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1

Betel nut chewing and its deleterious effects on oral cavity.  

PubMed

The habit of chewing betel nut has a long history of use. Betel nut and products derived from it are widely used as a masticatory product among various communities and in several countries across the world. Over a long period, several additives have been added to a simple betel nut preparation; thus, creating the betel quid (BQ) and encompassing chewing tobacco in the preparation. Betel nut has deleterious effects on oral soft tissues. Its effects on dental caries and periodontal diseases, two major oral diseases are less well-documented. Betel-induced lichenoid lesions mainly on buccal mucosa have been reported at quid retained sites. In chronic chewers, a condition called betel chewers mucosa is often found where the quid is placed. Betel nut chewing is implicated in oral submucous fibrosis (OSF) and its use along with tobacco can cause leukoplakia, both of which are potentially malignant in the oral cavity. Oral cancer often arises from such precancerous changes. Thus, public health measures to quit betel use are recommended to control disabling conditions such as OSF and oral cancer. PMID:25313728

Anand, Richa; Dhingra, Chandan; Prasad, Sumanth; Menon, Ipseeta

2014-01-01

2

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

E-print Network

of the endangered fire salamander Salamandra infraimmaculata in northern Israel. A comparison of Salamandra larvaeDeleterious effects by mosquitofish (Gambusia affinis) on the endangered fire salamander

Blaustein, Leon

3

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

PubMed

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

John, Sona; Jain, Kavita

2015-01-21

4

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

5

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. PMID:24189375

Klari?, Maja Šegvi?; Raši?, Dubravka; Peraica, Maja

2013-01-01

6

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

7

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

8

Highly deleterious role of small amounts of carbon on the giant magnetoresistance effect  

E-print Network

Highly deleterious role of small amounts of carbon on the giant magnetoresistance effect David X (2011) Sign change of tunnel magnetoresistance ratio with temperature in epitaxial Fe/MgO/Co2MnSn magnetic tunnel junctions J. Appl. Phys. 110, 073905 (2011) Enhancement of magnetoresistance by ultra

Chopra, Harsh Deep

9

DELETERIOUS RHIZOBACTERIA  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

10

Certitudes and controversies regarding the deleterious effects of low doses ionizing radiation.  

PubMed

The problem of the deleterious effects of ionizing radiation must be a constant preoccupation of the medical staff. We must never forget that radiations can cure (by increasing the diagnostic accuracy and by the benefic use of radiotherapy), but can also generate cancer and genomic instability. All the governments have the desire to use the "cheap" (it's cheap when you do not take into consideration all the spenditures regarding the monitorisation of radiation workers and the cost of decontamination) nuclear energy. We must underline, also, the fact that a too frequent exposure to ionizing radiation (especially by CT examinations) is generating undesired consequences, and that the direct irradiation and the bystander effect can create a genomic instability that is "transferred" to the following generation. As, nowadays, it is almost impossible to live in an environment devoid of risks, we must try to reduce them significantly. PMID:23610975

B?lan, H; B?l?ceanu, Alice Lavinia

2012-01-01

11

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

PubMed

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

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

2015-02-01

12

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

PubMed Central

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

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

2014-01-01

13

Prediction of deleterious functional effects of amino acid mutations using a library of structure-based function descriptors.  

PubMed

An automated, active site-focused, computational method is described for use in predicting the effects of engineered amino acid mutations on enzyme catalytic activity. The method uses structure-based function descriptors (Fuzzy Functional Forms trade mark or FFFs trade mark ) to automatically identify enzyme functional sites in proteins. Three-dimensional sequence profiles are created from the surrounding active site structure. The computationally derived active site profile is used to analyze the effect of each amino acid change by defining three key features: proximity of the change to the active site, degree of amino acid conservation at the position in related proteins, and compatibility of the change with residues observed at that position in similar proteins. The features were analyzed using a data set of individual amino acid mutations occurring at 128 residue positions in 14 different enzymes. The results show that changes at key active site residues and at highly conserved positions are likely to have deleterious effects on the catalytic activity, and that non-conservative mutations at highly conserved residues are even more likely to be deleterious. Interestingly, the study revealed that amino acid substitutions at residues in close contact with the key active site residues are not more likely to have deleterious effects than mutations more distant from the active site. Utilization of the FFF-derived structural information yields a prediction method that is accurate in 79-83% of the test cases. The success of this method across all six EC classes suggests that it can be used generally to predict the effects of mutations and nsSNPs for enzymes. Future applications of the approach include automated, large-scale identification of deleterious nsSNPs in clinical populations and in large sets of disease-associated nsSNPs, and identification of deleterious nsSNPs in drug targets and drug metabolizing enzymes. PMID:14635123

Herrgard, Sanna; Cammer, Stephen A; Hoffman, Brian T; Knutson, Stacy; Gallina, Marijo; Speir, Jeffrey A; Fetrow, Jacquelyn S; Baxter, Susan M

2003-12-01

14

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

15

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

PubMed Central

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

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

2005-01-01

16

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. PMID:24967385

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

2014-01-01

17

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

18

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

PubMed

Liver X receptors LXR? (NR1H3) and LXR? (NR1H2) are transcription factors belonging to the nuclear receptor superfamily, activated by specific oxysterols, oxidized derivatives of cholesterol. These receptors are involved in the regulation of testis physiology. Lxr-deficient mice pointed to the physiological roles of these nuclear receptors in steroid synthesis, lipid homeostasis and germ cell apoptosis and proliferation. Diethylstilbestrol (DES) is a synthetic estrogen considered as an endocrine disruptor that affects the functions of the testis. Various lines of evidences have made a clear link between estrogens, their nuclear receptors ER? (NR3A1) and ER? (NR3A2), and Lxr?/?. As LXR activity could also be regulated by the nuclear receptor small heterodimer partner (SHP, NR0A2) and DES could act through SHP, we wondered whether LXR could be targeted by estrogen-like endocrine disruptors such as DES. For that purpose, wild-type and Lxr-deficient mice were daily treated with 0.75 ?g DES from days 1 to 5 after birth. The effects of DES were investigated at 10 or 45 days of age. We demonstrated that DES induced a decrease of the body mass at 10 days only in the Lxr-deficient mice suggesting a protective effect of Lxr. We defined three categories of DES-target genes in testis: those whose accumulation is independent of Lxr; those whose accumulation is enhanced by the lack of both Lxr?/?; those whose accumulation is repressed by the absence of Lxr?/?. Lipid accumulation is also modified by neonatal DES injection. Lxr-deficient mice present different lipid profiles, demonstrating that DES could have its effects in part due to Lxr?/?. Altogether, our study shows that both nuclear receptors Lxr? and Lxr? are not only basally important for testicular physiology but could also have a preventive effect against estrogen-like endocrine disruptors. PMID:24333430

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

2014-04-11

19

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

20

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

PubMed

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

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

2015-02-01

21

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

22

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

PubMed Central

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

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

2013-01-01

23

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. PMID:24348548

Buthet, Lara Romina; Maciel, María Eugenia; Quintans, Leandro Néstor; Rodríguez de Castro, Carmen; Costantini, Martín Hernán; Castro, José Alberto

2013-01-01

24

RAGE: The Beneficial and Deleterious Effects by Diverse Mechanisms of Actions  

PubMed Central

Receptor for advanced glycation endproducts (RAGE) is a transmembrane protein that belongs to the immunoglobu-lin superfamily. RAGE is expressed ubiquitously-high in lung and moderate to low in a wide range of cells-in a tightly regulated manner at various stages of development. RAGE is a pattern recognition receptor that binds to multi-ple ligands, including amphoterin, members of the S100/ calgranulin family, the integrin Mac-1, and amyloid ?-pep-tide (A?). RAGE-ligand engagement effects the activation of diverse cascades that initiate and stimulate chronic stress pathways and repair, depending on the ligand, envi-ronment, and developmental stage. Further, RAGE-ligand interaction and the consequent upregulation of RAGE through a positive feedback loop are often associated with various diseases, including vascular disease, diabetes, cancer, and neurodegenerative disease. It is unknown how RAGE mediates these events, but such phenomena ap-pear to be linked to the inflammatory response. In this review, we summarize the findings on RAGE from pub-lished reports and ongoing studies. Also, the implication of RAGE in Alzheimer disease, the most common neuro-degenerative disease in the elderly population, will be dis-cussed, with a focus on A?-RAGE interactions with regard to signaling pathways and their impact on cellular activity. PMID:21347704

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

2011-01-01

25

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

PubMed

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

Buthet, Lara Romina; Maciel, María Eugenia; Quintans, Leandro Néstor; Rodríguez de Castro, Carmen; Costantini, Martín Hernán; Fanelli, Silvia Laura; Castro, José Alberto; Castro, Gerardo Daniel

2013-01-01

26

Using ergosterol to mitigate the deleterious effects of ethanol on bilayer structure  

PubMed Central

In wine fermentations, yeast is exposed to concentrated ethanol solutions. Ergosterol, a sterol that is found in lower eukaryotic membranes, helps preserve the structural integrity of yeast membranes in stressful environmental conditions. A premature arrest in ethanol production due to unknown metabolic changes in yeasts results in undesirably large concentrations of residual sugar and may be caused by the formation of an ethanol-induced interdigitated phase. We use atomistic Molecular Dynamics simulations to examine the induction of the interdigitated phase in model yeast membranes that contain either 0, 10, 20, 25 mol% ergosterol in ethanol concentrations of 0, 10, 15 vol%. The 25 mol% ergosterol system shows a similar level of interdigitation for the 0 and 10 vol% ethanol solutions, indicating that ergosterol molecules in this system are able to effectively counteract the disruptive behavior of ethanol molecules. However, at a 15 vol% ethanol solution, the amount of interdigitation triples and this ethanol concentration is similar to the concentrations found in stuck fermentations. The other three ergosterol concentrations studied (0, 10, 20 mol%) show larger quantities of interdigitation in the 10 vol% ethanol solution than the 0 vol% solution. Thus, the 25 mol% ergosterol bilayer, which is representative of the ergosterol concentrations seen in yeast membranes, is unique in the systems examined in its ability to delay the onset of ethanol-induced interdigitation. The concentration of ergosterol affects the permeability of a fiuid-phase bilayer, where the 10 mol% ergosterol bilayer is more permeable to ethanol than either a bilayer containing no ergosterol molecules or a bilayer containing 20/25 mol% ergosterol. This lipid permeability appears to be correlated with the existence of a lipid region whose lipids neither have direct contact with ergosterol molecules nor exhibit bulk lipid/lipid interactions. PMID:19191714

Dickey, Allison N.; Yim, Wen-Sau; Faller, Roland

2009-01-01

27

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

PubMed

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

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

2010-02-01

28

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

PubMed Central

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

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

2014-01-01

29

Deleterious effects of white cells in the course of skin damage in CVI.  

PubMed

Venous ulceration remains a common problem and a significant challenge to the physicians treating it. Many theories have been advanced in the past to explain its causes but there is little evidence to support tissue hypoxia as the main factor, as was once thought. In recent years attention has focussed on the inflammatory events which attend venous disease and the development of venous ulceration. It has been proposed that these form a major contribution to the development of venous leg ulcers. In the arterial system an analogous series of events appears to cause damage following severe ischemia. Massive neutrophil activation in the microcirculation following reperfusion of a tissue results in severe, ischemic damage to that tissue. A similar series of events is proposed to explain venous disease. During venous hypertension leukocytes are sequestrated in the microcirculation of the lower limb. It has been shown that these undergo activation whilst they are in the leg. The exact location of leukocyte sequestration is unclear but it is suggested that this may occur in the skin. The damage caused to the lower limb skin components can be identified by measuring plasma levels of endothelial adhesion molecules, which are shed into the circulation following a period of venous hypertension. In the long term this leads to a chronic inflammatory state in the skin in some patients where venous hypertension is sustained or there is susceptibility to venous hypertension. The resulting inflammatory process is referred to as "lipodermatosclerosis" and has a number of well known clinical features. There is proliferation of the dermal capillaries eventually leading to a "glomerulus" like appearance. In the skin and subcutaneous tissues there is fibrosis. The microcirculation in the papillary dermis is surrounded by an inflammatory cellular infiltrate. The importance of understanding the mechanisms of the development of venous ulceration is in creating new treatments for this problem. Compression treatment has been effective in healing leg ulcers for thousands of years. Surgical treatment offers a possible cure in patients where superficial venous reflux is the main problem. Deep vein reconstruction is only suitable for a few patients. Many venous ulcers can be healed by compression, only to recur within a few months. Pharmacological treatments may offer the possibility of more rapid ulcer healing and the maintenance of an ulcer-free state if the correct pathophysiological mechanisms can be identified and addressed. PMID:12515977

Coleridge Smith, P D

2002-06-01

30

The deleterious effects of long-term cyclosporine A, cyclosporine G, and FK506 on bone mineral metabolism in vivo.  

PubMed

Administration of cyclosporine A to male and female rats accelerates bone remodeling and causes bone loss, among other side-effects. The newer immunosuppressant drugs, FK506 and CsG, have been synthesized to counteract the toxic effects of CsA, yet maintain clinical efficacy. We investigated the in vivo effects of long-term administration of these drugs on bone mineral metabolism in the rat. Five groups of Sprague-Dawley rats, 15 per group, were allocated to receive by daily gavage for a period of 28 days: (1) Cs-vehicle; (2) CsA 15 mg/kg b.w.; (3) CsG 15 mg/kg b.w.; (4) FK506 vehicle; (5) FK506 5 mg/kg b.w. Blood was sampled on days 0, 14, and 28 for measurement of ionized calcium (Ca2+), parathyroid hormone (PTH), 1,25-(OH)2-vitamin D, and bone gla protein (BGP). Tibiae were removed on day 28 after double calcein labeling for histomorphometric analysis. Immunosuppressant groups were compared with the respective vehicle groups. Neither CsA or CsG affected the levels of Ca2+ or PTH, whereas by day 28 FK506 caused a decrease in Ca2+ and a corresponding rise in PTH (P < 0.05). The 1,25-(OH)2-vitamin D and BGP levels in both the CsA and CsG groups were increased on days 14 and 28 (P < 0.05), while FK506 had no effect on these serum levels. Tibial bone histomorphometry revealed that all 3 immunosuppressants increased measures of bone formation and bone resorption, accompanied by a significant reduction in percent trabecular area, most marked with FK506. This report demonstrates that all three immunosuppressants have adverse effects on bone--most deleterious with FK506. PMID:7513912

Cvetkovic, M; Mann, G N; Romero, D F; Liang, X G; Ma, Y; Jee, W S; Epstein, S

1994-04-27

31

CONTAMINATED SEDIMENTS - ECOLOGICAL EFFECTS RESEARCH  

EPA Science Inventory

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

32

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

PubMed Central

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

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

2015-01-01

33

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

PubMed Central

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

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

2014-01-01

34

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

35

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

PubMed Central

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

2013-01-01

36

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

37

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

PubMed Central

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

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

2013-01-01

38

Testing the ability of non-methylamine osmolytes present in kidney cells to counteract the deleterious effects of urea on structure, stability and function of proteins.  

PubMed

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

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

2013-01-01

39

Identification and analysis of deleterious human SNPs.  

PubMed

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

Yue, Peng; Moult, John

2006-03-10

40

Deleterious effects of a nonPST bioactive compound(s) from Alexandrium tamarense on bivalve hemocytes  

Microsoft Academic Search

The known negative effects of shellfish toxin-producing dinoflagellates on feeding, burrowing and survival of some bivalve\\u000a mollusks has prompted questions concerning whether they might also impair the internal defense system of affected bivalves\\u000a and make them more susceptible to disease agents. The primary components of the cellular defense system are hemocytes. Many\\u000a toxic dinoflagellates are too large to be ingested

Susan E. Ford; V. Monica Bricelj; Christophe Lambert; Christine Paillard

2008-01-01

41

N-Acetylcysteine Prevents Deleterious Effects of Ischemia\\/Reperfusion Injury on Healing of Colonic Anastomosis in Rats  

Microsoft Academic Search

This study was designed to determine the effects of intraperitoneally or orally administered N-acetylcysteine (NAC) on wound healing following resection and anastomosis of a colon segment with ischemia\\/reperfusion injury. Forty female Spraque-Dawley rats were randomly allocated to one of four groups containing 10 rats each: (1) normal resection plus anastomosis; (2) ischemia\\/reperfusion plus resection plus anastomosis; (3) ischemia\\/reperfusion plus resection

B. Kabali; S. Girgin; E. Gedik; H. Ozturk; E. Kale; H. Buyukbayram

2009-01-01

42

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

43

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

PubMed Central

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

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

2014-01-01

44

The antioxidant epigallocatechin gallate (EGCG) moderates the deleterious effects of maternal hyperthermia on follicle-enclosed oocytes in mice.  

