis, combined with measurements of gas exchange, chlorophyll fluorescence and photosynthetic pigment concentrations. In addition, tissue concentrations of aluminium, calcium, copper, iron, potassium, magnesium, sodium, phosphorus and silicon were determined. Although high salinity decreased growth, this effect was alleviated by treatment with Si. Improved growth was associated with higher net photosynthetic rate (A), and greater water-use efficiency (WUE). Enhanced A at high salinity could be explained by beneficial effects of Si on the photochemical apparatus, and on chlorophyll concentrations. Ameliorative effects of Si were correlated with reduced sodium uptake, which was unrelated to a reduction in the transpiration rate, since Si-supplemented plants had higher stomatal conductances (G(s)). These plants also had higher tissue concentrations of essential nutrients, suggesting that Si had a positive effect on the mineral nutrient balance in salt-stressed plants. Si appears to play a significant role in salinity tolerance even in a halophyte, which has other, specific salt-tolerance mechanisms, through diverse protective effects on the photosynthetic apparatus, water-use efficiency and mineral nutrient balance. PMID:23257076

Mateos-Naranjo, Enrique; Andrades-Moreno, Luis; Davy, Anthony J

2013-02-01

27

Nonmicrowave health and ecological effects: Overview  

NASA Technical Reports Server (NTRS)

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

White, M. R.

1980-01-01

28

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

PubMed Central

SUMMARY 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 lifespan and healthspan of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on CR regimens of chronic CR (CCR) or intermittent fasting (IF) had increased lifespan compared to mothers fed ad libitum (AL). With increasing maternal age, lifespan and fecundity of female offspring of AL fed mothers decreased significantly and lifespan of male offspring was unchanged, while body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean lifespan of AL fed female offspring but not male offspring and increasing the fecundity of AL fed female offspring compared to 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, while 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 healthspan and lifespan.

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

2014-01-01

29

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

PubMed

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

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

2014-08-01

30

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

ERIC Educational Resources Information Center

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

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

2005-01-01

31

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

ERIC Educational Resources Information Center

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

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

2000-01-01

32

Genistein Induces Deleterious Effects during Its Acute Exposure in Swiss Mice  

PubMed Central

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

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

2014-01-01

33

Imatinib has deleterious effects on differentiating spermatogonia while sparing spermatogonial stem cell self renewal  

PubMed Central

Imatinib mesylate is among a growing number of effective cancer drugs that provide molecularly targeted therapy; however, imatinib causes reproductive defects in rodents. The availability of an in vitro system for screening the effect of drugs on spermatogenesis would be beneficial. The imatinib targets, KIT and platelet-derived growth factor receptor beta (PDGFRB), were shown here to be expressed in “germline stem” (GS) cell cultures that contain spermatogonia, including spermatogonial stem cells (SSCs). GS cell cultures were utilized to determine whether imatinib affects SSC self renewal or differentiation. GS cells grown in imatinib retained self renewal based on multiple assays, including transplantation. However, growth in imatinib led to decreased numbers of differentiated spermatogonia and reduced culture growth consistent with the known requirement for KIT in survival and proliferation of spermatogonia. These results build upon the in vivo studies and support the possibility of utilizing GS cell cultures for preclinical drug tests.

Heim, Crystal; Minniear, Kayla; Dann, Christina Tenenhaus

2011-01-01

34

Erythropoietin Promotes Deleterious Cardiovascular Effects and Mortality Risk in a Rat Model of Chronic Sports Doping  

Microsoft Academic Search

Athletes who abuse recombinant human erythropoietin (rhEPO) consider only the benefit to performance and usually ignore the\\u000a potential short and long-term liabilities. Elevated haematocrit and dehydratation associated with intense exercise may reveal\\u000a undetected cardiovascular risk, but the mechanisms underlying it remain to be fully explained. This study aimed to evaluate\\u000a the cardiovascular effects of rhEPO in rats under chronic aerobic

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

2009-01-01

35

Deleterious Effect of Cirrhosis on Outcomes After Motor Vehicle Crashes Using the Nationwide Inpatient Sample  

Microsoft Academic Search

OBJECTIVES:Alcohol abuse and minimal hepatic encephalopathy may predispose cirrhotics to a higher motor vehicle crash (MVC) rate. Cirrhotics have poor post-trauma outcomes on small-scale studies. The aim was to examine the effect of cirrhosis on mortality, charges, and length of stay (LOS) after MVCs using the Nationwide Inpatient Sample (NIS) 2004.METHODS:NIS 2004 was queried for cirrhotics with MVC (C-MVC), cirrhotics

Jasmohan S. Bajaj; Ashwin N. Ananthakrishnan; Emily L. McGinley; Raymond G. Hoffmann; Karen J. Brasel

2008-01-01

36

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

PubMed

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

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

2014-05-01

37

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

PubMed

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

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

2009-07-01

38

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

PubMed

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

Kheirandish, R; Askari, N; Babaei, H

2014-03-01

39

Potential deleterious haemodynamic effects of glyceryl trinitrate on myocardial ischaemia in man.  

PubMed Central

The potential adverse effects of glyceryl trinitrate on myocardial ischaemia were studied using low and high dose infusions in 10 patients with coronary heart disease. Cardiac venous flow was measured by the thermodilution technique and blood was sampled for metabolic studies. Angina pectoris was provoked by atrial pacing before drug infusion and the same heart rate was regained with low and high doses of glyceryl trinitrate. Both doses reduced myocardial ischaemia equally. The low dose of glyceryl trinitrate reduced mean systolic aortic pressure from 145(23) to 128(23) mm Hg and the high dose further to 103(9) mm Hg. Myocardial oxygen uptake decreased owing to a combined reduction in preload and afterload with the low dose and was substantially more reduced with the high dose owing to a further afterload reduction. Transmural perfusion gradient did not change with the low dose of glyceryl trinitrate but fell significantly with the high dose. This fall in myocardial perfusion probably accounts for the lack of further reduction in ischaemia with the high dose. Thus the adverse effects of glyceryl trinitrate infusion are small and do not increase myocardial ischaemia.

Ihlen, H; Myhre, E; Smith, H J

1984-01-01

40

[Deleterious cardiac effects of serotonin in myocardial ischemia: role of naftidrofuryl].  

PubMed

It is now accepted that serotonin can either initiate or aggravate myocardial ischaemia through a vasoconstrictor action and platelet activation. It is therefore possible that substances likely to neutralize the effects of serotonin could be used, without any danger, in humans with ischaemic heart disease. This type of action may therefore be exerted by 5-HT2 antagonists, such as naftidrofuryl. A recent double-blind clinical study has in fact shown that administration of naftidrofuryl versus placebo leads to better exercise tolerance, with an increase in the maximum level and delay in ST segment shift (increase in the threshold of onset of ischaemia). The purpose of this study was therefore to evaluate, in an animal model (pig) of acute myocardial ischaemia (occlusion of the proximal section of the left anterior descending coronary artery), the action of serotonin, naftidrofuryl and a combination of both substances on the following parameters: 1) electrophysiological (sinus heart rate, ST segment shift, T-wave amplitude, duration of monophasic action potentials, intraventricular conduction time); 2) haemodynamic (systolic, diastolic and mean blood pressure, first derivative of rate of increase of left ventricular pressure with time: LV dP/dt max); and 3) biochemical (malonedialdehyde concentration as an index, cell peroxidation index, creatine phosphate and adenosine triphosphate). It was found that co-infusion of serotonin aggravated the myocardial ischemia and that naftidrofuryl exerted beneficial effects on the serotonin-mediated aggravation of myocardial ischaemia. PMID:12555598

Kioueh, I; Mosnier, M; Bui-Xuan, B; Frassati, D; Descotes, J; Timour, Q

2001-06-01

41

Normal physical activity obliterates the deleterious effects of a high-caloric intake.  

PubMed

A high-caloric intake combined with a sedentary lifestyle is an important player in the development of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine if the level of physical activity has impact on the metabolic effects of a high-caloric (+2,000 kcal/day) intake. Therefore, healthy individuals on a high-caloric intake were randomized to either 10,000 or 1,500 steps/day for 14 days. Step number, total energy expenditure, dietary records, neuropsychological tests, maximal oxygen uptake (Vo2max), whole body dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) scans, continuous glucose monitoring (CGM), and oral glucose tolerance tests (OGTT) with stable isotopes were performed before and after the intervention. Both study groups gained the same amount of body weight. However, the inactive group accumulated significantly more visceral fat compared with the active group. Following the 2-wk period, the inactive group also experienced a poorer glycemic control, increased endogenous glucose production, decreased hepatic insulin extraction, increased baseline plasma levels of total cholesterol and LDL, and a decreased cognitive function with regard to capacity of attention. In conclusion, we find evidence to support that habitual physical activity may prevent pathophysiological symptoms associated with diet-induced obesity. PMID:24201706

Krogh-Madsen, Rikke; Pedersen, Maria; Solomon, Thomas P J; Knudsen, Sine Haugaard; Hansen, Louise Seier; Karstoft, Kristian; Lehrskov-Schmidt, Louise; Pedersen, Karin Kaereby; Thomsen, Carsten; Holst, Jens Juul; Pedersen, Bente K

2014-02-01

42

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

PubMed Central

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

Buthet, Lara Romina; Maciel, Maria Eugenia; Quintans, Leandro Nestor; Rodriguez de Castro, Carmen; Costantini, Martin Hernan; Castro, Jose Alberto

2013-01-01

43

Deleterious effects of prolonged electrical excitation of striate cortex in macaques.  

PubMed

Macaques were trained to respond to electrical excitation applied through electrodes permanently implanted within or upon striate cortex. Threshold current for the animal to detect this stimulation was highly consistent from day to day and, in the absence of tissue encapsulation of the electrodes or deliberately inflicted damage, remained stable indefinitely, 38 months in the longest case so far. Stimulating continuously for 1-8h, however, produces an elevation of threshold, which may be permanent or temporary, depending upon a variety of conditions. A major cause of such injury is the hydrolysis commonly occurring consequent to passage of low-level currents between solutions and metal electrodes. Even when the hydrolytic reaction is eliminated by restricting the level of electrode polarization or by using capacitative stimulation with tantalum pentoxide electrodes, a rise in threshold often still occurs with protracted stimulation. With proper control in some instances, however, effective stimulation at 2-10 times the threshold level could be maintained indefinitely without apparent injury, e.g. in a blind monkey having a threshold of 290 muA that could respond immediately to an 80-muA diminution in 580-muA, 0.2-msec stimulus pulses which had been applied steadily for 1 h at 50 Hz. PMID:402170

Bartlett, J R; Doty, R W; Lee, B B; Negrão, N; Overman, W H

1977-02-01

44

Reversing the deleterious effects of ?2-antiplasmin on tissue plasminogen activator therapy improves outcomes in experimental ischemic stroke.  

PubMed

High blood levels of ?2-antiplasmin have been associated with failed tissue plasminogen activator (TPA) therapy for ischemic stroke. Yet, other data suggests that ?2-antiplasmin may be protective in stroke, because it defends against bleeding and excitotoxicity. To address this paradox, we examined the effects of high ?2-antiplasmin levels and ?2-antiplasmin inactivation in mice treated with TPA 0.5-2.5h after middle cerebral artery (MCA) thromboembolism. Brain infarction, swelling, hemorrhage, blood brain barrier breakdown and neuronal apoptosis were measured by a blinded observer. Thrombus dissolution was determined by gamma counting. During TPA treatment, high ?2-antiplasmin blood levels increased brain infarction (2.2-fold) and swelling (3.7-fold), but decreased MCA thrombus dissolution. Conversely, ?2-antiplasmin inactivation during TPA treatment reduced brain infarction, hemorrhage and swelling, but increased MCA thrombus dissolution. Inactivation of ?2-antiplasmin during TPA treatment reduced neuronal apoptosis and blood brain barrier breakdown. Inactivation of ?2-antiplasmin also reduced short-term mortality. Taken together these data show that ?2-antiplasmin opposes the effects of TPA therapy and contributes to enhanced brain injury after experimental thromboembolic stroke. Conversely, ?2-antiplasmin inactivation during TPA treatment improves thrombus dissolution and reduces brain infarction, swelling and hemorrhage. Consistent with clinical observations, these data suggest that ?2-antiplasmin exerts deleterious effects that reduce the efficacy and safety of TPA therapy for ischemic stroke. PMID:24556477

Houng, Aiilyan K; Wang, Dong; Reed, Guy L

2014-05-01

45

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

NASA Astrophysics Data System (ADS)

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.

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

2001-06-01

46

Activators of the glutamate-dependent acid resistance system alleviate deleterious effects of YidC depletion in Escherichia coli.  

PubMed

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

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

2011-03-01

47

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

PubMed Central

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

Soriano, Sirena; Botella, Jose A.; Schneuwly, Stephan; Martinez-Sebastian, Maria J.; Molto, Maria D.

2011-01-01

48

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

PubMed

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

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

2011-02-01

49

Distinct deleterious effects of cyclosporine and tacrolimus and combined tacrolimus-sirolimus on endothelial cells: protective effect of defibrotide.  

PubMed

Endothelial dysfunction seems to be a key factor in the development of several complications observed early after hematopoietic stem cell transplantation (HSCT). The conditioning regimen and many other factors associated with the procedure are responsible for this endothelial damage. The effects of immunosuppressive agents on endothelial function have not been explored in detail. We evaluated the effects of 3 drugs commonly used in HSCT: 2 calcineurin inhibitors, cyclosporine A (CSA) and tacrolimus (TAC), and an inhibitor of mTOR, sirolimus (SIR). We also evaluated the effect of the combination of TAC and SIR (TAC+SIR), which is used increasingly in clinical practice. Microvascular endothelial cells (HMEC-1) were exposed to these drugs to evaluate changes in (1) intercellular adhesion molecule (ICAM)-1 expression on the cell surface, assessed by immunofluorescence labeling and expressed as the mean gray value (MGV); (2) reactivity of the extracellular matrix (ECM) toward platelets, upon exposure of the ECM to circulating blood; and (3) whole-blood clot formation, assessed by thromboelastometry. Studies were conducted in the absence and presence of defibrotide (DF) to assess its possible protective effect. The exposure of HMEC-1 to CSA and TAC+SIR significantly increased the expression of ICAM-1 (157.5 ± 11.6 and 153.4 ± 9.5 MGV, respectively, versus 105.7 ± 6.5 MGV in controls [both P < .05]). TAC applied alone increased ICAM-1 slightly (120.3 ± 8.2 MGV), and SIR had no effect (108.9 ± 7.4 MGV). ECM reactivity increased significantly only in response to CSA (surface covered by platelets of 41.2% ± 5.4% versus 30.1% ± 2.0%, P < .05). DF attenuated all these changes. No significant changes in the viscoelastic properties of clot formation were observed in any condition with blood samples incubated in vitro. In conclusion, CSA and TAC+SIR had a proinflammatory effect, but only CSA exhibited an additional prothrombotic effect. Interestingly, DF exerted clear protective anti-inflammatory and antithrombotic effects on the endothelium. PMID:23845694

Carmona, Alba; Díaz-Ricart, Maribel; Palomo, Marta; Molina, Patricia; Pino, Marc; Rovira, Montserrat; Escolar, Ginés; Carreras, Enric

2013-10-01

50

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

PubMed

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

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

2007-06-01

51

Ecological Correlates of Effective Foster Care  

ERIC Educational Resources Information Center

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

Henderson, Daphne; Scannapieco, Maria

2006-01-01

52

OVERVIEW OF CLIMATE INFORMATION NEEDS FOR ECOLOGICAL EFFECTS MODELS  

EPA Science Inventory

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

53

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...

54

Ecological effects of particulate matter  

Microsoft Academic Search

Atmospheric particulate matter (PM) is a heterogeneous material. Though regulated as un-speciated mass, it exerts most effects on vegetation and ecosystems by virtue of the mass loading of its chemical constituents. As this varies temporally and spatially, prediction of regional impacts remains difficult. Deposition of PM to vegetated surfaces depends on the size distribution of the particles and, to a

D. A Grantz; J. H. B Garner; D. W Johnson

2003-01-01

55

Ecological effects of particulate matter.  

PubMed

Atmospheric particulate matter (PM) is a heterogeneous material. Though regulated as un-speciated mass, it exerts most effects on vegetation and ecosystems by virtue of the mass loading of its chemical constituents. As this varies temporally and spatially, prediction of regional impacts remains difficult. Deposition of PM to vegetated surfaces depends on the size distribution of the particles and, to a lesser extent, on the chemistry. However, chemical loading of an ecosystem may be determined by the size distribution as different constituents dominate different size fractions. Coating with dust may cause abrasion and radiative heating, and may reduce the photosynthetically active photon flux reaching the photosynthetic tissues. Acidic and alkaline materials may cause leaf surface injury while other materials may be taken up across the cuticle. A more likely route for metabolic uptake and impact on vegetation and ecosystems is through the rhizosphere. PM deposited directly to the soil can influence nutrient cycling, especially that of nitrogen, through its effects on the rhizosphere bacteria and fungi. Alkaline cation and aluminum availability are dependent upon the pH of the soil that may be altered dramatically by deposition of various classes of PM. A regional effect of PM on ecosystems is linked to climate change. Increased PM may reduce radiation interception by plant canopies and may reduce precipitation through a variety of physical effects. At the present time, evidence does not support large regional threats due to un-speciated PM, though site-specific and constituent-specific effects can be readily identified. Interactions of PM with other pollutants and with components of climate change remain important areas of research in assessment of challenges to ecosystem stability. PMID:12676209

Grantz, D A; Garner, J H B; Johnson, D W

2003-06-01

56

Marine reserves: Fish life history and ecological traits matter  

Microsoft Academic Search

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

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

57

Pyrrolidine Dithiocarbamate Prevents Deleterious Effects of Remote Ischemia\\/Reperfusion Injury on Healing of Colonic Anastomoses in Rats  

Microsoft Academic Search

Background  Pyrrolidine dithiocarbamate (PDTC) is a low-molecular-weight thiol antioxidant and potent inhibitor of nuclear factor-?B (NF-?B)\\u000a activation. It has been shown to attenuate local harmful effects of ischemia\\/reperfusion (I\\/R) injury in many organs. In recent\\u000a animal studies, a delaying effect of remote organ I\\/R injury on the healing of colonic anastomoses has been demonstrated.\\u000a In this study we investigated whether PDTC

Zafer Teke; Faruk Onder Aytekin; Burhan Kabay; Cigdem Yenisey; Cagatay Aydin; Koray Tekin; Mustafa Sacar; Akin Ozden

2007-01-01

58

Cascading ecological effects of eliminating fishery discards  

PubMed Central

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.

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

2014-01-01

59

Cascading ecological effects of eliminating fishery discards.  

PubMed

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

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

2014-01-01

60

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

PubMed Central

Self-regulation depletion (SRD), or ego-depletion, refers to decrements in self-regulation performance immediately following a different self-regulation-demanding activity. There are now over a hundred studies reporting SRD across a broad range of tasks and conditions. However, most studies have used young student samples. Because prefrontal brain regions thought to subserve self-regulation do not fully mature until 25 years of age, it is possible that SRD effects are confined to younger populations and are attenuated or disappear in older samples. We investigated this using the Stroop color task as an SRD induction and an autobiographical memory task as the outcome measure. We found that younger participants (<25 years) were susceptible to depletion effects, but found no support for such effects in an older group (40–65 years). This suggests that the widely-reported phenomenon of SRD has important developmental boundary conditions casting doubt on claims that it represents a general feature of human cognition.

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

2011-01-01

61

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

PubMed

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

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

62

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

PubMed Central

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.

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

2014-01-01

63

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

PubMed Central

Suppression of natural killer (NK) cell activity is common following stress, has been reported to predict malignant recurrence in cancer patients, and was shown to underlie metastatic dissemination in animal models. We have previously reported that catecholamines play a major role in NK cell suppression, particularly in the context of physiological stress and surgery. In the current study using F344 rats, we examined the prophylactic use of different regimens of type-C CpG oligodeoxynucleotides (CpG-C ODN) on NK activity and metastatic dissemination in the context of pharmacological stress (using metaproterenol for ?-adrenoceptor stimulation). Our results indicated that the beneficial effects of CpG-C ODN were more profound under pharmacological stress than under baseline conditions. A bolus of CpG-C ODN (330?g/kg, i.p.) 24 hrs prior to metaproterenol-challenge was most effective at reducing lung tumor retention of an experimental syngeneic mammary adenocarcinoma (MADB106), while having no observable side effects. Depletion of NK cells revealed their key role in improving baseline levels of resistance to metastatic dissemination following CpG-C ODN administration. When NK cell cytotoxicity was assessed in the circulation and the marginating-pulmonary immune compartments we found that CpG-C ODN protected individual NK cells from metaproterenol-induced suppression in both compartments. Moreover, in the critical marginating-pulmonary compartment, CpG-C ODN also elevated baseline cytotoxicity per NK cell against MADB106 tumor cells, and increased NK cell numbers in non-stressed rats. Overall, prophylactic CpG-C ODN treatment can improve immunocompetence and potentially reduce metastatic dissemination, especially in clinical settings characterized by enhanced sympathetic stress responses.

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

2009-01-01

64

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

PubMed

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

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

2009-04-01

65

Porcine oviduct sperm binding glycoprotein and its deleterious effect on sperm: a mechanism for negative selection of sperm?  

PubMed

In their journey through the oviduct some subpopulations of sperm are preserved in a reservoir, while others are negatively selected. Sperm binding glycoprotein (SBG) is a pig oviductal epithelial cell glycoprotein that produces, under capacitating conditions, acrosome alteration, p97 tyrosine-phosphorylation and reduction of the motility of sperm. In this paper, we show that SBG is accessible at the extracellular surface of the oviductal epithelial cells, supporting a sperm interaction biological role in situ. We analyze the possible dependence of the tyrosine-phosphorylation of p97 on the PKA mechanism, finding that apparently it is not PKA dependent. Also, after SBG treatment the phosphorylated proteins locate mainly at the detached periacrosomal region and at the tail of sperm; the latter may be related to SBG's motility reduction effect. The study of the time course effect of SBG on sperm as detected by chlortetracycline (CTC) staining and of its binding to sperm by immunodetection in conjunction with CTC, shows results in agreement with the hypothesis that this glycoprotein is involved in the alteration of acrosomes in a specific sperm subpopulation. The results suggest that SBG may be part of a mechanism for negative selection of sperm. PMID:22446595

Teijeiro, Juan M; Dapino, Dora G; Marini, Patricia E

2011-01-01

66

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

NASA Technical Reports Server (NTRS)

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.

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

1992-01-01

67

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

EPA Science Inventory

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

68

Phthalate-Induced Liver Protection against Deleterious Effects of the Th1 Response: A Potentially Serious Health Hazard  

PubMed Central

Infection with Mycobacterium tuberculosis (TB) induces pulmonary immunopathology mediated by classical Th1 type of acquired immunity with hepatic involvement in up to 80% of disseminated cases. Since PPAR agonists cause immune responses characterized by a decrease in the secretion of Th1 cytokines, we investigated the impact of activating these receptors on hepatic pathology associated with a well-characterized model of Th1-type pulmonary response. Male Fischer 344 rats were either maintained on a drug-free diet (groups I and II), or a diet containing diethylhexylphthalate (DEHP), a compound transformed in vivo to metabolites known to activate PPARs, for 21 days (groups III and IV). Subsequently, animals were primed with Mycobacterium bovis purified protein derivative (PPD) in a Complete Freund's Adjuvant. Fifteen days later, animals in groups II and IV were challenged with Sepharose 4B beads covalently coupled with PPD, while animals in groups I and III received blank Sepharose beads. Animals with Th1 response (group II) showed a marked structural disruption in the hepatic lobule. Remarkably, these alterations were conspicuously absent in animals which received DEHP (group IV), despite noticeable accumulation of T cells in the periportal triads. Immunostaining and confocal microscopy revealed hepatic accumulation of IFN?+ Th1 and IL-4+ Th2 cells in animals from groups II and IV, respectively. Our data suggest a PPAR?-mediated suppression of the development of a Th1 immune response in the liver, resulting in hepatoprotective effect. However, potentially negative consequences of PPAR activation, such as decreased ability of the immune system to fight infection and interference with the efficacy of vaccines designed to evoke Th1 immune responses, remain to be investigated.

Badr, Mostafa Z.; Shnyra, Alexander; Zoubine, Mikhail; Norkin, Maxim; Herndon, Betty; Quinn, Tim; Miranda, Roberto N.; Cunningham, Michael L.; Molteni, Agostino

2007-01-01

69

Deleterious effects of reactive metabolites  

PubMed Central

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

2010-01-01

70

Deleterious background selection with recombination  

SciTech Connect

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

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

1995-12-01

71

Efficacy of a new ochratoxin-binding agent (OcraTox) to counteract the deleterious effects of ochratoxin A in laying hens.  