PubMed

Hyperthermia-induced oxidative stress is one of the mechanisms suggested to underlie loss of developmental competence in mouse embryos. In this study, we examined whether pretreatment with the antioxidant epigallocatechin gallate (EGCG) can alleviate the negative effects of hyperthermia on developmental competence of the ovarian pool of oocytes and improve embryonic development. Female mice (CB6F1) were synchronized (eCG+hCG) and injected with 0.4 ml EGCG (100 mg/kg body weight) or with saline. Both EGCG- and saline-treated mice were exposed to heat stress (HS; 40 degrees C, 65% RH) or kept under normothermal conditions (Control; 22 degrees C, 45% RH). In vivo-derived zygotes were recovered 20 h after hCG administration and cultured in vitro. Maternal hyperthermia attenuated embryonic cleavage rate in association with further disruption in embryonic early cleavage and subsequently, with embryonic development. While pretreatment with EGCG did not affect the proportion of zygotes that cleaved to the two-cell stage, it appeared to moderate the effect of hyperthermia on both cleavage timing and developmental rate, as reflected by an increased rate of early cleaved embryos and blastocyst formation. Blastocyst developmental competence was also improved, as indicated by the increased total cell number and percentage of embryos that underwent hatching, in association with reduced apoptotic status, as reflected by the percentage of TUNEL-positive cells and intensity of caspase activity for the HS-EGCG embryos vs. HS-saline ones. In summary, while hyperthermia disrupts the competence of the follicle-enclosed oocyte, in vivo administration of the antioxidant EGCG improves developmental competence and the quality of the embryos that develop from these oocytes. PMID:18585774

Roth, Z; Aroyo, A; Yavin, S; Arav, A

2008-10-01

45

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

46

The Balance of Beneficial and Deleterious Health Effects of Quinones: A Case Study of the Chemical Properties of Genistein and Estrone Quinones  

PubMed Central

Substances containing a phenolic moiety are often metabolized to quinones whose high reactivity makes them difficult to study. Some of these precursors have clear health benefits, and some quinones themselves are used in cancer therapy, whereas others are deleterious. For example, dietary intake of phytoestrogen, genistein (Gen), seems to play a preventive role in breast cancer (BC) whereas prolonged exposure to chemically similar mammalian estrogens is clearly associated with elevated incidence of BC. Although both can be metabolized to reactive quinones, the catechol estrogen quinones (CEQs) modify DNA by redox cycling and/or depurination via a Michael addition. Here, we report an investigation of the chemical reactivity of Gen and estrone quinones to determine the chemical differences in of these two biologically important molecules. The catechol genistein quinone (CGenQ), has a half life of 4 ± 1 s under physiological condition, as determined by glutathione trapping. It disappears by reacting with H2O to give a dihydrate, CGenQ·(H2O)2, whose structure was proved by NMR. Under reductive conditions, CGenQ·(H2O)2 is readily reduced to reform the catechol genistein (CGen). This reversible oxidation of CGen to CGenQ and the prompt moderation of its reactivity by hydration to CGenQ·(H2O)2 effectively moderates any redox cycling or depurination reaction of CGenQ with DNA. Catechol estrogen quinones, on the other hand, are sufficiently long-lived that they can damage DNA via a Michael addition or by redox cycling. Although the reactivity of CEQ in a nonaqueous solvent is similar to that of CGenQ, its reactivity in aqueous media with the free Ade base is more than 600 times that of CGenQ. These results suggest that rapid hydration of a quinone can moderate its reactivity toward biomolecules, allowing them to express, for example, estrogen-like properties without exhibiting the deleterious properties of redox cycling or directly damaging DNA via depurination reactions. PMID:19115854

Zhang, Qiang; Tu, Tingting; d’Avignon, D. André; Gross, Michael L.

2009-01-01

47

The Pattern and Distribution of Deleterious Mutations in Maize  

PubMed Central

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

Mezmouk, Sofiane; Ross-Ibarra, Jeffrey

2013-01-01

48

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

49

GVHD prophylaxis with sirolimus-tacrolimus may overcome the deleterious effect on survival of HLA mismatch after reduced-intensity conditioning allo-SCT.  

PubMed

Large studies, mostly based on series of patients receiving CSA/tacrolimus (TKR) plus MTX as immunoprophylaxis, have demonstrated a deleterious effect on survival of the presence of a single mismatch out of eight loci after allogeneic hematopoietic SCT (alloHSCT). We retrospectively analyzed a series of 159 adult patients who received sirolimus(SRL)/TKR prophylaxis after alloHSCT. We compared overall outcomes according to HLA compatibility in A, B, C and DRB1 loci at the allele level: 7/8 (n=20) vs 8/8 (n=139). Donor type was unrelated in 95% vs 70% among 7/8 vs 8/8 pairs, respectively (P=0.01). No significant differences were observed in 3-year OS (68 vs 62%), 3-year EFS (53 vs 49%) and 1-year non-relapse mortality (9 vs 13%). Cumulative incidence of grades II-IV acute GVHD (aGVHD) was significantly higher in 7/8 alloHSCT (68% vs 42%, P<0.001) but no significant differences were found for III-IV aGVHD (4.5% vs 11%), overall (35% vs 53%) and extensive (20% vs 35%) chronic GHVD in 7/8 vs 8/8 subgroups, respectively. In summary, the present study indicates favorable outcomes after alloHSCT using the combination of SRL/TKR combination as GVHD prophylaxis with OS in the range of 55-70%, and non-significant differences in overall outcomes, irrespective of the presence of any mismatches at obligatory loci. PMID:25310306

Parody, R; Lopez-Corral, L; Godino, O L; Cadenas, I G; Martinez, A P; Vazquez, L; Martino, R; Martinez, C; Solano, C; Barba, P; Valcarcel, D; Caballero-Velazquez, T; Marquez-Malaver, F J; Sierra, J; Caballero, D; Perez-Simón, J A

2015-01-01

50

Overproduction of the rbo gene product from Desulfovibrio species suppresses all deleterious effects of lack of superoxide dismutase in Escherichia coli.  

PubMed Central

In an attempt to isolate the superoxide dismutase (SOD) gene from the anaerobic sulfate-reducing bacterium Desulfoarculus baarsii, a DNA fragment was isolated which functionally complemented an Escherichia coli mutant (sodA sodB) deficient in cytoplasmic SODs. This region carries two open reading frames with sequences which are very similar to that of the rbo-rub operon from Desulfovibrio vulgaris. Independent expression of the rbo and rub genes from ptac showed that expression of rbo was responsible for the observed phenotype. rbo overexpression suppressed all deleterious effects of SOD deficiency in E. coli, including inactivation by superoxide of enzymes containing 4Fe-4S clusters and DNA damage produced via the superoxide-enhanced Fenton reaction. Thus, rbo restored to the sodA sodB mutant the ability to grow on minimal medium without the addition of branched amino acids, and growth on gluconate and succinate carbon sources was no longer impaired. The spontaneous mutation rate, which is elevated in SOD-deficient mutants, returned to the wild-type level in the presence of Rbo, which also restored aerobic viability of sodA sodB recA mutants. Rbo from Desulfovibrio vulgaris, but not Desulfovibrio gigas desulforedoxin, which corresponds to the NH2-terminal domain of Rbo, complemented sod mutants. The physiological role of Rbo in sulfate-reducing bacteria is unknown. In E. coli, Rbo may permit the bacterium to avoid superoxide stress by maintaining functional (reduced) superoxide sensitive 4Fe-4S clusters. It would thereby restore enzyme activities and prevent the release of iron that occurs after cluster degradation and presumably leads to DNA damage. PMID:8955290

Pianzzola, M J; Soubes, M; Touati, D

1996-01-01

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

An assessment of the ecological effects of acidic deposition  

Microsoft Academic Search

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

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

1989-01-01

53

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...

54

Deleterious GRM1 mutations in schizophrenia.  

PubMed

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

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

2012-01-01

55

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

PubMed

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

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

2008-06-01

56

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...

57

Ecology of estuaries: Anthropogenic effects  

Microsoft Academic Search

Estuaries and near-shore oceanic water are subjected to a multitude of human wastes. The principal objective of this book is to examine anthropogenic effects on estuaries, and it focuses primarily on contaminants in coastal systems. Covered within various chapters are the following topics: waste disposal strategies; definition and classification of pollutants (including organic loading, oil pollution, polynuclear aromatic hydrocarbons; chlorinated

Kennish; Michael J. Kennish

1992-01-01

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. PMID:24820200

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

2014-01-01

59

EN-006 Ecology March 2001 Effects of Alternative Silvicultural Treatments  

E-print Network

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

60

The chemical ecology of Harmonia axyridis  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

61

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

62

Deleterious amino acid polymorphisms in Arabidopsis thaliana and rice.  

PubMed

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

Günther, Torsten; Schmid, Karl J

2010-06-01

63

High Frequency of Cryptic Deleterious Mutations in  

E-print Network

percent of the deleterious mutations fixed in each line were detectable. The remaining 96 percent, though [using a log-odds (Dayhoff) matrix (16)] arising from G/C 3 A/T transitions to other types of point

Keightley, Peter

64

Palytoxin and Analogs: Biological and Ecological Effects  

PubMed Central

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

Ramos, Vítor; Vasconcelos, Vítor

2010-01-01

65

Palytoxin and analogs: biological and ecological effects.  

PubMed

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

Ramos, Vítor; Vasconcelos, Vítor

2010-01-01

66

SPS microwave health and ecological effects: Program area overview  

NASA Technical Reports Server (NTRS)

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

Cahill, D. F.

1980-01-01

67

Deleterious mutation accumulation in organelle genomes  

Microsoft Academic Search

It is well established on theoretical grounds that the accumulation of mildly deleterious mutations in nonrecombining genomes is a major extinction risk in obligately asexual populations. Sexual populations can also incur mutational deterioration in genomic regions that experience little or no recombination, i.e., autosomal regions near centromeres, Y chromosomes, and organelle genomes. Our results suggest, for a wide array of

Michael Lynch; Jeffrey L. Blanchard

1998-01-01

68

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

PubMed

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

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

2015-02-01

69

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

PubMed

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

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

2013-01-15

70

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

PubMed Central

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

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

2014-01-01

71

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

PubMed

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

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

2008-07-01

72

Potential Ecological Effects of Marcellus Shale Activities  

E-print Network

(aquifer) water through disruption or contamination · Gas migration leading to methane contamination · Fate · Offgasing from · condensate and · storage tanks · Vs. oil and coal #12;Ecological Impacts ­ Chemical Use · Fracking fluids (How many carcinogens?) · Produced water contaminated with organics, salts, heavy metals

Jiang, Huiqiang

73

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

74

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

PubMed Central

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

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

2014-01-01

75

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

PubMed

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

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

2014-01-01

76

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

77

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

PubMed

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

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

2009-12-01

78

Deleterious mutation accumulation in organelle genomes  

Microsoft Academic Search

It is well established on theoretical grounds that the accumulation of mildly deleterious mutations in nonrecombining genomes\\u000a is a major extinction risk in obligately asexual populations. Sexual populations can also incur mutational deterioration in\\u000a genomic regions that experience little or no recombination, i.e., autosomal regions near centromeres, Y chromosomes, and organelle\\u000a genomes. Our results suggest, for a wide array of

Michael Lynch; Jeffrey L. Blanchard

1998-01-01

79

Integrated Modeling for the Assessment of Ecological Impacts of Sea Level Rise  

Microsoft Academic Search

Sea level rise (SLR) has the potential to affect a variety of coastal habitats with a myriad of deleterious ecological effects and to overwhelm human settlements along the coast. SLR should be given serious consideration when more than half of the U.S. population lives within 50 miles of the coast. SLR effects will be felt along coastal beaches and in

S. C. Hagen; G. Lewis; R. Bartel; B. Batten; W. Huang; J. Morris; D. N. Slinn; J. Sparks; L. Walters; D. Wang; J. Weishampel; G. Yeh

2010-01-01

80

21 CFR 109.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2012 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2012-04-01

81

21 CFR 509.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2013 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2013-04-01

82

21 CFR 509.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2010 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2010-04-01

83

21 CFR 509.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2014 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2014-04-01

84

21 CFR 509.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2011 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2011-04-01

85

21 CFR 109.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2010 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2010-04-01

86

21 CFR 109.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2011 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2011-04-01

87

21 CFR 109.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2014 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2014-04-01

88

21 CFR 109.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2013 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2013-04-01

89

21 CFR 509.6 - Added poisonous or deleterious substances.  

Code of Federal Regulations, 2012 CFR

...tolerance for an added poisonous or deleterious substance in any food may be established...limit for an added poisonous or deleterious substance in any food may be established...level for an added poisonous or deleterious substance in any food may be...

2012-04-01

90

Ecology.  

ERIC Educational Resources Information Center

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

National Audubon Society, New York, NY.

91

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

E-print Network

three decades, China's economy has grown the fastest among all major nations. By contrast, ChinaEcological and socioeconomic effects of China's policies for ecosystem services Jianguo Liu Academy of Sciences, Beijing 100085, China; and §Department of Biology and Natural Capital Project, Woods

92

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

93

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

94

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

PubMed

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

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

2014-10-01

95

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

EPA Science Inventory

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

96

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...

97

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...

98

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

PubMed

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

Chassy, Philippe; Gobet, Fernand

2013-01-01

99

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

PubMed Central

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

Chassy, Philippe; Gobet, Fernand

2013-01-01

100

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. PMID:18621700

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

2008-01-01

101

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

NASA Astrophysics Data System (ADS)

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

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

102

Ecological effects of mercury in aquatic ecosystems  

SciTech Connect

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

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

1994-12-31

103

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

NASA Astrophysics Data System (ADS)

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

Kibota, Travis T.; Lynch, Michael

1996-06-01

104

Identification of deleterious mutations within three human genomes  

PubMed Central

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

Chun, Sung; Fay, Justin C.

2009-01-01

105

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. PMID:24874801

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

2014-01-01

106

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

Microsoft Academic Search

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

Muhammad Sarwar; Robert J. Kremer

1995-01-01

107

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

108

Ecological effects of contaminants and remedial actions in Bear Creek  

SciTech Connect

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

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

1992-01-01

109

Genetic variation in response to an indirect ecological effect  

PubMed Central

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

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

2005-01-01

110

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

NASA Astrophysics Data System (ADS)

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

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

2005-05-01

111

Land Use Effects on Ecological Linkages between Small Streams and their  

E-print Network

Land Use Effects on Ecological Linkages between Small Streams and their Surrounding Terrestrial) #12;Land Use Effects on Ecological Linkages between Small Streams and their Surrounding Terrestrial insects. Agricultural land use often results in the degradation of in-stream and riparian habitats which

112

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

E-print Network

A synthesis of the "Ecological Effects of Reservoir Operations at Blue Mesa Reservoir" Project RESERVOIR AND FOOD WEB DYNAMICS AT BLUE MESA RESERVOIR, COLORADO, 1993-2002 U.S. Department of the Interior June 2005 #12;2 RECLAMATION A synthesis of the "Ecological Effects of Reservoir Operations at Blue Mesa

113

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 ...

114

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

E-print Network

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

Cochran-Stafira, D. Liane

115

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 ...

116

Acidic precipitation, Vol. 2: Biological and ecological effects  

SciTech Connect

Acidic precipitation has its origin in emissions to the atmosphere of numerous compounds from both natural and man-made sources. The chapters in this volume cover a wide array of topics on the biological and ecological effects of acidic precipitation. A chapter on soil productivity emphasizes changes in biological and chemical characters of forest soils impacted by acidic deposition. Additional chapters discuss specific effects on soil microorganisms, trees, and crops. The importance of aluminum in this environmental issue is highlighted by a discussion on the mobility and phytotoxicity of this element in acidic soils. This chapter puts into perspective the biology of Al stressed plants. Two major chapters discuss the effect of acidic precipitation on forest ecosystems; one emphasizing North America, and the other Europe. Effects of soil acidification on key soil processes, including litter decomposition and depletion of essential plant nutrients in the soil profile are emphasized. Finally, three major chapters comprehensively cover limnological ecosystems and their response to acidic perturbation. These chapters discuss the response of stream and lake communities, both floral and faunal, to water acidification, including reduced biodiversity in these systems. Ten chapters have been processed separately for inclusion in the appropriate data bases.

Adriano, D.C.; Johnson, A.H. (eds.)

1989-01-01

117

Infectious disease ecology: Effects of ecosystems on disease and of disease on ecosystems: A Review  

E-print Network

think) to do so. It is this innate curiosity that drives us. ALAN BERRYMAN, Medical Lake, Washington INFECTIOUS DISEASE ECOLOGY: EFFECTS OF ECO- SYSTEMS ON DISEASE AND OF DISEASE ON ECOSYS- TEMS. Based on a conference held in Millbrook, New York, May.... Infectious disease ecology is a "hot" field, with many research initiatives and funding programs now focused on the subject. In many ways, it can be seen as the field of ecology opening its eyes and extending its view to the part of the ecological world...

Peterson, A. Townsend

2009-11-01

118

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

119

Ecological effects of small-scale cutting of Philippine mangrove forests  

E-print Network

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

Walters, Bradley B.

120

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

121

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

PubMed Central

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

Hartfield, Matthew; Glémin, Sylvain

2014-01-01

122

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...

123

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

EPA Science Inventory

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

124

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...

125

Under the radar: mitigating enigmatic ecological impacts.  

PubMed

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

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

2014-11-01

126

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

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

127

Flow effects on benthic stream invertebrates and ecological processes  

NASA Astrophysics Data System (ADS)

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

Koprivsek, Maja; Brilly, Mitja

2010-05-01

128

Climate Change Has Cascading Ecological Effects on Mountain Ecosystems  

NASA Astrophysics Data System (ADS)

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

Fagre, D. B.

2007-12-01

129

Cascading climate effects and related ecological consequences during past centuries  

NASA Astrophysics Data System (ADS)

The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using structural equation analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea - Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within great tit populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and productivity on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the structural equation model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, productivity and consequently, tit population fluctuations with minima during the "Maunder Minimum" (∼ 1650-1720) and the Little Ice Age Type Event I (1810-1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, the impact of the NAO and NCP has contributed to an unprecedented increase of the population. A verification of the structural equation model against two independent data series (1970-2000 and 1750-1900) corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large-scale climate conditions substantially affect major life history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.

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

2012-10-01

130

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. PMID:24108121

Hormoz, Sahand

2013-01-01

131

Limited dispersal, deleterious mutations and the evolution of sex  

SciTech Connect

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

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

1996-03-01

132

Prediction of the deleterious nsSNPs in ABCB transporters.  

PubMed

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

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

2006-12-22

133

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

PubMed

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

Li, Xiaoping; Zhang, Liquan

2006-09-01

134

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

135

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

Microsoft Academic Search

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

Cengiz Koç

2008-01-01

136

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

Microsoft Academic Search

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

AIMEE J. WELDON; NICK M. HADDAD

2005-01-01

137

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. PMID:44247

Glass, N R

1979-01-01

138

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

ERIC Educational Resources Information Center

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

Scott, Myrtle

1969-01-01

139

Review of Ecological Effects of Roads on Terrestrial and Aquatic Communities  

Microsoft Academic Search

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

Stephen C. Trombulak; Christopher A. Frissell

2000-01-01

140

Protective action of Citrullus colocynthis seed extracts against the deleterious effect of streptozotocin on both in vitro glucose-stimulated insulin release from rat pancreatic islets and in vivo glucose homeostasis.  

PubMed

Citrullus colocynthis extracts improve glucose homeostasis in alloxan- or streptozotocin (STZ)-induced diabetic rats. Little is known, however, regarding the protective effect of these extracts against the ?-cytotoxic action of STZ. In the present study, an H2O-methanol extract was found to suppress the inhibition of glucose-stimulated insulin secretion by STZ in rat-isolated pancreatic islets. Similarly, when an aqueous extract from Citrullus colocynthis seeds was injected daily for 21 days prior to STZ administration, the perturbation of glucose homeostasis otherwise generated by the ?-cytotoxic agent was minimized in rats. PMID:24648906

Benariba, Nabila; Bellakdhar, Wafaa; Djaziri, Rabeh; Hupkens, Emeline; Louchami, Karim; Malaisse, Willy J

2013-01-01

141

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

142

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

E-print Network

development along Oregon's coast, and ii) develop a general conceptual framework of physical and biological these interactions? 4) Can we prioritize important ecological issues (e.g., key interactions)? 5) What studies Shores Conservation Coalition; Maurice Hill, Mineral Management Service; Justin Klure, Oregon Wave Energy

Wright, Dawn Jeannine

143

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

144

Evolution of prey in ecological time reduces the effect size of predators in experimental microcosms.  

PubMed

Ecologists have long studied the effect of predators on prey population abundance while evolutionary biologists have measured prey trait evolution in response to predation. Ecological and evolutionary processes were generally thought to occur on different time scales, but recent evidence suggests that evolution may alter the ecological effects of predation over the course of ecological experiments. We used a protozoan and its mosquito-larvae predator, naturally found in the water-filled leaves of pitcher plants, to examine the effect of prey evolution on predator-prey interactions. In experiments conducted over 12 days (approximately 50 prey generations, but less than one predator generation), we measured a decrease in the effect of mosquito larvae predators on protozoa prey populations. In a separate set of experiments, we found that the presence of predators corresponded with evolution of smaller cell size and increased population growth rate. In ecological experiments, two situations commonly occur: strong selection pressure applied by the treatment itself and discrepancies in generation times of associate species. Our results suggest that in either situation, the resulting evolutionary patterns may lead to dramatic and important changes in ecological effect size. PMID:20426322

terHorst, Casey P; Miller, Thomas E; Levitan, Don R

2010-03-01

145

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

PubMed

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

Bhattacherjee, Amrita; Mallik, Saurav; Kundu, Sudip

2015-01-01

146

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

E-print Network

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

Michel Jr., Frederick C.

147

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

E-print Network

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

Weathers, Kathleen C.

148

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

E-print Network

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

149

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

E-print Network

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

Wisenden, Brian D.

150

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

E-print Network

The ecology of infectious disease: Effects of host diversity and community composition on Lyme of human risk of exposure to Lyme- disease-bearing ticks. We tested the Dilution Effect model, which of vertebrate biodiversity and community com- position can reduce the incidence of Lyme disease. The inexorable

151

COMMUNITY ECOLOGY -ORIGINAL PAPER The effects of topdown versus bottomup control on benthic  

E-print Network

and associated increases in sea surface temperature and ocean acidification, are among the most important global be an effective strategy for restoring ecosystem structure and function and in reversing coral­ algal phaseCOMMUNITY ECOLOGY - ORIGINAL PAPER The effects of top­down versus bottom­up control on benthic

Smith, Jennifer E.

152

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

EPA Science Inventory

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

153

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

154

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

155

Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results  

Microsoft Academic Search

Hindar, K., Fleming, I. A., McGinnity, P., and Diserud, O. 2006. Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results. ? ICES Journal of Marine Science, 63: 1234e1247. Cultured salmonids are released or escape into the wild in large numbers and may make up significant proportions of wild salmonid populations in fresh- and saltwater, causing

Kjetil Hindar; Ian A. Fleming; Philip McGinnity; Ola Diserud

2006-01-01

156

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

E-print Network

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

Nacional de San Luis, Universidad

157

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

E-print Network

Pleistocene and ecological effects on continental-scale genetic differentiation in the bobcat (Lynx--remain largely unexplored for these species. Bobcats occur across North America and possess many characteristics. Thus, the data distinguished bobcats in the eastern USA from those in the western half, with no obvious

Bronikowski, Anne

158

Applied Soil Ecology 23 (2003) 165179 Effects of disturbance and ecosystem on decomposition  

E-print Network

Applied Soil Ecology 23 (2003) 165­179 Effects of disturbance and ecosystem on decomposition D chosen to represent a completely nested design with two disturbance levels nested within three ecosystems (agriculture, wetland, and forest) and ecosystems nested within three land resource regions (LRR) in North

Neher, Deborah A.

159

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

E-print Network

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

Mousseau, Timothy A.

160

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

E-print Network

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

Mousseau, Timothy A.

161

Ecological Modelling 177 (2004) 193208 Simulating the effects of wolf-elk population  

E-print Network

Ecological Modelling 177 (2004) 193­208 Simulating the effects of wolf-elk population dynamics,butitisunclearwhetherthisrepresentsatransientorpermanenteffectofwolfreintroduction.Herewepresent a wolf-elk model with human elk harvest and use it to investigate the long-term consequences of predator of carrion is shifted from reliance on winter severity and elk density to dependence on the strength of wolf

Wilmers, Chris

162

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

E-print Network

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

Vermont, University of

163

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

164

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

165

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

E-print Network

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

Jackson, Don

166

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

E-print Network

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

Fagherazzi, Sergio

167

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

ERIC Educational Resources Information Center

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

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

2010-01-01

168

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

Technology Transfer Automated Retrieval System (TEKTRAN)

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

169

Ecological Modelling 152 (2002) 205211 The effectiveness of various rabies spatial vaccination  

E-print Network

Ecological Modelling 152 (2002) 205­211 The effectiveness of various rabies spatial vaccination, periodic episodes of rabies epidemics erupt every 5­7 years despite low densities of the main reservoir species of rabies in this area. Canids in this desert are spread non-uniformly over space, with high

Bohrer, Gil

170

The Ecological Significance of Arbuscular Mycorrhizal Fungal Effects on Clonal Reproduction in Plants  

Microsoft Academic Search

The population ecology of clonal plants depends on the number and distri- bution of ramets formed during growth. Variation in clonal reproduction has previously been explained by variation in effects of abiotic resource heterogeneity and by plant ge- notypic variation. Different co-occurring species of the mutualistic arbuscular mycorrhizal fungi (AMF) have been shown to differentially alter growth traits of Prunella

R. Streitwolf-Engel; M. G. A. van der Heijden; A. Wiemken; I. R. Sanders

2001-01-01

171

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

E-print Network

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

Wu, Jianguo "Jingle"

172

GLOBAL CHANGE ECOLOGY -ORIGINAL PAPER Buffered climate change effects in a Mediterranean pine species  

E-print Network

understood. The aim of this research was to use climate and radial- growth data to explain how long-term experienced contrasting long-term growth variability. We defined four representative stand types basedGLOBAL CHANGE ECOLOGY - ORIGINAL PAPER Buffered climate change effects in a Mediterranean pine

Herrera, Carlos M.

173

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

E-print Network

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

Reynolds, John D.

174

Ecological, behavioral, and curricular interventions to prevent student problem behavior: An approach to implementing effective practices  

Microsoft Academic Search

While classroom management has been a highly researched topic in Applied Behavior Analysis, there are few empirically validated methods to effectively disseminate classroom techniques into school settings. There are three main classroom management areas that exist in the literature. These are: a) ecological factors, b) behavior principles, and c) curricular modifications. These three areas have been researched independently and in

Lindsey M Merritt

2010-01-01

175

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...

176

Effects of Feed Additives and Mixed Eimeria Species Infection on Intestinal Microbial Ecology of Broilers1  

Microsoft Academic Search

Evaluation of digestive microbial ecology is necessary to understand effects of growth-promoting feed. In the current study, the dynamics of intestinal mi- crobial communities (MC) were examined in broilers fed diets supplemented with a combination of antibiotic (bac- itracin methylene disalicylate) and ionophore (Coban 60), and diets containing 1 of 2 essential oil (EO) blends, Crina Poultry (CP) and Crina

M. E. Hume; S. Clemente-Hernandez; E. O. Oviedo-Rondon

177

Selection intensity against deleterious mutations in RNA secondary structures and rate of compensatory nucleotide substitutions.  

PubMed Central

A two-locus model of reversible mutations with compensatory fitness interactions is presented; single mutations are assumed to be deleterious but neutral in appropriate combinations. The expectation of the time of compensatory nucleotide substitutions is calculated analytically for the case of tight linkage between sites. It is shown that selection increases the substitution time dramatically when selection intensity Ns > 1, where N is the diploid population size and s the selection coefficient. Computer simulations demonstrate that recombination increases the substitution time, but the effect of recombination is small when selection is weak. The amount of linkage disequilibrium generated in the process of compensatory substitution is also investigated. It is shown that significant linkage disequilibrium is expected to be rare in natural populations. The model is applied to the mRNA secondary structure of the bicoid 3' untranslated region of Drosophila. It is concluded that average selection intensity Ns against single deleterious mutations is not likely to be much larger than 1. PMID:11560913

Innan, H; Stephan, W

2001-01-01

178

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

PubMed

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

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

2013-01-01

179

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

PubMed Central

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

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

2003-01-01

180

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

Microsoft Academic Search

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

Dean W. Boening

2000-01-01

181

Environmental and ontogenetic effects on intraspecific trait variation of a macrophyte species across five ecological scales.  

PubMed

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

Fu, Hui; Yuan, Guixiang; Zhong, Jiayou; Cao, Te; Ni, Leyi; Xie, Ping

2013-01-01

182

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

183

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

PubMed

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

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

2015-01-01

184

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

E-print Network

and organizational effects of such developments. Finally, through a combination of participant observation and inter- viewing of community leaders, an attempt will be made to determine the socioeconomic ramifications of uranium de- velopments on communities...THE SOCIOECONOMIC FFFECTS OF URANIUM DEVELOPMENT IN SOUTH TEXAS: A HUMAN ECOLOGICAL APPROACH A Thesis by PAMELA CHRIS HOPKINS Submitted to tne Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree...

Hopkins, Pamela Chris

1982-01-01

185

Sex slows down the accumulation of deleterious mutations in the homothallic fungus Aspergillus nidulans.  

PubMed Central

Coexistence of sexual and asexual reproduction within the same individual is an intriguing problem, especially when it concerns homothallic haplonts, like the fungus Aspergillus nidulans. In this fungus asexual and sexual offspring have largely identical genotypes. This genetic model organism is an ideal tool to measure possible fitness effects of sex (compared to asex) resulting from causes other than recombination. In this article we show that slightly deleterious mutations accumulate at a lower rate in the sexual pathway than in the asexual pathway. This secondary sex advantage may contribute to the persistence of sexual spores in this fungus. We propose that this advantage results from intra-organismal selection of the fittest gametes or zygotes, which is more stringent in the costly sexual pathway. PMID:12807769

Bruggeman, Judith; Debets, Alfons J M; Wijngaarden, Pieter J; deVisser, J Arjan G M; Hoekstra, Rolf F

2003-01-01

186

Journal of Applied Ecology 2003  

E-print Network

interactions within and between species. 2. Ecological interactions involving krill are of major importance, habitat selection, species interactions Journal of Applied Ecology (2003) 40, 692­702 Introduction Interactions between species influence population dynamics and cause indirect ecological effects. Tradi

Switzer, Paul

187

Sustainable ecological development reducing negative effects of road maintenance salts  

Microsoft Academic Search

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

Pranas Baltrenas; Agne Kazlauskiene

2009-01-01

188

ECOLOGICAL EFFECTS OF AEROSOL DRIFT FROM A SALTWATER COOLING SYSTEM  

EPA Science Inventory

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

189

The charcoal effect in Boreal forests: mechanisms and ecological consequences  

Microsoft Academic Search

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

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

1998-01-01

190

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

NASA Astrophysics Data System (ADS)

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

2012-02-01

191

Fitness effects of endemic malaria infections in a wild bird population: the importance of ecological structure.  

PubMed

1.?Parasites can have important effects on host populations influencing either fecundity or mortality, but understanding the magnitude of these effects in endemic host-parasite systems is challenging and requires an understanding of ecological processes affecting both host and parasite. 2.?Avian blood parasites (Haemoproteus and Plasmodium) have been much studied, but the effects of these parasites on hosts in areas where they are endemic remains poorly known. 3.?We used a multistate modelling framework to explore the effects of chronic infection with Plasmodium on survival and recapture probability in a large data set of breeding blue tits, involving 3424 individuals and 3118 infection diagnoses over nine years. 4.?We reveal strong associations between chronic malaria infection and both recapture and survival, effects that are dependent on the clade of parasite, on host traits and on the local risk of infection. 5.?Infection with Plasmodium relictum was associated with reduced recapture probability and increased survival, compared to P. circumflexum, suggesting that these parasites have differing virulence and cause different types of selection on this host. 6.?Our results suggest a large potential survival cost of acute infections revealed by modelling host survival as a function of the local risk of infection. 7.?Our analyses suggest not only that endemic avian malaria may have multiple fitness effects on their hosts and that these effects are species dependent, but also that adding ecological structure (in this case parasite species and spatial variation in disease occurrence) to analyses of host-parasite interactions is an important step in understanding the ecology and evolution of these systems. PMID:21426343

Lachish, Shelly; Knowles, Sarah C L; Alves, Ricardo; Wood, Matthew J; Sheldon, Ben C

2011-11-01

192

[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

193

The genetic effects of ecological disturbance: flooding in jumping mice.  

PubMed

Pacific jumping mice (Zapus trinotatus) live in riparian habitats that are discontinuously distributed and subject to regular flooding. Both of these characteristics have a spatial component. Habitat-restricted dispersal frequently leads to spatial genetic structure among individuals, and flooding often imposes spatially specific mortality. Here I report that following a severe flood, an interaction between these factors resulted in an immediate reduction of genetic diversity and genetic divergence of the postflood population. Survival was spatially biased toward more closely related individuals, and this was propagated throughout the postflood population by changes in reproduction. Not only did the number of closely related breeding pairs increase, but so did the production of offspring by individuals. These changes precipitated strong genetic effects, including a reduction in observed heterozygosity, an increase in relatedness, a doubling of inbreeding levels, and significant genetic divergence from previous years. PMID:19929316

Vignieri, Sacha N

2010-01-01

194

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

SciTech Connect

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

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

1988-09-01

195

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

PubMed

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

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

2010-09-01

196

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

197

Ecological bias in studies of the short-term effects of air pollution on health  

NASA Astrophysics Data System (ADS)

There has been a great deal of research into the short-term effects of air pollution on health with a large number of studies modelling the association between aggregate disease counts and environmental exposures measured at point locations, for example via air pollution monitors. In such cases, the standard approach is to average the observed measurements from the individual monitors and use this in a log-linear health model. Hence such studies are ecological in nature being based on spatially aggregated health and exposure data. Here we investigate the potential for bias in the estimates of the effects on health when estimating the short-term effects of air pollution on health. Such ecological bias may occur if a simple summary measure, such as a daily mean, is not a suitable summary of a spatially variable pollution surface. We assess the performance of commonly used models when confronted with such issues using simulation studies and compare their performance with a model specifically designed to acknowledge the effects of exposure aggregation. In addition to simulation studies, we apply the models to a case study of the short-term effects of particulate matter on respiratory mortality using data from Greater London for the period 2002-2005. We found a significant increased risk of 3% (95% CI 1-5%) associated with the average of the previous three days exposure to particulate matter (per 10 ?g m-3 PM10).