PubMed

An experiment was conducted to evaluate the efficacy of a new ochratoxin-binding agent (Ocra-Tox, 5 g/kg of feed) in offsetting the toxic effects of ochratoxin A (OTA, 2 mg/kg of feed) in laying hen diets. Performance, serum biochemistry, OTA residue in the liver and eggs, and egg quality parameters were evaluated. Twenty-eight Hisex Brown laying hens, 47 wk of age, were allocated to 1 of 4 experimental treatments for 3 wk: control, OTA (containing 2 mg of OTA/kg of feed), OcraTox (containing 5 g of OcraTox/kg of feed), and OTA + OcraTox (containing 2 mg of OTA and 5 g of OcraTox/kg of feed). Laying hens fed OcraTox showed results similar to the control hens (P > 0.05). The OTA diet significantly (P < 0.05) reduced daily feed consumption, egg mass production, and serum triglyceride concentrations, and increased the relative liver weight, the serum activity of alkaline phosphatase, and the serum concentration of uric acid as compared with the control diet. Addition of OcraTox to the contaminated diet alleviated (P < 0.05) the negative effects resulting from OTA, reaching values not significantly different from the control diet for most of the parameters except the relative weight of the liver. Birds fed the OTA treatment showed a greater content of OTA in the liver (15.1 microg/kg) than those fed the control diet (<0.05 microg/kg). Supplementing the contaminated diet with OcraTox (OTA + OcraTox) reduced the values to 12.0 microg/kg. Residues of OTA were not detected above our detection limit (0.05 microg/kg) in any of the analyzed eggs. In conclusion, our results indicated that addition of OcraTox can counteract the deleterious effects caused by OTA in laying hens. PMID:18931177

Denli, M; Blandon, J C; Guynot, M E; Salado, S; Perez, J F

2008-11-01

72

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

PubMed

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

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

2013-01-01

73

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

PubMed

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

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

2014-06-01

74

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

PubMed Central

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

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

2013-01-01

75

Developmental Expression of Musashi-1 and Musashi-2 RNA-Binding Proteins During Spermatogenesis: Analysis of the Deleterious Effects of Dysregulated Expression.  

PubMed

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

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

2014-01-01

76

Potential Ecological Effects of Contaminants in the Exposed Par Pond Sediments  

SciTech Connect

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

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

1996-08-01

77

Deleterious mutations and selection for sex in finite diploid populations.  

PubMed

In diploid populations, indirect benefits of sex may stem from segregation and recombination. Although it has been recognized that finite population size is an important component of selection for recombination, its effects on selection for segregation have been somewhat less studied. In this article, we develop analytical two- and three-locus models to study the effect of recurrent deleterious mutations on a modifier gene increasing sex, in a finite diploid population. The model also incorporates effects of mitotic recombination, causing loss of heterozygosity (LOH). Predictions are tested using multilocus simulations representing deleterious mutations occurring at a large number of loci. The model and simulations show that excess of heterozygosity generated by finite population size is an important component of selection for sex, favoring segregation when deleterious alleles are nearly additive to dominant. Furthermore, sex tends to break correlations in homozygosity among selected loci, which disfavors sex when deleterious alleles are either recessive or dominant. As a result, we find that it is difficult to maintain costly sex when deleterious alleles are recessive. LOH tends to favor sex when deleterious mutations are recessive, but the effect is relatively weak for rates of LOH corresponding to current estimates (of the order 10(-4)-10(-5)). PMID:20083613

Roze, Denis; Michod, Richard E

2010-04-01

78

Ecology: Nonlinearity and the Moran effect  

NASA Astrophysics Data System (ADS)

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

Blasius, Bernd; Stone, Lewi

2000-08-01

79

The sensory ecology of nonconsumptive predator effects.  

PubMed

Abstract Nonconsumptive effects (NCEs) have been shown to occur in numerous systems and are regarded as important mechanisms by which predation structures natural communities. Sensory ecology-that is, the processes governing the production, propagation, and masking of cues by ambient noise-provides insights into the strength of NCEs as functions of the environment and modes of information transfer. We discuss how properties of predators are used by prey to encode threat, how the environment affects cue propagation, and the role of single sensory processes versus multimodal sensory processes. We discuss why the present body of literature documents the potential for strong NCEs but does not allow us to easily determine how this potential is expressed in nature or what factors or environments produce strong versus weak NCEs. Many of these difficulties stem from a body of literature in which certain sensory environments and modalities may be disproportionately represented and in which experimental methodologies are designed to show the existence of NCEs. We present a general framework for examining NCEs to identify the factors controlling the number of prey that respond to predator cues and discuss how the properties of predators, prey, and the environment may determine prey perceptive range and the duration and frequency of cue production. We suggest how understanding these relationships provides a schema for determining where, when, why, and how NCEs are important in producing direct and cascading effects in natural communities. PMID:25058276

Weissburg, Marc; Smee, Delbert L; Ferner, Matthew C

2014-08-01

80

Effective discharge analysis of ecological processes in streams  

USGS Publications Warehouse

[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.

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

2005-01-01

81

Indicators of Ecological Effects of Air Quality. Final Report.  

National Technical Information Service (NTIS)

Ecological indicators are needed to improve understanding and monitoring of the effects of air pollutants on ecosystems and to scientifically assess the effectiveness of air pollution control strategies. Traditionally, research and monitoring of air quali...

2009-01-01

82

Efficient purging of deleterious mutations in plants with haploid selfing.  

PubMed

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

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

2014-05-01

83

Efficient Purging of Deleterious Mutations in Plants with Haploid Selfing  

PubMed Central

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

Szovenyi, Peter; Devos, Nicolas; Weston, David J.; Yang, Xiaohan; Hock, Zsofia; Shaw, Jonathan A.; Shimizu, Kentaro K.; McDaniel, Stuart F.; Wagner, Andreas

2014-01-01

84

TOWARD MODELING THE ECOLOGICAL EFFECTS OF CHEMICALS ACTING JOINTLY  

EPA Science Inventory

A physical basis is sought for modeling the ecological effects of neutral, hydrophobic chemicals acting jointly. It is assumed that these chemicals cross biological membranes passively, driven by gradients in chemical potential, and are distributed among chemical phases (types of...

85

State of the Coastal Environment: Ecological Effects of Fishing.  

National Technical Information Service (NTIS)

This essay is a 'pressure' topic, intended to document the ecological effects that fishing can have on living marine resources and their environment. Fishing provides many benefits to society, including food, employment, business opportunities, and recrea...

L. Lauck M. Coyne P. J. Auster S. K. Brown

1998-01-01

86

EVOLUTIONARY AND ECOLOGICAL EFFECTS OF MULTIGENERATIONAL EXPOSURES TO ANTHROPOGENIC STRESSORS  

EPA Science Inventory

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

87

Ecological Effects of the War in Vietnam  

ERIC Educational Resources Information Center

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

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

1970-01-01

88

Deleterious Mutations and the Evolution of Sex  

Microsoft Academic Search

It has been suggested that sexual reproduction is maintained because it reduces the load imposed by recurrent deleterious mutations. If rates of deleterious mutation per diploid genome per generation (U) exceed 1, and mutations interact synergistically, then sexuals can overcome their inherent twofold disadvantage. We have tested this hypothesis by estimating genomic point mutation rates for protein-coding genes in a

Peter D. Keightley; Adam Eyre-Walker

2000-01-01

89

Ecological and Evolutionary Effects of Stickleback on Community Structure  

PubMed Central

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.

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

2013-01-01

90

[Effect of ecological factors on citrus fruit quality].  

PubMed

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

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

2004-08-01

91

N-CARBAMYLGLUTAMATE ENHANCEMENT OF UREAGENESIS LEADS TO DISCOVERY OF A NOVEL DELETERIOUS MUTATION IN A NEWLY DEFINED ENHANCER OF THE NAGS GENE AND TO EFFECTIVE THERAPY  

PubMed Central

NAGS catalyzes the conversion of glutamate and acetyl-CoA to N-acetylglutamate (NAG) the essential allosteric activator of carbamyl phosphate synthetase I, the first urea cycle enzyme in mammals. A 17-year-old female with recurrent hyperammonemia attacks, the cause of which remained undiagnosed for 8 years in spite of multiple molecular and biochemical investigations, showed markedly enhanced ureagenesis (measured by isotope incorporation) in response to N-carbamylglutamate (NCG). This led to sequencing of the regulatory regions of the NAG synthase (NAGS) gene and identification of a deleterious single-base substitution in the upstream enhancer. The homozygous mutation (-3063C>A), affecting a highly conserved nucleotide within the Hepatic Nuclear Factor 1 (HNF-1) binding site, was not found in SNP databases and in a screen of 1086 alleles from a diverse population. Functional assays demonstrated that this mutation decreases transcription and binding of HNF-1 to the NAGS gene, while a consensus HNF-1 binding sequence enhances binding to HNF-1 and increases transcription. Oral daily NCG therapy appears to have restored ureagenesis in this patient, normalizing her biochemical markers, and allowing discontinuation of alternate pathway therapy and normalization of her diet with no recurrence of hyperammonemia.

Heibel, Sandra K.; Mew, Nicholas Ah; Caldovic, Ljubica; Daikhin, Yevgeny; Yudkoff, Marc; Tuchman, Mendel

2014-01-01

92

Nature of deleterious mutation load in Drosophila.  

PubMed

Much population genetics and evolution theory depends on knowledge of genomic mutation rates and distributions of mutation effects for fitness, but most information comes from a few mutation accumulation experiments in Drosophila in which replicated chromosomes are sheltered from natural selection by a balancer chromosome. I show here that data from these experiments imply the existence of a large class of minor viability mutations with approximately equivalent effects. However, analysis of the distribution of viabilities of chromosomes exposed to EMS mutagenesis reveals a qualitatively different distribution of effects lacking such a minor effects class. A possible explanation for this difference is that transposable element insertions, a common class of spontaneous mutation event in Drosophila frequently generate minor viability effects. This explanation would imply that current estimates of deleterious mutation rates are not generally applicable in evolutionary models, as transposition rates vary widely. Alternatively, much of the apparent decline in viability under spontaneous mutation accumulation could have been nonmutational, perhaps due to selective improvement of balancer chromosomes. This explanation accords well with the data and implies a spontaneous mutation rate for viability two orders of magnitude lower than previously assumed, with most mutation load attributable to major effects. PMID:8978082

Keightley, P D

1996-12-01

93

Protective Effects of EPA and Deleterious Effects of DHA on eNOS Activity in Ea hy 926 Cultured with Lysophosphatidylcholine  

Microsoft Academic Search

Oxidized low density lipoprotein (Ox-LDL) is a well-established risk factor in atherosclerosis and lysophosphatidylcholine\\u000a (LysoPtdCho) is considered to be one of the major atherogenic component of Ox-LDL. The purpose of this work was to investigate\\u000a the effects of two membrane n-3 long chain polyunsaturated fatty acids (n-3 PUFAs), EPA (eicosapentaenoic acid) and DHA (docosahexaenoic\\u000a acid) compared to n-6 PUFA, ARA

Sylviane Tardivel; Aurélie Gousset-Dupont; Véronique Robert; Marie-Luce Pourci; Alain Grynberg; Bernard Lacour

2009-01-01

94

AQUATOX: Modeling environmental fate and ecological effects in aquatic ecosystems  

Microsoft Academic Search

AQUATOX combines aquatic ecosystem, chemical fate, and ecotoxicological constructs to obtain a truly integrative fate and effects model. It is a general, mechanistic ecological risk assessment model intended to be used to evaluate past, present, and future direct and indirect effects from various stressors including nutrients, organic wastes, sediments, toxic organic chemicals, flow, and temperature in aquatic ecosystems. The model

Richard A. Park; Jonathan S. Clough; Marjorie Coombs Wellman

2008-01-01

95

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

PubMed

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

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

2014-06-13

96

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...

97

Effective discharge analysis of ecological processes in streams  

Microsoft Academic Search

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

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

2005-01-01

98

Effects of Fisheries on Seabird Community Ecology  

Microsoft Academic Search

Significant depletions of marine fish populations due to overfishing are becoming more and more common. Such depletions have serious consequences not only for the fished species, but also for those organisms that depend on them for food. For seabirds, in particular, the effects of fisheries can be felt via a number of pathways. However, few studies have considered those effects

Eric L. Wagner; P. Dee Boersma

2011-01-01

99

Evidence for a slightly deleterious effect of intron polymorphisms at the EF1? gene in the deep-sea hydrothermal vent bivalve Bathymodiolus  

Microsoft Academic Search

A multilocus analysis was initiated in order to infer the general effect of demography and the indirect effect of positive selection on some chromosome segments in Bathymodiolus. Mussels of the genus Bathymodiolus inhabit the very hostile, fragmented and variable environment of deep-sea hydrothermal vents which is thought to cause recurrent population bottlenecks via extinction\\/colonisation processes and adaptation to new environmental

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

2007-01-01

100

Evolutionary invasion and escape in the presence of deleterious mutations.  

PubMed

Replicators such as parasites invading a new host species, species invading a new ecological niche, or cancer cells invading a new tissue often must mutate to adapt to a new environment. It is often argued that a higher mutation rate will favor evolutionary invasion and escape from extinction. However, most mutations are deleterious, and even lethal. We study the probability that the lineage will survive and invade successfully as a function of the mutation rate when both the initial strain and an adaptive mutant strain are threatened by lethal mutations. We show that mutations are beneficial, i.e. a non-zero mutation rate increases survival compared to the limit of no mutations, if in the no-mutation limit the survival probability of the initial strain is smaller than the average survival probability of the strains which are one mutation away. The mutation rate that maximizes survival depends on the characteristics of both the initial strain and the adaptive mutant, but if one strain is closer to the threshold governing survival then its properties will have greater influence. These conclusions are robust for more realistic or mechanistic depictions of the fitness landscapes such as a more detailed viral life history, or non-lethal deleterious mutations. PMID:23874532

Loverdo, Claude; Lloyd-Smith, James O

2013-01-01

101

Short-Term Effect of Diuron on Catfish Pond Ecology  

Microsoft Academic Search

We examined the effects of diuron treatment on catfish pond ecology under commercial culture conditions. Nine weekly treatments of diuron (0.01 mg\\/L) were applied to eight 0.4-ha experimental ponds; seven ponds served as controls. Water and fish samples were collected from all ponds each week for chemical and biological analysis. Data on mechanical aeration (hours of supplemental aeration required by

Paul V. Zimba; Craig S. Tucker; Charles C. Mischke; Casey C. Grimm

2002-01-01

102

Experiments on the role of deleterious mutations as stepping stones in adaptive evolution  

PubMed Central

Many evolutionary studies assume that deleterious mutations necessarily impede adaptive evolution. However, a later mutation that is conditionally beneficial may interact with a deleterious predecessor before it is eliminated, thereby providing access to adaptations that might otherwise be inaccessible. It is unknown whether such sign-epistatic recoveries are inconsequential events or an important factor in evolution, owing to the difficulty of monitoring the effects and fates of all mutations during experiments with biological organisms. Here, we used digital organisms to compare the extent of adaptive evolution in populations when deleterious mutations were disallowed with control populations in which such mutations were allowed. Significantly higher fitness levels were achieved over the long term in the control populations because some of the deleterious mutations served as stepping stones across otherwise impassable fitness valleys. As a consequence, initially deleterious mutations facilitated the evolution of complex, beneficial functions. We also examined the effects of disallowing neutral mutations, of varying the mutation rate, and of sexual recombination. Populations evolving without neutral mutations were able to leverage deleterious and compensatory mutation pairs to overcome, at least partially, the absence of neutral mutations. Substantially raising or lowering the mutation rate reduced or eliminated the long-term benefit of deleterious mutations, but introducing recombination did not. Our work demonstrates that deleterious mutations can play an important role in adaptive evolution under at least some conditions.

Covert, Arthur W.; Lenski, Richard E.; Wilke, Claus O.; Ofria, Charles

2013-01-01

103

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

PubMed

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

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

2014-03-01

104

Partial substitution of NO(3)(-) by NH(4)(+) fertilization increases ammonium assimilating enzyme activities and reduces the deleterious effects of salinity on the growth of barley.  

PubMed

Productivity of cereal crops is restricted in saline soils but may be improved by nitrogen nutrition. In this study, the effect of ionic nitrogen form on growth, mineral content, protein content and ammonium assimilation enzyme activities of barley (Hordeum vulgare cv. Alexis L.) irrigated with saline water, was determined. Leaf and tiller number as well as plant fresh and dry weights declined under salinity (120 mM NaCl). In non-saline conditions, growth parameters were increased by application of NH(4)(+)/NO(3)(-) (25:75) compared to NO(3)(-) alone. Under saline conditions, application of NH(4)(+)/NO(3)(-) led to a reduction of the detrimental effects of salt on growth. Differences in growth between the two nitrogen regimes were not due to differences in photosynthesis. The NH(4)(+)/NO(3)(-) regime led to an increase in total N in control and saline treatments, but did not cause a large decrease in plant Na(+) content under salinity. Activities of GS (EC 6.3.1.2), GOGAT (EC 1.4.1.14), PEPC (EC 4.1.1.31) and AAT (EC 2.6.1.1) increased with salinity in roots, whereas there was decreased activity of the alternative ammonium assimilation enzyme GDH (EC 1.4.1.2). The most striking effect of nitrogen regime was observed on GDH whose salinity-induced decrease in activity was reduced from 34% with NO(3)(-) alone to only 14% with the mixed regime. The results suggest that the detrimental effects of salinity can be reduced by partial substitution of NO(3)(-) with NH(4)(+) and that this is due to the lower energy cost of N assimilation with NH(4)(+) as opposed to NO(3)(-) nutrition. PMID:16545490

Kant, Surya; Kant, Pragya; Lips, Herman; Barak, Simon

2007-03-01

105

Ecological Effects of Nitrogen Deposition in the Western United States  

NSDL National Science Digital Library

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.

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

106

Deleterious effects of UV-B radiation on herbivorous spider mites: they can avoid it by remaining on lower leaf surfaces.  

PubMed

The herbivorous spider mite Tetranychus urticae usually remains on the lower leaf surfaces of its host plants. Although terrestrial animals are generally thought to be well protected from damage because of UV radiation, insect herbivory frequently increases when solar UV-B (280-315 nm) radiation is attenuated. As UV transmission through leaves is generally low because of the accumulation of compounds that act as selective sunscreens (e.g., phenolics), we hypothesized that T. urticae avoids solar UV-B radiation by staying on lower leaf surfaces. We examined whether artificial UV irradiation and solar UV affected the survival and reproduction of T. urticae and whether staying on lower leaf surfaces was beneficial to their performance under ambient UV radiation. We found that T. urticae was not well protected from UV-B radiation, because artificial UV-B irradiation strongly decreased survivorship and egg production. More importantly; compulsory solar UV irradiation treatments also had lethal effects on T. urticae, whereas the mites could avoid them if they remained on the lower leaf surfaces of their host plants. These results showed that access to habitats protected from sunlight, such as lower leaf surfaces, is likely essential for T. urticae survival under ambient UV-B radiation. The lethal effects of solar UV radiation may also affect the population dynamics of spider mites, and habitat (resource) limitation may increase the probability of interspecific interactions, such as competition and predation. In turn, the occurrence of these interactions in sheltered areas may be associated with observed increases in herbivory under conditions of solar UV-B-attenuation. PMID:19508803

Ohtsuka, Keiko; Osakabe, Masahiro M H

2009-06-01

107

Epstein-Barr virus protein EB2 stimulates cytoplasmic mRNA accumulation by counteracting the deleterious effects of SRp20 on viral mRNAs  

PubMed Central

The Epstein–Barr Virus (EBV) protein EB2 (also called Mta, SM and BMLF1), is an essential nuclear protein produced during the replicative cycle of EBV. EB2 is required for the efficient cytoplasmic accumulation of viral mRNAs derived from intronless genes. EB2 is an RNA-binding protein whose expression has been shown to influence RNA stability, splicing, nuclear export and translation. Using a yeast two-hybrid screen, we have identified three SR proteins, SF2/ASF, 9G8 and SRp20, as cellular partners of EB2. Then, by using siRNA to deplete cells of specific SR proteins, we found that SRp20 plays an essential role in the processing of several model mRNAs: the Renilla luciferase reporter mRNA, the human ?-globin cDNA transcript and two EBV late mRNAs. These four mRNAs were previously found to be highly dependent on EB2 for their efficient cytoplasmic accumulation. Here, we show that SRp20 depletion results in an increase in the accumulation of these mRNAs, which correlates with an absence of additive effect of EB2, suggesting that EB2 functions by antagonizing SRp20. Moreover, by using RNA-immunoprecipitation assays we found that EB2 enhances the association of SRp20 with the ?-globin transcript suggesting that EB2 acts by stabilizing SRp20’s labile interactions with the RNA.

Juillard, Franceline; Bazot, Quentin; Mure, Fabrice; Tafforeau, Lionel; Macri, Christophe; Rabourdin-Combe, Chantal; Lotteau, Vincent; Manet, Evelyne; Gruffat, Henri

2012-01-01

108

Phytoremediation potential of Maná-Cubiu (Solanum sessiliflorum Dunal) for the deleterious effects of methylmercury on the reproductive system of rats.  

PubMed

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

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

2014-01-01

109

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

PubMed Central

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.

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

2008-01-01

110

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

PubMed

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

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

2013-08-01

111

Calcium 'leak' through somatic L-type channels has multiple deleterious effects on regulated transmitter release from an invertebrate hair cell.  

PubMed

Using an identified synapse in the nervous system of the mollusc Hermissenda, the influence of somatic calcium accumulation on regulated synaptic transmission was investigated. Hair cells in Hermissenda project onto postsynaptic B photoreceptors where they mediate inhibitory postsynaptic potentials (IPSPs). Intracellular recordings in combination with bath perfusion of calcium channel modulators indicated that L-type channels were present on the hair cell soma but not on the terminal branches. In contrast, P/Q and an unidentified channel type (similar to N-type channels) contributed additively to transmitter release from the hair cell. Antibodies raised against rat brain channel proteins detected L- (alpha1(C)) and P/Q-type (alpha1(A)) channels in lysates of the Hermissenda nervous system, indicating a homology between the Hermissenda channels and their mammalian counterparts. To mimic somatic calcium channel 'leak', hair cells were exposed to the L-type channel agonist +/-BAY K 8644. Exposure to +/-BAY K 8644 resulted in a rapid (<2 min) increase (40%) in the amplitude of the spike after-hyperpolarization in the hair cell, and was associated with a reduction in evoked firing frequency. This reduction in rate of discharge induced a proportional decrease in the amplitude of compound IPSPs recorded in the postsynaptic B photoreceptors. From Fura-2 emissions we determined that +/-BAY K 8644 induced a rapid (<2 min) and persistent increase (70%) in somatic calcium concentration, followed by a slower elevation of calcium in the medial axon (>30 min) and subsequently in the terminal branches (>40 min), suggesting that excessive somatic calcium had diffused or induced a propagation along the axon. Corresponding with a 56% rise in terminal calcium (50-60 min post agonist), postsynaptic potentials declined to 70% of baseline amplitude. These results suggest that prolonged somatic L-channel 'leak' can interfere with regulated transmitter release, both by reducing the rate of presynaptic discharge and by promoting terminal calcium accumulation that may oppose transmitter release. Such effect may have implications for the age-related learning deficits that often accompany somatic calcium 'leak'. PMID:12591115

Matzel, Louis D; Han, Yu; Lavie, Mauricio; Gandhi, Chetan C

2003-03-01

112

Acidic deposition--ecological effects on surface waters  

SciTech Connect

The acidification of soft water aquatic ecosystems, with consequent damage to the flora and fauna, is considered in this report. The evidence that environmental effects are ocurring is examined to see if a trend of increasing acidification can be related to changes in atmospheric deposition of sulphates and nitrates. Possible causes of change are considered, to clarify the contributions of variations in human activities and natural factors. It is concluded that acidic deposition, originating partly from emissions of sulphur and nitrogen compounds arising from man-made sources including combustion of fossil fuels, is causing acidification of surface waters in some areas of Europe and North America. There is proof that acidification of surface waters (to less than pH 6) is deleterious to many of the organisms whose habitat it forms. Acidified surface waters in some of the impacted areas are showing signs of recovery, where emissions of sulphur and nitrogen compounds from human activities are decreasing. There is some evidence that reversibility of acidification has started to occur, in some instances, about a decade after emissions were reduced. 219 refs., 13 figs., 9 tabs.

Harter, P.

1989-01-01

113

Digital television's position and effect in the media ecology environment of broadcast and television  

Microsoft Academic Search

Various media owns its living space for its specific dissemination feature and ecological niche with special time and space. This article uses media ecology theory to study the effect and function of digital television on the living environment of television media, with the purpose of analyzing the change for the whole media ecology environment. With the application of basic analysis

Lun Liu

2010-01-01

114

Potential Biological and Ecological Effects of Flickering Artificial Light  

PubMed Central

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

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

2014-01-01

115

[Ecological effects of multifunctional micro-flora agent in environment].  

PubMed

In this paper, strains ZJY-1 (Brevibacillus brevis) and ZJY-116 (Bacillus subtilis) with evident inhibitory effect on Fusarium oxysporum f. sp. cucumerinum and with promotion effect on plant growth were screened from cucumber rhizosphere, and the feasibility of exerting the ecological effects of multifunctional micro-flora agent was studied by treating cucumber seeds with the two strains singly or mixed with chlorpyrifos-degrading strain DSP3 (Alcaligenes faecali). The results showed that the two strains could keep their functions in suppressing disease and promoting plant growth when mixed with DSP3, and the chlorpyrifos-degrading effect of DSP3 had no significant difference when DSP3 was applied singly or mixed with the two strains. This study testified the feasibility of applying multifunctional micro-flora agent in the environment. PMID:16422513

Zhang, Xin; Zhang, Bingxin; Zhao, Yuhua; Yang, Li; Yang, Chinghong; Yu, Jingquan

2005-10-01

116

Ecological effects of the herbicide linuron in tropical freshwater microcosms.  