Shaddick, Gavin; Lee, Duncan; Wakefield, Jonathan

2013-06-01

198

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

PubMed

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

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

2012-01-01

199

Ecological thresholds: a survey  

Microsoft Academic Search

The existence of ecological discontinuities and thresholds has been recognised by ecological economics as a key feature to take into account in the study of environment–economy interactions. This paper reviews some theoretical developments and empirical studies dealing with ecological phenomena involving non-linear dynamics. The literature about this issue reveals that there is abundant evidence of discontinuities and threshold effects as

Roldan Muradian

2001-01-01

200

Ecology 2007 21, 408421  

E-print Network

& Moriuchi 2005), the evolution of host­parasite interactions (Wade 1998), speciation (e.g. via host­race Ecological Society Blackwell Publishing Ltd Maternal effects and evolution at ecological time-scales K for evolution at ecological time-scales. 2. Despite an increased interest in the prevalence, composition

Nussey, Dan

201

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.

202

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. PMID:24307670

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

2014-01-01

203

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

PubMed

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

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

2015-01-23

204

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

205

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

PubMed

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

Berger, Joel

2007-08-01

206

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

207

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

208

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

209

Evolution in response to direct and indirect ecological effects in pitcher plant inquiline communities.  

PubMed

Ecologists have long recognized the importance of indirect ecological effects on species abundances, coexistence, and diversity. However, the evolutionary consequences of indirect interactions are rarely considered. Here I conduct selection experiments and examine the evolutionary response of Colpoda sp., a ciliated protozoan, to other members of the inquiline community of purple pitcher plants (Sarracenia purpurea). I measured the evolution of six traits in response to (1) predation by mosquito larvae, (2) competition from other ciliated protozoans, and (3) simultaneous predation and competition. The latter treatment incorporated both direct effects and indirect effects due to interactions between predators and competitors. Population growth rate and cell size evolved in response to direct effects of predators and competitors. However, trait values in the multispecies treatment were similar to those in the monoculture treatment, indicating that direct effects were offset by strong indirect effects on the evolution of traits. For most of the traits measured, indirect effects were opposed to, and often stronger than, direct effects. These indirect effects occurred as a result of behavioral changes of the predator in the presence of competitors and as a result of reduced densities of competitors in the presence of predators. Incorporating indirect effects provides a more realistic description of how species evolve in complex natural communities. PMID:20955011

terHorst, Casey P

2010-12-01

210

Effect of the ecological water conveyance project on environment in the Lower Tarim River, Xinjiang, China.  

PubMed

The dynamic response of groundwater level is examined in traverse and lengthways directions. Take the Yinsu section for an example, we have simulated groundwater levels before and after water-conveyance every time and calculated the incidence of groundwater on the both sides of the river. It is noted that the effect keeps growing with the water-delivery times increasing, from 570 m after the first times to 3,334 m after the eighth times. In addition, this paper involves the temporal response of the natural vegetation to water conveyance, vegetation coverage, planted-species number, dominant position and species diversity from 2002 to 2006. The findings indicate that the positive influence of ecological water conveyance project (EWCP) on the ecosystem in the Lower Tarim River is a long-term process. In this paper, we try to calculate water required for recovery of damaged ecosystem by using data available. This project is likely the base of research on water demand and the reference of measures for research on ecological water conveyance effect. PMID:18274873

Ye, Zhaoxia; Chen, Yaning; Li, Weihong; Yan, Yan

2009-02-01

211

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

USGS Publications Warehouse

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

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

2005-01-01

212

Interaction modification effects on ecological networks are affected by ratio dependence and network topology.  

PubMed

Interaction modification (IM), where one species modifies the strength of the density-mediated direct interaction between two other species, is an important ecological process, but little is known about the collective effect of multiple IM on overall community dynamics. We use stochastic bioenergetic modelling of ecological networks with different network topologies, functional responses and parameter values, to investigate the effects of IM connectance and IM strength on ecosystem properties including the evenness of species abundances and variability of system biomass. We found that the maximum system biomass that could potentially be attained by the model systems increased with IM connectance and strength when the models had nonrandom topology and prey-dependent functional responses as opposed to random topology and ratio-dependent responses. The maximum potential species evenness increased with IM strength but decreased with increasing IM connectance, when all modifications were negative. These findings underscore the importance of accounting for multiple IM across the community for understanding complex community dynamics. PMID:25167789

Lin, Yangchen; Sutherland, William J

2014-12-21

213

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. Urbanization influences stream morphology more than any other land use (Douglas, 2011): it alters hydrology and sediment inputs leading to deepening and widening of streams (Chin, 2006). Concomitantly, urbanization often directly impairs stream morphology through channel and riparian zone interventions, e.g., culverts (Hawley et al., 2012), rock protection (Vietz et al., 2012b), and constricted floodplains (Gurnell et al., 2007). These changes to channel geomorphology in turn contribute to poor in-stream ecological condition (Morley and Karr, 2002; Walsh et al., 2005b; Gurnell et al., 2007; Elosegi et al., 2010).The common conception is that channels undergo gross morphologic alterations if > 10-20% of their watershed is covered by impervious surfaces (total imperviousness, TI; Bledsoe and Watson, 2001; Chin, 2006; Table 1). Many of these studies may, however, underestimate the influence of urbanization by using insensitive channel metrics and assessing streams in early stages of urbanization. Most importantly, TI, as a measure of urban density, may not adequately represent the way in which urbanization alters the master variables of flow and sediment within a watershed.Hydrologists have long recognized that, rather than the proportion of impervious cover within a watershed, it is the proportion that is directly connected to the stream through stormwater drainage systems that may be a better predictor of urban-induced hydrologic change (Leopold, 1968). Referred to as effective imperviousness (EI) the proportion of impervious cover directly connected to the stream through stormwater drainage systems may also be a better predictor of geomorphic response than is TI. Over the last decade a direct measure of EI has been found to be a better predictor of ecological response in urban streams (Walsh et al., 2012), but use of such a metric has not found its way into geomorphic studies even though TI has been found to be ineffective (e.g., Bledsoe et al.,

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

2014-02-01

214

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

PubMed Central

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

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

2014-01-01

215

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

SciTech Connect

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

Preston, R

2011-03-14

216

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

E-print Network

: ozone; air pollution; forest productivity; NPP; tree growth; modeling; forest canopy; photosynthesisEcological Applications, Scott V. Ollinger et al. Ozone Effects on Forest Productivity 7(4), 1997, pp. 1237-1251 1 SIMULATING OZONE EFFECTS ON FOREST PRODUCTIVITY: INTERACTIONS AMONG LEAF-, CANOPY

New Hampshire, University of

217

SYNTHESIS Scale-dependent effect sizes of ecological drivers on biodiversity: why standardised sampling is not enough  

E-print Network

of biodiversity loss are highly variable (Murphy & Romanuk (2012) and often controversial, including effectsREVIEW AND SYNTHESIS Scale-dependent effect sizes of ecological drivers on biodiversity: why standardised sampling is not enough Jonathan M. Chase1 * and Tiffany M. Knight2 1 Biodiversity Synthesis

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. PMID:24782886

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

2014-01-01

220

An adjustment of benthic ecological quality assessment to effects of salinity.  

PubMed

In the last decade a politically inspired marine protection movement arose in the European Union. This movement leads to an holistic strategy. Merging the Water Framework Directive (WFD) and the Marine Strategy Directive (MSD) along the European coastline demands sophisticated ecological classification procedures. The 'Benthic Quality Index' (BQI) is one of several indices created in view of the WFD. We used the dynamic species reference system ES(50)(0.05) to test the capability of BQI to exclude primary environmental factors including the salinity gradient and depth (a proxy for the oxygen regime) from the ecological quality (EcoQ) assessment. A macrozoobenthos dataset of the southern Baltic Sea spreading over more than 20 years and over 100,000 km2 was used for the EcoQ assessment. Quality assurance rules were applied to the record set and an analytical dataset of 936 sampling events with 20,451 abundance records was used in the analysis. We show that the natural salinity gradient has a severe impact on the BQI based EcoQ. We adapted the calculation procedure to reduce the salinity effects to a minimum. According to the adaptation 503 sensitivity/tolerance values for 87 species were computed. These values were calculated within seven salinity ranges from 0 to >30 PSU and two depth zones. These values can be used as a reference for further investigation in the Baltic and other areas with similar environmental conditions. PMID:19084875

Fleischer, Dirk; Zettler, Michael L

2009-08-01

221

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

222

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

PubMed Central

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

Juliano, Steven A.; Lounibos, L. Philip

2007-01-01

223

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

PubMed

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

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

2014-11-19

224

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

225

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

PubMed

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

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

2013-01-10

226

Ecology 2001 15, 772781  

E-print Network

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

Janzen, Fredric

227

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

228

[The effect of thermal power plant on microbial ecology and environmental quality].  

PubMed

To investigate the effect of thermal power plant on the microbial ecology and the environmental quality, the Hsieh-Ho Thermal Power Plant was chosen and the populations of microbes including bacteria, actinomycetes, fungi, and cellulolytic, phosphate-solubilizing and nitrogen-fixing microbes were selected as the parameters of microbial ecology. The pH values of the soil sample collected from inside and outside of the plant were 5.2-6.2 and 4.0-5.3, respectively. Moisture content in plant area was lower than that in the surrounding area. Microbial populations of the topsoils were higher than those of the subsoils. Each gram of soil contained 3.64 x 10(4)-5.16 x 10(7) colonies of bacteria, 1.75 x 10(3)-1.10 x 10(6) colonies of actinomycetes and 6.72 x 10(3)-8.78 x 10(6) colonies of fungi in the plant area; while they were 5.52 x 10(4)-2.14 x 10(7), 8.26 x 10(3)-7.25 x 10(5) and 3.49 x 10(3)-2.74 x 10(6) colonies of bacteria, actinomycetes and fungi, respectively, in the surrounding area. The effect of seasonal change on microbial populations was not significant. The ratio of cellulolytic, phosphate-solubilizing and nitrogen-fixing microbes to the total count in the plant area was also higher than that in the surrounding area, and some of them had significant differences. From the statistical analysis, the effect of thermal power generator on the population and distribution of microbes was significantly different. PMID:10650492

Yang, S S; Yang, C K; Chang, E H; Wei, C B

1999-12-01

229

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

230

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

231

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

232

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

PubMed

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

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

2011-12-15

233

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

Microsoft Academic Search

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

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

2011-01-01

234

Testing the ecological stability of ectomycorrhizal symbiosis: effects of heat, ash and mycorrhizal colonization on Pinus muricata seedling performance  

Microsoft Academic Search

Understanding how abiotic conditions medi- atetheoutcomeofbioticinteractionsisakeyquestionin community ecology. This is particularly interesting in the case of mutualisms because changingenvironmental conditionsmaybeasourceofevolutionaryorecological instability in the relationship between symbiotic part- ners. For the mycorrhizal symbiosis, elevated nutrient levels may make the carbon cost to plants of supporting mycorrhizal fungi outweigh the benefits of mycorrhizal nutrient acquisition. In this study, we simulated the effects

Kabir G. Peay; Thomas D. Bruns; Matteo Garbelotto

2009-01-01

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

The effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats) in Idaho and northwestern Utah  

E-print Network

-tailed woodrat (Neotoma cinerea), at five locations within south central Idaho and northwestern Utah. Previous; Body mass; Species replacement; Neotoma lepida; Neotoma cinerea; Late Quaternary; Global warmingThe effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats

237

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

SciTech Connect

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

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

1994-09-01

238

Z .Forest Ecology and Management 105 1998 197207 The effect of Kalmia angustifolia on the growth, nutrition, and  

E-print Network

Z .Forest Ecology and Management 105 1998 197­207 The effect of Kalmia angustifolia on the growth laboratory research has suggested that allelochemicals of K. angustifolia affect the Z .growth and development of black spruce as well as the growth of certain ectomycorrhizal ECM fungi associated with black Z

Egger, Keith N.

239

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

240

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

EPA Science Inventory

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

241

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

SciTech Connect

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

Not Available

1980-11-01

242

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

PubMed Central

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 km2 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

2013-01-01

243

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

SciTech Connect

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

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

1995-12-31

244

Human Ecology Human ecology Research  

E-print Network

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

Wang, Z. Jane

245

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

246

Association between protective and deleterious HLA alleles with multiple sclerosis in Central East Sardinia.  

PubMed

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. PMID:19654877

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

247

The Effect of Inappropriate Calibration: Three Case Studies in Molecular Ecology  

Microsoft Academic Search

Time-scales estimated from sequence data play an important role in molecular ecology. They can be used to draw correlations between evolutionary and palaeoclimatic events, to measure the tempo of speciation, and to study the demographic history of an endangered species. In all of these studies, it is paramount to have accurate estimates of time- scales and substitution rates. Molecular ecological

Simon Y. W. Ho; Urmas Saarma; Ross Barnett; James Haile; Beth Shapiro

2008-01-01

248

The effect of taxonomic resolution on the assessment of ecological water quality classes  

Microsoft Academic Search

Within the ecological assessment of running waters based on benthic macroinvertebrates different levels of taxonomic resolution (species, genus, family and higher) are in use. Although assessment systems are often developed with detailed data on species level, water managers and other end-users could like to use data on higher taxonomic levels to assess the ecological quality of a water body because

Astrid Schmidt-Kloiber; Rebi C. Nijboer

2004-01-01

249

Plant treatment, pollutant load, and soil type effects in rhizosphere ecology of trace element polluted soils.  

PubMed

Re-vegetation of trace element contaminated soils can alter the pH and chelating capacity in the rhizosphere, increasing the mobility of pollutants, which, in turn, may impact on rhizosphere ecology. In this study a short-term pot experiment was carried out in order to investigate the multi-factorial effects of: buffering capacity (sandy-loam and loam soils); pollutant load (0%, 1.3%, and 4% of pyrite sludge), and the presence/absence of plant (Lolium perenne L. and Medicago sativa L.) on the mobility of trace elements, soil biochemical functionality (hydrolase activities), and biological diversity (bacterial and nematode communities). The experiment was carried out with representative soils from the Guadiamar basin (SW Spain), an area where the Aznalcóllar mining spill affected over 4000ha. Results indicated that the development of rhizospheres in polluted soils (coarse-textured) increases the mobilization of trace elements. In general the presence of roots has stimulatory effects on soil quality indicators such as hydrolase activities and both bacterial and nematode communities. However, the presence of high amount of metals interferes with these beneficial effects. This study provided evidence about the complexity of the impact of growing plants on trace element polluted soils. Trace element mobilization, hydrolase activities and bacterial and nematode communities in the rhizosphere are dependent on plant species, soil type, and pollution dose. PMID:20385407

Belén Hinojosa, M; Carreira, José A; García-Ruíz, Roberto; Rodríguez-Maroto, José M; Daniell, Tim J; Griffiths, Bryan S

2010-07-01

250

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. PMID:20974978

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

2010-01-01

251

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

EPA Science Inventory

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

252

Accumulation of slightly deleterious mutations in mitochondrial protein-coding genes of  

E-print Network

Accumulation of slightly deleterious mutations in mitochondrial protein-coding genes of large and can reach fixation. Here we investigate this phenomenon for a set of all 13 mitochondrial protein-coding genes from 110 mammalian species. By using body mass as a proxy for Ne, we show that large mammals (i

Sorenson, Michael

253

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

Microsoft Academic Search

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

ALEXEY S. KONDRASHOV

254

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

E-print Network

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

Behmer, Spencer T.

255

Prediction of solvent accessibility and sites of deleterious mutations from protein sequence  

E-print Network

Prediction of solvent accessibility and sites of deleterious mutations from protein sequence of deleteriousmutationshavepreviouslybeenidentified by stability measurement or functional assay. Of the total of 130 residues predicted as sites of computational biology. Currently, reliable 3D prediction is still limited to the proteins with sig- nificant

Weston, Ken

256

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. PMID:23536817

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

2013-01-01

257

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

PubMed

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

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

2006-05-19

258

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

PubMed

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

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

2014-10-21

259

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

PubMed Central

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

2014-01-01

260

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

261

Studying pretrial publicity effects: new methods for improving ecological validity and testing external validity.  

PubMed

Although research examining the effects of pretrial publicity (PTP) on individuals' appraisals of a defendant and verdict decision making generally has been found to be internally valid, the external validity has been questioned by some social scientists as well as lawyers and judges. It is often proposed that the verisimilitude (or ecological validity) ofthe research should be increased in the service of increasing external validity; however, increasing verisimilitude can be costly in terms of both time and money. It is proposed that the Internet is a viable means of conducting PTP research that allows high verisimilitude without high costs. This is demonstrated with a study in which we used the Internet to examine PTP effects in an actual trial as it was taking place. Successful use of the Internet to conduct experimental research in other areas of psychology and law is discussed, as well as the importance of future research examining whether independent variables interact with methods in ways that undermine the generalizability of research findings. PMID:11868618

Studebaker, Christina A; Robbennolt, Jennifer K; Penrod, Steven D; Pathak-Sharma, Maithilee K; Groscup, Jennifer L; Devenport, Jennifer L

2002-02-01

262

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

PubMed

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

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

2013-12-01

263

Integrating fundamental concepts of ecology, biogeography, and sampling into effective ecological niche modeling and species distribution modeling  

E-print Network

, see below). The literature taking advantage of this novel analytical functionality has increased massively (Figure 1), and two book-length syntheses have now appeared (Franklin 2010, Peterson et al. 2011). Two recent papers have seen massive... was easy to implement. Niche modeling, however, has seen the opposite evolutionary trajectory: tools that, in effect, estimate niches have been around for decades (Nix 1986, Austin et al. 1990, Stockwell and Noble 1992), yet a conceptual framework...

Peterson, A. Townsend; Soberó n, Jorge

2012-10-30

264

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...