PubMed

Effects of a single application of the photosynthesis-inhibiting herbicide linuron (0, 15, 50, 150, and 500 microg/L) on the ecology of outdoor plankton-dominated microcosms were studied in Thailand. As a result of the decreased photosynthesis, DO and pH decreased while EC, alkalinity and nutrient concentrations increased. Chlorophytes belonging to the genera Scenedesmus, Coelastrum and Pediastrum were the most sensitive taxa, whereas several other chlorophytes, diatoms, and cryptophytes increased in abundance. Tolerant taxa appeared to be less digestable for several zooplankton taxa, which subsequently decreased in abundances. Chamaesiphon sp. (Cyanobacteria) was the most susceptible periphyton species. As a consequence of functional redundancy, effects of the herbicide on the chlorophyll-a content of periphyton and especially phytoplankton did not always reflect the effects noted on community level. PMID:18718661

Daam, Michiel A; Rodrigues, António M F; Van den Brink, Paul J; Nogueira, António J A

2009-02-01

117

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

PubMed Central

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.

Li, Wen-Hsiung

1979-01-01

118

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

PubMed

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

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

2014-01-10

119

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

PubMed Central

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

Badyaev, Alexander V.; Uller, Tobias

2009-01-01

120

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

EPA Science Inventory

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

121

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

EPA Science Inventory

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

122

Ecological and Evolutionary Effects of Dispersal on Freshwater Zooplankton  

ERIC Educational Resources Information Center

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…

Allen, Michael R.

2009-01-01

123

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

EPA Science Inventory

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

124

THE LOCAL EFFECT TIME (LET) AND HOW IT INCORPORATES ECOLOGY INTO RESIDENCE TIME  

EPA Science Inventory

A clear and direct connection between constituent/water residence times and ecological effects is necessary to quantitatively relate these time scales to ecology. The concept of "local effect time" (LET) is proposed here as a time scale with adequate spatial resolution to relate ...

125

Environmental effects of increased coal utilization ecological effects of gaseous emissions from coal combustion. Final report  

Microsoft Academic Search

This report is provided for the 'Health and Environmental Effects of Coal Utilization' Committee which was created by the request of the DOE in response to the President's Environmental Message. It evaluates ecological environmental effects of gaseous emissions and aerosols of various types which result from coal combustion. The report deals with NOx, SOx fine particulate, photochemical oxidant and acid

1978-01-01

126

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

EPA Science Inventory

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

127

From Bad to Good: Fitness Reversals and the Ascent of Deleterious Mutations  

PubMed Central

Deleterious mutations are considered a major impediment to adaptation, and there are straightforward expectations for the rate at which they accumulate as a function of population size and mutation rate. In a simulation model of an evolving population of asexually replicating RNA molecules, initially deleterious mutations accumulated at rates nearly equal to that of initially beneficial mutations, without impeding evolutionary progress. As the mutation rate was increased within a moderate range, deleterious mutation accumulation and mean fitness improvement both increased. The fixation rates were higher than predicted by many population-genetic models. This seemingly paradoxical result was resolved in part by the observation that, during the time to fixation, the selection coefficient (s) of initially deleterious mutations reversed to confer a selective advantage. Significantly, more than half of the fixations of initially deleterious mutations involved fitness reversals. These fitness reversals had a substantial effect on the total fitness of the genome and thus contributed to its success in the population. Despite the relative importance of fitness reversals, however, the probabilities of fixation for both initially beneficial and initially deleterious mutations were exceedingly small (on the order of 10?5 of all mutations).

Cowperthwaite, Matthew C; Bull, J. J; Meyers, Lauren Ancel

2006-01-01

128

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

PubMed Central

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

Kondrashov, A. S.; Turelli, M.

1992-01-01

129

[Research on evaluation methods of road ecological effects: a case study of Lan-Hai highway].  

PubMed

The ecological effects of roads are systematically and quantitatively evaluated using different methods and metrics in three scales. The small scale effects are assessed by in-situ measurement, the middle scale effects by remote sensing monitoring in different resolution and large scale effects by spatial models based on RS and GIS. The results are satisfactory when this system was applied to Lan-Hai highway. The system can be an important reference to highway ecological effects assessment. PMID:18290456

Mu, Bin; Xie, Yang; Jiang, Nan; Cai, Bo-feng; Yu, Shun-li

2007-12-01

130

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...

131

Extraordinary sex ratios: cultural effects on ecological consequences.  

PubMed

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

Molnár, Ferenc; Caraco, Thomas; Korniss, Gyorgy

2012-01-01

132

Extraordinary Sex Ratios: Cultural Effects on Ecological Consequences  

PubMed Central

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.

Molnar, Ferenc; Caraco, Thomas; Korniss, Gyorgy

2012-01-01

133

Long Runs of Homozygosity Are Enriched for Deleterious Variation  

PubMed Central

Exome sequencing offers the potential to study the population-genomic variables that underlie patterns of deleterious variation. Runs of homozygosity (ROH) are long stretches of consecutive homozygous genotypes probably reflecting segments shared identically by descent as the result of processes such as consanguinity, population size reduction, and natural selection. The relationship between ROH and patterns of predicted deleterious variation can provide insight into the way in which these processes contribute to the maintenance of deleterious variants. Here, we use exome sequencing to examine ROH in relation to the distribution of deleterious variation in 27 individuals of varying levels of apparent inbreeding from 6 human populations. A significantly greater fraction of all genome-wide predicted damaging homozygotes fall in ROH than would be expected from the corresponding fraction of nondamaging homozygotes in ROH (p < 0.001). This pattern is strongest for long ROH (p < 0.05). ROH, and especially long ROH, harbor disproportionately more deleterious homozygotes than would be expected on the basis of the total ROH coverage of the genome and the genomic distribution of nondamaging homozygotes. The results accord with a hypothesis that recent inbreeding, which generates long ROH, enables rare deleterious variants to exist in homozygous form. Thus, just as inbreeding can elevate the occurrence of rare recessive diseases that represent homozygotes for strongly deleterious mutations, inbreeding magnifies the occurrence of mildly deleterious variants as well.

Szpiech, Zachary A.; Xu, Jishu; Pemberton, Trevor J.; Peng, Weiping; Zollner, Sebastian; Rosenberg, Noah A.; Li, Jun Z.

2013-01-01

134

LANDSCAPE-SCALE EFFECTS OF TOXIC EVENTS FOR ECOLOGICAL RISK ASSESSMENT  

EPA Science Inventory

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

135

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

EPA Science Inventory

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

136

An Ecological Theory of Expertise Effects in Memory Recall.  

ERIC Educational Resources Information Center

A novel theory based on an ecological approach is proposed to explain the significant correlation between domain expertise and memory recall after a short period of time. This constraint attunement hypothesis provides a framework for identifying and representing the various levels of goal-relevant constraint as a domain. (SLD)

Vicente, Kim J.; Wang, JoAnne H.

1998-01-01

137

Landscape ecology: the effect of pattern on process  

Microsoft Academic Search

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

Monica Goigel Turner

1989-01-01

138

Ecological Effects of Weather Modification: A Problem Analysis.  

ERIC Educational Resources Information Center

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

Cooper, Charles F.; Jolly, William C.

139

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

Microsoft Academic Search

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 µg 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

Evelyn E. Gaiser; Joel C. Trexler; Jennifer H. Richards; Daniel L. Childers; David W. Lee; Adrienne L. Edwards; Leonard J. Scinto; Krish Jayachandran; Gregory B. Noe; Ronald D. Jones

2005-01-01

140

A Catalog of Neutral and Deleterious Polymorphism in Yeast  

PubMed Central

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

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

2008-01-01

141

Effects of air pollution on biogenic volatiles and ecological interactions  

Microsoft Academic Search

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

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

2009-01-01

142

Ecological effects of soil contamination at Aberdeen Proving Ground, Maryland  

SciTech Connect

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

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

1994-06-01

143

The inevitability of unconditionally deleterious substitutions during adaptation.  

PubMed

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

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

2014-05-01

144

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

PubMed Central

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

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

2013-01-01

145

From roadkill to road ecology: A review of the ecological effects of roads  

Microsoft Academic Search

Transportation infrastructure affects the structure of ecosystems, the dynamics of ecosystem function, and has direct effects on ecosystem components, including their species composition. Clearly, the construction of transport lines results in the direct destruction and removal of existing ecosystems, and the reconfiguration of local landforms. However, transportation systems, and more specifically, roads, have a wide variety of primary, or direct,

Alisa W. Coffin

2007-01-01

146

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

PubMed Central

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.

Glass, N R

1979-01-01

147

Warfare Ecology  

NSDL National Science Digital Library

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.

Gary E. Machlis (University of Idaho;); Thor Hanson (University of Idaho;)

2008-09-01

148

Ecological Modeling for the Extrapolation of Ecotoxicological Effects Measured during in Situ Assays in Gammarus.  

PubMed

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

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

2014-06-01

149

Inbreeding Depression and Inferred Deleterious-Mutation Parameters in Daphnia  

PubMed Central

DENG and LYNCH recently proposed a method for estimating deleterious genomic mutation parameters from changes in the mean and genetic variance of fitness traits upon inbreeding in outcrossing populations. Such observations are readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. We observed a significant inbreeding depression and an increase of genetic variance for all traits analyzed. DENG and LYNCH's original procedures were extended to estimate genomic mutation rate (U), mean dominance coefficient (h), mean selection coefficient (s), and scaled genomic mutational variance (V(m)/V(e)). On average, U, h, s and V(m)/V(e) (^ indicates an estimate) are 0.74, 0.30, 0.14 and 4.6E-4, respectively. For the true values, the U and h are lower bounds, and s and V(m)/V(e) upper bounds. The present U, h and V(m)/V(e) are in general concordance with earlier results. The discrepancy between the present s and that from mutation-accumulation experiments in Drosophila (~0.04) is discussed. It is shown that different reproductive modes do not affect gene frequency at mutation-selection equilibrium if mutational effects on fitness are multiplicative and not completely recessive.

Deng, H. W.; Lynch, M.

1997-01-01

150

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

PubMed

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

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

2013-10-01

151

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)

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.

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

2013-12-01

152

Prevention of deleterious deposits in a coal liquefaction system  

DOEpatents

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

Carr, Norman L. (Allison Park, PA); Prudich, Michael E. (Pittsburgh, PA); King, Jr., William E. (Gibsonia, PA); Moon, William G. (Cheswick, PA)

1984-07-03

153

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

Microsoft Academic Search

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

N. Canibe; B. B. Jensen

2007-01-01

154

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

ERIC Educational Resources Information Center

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

Niesenbaum, Richard A.; Gorka, Barbara

2001-01-01

155

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

Microsoft Academic Search

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

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

156

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

Microsoft Academic Search

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

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

157

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...

158

Using Reproductuve and Developmental Effects Data in Ecological Risk Assessments for Oviparous Vertebrates Exposed To Contaminants.  

National Technical Information Service (NTIS)

Ecological Risk Assessment (ERA) is a tool often used to support risk-based decision-making. An essential step in the process of applying reproductive and developmental effects data within a risk assessment context is developing an understanding of how th...

J. R. Clark K. L. Dickson J. P. Giesy R. T. Lackey E. M. Mihaich R. G. Stahl M. G. Zeeman

1998-01-01

159

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

ERIC Educational Resources Information Center

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

Bruyere, Brett L.

2008-01-01

160

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

Microsoft Academic Search

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

Julio A. Camargo; Álvaro Alonso

2006-01-01

161

The Effect of Conceptual Change Approach on Students' Ecology Achievement and Attitude towards Biology  

ERIC Educational Resources Information Center

This study investigated the effectiveness of conceptual change texts oriented instruction accompanied by demonstrations in small groups on students' ecology achievement and attitude towards biology. 78 ninth grade students in a public high school participated in this study. While the control group was taught with the traditional method, the…

Cetin, Gulcan; Ertepinar, Hamide; Geban, Omer

2004-01-01

162

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...

163

An evaluation of the effectivity of the scrub technique in quantitative ectoparasite ecology  

Microsoft Academic Search

The effectivity of the scrub technique used in quantitative parasite ecology to collect ectoparasites from mammalian skins was evaluated. This was done by reprocessing already scrubbed skins with the alkali digestion technique to remove any remaining parasites. The skins of six adult impala (Aepyceros melampus) ewes were used in the study. The results showed that the scrub technique is variable

Peet J. van Dyk; Andrew A. McKenzie

1992-01-01

164

Evolutionary and Ecological Effects of Multi-Generational Exposures to Anthropogenic Stressors  

Microsoft Academic Search

Biological and ecological responses to stress are dictated by duration and frequency, as well as instantaneous magnitude. Conditional compensatory responses at the physiological and behavioral levels, referred to as ‘acclimation’, may mitigate effects on individuals experiencing brief or infrequent periods of moderate stress. However, even modest stress over extended periods may reduce the fitness of some or all exposed individuals.

Diane E. Nacci; Timothy R. Gleason; Wayne R. Munns

2002-01-01

165

On the average coefficient of dominance of deleterious spontaneous mutations.  

PubMed

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

García-Dorado, A; Caballero, A

2000-08-01

166

Contrasted Effects of Diversity and Immigration on Ecological Insurance in Marine Bacterioplankton Communities  

PubMed Central

The ecological insurance hypothesis predicts a positive effect of species richness on ecosystem functioning in a variable environment. This effect stems from temporal and spatial complementarity among species within metacommunities coupled with optimal levels of dispersal. Despite its importance in the context of global change by human activities, empirical evidence for ecological insurance remains scarce and controversial. Here we use natural aquatic bacterial communities to explore some of the predictions of the spatial and temporal aspects of the ecological insurance hypothesis. Addressing ecological insurance with bacterioplankton is of strong relevance given their central role in fundamental ecosystem processes. Our experimental set up consisted of water and bacterioplankton communities from two contrasting coastal lagoons. In order to mimic environmental fluctuations, the bacterioplankton community from one lagoon was successively transferred between tanks containing water from each of the two lagoons. We manipulated initial bacterial diversity for experimental communities and immigration during the experiment. We found that the abundance and production of bacterioplankton communities was higher and more stable (lower temporal variance) for treatments with high initial bacterial diversity. Immigration was only marginally beneficial to bacterial communities, probably because microbial communities operate at different time scales compared to the frequency of perturbation selected in this study, and of their intrinsic high physiologic plasticity. Such local “physiological insurance” may have a strong significance for the maintenance of bacterial abundance and production in the face of environmental perturbations.

Bouvier, Corinne; Barbera, Claire; Mouquet, Nicolas

2012-01-01

167

Computational Methods to Work as First-Pass Filter in Deleterious SNP Analysis of Alkaptonuria  

PubMed Central

A major challenge in the analysis of human genetic variation is to distinguish functional from nonfunctional SNPs. Discovering these functional SNPs is one of the main goals of modern genetics and genomics studies. There is a need to effectively and efficiently identify functionally important nsSNPs which may be deleterious or disease causing and to identify their molecular effects. The prediction of phenotype of nsSNPs by computational analysis may provide a good way to explore the function of nsSNPs and its relationship with susceptibility to disease. In this context, we surveyed and compared variation databases along with in silico prediction programs to assess the effects of deleterious functional variants on protein functions. In other respects, we attempted these methods to work as first-pass filter to identify the deleterious substitutions worth pursuing for further experimental research. In this analysis, we used the existing computational methods to explore the mutation-structure-function relationship in HGD gene causing alkaptonuria.

Magesh, R.; George Priya Doss, C.

2012-01-01

168

Amino acid composition of proteins reduces deleterious impact of mutations.  

PubMed

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

Hormoz, Sahand

2013-01-01

169

Amino acid composition of proteins reduces deleterious impact of mutations  

PubMed Central

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

Hormoz, Sahand

2013-01-01

170

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

SciTech Connect

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.

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

2006-10-24

171

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...

172

ECOLOGICAL EXPOSURE AND EFFECTS OF AIRBORNE TOXIC CHEMICALS: AN OVERVIEW  

EPA Science Inventory

Since the release of the Environmental Protection Agency's (EPA's) toxic release inventory (TRI) estimates for 1987, there has been a heightened concern over the nation's air quality. rimarily, this concern has been directed at human health effects in industrial-urban areas. he f...

173

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

PubMed

Mercury at low concentrations represents a major hazard to microorganisms. Inorganic mercury has been reported to produce harmful effects at 5 microg/l in a culture medium. Organomercury compounds can exert the same effect at concentrations 10 times lower than this. The organic forms of mercury are generally more toxic to aquatic organisms and birds than the inorganic forms. Aquatic plants are affected by mercury in water at concentrations of 1 mg/l for inorganic mercury and at much lower concentrations of organic mercury. Aquatic invertebrates widely vary in their susceptibility to mercury. In general, organisms in the larval stage are most sensitive. Methyl mercury in fish is caused by bacterial methylation of inorganic mercury, either in the environment or in bacteria associated with fish gills or gut. In aquatic matrices, mercury toxicity is affected by temperature, salinity, dissolved oxygen and water hardness. A wide variety of physiological, reproductive and biochemical abnormalities have been reported in fish exposed to sublethal concentrations of mercury. Birds fed inorganic mercury show a reduction in food intake and consequent poor growth. Other (more subtle) effects in avian receptors have been reported (i.e., increased enzyme production, decreased cardiovascular function, blood parameter changes, immune response, kidney function and structure, and behavioral changes). The form of retained mercury in birds is more variable and depends on species, target organ and geographical site. With few exceptions, terrestrial plants (woody plants in particular) are generally insensitive to the harmful effects of mercury compounds. PMID:10789973

Boening, D W

2000-06-01

174

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

175

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

PubMed Central

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.

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

2013-01-01

176

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

SciTech Connect

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.

AIMEE J. WELDON; NICK M. HADDAD

2005-01-01

177

Ecological toxicology and human health effects of heptachlor.  

PubMed

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

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

1990-01-01

178

Protective effect from solar exposure, risk of an ecological fallacy.  

PubMed

Solar exposure, vitamin D, and their possible beneficial effect on cancer risk and cancer prognosis are a topic for research. Despite the distinct nature of sunlight, it has proved difficult to assess the exposure quantitatively in epidemiological studies. Skin cancers, latitude, and sunny climate have been used as proxy indicators of solar exposure above a reference level. The interpretation of such data may still be hampered by incomplete cancer registration, difference in protection against sunbeams, selection mechanisms, and absence of information on potential confounders. A recently published paper -- on second primary cancer following the diagnosis of a skin cancer -- is discussed to illustrate the difficulties. Further epidemiological studies of potentially protective effects from carcinogenic ultraviolet rays should include individual information on solar exposure and vitamin D levels, as well as on other recognised and relevant risk factors. PMID:18061436

Grimsrud, Tom K; Andersen, Aage

2008-01-01

179

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.

180

Effects of Partially Anadromous Arctic Charr ( Salvelinus alpinus ) Populations on Ecology of Coastal Arctic Lakes  

Microsoft Academic Search

Little research has been conducted on effects of iteroparous anadromous fishes on Arctic lakes. We investigated trophic ecology,\\u000a fish growth, and food web structure in six lakes located in Nunavut, Canada; three lakes contained anadromous Arctic charr\\u000a (Salvelinus alpinus) whereas three lakes did not contain Arctic charr. All lakes contained forage fishes and lake trout (Salvelinus namaycush; top predator). Isotope

Heidi K. Swanson; Karen A. Kidd; James D. Reist

2010-01-01

181

Community metabolism of aquatic Closed Ecological Systems: Effects of nitrogen sources  

Microsoft Academic Search

To investigate the effect of nitrogen sources on Closed Ecological Systems (CESs), three nitrogen sources (NaNO3, sodium nitrate; NH4Cl, ammonium chloride; and NH4NO3, ammonium nitrate) were each tested in freshwater CESs consisting of a chemically defined medium, three species of green algae (Ankistrodesmus, Scenedesmus, and Selenastrum), the grazer Daphnia magna, and associated microbes, under 12h light\\/12h dark cycles. It had

Frieda B. Taub

2009-01-01

182

Community metabolism of aquatic Closed Ecological Systems: Effects of nitrogen sources  

Microsoft Academic Search

To investigate the effect of nitrogen sources on Closed Ecological Systems (CESs), three nitrogen sources (NaNO3, sodium nitrate; NH4Cl, ammonium chloride; and NH4NO3, ammonium nitrate) were each tested in freshwater CESs consisting of a chemically defined medium, three species of green algae (Ankistrodesmus, Scenedesmus, and Selenastrum), the grazer Daphnia magna, and associated microbes, under 12 h light\\/12 h dark cycles.

Frieda B. Taub

2009-01-01

183

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

PubMed

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. PMID:12481804

Rygalov, Vadim Y; Fowler, Philip A; Metz, Joannah M; Wheeler, Raymond M; Bucklin, Ray A

2002-01-01

184

Water cycles in closed ecological systems: effects of atmospheric pressure  

NASA Technical Reports Server (NTRS)

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.

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

2002-01-01

185

Ecological Effects of Perorally Administered Pivmecillinam on the Normal Vaginal Microflora  

PubMed Central

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

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

2005-01-01

186

[Physiological and ecological effects of inter- and mixed cropping rape with milk vetch].  

PubMed

The investigation on the growth, yield and benefit of rape inter- and mixed cropped with milk vetch showed that comparing with sowing rape under zero tillage, the physiological and ecological characters of transplanted rape, including its height, leaf size, root diameter, opening degree and yield were obviously improved. Under zero tillage, mixed cropping had an obvious advantage than inter- and single cropping. After tillage, the yield of transplanted rape under mixed cropping was 11.9% more than that under single cropping with zero tillage. The benefit of transplanting rape under mixed cropping with tillage was the biggest, followed by single cropping rape with zero tillage. It could be concluded that the patterns of transplanting rape under mixed cropping after tillage and zero tillage had the best physiological and ecological effects, not only increasing rape yield and income, but also improving soil fertility. PMID:16262062

Zhou, Kejin; Xing, Jun; Bo, Yuhong; Sang, Yasong; Wu, Shelan; Song, Guoliang

2005-08-01

187

Effects of Increasing Urbanization on the Ecological Integrity of Open Space Preserves  

NASA Astrophysics Data System (ADS)

This article analyzes the effects of increasing urbanization on open space preserves within the metropolitan area of Phoenix, Arizona, USA. Time series analysis is used in 10-year increments over 40 years to study urban landscape change. Three landscape metrics—(1) matrix utility (measures intensity of adjacent land uses), (2) isolation (measures distances to other open space patches), and (3) connectivity (measures physical links to other open space patches and corridors)—are used to assess changes in landscape patterns and serve as indicators of urban ecological integrity of the open space preserves. Results show that in the case of both open space preserves, general decline in indicators of urban ecological integrity was evident. The matrix utility analysis demonstrated that increasing intensity of land uses adjacent to preserve is likely to increase edge effects, reducing the habitat value of interior or core habitat areas. Isolation analysis showed that both preserves have experienced increasing isolation from other open space elements over time. Also, connectivity analysis indicated that terrestrial connections to other open space elements have also deteriorated. Conclusions of this research demonstrate that while preservation of natural areas as open space is important in an urban context, intense development of surrounding areas reduces the urban ecological integrity significantly.

Esbah, Hayriye; Cook, Edward A.; Ewan, Joseph

2009-05-01

188

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

USGS Publications Warehouse

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.

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

2012-01-01

189

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

EPA Science Inventory

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

190

Ecological Effects.  

National Technical Information Service (NTIS)

The biological significance of environmental impacts at the community and ecosystem levels are considered, along with the cost to society of irreversible damages at these levels. The costs, risks, and benefits of alternative developments are evaluated wit...

W. E. Cooper L. Crowder C. Olive

1976-01-01

191

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

Cancer.gov

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

192

ERTS-1 investigation of ecological effects of strip mining in eastern Ohio  

NASA Technical Reports Server (NTRS)

Evidence is presented of ERTS capability to detect, map and monitor the effects of strip mining. Both enlarge ERTS imagery and statistically processed outline maps and imagery of stripped earth and standing water are compared to aerial photos of a strip mine near Coshocton, Ohio. The outline maps and decision imagery are at present limited to forming a disruption map of recently mined and unreclaimed earth and the resultant standing water within the mined area. It is planned to prepare a map of the reclaimed areas (reclamation map) within the stripped area and to detect and identify ecological effects such as vegetation kills and stream sedimentation external to the stripped areas.

Chase, P. E.; Pettyjohn, W. A.

1973-01-01

193

An evaluation of the effectivity of the scrub technique in quantitative ectoparasite ecology.  

PubMed

The effectivity of the scrub technique used in quantitative parasite ecology to collect ectoparasites from mammalian skins was evaluated. This was done by reprocessing already scrubbed skins with the alkali digestion technique to remove any remaining parasites. The skins of six adult impala (Aepyceros melampus) ewes were used in the study. The results showed that the scrub technique is variable in its effectivity, and on average removed only 30.2% ectoparasites from the skins. It was also shown that the scrub technique is unreliable and more labour intensive and time consuming than the digestion technique, and should preferably not be used in quantitative studies. PMID:1451610

van Dyk, P J; McKenzie, A A

1992-10-01

194

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

PubMed

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

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

2014-05-01

195

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

PubMed

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

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

2003-03-01

196

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

PubMed Central

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.

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

2009-01-01

197

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

PubMed

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

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

2005-06-01

198

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

NASA Astrophysics Data System (ADS)

Urbanization almost inevitably results in changes to stream morphology. Understanding the mechanisms for such impacts is a prerequisite to minimizing stream degradation and achieving restoration goals. However, investigations of urban-induced changes to stream morphology typically use indicators of watershed urbanization that may not adequately represent degrading mechanisms and commonly focus on geomorphic attributes such as channel dimensions that may be of little significance to the ecological goals for restoration. We address these shortcomings by testing if a measure characterizing urban stormwater drainage system connections to streams (effective imperviousness, EI) is a better predictor of change to ecologically relevant geomorphic attributes than a more general measure of urban density (total imperviousness, TI). We test this for 17 sites in independent watersheds across a gradient of urbanization. We found that EI was a better predictor of all geomorphic variables tested than was TI. Bank instability was positively correlated with EI, while width/depth (a measure of channel incision), bedload sediment depth, and frequency of bars, benches, and large wood were negatively correlated. Large changes in all geomorphic variables were detected at very low levels of EI (< 2-3%). Excess urban stormwater runoff, as represented by EI, drives geomorphic change in urban streams, highlighting the dominant role of the stormwater drainage system in efficiently transferring stormwater runoff from impervious surfaces to the stream, as found for ecological indicators. It is likely that geomorphic condition of streams in urbanizing watersheds, particularly those attributes of ecological relevance, can only be maintained if excess urban stormwater flows are kept out of streams through retention and harvesting. The extent to which EI can be reduced within urban and urbanizing watersheds, through techniques such as distributed stormwater harvesting and infiltration, and the components of the hydrologic regime to be addressed, requires further investigation.

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

2014-02-01

199

Antagonistic coevolution with parasites increases the cost of host deleterious mutations  

Microsoft Academic Search

The fitness consequences of deleterious mutations are sometimes greater when individuals are parasitized, hence parasites may result in the more rapid purging of deleterious mutations from host populations. The significance of host deleterious mutations when hosts and parasites antagonistically coevolve (reciprocal evolution of host resistance and parasite infectivity) has not previously been experimentally investigated. We addressed this by coevolving the

Angus Buckling; Yan Wei; Ruth C. Massey; Michael A. Brockhurst; Michael E. Hochberg

2005-01-01

200

Ecology, Microbial  

SciTech Connect

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

Konopka, Allan

2009-03-19

201

Ecology, Microbial  

SciTech Connect

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

Konopka, Allan

2009-05-15

202

Community ecology theory predicts the effects of agrochemical mixtures on aquatic biodiversity and ecosystem properties.  

PubMed

Ecosystems are often exposed to mixtures of chemical contaminants, but the scientific community lacks a theoretical framework to predict the effects of mixtures on biodiversity and ecosystem properties. We conducted a freshwater mesocosm experiment to examine the effects of pairwise agrochemical mixtures [fertiliser, herbicide (atrazine), insecticide (malathion) and fungicide (chlorothalonil)] on 24 species- and seven ecosystem-level responses. As postulated, the responses of biodiversity and ecosystem properties to agrochemicals alone and in mixtures was predictable by integrating information on each functional group's (1) sensitivity to the chemicals (direct effects), (2) reproductive rates (recovery rates), (3) interaction strength with other functional groups (indirect effects) and (4) links to ecosystem properties. These results show that community ecology theory holds promise for predicting the effects of contaminant mixtures on biodiversity and ecosystem services and yields recommendations on which types of agrochemicals to apply together and separately to reduce their impacts on aquatic ecosystems. PMID:24811760

Halstead, Neal T; McMahon, Taegan A; Johnson, Steve A; Raffel, Thomas R; Romansic, John M; Crumrine, Patrick W; Rohr, Jason R

2014-08-01

203

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

NASA Astrophysics Data System (ADS)

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

Petursdottir, Thorunn; Finger, David

2014-05-01

204

Reversing deleterious protein aggregation with re-engineered protein disaggregases.  

PubMed

Aberrant protein folding is severely problematic and manifests in numerous disorders, including amyotrophic lateral sclerosis (ALS), Parkinson disease (PD), Huntington disease (HD), and Alzheimer disease (AD). Patients with each of these disorders are characterized by the accumulation of mislocalized protein deposits. Treatments for these disorders remain palliative, and no available therapeutics eliminate the underlying toxic conformers. An intriguing approach to reverse deleterious protein misfolding is to upregulate chaperones to restore proteostasis. We recently reported our work to re-engineer a prion disaggregase from yeast, Hsp104, to reverse protein misfolding implicated in human disease. These potentiated Hsp104 variants suppress TDP-43, FUS, and ?-synuclein toxicity in yeast, eliminate aggregates, reverse cellular mislocalization, and suppress dopaminergic neurodegeneration in an animal model of PD. Here, we discuss this work and its context, as well as approaches for further developing potentiated Hsp104 variants for application in reversing protein-misfolding disorders. PMID:24694655

Jackrel, Meredith E; Shorter, James

2014-05-01

205

Inferring Deleterious-Mutation Parameters in Natural Daphnia Populations  

PubMed Central

Deng and Lynch (1, 2) proposed to characterize deleterious genomic mutations from changes in the mean and genetic variance of fitness traits upon selfing in outcrossing populations. Such observations can be readily acquired in cyclical parthenogens. Selfing and life-table experiments were performed for two such Daphnia populations. A significant inbreeding depression and an increase of genetic variance for all traits analyzed were observed. Deng and Lynch's (2) procedures were employed to estimate the genomic mutation rate (U), mean dominance coefficient ( ), mean selection coefficient ( ), and scaled genomic mutational variance ( ). On average, , , and (^ indicates an estimate) are 0.84, 0.30, 0.14 and 4.6E-4 respectively. For the true values, the and are lower bounds, and and upper bounds.

1998-01-01

206

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

PubMed Central

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.

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

2014-01-01

207

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

PubMed

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

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

2012-06-01

208

Ecological Schoolyards.  

ERIC Educational Resources Information Center

Presents design guidelines and organizational and site principles for creating schoolyards where students can learn about ecology. Principles for building schoolyard ecological systems are described. (GR)

Danks, Sharon Gamson

2000-01-01

209

How to characterize chemical exposure to predict ecologic effects on aquatic communities?  

PubMed

Reliable characterization of exposure is indispensable for ecological risk assessment of chemicals. To deal with mixtures, several approaches have been developed, but their relevance for predicting ecological effects on communities in the field has not been elucidated. In the present study, we compared nine metrics designed for estimating the total toxicity of mixtures regarding their relationship with an effect metric for stream macroinvertebrates. This was done using monitoring data of biota and organic chemicals, mainly pesticides, from five studies comprising 102 streams in several regions of Europe and South-East Australia. Mixtures of less than 10 pesticides per water sample were most common for concurrent exposure. Exposure metrics based on the 5% fraction of a species sensitivity distribution performed best, closely followed by metrics based on the most sensitive species and Daphnia magna as benchmark. Considering only the compound with the highest toxicity and ignoring mixture toxicity was sufficient to estimate toxicity in predominantly agricultural regions with pesticide exposure. The multisubstance Potentially Affected Fraction (msPAF) that combines concentration and response addition was advantageous in the study where further organic toxicants occurred. We give recommendations on exposure metric selection depending on data availability and the involved compounds. PMID:23763297

Schäfer, Ralf B; Gerner, Nadine; Kefford, Ben J; Rasmussen, Jes J; Beketov, Mikhail A; de Zwart, Dick; Liess, Matthias; von der Ohe, Peter C

2013-07-16

210

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

PubMed

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

Doi, Masahiro; Kawaguchi, Isao

2007-01-01

211

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

USGS Publications Warehouse

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.

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

212

Ecological effects of various toxic agents on the aquatic microcosm in comparison with acute ionizing radiation.  

PubMed

The purpose of this study was an evaluation of the effect levels of various toxic agents compared with acute doses of ionizing radiation for the experimental model ecosystem, i.e., microcosm mimicking aquatic microbial communities. For this purpose, the authors used the microcosm consisting of populations of the flagellate alga Euglena gracilis as a producer, the ciliate protozoan Tetrahymena thermophila as a consumer and the bacterium Escherichia coli as a decomposer. Effects of aluminum and copper on the microcosm were investigated in this study, while effects of gamma-rays, ultraviolet radiation, acidification, manganese, nickel and gadolinium were reported in previous studies. The microcosm could detect not only the direct effects of these agents but also the community-level effects due to the interspecies interactions or the interactions between organisms and toxic agents. The authors evaluated doses or concentrations of each toxic agent which had the following effects on the microcosm: (1) no effects; (2) recognizable effects, i.e., decrease or increase in the cell densities of at least one species; (3) severe effects, i.e., extinction of one or two species; and (4) destructive effects, i.e., extinction of all species. The resulting effects data will contribute to an ecological risk assessment of the toxic agents compared with acute doses of ionizing radiation. PMID:12633997

Fuma, S; Ishii, N; Takeda, H; Miyamoto, K; Yanagisawa, K; Ichimasa, Y; Saito, M; Kawabata, Z; Polikarpov, G G

2003-01-01

213

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

PubMed

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

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

2014-05-01

214

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

PubMed

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

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

2012-02-01

215

Allelic Expression of Deleterious Protein-Coding Variants across Human Tissues  

PubMed Central

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

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

2014-01-01

216

In Silico profiling of deleterious amino acid substitutions of potential pathological importance in haemophlia A and haemophlia B  

PubMed Central

Background In this study, instead of current biochemical methods, the effects of deleterious amino acid substitutions in F8 and F9 gene upon protein structure and function were assayed by means of computational methods and information from the databases. Deleterious substitutions of F8 and F9 are responsible for Haemophilia A and Haemophilia B which is the most common genetic disease of coagulation disorders in blood. Yet, distinguishing deleterious variants of F8 and F9 from the massive amount of nonfunctional variants that occur within a single genome is a significant challenge. Methods We performed an in silico analysis of deleterious mutations and their protein structure changes in order to analyze the correlation between mutation and disease. Deleterious nsSNPs were categorized based on empirical based and support vector machine based methods to predict the impact on protein functions. Furthermore, we modeled mutant proteins and compared them with the native protein for analysis of protein structure stability. Results Out of 510 nsSNPs in F8, 378 nsSNPs (74%) were predicted to be 'intolerant' by SIFT, 371 nsSNPs (73%) were predicted to be 'damaging' by PolyPhen and 445 nsSNPs (87%) as 'less stable' by I-Mutant2.0. In F9, 129 nsSNPs (78%) were predicted to be intolerant by SIFT, 131 nsSNPs (79%) were predicted to be damaging by PolyPhen and 150 nsSNPs (90%) as less stable by I-Mutant2.0. Overall, we found that I-Mutant which emphasizes support vector machine based method outperformed SIFT and PolyPhen in prediction of deleterious nsSNPs in both F8 and F9. Conclusions The models built in this work would be appropriate for predicting the deleterious amino acid substitutions and their functions in gene regulation which would be useful for further genotype-phenotype researches as well as the pharmacogenetics studies. These in silico tools, despite being helpful in providing information about the nature of mutations, may also function as a first-pass filter to determine the substitutions worth pursuing for further experimental research in other coagulation disorder causing genes.

2012-01-01

217

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

USGS Publications Warehouse

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.

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

1995-01-01

218

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

PubMed

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

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

2014-01-01

219

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

PubMed Central

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

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

2014-01-01

220

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

PubMed Central

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.

Carbon, Claus-Christian; Ditye, Thomas

2012-01-01

221

Political ecology and ecological resilience  

Microsoft Academic Search

The biosphere is increasingly dominated by human action. Consequently, ecology must incorporate human behavior. Political ecology, as long as it includes ecology, is a powerful framework for integrating natural and social dynamics. In this paper I present a resilience-oriented approach to political ecology that integrates system dynamics, scale, and cross-scale interactions in both human and natural systems. This approach suggests

Garry Peterson

2000-01-01

222

Analysis of ecological effects of geopressured-geothermal resource development. Geopressured-geothermal technical paper No. 4  

SciTech Connect

The activities involved in geopressured-geothermal resource production are identified and their ecological impacts are discussed. The analysis separates those activites that are unique to geopressured-geothermal development from those that also occur in oil and gas and other resource developments. Of the unique activities, those with the greatest potential for serious ecological effect are: (1) accidental brine discharge as a result of a blowout during well drilling; (2) subsidence; (3) fault activation and enhanced seismicity; and (4) subsurface contamination of water, hydrocarbon, and mineral reservoirs. Available methods to predict and control these effects are discussed.

Not Available

1979-07-01

223

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

SciTech Connect

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

Not Available

1980-05-01

224

A Daphnia magna feeding bioassay as a cost effective and ecological relevant sublethal toxicity test for Environmental Risk Assessment of toxic effluents  

Microsoft Academic Search

Environmental Risk Assessment of chemical products and effluents within EC countries require the use of cost effective standardized toxicity tests that in most cases are restricted to acute responses to high doses. Thus, subtle ecological effects are underestimated. Here we propose a short-term one day Daphnia magna feeding inhibition test as a cost effective and ecological relevant sublethal bioassay. The

C. Barata; P. Alañon; S. Gutierrez-Alonso; M. C. Riva; C. Fernández; J. V. Tarazona

2008-01-01

225

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

SciTech Connect

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

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

1989-01-06

226

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

PubMed

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

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

2013-09-01

227

The ChimERA project: coupling mechanistic exposure and effect models into an integrated platform for ecological risk assessment.  

PubMed

Current techniques for the ecological risk assessment of chemical substances are often criticised for their lack of environmental realism, ecological relevance and methodological accuracy. ChimERA is a 3-year project (2013-2016), funded by Cefic's Long Range Initiative (LRI) that aims to address some of these concerns by developing and testing mechanistic fate and effect models, and coupling of these models into one integrated platform for risk assessment. This paper discusses the backdrop against which this project was initiated and lists its objectives and planned methodology. PMID:24532207

De Laender, F; van den Brink, Paul J; Janssen, Colin R; Di Guardo, Antonio

2014-05-01

228

Ecological risk assessment of multimedia hazardous air pollutants: estimating exposure and effects  

Microsoft Academic Search

Hazardous air pollutants, some of which have the potential for multimedia distribution, raise several hurdles for ecological risk assessment including: (1) the development of an adequate transport, fate and exposure model; and (2) the selection of exposure–response models that can accommodate multiple exposure routes for ecological receptors. To address the first issue, the EPA Office of Air Quality Planning and

Rebecca A Efroymson; Deirdre L Murphy

2001-01-01

229

Ecological effectiveness of French grassland agri-environment schemes for farmland bird communities.  

PubMed

Agri-environment schemes (AES) have been implemented to cope with the loss of farmland biodiversity due to agricultural intensification over the last decades. In France, grassland measures (more closely linked to extensive grazing) are the most widely implemented within the French AES, and are presumably those whose effectiveness can be better assessed. In this paper, we have evaluated the effectiveness of French grassland agri-environmental measures (gAES) to enhance farmland bird diversity on a national scale, using local abundances of 19 farmland breeding birds within 463 Small Agricultural Regions (SAR) covering France during 2001-2008. We modeled responses of species abundances and estimated species richness to five categories of grassland AES, accounting for the characteristics of local production systems. Extensive management of grasslands had a positive effect on species richness. Despite mixed results on the effectiveness of the different grassland AES categories, our results are optimistic in terms of the ability of some French AES to provide benefits to birds. It seems that some grassland AES have achieved their objectives while meeting species ecological requirements. Moreover, this study highlights the fact that some of these grassland AES have the potential to enhance the population dynamics of declining species. Finally, although they all aim at benefitting biodiversity, it cannot be assumed that grassland measures lead to uniform conservation benefits. PMID:23535512

Princé, Karine; Jiguet, Frédéric

2013-05-30

230

Effective and ecological half-lives of 137Cs in cow's milk in alpine agriculture.  

PubMed

In the mountainous "Hohe Tauern" region of Salzburg (Austria), milk samples have been collected in a long-term montitoring programme since 1988, at eight alpine sites used for extensive, seasonal stock farming. For this alpine environment with its acidic soils developed on silicate bedrock, high soil-to-plant transfer factors and long-lasting (137)Cs contamination levels in milk--the main product of seasonal agriculture at elevated altitudes--are characteristic features. The decrease in (137)Cs concentration in milk measured since 1988 turned out to be best described by one or two effective half-lives. For the period from 1993 to 2007, which can be modelled with one effective half-life for all sites, effective half-lives between 3.7 and 15.0 years (ecological half-lives: 4.3-29.9 years) were obtained. The effective half-life increases with mean altitude of the investigated graze pastures, probably due to reduced migration velocities of (137)Cs and low (137)Cs half-value depths of a few centimetres in the soil. PMID:18797910

Lettner, Herbert; Hubmer, Alexander; Bossew, Peter; Strebl, Friederike; Steinhäusler, Friedrich

2009-02-01

231

Risk assessment and ecological effects of transgenic Bacillus thuringiensis crops on non-target organisms.  

PubMed

The application of recombinant DNA technology has resulted in many insect-resistant varieties by genetic engineering (GE). Crops expressing Cry toxins derived from Bacillus thuringiensis (Bt) have been planted worldwide, and are an effective tool for pest control. However, one ecological concern regarding the potential effects of insect-resistant GE plants on non-target organisms (NTOs) has been continually debated. In the present study, we briefly summarize the data regarding the development and commercial use of transgenic Bt varieties, elaborate on the procedure and methods for assessing the non-target effects of insect-resistant GE plants, and synthetically analyze the related research results, mostly those published between 2005 and 2010. A mass of laboratory and field studies have shown that the currently available Bt crops have no direct detrimental effects on NTOs due to their narrow spectrum of activity, and Bt crops are increasing the abundance of some beneficial insects and improving the natural control of specific pests. The use of Bt crops, such as Bt maize and Bt cotton, results in significant reductions of insecticide application and clear benefits on the environment and farmer health. Consequently, Bt crops can be a useful component of integrated pest management systems to protect the crop from targeted pests. PMID:21564541

Yu, Hui-Lin; Li, Yun-He; Wu, Kong-Ming

2011-07-01

232

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

Microsoft Academic Search

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

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

2010-01-01

233

Ecological Effects of Highway Construction Upon Michigan Woodlots and Wetlands. Summary of Study Findings Phase 1 Report.  

National Technical Information Service (NTIS)

To determine the ecological effects of highway construction and use upon Michigan woodlots and wetlands, ten sites located along a 45-mile segment of I-75 between Roscommon and West Branch were studied. These sites were examined in respect to several natu...

P. B. Davis C. R. Humphrys

1977-01-01

234

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...

235

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...

236

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

ERIC Educational Resources Information Center

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.…

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

2009-01-01

237

The ecological effects of mining discharges on subtidal habitats dominated by macroalgae in northern Chile: population and community level studies  

Microsoft Academic Search

In 1996\\/97, a study was carried out to evaluate several variables related to the potential ecological effects of soluble copper and iron released as the result of direct dumping of mine tailing into the littoral zone of the Pacific Ocean off northern Chile. Variables studied included:

J. A. Vásquez; J. M. A. Vega; B. Matsuhiro; C. Urzüa

1999-01-01

238

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...

239

Rates of deleterious mutation and the evolution of sex in Caenorhabditis  

Microsoft Academic Search

A variety of models propose that the accumulation of deleterious mutations plays an important role in the evolution of breeding systems. These models make predictions regarding the relative rates of protein evolution and deleterious mutation in taxa with contrasting modes of reproduction. Here we compare available coding sequences from one obligately outcrossing and two primarily selfing species of Caenorhabditis to

A. D. Cutter; B. A. Payseur

2003-01-01

240

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

NASA Technical Reports Server (NTRS)

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.

1980-01-01

241

Ecological Footprint  

NSDL National Science Digital Library

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.

Education, Connecticut E.

242

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

PubMed

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 degrees 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

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

2007-06-19

243

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

USGS Publications Warehouse

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

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

2010-01-01

244

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

PubMed Central

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.

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

2010-01-01

245

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

PubMed Central

Vibrio fischeri is a bioluminescent bacterial symbiont of sepiolid squids (Cephalopoda: Sepiolidae) and monocentrid fishes (Actinopterygii: Monocentridae). V. fischeri exhibit competitive dominance within the allopatrically distributed squid genus Euprymna, which have led to the evolution of V. fischeri host specialists. In contrast, the host genus Sepiola contains sympatric species that is thought to have given rise to V. fischeri that have evolved as host generalists. Given that these ecological lifestyles may have a direct effect upon the growth spectrum and survival limits in contrasting environments, optimal growth ranges were obtained for numerous V. fischeri isolates from both free-living and host environments. Upper and lower limits of growth were observed in sodium chloride concentrations ranging from 0.0% to 9.0%. Sepiola symbiotic isolates possessed the least variation in growth throughout the entire salinity gradient, whereas isolates from Euprymna were the least uniform at <2.0% NaCl. V. fischeri fish symbionts (CG101 and MJ101) and all free-living strains were the most dissimilar at >5.0% NaCl. Growth kinetics of symbiotic V. fischeri strains were also measured under a range of salinity and temperature combinations. Symbiotic V. fischeri ES114 and ET101 exhibited a synergistic effect for salinity and temperature, where significant differences in growth rates due to salinity existed only at low temperatures. Thus, abiotic factors such as temperature and salinity have differential effects between free-living and symbiotic strains of V. fischeri, which may alter colonization efficiency prior to infection.

Soto, W.; Gutierrez, J.; Remmenga, M. D.; Nishiguchi, M. K.

2009-01-01

246

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

USGS Publications Warehouse

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.

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

2013-01-01

247

[Suppressive effect of plant secondary substances and ecological measures on Liriomyza sativae population].  

PubMed

A state-space population model was used to evaluate the effect of plant secondary substances and ecological measures on the population dynamics of the vegetable leafminer, Liriomyza sativae. In the vegetable field, by spraying alcohol extracts of Lantana camara (1 g.100 ml-1), or spraying the petroleum spray oil (300 x), or releasing the parasitoids, the indices of population control(IIPC) of L. sativae compared with control were 0.136, 0.222 and 0.292, respectively, but the index of population trend of vegetable leafminer in control was as high as 11.15, the population of vegetable leafminer still increased by control each one of the methods. Based on the state space analysis, the controlling effects of the alcohol extracts combining with other methods on vegetable leafminer were stimulated, which showed that the alcohol extracts from Lantana camara (1 g.100 ml-1) plus horticultural spray oils(300 x) used once at the period of adult summit, and the parasitoids released 1000 to 2000 per 100 m2 gave the index of population of vegetable leafminer below 1, means that vegetable leafminer would be controlled sustainably. PMID:14997652

Xian, Jidong; Liang, Guangwen; Zeng, Ling; Pang, Xiongfei

2003-11-01

248

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...

249

Aquatox (Release 2) Modeling Environmental Fate and Ecological Effects in Aquatic Ecosystems. Volume 2: Technical Documentation.  

National Technical Information Service (NTIS)

New approaches and tools, including appropriate technical guidance documents, are needed to facilitate ecosystem analyses of watersheds as required by the Clean Water Act. In particular, there is a pressing need for refinement and release of an ecological...

2004-01-01

250

AQUATOX (Release 2) Modeling Environmental Fate and Ecological Effects in Aquatic Ecosystems. Volume 1: User's Manual.  

National Technical Information Service (NTIS)

New approaches and tools, including appropriate technical guidance documents, are needed to facilitate ecosystem analyses of watersheds as required by the Clean Water Act. In particular, there is a pressing need for refinement and release of an ecological...

R. A. Park J. S. Clough M. C. Wellman

2004-01-01

251

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

PubMed

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

Camargo, Julio A; Alonso, Alvaro

2006-08-01

252

Framework for ecological risk assessment  

Microsoft Academic Search

Increased interest in ecological issues such as global climate change, habitat loss, acid deposition, reduced biological diversity, and the ecological impacts of pesticides and toxic chemicals prompts this U.S. Environmental Protection Agency (EPA) report, A Framework for Ecological Risk Assessment ('Framework Report'). The report describes basic elements, or a framework, for evaluating scientific information on the adverse effects of physical

D. Rodier; S. Norton; John H. Gentile; William H. van der Schalie; William P. Wood; Michael W. Slimak

1992-01-01

253

Metabolic ecology.  