265

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

Microsoft Academic Search

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

Richard T. T. Forman; Robert D. Deblinger

2000-01-01

266

Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level  

NASA Astrophysics Data System (ADS)

Coastal hypoxia and anoxia have become a global key stressor to marine ecosystems, with almost 500 dead zones recorded wordwide. By triggering cascading effects from the individual organism to the community and ecosystem-level, oxygen depletions threat marine biodiversity and can alter ecosystem structure and function. By integrating both physiological function and ecological processes, animal behaviour is ideal for assessing the stress state of benthic macrofauna to low dissolved oxygen. The initial response of organisms can serve as an early-warning signal, while the successive behavioural reactions of key species indicate hypoxia levels and help assess community degradation. Here we document the behavioural responses of a representative spectrum of benthic macrofauna in the natural setting in the Northern Adriatic Sea, Mediterranean. We experimentally induced small-scale anoxia with a benthic chamber in 24 m depth to overcome the difficulties in predicting the onset of hypoxia, which often hinders full documentation in the field. The behavioural reactions were documented with a time-lapse camera. Oxygen depletion elicited significant and repeatable changes in general (visibility, locomotion, body movement and posture, location) and species-specific reactions in virtually all organisms (302 individuals from 32 species and 2 species groups). Most atypical (stress) behaviours were associated with specific oxygen thresholds: arm-tipping in the ophiuroid Ophiothrix quinquemaculata, for example, with the onset of mild hypoxia (< 2 mL O2 L-1), the emergence of polychates on the sediment surface with moderate hypoxia (< 1 mL O2 L-1), the emergence of the infaunal sea urchin Schizaster canaliferus on the sediment with severe hypoxia (< 0.5 mL O2 L-1) and heavy body rotations in sea anemones with anoxia. Other species changed their activity patterns, i.e. circadian rhythm in the hermit crab Paguristes eremita or the bioherm-associated crab Pisidia longimana. Intra- and interspecific reactions were weakened or changed: decapods ceased defensive and territorial behaviour, and predator-prey interactions and relationships shifted. This nuanced scale of resolution is a useful tool to interpret present benthic community status (behaviour) and past mortalities (community composition, e.g. survival of tolerant species). This information on the sensitivity (onset of stress response), tolerance (mortality, survival), and characteristics (i.e. life habit, functional role) of key species also helps predict potential future changes in benthic structure and ecosystem functioning. This integrated approach can transport complex ecological processes to the public and decision-makers and help define specific monitoring, assessment and conservation plans.

Riedel, B.; Pados, T.; Pretterebner, K.; Schiemer, L.; Steckbauer, A.; Haselmair, A.; Zuschin, M.; Stachowitsch, M.

2013-08-01

267

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

268

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

NASA Technical Reports Server (NTRS)

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

Swanson, F. J.

1988-01-01

269

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

SciTech Connect

The 1984 Hazardous and Solid Waste Amendments to the Resource Conservation and Recovery Act (RCRA) required assessment of all current and former solid waste management units. Following guidelines under RCRA and the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), a remedial investigation (RI) was required of the Y-12 Plant for their filled coal ash pond (FCAP) and associated areas on McCoy Branch. The RI process was initiated and assessments were presented. Because the disposal of coal ash in the ash pond, McCoy Branch, and Rogers Quarry was not consistent with the Tennessee Water Quality Act, several remediation steps were implemented between 1986 and 1994 for McCoy Branch to address disposal problems. The required ecological risk assessments of McCoy Branch watershed included provisions for biological monitoring of the watershed. The objectives of the biological monitoring were to (1) document changes in biological quality of McCoy Branch after completion of a pipeline bypassing upper McCoy Branch and further, after termination of all discharges to Rogers Quarry, (2) provide guidance on the need for additional remediation, and (3) evaluate the effectiveness of implemented remedial actions. The data from the biological monitoring program may also determine whether the goals of protection of human health and the environment of McCoy Branch are being accomplished.

Ryon, M.G. [ed.] [ed.

1996-09-01

270

The Effect of Taxonomic Resolution on the Assessment of Ecological Water Quality Classes  

Microsoft Academic Search

\\u000a Within the ecological assessment of running waters based on benthic macroinvertebrates different levels of taxonomic resolution\\u000a (species, genus, family and higher) are in use. Although assessment systems are often developed with detailed data on species\\u000a level, water managers and other end-users could like to use data on higher taxonomic levels to assess the ecological quality\\u000a of a water body because

Astrid Schmidt-Kloiber; Rebi C. Nijboer

271

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

272

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

PubMed

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

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

2014-02-01

273

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. PMID:18587609

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

2009-01-01

274

[Effects of nutrient and light on seedlings morphological plasticity of four Saussurea species with different ecological breadth].  

PubMed

Taking four Saussurea species with different ecological breadth in the eastern Qinghai-Tibetan Plateau as test materials, their seedlings relative growth rate (RGR), root mass to shoot mass ratio (R/S), and specific leaf area (SLA) were determined under different nutrient and light treatments. The results showed that nutrient and light had significant effects on the seedlings RGR, R/S and SLA of the four Saussurea species, and there existed a certain interactive effect between nutrient and light. The plasticity of these morphological characteristics and their response patterns to the variation of nutrient and light conditions varied with species. Significant interactive effects (P < 0.001) between light, nutrient, and species were observed on the R/S and SLA of Saussurea. For the four Saussurea species, the mean phenotypic plasticity index of their seedlings was positively correlated with their ecological distribution, being the highest (0.71) for S. japonica, the best widespread species in the four species. The morphological plasticity of Saussurea species was positively related to their distribution ecological breadth. PMID:18975746

Wu, Gao-lin; Chen, Min; Du, Guo-zhen

2008-08-01

275

EXPERIMENTAL MARINE MICROCOSM TEST PROTOCOL AND SUPPORT DOCUMENT. MEASUREMENT OF THE ECOLOGICAL EFFECTS, FATE AND TRANSPORT OF CHEMICALS IN A SITE-SPECIFIC MARINE ECOSYSTEM  

EPA Science Inventory

Experimental microcosms designed to simulate major physical, chemical and biological complexities of site specific, coastal marine ecosystems are described. Procedures are presented which enable the investigator to determine the fate, ecological effects and transport for 'new' an...

276

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

PubMed

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

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

2003-06-01

277

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

PubMed Central

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

2014-01-01

278

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

279

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

280

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. PMID:21738425

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

2011-01-01

281

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

PubMed

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

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

2011-01-01

282

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

PubMed Central

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

2013-01-01

283

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

284

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

USGS Publications Warehouse

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

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

1984-01-01

285

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. PMID:25567890

Wang, Hui-Yu; Höök, Tomas O

2009-01-01

286

[Effect of temperature on proteinase activities of enteral microbiota and intestinal mucosa of fish of different ecological group].  

PubMed

Effect of temperature on proteinases activities of enteral microbiota and of intestinal mucosa was studied in five fish species (roach Rutilus rutilus, crucian carp Carassius carassius, common perch Perca fluviatilis, pike-perch Zander lucioperca, and pike Esox lucius) belonging by the nutrition type to different ecological groups. Essential differences of temperature characteristics of proteinases of intestinal mucosa and of enteral microbiota are revealed in fish belonging by the nutrition type to different ecologic groups. The character of the t0-function of proteinases of intestinal mucosa and enteral microbiota by casein and hemoglobin as a rule is different. The highest values of relative proteinases activities for casein in the zone of low temperatures (38 and 45.3 % of the maximal activity) are found at study of proteinases of enteral microbiota in common perch and crucian carp. The latter indicates a significant adaptability of the enteral microbiota proteinases of common perch and crucial carp to functioning at low temperatures. PMID:22645973

Kuz'mina, V V; Shalygin, M V; Skvortsova, E G

2012-01-01

287

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

288

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

PubMed

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

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

2009-01-01

289

Ecological Misconceptions.  

ERIC Educational Resources Information Center

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

Munson, Bruce H.

1994-01-01

290

Backyard Ecology.  

ERIC Educational Resources Information Center

Describes the Ecology Explorers, the community education component of Arizona State University's Central Arizona Phoenix Long-Term Ecological Research project, which offers teacher internship programs that link university researchers, K-12 teachers, and students in studying urban ecology. Explains that student neighborhoods are dynamic ecosystems…

Elser, Monica; Musheno, Birgit; Saltz, Charlene

2003-01-01

291

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.

2007-01-01

292

Effects of Changes in Lugu Lake Water Quality on Schizothorax Yunnansis Ecological Habitat Based on HABITAT Model  

NASA Astrophysics Data System (ADS)

Schizothorax Yunnansis is an unique fish species only existing in Lugu Lake, which is located in the southwestern China. The simulation and research on Schizothorax Yunnansis habitat environment have a vital significance to protect this rare fish. With the development of the tourism industry, there bring more pressure on the environmental protection. The living environment of Schizothorax Yunnansis is destroyed seriously because the water quality is suffering the sustaining pollution of domestic sewage from the peripheral villages. This paper analyzes the relationship between water quality change and Schizothorax Yunnansis ecological habitat and evalutes Schizothorax Yunnansis's ecological habitat impact based on HABITAT model. The results show that when the TP concentration in Lugu Lake does not exceed Schizothorax Yunnansis's survival threshold, Schizothorax Yunnansis can get more nutrients and the suitable habitat area for itself is increased. Conversely, it can lead to TP toxicity in the Schizothorax Yunnansis and even death. Therefore, unsuitable habitat area for Schizothorax Yunnansis is increased. It can be seen from the results that HABITAT model can assist in ecological impact assessment studies by translating results of hydrological, water quality models into effects on the natural environment and human society.

Huang, Wei; Mynnet, Arthur

293

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...

294

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

E-print Network

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

Chapman, Lauren J.

295

Ecology of the phytoplankton of the River Moselle: effects of disturbances on community structure and diversity  

Microsoft Academic Search

A data set on community composition of the phytoplankton of the River Moselle (France) has been used for testing the ‘intermediate disturbance hypothesis’ (IDH). After a short presentation of the ecology of the river and of its phytoplankton, the main changes in composition and diversity of the suspended algal assemblage are described. It is emphasized that discharge fluctuations, related to

J.-P. Descy

1993-01-01

296

Carnivore Repatriation and Holarctic Prey: Narrowing the Deficit in Ecological Effectiveness  

Microsoft Academic Search

The continuing global decline of large carnivores has catalyzed great interest in reintroduction to restore populations and to reestablish ecologically functional relationships. I used variation in the distribution of four Holarctic prey species and their behavior as proxies to investigate the pace and intensity by which responses are lost or reinvigorated by carnivore repatriation. By simulating the presence of wolves

JOEL BERGER

2007-01-01

297

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

NASA Astrophysics Data System (ADS)

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.

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

298

The Prospective Function of Curcumin Against the Negative Effects of Microgravity  

NASA Astrophysics Data System (ADS)

Microgravity has several deleterious effects on cells. These cells may exhibit an up-regulation or down-regulation of their gene expression. We are investigating the effects of the phytochemical curcumin on microgravity-induced deleterious effects.

Lewis, A.; Johnson, P.; Jejelowo, O. A.; Sodipe, A.; Shishodia, S.

2010-04-01

299

[Venous ecology].  

PubMed

The purpose of venous ecology is to study the effect of the environment on the peripheral vessels. It is very extensive but still little explored subject in need of multidisciplinary study. The author reviews some of the major problems of ecophlebology: --pollution and harmful effects of urban life (atmospheric pollution, stress and influence of noise on the vessels); --the influence of habitat (furniture, ergonomics, urbanism, sociological studies and under-floor heating); --the cites new research on terrestrial electro-magnettism, meteoropathology, biological clocks and the influence of the mass media. In conclusion he hopes that ecophlebology will be the object of research which will permit a better understanding, and hence better control, of the pathological mechanisms resulting from the environment. PMID:928510

Reinharez, D

1977-01-01

300

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

301

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. PMID:24860643

2014-01-01

302

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

PubMed

We have developed a novel structure-based evaluation for missense variants that explicitly models protein structure and amino acid properties to predict the likelihood that a variant disrupts protein function. A structural disruption score (SDS) is introduced as a measure to depict the likelihood that a case variant is functional. The score is constructed using characteristics that distinguish between causal and neutral variants within a group of proteins. The SDS score is correlated with standard sequence-based deleteriousness, but shows promise for improving discrimination between neutral and causal variants at less conserved sites. The prediction was performed on 3-dimentional structures of 57 gene products whose homozygous SNPs were identified as case-exclusive variants in an exome sequencing study of epilepsy disorders. We contrasted the candidate epilepsy variants with scores for likely benign variants found in the EVS database, and for positive control variants in the same genes that are suspected to promote a range of diseases. To derive a characteristic profile of damaging SNPs, we transformed continuous scores into categorical variables based on the score distribution of each measurement, collected from all possible SNPs in this protein set, where extreme measures were assumed to be deleterious. A second epilepsy dataset was used to replicate the findings. Causal variants tend to receive higher sequence-based deleterious scores, induce larger physico-chemical changes between amino acid pairs, locate in protein domains, buried sites or on conserved protein surface clusters, and cause protein destabilization, relative to negative controls. These measures were agglomerated for each variant. A list of nine high-priority putative functional variants for epilepsy was generated. Our newly developed SDS protocol facilitates SNP prioritization for experimental validation. PMID:24795746

Preeprem, Thanawadee; Gibson, Greg

2014-01-01

303

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

304

A selective sweep on a deleterious mutation in the CPT1A gene in Arctic populations  

E-print Network

1    A selective sweep on a deleterious mutation in the CPT1A gene in Arctic populations   Florian J. Clemente1,18, Alexia Cardona1,18,*, Charlotte E. Inchley1, Benjamin M. Peter2, Guy  Jacobs3,4, Luca Pagani1, Daniel J. Lawson5, Tiago Antão6... intake is low 4. The extent to which the c.1436C>T mutation contributes to disorders associated with CPT1 deficiency such as hypoketotic hypoglycemia and sudden infant death syndrome is still unclear. The derived allele has been reported as being...

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

2014-10-23

305

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

306

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

307

Forest ecology Introduction  

E-print Network

Forest ecology Introduction Forest ecology is a part of ecology that is con- cerned with forests ecology, population ecology, community ecology, and ecosystem ecology. Forest ecology has generally focused on forest trees so it could provide the ecological basis for silviculture, forest management

Johnson, Edward A.

308

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

309

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

310

Ecological effects of lawn greens with pure and mixed stands in an urban setting  

Microsoft Academic Search

We studied the ecological benefits of four types of urban green spaces (lawn, a Robinia pseudoacacia stand, a Pinus tabulaeformis stand and a mixed stand of both species) in Yuan Dynasty Wall Relics Park, Beijing. Each of the eight sampling sites was\\u000a about 0.1 hm2. The experiment was carried out in June, 2006 over a period of eight consecutive days,

Jiaomei Liu; Shuhua Li; Zhiguo Zhang

2008-01-01

311

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

ERIC Educational Resources Information Center

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

Hamilton-Ekeke, Joy-Telu

2007-01-01

312

The Effect of Inappropriate Calibration: Three Case Studies in Molecular Ecology  

E-print Network

Time-scales estimated from sequence data play an important role in molecular ecology. They can be used to draw correlations between evolutionary and palaeoclimatic events, to measure the tempo of speciation, and to study the demographic history of an endangered species. In all of these studies, it is paramount to have accurate estimates of timescales and substitution rates. Molecular ecological studies typically focus on intraspecific data that have evolved on genealogical scales, but often these studies inappropriately employ deep fossil calibrations or canonical substitution rates (e.g., 1 % per million years for birds and mammals) for calibrating estimates of divergence times. These approaches can yield misleading estimates of molecular time-scales, with significant impacts on subsequent evolutionary and ecological inferences. We illustrate this calibration problem using three case studies: avian speciation in the late Pleistocene, the demographic history of bowhead whales, and the Pleistocene biogeography of brown bears. For each data set, we compare the date estimates that are obtained using internal and external calibration points. In all three cases, the conclusions are significantly altered by the application of revised, internally-calibrated substitution rates. Collectively, the results emphasise

Simon Y. W. Ho; Urmas Saarma; Ross Barnett; James Haile; Beth Shapiro

2008-01-01

313

The Effect of Inappropriate Calibration: Three Case Studies in Molecular Ecology  

PubMed Central

Time-scales estimated from sequence data play an important role in molecular ecology. They can be used to draw correlations between evolutionary and palaeoclimatic events, to measure the tempo of speciation, and to study the demographic history of an endangered species. In all of these studies, it is paramount to have accurate estimates of time-scales and substitution rates. Molecular ecological studies typically focus on intraspecific data that have evolved on genealogical scales, but often these studies inappropriately employ deep fossil calibrations or canonical substitution rates (e.g., 1% per million years for birds and mammals) for calibrating estimates of divergence times. These approaches can yield misleading estimates of molecular time-scales, with significant impacts on subsequent evolutionary and ecological inferences. We illustrate this calibration problem using three case studies: avian speciation in the late Pleistocene, the demographic history of bowhead whales, and the Pleistocene biogeography of brown bears. For each data set, we compare the date estimates that are obtained using internal and external calibration points. In all three cases, the conclusions are significantly altered by the application of revised, internally-calibrated substitution rates. Collectively, the results emphasise the importance of judicious selection of calibrations for analyses of recent evolutionary events. PMID:18286172

Ho, Simon Y. W.; Saarma, Urmas; Barnett, Ross; Haile, James; Shapiro, Beth

2008-01-01

314

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

315

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

SciTech Connect

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

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

1981-05-01

316

Cumulative effects of restoration efforts on ecological characteristics of an open water area within the Upper Mississippi River  

USGS Publications Warehouse

Ecological restoration efforts in large rivers generally aim to ameliorate ecological effects associated with large-scale modification of those rivers. This study examined whether the effects of restoration efforts-specifically those of island construction-within a largely open water restoration area of the Upper Mississippi River (UMR) might be seen at the spatial scale of that 3476ha area. The cumulative effects of island construction, when observed over multiple years, were postulated to have made the restoration area increasingly similar to a positive reference area (a proximate area comprising contiguous backwater areas) and increasingly different from two negative reference areas. The negative reference areas represented the Mississippi River main channel in an area proximate to the restoration area and an open water area in a related Mississippi River reach that has seen relatively little restoration effort. Inferences on the effects of restoration were made by comparing constrained and unconstrained models of summer chlorophyll a (CHL), summer inorganic suspended solids (ISS) and counts of benthic mayfly larvae. Constrained models forced trends in means or in both means and sampling variances to become, over time, increasingly similar to those in the positive reference area and increasingly dissimilar to those in the negative reference areas. Trends were estimated over 12- (mayflies) or 14-year sampling periods, and were evaluated using model information criteria. Based on these methods, restoration effects were observed for CHL and mayflies while evidence in favour of restoration effects on ISS was equivocal. These findings suggest that the cumulative effects of island building at relatively large spatial scales within large rivers may be estimated using data from large-scale surveillance monitoring programs. Published in 2010 by John Wiley & Sons, Ltd.