PubMed

Ecological theory that is grounded in metabolic currencies and constraints offers the potential to link ecological outcomes to biophysical processes across multiple scales of organization. The metabolic theory of ecology (MTE) has emphasized the potential for metabolism to serve as a unified theory of ecology, while focusing primarily on the size and temperature dependence of whole-organism metabolic rates. Generalizing metabolic ecology requires extending beyond prediction and application of standardized metabolic rates to theory focused on how energy moves through ecological systems. A bibliometric and network analysis of recent metabolic ecology literature reveals a research network characterized by major clusters focused on MTE, foraging theory, bioenergetics, trophic status, and generalized patterns and predictions. This generalized research network, which we refer to as metabolic ecology, can be considered to include the scaling, temperature and stoichiometric models forming the core of MTE, as well as bioenergetic equations, foraging theory, life-history allocation models, consumer-resource equations, food web theory and energy-based macroecology models that are frequently employed in ecological literature. We conclude with six points we believe to be important to the advancement and integration of metabolic ecology, including nomination of a second fundamental equation, complementary to the first fundamental equation offered by the MTE. PMID:24028511

Humphries, Murray M; McCann, Kevin S

2014-01-01

254

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

NASA Astrophysics Data System (ADS)

During the last fifteen years a research team from School of Forestry at the Technical University of Madrid (Spain) has developed several competitive research projects regarding forest roads and open top culverts. A first approach was established with a prototype of 7 meters length in a hydraulic channel at the laboratory determining main parameters of different open top culverts in relation to different sizes of gravels and the self washing properties relationship with different slopes up to 8 %. The curves obtained may help to properly install these drainage systems avoiding maintenance costs. In addition more targeted pilot studies were developed in different forest earth roads in center and north Spain. The construction of the stations under study was financed by the U.P.M and the R&D National Plan. The main outcomes relates the low variation of humidity in a 20 m. wide range at both sides of the open top culverts and several considerations relating the angle of installation, the spacing of such drainage systems and the benefits against rilling along the roads. Also the erosion produced downhill was established and some construction methods to avoid adverse ecological effects. The diffusion of results includes congresses and a small booklet with a great acceptance in forestry services. Also a patent (ES 2 262 437) of an advanced model has been registered.

García, Jose L.; Elorrieta, Jose; Robredo, Jose C.; García, Ricardo; García, Fernando; Gimenez, Martin C.

2013-04-01

255

[Using chlorella and effective microorganisms to optimize aquatic ecological structure and to regulate water quality].  

PubMed

To optimize aquatic ecological structure and to regulate water quality, Chlorella vulgaris and effective microorganism were added to Exopalaemon carinicauda pond and fishponds. The results showed that after adding Chlorella vulgaris to the shrimp pond and fishpond, Chlorella vulgaris turned into a dominant species, and its amount was 16.92 and 4.76 times of CK. The zooplankton biomass reached to 4.32 mg.L-1 and 2.84 mg.L-1, increasing by 19.3% and 2.5%, compared with CK, respectively. Rhodospirillaceae, photosynthetic bacteria and yeast saccharomycete in the ponds could obviously change the composition, number, ratio, and biomass of the plankton (phytoplankton and zooplankton), and adjust aquatic chemical environment. The treatment of "Saccharomycete + Nitrifying bacteria" decreased the concentrations of NH4+ obviously, which was only 44% of CK. The BOD and COD in shrimp ponds were only 56.5% and 38.4% of CK. The treatment could increase the dissolved oxygen and primary production in the pond. PMID:12722449

Han, Shiqun; Zhang, Zhenhua; Yu, Lijun

2003-01-01

256

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

PubMed

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

Sanchez-Bayo, Francisco; Goka, Kouichi

2006-06-01

257

Effects of land use on concentrations of metals in surface soils and ecological risk around Guanting Reservoir, China.  

PubMed

It is accepted that the historical routine use of agrochemicals may have resulted in undesirable concentrations of metals in the environment. To investigate and assess the effects of land use on concentrations of heavy metals around the Guanting Reservoir in China, 52 surface soil samples (depth of 2-10 cm) were taken from areas where four types of land use were practiced (including arable land, woodland, bare land, orchard land). The metals and metalloids (As, Cr, Ni, Cu, Zn, Cd, and Pb) were analyzed using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Significant accumulation of As, Cd, and Cr was found in soils of arable land. Based on correlation and cluster analysis, it can be concluded that Cd and Zn originate mainly from phosphate fertilizer, Pb from the use of insecticides, fertilizers, and sewage sludge as well as air deposition, and Cu from copper-based fungicides, while As, Ni and Cr might come from parent soil material. According to an ecological risk analysis of metals based on the ecological index suggested by Hakanson, the four types of land can be ranked by severity of ecological risk as follows: arable land > woodland > bare land > orchard land, with a high ecological risk of Cd for all four types. Management measures for land use planners for avoiding water, soil, and sediment pollution caused by metals around the Guanting Reservoir are presented. PMID:17805979

Luo, Wei; Lu, Yonglong; Giesy, John P; Wang, Tieyu; Shi, Yajuan; Wang, Guang; Xing, Ying

2007-12-01

258

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

SciTech Connect

To elucidate ecological effects of variation in the temporal distribution of a limiting resource (water in the Mojave Desert), energetics of two free-living populations of desert tortoises (Gopherus [=Xerobates] agassizii) were studied concurrently over 18 mo with use of doubly-labeled water. Field metabolic rates (FMR) and feeding rates were highly variable. This variability was manifested at several levels, including seasonal changes within populations, year-to-year differences within populations, and differences between populations. Underlying observed patterns and contrasts was considerable variation among individuals. Much of the variation in energetic variables was associated with a single climatic variable, rainfall. Seasonal, annual, and interpopulation differences in FMR and foraging rates corresponded to differences in availability of free-standing water from rainstorms. Some differences among individuals were apparently due to differences in proclivity or ability to drink. Tortoises had very low FMRs relative to other reptiles, allowed them to tolerate long periods of chronic energy shortage during a drought. Calculations suggested that tortoises experienced a net loss of energy shortage during a drought and tortoises experienced a net loss of energy on their spring diet of succulent annual plants. If so, tortoises require drier forage to accrue an energy profit, emphasizing reliance on drinking rainwater. Further, it suggests that growth (as protein deposition) and net acquisition of energy may be temporally decoupled in desert tortoises, with potential consequences for geographic variation in life history. Energy acquisition and expenditure in desert tortoises are strongly constrained by the contingencies of rainfall, both indirectly through effects on availability and quality of food, and directly through reliance on free-standing water for drinking, which is apparently necessary for achieving a net annual energy profit. 61 refs., 5 figs., 5 tabs.

Peterson, C.C. [Univ. of California, Los Angeles, CA (United States)

1996-09-01

259

Anthills in School Ecology  

ERIC Educational Resources Information Center

Suggests experiments with field ants which can demonstrate the effect an organism has on its surroundings. The ecological aspects explored are plant distribution on the ant hills and the differences between ant hills and the undisturbed soil surrounding. (BR)

Pawson, J. Marke

1975-01-01

260

ECOLOGICAL FORECASTING FOR WATERSHEDS  

EPA Science Inventory

To effectively manage watersheds, the assessment of watershed ecological response to physicochemical stressors such as nutrients, sediments, pathogens, and toxics over broad spatial and temporal scales is needed. Assessments at this level of complexity requires the development of...

261

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...

262

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

PubMed

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

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

2013-11-01

263

Ecological Biology (Program Description)  

NSF Publications Database

... in the following areas. Ecology: Supports studies of community ecology and population interactions ... 7) co-evolution, and (8) chemical ecology. Ecology particularly encourages studies that reveal ...

264

Effect of nationwide injury prevention programme on serious spinal injuries in New Zealand rugby union: ecological study  

Microsoft Academic Search

Objective To investigate the effect of RugbySmart, a nationwide educational injury prevention programme, on the frequency of spinal cord injuries.Design Ecological study.Setting New Zealand rugby union. Participants Population at risk of injury comprised all New Zealand rugby union players. Intervention From 2001, all New Zealand rugby coaches and referees have been required to complete RugbySmart, which focuses on educating rugby

Kenneth L Quarrie; Simon M Gianotti; Will G Hopkins; Patria A Hume

2007-01-01

265

Social Support and Social-ecological Resources as Mediators of Lifestyle Intervention Effects for Type 2 Diabetes  

Microsoft Academic Search

A study was conducted to determine if an intervention could change social support and social-ecological resources of post-menopausal women diagnosed with type 2 diabetes, and if those changes mediated the intervention’s effects on health behaviors and outcomes. Women (N = 279) were randomly assigned to receive a comprehensive 6-month Mediterranean Lifestyle Program (MLP) or usual care from their physicians (UC).

Manuel Barrera; Deborah J. Toobert; Karyn L. Angell; Russell E. Glasgow; David P. Mackinnon

2006-01-01

266

Prediction of Deleterious Nonsynonymous Single-Nucleotide Polymorphism for Human Diseases  

PubMed Central

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

Jiang, Rui

2013-01-01

267

[Deleterious mutations in various Drosophila melanogaster strains carrying meiotic mutation c(3)G].  

PubMed

In the absence of meiotic recombination, deleterious mutations, decreasing the viability, are accumulated and fixed in small Drosophila populations. Study of the viability of hybrid progenies of three laboratory Drosophila melanogaster strains carrying meiotic mutation c(3)G17 has suggested that the deleterious mutations are negatively synergistic in their interaction. The deleterious mutations localized to the pericentromeric region of chromosome 3 are threefold more efficient as compared with the mutations located in distal regions. Substitution of a new chromosome for the balancer chromosome in a strain with meiotic mutation c(3)G17 partially restores (by approximately 20%) the viability of homozygotes c(3)G17/c(3)G17 over the first 20-30 generations. Further cultivation for 30 generations with the same balancer again decreases the viability to the initial level. An epigenetic nature of deleterious mutations is discussed. PMID:18846818

chubykin, V L

2008-09-01

268

Issues in Ecology, Issue 08: Effects of Aquaculture on World Fish Supply  

NSDL National Science Digital Library

This report discusses the negative and positive aspects of aquaculture as an alternative to harvesting wild stocks of fish. The report defines aquaculture and describes its recent growth, as well as its ecological impact. Practices to sustain aquaculture operations, such as habitat modification and the use of wild-caught seedstock are discussed. Changes to ocean food webs, the introduction of non-native fish and pathogens, and nutrient pollution from wastes are presented as negative consequences of aquaculture operations. The report discusses strategies to improve aquaculture, such as reducing fish meal and oil in fish feed, integrating production systems, and promoting sustainability within the industry. Issues in Ecology is an ongoing series of reports designed to present major ecological issues in an easy-to-read manner. This Issue summarizes the consensus of a panel of scientific experts based on the information that was current and available at the time of its publication in 2001.

Naylor, Rosamond

2010-02-16

269

The ecological effects of thermopeaking in Alpine streams in flume simulations  

NASA Astrophysics Data System (ADS)

In Alpine areas, the temporal patterns of hydropower plants operations can have consequences for the water bodies which receive downstream releases in the form of "hydropeaking", typically consisting in sharp releases of turbinated water in the river reaches below dams. Hydropeaking may significantly affect also the thermal regime of rivers: typically power plants fed by hypolimnetic releases from large dams cause a reduction in summer temperature and an increase in winter temperatures for long distances downstream. Very few studies have addressed the effects of the short-term temperature fluctuations related to hydropeaking (i.e., thermopeaking) on aquatic fauna, although they can be a major cause of riverine habitat degradation posing serious threats to aquatic communities. In the Adige River watershed, warm thermopeaking occurs from September to January and results in additional (up to 4°C) heating to the natural dial fluctuations; cold thermopeaking occurs from March to July and cools down the temperature (up to 6°C), in contrast with the natural trend that would result in heating during the day. The biological effects of thermopeaking are difficult to study in nature, because they are associated with hydropeaking, which is known to cause a high catastrophic drift due to the increased intensity of bed scour. However, controlled simulations of thermopeaking events could be performed in artificial flumes. We used artificial flumes which had proved to perform discharge manipulations which simulate hydropeaking events, and conducted four simulations, two warm thermopeakings in early and late winter, and two cold-thermopeakings, in early and late summer, respectively. The impact of thermopeaking on benthic macroinvertebrates was assessed by collecting those organisms which are displaced from the substrate and drift in the water column. Displacement can be active (i.e., part of the behavioural repertoire of certain insect species), or passive (i.e., catastrophic and generated by any disturbance). Drifting invertebrates were collected at time intervals before the simulation, and at continuous, short-time intervals during the simulation in order to follow the changes in drift over a short time period during the simulation. We assessed the effects of thermopreaking on the benthos community by answering to the following questions: 1) Do thermal alterations induce an increase in drift of benthic invertebrates? 3) Do a reduction or an increase in water temperature have different effects of invertebrate drift? Benthic invertebrates responded more to the cold thermopeaking simulations, with differences among taxa with different life strategies and ecological requirements.

Maiolini, Bruno; Carolli, Mauro; Bruno, M. Cristina; Siviglia, Annunziato

2010-05-01

270

Ecological Consultancy  

ERIC Educational Resources Information Center

This is the first of a new regular feature on careers, designed to provide those who teach biology with some inspiration when advising their students. In this issue, two consultant ecologists explain how their career paths developed. It is a misconception that there are few jobs in ecology. Over the past 20 or 30 years ecological consultancy has…

Wilson, Scott McG.; Tattersfield, Peter

2004-01-01

271

What's Ecology?  

ERIC Educational Resources Information Center

A brief statement of what ecology means in the 1970's, how we have upset our biosphere, and what are alternatives are, form the introduction in this booklet about ecology for upper elementary and senior high school students. The text and illustrations develop an overview of planet Earth as an interactive unit to establish a basis for understanding…

Humphrey, Clifford C.; Evans, Robert G.

272

Community metabolism of aquatic Closed Ecological Systems: Effects of nitrogen sources  

NASA Astrophysics Data System (ADS)

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.

Taub, Frieda B.

2009-10-01

273

Fate and ecological effects of decabromodiphenyl ether in a field lysimeter.  

PubMed

Flame-retardant polybrominated diphenyl ethers (PBDEs) are environmental contaminants. Deca-BDE is increasingly used commercially, but little is known about the long-term fate and impact of its major component, decabromodiphenyl ether (BDE-209), on the soil environment. In this study, we investigated the fate and ecological effect of BDE-209 over 4 years in outdoor lysimeters in a field planted with a rice-wheat rotation. BDE-209 and six lower-brominated PBDEs (BDE-28, -47, -99, -153, -154, and -183) were detected in soil layers of the test lysimeter. We calculated an average BDE-209 migration rate of 1.54 mg·m(-2)·yr(-1). In samples collected in May 2008, November 2008, November 2009, November 2010, and November 2011, 95.5%, 94.3%, 108.1%, 33.8%, and 35.5% of the spiked BDE-209 were recovered, respectively. We predicted the major pathway for debromination of BDE-209 in soil to be: BDE-209?BDE-183?BDE-153/BDE-154?BDE-99?BDE-47?BDE-28. In plants, BDE-209 and seven lower-brominated PBDEs (BDE-28, -47, -99, -100, -153, -154, and -183) were detected. BDE-100 was mainly derived from the debromination of BDE-154 in plants, but sources of other lower-brominated PBDEs were still difficult to determine. In soils containing BDE-209 for 4 years, soil urease activity increased, and soil protease activity slightly decreased. Our results provide important insights for understanding the behavior of BDE-209 in agricultural soils. PMID:23899302

Du, Wenchao; Ji, Rong; Sun, Yuanyuan; Zhu, Jianguo; Wu, Jichun; Guo, Hongyan

2013-08-20

274

Environmental effects on mineral accumulation in rice grains and identification of ecological specific QTLs.  

PubMed

Optimizing the beneficial mineral elements in rice grains is of interest for rice breeders. To study the environmental effects on mineral accumulation in rice grains, we grew a double-haploid (DH) population derived from the cross between cultivars Chunjiang 06 (CJ06, a japonica rice) and TN1 (an indica rice) under two different ecological environments (Lingshui and Hangzhou, China) and determined the content of Ca, Fe, K, Mg, Mn, P, and Zn in brown rice. These contents show transgressive variation among the DH lines. Subsequently, the quantitative trait loci (QTLs) for mineral accumulation in rice grain were mapped on the chromosomes using CJ06/TN1 population. For the 7 mineral elements investigated, 23 and 9 QTLs were identified for Lingshui and Hangzhou, respectively. Of these, 24 QTLs were reported for the first time in this study and 8 QTLs are consistent with previous reports. Only 2 QTLs for Mg accumulation have been detected in both environments, indicating that mineral accumulation QTLs in rice grains are largely environment dependent. Additionally, co-localizations of QTLs for Mn and Zn, Mg and P, and Mg and Mn accumulation have been observed, implying that these loci might be involved in the accumulation of different elements. Furthermore, the QTLs for the accumulation of Fe, K, Mg, Mn, P, and Zn were mapped to a region close to each other on chromosomes 8 and 9, suggesting that clusters of genes exist on chromosomes 8 and 9. Further characterization of these QTLs will provide a better understanding of the molecular mechanism responsible for mineral accumulation in rice grains. PMID:22760687

Du, Juan; Zeng, Dali; Wang, Biao; Qian, Qian; Zheng, Shusong; Ling, Hong-Qing

2013-04-01

275

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

PubMed

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

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

2005-09-01

276

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

PubMed Central

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.

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

2011-01-01

277

Effect of aridification on carbon isotopic variation and ecologic evolution at 5.3 Ma in the Asian interior  

NASA Astrophysics Data System (ADS)

The Cenozoic era is marked by dramatic climatic and ecological changes. The timing of the emergence and the subsequent expansions of C4 grasses are prominent biological events on Earth. In China, thick Cenozoic deposits in the Tarim and Junggar Basins, which are located in the Asian interior, provide important geological archives for studying paleoenvironmental changes. Here we use carbon isotope compositions of organic matter to reconstruct the history of ecologic evolution during the late Cenozoic in the Tarim and Junggar Basins. The results show that there is a shift to slightly higher ?13C values at 5.3 Ma indicating a change in terrestrial ecosystems in the Asian interior driven by an increased regional aridity rather than decreasing atmospheric pCO2 levels. The weakened water vapor transportation related to the retreat of Paratethys Ocean and the enhanced rain shadow effect of mountain uplift during the latest Miocene mostly triggered this event.

Sun, Jimin; Lü, Tongyan; Gong, Yingzeng; Liu, Weiguo; Wang, Xu; Gong, Zhijun

2013-10-01

278

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

PubMed Central

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.

Wang, Hui-Yu; Hook, Tomas O

2009-01-01

279

AQUATOX (Release 2) Modeling Environmental Fate and Ecological Effects in Aquatic Ecosystems. Volume 3: User's Manual for the Basins (Version 3.1) Extension to AQUATOX Release 2.  

National Technical Information Service (NTIS)

AQUATOX is a time-variable ecological risk assessment model that stimulates the fate and effects of various environmental stressors in aquatic ecosystems. It simulates the fate and transfer of pollutants from loads to the water, sediments, and biotic comp...

2004-01-01

280

Overall effect of rice biomass and fish on the aquatic ecology of experimental rice plots  

Microsoft Academic Search

The integration of rice and fish culture promises ecologically sound and economically successful management of floodwater ecosystems. Amongst other benefits, the stocking of fish in rice fields may contribute to the soil fertility of the rice field. We investigated the impact of the rice biomass and the stocking of fish (a polyculture of Nile tilapia and common carp) on ammonium,

Nico Vromant; Nguyen Thi Hoai Chau

2005-01-01

281

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...

282

Effects of human activities on the ecological changes of lakes in China  

Microsoft Academic Search

Lake ecosystems are greatly affected by anthropogenic activities due to population growth and the accompanying development of industry and agriculture. These anthropogenic activities include intensified exploitation of fisheries resources, reclamation of land from marshes of lakes, wastewater discharge, construction of water conservancy, and tourism etc. The negative ecological consequences in lakes caused by these factors are discussed in detail and

Z. S. Zhang; Z. P. Mei

1996-01-01

283

Mechanisms for Migration of Anadromous Herring: An Ecological Basis for Effective Conservation  

Microsoft Academic Search

Land use planners have the challenge of incorporating biologically sound guidelines into development plans to balance human development with conservation of natural resources. Valued as an important component of the natural heritage of the north- eastern United States, anadromous river herring (Alosa pseudoharengus, A. aestivalis) rep- resent a model system to look at how ecological data can help conserve biological

Lisa A. Yako; Martha E. Mather; Francis Juanes

2002-01-01

284

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...

285

An ecological dose-response model approach to short- and long-term effects of heavy metals on arylsulphatase activity in soil  

Microsoft Academic Search

The aim of this study was to provide data to evaluate the short- and long-term effects of heavy metals on arylsulphatase activity in five soils. The effects are fitted on a logistic dose-response model and are presented graphically as the ecological dose (heavy metal concentration corresponding to 50% inhibition; ED50) and ecological dose range (heavy metal concentration range corresponding to

L. Haanstra; P. Doelman

1991-01-01

286

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

PubMed

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

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

2012-10-01

287

Gestational Magnesium Deficiency Is Deleterious to Fetal Outcome  

Microsoft Academic Search

A number of recent epidemiological findings have implicated magnesium as being essential to fetal well-being. Few studies, however, have examined the relationship between maternal requirements for dietary magnesium and subsequent mortality and morbidity in offspring. The present study uses a rodent model of dietary-induced hypomagnesemia to investigate the effects of magnesium deficiency prior to and during gestation on neonatal morbidity

Rosalita A. Almonte; Deanne L. Heath; John Whitehall; Miranda J. Russell; Sanjay Patole; Robert Vink

1999-01-01

288

Examining the full effects of landscape heterogeneity on spatial genetic variation: a multiple matrix regression approach for quantifying geographic and ecological isolation.  

PubMed

Understanding the effects of landscape heterogeneity on spatial genetic variation is a primary goal of landscape genetics. Ecological and geographic variables can contribute to genetic structure through geographic isolation, in which geographic barriers and distances restrict gene flow, and ecological isolation, in which gene flow among populations inhabiting different environments is limited by selection against dispersers moving between them. Although methods have been developed to study geographic isolation in detail, ecological isolation has received much less attention, partly because disentangling the effects of these mechanisms is inherently difficult. Here, I describe a novel approach for quantifying the effects of geographic and ecological isolation using multiple matrix regression with randomization. I explored the parameter space over which this method is effective using a series of individual-based simulations and found that it accurately describes the effects of geographic and ecological isolation over a wide range of conditions. I also applied this method to a set of real-world datasets to show that ecological isolation is an often overlooked but important contributor to patterns of spatial genetic variation and to demonstrate how this analysis can provide new insights into how landscapes contribute to the evolution of genetic variation in nature. PMID:24299396

Wang, Ian J

2013-12-01

289

Ecological Effects of Sea Level Rise: Advancing coastal management through integrated research and engagement  

NASA Astrophysics Data System (ADS)

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.

Kidwell, D. M.

2012-12-01

290

The effects of ecological restoration on CO2 fluxes from a climatically marginal upland blanket bog  

NASA Astrophysics Data System (ADS)

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.

Dixon, Simon; Qassim, Suzane; Rowson, James; Worrall, Fred; Evans, Martin

2013-04-01

291

Effects of human activities on the ecological processes of river biofilms in a highly urbanized river  

NASA Astrophysics Data System (ADS)

Many anthropogenic disturbances and their effects of aquatic ecosystem are difficult to quantify in urbanized rivers. In past, specific taxa analysis of community structure was a common approach in river health monitoring studies. However, it is still difficult to understand stream ecosystem integrity without considering ecosystem processes. The complex species composition and metabolism of a river biofilm have the capacity to interact and/or modulate their surrounding environment. Because of their short life cycles, species richness, and worldwide distribution, structure and function of river biofilm communities are sensitive to change in environmental conditions. Therefore, biofilms are widely used as early warning systems of water pollution for water quality monitoring studies. In this study, we used river biofilms as a bioindicator by examining their extracellular enzyme activities and photosynthesis efficiency to understand human activities on the ecological processes of river ecosystem in a highly urbanized river. We sampled four sites along the Keelung River, Taiwan, based on different intensities of anthropogenic disturbances including water pollution index, population densities, land use types and types of stream habitats. Two study sites are heavily influenced by human activities and the others are not. The activities of extracellular enzymes within the biofilm play an important function for organic matter decomposition and nutrient cycling. We measured seven extracellular enzyme activities (?-d-glucosidase, phosphatase, leucine-aminopeptidase, sulfatase, peroxidase, polyphenol oxidase, and esterase) to examine specific enzyme activity changes at four study sites monthly. In addition, relative proportion of each extracellular enzyme activity on total enzyme activities was calculated in order to examine the relationship between functional biofilm profiles and different urban intensities. Among four study sites, leucine-aminopeptidase and esterase activities constituted nearly 50% of total enzyme activities. Peroxidase and polyphenol oxidase activities were about 30% of total enzyme activities. Some extracellular enzyme activities showed seasonal variation. For example, phosphatase, peroxidase, and polyphenol oxidase activities were higher in the summer than in the winter, whereas esterase activity was lower in the summer than in the winter. The algal and cyanobacterial assemblages of river biofilms provide the main site of primary productivity in river ecosystem. Through chlorophyll a fluorescence detection, we examined the efficiency of transformation energy in photosynthesis of river biofilms. Measurements of biofilm photosynthetic efficiency showed to be below the normal level of photosynthetic efficiency among four study sites. By combining these two aspects, we discussed how biofilms were affected by different anthropogenic disturbances and hope to contribute a better understanding of river ecosystem processes for river health monitoring program.

Hung, R.; Li, M.

2013-12-01

292

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.

293

Increasing Energetic Cost of Biosynthesis during Growth Makes Refeeding Deleterious.  

PubMed

Abstract Diet restriction (DR) enhances animals' health maintenance, but refeeding reverses its beneficial effects. However, to what degree refeeding reverses the beneficial effects of DR remains controversial. Here, I develop a theoretical model for reconciling the results of refeeding studies and understanding the dynamic and reversible mechanism underlying the effects of diet on health from the energetic viewpoint. By illustrating the negative correlation between health maintenance and the energetic cost of growth in animals under different diet regimes, the model explains why, in some cases, refed animals have better health and live longer than freely fed controls. More importantly, the model reveals that, in some species, the energetic cost of synthesizing biomass increases during growth, so the expensive compensatory growth induced by refeeding later in life offsets the benefits of the inexpensive retarded growth induced by diet restriction early in life. Thus, in these species, refeeding drives animals to allocate more energy to growth and less to maintenance and therefore leads to poor health status and shorter life span compared to freely fed controls. PMID:25058283

Hou, Chen

2014-08-01

294

Campus Ecology  

NSDL National Science Digital Library

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.

Federation, National W.

295

Serous Tubal Intraepithelial Carcinoma in a Japanese Woman with a Deleterious BRCA1 Mutation.  

PubMed

Risk-reducing salpingo-oophorectomy for reducing future cancer risk in women with hereditary breast and ovarian cancer syndrome is rarely performed in Japan; therefore, the cancer preventive effect of risk-reducing salpingo-oophorectomy for hereditary breast and ovarian cancer syndrome among the Japanese population remains unclear. Here, we report the first case of serous tubal intraepithelial carcinoma identified through a risk-reducing salpingo-oophorectomy in a Japanese woman with hereditary breast and ovarian cancer syndrome and who had a deleterious germline mutation of E1214X in BRCA1, but not a BRCA2 mutation. A pre-operative examination revealed multiple uterine leiomyomas but no adnexal mass. Robotic-assisted bilateral salpingo-oophorectomy together with hysterectomy was performed. A pathological examination identified serous tubal intraepithelial carcinoma in the right fallopian tube with no dissemination. Serous tubal intraepithelial carcinoma is implicated as an origin of invasive cancer of the fallopian tube with peritoneal dissemination; prophylactic salpingo-oophorectomy is currently the only method to identify this occult cancer. Our case demonstrated that risk-reducing salpingo-oophorectomy can detect occult cancers, including serous tubal intraepithelial carcinoma, thereby preventing future cancer development in the Japanese hereditary breast and ovarian cancer syndrome population. PMID:24719479

Ishikawa, Hiroshi; Kiyokawa, Takako; Utsuno, Emi; Matsushita, Kazuyuki; Nomura, Fumio; Shozu, Makio

2014-06-01

296

P2X7 receptors mediate deleterious renal epithelial-fibroblast cross talk.  

PubMed

Peritubular fibroblasts in the kidney are the major erythropoietin-producing cells and also contribute to renal repair following acute kidney injury (AKI). Although few fibroblasts were observed in the interstitium adjacent to damaged tubular epithelium in the early phase of AKI, the underlying mechanism by which their numbers were reduced remains unknown. In this study, we tested the hypothesis that damaged renal epithelial cells directly induce renal interstitial fibroblast death by releasing intracellular ATP and activating purinergic signaling. Exposure of a cultured rat renal interstitial fibroblast cell line (NRK-49F) to necrotic renal proximal tubular cells (RPTC) lysate or supernatant induced NRK-49F cell death by apoptosis and necrosis. Depletion of ATP with apyrase or inhibition of the P2X purinergic receptor with pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid blocked the deleterious effect of necrotic RPTC supernatant. The P2X7 receptor, an ATP-sensitive purinergic receptor, was not detected in cultured NRK-49F cells but was inducible by necrotic RPTC supernatant. Treatment with A438079, a highly selective P2X7 receptor inhibitor, or knockdown of the P2X7 receptor with small interference RNA diminished renal fibroblast death induced by necrotic RPTC supernatant. Conversely, overexpression of the P2X7 receptor potentiated this response. Collectively, these findings provide strong evidence that damaged renal epithelial cells can directly induce the death of renal interstitial fibroblasts by ATP activation of the P2X7 receptor. PMID:20861083

Ponnusamy, Murugavel; Ma, Li; Gong, Rujun; Pang, Maoyin; Chin, Y Eugene; Zhuang, Shougang

2011-01-01

297

Small insertions are more deleterious than small deletions in human genomes.  

PubMed

Although lines of evidence suggest that small insertions and deletions differ in their mechanisms of formation, there remains the debate on whether natural selection acts differently on the two indel types. Currently available personal genomes and the 1000 Genomes Project permit population level and genome scale comparison of the selection regimes on the two indel types. We first developed a statistical model to evaluate the indel frequency biases of the 1000 Genomes Project phase 1 data. We then identified four independent lines of evidence demonstrating that human small (1-4 bp) insertions are on average more deleterious than deletions. This genome-wide selection pattern is not affected by methodology, demography, and regional differences including indel density, introns versus exons, repeats versus nonrepeats, recombination rates, and the timing of DNA replication. This selection pattern has a profound effect on indel frequency spectra, deletional bias, and local single-nucleotide mutation rates. Finally, we observed that small insertions appear to be more actively implicated in shaping fast-evolving genomic sequences (or nonconserved regions). PMID:24000181

Huang, Shengfeng; Li, Jie; Xu, Anlong; Huang, Guangrui; You, Leiming

2013-12-01

298

Adapting to climate change on Western public lands: addressing the ecological effects of domestic, wild, and feral ungulates.  

PubMed

Climate change affects public land ecosystems and services throughout the American West and these effects are projected to intensify. Even if greenhouse gas emissions are reduced, adaptation strategies for public lands are needed to reduce anthropogenic stressors of terrestrial and aquatic ecosystems and to help native species and ecosystems survive in an altered environment. Historical and contemporary livestock production-the most widespread and long-running commercial use of public lands-can alter vegetation, soils, hydrology, and wildlife species composition and abundances in ways that exacerbate the effects of climate change on these resources. Excess abundance of native ungulates (e.g., deer or elk) and feral horses and burros add to these impacts. Although many of these consequences have been studied for decades, the ongoing and impending effects of ungulates in a changing climate require new management strategies for limiting their threats to the long-term supply of ecosystem services on public lands. Removing or reducing livestock across large areas of public land would alleviate a widely recognized and long-term stressor and make these lands less susceptible to the effects of climate change. Where livestock use continues, or where significant densities of wild or feral ungulates occur, management should carefully document the ecological, social, and economic consequences (both costs and benefits) to better ensure management that minimizes ungulate impacts to plant and animal communities, soils, and water resources. Reestablishing apex predators in large, contiguous areas of public land may help mitigate any adverse ecological effects of wild ungulates. PMID:23151970

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

299

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

Microsoft Academic Search

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

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

2003-01-01

300

The effects of the three gorges project on ecology and environment  

Microsoft Academic Search

The impacts of the Three Gorges Project are summarized in this paper from the viewpoint of the whole Changjiang (Yangtze)\\u000a River basin and system ecology. Among the impacts on aquatic ecosystem and fishery of the river basin, the emphasis is placed\\u000a on the survival of certain precious and rare species, such as the indigenous River Dolphin,Lipotes vexillifer. The impacts on

Yicheng Xia

1994-01-01

301

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

PubMed Central

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

2014-01-01

302

Effect of systematic empiric treatment with imipenem on the bacterial ecology in a burns unit.  

PubMed

This study took place over 18 months and was divided into three 6 month periods. During the first and third periods, the bacterial ecology of the unit was reviewed, including the observation of bacteria which were isolated and led us to prescribe general antimicrobial therapy, and record the subsequent antibiograms that became available. During the second 6 month period, any patient developing an infection due (or possibly due) to a "Gram negative" strain received imipenem (as beta lactam antimicrobial agent), usually combined with tobramycin. The comparison between bacteria and antibiograms isolated during the first and the third periods did not show any increase in multiple resistant bacteria or imipenem resistant strains, including methicillin resistant Staphylococcus aureus (MRSA). During the third period, in comparison with the first, the number of Pseudomonas aeruginosa and Acinetobacter strains was lower; however, the number of Enterobacter and Klebsiella had increased. There was an increase of overall resistance to ticarcillin, but there was no increase in resistance to the other antimicrobials concerned in the study. Therefore, we concluded that wide use of imipenem did not impair the bacterial ecology of the unit, if used with precautions such as high dose regimen, de-escalation, and both pharmacokinetics and ecology monitoring. PMID:16039784

Le Floch, Ronan; Arnould, Jean François; Pilorget, Alain

2005-11-01

303

The Effect of Social and Classroom Ecological Factors on Promoting Self-Determination in Elementary School  

PubMed Central

Promoting the self-determination of students with disabilities as a means to access the general curriculum has been the subject of research in recent years, as has the importance of efforts to promote self-determination during elementary years. To examine the status of such efforts in the field, 203 elementary special educators were surveyed in 23 states to determine how (a) classroom instructional practices or strategies, (b) classroom ecological or setting variables, and (c) self-reported barriers to promoting self-determination affected their perceptions of the importance of teaching self-determination and the frequency with which they did so. Results indicated that special educators’ perceived importance of teaching self-determination was not impacted by classroom instructional factors, but was affected by classroom ecological factors. Classroom ecological factors were not, however, significant in the frequency with which teachers provided instruction on self-determination, but classroom instructional practices were. Limitations and implications are discussed, and suggestions for future research are offered.

Cho, Hyunjeong; Wehmeyer, Michael; Kingston, Neil

2014-01-01

304

Geomorphic and ecological effects of Hurricanes Katrina and Rita on coastal Louisiana marsh communities  

USGS Publications Warehouse

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

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

305

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

306

Overview of the effects of the coal fuel cycle on hydrology, water quality and use, and aquatic ecology  

SciTech Connect

Literature is summarized for the effects of the coal fuel cycle (mining, mine-site processing, transportation, storage, onsite processing, combustion, and waste collection and disposal) on water resources. Aspects considered include surface- and ground-water hydrology, water quality and use, and aquatic ecology. Water use is discussed with regard to both availability and water quality constraints on use. Requirements of the recently enacted Surface Mining Control and Reclamation Act are introduced where appropriate. For the combustion step in the fuel cycle, only those effects which are specific to coal as a fuel are addressed. Effects not specific to coal use (such as thermal effects, impingement, and entrainment resulting from cooling water withdrawal and use) are not considered. Reference is made to more exhaustive studies of the topics reviewed. A summary of the major environmental effects of the coal fuel cycle is given below.

Cushman, R.M.; Gough, S.B.; Moran, M.S.

1980-05-01

307

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

PubMed

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

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

2014-06-01

308

Reduced selection and accumulation of deleterious mutations in genes exclusively expressed in men.  

PubMed

Sex-limited selection can moderate the elimination of deleterious mutations from the population and contribute to the high prevalence of common human diseases. Accordingly, deleterious mutations in autosomal genes that are exclusively expressed in only one of the sexes undergo sex-limited selection and can reach higher frequencies than mutations similarly selected in both sexes. Here we show that the number of deleterious SNPs in genes exclusively expressed in men is twofold higher than in genes that are selected in both sexes. Additional analyses suggest that the increased number of damaging mutations we found in male-specific genes is due to reduced selection in females. These results are noteworthy since many of these male-specific genes are known to be crucial for male reproduction, and are thus likely to be under strong purifying selection. We suggest that inheritance of male-infertility-causative mutations through unaffected female lineages contributes to the high incidence of male infertility. PMID:25014762

Gershoni, Moran; Pietrokovski, Shmuel

2014-01-01

309

Two classes of deleterious recessive alleles in a natural population of zebrafish, Danio rerio.  

PubMed Central

Natural populations carry deleterious recessive alleles which cause inbreeding depression. We compared mortality and growth of inbred and outbred zebrafish, Danio rerio, between 6 and 48 days of age. Grandparents of the studied fish were caught in the wild. Inbred fish were generated by brother-sister mating. Mortality was 9% in outbred fish, and 42% in inbred fish, which implies at least 3.6 lethal equivalents of deleterious recessive alleles per zygote. There was no significant inbreeding depression in the growth, perhaps because the surviving inbred fish lived under less crowded conditions. In contrast to alleles that cause embryonic and early larval mortality in the same population, alleles responsible for late larval and early juvenile mortality did not result in any gross morphological abnormalities. Thus, deleterious recessive alleles that segregate in a wild zebrafish population belong to two sharply distinct classes: early-acting, morphologically overt, unconditional lethals; and later-acting, morphologically cryptic, and presumably milder alleles.

McCune, Amy R.; Houle, David; McMillan, Kyle; Annable, Rebecca; Kondrashov, Alexey S.

2004-01-01

310

Ecological effects on streams from forest fertilization; literature review and conceptual framework for future study in the western Cascades  

USGS Publications Warehouse

Fertilization of forests with urea-nitrogen has been studied numerous times for its effects on water quality. Stream nitrogen concentrations following fertilization are typically elevated during winter, including peaks in the tens-of-thousands of parts per billion range, with summer concentrations often returning to background or near-background levels. Despite these increases, water-quality criteria for nitrogen have rarely been exceeded. However, such criteria are targeted at fish toxicity or human health and are not relevant to concentrations that could cause ecological disturbances.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.

Anderson, C. W.

2002-01-01

311

Workshop on Closed System Ecology  

NASA Technical Reports Server (NTRS)

Self maintaining laboratory scale ecological systems completely isolated from exchanges of matter with external systems were demonstrated. These research tools are discussed in terms of their anticipated value in understanding (1) global ecological material and energy balances, (2) the dynamics of stability and instability in ecosystems, (3) the effects of man-made substances and structures on ecosystems, and (4) the precise requirements for dynamic control of controlled ecology life support systems (CELSS).

1982-01-01

312

Association between Protective and Deleterious HLA Alleles with Multiple Sclerosis in Central East Sardinia  

PubMed Central

The human leukocyte antigen (HLA) complex on chromosome 6p21 has been unambiguously associated with multiple sclerosis (MS). The complex features of the HLA region, especially its high genic content, extreme polymorphism, and extensive linkage disequilibrium, has prevented to resolve the nature of HLA association in MS. We performed a family based association study on the isolated population of the Nuoro province (Sardinia) to clarify the role of HLA genes in MS. The main stage of our study involved an analysis of the ancestral haplotypes A2Cw7B58DR2DQ1 and A30Cw5B18DR3DQ2. On the basis of a multiplicative model, the effect of the first haplotype is protective with an odds ratio (OR)?=?0.27 (95% confidence interval CI 0.13–0.57), while that of the second is deleterious, OR 1.78 (95% CI 1.26–2.50). We found both class I (A, Cw, B) and class II (DR, DQ) loci to have an effect on MS susceptibility, but we saw that they act independently from each other. We also performed an exploratory analysis on a set of 796 SNPs in the same HLA region. Our study supports the claim that Class I and Class II loci act independently on MS susceptibility and this has a biological explanation. Also, the analysis of SNPs suggests that there are other HLA genes involved in MS, but replication is needed. This opens up new perspective on the study of MS.

Pastorino, Roberta; Menni, Cristina; Barca, Monserrata; Foco, Luisa; Saddi, Valeria; Gazzaniga, Giovanna; Ferrai, Raffaela; Mascaretti, Luca; Dudbridge, Frank; Berzuini, Carlo; Murgia, Salvatore Bruno; Piras, Maria Luisa; Ticca, Anna; Bitti, Pier Paolo; Bernardinelli, Luisa

2009-01-01

313

Migration intensity has no effect on peak HIV prevalence: an ecological study  

PubMed Central

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.

2014-01-01

314

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

PubMed

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

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

2014-08-01

315

A synthesis of the ecological effects of air pollution from nitrogen and sulfur in the U.S  

USGS Publications Warehouse

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.

Greaver, T. L.; Sullivan, T.; Herrick, J. D.; Barber, M.; Baron, J.; Cosby, B.; Deerharke, M.; Dennis, R.; Dubois, J. J. D.; Goodale, C.; Herlihy, A.; Lawrence, G.; Liu, L.; Lynch, J.; Novak, K.

2012-01-01

316

Prediction of Deleterious Non-Synonymous SNPs Based on Protein Interaction Network and Hybrid Properties  

Microsoft Academic Search

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.

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

2010-01-01

317

Ecological risk assessment. Book chapter  

SciTech Connect

Risk assessment has been suggested as a tool to help manage ecological problems. Ecological risk assessment is usually defined as the process that evaluates the likelihood that adverse ecological effects are occurring, or may occur, as a result of exposure to one or more stressors. The basic concept, while straightforward, is difficult to apply to any but the simplest ecological problems. A formidable problem in many risk assessments, and especially for complex questions such as addressing the challenge of ecological sustainability, is selecting what ecological component or system is to be considered at risk. This selection is entirely social and political, but estimating the actual risk is technical and scientific. The question of what is at risk must be answered within the political decision-making framework or the results of the risk assessment will be of limited utility.

Lackey, R.T.

1996-03-01

318

Restoration Ecology  

NSDL National Science Digital Library

While not a panacea, the emerging field of restoration ecology provides an important tool for environmental conservation and contributes greatly to our understanding of ecology.The first Web site is the home page of the Society for Ecological Restoration, offering a good starting point for exploring this relatively new discipline (1). The next site (2) provides an overview of the University of Wisconsin's Center for Restoration Ecology, "the first comprehensive, interdisciplinary research team assembled to advance the science and technology of ecosystem restoration." The National Oceanic and Atmospheric Administration outlines its plans for coastal and estuarine restoration in this Web site (3). The Fermi National Accelerator Laboratory in Illinois has implemented one of the largest tallgrass prairie restorations to date (4). The Kissimmee River Restoration Web site (5) provides a detailed look at this incredibly ambitious dam removal and wetland restoration project in Florida. The next Web site (6) offers a visually-attractive introduction to the restoration efforts of the nonprofit organization RESTORE, focusing on the forests of Maine. The Wildlands Project, another restoration-oriented nonprofit organization, describes its vision of ecosystem conservation in this Web site, which includes a personal brief from distinguished biologist E. O. Wilson. (7). The Wildwood project of the Scottish organization Carrifran offers an interesting contrast to restoration efforts in the US, as much of Scotland has been denuded of its original forests for thousands of years (8).

Sohmer, Rachel.

2002-01-01

319

Trash Ecology  

ERIC Educational Resources Information Center

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

Lind, Georgia J.

2004-01-01

320

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

PubMed Central

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

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

2013-01-01

321

[Ecological effect of hygroscopic and condensate water on biological soil crusts in Shapotou region of China].  

PubMed

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

Pan, Yan-Xia; Wang, Xin-Ping; Zhang, Ya-Feng; Hu, Rui

2013-03-01

322

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

PubMed

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

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

2012-08-27

323

Effects of environmental change on zoonotic disease risk: an ecological primer.  

PubMed

Impacts of environmental changes on zoonotic disease risk are the subject of speculation, but lack a coherent framework for understanding environmental drivers of pathogen transmission from animal hosts to humans. We review how environmental factors affect the distributions of zoonotic agents and their transmission to humans, exploring the roles they play in zoonotic systems. We demonstrate the importance of capturing the distributional ecology of any species involved in pathogen transmission, defining the environmental conditions required, and the projection of that niche onto geography. We further review how environmental changes may alter the dispersal behaviour of populations of any component of zoonotic disease systems. Such changes can modify relative importance of different host species for pathogens, modifying contact rates with humans. PMID:24636356

Estrada-Peña, Agustín; Ostfeld, Richard S; Peterson, A Townsend; Poulin, Robert; de la Fuente, José

2014-04-01

324

Quantifying the effect of ecological restoration on soil erosion in China's Loess Plateau region: an application of the MMF approach.  

PubMed

Land degradation due to erosion is one of the most serious environmental problems in China. To reduce land degradation, the government has taken a number of conservation and restoration measures, including the Sloping Land Conversion Program (SLCP), which was launched in 1999. A logical question is whether these measures have reduced soil erosion at the regional level. The objective of this article is to answer this question by assessing soil erosion dynamics in the Zuli River basin in the Loess Plateau of China from 1999 to 2006. The MMF (Morgan, Morgan and Finney) model was used to simulate changes in runoff and soil erosion over the period of time during which ecological restoration projects were implemented. Some model variables were derived from remotely sensed images to provide improved land surface representation. With an overall accuracy rate of 0.67, our simulations show that increased ground vegetation cover, especially in forestlands and grasslands, has reduced soil erosion by 38.8% on average from 1999 to 2006. During the same time period, however, the change in rainfall pattern has caused a 13.1% +/- 4.3% increase in soil erosion, resulting in a net 25.7% +/- 8.5% reduction in soil erosion. This suggests that China's various ecological restoration efforts have been effective in reducing soil loss. PMID:19756858

Li, Changbin; Qi, Jiaguo; Feng, Zhaodong; Yin, Runsheng; Guo, Biyun; Zhang, Feng; Zou, Songbing

2010-03-01

325

Using reproductive and developmental effects data in ecological risk assessments for oviparous vertebrates exposed to contaminants. Review draft  

SciTech Connect

Ecological Risk Assessment (ERA) is a tool often used to support risk-based decision-making. An essential step in the process of applying reproductive and developmental effects data within a risk assessment context is developing an understanding of how the information is relevant to the risk-based policy question at hand. This chapter addresses how reproductive and development effects data from studies of contaminants can be used by ERA. The authors also discuss how a number of important policy, technical, and procedural topics are addressed in the course of framing and implementing the risk assessment. One of the authors` objectives is to determine if the current ERA paradigm needs modifications to address unique risks of contaminants to oviparous vertebrates. A secondary objective is to provide information on ERA procedures to toxicologists, physiologists, ecologists, chemists, and modelers who are knowledgeable about oviparous vertebrates, illuminating how the results of their disciplines may be used in this area.

Clark, J.R.; Dickson, K.L.; Giesy, J.P.; Lackey, R.T.; Mihaich, E.M.

1998-09-21

326

Modeling Between- and Within-Subject Variance in Ecological Momentary Assessment (EMA) Data Using Mixed-Effects Location Scale Models  

PubMed Central

Ecological Momentary Assessment (EMA) and/or Experience Sampling (ESM) methods are increasingly used in health studies to study subjective experiences within changing environmental contexts. In these studies, up to thirty or forty observations are often obtained for each subject. Because there are so many measurements per subject, one can characterize a subject’s mean and variance, and specify models for both. 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 statistical 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. 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.

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

2013-01-01

327

Strontium ranelate prevents the deleterious action of advanced glycation endproducts on osteoblastic cells via calcium channel activation.  

PubMed

Accumulation of advanced glycation endproducts (AGEs) in bone tissue occurs in ageing and in Diabetes mellitus, and is partly responsible for the increased risk of low-stress bone fractures observed in these conditions. In this study we evaluated whether the anti-osteoporotic agent strontium ranelate can prevent the deleterious effects of AGEs on bone cells, and possible mechanisms of action involved. Using mouse MC3T3E1 osteoblastic cells in culture we evaluated the effects of 0.1mM strontium ranelate and/or 100 ?g/ml AGEs-modified bovine serum albumin (AGEs-BSA) on cell proliferation, osteogenic differentiation and pro-inflammatory cytokine production. We found that AGEs-BSA alone decreased osteoblastic proliferation and differentiation (P<0.01) while increasing IL-1? and TNF? production (P<0.01). On its own, strontium ranelate induced opposite effects: an increase in osteoblast proliferation and differentiation (P<0.01) and a decrease in cytokine secretion (P<0.01). Additionally, strontium ranelate prevented the inhibitory and pro-inflammatory actions of AGEs-BSA on osteoblastic cells (P<0.01). These effects of strontium ranelate were blocked by co-incubation with either the MAPK inhibitor PD98059, or the calcium channel blocker nifedipine. We also evaluated by Western blotting the activation status of ERK (a MAPK) and b-catenin. Activation of both signaling pathways was decreased by AGEs treatment, and this inhibitory effect was prevented if AGEs were co-incubated with strontium ranelate (P<0.01). On its own, strontium ranelate increased both pERK and activated b-catenin levels. In conclusion, this study demonstrates that strontium ranelate can prevent the deleterious in vitro actions of AGEs on osteoblastic cells in culture by mechanisms that involve calcium channel, MAPK and b-catenin activation. PMID:23499695

Fernández, Juan Manuel; Molinuevo, María Silvina; Sedlinsky, Claudia; Schurman, León; Cortizo, Ana María; McCarthy, Antonio Desmond

2013-04-15

328

Functional Molecular Ecological Networks  

PubMed Central

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

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

2010-01-01

329

[A review on road ecology].  

PubMed

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

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

2003-03-01

330

Family Wellness: An Ecological Perspective.  

ERIC Educational Resources Information Center

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…

Fannin, Ronald A.