Gray, B.R.; Shi, W.; Houser, J.N.; Rogala, J.T.; Guan, Z.; Cochran-Biederman, J. L.

2011-01-01

317

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

318

General Ecology  

NSDL National Science Digital Library

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

319

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

320

Predictive ecology: systems approaches  

PubMed Central

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

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

2012-01-01

321

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

NSDL National Science Digital Library

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

Nancy Beuhner (Deubrook Area Schools)

2008-08-01

322

Common sex-linked deleterious alleles in a plant parasitic fungus alter infection success but show no pleiotropic advantage.  

PubMed

Microbotryum violaceum is a fungus that causes the sterilizing anther smut disease in Caryophyllaceae. Its diploid teliospores normally produce equal proportions of haploid sporidia of its two mating types. However natural populations contain high frequencies of individuals producing sporidia of only one mating type ('biased strains'). This mating type-ratio bias is caused by deleterious alleles at haploid phase ('haplo-lethals') linked to the mating type locus that can be transmitted only by intra-tetrad selfing. We used experimental inoculations to test some of the hypotheses proposed to explain the maintenance of haplo-lethals. We found a disadvantage of biased strains in infection ability and high intra-tetrad mating rates. Biased strains had no higher competitive ability nor shorter latency and their higher spore production per flower appeared insufficient to compensate their disadvantages. These findings were only consistent with the hypothesis that haplo-lethals are maintained under a metapopulation structure because of high intra-tetrad selfing rates, founder effects and selection at the population level. PMID:16674592

Giraud, T; Jonot, O; Shykoff, J A

2006-05-01

323

Terrestrial ecology  

Microsoft Academic Search

Terrestrial studies continue to contribute ideas and ecological data ; relevant to nuclear-power plant siting and the management of stored radioactive ; wastes in the semi-arid steppe region of Washington. These ideas and data are ; also largely applicable to steppe regions of Oregon, Idaho, and Nevada. Much of ; the available information concerning the ecology of steppe ecosystems has

1974-01-01

324

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

325

Soil Ecology  

NASA Astrophysics Data System (ADS)

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

Killham, Ken

1994-04-01

326

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

PubMed

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

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

2014-04-15

327

Deleterious mutations at the mitochondrial ND3 gene in South American marsh rats (Holochilus).  

PubMed

Statistical analyses of DNA sequences have revealed patterns of nonneutral evolution in mitochondrial DNA of mice, humans, and Drosophila. Here we report patterns of mitochondrial sequence evolution in South American marsh rats (genus Holochilus). We sequenced the complete mitochondrial ND3 gene in 82 Holochilus brasiliensis and 21 H. vulpinus to test the neutral prediction that the ratio of nonsynonymous to synonymous nucleotide changes is the same within and between species. Within H. brasiliensis we observed a greater number of amino acid polymorphisms than expected based on interspecific comparisons. This contingency table analysis suggests that many amino acid polymorphisms are mildly deleterious. Several tests of the frequency distribution also revealed departures from a neutral, equilibrium model, and these departures were observed for both nonsynonymous and synonymous sites. In general, an excess of rare sites was observed, consistent with either a recent selective sweep or with populations not at mutation-drift equilibrium. PMID:9725852

Kennedy, P; Nachman, M W

1998-09-01

328

Deleterious mutations at the mitochondrial ND3 gene in South American marsh rats (Holochilus).  

PubMed Central

Statistical analyses of DNA sequences have revealed patterns of nonneutral evolution in mitochondrial DNA of mice, humans, and Drosophila. Here we report patterns of mitochondrial sequence evolution in South American marsh rats (genus Holochilus). We sequenced the complete mitochondrial ND3 gene in 82 Holochilus brasiliensis and 21 H. vulpinus to test the neutral prediction that the ratio of nonsynonymous to synonymous nucleotide changes is the same within and between species. Within H. brasiliensis we observed a greater number of amino acid polymorphisms than expected based on interspecific comparisons. This contingency table analysis suggests that many amino acid polymorphisms are mildly deleterious. Several tests of the frequency distribution also revealed departures from a neutral, equilibrium model, and these departures were observed for both nonsynonymous and synonymous sites. In general, an excess of rare sites was observed, consistent with either a recent selective sweep or with populations not at mutation-drift equilibrium. PMID:9725852

Kennedy, P; Nachman, M W

1998-01-01

329

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

PubMed

We applied constrained ordination numerical ecology methods to data produced with a human intestinal tract-specific phylogenetic microarray (the Aus-HIT Chip) to examine the microbial diversity associated with matched biopsy tissue samples taken from the caecum, transverse colon, sigmoid colon and rectum of 10 healthy patients. Consistent with previous studies, the profiles revealed a marked intersubject variability; however, the numerical ecology methods of analysis allowed the subtraction of the subject effect from the data and revealed, for the first time, evidence of a longitudinal gradient for specific microbes along the colorectum. In particular, probes targeting Streptococcus and Enterococcus spp. produced strongest signals with caecal and transverse colon samples, with a gradual decline through to the rectum. Conversely, the analyses suggest that several members of the Enterobacteriaceae increase in relative abundance towards the rectum. These collective differences were substantiated by the multivariate analysis of quantitative PCR data. We were also able to identify differences in the microarray profiles, especially for the streptococci and Faecalibacterium prausnitzii, on the basis of gender. The results derived by these multivariate analyses are biologically intuitive and suggest that the biogeography of the colonic mucosa can be monitored for changes through cross-sectional and/or inception cohort studies. PMID:21124491

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

2011-05-01

330

The Effects of Local Ecological Knowledge, Minimum-Impact Knowledge, and Prior Experience on Visitor Perceptions of the Ecological Impacts of Backcountry Recreation  

NASA Astrophysics Data System (ADS)

An on-site visitor survey instrument was developed to examine visitor perceptions of resource impacts resulting from backcountry hiking activities. The survey was conducted in the Bear Lake Corridor of Rocky Mountain National Park, CO and examined visitor characteristics that may influence visitor perceptions of specific resource conditions. Findings indicate that visitors are more perceptive of recreation-related resource impacts that are the result of undesirable behavior and, while visitors do perceive resource impacts, visitors tend to be more affected by crowding. Factors such as local ecological knowledge and knowledge of minimal-impact practices positively influence visitor perceptions of resource impacts. These findings support the use of visitor education on ecological knowledge and minimum-impact as a means of increasing visitor awareness of recreation impact issues.

D'Antonio, Ashley; Monz, Christopher; Newman, Peter; Lawson, Steve; Taff, Derrick

2012-10-01

331

The effects of local ecological knowledge, minimum-impact knowledge, and prior experience on visitor perceptions of the ecological impacts of backcountry recreation.  

PubMed

An on-site visitor survey instrument was developed to examine visitor perceptions of resource impacts resulting from backcountry hiking activities. The survey was conducted in the Bear Lake Corridor of Rocky Mountain National Park, CO and examined visitor characteristics that may influence visitor perceptions of specific resource conditions. Findings indicate that visitors are more perceptive of recreation-related resource impacts that are the result of undesirable behavior and, while visitors do perceive resource impacts, visitors tend to be more affected by crowding. Factors such as local ecological knowledge and knowledge of minimal-impact practices positively influence visitor perceptions of resource impacts. These findings support the use of visitor education on ecological knowledge and minimum-impact as a means of increasing visitor awareness of recreation impact issues. PMID:22814546

D'Antonio, Ashley; Monz, Christopher; Newman, Peter; Lawson, Steve; Taff, Derrick

2012-10-01

332

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

333

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

PubMed

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 population 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. Documenation of the spread of oil and its biological begun immediately. Intertidal mangroves, 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. PMID:17780421

Jackson, J B; Cubit, J D; Keller, B D; Batista, V; Burns, K; Caffey, H M; Caldwell, R L; Garrity, S D; Getter, C D; Gonzalez, C; Guzman, H M; Kaufmann, K W; Knap, A H; Levings, S C; Marshall, M J; Steger, R; Thompson, R C; Weil, E

1989-01-01

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 11 days. 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

Deleterious effects of fungizone on growth hormone and prolactin secretion by cultured GH 3 cells  

Microsoft Academic Search

Summary  The rates at which growth hormone (GH) and prolactin (PRL) are spontaneously secreted from a rat pituitary tumor cell line\\u000a (GH3) were significantly reduced when these cells were maintained in medium containing 2.5 ?g\\/ml Fungizone (Fz). The reduction\\u000a in hormone secretion was not immediately reversed by removal of Fz during perifusion, but after 3 wk in control medium, secretory\\u000a rates

C. A. Lapp; J. M. Tyler; M. E. Stachura; Y. S. Lee

1987-01-01

336

Deleterious Effects of Amyloid ? Oligomers Acting as an Extracellular Scaffold for mGluR5  

PubMed Central

SUMMARY Soluble oligomers of amyloid ? (A?) play a role in the memory impairment characteristic of Alzheimer’s disease. Acting as pathogenic ligands, A? oligomers bind to particular synapses and perturb their function, morphology, and maintenance. Events that occur shortly after oligomer binding have been investigated here in live hippocampal neurons by single particle tracking of quantum dot-labeled oligomers and synaptic proteins. Membrane-attached oligomers initially move freely, but their diffusion is hindered markedly upon accumulation at synapses. Concomitantly, individual metabotropic glutamate receptors (mGluR5) manifest strikingly reduced lateral diffusion as they become aberrantly clustered. This clustering of mGluR5 elevates intracellular calcium and causes synapse deterioration, responses prevented by an mGluR5 antagonist. As expected, clustering by artificial crosslinking also promotes synaptotoxicity. These results reveal a mechanism whereby A? oligomers induce the abnormal accumulation and overstabilization of a glutamate receptor, thus providing a mechanistic and molecular basis for A? oligomer-induced early synaptic failure. PMID:20547131

Renner, Marianne; Lacor, Pascale N.; Velasco, Pauline T.; Xu, Jian; Contractor, Anis; Klein, William L.; Triller, Antoine

2011-01-01

337

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

NASA Technical Reports Server (NTRS)

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

Moran, Robert P.

2013-01-01

338

Arterial Elastance and Wave Reflection Augmentation of Systolic Blood Pressure: Deleterious Effects and Implications for Therapy  

Microsoft Academic Search

Systolic and pulse blood pressures are stronger predictors of stroke, coronary heart disease, myocardial infarction, heart failure, end-stage renal disease, and cardiovascular mortality than diastolic pressure. Furthermore, diastolic pressure is inversely related to coronary heart disease and cardiovascular mortality. Increased elastance (or stiffness, inverse of compliance) of the central elastic arteries is the primary cause of increased systolic and pulse

Wilmer W. Nichols; David G. Edwards

2001-01-01

339

The deleterious effect of contrast reversal on recognition is unique to faces, not objects  

E-print Network

Nederhouser a , Xiaomin Yue a , Michael C. Mangini b , Irving Biederman a,* a Department of Psychology, non-face objects (Galper, 1970; Subramaniam & Biederman, 1997). Could this be a function of stimulus-accidental specification of orientation and depth discontinuities (Biederman, 1987; Kobatake & Tanaka, 1994) or surface

Biederman, Irving

340

Nitric oxide mediates prostaglandins' deleterious effect on lipopolysaccharide-triggered murine fetal resorption  

PubMed Central

Genital tract bacterial infections could induce abortion and are some of the most common complications of pregnancy; however, the mechanisms remain unclear. We investigated the role of prostaglandins (PGs) in the mechanism of bacterial lipopolysaccharide (LPS)-induced pregnancy loss in a mouse model, and we hypothesized that PGs might play a central role in this action. LPS increased PG production in the uterus and decidua from early pregnant mice and stimulated cyclooxygenase (COX)-II mRNA and protein expression in the decidua but not in the uterus. We also observed that COX inhibitors prevented embryonic resorption (ER). To study the possible interaction between nitric oxide (NO) and PGs, we administered aminoguanidine, an inducible NO synthase inhibitor. NO inhibited basal PGE and PGF2? production in the decidua but activated their uterine synthesis and COX-II mRNA expression under septic conditions. A NO donor (S-nitroso-N-acetylpenicillamine) produced 100% ER and increased PG levels in the uterus and decidua. LPS-stimulated protein nitration was higher in the uterus than in the decidua. Quercetin, a peroxynitrite scavenger, did not reverse LPS-induced ER. Our results suggest that in a model of septic abortion characterized by increased PG levels, NO might nitrate and thus inhibit COX catalytic activity. ER prevention by COX inhibitors adds a possible clinical application to early pregnancy complications due to infections. PMID:17460035

Aisemberg, J.; Vercelli, C.; Billi, S.; Ribeiro, M. L.; Ogando, D.; Meiss, R.; McCann, S. M.; Rettori, V.; Franchi, A. M.

2007-01-01

341

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

NASA Technical Reports Server (NTRS)

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

Moran, Robert P.

2013-01-01

342

Deleterious effects of neuronal accumulation of glycogen in flies and mice.  

PubMed

Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. PMID:22549942

Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

2012-08-01

343

Deleterious effects of neuronal accumulation of glycogen in flies and mice  

PubMed Central

Under physiological conditions, most neurons keep glycogen synthase (GS) in an inactive form and do not show detectable levels of glycogen. Nevertheless, aberrant glycogen accumulation in neurons is a hallmark of patients suffering from Lafora disease or other polyglucosan disorders. Although these diseases are associated with mutations in genes involved in glycogen metabolism, the role of glycogen accumulation remains elusive. Here, we generated mouse and fly models expressing an active form of GS to force neuronal accumulation of glycogen. We present evidence that the progressive accumulation of glycogen in mouse and Drosophila neurons leads to neuronal loss, locomotion defects and reduced lifespan. Our results highlight glycogen accumulation in neurons as a direct cause of neurodegeneration. PMID:22549942

Duran, Jordi; Tevy, María Florencia; Garcia-Rocha, Mar; Calbó, Joaquim; Milán, Marco; Guinovart, Joan J

2012-01-01

344

The Deleterious Effect of Red Blood Cell Storage on Microvascular Response to Transfusion  

PubMed Central

Background The transfusion of relatively older red blood cells (RBCs) has been associated with both morbidity and mortality in trauma patients in observational studies. Although the mechanisms responsible for this phenomenon remain unclear, alterations in the microcirculation as a result of the transfusion of relatively older blood may be a causative factor. To assess this hypothesis, we evaluated microvascular perfusion in trauma patients during RBC transfusion. Methods Anemic but otherwise stable trauma ICU patients with orders for transfusion were identified. Thenar muscle tissue oxygen saturation (StO2) was measured continuously by near infrared spectroscopy during the course of transfusion of one RBC unit. Sublingual microcirculation was observed by sidestream dark field illumination microscopy before and after transfusion of one RBC unit. Thenar muscle StO2 was recorded over the course of transfusion. Pre- and post-transfusion perfused capillary vascular density (PCD) was determined by semi-quantitative image analysis. Changes in StO2 and PCD relative to age of RBC unit were evaluated using mixed models that adjusted for baseline StO2 and Spearman's correlation, respectively. Results Overall, 93 patients were recruited for study participation, 69% were male and average Injury Severity Score was 26.4. Average pre-transfusion hemoglobin was 7.5 mg/dL and the average age of RBC unit transfused was 29.4 days. Average peri-transfusion StO2 was negatively associated with increasing RBC age (slope -0.11, p = 0.0014). Change in PCD from pre- to post-transfusion was found to correlate negatively with RBC storage age (Spearman correlation = -0.27, p = 0.037). Conclusions The transfusion of relatively older RBC units was associated with a decline in both StO2 and PCD. Collectively, these observations demonstrate that transfusions of older RBC units are associated with the inhibition of regional microvascular perfusion. In patients requiring multiple units of RBCs, alteration of the microcirculation by relatively older units could potentially contribute to adverse outcomes. Level of Evidence: II, prognostic study PMID:24158198

Weinberg, Jordan A.; MacLennan, Paul A.; Vandromme–Cusick, Marianne J.; Magnotti, Louis J.; Kerby, Jeffrey D.; Rue, Loring W.; Angotti, Jonathan M.; Garrett, Cristen A.; Hendrick, Leah E.; Croce, Martin A.; Fabian, Timothy C.; Barnum, Scott R.; Patel, Rakesh P.

2013-01-01

345

Ecology 2007 95, 517529  

E-print Network

Ecological Society Blackwell Publishing Ltd Lake-effect snow as the dominant control of mesic on forest communities. Lake-effect snow produces a three-fold gradient in annual snowfall over tens and Evolutionary Biology, Department of Plant Biology and Department of Geology, University of Illinois, Urbana IL

Hu, Feng Sheng

346

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

347

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

348

Urban Ecology  

NSDL National Science Digital Library

When people think about the concept and idea of ecology, they may not immediately picture a bustling urban street or a network of interconnected bike paths. Since 1975, a group of architects and activists have been thinking about exactly those things in terms of urban ecology (and a good deal more to boot), coupling it with a conviction that urban ecology can draw on ecology, public participation and urban planning "to help design and build healthier cities." Given these ideas, it seems logical that this organization has its roots in the Bay Area, and continues to offer up interesting plans and proposals, many of which can be found on the website. One such document is the Walkable Streets Toolkit, which is designed for use by communities that seek to make their streets more pedestrian friendly. Additionally, visitors will want to look at current and past editions of The Urban Ecologist, which is the group's quarterly newsletter.

349

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.

350

Warfare Ecology  

Microsoft Academic Search

\\u000a Among human activities causing ecological change, war is both intensive and far-reaching. Yet environmental research related\\u000a to warfare is limited in depth and fragmented by discipline. Here we (1) outline a field of study called “warfare ecology,”\\u000a (2) provide a taxonomy of warfare useful for organizing the field, (3) review empirical studies, and (4) propose research\\u000a directions and policy implications

Gary E. Machlis; Thor Hanson

351

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.

National Wildlife Federation

352

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

353

The Ecological Impact of Biofuels  

E-print Network

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

Kammen, Daniel M.

354

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

PubMed Central

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

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

2008-01-01

355

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. PMID:24628394

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

2014-08-01

356

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

357

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

358

ASSSOCIATION BETWEEN LOCI WITH DELETERIOUS ALLELES AND DISTORTED SEX RATIOS IN AN INBRED LINE OF TILAPIA (OREOCHOMIS AUREUS)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Three microsatellite markers (UNH159, UNH231, and UNH216) were examined for association with both deleterious genes and sex ratio distortions in a full-sib family of 222 progeny from the fourth generation of a meiogynogenetic tilapia line (Oreochromis aureus). The three markers previously were mappe...

359

Chemical Modulation of Mutant mGlu1 Receptors Derived from Deleterious GRM1 Mutations Found in Schizophrenics  

PubMed Central

Schizophrenia is a complex and highly heterogeneous psychiatric disorder whose precise etiology remains elusive. While genome-wide association studies (GWAS) have identified risk genes, they have failed to determine if rare coding single nucleotide polymorphisms (nsSNPs) contribute in schizophrenia. Recently, two independent studies identified 12 rare, deleterious nsSNPS in the GRM1 gene, which encodes the metabotropic glutamate receptor subtype 1 (mGlu1), in schizophrenic patients. Here, we generated stable cell lines expressing the mGlu1 mutant receptors and assessed their pharmacology. Using both the endogenous agonist glutamate and the synthetic agonist DHPG, we found that several of the mutant mGlu1 receptors displayed a loss of function that was not due to a loss in plasma membrane expression. Due to a lack of mGlu1 positive allosteric modulators (PAM) tool compounds active at human mGlu1, we optimized a known mGlu4 PAM/mGlu1 NAM chemotype into a series of potent and selective mGlu1 PAMs by virtue of a double “molecular switch”. Employing mGlu1 PAMs from multiple chemotypes, we demonstrate that the mutant receptors can be potentiated by small molecules and in some cases efficacy restored to that comparable to wild type mGlu1 receptors, suggesting deficits in patients with schizophrenia due to these mutations may be amenable to intervention with an mGlu1 PAM. However, in wild type animals, mGlu1 negative allosteric modulators (NAMs) are efficacious in classic models predictive of antipsychotic activity, whereas we show that mGlu1 PAMs have no effect to slight potentiation in these models. These data further highlight the heterogeneity of schizophrenia and the critical role of patient selection strategies in psychiatric clinical trials to match genotype with therapeutic mechanism. PMID:25137254

2014-01-01

360

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

361

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

PubMed

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

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

2014-10-23

362

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

PubMed Central

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

Hughes, Austin L.

2012-01-01

363

Tattoo inks contain polycyclic aromatic hydrocarbons that additionally generate deleterious singlet oxygen.  

PubMed

In the past years, tattoos have become very popular worldwide, and millions of people have tattoos with mainly black colours. Black tattoo inks are usually based on soot, are not regulated and may contain hazardous polycyclic aromatic hydrocarbons (PAHs). Part of PAHs possibly stay lifelong in skin, absorb UV radiation and generate singlet oxygen, which may affect skin integrity. Therefore, we analysed 19 commercially available tattoo inks using HPLC and mass spectrometry. The total concentrations of PAHs in the different inks ranged from 0.14 to 201 microg/g tattoo ink. Benz(a)pyrene was found in four ink samples at a mean concentration of 0.3 +/- 0.2 microg/g. We also found high concentrations of phenol ranging from 0.2 to 385 microg/g tattoo ink. PAHs partly show high quantum yields of singlet oxygen (Phi(Delta)) in the range from 0.18 to 0.85. We incubated keratinocytes with extracts of different inks. Subsequent UVA irradiation decreased the mitochondrial activity of cells when the extracts contained PAHs, which sufficiently absorb UVA and show simultaneously high Phi(Delta) value. Tattooing with black inks entails an injection of substantial amounts of phenol and PAHs into skin. Most of these PAHs are carcinogenic and may additionally generate deleterious singlet oxygen inside the dermis when skin is exposed to UVA (e.g. solar radiation). PMID:20545755

Regensburger, Johannes; Lehner, Karin; Maisch, Tim; Vasold, Rudolf; Santarelli, Francesco; Engel, Eva; Gollmer, Anita; König, Burkhard; Landthaler, Michael; Bäumler, Wolfgang

2010-08-01

364

Compliance to a Cell Phone-Based Ecological Momentary Assessment Study: The Effect of Time and Personality Characteristics  

ERIC Educational Resources Information Center

Ecological momentary assessment (EMA) is a method that is now widely used to study behavior and mood in the settings in which they naturally occur. It maximizes ecological validity and avoids the limitations of retrospective self-reports. Compliance patterns across time have not been studied. Consistent compliance patterns could lead to data not…

Courvoisier, Delphine S.; Eid, Michael; Lischetzke, Tanja

2012-01-01

365

Discriminating between deleterious and neutral non-frameshifting indels based on protein interaction networks and hybrid properties.  

PubMed

More than ten thousand coding variants are contained in each human genome; however, our knowledge of the way genetic variants underlie phenotypic differences is far from complete. Small insertions and deletions (indels) are one of the most common types of human genetic variants, and indels play a significant role in human inherited disease. To date, we still lack a comprehensive understanding of how indels cause diseases. Therefore, identification and analysis of such deleterious variants is a key challenge and has been of great interest in the current research in genome biology. Increasing numbers of computational methods have been developed for discriminating between deleterious indels and neutral indels. However, most of the existing methods are based on traditional sequential or structural features, which cannot completely explain the association between indels and the resulting induced inherited disease. In this study, we establish a novel method to predict deleterious non-frameshifting indels based on features extracted from both protein interaction networks and traditional hybrid properties. Each indel was coded by 1,246 features. Using the maximum relevance minimum redundancy method and the incremental feature selection method, we obtained an optimal feature set containing 42 features, of which 21 features were derived from protein interaction networks. Based on the optimal feature set, an 88 % accuracy and a 0.76 MCC value were achieved by a Random Forest as evaluated by the Jackknife cross-validation test. This method outperformed existing methods of predicting deleterious indels, and can be applied in practice for deleterious non-frameshifting indel predictions in genome research. The analysis of the optimal features selected in the model revealed that network interactions play more important roles and could be informative for better illustrating an indel's function and disease associations than traditional sequential or structural features. These results could shed some light on the genetic basis of human genetic variations and human inherited diseases. PMID:25248637

Zhang, Ning; Huang, Tao; Cai, Yu-Dong

2015-02-01

366

Ontogenetic patterns in bluefish (Pomatomus saltatrix) feeding ecology and the effect on mercury biomagnification.  

PubMed

In this study, bluefish (Pomatomus saltatrix; age 0-7, n?=?632) and their prey (forage fish, macroinvertebrates, zooplankton; n?=?2,005) were collected from the Narragansett Bay estuary (RI, USA), and total Hg concentration was measured in white muscle and whole-body tissues, respectively. Bluefish Hg concentrations were analyzed relative to fish length, prey Hg content, and ontogenetic shifts in habitat use and foraging ecology, the latter assessed using stomach content analysis (n?=?711) and stable nitrogen (?(15)N) and carbon (?(13)C) isotope measurements (n?=?360). Diet and ?(13)C analysis showed that age 0 bluefish consumed both benthic and pelagic prey (silversides, sand shrimp, planktonic crustaceans; ?(13)C?=?-?16.52‰), whereas age 1?+ bluefish fed almost exclusively on pelagic forage fish (Atlantic menhaden, herring; ?(13)C?=?-?17.33‰). Bluefish total Hg concentrations were significantly correlated with length (mean Hg?=?0.041 and 0.254?ppm wet wt for age 0 and age 1?+ bluefish, respectively). Furthermore, Hg biomagnification rates were maximal during bluefish early life stages and decelerated over time, resulting in relatively high Hg concentrations in age 0 fish. Rapid Hg accumulation in age 0 bluefish is attributed to these individuals occupying a comparable trophic level to age 1?+ bluefish (?(15)N?=?15.58 and 16.09‰; trophic level?=?3.55 and 3.71 for age 0 and age 1?+ bluefish, respectively), as well as juveniles having greater standardized consumption rates of Hg-contaminated prey. Finally, bluefish larger than 30?cm total length consistently had Hg levels above the U.S. Environmental Protection Agency criterion of 0.3?ppm. As such, frequent consumption of bluefish could pose a human health risk, and preferentially consuming smaller bluefish may be an inadequate strategy for minimizing human dietary exposure to Hg. PMID:21381087

Szczebak, Joseph T; Taylor, David L

2011-06-01

367

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. PMID:20941329

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

2010-01-01

368

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

PubMed Central

Whereas the El Niño Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet. PMID:14561270

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

2003-01-01

369

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

370

Stimulatory effects of tannins and cholic acid on tryptic hydrolysis of proteins: Ecological implications  

Microsoft Academic Search

The biochemical basis for considering tannins as digestion inhibitors has been reexamined. Both stimulatory and inhibitory effects of tannins on tryptic hydrolysis are reported. We show how stimulation may result from tannin-induced structural changes in the substrate protein, effectively denaturing it. The surfactant and bile constituent cholic acid also produced similar stimulatory effects. These results have considerable implications for normal

Simon Mole; Peter G. Waterman

1985-01-01

371

Designing for ecology : the ecological park  

E-print Network

This thesis aims to define a) what an ecological park is, and b) whether it is a new model in park design. Reference to the literature on landscape ecology is used to analyze the natural ecological merit of these parks, ...

Power, Andres M

2006-01-01

372

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

PubMed

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

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

2013-08-01

373

Ecology 2002 90, 9891001  

E-print Network

(estimated from seed fragments), undigested and viable in germination trials were determined. 3 Ingestion on germinability. Both the presence of seeds in the diet and the effects of gut passage showed high interspecific, germination rate, germination speed, gut structure, seed dispersal, seed germination Journal of Ecology (2002

Green, Andy J.

374

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. PMID:23227226

Yokoya, Masana; Shimizu, Hideyasu; Higuchi, Yukito

2012-01-01

375

Bayesian mixed-effects location and scale models for multivariate longitudinal outcomes: an application to ecological momentary assessment data.  

PubMed

In the statistical literature, the methods to understand the relationship of explanatory variables on each individual outcome variable are well developed and widely applied. However, in most health-related studies given the technological advancement and sophisticated methods of obtaining and storing data, a need to perform joint analysis of multivariate outcomes while explaining the impact of predictors simultaneously and accounting for all the correlations is in high demand. In this manuscript, we propose a generalized approach within a Bayesian framework that models the changes in the variation in terms of explanatory variables and captures the correlations between the multivariate continuous outcomes by the inclusion of random effects at both the location and scale levels. We describe the use of a spherical transformation for the correlations between the random location and scale effects in order to apply separation strategy for prior elicitation while ensuring positive semi-definiteness of the covariance matrix. We present the details of our approach using an example from an ecological momentary assessment study on adolescents. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25409923

Kapur, Kush; Li, Xue; Blood, Emily A; Hedeker, Donald

2015-02-20

376

Towards a synthesis of frameworks in nutritional ecology: interacting effects of protein, carbohydrate and phosphorus on field cricket fitness.  

PubMed

Phosphorus has been identified as an important determinant of nutrition-related biological variation. The macronutrients protein (P) and carbohydrates (C), both alone and interactively, are known to affect animal performance. No study, however, has investigated the importance of phosphorus relative to dietary protein or carbohydrates, or the interactive effects of phosphorus with these macronutrients, on fitness-related traits in animals. We used a nutritional geometry framework to address this question in adult field crickets (Gryllus veletis). Our results showed that lifespan, weight gain, acoustic mate signalling and egg production were maximized on diets with different P : C ratios, that phosphorus did not positively affect any of these fitness traits, and that males and females had different optimal macronutrient intake ratios for reproductive performance. When given a choice, crickets selected diets that maximized both lifespan and reproductive performance by preferentially eating diets with low P : C ratios, and females selected diets with a higher P : C ratio than males. Conversely, phosphorus intake was not regulated. Overall, our findings highlight the importance of disentangling the influences of different nutrients, and of quantifying both their individual and interactive effects, on animal fitness traits, so as to gain a more integrative understanding of their nutritional ecology. PMID:25143029

Harrison, Sarah J; Raubenheimer, David; Simpson, Stephen J; Godin, Jean-Guy J; Bertram, Susan M

2014-10-01

377

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

PubMed

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

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

2015-01-01

378

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

PubMed Central

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

Hoefer, Dirk; Hammer, Timo R.

2011-01-01

379

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

SciTech Connect

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

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

1999-04-01

380

Ecological Effects of Macroalgal Harvesting on Beaches in the Peel-Harvey Estuary, Western Australia  

Microsoft Academic Search

Macrophyte harvesting is used to manage macroalgal accumulations in eutrophic estuaries throughout the world. Despite the widespread use of harvesting as a management tool, little research has addressed the effects on beach ecosystems. This paper reports on experimental investigations into the short- and long-term effects of macroalgal harvesting on beaches in the Peel-Harvey estuarine system, Western Australia. The short-term effects

P. Lavery; S Bootle; M Vanderklift

1999-01-01

381

Plant Ecology An Introduction  

E-print Network

1 Plant Ecology An Introduction Ecology as a Science Study of the relationships between living and causes of the abundance and distribution of organisms Ecology as a Science We'll use the perspective of terrestrial plants Basic ecology - ecological principles Applied ecology - application of principles

Cochran-Stafira, D. Liane

382

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

PubMed

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

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

2009-09-01

383

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

PubMed

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

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

2008-02-21

384

Ecological effects of feral biofuel crops in constructed oak savannah communities - June 2012  

EPA Science Inventory

The effects of elevated temperatures and drought on constructed oak savannahs were studied to determine the interactive effects of potentially invasive feral biofuel species and climate change on native grassland communities. A total of 12 sunlit mesocosm were used. Each mesoco...

385

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

E-print Network

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

386

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

387

Ecological Heterogeneity in the Effects of Grazing and Fire on Grassland Diversity  

Microsoft Academic Search

Grazing and fire and are major forces shaping patterns of native and exotic species diversity in many grasslands, yet both of these disturbances have notoriously variable effects. Few studies have examined how landscape-level heterogeneity in grassland characteristics, such as soil-based variation in biomass and species composition, may contribute to variation in the effects of fire or grazing. We studied the

S. Harrison; B. D. Inouye; H. D. Safford

2003-01-01

388

Conservation Ecology & Entomology Department Stellenbosch University ecological network research (Mondi  

E-print Network

Conservation Ecology & Entomology Department Stellenbosch University ecological network research (Mondi Ecological Network Programme (MENP) Ecological networks (ENs) reduce the isolation of populations helps to prevent ecological relaxation (the loss of ecological systems and interactions) and so prevents

Geldenhuys, Jaco

389

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

PubMed Central

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

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

2014-01-01

390

The effects of exposure to environmental factors on Heart Rate Variability: an ecological perspective.  