331

INTEGRATED MODELING AND ECOLOGICAL VALUATION  

Microsoft Academic Search

1. OBJECTIVES Understanding how anthropogenic and climate-induced changes alter ecological systems and evaluating the effects of alternative hydrologic profiles on these ecosystems are important concerns in the semi-arid West. The goal of the proposed research is to incorporate hydrologic, vegetation, avian, and economic models into an integrated framework to determine the value of changes in ecological systems that result from

David S. Brookshire; Bonnie Colby; David Goodrich; John Loomis; Holly Richter; Steven Stewart

332

Effective Management of Ocean Biogeochemistry and Ecological Data: the BCO-DMO Story  

NASA Astrophysics Data System (ADS)

Data availability expectations of the research community, environmental management decision makers, and funding agency representatives are changing. Consequently, data management practices in many science communities are changing as well. In an effort to improve access to data generated by ocean biogeochemistry and ecological researchers funded by the United States (US) National Science Foundation (NSF) Division of Ocean Sciences (OCE), the Biological and Chemical Oceanography Data Management Office (BCO-DMO) was created in late 2006. Currently, the main BCO-DMO objective is to ensure availability of data resulting from select OCE and Office of Polar Programs (OPP) research awards granted by the US NSF. An important requirement for the BCO-DMO data management system is that it provides open access to data that are supported by sufficient metadata to enable data discovery and accurate reuse. The office manages and serves all types of oceanographic data (in situ, experimental, model results) generated during the research process and contributed by the originating investigators from large national programs and medium-sized collaborative research projects, as well as researchers with single investigator awards. BCO-DMO staff members have made strategic use of standards and use of terms from controlled vocabularies while balancing the need to maintain flexible data ingest systems that accommodate the heterogeneous nature of ocean biogeochemistry and ecological research data. Many of the discrete ocean biogeochemistry data sets managed by BCO-DMO are still acquired manually, often with prototype sensor systems. Data sets such as these that are not "born-digital" present a significant management challenge. Use of multiple levels of term-mappings and development of an ontology has enabled BCO-DMO to incorporate a semantically enabled faceted search into the data access system that will improve data access through enhanced data discovery. BCO-DMO involves an ongoing collaboration between data managers and marine scientists funded by the US NSF. BCO-DMO staff members work with investigators throughout the data life cycle, beginning with the data management plan that is part of the original proposal, during cruise planning and experimental design, through data reporting to meet funding agency requirements and finally to submission of final data sets for publication and final archive in a permanent data center. It is important to note that support from and continued active involvement of the NSF program managers has been a significant contributor to the success of this developing system. URL: http://bco-dmo.org/

Chandler, C. L.; Groman, R. C.; Allison, M. D.; Wiebe, P. H.; Glover, D. M.; Gegg, S. R.

2012-04-01

333

Animal Ecology  

NSDL National Science Digital Library

This tutorial introduces students to the concept of animal ecology. The first section explains the different ways animals use camouflage. There is also a discussion of how the process of decay breaks organic matter down into nutrients, and how simple aquatic organisms (algae, zooplankton) provide a food source for larger organisms. The concept of food chains is introduced, and land-based and aquatic examples are described. A quiz and glossary are included.

334

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

PubMed

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

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

2014-09-15

335

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 Red Phosphorus-Butyl Rubber and White Phosphorus Obscurant Smokes: Final Report.  

National Technical Information Service (NTIS)

An evaluation of the terrestrial transport, transformations and ecological effects of phosphorus (red phosphorus-butyl rubber (RP/BR)) smoke obscurant was performed at Pacific Northwest Laboratory. A similar evaluation using white phosphorus (WP) smoke/ob...

P. Van Voris M. W. Ligotke K. M. McFadden S. M. W. Li B. L. Thomas

1987-01-01

336

Ecological implications of anti-pathogen effects of tropical fungal endophytes and mycorrhizae.  

PubMed

We discuss studies of foliar endophytic fungi (FEF) and arbuscular mycorrhizal fungi (AMF) associated with Theobroma cacao in Panama. Direct, experimentally controlled comparisons of endophyte free (E-) and endophyte containing (E+) plant tissues in T. cacao show that foliar endophytes (FEF) that commonly occur in healthy host leaves enhance host defenses against foliar damage due to the pathogen (Phytophthora palmivora). Similarly, root inoculations with commonly occurring AMF also reduce foliar damage due to the same pathogen. These results suggest that endophytic fungi can play a potentially important mutualistic role by augmenting host defensive responses against pathogens. There are two broad classes of potential mechanisms by which endophytes could contribute to host protection: (1) inducing or increasing the expression of intrinsic host defense mechanisms and (2) providing additional sources of defense, extrinsic to those of the host (e.g., endophyte-based chemical antibiosis). The degree to which either of these mechanisms predominates holds distinct consequences for the evolutionary ecology of host-endophyte-pathogen relationships. More generally, the growing recognition that plants are composed of a mosaic of plant and fungal tissues holds a series of implications for the study of plant defense, physiology, and genetics. PMID:17503581

Herre, Edward Allen; Mejía, Luis C; Kyllo, Damond A; Rojas, Enith; Maynard, Zuleyka; Butler, Andre; Van Bael, Sunshine A

2007-03-01

337

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

PubMed

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. PMID:24628394

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

2014-08-01

338

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

SciTech Connect

Lack of aspen (Populus tremuloides) recruitment and canopy replacement of aspen stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado has been a cause of concern for more than 70 years (Packard, 1942; Olmsted, 1979; Stevens, 1980; Hess, 1993; R.J. Monello, T.L. Johnson, and R.G. Wright, Rocky Mountain National Park, 2006, written commun.). These aspen stands are a significant resource since they are located close to the park's road system and thus are highly visible to park visitors. Aspen communities are integral to the ecological structure of montane and subalpine landscapes because they contain high native species richness of plants, birds, and butterflies (Chong and others, 2001; Simonson and others, 2001; Chong and Stohlgren, 2007). These low-elevation, winter range stands also represent a unique component of the park's plant community diversity since most (more than 95 percent) of the park's aspen stands grow in coniferous forest, often on sheltered slopes and at higher elevations, while these winter range stands are situated on the low-elevation ecotone between the winter range grasslands and some of the park's drier coniferous forests.

Tuskan, Gerald A [ORNL; Yin, Tongming [ORNL

2008-10-01

339

Ecological Study of the Effects of Nuclear Power Plants on Benthic Macroplant Microcosms in Subtropical and Tropical Estuaries. Annual Progress Report, 1974--1975.  

National Technical Information Service (NTIS)

Progress is reported on the following research projects: the dynamic ecology of Thalassia and studies of the Thalassia community; basic ecology of Thalassia growth and reproduction; red macroalgal ecology; green macroalgal ecology; transplantation of Thal...

A. Thorhaug

1975-01-01

340

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

PubMed

Mitochondria constitute the major energy-producing compartment of the eukaryotic cell. These organelles contain many molecules of DNA that contribute only a handful of proteins required for energy production. Mutations in the DNA of mitochondria were identified as a cause of human disease a quarter of a century ago, and they have subsequently been implicated in ageing. The process whereby deleterious variants come to dominate a cell, tissue or human is the subject of debate. It is likely to involve multiple, often competing, factors, as selection pressures on mitochondrial DNA can be both indirect and intermittent, and are subjected to rapid change. Here, we assess the different models and the prospects for preventing the accumulation of deleterious mitochondrial DNA variants with time. PMID:24864317

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

2014-07-01

341

The Landscape Ecology of Invasive Spread  

Microsoft Academic Search

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,

2002-01-01

342

Minimising the risk of deleterious alkali-silica reaction in Irish concrete practice  

Microsoft Academic Search

National guidance on minimising the risk of alkali-silica reaction was first published in the Republic of Ireland in 1991. The introduction to practice of European Standard EN206-1 and the pending withdrawal of conflicting national standards prompted a review. This has recently concluded and revised national guidance on minimising the risk of deleterious reaction was proposed. The review focussed on recent

Mark Richardson

2005-01-01

343

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

PubMed

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

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

344

Somatic deleterious mutation rate in a woody plant: estimation from phenotypic data.  

PubMed

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

Bobiwash, K; Schultz, S T; Schoen, D J

2013-10-01

345

Aquatic predicted no-effect concentration for three polycyclic aromatic hydrocarbons and probabilistic ecological risk assessment in Liaodong Bay of the Bohai Sea, China.  

PubMed

Predicted no-effect concentration (PNEC) is often used in ecological risk assessment to determine low-risk concentrations for chemicals. In the present study, native marine species were selected for toxicity testing. The PNECs for three polycyclic aromatic hydrocarbons (PAHs), specifically phenanthrene (Phe), pyrene (Pyr), and benzo[a]pyrene (BaP), were derived from chronic and acute toxicity data with log-normal statistical methods. The achieved PNECs for Phe, Pyr, and BaP were 2.33, 1.09, and 0.011 ?g/L, respectively. In Jinzhou Bay and the Shuangtaizi River Estuary of Liaodong Bay in the Bohai Sea, China, the surface water concentrations of the three PAHs were analyzed by gas chromatography-mass spectrometry. Based on two probabilistic ecological risk assessment (PERA) methods, namely probabilistic risk quotient and joint probability curve, the potential risk of Phe, Pyr, and BaP in Jinzhou Bay and Shuangtaizi River Estuary was assessed. The same order of ecological risk (BaP > Phe > Pyr) was found by both models. Our study considered regional characteristics of marine biota during the calculation of PNECs, and the PERA methods provided probabilities of potential ecological risks of chemicals. Within the study area, further research on BaP is required due to its high potential ecological risk. PMID:23608972

Wang, Ying; Wang, Juying; Mu, Jingli; Wang, Zhen; Yao, Ziwei; Lin, Zhongsheng

2014-01-01

346

The Ecological Effects of Young Elm Trees Belt-Pumpkin Strip Intercropping System at the Agro-Pastoral Ecotone in Northern China  

Microsoft Academic Search

Young elm trees belt-pumpkin strip intercropping was studied to solve the actual problem of resource losses in the large barren area resulted from reconverting cultivated land into forest in the agro-pastoral ecotone in northern China. The final objective was to realize effective utilization of the barren land with both ecological improvement and economic development. Field experiments were conducted together with

Xiong DU; Tie-ling DOU; Li-xiao FENG; Wei-hong ZHANG; Li-feng ZHANG

2010-01-01

347

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

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…

Erdogan, Mehmet

2011-01-01

348

An Ecological Risk Assessment Framework for Effects of Onsite Wastewater Treatment Systems and Other Localized Sources of Nutrients on Aquatic Ecosystems  

Microsoft Academic Search

An ecological risk assessment framework for onsite wastewater treatment systems and other localized sources of nutrients is presented, including problem formulation, characterization of exposure, characterization of effects, and risk characterization. The framework is most pertinent to the spatial scale of residential treatment systems located adjacent to small ponds, streams, or lagoons and some parts of shallow estuaries. Freshwater and estuarine

Rebecca A. Efroymson; Daniel S. Jones; Arthur J. Gold

2007-01-01

349

Perception of screening and risk-reduction surgeries in patients tested for a BRCA deleterious mutation  

PubMed Central

Background Women at a high risk for breast cancer are offered choices for screening or prophylactic surgeries. Our aim was to evaluate opinions regarding screening and surgical strategies in high-risk women. Methods Women at our institution who received BRCA 1/2 testing before July 2005 were sent a follow-up patient survey. We compared responses of women who tested positive for a deleterious mutation with those who tested negative. Of those that expressed an opinion (agree vs. disagree), we used a 2-sided Fisher's Exact test to compare responses. Results A total of 540 surveys were sent and 312 were returned (58%). Of these, 217 had breast cancer and 86 women tested positive for a mutation. No BRCA + women felt mammograms were difficult to get due to discomfort while 5.4% of the BRCA - group did (p=.039). Seventy percent of BRCA + women agreed that prophylactic mastectomy (PM) is the most effective means for reducing risk, compared to 40% of BRCA - women (p<.001). PM was felt to be the only way to reduce worry in 64.7% of BRCA +, and in 34.4% of BRCA - women (p<.001). PM was felt to be too drastic for 36.1% of BRCA + and 40.5% of BRCA - women (p=.562). Difficulty in deciding between screening and PM occurred in 23.9% of BRCA + and 12.5% of BRCA - women (p=.046). After excluding women with bilateral breast cancers, 81.0% of women who agreed that PM was best to reduce risk underwent a PM vs. 19.1% of those who disagreed (p<.001). Of women who felt PM was the only way to reduce worry, 84.2% underwent PM. Only 15.8% of women who did not feel that it was the only way to decrease worry underwent PM (p<.001). Conclusions BRCA mutation carriers were more likely to believe PMs were the best way to reduce both risk and worry of breast cancer. High-risk women who agreed that PM was more likely to reduce risk and worry of breast cancer were more likely to proceed with this intervention.

Westin, S.N.; Ready, K.; Sun, C.C.; Peterson, S.K.; Meric-Bernstam, F.; Gonzalez-Angulo, A.M.; Bodurka, D.C; Lu, K.H.; Hortobagyi, G.N.; Arun, B.K.

2009-01-01

350

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.

351

Migration Ecology  

NSDL National Science Digital Library

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.

Alerstam, Thomas

2008-01-15

352

Industrial ecology.  

PubMed

Industrial ecology addresses issues that will impact future production, use, and disposal technologies; proper use of the concept should reduce significantly the resources devoted to potential remediation in the future. This cradle-to-reincarnation production philosophy includes industrial processes that are environmentally sound and products that are environmentally safe during use and economically recyclable after use without adverse impact on the environment or on the net cost to society. This will require an industry-university-government round table to set the strategy and agenda for progress. PMID:11607254

Patel, C K

1992-02-01

353

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

USGS Publications Warehouse

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.

Wirth, Troy A.; Pyke, David A.

2011-01-01

354

Mercury: Aspects of its ecology and environmental toxicity. [physiological effects of mercury compound contamination of environment  

NASA Technical Reports Server (NTRS)

A study was conducted to determine the effects of mercury pollution on the environment. The possible sources of mercury contamination in sea water are identified. The effects of mercury on food sources, as represented by swordfish, are analyzed. The physiological effects of varying concentrations of mercury are reported. Emphasis is placed on the situation existing in the Hawaiian Islands.

Siegel, S. M.

1973-01-01

355

The ecology of sexual conflict: background mortality can modulate the effects of male manipulation on female fitness.  

PubMed

Sexual and parental conflicts can arise because males benefit by inducing elevated reproductive effort in their mates. For females, the costs of such manipulation are often manifested later in life, and may therefore covary with female life expectancy. Here, I outline a simple female life-history model where female life expectancy reflects extrinsic mortality rate, and elevated reproductive effort causes accelerated senescence. Using this model, I show that variation in extrinsic mortality rate can modulate the magnitude and sign of fitness effects that male manipulation has on females. This result has several interesting implications. First, it suggests that the fitness effects of sexual interactions can depend on ecological factors, such as predation, that influence life expectancy. Second, if mortality risk is condition-dependent but reproductive effort is not fully optimized in relation to individual condition, then sexual conflict intensity may increase with individual condition, selecting for condition-dependent reproductive strategies. Third, if males vary in manipulativeness, then the fitness effects of mating with a given male phenotype may depend on both female condition and extrinsic mortality rate. Fourth, life span extension in the laboratory can lead to overestimation of sexual and parental conflicts. Life expectancy may therefore be a key factor in sexual coevolution. PMID:24102073

Bonduriansky, Russell

2014-02-01

356

Ecological Economics  

NASA Astrophysics Data System (ADS)

Taking as its starting point the interdependence of the economy and the natural environment, this book provides a comprehensive introduction to the emerging field of ecological economics. The authors, who have written extensively on the economics of sustainability, build on insights from both mainstream economics and ecological sciences. Part I explores the interdependence of the modern economy and its environment, while Part II focuses mainly on the economy and on economics. Part III looks at how national governments set policy targets and the instruments used to pursue those targets. Part IV examines international trade and institutions, and two major global threats to sustainability - climate change and biodiversity loss. Assuming no prior knowledge of economics, this textbook is well suited for use on interdisciplinary environmental science and management courses. It has extensive student-friendly features including discussion questions and exercises, keyword highlighting, real-world illustrations, further reading and website addresses. A comprehensive introduction to a developing field which will interest students from science, economics and management backgrounds A global approach to the problems of sustainability and sustainable development, issues which are increasingly prominent in political debate and policy making Filled with student-friendly features including focus areas for each chapter, keyword highlighting, real-world illustrations, discussion questions and exercises, further reading and website addresses

Common, Michael; Stagl, Sigrid

2005-10-01

357

A meta-analysis on the ecological effects of aquaculture on the water column: dissolved nutrients.  

PubMed

Environmental effects of aquaculture loadings have often been reviewed descriptively, and thus have not provided quantitative estimates of the overall response in the water column. Meta-analytical reviewing techniques allow the contextualisation of quantitative effects in the domain of current literature. In the present paper, more than 50 peer-reviewed articles were analysed and about 425 study cases used to test whether worldwide cultivations have a differential effect on dissolved nutrient levels. Meta-analysis feasibility depends on obtaining an estimate of the effect size from every study and the most common measure of effect size (Hedges' d) is the difference between means of controls and impacts standardised by dividing by the pooled standard deviation. Across all study cases, irrespective of cultivation and organism type, the cumulative effect size was large and significant (d>0.8) for ammonium, nitrite and nitrate, medium (0.8>d>0.5) for dissolved phosphorus, and not significant (d<0.2) for silicates. Effects were mainly correlated with the degree of openness in water bodies, and ammonium and the other nitrogen forms were the most highly informative descriptors of effects in the area surrounding farms, even though weakness in statistical approach was highlighted. The results partially contradict the common view that effects of aquaculture and associated environmental patterns are well defined throughout the current literature. PMID:17166578

Sarà, G

2007-05-01

358

Ecological resistance to the invasion of a freshwater clam, Corbicula fluminea : fish predation effects  

Microsoft Academic Search

Fish predation is shown to have a twenty nine fold effect on the abundance of the invasive freshwater clam, Corbicula fluminea, in a Texas reservoir. This predation has prevented the clam from establishing the high densities commonly reported for it elsewhere. The high magnitude of the fish effect is attributed to Corbicula being an invader to this reservoir and not

James V. Robinson; Gary A. Wellborn

1988-01-01

359

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

Microsoft Academic Search

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

Keith R. Hayes

2002-01-01

360

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

PubMed Central

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.

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

2009-01-01

361

Effects of ecological factors on secondary metabolites and inorganic elements of Scutellaria baicalensis and analysis of geoherblism.  

PubMed

This study analyzed the effects of ecological factors on secondary metabolites of Scutellaria baicalensis using two sources: 92 individual roots of S. baicalensis from all over China, and secondary metabolites, medicinal materials and inorganic element contents obtained from the testing of 92 S. baicalensis rhizosphere soil samples. The study used environmental data from the Genuine Medicinal Material Spatial Analysis Database. Most of the chemical constituents of S. baicalensis were negatively correlated to latitude and positively correlated to temperature; generally, the contents of 21 chemical constituents were higher at low latitudes than that at high latitudes. By gradual regression analysis, it was found that the content of baicalin in S. baicalensis was negatively correlated to latitude and generally the content of inorganic elements in soil was excessively high (excluding Mg and Ca), which has a negative effect on the accumulation of chemical constituents in S. baicalensis. Based on the cluster analysis of 21 constituents, S. baicalensis from different places of origin was divided into two groups, and S. baicalensis was not genuine only in a specific small region. Within the zone from Chifeng, Inner Mongolia to Taibai, Shaanxi is suitable for accumulation of secondary metabolites of S. baicalensis and such a zone represents a suitable distribution and potential genuine producing area. PMID:24203454

Guo, Lanping; Wang, Sheng; Zhang, Ji; Yang, Guang; Zhao, Manxi; Ma, Weifeng; Zhang, Xiaobo; Li, Xuan; Han, Bangxing; Chen, Naifu; Huang, Luqi

2013-11-01

362

Review article. Studying climate effects on ecology through the use of climate indices: the North Atlantic Oscillation, El Ni?o Southern Oscillation and beyond.  

PubMed Central

Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet.

Stenseth, Nils Chr; Ottersen, Geir; Hurrell, James W; Mysterud, Atle; Lima, Mauricio; Chan, Kung-Sik; Yoccoz, Nigel G; Adlandsvik, Bj?rn

2003-01-01

363

The use of invertebrate body burdens to predict ecological effects of metal mixtures in mining-impacted waters.  

PubMed

The present study investigated whether invertebrate body burdens can be used to predict metal-induced effects on aquatic invertebrate communities. Total dissolved metal levels and four invertebrate taxa (Leuctra sp., Simuliidae, Rhithrogena sp. and Perlodidae) were sampled in 36 headwater streams located in the north-west part of England. Using the River Invertebrate Prediction and Classification System (RIVPACS) taxonomic completeness of invertebrate communities was assessed. Quantile regression was used to relate invertebrate body burdens to a maximum (90th quantile) ecological response, both for all metals separately and in mixtures. Significant relations between Cu, Zn and Pb burdens in Leuctra sp. (Zn, Pb), Simuliidae (Zn, Pb), Rhithrogena sp. (Cu, Zn, Cu+Zn) and Perlodidae (Zn) and both taxonomic completeness (O/E taxa) and Biological Monitoring Working Party index scores (O/E BMWP) were observed. Correspondingly the obtained Cu-Zn mixture model an acceptable impact of 5% change in taxonomic completeness is expected at Rhithrogena sp. body burdens of 1.9?molg(-1) Cu (121 ?g g(-1) Cu) in case of low Zn bioavailability (Rhithrogena sp. Zn body burden of 2.9 ?mol g(-1) or 190 ?g g(-1)), which will drop to 0.30 ?mol g(-1) Cu (19.1 ?g g(-1) Cu) in case of higher Zn bioavailability (Zn body burden of 72.6 ?mol g(-1) or 4747 ?g g(-1)). For Zn, 5% change in taxonomic completeness is expected at Rhithrogena sp. body burdens of 76.4 ?mol g(-1) Zn (4995 ?g g(-1) Zn) in case of low Cu bioavailability (Cu body burden of 0.19 ?mol g(-1) or 12.1 ?g g(-1)), which will drop to 6.6 ?mol g(-1) Zn (432 ?g g(-1) Zn) at higher Cu bioavailability (Cu body burden of 1.74 ?mol g(-1) or 111 ?g g(-1)). Overall, the present study concludes that invertebrate body burdens can be used to (1) predict metal-induced ecological effects and (2) to derive critical burdens for the protection of aquatic invertebrate communities. PMID:24076621

De Jonge, Maarten; Tipping, Edward; Lofts, Stephen; Bervoets, Lieven; Blust, Ronny

2013-10-15

364

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

PubMed Central

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.

Yokoya, Masana; Shimizu, Hideyasu; Higuchi, Yukito

2012-01-01

365

The acute and chronic effects of wastes associated with offshore oil and gas production on temperate and tropical marine ecological processes  

Microsoft Academic Search

A review of the acute and chronic effects of produced formation water (PFW), drilling fluids (muds) including oil-based cutting muds, water-based cutting muds, ester-based cutting muds and chemical additives, and crude oils associated with offshore oil and gas production was undertaken in relation to both temperate and tropical marine ecological processes. The main environmental effects are summarized, often in tabular

Douglas A Holdway

2002-01-01

366

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

PubMed Central

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.

Preeprem, Thanawadee; Gibson, Greg

2014-01-01

367

Rare deleterious mutations of the gene EFR3A in autism spectrum disorders  

PubMed Central

Background Whole-exome sequencing studies in autism spectrum disorder (ASD) have identified de novo mutations in novel candidate genes, including the synaptic gene Eighty-five Requiring 3A (EFR3A). EFR3A is a critical component of a protein complex required for the synthesis of the phosphoinositide PtdIns4P, which has a variety of functions at the neural synapse. We hypothesized that deleterious mutations in EFR3A would be significantly associated with ASD. Methods We conducted a large case/control association study by deep resequencing and analysis of whole-exome data for coding and splice site variants in EFR3A. We determined the potential impact of these variants on protein structure and function by a variety of conservation measures and analysis of the Saccharomyces cerevisiae Efr3 crystal structure. We also analyzed the expression pattern of EFR3A in human brain tissue. Results Rare nonsynonymous mutations in EFR3A were more common among cases (16 / 2,196?=?0.73%) than matched controls (12 / 3,389?=?0.35%) and were statistically more common at conserved nucleotides based on an experiment-wide significance threshold (P?=?0.0077, permutation test). Crystal structure analysis revealed that mutations likely to be deleterious were also statistically more common in cases than controls (P?=?0.017, Fisher exact test). Furthermore, EFR3A is expressed in cortical neurons, including pyramidal neurons, during human fetal brain development in a pattern consistent with ASD-related genes, and it is strongly co-expressed (P?deleterious mutations in EFR3A were found to be associated with ASD using an experiment-wide significance threshold. Synaptic phosphoinositide metabolism has been strongly implicated in syndromic forms of ASD. These data for EFR3A strengthen the evidence for the involvement of this pathway in idiopathic autism.

2014-01-01

368

Bottom-up effects of geologic parent material through ecological interaction webs  

NASA Astrophysics Data System (ADS)

Community ecologists study the interactions between species to understand what controls the distribution and abundance of different populations. Communities are thus portrayed as "interaction webs", in which different species exert reciprocal pressures on each other. In the case of one population being a resource for which another population is the consumer (i.e. food-web), reciprocal pressures are commonly referred to as "bottom-up" vs. "top-down" effects. The starting point for studying bottom-up effects is usually the vegetation (primary producers), and its end-point the decomposer community responsible for breaking down detrital matter from each trophic level. In my presentation, I will present results from three former graduate students, to argue that the starting point for studying bottom-up effects should be the geologic parent material (GPM), whose importance has often been overlooked by community ecologists. For example, our data show that GPM had a stronger effect on forest floor nutrient budgets than the identity or successional stage of the vegetation. Likewise, GPM had a strong effect on the structure of forest floor microbial communities, as well as their resistance to, and resilience from, disturbance. GPM also had a significant effect on the richness and diversity of understory plant communities from similar forest stands. Finally, we present evidence that soil fertility controls the resistance and tolerance of certain plant species to selective browsing, thereby affecting the composition of the dominant plant cover and the feeding patterns of large herbivores.

Bradley, R.

2012-04-01

369

Leukemia Ecology: Ecological Prophylaxis of Leukemia.  