PubMed

The impact of human exposure to environmental factors on Heart Rate Variability (HRV) was examined in the urban space of Tel-Aviv-Jaffa. Four environmental factors were investigated: thermal and social loads; CO concentrations and noise. Levels of HRV are explained mainly by subjective social stresses, noise and CO. The most interesting result is the fact that while subjective social stress and noise increase HRV, low levels of CO are reducing HRV to some extent moderating the impact of subjective social stress and noise. Beyond the poisoning effect of CO and the fact that extremely low levels of HRV associated with high dozes of CO increase risk for life, low levels of CO may have a narcotic effect, as it is measured by HRV. The effects of thermal loads on HRV are negligible probably due to the use of behavioral means in order to neutralize heat and cold effects. PMID:23477780

Schnell, Izhak; Potchter, Oded; Epstein, Yoram; Yaakov, Yaron; Hermesh, Hagai; Brenner, Shmuel; Tirosh, Emanuel

2013-12-01

391

PHYSIOLOGICAL AND CHEMICAL ECOLOGY Effect of Selenium-treated Alfalfa on Development, Survival, Feeding,  

E-print Network

, alfalfa, biomagniÃ?cation, phytoextraction, phytoremediation, se- lenium SELENIUM (SE) IS essential that cadmium (Cd) interaction with Se in the insect gut had a positive effect (up to 2 g/g Se) on Mada- gascar

Trumble, John T.

392

Effects of stream topology on ecological community results from neutral models  

EPA Science Inventory

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

393

GROUP REPORT: PHYSIOLOGICAL AND ECOLOGICAL EFFECTS OF ACIDIFICATION ON AQUATIC BIOTA  

EPA Science Inventory

Acidification affects all components of biological communities in lakes and streams: microbes, algae, macrophytes, invertebrates, fish, amphibians, and other vertebrates that rely on aquatic ecosystems for habitat or food. echanisms of effect are both direct (toxic responses to c...

394

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 ...

395

Ecological Effects of Spring and Late Summer Applications of Lambda-Cyhalothrin on Freshwater Microcosms  

Microsoft Academic Search

The aim of the study was to compare the effects of the pyrethroid insecticide lambda-cyhalothrin (treated at 10, 25, 50, 100,\\u000a 250 ng active ingredient a.i.\\/L) on a drainage ditch ecosystem in spring and late summer. Microcosms (water volume approximately\\u000a 430 L) were established using enclosures in a 50-cm–deep experimental ditch system containing communities typical of macrophyte-dominated\\u000a freshwater ecosystems. Effects

R. P. A. Van Wijngaarden; T. C. M. Brock; P. J. van den Brink; R. Gylstra; S. J. Maund

2006-01-01

396

Defending Ecology.  

ERIC Educational Resources Information Center

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

Margolis, Brian

2000-01-01

397

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

398

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

399

Biodegradation of Dichlorodiphenyltrichloroethanes (DDTs) and Hexachlorocyclohexanes (HCHs) with Plant and Nutrients and Their Effects on the Microbial Ecological Kinetics.  

PubMed

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

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

2015-02-01

400

Testing the ecological stability of ectomycorrhizal symbiosis: effects of heat, ash and mycorrhizal colonization on Pinus muricata seedling performance  

Microsoft Academic Search

Understanding how abiotic conditions mediate the outcome of biotic interactions is a key question in community ecology. This\\u000a is particularly interesting in the case of mutualisms because changing environmental conditions may be a source of evolutionary\\u000a or ecological instability in the relationship between symbiotic partners. For the mycorrhizal symbiosis, elevated nutrient\\u000a levels may make the carbon cost to plants of

Kabir G. Peay; Thomas D. Bruns; Matteo Garbelotto

2010-01-01

401

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

402

Population-level impacts of pesticide-induced chronic effects on individuals depend more on ecology than toxicology  

Microsoft Academic Search

The current method for assessing long-term risk of pesticides to mammals in the EU is based on the individual rather than the population-level and lacks ecological realism. Hence there is little possibility for regulatory authorities to increase ecological realism and understanding of risks at the population-level. Here we demonstrate how, using ABM modelling, assessments at the population-level can be obtained

T. Dalkvist; C. J. Topping; V. E. Forbes

2009-01-01

403

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

PubMed

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

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

2014-11-01

404

Relevance and Applicability of a Simple Earthworm Biomarker of Copper Exposure. I. Links to Ecological Effects in a Laboratory Study with Eisenia andrei  

Microsoft Academic Search

A simple earthworm biomarker, neutral-red retention by coelomocyte lysosomes, was measured concurrently with ecological parameters in order to link effects at different levels of biological organization in a laboratory study. Exposure of the earthwormEisenia andreito an increasing range of soil copper concentrations in the laboratory indicated a threshold range for the neutral-red assay at soil copper concentrations between 40 and

Claus Svendsen

1997-01-01

405

Coupling the 4M crop model with national geo-databases for assessing the effects of climate change on agro-ecological characteristics of Hungary  

Microsoft Academic Search

The 4M crop model was used to investigate the prospective effects of climate change on the agro-ecological characteristics of Hungary. The model was coupled with a detailed meteorological database and spatial soil information systems covering the whole territory of Hungary. Plant-specific model parameters were determined by inverse modeling. Future meteorological data were produced from the present meteorological data by combining

Nándor Fodor; László Pásztor; Tamás Németh

2012-01-01

406

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

407

Ecological Theory and Community Restoration Ecology  

Microsoft Academic Search

Community ecological theory may play an important role in the development of a science of restoration ecology. Not only will the practice of restoration bene- fit from an increased focus on theory, but basic re- search in community ecology will also benefit. We pose several major thematic questions that are rele- vant to restoration from the perspective of community ecological

Margaret A. Palmer; Richard F. Ambrose; N. LeRoy Poff

1997-01-01

408

Deleterious RAD51C germline mutations rarely predispose to breast and ovarian cancer in Pakistan.  

PubMed

RAD51C plays a key role in homologous recombination-mediated DNA repair and maintenance of genomic stability. Biallelic RAD51C mutations cause Fanconi anemia, and monoallelic mutations predispose women to breast and ovarian cancer. Genetic variability of RAD51C and its impact in Asian populations have been poorly studied. Here, we report the results of comprehensive mutational screening of the RAD51C gene in 348 BRCA1/2-negative breast and/or ovarian cancer patients from Pakistan. Mutation analysis of the complete RAD51C-coding region was performed using denaturing high-performance liquid chromatography analysis, followed by DNA sequencing of variant fragments. Three novel protein-truncating mutations, c.204T>A, c.225T>G, and c.701C>G, were identified. c.204T>A was found in one out of 22 (4.5 %) early-onset (?45 years of age) ovarian cancer patients and c.225T>G in one out of 119 (0.8 %) patients from breast cancer only families. c.701C>G was found in a 60-year-old control with no family history of breast/ovarian cancer. Furthermore, three novel in silico-predicted potentially functional mutations, a missense mutation, c.873T>G, a variant in 5'UTR, c.1-34T>G, and a recurrent intronic variant, c.965+21A>G, were identified. The missense mutation was observed in a patient with bilateral breast cancer from a breast and ovarian cancer family (HBOC), the 5'UTR variant was noted in an early-onset breast cancer patient, and the intronic variant in one early-onset breast cancer patient and one ovarian cancer patient from a HBOC family. Five of the six mutations described were not detected in 400 healthy controls. These findings suggest that RAD51C plays a marginal role in breast and ovarian cancer predisposition in Pakistan. Reliable estimation of the clinical implications of carrying a deleterious RAD51C mutation will require identification of additional mutation-positive patients/families. PMID:24800917

Rashid, Muhammad U; Muhammad, Noor; Faisal, Saima; Amin, Asim; Hamann, Ute

2014-06-01

409

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...

410

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...

411

Exploring the effects of local development regulations on ecological landscape structure  

E-print Network

..................................15 3. Patch- Corridor-Matrix Model ............................................................18 3.1. Landscape Mosaics.........................................................................19 3.2. Patches....11 Analysis of covariance for statistical difference of two sites..........................118 4.12 Descriptive statistics of patch density (PD) ....................................................120 4.13 Significances of between-subjects effects for pre...

Kim, Jin Ki

2005-08-29

412

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

E-print Network

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

McFall-Ngai, Margaret

413

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...

414

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

E-print Network

Ficedula hypoleuca Á Heavy metal pollution Á Reproductive success Á Site fidelity Introduction Breeding hypoleuca) around a point source of heavy metals (a copper smelter). We tested for the effects of sex, age of an insectivorous bird, the pied fly- catcher (Ficedula hypoleuca Pallas), around a point source of heavy metals (a

Laaksonen, Toni

415

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

416

Annotated Bibliography on the Effects of the Physical Environment Upon Education. Ecological Theory of Teaching.  

ERIC Educational Resources Information Center

This annotated bibliography focuses on the effects of the physical environment on education. Topics covered include school size, architectural design, seating arrangement, environmental stressors, alternative learning environments, enhancing learning through environmental change, and special groups of students within the school. The first section…

McDonnell, Thomas; Becker, Franklin

417

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

418

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

419

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

420

Effect of the ecological water conveyance project on environment in the Lower Tarim River, Xinjiang, China  

Microsoft Academic Search

The dynamic response of groundwater level is examined in traverse and lengthways directions. Take the Yinsu section for an\\u000a example, we have simulated groundwater levels before and after water-conveyance every time and calculated the incidence of\\u000a groundwater on the both sides of the river. It is noted that the effect keeps growing with the water-delivery times increasing,\\u000a from 570 m after

Zhaoxia Ye; Yaning Chen; Weihong Li; Yan Yan

2009-01-01

421

Winter ecology of shallow lakes: strongest effect of fish on water clarity at high nutrient levels  

Microsoft Academic Search

While the structuring role of fish in lakes is well studied for the summer season in North temperate lakes, little is known\\u000a about their role in winter when fish activity and light irradiance potentially are lower. This is unfortunate as the progressing\\u000a climate change may have strong effects on lake winter temperature and possibly on trophic dynamics too. We conducted

Torben Sørensen; Gabi Mulderij; Martin Søndergaard; Torben L. Lauridsen; Lone Liboriussen; Sandra Brucet; Erik Jeppesen

2011-01-01

422

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

423

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

SciTech Connect

The Savannah River Site (SRS) is a 780 km{sup 2} U.S. Department of Energy facility near Aiken SC established in 1950 to produce nuclear materials. SRS streams are 'integrators' that potentially receive water transportable contaminants from all sources within their watersheds necessitating a GIS-based watershed approach to organize contaminant distribution data and accurately characterize the effects of multiple contaminant sources on aquatic organisms. Concentrations of metals in sediments, fish, and water were elevated in streams affected by SRS operations, but contaminant exposure models for Lontra Canadensis and Ceryle alcyon indicated that toxicological reference values were exceeded only by Hg and Al. Macroinvertebrate community structure was unrelated to sediment metal concentrations. This study indicated that (1) modeling studies and field bioassessments provide a complementary basis for addressing the individual and cumulative effects of contaminants, (2) habitat effects must be controlled when assessing contaminant impacts, (3) sensitivity analyses of contaminant exposure models are helpful in apportioning sampling effort, and (4) contaminants released during fifty years of industrial operations have not resulted in demonstrable harm to aquatic organisms in SRS streams.

Paller, M.; Dyer, S.

2009-09-01

424

Biophysical and ecological effects of aggrading vegetion on unsaturated water flow in the vadose zone  

NASA Astrophysics Data System (ADS)

A defining challenge in terrestrial ecohydrological research is to understand how vegetation alters water flow through the environment. Vegetation plays a dominant role in the transmission of soil water into the atmosphere during transpiration, though the physiological and biophysical mechanisms by which vegetation alters water flow in the vadose zone have not been well characterized, or quantified. To address this knowledge gap we posed two research questions: 1) does vegetation influence soil structure sufficiently to alter the magnitude of, and time-source contributions to groundwater recharge in aggrading plant communities, and 2) does the evolving vertical distribution of root biomass in aggrading plant communities modify soil-water redistribution sufficiently to affect groundwater recharge rates. To answer these questions we utilized hydrometric measurements from a unique chronological sequence of vegetated lysimeters (from bare soil through five years of grassland aggradation), unsaturated-flow modeling, and new high-frequency measurements of stable-isotope-tracers. Experimentally-derived soil-hydraulic parameters were used to simulate one water year of precipitation, vertically-stratified soil moisture dynamics, and groundwater recharge for an initial bare soil state. Measured precipitation and vegetation parameters were then used to simulate the vadose zone water balance for five years, and a comparative analysis was conducted for the simulated and measured water balance fluxes—in essence, using the model as a change detection tool. This approach allowed us to empirically quantify the biophysical and physiological effects of aggrading vegetation on soil moisture dynamics and groundwater recharge, and to infer how these effects alter the effective-hydraulic parameters used to model unsaturated water flow in the vadose zone. We also employed mixing calculations and a new method for in situ high frequency sampling of stable isotopes that further illustrated a vegetation influence on the time-source contributions to groundwater recharge.

Pangle, L. A.; McDonnell, J. J.

2012-12-01

425

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

426

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

427

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

E-print Network

of the river out- flow on the phytoplankton community in the study area. LITERATURE REVIEW Oil Pol lution and ~Ecolo Most oil pollution studies have been conducted af ter massive spills of oil into the marine environment from tanker accidents or offshore... Channel. A more complete listing of other smaller spills and their effects on marine life is found in Martens (1973). Major oil spills ofi the coast of Louisiana have been cata- logued by the V. S. Geological Survey (see Menzies, 1973). Spills...

Fucik, K

2012-06-07

428

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

SciTech Connect

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, competitors, predators, prey, habitat and other biotic and abiotic factors. Models of population-level effects of contaminants can integrate information from lower levels of biological organization and feed that information into higher-level community and ecosystem models. As individual-level endpoints are utilized to predict population responses, this requires that biological responses at lower levels of organization be translated into a form that is useable by the population modeler. In this paper we describe how mechanistic data, as captured in adverse outcome pathways, can be translated into modeling focused on population-level risk assessments. First, we present a succinct overview of different approaches to population modeling, and discuss the types of data needed for these models. Then we discuss how toxicity data are used currently for population modeling, and provide recommendations as to how testing might be modified to better generate information to support modeling. From this we describe how different key processes measured at the level of the individual serve as the bridge between mechanistic toxicology data and predictions of population status, and provide case examples of how this linkage has been/can be achieved.

Kramer, Vincent J.; Etterson, Matthew A.; Hecker, Markus; Murphy, Cheryl A.; Roesijadi, Guritno; Spade, Daniel J.; Spromberg, Julann A.; Wang, Magnus; Ankley, Gerald T.

2010-11-24

429

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

430

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

431

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

432

Soil erosion and biodiversity - Effects of ecological variables on throughfall kinetic energy for different spatial scales  

NASA Astrophysics Data System (ADS)

To combat soil erosion is a prominent and most important ecosystem service of forests. Yet, little is known about the mechanistic relation of this ecosystem service to biodiversity. We hypothesize that the underlying processes in forests can be explained by (i) mechanisms that alter rainfall properties and (ii) those that change forest floor properties. The present study concentrates on the alteration of rainfall properties by vegetation canopies in a subtropical forest ecosystem in SE-China. The research approach consists of investigations in established forest stands complemented by measurements in a plantation-like experiment. On the level of whole forest stands we relate forest succession, specific species, forest stand variables and species richness as a measure of biodiversity to throughfall kinetic energy (KE) (plot size=900m2). Effects of plant architectural traits, species identity and stand density on throughfall KE were studied more in detail on a smaller spatial scale (plot size=1m2) and related to changes in throughfall KE. On the forest stand level we could identify effects of tree canopy structure (height, leaf area index), diversity (rarefied species number) and functional trait identity (proportion of needle leafed species). Throughfall KE increases with canopy height, biodiversity and an interaction between canopy height and rainfall amount where both factors reinforce each other. It decreases with increasing proportion of needle leafed species within a plot and an increasing LAI. In subtropical broad-leaved forests throughfall KE is largely controlled by forest structure, traits and the number of the species present in the canopy. High coverage and a low total height keeps throughfall KE low in younger plots whereas canopy gaps and a higher total height enlarge the values of throughfall KE in older plots. The variability of throughfall KE is controlled by rainfall intensity and biodiversity which counteract against each other. The variability of throughfall KE is highest in highly diverse plots when the intensity of a given rainfall event is low. For the smaller spatial scale results show that rainfall KE per area was reduced by 59% below the canopy of the studied saplings (height < 1.2m). We found a significant effect of sapling density on throughfall KE. The main cause for this circumstance is the relation between free throughfall and release throughfall. As free throughfall possesses a far higher KE than release throughfall originating from saplings, a lower density results in a higher total throughfall KE. Moreover we could show that the influence of density on throughfall KE decreases with increasing sapling height due to lateral growth and canopy closure of the saplings. Throughfall KE was significantly different between sapling species. We attribute this to species-specific differences in crown architectural traits. These traits influence throughfall KE contrarily and interact with each other. Depending on its magnitude, one crown trait can possibly superimpose contrary effects of others on throughfall KE. For established forests the influence of rainfall properties on throughfall KE is stronger than expected. Interestingly the influence of stand height on throughfall KE depends on the amount of rainfall. Biodiversity, as a measure of dissimilarity, increases the spatial heterogeneity of throughfall KE within a forest stand. At the smaller spatial scale we can state that the ecosystem function of erosion control is being activated gradually. The velocity of crown development is supposed to be the most important factor for this circumstance. Moreover, at this temporal and spatial scale, specific single species are supposed perform better in stabilizing ecosystems threatened by erosion than species mixtures.

Geißler, C.; Nadrowski, K.; Kühn, P.; Baruffol, M.; Lang, A. C.; von Oheimb, G.; Härdtle, W.; Scholten, T.

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