National Technical Information Service (NTIS)

Contents: Etiopathogenesis of leukemia; Ecological leukemogenic factors; Epidemiology of leukemias; Geochemical environment in relationship to health and disease; Leukemia risk factor bank; Perspectives of leukemia prophylaxis by ecological and dietary me...

J. Aleksandrowica A. B. Skotnicki

1982-01-01

370

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 ...

371

Effective Planning and Implementation of Ecological Rehabilitation Projects: A Case Study of the Regional Municipality of Waterloo (Ontario, Canada)  

Microsoft Academic Search

The literature guides environmental planning and, specifically, how to use ecological rehabilitation projects to achieve long-term\\u000a planning goals and landscape-scale environmental sustainability. There is, however, a perceived gap between principles in\\u000a the literature and the use of them by practitioners involved in smaller-scale ecological rehabilitation projects. Using interviews\\u000a with practitioners involved in 11 projects within the Regional Municipality of Waterloo,

SOONYA P. Quon; LARRY R. G. MARTIN; STEPHEN D. MURPHY

2001-01-01

372

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

NASA Astrophysics Data System (ADS)

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.

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

2012-08-01

373

Cost Effectiveness of Vegetative Filter Strips and Instream Half-logs for Ecological Restoration  

NASA Astrophysics Data System (ADS)

This paper presents the results of cost effectiveness (CE) analysis of vegetative filter strips (VFS) and instream half-logs as tools for recovering scores on a fish Index of Biotic Integrity (IBI) in the upper Wabash River watershed (UW) in Indiana. Three assumptions were made about recovery time for IBI scores (5, 15, and 30 years) and social discount rates (1, 3, and 5 percent), which were tested for sensitivity of the estimated CE ratios. Effectiveness of VFS was estimated using fish IBIs and riparian forest cover from 49 first-order to fifth-order stream reaches. Half-log structures had been installed for approximately two years in the UW prior to the study and provided a basis for estimates of cost and maintenance. Cost effectiveness ratios for VFS decreased from 387 to 277 per 100 m for a 1 percent increase in IBI scores from first- to fifthorder streams with 3 percent discount and 30-year recovery. This cost weighted by proportion of stream orders was $360. The ratio decreased with decreasing time of recovery and discount rate. Based on installation costs and an assumption of equal recovery rates, half-logs were two-thirds to one-half as cost-effective as VFS. Half-logs would be a cost-effective supplement to VFS in low order streams if they can be proven to recover IBI scores faster than VFS do. This study provides baseline data and a framework for planning and determining the cost of stream restoration.

Frimpong, Emmanuel A.; Lee, John G.; Sutton, Trent M.

2006-10-01

374

Roads and traffic: effects on ecology and wildlife habitat use; applications for cooperative adaptive management  

USGS Publications Warehouse

The land of the United States in dissected by more than 4 million miles of roads that fragment wildlife habitat on both public and private lands. Traffic on these roads causes additional effects. On secondary roads, which provide access to the most natural habitat, the levels, timing, and types of traffic are seldom known. In order to understand the effects of traffic on wildlife, USGS is conducting research cooperatively with the Bureau of Land Management, the U.S. Forest Service, the National Park Service, and the Colorado Division of Wildlifea?|

Ouren, Douglas S.; Watts, Raymond D.

2005-01-01

375

Association Between Loci With Deleterious Alleles and Distorted Sex Ratios in an Inbred Line of Tilapia (Oreochromis aureus)  

Microsoft Academic Search

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 (Or- eochromis aureus). The three markers were mapped previously to different linkage groups and were shown to be associated with genes with deleterious alleles in this

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

2002-01-01

376

One step beyond lethal equivalents: characterization of deleterious loci in the rapid cycling Brassica rapa L. base population  

Microsoft Academic Search

The total number of lethal equivalents as defined by Morton, Crow and Muller (1956) is a function of three parameters: M,\\u000a the number of loci at which deleterious mutations can occur, q, the frequency of the deleterious alleles at each locus, and\\u000a s, their selective value. A new approach based on multi?generation inbreeding data is outlined and used to infer

Martin Lascoux; Jae Kyun Lee

1998-01-01

377

Effect of shear on performance and microbial ecology of continuously stirred anaerobic digesters treating animal manure  

Microsoft Academic Search

We determined the effect of different mixing intensities on the performance, methanogenic population dynamics, and juxtaposition of syntrophic microbes in anaerobic digesters treating cow manure from a dairy farm. Computer automated radioactive particle tracking in con- junction with computational fluid dynamics was performed to quantify the shear levels locally. Four continuously stirred anaerobic digesters were operated at different mixing inten-

Rebecca A. Hoffmann; Marcelo L. Garcia; Mehul Veskivar; Khursheed Karim; Muthanna H. Al-Dahhan; Largus T. Angenent

2008-01-01

378

Fire and grazing in a shrub-invaded arid grassland community: independent or interactive ecological effects?  

Microsoft Academic Search

This study examined the response of summer and winter annuals and perennials in a shrub-invaded arid plant community to combinations of fire and grazing by cattle to determine their effects on individual abundances, species richness and diversity. Thirteen species differed significantly in abundance across the burn treatment while nine differed significantly across the grazing treatment. Summer and winter annual plants

Thomas J. Valone; Douglas A. Kelt

1999-01-01

379

Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis  

Microsoft Academic Search

This paper reviews and evaluates the current state of knowledge on the direct effects of terrestrial runoff on (1) the growth and survival of hard coral colonies, (2) coral reproduction and recruitment, and (3) organisms that interact with coral populations (coralline algae, bioeroders, macroalgae and heterotrophic filter feeders as space competitors, pathogens, and coral predators). The responses of each of

Katharina E. Fabricius

2005-01-01

380

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...

381

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...

382

Biological and ecological effects of wastewater discharges from cruise ships in Alaska  

Microsoft Academic Search

A Science Advisory Panel of the Alaska Cruise Ship Initiative investigated possible effects of commercial passenger vessel wastewater discharges on marine life in coastal waters of the Gulf of Alaska. The Panel concluded that due to the high dilution rates of moving cruise ships there is little likelihood of contaminant impacts to marine life in the water column, at the

A. Mearns; C. J. B. Krause; M. Stekoll; K. Hall; M. Watson; M. Atkinson

2003-01-01

383

Adverse Outcome Pathways and Ecological Risk Assessment: Bridging to Population Level Effects  

EPA Science Inventory

The viability of populations of plants and animals is a key focus for environmental regulation. Population-level responses integrate the cumulative effects of chemical stressors on individuals as those individuals interact with and are affected by their con-specifics, competitor...

384

Adverse Outcome Pathways and Ecological Risk Assessment: Bridging to Population Level Effects, Journal Article  

EPA Science Inventory

The viability of populations of plants and animals is a key focus for environmental regulation. Population-level responses integrate the cumulative effects of chemical stressors on individuals as those individuals interact with and are affected by their con-specifics, competitor...

385

Ecological effects of density-independent mortality: application to cooling-water withdrawals.  

PubMed

A wide variety of environmental stresses can cause density-independent mortality in species populations. One example is cooling-water withdrawals, which kill or injure many aquatic organisms near power plants and other industrial facilities. In the United States alone, hundreds of facilities withdraw trillions of gallons from inland and coastal waters every year to cool turbines and other manufacturing equipment. A number of detailed, site-specific studies of the effects of such cooling-water withdrawals have been conducted over the last 30 years, but only a few generalizations have been proposed in the peer-reviewed literature. In this paper we use a series of basic theoretical models to investigate the potential effects of density-independent mortality on species populations and ecosystems, with particular focus on the effects of cooling-water withdrawals on fish populations, fisheries, and aquatic communities. Among other results, we show that the effects of cooling-water withdrawals on a species will depend on the magnitude of other co-occurring stressors, environmental variability, the nature of the management regime in the associated fisheries, and the position of the species in the food web. The general models in this paper can provide a starting point for further empirical case studies and some preliminary conceptual guidance for decision makers who must choose between alternative policy options for controlling cooling-water withdrawals. PMID:17489247

Newbold, Stephen C; Iovanna, Rich

2007-03-01

386

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

SciTech Connect

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.

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

387

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

USGS Publications Warehouse

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.

Peck, Robert; Banko, Paul; Pendleton, Frank

2014-01-01

388

Ecological effects of cell-level processes: genome size, functional traits and regional abundance of herbaceous plant species  

PubMed Central

Background and Aims Genome size is known to be correlated with a number of phenotypic traits associated with cell sizes and cell-division rates. Genome size was therefore used as a proxy for them in order to assess how common plant traits such as height, specific leaf area and seed size/number predict species regional abundance. In this study it is hypothesized that if there is residual correlation between genome size and abundance after these traits are partialled out, there must be additional ecological effects of cell size and/or cell-division rate. Methods Variation in genome size, plant traits and regional abundance were examined in 436 herbaceous species of central European flora, and relationships were sought for among these variables by correlation and path analysis. Key Results Species regional abundance was weakly but significantly correlated with genome size; the relationship was stronger for annuals (R2 = 0·145) than for perennials (R2 = 0·027). In annuals, genome size was linked to abundance via its effect on seed size, which constrains seed number and hence population growth rate. In perennials, it weakly affected (via height and specific leaf area) competitive ability. These relationships did not change qualitatively after phylogenetic correction. In both annuals and perennials there was an unresolved effect of genome size on abundance. Conclusions The findings indicate that additional predictors of regional abundance should be sought among variables that are linked to cell size and cell-division rate. Signals of these cell-level processes remain identifiable even at the landscape scale, and show deep differences between perennials and annuals. Plant population biology could thus possibly benefit from more systematic use of indicators of cell-level processes.

Herben, Tomas; Suda, Jan; Klimesova, Jitka; Mihulka, Stanislav; Riha, Pavel; Simova, Irena

2012-01-01

389

A three-level mixed-effects location scale model with an application to ecological momentary assessment data.  

PubMed

In studies using ecological momentary assessment (EMA), or other intensive longitudinal data collection methods, interest frequently centers on changes in the variances, both within-subjects and between-subjects. For this, Hedeker et al. (Biometrics 2008; 64: 627-634) developed an extended two-level mixed-effects model that treats observations as being nested within subjects and allows covariates to influence both the within-subjects and between-subjects variance, beyond their influence on means. However, in EMA studies, subjects often provide many responses within and across days. To account for the possible systematic day-to-day variation, we developed a more flexible three-level mixed-effects location scale model that treats observations within days within subjects, and allows covariates to influence the variance at the subject, day, and observation level (over and above their usual effects on means) using a log-linear representation throughout. We provide details of a maximum likelihood solution and demonstrate how SAS PROC NLMIXED can be used to achieve maximum likelihood estimates in an alternative parameterization of our proposed three-level model. The accuracy of this approach using NLMIXED was verified by a series of simulation studies. Data from an adolescent mood study using EMA were analyzed to demonstrate this approach. The analyses clearly show the benefit of the proposed three-level model over the existing two-level approach. The proposed model has useful applications in many studies with three-level structures where interest centers on the joint modeling of the mean and variance structure. PMID:22865663

Li, Xue; Hedeker, Donald

2012-11-20

390

Group report: Physiological and ecological effects of acidification on aquatic biota (Chapter 19). Book chapter  

SciTech Connect

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. Mechanisms of effect are both direct (toxic responses to changes in chemistry) and indirect (e.g., expressed through the food chain or caused by changes in habitat), and the responses may be immediate or delayed. In turn, many biological processes, especially microbial processes, can influence surface water acid-base chemistry. Thus, chemical and biological changes are intricately linked and complex, with extensive feedbacks. Research on the effects of acid deposition and acidification on aquatic biota has been ongoing in Europe and North America for over the last 15 years, and many comprehensive reviews have been published. These gaps often have occurred because funding has focused on chemical mechanisms and modeling response of systems rather than in making resource inventories or resolving uncertainties in biological responses to acidification.

Baker, J.P.; Boehmer, J.; Hartmann, A.; Havas, M.; Jenkins, A.

1994-01-01

391

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

NSDL National Science Digital Library

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 SocietyÃÂs 2007 Frontiers in Physiology Program. For more information on this program, please visit www.frontiersinphys.org.

Norman Leonard (Pike High School)

2007-08-01

392

Effect of heavy metal pollution on mycorrhizal colonization and function: physiological, ecological and applied aspects  

Microsoft Academic Search

High concentrations of heavy metals in soil have an adverse effect on micro-organisms and microbial processes. Among soil\\u000a microorganisms, mycorrhizal fungi are the only ones providing a direct link between soil and roots, and can therefore be of\\u000a great importance in heavy metal availability and toxicity to plants. This review discusses various aspects of the interactions\\u000a between heavy metals and

C. Leyval; K. Turnau; K. Haselwandter

1997-01-01

393

Intratetrad mating, heterozygosity, and the maintenance of deleterious alleles in Microbotryum violaceum (=Ustilago violacea).  

PubMed

The mating system of Microbotryum violaceum was investigated in populations that are polymorphic for mating-type bias, where individuals produce viable haploids of only one of the two required mating types. The cause of mating-type bias was identified as deleterious recessive alleles linked to mating type. Maintenance of the deleterious alleles was promoted by early conjugation among products of single meioses, such that the duration of the free-living haploid stage is minimized. This development was also observed in nonbiased isolates. As a consequence, the mating system tends toward mating within the tetrad, which might be expected to reduce heterozygosity. However, complete centromere linkage of mating type ensures conjugation between first division meiotic products, such that mating in M. violaceum is analogous to forms of meiotic parthenogenesis with first division restitution (i.e. automixis with central fusion). This fungus was used to test the prediction that this mating system would maintain heterozygosity in regions of the genome linked to centromeres. Therefore, populations were screened for additional heterozygous lethal recessive alleles linked to centromeres, and several examples were found. Furthermore, the occurrence of intratetrad mating in M. violaceum provides an explanation for low variation among individuals within populations, inconsistent estimates of outcrossing rates, low levels of mating between tetrads of one diploid individual, and high frequencies of haplo-lethal alleles in natural populations. PMID:11012726

Hood, M E; Antonovics, J

2000-09-01

394

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

PubMed

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

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

2008-05-01

395

Sexual selection accelerates the elimination of a deleterious mutant in Drosophila melanogaster.  

PubMed

Although theory indicates that indirect genetic benefits through mate choice should be widespread, empirical work has often either failed to detect the operation of such benefits or shown a net cost to the presence of sexual selection. We tested whether sexual selection can increase the speed with which a conditionally deleterious allele is removed from a laboratory population of Drosophila melanogaster. The alcohol dehydrogenase null allele (Adh-) confers slightly lower viability than wild-type alleles in the absence of ethanol but is lethal in homozygotes when ethanol comprises 6% of the medium. We tracked the frequency of this allele in artificially constructed populations reared at three different levels of ethanol (0%, 2%, and 4%) that either experienced sexual selection or did not. Loss of the deleterious Adh- allele was more rapid when sexual selection was allowed to act, especially in the presence of ethanol. We also quantified the strength of both nonsexual and sexual selection against the Adh- allele using maximum-likelihood estimation. In contrast to recent experiments employing monogamy/polygamy designs, our results demonstrate a fitness benefit to sexual selection. This is consistent with the operation of good-genes female choice. PMID:19154371

Hollis, Brian; Fierst, Janna L; Houle, David

2009-02-01

396

Effect of different pollutants on ecologically important polychaete worms. Final report  

SciTech Connect

The procedures for culturing marine polychaetous annelids from egg to egg under laboratory conditions were described. A manual was prepared detailing the procedures used in culturing 12 species of polychaetes. The effects of heavy metals and the water soluble fractions of petroleum hydrocarbons were measured over 96 hours, 28 days, and with some of the toxicants, over a complete reproductive cycle for some of these species of polychaetes. Mercury and copper were the most toxic of the six metals tested and cadmium was the least toxic. The 28-day LC50 was less than the 96-hour value in most experiments.

Reish, D.J.

1980-06-01

397

An overview of dredging operations in the Chesapeake Bay. [environment effects and coastal ecology  

NASA Technical Reports Server (NTRS)

Maintenance of the Baltimore and the Newport News/Norfolk harbors as well as of the Chesapeake and Delaware Canal is accomplished by different dredging operations which depend on the amount and type of material to be moved, water depth, and location of disposal sites. Methods for determining the physical or chemical-biological interactive effects of these activities on the environment and on the shellfish and finfish industries on the Bay are discussed. The types of dredges used are classed according to their mode of operation.

Silver, R. H.

1978-01-01

398

Ecology Project  

NSDL National Science Digital Library

This project each student will research a biome that is found in North and Central America. They will create a detailed portfolio on this biome. Then they will research a zoo and how zoo\\'s act as a habitat for each of their animals. Once completed they will make a section of the zoo for their biome. Ecology Project Project Outline Biome Summary Earth Floor: Biome List of each Biome Individual Biome Resource NASA view of the BIOMES The World s Biomes World Biome You will need to make a climograph which includes average temperature and average precipitation. How to read a climograph For Section 2 Zoo Animal Planet Columbus Zoo & Aquarium Minnesota Zoo: Animals San Diego Zoo Kid Territory Smithsonian National Zoological Park: Animal Photo Galleries Woodland Park Zoo: Multimedia Zoos : A Historical Perspective : Smithsonian Institution Libraries On Display This will be a month long project. The overall project will include three sections. Section 1: Each student will conduct an extensive multimedia research project of the six biomes in North ...

Darragh, Miss.

2008-10-25

399

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

USGS Publications Warehouse

Lack of recruitment and canopy replacement of aspen (Populus tremuloides) stands that grow on the edges of grasslands on the low-elevation elk (Cervus elaphus) winter range of Rocky Mountain National Park (RMNP) in Colorado have been a cause of concern for more than 70 years. We used a combination of traditional dendrochronology and genetic techniques as well as measuring the characteristics of regenerating and nonregenerating stands on the elk winter range to determine when and under what conditions and estimated elk densities these stands established and through what mechanisms they may regenerate. The period from 1975 to 1995 at low elevation on the east side had 80-95 percent fewer aspen stems than would be expected based on the trend from 1855 through 1965. The age structure of aspen in the park indicates that the interacting effects of fires, elk population changes, and livestock grazing had more-or-less consistent effects on aspen from 1855 to 1965. The lack of a significant change in aspen numbers in recent decades in the higher elevation and west side parts of the park supports the idea that the extensive effects of elk browsing have been more important in reducing aspen numbers than other factors. The genetic variation of aspen populations in RMNP is high at the molecular level. We expected to find that most patches of aspen in the park were composed of a single clone of genetically identical trees, but in fact just 7 percent of measured aspen patches consisted of a single clone. A large frequency of polyploid (triploid and tetraploid) genotypes were found on the low elevation, east-side elk winter range. Nonregenerating aspen stands on the winter range had greater annual offtake, shorter saplings, and lower density of mid-height (1.5-2.5 m) saplings than regenerating stands. Overwinter elk browsing, however, did not appear to inhibit the leader length of aspen saplings. The winter range aspen stands of RMNP appear to be highly resilient in the face of very intense herbivory by elk and harsh environmental conditions. Conservation efforts through fencing protection and decreased elk browsing pressure are already being planned as part of the park's new elk management plan. If these efforts are undertaken, conditions that encourage stem recruitment to the tree canopy will likely result and the continued survival of these aspen stands will be enhanced.

Zeigenfuss, Linda C.; Binkley, Dan; Tuskan, Gerald A.; Romme, William H.; Yin, Tongming; DiFazio, Stephen; Singer, Francis J.

2008-01-01

400

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

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.

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

1985-06-01

401

Respiratory and mental health effects of wildfires: an ecological study in Galician municipalities (north-west Spain)  

PubMed Central

Background During the summer of 2006, a wave of wildfires struck Galicia (north-west Spain), giving rise to a disaster situation in which a great deal of the territory was destroyed. Unlike other occasions, the wildfires in this case also threatened farms, houses and even human lives, with the result that the perception of disaster and helplessness was the most acute experienced in recent years. This study sought to analyse the respiratory and mental health effects of the August-2006 fires, using consumption of anxiolytics-hypnotics and drugs for obstructive airway diseases as indicators. Methods We conducted an analytical, ecological geographical- and temporal-cluster study, using municipality-month as the study unit. The independent variable was exposure to wildfires in August 2006, with municipalities thus being classified into the following three categories: no exposure; medium exposure; and high exposure. Dependent variables were: (1) anxiolytics-hypnotics; and (2) drugs for obstructive airway diseases consumption. These variables were calculated for the two 12-month periods before and after August 2006. Additive models for time series were used for statistical analysis purposes. Results The results revealed a higher consumption of drugs for obstructive airway diseases among pensioners during the months following the wildfires, in municipalities affected versus those unaffected by fire. In terms of consumption of anxiolytics-hypnotics, the results showed a significant increase among men among men overall -pensioners and non-pensioners- in fire-affected municipalities. Conclusions Our study indicates that wildfires have a significant effect on population health. The coherence of these results suggests that drug utilisation research is a useful tool for studying morbidity associated with environmental incidents.

2011-01-01

402

A review on numerous modeling approaches for effective, economical and ecological treatment wetlands.  

PubMed

Constructed wetlands (CWs) for wastewater treatment have evolved substantially over the last decades and have been recognized as an effective means of "green technology" for wastewater treatment. This paper reviews the numerous modeling approaches ranging from simple first-order models to more complex dynamic models of treatment behaviour in CWs. The main objective of the modeling work is to better understand the process in CWs and optimize design criteria. A brief study in this review discusses the efforts taken to describe the process-based model for the efficient removal of pollutants in CWs. Obtaining better insights is essential to understand the hydraulic and biochemical processes in CWs. Currently, employed modeling approaches can be seen in two categories, i.e. "black-box models" and "process-based models". It is evident that future development in wetland technology will depend on improved scientific knowledge of internal treatment mechanisms. PMID:21134712

Kumar, J L G; Zhao, Y Q

2011-03-01

403

Contrasting effects of rising CO2 on primary production and ecological stoichiometry at different nutrient levels.  

PubMed

Although rising CO2 concentrations are thought to promote the growth and alter the carbon : nutrient stoichiometry of primary producers, several studies have reported conflicting results. To reconcile these contrasting results, we tested the following hypotheses: rising CO2 levels (1) will increase phytoplankton biomass more at high nutrient loads than at low nutrient loads, but (2) will increase their carbon : nutrient stoichiometry more at low than at high nutrient loads. We formulated a mathematical model to predict dynamic changes in phytoplankton population density, elemental stoichiometry and inorganic carbon chemistry in response to rising CO2 . The model was tested in chemostat experiments with the freshwater cyanobacterium Microcystis aeruginosa. The model predictions and experimental results confirmed the hypotheses. Our findings provide a novel theoretical framework to understand and predict effects of rising CO2 concentrations on primary producers and their nutritional quality as food for herbivores under different nutrient conditions. PMID:24813339

Verspagen, Jolanda M H; Van de Waal, Dedmer B; Finke, Jan F; Visser, Petra M; Huisman, Jef

2014-08-01

404

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

USGS Publications Warehouse

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.

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

1996-01-01

405

Temporal and maternal effects on reproductive ecology of the giant gartersnake (Thamnophis gigas)  

USGS Publications Warehouse

We used mixed-effects models to examine relationships of reproductive characteristics of the giant gartersnake (Thamnophis gigas) to improve population modeling and conservation planning for this species. Neonates from larger litters had lower mass, and mass of neonates also was affected by random variation among mothers. Length of mother did not affect relative mass of litters; however, our data suggest that longer mothers expended less reproductive effort per offspring than shorter mothers. We detected random variation in length of neonates among mothers, but these lengths were not related to length of mother or size of litter. Mean size of litter varied among years, but little evidence existed for a relationship between size of litter or mass of litter and length of mother. Sex ratios of neonates did not differ from 1:1.

Halstead, B. J.; Wylie, G. D.; Casazza, M. L.; Coates, P. S.

2011-01-01

406

The ecology of infectious disease: Effects of host diversity and community composition on Lyme disease risk  

PubMed Central

The extent to which the biodiversity and community composition of ecosystems affect their functions is an issue that grows ever more compelling as human impacts on ecosystems increase. We present evidence that supports a novel function of vertebrate biodiversity, the buffering of human risk of exposure to Lyme-disease-bearing ticks. We tested the Dilution Effect model, which predicts that high species diversity in the community of tick hosts reduces vector infection prevalence by diluting the effects of the most competent disease reservoir, the ubiquitous white-footed mouse (Peromyscus leucopus). As habitats are degraded by fragmentation or other anthropogenic forces, some members of the host community disappear. Thus, species-poor communities tend to have mice, but few other hosts, whereas species-rich communities have mice, plus many other potential hosts. We demonstrate that the most common nonmouse hosts are relatively poor reservoirs for the Lyme spirochete and should reduce the prevalence of the disease by feeding, but rarely infecting, ticks. By accounting for nearly every host species' contribution to the number of larval ticks fed and infected, we show that as new host species are added to a depauperate community, the nymphal infection prevalence, a key risk factor, declines. We identify important “dilution hosts” (e.g., squirrels), characterized by high tick burdens, low reservoir competence, and high population density, as well as “rescue hosts” (e.g., shrews), which are capable of maintaining high disease risk when mouse density is low. Our study suggests that the preservation of vertebrate biodiversity and community composition can reduce the incidence of Lyme disease.

LoGiudice, Kathleen; Ostfeld, Richard S.; Schmidt, Kenneth A.; Keesing, Felicia

2003-01-01